Material Definition and 1000 Threads

A problem involving E, D & P. I have the answer but not sure why for the P bit.A bit of clarification if someone could, please. A thick sheet of polystyrene, of relative permittivity ε = 2.5, is placed normal to a uniform electric field of magnitude 500Vm−1 in air. Find the magnitudes of...

Hi, I wonder if there is a material or paint/dye that would change color when exposed to air? Ideally, it should have the following properties: White-to-black, black-to-white, or any other high contrast color transition (e.g, yellow-to-brown would work too) Works under normal conditions...

I'm looking to create a very small expandable package to be filled with a very small amount of a volatile material at a low temperature. I'm looking to fill this package somewhere around 0.2mL of this material (propane, butane, etc) so that when exposed to room temperature, the package expands...

I beg forgiveness if this should be in chemistry; to me it seems more of a physics problem. This summer I had two Polyethylene terephthalate (PETE) spice bottles deform due to the sun shining on the clear plastic tub, Polypropylene(PP) in which they were stored. The first time the big tub was...

Hello experts, I would be glad if anyone could help me find out some basic beginners materials on ORBITAL MECHANICS. I am looking for ones that would help me understand the practical and technical aspects of launching a satellite, maintaining it in an orbit, changing orbits, results of...

I've been thinking about the building-design simulation, and am hoping that someone can point me toward more complete treatises/references, than this hobbyist impression. I'm trying to develop a mathematical outline of simulated deformation physics, with the hope of eventually creating a...

I'm building a linear actuator and I don't have much experience with magnetic circuits... A rough sketch of what I'm building is attached. I'm trying to determine if the materials I'm using for the shaft and shaft collar will have a detrimental effect on overall force output. Right now, my...

I have reviewed the material covered during my sophomore year and although it does not seem like a joke freshman year was, it shouldn't be very challenging either, it includes introductions to modern physics and waves with 2 labs and mathematically linear algebra, diffyq and vector calc. If I...

Consider a piece of a deformable material with mass m and constant density \rho . To what shape should we deform it so that its gravitational field is maximum in a given point?

Hey guys, I'm having trouble with this problem set I'm working on at the moment. I'd appreciate some help with this question: (I'm only asking about number two, not one. Thanks.) The lack of a top is accounted for in the formula for the box's surface area, which should be: SA= L^2 +4HL And...

Why is it that in bulk matter , though molecules are closely packed electrons are no longer attached to individual nuclei It is mentioned in 6th line of 3.3

Hi all, I have an idea for a project whereby I there would be an electromagnet pulling on a metal weight through wood. So: Electromagnet -> Wood -> Metal The basic idea is to stick things to wood with electromagnets. Can anyone recommend a material that could be bonded to the Metal what...

Is there any such material which can be made to conduct from a non conducting state by external means like shining a light or any other EM wavelenght on it or other means , that could alter the material ohmic resistance to electric current

I'm developing a small product, And I need a material ( maybe a plastic ) for a metal part slide through. The material will have a hole and the metal part will go through but will have to be very tight hole and I'm afraid when making production obviously the measurements maybe be different and...

I was wondering how I would go about working out the energy required to cut a material (e.g. stone or steel) if given a volume, and all the necessary values pertaining to that specific material? For example, how would I work out the amount of energy required to cut a steel block of dimensions...

I am undergoing internship in an motorcycle company (OEM) and would like to know if there are any ebooks about motorcycle parts, manufacturing processes, general manufacturing practices, Engine, vehicle assembly operations and stuff like these?

Hi guys, I'm new to this forum and I am not so sure where to post my question.. My first question, is graphite capable on detecting vibration? I'm currently doing my Final Year Project, trying to investigate on graphite compound. I using the graphite from the pencil lead and sketch it on a...

If I were to strike an arc between a copper cathode and a tungsten anode would copper be deposited on the anode? If so how could I calculate deposition rate? I know this works in electroplating but will it work through air or another gas?

I'm attempting to build an alternating current electromagnetic coil and want to maximize its potential field. My initial query was to find the very best core material for the electromagnet. I found an older post (2005) on the subject and saw some very interesting answers there. Being new here...

Homework Statement I think that the image is clear. There isn't friction, not the material point with wedge, not the wedge with the floor. At time t=0 the material point start to move, I need to find the final speed of the two objects at time t\rightarrow\infty. Homework Equations...

hi, I am running some scientific experiments, and I need a sheet of materials that is extremely good conductor of heat in z axis (through its thickness), I mean it is a good longitudinal heat conductor. I have been doing some researches and some people told me Ni and Mo foils are good at 90...

I'm building a 6'x12' steel platform that will be 3' elevated from the ground. How can I determine what load bearing weight will be if I use 2" Square Tubing, 1/4" wall thickness and then use 1/4" angle iron for the platform structure? I was going to use 2" Sq tube, 3/8" thick, but most local...

For which reason some of materials have direct gap and the other have indirect gap? In other words, what we have to do to convert a direct gap material to indirect one?

Hi all, I want to learn Quantum Transport materials . I would like to know some good material to start with and also I want to learn NEGF formalism. please suggest me some good books that teach from fundamentals in these areas.. Thank you ...!

Hello. There is an adapter here in our workshop for milling holder BT shanks (that converts for example BT-60 to BT-40). We have decided to build a new one according to the sample. The surface hardness is about 60 HRC, we tested the material for analysis and it was 1.8519 (31CrMov9)...

I can understand the derivation of bulk modulus (K) for isotropic material. However I have difficulty to do the same for anisotropic material. to start with we have the definition: mean_stress = K * (strain_xx+strain_yy+strain_zz) My question is for anisotropic material: Is mean_stress =...

Homework Statement Determine the Strain Rate for a Material Fiber in the direction of the surface normal. The Velocity Field is V=((4y-3x)i+(5x+3y)j) ft/s http://puu.sh/9hQ7Q/2bda80620f.jpg is the picture which describes a steady, planar flow where i and j are unit vectors. Homework...

I'm an upcoming senior at a small, private college that has a good reputation for science. My major is in physics with a minor in mathematics, but I originally was in biochemistry. My freshman year didn't go so well (2.6 GPA), and I ended up switching to physics my sophomore year. I have a low...

I am trying to figure out what kind of material would be best used in order to transport water through a material that would be the same size/shape/diameter of a conventional pipe inside a home running water. The idea is that the water running through the pipe would be at a temperature of...

So I want to fire a magnetic ball through a solenoid coil but want to know if core material can enhance the performance. Would wire wrapped around soft Iron tube core work better then say a thin copper tube? The aim is to increase efficiency so less power needs to be used to fire the magnetic...

Hi, So I was thinking about corrosion and I came across this structure: Do you think the inner metal/alloy that is corroding is steel? Also, what do you think the outer layer (in white) is? perhaps the metal is just coated with paint to avoid corrosion? Finally, what type of corrosion do...

Hi, I am a student looking for a material for a project at school. I am currently studying mechanical engineering so the chemistry and materials aspect is a bit over my head. We're working on a concept to develop a more ergonomic chair and would like to find a material that would be...

Hi there! Im new to this forum so pardon me if this is the wrong place to post my question. Basically, I have an idea with regards to doing some modification to phone screens. However, there is no such technology (yet) for this and I have zero knowledge and background pertaining to...

Here is an excerpt from my textbook: "Ordinarily, this charge would simultaneously generate so large an electric force as to swamp the magnetic one. But if we arrange to keep the wire neutral, by embedding in it equal amount of opposite charge at rest, the electric field cancels out, leaving...

What is the work done on a paramagnetic? I have seen both of the following: \hat{d}w = -MdB \hat{d}w = -BdM Where B is magnetic field and M is magnetisation Am I missing something here or are these two completely opposite? My textbook says that -MdB is the work done but I am sure I...

Not sure if this is the right forum at all but maybe you guys might have something. Basically, I need to stick and object that is thrown to another stationary object. But the object thrown needs to be able to be taken off. So far there is velcro to velcro and we have an object which is...

I'm double majoring in Chemistry / Materials Science & Engineering undergrad and I'm wandering yes it has engineering in the title but it also has Science as well. Is this engineering say more theory based than others? I read descriptions saying it designs metal alloys and everything like...

Heat transfer -- aeroheating and material thickness I'm trying to size the thickness of a shroud to encapsulate a payload on a small rocket. We're using carbon fiber pre-preg (k=6.83 W/m-K) and (per the aeroheating analysis based on the trajectory) the max heat rate is 908 kW/m^2. The...

Homework Statement An EM wave with frequency 87Mhz travels in an insulating ferromagnetic material with \mu_0 \mu_r = 1000 and \epsilon_0 \epsilon_r = 10 - What is the speed of the EM wave in the material. Homework Equations v=(\sqrt{\mu_0 \mu_r \epsilon_0 \epsilon_r})^{-1} The Attempt at a...

hi,could some one please help me to understand how to find the density of water using a specific gravity bottle?and also a solid material..:cry: many thanks.

What are the best online introductory resources for Loop Quantum Gravity? I've never felt more out of my depth than when listening to Rovelli speak on the subject.

Hey guys! So I am taking an algebra class at a college but I am still in high school. And I have been really struggling with it. This is one of the problems that has me quite confused: A can in the shape of a right circular cylinder is required to have a volume of 500 cubic centimeters. The...

Homework Statement Question 2. Tetraethyl lead was used in early model cars to help reduce engine knocking, boost octane ratings, and help with wear and tear on valveseats within the motor. In Australia, our petrol contained lead between approximately 1950 and 2002. Consider the impact of...

I work in the IT department for a small mining company and recently discovered during some product research that one can determine the weight of material in the bucket when given the following: The angle of the boom The angle of the arm The orientation of the chassis The hydraulic pressure...

Homework Statement Question 1. An industry uses a long drainage ditch to break down their wastes and in particular to remove the odour. The waste travels along the ditch at a velocity of 0.5 m/h. The odour is reduced as a first order reaction with a reaction constant of k=0.30 day-1 The...

Hi all, I'm david from indonesia. Sory for my english. Can you help me to found a chemical that I can use to cleaning printed picture on plastic material? This is for recycling, means in big volume... Thanks before

capacitors don't require a "dielectric" material they? whenever i hear about capacitors, i hear about the 'dielectric' material, but a dielectric material as opposed to a non-dielectric insulator just means that the material is polarizable. but polarizability only affects the field strength...

I am looking for a commonly available, non toxic material (i.e. on the market today for a relatively low price) that exhibits reasonable expansion and contraction in size when electricity is applied. This could be a gas, liquid, easily workable solid but ideally it would be a fabric or flexible...

Should I use Quantum ESPRESSO or Material Studio? I want to compute some properties in Material

Special rubber tires are made slightly conducting, in aircrafts, to enable them to pass on charge (produced by friction) to the ground, as too much charge may result in a spark and hence cause a fire. This is apparently the same reason why some vehicles usually have metallic ropes touching the...