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1500 questions
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2 answers

Does having 2 engines together increase anything?

If I have a vehicle (V1) with one 100 kW engine and an identical vehicle (V2) with 2 of these 100 kW engines, will this mean that V2 will have double the torque of V1 and double the top speed of V1? Suspected Answer It's not like in a series…
3kstc
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Three-phase versus single-phase operation of a generator

My generator (a Fermont MEP-803A, 4 cyl diesel, 10kW rated) can run in three distinct modes: Single-phase 120V, in which one terminal is hot, and another is neutral Single-phase 120V/240V, in which two terminals are hot, and another is neutral. The…
Diogenes Creosote
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Is a single large impact better than several small impacts for breaking ice

I'm designing a device that uses impact to remove ice from sidewalks. I have a question about how to best design the impact mechanism. I can design it to deliver several light impacts or fewer harder impacts. The energy will be the same in both…
henradrie
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3 answers

Are there materials that are good at transmitting sound but thermally insulating?

I'm wondering if there are materials good at transmitting sound but is thermally insulating? I'm trying to figure out a good material in an engine exhaust application which will pose a barrier to the high-temp exhaust flow, but allow the exhaust…
Poompil
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What does 'easily reversed' mean in the NIST spectral database?

I'm trying to do some processing of optical emission spectra from sputtering plasmas, and am confused by what NIST means by 'easily reversed' in their notation. Anyone have a clue?
wordsforthewise
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Can I seal the inside of a water well to use it as water reservoir when the well is dry?

We've had unusually dry weather and our well has run so low that we had to call in a water hauling company to refill it a few days ago. The water man told me that even though he dumped in ~ 1000 gallons, a great part of it will seep out of the well…
cannotcompute
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3 answers

P&ID Symbol identification, unknown meaning

I'm aware that answers may vary and it really does depend on the company/country where the PID was drawn but I have checked back for the last 30 years and found no drawing legend that describes what this symbol is and was hoping someone could point…
SimpleJack
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2 answers

How to size a heat exchanger for a shear thinning fluid?

To size a heat exchanger, I need to know (among other things) the Reynolds number (Re) as an indication of the flow conditions. The Re number depends on the viscosity. In a shear thinning fluid, I can't assume a constant viscosity, instead it will…
mart
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What are typical forging loads?

What are typical forging loads for various metals and configurations? I know that the typical test for a metal is to upset a 0.750" high x 0.500" diameter cylinder to a height of 0.5", but could not find any actual tables of what kind of load it…
Wallace Park
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What are the engineering challenges in WIG craft development?

Wind In Ground (WIG), is an old concept. In short: Wing-tip vortices create an additional drag on the aircraft known as the induced drag. However, when the flying craft (or bird) flies close to the ground or water, these vortices don't get enough…
Subodh
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How Much Efficiency is Lost in a Gear Train

I want to get a rough estimate for the transmission efficiency of two different gear trains. One is a one-stage gear train with 11.67:1 ratio (140/12 teeth) and the other is a compound two-stage gear train with overall gear ratio of 18:1 (72/12 +…
Inf_E
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Going distant in sourcing machining

My North American facility is looking at a major shut down this fall. In the area, three other large facilities are also doing either shutdowns or expansions in the fall. A last minute project that I have been assigned requires a couple of weeks…
Myles
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What machinery should I invest in for tapping and threading?

I've found myself tapping and threading a lot lately, and doing so with hand taps and dies. What would be the next step up from using a drill-press to cut holes for tapping, and a lathe for turning parts to diameter for threading? What are options…
feetwet
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6
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Why do we prefer resistance over conductivity in describing Ohm's law?

In my mechanical engineering training , I've noticed that many constitutive relations (e.g. fourier law, poiseuille law, hooke's law) involve a flux which increases as the material parameter increases. In heat transfer and fluid flow, this is…
Paul
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Removing water and nitrogen from reactor effluent

I wish to remove water and nitrogen from my reactor effluent in order to decrease downstream equipment sizes and subsequently capital costs. Stream composition: ${H_2S}$.................5.6% ${SO_2}$.................3.3% ${S_2}$.................9.2%…
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