What is Shell: Definition and 783 Discussions

CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system's DOS BIOS (typically residing in IBMBIO.COM or IO.SYS) during boot. CONFIG.SYS was introduced with DOS 2.0.

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  1. A

    Learn Step-by-Step Linux Shell Scripting for Engineering Applications

    Hai' I am new to the Linux os & i am eager to learn shell scripts for my engineering applications. How to learn step by step any suggestions? I am not aware any programming languages. For my immediatiae application is We have installed custom build software in one particular folder...
  2. N

    Shell balance in spherical coordinates

    I want to derive equation of continuity in spherical coordiantes based on shell balance,can anybody tell me where the hell this sin(theta) comes from? i don't want to transform from cartesian,
  3. S

    Learn How to Write a Generic Unix Shell Script in 4 Easy Steps with ltxprc.sh

    I have never written a shell script, but I am trying to learn. I want to make a generic Unix shell script that will allow me to run four commands in a row... something like this... latex $filename bibtex $filename latex $filename latex $filename I would like to call the script...
  4. S

    Electric Fields in Solid Sphere and Thick Shell

    Homework Statement What is the electric field at r1, r2, r3 for a solid sphere within a thick spherical shell where r1=1.5cm, r2=5.0cm, r3=8.0cm? The solid sphere has a total charge of 3C and the thick shell has a charge of -9C. a=2.0cm, b=4.0cm, c=6.0cm. (a=radius of solid sphere, b=inner...
  5. F

    Building a simple Shell for linux

    Hi, I'm trying to build a shell for Linux, programming it in c currently. I need to be able to read a command like 'copy2flash' so that it'll copy itself to another flash memory, but right now I need the case instruction to be able to recognize the command and print something like "copying to...
  6. S

    Electric Potential conducting shell

    Homework Statement A thin, spherical, conducting shell of radius R is mounted on an isolating support and charged to a potential of -V. An electron is then fired from point P at a distance r from the center of the shell. (r>>R) with an initial speed v_0 and directly towards the shell's...
  7. I

    Cylindrical Shell Method

    How to solve this problem and how to graph it? Please help... y=x^2, y^2=x, about x=-1
  8. V

    Computing Potential of a Spherical Shell w/o using Newton's theorems

    Homework Statement I'm well aware of how to compute the gravitational [electric] potential \Phi due to a spherical mass [charge] distribution of radius R by using Newton's theorems for spherical shells. However, how does one find an analytic expression for \Phi without invoking these theorems...
  9. K

    Electric Field of a Spherical Shell: Sketching E vs. r

    1) A shperical sheel has inner radius R_in and outer radius R_out. The shell contains total charge Q, uniformly distributed. The interior of the shell is empty of matter and charge. Find the electric field for (a)r>R_out, (b)r<R_in, and (c)R_in<r<R_out respectively. Then sketch a graph of E...
  10. tony873004

    Volume by Cylindrical Shells using Method of Shells

    I think I've got it set up correctly, but I'm stuck on the integration. Use the method of cylindrical shells to find the volume generated by rotating the region bounded by y=e^(-x^2), x=0, x=1, rotated about the y axis. \begin{array}{l} \int\limits_{\rm{0}}^{\rm{1}} {\pi r^2 h\,\,dx}...
  11. S

    Electric Field of a Charged Spherical shell

    Homework Statement A solid conducting sphere of radius 2.00 cm has a charge 6.70 µC. A conducting spherical shell of inner radius 4.00 cm and outer radius 5.00 cm is concentric with the solid sphere and has a charge -3.50 µC. Find the electric field at the folowing radii from the center of...
  12. P

    E-field of non-conducting, nonuniform shell

    Homework Statement Right have a shell that has a volym charge distribution P=(G/r^2) and with inner radius a and outer radius b. Now what is the e-field at r<a, a<r<b, r>b Homework Equations gauss's law: surfaceint[E.da]=Qenclosed/epsilon0 Qenc=volymint[PdV) The...
  13. A

    Electromagnetism II - Potential and Electrical Field of a Spherical Shell

    Homework Statement Consider a thin spherical shell having surface charge density σ, and radius a as shown in the diagram (see attachment). Find, by integration over the sphere, the potential at a point P, a distance r fromthe centre of the sphere, for r > a. Using this result also find...
  14. G

    Fock operator for closed shell system

    Hey, The Fock operator for a closed system is given by f = H(core) + sum (2*f - k) where f is the Coulomb operator and k is the exchange operator. The summation goes from 1 to N/2. My questions is why is the summation to N/2 and why does one have to multiply the Coulomb operator by 2...
  15. D

    Distances of electrons in the shell

    Hi people, I'm wandering what the distances of the levels of the electron shell are relative to the centre of the atom. I was told there's a pattern and am investigating it. Regards, Dan
  16. V

    Magnetic Field and infinite cylindrical shell

    Homework Statement An infinite cylindrical shell has inner radius 'a' and outer radius 'b'. The shell carries a charge density J(s) = Cs^2 + Ds. Where 'C' and 'D' are constants. Find B everywhere. Homework Equations The Attempt at a Solution My thought was to find the field do...
  17. A

    [thermodynamics] spherical shell problem

    Homework Statement spherical shell with inner and outer radii a and b, and with temperatures of the inner and outer surfaces T_2 and T_1, the thermal conductivity of the shell is k, derive an equation for the total heat current through the shell Homework Equations...
  18. T

    Need help, can someone explain cylindrical shell method for volume?

    im stuck and my book doesn't explain much on how to get the volume of a shape by the cylindrical shell method. What i really need is to show how to get the general formula of a volume of a sphere and a cone using cylindrical shells.
  19. P

    How to Implement Redirection and Piping in a C Shell Script on UNIX?

    Hello Dudes, I m writing a C shell code in UNIX that takes a user command and executes it, my shell must support the redirection and piping too. Well i succeeded in writing the first one (takes a user command and executes it ) but i m stucked in the other parts :( Can anyone help ...
  20. S

    Potnetial of a spherical Shell

    Griffith's EM problem 3.28 A spherical shell of radius R has a surface charge \sigma = k \cos \theta a) Calculate the dipole moment of this charge distribution. i know that p = r' \sigma(r') da' but here sigma depends on theta would the dipole moment p then turn into p = \theta'...
  21. A

    How Does the Electron Shell Value Relate to Electron Position Within Subshells?

    In my chemistry textbook it says that the electron shell, represented by a value n>= 1, refers to the distance of the electron from the nucleus. It also says that the subshell (represented by L) refers to the shape of the electron cloud. The p subshell is shaped like a peanut or figure eight. My...
  22. F

    Conducting Shell: Exploring Negative & Positive Charges

    I never really understood this... Lets say we have a positive point charge Q at the center of a spherical conducting shell of an inner radius Ri and an outer radius R0. Now my books says that an amount of negative charge equal to -Q must be induced on the inner shell surface (R=Ri), and...
  23. H

    News Shell in Nigeria: Views & Reality

    Guys...i want to have your views on this...like what's the reality,,i mean whatever i read on internet had a very bad image on me regarding shell... i want to listen you...what do you think?? and some links for who are unaware of this... http://www.essentialaction.org/shell/issues.html...
  24. S

    Gauss Law and a hollow spherical shell

    A hollow spherical shell carries a charge density \rho = \frac{k}{r^2} in the region a<= r <= b. As in the figure Find the elctric field in these three regions i) r <a ii) a<r<b iii) r>b SOlution: for r<a it simple.. no exclosed charge for any gaussian sphere within that region...
  25. mbrmbrg

    Volume of Solid Revolving Around X Axis: Cylindrical Shell Method

    Use the method of cylindrical shells to find the volume of the solid generated by revolving aabout the indicated axis the region bounded by the given curves. x=y, x+2y=3, y=0; about the x axis. Latest version of my work: (I don't know how to paste a graph into the post. But I graphed my...
  26. Y

    Electric Field and potential of spherical shell

    A charge punctiform of Q= 12*10\exp-6 C is in the center of a spherical shell conductor charged negatively Q1= 6*10\exp-6 C, and of internal radius = 22 cm ad external=26 cm. Calculate the electric field and potential.
  27. S

    Volume of Rotated Region Using Cylindrical Shells - Step-by-Step Guide

    Please help! How do I do this problem? Using the method of cylindrical shells, find the volume generated by rotating the region the region bounded by the given curves about the specified axis. y=(x-1)^(1/2), y=0, x=5; about y = 3 Please tell me how to set up the integral! Any help is...
  28. S

    How Can I Solve a Volume Problem Using the Cylindrical Shell Method?

    Please help! How do I do this problem? Using the method of cylindrical shells, find the volume generated by rotating the region the region bounded by the given curves about the specified axis. y=(x-1)^(1/2), y=0, x=5; about y = 3 Please tell me how to set up the integral! Any help is...
  29. S

    Calculate Cylindrical Shell Volume: y=x^2, y=0, x=1, x=2

    find volume: y=x^2, y=0, x=1, x=2 about x=1 I found the height to be x^2 and circumference to be 2pi(1-x) So V= \int_1^2 2\pi(1-x)(x^2)dx This is not giving me the right answer.
  30. A

    Gauss' law-thin spherical shell

    Gauss' law---thin spherical shell INTRODUCTION- hello, actually i had been doing some problems on gauss' law from H.C.Verma "concepts of physics". I'm continuously having problem with "wht's the field on the surface of a thin spherical, conducting shell? THE EXACT PROBLEM IS- "Consider the...
  31. Ivan Seeking

    News I think energy independence is going too far - Shell Oil

    "I think energy independence is going too far" - Shell Oil http://www.msnbc.msn.com/id/13296235/page/5/ I think it is clear that this is not who we need making the calls for what's good for the US. Energy needs to be taken out of the hands of big oil...
  32. DaveC426913

    Are Fireworks and Shell Casings Safe for Children to Handle?

    As a parent, how would you feel about finding these items in your house? http://www.davesbrain.ca/miscpix/shells.jpg These are about the size of .22 cartridges. It says 'cartridges for low velocity tools'. That's like an airgun, right? I would be very unhappy to find fireworks hidden...
  33. M

    Integral and cylindrical shell

    Use the method of cylindrical shells to find the volume generated by rotating the region bounded by the given curves about the y-axis. y = x^2 y = 4 x = 0 0 <= x <= 2 So I drew these: http://img131.imageshack.us/img131/9225/math28qi.th.jpg...
  34. J

    E&M a spinning spherical shell

    In fact, This is a question I caucalated in HW. But I still dun understand the answer. Any have the idea about this question? The problem is in this link http://web.mit.edu/8.07/www/probsets/PS6s.pdf The problem No.2
  35. A

    How Does Newton's Shell Theorem Affect Gravitational Force on Earth?

    hello all, I was looking for the equation for the shell therom. general expression for the magnitude of the gravitational force but the one were the one sphear is inside the other, such as a person on the earth.
  36. W

    Nuclear Shell Model: Explaining Nucleon Occupancy

    I don't know how nucleons occupy each energy level, especially the one with multiple states. For example, 1p3/2, there are 4 states in this level, that can be occupied 4 nucleons. If there are 2 nucleons in this level, do they must be paired-up? Why? And if there are 3 nucleons in this...
  37. L

    Little question on the potential in a conducting spherical shell

    The question is: A conducting spherical shell of inner radius b and outer radius c is concentric with a small metal sphere of radius a < b. The metal sphere has a positive charge Q. The total charge on the conducting spherical shell is –Q. What is the potential of the metal sphere? I...
  38. Reshma

    Find the Induced EMF in a Rotating Spherical Shell in a Magnetic Field

    1] A square loop of wire, with sides of length 'a' lies in the first quadrant of the xy-plane, with one corner at the origin. In this region there is a non-uniform time-dependent magnetic field \vec B (y,t) = ky^3t^2\hat z. Find the induced emf in the loop.I applied the flux rule here...
  39. R

    Calculating the Angle of Projection for a Fired Cannon Shell

    A 1250 kg cannon, which fires a 55 kg shell with a speed of 566 m/s relative to the muzzle, is set at an elevation angle of 39° above the horizontal. The cannon is mounted on frictionless rails, so that it recoils freely. What is the speed of the shell with respect to the Earth...
  40. L

    Calculating E in a hemispherical shell using Coulomb's law

    My teacher worked out the following problem as shown below: http://img116.imageshack.us/img116/7656/naamloos27mf.gif The only thing is I don't really understand what he's doing, so could anybody please explain to me a bit more which steps he takes? I would be very greatful! (or maybe...
  41. M

    Intersection of spherical shell and a plane

    I need to know the area of the intersection between a sperical shell and a plane in spherical coordinates. By "shell" I mean a sphere with some differential thickness dR. Basically, I know that the intersection of a sphere and a plane is a circle. But I want to consider this sphere having...
  42. G

    What is the Work Required to Charge a Spherical Shell?

    the problem is: "Calculate the work that must be done to charge a spherical shell of radius R and total charge Q", and I have no idea where to start. You probably have to write some sort of an integral but I don't know how. Can anyone give me a hint?
  43. G

    Work done enclosing sphere with spherical shell - for tommorow

    Hi guys! I have been working on this question all day and am getting no where :cry: I really can't get to grips with Electromagnetism, arghh! The question is :http://www.zen96175.zen.co.uk/problem.GIF I would NOT like anyone to post a solution as its assessed work but I would IMMENSELY...
  44. D

    Moment of inertia of spherical shell

    Hi i have to give a presentation on an example of the defining equation for the moment of inertia of a thin spherical shell. I have to follow the example in my book "elements of Newtonian mechanics". I get most of it but there are a couple steps that the book skips that i cannot. I was...
  45. P

    Electric Potential of a Spherical Shell of Charge

    Ok if you have a spherical shell of radius R with an even distribution of charge then outside the shell at a distance r where r>R I get that the shell can be treated as a point charge and inside the sphere (r<R) the electric potential will be constant. All my notes cover when the shell has no...
  46. K

    Infinite long dielectic cylintrical shell of some finite thickness

    Imagine a infinitly long cylintrical dielectic shell of thickness n. show that the electric field everywhere inside such shell is zero. What is the electirc field within the thickness of the shell?
  47. Z

    X-Ray lines from inner shell ionisation

    Hi Group I have a question about x-ray spectra. If we look at a spectrum from a typical x-ray tube with a wolfram-74 anode, we get a spectrum http://ie.lbl.gov/xray/w.htm with two lines resulting from K-shell ionisation. Question : Why is it (mostly) the electrons from the K-shell that are...
  48. H

    Insulating spherical shell prob

    A small, insulating, spherical shell with inner radius a and outer radius b is concentric with a larger insulating spherical shell with inner radius c and outer radius d. The inner shell has total charge +q distributed uniformly over its volume, and the outer shell has charge -q distributed...
  49. C

    [chem]Lewis Structure-Expanded Valence Shell

    I am currently learning how to draw lewis structures and find it to be really confusing sometimes. For example, for the molecule S03, the correct structure on the textbook is three resonance structures, each with one of the O's forming a double bond with the central atom S. However, why...
  50. S

    Why is an atom with a full shell more stable?

    Hello, I am trying to understand why atoms have a tendency to completely fill their valence shell. What force attracts the electrons in the first place and keeps them from flying off. There is very little explianation for this that I know of besides the 'happy' atom. Thanks, Scott
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