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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2answers
62 views
Equation describing magnetic hysteresis
So when you're looking at B-H curves for ferromagnetic substances, you often see these magnetic hysteresis curves, which occur, I gather, largely because of domain formation which has some reversible ...
3
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1answer
124 views
(Botanical) branch bending under gravity
I'm a PhD student in maths, and attended my last physics class some 15 years ago, so you can imagine my competences in the field.
My supervisor (also not a mechanist) cant tell me how to proceed ...
3
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1answer
97 views
What ring weave disposition should be the most resistant against stabbing and/or how to determine it
In a website that I am studying so I can build a Chain Mail, I have found a page featuring a lot of different Ring Weaves to build them.
I want to determine which one is the best to provide ...
2
votes
1answer
42 views
Is this 2D structure triclinic?
The only rotation axis obvious to me is rotation by 360 degrees, the identity. Vertical mirror planes I've been dicing and cutting it through several planes and I still see none. Yet, the structure ...
1
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1answer
82 views
Semiconductor problem: how much Boron is required to establish a certain amount of charge carrier density
The problem description is as follows:
Boron is used to dope 1 kg of germanium (Ge). How much boron (B) is required to establish a charge carrier density of 3.091 x 10^17 / cm^3. One mole of ...
1
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1answer
84 views
Why can we analyse force balance on a dislocation?
Dislocation (like screw or edge dislocation) is not a 'real' thing, while Newton's laws only apply to a real object (no matter macroscopic, like stars, or microscopic, like atoms).
In the derivation ...
1
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1answer
392 views
Properties to select suitable materials for making permanent magnets
I have read that soft iron is suitable for making a permanent magnet. Because it is required for permanent magnet to have high coercivity and high retentivity.
Same text also said earlier that soft ...
0
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1answer
148 views
Acoustic Metamaterials: Negative Bulk Modulus?
In acoustic metamaterials we have simultaneously negative bulk modulus, $\beta$, and effective mass density, $\rho$.
I understand how one can obtain a -ve $\rho$ by constructing a solid-solid system ...
4
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0answers
41 views
Order of magnetic phase transitions
Is there any phase transition occur in paramagnetism to diamagnetism transitions state. What should be the order and how will I calculate the order?
4
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0answers
94 views
Why does the overhand knot jam but the figure-8 knot doesn't?
After tensioning a rope with an overhand knot in it, it is often very hard if not impossible to untie it; a figure-8 knot, on the other hand, still releases easily.
Why is that so? Most "knot and ...
4
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0answers
776 views
Inflating a balloon (expansion resistance)
I am doing a quick calculation on how to calculate the pressure needed to inflate a perfectly spherical balloon to a certain volume, however I have difficulties with the fact that the balloon (rubber) ...
2
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0answers
54 views
How can I determine the type of magnet used in a DC motor?
I repair electrical motors in a workshop and sometimes I must repair permanent magnet DC motors and other motors that use permanent magnets. I need to specify type of permanent magnet (Ferrite or ...
2
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0answers
706 views
What is the cause of strain hardening and strain softening?
Why is it, that - if displayed in a strain/stress-diagram - the curve will at first be linear, and then change into a "curved shape", where it will first decrease again, and only later increase again? ...
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0answers
50 views
Is it possible to increase refractive index at lower densities?
Are there any materials for which the refractive index decreases with density? It seems that for most materials we would expect there to be a positive correlation between density and refractive index, ...
1
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0answers
48 views
Where can I find a complete list of metamaterials up to today?
Where might I find a list of all the metamaterials up-to-date?
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0answers
31 views
AWG chart for Tungsten
This is the American Wire Gauge (AWG) chart page for Copper that I found from Google:
http://en.wikipedia.org/wiki/American_wire_gauge
Is there a similar table for Tungsten/Wolfram available?
Has ...
1
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0answers
44 views
Is it right to cut a slot on some material before bending?
I made a suggestion to my boss to cut a thin, shallow slot on a metal sheet on the side we wanna make 90°, so that the machine could bend it. However, the outcome was "The metal broke".
My boss was ...
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0answers
124 views
Electrical machines: electrical and mechanical properties of steels and cast iron
I would like to know a good source of information for the common metals (steels and cast iron). Information that I need are basically the mass density and the electrical conductivity or resistivity. ...
0
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0answers
7 views
$SiO_2$ PVD deposition to HDPE (plastic)
Is it possible to deposit $SiO_2$ onto HDPE plastic parts (Fresnal Lens)? Will the deposition
disrupt infra transmission?
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0answers
19 views
UV light penetration into silicon
I'm in need of some information about UV (particularly UVA) light's ability to penetrate into silicon. Specifically, I am looking for a relationship between wavelength and penetration depth. Also, if ...
0
votes
0answers
35 views
Material physical properties of a desk related to vibration propagation?
I'm a software programmer (not a physics expert) trying out a smartphone vibration detection algorithm on desks, and I want to measure the impact of the desk's material features on the algorithm. Are ...
0
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0answers
15 views
Is resilience a measure of power expended upon unloading?
I read the definition of 'elasticity' and 'resilience on Wikipedia:
Elasticity is a property of materials which return to their original
shape after they are deformed.
Resilience is the ...
0
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0answers
80 views
Whats the contact area for elastic contact between a cylinder and a plane surface?
I am trying to determine the contact area between a cylinder and a plane surface of two different materials so that the plane lies tangent to the cylinder. There is elastic contact between the two ...
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0answers
31 views
Does graphene actually remain strong for macroworld engineering?
I heard that people envision strong structural materials made out of graphene, but I heard it may weaken when being stack in layers. Is graphene viable for macroworld structural engineering or is it ...
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0answers
111 views
Phase diagram problem for ternary system
For a ternary system, three composites are present.
Temperature is also a variable.
Assuming that pressure is held constant, what is the minimum number of phases that may be present in a ternary ...
0
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0answers
77 views
Which viscoelastic material that transparent for Infrared light?
I have to work with viscoelastic materials, since I tried to use a silicone polymer (silly putty) which expect to IR transparent properties, however, IR camera shown the black color (means their ...
