: HOW A LINE INTEGRAL GENRALISES A DEFINIT INTEGRAL KNOWN FROM CALCULUS
Submitted to: Submitted by:
Mr. Brijesh kumar Sinha Yuvraj Singh
Deptt. Of Mathematics RB1803B11
10809366
B.Tech-MBA(cse)
ACKNOWLEDGEMENT
I, express my gratitude towards our subject teacher for the guidelines and help provided by her in making this project a success. She helped me a lot in completing this project.
I would like to say thank you to all those who are involved in this project including my friends. Their valuable inputs in various matter related to the topic helped me a lot.
I have taken the help of many books and websites, listed in references. I would like to thank the library of the university that acted as a database of knowledge for me.
The various sites visited by me on the internet also helped me a lot in making my term paper a success. I thank again one and all.
CONTENTS
1. Line Integral
2. Definite Integral
3. Area under a curve
4. Area using line integral
5. Application of line integral
6. References.
LINE INTEGRAL
The line integral of a vector field on a curve is defined by
(1)
where denotes a dot product. In Cartesian coordinates, the line integral can be written
(2)
where
(3)
For complex and a path in the complex plane parameterized by ,
(4)
Poincaré's theorem states that if in a simply connected neighborhood of a point , then in this neighborhood, is the gradient of a scalar field ,
(5)
for , where is the gradient operator. Consequently, the gradient theorem gives
(6)
for any path located completely within , starting at and ending at .
This means that if (i.e., is an irrotational field in some region), then the line integral is path-independent in this region. If desired, a Cartesian path can therefore be chosen between starting and ending point to give
(7)
If (i.e., is a divergenceless field, a.k.a. solenoidal field), then there exists a vector field such that
(8)
where is uniquely determined up to a gradient field (and which can be chosen so that ).
.
DEFINITE INTEGRAL
A definite integral is an integral
(1)
with upper and lower limits. If is restricted to lie on the real line, the definite integral is known as a Riemann integral (which is the usual definition encountered in elementary textbooks). However, a general definite integral is taken in the complex plane, resulting in the contour integral
(2)
with , , and in general being complex numbers and the path of integration from to known as a contour.
The first fundamental theorem of calculus allows definite integrals to be computed in terms of indefinite integrals, since if is the indefinite integral for a continuous function , then
(3)
This result, while taught early in elementary calculus courses, is actually a very deep result connecting the purely algebraic indefinite integral and the purely analytic (or geometric) definite integral. Definite integrals may be evaluated in Mathematica using Integrate[f, x, a, b ].
AREA UNDER A CURVE
Theory:
The definite integral can be used to find the area between a graph curve and the ‘x’ axis, between two given ‘x’ values. This area is called the ‘area under the curve’ regardless of whether it is above or below the ‘x’ axis.
When the curve is above the ‘x’ axis, the area is the same as the definite integral ...
but when the graph line is below the ‘x’ axis, the definite integral is negative. The area is then given by:
Sometimes part of the graph is above the ‘x’ axis and part is below, then it is necessary to calculate several integrals. When the area of each part is found, the total area can be found by adding the parts.
For example, to find the area between the graph of: y = x² - x - 2 and the ‘x’ axis, from x = -2 to x = 3, we need to calculate three separate integrals:
The zeros of the function f(x) that lie between -2 and 3 form the boundaries of the separate area segments.
In this case there are zeros at x = -1 and x = 2, (see graph above) and so three separate areas must be found: A1, A2 and A3 as follows:
So the total shaded area between the function and the graph from x = -2 to x = 3 is given by:
A = A1 + A2 + A3
Now we can graph the function, locate the zeros and calculate the definite integrals.
AREA USING LINE INTEGRAL
The stated proposition is: if a given region is bounded by a piecewise smooth closed orientable curved then the area is given as a line integral over the curve. We work through examples where both a parameterization is given and where a parameterization will be determined. These examples show that finding area with line integrals can be straightforward.
Proposition (Line Integral for Area) If is a region bounded by a piecewise smooth simple closed curve oriented counterclockwise, then the area of is given by
EXAMPLE
(Line Integral for Area) Use a line integral to find the area enclosed by the region defined by the circle
Solution. We can parametrize the circle by and for Then the area is found by,
Use a line integral to find the area enclosed by the region defined by the triangle with vertices
Solution. We can parametrize the line segments by
Then the area is found by,
APPLICATION OF LINE INTEGRAL
Applications
The line integral has many uses in physics. For example, the work done on a particle traveling on a curve C inside a force field represented as a vector field F is the line integral of F on C.
Complex line integral
The line integral is a fundamental tool in complex analysis. Suppose U is an open subset of C, γ : [a, b] → U is a rectifiable curve and f : U → C is a function. Then the line integral
may be defined by subdividing the interval [a, b] into a = t0 < t1 < ... < tn = b and considering the expression
The integral is then the limit of this sum, as the lengths of the subdivision intervals approach zero.
If γ is a continuously differentiable curve, the line integral can be evaluated as an integral of a function of a real variable:
When γ is a closed curve, that is, its initial and final points coincide, the notation
is often used for the line integral of f along γ.
The line integrals of complex functions can be evaluated using a number of techniques: the integral may be split in to real and imaginary parts reducing the problem to that of evaluating two real-valued line integrals, the Cauchy integral formula may be used in other circumstances. If the line integral is a closed curve in a region where the function is analytic and containing no singularities, then the value of the integral is simply zero, this is a consequence of the Cauchy integral theorem. Because of the residue theorem, one can often use contour integrals in the complex plane to find integrals of real-valued functions of a real variable
REFERENCE
www.wikipedia.com
www.mathworld.com
www.about.com
www.britannica.com
Engineering Mathematics- H.K.Das
Encarta Encyclopedia
Saturday, May 9, 2009
Complete description of Rutherford scattering experiment with quantitative analysis, Scattering formula
TERM PAPER
MODERN PHYSICS AND ELECTRONICS
PHY112
Topic: Complete description of Rutherford scattering experiment with quantitative analysis, Scattering formula
ACKNOWLEDGEMENT
I, express my gratitude towards our subject teacher for the guidelines and help provided by her in making this project a success. She helped me a lot in completing this project.
I would like to say thank you to all those who are involved in this project including my friends. Their valuable inputs in various matter related to the topic helped me a lot.
I have taken the help of many books and websites, listed in references. I would like to thank the library of the university that acted as a database of knowledge for me.
The various sites visited by me on the internet also helped me a lot in making my term paper a success. I thank again one and all.
CONTENTS
Introduction
Thompson’s plum pudding model
Rutherford’s model
Failure of Rutherford’s model
Bohr’s atomic model
Shortcoming of bohr’s model
Reference
INTRODUCTION
In chemistry and physics, atomic theory is a theory of the nature of matter, which states that matter is composed of discrete units called atoms, as opposed to the obsolete notion that matter could be divided into any arbitrarily small quantity. It began as a philosophical concept in ancient Greece and India and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of particles.
The word "atom" (from the Greek atomos, "indivisible"[1]) was applied to the basic particle that constituted a chemical element, because the chemists of the era believed that these were the fundamental particles of matter. However, around the turn of the 20th century, through various experiments with electromagnetism and radioactivity, physicists discovered that the so-called "indivisible atom" was actually a conglomerate of various subatomic particles (chiefly, electrons, protons and neutrons) which can exist separately from each other. In fact, in certain extreme environments such as neutron stars, extreme temperature and pressure prevents atoms from existing at all. Since atoms were found to be actually divisible, physicists later invented the term "elementary particles" to describe indivisible particles. The field of science which studies subatomic particles is particle physics, and it is in this field that physicists hope to discover the true fundamental nature of matter.
Thompson’s Plum pudding model
A schematic representation of the plum pudding model of the atom. In Thomson's mathematical model the "corpuscles" (or modern electrons) were arranged non-randomly, in rotating rings.
The plum pudding model of the atom by J.J. Thomson, who discovered the electron in 1897, was proposed in 1904 before the discovery of the atomic nucleus. In this model, the atom is composed of electrons (which Thomson still called "corpuscles," though G.J. Stoney had proposed that atoms of electricity be called electrons in 1894) [1] , surrounded by a soup of positive charge to balance the electron's negative charge, like negatively-charged "plums" surrounded by positively-charged "pudding". The electrons (as we know them today) were thought to be positioned throughout the atom, but with many structures possible for positioning multiple electrons, particularly rotating rings of electrons (see below). Instead of a soup, the atom was also sometimes said to have had a cloud of positive charge.
The model was disproved by the 1909 gold foil experiment, which was interpreted by Ernest Rutherford in 1911[2] to imply a very small nucleus of the atom containing a very high positive charge (enough to balance about 100 electrons in gold), thus leading to the Rutherford model of the atom, and finally (after Henry Moseley's work showed in 1913 that the nuclear charge was very close to the atomic number) to the Antonius Van den Broek suggestion that atomic number is nuclear charge. Eventually, by 1913, this work had culminated in the solar-system-like (but quantum-limited) Bohr model of the atom, in which a nucleus containing an atomic number of positive charge is surrounded by an equal number of electrons in orbital shells.
Thomson's model was compared (though not by Thomson) to a British treat called plum pudding, hence the name. It has also been called the chocolate chip cookie model or blueberry muffin model, but these mental pictures assume the particles as static, which they were not for Thomson.
Thomson's paper was published in the March 1904 edition of the Philosophical Magazine, the leading British science journal of the day. In Thompson's view:
... the atoms of the elements consist of a number of negatively electrified corpuscles enclosed in a sphere of uniform positive electrification, ...
In this model, the electrons were free to rotate within the blob or cloud of positive substance. These orbits were stabilized in the model by the fact that when an electron moved farther from the center of the positive cloud, it felt a larger net positive inward force, because there was more material of opposite charge, inside its orbit (see Gauss's law). In Thomson's model, electrons were free to rotate in rings which were further stabilized by interactions between the electrons, and spectra were to be accounted for by energy differences of different ring orbits. Thomson attempted to make his model account for some of the major spectral lines known for some elements, but was not notably successful at this. Still, Thomson's model (along with a similar Saturnian ring model for atomic electrons, put forward also in 1904 by Nagaoka after the Maxwell model of Saturn's rings), were earlier harbingers of the later and more successful solar-system-like Bohr model of the atom.
Rutherford model
A stylised representation of the Rutherford model of a lithium atom (nuclear structure anachronistic)
The Rutherford model or planetary model is a model of the atom devised by Ernest Rutherford. Rutherford directed the famous Geiger-Marsden experiment in (1909), which suggested to Rutherford's analysis (1911) that the Plum pudding model (of J. J. Thomson) of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, had a number of essential modern features, including a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and containing the bulk of the atomic mass (the nucleus of the atom), and a number of tiny electrons circling around the nucleus like planets around the sun.
Experimental basis for the model
In 1911, Rutherford came forth with his own physical model for subatomic structure, as an interpretation for the unexpected experimental results. In it, the atom is made up of a central charge (this is the modern atomic nucleus, though Rutherford did not use the term "nucleus" in his paper) surrounded by a cloud of orbiting electrons. In this 1911 paper, Rutherford only commits himself to a small central region of very high positive or negative charge in the atom, but uses the following language for pictorial purposes:
"For concreteness, consider the passage of a high speed α particle through an atom having a positive central charge N e, and surrounded by a compensating charge of N electrons. [1]
From purely energetic considerations of how far α (alpha) particles of known speed would be able to penetrate toward a central charge of 100 e, Rutherford was able to calculate that the radius of his gold central charge would need to be less (how much less could not be told) than 3.4 x 10-14 metres (the modern value is only about a fifth of this). This was in a gold atom known to be 10-10 metres or so in radius--- a very surprising finding, as it implied a strong central charge less than 1/3000th of the diameter of the atom.
The Rutherford model didn't attribute any structure to the orbits of the electrons themselves, though it did mention the atomic model of Hantaro Nagaoka, in which the electrons are arranged in one or more rings.
The Rutherford paper suggested that the central charge of an atom might be "proportional" to its atomic mass in hydrogen mass units (roughly 1/2 of it, in Rutherford's model). For gold, this mass number is 197 (not then known to great accuracy) and was therefore modeled by Rutherford to be possibly 196. However, Rutherford did not attempt to make the direct connection of central charge to atomic number, since gold's place on the periodic table was known to be about 79, and Rutherford's more tentative model for the structure of the gold nucleus was 49 helium nuclei, which would have given it a mass of 196 and charge of 98. This differed enough from gold's "atomic number" (at that time merely its place number in the periodic table) that Rutherford did not formally suggest the two numbers might be exactly the same.
Key points of Rutherford model
• The electron clouds of the atom do not influence alpha scattering.
• A large number of the atom's charges, up to a number equal to about half the atomic mass in hydrogen units, are concentrated in very small volume at the center of the atom. These are responsible for deflecting both alpha and beta particles.
• The mass of heavy atoms such as gold is mostly concentrated in the central charge region, since calculations show it is not deflected or moved by the high speed alpha particles, which have very high momentum in comparison to electrons, but not with regard to heavy atoms (such as gold) on the whole. This suggests that much of the mass of atoms is concentrated in their centres.
Shorcomings of Rutherfords model
Rutherford naturally considered a planetary-model atom, the Rutherford model of 1911 – electrons orbiting a solar nucleus – however, said planetary-model atom has a technical difficulty. The laws of classical mechanics (i.e. the Larmor formula), predict that the electron will release electromagnetic radiation while orbiting a nucleus. Because the electron would lose energy, it would gradually spiral inwards, collapsing into the nucleus. This atom model is disastrous, because it predicts that all atoms are unstable.
Also, as the electron spirals inward, the emission would gradually increase in frequency as the orbit got smaller and faster. This would produce a continuous smear, in frequency, of electromagnetic radiation. However, late 19th century experiments with electric discharges through various low-pressure gasses in evacuated glass tubes had shown that atoms will only emit light (that is, electromagnetic radiation) at certain discrete frequencies.
T
Bohr model
Introduced by Niels Bohr in 1913, the model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen. While the Rydberg formula had been known experimentally, it did not gain a theoretical underpinning until the Bohr model was introduced. Not only did the Bohr model explain the reason for the structure of the Rydberg formula, but it provided a justification for its empirical results in terms of fundamental physical constants.
The Bohr model is a primitive model of the hydrogen atom. As a theory, it can be derived as a first-order approximation of the hydrogen atom using the broader and much more accurate quantum mechanics, and thus may be considered to be an obsolete scientific theory. However, because of its simplicity, and its correct results for selected systems (see below for application), the Bohr model is still commonly taught to introduce students to quantum mechanics, before moving on to the more accurate but more complex valence shell atom. A related model was originally proposed by Arthur Erich Haas in 1910, but was rejected. The quantum theory of the period between Planck's discovery of the quantum (1900) and the advent of a full-blown quantum mechanics (1925) is often referred to as the old quantum theory.
o
Origin
In the early 20th century, experiments by Ernest Rutherford established that atoms consisted of a diffuse cloud of negatively charged electrons surrounding a small, dense, positively charged nucleus. Given this experimental data, Rutherford naturally considered a planetary-model atom, the Rutherford model of 1911 – electrons orbiting a solar nucleus – however, said planetary-model atom has a technical difficulty. The laws of classical mechanics (i.e. the Larmor formula), predict that the electron will release electromagnetic radiation while orbiting a nucleus. Because the electron would lose energy, it would gradually spiral inwards, collapsing into the nucleus. This atom model is disastrous, because it predicts that all atoms are unstable.
Also, as the electron spirals inward, the emission would gradually increase in frequency as the orbit got smaller and faster. This would produce a continuous smear, in frequency, of electromagnetic radiation. However, late 19th century experiments with electric discharges through various low-pressure gasses in evacuated glass tubes had shown that atoms will only emit light (that is, electromagnetic radiation) at certain discrete frequencies.
To overcome this difficulty, Niels Bohr proposed, in 1913, what is now called the Bohr model of the atom. He suggested that electrons could only have certain classical motions:
1. The electrons can only travel in special orbits: at a certain discrete set of distances from the nucleus with specific energies.
2. The electrons do not continuously lose energy as they travel. They can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency ν determined by the energy difference of the levels according to the Planck relation:
where h is Planck's constant.
3. The frequency of the radiation emitted at an orbit of period T is as it would be in classical mechanics; it is the reciprocal of the classical orbit period:
The significance of the Bohr model is that the laws of classical mechanics apply to the motion of the electron about the nucleus only when restricted by a quantum rule. Although rule 3 is not completely well defined for small orbits, because the emission process involves two orbits with two different periods, Bohr could determine the energy spacing between levels using rule 3 and come to an exactly correct quantum rule: the angular momentum L is restricted to be an integer multiple of a fixed unit:
where n = 1, 2, 3, ... is called the principal quantum number, and ħ = h/2π. The lowest value of n is 1; this gives a smallest possible orbital radius of 0.0529 nm known as the Bohr radius. Once an electron is in this lowest orbit, it can get no closer to the proton. Starting from the angular momentum quantum rule Bohr[1] was able to calculate the energies of the allowed orbits of the hydrogen atom and other hydrogen-like atoms and ions.
Other points are:
1. Like Einstein's theory of the Photoelectric effect, Bohr's formula assumes that during a quantum jump a discrete amount of energy is radiated. However, unlike Einstein, Bohr stuck to the classical Maxwell theory of the electromagnetic field. Quantization of the electromagnetic field was explained by the discreteness of the atomic energy levels; Bohr did not believe in the existence of photons.
2. According to the Maxwell theory the frequency ν of classical radiation is equal to the rotation frequency νrot of the electron in its orbit, with harmonics at integer multiples of this frequency. This result is obtained from the Bohr model for jumps between energy levels En and En−k when k is much smaller than n. These jumps reproduce the frequency of the k-th harmonic of orbit n. For sufficiently large values of n (so-called Rydberg states), the two orbits involved in the emission process have nearly the same rotation frequency, so that the classical orbital frequency is not ambiguous. But for small n (or large k), the radiation frequency has no unambiguous classical interpretation. This marks the birth of the correspondence principle, requiring quantum theory to agree with the classical theory only in the limit of large quantum numbers.
3. The Bohr-Kramers-Slater theory (BKS theory) is a failed attempt to extend the Bohr model which violates the conservation of energy and momentum in quantum jumps, with the conservation laws only holding on average.
Bohr's condition, that the angular momentum is an integer multiple of ħ was later reinterpreted by de Broglie as a standing wave condition: the electron is described by a wave and a whole number of wavelengths must fit along the circumference of the electron's orbit:
Substituting de Broglie's wavelength reproduces Bohr's rule. Bohr justified his rule by appealing to the correspondence principle, without providing a wave interpretation.
In 1925 a new kind of mechanics was proposed, quantum mechanics in which Bohr's model of electrons traveling in quantized orbits was extended into a more accurate model of electron motion. The new theory was proposed by Werner Heisenberg. Another form of the same theory, modern quantum mechanics, was discovered by the Austrian physicist Erwin Schrödinger independently and by different reasoning.
Electron energy levels
The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light. This not only includes one-electron systems such as the hydrogen atom, singly-ionized helium, doubly ionized lithium, but it includes positronium and Rydberg states of any atom where one electron is far away from everything else. It can be used for K-line X-ray transition calculations if other assumptions are added (see Moseley's law below). In high energy physics, it can be used to calculate the masses of heavy quark mesons.
To calculate the orbits requires two assumptions:
1. Classical mechanics
The electron is held in a circular orbit by electrostatic attraction. The centripetal force is equal to the Coulomb force.
where me is the mass, e is the charge of the electron and ke is Coulomb's constant. This determines the speed at any radius:
It also determines the total energy at any radius:
The total energy is negative and inversely proportional to r. This means that it takes energy to pull the orbiting electron away from the proton. For infinite values of r, the energy is zero, corresponding to a motionless electron infinitely far from the proton. The total energy is half the potential energy, which is true for non circular orbits too by the virial theorem.
For larger nuclei, the only change is that kee2 is everywhere replaced by Zkee2 where Z is the number of protons. For positronium, me is replaced by its reduced mass (μ = me/2).
2. Quantum rule
The angular momentum L = mevr is an integer multiple of ħ:
Substituting the expression for the velocity gives an equation for r in terms of n:
so that the allowed orbit radius at any n is:
The smallest possible value of r is called the Bohr radius and is equal to:
The energy of the n-th level is determined by the radius:
An electron in the lowest energy level of hydrogen (n = 1) therefore has 13.6 eV less energy than a motionless electron infinitely far from the nucleus. The next energy level (n = 2) is −3.4 eV. The third (n = 3) is −1.51 eV, and so on. For larger values of n, these are also the binding energies of a highly excited atom with one electron in a large circular orbit around the rest of the atom.
The combination of natural constants in the energy formula is called the Rydberg energy (RE):
This expression is clarified by interpreting it in combinations which form more natural units:
is the rest mass energy of the electron (511 keV/c)
is the fine structure constant
Since this derivation is with the assumption that the nucleus is orbited by one electron, we can generalize this result by letting the nucleus have a charge q = Ze where Z is the atomic number. This will now give us energy levels for hydrogenic atoms, which can serve as a rough order-of-magnitude approximation of the actual energy levels. So, for nuclei with Z protons, the energy levels are (to a rough approximation):
The actual energy levels cannot be solved analytically for more than one electron (see n-body problem) because the electrons are not only affected by the nucleus but also interact with each other via the Coulomb Force. However, the analytic soltuion can be approximated using the Hartee-Fock method, which involves replacing "Z" with "Z - b" where b is constant representing electric field screening due to the inner-shell electron(s) (see Electron shell and the later discussion of the "Shell Model of the Atom" below).
When Z = 1/α (Z ≈ 137), the motion becomes highly relativistic, and Z2 cancels the α2 in R; the orbit energy begins to be comparable to rest energy. Sufficiently large nuclei, if they were stable, would reduce their charge by creating a bound electron from the vacuum, ejecting the positron to infinity. This is the theoretical phenomenon of electromagnetic charge screening which predicts a maximum nuclear charge. Emission of such positrons has been observed in the collisions of heavy ions to create temporary super-heavy nuclei.[citation needed]
For positronium, the formula uses the reduced mass. For any value of the radius, the electron and the positron are each moving at half the speed around their common center of mass, and each has only one fourth the kinetic energy. The total kinetic energy is half what it would be for a single electron moving around a heavy nucleus.
(positronium)
Shortcomings
The Bohr model gives an incorrect value for the ground state orbital angular momentum. The angular momentum in the true ground state is known to be zero. Although mental pictures fail somewhat at these levels of scale, an electron in the lowest modern "orbital" with no orbital momentum, may be thought of as not to rotate "around" the nucleus at all, but merely to go tightly around it in an ellipse with zero area (this may be pictured as "back and forth", without striking or interacting with the nucleus). This is only reproduced in a more sophisticated semiclassical treatment like Sommerfeld's. Still, even the most sophisticated semiclassical model fails to explain the fact that the lowest energy state is spherically symmetric--- it doesn't point in any particular direction.
In modern quantum mechanics, the electron in hydrogen is a spherical cloud of probability which grows denser near the nucleus. The rate-constant of probability-decay in hydrogen is equal to the inverse of the Bohr radius, but since Bohr worked with circular orbits, not zero area ellipses, the fact that these two numbers exactly agree, is considered a "coincidence." (Though many such coincidental agreements are found between the semi-classical vs. full quantum mechanical treatment of the atom; these include identical energy levels in the hydrogen atom, and the derivation of a fine structure constant, which arises from the relativistic Bohr-Sommerfield model (see below), and which happens to be equal to an entirely different concept, in full modern quantum mechanics).
The Bohr model also has difficulty with, or else fails to explain:
• Much of the spectra of larger atoms. At best, it can make predictions about the K-alpha and some L-alpha X-ray emission spectra for larger atoms, if two additional ad hoc assumptions are made (see Moseley's law above). Emission spectra for atoms with a single outer-shell electron (atoms in the lithium group) can also be approximately predicted. Also, if the empiric electron-nuclear screening factors for many atoms are known, many other spectral lines can be deduced from the information, in similar atoms of differing elements, via the Ritz-Rydberg combination principles (see Rydberg formula). All these techniques essentially make use of Bohr's Newtonian energy-potential picture of the atom.
• The theory does not predict the relative intensities of spectral lines; although in some simple cases, Bohr's formula or modifications of it, was able to provide reasonable estimates (for example, calculations by Kramers for the Stark effect).
• The existence of fine structure and hyperfine structure in spectral lines, which are known to be due to a variety of relativistic and subtle effects, as well as complications from electron spin.
• The Zeeman effect - changes in spectral lines due to external magnetic fields; these are also due to more complicated quantum principles interacting with electron spin and orbital magnetic fields.
• The model also violates the uncertainty principle in that it considers electrons to have known orbits and definite radius, two things which can not be directly known at once.
REFERENCE
www.about.com
www.wikipedia.com
www.physicstoday.com
Encarta encyclopedia
Modern Physics- Arthurbeizer
MODERN PHYSICS AND ELECTRONICS
PHY112
Topic: Complete description of Rutherford scattering experiment with quantitative analysis, Scattering formula
ACKNOWLEDGEMENT
I, express my gratitude towards our subject teacher for the guidelines and help provided by her in making this project a success. She helped me a lot in completing this project.
I would like to say thank you to all those who are involved in this project including my friends. Their valuable inputs in various matter related to the topic helped me a lot.
I have taken the help of many books and websites, listed in references. I would like to thank the library of the university that acted as a database of knowledge for me.
The various sites visited by me on the internet also helped me a lot in making my term paper a success. I thank again one and all.
CONTENTS
Introduction
Thompson’s plum pudding model
Rutherford’s model
Failure of Rutherford’s model
Bohr’s atomic model
Shortcoming of bohr’s model
Reference
INTRODUCTION
In chemistry and physics, atomic theory is a theory of the nature of matter, which states that matter is composed of discrete units called atoms, as opposed to the obsolete notion that matter could be divided into any arbitrarily small quantity. It began as a philosophical concept in ancient Greece and India and entered the scientific mainstream in the early 19th century when discoveries in the field of chemistry showed that matter did indeed behave as if it were made up of particles.
The word "atom" (from the Greek atomos, "indivisible"[1]) was applied to the basic particle that constituted a chemical element, because the chemists of the era believed that these were the fundamental particles of matter. However, around the turn of the 20th century, through various experiments with electromagnetism and radioactivity, physicists discovered that the so-called "indivisible atom" was actually a conglomerate of various subatomic particles (chiefly, electrons, protons and neutrons) which can exist separately from each other. In fact, in certain extreme environments such as neutron stars, extreme temperature and pressure prevents atoms from existing at all. Since atoms were found to be actually divisible, physicists later invented the term "elementary particles" to describe indivisible particles. The field of science which studies subatomic particles is particle physics, and it is in this field that physicists hope to discover the true fundamental nature of matter.
Thompson’s Plum pudding model
A schematic representation of the plum pudding model of the atom. In Thomson's mathematical model the "corpuscles" (or modern electrons) were arranged non-randomly, in rotating rings.
The plum pudding model of the atom by J.J. Thomson, who discovered the electron in 1897, was proposed in 1904 before the discovery of the atomic nucleus. In this model, the atom is composed of electrons (which Thomson still called "corpuscles," though G.J. Stoney had proposed that atoms of electricity be called electrons in 1894) [1] , surrounded by a soup of positive charge to balance the electron's negative charge, like negatively-charged "plums" surrounded by positively-charged "pudding". The electrons (as we know them today) were thought to be positioned throughout the atom, but with many structures possible for positioning multiple electrons, particularly rotating rings of electrons (see below). Instead of a soup, the atom was also sometimes said to have had a cloud of positive charge.
The model was disproved by the 1909 gold foil experiment, which was interpreted by Ernest Rutherford in 1911[2] to imply a very small nucleus of the atom containing a very high positive charge (enough to balance about 100 electrons in gold), thus leading to the Rutherford model of the atom, and finally (after Henry Moseley's work showed in 1913 that the nuclear charge was very close to the atomic number) to the Antonius Van den Broek suggestion that atomic number is nuclear charge. Eventually, by 1913, this work had culminated in the solar-system-like (but quantum-limited) Bohr model of the atom, in which a nucleus containing an atomic number of positive charge is surrounded by an equal number of electrons in orbital shells.
Thomson's model was compared (though not by Thomson) to a British treat called plum pudding, hence the name. It has also been called the chocolate chip cookie model or blueberry muffin model, but these mental pictures assume the particles as static, which they were not for Thomson.
Thomson's paper was published in the March 1904 edition of the Philosophical Magazine, the leading British science journal of the day. In Thompson's view:
... the atoms of the elements consist of a number of negatively electrified corpuscles enclosed in a sphere of uniform positive electrification, ...
In this model, the electrons were free to rotate within the blob or cloud of positive substance. These orbits were stabilized in the model by the fact that when an electron moved farther from the center of the positive cloud, it felt a larger net positive inward force, because there was more material of opposite charge, inside its orbit (see Gauss's law). In Thomson's model, electrons were free to rotate in rings which were further stabilized by interactions between the electrons, and spectra were to be accounted for by energy differences of different ring orbits. Thomson attempted to make his model account for some of the major spectral lines known for some elements, but was not notably successful at this. Still, Thomson's model (along with a similar Saturnian ring model for atomic electrons, put forward also in 1904 by Nagaoka after the Maxwell model of Saturn's rings), were earlier harbingers of the later and more successful solar-system-like Bohr model of the atom.
Rutherford model
A stylised representation of the Rutherford model of a lithium atom (nuclear structure anachronistic)
The Rutherford model or planetary model is a model of the atom devised by Ernest Rutherford. Rutherford directed the famous Geiger-Marsden experiment in (1909), which suggested to Rutherford's analysis (1911) that the Plum pudding model (of J. J. Thomson) of the atom was incorrect. Rutherford's new model for the atom, based on the experimental results, had a number of essential modern features, including a relatively high central charge concentrated into a very small volume in comparison to the rest of the atom and containing the bulk of the atomic mass (the nucleus of the atom), and a number of tiny electrons circling around the nucleus like planets around the sun.
Experimental basis for the model
In 1911, Rutherford came forth with his own physical model for subatomic structure, as an interpretation for the unexpected experimental results. In it, the atom is made up of a central charge (this is the modern atomic nucleus, though Rutherford did not use the term "nucleus" in his paper) surrounded by a cloud of orbiting electrons. In this 1911 paper, Rutherford only commits himself to a small central region of very high positive or negative charge in the atom, but uses the following language for pictorial purposes:
"For concreteness, consider the passage of a high speed α particle through an atom having a positive central charge N e, and surrounded by a compensating charge of N electrons. [1]
From purely energetic considerations of how far α (alpha) particles of known speed would be able to penetrate toward a central charge of 100 e, Rutherford was able to calculate that the radius of his gold central charge would need to be less (how much less could not be told) than 3.4 x 10-14 metres (the modern value is only about a fifth of this). This was in a gold atom known to be 10-10 metres or so in radius--- a very surprising finding, as it implied a strong central charge less than 1/3000th of the diameter of the atom.
The Rutherford model didn't attribute any structure to the orbits of the electrons themselves, though it did mention the atomic model of Hantaro Nagaoka, in which the electrons are arranged in one or more rings.
The Rutherford paper suggested that the central charge of an atom might be "proportional" to its atomic mass in hydrogen mass units (roughly 1/2 of it, in Rutherford's model). For gold, this mass number is 197 (not then known to great accuracy) and was therefore modeled by Rutherford to be possibly 196. However, Rutherford did not attempt to make the direct connection of central charge to atomic number, since gold's place on the periodic table was known to be about 79, and Rutherford's more tentative model for the structure of the gold nucleus was 49 helium nuclei, which would have given it a mass of 196 and charge of 98. This differed enough from gold's "atomic number" (at that time merely its place number in the periodic table) that Rutherford did not formally suggest the two numbers might be exactly the same.
Key points of Rutherford model
• The electron clouds of the atom do not influence alpha scattering.
• A large number of the atom's charges, up to a number equal to about half the atomic mass in hydrogen units, are concentrated in very small volume at the center of the atom. These are responsible for deflecting both alpha and beta particles.
• The mass of heavy atoms such as gold is mostly concentrated in the central charge region, since calculations show it is not deflected or moved by the high speed alpha particles, which have very high momentum in comparison to electrons, but not with regard to heavy atoms (such as gold) on the whole. This suggests that much of the mass of atoms is concentrated in their centres.
Shorcomings of Rutherfords model
Rutherford naturally considered a planetary-model atom, the Rutherford model of 1911 – electrons orbiting a solar nucleus – however, said planetary-model atom has a technical difficulty. The laws of classical mechanics (i.e. the Larmor formula), predict that the electron will release electromagnetic radiation while orbiting a nucleus. Because the electron would lose energy, it would gradually spiral inwards, collapsing into the nucleus. This atom model is disastrous, because it predicts that all atoms are unstable.
Also, as the electron spirals inward, the emission would gradually increase in frequency as the orbit got smaller and faster. This would produce a continuous smear, in frequency, of electromagnetic radiation. However, late 19th century experiments with electric discharges through various low-pressure gasses in evacuated glass tubes had shown that atoms will only emit light (that is, electromagnetic radiation) at certain discrete frequencies.
T
Bohr model
Introduced by Niels Bohr in 1913, the model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen. While the Rydberg formula had been known experimentally, it did not gain a theoretical underpinning until the Bohr model was introduced. Not only did the Bohr model explain the reason for the structure of the Rydberg formula, but it provided a justification for its empirical results in terms of fundamental physical constants.
The Bohr model is a primitive model of the hydrogen atom. As a theory, it can be derived as a first-order approximation of the hydrogen atom using the broader and much more accurate quantum mechanics, and thus may be considered to be an obsolete scientific theory. However, because of its simplicity, and its correct results for selected systems (see below for application), the Bohr model is still commonly taught to introduce students to quantum mechanics, before moving on to the more accurate but more complex valence shell atom. A related model was originally proposed by Arthur Erich Haas in 1910, but was rejected. The quantum theory of the period between Planck's discovery of the quantum (1900) and the advent of a full-blown quantum mechanics (1925) is often referred to as the old quantum theory.
o
Origin
In the early 20th century, experiments by Ernest Rutherford established that atoms consisted of a diffuse cloud of negatively charged electrons surrounding a small, dense, positively charged nucleus. Given this experimental data, Rutherford naturally considered a planetary-model atom, the Rutherford model of 1911 – electrons orbiting a solar nucleus – however, said planetary-model atom has a technical difficulty. The laws of classical mechanics (i.e. the Larmor formula), predict that the electron will release electromagnetic radiation while orbiting a nucleus. Because the electron would lose energy, it would gradually spiral inwards, collapsing into the nucleus. This atom model is disastrous, because it predicts that all atoms are unstable.
Also, as the electron spirals inward, the emission would gradually increase in frequency as the orbit got smaller and faster. This would produce a continuous smear, in frequency, of electromagnetic radiation. However, late 19th century experiments with electric discharges through various low-pressure gasses in evacuated glass tubes had shown that atoms will only emit light (that is, electromagnetic radiation) at certain discrete frequencies.
To overcome this difficulty, Niels Bohr proposed, in 1913, what is now called the Bohr model of the atom. He suggested that electrons could only have certain classical motions:
1. The electrons can only travel in special orbits: at a certain discrete set of distances from the nucleus with specific energies.
2. The electrons do not continuously lose energy as they travel. They can only gain and lose energy by jumping from one allowed orbit to another, absorbing or emitting electromagnetic radiation with a frequency ν determined by the energy difference of the levels according to the Planck relation:
where h is Planck's constant.
3. The frequency of the radiation emitted at an orbit of period T is as it would be in classical mechanics; it is the reciprocal of the classical orbit period:
The significance of the Bohr model is that the laws of classical mechanics apply to the motion of the electron about the nucleus only when restricted by a quantum rule. Although rule 3 is not completely well defined for small orbits, because the emission process involves two orbits with two different periods, Bohr could determine the energy spacing between levels using rule 3 and come to an exactly correct quantum rule: the angular momentum L is restricted to be an integer multiple of a fixed unit:
where n = 1, 2, 3, ... is called the principal quantum number, and ħ = h/2π. The lowest value of n is 1; this gives a smallest possible orbital radius of 0.0529 nm known as the Bohr radius. Once an electron is in this lowest orbit, it can get no closer to the proton. Starting from the angular momentum quantum rule Bohr[1] was able to calculate the energies of the allowed orbits of the hydrogen atom and other hydrogen-like atoms and ions.
Other points are:
1. Like Einstein's theory of the Photoelectric effect, Bohr's formula assumes that during a quantum jump a discrete amount of energy is radiated. However, unlike Einstein, Bohr stuck to the classical Maxwell theory of the electromagnetic field. Quantization of the electromagnetic field was explained by the discreteness of the atomic energy levels; Bohr did not believe in the existence of photons.
2. According to the Maxwell theory the frequency ν of classical radiation is equal to the rotation frequency νrot of the electron in its orbit, with harmonics at integer multiples of this frequency. This result is obtained from the Bohr model for jumps between energy levels En and En−k when k is much smaller than n. These jumps reproduce the frequency of the k-th harmonic of orbit n. For sufficiently large values of n (so-called Rydberg states), the two orbits involved in the emission process have nearly the same rotation frequency, so that the classical orbital frequency is not ambiguous. But for small n (or large k), the radiation frequency has no unambiguous classical interpretation. This marks the birth of the correspondence principle, requiring quantum theory to agree with the classical theory only in the limit of large quantum numbers.
3. The Bohr-Kramers-Slater theory (BKS theory) is a failed attempt to extend the Bohr model which violates the conservation of energy and momentum in quantum jumps, with the conservation laws only holding on average.
Bohr's condition, that the angular momentum is an integer multiple of ħ was later reinterpreted by de Broglie as a standing wave condition: the electron is described by a wave and a whole number of wavelengths must fit along the circumference of the electron's orbit:
Substituting de Broglie's wavelength reproduces Bohr's rule. Bohr justified his rule by appealing to the correspondence principle, without providing a wave interpretation.
In 1925 a new kind of mechanics was proposed, quantum mechanics in which Bohr's model of electrons traveling in quantized orbits was extended into a more accurate model of electron motion. The new theory was proposed by Werner Heisenberg. Another form of the same theory, modern quantum mechanics, was discovered by the Austrian physicist Erwin Schrödinger independently and by different reasoning.
Electron energy levels
The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light. This not only includes one-electron systems such as the hydrogen atom, singly-ionized helium, doubly ionized lithium, but it includes positronium and Rydberg states of any atom where one electron is far away from everything else. It can be used for K-line X-ray transition calculations if other assumptions are added (see Moseley's law below). In high energy physics, it can be used to calculate the masses of heavy quark mesons.
To calculate the orbits requires two assumptions:
1. Classical mechanics
The electron is held in a circular orbit by electrostatic attraction. The centripetal force is equal to the Coulomb force.
where me is the mass, e is the charge of the electron and ke is Coulomb's constant. This determines the speed at any radius:
It also determines the total energy at any radius:
The total energy is negative and inversely proportional to r. This means that it takes energy to pull the orbiting electron away from the proton. For infinite values of r, the energy is zero, corresponding to a motionless electron infinitely far from the proton. The total energy is half the potential energy, which is true for non circular orbits too by the virial theorem.
For larger nuclei, the only change is that kee2 is everywhere replaced by Zkee2 where Z is the number of protons. For positronium, me is replaced by its reduced mass (μ = me/2).
2. Quantum rule
The angular momentum L = mevr is an integer multiple of ħ:
Substituting the expression for the velocity gives an equation for r in terms of n:
so that the allowed orbit radius at any n is:
The smallest possible value of r is called the Bohr radius and is equal to:
The energy of the n-th level is determined by the radius:
An electron in the lowest energy level of hydrogen (n = 1) therefore has 13.6 eV less energy than a motionless electron infinitely far from the nucleus. The next energy level (n = 2) is −3.4 eV. The third (n = 3) is −1.51 eV, and so on. For larger values of n, these are also the binding energies of a highly excited atom with one electron in a large circular orbit around the rest of the atom.
The combination of natural constants in the energy formula is called the Rydberg energy (RE):
This expression is clarified by interpreting it in combinations which form more natural units:
is the rest mass energy of the electron (511 keV/c)
is the fine structure constant
Since this derivation is with the assumption that the nucleus is orbited by one electron, we can generalize this result by letting the nucleus have a charge q = Ze where Z is the atomic number. This will now give us energy levels for hydrogenic atoms, which can serve as a rough order-of-magnitude approximation of the actual energy levels. So, for nuclei with Z protons, the energy levels are (to a rough approximation):
The actual energy levels cannot be solved analytically for more than one electron (see n-body problem) because the electrons are not only affected by the nucleus but also interact with each other via the Coulomb Force. However, the analytic soltuion can be approximated using the Hartee-Fock method, which involves replacing "Z" with "Z - b" where b is constant representing electric field screening due to the inner-shell electron(s) (see Electron shell and the later discussion of the "Shell Model of the Atom" below).
When Z = 1/α (Z ≈ 137), the motion becomes highly relativistic, and Z2 cancels the α2 in R; the orbit energy begins to be comparable to rest energy. Sufficiently large nuclei, if they were stable, would reduce their charge by creating a bound electron from the vacuum, ejecting the positron to infinity. This is the theoretical phenomenon of electromagnetic charge screening which predicts a maximum nuclear charge. Emission of such positrons has been observed in the collisions of heavy ions to create temporary super-heavy nuclei.[citation needed]
For positronium, the formula uses the reduced mass. For any value of the radius, the electron and the positron are each moving at half the speed around their common center of mass, and each has only one fourth the kinetic energy. The total kinetic energy is half what it would be for a single electron moving around a heavy nucleus.
(positronium)
Shortcomings
The Bohr model gives an incorrect value for the ground state orbital angular momentum. The angular momentum in the true ground state is known to be zero. Although mental pictures fail somewhat at these levels of scale, an electron in the lowest modern "orbital" with no orbital momentum, may be thought of as not to rotate "around" the nucleus at all, but merely to go tightly around it in an ellipse with zero area (this may be pictured as "back and forth", without striking or interacting with the nucleus). This is only reproduced in a more sophisticated semiclassical treatment like Sommerfeld's. Still, even the most sophisticated semiclassical model fails to explain the fact that the lowest energy state is spherically symmetric--- it doesn't point in any particular direction.
In modern quantum mechanics, the electron in hydrogen is a spherical cloud of probability which grows denser near the nucleus. The rate-constant of probability-decay in hydrogen is equal to the inverse of the Bohr radius, but since Bohr worked with circular orbits, not zero area ellipses, the fact that these two numbers exactly agree, is considered a "coincidence." (Though many such coincidental agreements are found between the semi-classical vs. full quantum mechanical treatment of the atom; these include identical energy levels in the hydrogen atom, and the derivation of a fine structure constant, which arises from the relativistic Bohr-Sommerfield model (see below), and which happens to be equal to an entirely different concept, in full modern quantum mechanics).
The Bohr model also has difficulty with, or else fails to explain:
• Much of the spectra of larger atoms. At best, it can make predictions about the K-alpha and some L-alpha X-ray emission spectra for larger atoms, if two additional ad hoc assumptions are made (see Moseley's law above). Emission spectra for atoms with a single outer-shell electron (atoms in the lithium group) can also be approximately predicted. Also, if the empiric electron-nuclear screening factors for many atoms are known, many other spectral lines can be deduced from the information, in similar atoms of differing elements, via the Ritz-Rydberg combination principles (see Rydberg formula). All these techniques essentially make use of Bohr's Newtonian energy-potential picture of the atom.
• The theory does not predict the relative intensities of spectral lines; although in some simple cases, Bohr's formula or modifications of it, was able to provide reasonable estimates (for example, calculations by Kramers for the Stark effect).
• The existence of fine structure and hyperfine structure in spectral lines, which are known to be due to a variety of relativistic and subtle effects, as well as complications from electron spin.
• The Zeeman effect - changes in spectral lines due to external magnetic fields; these are also due to more complicated quantum principles interacting with electron spin and orbital magnetic fields.
• The model also violates the uncertainty principle in that it considers electrons to have known orbits and definite radius, two things which can not be directly known at once.
REFERENCE
www.about.com
www.wikipedia.com
www.physicstoday.com
Encarta encyclopedia
Modern Physics- Arthurbeizer
water mediated organic reactions
Table Of Contents
• Introduction
• Oxidations
• Dehydrogenation, Hydrogenation, Halogenation and Dehalogenation
• Allylations
• Coupling of Acyl Chlorides and Alkynes
• Heck Reaction
• Wittig Reaction
• Mannich-type Reactions
• Intramolecular Diels-Alder Reaction
• Deprotection of functional groups
Organic Synthesis in Water
Water plays an essential role in life processes, however its use as a solvent has been limited in organic synthesis. Despite the fact that it is the cheapest, safest and most non toxic solvent in the world, its presence is generally avoided through the dehydrative drying of substrates and solvents. The use of water as a medium for organic reactions is therefore one of the latest challenges for modern organic chemists. The present Highlight presents a brief selection of different organic reactions run in an aqueous medium from the literature of the past two yearsVolatile organic solvents are the normal media used in both research scale and industrial scale synthesis of organic chemicals. Their environmental impact is significant, however, and so the development of alternative reaction media has become of great interest.
Developments in the use of water as a solvent for organic synthesis have reached the point where it could now be considered a viable solvent for many organic reactions. Organic Reactions in Water demonstrates the underlying principles of using water as a reaction solvent and, by reference to a range of reaction types and systems, it 's effective use in synthetic organic chemistry. Written by an internationally respected team of contributors, and with a strong focus on the practical use of water as a reaction medium, this book illustrates the enormous potential of water for the development of new and unique chemistries and synthetic strategies, while at the same time offering a much reduced environmental impact. .
1. Oxidations
Rao and co-workers report a new methodology for a high yielding (90-96%) chemoselective oxidation of sulphides to sulphoxides using β-cyclodextrin and N-bromosuccinimide (NBS), at room temperature, and under neutral conditions. Chemoselectivity (no overoxidation to sulphones) is explained by the formation of reversible host-guest complexes between the sulphoxide and catalytic amounts of β-cyclodextrin (Tetrahedron Lett. 2005, 46, 4581. DOI:
Using a chemoenzymic oxidation methodology, Tong and co-workers successfully epoxidised water-soluble (81-93% yield) and lipophilic alkenes (60-99% yield). Commercial Glucose Oxidase (GOx) is used to produce in situ hydrogen peroxide via the enzymic oxidation of glucose. The addition of catalytic amounts of sodium bicarbonate/manganese sulphate increases the rate and the yield of the process. In the case of lipophilic alkenes, sodium dodecyl sulphate (SDS) was used as a surfactant
a) water-soluble alkenes: Glucose (0.2 M), GOx (175 units/mL), O2, NaHCO3 (0.5 M), MnSO4 (0.1 mol%), pH 7.0 phosphate sol.; b) water-insoluble soluble alkenes: same conditions plus SDS (5 mM).
A highly efficient (88-98% yield) aerobic oxidation of benzylic alcohols, to the corresponding aldehydes or ketones, was developed by Hu and co-workers. This is a TEMPO (1)-catalysed system using DBDMH (2) and NaNO2 as co-catalysts
2. Dehydrogenation, Hydrogenation, Halogenation and Dehalogenation
Savelli and co-workers developed a mild, high yielding (90%) protocol for the dehydrogenation of primary amines to nitriles using NiSO4 as catalyst and K2S2O8 as oxidant (a stable, cheap and easy to handle salt) in an aqueous surfactant solution of dimethyldodecylamine N-oxide (DDAO) (Eur. J. Org. Chem. 2005, 3060.
An asymmetric transfer hydrogenation of aromatic ketones using the Noyori-Ikariya Ru-Tsdpen catalyst (3) is now reported by Xiao and co-workers. The reaction proceeds with high yield (99%) and enantioselection (85-97% ee) using an aqueous solution of formic acid and Et3N, in which the amine acts as a pH modulator (pH 5-8). The catalyst was recycled more than 10 times without loss in enantioselectivity
a) ketone (1 mmol), 3 (0.012 mmol), H2O (0.5 mL), Et3N (2.7 mmol), HCO2H (3.3 mmol), 40ºC.
Nano-palladium particles (ARP-Pd) supported on an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin was found to effect the hydrogenation of styrene and cinnamic derivatives in high yield (81-99% yield). Uozumi and co-workers found also that this catalytic system can be used in the hydrodechlorination of chloroarenes (81-99% yield), providing a recyclable, clean and safe protocol for the detoxification of aqueous pollutants
Stavber and co-workers used Selectfluor® (4), a commercial, stable and water-soluble fluorinating reagent, for the selective synthesis of a series of vicinal fluorohydrins 5 (from phenyl substituted alkenes, 84-86% yield), α-fluoroketones 6 (from ketones, 85-90% yield) and 7 (from 1,3-diketones or β-ketoesters, 87-91% yield) and fluorodienones 8 and 9 (from phenols, 74-78% yield
Reaction conditions: substrate (1.05-2.1 mmol), 4 (1.1 mmol), H2O/surfactant (5 mL, 0.05%), 60 ºC, 2-24 h.
3. Allylations
Using a recyclable electrochemical process (up to five cycles with excellent yield), Zhang and co-workers developed a tin-mediated protocol for the allylation of aldehydes (95-100% yield).
a) graphite electrode (2.0 V), aldehyde (5 mmol), allyl bromide (8 mmol), SnCl2 (10 mmol), H2O (10 mL), r.t., 6-10 h.
4. Coupling of Acyl Chlorides and Alkynes
Ynones are obtained in high yields (51-99%) by coupling acyl chlorides and alkynes in a new catalytic system, reported by Liu and co-workers, which uses palladium, copper and a surfactant (sodium lauryl sulfate) in a basic aqueous medium
a) acyl chloride (2 mmol), alkyne (1 mmol), PdCl2(PPh3)2 (2 mmol%), CuI (5 mmol%), K2CO3 (3 mmol), surfactant (7 mol%), H2O (1 mL), 65ºC, 4 h.
5. Heck Reaction
Regioselective diarylation (75-92% yield) and monoarylation of unsubstituted (69-96% yield) and substituted (42-91% yield, E/Z 70/30-100/0) α,β-unsaturated carbonyl compounds with aryl iodides is reported by Nájera and Botella. Best results were obtained using the oxime-derived carbapalladacycle catalyst 9 and Cy2NMe as a base
a) ArI (2 mmol), alkene (3 mmol), Cy2NMe (3 mmol), 9 (0.02-1 mol% Pd), H2O (3 mL), 120 ºC, pressure tube, 3-23 h; b) ArI (1 mmol), alkene (1.5 mmol), Cy2NMe (1.5 mmol), 9 (0.1-1 mol% Pd), H2O (2 mL) 120 ºC, pressure tube, 7-38 h; c) ArI (1 mmol), alkene (0.5 mmol), Cy2NMe (1.5 mmol), 9 (0.1-1 mol% Pd), H2O (2 mL), 120 ºC, pressure tube, 8-22 h. Cy= cyclohexyl.
6. Wittig Reaction
Bergdahl and co-workers published the first report in the literature describing that Wittig reactions of stabilised (and poorly water-soluble) ylides with aldehydes are unexpectedly accelerated in an aqueous media).
a) aldehyde (1 mmol), ylide (1.2-1.5 mmol), H2O (5 mL), 20-90 ºC, 5 min - 4 h. Troc= 2,2,2-trichloroethoxycarbonyl.
7. Mannich-type Reactions
Following an early report, Kobayashi and co-workers published an efficient (up to 94% yield) enantio- and diastereoselective (syn/anti 8-92 to 92-8, 67-95% ee) protocol for Mannich-type reactions of a hydrazono ester with silicon enolates in aqueous medium. One example of a syn adduct from an (E)-silicon enolate and two examples of anti adducts from (Z)-silicon enolates are
a) acyl hydrazono ester (0.4 mmol), silyl enol ether (1.2 mmol), ZnF2 (100 mol%), 10 (10 mol%), CTAB (0.02 mmol), H2O (1.95 mL), 0 ºC, 20 h. CTAB= cetyltrimethylammonium bromide.
8. Intramolecular Diels-Alder Reaction
Taguchi and co-workers demonstrated that the intramolecular Diels-Alder reaction of 1,7,9-decatrienoate derivatives can be performed in an aqueous medium (H2O-iPrOH 6:1) using indium(III) triflate as a recyclable catalyst (3 runs reported without loss in yield) to give the corresponding endo cycloadducts in good yield (up to 83%)
a) alkene (0.5 mmol), In(OTf)3 (20 mmol%), H2O (6 mL), iPrOH (1 mL), 70-80ºC, 8-24 h.
9. Deprotection of Functional Groups
Methods for selective deprotection of functional groups are key tools for organic chemists. The following examples, performed in water, open new possibilities for the use of this challenging medium.
9.1 Acetates, Alkyl Ethers and Acetals
Deprotection of several acetates, alkyl ethers and acetals in aqueous media were recently reviewed and are summarized in Table 1.
reported a simple protocol for the deprotections of oximes and imines under neutral conditions (yields up to 90%) using a I2/surfactant/water system.
a) oxime or imine (1 mmol), I2 (20 mmol%), H2O (15 mL), SDS (0.2 mmol), 25-40°C, 3.5-8 h.
• Introduction
• Oxidations
• Dehydrogenation, Hydrogenation, Halogenation and Dehalogenation
• Allylations
• Coupling of Acyl Chlorides and Alkynes
• Heck Reaction
• Wittig Reaction
• Mannich-type Reactions
• Intramolecular Diels-Alder Reaction
• Deprotection of functional groups
Organic Synthesis in Water
Water plays an essential role in life processes, however its use as a solvent has been limited in organic synthesis. Despite the fact that it is the cheapest, safest and most non toxic solvent in the world, its presence is generally avoided through the dehydrative drying of substrates and solvents. The use of water as a medium for organic reactions is therefore one of the latest challenges for modern organic chemists. The present Highlight presents a brief selection of different organic reactions run in an aqueous medium from the literature of the past two yearsVolatile organic solvents are the normal media used in both research scale and industrial scale synthesis of organic chemicals. Their environmental impact is significant, however, and so the development of alternative reaction media has become of great interest.
Developments in the use of water as a solvent for organic synthesis have reached the point where it could now be considered a viable solvent for many organic reactions. Organic Reactions in Water demonstrates the underlying principles of using water as a reaction solvent and, by reference to a range of reaction types and systems, it 's effective use in synthetic organic chemistry. Written by an internationally respected team of contributors, and with a strong focus on the practical use of water as a reaction medium, this book illustrates the enormous potential of water for the development of new and unique chemistries and synthetic strategies, while at the same time offering a much reduced environmental impact. .
1. Oxidations
Rao and co-workers report a new methodology for a high yielding (90-96%) chemoselective oxidation of sulphides to sulphoxides using β-cyclodextrin and N-bromosuccinimide (NBS), at room temperature, and under neutral conditions. Chemoselectivity (no overoxidation to sulphones) is explained by the formation of reversible host-guest complexes between the sulphoxide and catalytic amounts of β-cyclodextrin (Tetrahedron Lett. 2005, 46, 4581. DOI:
Using a chemoenzymic oxidation methodology, Tong and co-workers successfully epoxidised water-soluble (81-93% yield) and lipophilic alkenes (60-99% yield). Commercial Glucose Oxidase (GOx) is used to produce in situ hydrogen peroxide via the enzymic oxidation of glucose. The addition of catalytic amounts of sodium bicarbonate/manganese sulphate increases the rate and the yield of the process. In the case of lipophilic alkenes, sodium dodecyl sulphate (SDS) was used as a surfactant
a) water-soluble alkenes: Glucose (0.2 M), GOx (175 units/mL), O2, NaHCO3 (0.5 M), MnSO4 (0.1 mol%), pH 7.0 phosphate sol.; b) water-insoluble soluble alkenes: same conditions plus SDS (5 mM).
A highly efficient (88-98% yield) aerobic oxidation of benzylic alcohols, to the corresponding aldehydes or ketones, was developed by Hu and co-workers. This is a TEMPO (1)-catalysed system using DBDMH (2) and NaNO2 as co-catalysts
2. Dehydrogenation, Hydrogenation, Halogenation and Dehalogenation
Savelli and co-workers developed a mild, high yielding (90%) protocol for the dehydrogenation of primary amines to nitriles using NiSO4 as catalyst and K2S2O8 as oxidant (a stable, cheap and easy to handle salt) in an aqueous surfactant solution of dimethyldodecylamine N-oxide (DDAO) (Eur. J. Org. Chem. 2005, 3060.
An asymmetric transfer hydrogenation of aromatic ketones using the Noyori-Ikariya Ru-Tsdpen catalyst (3) is now reported by Xiao and co-workers. The reaction proceeds with high yield (99%) and enantioselection (85-97% ee) using an aqueous solution of formic acid and Et3N, in which the amine acts as a pH modulator (pH 5-8). The catalyst was recycled more than 10 times without loss in enantioselectivity
a) ketone (1 mmol), 3 (0.012 mmol), H2O (0.5 mL), Et3N (2.7 mmol), HCO2H (3.3 mmol), 40ºC.
Nano-palladium particles (ARP-Pd) supported on an amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin was found to effect the hydrogenation of styrene and cinnamic derivatives in high yield (81-99% yield). Uozumi and co-workers found also that this catalytic system can be used in the hydrodechlorination of chloroarenes (81-99% yield), providing a recyclable, clean and safe protocol for the detoxification of aqueous pollutants
Stavber and co-workers used Selectfluor® (4), a commercial, stable and water-soluble fluorinating reagent, for the selective synthesis of a series of vicinal fluorohydrins 5 (from phenyl substituted alkenes, 84-86% yield), α-fluoroketones 6 (from ketones, 85-90% yield) and 7 (from 1,3-diketones or β-ketoesters, 87-91% yield) and fluorodienones 8 and 9 (from phenols, 74-78% yield
Reaction conditions: substrate (1.05-2.1 mmol), 4 (1.1 mmol), H2O/surfactant (5 mL, 0.05%), 60 ºC, 2-24 h.
3. Allylations
Using a recyclable electrochemical process (up to five cycles with excellent yield), Zhang and co-workers developed a tin-mediated protocol for the allylation of aldehydes (95-100% yield).
a) graphite electrode (2.0 V), aldehyde (5 mmol), allyl bromide (8 mmol), SnCl2 (10 mmol), H2O (10 mL), r.t., 6-10 h.
4. Coupling of Acyl Chlorides and Alkynes
Ynones are obtained in high yields (51-99%) by coupling acyl chlorides and alkynes in a new catalytic system, reported by Liu and co-workers, which uses palladium, copper and a surfactant (sodium lauryl sulfate) in a basic aqueous medium
a) acyl chloride (2 mmol), alkyne (1 mmol), PdCl2(PPh3)2 (2 mmol%), CuI (5 mmol%), K2CO3 (3 mmol), surfactant (7 mol%), H2O (1 mL), 65ºC, 4 h.
5. Heck Reaction
Regioselective diarylation (75-92% yield) and monoarylation of unsubstituted (69-96% yield) and substituted (42-91% yield, E/Z 70/30-100/0) α,β-unsaturated carbonyl compounds with aryl iodides is reported by Nájera and Botella. Best results were obtained using the oxime-derived carbapalladacycle catalyst 9 and Cy2NMe as a base
a) ArI (2 mmol), alkene (3 mmol), Cy2NMe (3 mmol), 9 (0.02-1 mol% Pd), H2O (3 mL), 120 ºC, pressure tube, 3-23 h; b) ArI (1 mmol), alkene (1.5 mmol), Cy2NMe (1.5 mmol), 9 (0.1-1 mol% Pd), H2O (2 mL) 120 ºC, pressure tube, 7-38 h; c) ArI (1 mmol), alkene (0.5 mmol), Cy2NMe (1.5 mmol), 9 (0.1-1 mol% Pd), H2O (2 mL), 120 ºC, pressure tube, 8-22 h. Cy= cyclohexyl.
6. Wittig Reaction
Bergdahl and co-workers published the first report in the literature describing that Wittig reactions of stabilised (and poorly water-soluble) ylides with aldehydes are unexpectedly accelerated in an aqueous media).
a) aldehyde (1 mmol), ylide (1.2-1.5 mmol), H2O (5 mL), 20-90 ºC, 5 min - 4 h. Troc= 2,2,2-trichloroethoxycarbonyl.
7. Mannich-type Reactions
Following an early report, Kobayashi and co-workers published an efficient (up to 94% yield) enantio- and diastereoselective (syn/anti 8-92 to 92-8, 67-95% ee) protocol for Mannich-type reactions of a hydrazono ester with silicon enolates in aqueous medium. One example of a syn adduct from an (E)-silicon enolate and two examples of anti adducts from (Z)-silicon enolates are
a) acyl hydrazono ester (0.4 mmol), silyl enol ether (1.2 mmol), ZnF2 (100 mol%), 10 (10 mol%), CTAB (0.02 mmol), H2O (1.95 mL), 0 ºC, 20 h. CTAB= cetyltrimethylammonium bromide.
8. Intramolecular Diels-Alder Reaction
Taguchi and co-workers demonstrated that the intramolecular Diels-Alder reaction of 1,7,9-decatrienoate derivatives can be performed in an aqueous medium (H2O-iPrOH 6:1) using indium(III) triflate as a recyclable catalyst (3 runs reported without loss in yield) to give the corresponding endo cycloadducts in good yield (up to 83%)
a) alkene (0.5 mmol), In(OTf)3 (20 mmol%), H2O (6 mL), iPrOH (1 mL), 70-80ºC, 8-24 h.
9. Deprotection of Functional Groups
Methods for selective deprotection of functional groups are key tools for organic chemists. The following examples, performed in water, open new possibilities for the use of this challenging medium.
9.1 Acetates, Alkyl Ethers and Acetals
Deprotection of several acetates, alkyl ethers and acetals in aqueous media were recently reviewed and are summarized in Table 1.
reported a simple protocol for the deprotections of oximes and imines under neutral conditions (yields up to 90%) using a I2/surfactant/water system.
a) oxime or imine (1 mmol), I2 (20 mmol%), H2O (15 mL), SDS (0.2 mmol), 25-40°C, 3.5-8 h.
text editors in linux both cli and gui
INTRODUCTION
The first text editors were line editors oriented on typewriter style terminals and they did not provide a window or screen-oriented display. They usually had very short commands (to minimize typing) that reproduced the current line. Among them were a command to print a selected section(s) of the file on the typewriter (or printer) in case of necessity. An "edit cursor", an imaginary insertion point, could be moved by special commands that operated with line numbers of specific text strings (context). Later, the context strings were extended to regular expressions. To see the changes, the file needed to be printed on the printer. These "line-based text editors" were considered revolutionary improvements over keypunch machines. In case typewriter-based terminals were not available, they were adapted to keypunch equipment. In this case the user needed to punch the commands into the separate deck of cards and feed them into the computer in order to edit the file.
When computer terminals with video screens became available, screen-based text editors became common. One of the earliest "full screen" editors was O26 - which was written for the operator console of the CDC 6000 series machines in 1967. Another early full screen editor is vi. Written in the 1970s, vi is still a standard editor for Unix and Linux operating systems. The productivity of editing using full-screen editors (compared to the line-based editors) motivated many of the early purchases of video terminals. Some text editors are small and simple, while others offer a broad and complex range of functionality. For example, Unix and Unix-like operating systems have the vi editor (or a variant), but many also include the Emacs editor. Microsoft Windows systems come with the very simple Notepad, though many people—especially programmers—prefer to use one of many other Windows text editors with more features. Under Apple Macintosh's classic Mac OS there was the native SimpleText, which was replaced by TextEdit. Some editors, such as WordStar, have dual operating modes allowing them to be either a text editor or a word processor.
Text editors geared for professional computer users place no limit on the size of the file being opened. In particular, they start quickly even when editing large files, and are capable of editing files that are too large to fit the computer's main memory. Simpler text editors often just read files into an array in RAM. On larger files this is a slow process, and very large files often do not fit.
The ability to read and write very large files is needed by many professional computer users. For example, system administrators may need to read long log files. Programmers may need to change large source code files, or examine unusually large texts, such as an entire dictionary placed in a single file
VI Editor
The VI editor is a screen-based editor used by many Unix users. The VI editor has powerful features to aid programmers, but many beginning users avoid using VI because the different features overwhelm them. This tutorial is written to help beginning users get accustomed to using the VI editor, but also contains sections relevant to regular users of VI as well. Examples are provided, and the best way to learn is to try these examples, and think of your
.
Starting the VI Editor
The VI editor lets a user create new files or edit existing files. The command to start the VI editor is vi, followed by the filename. For example to edit a file called temporary, you would type vi temporary and then return. You can start VI without a filename, but when you want to save your work, you will have to tell VI which filename to save it into later.
When you start VI for the first time, you will see a screen filled with tildes (A tilde looks like this: ~) on the left side of the screen. Any blank lines beyond the end of the file are shown this way. At the bottom of your screen, the filename should be shown, if you specified an existing file, and the size of the file will be shown as well, like this:
"filename" 21 lines, 385 characters
If the file you specified does not exist, then it will tell you that it is a new file, like this:
"newfile" [New file]
If you started VI without a filename, the bottom line of the screen will just be blank when VI starts. If the screen does not show you these expected results, your terminal type may be set wrong. Just type :q and return to get out of VI, and fix your terminal type. If you don't know how, ask a lab monitor.
Getting Out of VI
Now that you know how to get into VI, it would be a good idea to know how to get out of it. The VI editor has two modes and in order to get out of VI, you have to be in command mode. Hit the key labeled "Escape" or "Esc" (If your terminal does not have such a key, then try ^[, or control-[.) to get into command mode. If you were already in the command mode when you hit "Escape", don't worry. It might beep, but you will still be in the command mode.
The command to quit out of VI is :q. Once in command mode, type colon, and 'q', followed by return. If your file has been modified in any way, the editor will warn you of this, and not let you quit. To ignore this message, the command to quit out of VI without saving is :q!. This lets you exit VI without saving any of the changes.
Of course, normally in an editor, you would want to save the changes you have made. The command to save the contents of the editor is :w. You can combine the above command with the quit command, or :wq. You can specify a different file name to save to by specifying the name after the :w. For example, if you wanted to save the file you were working as another filename called filename2, you would type: w filename2 and return.
Another way to save your changes and exit out of VI is the ZZ command. When in command mode, type ZZ and it will do the equivalent of :wq. If any changes were made to the file, it will be saved. This is the easiest way to leave the editor, with only two keystrokes.
The Two Modes of VI
The first thing most users learn about the VI editor is that it has two modes: command and insert. The command mode allows the entry of commands to manipulate text. These commands are usually one or two characters long, and can be entered with few keystrokes. The insert mode puts anything typed on the keyboard into the current file.
VI starts out in command mode. There are several commands that put the VI editor into insert mode. The most commonly used commands to get into insert mode are a and i. These two commands are described below. Once you are in insert mode, you get out of it by hitting the escape key. If your terminal does not have an escape key, ^[ should work (control-[). You can hit escape two times in a row and VI would definitely be in command mode. Hitting escape while you are already in command mode doesn't take the editor out of command mode. It may beep to tell you that you are already in that mode.
How to Type Commands in Command Mode
The command mode commands are normally in this format: (Optional arguments are given in the brackets)
[count] command [where]
Most commands are one character long, including those which use control characters. The commands described in this section are those which are used most commonly the VI editor.
The count is entered as a number beginning with any character from 1 to 9. For example, the x command deletes a character under the cursor. If you type 23x while in command mode, it will delete 23 characters.
Some commands use an optional where parameter, where you can specify how many lines or how much of the document the command affects, the where parameter can also be any command that moves the cursor.
Some Simple VI Commands
Here is a simple set of commands to get a beginning VI user started. There are many other convenient commands, which will be discussed in later sections.
a
enter insert mode, the characters typed in will be inserted after the current cursor position. If you specify a count, all the text that had been inserted will be repeated that many times.
h
move the cursor to the left one character position.
i
enter insert mode, the characters typed in will be inserted before the current cursor position. If you specify a count, all the text that had been inserted will be repeated that many times.
j
move the cursor down one line.
k
move the cursor up one line.
l
move the cursor to the right one character position.
r
replace one character under the cursor. Specify count to replace a number of characters
u
undo the last change to the file. Typing u again will re-do the change.
x
delete character under the cursor. Count specifies how many characters to delete. The characters will be deleted after the cursor.
Cutting and Yanking
The command commonly used command for cutting is d. This command deletes text from the file. The command is preceded by an optional count and followed by a movement specification. If you double the command by typing dd, it deletes the current line. Here are some combinations of these:
d^
deletes from current cursor position to the beginning of the line.
d$
deletes from current cursor position to the end of the line.
dw
deletes from current cursor position to the end of the word.
3dd
deletes three lines from current cursor position downwards.
There is also the y command which operates similarly to the d command which take text from the file without deleting the text.
Pasting
The commands to paste are p and P. The only differ in the position relative to the cursor where they paste. p pastes the specified or general buffer after the cursor position, while P pastes the specified or general buffer before the cursor position. Specifying count before the paste command pastes text the specified number of times.
Indenting Your Code and Checking
The VI editor has features to help programmers format their code neatly. There is a variable that to set up the indentation for each level of nesting in code. In order to set it up, see the customization section of this tutorial. For example, the command to set the shift width to 4 characters is :set sw=4.
The following commands indent your lines or remove the indentation, and can be specified with count:
<<
Shifts the current line to the left by one shift width.
>>
Shifts the current line to the right by one shift width.
The VI editor also has a helpful feature which checks your source code for any hanging parentheses or braces. The % command will look for the left parenthesis or brace corresponding to a particular right parenthesis or brace and vice versa. Place the cursor onto a parenthesis or brace and type % to move the cursor to the corresponding parenthesis or brace. This is useful to check for unclosed parentheses or braces. If a parenthesis or brace exists without a matching parenthesis or brace, VI will beep at you to indicate that no matching symbol was found.
Word and Character Searching
The VI editor has two kinds of searches: string and character. For a string search, the / and ? commands are used. When you start these commands, the command just typed will be shown on the bottom line, where you type the particular string to look for. These two commands differ only in the direction where the search takes place. The / command searches forwards (downwards) in the file, while the ? command searches backwards (upwards) in the file. The n and N commands repeat the previous search command in the same or opposite direction, respectively. Some characters have special meanings to VI, so they must be preceded by a backslash (\) to be included as part of the search expression.
Emacs Editor
Emacs is another editor available in UNIX. Like vi, emacs is a screen editor. Unlike vi, emacs is not an insertion mode editor, meaning that any character typed in emacs is automatically inserted into the file, unless it includes a command prefix.
Commands in emacs are either control characters (hold down the key while typing another character) or are prefixed by one of a set of reserved characters: or -X. The key can be typed by itself (because it really is a character) and then followed by another character; the key must be held down while the next character is being typed. The conventions for describing these characters (since it takes too long to type out the whole thing) are ESC means and C- means .
One other distinction between emacs and vi is that emacs allows you to edit several files at once. The window for emacs can be divided into several windows, each of which contains a view into a buffer. Each buffer typically corresponds to a different file. Many of the commands listed below are for reading files into new buffers and moving between buffers.
To use emacs on a file, type
emacs filename
If the file named filename exists, then the first screen's worth of the file is displayed; if it doesn't exist, a help message is displayed.
The easiest way to learn emacs is to start it up and go through the on-line tutorial. To access the on-line tutorial, type
ESC help-with-tutorial
immediately after you have started emacs. The tutorial directs you further in learning the basic commands. One notational point you should know is that the tutorial uses M- to mean ESC.
* C-h help-command: first character in lots of useful help commands
* C-h t help-with-tutorial: command to run the tutorial
C-h i information: describes most of the emacs commands in man style pages
C-h k describe-key: tells you what a particular key stroke does
* C-h a command-apropos: prompts for a string and
then searches for all emacs commands that contains that string
ESC ? also does command-apropos
* C-h ? help-for-help: describes how to use the help facilities
To give you a head start, the following table lists the basic commands you need to know to use emacs to edit a file. An asterisk (* or star) to the left of a command indicate it is one to learn immediately.
________________________________________
Help Commands
File Reading and Writing Commands
* C-x C-f find-file: first prompts for a filename and
then loads that file into a editor buffer of the same name
* C-x C-s save-buffer: saves the buffer into the associated filename
C-x C-w write-named-file: prompts for a new filename and writes the buffer into it
Cursor/Screen Movement Commands
Depending on the terminal, some of the cursor movement can be handled by the arrow keys.
* C-a move cursor to (at) beginning-of-line
C-e move cursor to end-of-line
* C-f move cursor forward one character
* C-b move cursor backward one character
* C-n move cursor to next line
* C-p move cursor to previous line
C-v scroll file forward by one screenful
ESC v scroll file backward by one screenful
* ESC < go to beginning-of-buffer
* ESC > go to end-of-buffer
ESC f move cursor forward one word
ESC b move cursor backward one word
Copy and Delete Commands
C-d delete-char: delete character under cursor
ESC d delete-word: delete from cursor to end of word immediately ahead of the cursor
* C-k kill-line: delete the rest of the current line
* C-@ set-mark-command: mark is used to indicate the beginning of an area of text to be yanked
* C-w kill-region: delete the area of text between the mark and the current cursor position
* C-y yank: insert at current cursor location whatever was most recently deleted
ESC w copy-region-as-kill: copy area between mark and cursor into kill-buffer
so that it can be yanked into someplace else
Search Commands
* C-s isearch-forward: prompts for text string and
then searches from the current cursor position forwards in the buffer
C-r isearch-backward: like isearch-forward,
but searches from the current cursor position to end of buffer for text string
ESC % query-replace: prompts for a search string and
a string with which to replace the search string
Window and Buffer Commands
C-x 0 zero-window: deletes current window
C-x 2 double-window: splits current window into two parts,
allowing you to edit at two different locations in the same file
or permitting you to view two different files at the same time
C-x b switch-to-buffer: display a different buffer on the screen
C-x o other-window: move the cursor to the other window
(assuming that you have two windows/buffers open at once
* C-x C-b list-buffers: lists those buffers currently loaded into emacs
Exiting Emacs, Fixing Mistakes and Other Important Stuff
* C-x C-c save-buffers-kill-emacs: when you are finished editing,
to save the edited but unsaved buffers
and to return you to the UNIX prompt
* C-g keyboard-quit: if while typing a command you make a mistake and want to stop,
this aborts a command in progress
C-u universal-argument: if you want to do a command several times,
type this command
followed by a number (for the number of times)
followed by the command you wish repeated
* C-x u undo: undoes the last command typed, in case you made a mistake
* ESC x execute-extended-command: prompts for the name of an emacs command;
allows you to execute a command
if you know roughly what it is called
but cannot remember the key strokes for it
________________________________________
Joe's Own Editor
JOE is a full featured terminal-based screen editor which is distributed under the GNU General Public License (GPL). JOE has been around since 1988 and comes standard with many Linux distributions.
JOE is being maintained by its original author Joseph Allen, plus all of the people who send bug reports, feature suggestions and patches to the project web site. JOE is hosted by SourceForge.net and its source code is controlled under CVS. Over the last few years there has been about one major new release a year, usually in the April-May timeframe.
JOE is a blending of MicroPro's venerable microcomputer word processor WordStar and Richard Stallman's famous LISP based text editor GNU-EMACS (but it does not use code from either program): most of the basic editing keys are the same as in WordStar as is the overall feel of the editor. JOE also has some of the key bindings and many of the powerful features of EMACS.
JOE is written in C and its only dependency is libc. This makes JOE very easy to build (just "configure" and "make install"), making it feasible to include on small systems and recovery disks. The compiled binary is about 300K in x86. Note that JOE can use either the termcap or terminfo terminal capabilities databases (or a built-in termcap entry for ANSI terminals). The choice is controlled by a "configure" option. If terminfo is used, a library is required to access the database (on some systems this library is ncurses, but JOE does not use curses to control the terminal- it has its own code for this).
Much of the look and feel of JOE is determined by its simple configuration file "joerc". Several variants of the editor are installed by default in addition to "joe": "jmacs" (emulate GNU-EMACS), "jstar" emulate WordStar, "jpico" emulate the Pine mailer editor PICO and "rjoe"- a restricted version of JOE which allows the used to only edit the file given on the command line. JOE is linked to several names. The name which is used to invoke the editor with "rc" tacked on the end gives the name of configuration file to use. It is thus easy for you to make your own variant if you want. Also you can customize the editor by copying the system "joerc" file to your home directory.
Here is a basic screen shot of JOE running in a Cygwin console:
Here is a screen shot showing several windows- the first has some example double-wide characters, the second is the same buffer as the first, but in hex-dump view mode, the third is a shell window and the fourth shows a selected rectangular block of numbers and their sum:
JOE has the following features:
• Multi-file search and replace- file list is either given on command line or by a UNIX command (grep/find) run from within JOE.
• Mouse support, including wheel (works best when using xterm). The mouse can resize windows, scroll windows, select and paste text, and select menu entries.
• Context display on status line: allows you to see name of function cursor is in.
• UTF-8 support, optional auto-detect of UTF-8 files.
• Syntax highlighting for more than 40 languages.
• Hexadecimal edit mode. Use JOE as a disk editor: joe -overwrite -hex /dev/hda1,0,512 (edit first sector of /dev/hda1).
• Non-destructive editing of binary files even when handling MS-DOS or UNIX line endings.
• Swap file allows editing files larger than memory.
• Context sensitive on-line help.
• Bash-like TAB completion and history for all prompts, or jump into the completion menu and use it to traverse the file system.
• Complete word in edit buffer by hitting ESC Enter (uses other words in buffer for dictionary).
• EMACS-compatible file locks and file modification checking.
• Shell windows.
• Multiple-windows onto same or different files.
• Compile and step through errors or Grep and step through finds.
• Goto matching character delimiter ( [ { < which skips comments and quoted matter.
• Goto matching word delimiter, including XML tags and C preprocessor directives.
• Ctrl-arrow key block selection.
• Search and replace system, including regular expression and optional incremental search. Regular expression key for matching balanced C expressions.
• Tags file search (tab completion at tags search prompt uses tags file as database).
• Spell check commands which invoke aspell or ispell. Language for aspell can be passed through editor.
• Paragraph format which preserves news/mail quoting indentation characters.
• Unlimited Undo and Redo.
• Yank buffer allows stepping through and insertion of previously deleted text.
• State file restores history buffers, yank buffer and last file cursor positions.
• Cursor position history allows you to step through previously visited areas of a file.
• Multiple interactive keyboard macros. Macros can be assigned to key sequences in joerc file.
• Block move/copy/delete/filter.
• Rectangle (columnar) block mode- search and replace can be narrowed to the rectangular block. Rectangular blocks can be filtered through UNIX commands.
• Overtype/Insert modes.
• Indent/Unindent (shift block left or right).
• Auto-indent mode.
• Picture mode for ASCII graphics.
• Line number mode displays line number of each line.
• Powerful scientific calculator with block statistics functions (sum/standard-deviation/count highlighted block of numbers).
• Termcap/Terminfo support allows JOE to use any terminal or terminal emulator.
• Can accept data from a pipe, for example: ls | joe
GEDIT
gedit is the official text editor of the GNOME desktop environment.
While aiming at simplicity and ease of use, gedit is a powerful general purpose text editor.
Currently it features:
• Full support for internationalized text (UTF-8)
• Configurable syntax highlighting for various languages (C, C++, Java, HTML, XML, Python, Perl and many others)
• Undo/Redo
• Editing files from remote locations
• File reverting
• Print and print preview support
• Clipboard support (cut/copy/paste)
• Search and replace
• Go to specific line
• Auto indentation
• Text wrapping
• Line numbers
• Right margin
• Current line highlighting
• Bracket matching
• Backup files
• Configurable fonts and colors
• A complete online user manual
gedit features also a flexible plugin system which can be used to dynamically add new advanced features to gedit itself. See the plugins page for more info on the existing plugins.
Go to the screenshots page to see gedit in action!
gedit is released under the GNU General Public License (GPL).
ActiveState Komodo
ActiveState Komodo
Developed by
ActiveState
Stable release
5.1.3 (2009-4-29; 8 days ago) [+/−]
Preview release
none (n/a) [+/−]
Written in
Python, JavaScript, XUL
Operating system
Cross-platform
Available in
English
Type
IDE
License
IDE:Proprietary; Edit: MPL/GPL/LGPL
Website
http://www.activestate.com/komodo/
ActiveState Komodo is the name given to a family of integrated development environment (IDE) applications produced by software firm ActiveState.
•
Komodo IDE
Komodo IDE is an IDE for dynamic programming languages built on the Mozilla platform. It supports dynamic languages, including JavaScript, Perl, PHP, Python, Ruby, and Tcl; framework stacks like Ruby on Rails and CakePHP; and client libraries such as the Yahoo! UI Library and Dojo.
ActiveState added browser-side support in Komodo IDE 4.0, including debugging, DOM viewer, catalog support, HTTP Inspector, and code intelligence for languages such as JavaScript, CSS, HTML, and XML, enabling programmers to edit and debug Ajax code and multi-language files.
Komodo IDE, although not Open Source, is extensible using standard Mozilla APIs based on XUL, XBL, and XPCOM, plus Python and JavaScript.
Komodo IDE is available for Linux, Mac OS X, and Microsoft Windows platforms.
Komodo Edit
Komodo Edit is a free text editor for dynamic programming languages introduced in January 2007. With the release of version 4.3, Komodo Edit is built on top of the Open Komodo project.
Komodo Edit inherits many features of Komodo IDE, like the full range of supported languages (Perl, PHP, Python, Ruby, Tcl) and platforms (Linux, Mac OS X, and Windows ). And like Komodo IDE, Komodo Edit also supports browser-side languages like JavaScript, CSS, HTML, and XML.
It was developed for programmers who need a multi-language editor with broad functionality, but not the features of an IDE, like debugging, DOM viewer, interactive shells, and source code control integration
REFERENCE CITED
www.wikipedia.com
www.linuxforum.com
www.gedit.com
Linux Bible
Encarta encylopedia
Linux prgramming
The first text editors were line editors oriented on typewriter style terminals and they did not provide a window or screen-oriented display. They usually had very short commands (to minimize typing) that reproduced the current line. Among them were a command to print a selected section(s) of the file on the typewriter (or printer) in case of necessity. An "edit cursor", an imaginary insertion point, could be moved by special commands that operated with line numbers of specific text strings (context). Later, the context strings were extended to regular expressions. To see the changes, the file needed to be printed on the printer. These "line-based text editors" were considered revolutionary improvements over keypunch machines. In case typewriter-based terminals were not available, they were adapted to keypunch equipment. In this case the user needed to punch the commands into the separate deck of cards and feed them into the computer in order to edit the file.
When computer terminals with video screens became available, screen-based text editors became common. One of the earliest "full screen" editors was O26 - which was written for the operator console of the CDC 6000 series machines in 1967. Another early full screen editor is vi. Written in the 1970s, vi is still a standard editor for Unix and Linux operating systems. The productivity of editing using full-screen editors (compared to the line-based editors) motivated many of the early purchases of video terminals. Some text editors are small and simple, while others offer a broad and complex range of functionality. For example, Unix and Unix-like operating systems have the vi editor (or a variant), but many also include the Emacs editor. Microsoft Windows systems come with the very simple Notepad, though many people—especially programmers—prefer to use one of many other Windows text editors with more features. Under Apple Macintosh's classic Mac OS there was the native SimpleText, which was replaced by TextEdit. Some editors, such as WordStar, have dual operating modes allowing them to be either a text editor or a word processor.
Text editors geared for professional computer users place no limit on the size of the file being opened. In particular, they start quickly even when editing large files, and are capable of editing files that are too large to fit the computer's main memory. Simpler text editors often just read files into an array in RAM. On larger files this is a slow process, and very large files often do not fit.
The ability to read and write very large files is needed by many professional computer users. For example, system administrators may need to read long log files. Programmers may need to change large source code files, or examine unusually large texts, such as an entire dictionary placed in a single file
VI Editor
The VI editor is a screen-based editor used by many Unix users. The VI editor has powerful features to aid programmers, but many beginning users avoid using VI because the different features overwhelm them. This tutorial is written to help beginning users get accustomed to using the VI editor, but also contains sections relevant to regular users of VI as well. Examples are provided, and the best way to learn is to try these examples, and think of your
.
Starting the VI Editor
The VI editor lets a user create new files or edit existing files. The command to start the VI editor is vi, followed by the filename. For example to edit a file called temporary, you would type vi temporary and then return. You can start VI without a filename, but when you want to save your work, you will have to tell VI which filename to save it into later.
When you start VI for the first time, you will see a screen filled with tildes (A tilde looks like this: ~) on the left side of the screen. Any blank lines beyond the end of the file are shown this way. At the bottom of your screen, the filename should be shown, if you specified an existing file, and the size of the file will be shown as well, like this:
"filename" 21 lines, 385 characters
If the file you specified does not exist, then it will tell you that it is a new file, like this:
"newfile" [New file]
If you started VI without a filename, the bottom line of the screen will just be blank when VI starts. If the screen does not show you these expected results, your terminal type may be set wrong. Just type :q and return to get out of VI, and fix your terminal type. If you don't know how, ask a lab monitor.
Getting Out of VI
Now that you know how to get into VI, it would be a good idea to know how to get out of it. The VI editor has two modes and in order to get out of VI, you have to be in command mode. Hit the key labeled "Escape" or "Esc" (If your terminal does not have such a key, then try ^[, or control-[.) to get into command mode. If you were already in the command mode when you hit "Escape", don't worry. It might beep, but you will still be in the command mode.
The command to quit out of VI is :q. Once in command mode, type colon, and 'q', followed by return. If your file has been modified in any way, the editor will warn you of this, and not let you quit. To ignore this message, the command to quit out of VI without saving is :q!. This lets you exit VI without saving any of the changes.
Of course, normally in an editor, you would want to save the changes you have made. The command to save the contents of the editor is :w. You can combine the above command with the quit command, or :wq. You can specify a different file name to save to by specifying the name after the :w. For example, if you wanted to save the file you were working as another filename called filename2, you would type: w filename2 and return.
Another way to save your changes and exit out of VI is the ZZ command. When in command mode, type ZZ and it will do the equivalent of :wq. If any changes were made to the file, it will be saved. This is the easiest way to leave the editor, with only two keystrokes.
The Two Modes of VI
The first thing most users learn about the VI editor is that it has two modes: command and insert. The command mode allows the entry of commands to manipulate text. These commands are usually one or two characters long, and can be entered with few keystrokes. The insert mode puts anything typed on the keyboard into the current file.
VI starts out in command mode. There are several commands that put the VI editor into insert mode. The most commonly used commands to get into insert mode are a and i. These two commands are described below. Once you are in insert mode, you get out of it by hitting the escape key. If your terminal does not have an escape key, ^[ should work (control-[). You can hit escape two times in a row and VI would definitely be in command mode. Hitting escape while you are already in command mode doesn't take the editor out of command mode. It may beep to tell you that you are already in that mode.
How to Type Commands in Command Mode
The command mode commands are normally in this format: (Optional arguments are given in the brackets)
[count] command [where]
Most commands are one character long, including those which use control characters. The commands described in this section are those which are used most commonly the VI editor.
The count is entered as a number beginning with any character from 1 to 9. For example, the x command deletes a character under the cursor. If you type 23x while in command mode, it will delete 23 characters.
Some commands use an optional where parameter, where you can specify how many lines or how much of the document the command affects, the where parameter can also be any command that moves the cursor.
Some Simple VI Commands
Here is a simple set of commands to get a beginning VI user started. There are many other convenient commands, which will be discussed in later sections.
a
enter insert mode, the characters typed in will be inserted after the current cursor position. If you specify a count, all the text that had been inserted will be repeated that many times.
h
move the cursor to the left one character position.
i
enter insert mode, the characters typed in will be inserted before the current cursor position. If you specify a count, all the text that had been inserted will be repeated that many times.
j
move the cursor down one line.
k
move the cursor up one line.
l
move the cursor to the right one character position.
r
replace one character under the cursor. Specify count to replace a number of characters
u
undo the last change to the file. Typing u again will re-do the change.
x
delete character under the cursor. Count specifies how many characters to delete. The characters will be deleted after the cursor.
Cutting and Yanking
The command commonly used command for cutting is d. This command deletes text from the file. The command is preceded by an optional count and followed by a movement specification. If you double the command by typing dd, it deletes the current line. Here are some combinations of these:
d^
deletes from current cursor position to the beginning of the line.
d$
deletes from current cursor position to the end of the line.
dw
deletes from current cursor position to the end of the word.
3dd
deletes three lines from current cursor position downwards.
There is also the y command which operates similarly to the d command which take text from the file without deleting the text.
Pasting
The commands to paste are p and P. The only differ in the position relative to the cursor where they paste. p pastes the specified or general buffer after the cursor position, while P pastes the specified or general buffer before the cursor position. Specifying count before the paste command pastes text the specified number of times.
Indenting Your Code and Checking
The VI editor has features to help programmers format their code neatly. There is a variable that to set up the indentation for each level of nesting in code. In order to set it up, see the customization section of this tutorial. For example, the command to set the shift width to 4 characters is :set sw=4.
The following commands indent your lines or remove the indentation, and can be specified with count:
<<
Shifts the current line to the left by one shift width.
>>
Shifts the current line to the right by one shift width.
The VI editor also has a helpful feature which checks your source code for any hanging parentheses or braces. The % command will look for the left parenthesis or brace corresponding to a particular right parenthesis or brace and vice versa. Place the cursor onto a parenthesis or brace and type % to move the cursor to the corresponding parenthesis or brace. This is useful to check for unclosed parentheses or braces. If a parenthesis or brace exists without a matching parenthesis or brace, VI will beep at you to indicate that no matching symbol was found.
Word and Character Searching
The VI editor has two kinds of searches: string and character. For a string search, the / and ? commands are used. When you start these commands, the command just typed will be shown on the bottom line, where you type the particular string to look for. These two commands differ only in the direction where the search takes place. The / command searches forwards (downwards) in the file, while the ? command searches backwards (upwards) in the file. The n and N commands repeat the previous search command in the same or opposite direction, respectively. Some characters have special meanings to VI, so they must be preceded by a backslash (\) to be included as part of the search expression.
Emacs Editor
Emacs is another editor available in UNIX. Like vi, emacs is a screen editor. Unlike vi, emacs is not an insertion mode editor, meaning that any character typed in emacs is automatically inserted into the file, unless it includes a command prefix.
Commands in emacs are either control characters (hold down the
One other distinction between emacs and vi is that emacs allows you to edit several files at once. The window for emacs can be divided into several windows, each of which contains a view into a buffer. Each buffer typically corresponds to a different file. Many of the commands listed below are for reading files into new buffers and moving between buffers.
To use emacs on a file, type
emacs filename
If the file named filename exists, then the first screen's worth of the file is displayed; if it doesn't exist, a help message is displayed.
The easiest way to learn emacs is to start it up and go through the on-line tutorial. To access the on-line tutorial, type
ESC help-with-tutorial
immediately after you have started emacs. The tutorial directs you further in learning the basic commands. One notational point you should know is that the tutorial uses M- to mean ESC.
* C-h help-command: first character in lots of useful help commands
* C-h t help-with-tutorial: command to run the tutorial
C-h i information: describes most of the emacs commands in man style pages
C-h k describe-key: tells you what a particular key stroke does
* C-h a command-apropos: prompts for a string and
then searches for all emacs commands that contains that string
ESC ? also does command-apropos
* C-h ? help-for-help: describes how to use the help facilities
To give you a head start, the following table lists the basic commands you need to know to use emacs to edit a file. An asterisk (* or star) to the left of a command indicate it is one to learn immediately.
________________________________________
Help Commands
File Reading and Writing Commands
* C-x C-f find-file: first prompts for a filename and
then loads that file into a editor buffer of the same name
* C-x C-s save-buffer: saves the buffer into the associated filename
C-x C-w write-named-file: prompts for a new filename and writes the buffer into it
Cursor/Screen Movement Commands
Depending on the terminal, some of the cursor movement can be handled by the arrow keys.
* C-a move cursor to (at) beginning-of-line
C-e move cursor to end-of-line
* C-f move cursor forward one character
* C-b move cursor backward one character
* C-n move cursor to next line
* C-p move cursor to previous line
C-v scroll file forward by one screenful
ESC v scroll file backward by one screenful
* ESC < go to beginning-of-buffer
* ESC > go to end-of-buffer
ESC f move cursor forward one word
ESC b move cursor backward one word
Copy and Delete Commands
C-d delete-char: delete character under cursor
ESC d delete-word: delete from cursor to end of word immediately ahead of the cursor
* C-k kill-line: delete the rest of the current line
* C-@ set-mark-command: mark is used to indicate the beginning of an area of text to be yanked
* C-w kill-region: delete the area of text between the mark and the current cursor position
* C-y yank: insert at current cursor location whatever was most recently deleted
ESC w copy-region-as-kill: copy area between mark and cursor into kill-buffer
so that it can be yanked into someplace else
Search Commands
* C-s isearch-forward: prompts for text string and
then searches from the current cursor position forwards in the buffer
C-r isearch-backward: like isearch-forward,
but searches from the current cursor position to end of buffer for text string
ESC % query-replace: prompts for a search string and
a string with which to replace the search string
Window and Buffer Commands
C-x 0 zero-window: deletes current window
C-x 2 double-window: splits current window into two parts,
allowing you to edit at two different locations in the same file
or permitting you to view two different files at the same time
C-x b switch-to-buffer: display a different buffer on the screen
C-x o other-window: move the cursor to the other window
(assuming that you have two windows/buffers open at once
* C-x C-b list-buffers: lists those buffers currently loaded into emacs
Exiting Emacs, Fixing Mistakes and Other Important Stuff
* C-x C-c save-buffers-kill-emacs: when you are finished editing,
to save the edited but unsaved buffers
and to return you to the UNIX prompt
* C-g keyboard-quit: if while typing a command you make a mistake and want to stop,
this aborts a command in progress
C-u universal-argument: if you want to do a command several times,
type this command
followed by a number (for the number of times)
followed by the command you wish repeated
* C-x u undo: undoes the last command typed, in case you made a mistake
* ESC x execute-extended-command: prompts for the name of an emacs command;
allows you to execute a command
if you know roughly what it is called
but cannot remember the key strokes for it
________________________________________
Joe's Own Editor
JOE is a full featured terminal-based screen editor which is distributed under the GNU General Public License (GPL). JOE has been around since 1988 and comes standard with many Linux distributions.
JOE is being maintained by its original author Joseph Allen, plus all of the people who send bug reports, feature suggestions and patches to the project web site. JOE is hosted by SourceForge.net and its source code is controlled under CVS. Over the last few years there has been about one major new release a year, usually in the April-May timeframe.
JOE is a blending of MicroPro's venerable microcomputer word processor WordStar and Richard Stallman's famous LISP based text editor GNU-EMACS (but it does not use code from either program): most of the basic editing keys are the same as in WordStar as is the overall feel of the editor. JOE also has some of the key bindings and many of the powerful features of EMACS.
JOE is written in C and its only dependency is libc. This makes JOE very easy to build (just "configure" and "make install"), making it feasible to include on small systems and recovery disks. The compiled binary is about 300K in x86. Note that JOE can use either the termcap or terminfo terminal capabilities databases (or a built-in termcap entry for ANSI terminals). The choice is controlled by a "configure" option. If terminfo is used, a library is required to access the database (on some systems this library is ncurses, but JOE does not use curses to control the terminal- it has its own code for this).
Much of the look and feel of JOE is determined by its simple configuration file "joerc". Several variants of the editor are installed by default in addition to "joe": "jmacs" (emulate GNU-EMACS), "jstar" emulate WordStar, "jpico" emulate the Pine mailer editor PICO and "rjoe"- a restricted version of JOE which allows the used to only edit the file given on the command line. JOE is linked to several names. The name which is used to invoke the editor with "rc" tacked on the end gives the name of configuration file to use. It is thus easy for you to make your own variant if you want. Also you can customize the editor by copying the system "joerc" file to your home directory.
Here is a basic screen shot of JOE running in a Cygwin console:
Here is a screen shot showing several windows- the first has some example double-wide characters, the second is the same buffer as the first, but in hex-dump view mode, the third is a shell window and the fourth shows a selected rectangular block of numbers and their sum:
JOE has the following features:
• Multi-file search and replace- file list is either given on command line or by a UNIX command (grep/find) run from within JOE.
• Mouse support, including wheel (works best when using xterm). The mouse can resize windows, scroll windows, select and paste text, and select menu entries.
• Context display on status line: allows you to see name of function cursor is in.
• UTF-8 support, optional auto-detect of UTF-8 files.
• Syntax highlighting for more than 40 languages.
• Hexadecimal edit mode. Use JOE as a disk editor: joe -overwrite -hex /dev/hda1,0,512 (edit first sector of /dev/hda1).
• Non-destructive editing of binary files even when handling MS-DOS or UNIX line endings.
• Swap file allows editing files larger than memory.
• Context sensitive on-line help.
• Bash-like TAB completion and history for all prompts, or jump into the completion menu and use it to traverse the file system.
• Complete word in edit buffer by hitting ESC Enter (uses other words in buffer for dictionary).
• EMACS-compatible file locks and file modification checking.
• Shell windows.
• Multiple-windows onto same or different files.
• Compile and step through errors or Grep and step through finds.
• Goto matching character delimiter ( [ { < which skips comments and quoted matter.
• Goto matching word delimiter, including XML tags and C preprocessor directives.
• Ctrl-arrow key block selection.
• Search and replace system, including regular expression and optional incremental search. Regular expression key for matching balanced C expressions.
• Tags file search (tab completion at tags search prompt uses tags file as database).
• Spell check commands which invoke aspell or ispell. Language for aspell can be passed through editor.
• Paragraph format which preserves news/mail quoting indentation characters.
• Unlimited Undo and Redo.
• Yank buffer allows stepping through and insertion of previously deleted text.
• State file restores history buffers, yank buffer and last file cursor positions.
• Cursor position history allows you to step through previously visited areas of a file.
• Multiple interactive keyboard macros. Macros can be assigned to key sequences in joerc file.
• Block move/copy/delete/filter.
• Rectangle (columnar) block mode- search and replace can be narrowed to the rectangular block. Rectangular blocks can be filtered through UNIX commands.
• Overtype/Insert modes.
• Indent/Unindent (shift block left or right).
• Auto-indent mode.
• Picture mode for ASCII graphics.
• Line number mode displays line number of each line.
• Powerful scientific calculator with block statistics functions (sum/standard-deviation/count highlighted block of numbers).
• Termcap/Terminfo support allows JOE to use any terminal or terminal emulator.
• Can accept data from a pipe, for example: ls | joe
GEDIT
gedit is the official text editor of the GNOME desktop environment.
While aiming at simplicity and ease of use, gedit is a powerful general purpose text editor.
Currently it features:
• Full support for internationalized text (UTF-8)
• Configurable syntax highlighting for various languages (C, C++, Java, HTML, XML, Python, Perl and many others)
• Undo/Redo
• Editing files from remote locations
• File reverting
• Print and print preview support
• Clipboard support (cut/copy/paste)
• Search and replace
• Go to specific line
• Auto indentation
• Text wrapping
• Line numbers
• Right margin
• Current line highlighting
• Bracket matching
• Backup files
• Configurable fonts and colors
• A complete online user manual
gedit features also a flexible plugin system which can be used to dynamically add new advanced features to gedit itself. See the plugins page for more info on the existing plugins.
Go to the screenshots page to see gedit in action!
gedit is released under the GNU General Public License (GPL).
ActiveState Komodo
ActiveState Komodo
Developed by
ActiveState
Stable release
5.1.3 (2009-4-29; 8 days ago) [+/−]
Preview release
none (n/a) [+/−]
Written in
Python, JavaScript, XUL
Operating system
Cross-platform
Available in
English
Type
IDE
License
IDE:Proprietary; Edit: MPL/GPL/LGPL
Website
http://www.activestate.com/komodo/
ActiveState Komodo is the name given to a family of integrated development environment (IDE) applications produced by software firm ActiveState.
•
Komodo IDE
Komodo IDE is an IDE for dynamic programming languages built on the Mozilla platform. It supports dynamic languages, including JavaScript, Perl, PHP, Python, Ruby, and Tcl; framework stacks like Ruby on Rails and CakePHP; and client libraries such as the Yahoo! UI Library and Dojo.
ActiveState added browser-side support in Komodo IDE 4.0, including debugging, DOM viewer, catalog support, HTTP Inspector, and code intelligence for languages such as JavaScript, CSS, HTML, and XML, enabling programmers to edit and debug Ajax code and multi-language files.
Komodo IDE, although not Open Source, is extensible using standard Mozilla APIs based on XUL, XBL, and XPCOM, plus Python and JavaScript.
Komodo IDE is available for Linux, Mac OS X, and Microsoft Windows platforms.
Komodo Edit
Komodo Edit is a free text editor for dynamic programming languages introduced in January 2007. With the release of version 4.3, Komodo Edit is built on top of the Open Komodo project.
Komodo Edit inherits many features of Komodo IDE, like the full range of supported languages (Perl, PHP, Python, Ruby, Tcl) and platforms (Linux, Mac OS X, and Windows ). And like Komodo IDE, Komodo Edit also supports browser-side languages like JavaScript, CSS, HTML, and XML.
It was developed for programmers who need a multi-language editor with broad functionality, but not the features of an IDE, like debugging, DOM viewer, interactive shells, and source code control integration
REFERENCE CITED
www.wikipedia.com
www.linuxforum.com
www.gedit.com
Linux Bible
Encarta encylopedia
Linux prgramming
shell script for linux
History of all great works in to witness that no great work was ever done without either active or passive support of a person ‘surrounding and one’s close quarters . thus is it not hard to conclude how active assistance from senior could positively impact the execution of a project .I am highly thankful to our learned faculty Ms.Harleen mam for his active guidence throughout the completion of project .
Last but not least , I would also want to extend my appreciation to those who could not be mentioned here but have well played their role to inspire me behind the certain.
---Shubham Verma
Create a shell script called prog1 that will accept the input and check if the input is a directory file and is readible, writable .If so then all ordinary files under that directory should be listed out one by one.For each ordinary file that is writable the user should be asked if the file is to be deleted or not .If ‘yes’ file should be deleted else next file is checked .At the end the script should display the following message …
. . . Ordinary file deleted from the directory.
. . . Ordinary files remain in the directory.
Shorter the program greater will be its brilliancy . . .
Same is in my case Scripting is done with very simple and basic commands of Linux programming and that too not having very critical logic
Scripting is done giving below
vi prog1.sh
echo “Enter the Input”
read fd
if [(-d $fd)&(-r $fd)&(-w $fd)]
then
echo “ls fd”
echo “Enter the file name which is to be selected”
let i=1-100
read fn
if [-w $fn]
then
echo “Press enter to delete this file”
mkdir b
cd b
cp $b $fn
cd
rm -i $fn
else
mkdir c
cd c
cp $c $fn
cd
fi
let i=i+1
fi
echo “ls b”
echo “These many files are deleted from the directory”
echo “ls c”
echo “These many remains in the directory”
I. Opening the vi editor.
II. Inputting the File
III. Checking the file is a directory , readible ,writable or not.
IV. If is true , then listing all files in the directory.
V. Asking the user which file is to be selected
VI. After that , taking the loop from 1 to 100 and inputting the selected file ‘fn’ ,checking whether ‘fn’ has writable permission or not.
VII. If yes, then displaying ,”Press Enter to delete this file”.
VIII. In that condition only , creating & changing the directory into ‘b’ and copying the file ‘fn’ into the directory ‘b’. And then removing the file ‘fn’.
IX. But if the condition is being false then copying the ‘fn’ into the another directory ‘c’.
X. And at the last , listing all the deleted files and remaing files from the directory ‘b’ and ‘c’.
“directory ‘b’ stores the the deleted file from the main the directory where as ‘c’ directory stores all the remaing files from the main directory.
-d checks if the file is directory or not. . .
-r checks if the file is readible or not. . .
-w checks if the file is writable or not. . .
echo It is just use to display the context to the console . . .
read It is used for initialsing and inputting the variables . . .
if[] It is just used for cheking out the cndition given in the program . . .
let ____ It is just to neglect the ‘$’ sign in the calculation . . .
mkdir It is just create a new directory . . .
cd It is just used to change the present working directory . . .
rm -i It is just remove the file by confirming it first . . .
cp It is just use to copy a file . . .
ls - It is just use to list the all the files in that directory . . .
-d File exist and it is adirectory . . .
-w File exist and it have readible permission to it . . .
-r File exist and it have writable permission to it . . .
fd It is the inputted directory name . . .
fn It is the file name to which user has selected from the directory fd . . .
b It is the directory to which all deleted files are stored . . .
c It is the directory to which remaining files are stored . . .
n It contains total no of files in the directory fd . . .
i It is the counter variable for the for loop from 1 to n . . .
History of all great works in to witness that no great work was ever done without either active or passive support of a person ‘surrounding and one’s close quarters . thus is it not hard to conclude how active assistance from senior could positively impact the execution of a project .I am highly thankful to our learned faculty Ms.Harleen mam for his active guidence throughout the completion of project .
Last but not least , I would also want to extend my appreciation to those who could not be mentioned here but have well played their role to inspire me behind the certain.
---Shubham Verma
Create a shell script called prog1 that will accept the input and check if the input is a directory file and is readible, writable .If so then all ordinary files under that directory should be listed out one by one.For each ordinary file that is writable the user should be asked if the file is to be deleted or not .If ‘yes’ file should be deleted else next file is checked .At the end the script should display the following message …
. . . Ordinary file deleted from the directory.
. . . Ordinary files remain in the directory.
Shorter the program greater will be its brilliancy . . .
Same is in my case Scripting is done with very simple and basic commands of Linux programming and that too not having very critical logic
Scripting is done giving below
vi prog1.sh
echo “Enter the Input”
read fd
if [(-d $fd)&(-r $fd)&(-w $fd)]
then
echo “ls fd”
echo “Enter the file name which is to be selected”
let i=1-100
read fn
if [-w $fn]
then
echo “Press enter to delete this file”
mkdir b
cd b
cp $b $fn
cd
rm -i $fn
else
mkdir c
cd c
cp $c $fn
cd
fi
let i=i+1
fi
echo “ls b”
echo “These many files are deleted from the directory”
echo “ls c”
echo “These many remains in the directory”
I. Opening the vi editor.
II. Inputting the File
III. Checking the file is a directory , readible ,writable or not.
IV. If is true , then listing all files in the directory.
V. Asking the user which file is to be selected
VI. After that , taking the loop from 1 to 100 and inputting the selected file ‘fn’ ,checking whether ‘fn’ has writable permission or not.
VII. If yes, then displaying ,”Press Enter to delete this file”.
VIII. In that condition only , creating & changing the directory into ‘b’ and copying the file ‘fn’ into the directory ‘b’. And then removing the file ‘fn’.
IX. But if the condition is being false then copying the ‘fn’ into the another directory ‘c’.
X. And at the last , listing all the deleted files and remaing files from the directory ‘b’ and ‘c’.
“directory ‘b’ stores the the deleted file from the main the directory where as ‘c’ directory stores all the remaing files from the main directory.
-d checks if the file is directory or not. . .
-r checks if the file is readible or not. . .
-w checks if the file is writable or not. . .
echo It is just use to display the context to the console . . .
read It is used for initialsing and inputting the variables . . .
if[] It is just used for cheking out the cndition given in the program . . .
let ____ It is just to neglect the ‘$’ sign in the calculation . . .
mkdir It is just create a new directory . . .
cd It is just used to change the present working directory . . .
rm -i It is just remove the file by confirming it first . . .
cp It is just use to copy a file . . .
ls - It is just use to list the all the files in that directory . . .
-d File exist and it is adirectory . . .
-w File exist and it have readible permission to it . . .
-r File exist and it have writable permission to it . . .
fd It is the inputted directory name . . .
fn It is the file name to which user has selected from the directory fd . . .
b It is the directory to which all deleted files are stored . . .
c It is the directory to which remaining files are stored . . .
n It contains total no of files in the directory fd . . .
i It is the counter variable for the for loop from 1 to n . . .
Last but not least , I would also want to extend my appreciation to those who could not be mentioned here but have well played their role to inspire me behind the certain.
---Shubham Verma
Create a shell script called prog1 that will accept the input and check if the input is a directory file and is readible, writable .If so then all ordinary files under that directory should be listed out one by one.For each ordinary file that is writable the user should be asked if the file is to be deleted or not .If ‘yes’ file should be deleted else next file is checked .At the end the script should display the following message …
. . . Ordinary file deleted from the directory.
. . . Ordinary files remain in the directory.
Shorter the program greater will be its brilliancy . . .
Same is in my case Scripting is done with very simple and basic commands of Linux programming and that too not having very critical logic
Scripting is done giving below
vi prog1.sh
echo “Enter the Input”
read fd
if [(-d $fd)&(-r $fd)&(-w $fd)]
then
echo “ls fd”
echo “Enter the file name which is to be selected”
let i=1-100
read fn
if [-w $fn]
then
echo “Press enter to delete this file”
mkdir b
cd b
cp $b $fn
cd
rm -i $fn
else
mkdir c
cd c
cp $c $fn
cd
fi
let i=i+1
fi
echo “ls b”
echo “These many files are deleted from the directory”
echo “ls c”
echo “These many remains in the directory”
I. Opening the vi editor.
II. Inputting the File
III. Checking the file is a directory , readible ,writable or not.
IV. If is true , then listing all files in the directory.
V. Asking the user which file is to be selected
VI. After that , taking the loop from 1 to 100 and inputting the selected file ‘fn’ ,checking whether ‘fn’ has writable permission or not.
VII. If yes, then displaying ,”Press Enter to delete this file”.
VIII. In that condition only , creating & changing the directory into ‘b’ and copying the file ‘fn’ into the directory ‘b’. And then removing the file ‘fn’.
IX. But if the condition is being false then copying the ‘fn’ into the another directory ‘c’.
X. And at the last , listing all the deleted files and remaing files from the directory ‘b’ and ‘c’.
“directory ‘b’ stores the the deleted file from the main the directory where as ‘c’ directory stores all the remaing files from the main directory.
-d checks if the file is directory or not. . .
-r checks if the file is readible or not. . .
-w checks if the file is writable or not. . .
echo It is just use to display the context to the console . . .
read It is used for initialsing and inputting the variables . . .
if[
let ____ It is just to neglect the ‘$’ sign in the calculation . . .
mkdir It is just create a new directory . . .
cd It is just used to change the present working directory . . .
rm -i
cp
ls -
-d File exist and it is adirectory . . .
-w File exist and it have readible permission to it . . .
-r File exist and it have writable permission to it . . .
fd It is the inputted directory name . . .
fn It is the file name to which user has selected from the directory fd . . .
b It is the directory to which all deleted files are stored . . .
c It is the directory to which remaining files are stored . . .
n It contains total no of files in the directory fd . . .
i It is the counter variable for the for loop from 1 to n . . .
History of all great works in to witness that no great work was ever done without either active or passive support of a person ‘surrounding and one’s close quarters . thus is it not hard to conclude how active assistance from senior could positively impact the execution of a project .I am highly thankful to our learned faculty Ms.Harleen mam for his active guidence throughout the completion of project .
Last but not least , I would also want to extend my appreciation to those who could not be mentioned here but have well played their role to inspire me behind the certain.
---Shubham Verma
Create a shell script called prog1 that will accept the input and check if the input is a directory file and is readible, writable .If so then all ordinary files under that directory should be listed out one by one.For each ordinary file that is writable the user should be asked if the file is to be deleted or not .If ‘yes’ file should be deleted else next file is checked .At the end the script should display the following message …
. . . Ordinary file deleted from the directory.
. . . Ordinary files remain in the directory.
Shorter the program greater will be its brilliancy . . .
Same is in my case Scripting is done with very simple and basic commands of Linux programming and that too not having very critical logic
Scripting is done giving below
vi prog1.sh
echo “Enter the Input”
read fd
if [(-d $fd)&(-r $fd)&(-w $fd)]
then
echo “ls fd”
echo “Enter the file name which is to be selected”
let i=1-100
read fn
if [-w $fn]
then
echo “Press enter to delete this file”
mkdir b
cd b
cp $b $fn
cd
rm -i $fn
else
mkdir c
cd c
cp $c $fn
cd
fi
let i=i+1
fi
echo “ls b”
echo “These many files are deleted from the directory”
echo “ls c”
echo “These many remains in the directory”
I. Opening the vi editor.
II. Inputting the File
III. Checking the file is a directory , readible ,writable or not.
IV. If is true , then listing all files in the directory.
V. Asking the user which file is to be selected
VI. After that , taking the loop from 1 to 100 and inputting the selected file ‘fn’ ,checking whether ‘fn’ has writable permission or not.
VII. If yes, then displaying ,”Press Enter to delete this file”.
VIII. In that condition only , creating & changing the directory into ‘b’ and copying the file ‘fn’ into the directory ‘b’. And then removing the file ‘fn’.
IX. But if the condition is being false then copying the ‘fn’ into the another directory ‘c’.
X. And at the last , listing all the deleted files and remaing files from the directory ‘b’ and ‘c’.
“directory ‘b’ stores the the deleted file from the main the directory where as ‘c’ directory stores all the remaing files from the main directory.
-d checks if the file is directory or not. . .
-r checks if the file is readible or not. . .
-w checks if the file is writable or not. . .
echo It is just use to display the context to the console . . .
read It is used for initialsing and inputting the variables . . .
if[
let ____ It is just to neglect the ‘$’ sign in the calculation . . .
mkdir It is just create a new directory . . .
cd It is just used to change the present working directory . . .
rm -i
cp
ls -
-d File exist and it is adirectory . . .
-w File exist and it have readible permission to it . . .
-r File exist and it have writable permission to it . . .
fd It is the inputted directory name . . .
fn It is the file name to which user has selected from the directory fd . . .
b It is the directory to which all deleted files are stored . . .
c It is the directory to which remaining files are stored . . .
n It contains total no of files in the directory fd . . .
i It is the counter variable for the for loop from 1 to n . . .
chandrayan
DHARAMJEET SINGH SYAN
Regn. No. : 10807535
Roll No. : RD4801A04
Course Code : PHY111
Term Paper
On
MISSION CHANDERYAAN
Submitted to : Mr. Harjit Singh Ghotra
ACKNOWLEDGEMENT
I, Dharamjeet Singh Syan , a student of B Tech – Mechanical Engineering(Integrated MBA ), am thankful to my respected teacher Mr. Harjit Singh Ghotra, who has made it possible for me to do this project successfully as he has guided me in how to present the project.
I am also thankful to the excellent environment provided by the university which made it possible for me to do the project sincerely.
“Hard Work Is the Key To Success” – the saying is hence proved truth by presenting this perfect project.
Chandrayaan-1
Chandrayaan-1 lifts off on the PSLV-C11
Organization : Indian Space Research Organisation
Mission type : Orbiter
Satellite of : Moon
Orbital insertion date : 12 November 2008
Launch date : 22 October 2008 from SriharikotaAndhra Pradesh, India
Launch vehicle : PSLV-C11
Mission duration : 2 years
NSSDC ID : 2008-052A
Home page : Chandrayaan-1
Chandrayaan-1
Chandrayaan-1, is India's first mission to the Moon launched by India's national space agency the Indian Space Research Organisation (ISRO). The unmanned lunar exploration mission includes a lunar orbiter and an impactor. India launched the spacecraft by a modified version of the PSLV C11 on 22 October 2008 from Satish Dhawan Space Centre, Sriharikota, Nellore District, Andhra Pradesh about 80 km north of Chennai at 06:22 IST (00:52 UTC). The mission is a major boost to India's space program, as India competes with Asian nations China and Japan in exploring the Moon. The vehicle was successfully inserted into lunar orbit on 8 November 2008.
On November 14, 2008, the Moon Impact Probe separated from the Moon-orbiting Chandrayaan at 20:06 and impacted the lunar south pole in a controlled manner, making India the fourth country to place its flag on the Moon. The MIP impacted near the crater Shackleton, at the lunar south pole, at 20:31 on 14 November 2008 releasing subsurface debris that could be analysed for presence of water ice.
The estimated cost for the project is Rs. 386 crore (US$ 80 million).
The remote sensing lunar satellite had a weight of 1,380 kilograms (3,042 lb) at launch and 675 kilograms (1,488 lb) in lunar orbit and carries high resolution remote sensing equipment for visible, near infrared, and soft and hard X-ray frequencies. Over a two-year period, it is intended to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. The polar regions are of special interest, as they might contain ice. The lunar mission carries five ISRO payloads and six payloads from other international space agencies including NASA, ESA, and theBulgarian Aerospace Agency, which were carried free of cost.
CONTENTS
Objectives
Specifications
Specific areas of study
Payloads
• Indian
• Non-Indian
Space flight
• Earth orbits burns
• Lunar orbit insertion
• Injection of MIP on Lunar surface
• Rise in space craft temperature
• Mapping of minerals
• Mapping of Apollo landing sites
• Detection of X-Ray signals
• Full Earth image
Chanderyaan -2
NASA Lunar Outpost
Reactions and statements
• Reactions within India
• International reactions
The stated scientific objectives of the mission are:
• To design, develop, launch and orbit a spacecraft around the Moon using an Indian-made launch vehicle.
• Conduct scientific experiments using instruments on-board the spacecraft which will yield the following results:
o Preparation of a three-dimensional atlas (with high spatial and altitude resolution of 5-10 m) of both the near and far side of the Moon.
o Chemical and mineralogical mapping of the entire lunar surface at high spatial resolution, mapping particularly the chemical elements Magnesium, Aluminium, Silicon, Calcium, Iron, Titanium, Radon, Uranium, & Thorium.
o The impact of a sub-satellite (Moon Impact Probe — MIP) on the surface on the Moon as a fore-runner to future soft-landing missions.
Specifications
Mass
1380 kg at launch, 675 kg at lunar orbit, and 523 kg after releasing the impactor.
Dimensions
Cuboid in shape of approximately 1.5 m
Communications
X band, 0.7 m diameter parabolic antenna for payload data transmission. The Telemetry, Tracking & Command (TTC) communication operates in S band frequency.
Power
The spacecraft is mainly powered by its solar array, which includes one solar panel covering a total area of 2.15 x 1.8 m generating 700 W of power, which is stored in a 36 A•h lithium-ion battery. The spacecraft uses a bipropellant integrated propulsion system to reach lunar orbit as well as orbit and altitude maintenance while orbiting the Moon.
Specific areas of study
• High-resolution mineralogical and chemical imaging of the permanently shadowed north and south polar regions.
• Search for surface or sub-surface water-ice on the Moon, especially at the lunar poles.
• Identification of chemicals in lunar highland rocks.
• Chemical stratigraphy of lunar crust by remote sensing of the central uplands of large lunar craters, and of the South Pole Aitken Region (SPAR), where interior material may be expected.
• To map the height variation of the lunar surface features.
• Observation of X-ray spectrum greater than 10 keV and stereographic coverage of most of the Moon's surface with 5 m resolution
• To provide new insights in understanding the Moon's origin and evolution.
Payloads
Indian
• TMC or the Terrain Mapping Camera is a CCD camera with 5 m resolution and a 40 km swath in the panchromatic band and will be used to produce a high-resolution map of the Moon. The aim of this instrument is to completely map the topography of the Moon. The camera works in the visible region of the electromagnetic spectrum and captures black and white stereo images. When used in conjunction with data from Lunar Laser Ranging Instrument (LLRI), it can help in better understanding of the lunar gravitational field as well. TMC was built by the ISRO's Space Applications Centre (SAC) at Ahmedabad. The TMC was successfully tested on 29 October 2008 through a set of commands issued from ISTRAC.
• HySI or Hyper Spectral Imager will perform mineralogical mapping in the 400-900 nm band with a spectral resolution of 15 nm and a spatial resolution of 80 m.
• C1XS or X-ray fluorescence spectrometer covering 1- 10 keV, will map the abundance of Mg, Al, Si, Ca, Ti, and Fe at the surface with a ground resolution of 25 km, and will detect solar flux. This payload is collaboration between Rutherford Appleton laboratory, U.K, ESA and ISRO. It was activated on 23 November, 2008.
• MIP or the Moon Impact Probe developed by the ISRO, is an impact probe which consisted of a C-band Radar altimeter for measurement of altitude of the probe, a video imaging system for acquiring images of the lunar surface and a mass spectrometer for measuring the constituents of the lunar atmosphere. It was ejected at 20:00 hours IST on 14 November, 2008. The Moon Impact Probe successfully crash landed at the lunar south pole at 20:31 hours IST on 14 November, 2008. It carried with it a picture of the Indian flag. India is now the fourth nation to place a flag on the Moon after the Soviet Union, United States and Japan.
Non-Indian
• SARA, The Sub-keV Atom Reflecting Analyser from the ESA will map composition using low energy neutral atoms sputtered from the surface.
• M3, the Moon Mineralogy Mapper from Brown University and JPL (funded by NASA) is an imaging spectrometer designed to map the surface mineral composition. It was switched on 17 December, 2008.
• SIR-2, A near infrared spectrometer from ESA, built at the Max Planck Institute for Solar System Research, Polish Academy of Science and University of Bergen, will also map the mineral composition using an infrared grating spectrometer. The instrument will be similar to that of the Smart-1 SIR. It was switched on 19 November, 2008 and scientific observations were successfully started on 20 November, 2008.
Space flight
Chandrayaan-1 was launched on 22 October 2008 at 6.22 am IST from Satish Dhawan Space Centre using ISRO's 44.4 metre tall four-stage PSLV launch rocket, and it took 21 days to reach final lunar orbit. ISRO's telemetry, tracking and command network (ISTRAC) at Peenya in Bangalore, will track and control Chandrayaan-1 over the next two years of its life span. Chandrayaan-1 was sent to the Moon in a series of orbit-increasing manoeuvres around Earth instead of a direct shot to the Moon. At launch the spacecraft was inserted into geostationary transfer orbit(GTO) with an apogee of 22,860 km and a perigee of 255 km. The apogee was increased with a series of five orbit burns conducted over a period of 13 days after launch. 100 days of Chandrayaan-1 launch : Scientists from India, US and Europe conducted high-level review of Chandrayaan-1 on January 29, 2009 after the Chandrayaan-1 completed its 100 days in space.
Earth orbit burns
First orbit burn
The first orbit-raising manoeuvre of Chandrayaan-1 spacecraft was performed at 09:00 hrs IST on 23 October 2008 when the spacecraft’s 440 Newton Liquid Engine was fired for about 18 minutes by commanding the spacecraft from Spacecraft Control Centre (SCC) at ISRO Telemetry, Tracking and Command Network (ISTRAC) at Peenya, Bangalore. With this Chandrayaan-1’s apogee was raised to 37,900 km, and its perigee to 305 km. In this orbit, Chandrayaan-1 spacecraft took about 11 hours to go around the Earth once.
Second orbit burn
The second orbit-raising manoeuvre of Chandrayaan-1 spacecraft was carried out on 25 October 2008 at 05:48 IST when the spacecraft’s engine was fired for about 16 minutes, raising its apogee to 74,715 km, and its perigee to 336 km, thus completing 20 percent of its journey. In this orbit, Chandrayaan-1 spacecraft took about twenty-five and a half hours to go round the Earth once. This is the first time an Indian spacecraft has gone beyond the 36,000 km high geostationary orbit and reached an altitude more than twice that height.
Third orbit burn
The third orbit raising manoeuvre was initiated on 26 October 2008 at 07:08 IST when the spacecraft’s engine was fired for about nine and a half minutes. With this its apogee was raised to 164,600 km, and the perigee to 348 km. In this orbit, Chandrayaan-1 took about 73 hours to go around the Earth once.
Final orbit burn
The fifth and final orbit raising manoeuvre was carried out on 4 November 2008 04:56 am IST when the spacecraft’s engine was fired for about two and a half minutes resulting in Chandrayaan-1 entering theLunar Transfer Trajectory with an apogee of about 380,000 km.
Lunar orbit insertion
Chandrayaan-1 successfully completed the lunar orbit insertion operation on 8th Nov 2008 at 16:51 IST. This manoeuvre involved firing of the liquid engine for 817 seconds (about thirteen and half minutes) when the spacecraft passed within 500 km from the Moon. The satellite was placed in an elliptical orbit that passed over the polar regions of the Moon, with 502 km aposelene (point farthest away from the Moon) and 504 km periselene (nearest to the Moon). The orbital period was estimated to be around 11 hours. With the successful completion of this operation, India became the fifth nation to put a vehicle in lunar orbit.
First orbit reduction
First Lunar Orbit Reduction Manoeuvre of Chandrayaan-1 was carried out successfully on 9 November 2008 at 20:03 IST. During this, the engine of the spacecraft was fired for about 57 seconds. This reduced the periselene from 504 km to 200 km while aposelene remained unchanged at 7,502 km. In this elliptical orbit, Chandrayaan-1 took about ten and a half hours to circle the Moon once.
Second orbit reduction
This manoeuvre, which resulted in steep decrease in Chandrayaan-1’s aposelene from 7,502 km to 255 km and its periselene from 200 km to 187 km, was carried out on 10 November 2008 at 21:58 IST. During this manoeuvre, the engine was fired for about 866 seconds (about fourteen and half minutes). Chandrayaan-1 took two hours and 16 minutes to go around the Moon once in this orbit.
Third orbit reduction
Third Lunar Orbit Reduction was carried out by firing the on board engine for 31 seconds on 11 November 2008 at 18:30 IST. This reduced the periselene from 187 km to 101 km, while the aposelene remained constant at 255 km. In this orbit Chandrayaan-1 took two hours and 9 minutes to go around the Moon once.
Final orbit
Chandrayaan-1 spacecraft was successfully placed into a mission-specific lunar polar orbit of 100 km above the lunar surface on 12 November 2008. In the final orbit reduction manoeuvre, Chandrayaan-1’s aposelene was reduced from 255 km to 100 km while the periselene was reduced from 101 km to 100 km. In this orbit, Chandrayaan-1 takes about two hours to go around the Moon once. Two of the 11 payloads – the Terrain Mapping Camera (TMC) and the Radiation Dose Monitor (RADOM) – have already been successfully switched on. The TMC has successfully taken pictures of both the Earth and the Moon.
Injection of MIP on lunar surface
The Moon Impact Probe took this close-up picture of the Moon's surface during its descent.
The Moon Impact Probe (MIP) crash-landed on the lunar surface on 14 November 2008, 15:01 UTC (20:31 Indian Standard Time (IST)) near the crater Shackleton at the south pole. The MIP was one of eleven scientific instruments (payloads) onboard Chandrayaan-1.
The MIP separated from Chandrayaan at 100 km from lunar surface and began its nosedive at 14:36 UTC (20:06 IST) going into a free fall for thirty minutes. As it fell, it kept sending information back to the mother satellite which, in turn, beamed the information back to Earth. The altimeter then also began recording measurements to prepare for a rover to land on the lunar surface during a second Moon mission planned for 2012. When the MIP was closer to the surface, rockets were fired to slow down its speed and to soften impact.
Rise in space craft temperature
ISRO had reported on 25 November, 2008 that Chandrayaan-1's temperature had risen above normal to 50°C, they said that it had occurred due to higher than normal temperatures in lunar orbit. The temperature has been brought down by about 10°C by rotating the space craft by 20 degrees and switching off some of the instruments. Subsequently ISRO reported on 27 November, 2008 that the space craft was operating under normal temperature conditions. In subsequent reports ISRO says, since the space craft is still recording higher than normal temperatures, it will be running only one instrument at a time until January 2009 when lunar orbital temperature conditions are said to stabilise. The space craft was experiencing these high temperatures because it is currently over the sunlit side of the Moon, where it will be receiving energy both from the Sun and infrared radiation given off by the Moon.
Mapping of minerals
The mineral content on the lunar surface has been mapped with Moon Mineralogy Mapper(M3), an NASA instrument on board the orbiter. The presence of iron has been reiterated and changes in rock and mineral composition has been identified. Orientale Basin region of the Moon has been mapped, indicating abundance of iron-bearing minerals such as pyroxene.
Mapping of Apollo landing sites
The landing sites of the Apollo Moon missions have been mapped by the orbiter using multiple payloads. Six of the sites have been mapped including that of Apollo 11, the first mission that put humans on the Moon.
Full Earth image
On March 25, 2009 Chandrayaan beamed back the first images of the Earth in its entirety. These images were taken with the TMC. Previous imaging has been done on only part of the Earth. The new images show Asia, parts of Africa and Australia with India being in the center.
NASA Lunar Outpost
According to Ben Bussey, senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, Chandrayaan's imagery will be used to decide the future Lunar outpost that NASA has recently announced. Bussey told SPACE.com, "India's Chandrayaan-1 lunar orbiter has a good shot at further identifying possible water ice-laden spots with a US-provided low-power imaging radar." Bussey advised — one of two US experiments on the Indian Moon probe. "The idea is that we find regions of interest with Chandrayaan-1 radar. We would investigate those using all the capabilities of the radar on NASA's Lunar Reconnaissance Orbiter", Bussey added, "a Moon probe to be launched late in 2008." (The LRO is now scheduled for launch 24 April 2009).
Reactions and statements
Reactions within India
• Indian President Pratibha Patil and Vice-President Mohammad Hamid Ansari sent congratulatory messages to the space scientists for the successful launch.
• Prime Minister, Dr. Manmohan Singh sent congratulatory messages to the space scientists for the successful launch, and L. K. Advani, the leader of opposition congratulated the ISRO scientists on launch.
• The Chief Minister of Gujarat Narendra Modi, visited the ISRO centre in Ahmedabad and congratulated the Indian scientists on their achievement.
• The Chief Minister of Karnataka B. S. Yeddyurappa, visited the ISRO Indian Deep Space Network in Byalalu and congratulated Madhavan Nair and his team on their achievement.
International reaction
• NASA Administrator Michael D. Griffin congratulated Indian scientists: "Congratulations to our Indian colleagues on the successful launch of the Chandrayaan-1 spacecraft, which is carrying two NASA instruments. India's first lunar mission will provide important insight."
• US White House hailed India's maiden Moon mission as "encouraging" and "exciting".
• U.S. President elect Barack Obama viewed the launch of Chandrayaan as a challenge to the United States. He stated "We are reminded just how urgently we must revitalise our space program, if we are to remain the undisputed leader in space, science, and technology".
Taken over the equatorial region of the Moon by TMC, the picture shows the uneven surface of the Moon with numerous craters. On the lower left, part of the crater Torricelli is seen.
Taken over the polar region of the Moon by TMC, the picture shows many large and numerous small craters. The bright terrain on the lower left is the rim of 117-km-wide crater Moretus.
Pictures of the Moon's surface taken by Moon Impact Probe (MIP) as it approached the lunar surface after separating from Chandrayaan-1
Regn. No. : 10807535
Roll No. : RD4801A04
Course Code : PHY111
Term Paper
On
MISSION CHANDERYAAN
Submitted to : Mr. Harjit Singh Ghotra
ACKNOWLEDGEMENT
I, Dharamjeet Singh Syan , a student of B Tech – Mechanical Engineering(Integrated MBA ), am thankful to my respected teacher Mr. Harjit Singh Ghotra, who has made it possible for me to do this project successfully as he has guided me in how to present the project.
I am also thankful to the excellent environment provided by the university which made it possible for me to do the project sincerely.
“Hard Work Is the Key To Success” – the saying is hence proved truth by presenting this perfect project.
Chandrayaan-1
Chandrayaan-1 lifts off on the PSLV-C11
Organization : Indian Space Research Organisation
Mission type : Orbiter
Satellite of : Moon
Orbital insertion date : 12 November 2008
Launch date : 22 October 2008 from SriharikotaAndhra Pradesh, India
Launch vehicle : PSLV-C11
Mission duration : 2 years
NSSDC ID : 2008-052A
Home page : Chandrayaan-1
Chandrayaan-1
Chandrayaan-1, is India's first mission to the Moon launched by India's national space agency the Indian Space Research Organisation (ISRO). The unmanned lunar exploration mission includes a lunar orbiter and an impactor. India launched the spacecraft by a modified version of the PSLV C11 on 22 October 2008 from Satish Dhawan Space Centre, Sriharikota, Nellore District, Andhra Pradesh about 80 km north of Chennai at 06:22 IST (00:52 UTC). The mission is a major boost to India's space program, as India competes with Asian nations China and Japan in exploring the Moon. The vehicle was successfully inserted into lunar orbit on 8 November 2008.
On November 14, 2008, the Moon Impact Probe separated from the Moon-orbiting Chandrayaan at 20:06 and impacted the lunar south pole in a controlled manner, making India the fourth country to place its flag on the Moon. The MIP impacted near the crater Shackleton, at the lunar south pole, at 20:31 on 14 November 2008 releasing subsurface debris that could be analysed for presence of water ice.
The estimated cost for the project is Rs. 386 crore (US$ 80 million).
The remote sensing lunar satellite had a weight of 1,380 kilograms (3,042 lb) at launch and 675 kilograms (1,488 lb) in lunar orbit and carries high resolution remote sensing equipment for visible, near infrared, and soft and hard X-ray frequencies. Over a two-year period, it is intended to survey the lunar surface to produce a complete map of its chemical characteristics and 3-dimensional topography. The polar regions are of special interest, as they might contain ice. The lunar mission carries five ISRO payloads and six payloads from other international space agencies including NASA, ESA, and theBulgarian Aerospace Agency, which were carried free of cost.
CONTENTS
Objectives
Specifications
Specific areas of study
Payloads
• Indian
• Non-Indian
Space flight
• Earth orbits burns
• Lunar orbit insertion
• Injection of MIP on Lunar surface
• Rise in space craft temperature
• Mapping of minerals
• Mapping of Apollo landing sites
• Detection of X-Ray signals
• Full Earth image
Chanderyaan -2
NASA Lunar Outpost
Reactions and statements
• Reactions within India
• International reactions
The stated scientific objectives of the mission are:
• To design, develop, launch and orbit a spacecraft around the Moon using an Indian-made launch vehicle.
• Conduct scientific experiments using instruments on-board the spacecraft which will yield the following results:
o Preparation of a three-dimensional atlas (with high spatial and altitude resolution of 5-10 m) of both the near and far side of the Moon.
o Chemical and mineralogical mapping of the entire lunar surface at high spatial resolution, mapping particularly the chemical elements Magnesium, Aluminium, Silicon, Calcium, Iron, Titanium, Radon, Uranium, & Thorium.
o The impact of a sub-satellite (Moon Impact Probe — MIP) on the surface on the Moon as a fore-runner to future soft-landing missions.
Specifications
Mass
1380 kg at launch, 675 kg at lunar orbit, and 523 kg after releasing the impactor.
Dimensions
Cuboid in shape of approximately 1.5 m
Communications
X band, 0.7 m diameter parabolic antenna for payload data transmission. The Telemetry, Tracking & Command (TTC) communication operates in S band frequency.
Power
The spacecraft is mainly powered by its solar array, which includes one solar panel covering a total area of 2.15 x 1.8 m generating 700 W of power, which is stored in a 36 A•h lithium-ion battery. The spacecraft uses a bipropellant integrated propulsion system to reach lunar orbit as well as orbit and altitude maintenance while orbiting the Moon.
Specific areas of study
• High-resolution mineralogical and chemical imaging of the permanently shadowed north and south polar regions.
• Search for surface or sub-surface water-ice on the Moon, especially at the lunar poles.
• Identification of chemicals in lunar highland rocks.
• Chemical stratigraphy of lunar crust by remote sensing of the central uplands of large lunar craters, and of the South Pole Aitken Region (SPAR), where interior material may be expected.
• To map the height variation of the lunar surface features.
• Observation of X-ray spectrum greater than 10 keV and stereographic coverage of most of the Moon's surface with 5 m resolution
• To provide new insights in understanding the Moon's origin and evolution.
Payloads
Indian
• TMC or the Terrain Mapping Camera is a CCD camera with 5 m resolution and a 40 km swath in the panchromatic band and will be used to produce a high-resolution map of the Moon. The aim of this instrument is to completely map the topography of the Moon. The camera works in the visible region of the electromagnetic spectrum and captures black and white stereo images. When used in conjunction with data from Lunar Laser Ranging Instrument (LLRI), it can help in better understanding of the lunar gravitational field as well. TMC was built by the ISRO's Space Applications Centre (SAC) at Ahmedabad. The TMC was successfully tested on 29 October 2008 through a set of commands issued from ISTRAC.
• HySI or Hyper Spectral Imager will perform mineralogical mapping in the 400-900 nm band with a spectral resolution of 15 nm and a spatial resolution of 80 m.
• C1XS or X-ray fluorescence spectrometer covering 1- 10 keV, will map the abundance of Mg, Al, Si, Ca, Ti, and Fe at the surface with a ground resolution of 25 km, and will detect solar flux. This payload is collaboration between Rutherford Appleton laboratory, U.K, ESA and ISRO. It was activated on 23 November, 2008.
• MIP or the Moon Impact Probe developed by the ISRO, is an impact probe which consisted of a C-band Radar altimeter for measurement of altitude of the probe, a video imaging system for acquiring images of the lunar surface and a mass spectrometer for measuring the constituents of the lunar atmosphere. It was ejected at 20:00 hours IST on 14 November, 2008. The Moon Impact Probe successfully crash landed at the lunar south pole at 20:31 hours IST on 14 November, 2008. It carried with it a picture of the Indian flag. India is now the fourth nation to place a flag on the Moon after the Soviet Union, United States and Japan.
Non-Indian
• SARA, The Sub-keV Atom Reflecting Analyser from the ESA will map composition using low energy neutral atoms sputtered from the surface.
• M3, the Moon Mineralogy Mapper from Brown University and JPL (funded by NASA) is an imaging spectrometer designed to map the surface mineral composition. It was switched on 17 December, 2008.
• SIR-2, A near infrared spectrometer from ESA, built at the Max Planck Institute for Solar System Research, Polish Academy of Science and University of Bergen, will also map the mineral composition using an infrared grating spectrometer. The instrument will be similar to that of the Smart-1 SIR. It was switched on 19 November, 2008 and scientific observations were successfully started on 20 November, 2008.
Space flight
Chandrayaan-1 was launched on 22 October 2008 at 6.22 am IST from Satish Dhawan Space Centre using ISRO's 44.4 metre tall four-stage PSLV launch rocket, and it took 21 days to reach final lunar orbit. ISRO's telemetry, tracking and command network (ISTRAC) at Peenya in Bangalore, will track and control Chandrayaan-1 over the next two years of its life span. Chandrayaan-1 was sent to the Moon in a series of orbit-increasing manoeuvres around Earth instead of a direct shot to the Moon. At launch the spacecraft was inserted into geostationary transfer orbit(GTO) with an apogee of 22,860 km and a perigee of 255 km. The apogee was increased with a series of five orbit burns conducted over a period of 13 days after launch. 100 days of Chandrayaan-1 launch : Scientists from India, US and Europe conducted high-level review of Chandrayaan-1 on January 29, 2009 after the Chandrayaan-1 completed its 100 days in space.
Earth orbit burns
First orbit burn
The first orbit-raising manoeuvre of Chandrayaan-1 spacecraft was performed at 09:00 hrs IST on 23 October 2008 when the spacecraft’s 440 Newton Liquid Engine was fired for about 18 minutes by commanding the spacecraft from Spacecraft Control Centre (SCC) at ISRO Telemetry, Tracking and Command Network (ISTRAC) at Peenya, Bangalore. With this Chandrayaan-1’s apogee was raised to 37,900 km, and its perigee to 305 km. In this orbit, Chandrayaan-1 spacecraft took about 11 hours to go around the Earth once.
Second orbit burn
The second orbit-raising manoeuvre of Chandrayaan-1 spacecraft was carried out on 25 October 2008 at 05:48 IST when the spacecraft’s engine was fired for about 16 minutes, raising its apogee to 74,715 km, and its perigee to 336 km, thus completing 20 percent of its journey. In this orbit, Chandrayaan-1 spacecraft took about twenty-five and a half hours to go round the Earth once. This is the first time an Indian spacecraft has gone beyond the 36,000 km high geostationary orbit and reached an altitude more than twice that height.
Third orbit burn
The third orbit raising manoeuvre was initiated on 26 October 2008 at 07:08 IST when the spacecraft’s engine was fired for about nine and a half minutes. With this its apogee was raised to 164,600 km, and the perigee to 348 km. In this orbit, Chandrayaan-1 took about 73 hours to go around the Earth once.
Final orbit burn
The fifth and final orbit raising manoeuvre was carried out on 4 November 2008 04:56 am IST when the spacecraft’s engine was fired for about two and a half minutes resulting in Chandrayaan-1 entering theLunar Transfer Trajectory with an apogee of about 380,000 km.
Lunar orbit insertion
Chandrayaan-1 successfully completed the lunar orbit insertion operation on 8th Nov 2008 at 16:51 IST. This manoeuvre involved firing of the liquid engine for 817 seconds (about thirteen and half minutes) when the spacecraft passed within 500 km from the Moon. The satellite was placed in an elliptical orbit that passed over the polar regions of the Moon, with 502 km aposelene (point farthest away from the Moon) and 504 km periselene (nearest to the Moon). The orbital period was estimated to be around 11 hours. With the successful completion of this operation, India became the fifth nation to put a vehicle in lunar orbit.
First orbit reduction
First Lunar Orbit Reduction Manoeuvre of Chandrayaan-1 was carried out successfully on 9 November 2008 at 20:03 IST. During this, the engine of the spacecraft was fired for about 57 seconds. This reduced the periselene from 504 km to 200 km while aposelene remained unchanged at 7,502 km. In this elliptical orbit, Chandrayaan-1 took about ten and a half hours to circle the Moon once.
Second orbit reduction
This manoeuvre, which resulted in steep decrease in Chandrayaan-1’s aposelene from 7,502 km to 255 km and its periselene from 200 km to 187 km, was carried out on 10 November 2008 at 21:58 IST. During this manoeuvre, the engine was fired for about 866 seconds (about fourteen and half minutes). Chandrayaan-1 took two hours and 16 minutes to go around the Moon once in this orbit.
Third orbit reduction
Third Lunar Orbit Reduction was carried out by firing the on board engine for 31 seconds on 11 November 2008 at 18:30 IST. This reduced the periselene from 187 km to 101 km, while the aposelene remained constant at 255 km. In this orbit Chandrayaan-1 took two hours and 9 minutes to go around the Moon once.
Final orbit
Chandrayaan-1 spacecraft was successfully placed into a mission-specific lunar polar orbit of 100 km above the lunar surface on 12 November 2008. In the final orbit reduction manoeuvre, Chandrayaan-1’s aposelene was reduced from 255 km to 100 km while the periselene was reduced from 101 km to 100 km. In this orbit, Chandrayaan-1 takes about two hours to go around the Moon once. Two of the 11 payloads – the Terrain Mapping Camera (TMC) and the Radiation Dose Monitor (RADOM) – have already been successfully switched on. The TMC has successfully taken pictures of both the Earth and the Moon.
Injection of MIP on lunar surface
The Moon Impact Probe took this close-up picture of the Moon's surface during its descent.
The Moon Impact Probe (MIP) crash-landed on the lunar surface on 14 November 2008, 15:01 UTC (20:31 Indian Standard Time (IST)) near the crater Shackleton at the south pole. The MIP was one of eleven scientific instruments (payloads) onboard Chandrayaan-1.
The MIP separated from Chandrayaan at 100 km from lunar surface and began its nosedive at 14:36 UTC (20:06 IST) going into a free fall for thirty minutes. As it fell, it kept sending information back to the mother satellite which, in turn, beamed the information back to Earth. The altimeter then also began recording measurements to prepare for a rover to land on the lunar surface during a second Moon mission planned for 2012. When the MIP was closer to the surface, rockets were fired to slow down its speed and to soften impact.
Rise in space craft temperature
ISRO had reported on 25 November, 2008 that Chandrayaan-1's temperature had risen above normal to 50°C, they said that it had occurred due to higher than normal temperatures in lunar orbit. The temperature has been brought down by about 10°C by rotating the space craft by 20 degrees and switching off some of the instruments. Subsequently ISRO reported on 27 November, 2008 that the space craft was operating under normal temperature conditions. In subsequent reports ISRO says, since the space craft is still recording higher than normal temperatures, it will be running only one instrument at a time until January 2009 when lunar orbital temperature conditions are said to stabilise. The space craft was experiencing these high temperatures because it is currently over the sunlit side of the Moon, where it will be receiving energy both from the Sun and infrared radiation given off by the Moon.
Mapping of minerals
The mineral content on the lunar surface has been mapped with Moon Mineralogy Mapper(M3), an NASA instrument on board the orbiter. The presence of iron has been reiterated and changes in rock and mineral composition has been identified. Orientale Basin region of the Moon has been mapped, indicating abundance of iron-bearing minerals such as pyroxene.
Mapping of Apollo landing sites
The landing sites of the Apollo Moon missions have been mapped by the orbiter using multiple payloads. Six of the sites have been mapped including that of Apollo 11, the first mission that put humans on the Moon.
Full Earth image
On March 25, 2009 Chandrayaan beamed back the first images of the Earth in its entirety. These images were taken with the TMC. Previous imaging has been done on only part of the Earth. The new images show Asia, parts of Africa and Australia with India being in the center.
NASA Lunar Outpost
According to Ben Bussey, senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, Chandrayaan's imagery will be used to decide the future Lunar outpost that NASA has recently announced. Bussey told SPACE.com, "India's Chandrayaan-1 lunar orbiter has a good shot at further identifying possible water ice-laden spots with a US-provided low-power imaging radar." Bussey advised — one of two US experiments on the Indian Moon probe. "The idea is that we find regions of interest with Chandrayaan-1 radar. We would investigate those using all the capabilities of the radar on NASA's Lunar Reconnaissance Orbiter", Bussey added, "a Moon probe to be launched late in 2008." (The LRO is now scheduled for launch 24 April 2009).
Reactions and statements
Reactions within India
• Indian President Pratibha Patil and Vice-President Mohammad Hamid Ansari sent congratulatory messages to the space scientists for the successful launch.
• Prime Minister, Dr. Manmohan Singh sent congratulatory messages to the space scientists for the successful launch, and L. K. Advani, the leader of opposition congratulated the ISRO scientists on launch.
• The Chief Minister of Gujarat Narendra Modi, visited the ISRO centre in Ahmedabad and congratulated the Indian scientists on their achievement.
• The Chief Minister of Karnataka B. S. Yeddyurappa, visited the ISRO Indian Deep Space Network in Byalalu and congratulated Madhavan Nair and his team on their achievement.
International reaction
• NASA Administrator Michael D. Griffin congratulated Indian scientists: "Congratulations to our Indian colleagues on the successful launch of the Chandrayaan-1 spacecraft, which is carrying two NASA instruments. India's first lunar mission will provide important insight."
• US White House hailed India's maiden Moon mission as "encouraging" and "exciting".
• U.S. President elect Barack Obama viewed the launch of Chandrayaan as a challenge to the United States. He stated "We are reminded just how urgently we must revitalise our space program, if we are to remain the undisputed leader in space, science, and technology".
Taken over the equatorial region of the Moon by TMC, the picture shows the uneven surface of the Moon with numerous craters. On the lower left, part of the crater Torricelli is seen.
Taken over the polar region of the Moon by TMC, the picture shows many large and numerous small craters. The bright terrain on the lower left is the rim of 117-km-wide crater Moretus.
Pictures of the Moon's surface taken by Moon Impact Probe (MIP) as it approached the lunar surface after separating from Chandrayaan-1
shell script
TERM PAPER
LINUX PROGRAMMING
CSE 207
Topic: Write a shell script to display following menu
1. Display List of currently logged in Users
2. Get Help about any Command
3. List the files and sub-directories under some path
4. Reverse a string
5. Quit
Submitted to: Submitted by:
Ms. Shaveta Sharma Mr. Aditya Kandari
Roll.No. - RB1803B57
Section - B1803
Reg.No -10803872
ACKNOWLEDGEMENT
I, express my gratitude towards our subject teacher for the guidelines and help provided by her in making this project a success. She helped me a lot in completing this project.
I would like to say thank you to all those who are involved in this project including my friends. Their valuable inputs in various matter related to the topic helped me a lot.
I have taken the help of some books and websites, listed in references. I would like to thank the library of the university that acted as a database of knowledge for me.
The various sites visited by me on the internet also helped me a lot in making my term paper a success. I thank again one and all.
CONTENTS
What Is A Linux Shell?
So What Is A Shell Script
Why To Write A Shell Script
The Shell Script
References Cited
WHAT IS LINUX SHELL ?
Computer understand the language of 0's and 1's called binary language.
In early days of computing, instruction are provided using binary language, which is difficult for all of us, to read and write. So in Os there is special program called Shell. Shell accepts your instruction or commands in English (mostly) and if its a valid command, it is pass to kernel.
Shell is a user program or it's environment provided for user interaction. Shell is an command language interpreter that executes commands read from the standard input device (keyboard) or from a file.
Shell is not part of system kernel, but uses the system kernel to execute programs, create files etc.
Several shell available with Linux including:
Shell Name Developed by Where Remark
BASH ( Bourne-Again SHell ) Brian Fox and Chet Ramey Free Software Foundation Most common shell in Linux. It's Freeware shell.
CSH (C SHell) Bill Joy University of California (For BSD) The C shell's syntax and usage are very similar to
the C programming language.
KSH (Korn SHell) David Korn AT & T Bell Labs --
TCSH See the man page.
Type $ man tcsh -- TCSH is an enhanced but completely compatible version of the Berkeley UNIX C shell (CSH).
So What Is Shell Script?
Normally shells are interactive. It means shell accept command from you (via keyboard) and execute them. But if you use command one by one (sequence of 'n' number of commands) , the you can store this sequence of command to text file and tell the shell to execute this text file instead of entering the commands. This is know as shell script.
Shell script defined as:
"Shell Script is series of command written in plain text file. Shell script is just like batch file is MS-DOS but have more power than the MS-DOS batch file."
Why to Write Shell Script ?
• Shell script can take input from user, file and output them on screen.
• Useful to create our own commands.
• Save lots of time.
• To automate some task of day today life.
• System Administration part can be also automated.
THE SHELL SCRIPT
#!/bin/sh
echo “Main Menu”
echo “1. Display List of currently logged in Users”
echo “2. Get Help about any Command”
echo “3. List the files and sub-directories under some path”
echo “4. Reverse a string”
echo “5. Quit “
read opt
if [
case “$opt” in
1) logged( ); ;
2) help( ); ;
3) list( ); ;
4) rev( ); ;
5) echo “You Have Successfully Quitted From Shell Script”
*) echo “Error - Please Enter A Valid Choice”
exit 0
logged( ) {
#function to print users who are logged in
users=`who | cut -d' ' -f1 | sort -u`
for i in $users
do
echo $i
ps -u $i
done
}
help( ) {
#function to get help on any command
echo –n “Enter the command:-”
read com
echo $man –k $com
}
list( ) {
#function to get list of files and sub-directories
echo –n “Enter path”
read path
echo $ls –al $path
}
rev( ) {
#function to reverse a inputed string and show it.
echo -n "enter the string u want to reverse:-"
read string
len =`echo -n $string |wc -c`
echo "no of character is:- $len"
while test $len -gt 0
do
rev =$rev`echo $string |cut -c $len`
len =`expr $len - 1`
done
echo "the reverse string is:-$rev "
}
REFERENCES CITED
Begining Linux Programming 4th Edition – Wrox
Introduction To Linux – Machtelt Garrels
www.free-os.com
www.intuitive.com/wicked/showscript
LINUX PROGRAMMING
CSE 207
Topic: Write a shell script to display following menu
1. Display List of currently logged in Users
2. Get Help about any Command
3. List the files and sub-directories under some path
4. Reverse a string
5. Quit
Submitted to: Submitted by:
Ms. Shaveta Sharma Mr. Aditya Kandari
Roll.No. - RB1803B57
Section - B1803
Reg.No -10803872
ACKNOWLEDGEMENT
I, express my gratitude towards our subject teacher for the guidelines and help provided by her in making this project a success. She helped me a lot in completing this project.
I would like to say thank you to all those who are involved in this project including my friends. Their valuable inputs in various matter related to the topic helped me a lot.
I have taken the help of some books and websites, listed in references. I would like to thank the library of the university that acted as a database of knowledge for me.
The various sites visited by me on the internet also helped me a lot in making my term paper a success. I thank again one and all.
CONTENTS
What Is A Linux Shell?
So What Is A Shell Script
Why To Write A Shell Script
The Shell Script
References Cited
WHAT IS LINUX SHELL ?
Computer understand the language of 0's and 1's called binary language.
In early days of computing, instruction are provided using binary language, which is difficult for all of us, to read and write. So in Os there is special program called Shell. Shell accepts your instruction or commands in English (mostly) and if its a valid command, it is pass to kernel.
Shell is a user program or it's environment provided for user interaction. Shell is an command language interpreter that executes commands read from the standard input device (keyboard) or from a file.
Shell is not part of system kernel, but uses the system kernel to execute programs, create files etc.
Several shell available with Linux including:
Shell Name Developed by Where Remark
BASH ( Bourne-Again SHell ) Brian Fox and Chet Ramey Free Software Foundation Most common shell in Linux. It's Freeware shell.
CSH (C SHell) Bill Joy University of California (For BSD) The C shell's syntax and usage are very similar to
the C programming language.
KSH (Korn SHell) David Korn AT & T Bell Labs --
TCSH See the man page.
Type $ man tcsh -- TCSH is an enhanced but completely compatible version of the Berkeley UNIX C shell (CSH).
So What Is Shell Script?
Normally shells are interactive. It means shell accept command from you (via keyboard) and execute them. But if you use command one by one (sequence of 'n' number of commands) , the you can store this sequence of command to text file and tell the shell to execute this text file instead of entering the commands. This is know as shell script.
Shell script defined as:
"Shell Script is series of command written in plain text file. Shell script is just like batch file is MS-DOS but have more power than the MS-DOS batch file."
Why to Write Shell Script ?
• Shell script can take input from user, file and output them on screen.
• Useful to create our own commands.
• Save lots of time.
• To automate some task of day today life.
• System Administration part can be also automated.
THE SHELL SCRIPT
#!/bin/sh
echo “Main Menu”
echo “1. Display List of currently logged in Users”
echo “2. Get Help about any Command”
echo “3. List the files and sub-directories under some path”
echo “4. Reverse a string”
echo “5. Quit “
read opt
if [
case “$opt” in
1) logged( ); ;
2) help( ); ;
3) list( ); ;
4) rev( ); ;
5) echo “You Have Successfully Quitted From Shell Script”
*) echo “Error - Please Enter A Valid Choice”
exit 0
logged( ) {
#function to print users who are logged in
users=`who | cut -d' ' -f1 | sort -u`
for i in $users
do
echo $i
ps -u $i
done
}
help( ) {
#function to get help on any command
echo –n “Enter the command:-”
read com
echo $man –k $com
}
list( ) {
#function to get list of files and sub-directories
echo –n “Enter path”
read path
echo $ls –al $path
}
rev( ) {
#function to reverse a inputed string and show it.
echo -n "enter the string u want to reverse:-"
read string
len =`echo -n $string |wc -c`
echo "no of character is:- $len"
while test $len -gt 0
do
rev =$rev`echo $string |cut -c $len`
len =`expr $len - 1`
done
echo "the reverse string is:-$rev "
}
REFERENCES CITED
Begining Linux Programming 4th Edition – Wrox
Introduction To Linux – Machtelt Garrels
www.free-os.com
www.intuitive.com/wicked/showscript
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