# All Questions

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24 views

### Sizing an AC Servo Motor for lifting pallets

I am trying to size a servo motor and my basic physics and math is so rusted that I can't figure out how to go about it? The scenario is as follows: I need to lift an object in the vertical direction ...
19 views

### Meltdown/Spectre attack

What concepts should a newbie(someone who doesn't have too much knowledge about computer architecture, user/kernel space, memory etc.) understand if he wants to know how Metldown/Spectre works? I ...
9 views

### determine the force induced in a rigidly held component that undergoes a change in temperature

A steel bar of length 1m and diameter of 30mm is held in a frame and experiences no stress at 20°C. What will be the stress in the bar if the temperature rises to 80°C and any change in length is ...
62 views

### Driving Gearbox in Reverse

https://www.maxongroup.com/maxon/view/product/251601 https://www.maxongroup.com/maxon/view/product/gear/spur/gs45/301171 Consider that this motor-gearbox combination is backdriven so that the motor ...
12 views

### Complementary sensitivity function in waterbed effect

I am studying the waterbed effect in control systems, and so I have studeird that from the Bode Integral, if I increase the sensitivity to avoid low frequency disturbances, I have amplification of ...
18 views

### Application of thermodynamics [closed]

Air with an initial volume of 0.12m³, pressure 1 bar and temperature 18°C is compressed according to the law pV1.3 = c through a 8:1 compression ratio. It is then allowed to expand isothermally back ...
28 views

### Temperature rise of a block of aluminum under constant heat flux

Consider a block of Al. insulated all around except on one side, where a heat-pipe is to be inserted. On the opposite side of the heat-pipe, there's a heat source (Resistor) with a given heat flux. ...
38 views

### What 's the function of COMP pin(Pin 3) in LM5030 - Push Pull IC?

I'm a student. Now, I am learning to use LM5030 IC to design a Push-Pull converter. So, I read LM5030's datasheet and can not understand the function of COMP pin (Pin 3). The red line is Feedback ...
31 views

### Why do the fan or blower of the Air Conditioner not facing the coil flowing hot liquid?

I observed the fan on external units of air conditioners does not force air towards the hot coil containing hot liquid to make it cooler. Instead it draws air from from the direction of the coil it ...
25 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 ...
16 views

### Circling Morh's Circle (question on tensile stresses)

If I have a mechanical part subjected to a unkown torisional force with the specification that tensile stress should not exceed 150 MPA, how would I form the Morh's circle. I know that I have (150 ...
18 views

### Why does combustion happen at constant pressure in jet engines?

Why does combustion happen at constant pressure in gas turbines but at constant volume in pulsejets? I need to ensure my design adds heat at constant volume. Is it because combustion starts from ...
26 views

### DC Motor with a power supply. How to handle regenerative braking?

I'm currently trying to build a balanced inverted pendulum using a reaction wheel. I bought a motor (12V max 30A), a motor driver (Cytron MD30C) and a power supply (0-24V 30A). My problem is when the ...
24 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 ...
25 views

### Is the Spring Rate for a Belleville Spring Linear?

Belleville disc springs are usually spec'd with a free height, loaded height, and loaded force. From this information you can calculate the average spring rate of a belleville spring. However, what ...
15 views

### Deflection of a Concrete Gabled Roof Beam Simply supported, Uniform Load [closed]

From 0 to L/2 M(x) = 0.5Wx(l-x) Simple support uniform load From 0 to L/2 I(x) = b/12 * [h(o) + {h(0)-h(center)}x/0.5L}]^3 or I(x) = b/12 * [h(0) + .75 h(0)x/L]^3 so I(x) = [b(h(0))^3]/12 * (1 +...
27 views

### US customary units below 1 mil/thou?

I have been asked to provide some of our technical docs in both metric and US units. For the most part, that is easy enough: approx 1cm → approx 1/2" 500μm → 0.02" But then I start getting stuck: ...
39 views

### Impact of Gearbox on Motor Inertia

If you consider a motor attached to a spur gearbox with a reduction ratio of say $r=50:1$ which is then back-driven so that the motor acts as a generator, what would be the effective moment of inertia ...
15 views

### Constain sketch inside block to external elements in solidworks

I am designing a mechanism using sketches and sketch blocks in Solidworks. I have multiple copies of a block that contains a linkage that has a few pivots points. When I edit the sketch in this block,...
17 views

### Control each axis separately - quadcopter

I would like to know why axis can be controlled independently in a quadcopter. I mean, I was told that you can control $x$ and $y$ independently but I couldn't find a demonstration Edit: the ...
25 views

### Is there a technical name for a sound dampening suspended cylinder in loud indoor environments?

Several years ago, I was visiting the Advanced Photon Source at Argonne National Laboratory, and I remember that in one of the working areas there were some large cylinders suspended in the air above ...
11 views

### MATLAB code implementing the Finite Diﬀerence solution of the BVP

I'm having a hard time refiguring this code we used in class to do a 1D finite-difference solution. If anyone could help it would be greatly appreciated. The problem set is listed below as well as the ...
26 views

### What is the maximum achievable throughput of a 4 stages manufacturing facility? [closed]

A manufacturing facility has four stages in series (i.e. every product has to go through each stage in sequence), A-B-C-D with processing rates of 4 units per hour, 5 units per hour, 4 units per hour ...
28 views

### Car trajectory with angled rear wheels (non-Ackerman)

Consider a four-wheel steering vehicle in which: The front wheels follow Ackerman condition The rear wheel are rotated with a fixed angle (dir == dor in the picture below, and such angles do not ...
28 views

### Calculate gas velocity from separator

What would be the best way to calculate velocity of gas from a three phase separator? I know that operating temperature is 75F, pressure 1000 psia, pipe diameter 20 inch, and pipe length to the point ...
14 views

### Creating a low H2O environment at atmospheric pressure

I am designing a reactor chamber in which the environment needs to be N2 at atmospheric pressure. Concentration H2O and O2 needs to be < 1 ppm. To reach and maintain this is not a problem. However,...
28 views

### Reading Motor Datasheet

I'm doing my first machine design for a project and I have a Honda GX160 combustion motor which has the following specs for power and speed: I'd like to use 0.24 HP at 2000 rpm. Is this possible? Or ...
35 views

### Why does this magnetic charger cause short circuit when it sticks to the metal leg of my table?

Recently, I have bought this product. It is basically a USB cable, with a magnetic end, and a tiny attachment that goes into the mobile device. I plugged it into my laptop cooling stand (which has ...
83 views

### Embedded C Programming

I am currently a project intern, working on Light Fidelity (Li-Fi). Most part of the project deals with development of software for Renesas Micro controller. I have a simple doubt regarding timer and ...
35 views

### Limitations on the control effort

I am studying the mixed sensitivity design for control systems, and I have seen that the control effort has limitations given by the bandwidth of the process and by the bandwidth of the sensitivity ...
26 views

### Mechanism to alternate between two lifting ends

I'm thinking of what mechanical mechanism can be used to alternate between two different lifting heads, an adhesive and a non-adhesive side, attached to an arm, so that either head comes forward ...
10 views

### Transient Heat Transfer Problem for a parabolic PDE of Rectangular Plate

I was able to write the elliptic PDE for the steady-state temperature of the plate but I am having a very hard time doing the same for the transient problem. Now consider the transient problem for ...
17 views

### Getting From 3D a model to CNC router

Apologies if this is not the correct SE for this sort of question. But, this is the only place I've seen an appreciable number of CAD questions. If this isn't appropriate for engineering.se, a pointer ...
29 views

### Calculate the second moment of area around y-axis

In an exercise on my engineering class, I have to calculate the moment of area around y-axis (the horizontal one). There is a very small (negligible) gap at the middle of the semi-circular arc, and ...
17 views

### Calculating Entropy from Gibbs Free Energy?

I guess Cp = dH/dT= dq/dT=dS Thus SdT = integral of CpdT. From that ∆H is given and we can calculate ∆G. However, entropy for this reaction should be -7.4J/molK and I am getting like 26J/molK. Also S ...
25 views

### Design compensator to improve yaw rate control performance for aircraft

I am trying to design a compensator to improve the yaw rate ($\dot{r}$) control performance of an aircraft. The lateral dynamics for this aircraft is given in steady space form as following: where A (...
31 views

### How to build an online payment gateway? [closed]

I and my team are planning to built a payment gateway. We understand the roles of a payment gateway, that is, to authorize a card-not-present transaction and securely send the transaction details with ...
29 views

### abnormal behavior in electronic throttle control module [closed]

I have an electronic throttle control module. I get different outputs each time by giving the same electrical input. Does anyone know that what is the reason for this abnormal behavior?
13 views

### There is a system with 2 working and 1 standby chillers(3 x 225 TR) which is connected to 520 TR of load. How is this possible?

How does redundancy work in HVAC? There are two working chillers of 225 TR each and one standy chiller of 225 TR which is serving units totalling to 520 TR? Can i actually connect units upto 560.5 of ...
12 views

### Calculate Scattering Parameters - RF Circuits

Can someone explain how to calculate scattering parameters for the circuit pictured. I need s12&S21. The answer is 1/3 but don't know it's obtained. s11=s22 =1/3. Za = 50 ohm Zb = 50 ohm Zc = ...
20 views

### Control effort in mixed sensitivity design

I am dealing with mixed sensitivity controller design in SISO systems and I am comparing this approch with the classic approch. In particular, I have placed a weight for the sensitivity function in ...
37 views

### Etymology of the term “journal bearing”

Typically the word "journal" refers to a collection of written records, experiences, or transactions. However, there is a common type of bearing known as a sleeve bearing, radial bearing, or journal ...
17 views

### Stability with eigenvalues' real part equal to zero

I know, from Lyapunov criteria, that a system is stable (not asymptotically) if the system has eigenvalues with negative real part or it has eigenvalues with real part equals to zero, but in this case ...
27 views

### Precipitation Hardening

Please explain the meaning of this statement with close reference to Precipitation hardening,"The relative rates of nucleation and growth are controlled by temperature. The size and dispersion of the ...
16 views

### Relationship between conjugate poles and resonance peak in frequency response

I have two root locus of two closed loop transfer fuctions, which differ just by a different value of the gain. I have that the one with a larger gain has a reasonance peak bigger in the frequency ...
20 views

### PWM -electronic solenoid valve

I want to control the flow of chemical proportionate to the forward speed of the vehicle( if the speed is more discharge is more vice-versa). Need to integrate vehicle speed with encoder and control ...
11 views

### Design concept, how to power a guage?

I have a 12V battery that I want to monitor using a fuel gauge IC, should the fuel gauge be powered by the 12V battery? Or something else? (can you please provide an example if so?)
33 views

### Is a Geodesic Dome (fuller dome) that floats possible? What material or engineering effort would it take?

Buckminster Fuller has popularized Geodesic Domes (invented by Dr. Walther Bauersfeld who based it on the use of convex polyhedrons), and thus, making buildings with a very large roofs that don't ...
13 views

### Gradient-free optimal control solver?

I have a dynamics simulation that provides the state derivative $\dot x = f(x,u)$, implemented in C. I'd like to solve the optimal control problem (given an initial state and cost function). Because ...
25 views

### what does 0.1% FS +/- 0.02 mean?

Let's assume a DMM is specified to have accuracy "0.1% FS +/-0.02" when used on the 50 V range. I get that 0.1% FS means the true value will lie somewhere between measured value - 0.05 and measured ...

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