# Tag Info

0

you could have a larger amount of the softer material so by the end of the cutting you have zero soft material left.

2

It depends on your definition of "cutting". Hardness of a material relates to its yield strength - the stress it can sustain without plastic deformation. Push a "soft" material with a sharpened point into a "harder" material, and the tip will go blunt because the soft material deforms. This is why diamond powder is often used to coat grinding wheels etc - ...

3

Firstly, I suspect that oxidation will throw a spanner into any such plan. For metals like aluminum, which have a very high affinity for oxygen, a "virgin" surface will begin to tarnish almost immediately. The second problem is that metals have microstructure. Neighboring crystals in a polycrystalline aggregate such as a metal piece have to satisfy certain ...

6

One can cut a any material by using a (slightly) softer abrasive material and a soft tool that can press the abrasive against the cutting surface. The tool will simply abrade much faster than the object that is being cut and it will take lots of abrasive and time, but that's OK. This kind of abrasive cutting/grinding is quite common.

4

The light rays are crisscrossing in front of you now! $_1$ Do you consider it as soft? It depends on your definition. Your softy light is used to cut hardest materials by using the process called laser cutting. The focused laser beam directed at the material, which then either melts, burns, vaporizes away, or is blown away by a jet of gas.$_2$ ...

1

I believe that it depends on the method of cutting, and on the energy of the material used for cutting. Sure, air can cut steel. If it is heated to several thousand degrees in an arc welder. However, air at the same temperature as the steel is not likely to cut the steel. I believe the method you are asking about is the classic material removal method. ...

1

I believe a fast-rotating blade can cut a harder material.

5

Yes, is possible. For example, you can see this, water can cut steel.

1

There's a nitinol wire that stiffens when warm and softens when cool. It's been used in various patented heat engine applications. see this reference http://www.imagesco.com/articles/nitinol/09.html

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There are materials called desiccants which absorb water. And an open cup of liquid water can sometimes serve as a convenient source of humidity. But if you are trying to regulate the activity of water in a system to a particular level, then you may have to introduce additional phases into your system. You'll have to design a system which gives you the ...

3

Let's take a look at what forces a concrete beam or column can be expected to handle: Compression, from weight being applied directly on it. Bending, from any bending moments. Concrete can handle being compressed very well, since it's basically sand and gravel. It can stand compressive loads of 3000 - 6000 psi, which is huge. However, it doesn't do so ...

3

Concrete is very strong in compression but weak in extension, so it isn't good at supporting stretching or bending forces. By contrast steel is able to cope well with stretching and bending forces. So by combining the two you have a composite structure that resists compression as well as concrete and resists stretching and bending as well as steel. In many ...

2

When you want to make a solenoid core, you are typically interested in a material which exhibits low eddy current losses (eddy currents are induced during a change in field, and they result in heating / losses in the core - this is almost never desirable except in the case of induction heating), and with high permeability - the latter enhances the magnetic ...

0

The answer therefore is a qualified No. A current passing through a material will create a field, which will certainly affect the magnetic permeability $\mu$ if the material is magnetically nonlinear. If the material is mu-metal then it will saturate at a low field. So if you had a rod of mu-metal for example, you know the permeability μ but does that ...

0

Absolutely. Saturation of the magnetic material by DC currents/magnetic fields is a primary concern in power electronics, where it can be one of the primary failure mechanisms, if the designer underestimates the significant drop in permeability, which leads to a drop in inductance. Usually the DC magnetic field is not caused by current trough the magnetic ...

5

Thumbs up for a interesting and curious question. Yes there is worn out due to friction for sure when two surfaces rub along with each other, like you said worn out keyboards are a good example of it. Also, hardness does play an important role in it. Hardness is a physical property and there are different measurements of hardness: scratch hardness, ...

118

For organic matter, such as bread and human skin, cutting is a straightforward process because cells/tissues/proteins/etc can be broken apart with relatively little energy. This is because organic matter is much more flexible and the molecules bind through weak intermolecular interactions such as hydrogen bonding and van der Waals forces. For inorganic ...

12

It depends on what's being cut. When metal is cut, what happens is that, on a small or not so small scale, it shears. That means layers slide over each other. The mechanism by which they slide over each other is that there are imperfections in the crystal structure called dislocations, and the crystal layers can move by making the dislocations move in the ...

2

Ferromagnetic materials contain magnetic domains within which the electrons spins are aligned to give a net magnetic moment. Bulk magnetisation is done by changing the alignment within the domains so they all align in the same direction and their magnetic fields all reinforce. Anything that puts energy into the crystal lattice can randomise the alignments ...

1

Fundamentally, yes. One needs to break the time-reversal symmetry by either introducing a magnetic effect or modulating the "glass-like" materials dynamically. Practically, this is a very active research area. One could, for example, inject carriers into silicon dioxide at a very high frequency to achieve the one-way effect.

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