This is a response to a question in Scientific American given by Dr. Quentin Williams who specializes in the deep interior. I searched "Why is the earth's core so hot" on Duckduckgo. (I'm not sure if current posting guidelines allows me to give links to periodicals?)
There is a great article by Tom Irvine on why the units are unusual. I have myself wondered this for some time, working in this field. The units are generally motivated by the practical considerations of signal processing, viz., getting a meaningful measure of amplitude that is free from the...
I've been wondering about this question for some time now. There are the following two contributors:
1. Heat left over from the planet's initial formation. In the early 19th century Lord Kelvin estimated the temperature based on a homogenous sphere of uniform initial temperature...
This is really a question of two related parameters:
1. How heavy is the average person?
2. What is the average coefficient of static friction (for all combination of surfaces), i.e., what is 'typical'?
When you answer these two, you should be able to extract an answer.
Remember how to do calculus, matrices, and all that. Math is an indispensable tool, but HowlerMonkey also underscores an equally important point: we need to be able to communicate effectively, succinctly, and with proper grammar and spelling.
There are quite a few other corrosion-resistant materials out there, some of them non-ferrous. Even within the family of austenitic steels you can consider 304L or 316L in the 1/2-hard 3/4-hard or full hard or extruded Cond. F grades as alternatives.
I can also see where Chris is going... those...
What are the static and dynamic friction values for dry and wet soap? I can't find these things anywhere on the net, except for an assumption of the kinetic value of 0.06.
If someone has access to an extensive data sheet on frictional values, then that would help greatly. Thanx
How effective is using steel powder in a polymer/ceramic composite matrix?
I am wondering this from observing this product called Faststeel which is one of those epoxy putty sticks that claims to be steel-reinforced.
I actually think that it will make a material stronger than the matrix...
Kevlar and basalt fiber are two contenders on the practical scale; carbon nanotubes are the strongest on the laboratory/R&D world.
But while there are many fibers that exist with high tensile strength, I still think man has not found any composite, polymer, ceramic, or metal that can come...
I would aluminum alloy is your best bet if you're making a robot. Normally its pneumatic operations and small motors that power it would want less burden on the weight. But it depends.
If you want strength per volume, steel.
Simply put, if you have to handle cyclic loads on small parts...
Great links, but I'm still puzzled as to why MgO isn't as used as often as alumina or zirconia in high-tech refractories.
Currently most engineering is focused on ceramic coatings on a metal substrate. Is this due to the high cost of the ceramic? If I remember correctly there is a lot of...
Zirconia has a very high melting point, about 2700C. This is the primary reason why it is used as a refractory.
However, after some preliminary searches, I found another common ceramic material with a melting point higher than that of zirconia - magnesia (MgO), with a melting temperature of...
I really don't know, and that's a pretty darn good question. I'd like to know myself from some of the experts.
You can probably tell the bond strength roughly by the melting temperature of the solid, which is where interatomic interactions partially break loose. In this case, tungsten is the...
The situation might be more complex than a simple analysis with conservation of momentum.
Imagine two containers in free space connected by a spring.
One consists of viscoelastic tissue like human tissue and the other consists of cold tar, like earth's magma. Which direction would the system...
For argon the answer must be yes. The atmosphere is about 0.7% argon (which is quite a bit if you think about it) by volume, meaning you can distill this gas right out of the air. The cost definitely makes sense here.
Graham's law explains the relation between molar masses on the rate of diffusion. It should be the the inverse square root of the molar masses if I remember correctly, meaning Helium diffuses roughly 3.2 times as fast as argon (turns out that it has around 40 daltons of mass).
However, I need...
I have a question about helium :
If it is the most inert substance, why isn't it used more than krypton or argon for high-temperature incandescent bulbs?
I don't see neon in light bulbs too often either.
Just what, exactly, is its melting point?
I came across a ICSC website saying it decomposes at 350 degrees Celsius. Now how is that supposed to make sense, when it is itself a by-product of wood fires?
It's come upon my interest that besides capacitors, flywheels can also be used to store considerable amounts of energy at impressive levels.
The best material is supposedly carbon fiber, since it can spin at high speeds.
But what about other materials like steel fibers or fiberglass? Those...