What is Solid: Definition and 1000 Discussions

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.

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  1. chwala

    Find the volume of the solid bound by the three coordinate planes

    Also, $$V=\dfrac{1}{4} \int_4^0 \left[\int_{2-0.5y}^2 (4-2x-y) dx\right] dy$$ $$V=\dfrac{1}{4} \int_4^0\left [4x-x^2-xy]^2_{2-0.5y} \right] dy$$ $$V=\dfrac{1}{4} \int_4^0 \left [(4-2y)-(4(2-0.5y)-(2-0.5y)^2-(2-0.5y)y] \right] dy$$ $$V=\dfrac{1}{4} \int_4^0 \left [(4-2y)-(2-0.5y)^2 \right]...
  2. Sr1

    How Does Band Gap Influence Lattice Spacing in Materials?

    How can we link the band gap to lattice spacing? For (a), if we purely do dimension analysis, then I would guess $$a=\frac{\hbar c}{E_g}$$. But what's the reason behind this answer, and will the true lattice spacing be larger or smaller? For (b), I guess $$\lambda=\frac{\hbar c}{E_g}$$ due to...
  3. S

    I When Water acts like Glue (flat surfaces)

    Water like glue This topic could have more meaning on a chemistry forum. Firts of telling my doupt, i will inform you why i put this question. My goal is controlling an obejct more accurately. I notice that sometimes a solid with plain face on a wet surface is difficult to remove. Besides it...
  4. J

    B Is it possible to ionise a solid, so that it has no electrons left?

    Hi, is it possible to ionise a solid, so that it has no electrons left? Josiah
  5. Slimy0233

    Requesting Resources and Animations to understand Solid State Physics

    TL;DR Summary: I need animations to understand physics better. Any links and animations would be very appreciated. I have started learning Solid state physics and I am struggling somewhat to understand and imagine certain things. I feel like this is one area of physics which needs extensive...
  6. S

    I So what are the definitions of gas, liquid, solid?

    Obviously, we know intuitively what they mean, but it seems that physicists have developed an objective definition for all of these. If I were to guess, I'd say that: - a gas is vastly less compressible than a liquid or solid (i.e., which are considered in thermodynamics as basically...
  7. M

    I Understanding Diffraction Condition in Kittle's Intro to Solid State Physics

    I am going over the diffraction condition section in Kittle's Introduction to Solid State Physics physics and I am having a hard time understanding why the phase difference angle for the incident wave is positive while the phase angle difference for the diffracted wave is negative. Thank you...
  8. chwala

    Find the surface area of the given solid

    My question is on how did they determine the limits of integration i.e ##2## and ##3## as highlighted? Thanks
  9. besebenomo

    Einstein solid state model exercise

    I tried to solve it considering the canonical ensemble (since the system is at the equilibrium with temperature T) and started finding the partition function:The problem is I am not sure if I have done it correctly and need help because I don't really know where to check.
  10. Philip Koeck

    I Is elastic scattering of electrons by a solid possible?

    In electron microscopy of thin solid specimens elastic scattering is treated as the main process responsible for formation of (phase contrast) images and diffraction patterns. However, if an electron changes direction it should lose energy by producing a breaking radiation photon. How can it be...
  11. G

    Equilibrium of a rigid solid on a rod

    Figure: Attempt at a Solution: $$F=k\Delta x=lk\sin \theta$$ $$\delta x=0 \quad \textrm{when} \theta=0$$ $$\sum M_C=0\rightarrow$$ $$\rightarrow Pl\cos \theta -F_yl\cos \theta -F_xl\sin \theta =0\rightarrow$$ $$\rightarrow Pl\cos \theta -Fl\cos^2 \theta -Fl\sin^2 \theta=0\rightarrow$$...
  12. abdulbadii

    Is anhydrous sodium hypochlorite stable in solid form?

    Can there be NaClO sold in solid form? If yes how common is it and its comparison in practical use to the most common liquid form?
  13. Philip Koeck

    Does radon remain inside solid radium?

    When radium atoms inside solid radium turn into radon do they stay in their lattice positions at room temperature or do they diffuse/tunnel to the surface?
  14. negarina

    Can a single-phase solid solution have a martensitic transformation?

    I'm trying to investigate the possibility of martensitic transformation in a non-iron alloy, described as a single-phase alpha-solid-solution (Nickel-Silver CuNi12Zn25Pb1, CW404J). I know that Cu-Ni-Zn alloys with higher zinc amounts show even shape memory effects. And that CuNi12Zn25Pb1 is no...
  15. J

    B Gas planets with solid satellites

    I assume that planets and their satellites are created more or less at the same time. Why gaseous planets like Saturn have solid rings and satellites?
  16. T

    What is a recommended textbook for solid mechanics?

    Summary: In need of a textbook on solid mechanics Hello, I was asked to teach a class in FE analysis (this is not the issue) for solid mechanics (and, specifically, plane stress and strain) The issue is that some students will be deficient in solid mechanics (long story, I will have the time...
  17. LCSphysicist

    Density of a solid and Clapeyron equation

    So i think i am missing something pretty dumb, but anyway: $$|\Delta P_{ressure}| = \rho_{s} g \Delta H$$ Claperyon equation: $$\frac{\Delta P}{\Delta T} = \frac{\Delta L_{m}}{\Delta V_{m} T}$$ Equally both: $$|\rho_{s}| = \frac{|\Delta T \Delta L_{m}|}{|\Delta H \Delta V_{m} g T|}$$ My...
  18. nomadreid

    I A gravity conundrum involving a solid cylinder

    Given a cylinder of height 2k with constant density and total mass M, and another object (for simplicity, a point mass) with mass m on the top of the cylinder; the force of gravitation is calculated between the centers of mass, which for the cylinder is at a distance k from the point mass...
  19. WMDhamnekar

    Finding the volume of the solid

    My attempt : ## \displaystyle\int_0^2 \displaystyle\int_0^{2-x} (2-2x -2y) dy dx = -\frac43 ## But it is wrong.
  20. F

    I A question about potential in the periodic lattice of a solid

    In 3D period lattice, can we separate variable and write potential as V=V(x)+V(y)+V(z)?Then we can reduce the 3D problems into 1D problems. I ask this question because in Solid State Physics books they often consider the 1D problems.
  21. S

    How to describe and discuss different solid matter states?

    The possible forms of solids can be more than just amorphous solids and crystalline solids. I tried a look at a couple of wikipedia articles and one of them showed descriptions of Plasticity, elastic, and Viscoelasticity, but those are not enough. I can only think to give some real world...
  22. mncyapntsi

    E-field of solid sphere with non-uniform charge density

    Hi! I've been trying to attempt this problem over here but the solutions state that the solution is this below? However, from integrating the density and then plugging it into Gauss's law, I get the exact same thing, except a 15 instead of a 5. Could any please help point out if there is an...
  23. samy4408

    I don't understand this problem -- Surface area of a section of a solid sphere

    Sorry i don't understand English very well , if someone want to explain to me this problem?
  24. A

    Difference between a closed solid and a Cartesian surface

    Greetings All! I have hard time to make the difference between the equation of a closed solid and a cartesian surface. For example in the exercice n of the exam I thought that the equation was describing a closed solid " a paraboloid locked by an inclined plane (so I thought I could use...
  25. C

    Solid State Solid State Physics by Springer

    I have the opportunity to get a Springer book for free, provided that it is cheaper than 200$. I am considering an introductory one about Solid State Physics, but I have never heard about a valid one from Springer (I know about Kittel, Ashcroft and Simon only). Do you have any suggestion? Thank...
  26. S

    Volume of solid having triangle base and semicircle slice

    First, I tried to find the equation of line passing through (2, 0) and (0, 3) and I got ##y=3-\frac{3}{2}x## Then I set up equation for the area of one slice, ##A(x)## $$A(x)=\frac{1}{2} \pi r^2$$ $$=\frac{1}{2} \pi \left( \frac{1}{2}y\right)^2$$ $$=\frac{1}{2} \pi...
  27. A

    Understanding Free Fall: Newton's Laws and Gravity

    I don't even know where to begin. I assume that the masses are equal.
  28. Viona

    Best Solid State Physics Book for Beginners

    TL;DR Summary: Gerald Burns's book: Solid State Physics: is it good for begginers or there are best books? Hello, I am looking for the best book to study solid state physics for begginers. Some one recommended Gerald Burns's book: Solid State Physics. So, what is your opinions about this book...
  29. BenDover

    Oxygen gas produced by a Solid element + sodium hydroxide solution?

    Hello. I am wondering; which solid at room temperature elements produce oxygen gas when put into a solution of sodium hydroxide? Thanks
  30. Z

    A Can a Solid Vibrate at Debye Max Frequency?

    Can a solid vibrate with only one frequency-Debye maximal frequency?
  31. PeroK

    I Volume of Solid of Revolution (About the line y = x)

    I found this problem, which I thought was interesting and somewhat original: Calculate the volume of the solid of revolution of the area between the line ##y = x## and the parabola ##y = x^2## from ##x = 0## to ##x = 1## when rotated about the axis ##y = x##.
  32. R

    How Does Vacuum Affect Solid Carryover in a Reactor Vent and Scrubber System?

    I have a system, in which Reactor vent is connected to scrubber. Due to which reactor is under slight vacuum, ~400 mmWC Solid is being charged to the reactor at a very low rate manually. Is there any way to calculate approximate amount of solid which will get carryover to scrubber due to...
  33. Dario56

    Owens - Wendt Model for Surface Energy of Solid - Liquid Interface

    Owens - Wendt model is used for calculating surface energy on liquid - solid interface and it is given by following equation: $$ \gamma_{sl} = \gamma_s + \gamma_l -2(\sqrt {\gamma_l^d \gamma_s^d} + \sqrt {\gamma_l^p \gamma_s^p}) $$ So, if we use liquid and solid of known surface energy as well...
  34. H

    Calculate time of solid passing through a liquid with the given values

    Summary:: We conducted the Marble Race experiment but the data of the time was lost. So I'm wondering if there's a workaround to at least put a rough estimate on it. How long it would take for the marble that weights 6g with a density of 3.4 to cover a distance of 5.8cm passing through a...
  35. P

    3 Phase Harmonics and Solid State Relay Issues

    I have a 3 phase problem that I think might be applicable to this forum. The setup is equipment which contains 5 resistive heaters (A through E). The unit is powered by 208V 3 phase and each of the heaters are hooked up line to line in an unbalanced configuration as follows: L1-L2: Heater D...
  36. sarahjohn

    Finding Specific Heat of a solid

    I thought it might me a ratio of the atomic masses. 27 / 63.6 = x / 900 x = 382 J/kg-K
  37. W

    Volume of solid region double integral

    I sketched this out. With the z=0 and y=0 boundaries, we are looking at ##z \geq 0## and ##y \geq 0## I believe ##0 \leq x \leq 5## because of the boundary of ##y=\sqrt{25-x^2}##. This is my region ##\int_0^5 \int_0^\sqrt{25-x^2} x \, dydx ## ## =\int_0^5 xy \vert_{0}^{\sqrt{25-x^2}} \, dx##...
  38. F

    I Gap between introductory physics & solid state physics?

    The left pic is the initial state and the right pics are 2 different descriptions for a metal under electric field E. Are the 2 on the right contradictory and which is correct?
  39. B

    Solid angle in an optics problem (artificial irradiance of the Earth)

    The actual problem can be found as #2 on this link: https://ocw.mit.edu/courses/mechanical-engineering/2-71-optics-spring-2009/assignments/MIT2_71S09_ups1.pdf I rewrote the problem above with the solar irradiance data that they give. My interpretation is of a square 1 m x 1 m plane sitting...
  40. cemtu

    What makes up a "current" in solid state physics?

    If there is some incoming light that has hit electrons of a N-type doped silicon and broke loose these electrons from their covalent bounds and excited them to the conduction band and also excited the electrons in the donor energy level to the conduction band as well, here we know that, the...
  41. MD LAT 1492

    P & S Waves to Strains-liquid solid interface

    Welcoming any relevant literature!
  42. agnimusayoti

    Calculating the Solid Angle of a Nebula from Earth

    If I assume the nebula is a circle, than the length of arc viewed from Earth is a half of the circumference. So, here $$l = \frac{1}{2} \pi D$$ From the problem, ##D = 125 000 ly##. Because the distance of nebula is much larger than the diameter; I try to approximate R with the distance of...
  43. greg_rack

    Volume of a solid of rotation, obtained rotating a function around x=2

    At first, I inverted the function(##f^{-1}(x)=g(x)##) and calculated the volume through the integral: $$V=\pi\int_{0}^{4}[4-(2-g(x))^2]\ dx$$ but then I questioned myself if the same result could have been obtained without inverting the function. To find such a strategy, I proceeded as follows...
  44. greg_rack

    Volume of a solid of revolution around the y-axis (def. integration)

    First, I calculated the inverse of ##y=e^x## since we're talking about y-axis rotations, which is of course ##x=lny##. Then, helping myself out with a drawing, I concluded that the total volume of the solid must've been: $$V=\pi\int_{0}^{1}1^2 \ dy \ +(\pi\int_{1}^{e}1^2 \ dy \ - \pi...
  45. DrPhysics

    Ibach Luth - Solid State 1.11 (QM model for Van der Waals' equation )

    Hi Everyone, can you guys please help me with the exercise attached? I knot that according to the book, van der Waals interaction is “charge fluctuations in atoms due to zero point motion.” This is correct once you understand that they are not talking about zero point motion of nuclear...
  46. Kaushik

    Find the frictional force acting on a solid cylinder

    This was the answer key provided: My questions are the following: if the force required for rotational equilibrium is more than the limiting static friction, then the body will rotate aka slip over the surface. When it slips, the frictional force will be kinetic and not static, right? If I...
  47. H

    Comparing the kinetic energies among a solid sphere, a cylinder and a hoop

    I did the question as attached, so I think A and D are correct but the given answer is E. Where am I wrong? Thanks.
  48. R

    I Explaining the Continuous Diffraction Spectrum of a Heated Solid

    This is the figure from the book. First of all, from what I know about diffraction, there is an interference pattern but not dispersion of the different colors. If what is happening here can be explained that would be great. Second, the book says the line spectra for different gasses are due to...
  49. Rzbs

    Solid State A book about the history of solid state physics

    What is the best books about the history of solid state physics? I only found this: Out of the Crystal Maze: Chapters from the History of Solid State Physics by Lillian Hoddeson Are there any other books? Thanks for your suggestions
  50. E

    B Volume of a solid at absolute zero

    How much does a typical solid shrink when cooled from room temperature to absolute zero. I can't solve this myself because the coefficient of linear thermal expansion varies with temperature