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1500 questions
5
votes
1 answer
What are the elastic constants for tetragonal zirconia polycrystal (TZP)?
I have six known elastic constants of TZP. What is the relationship between the known and the unknown constants?
Known constants (GPa):
$c_{11}=327\\ c_{12}=100\\ c_{13}=62\\ c_{33}=264\\ c_{44}=59\\ c_{66}=64$
How can I find the others? Is…
Jimmy
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5
votes
2 answers
Synchronous machine power factor and angle
I have a 8-pole synchronous machine (as a generator), which is rated to produce 1000 kVA. Its synchronous reactance is 0.4 Ohms.
It is connected to a diesel engine with the grid frequency 60 Hz.
The load is resistive type, 500 kW, 480 V.
I need to…
tilenslo
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5
votes
2 answers
Mechanisms for moving dual blackboards
I have to make a dual blackboard like the one here, http://www.ucd.ie/physics/lhcb/contact/blackboard.jpg,
My biggest concern is what sort of mechanisms I should use to allow for smooth and easy movement of the blackboards. The boards need to be…
Noor
5
votes
1 answer
What's the concrete core for in a building?
I'm watching the progress of a new office building being built over the road (essentially a manual timelapse).
The way the building progressed was by the pouring of a concrete core in the centre of the building to the full height (~8 storeys),…
thosphor
- 151
- 3
5
votes
1 answer
How are non-continuous internal threads plastic injection molded?
I'm trying to figure out how the heck some of these plastic bottle caps are injection molded. By having the thread on the inside of a cap, this obviously creates an undercut.
Now I've watched some videos on Youtube on the process, and I can see…
Davbog
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5
votes
1 answer
Logic behind location of shear centre
When we apply a vertical shear force Sy and the structure is symmetric about x axis, then why is it logical to have the position of shear center at the location of intersection of line of action of shear force and x axis?
If we go by basic…
Manish
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5
votes
2 answers
How does a rodless electrical linear actuator work?
I want to pull some weight horizontally and for that i have settled for a linear actuator.
The actuator should pull some weight as it moves back and forth as the gif shows.
There are linear actuators i could find but they are too bulky with heavy…
Gandalf
- 153
- 5
5
votes
1 answer
How to store gas on little pulsejet plane?
I am thinking about building small plane with a pulsejet but the engine would need to be roughly 2 cm in diameter. Is it even possible to fit something to store gas on that sized plane? At least for like 10 seconds of running.
valli3
- 59
- 1
5
votes
1 answer
Quick return mechanism for spring-loaded screw
I am looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position.
Specifically, a screw mechanism pushes a spring with multiple of…
PSz
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5
votes
1 answer
What is the most common control method in Underfloor heating?
I am trying to research the common methods on an underfloor heating system that are available in the market.
I know there are usually,
On/Off control to control the flow of water into the pipe
Outdoor reset control to control the supply water…
Tanay Rastogi
- 73
- 3
5
votes
0 answers
What diameter of particles will result in a blocked borehole?
My mine is looking to install a 600 mm open borehole to drop particles up to 150 mm through. It's a 320m shaft to drop ballast down to save time compared to using the drift.
When it gets blocked they typically take a water truck out and that…
Scott
- 51
- 2
5
votes
1 answer
Mathematical expression for power loss in a dielectric
I am trying to prove the equation
$$
\frac{\bar{P}}{V}=\frac{1}{2}E_0^2\sigma_{AC}
$$
which can be rewritten as
$$
\begin{align}
\frac{\bar{P}}{V} &= \frac{1}{2}E_0^2\sigma_{AC}\\
&=\frac{1}{2}E_0^2\ \omega\ \epsilon_0\ \epsilon^{''}_r\\
…
Quaker
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5
votes
0 answers
How to account for pistons inside a free body diagram?
If you have taken basic statics classes you'll remember the free body diagrams used to calculate the forces inside a mechanical system; such as a beam structure consisting of pivots, rollers, fulcrums and fixed points.
One area of study that is not…
Sam Weston
- 597
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5
votes
2 answers
Effects of constructed tubular/annular beam upon moment of inertia
I would like to construct a hollow beam using either 2"x4" or 2"x6" structural lumber.1 My thought is to take 4 boards and butt them against each other in order to form a square beam2 with a hollow core. The boards would be glued and mechanically…
user16
5
votes
1 answer
Explanation of supersonic flow differences between a 2D wedge and a 3D cone
I know that in case of wedge we have a 2D behavior which creates a discontinuity across the shock, but I am unable to understand why this discontinuity is not present in the case of a conical surface. I have a vague idea that the continuity equation…
Manish
- 247
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