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1500 questions
13
votes
3 answers
Measuring longer distances with high accuracy
I am involved right now in the fabrication of steel structures on the order of 5-50 feet long. Presently, we measure these structures with garden variety commercial tape measures. Most of the time, we work to a tolerance of about +/-1/16" and don't…
Ethan48
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13
votes
4 answers
How can I tell if I got counterfeit aluminum?
I recently received an order of extruded aluminum strip 3/32" thick that supposed to be 6061 hardened to specification ASTM B221. However, when we tried to bend it, it broke and the interior looked like cast zinc coated with aluminum. Is 6061…
Wallace Park
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13
votes
1 answer
How does a (pulley based) continuous variable transmission (CVT) work?
How does the (pulley based) CVT achieve the following?
no requirement for a clutch
fuel economy
smooth gear transition
NMech
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13
votes
2 answers
How do the bubble oscillations in two-phase flows affect the dissipation rate of turbulent kinetic energy?
I am investigating the effects of bubble oscillations (calculated using the Rayleigh-Plesset equation for bubble dynamics) on the turbulence in two-phase flows. Since I am using cryogenic fluids, the thermal effects also play a role. I am trying to…
Karthik Venkatesh
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13
votes
2 answers
Do "analog FPGAs" exist?
I am thinking on analog circuits, whose circuit design could be read (or, at least, significantly altered) from software. Do they already exist?
peterh
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13
votes
2 answers
How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?
For an embedded Linux system, if I have two or more network interfaces, how do I ensure that they always get the same interface names every boot
In other words, I want, for example, eth0 to always map to one physical Ethernet port, eth1 to the next,…
Patrick
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13
votes
4 answers
How much clearance does a car need when turning a corner?
I am contemplating buying a new car. However, the approach to the underground garage in my apartment has a 90 degree frustrating turn. Given the dimensions of the approach and car, what is the max turn circle for the car to fit the garage and…
Misha
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13
votes
8 answers
Is there a reason (in terms of the physics involved) why it is better to push start a car in 2nd gear rather than 1st?
I am struggling to understand why it is recommended to push start a car in 2nd gear rather than 1st - in terms of the physics involved, I fail to see a reason why this would be the case. I have compiled where I am at currently with a for/against…
PhysicsGuy123
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13
votes
6 answers
Distance sensors with accuracy of 1 mm?
I am making a device for measurements. I would like to measure the distance within accuracy of 1 mm. Range could be 2 cm to 15 cm . I looked at Proximity Sensors but the readings displayed by these sensors are not steady.
I wish to measure the…
JustCurious
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13
votes
4 answers
Easy nonlinear model for large deformation of a beam
I have a beam subject to twisting and/or bending forces as well as linear compression force along its main axis. It is modelled as an isotropic beam, but if anisotropic is not too far off then that's okay too. The beam is capable of large…
imacube
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13
votes
8 answers
Why is air pressure in all directions?
Here is a typical definition of air pressure:
Air pressure is caused by the weight of the air molecules above. Even tiny air molecules have some weight, and the huge numbers of air molecules that make up the layers of our atmosphere collectively…
oyvey
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13
votes
3 answers
How different are dc motor designs from dc generator designs?
Some dc motors can be used as generators as well by applying mechanical torque to the output shaft to induce a current. However, even if a dc motor can do this, I imagine they were not designed for this purpose and thus perform less efficiently…
Paul
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13
votes
5 answers
How is a mechanical system designed and tested without building a physical model?
I am new to mechanical engineering, although I have a scientific background (postgrad in Mathematics), and I (mostly) code for a living.
I have an idea about creating a mechanical device; I envisage it will entail gears, linkages and actuators.
I…
Homunculus Reticulli
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13
votes
5 answers
How to calculate lever force when lever has uniformed distributed load?
We have a simple class 1 lever:
$$\begin {array}{c}
\text {5,000 kg} \\
\downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \,…
Van
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13
votes
3 answers
How to prevent deposition of dust on ceiling fan blades
It is well known that dust gets deposited on a rotating ceiling fan because formation of a boundary layer over fan blades. The air layer next to blade surface is stagnant due to no-slip condition and the presence of a strong viscous force.
How could…
Debanshu Thakur
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