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1500 questions
5
votes
1 answer
What kind of motion information can be extracted from 3-axis accelerometer and 3-axis gyroscope sensor data
I have 3-axis accelerometer and 3-axis gyroscope sensor data coming from my bike trip. Until now I have extracted only basic information like overspeeding, hard acceleration and sudden turns.
What additional motion characteristics can I infer from…
NG_21
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5
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Should the corbel angle always be estimated as 60 degrees in masonry construction, or is there a formula to use instead?
In educational construction material as well as engineering publications, the corbel angle for significant excess loads, and also for substantial openings, in an ordinary brick wall is usually stipulated as being taken as 60 degrees to the…
Stilez
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5
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Physical interpretation of the relative displacement tensor?
I've resolved a relative displacement tensor into a strain tensor and a rotation tensor, where
the strain tensor is:
$$
\varepsilon_{i,j} =\begin{pmatrix} 0.2 & 0 & 0 \\ 0 & 0.8 &0.4\\0&0.4&0.4\end{pmatrix}
$$
and the rotation tensor…
Llewy Thomas
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5
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1 answer
Calculating real or more accurate specific impulse
This may fall a little under chemistry processes but I felt it has enough pertaining to aerospace to put it here. Basically, I'm in the process of attempting to develop a way to derive $I_{sp}$ as pertaining to rocket engines rather than rely on…
ecfedele
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5
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1 answer
Material which can be used for resistive heating and simultaneous temperature measurement
I want to embed a wire inside a plastic and heat it to specific temperatures (80$^\circ$C 100$^\circ$C 130$^\circ$C 180$^\circ$C). I want to find a material that is resistive enough for resistive heating, but also I want the wire's resistivity to…
Nic
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5
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1 answer
What coefficients should I use when modeling non-stationary heating of a steel plate?
I am trying to make a model of non-stationary heating on a plate, where I must use an explicit numerical method to solve the model. I decided the plate will be made of steel (0,5% C) and I found that the thermal diffusivity coefficients $k/\rho c_p$…
cvut
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5
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Are there any precedent designs for a mechanically-delayed pressure release valve?
I need to release pressure of around 50psi, after 3-4 seconds of initiating, from a vessel using a mechanical switch. I had considered a pneumatic solenoid, but I want to forgo the inconvenience of charging the device with electricity in addition to…
SmugDoodleBug
- 153
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5
votes
2 answers
Recoil of hydraulic lift/elevator
I noticed that when a group of people enter in an hydraulic lift/elevator often when the last person steps in the lift/elevator has a small but noticeable recoil: the lift goes down a few mm then it compensates.
This creates a recoil.
It seems…
Luca
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What approaches are there for demolishing a structure and how is an approach chosen?
From my office on the 21st floor of a building in Vancouver, BC two parking garages in the process of being demolished are visible. A third is just out of view a few more blocks away.
One of these structures is being taken down by a team consisting…
cclark
- 153
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5
votes
2 answers
Why does blood pressure cuff size matter?
There are a number of sources that confirm blood pressure cuff size can have a significant impact upon the measured reading. (See 1, 2, 3, 4) The most succinct description I have seen is this:
The error that is introduced by too small a blood…
user16
5
votes
2 answers
Gigapascal pressures in a small package
How small/compact can a pump or other mechanism be, that would allow compressing gas (or liquid) to pressures of excess of 10GPa, continuously?
Throughput may be minuscule, of order of milligrams per hour; even lower is acceptable. Also, for "size…
SF.
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votes
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What amplitude is used for a finite element modal analysis excitation?
In a typical finite elements analysis package, a modal analysis gives the N first natural modes, and it is possible to get the equivalent stress and total deformations for each of these frequencies.
But what amplitude did the solver use to get…
Mister Mystère
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5
votes
2 answers
Identifying category of wind turbine
I recently saw a wind turbine that I'm trying to identify the type or category of.
Basically, the turbine looks like two squirrel cage fans mounted side by side on a fairly tall ~40' pole.
The blades of the turbines rotate along the horizontal…
user16
5
votes
2 answers
How to calculate screw pullout strength?
I am designing a system where a beam is acted on by a horizontal force. I intend to hold the beam in place with a set of screws, although I am uncertain how much force they will be able to withstand.
What method can I use to determine the holding…
Sam Weston
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5
votes
3 answers
How to determine reinforcement design strip widths and locations
When designing reinforced concrete slabs it is common to divide the slab into 'design strips', which are then used to rationalise the reinforcement design along (typically orthogonal) lengths of the slab (also known as the Hilleborg Strip Method).
I…
thomasmichaelwallace
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