Pete W
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5 answers
1 votes
402 views
Are un-dimensioned orthographic views permitted on a standard drawing?
4 votes

Regarding the issue of repeat dimensions, at least for machine drawings as opposed to structural, reference dimensions (either in parentheses, or indicated like "12.34 REF") could be an ...

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1 answers
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25 views
What are some chemical reactions that failed to scale up?
1 votes

'Failed to scale up' can be a commercial thing as much as technological, will comment on that. Typically for anything novel, companies will file some but not all patents before they have ...

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1 answers
1 votes
75 views
Resistive divider hydraulics analogy, is this true?
1 votes

With laminar flow (and some other assumptions like fully developed flow, everything at equilibrium, newtonian fluids, and uniform viscosity throughout the system), then Poiseuille's law applies and ...

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2 answers
1 votes
85 views
V2 drawing interpretation
2 votes

I haven't seen that form of tolerancing, but your suggestion makes sense, that it might be min / nominal / max ; and min / max when only two numbers. I would also say same side as arrow. ...

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3 answers
0 votes
58 views
Why materials with preferably a negative temperature coefficient for heating elements?
3 votes

It really depends. If you have multiple heating elements (or areas within a single element), in parallel, they will end up at slightly different temperatures. If the application is temperature limited,...

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2 answers
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62 views
How to tune a PID controller when plant's step response looks like a ramp?
1 votes

If the response is really a ramp, i.e., a single integrator, you could use a P or PI controller. If the ship has some mass to her, then the ship's turn does not start or stop immediately -- rudder ...

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2 answers
1 votes
36 views
Control System Response
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Picking up from NMech's answer: For the step response, integration constants can be expressed in terms of $\zeta$ and $\omega_0$ According to swarthmore.edu Where $\omega_0 = \sqrt{\omega_1\omega_2}$ ...

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1 answers
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51 views
Could someone explain how a compensator shifts the root locus?
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0 votes

If I read it correctly (i.e. the plant has a single zero but not pole at the origin), then the issue I think is being solved, is that the plant RHP pole we are trying to manipulate is unpaired. Thus ...

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3 answers
4 votes
225 views
Equivalent viscous damper for friction damping
1 votes

I think a hydraulic device could approximate it. General concept: For each direction: a spring-loaded check valve (ie with a cracking pressure) in series with a small-diameter-tube would realize a ...

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2 answers
1 votes
64 views
What, roughly, are the characteristics of nuclear power in grid management?
1 votes

Re: load following, from Wikipedia Modern nuclear plants with light water reactors are designed to have maneuvering capabilities in the 30-100% range with 5%/minute slope. Nuclear power plants in ...

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3 answers
0 votes
84 views
Is electric motor torque determined by Kv or by power (watts)
1 votes

Kv is for back EMF. It is part of what you need to model the current, in addition to the resistive and inductive model of the motor windings. The current then gives your torque via Kt. This is all to ...

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6 answers
9 votes
2k views
How to work on big CAD project in team?
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12 votes

It's a massively important question. Short response: apply the concept of encapsulation. Divide into subsystems During development, assign design-ownership (distinct from project manager role, ...

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3 answers
3 votes
388 views
Highest point of stress in a multistage gear reducer
1 votes

As per the other answers, when teeth are uniform width, and are engaged, then pressure and shear-stress should generally be highest on the slowest moving gear. There are also impact loads as they ...

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2 answers
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29 views
Force control of pneumatic piston
1 votes

For a quantitative application, the electronic pressure regulator in Transistor's answer is probably the most appealing other than component cost. (It may still need another valve to move backwards, ...

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2 answers
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52 views
Discrete-time realization for continuous time domain controller/filter?
1 votes

For a great many engineering uses, you can approximate your idealized s-plane filter, into a z-plane equivalent, by one of the transformations mentioned in AJN's answer, using closed-form "...

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2 answers
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111 views
Aluminum or Copper, which one is better to control and maintain the temperature?
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2 votes

Simplified analysis to compare materials, for different limiting-case applications, given the same geometry: Want max heating ramp rate, with fixed-power electric heater -- minimize Volumetric Heat (...

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1 answers
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65 views
Ideal Surface finish in turning
1 votes

Simple definition of depth of cut, I believe, is the nominal difference in radius of the work before vs after the cut. This would be the roughness only when the Z feed rate was equal to (the "...

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2 answers
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55 views
How do I get a thin section slice of grooved metal to analyze groove depth under a microscope?
4 votes

There may be non-destructive options, like laser profilometers or even optical microscopy that can extract Z axis data. Check the back side too.

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4 answers
4 votes
121 views
Engineering Best Practice: Rev control for trial parts after release?
2 votes

When I worked at an (in theory) ISO shop, we did the same thing as the OP, and in-development designs were uncontrolled and informally and inconsistently versioned. A recent question here (talking ...

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3 answers
3 votes
268 views
Given flow rate of an orifice at one pressure, how do I calculate flow rate for a different pressure?
3 votes

Here is a reference from RoyMech, see section under "Orifice Flow Meter". The setup has the orifice placed in a pipe. Below is a similar, perhaps simpler, expression, from Jobson 1955, part ...

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1 answers
2 votes
35 views
Applying PSO for tuning a compensator for double integrator plant
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This doesn't address the optimization, but is a follow-up to the comment about the system itself. Below are the 2 qualitative scenarios for a lead compensator with a double-integrator plant. In the ...

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1 answers
0 votes
66 views
How would I drop something directly in the middle of a vertical pipe?
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4 votes

Illustration following up from the comments We used vacuum to hold the ball bearing being dropped, from above. The ball was hand placed up against the output port of a manifold. Around it was open air....

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3 answers
3 votes
150 views
Fun Force Problem - Basic Structure of Two beams supporting weight
2 votes

To follow up on answer by NMech: I suspect if this were built, it would be necessary to have tension adjustment, due to elasticity of the tarp. Then, the sag and any 3D "catenary type" shape ...

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3 answers
4 votes
910 views
Control theory: Closed loop zeros, Root locus and its dynamic response
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Late answer here. Zeros can have a significant effect on CL (closed loop) response. If they are within the bandwidth of the loop, they would cause overshoot in the step response. The CL stability is ...

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2 answers
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85 views
Response time and time constant of Mercury thermometer
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I'd guess specifying the response in a different way. The typical first order unit step response is an exponential decay, $1-e^{-t/T}$ where $T$ is the time constant. The value of the expression after ...

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2 answers
4 votes
93 views
Get average shape from 10k + files
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hmm. here's a shot in the dark. might require relatively simple surface. this is crude, the are much more sophisticated ways. research metric or distance for 3D shapes. (1) In a 3D modeling tool, ...

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2 answers
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74 views
How do I read this schematic drawing notation for a drill hole?
2 votes

To expand on comments: This drawing is a little bit sloppy. As it's a clearance hole, it should just indicate thru diameter and both diameter and depth of cbore. Takes almost no effort in any remotely ...

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1 answers
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21 views
Specific CO2-Emissions of Natural Gas & Hydrogen Mix
1 votes

assuming full combustion, CO2 coming out is none from the H2 1:1 mole ratio from the CH4 So mass of CO2 = ( mass of CH4 ) x ( molar mass of CO2 ) / ( molar mass of CH4) Add a slight adjustment for ...

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2 answers
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36 views
Question on fluid flow measurement uncertainty
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In series would usually be best, with two caveats: the setup has to be such that the upstream meter does not affect the downstream meter, either systematically or by adding noise. if the total flow ...

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2 answers
1 votes
97 views
How to determine the force to empty a syringe containing high-viscosity fluid?
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Hard to say. Although the pressure is very high (up to 5kN/0.001m^2 = 5MPa), the velocity is super slow and Reynolds number is very low, deep laminar region. I wouldn't worry too much about roughness. ...

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