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59 views

How can I build a electronically controlled valve for a 1/4 inch tube

I'm looking for a practical efficient way to open and close a 1/4 inch gravity fed hose. Initially I was thinking of using a Solenoid, but can't find anything suitable. My second thought was using a ...
1k views

How to calculate deflection of a cantilever beam subject to point loading

I am trying to solve the following beam deflection problem: The cantilever beam is subjected to the point load at C. Generate the equation for the elastic curve by using the double ...
37 views

How do Test Indicator Flexible Holders hold rigidly when tightened?

If one were to search on Amazon for "Test Indicator Flexible Holders" you will turn up many items using this mechanism (please ignore the magnetic base; I'm not focusing on that part, just the red ...
223 views

Whistle Design - Optimizing sound initiation pressure and volume

Assume you can use any whistle type, is there a way to choose the pressure point at which a whistle makes noise? For example I have a whistle that starts making noise at 2 psi but I would like to ...
77 views

qualitative influence line of pinned support

For the highlighted part , why we need to replace the support at A with a roller guide ? We could see at A , it's a pinned support , right ? Pinned support will resist horizontal and vertical ...
882 views

Conjugate beam (M/EI)

I dont understand how the diagram of M/EI of conjugate beam drawn , can someone explain about it ? According to conjugate beam theorem , i know that the M/EI represent the w(x) , which is force per ...
46 views

What changes can be made to a whistle to change these variables? [closed]

I have read that the longer the whistle the lower the pitch and the shorter the whistle the higher the pitch. But there are other factors. Pressure, size of the inlet, size of the outlet, diameter of ...
136 views

How to determine heat exchanger equation?

What is the equation to determine the inside surface temperature along the length of the counter flow heat exchanger?
962 views

How does Hysteresis in tires helps create friction?

I am currently reading “Fundamentals Of Vehicle Dynamics” by Thomas D. Gillespie. The author states how tires generate the required frictional forces for movement by 2 methods : 1)Hysteresis 2)...
33 views

Inefficiency of intermittent burn in rockets

Imagine I have a combustion chamber with a nozzle. There is a high pressure oxygen bottle and a high pressure gaseous fuel bottle connected to the chamber. Would the fuel efficiency be lower if I ...
83 views

How to calculate residual strength of a corroded structure from their stress values?

Currently, I have an actual entire corroded bridge model in the FEM analysis in Abaqus I want to estimate the residual strength of this bridge due to corrosion from the output results in the Abaqus, I ...
136 views

Easy model to calculate water flow rate over trough ledge?

Trough is 1.87 meters long and 0.5 meter wide and 0.22 meter deep. Water only flows over the 1.87 meter long side and from both sides (so x2). The water overflow is 0.012 meters tall (ruler ...
94 views

For an at-grade intersection of multi-lane roads, the "Turborotonde" (Dutch language Wikipedia article) or "Turboplein" (Dutch language wegenwiki article) is an alternative to the multi-lane ...
228 views

Shear Stress Formula

Could anyone tell me what the variables in this formula are? $$\tau=\frac{S\;a\; \bar{v}}{I\; t}$$ I believe it is used for shear stress and that $I$ is moment of inertia but unsure on the other ...
73 views

Using a Copper Waterblock or Aluminum Heatsink to Cool Water via Thermo Electric Cooler [closed]

I am attempting to create a ThermoElectric Cooler to Chill Water. I have thought of two options as to how I can cool the water: Some limitations of the design: The water is still, not moving. No "...
284 views

Is continuous beam design deemed “unsafe” by any code of practice/design practice for reinforced concrete building structures?

I am asking this because some of my engineer friends said that they won't want to analyze beam as continuous beam for RC building structures, because it is "unsafe" to do so, whether it has anything ...
33 views

Why torsional warping does not occur for shafts with circular symmetry?

When we twist a shaft/beam/rod, shearing stresses are produced. The angle by which the end of the shaft rotates can be found as: $${\displaystyle \theta ={\frac {TL}{GJ}}}$$ where $T$ is torque, $L$ ...
2k views

Sizing plate washers for through-bolting to concrete

We are working on some equipment that is going to be attached to existing, 3,000 psi reinforced concrete floor slabs. In some locations, the best way to do this is to through-bolt and 'sandwich' the ...
148 views

Looking for a formula that states the stiffness of a composite [closed]

I am looking for a formula that states the breaking point of a composite - How much pressure it can withstand before it 'snaps'. Specifically I am looking for a formula that states the materials ...
62 views

Oscillations in motor control systems

I have an underdamped control system for a DC motor. It is only a mathematical model so I can't visualise the motor. I can change the value of the "k" or compensator. I have noticed that changing ...
35 views

Can e-paper capsules be made larger in size?

Can I buy individual (larger in size) e-paper capsules from somewhere? (for an electronics project for example) and is it even possible for such large e-paper capsules to be engineered?
35 views

How many heaters needed

A room 10"x10"x17" lxbxh respectively to be heated 397F if a heater is placed inside the room (2 kw) how many heater are to be required to heat the room from room temperature to 397 F in 1 hour.
56 views

Reinforced mesh at different distance in a concrete slab?

Trying to determine some information regarding the reinforced concrete slabs (reinforced with mesh) in an apartment, by looking through the holes in the middle of the rooms for lights, I've come ...
22 views

How would I go about charging titanium dioxide for e-paper technology project?

I'm experimenting with rubbing a balloon on a silk (to get the electrons) and then touching the balloon to two small aluminium foil balls to see if they'll repel but they don't (if I do it with ...
68 views

Rule of thumb for choosing a best sampling rate

I have a discrete control system with known dead time and time constant, where a process variable is sampled at regular discrete time intervals and fed back to the controller. I want to find out an ...
65 views

Simple Thermal Analysis for sealed Aluminum box with 3.7 Watts of heat generation internally

I am looking for a starting back of the envelope calculation to determine if an aluminum box with just free convection can dissipate 3.7W of internal heat generation or if I need to think about adding ...
50 views

Regarding automotive engine mounts

How are automotive engine mounts tuned to behave differently for different frequencies, like they are soft for high frequency low amplitude vibrations and hard for low frequency high amplitude ...
22 views

0..360 constrained rotation mechanism

I'm looking for examples of mechanisms that can constrain a hub rotating around a shaft from 0 to 360 degrees. Rotation between 0 and 360 should be free. Rotation < 0 and > 360 should be stopped. ...
30 views

Is there an easy way to calculate carrier output of a planetary gear set which has two inputs?

Online I found many guides and videos on how to calculate outputs of a planetary gearset but all of them have only one input. But how can I calculate output speed of carrier if ring and sun gear are ...
40 views

what is the range of the measurable relative elasticity with a commonly used strain gauge

I'm looking for a data that what is the typical application range for a common uni directional strain gauge like used in weight scales? I've read about around 200 ppm in a research gate article, can ...
44 views

Time to change temperature inside the box

I have an interesting problem here. I have a box of certain dimensions. Inside of the box is some insulation and another box, from the same material as the outer box. I know everything possible about ...
269 views

Calculation for heat transfer rate / cooling capacity for air cooled solid

I have a pipe which is channeling air flow from a compressor with a known mass flow rate and temperature. I can adjust the mass flow rate (power setting) and measure the delta T for the temp of air ...
27 views

Is this is a valid estimation for the mass flow required for Hyperloop air-bearings?

In Hyperloop air bearings, the air escapes through the rear cross-sectional area of each ski, you know? Yes, there is a pressure differential, but the air comes out of the skis, crashes into the tube ...
2k views

Mechanisms to convert linear motion to rotation

These are the mechanisms I'm aware of: Crankshaft Scotch yoke cam-shaft wobble drive (a.k.a nutator or Z-crank) swash-plate What are other mechanisms to convert linear motion to rotation?
54 views

Measuring Current In/Out of Resistors [closed]

The banana clips attach to a multi-meter out of view, the power supply wires are correctly in place, and the resistors are correctly in place. Would putting the red left-hand banana clip and its ...
559 views

How to calculate external pressure resistance in spheres and cylinders?

Although I have seen a lot of literature online about how internal pressure resistance is calculated (i.e the pressure in a gas tank) I haven't found anything about the opposite scenario (i.e the ...
164 views

Push / Pull Steering on an axle

I have a base with 4 wheels, the rear axle is a motor which drives the base forward or backwards, this contains a diff, so there's no problem there. The front axle is a steering axle like that in a ...
32 views

max shear act on point

Why we need to consider only 3 cases when we want to find the max positive shear ? IMO , We know that the max shear will only occur when the 67.5kN act on B , am i right ? There is no need to consider ...
835 views

What is the reason for a reduction in entropy in a compressor

I was under the impression that the entropy reduction in a system only works with either mass or heat transfer. While I was researching intercooling of compressors I stumbled across a peculiar ...
48 views

If I use clay tempering, can I take a thin piece of steel and make it hard as a very thick piece? [closed]

If I use the forging process of clay tempering, can I take a thinner piece of steel and and make it as strong as a very thick piece of steel? Getting the same strength, without the extra weight?
103 views

rotating mirror system for shifting a beam?

I am looking for some mirror setup where rotation one or more elements in the mirror setup will allow to shift the beam along its axis. Two mirrors in a galvanometer scanner type setup work well for ...
2k views

shear stress at nail at different points [closed]

In this notes , i dont understand how the Q=(Ay) of the is considered ... I think the both Q at part C and part B should be = (60)(15)(mm^2) ... i have redrawn the structure , i am not sure whether ...
286 views

Pump power and fluid viscosity

I used to calculate the power needed by a pump using Bernoulli equation, $W =(p_2-p_1) + {1 \over 2}\rho(u_2^2-u_1^2) + g\rho(h_2-h_1) + R$ where $\rho$ is fluid density (and assuming it is ...
1k views

Is the mass flow rate constant in a thermodynamic cycle?

Is the mass flow rate constant in a thermodynamic cycle? More specifically a Rankine or Carnot cycle. For example if the mass flow rate of the turbine is 100 kg/s, is the mass flow rate for the ...
141 views

Thick walled cylinder theory - Stress/strain in ballooned out tube

I want to work out how much I can expand a piece of rubber tubing before it ruptures. The wall is 0.75mm and the ID 5mm. Hence I am working out the stress/strain from thick-walled cylinder theory ...
33 views

Can I lift 15 tons on air bearings with 0.2 kg air/s?

The air is at 13 kPa and 400 K. I can raise both the supply temperature and the pressure if necessary. No problem with that. I could get 1.7 kg/s for the air bearings, but I have no more air. I ...
38 views

Are there any turborotonde / turboplein designs with more than four exits?

For an at-grade intersection of multi-lane roads, the "Turborotonde" (Dutch language Wikipedia article) or "Turboplein" (Dutch language wegenwiki article) is an alternative to the multi-lane ...
90 views

Is a granite block tunnel longer lasting than reinforced concrete? [closed]

Assumptions Building Process exists Waterproofing is able to be replaced Notes Please answer yes or no with the science backing. This question is only about the strength and lifespan. This ...