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How much do I need to trickle my faucet in cold weather (as a function of x,y,z)?

I am told that, in cold weather, I should let my faucet trickle a little to prevent pipes from freezing, especially if some portion of my above-ground pipes are likely to get cold. Are there any rules ...
0
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0answers
4 views

How do I reduce the mains spike in a switched mode PSU?

I have a switched-mode PSU for a gaming laptop. It has a bad habit of burning out the switches on mains extension panels when I turn it on (two in the last four days). The turn-on surge is always ...
0
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0answers
8 views

Increase in internal energy and temperature

A banquet hall (150 m3) is to be used for a formal dinner for 20 persons. Each person occupies 0.075 m3 of space and has an average heat transfer rate of 500 kJ/hr. If the AC system fails, determine ...
1
vote
1answer
12 views

Why is the thin-walled cylinder more likely to experience failure along its axis than along its hoop/circumference?

I was watching the YouTube video: https://www.youtube.com/watch?reload=9&v=Ja03J1RQ3Hw to understand the concepts of hoop/circumferential stress and axial/longitudinal stress in thin-walled ...
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0answers
15 views

On servo loops bandwidth and tracking

Referring to article https://www.controldesign.com/articles/2018/servo-terminology-makes-a-difference/ I was unable to understand how loop gain influences the noise rejection and tracking. Taking ...
0
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0answers
10 views

Best PID autotuning algorithm/library for simple heater problem

It's the 21st century, anything is possible. Except for PID autotuning for a simple problem, heating/cooling system - make robust and ready to use solution. I've found only one library for PID ...
0
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0answers
9 views

How do I model the ELEGOO robot car?

This is the robot car in question. The car is made up of the following sub-systems: DC motor driver subsystem, where the input is the PWM signal from a microcontroller (for example), and the output ...
0
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1answer
20 views

Drum-brake self-adjusters

I was reading about Automotive Brakes (Chapter 52, Automotive Mechanics by William H Crouse, Donald L Anglin, 10th edition). And in a section about drum-brake self-adjusters, it is said that the ...
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0answers
15 views

How can the spinning arms of a dishwasher be leakproof?

Recently I was wondering, how it is possible, that the spinning arms of i.e. a dishwasher or a high pressure cleaner can form a leakproof connection from the fixed watersupply to the nozzle on the ...
4
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2answers
41 views

Why aircraft refrigeration uses a centrifugal compressor in place of reciprocating compressor?

Why aircraft refrigeration uses a centrifugal compressor in place of reciprocating compressor and a gas turbine in place of reciprocating expander?
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0answers
26 views

Vertical Distance Measurement Sensor between Railway Bogie and Track

Need to find a Displacement Sensor with following details: I need to place a displacement sensor that continuously measures vertical gap between a railway carriage and the track. That is, a beam is ...
1
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0answers
59 views

What is the amount of force that will cause failure?

What is the amount of force required to cause the beam to deflect, shear or otherwise fail? The force would be generated by a hydraulic piston. Let's call those units PSI. The piston will be mounted ...
0
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1answer
26 views

What is the difference between requirements and design specifications?

Working while employed at large companies, I was at times confused as to what was considered to be a requirement and how a specification differs from it. Upon reading more about it, I have discovered ...
-2
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0answers
18 views

Is it allowed to have conflicting design requirements? [closed]

Is it ok to have conflicting design requirements?
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0answers
9 views

Tangent matrix terms in Abaqus UEL

I have problems in the calculation of the tangent matrix terms in an Abaqus UEL subroutines, do you have suggestion on how to take tensor derivatives? For example: $$ \frac{d\underline{\underline{T}}}{...
0
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1answer
41 views

Meaning of flow rate in water pump

Rated flow in the following is in conjunction with the rated lift meaning it can lift 15 meters at flow of 12 Liter/ minutes from a well? But what if its sucking water from the water company with ...
0
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0answers
14 views

RF Engineering - Cascading a 3 Port S-Parameter Network into a 4-Port S-Parameter network

I have been trying to cascade a 3-port scattering parameter network into a 4-port scattering parameter network that will ultimately be terminated by another 3-port network (as can be seen below). The ...
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0answers
20 views

Using Density Correction Factors for Fans and Blowers

I've been researching fans/blowers and their use in pneumatic systems (particularly conveying systems), and I'm confused by the application of density correction factors. Let me describe a sample ...
1
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0answers
26 views

Is my understanding of the roles of transistors in this circuit correct?

THE CIRCUIT'S FUNCTIONING This circuit is a rain water sensor circuit that buzzes when there's water on a probe.I found it on net.1 CIRCUIT COMPONENTS 3 Volts Battery BC 558 Transistor(PNP) BC 548 ...
2
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2answers
47 views

Does venturi effect helps in reducing temperature of a room?

I clearly didn't understand how this works, but the explanation and claim that it reduce the temperature of room by 5°c made me wonder, here I am trying to understand the Venturi-effect on temperature ...
0
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1answer
39 views

Temperature controller using pt-1000 sensor

I need to control the temperature of a system with high accuracy with error value of $0.1$ degrees celsius +-. I will be using temperature sensor PT-1000. I need to know what would be the best option ...
0
votes
1answer
12 views

How to log turbocharger's compressor flow data?

A turbocharger's compressor map has a graph with Pressure Ratio on the y axis and Compressor Flow (lbs/min) on the x axis. The pressure ratio can be measured using absolute pressure sensors located on ...
1
vote
2answers
50 views

What does it mean for a machine design to be “kinematic”?

I've seen the term "kinematic" used qualitatively to describe machines several times in books and on YouTube. I think I understand what kinematics is as a study, but I'm not sure what people ...
1
vote
1answer
22 views

Friction versus ratcheting pawl

We are working to design a lock mechanism and need to hold a square plunger out of a hole for extended periods of time (potentially years). The square plunger is under pressure from springs to return ...
1
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4answers
39 views

Are there tools to select the best material based on their functions?

I'm working on a small engineer project and I need to know which materials are candidate depending on their functions. For example, I needed a material for a part of the machine that need to be ...
17
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6answers
3k views

How can I measure correctly with a ruler?

When measuring with a ruler divided into mm lines, should I include the lines by themselves or only in between them? I illustrated the problem. (I took an example of measuring of 10 mm with two long ...
-2
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0answers
20 views

Effect of air and water at different pressures on vessel weight

Consider the current average pressure at sea level to be approximately 1 bar = 100 kPa. The mass of air at 1 bar absolute (0 bar gauge) is 1.275 kg/m$^3$ The mass of water at 1 bar absolute (0 bar ...
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0answers
27 views

How many spheres are on the surface? [closed]

I have asked this question in both the physics and math sections but have not gotten an answer in three years. If you have 100 identical spheres and group them into A sphere shape, how many will be on ...
0
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0answers
23 views

Stewart platform 6DOF parrallel manipulator static force diagram

I am trying to develop a statics free body diagram of a stewart platform 6dof parallel manipulator motion table. I have the base points (B1,B2,B3,B4,B5,B6) and the top platform points (P1,P2,P3,P4,P5,...
0
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2answers
61 views

250W 24V Motors

(please note that this is a duplicate of a question the electrical forum, however, there are some mechanical subjects that would be better suited here.) I am trying to make an electric go-kart. I am ...
0
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1answer
21 views

Does having a basement level increase overall earthquake resistance of a high rise building?

Does having a basement level increase overall earthquake resistance of a high rise building? Does it also lessen the burden on pile foundations?
0
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0answers
11 views

Modelling a rough surface of Ti6Al4V alloy in LAMMPS

I am trying to use LAMMPS molecular dynamics software to model the surface topography of a Ti6Al4V alloy that was created using a selective laser sintering process. This is to model the asperity and ...
0
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0answers
19 views

How to accurately use the approximation formula in a ritz approximation?

I have been able to do all the steps required in the question poised in the problem below to get to The issue I am running into is trying to use to actually obtain values to obtain numbers for my ...
0
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1answer
35 views

How to calculate the open-loop transfer function with disturbance at the input of the plant

I have the system as follows: I am trying to find the transfer function: $$ T(s) = \frac{Y(s)}{U(s)}$$ where $Y(s)$ is the output and $U(s)$ is the input of the plant. The plant is $H(s)$. I have got ...
1
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0answers
16 views

Low temperature flexible polymers

I'm working on a design project that will require a flexible component that will be operating at temperatures from $0^{\circ}$C to $-200^{\circ}$C. Are there any thermoplastic polymers that remain ...
1
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0answers
15 views

Sutherland's law for other gasses

Sutherland's Law seems to be a fairly well-accepted relationship between dynamic viscosity and temperature and was originally created to work for ideal gases, though it is often extended to be used ...
1
vote
2answers
181 views

How to add friction to a rope without using abrasion

I have a pay-out winch. It is a spool of rope that has a disk brake attached to it, so I can control the torque required to rotate the spool. When the torque is very large, however, the rope begins ...
0
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0answers
15 views

Effect of wind on ultrasound sensor

For example, if I have an ultrasoundsensor 1 m above the ground while there is a wind speed of 5 m/s, a rough estimate of the horizontal displacement of the beam would be $$ t \approx 2 \frac{1}{343} =...
2
votes
1answer
34 views

Maximum hole size in brickwork before a lintel is required

Holes are made in brickwork walls for all kinds of reasons including gas flues, to route cabling and to fit windows. At some point that hole gets large enough that a lintel is required to support the ...
1
vote
1answer
37 views

Bending stiffness of composite shaft

What is the method to compute the effective bending stiffness "EI" of a composite structure, in this case a shaft (as seen below). The shaft is hollow with outer radius $r_{o}$, inner radius ...
2
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2answers
45 views

Probability of structural failure

In structural engineering we have to accept the fact that you can never be exactly sure how much load a structural member can resist, that the load carrying capability of an element is not one exact ...
0
votes
1answer
28 views

Determine the bandwidth of a closed loop system [closed]

The unity feedback system with loop transfer function is given as $G_c(s)G(s) = \dfrac{50}{s(s+40)}$. Determine the bandwidth of the closed loop system. options 6.4 rad/sec 3.2 rad/sec 12.8 rad/sec 1....
0
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0answers
5 views

Heat-generating surface not exactly overlapping with TEC cold plate - loss estimate

I have to cool an optical element (drawn as the black rectangle in the figure shown below) using a TEC, with the cold plate drawn in gray in the figure below, including screw holes). 95 percent of the ...
0
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0answers
21 views

Roll Forming Process

The roller for our application is in contact with the aluminium extrusion as shown in figure 1, highlighted by the black box. Considering the in-homogeneous deformation, when there is no friction ...
0
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0answers
26 views

How do I combine multiple asynchronous motors? [closed]

Im not an engineer or even studying so thanks for the help and understanding. If I have a lot of motors all with different power & rpm how do I combine the power of all of it and drive a motor ( ...
0
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0answers
33 views

what is the name of this wheel found in toys which rotates freely?

I have tried doing search by image on few popular Internet search engines but could not get it. (sorry, it picked up lot of dust and a bit ugly to see). I want to know the name of such wheel and where ...
0
votes
1answer
16 views

Stress Concentration: Hole in infinite thin plate loaded in biaxial tension vs biaxial compression

Is there a difference in the stress concentration of a hole in an infinite thin plate loaded in biaxial tension vs biaxial compression? I ask because in numerous books (one of them in the screenshot ...
0
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0answers
18 views

Are there any manufacturers of thin sheets of ferromagnetic materials?

Are there any manufacturers of thin sheets of ferromagnetic materials? The sheets only need to be up to around 60 mm * 200 mm, and field strength up to around 3mT. This is to build a transducer, so as ...
0
votes
0answers
13 views

How to trace a square with a reuleaux triangle

I am trying to trace a square (with rounded corners) using a reuleaux triangle and a single (circular rotation) motor. I've seen many animations (example) of this but do not understand how to make it. ...
0
votes
0answers
16 views

Calculating kWh two-phase alternating network 3 wires

I want to do a project to measure electrical consumption but I have the following question: How to calculate kWh consumed in a 3-wire biphasic network? Example: I have the following chains on the ...

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