Material Definition and 1000 Threads

Hi, I am new to this forum to ask for advice: I have shown experimentally that a very well known material offers great advantages when used as substitute for another material in a range of devices. It is not obvious to use this material and because it requires some very specific knowledge...

I am working on a project and I need to find out what kind of core material this is... Unfortuantely I cannot ask the person who had it because they no longer have it. I don't think it's ferrite, the thickness is about .125", and the permeability is around 700-1000. It had several coils on...

Hello all, I'm working on a personal design problem and am stuck. I am trying to figure out "how to figure out" what material I would need. I hope that makes sense.For example: I have light of 400nm and I want to change it to light of 500nm. I figured I could just pass the light through a...

Hi I am having a lot of trouble with this problem. I don't actually know where to begin. A box with a square base and open top must have a volume of 62,500 cm3. Find the dimensions of the box that minimize the amount of material used. Need to find: sides of base cm height...

Hey guys so I'm enrolled in a Mechatronics/Robotics course next semester and it's notorious for being one of the hardest classes that I can take. I'm a little worried about the difficulty of the class, but I think I can get through it haha. Anyway, I was wondering if there were any online...

Okay guys, I have a question and I am sure the answer is stupidly obvious but I can't seem to find a equation explaining it. I want to know the max possible voltage of the capacitor based on the distance between the plates, the Area of the plates, and the resistance of the material between the...

This is a question about something in Sean Carrol's Spacetime and Geometry text. I'll quote here: " ... current estimates of the maximum possible neutron-star mass are around 3-4 Ms, the Oppenheimer-Volkofflimit. Since a fluid of neutrons is the densest material we know about (apart from...

Homework Statement Show that for N-type material the carrier concentration is roughly the donor atom concentration. Explain why a N-type material is conducting at much lower temperature then a intrinsic semiconductor Homework Equations maybe no equations are needed here The...

My professors skipped both chapter 11 & 12, Equilibrium & Elasticity and Fluid Mechanics. I'm worried that I will need to know these chapters for later classes or for the GRE. Has your professor skipped material in your class?

Neutron stars are held together by extremely strong gravitational force. What would happen to a chunk of the star if it had been removed and left to stand alone? Same question for a chunk of a white dwarf?

I have three books in hand and would like information about how useful they are, or if things have changed that makes them too out of date. From Atoms To Quarks; 1980, James S. Trefil Mirror Matter; 1988, Robert L Forward & Joel Davis Atom; 1992, Isaac Asimov I'm an entry level study...

Hi, I was wondering if anone knew what an internal CD or DVD drive case is most commonly made of. I was hoping to use it to do some welding so am hoping it is steet but not sure. Cheers

How can I find the induced current density by EM wave in a material? Should I have ma = Fbinding + Fdriving + Fdamping like treating it as a spring? Then the current density should be charge density of the material x velocity (ρv), isn't it? Is there any condition the EM wave cannot...

Homework Statement A small material has quantum oscillator energy levels 2E-23 J apart. Suppose the material has a total energy of 34E-23 J and contains 5 atoms. Find the entropy of the material. Homework Equations Entropy = (Boltzmann's constant)*ln(multiplicity) Multiplicity = (q +...

What material is suitable in windows for hard X-rays? What material would you choose as reflective coating of X-rays mirrors for radiation at 200 eV? Why?

Hello, there's something that's been bugging me for quite some time now, and i hope anyone can enlighten me on this. So i'll get straight to the point. Can heat treatment be used to make a material softer? In normalising, you can say that the longer the time given for the subject to...

Hi everyone, So, I'm currently in my second year (undergrad) of university studying nanoscience/physics in Canada. I try to think about my future career fairly often, so that I can do my best to make good decisions. However, I'm beginning to get the feeling that I'm not truly "mastering" the...

I have a question about source hardening: what is the reason for a decrease on the yield strength in the case of the 1-(Un-irradiated) Body centre cubic (bcc) 2- (irradiated) face centre cubic (fcc)

Calculating wavelength in a media Hi Trying to get how to calculate the wavelength of an electromagnetic wave in a media and I am getting confused about the permittivity. I know the formula: vphase = c/(sqrt(εr*μr)) where vphase is the phase velocity. c is the speed of light in a...

Homework Statement A toroidal shaped magnetic material of radius, a, and cross sectional radius R has a small transverse gap cut into it of length l. The toroid is uniformly overwound with a coil of N loops carrying a current I. Show that for a ferromagnetic material the field in the gap is...

I'm trying to get a value of the C0 capacitor of some piezoelectric material I'm working with right now. My only problem is: I don't get electronics at all ^^'. So far I have asked some other people who do get it, but there were going way to fast and are really busy...So I was hoping you could...

Homework Statement Homework Equations Working at a rate of 1.204 x 10^22 fissions/s, what fraction of that 70 kg mass of Uranium will be fissioned during the 550 days of fuel installation? (Fuel rods are replaced appx. every year and a half) The Attempt at a Solution 1.20x10^22...

Hello guys, nice to meet you all. It's kinda awkward since I'm new here and also just a freshmen in my university :) Anyway, I'm conducting a study about the LED components, whom I've already known it is consist of aluminium and Gallium Arsenide (GaAs) or Gallium Phosphide (GaP) or Gallium...

Hi all, This is not really a homework problem, more of a 'what-if' scenario but I'm not sure which section to put it in. For a science project we have been asked to look at material properites and come up with a project (which will have a presentation :eek: but that's another story). I'm looking...

I looking to make my own changing table to travel with. Want hard plastic material, non toxic that can hold baby weight. Any ideas?

I have to write a small paper on quasicrystals... anyone know where I can find free-access books and scientific journal papers on this topic?

Hi, In our chemical company, the pipe spec for check valves prescribes stellited material for disc and seat. Now, suppliers are having a hard time meeting this specification. Are there other materials with comparable properties that are more commonly used? Mostly suppliers offer SS (eg...

As light moves through a dense material, it would interact with the atoms. Would the light lose energy, on average, in the process? As a result, would we observe a red-shift as it moves through? If so, what is the relationship between the amount of red-shift (energy lost) to the distance of...

Hi everybody, I am getting confused by a very simple problem: let's take an infinite sheet electrically charged with a surface density σ. Because the sheet is infinite, we can first determine that the electrical field on both side contains only components normal to the sheet. If the plate is...

Hi, I am a biomechanist looking into Achilles tendon injuries. I was at a conference the other day and they were talking about using tendons for ACL reconstructions and about tubularising tendons. This got me thinking. Is there a certain conformation of fibres that is stronger than others...

Lattice Constant: 7.956A – 7.936A Density: 3.696 – 3.691 g/cc Form: Polycrystalline Melting Point: 2150°C Young's Modulus: 46.9x106 psi Shear Modulus: 18.9x106 psi Poisson's Ratio: 0.24 Hardness: 1850 Kg/mm2 (Knoop Indentation, 200g load) Fracture Toughness: 2.0 MPa-m1/2...

hi, i'm doing a project on development of ceramic nozzle. can somebody help me by giving some information regarding the most suitable type of ceramics that have the good wear resistance and high melting point. thanks.

((Not certain this is the right place)) Hi guys, Currently I'm voluntarily undertaking a project qualification and have decided to write a report on Nuclear Physics and how it could be used as an energy source in the future. I already know quite a bit about this topic but was wondering if...

First of all, i would like to appologise if there is already a topic related to this on which i could have posted. I was not able to find it but also only skimmed through the search results. Mathematics has not been one of strong points. In middle school i struggled with it - i didn't spend any...

Here is the problem: The electron concentration in a region of silicon depends linearly on depth with concentration of 5x10^15 cm^-3 at surface (x=0) and 10^15 cm^-3 at depth of x=500nm. If the vertical electron current density in this region is constant at Jn=100 A/cm^2, calculate the...

Hello PF'ers, a friend and I are sharing an apartment for the school year and we had the idea to make one of our living room walls into a giant whiteboard. I know you can buy rolls of the material to write on (doesn't have to be magnetic), but I'm not sure where to find it. I called the local...

I'm looking for a sheet shaped material, maybe 12" by 12" and 1/4 inch thick, that can be used as a seal to keep air out, so it needs to not allow air to pass through it and it has to be a soft material that can compress, but not compress or bend too much. I was thinking something like foam...

If I had an input of 4KW with Material S/S 304 Density(0.29 lbs/in3) Specific Heat(0.12 BTU/lb/°F) What temperature would the S/S level off at when the 4KW is inputted?? If I am missing any info to help solve this let me know...

We have 3 interstage coolers for a Synthesis gas compressor.Synthesis gas is mostly H2 & N2 with small Ar & CH4.Tube side fluid is water & shell side fluid is Syn.gas.The heat exchangers are made of carbon steel.Now due to corrosion in tube to tubesheet joint we like to use SS for tubes.But our...

So my mother buried her cat 5 years ago this month. I remember I wasn't home back then and it was a hard time. Yesterday we were talking about this and she asked me if I think the body is completely gone, and I said of course until she mentioned she put the cat in a plastic bag before buring it...

If you wanted to calculate the pressure on the shell of an airtight enclosed concentric or asymmetrical/symetrical object, do you simply need the surface area of the object and then divide it into the applied force? 1. So if you apply 50Newtons onto a grounded football for example,it would...

I'm not certain if the General Physics section of this forum is the place where this question will receive any attention, but here's to hoping! I am trying to identify a way in which one could accurately calculate which compound or element would serve as the ideally effective material for a...

Homework Statement In an experiment we were given a broken piece of alluminium that was (before broken) 50mm long. Then we measured it and found the elongation. From this it is pretty easy to calculate the strain. What does this actually tell me about the material though?. Actual Question...

What happens to the ions that are released from the material after e- are released? How come the material doesn't completely degrade?

Hi, I am a recent grad with a BSEE and I will be taking an exam for a job. The exam will consist of the following: RF Microwave Devices, Digital Devices, DC Electronic Theory, Electronic Measurements, Electronic Math, AC Electronic Theory , and Active Devices, I have knowledge of...

I am self-studying "Physics" (Volume 3) by Halliday, Resnick and Krane, and would like to ask some questions regarding the following example given in the book (with solution). I will copy the entire example here, with solution (translated from Portuguese, because I am using a Portuguese...

Homework Statement So today in class we did a lab where we calculated the stopping voltage of lights of different wavelengths. We did this experimentally. I have the wavelength, frequency, and stopping voltage of four different lights. I need to calculate the work function of the material, and...

Hello. This is my first post here and I come shamelessly looking for help. I'm an Electronic Engineer and have an idea for an invention but do not know if the type of material that is needed exists, the only one I can think of so far is Bread dough. Anyway, what is needed is something...

Can anyone suggest me good books on 'C/C ++ & assembly mixed programming' for embedded system coding. I am trying to gain expertise in mixed C/C++ & assembly mixed programming for writing embedded system codes. I am fairly new to mixed programming. I know C/C++ and assembly languages. Now, I...

I am building a model rigid airship, and in order to maintain it's structure I used a balsa frame. Unfortunately this weighs a fair bit and can take up to half of the lift generated from the light gas, and it is not particularly strong. Since I use polyurethane for the outer skin, I am...