Materials Definition and 919 Threads

Include in your response an explanation of the relationship between spinning electrons and the direction of the magnetic fields they produce in magnetic and non-magnetic materials.

Hi, I'm doing some research on friction, and I did some tests with 4 different types of floor. Now the first of these four floors is a sport surface (it has a polyurethane top coat), the second one is a floor-tile (with fabric on top), the third one a piece of foam and the fourth a piece of...

Homework Statement A graded steel cylinder AISI 1030 is connected to a wall and loaded with axial forces. http://img542.imageshack.us/img542/3959/fbd1.jpg Given: F = 30 [kN] d1 = 35mm d2 = 20mm Elastic Model: E = 2x105 MPa Safely coeffecient: 2 Yield strength limit: 440...

I could not decide where to post this, it concerns astronomy to a degree but my question mostly involves pressure which I assumed was a physics question mostly so I put it here. My question is that, if were actualy interested in designing a space suit that could survive crushing pressures...

Someone tells me that every objects has its own vibration, such as stone, water ... When bee is flying, the sound of vibration can be heard at different speed, bbbbbbb ... but not all vibration can be heard by us. Does anyone have any suggestions on what kinds of device can measure...

Hello, Ive got what some can call a simple question. When an object is burning, I know the 3 things a fire needs are energy, fuel and oxygen. When the object, let's say a sheet of paper, do the oxygen atoms combine with atoms of the paper and become the ash, soot, and smoke the results? I...

Can radio waves penetrate steel? What about titanium? Maybe a characterization of what they can't penetrate would be more informative? ...Or a way to figure out what materials they can penetrate. Thanks, Jake

Hi, I have searched the web for a graph that shows the ferromagnetic properties of a metal like iron or nickel as they warms up to the Curie temperature - when the metals becomes non-ferromagnetic. I cannot find any good images or graphs that shows this very clear. I have been told that the...

Could someone help me understand the strength of fields that can be produced with piezomagnetism? I have not had much luck with searches for these materials.

Background info: This is for a trebuchet I plan on building. Obviously lighter is better especially for the throwing arm which is why I need your help in figuring out that problem, so I can get it as light as possible without it having even a remote chance of failing. If there's information...

Homework Statement today, my teacher asked us a question. he asked, have you ever wondered why materials are magnetic? why are some materials magnetic and some are not? are the magnetic materials specifically chosen to be magnetic or non magnetic? what makes them magnetic? and my class...

Hi guys, I'm currently doing an assignment which seems to be beyond my knowledge and would like to ask for some helps. There are 2 questions I am currently stuck on: 1] A natural gas analyzes CH4, 80.0 percent and N2, 20.0 percent. It is burned under a boiler and most of the CO2 is scrubbed...

Hello:) I am doing thermal physics at the moment, and am up to the part on specific heat capacity. I know that the equation Q=mc\DeltaT refers to the amount of energy required to raise the temperature by 1 degree celcius, but I am just a bit confused about how the energy is calculated. For...

I'm doing my masters thesis on ewald summation, I am searching for proper study materials for that... what I have is only papers(which you know doesnot explain everything they do!). It would be of great help if you can find me a few sources.. Please help. Thanks.

Hi. Often, when I am a tour guide at the Museum of Glass, Tacoma,WA. glassblowing shop. I get a question for which I don't have a definitive answer. I thought someone might know What is special about glass that enables it to be formed by blowing? Which forces are the major factors in holding...

Hello I am building a casing for Neodymium Magnet. I don't want to shield the power of the magnet in any way, and I want the casing to be strong. What is the best material that i can use? It also has to be transperant. Will plastic effect the magnetic field and by how much. Will the...

I say 'some materials' because it is not true for all. Usually, clothes appear darker when wetted, but I have one pair of trousers that actually goes ligher when water spashes on them, so it is not 'always'.

Ok,first of all ,I'm sorry for any further language barrier things,I study in a non-English speaking university,and I might do a mistake in translating some technical terminology. So,the problem is from mechanics of materials,buckling loads.This subject gives me nightmares as it is,I can barely...

My sister has a question: thanks!

What are the effective mass of conduction band (mc) and valence band (mv) of insulator material Al2O3. Kindly tell me your reference

Homework Statement Electric and magnetic fields in many materials can be analyzed using the same relationships as for fields in vacuum, only substituting relative values of the permittivity and the permeability, ε = κε0 and μ = κmμ0, for their vacuum values, where κ is the dielectric...

Hi, I'm trying to understand what makes materials lossy and how to measure that lossiness - this is for either/or electromagnetics or acoustics. So far, I haven't really found good explanations/resources other than that a complex permittivity can cause loss. However, how do viscosity or...

A bar of length 4m when used as simply supported beam and subjected to a uniform distribution load of 30kN/m over whole span, deflects 15 mm at the center. Determine the crippling loads when it is used as a column with following end conditions. a)both ends pin-jointed b)One end fixed and other...

R at B = 5.0625 R at A = 8.5kN-5.0625kN=3.4375kN x/0.9375=(0.5-x)/4.5625 x=15/176 but moment near x there i get different from both side: from A = 2.431kNm from B = 2.346kNm is there something wrong?

Hello all, I feel somewhat strange posting on this forum because I'm majoring in biology and we're supposed to be the enemies of physics, but I've come across a question that I can't seem to find an answer to; this is actually in regards to independent research. Does instantaneous or prolonged...

Hello all, I'm modelling an office building using Google SketchUp to determine its cooling load during summer. Unfortunately, the default building materials (external walls, floor, roof etc.) seem like they are for residential buildings. Can someone please tell me what are the typical...

Hello everyone, I'm a new member of the Physics Forums, and not a physicist by specialization, so please have mercy :-) I'm a linguist by training, and by profession a writer of fiction and role-playing games. I'm currently in the process of getting my first science-fiction novel...

I'm trying to find notes and material on a course, which, strangely, i can't find anywhere (the course). It's called "Computational Mathematics", and it deals with numerical solutions of ODEs, initial value problems,boundary value problems,reliability,stability and convergence of numerical...

Hello all, I am trying to identify materials having a single dominant charge carrier having extremely low (on the order of 10^15 cm^-3) concentrations. Metals and extrinsically doped semiconductors, while both possessing a single dominant charge carrier (electrons or holes), tend to have...

Say we have an electromagnetic wave propagating inside a dielectric material. Of course physically this material will radiate, due to the little electrons being excited by the wave (their wiggling is also the physical cause of the \epsilon \neq \epsilon_0), and oscillating dipoles radiate. And...

Homework Statement A steel bar and a brass bar, both of 36 mm diameter, are joined at point C to form a compound bar. Neglect the weight of the bars. Determine the displacement (in mm) of point D due to the loading. The forces are PB=54 kN and PD=117 kN at points B and D respectively...

I've seen a lot of talk recently about radiation and radioactive materials. I was wondering what the major issues with storing these materials are and what materials are posing the most risks. Which ones are the biggest hazards? Products that are gases instead of solids/liquids? Ones that...

Types of metals, plastics and others like fiber glass. Also I have another question. How do I calculate how long it takes to heat liquid up with different amounts of energy. Say from -40c, how long does it take to heat oil to 71c with a 120volts. This is bare bones, but I just want to know...

I am writing a multi-region diffusion code. The two regions have different material properties, so the analytical solution shows a discontinuity at the interface between the regions. As can be seen here: The numerical code I am running is (Mathematica): While[converge > .00001...

hi,,, i work in an industry ,of were we produce aluminuim alloy which is rolled out at temperatures of 500 degrees , we are using a fibre glass based material for interleaving (stop metal to metal contact ) which as a tendency of breaking down to a fine powder substance , which then becomes an...

Is it possible to calculate whether or not beta decay from a given beta-source can penetrate a material of a certain thickness? I'm thinking something along the lines of first calculating the average eV of the decay (What do you need to know about the source to do this?), and then looking...

Hi I have 5 different experimental data of a ceramic undergoing compressive stress, and I've graphed them. There are some significant differences among these graphs compared to other materials I've compared (aluminium, pvc etc). Each has multiple fracture points etc...my question is what...

As the title, Anyone know any good readable intro book of material science, especially dealing with electronic materials(semiconductors,etc.)? I am a Physics major in sophomore year.. I took Calc 1-3, linear algebra, ODE and some intro EM and modern physics

Hi everyone, I'm trying to gather some ideas of subjects for an oral presentation in my Optical Properties of Materials class: I'd love to find something pleasant or at least nice to develop (like I heard "how a cameleon changes color?"^^), not too theoretical if possible... And with some...

I would like to ask a few questions. Does a table of refractive indices of materials at rf frequencies (say for TV) exists? Is there a way for me to estimate it for some materials? Are the refractive indices of these materials higher? Will those materials have low absorption losses at these...

Hi, I am trying to understand some more on composite materials and i have a question. Let's say i have two materials and i want to produce a composite from those materials. How can i check if a composite is possible from these materials? I have found an equation on the web but i am newbie on...

I'm interested in coating a coverslip with a thin layer of silver for SERS. I intend to grow a salmonella biofilm on it afterwards and get the spectrum. Does anyone have any experience with SERS and if so can you give me your advice for preparing SERS substrates to adsorb biological materials...

Why are metals colder than other objects at room temperature? Or is my assumption wrong here. Whenever i touch a metal bar in my classroom i find it much more colder than my hand feels in the air. I know that metals have heavy atoms, thus making oscillations of them very slow, frequency...

suppose you had a magnetic rod with a diameter of 1" and around 18 inches long, and the north and south poles are oriented at the ends of the rod. if you stuck the north end of the magnet to a piece of steel would it effect the magnetic pull at the southern end? if the north and south poles...

I still have a long ways to go but it seems like many of the jobs require a master's degree. Due to some past mistakes, I may not be able to maintain my 3.0 that I currently have all the way through until graduation.

Hey guys I'm looking through my Mechanics of Materials book (Hibbeler 8th ed.) and am quite confused at the section on shear and moment diagrams. I thought I grasped it very well in statics but I guess I was wrong. Anyways I am looking at Example 6.4 and it asks for the shear and moment...

I don't understand how exactly ESD mats work. They prevent build up of Electrostatic charge. So any non-wool material would qualify as an ESD mat? Do ESD mats also help discharge an already build up ESD, like a person clothed in sweater and charged up to couple of Kilovolts?

development of microwave technology enhanced the the used of ferroelectric materials. how to relate the growth of grain size with polarization and also effect on resonance frequency.

Homework Statement http://img.waffleimages.com/5b5524d885644e9f1c76a800c4b0701a0606268a/problem6.jpg (The image will not work unless it is copied and pasted into the address bar) I am given this drawing and stress v strain diagram, and am told to find the deflection, ∂, at 4 (the end of...

I have 5 different types of balls made out of different materials, all similar but not identical in weight, and all of the the same size. What is the best mechanism to sort these by weight? I can use any mechanical device to sort these balls, such as seesaws, etc. What is the most efficient way?