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34 views

Where should I study contact mechanics (for introductory level)

I am MAthematics and MEchanical Engineering student and this is my senior year. For reserch and personal interest, I need to learn about contact mechanics. From where I should start and what is the ...
16 views

Doubt regarding meta-stable and labile region of a supersaturated solution

I have read in a paper that the for formation of new crystals in a solution the energy released due to formation of solid from solution should be more than the energy needed to overcome solid-liquid ...
33 views

Which kind/model of sensor is appropriate for detecting vibration at one end of 1000 m steel block?

We have to detect vibration/sound produced at rail track for upcoming train at 1000 m distances . So which sensor is appropriate here? thanks.
19 views

What exactly makes reaction turbines work?

I was reading about reaction turbines on Wikipedia, it says: "Reaction turbines develop torque by reacting to the gas or fluid's pressure or mass. The pressure of the gas or fluid changes as it passes ...
31 views

Avoid loosen of a cartridge valve caused by embedding

This problem is (mainly) caused by the small clamping length. And this clamping length is predefined through the standardized cavities – exemplary I mention ISO 7789. Of course you can raise your ...
10 views

Which version of the Kozeny-Carman equation is valid?

I am learning fluid mechanics, and I've come across the Kozeny-Carman equation for a packed bed in laminar flow conditions as: \frac{\Delta P}{L}=\frac{150\bar{v_0}\mu}{\phi^2D_p^2}\frac{(1-\...
55 views

What is this weird upside down U shaped pipline for?

There is this tall upside down shaped U pipe near a sugar refinery on Maui and I can't figure out what it's for ? I've also see these in other industrial areas near salt flats.
33 views

What pressure is taken as the pressure of liquid

I am learning pure substances in thermodynamics.I read a sentence "Consider a piston cylinder containing liquid at 20 degree celsius and 1 atm pressure."My question is that the pressure of liquid ...
43 views

Calculating the torque required by an Archimedes screw pump

Given an Archimedes screw pump (shown below) how would you go about calculating the torque required to operate it? I'm assuming a situation where you have to design for a given flow rate, Q (m^3/s) ...
62 views

Changing fields from mathematics to control engineering [closed]

I did my undergraduate in maths and physics and will be working in control theory for my future job. Not to my surprise, my engineering background is rather lacking. I have taken a look at materials ...
645 views

What causes a fastener to lock?

I am rebuilding a car engine. With some of the fasteners I am unscrewing, I notice that a lot of torque is required to undo the fastener. It feels like a snap when undoing a fastener, rather than a ...
19 views

Wall temperature of pressure cylinder - Boundary condition

I have a thick-walled pressure cylinder, that transports fluid and experiences only internal pressure. During the process, the outer wall temperature is measured. And I have no clue about the inner ...
26 views

How do i measure the time taken for a laser to cut a metal?

I am a placement student and was given a project asking to measure the time taken for the laser to cut a metal and send it to Excel into a spreadsheet automatically. I am a computer science student ...
12 views

Anyone facing issues with a compact roller press machine?

I am currently facing a problem with the machine above. When I try to compress something using the roller machine, sometimes my sample will have "scratch" marks after coming out. There are no foreign ...
21 views

Springs on a pulley… When to use?

I saw a machine that fed a sheet of laminate through some rollers. The motor had a pulley attached to its shaft, and a spring connected to the pulley. Why not use a belt? Wouldnt the spring make it ...
10 views

How to ensure uniaxal and uniform force application on uneven samples using pressurized fluids

I am trying to apply a compression force to samples using air. I do not want to directly apply my loading since my samples are irregular. I do not wish to process them with a flattening step. I hope ...
7 views

How slip is calculated in the Abaqus small-sliding interaction?

I’m doing research on the sliding of 2 fracture surfaces. To do that, I’m trying to understand the Small-sliding deformable interaction in the Abaqus (2018), and I use the Node-to-surface ...
16 views

“bubbles” forming after heating my Thin film transistors

I am fabricating Bottom gate Thin-film-Transistors. The Gate is 60nm Molibdenum. The dielectric structure changes with the table below. The temperature represent the annealing temperature after ...
38 views

Persistent Bistate Toggle Switch

I'm a noob if it comes to electronic components but I'm trying to achieve the following and I would really appreciate some suggestions: I have the following requirement: When a circuit is closed the ...
24 views

Can i switch negative feedback to positive feedback in PID control?

I am learning Control Theory and i have a confusion about whether the following PID controllers are interchangeable or similar. Are they equivalent? Why? Is there any difference in how i would ...
143 views

Why is a cart with swiveling casters in front stable, but not if the swiveling casters are in back?

Consider a four-wheeled cart that has swiveling casters for the two front wheels, and has wheels that don't swivel in back. For example, a common shopping cart, or trolley if you prefer. If such a ...
15 views

Help finding connector to fit 1 3/8in / 35mm mounting flange on horn driver

My project is a DIY talkbox using Monacor KU-516 compression driver. I'm having a hard time finding the right connector to fit the hose to the driver, M35 is a rare size it seems. There's one ...
22 views

How do I verify the reaction forces of an FE model due to a response spectrum

In the case of a static calculation of a structural model, one can verify the model by checking the applied and reacting forces to be equal zero. I would like to adapt the same principle for a ...
41 views

How are tight coiled springs made

SOme tight coiled springs are made so that they are already under tension - how do they manufacture them?
77 views

Is the center hole important on car wheels?

I came across with this discussion about this topic, however it doesn't address the answer clearly. What is the safety role of center hole (A) on the vehicle ...
30 views

What type of pump is recommended for pumping gasoline/petrol in vapor phase?

I would really like to know your input, perhaps there are regulations on this that I'm not aware of that can help out regarding the overall safety of the process.
57 views

Can a rod be attached perpendicular to the motor shaft

So, I was trying to make something like this . However, While I have the motor, the motor has a vertical shaft and I need something to connect a rod to it in a T shape Is this even possible? And ...
54 views

Is this a PID cascade control loop?

I'm working on a balancing robot. I'm familiar with the simple PID control loop but i can't understand this PID control loop. Is this actually a cascade control loop? The programming states that the ...
28 views

How to derive fixed-end moment of a beam?

Here is my attempt but I am not getting the right answer. Can someone tell me what I am doing wrong?
43 views

Material to absorb very low frequency radio

Is there any material that will absorb very low frequency radio light? I know that stealth aircraft use radar absorbant materials in their design that absorb radio light best at certain frequencies, ...
14 views

best refractory cement for embedded heating element furnace

first post I designed a 2000 watts 1000 degrees Celsius furnace with following chamber size: 11 cm length, 12 cm width and 15 cm depth. The refractory that I use is 1880 C high temp tabular alumina ...
88 views

What does “do not scale drawing” in a drawing sheet mean?

I opened a new sheet in Solidworks drawing, in the title block, there was a field written "Do not scale drawing". What does that mean? There is a scale already being chosen over there. It was just a ...
34 views

Deciding between Electric or Hydraulic Actuators for a Dynamic Load of around 4 kN to 6 kN

This is a project regarding linear actuators for a 4 Wheeled Robot, with spider like hinged legs. The first question on my mind was to figure out is if a hydraulic system has any weight to Force(...
44 views

Clutch role in a micro hydropower

I've recently visited an old (about 60 years old) micro hydroelectric standalone installation. Total electric power is about 3 kW A/C. A local told me between generator + fly-wheel and turbine there ...
26 views

How can I transmit signals from pre-amplifiers to a laptop nearby using bluetooth?

I am trying to collect signals from preamplifiers (Aquarian Audio preamps, PA-4) and have them sent to a laptop nearby wirelessly, I have not found a dedicated device for this process, and the ...
15 views

Valve advice for chiller test rig

I am in the process of designing a chiller test rig, of which a very simplified diagram would be (the quick coupling might just be replaced by a non-return valve): I am struggling to find the type of ...
14 views

How can I validate the validity of a model of a dynamical system?

I derived a non linear differential equation system for a mechanical system. However I doubt the correctness of it. So I compared the model's dynamics with a VREP simulation. I did this by by Euler ...
24 views

Handling internal hinges (releases) in a FEA Buckling Analysis

Background I am running a FEA linear buckling analysis according to the equation $K_e x − \lambda K_g x = 0$ where $K_e$ is the global elastic stiffness matrix and $K_g$ is the global geometric ...
15 views

Check valve for high frequency oscillating flow

I have a closed cylinder with pressurized gas that undergoes rapid pressure oscillations at around 50-150Hz, and amplitudes in the order of 1-10kPa. I want to connect a check valve so that some gas ...
24 views

why can't remove the Image frequency using a band-pass filter?

why can't remove the Image frequency using a band-pass filter? I've been asked to search for the reason why we can't use BPF (band-pass filter) in order to remove the effects of the Image frequency? I'...
11 views

Aspen cost estimation

I'm currently simulating a plant for biofuels production, part of the job is to estimate the costs associated to the construction of the plant, as well as energy consumption cost, etc. However, I am ...
28 views

What does stress analysis of 3D printed parts reveal vs their normal counterparts?

I have seen videos or heard about 3D printed buildings, 3D printed space shuttle parts and more. There seems to be a lot of craze developing around 3D printed manufacturing. I have never heard anyone ...
26 views

Pump placement for watercooling project

So, I have this weird project in mind for water cooling a computer: Putting a water reservoir, pump and a radiator right on top of my roof (it's a flat roof) and having pipes to connect that to the PC....
71 views

Heat Transfer in Different Wire Configurations

I am trying to create a program which estimates the final temperature of a magnet made of copper wire. I have different configurations in mind, but I will start off with a straight square wire with a ...
37 views

How effective are pancake motors as generators and why

Using a motor as a generator but looking to test something Why would or would they not be good generators thanks
44 views

Negative transmit power in dBM

I am calculating the transmit power for $K$ single antenna IoT devices in an Indoor scenario. The receiver has 64 antennas. I am trying to minimize the transmit sum-power, i.e., $\sum_k p_k$, where \$...
15 views

Choosing a pump to inject liquid into a pressurised water pipe

I'm interested in using a pump to inject liquid into a mains water pipe (3-6 bar pressure) I don't know what pump to use as they all seem too big for the task they are carrying out. I want to use a ...
11 views

How to prevent leakage radiation from a grid of inductors laying on a plane?

I am thinking of designing a large wireless charging pad/table.The idea is to have many inductors in a grid setup, where when a phone is placed on the pad/table it starts charging from the inductors ...