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1500 questions
4
votes
3 answers
What are these bent shapes on this elbow in a compressor suction pipe?
See here are the shapes which are made on the suction head of compressor,
What are these, and why are they on the suction head pipe?
Alex Goedert
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4
votes
2 answers
Can a dry-pipe or preaction valve be used to create a branch off a wet pipe sprinkler system?
Individual-head (i.e. not deluge) sprinkler systems come in three flavors:
Wet-pipe systems have water pressure at the head at all times -- they are the quickest to respond, but can't be subject to freezing conditions and are too risky for…
ThreePhaseEel
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4
votes
2 answers
How can I determine how many cycles to average for when taking a measurement using Lock-in Amp if I know sensor spectral noise density?
I am taking a phase sensitive measurement of an AC magnetic field using an SR830 Lock-In Amplifier and a magnetic sensor. I know I have to average over a number of measurement cycles to get an accurate reading. The amount of time I should average is…
phujeb
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4
votes
1 answer
What is a slotted open ring with a thread called (like on bicycle brake levers)?
I'm looking for a small ring that allows a thin cable to pass through but can also lock to close that opening, like on bicycle brake lever screws (shown below). However, I'm having trouble finding the part because I don't know what it's called.
Do…
q335r49
- 141
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4
votes
2 answers
Most efficient way to build a toothpick bridge
In my stem class we are going to have a competition where we have to build a toothpick bridge that can support as must weight as possible, while using only toothpicks and glue. These are the rules:
Each toothpick costs \$10,000.
Each end of a…
Addison
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4
votes
2 answers
What is the advantage of using GPIO pins as sinks instead of sources?
I'm following this tutorial on how to control Raspberry Pi GPIO pins with Python scripts. Instead of connecting the test circuit (LED + resistor) between the ground and the GPIO pin however, they connect it between the +3v pin and GPIO (see section…
Carlton
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4
votes
2 answers
How does a graph with tensile stress-strain curve and compressive stress-strain curve superimposed look like involving true stress and true strain?
If you have a graph with a tensile stress-strain curve of a typical metal or alloy and you superimpose a compressive stress-strain curve on it (from same metal or alloy), how would this look like if you had to sketch it?
I know that when you talking…
strateeg32
- 517
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4
votes
2 answers
Finding the sampling period to avoid loss of signal
We have:
$$ s(t) = 4u(t)−u(t−1)−2u(t−2)−2u(t−3.5)+2u(t−4) $$
where $u$ is the Heaviside function.
I had to draw the graph and find the minimum sampling period so we wont have loss of signal. I have drawn the graph.
$t=kT$
where $T$ is the sampling…
sdfdsffsdf
- 41
- 1
4
votes
2 answers
comparing backlash of different mechanisms
I have a cylinder with a shaft in its center that I need to rotate at 120 RPM on 180°, for costing reasons, I would like, if possible, to reuse the same DC motor that I already use for another system. That motor has a speed of 6000 RPM so I need a…
LiohAu
- 201
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4
votes
1 answer
How can I fit a DN16 flange to a DN10 flanged pipe?
One of the valves on my 3 bar line just failed. Without it, our production has ground to a stop and we can't operate until we get a replacement (which we have already ordered). In order to make a deadline, I am trying to find a way to use a…
jmac
- 242
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4
votes
2 answers
Why is strain also normalized to the parameters of engineering strain?
I get that you normalize stress to engineering stress, so that it is independent of the cross sectional area. This means you can calculate (roughly) the stress needed to elongate the specimen to the degree you want. But why normalize the strain…
strateeg32
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4
votes
0 answers
How do I loop through annotations in NX using the NXOpen API in VB?
I'm writing a script to extract all the dimensions from a 2D drawing in NX. In doing so, I have been able to get the dimensions and tolerances on all sheets, along with the zone numbers. This has been fairly easy. However, I'm running into a brick…
stonecharioteer
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4
votes
1 answer
How efficient is the opposed cylinder combustion engine design?
The Opposed cylinder design for gasoline engines is rather uncommon, though several have been made in the past.
The expansion forces in an opposed cylinder engine are balanced. For ever force there must be an equal and opposite force. Thus V shaped…
Dale
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4
votes
0 answers
Could someone explain to me the process described in this quote from G.B. Shaw (fragile load transfer system of some sort)?
The idea, as I understand it, is to transfer fragile material (glass bulbs in this case, I believe) from one moving something to another, or over to a platform. This is taking place in the 1920's, I think. Anyway, here's the quote:
However, I…
Ricky
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4
votes
2 answers
Shear rate of a fluid in a container with a sliding PTFE top plate. Will the liquid move with the plate?
I am trying to work out how a liquid inside a container will be affected by the back and forth sliding of a Teflon coated plate such as the one in the picture.
I know how to work out the shear rate of a fluid between two plates moving at different…
user88720
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