Materials Definition and 989 Threads

Consider a cantilever beam of rectangular cross section made up of two materials steel and aluminium. an axial force is applied at one end. the question asked was which material should make up the upper part and which should make up the lower part of the beam? Could someone please help me in...

I was reading about the development of new nanocrystal materials which could allow heat to be manipulated in the same way we now do with light: http://web.mit.edu/newsoffice/2013/how-to-treat-heat-like-light-0111.html What shall we call this approach? Thermoptics? I'm not sure from...

Hi everybody! I am working in a solid state physics group and need to find some heat transfer data to finish my calculations. I need to find the Nusselt number Nu=\frac{hL}{K} describing the heat transfer interface between a Si wafer and helium gas at a variety of temperatures. To find this I...

Hello, why if a ray pass though different materials its direction changes ? couldn't its propagation speed just increase or decrease without having to change the angle ? Thank you

So I've been curious about electrochromic materials lately. In particular, the amount of time it takes for it to switch from transparent to translucent and back. Is the switching time a function of how much material you are applying the voltage across or something? Also, is there any specific...

Is there any material which could change from liquid state to solid state after appiled some force? :smile:

Can anyone recommend any REUs or other summer research programs in materials science and/or physics? I'm interested in your overall impression of the program, but pros/cons could also be helpful.

Recently I've came by this article: "Intercontinental quantum liaisons between entangled electrons in ion traps of thermoluminescent crystals" by Robert Desbrandes and Daniel Van Gent http://arxiv.org/abs/quant-ph/0611109 Researchers used ion traps caused by imperfections of the crystals to...

I am having a bit of trouble finding data about the various combustion temperatures (pyrolysis, smouldering, and flaming) temperatures of everyday materials. Here is the data I have collected so far (forgive me if anything is wrong): *Wood/Paper (C6H10O5)x: Pyrolysis Temperature is 233°C...

In my physics class, we learned that light moves slower when traveling in different materials like water or air. However, it is the fastest in a vacuum. I was wondering why this happens. I read something about a refraction index in the different materials. For example, water has a refraction...

There are materials which block laser beams (or light globally) or weaken its intensity via shading i.e. a beam must have crossed a specific energy barrier in order to pass this shading where beams with less energy will fade and won't pass. The question is, is there a material or a type of...

Hello everybody, We need your advice with a project for building a simple one-beam bridge. We have figured out the dimensions, required load, max allowable stress and safety factor. We need to choose a material that would support our requirements. Which formula should we use to compare...

Why when you compress materials like concrete do they fail in shear? Can the thing you're compressing be too small to fail in this way?

I am an undergraduate student in nuclear engineering, and I want to pursue a PhD in nuclear materials. I have research background in materials corrosion, but my undergraduate university doesn't have courses on materials science for nuclear engineering students. I have noticed that many...

I am taking the Math Subject GRE on Saturday and finding study materials has been nothing short of a major pain. Maybe we should compile all of the study materials we have found into one central location here. I'll start: http://www.math.ucla.edu/~cmarshak/GREWorkshop.html Feel free to...

Hi I am having toruble differentiating between the two. below the curie temperature BaTiO3 behaves as a ferroelectric, the Ti ions are offset from the centre, causing a polar domain. But it has a net polarisation is zero. Now above the curie temperature all the dipole cancel each other out...

Does anyone here know any good Bayesian statistics, Bayesian hypothesis testing, Bayesian inference, etc. learning materials (preferably online)?

Homework Statement A) Which of these materials will feel a force from a permanent magnet - wood, aluminum or steel? B) Will the materials that are attracted by the magnet be attracted to the north pole of the magnet, the south pole, or both? Homework Equations The Attempt at a...

Hi, everyone! I am undergraduate student from China. I am applying to pursue a PhD degree in United States next year. I am interested in nuclear materials, but the problem is that my home school offers little course on materials science. I am affraid that students of materials science may be...

Hello. I know very few things about solid state physics, so my question is very basic.. I'm just searching for a clue.. Have some of you ever heard about, or imagine a way, of decreasing the permeability of a ferromagnetic material? Not by raising temperature, but with electric field or...

Homework Statement QUESTION 2 (Total 20 marks) Figure 4 below shows a diagrammatic section of the floor of a typical house suspended over a garage. The steel beam shown in section spans 7.2 metres centre to centre of supports. The floor, including an allowance for the self weight of...

I'm working on an assignment about phase diagrams and one of the topics we skim is isomorphous phase diagrams. As a topic its easy to grasp and the copper nickel diagram is a good example, however I was wondering if someone can outline any other isomorphous materials because I would like to use...

Hi everyone! Im developing an application with a physics library. In the application I pre-setted some materials with the following properties, Density, Friction and Restitution Im not sure if this informations are truly trustable, Can you guys just review this for me...

Homework Statement what is the relation between reflectivity, emissivity, and absorptivity for an opaque material? if an opaque material's reflectivity is 0.075 for solar radiation in the visible range and 0.95 for radiation of a heated surface of 80 degrees Celsius in the far infrared...

Sorry if this is the wrong forum, but I figure it is the most relevant since it deal with crystal structures. I'm taking a materials science course currently, and have some confusion on the definition of close packing. Since it seems to represent different things depending on if it is viewed...

Homework Statement Find the capacitance of the capacitor shown in the figure. Asume H << L. http://imageshack.us/a/img39/1935/capacitor.png Homework Equations Capacitance of a plate parallel capacitor with a dielectric material e: eA/H where A denotes the area of the plate, and H...

Does anyone know of any good materials to make pipe out of that can withstand around 200 psig, 250 F and is completely non conductive? Would also be nice if it was durable to external bumps and drops as well. Was thinking carbon fiber but that won't handle high temperature.

Homework Statement I have to do the following practical, but I am unsure of how to calculate one of the variables. We are doing this test and we are given this information to calculate E. I have equations on how to calculate R and I, but I am not sure how to calculate M. It's...

I'm curious about the compatibility of a whipple shield and bremsstrahlung prevention(like that provided by paraffin). Until a short time ago, I was under the impression that bremsstrahlung is only generated when a charged particle collides with a metal. This is apparently not the case. So...

Dear All, I am looking for contact address(es) of university institution(s) where i could send samples for characterization. I work using XRD, EDX, SEM, IS(impedance spectroscopy analyzers-upto GHz frequencies). Also, DTA/DSC/TGA, UV-Vis and NMR, among others, principally. I Work...

Homework Statement Consider an x1:x2 mix of two linear isotropic dielectrics (by volume). x1+x2=1. On large length scales the mixture is homogenous and can be characterized with a dielectric constant ε_mix but on short length scales the material is granular so the dielectric constant is...

I am interested in starting to research into the acoustics of speech and music. In particular I want to analyze the spectral profile of human voice in hopes of finding relationships between it and music. A possible future direction for this research is to improve synthetic speech to mimic...

Hi I'm dbmorpher For my local History fair I am basing my report on the Indutrial Evolution and it's Inventions namely the Steam Engine. I wanted to know if there was an easy way to make a steam engine that was or had... Low cost parts No fuel such as coal or wood No need for complicated...

Hello. I'm conducting some experiments to test for the pressure exerted by a thermally expanding cylinder inside a tube. The cylinder is placed snugly inside the tube, usually with zero to a few 0.001s clearance. The cylinder has a higher coefficient of friction than the tube, therefore we...

I recently graduated from NUST, Pakistan completing my Bachelors in Materials Engineering. I've applied to several industries within and outside Pakistan but so far the response has been disappointing. I've been confused regarding where to start. There are a couple of questions I want to ask...

Homework Statement I'm not sure if this is the right section, but I also posted in the chemistry section. I'm taking a materials engineering class which involves a lot of chemistry. I attached the problem. Homework Equations The Attempt at a Solution Plane A: since the plane...

I had a thermal conductance homework problem where heat flowed through gold, and then silver. Both materials were of the same length and same cross sectional area. The problem mentioned that the energy transfer had reached a steady state, and I found through doing the problem that under these...

Homework Statement Calculate the force of attraction between a Ca2+ and an O2- ion, the centers of which are separated by a distance of 1.25 nm.Homework Equations Attractive energy (E) = -(A/r) *The constant A is equal to (1/(4∏ε0))(Z1e)(Z2e) where ε0 is the permittivity of a vacuum (8.85 x...

Hi, I am trying to figure out how to calculate the permeability constant of a lot of plastics by making solenoid (because that seemed to be the best method of doing so). I am currently using: μ=Ll/((N^2)A) to calculate that constant. Using this method I will only need an induction meter...

Hi, I wanted to ask a question about graduate school, programs, and ask for any advice on what I should do/plan for my future. I'm currently a Senior majoring in Biochemistry (B.S.), minoring in Mathematics, with nearly 160 credit hours and a 3.78 GPA. I have a strong mathematical and chemical...

Hi I was wondering about an issue i thought about while attending a masters thesis dissertation earlier does the material of the plate (not the filling dielectric) affect capacitance (even if in the fringing level) ? Check the attached picture , for a better explanation

Hi everyone. I have the following question: on passivated copper sheets used under high electric fields I found some color patterns I can't really explain. A possible explanation would be that there are some thin layers of material on top of pure copper, for instance the copper dioxide coming...

Two questions here. From real-world problems, I was hoping someone smarter than me could explain the physics behind some issues I was told about. It's been a long time since I looked at an engineering or physics book, so please bear with me. 1) For a 3-phase motor, I was told that someone...

Are materials scientists and engineers in relatively high demand compared to say, electric or mechanical engineers? Which degree would be best if I want to work in the "energy" field? And what kind of energy would each be dealing with?

I've been reading about fluorescence and I understand how the band-gap accounts for reemission of photons at a longer wavelength. However, can a material store a photon, and then given an external energy source reemit at a shorter wavelength? I'm imagining an electrified "glass" that could...

I was seaching mechanics of materials books, but i need them to be tensor based. Any sugestions?

I'm torn between the two options, and I would appreciate it if someone with experience could help me contrast materials science with materials engineering. From what I've heard, materials science ultimately leads towards research, and development of new material. Materials Engineers, on...

Hi all, I'm currently a senior studying chemical engineering. I'll be graduating this December. I am greatly interested in pursuing a PhD in materials science, and I am looking for programs that include an emphasis in computational materials (e.g. simulation of atomic structures). I am...

Hi I am looking for some thin and light heat insulation materials probably in a flat plate form. We intend to install this kind of heat insulation plate underground for separating different utilities. Any suggestion ? Thanks alot.

Hi I am looking for some thin and light heat insulation materials probably in a flat plate form. We intend to install this kind of heat insulation plate underground for separating different utilities. Any suggestion ? Thanks alot.