Materials Definition and 989 Threads

Homework Statement Suppose you are standing on the edge of a dock and jump straight down. If you land on sand your stopping time is much shorter than if you land on water. Using the impulse-momentum theorem as a guide, determine which one of the following statements is correct: a) In...

Hi, all I have to do a project but I need some guidance. I have to make MATLAB draw bending moment and shear force diagrams of a beam which have to be loaded with a distributed load, a single force, and a single moment. First I have to make MATLAB draw a beam like in the picture.

Recently, I have read a lot about the physics behind negative refraction, super lenses, meta-materials and the like and I think I understood the theory to quite some detail. Negative refraction was predicted first by sowiet physicists around Mandelshtam [1,2], and, a paper by Veselago [3,4]...

You will produce a jar with rectangular base and rectangular sides. aLL OF IT be manufactured in the same material. What size should the jar have on the cost of materials to be as small as possible? The length of the can should be 1.5 times the width. The jar should hold 1 liter. here we got a...

Greetings, I am trying to decide what kind of mortar an pestle to buy. I see they come made of ceramic, glass, granite, marble, and stainless steel. I have eliminated stainless steel because I read metal mortal and pestle can spark and ignite flammable chemicals. Which of the others is the...

1. Calculate the forces in the members FG, GD, and CD of the truss shown in the figure by using the principle of virtual work. All horizontal and vertical members are 1m long 2. I have attached the diagram 3. I can easily calculate this using normal principles, but not understanding how to use...

Hi, I am doing a survey on existing methods of cleaning up radioactive materials for a personal project on cleanup of existing radiated sites. I have done some googling but some things still remain unclear so I'm going to ask you all on the forum. Here are the questions: 1. How are...

Hi, I am having a question about diamagnetism. I understand that ferromagnets realign with external magnetic fields. I know that besides diamagnets like copper, bismuth, that all matter exhibit some diamagnetism to some degree. I wonder though if these paired electron filled orbits of...

I am a senior in high school and have a problem.. I want to pursue a career in nanotechnology, therefore I applied for an undergraduate place in MSE. The problem is that I've recently started reading about quantum physics and the structure of the physics (with theoretical physics) course and I...

Homework Statement Why is there such a large difference between the elastic moduli of metals and polymers? Homework Equations The Attempt at a Solution I am thinking because of the different bonding between metals and polymers. Since metals have metallic bonding and polymers...

Hello, I was wondering if anyone could point me in the direction of some quality materials science resources on the web? I am currently in an intro to materials science and engineering class and have been fascinated by the subject this semester. I was just wondering if there are any "go to"...

I have a 2 year TA offer at UC Irvine for physics (~$18k) where I would focus on Condensed Matter experiment or the chemicals and materials physics program(this program is easier and offers a 10 week summer research program before grad school begins). Degree time is usually 6-7 years. The...

The title pretty much says it all. I want to know if any piezoelectric materials can fully function in constant contact with water. If so, how long a lifetime could be expected and would there be any polluting to the water? Thanks

We are looking at designing a 10" diameter, 48" long payload shroud (Ogive nose cone) for a large hobby rocket. We have done an aeroheating analysis based on the trajectory, so we have the max temp. experienced during ascent at several body points. We want to make the shroud out of composites...

Do such materials exist? If they do, are there materials that go from very high to very low thermal conductivity depending on electrical input?

Please excuse me if this isn't a physics question - I'm not sure where it belongs. Felt, such as this: http://www.ebay.com/itm/Felt-by-the-YARD-Craft-Supplies-36-INCHES-X-36-INCHES-square-100-polyester-/261301533508 And 3mil plastic sheeting, as this...

Hello. I would like to hear of somebody with experience in the area of materials science (theoretical/computational or experimental) the answer to the following question: What kind of Physics knowledge one must have to work in this area. I mean, how much of the basic Physics stuff you must know...

I like using computations/modeling/simulation for many kinds of physical problems, whether it be for molecular dynamics simulations, CFD, DFT to determine the electronic structure and properties of materials, molecular dynamics, etc. I'm not interested in hands-on work as I hated my lab classes...

what materials heat up under pressure and for how long?? I was just wondering are there any two rocks or combination of rocks that when their flat surfaces are pushed together cause heat? If the pressure is very high is that heat quite considerable?? or maybe there are liquids that do the...

Hello all, I am looking for easy to obtain materials, preferably in powder form, with good absorbance at 808nm, 365 nm and 404 nm each (either one material for each wavelength or one for all three).However I can't seem to find absorbance charts. Does anyone have any idea either on which...

Dear experts, I wonder if semi-crystalline plastics can be considered as Mooney-Rivlin materials for an application in the analytic modeling of thin membranes. Any help will be very appreciated! The stored-energy function (W) of a Mooney material model is: W = C1(I1-3) + C2(I2-3)...

Hello all, I'm taking my first actual quantum course this semester. I went over "briefly" some quantum mechanics Fall of 2012 in a Modern Physics course during my sophomore year, currently I'm a junior. To get straight to the point, this course is making me miserable. I had high hopes for...

I intend to take the physics GRE this coming april, and will probably retake it again next year. I want to go to a good grad school, but my gpa isn't stellar (3.5ish), so in order to atone for my sins (so to speak) I want to put a lot of work into getting a stellar grade on the pGRE. However...

Hello all, I have been learning to use FDTD to model light interaction with various materials. I've successfully managed to model light interaction with semiconductors/insulators. However, I've been having trouble understanding how to incorporate metals into this model. The code becomes...

I have a basic question concerning strength and weight of materials. Please forgive me if my question is extraordinarily naive, but I'm an elderly retiree and my education is woefully lacking in this area. Thank you for your patience and understanding. Let us say we have a block of X material...

If I am using radar to determine the distance of an object from my transmission source by reflecting my radio waves off of the surface of the object and recording the time at which they return and, I want to encase my detector to protect it from the elements, how do I select the material with...

I'm hoping to make (or model) these little cells on my own, but I'm not entirely sure how it can be done with household materials. I've seen a few videos of it being done but there's not much on how to create them. Any ideas? Thanks

What are they? I am in pursuit of learning pretty well all of precalculus (algebra, trig, everything!), what are the best learning resources out there? I am studying at home by myself. Thank you, this advice could be life changing.

We all know that hard materials scratch soft materials, and the effectiveness is related to the difference in their Moh's hardness level. My question is whether some minute amount of abrasion occurs on the harder material that is scratching the soft material? If so, is there any mathematical...

Using this godawful textbook (Fundamental of Thermal-Fluid Sciences, Cengel) for Thermodynamics. It's thick as three bibles, has lots of pretty pictures, constantly goes off on tangents, avoids 'advanced' stuff like calculus like the plague and is filled to the brim with problems involving...

Hi everyone, This is my first post here, so go easy on me. :) I am looking towards investigating the properties of plasma antennas, where a plasma is created in a sealed container, and the RF signal is either capacitively or inductively coupled and the transmitted. However, I am wanting...

Can someone please give me a bit of advise. I was dealing with impact toughness of materials today, which I haven't dealt with since uni days. I was involved in charpy testing. I understand the concept of finding the impact toughness from the test [ m x g x (h2 - h1) ]. But what I can't get my...

Interstellar travel is mostly a though experiment at this stage (although NASA will be launching the solar sail SunJammer in a couple of years). My question is a very broad one about what type of materials would be well-suited for structures to support interstellar travel. Any human habitat...

What are the problems that exists in airborne structure/ circuit ? - Electronics

I'm trying to write a very, very simple heat flow simulation program. The idea is an environment space is a grid, with each grid space identical in respect to all other grid spaces (I'm calling a grid space an "element") except temperature. So, they are physically the same except temperature...

I'm working on a problem but I've hit a road block.. Then the cross section of the piece is here: The first part of the problem is to determine Iy, Iz, and Iyz of the member.. I found the y value of the centroid to be 2.8587" and the z value of the centroid to be 1.0734" using the...

Hi I chose a Monte Carlo simulation of the 2D Ising model as my Computational Physics course project. Unfortunately, I ran intro problems when formulating the exact problem since my professor probably wants me to simulate a real life material and extract magnetization curve M(T,H) out of it...

like autoignition temperature... materails will ignite spontaneous in (low pressure) with concentration oxgen and less heat temperature...

What shielding materials are best choices for reducing dose from: Neutrons: Gamma rays: Electrons: HCP: (heavy charged particles) I know, good neutron shields can be hydrogen (can be explosive though) or concrete, beta/electrons is a combo of low Z-material to block e- then high...

While thinking about the recent-ish developments in meta materials for 'cloaking' systems, a thought struck me: could a meta material or combination of meta materials (probably of a somewhat more advanced state than they currently are) be used as a form of shielding from cosmic rays of various...

I'm going to try to make this as coherent as possible. I'll start with the fundamental question first: Would it be reasonable to take classes outside the Physics undergrad curriculum/required courses that my university doesn't require, but others do? Here's the nitty-gritty: I am...

Homework Statement A. determine the deflection at point A in the X and Y direction. B. determine the maximum normal stress in the beam C. determine the maximum shear stress in the beam Homework Equations δ=(PL/EA) (possibly?) δt=αΔτL d2v/dx2 = M/EI dM/dx = V δab=δx*cosθ +...

Hello, Imagine I have an infinite wire with a DC current. Around it there two rings of ferro-magnetic material, not far from each other. Does changing the mu_r of one of the first ring, changes the magnetic field in the second ring? - If I consider just Ampére law (macroscopic...

Homework Statement A rigid weightless horizontal beam is hinged at a wall and is supported by two rods. The beam has a 8000 pound load applied at the end. Calculate the tension in each rod. The left rod is made of brass and has diameter of 1.25" and the right rod is made of aluminum and has a...

Where can i get the theoretical value of MFI for common polymeric materials such as PP, PE, PS, PMMA...as reference?

Hi, I'm using an induction coil to heat up an electrically conductive material within the coil. However, I'm worried that adjacent electrically conductive materials, which are not within the coil will also have see a heating effect, due to induction not thermal transfer. I want to avoid this as...

Hello, I'm studying machanics of materials.. I'm at the chapter that handles the angle of twist in shafts. There's one exercise that I get the most part of, but there's just a tiny part of it that I don't get! here's the exercise...

Homework Statement I have a project for my Materials Science and Engineering class and we have were given 4 unknown materials and we have to determine which kind of materials they are. We have to come up with our own experiments. As of now, I've done the Rockwell hardness test, electrical...

Hello everyone, I'm an undergraduate senior majoring in physics and math, with plans to go to grad school next year. I have two questions for you all: 1) for someone interested in nanotechnology, biotechnology, and physics, is materials science a good PhD to pursue? 2) If so, are there any...

Would a piezoelectric crystal create a negative voltage if held within a vacuum? Perhaps it's my misunderstanding of the materials properties, but it seems that if there is zero net output within the "creation"(0) atmosphere, and any slight elastic deformation shows itself in the form of an...