The study of how the properties of matter arise from its structure at all scales and of how processing can be used to modify those properties (often in pursuit of a specific application).

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11
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4answers
2k views

Are there limits for the speed of sound? A maximum or a minimum only?

The speed of sound in materials of various states of matter differs a lot. But does it have fundamental limits? Is there a maximal possible speed of sound? Is there a minimal possible speed of ...
1
vote
1answer
25 views

Gough-Joule effect in rubber band

When a stretched rubber band is heated, surprisingly, its tension will increase. What is the physics behind this?! Another thing. The Entropic spring model says, for a good specimen, that the ...
1
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0answers
27 views

Why does not the optical fiber break? [duplicate]

Glass is a very fragile object. So why does not the optical fiber break? Everytime I take them, I am worried about this problem.
0
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0answers
20 views

How are lattice parameters determined from reciprocal space maps?

It seems that the papers speak of reciprocal space maps with very high praise because of its ability to study strain in epitaxial films and determine the amount of relaxation. Also one can determine ...
3
votes
1answer
50 views

Forces of suction in WIllie Wonka's Chocolate Factory (filmed 2005 starring Johnny Depp) [closed]

Before I begin the question: I am in no way judging this movie, just happened to be casually watching it and saw the scene (referred to below) and thought to post this question. The scene: Boy falls ...
0
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0answers
20 views

Mechanism of failure for sudden application of force with no supports?

Just as an example to my question here, suppose one goes clay pigeon shooting. The bullets fracture the clay pigeons and I'm curious as to how this (or any other fracture where there is sudden loading ...
0
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1answer
27 views

Does hardening reduce the ductility of a metal?

Is hardening equivalent with reducing the ductility of a metal and improving the yield strength of it?
0
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0answers
27 views

How to achieve transmission only at normal incidence?

Is there any material that only transmits normally incident radiation and reflects it when it's incident at any other angle? Or any way to achieve such an effect? For example, a mirror that if you ...
0
votes
1answer
36 views

Is strain always relative to some initial state?

Let us say I am given a material with no knowledge about its history. Can I somehow calculate its strain ? Or a strain is always relative to some initial state (change in length/initial length) ?
0
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0answers
28 views

How to simulate “inside-out” geometries of a structure?

How can I simulate the structural deformation of a physical material to find all possible "stable" inside out forms? For example, some dome shaped rubber caps can be pushed inside out, like the ...
3
votes
0answers
38 views

How “steady” are screw threads?

I have a setup whereby two stainless steel end caps screw into a similar tube about 100mm in length and 25mm internal diameter. Thread is fairly standard, and is finger tight. The question is: ...
0
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0answers
20 views

Why Pt is used as counter electrodes in Dye sensitized solar cells

Why Pt is used as counter electrodes in Dye sensitized solar cells.What are the properties of Pt to be a electrode material. ...
6
votes
2answers
91 views

Why does glue stretch straighter than string?

So I have some bottles of lemonade and I peeled the labels off both of them, revealing the glue underneath. When these bottles were next to each other the glue stuck. I pulled them apart and it forms ...
2
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1answer
47 views

How is spring steel so hard?

The mechanical properties of a steel object are influenced by the metal composition, the manufacturing process, and the final heat treatment of the object. Spring steel is a steel that was heat ...
0
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0answers
27 views

What does temperature coefficient of resistance depend on?

I tried looking up on Google if there was an expression for the temperature coefficient of resistance(TCR) of a material in terms of other fundamental factors, but couldn't find any. Specifically I am ...
0
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0answers
17 views

What are the physical optical limitations photonic metamaterials can offer?

Modern technology has introduced new photonic metamaterials that can extend optical properties beyond what standard materials can offer. For example a negative index of refraction is now possible ...
1
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0answers
28 views

Internal heating effects of a circuit element?

The heat-up of a solid circuit component in an electric circuit (for which no chemical reactions, phase changes reactions or other stuctural changes take place) may include: Joule heating $\dot ...
2
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0answers
14 views

What physical parameters are really being described when a rope manufacturer cites “elongation %”?

I have a precision pulley system sensitive to micron displacements. I am having issues because I need a cord with low tensioning force, but also low stretch. I am getting some weird hysteresis in the ...
-3
votes
1answer
55 views

Overloading stresses wooden planks beyond their elastic range, causing them to fail? [closed]

info: In a video on youtube in an unsafe way a car is boarding a ship going over two wooden planks. It looks to me that there two 2x10" wooden boards support a 5,000 lbs car/truck (a not so light ...
1
vote
2answers
66 views

When doping a material, why is As called impurity?

Doping is the act of adding impurities to Group-IV elements to e.g. improve their conductivity. Though it is improving the conductivity, why is it called impurities?
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0answers
8 views

Transformation Diagrams for Ceramics

So, in the field of metallurgy, there are a few varieties of phase diagram that are used to predict the post-processing characteristics of alloys. These include Time-Temperature Transformation ...
0
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0answers
16 views

How can I tell apart the composition of my soft ferrites

I have an assorted bunch of soft ferrites. I need to know which ones are MnZn and which ones are NiZn, so I can sort them for usage at different frequencies.
1
vote
1answer
25 views

To describe crystallity structures of this ferromagnetic material

MOKE microscope picture of the ferromagnetic Material $Co_{40} Fe_{40} B_{20}$ of 20 nm thin film All other pictures look the same, also from different angles: [0,360] by 15 degree separation. I ...
2
votes
0answers
32 views

Effects of cutting carbon nanotube buckypaper

Carbon nanotube buckypaper is a film/paper made from a mesh of carbon nanotube fibers, where each fiber is a bundle of a couple hundred nanotubes. This paper is flexible and tough like normal paper, ...
3
votes
3answers
103 views

How does radiation degrade mechanical parts and electronic devices?

I'm running out of places to look (lots of Googling, SE, [articles and books are too specific and never give a good overview]), and yet I am still unsure about how exactly radiation can degrade ...
0
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0answers
28 views

Magneto Optical Kerr Effects

I have a few questions on MOKE setup. Firstly, why is calibration of the coils necessary? Is it to get a relationship between the voltage and the Magnetic field? Secondly, why do we have to normalise ...
2
votes
0answers
23 views

What is the volume magnetization of Fe3O4 (magnetite) monodomains at room temperature?

Magnetite is great stuff for making ferrofluids and has a huge amount of literature. Yet I can't seem to find an answer to the simple question in the title. The magnetization of various bulk ...
0
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0answers
29 views

Why do some materials have a negative coefficient of thermal expansion in all directions?

Those materials are especially ceramic-glasses. I've found some studies about how does it happens in one dimension (for example a nanocrystalline has a silica helix that works like twisting spring, ...
5
votes
1answer
81 views

Why does aluminium-on-glass mirror work without distortion?

I have read an article about glass (zerodur) with low thermal expansion coefficient. It is mentioned that large casts of such glass are covered with reflective layer of Aluminium and used as mirrors ...
3
votes
2answers
35 views

Air bubbles in Ice and cause for their shape?

I was looking at the ice formed in my refrigerator and found out there were a lot of air bubbles inside it. The shape of the air pockets seemed strange to me. There were many small spherical ones ...
0
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2answers
16 views

How can you see the difference between a melamine plate and a plate with a melamine coating?

How can you see the difference between a melamine plate and a plate with a melamine coating?
0
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0answers
20 views

Spring limitation

Is there any limitation in acceleration and frequency of a spring. Please, imagine a horizontal spring with an object of mass $m$ attached in the free side and the friction is neglected. ...
2
votes
1answer
40 views

Why does sunlight cause colors to fade?

If you leave something outside, its colors seem to inevitably fade or bleach due to exposure. Is this due to UV absorption? What sort of mechanism causes this - is it that man-made dyes deform on a ...
0
votes
2answers
80 views

Does metal sublimate?

I know that solid water (ice) sublimes ("evaporates" straight from solid to dissolved gas) in air. On the other hand, some metal objects seem to last forever (e.g. gold, stainless steel and other ...
0
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0answers
17 views

Reflectance spectrum and Real Refractive Index Relation

I have taken in the laboratory mesurment of the Reflectance spectrum of a material and via mathematica calculated the phase for Kramers-Kronig Relations,and finnaly i calculated from it the real part ...
0
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1answer
27 views

Mechanical properties and nanocoatings

How do you model the changes in the mechanical properties of materials coated in with nano-materials? If I coat abs plastic with amorphous diamond how does that change the sheer, tensile and other ...
0
votes
1answer
339 views

Ohmic and non-ohmic conductors

What sort of materials are ohmic and what sort of materials are non-ohmic? I have tried looking around on the internet and have not found any clear way to differentiate between ohmic and non-ohmic ...
0
votes
1answer
33 views

Why does adding thorium to a TIG welding electrode improve the arc?

Why does adding thorium to a TIG welding electrode improve the arc? What are the physics behind this and other tungsten alloys used for improving TIG electrodes?
1
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0answers
47 views

How does force transmit through a solid block?

If you take a solid block, say, a cube of side length $l$ with density $\rho$, you place it upon a solid floor, and you apply an external pressure of $p(x,y)$ on the upper face ($x$ and $y$ define a ...
4
votes
2answers
60 views

First-principles derivation of cutting force

I know that the amount of force required to separate a material from itself is linked to the surface energy of that material. However, looking at just the surface energy laughably underestimates the ...
12
votes
3answers
478 views

What are the rules for breaking a glass with your voice?

So, this morning I woke up and remembered something I discussed about with one of my friends: Can human voice really break a wine glass? So I looked it up and after checking many websites and ...
1
vote
1answer
25 views

What is the physical process behind wool shrinking when dried?

Wool is a fibrous material, but other fibrous materials do not suffer the same problem. Let us set the scene; a woollen jumper shrinking when put in the washing machine, then the dryer. This involves ...
4
votes
1answer
52 views

Why does the refractive index not mirror the Lorentzian peak shape of the absorption index?

In the characterization of materials, there are many methods used: One of them is infrared spectroscopy. In a lab we saw the indices of refraction and absorption of a certain (semiconductor) solid ...
0
votes
1answer
89 views

Tension and compression in bicycle wheel spokes - what holds the wheel in place?

I assume that most of the weight of the bicycle is taken by spokes in tension, but there must also be a contribution from spokes in compression. Any idea of percentages?
-3
votes
1answer
39 views

how much weight can you put on a bike tire? [closed]

How much weight can you put on a bike tire? What does it depend on?
0
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0answers
17 views

Is there a list of (the solid state version of) electron affinities?

I'm doing some energy band diagram analysis for a few scenarios, and I need the Electron affinity as defined in solid state physics for a few materials. Note that this is different than the one taught ...
1
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0answers
23 views

What will my diamond fibre shirt look like?

So, during an idle moment when I mused that our experimental setup would be a lot less hassle if it was made from a 1kg single crystal of diamond, this thought occurred to me... Since single crystal ...
1
vote
1answer
87 views

Why is elastic modulus greater than shear modulus?

I was looking at data for elastic modulus $E$ and shear modulus $G$, and found that $G$ is always lower than $E$. So I'm wondering what are the underlying principles that may be the cause of this. ...
2
votes
1answer
73 views

A reliable aluminium battery that charges in a minute. What's the catch?

This article Ultra-fast charging aluminum battery offers safe alternative to conventional batteries, phys.org. reports on the finding by a Stanford group of an aluminium-ion battery that can ...
0
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0answers
39 views

Help with a couple of materials science questions

My first post on this forum is asking for some assistance in answering some questions. I was hoping as well as being given an answer, you could offer a little explanation so that I can understand - ...