# All Questions

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801 views

### Remote start on a car with manual transmission

I'm making a remote starter for a car using a Raspberry Pi. The problem is that the car has a manual transmission. The driver needs to remember to place the gear shift in neutral when parking, ...
352 views

### mass calculation from transfer function or bodeplot

I have a double mass rotary model. The two masses are connected by an axis which together acts as a spring damper system of the fourth order. The system is actuated by a motor and the angle of ...
1k views

### What is the densest ceramic?

I know ceramics are generally considerably less dense than pure metals or alloys but sand is used in barbells for its probably cheapness, user-friendly and easy availability but its a decent density ...
1k views

### Truss manufacturer drawings unclear

I am currently looking at a set of truss layouts produced by our truss manufacturing partner for a residential building project. I have reason to believe these layouts are generated using Alpine (...
427 views

### Differential equation of the vertical displacement of a cable

Given a cable (totally flexible) fixed at both ends, subjected to a vertical force $f(x)$ in his plane, with variable area $A(x)$, and variable elasticity $E(x)$ I want to find the differential ...
7k views

### What method can I use to make a pivot point in an aluminum linkage?

I recently had a project where I made an aluminum linkage (similar to a scissor lift) operated by linear actuators. Aluminum pieces were fabricated from 6061 "standard" aluminum stock, 6mm (0.25 inch) ...
4k views

### How is the long-term creep of a spring determined?

Spring Design In spring design, there a a variety of parameters to consider. Some of the parameters are solely physical (wire diameter, coil diameter, length, etc.) and some are determined from the ...
1k views

### Why do bluetooth headsets get interference (choppy sound quality) outdoors?

This is more of a general physics question to help me understand how to choose sports headsets in the future, however it is too specific to a certain use case (bluetooth headset) to belong in the ...
2k views

### Involute Gear Calculation

I've written a program to generate gears and write them to dxf files. I thought all was well until I looked at the mesh of two gears. From everything I've read there should be no backlash when the ...
72 views

### What diameter of particles will result in a blocked borehole?

My mine is looking to install a 600 mm open borehole to drop particles up to 150 mm through. It's a 320m shaft to drop ballast down to save time compared to using the drift. When it gets blocked ...
4k views

I know that with strain-hardening you increase the yield and tensile strength. So if you unload at point D, then you also have cold worked it a bit right? So the stress-strain curve will look ...
414 views

### Fluid mechanics - how to calculate flow distribution in piping network?

I am trying to build flexible, visual tool to calculate flow distribution through the piping network (mobile hydraulics). I have root node of the network which has defined flow and pressure inputs. ...
698 views

### Estimating Maximum Speed for a Pneumatic Cylinder

I am designing an machine that is going to use a pneumatic cylinder to accelerate a projectile. I have a tentative cylinder specified, and am working on the control and supply side. I have verified ...
508 views

### 6082 Aluminium softened by brazing. How to harden?

I've started playing around with brazing pieces of extruded aluminium sections to join them together for strong joins as an alternative to bolting them. The pieces are made of 6082-T6 aluminium alloy....
2k views

### Deriving the deflection force equation for a beam that is fixed on both ends

I want to calculate the force-displacement equation for a beam that is fixed at both ends. I think I should use the superposition principle but I am not very sure how to get started. I know that for,...
2k views

### How an airfoil works

I have read on many sites that for lift to occur, the pressure below a wing must be higher than the pressure above it. This happens by somehow moving air faster over the top of the air foil so the ...
188 views

### How small can you get a stream of molten steel to be at low pressure?

I'm designing a crucible / extruder, and right now it has a .6mm hole to extrude from. Will this work? A chart with various metals listed would be nice. Pictures: Click to expand
14k views

### What does “beam end release” actually mean, and how it is modeled in mathematical terms?

I am reading a document about beam end release here: An end release will allow either or both ends of a beam element to rotate about or translate along one or more of the local axes of the beam....
1k views

### Minimum thicknesses of an elliptical cylinder pressure vessel

For pressure vessels in the shape of circular cylinders, we can use $\sigma_{hoop}=\frac{pr}{t}$ to find the minimum skin thickness by setting the hoop stress the maximum allowed value, and then ...
2k views

### Losses through holes drilled in a pipe

I asked a previous question about pipe t-junctions with pipes of varying diameters, and it got me wondering... How are losses handled and calculated in pipes with holes drilled directly into them? ...
598 views

### How to find angle of timing gears

I am trying to figure out how to calculate either the distance or angle of 2 Idler Gears in a Timing Gear Configuration like so: I have been able to eyeball things, so they are approximate. I would ...
8k views

### Steel Structure connection pin or fixed

For the connection above, I think that once the beam is loaded, their is no room for rotation of the beam. But as per British Standard this is a pinned connection. So I have been trying to determine ...
7k views

### Properties of an hexagonal shape vs round tube shape

In a bike frame build, are there any differences between hexagonal cross-section tube instead of the typical round tubes? Assuming that both are made from the same aluminium alloy and have the same ...
447 views

### Is there a theoretical bound to how tall a structure can be built?

Assuming that there are no constraints on cost, land to develop, or supply of materials, is there a theoretical limit on how tall a structure can be built? What are the main physical constraints that ...
270 views

Suppose we have a horizontal rigid bar hinged at one end to the wall. An inclined straight link hinged at one end to the same wall, is pinned to the rigid bar at its center. A load P is acting at the ...
472 views

### How to calculate the steering ratios on multiple axle vehicles?

I'm building a model of a long vehicle with 6 axles and I want to be able to steer it. How do I calculate the amount each axle should steer to minimise dragging of some wheels round sideways as it ...
810 views

### How can I attach a rotary encoder to a retractable dog lead?

I need to know how I can attach a rotary encoder to something string/wire that I can pull and it retracts automatically My idea was to take apart a retractable dog lead leash and affix it to it ...
581 views

### Gear coupling and clearance between pitch surfaces

I have a couple of spur gears (0.4 mm module, ISO8/AGMA9 precision, 24 and 120 teeth). I want to make their backlash as small as possible. But also I don't want them to jam. Where can I get the normal ...
94 views

### How can I make an uncalibrated flow meter for water flows of a few liters per hour

Or alternately what is the name of the device I'm looking for? My first thought is to make a narrow V shaped chamber by gluing 1/4" acrylic together with 2 face plates and a mid plate with a ...
65 views

### How does a pressure vessel fail when the interal pressure exceeds the yield stress of the material?

When we design a pipe or pressure vessel, we look at hoop stress and longitudinal stress and then look at the material properties. We assume that the material reacts to the load as a solid. However ...
32k views

### Difference between Saturated Liquid and Saturated Steam

I have a (maybe stupid) question which is making me crazy: what is the difference between a saturated steam and saturated liquid state? I mean the physical difference not the difference on a ...
271 views

### what's the best shape for inducing condensation?

What would be the best ceiling shape for inducing condensation? I'm guessing it would a curve ︶ or V shape, but those are just guesses. (I don't have any background on thermal physics)
65 views

### Does the Hyperloop One suspension require constant current through copper windings?

As a follow-up to How does the pressurized suspension of the Hyperloop not affect the tube pressure?, I believe (though I can't find where I read it now) that the Virgin Hyperloop One implementation ...
2k views

### Oldham coupling vs Universal joint

I've heard that both of these coupling types introduce a degree of kinematic error in the driven shaft. What does it actually mean in practice? Is it that the driven shaft doesn't turn uniformly even ...
72 views

### What does (a) the input of the activation function mean?

I am not very good at understanding the ANN theory, but please if anyone can explain me about what does (a) as input of the activation function mean? and how to get this value? Thank you
486 views

### Flow in a T-Junction with pipes of different diameters

I have been trying to model a complex pipe network recently and have come across something I can't find any information on. In my model, I have been assigning equivalent lengths of pipe to various ...
195 views

### Why/how normal shear stress is zero in thin-walled beams?

Please explain how the normal shear stress (shear stress normal to the cuve, C, defining the cross-section of a thin-walled beam) is zero. I have attached a screenshot from a book which says that the ...
944 views

### Can anyone verify this wall thickness of a pressure cooker?

I am working on designing a pressure cooker. I've have tried to find, using two different models, the wall thickness based on the following assumptions: Cylindrically shaped container Made of ...
97 views

### Is there a device like this? [closed]

I would like to get my hands on a mechanically-set timer (wind up is fine, so that it's self-powered) which sends a small electrical pulse to a mag-lock once the timer goes off, thus causing the mag-...
57 views

### How to derive phase equillibrium criteria for more than 2 phases mathematically?

I know the derivation of phase equilibrium criteria derivation for 2 phases. I am not getting how to extend the derivation to more than 2 phases. Please help me out on that. Thank you
2k views

### How much force can a pole in ground take before falling?

Consider I have a pole stuck in the ground as illustrated below: When a force F1 is exerted on the pole, its bottom end will push against the ground it's stuck in; the ground then exerts a resistance ...
65 views

### Find optimal configuration for Stirling Engine

I'm trying to figure out the theoretical calculations for a Stirling Engine system so I can determine optimal piston size, optimal piston displacement and number of pistons. I want to calculate which ...
258 views

### How to obtain strain and stress values by editing abaqus input file?

I am currently working on abaqus modeling, I am trying to find a quick way to get the strain and stress values shown in the output file. What do I need to put in the .inp file? Does anyone know how ...
91 views

### What does this equation mean?

$$\propto \dfrac {\text {Cross-Sectional Area}}{\text {Volume}}$$ I've seen this equation on my textbook (physics). Let us imagine that there are two pen with $7$ and $3$ lenght. Which is harder ...
60 views

### how to avoid a clash of magnetic charge and electric charge

now I'm working on a project which involves a dc motor and high voltage. I'm developing a machine consists of a motor to rotate a platform disc and high voltage will be applied during the rotation. ...
1k views

This is the question, but with me 6 kN/m is 4 kN/m and 2 kN/m is 2.5 kN/m. And the length is not 4 but 9 metres. I am not yet at the chapter of equations of equilibrium, plus it says the couple ...
5k views

### How to prevent deposition of dust on ceiling fan blades

It is well known that dust gets deposited on a rotating ceiling fan because formation of a boundary layer over fan blades. The air layer next to blade surface is stagnant due to no-slip condition and ...
2k views

### Could a gold/{second metal} crown be created that would pass the Archimedes test cost effectively?

Many people are familiar with the story of Archimedes submerging a crown in water to identify if the volume of the crown was consistent with the volume of the same amount of gold. The test was to see ...