Bart
  • Member for 4 years, 10 months
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2 answers
1 votes
511 views
Does a washer really increase static friction force?
6 votes

No it doesn't, and it isn't meant for that either. A standard flat washer, that is. It's meant to give the nuts and bolts a better support, and it protects the material against the nut which may ...

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2 answers
2 votes
2k views
Why do petrol engines have lower compression ratio than diesel engine?
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4 votes

It's not because of the fuel, but because of the process. The diesel process differs fundamentally from the otto(petrol/gasoline) cycle. In the otto cycle, where fuel is present in the cylinder ...

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3 answers
2 votes
2k views
Manual transmission: Why downshifting is less smooth than shifting up?
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4 votes

That's because when you upshift, you select a lower ratio, so your clutch speed drops. Since you took your foot of the gas, the engine rpm also dropped, and now the clutch and engine speed are close ...

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5 answers
5 votes
4k views
What colour of tarp will let in the least amount of heat?
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4 votes

As a practical and cost effective solution, I'd advise using aluminium foil, or tin foil as it's also called. Please realise that it's rather fragile, so it's best to glue it to a plastic foil or ...

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1 answers
2 votes
6k views
Specific energy vs Specific power in batteries
4 votes

Batteries can't deliver unlimited current. Internal resistance, and limitations of the chemical reaction within the battery make that it can only deliver so much current. And the more current is drawn,...

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1 answers
3 votes
1k views
Quick release for spring-loaded rod
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4 votes

The force which is needed to pull the pin out, will depend on the friction of the pin and the neighbouring material, and the surface at which the friction works. Let's assume a friction factor $\mu$ ...

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3 answers
1 votes
81 views
Mapping of vehicle to its horn sound
3 votes

Ships have loud horns because they need to be heard from far away. Because they can't stop abruptly. For cars it is less so, for scooters even less. A car's engine isn't powerful enough to drive a ...

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2 answers
0 votes
858 views
How to find the center of gravity(Cg) of machine?
3 votes

You can use the a finite element-like method like you're describing, chop up the object in box shaped pieces and combine their individual weight and gravity centre(the exact middle with boxes), but ...

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4 answers
3 votes
222 views
Rapidly cool a flue gas without water circulation
3 votes

Your approach is not an unusual one, engine brakes to measure horsepower usually make use of such a method, but they use much bigger water barrels. To answer your questions: "Can I just fill a ...

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3 answers
0 votes
2k views
What determines the maximum possible slope of rail transportation (without rack)?
2 votes

The actual maximum attainable slope is determined by the weight of the locomotive, the total weight of the train, the rolling friction of the carriages, and the kinetic(sliding) friction between two ...

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2 answers
2 votes
2k views
Steering wheel torque when car is turning
2 votes

It heavily depends on the caster that the suspension is set at. Caster makes the wheels go back to neutral position. The more caster, the more torque is needed to keep the wheel at a position. Scrub ...

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1 answers
2 votes
124 views
How to Determine Tensile Strength of PMMA Optical Fiber?
2 votes

Basically, materials have a tensile strength, and a yield strength. The latter describes how much it elongates under stress, the former how much stress it can have before breaking. It is always given ...

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1 answers
4 votes
8k views
How to bend copper heat pipes?
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2 votes

Copper is notoriouos for hardening and breaking under bending or hammering it, or working it any other way. To keep it soft and flexible, you have to anneal it often while working on it. It also bends ...

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2 answers
1 votes
6k views
Dc motors: relationship between PWM frequency and Torque
2 votes

Remember: current is proportional to torque. It would be linear like you expect if it was like: PWM pulse high: Instant full current, and thus full torque. PWM pulse low: Instant zero current and ...

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1 answers
0 votes
71 views
What do I call this shaft that drives the rubber stopper into the glass vial in a vial stoppering machine?
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2 votes

A camshaft is rotating a cam that is part of the shaft. It seems the cam acts on a roller, fixed on a push-rod, and so pushes down the push-rod in the guider. I think the push-rod pushes the rubber ...

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2 answers
4 votes
82 views
What are the differences between Gauge and Absolute pressure?
2 votes

It doesn't seem that the test creator relies on your ability to differentiate between absolute and relative (or gauge) pressure. It's not mentioned anywhere, other than in B where he wants you to give ...

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3 answers
1 votes
899 views
How can I build a micrometer diameter laser beam from a common laser diode?
2 votes

If you have one convex and one concave lens, you can effectively make the laser beam smaller and more concentrated while still having a parallel ray. I believe it's called a galilean lens. It would ...

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2 answers
5 votes
161 views
How to calculate the pressure loading of a vented silo explosion?
2 votes

The pressure in the silo is determined by the temperature rise, caused by the combustion. The end temperature after combustion can be calculated like this: $$T_{end}= \dfrac{E}{(m_{air}+m_{fuel})C_V}+...

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1 answers
0 votes
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Connecting power lines around corners
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2 votes

You can easily see that the wires don't allign(parallel) with the dotted line which would be the line they should follow to maintain the same mutual distance. To calculate the widht the mast should ...

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2 answers
2 votes
2k views
Required torque to move 6000kg at 27.77m/s
2 votes

To overcome hill resistance, you need 2977 Nm or 2195 ft*lbs of torque at the wheels. Assumed that the gravitional acceleration in your situation is $9.81m/s^2$, as it approximtely is everywhere on ...

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1 answers
2 votes
135 views
Cruise Control Project on Toy Car
1 votes

SimuLink is a great environment for learning about and developing a cruise control system, since it provides real life/time testing while observing every element in the system. The resistances of the ...

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2 answers
0 votes
48 views
Theoretical maximum generated power for a given torque
1 votes

You're supplying a power of only 30 microwatt, so in a day 2.6 joules will be generated. That's very little. 1 oz-in is about 0.0071 newton meter, 100rpm is about 10.5 rad/s. 0.0071Nm at 10.5rad/s ...

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2 answers
3 votes
91 views
Battery Swapping in Electric Cars
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1 votes

This idea has been suggested often, but there's way more to it than you'd think. One big problem is that batteries are heavy, and there are multiple problems arising because of this. The main thing ...

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3 answers
-2 votes
146 views
Inlet of an ICE
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1 votes

Air impurities are no issue for an ICE, only dust and other bigger particle matter are. The material of a surgical mask has little flow capacity, so a bigger filter is needed than normal, without good ...

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1 answers
2 votes
772 views
Can lamda sensor 4.9 be used without the special LSU-IC?
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1 votes

No you can't. The LSU4.9 is a wideband sensor, and so differs from the old school narrow-band zirconia sensors that just produced a voltage. The wideband incorporate an oxygen pump along with a ...

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2 answers
1 votes
62 views
Cylinder Reconditioning
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1 votes

It depends on the application. I think it's better described as play. Tolerance says something about the requirements regarding precision of the production, play says something about the space between ...

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3 answers
3 votes
2k views
Preheating Diesel before injection?
1 votes

Everything that gets the mixture in the cylinder hotter makes for a more efficient combustion. That is because the power of the engine depends purely on the pressure exerted on the piston, and the ...

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2 answers
3 votes
5k views
Friction clutch and the force required
Accepted answer
1 votes

To answer your questions: Yes, a lot of heat gets produced. Most of it will sink into the flywheel, but the clutch does get very hot. That's why it's good to keep the revs low when feathering the ...

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3 answers
1 votes
104 views
heavy duty cargo bike - which direction to choose
1 votes

You shouldn't put the load on the front, above the front wheel(s). That's the worst possible location for multiple reasons. It'll get you smacked on the road: 200kg located above the front wheel sure ...

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2 answers
3 votes
125 views
Is it Possible to Generate Power From Sewage Sludge?
1 votes

In order to make use of it as a fuel, you could consider these options: - Processing the stuff with micro-organisms like bacteria that can create methane from it, or other usable fuels. - Drying it ...

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