Materials Definition and 919 Threads

My question stems from the visual perception of color. First I'd like to clarify what we're seeing. When we see that a material is a certain color does this mean that it's constitute atoms are continuously absorbing certain wave lengths/energy levels of light and blocking out/bouncing the left...

I was reading through my mechanics of materials book (Mechanics of Materials 8th ed. R.C. Hibbler) learning about stress and came across example 1.6 pg. 28. while most of the example makes sense the last bit of part b) confused me. I am unsure as to why for Pcd he only showed the 22 kN force...

Hi I'm not a physicist but I'm looking for a simple way to test the hardness of different materials. I need to do a demonstration and collect results with a science class, the task sheet that accompanies the lesson says to place a cloth over the materials and hit them with a hammer. I would...

Which of the following materials have activity Optical ? i know it must have an Chiral molecule,but still i am not know in this list who have it. thanks for help.

Does anyone have any good online reference sources that derive the basic equations from Mechanics of Materials such as angular deflection of beams under torsion, stress on cross section due to moments, etc. all the easy basic stuff. I took those classes a long time ago and I don't remember...

I have a simple question that I cannot find a compelling answer for. If I expend (let's say) 100 kJ bending a steel bar into a right angle, where did the energy go? Some will obviously be expended as noise and heat. Will the rest be expended in the plastic deformation of the bar? No useful...

I have two materials that I have to decide who has a higher boiling point C2H5OH-CH3OH this is the First duo here i have no idea how to know. and i have The second pair:CH3CH2CH2CH2OH-CH3OCH2CH2CH3 is will be correct if i will say that CH3CH2CH2CH2OH have the higher boiling point then...

Homework Statement If you have two materials of equal length and radius and then you join them together. Material 1 young's modulus = y1 material 2 young's modulus = y2 Homework Equations F/a = y Lchange / Lo The Attempt at a Solution Given they are of the same length and radius...

I have to write an empirical formula for these ionic materials: Al N Sr I so i know that Al gives 3 electrons and N will get 3 electrons. to make them to be neutral so the empirical formula of Al and N need to look like this AlN? and for Sr and I i know Sr gives electrons and I get 1 so...

If I take a spring and move one end at a different velocity then the other tension will build in the spring and when released it will return to its natural shape. What If I take an object and put one end at the edge of a centrifuge and the other at the center. Acceleration and velocity will...

Hi, Can someone with a bachelor in physics, masters in ss physics, go into materials science r & d? Thanks, miss fangula

Hi guys, I just finished my BSc in physics, and I’d really appreciate any advice on deciding between Electrical Engineering and Materials Science & Engineering for my masters. Anyway my argument goes as follows: Interests? My interests lie in nanotechnology, super/semiconductors, green...

I'm a math major, but I really want to learn about general relativity (the 'real' GR, not the watered-down version that gets into popular science books) on my own. I'm not in any rush to learn it--i.e., I'm willing to work through a big tome like Gravitation over the course of, say, the next...

Can Microwave radiation penetrates building materials? I'm living within 120 meters from a mobile phone base station and I'm concerned with possible health effects from it .

Hello Everyone, I'm interested in designing my own custom electric motor for some experiments and I am trying to do some research on some of the various laminated steel materials available. I have a decent working knowledge of general magnetic material properties, saturation characteristics...

Hi everyone I'm having a bit of trouble solving this question. If anyone can help that would be awesome Homework Statement Rank the materials in the diagram according to their refractive indices from greatest to smallest (see attachment) The attempt at a solution The greater the...

a chemistry lab. What materials do I need if I'm going to be doing a metal + acid (rate of reaction) lab?

Homework Statement Show that the polarization of a material is P=Nqx where x is the displacement between the center of the electron cloud and the atomic nucleus. Homework Equations P=Nqx is given and I went ahead and subbed (q/m) * E[1/(w0^2 - w^2)] for x. The Attempt at a Solution...

Hi, How can I measure the capacitance of a capacitor, using the following: a battery, a digital voltmeter (which records voltage as a function of time), a digital ammeter (which records current as a function of time), an industrial capacitor, two copper plates, and several...

Hello, I'm puzzling over the likelihood of building a dry-running air motor for 25khrs @5-20kRPM. I'm considering whether a small gear pump arrangement would doe the job - it only needs to output 6 shaft watts, but I'm concerned about wear. Standard gears are avalable in steel and...

I've heard a lot of good things about the field of materials science, and the work being done seems really cool to me. But I'm wondering what a working materials scientist actually does. Does it use a lot of math and physics? Is it mostly lab work? Is it more qualitative? The reason I ask...

Example: Take a hydrogen atom and make it a carbon atom. Can we do it with our current technology? If so, how do they do it?

Homework Statement The bars in the truss each have a cross sectional area of 1.2in^2. If the maximum axial stress in any bar is not to exceed 25ksi, determine the maximum magnitude of P of the loads that can be applied to the truss. Determine the elongation of each member. E=29,000 ksi...

Would titanium and copper make a better Earth battery than iron and copper? What will the voltage and current difference be between the two?

Dear Kind and Knowledgeable Contributors, I am a graduate student in my first year debating between completing the rest of my PhD. program in Chemical Engineering or Materials Science and Engineering. My university allows me to switch into either field. I believe I am equally capable in...

Homework Statement A circular shaft AB has a torque T acting at the middle of the shaft, defined as plane C. Shaft end A is fixed while shaft end B is free to rotate (mounted in a thrust bearing). Finding the twist angle from A to C is not difficult, but the question requires that the twist...

Homework Statement A plastic gutter is designed to catch water at the edge of a roof. Manufacturers need to minimise the amount of material used to make their product. What is the best cross-section for a gutter? In this case, a circle. Homework Equations None, asside from...

Guys, I have two objects here, need to know what are they and the processes they go thru to manufacture. Thanks, shubhash

Is specialization in radiation shielding and reactor/reactant materials a valid area of specialization? I am just worried if the two areas are too broad or different to name as my area of specialization. I ask this because I am trying to answer my applications for area of specialization and I...

http://spectrum.ieee.org/nanoclast/semiconductors/nanotechnology/nanostructured-metamaterial-enables-invisibility-cloak?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+IeeeSpectrum+%28IEEE+Spectrum%29 "We can even have amplification of light instead of its absorption. Here, for the...

Hi, I am not a physicist. I am trying to understand something about the behaviour of materials for computer graphics applications. I am trying to get an intuitive understanding of refraction. As far as I understand it - and please correct me if I am wrong - lightwave's phase velocity is...

I am currently designing a small humanoid. What are the possible materials for the body? I would like the robot to be light and economical.

I have a number of materials all mixed together in a beaker, my task is to extract each material individually, and get the weight of those materials. The materials in the beaker are: -Olive Oil -Copper 'bits' about the size of rice grains -Beach Sand -Iron Filings -Gravel - pebbles...

i understand that light 'slows down' in a refractive material when passing through it, but is this an actual drop in speed, or is the light absorbed and re-emmiited etc, so that its actual velocity does not decrease, merely the appearence of it. does time slow down inside optical material?

Hello, I am currently getting ready to start applying Ph. D. programs, but I am unsure whether I want to continue with physics or materials science (I will graduate with degrees in both physics and materials science). I am wondering whether career options will be better for a physicist or...

Could some one explain, or give me a pointer to a good explanation, of how the nine constants that are often used to define orthotropic materials are determined. I understand what E is in each direction. I understand poisson ratio. I sort of understand G. (I understand it as the E...

I have found plenty of study materials, notes and links on Classical Mechanics and Quantum Mechanics. However I could not found any forum on this site that provides study materials of solid state physics. So please if you have got the link, please post it in here.

Is the only way to find a material's or compound's behavior at the nano scale through experiment or can we deduce its characteristics through some other way or theories?

I am about to talk to a prototype company and need some advice on O ring, friction and seals. I am creating a device that works on slight water pressure differential. I have a piston like structure that is cylindrical and there will be an o ring inside the cylinder. The gas/liquid that the o...

Remember those executive toys that were popular in the '80s? You have a steel ball on the end of a thin rod hitting another steel ball that is stationary. As near as we can see, the target ball gets all the momentum of the moving ball, and the moving ball stops dead - close to 100% transfer. But...

Hi everybody, I have this simple question. ¿Where can I find the covariant maxwell equations in materials?. I've already one and proved they correctly represent the non-homogene maxwell equations, is this one \partial_{\nu}F^{\nu\mu}+\Pi^{\mu\nu}A_{\nu}=J^{\mu}_{libre} with the tensor...

If I would like to do research in materials having to do with nuclear radiation and nuclear physics, what type of degree path should I follow?

Homework Statement A shaft fixed on both ends is shown below. It is made of a steel tube, which is bonded to a brass core. A torque T_D is applied at location shown. The tube is fixed at both ends. [PLAIN]http://img202.imageshack.us/img202/2940/problem2eb.jpg Show that the fraction of...

Homework Statement The magnesium allow tube (AM1004-T61) AB is capped with a rigid plate. The gap between E and end C of 6061-T6 alluminum alloy solid circular rod CD is d[m] when the temperature is T_1 degrees celcius. [PLAIN]http://img27.imageshack.us/img27/8867/problemwn.jpg The...

Homework Statement 1) Why, in general, do brittle materials not achieve their theoretical tensile strengths? 2) Why, in general, do ductile materials not achieve their theoretical shear strengths? Homework Equations None needed. Wordy answer. The Attempt at a Solution...

I´m trying to find approx. numbers or formulas for a submarine like structure to mantain a constant volume. For a given volume, which materials and to what thickness should the container be?

Hey, Just wondering how to explain the yield point run-off for low carbon steel. Why does LCS have an upper yield point, followed directly by a lower yield point? Thanks, -Spoon

Hello. I'm interested intaking a cloud formed of activated carbon particles and particulates of some other substance to produce static electricity similar to that formed in a cumulonimbus cloud. The means of containing this experiment is another matter. I understand that when "opposite...

what is exact difference btwn ISOTROPIC and HOMOGENEOUS materials (kindly don't tell definition of those things)

I wonder if there is any theoretical knowledge how to predict which atoms will decay first in given radioactive substance? I was asking about this in school and teacher said it is not possible to predict this...i doubt this process is random... Thanks