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2 answers
Controllability of $x' = Ax + Bu(t)$ implies controllability of $\left \{ \begin{matrix} x' = Ax + By \\ y'=u(t) \end{matrix} \right.$
Suppose that the system
$$x'(t)=Ax(t)+Bu(t)$$
is controllable in $\mathbb{R}^n$, where $A$ is $n \times n$, $B$ is $ n \times m$ and $u(t)$ is $m \times 1$
Show that the system
$$\left \{ \begin{array}{rclccc} x'(t) &=& Ax(t) &+& By(t)& \\…
Giiovanna
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6
votes
1 answer
Why use steam in the rankine cycle?
In the rankine cycle, water is first pressurized and then heated to produce steam before it is used to turn a turbine. As far as i know, this is what is considered the best way to extract mechanical work on the turbine, but i want to understand why…
Paul
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6
votes
2 answers
How to build a winning Pumpkin Derby racer?
At the large hotel where I work in the engineering department the big Halloween event is the annual Pumpkin Derby...and we've lost every year to the culinary department. It's embarrasing!
This year, though, we caught them in the act. Since they're…
ehbowen
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6
votes
5 answers
Could a mainspring be used to generate train acceleration during starting-up from the kinetic energy stored during its slowing down?
When waiting for the underground, I've always been wondering why we could not absorb the kinetic energy of the train to slow it down at the station and then to release this energy to help it accelerating during the starting up. This would also…
Noil
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6
votes
1 answer
Where to insulate Underfloor air distribution system in a temperate climate
I have a proposed underfloor air distribution system (UFAD) for a one level office in a temperate climate. Typically the demand for heating and cooling in this climate is about even for offices. However the building is well insulated and has a fair…
pandita
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6
votes
3 answers
What is the densest ceramic?
I know ceramics are generally considerably less dense than pure metals or alloys but sand is used in barbells for its probably cheapness, user-friendly and easy availability but its a decent density too. rammed sand- 1682 kg/m cubed using…
user2617804
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6
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1 answer
Is there a difference in cast vs extruded acrylic with regards to how they appear in x-rays?
I'm working on the experimental apparatus of an extension of this paper: https://arxiv.org/ftp/arxiv/papers/2110/2110.09017.pdf
We basically have to make a bucket using an acrylic tube. My question is, if I put an acrylic (or other plastic) tube…
user9807390
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6
votes
3 answers
Why do modern diesel electric submarines predominantly use lead acid batteries?
I have always wondered why the diesel electric submarine industry has not kept pace with the consumer market for high power/energy density batteries. We have seen a historical transition from lead acid, to nickel-metal hydride, to lithium ion…
Alex Popescu
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6
votes
2 answers
Can the production rate of labs-on-a-chip ever reach the production rate of silicon chips?
Labs-on-a-chip and silicon chips both have the potential - and in some cases have already reached the potential - to drastically scale down tasks, in these cases performing chemical reactions and performing computations.
Part of the appeal of…
HDE 226868
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6
votes
3 answers
Mounting and Coupling an Encoder
I was wondering how to mount a small rotary encoder to a platform in order to measure how far a small treaded robot has traveled. We're using this tread/wheel set:
We've tried epoxying the encoder shaft directly to the end of an extra gear wheel,…
rasz
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6
votes
3 answers
Meaning of quarter hole color fill in drawing
In this drawing 4 of the holes have the top left quarter filled in black.
What is the meaning of that? It it some special type of hole?
The drawing is from a Waveguide and in the specs it says
Flange type FDP32 (Cover)
So I'm thinking it might be…
Elerium115
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6
votes
3 answers
Why are flyovers/metro rail tracks much higher than traffic?
To pick a specific example, a flyover that goes over a ground-level road/rail need only be as tall so that the tallest vehicle travelling in the outermost lane can clear it.
Or another, an elevated road/metro rail that runs along a ground-level road…
Jesvin Jose
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6
votes
1 answer
What does a higher eject force do in a clutch?
I am looking at two clutches and the details on both are identical. The only difference is the eject force. One is 3300 and one is 3600. Does a higher eject force mean higher performance? And also does it have any drawbacks? Like is the clutch…
Rafael Dias
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6
votes
2 answers
Limitations of the cut-off ratio in real-world diesel engines
In an ideal diesel cycle, the cut-off ratio is set by the maximum gas temperature after combustion. That's all fine and good, but in a real-world engine what controls the cut-off ratio, and what are the limits to its flexibility? I feel like it must…
Murenrb
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6
votes
4 answers
What is the use of gears in a device with a fixed gear ratio?
From my understanding, there are two uses of a gearing system: to change the speed of output rotation (trading it with torque), and to change the axis of rotation. Now, in a car, for example, it is necessary to have multiple available gear ratios,…
Karnivaurus
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