In object-oriented computer programming, SOLID is a mnemonic acronym for five design principles intended to make software designs more understandable, flexible, and maintainable. The principles are a subset of many principles promoted by American software engineer and instructor Robert C. Martin, first introduced in his 2000 paper Design Principles and Design Patterns.The SOLID concepts are
The Single-responsibility principle: "There should never be more than one reason for a class to change." In other words, every class should have only one responsibility.
The Open–closed principle: "Software entities ... should be open for extension, but closed for modification."
The Liskov substitution principle: "Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it". See also design by contract.
The Interface segregation principle: "Many client-specific interfaces are better than one general-purpose interface."
The Dependency inversion principle: "Depend upon abstractions, [not] concretions."The SOLID acronym was introduced later, around 2004, by Michael Feathers.Although the SOLID principles apply to any object-oriented design, they can also form a core philosophy for methodologies such as agile development or adaptive software development.
So, I can't really find this limit:
\lim_{T \to \infty} \ 3Nk {(\epsilon/kT)}^2 \frac{e^{(\epsilon/kT)}}{{(e^{(\epsilon/kT)}-1)}^2}
This is actually the formula for the specific heat of an Einstein solid, which is pretty easy to derive but I haven't been able to calculate the limit to show it...
Homework Statement
A girder made of steel. The length of the girder is 3.77 m. In the middle of the girder there is a fracture. The temperature rises 32° C.
Homework Equations
Find the height that the girder rises from the middle, if it is fixed at both ends. The linear expansion...
i was discussing with ma friend about the possibilities of inducing more vibration to the molecules in a solid matter...
but we could not find a process to do that even though its not practical wanted to know some thing that is theoretical...
hope some one is going to give new ideas..
Homework Statement
In a particular Low Energy Electron Diffraction (LEED) study of a solid surface, electrons at 45 eV were diffracted at \phi = 53 degrees. Calculate the crystal spacing d.
Homework Equations
n\lambda=2dsin(\phi)
\lambda = hc/E
wavelength = c/v
E = vh(n + 1/2)
Note here v...
Homework Statement
The base of a solid is the region between the parabolas x = y2 and x = 3 - 2y2. Find the volume of the solid given that the cross sections perpendicular to the x-axis are:
a) rectangles of height h
b) equilateral triangles
c) isosceles right triangles, hypotenuse on the...
Homework Statement
Question Reads: A circular disk x ^2 + y^2 <= a ^ 2 , a > 0 is revolved about the line x = a.
Find the volume of the resulting solid.
Homework Equations
v = integral(a, b) (2pi)y [F(y) - G(y)] dy
The Attempt at a Solution
Im currently confused, should i...
Homework Statement
Find the surface area generated by rotating y=5-4x^(3/2), 0\leq x\leq 1 about x=2.Homework Equations
SA = 2\pi\int_{a}^{b}(r\cdot ds)dx
The Attempt at a Solution
I simply filled in the formula for the given question, and I'm getting stuck at integration time.
SA =...
This should be a simple question, but I haven't found a clear explanation anywhere yet.
Suppose that there are a bunch of particles in a gas, with their velocities "uniformly distributed over solid angles", and I want to find out what fraction of particles are traveling with velocities in a...
Homework Statement
A long, solid, non-conducting cylinder of radius 8 cm has a non-uniform volume density, ρ, that is a function of the radial distance r from the axis of the cylinder. ρ = A*r2 where A is a constant of value 2.9 μC/m5.
What is the magnitude of the electric field 7 cm...
Homework Statement
A light elastic string has natural length 1 m. One end of the string is attached to the fixed point O and particle P of mass 4 kg is suspended from the other end of the string. When hanging in equilibrium, P is 6/5 m below O. Find the modulus of elasticity of the string...
We know when a body is given a impulsive force in total vaccum, it rotates along with translation about the centre of mass. Now the question is why does it rotate only about the CM and not any other axis. We al know this seems obvious due to insinct but how can the theory explain it. Does any...
Hi,
I have been looking at hoop stresses and the information I have found hasn't been all that useful to me as I am having a hard time converting the thermal contraction of a system into a pressure for the equation (stress=a+b/r^2). This is the thick walled hoop equation
The disc is a few...
Homework Statement
The solid formed when the region bounded by y = x^2 and y = 2 - x^2 is revolved about the x-axis
Homework Equations
disc method with respect to x-axis
the integral of : (pi * (f(x)^2 - g(x)^2))
The Attempt at a Solution
When I square each function and...
Hello!
I need some help regarding a simple matter...
How do I derive an equation for the increase in volume when a liquid goes to a solid state when I know the density of the liquid?
This is a silly doubt i guess...
Homework Statement
When you know an atom's radius you can easily determine its volume by considering it's a sphere.
But when you're dealing with solids, that is, a set of atoms... and then you have bands insted of orbitals... this differente...
Hi everyone, I am have been looking here for a long time, but today is my first day registered. I will be active from now on =). As my first post, I would like to know about the basics and advice about the solid state tesla coil. I would like to do it for my final year project. Is it advisable...
I can sort of understand why water is denser than ice, but for CO2 I cannot understand why it is the other way around. Here is my best shot at understanding it: I imagine H2O's solid structure as a hexagon due to the hydrogen bonds, where each point represents one atom. When these bonds are...
Hello
I have come across this inexplicable fact mentioned in somewhere that for a chain of S = 1 spins, the adjacent bonds can all be in a singlet state i.e. singlets can be shared in this case (forming valence bond solids) but not, for example, for |S| = 1/2, the latter point being clear. I...
Homework Statement
A solid cylinder of radius 20cm is released from a 2.5 high incline. If it rolls down without losing any energy to friction, find the cylinder's velocity at the bottom of the incline and the angular speed at the bottom of the incline.
Homework Equations
The...
If the difference isn't that much, then could a computer theoretically have A HUGE amount of RAM, simply by setting aside a significant portion of the SSD as virtual memory? Maybe a SSD external HD could also be used as virtual memory (for those of us who don't have internal SSD drives yet)
Homework Statement
Hi
Say I have the tight-binding dispersion given by E = -2ta cos(ka). When plotting this, then is it correct that the Fermi level is at the energies satisfying E = 2ta, i.e. a straight line in a (k,E) plot?
I do not know anything about quantum physics, but due to some timetable clashes i hv to take intro solid state and intro quantum phy in the same semester.
One advisor said its ok and he said intro solid state phy is only abt memorizing crystal, but another advisor said it would be tough...
A uniform solid cylinder is set spinning about its axis and is then gently placed, with the axis horizontal, on a rough horizontal table. What fraction of its initial kinetic energy is dissipated in sliding friction before the cylinder eventually rolls smoothly along the plane?
The only...
Homework Statement
hi
i can't seem to make head or tail of this question. here it goes;
find the volume of the solid generated by rotating the area enclosed by the curve y= 2-x^2 and the line y = 1, about y=1.
i am not sure how to start. can someone please explain?
thanks...
Hello there.
Suppose I have a function:
y=3x^{2/3}-1
I want to find the surface area of the solid formed when the part of the curve between x=0 and x=8 is revolved about the x-axis.The curve crosses the x-axis at a point (1/3)^{3/2}
The derivative of the function is...
Homework Statement
Well, first of all, I'm not english spoken, so sorry for the mistakes.
I was trying to calculate the integral below:
\int \int \int_{V} (xy+z) dxdydz
where V is a region in R^{3} bounded by
the sphere x^2+y^2+z^2<=9
the cone z^2<=x^2+y^2
and the plane...
I have gone trough all the material for a solid state physics course I had earlier this exam, and there are three question I actually can't solve, even with all the lecture notes. Here they are:
1. An electron of mass m moves in a square lattice, spacing a. The nearly free approximation...
As solid state physics studies the structure of materials, it is often important to study and to understand molecular theory. This means that you should, for instance, know very well the properties of the states of electrons in atoms with more than one proton in the nucleous. You should also...
Homework Statement
You are polishing a 10.0 g gold ring. (treat as an ideal solid). After doing this for a minute, you find that the ring is hot, having increased the temperature by 15 deg C. Calculate the heat that flows into or out of the system and specify which direction.
Homework...
Homework Statement
Show that the pressure of a solid is given by
P = -\frac{\partial\Phi_0}{\partial V} + \gamma \frac{U}{V}
\Phi_0(V) is the potential energy of the solid when all atoms are at rest in their equilibrium positions and V is the volume of the solid.
U is the internal energy...
Homework Statement
The volume of the solid below the plane: z=2x and above the paraboloid z=x^2 + y^2.
I need help setting this one up, I can handle the evaluating.
The Attempt at a Solution
I just don't know.
hi,
i don't know how to determine bravais lattice from primitive translation vectors.The problem is as:
A crystal with one atom basis, has a set of primitive translational vectors as a1=3i, a2= 3j and a3= (3/2)(i+j+k). What is the bravais lattice.
Homework Statement
A solid sphere is released from rest at the top of an incline of height H and angle 30°. The sphere then rolls down the incline without slipping until it reaches the bottom of the incline, at which point the speed of the center-of-mass of the sphere is found to be 65 cm/s...
How to define a solid cyclinder or any solid objects parametrically?
I can't figure out what do I do with the z axis for example a Cylinder :
x = 0.5*cos(theta)
y = sin(theta)
0*pi <= theta <= 2*pi
This will make an eclipse.
But wad about z?
I know we have to stretch z to the...
Homework Statement
Bounded by the paraboloid z = 4 + 2x2 + 2y2 and the plane z = 10 in the first octant.
Homework Equations
The Attempt at a Solution
Plugging in 10 for z I got 3=x2+y2. From this, I set 0\leqr\leq3\sqrt{}.
I wasn't sure what to do with the first octant, but I...
Homework Statement
The base of a certain solid is an equilateral triangle of side a, with one vertex at the origin and an altitude along the x-axis. Each plane perpendicular to the x-axis intersects the solid in a square cross section with one side in the base of the solid. Find the volume...
Vick's theorem help us to find average value of product of even number of operators. For example look the case of four Bose operators
\langle \hat{b}_1\hat{b}_2\hat{b}_3\hat{b}_4 \rangle =\langle \hat{b}_1\hat{b}_2 \rangle \langle\hat{b}_3\hat{b}_4 \rangle +\langle \hat{b}_1\hat{b}_3 \rangle...
If there was a metal bar:
- with no flexibility
- one end is at earth, on a pivot
- the other end is at the nearest star and free to move
If you moved the bar up and down at the star end, would you see the bar pivot here on Earth immediately or would it take the same time as the speed of...
A solid sphere with radius r is placed on top of a thin disk with radius R. The contact point is the center of the disk. Both objects are uniform and have the same mass M. Calculate the gravitational potential energy of the system. Take the potential energy to be zero when the sphere and the...
Homework Statement
Three forces of F1, F2, and F3 are applied to a solid disk with a mass of 3.6 kg and radius of 2.9 meters. F1 is directly above the center of the disk with a magnitude of 47 Newtons directed in the positive x direction, F2 is directly to the right of the center and has a...
Hi, I have a very basic question on formation of valance and conduction band. It is said that conduction band is above the valance band.
So In a hypothetical lithium molecule formation(for example purpose) : If 100 Lithium atoms combine together, then 1S shell is split into 100 1S shells (one...
Homework Statement
Hi there, I have this iterated integral \displaystyle\int_{0}^{2}\displaystyle\int_{0}^{2-y}\displaystyle\int_{0}^{4-y^2}dxdzdy, and the thing is, does it define a solid? because I think that as it is given it doesn't, but I'm not sure. I think that the cylindric paraboloid...
Hey, I've done a search here on this forum as well as the internet and can't find very many detailed Solid State physics books reccomendations.
I am on a 3rd year class in solid state. The lectures are almost exclusively mathematics, as well as the notes. Id love for a book to follow the...
This concept of when things have higher kinetic energy, their molecules and atoms move more never got to me. I don't get how something having more kinetic energy will make the atoms spread apart and liquify, if enough radiation gets to an object (infrared) in order to reach its melting point, I...
Hi all! Good evening
Here is the Question:
This question is given as a challenge extra credit task, and is a part of a course called solid mechanics 2 that deals more with shear strain and strain matrices.
While trying to translate the question I used the term "strength" instead of...
Homework Statement
Find the volume of the solid generated by revolving the area bounded by
y = sec[x], y= \sqrt{2}
- \pi/4 \leq x \leq \pi/4 about the x-axis
Or
[PLAIN]http://img838.imageshack.us/img838/1552/mathprobq6.jpg Homework Equations
a = lower limit = --\pi/4
b = upper limit = \pi/4
V...
I'm aware of many, many solutions to this on the web (and on the forum) that I can follow, but I'm trying a different way (there are many, after all) and I can't figure out why it's not working, and I'd love to know where my logic is flawed.
I have a solid sphere, and I'm splitting it up into...
Homework Statement
I have just started solid state physics course and we got an assignment to choose one element that we are going to work with. Which element is interesting from a solid state physics point of view (and relatively not too difficult to work with)?
Homework Equations...