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5
votes
1answer
52 views

What makes a pulley that is rated for horizontal pulling different from a pulley rated for lifting?

I have a home project that involves lifting a platform with a cable that runs through a series of pulleys to redirect the cable. I'm selecting pulleys for the job and I see that some pulleys are rated ...
0
votes
1answer
414 views

What's the best way to design a joint with two fasteners?

When you're trying to design a relatively long joint with only two fasteners, what's the best way to arrange them? Since fasteners effectively radiate a circle of clamping force around them, what's ...
0
votes
0answers
36 views

Why don't engineers put tesla valves in the airboxes of carbureted internal combustion engines?

Before I ask the full question, I want to quickly cover two common issues that come up in high performance engine design. When intake valves close in an engine a small shockwave moves backwards ...
2
votes
0answers
36 views

Why funnelling air in order to increase the velocity is a bad idea when generating power

Disclaimer: I’m not trying to violate the conservation of energy here; I know that’s impossible for us mortals. I think I’m either wrong or not considering something, I just want someone to point it ...
1
vote
1answer
40 views

How to set measure display units in Solidworks drawing?

I have already set millimeters in document propertis, nevertheless the display units are meters Why and how to fix?
2
votes
1answer
36 views

Is there a concept of gain and phase margin for a strictly open-loop transfer function?

I'm new to control systems, and I'm attempting to analyze the stability of an open-loop transfer function. I know that by checking the locations of the poles (and ensuring all poles are in the LHP) I ...
-1
votes
0answers
28 views

Despite high fuel economy , why Diesel engine produce more pollutants (NOx)?

Diesel engine are effective in terms of fuel economy compared to petrol engine and emits less CO2, However they produce high amounts of NO2 and other harmful substances, Ideal maximum temperature of ...
1
vote
1answer
59 views

How can I get final value of $V_{out}$ at $t=∞$ in RC circuit?

I can obtain the transfer function in this RC circuit. $$ \frac{V_{out}}{V_{in}} = \frac{1}{(RCs+1)} $$ When $V_{in}$ is set to $10V$, how can I get final value of $V_{out}$ at $t=∞$? I tried to use ...
1
vote
0answers
26 views

Is it practical to increase engine efficiency by preheating petrol from engine heat waste ? is it applied in any automobile?

I found some article related to preheating the fuel to increase fuel efficiency, but I rarely see such implementation, I assume that it's less effective compared to others But is it really possible ...
-1
votes
0answers
12 views

If I have equations for the dew/bubble point curves, and I know the pressure and enthalpy, can I find the temperature and quality of the mixture?

As mentioned, I have equations for both the dew and bubble point curves, T(P) or P(T) and also rho(T), rho(P). I also know the actual pressure, and enthalpy of the liquid-gas mixture. Is this enough ...
0
votes
1answer
26 views

How to choose correct motor for my application?

I'm looking to play around with making a massage pad that I can lie down on and has massage nubs that are motor driven. There will be a motor that rotates the nub (the part that does the actual ...
1
vote
1answer
44 views

What would be the best mechanism to rotate a plate from 0 to 15 degrees?

I'm designing a machine in a small university project that change position of a two-state gate. The two states shown in the Figure below are 0 and 17 degrees of elevation, correspondingly. The ...
-1
votes
1answer
33 views

Why do I have uncertainty in my dimension in Solidworks?

I drew part and added some dimension on overall model and got value with uncertainty Why and how to fix?
1
vote
0answers
13 views

Unable to multiply the part along the same axis as rotate in SolidWorks

I am trying to multiply part with Linera Pattern and have each instance rotated by 180 degrees. Unfortunately, I can't specify the same axis for both rotation and ...
-1
votes
0answers
15 views

Kinematics of omnidirectional robot (Kuka YouBot)

I want to control YouBot in Coppeliasim through ROS. So, I started to search about the kinematics of omnidirectional robots. I found good information on the book of "Modern Robotics" by ...
-1
votes
0answers
18 views

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
votes
1answer
34 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 ...
1
vote
0answers
31 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 ...
2
votes
2answers
65 views

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

I was watching a YouTube video to understand the concepts of hoop/circumferential stress and axial/longitudinal stress in thin-walled cylinders and their formula derivation. So the formula of the ...
-1
votes
1answer
38 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
votes
1answer
37 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 ...
1
vote
1answer
27 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 ...
-1
votes
0answers
29 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 ...
6
votes
2answers
80 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?
-1
votes
0answers
33 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 ...
0
votes
0answers
77 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 ...
-1
votes
2answers
49 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 ...
-1
votes
0answers
13 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
votes
1answer
80 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 ...
1
vote
0answers
16 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 ...
0
votes
0answers
26 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 ...
0
votes
0answers
32 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 ...
1
vote
2answers
61 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 ...
-1
votes
1answer
49 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
24 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 ...
0
votes
2answers
54 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 ...
2
votes
1answer
24 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 ...
2
votes
4answers
48 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
votes
7answers
4k 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 ...
-1
votes
1answer
31 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,...
-1
votes
2answers
68 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 ...
-1
votes
1answer
30 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?
-1
votes
1answer
41 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 ...
2
votes
0answers
18 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 ...
2
votes
0answers
21 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 ...
2
votes
2answers
197 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
votes
0answers
24 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} =...
3
votes
1answer
51 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 ...
0
votes
1answer
41 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 ...
3
votes
2answers
53 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 ...

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