All Questions
16,181
questions
1
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85
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How many kWh this turbine would generate?
My grandfather and I are running some experiments down the river, however we don't have expertise in engineering so I bring up this question to the community and hope someone could help.
How many kWh ...
1
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0
answers
583
views
How does the Xbox Series X "Heat-sink chassis" work?
I understand what a heatsink does, but I cannot wrap my head around how the newly announced Xbox Series X's heat-sink chassis works. From Xbox:
Heat-sink chassis
A heat sink is a non-electronic, ...
1
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0
answers
196
views
Given a BLDC motor with one shaft, where should I attach my encoder?
I have recently purchased an ODrive servo controller made for hobby BLDC motors. Since I had a BLDC motor at home, I did not purchase a dual shaft motor when I got the ODrive.
My question is if I ...
1
vote
0
answers
53
views
Half Sine Impulse in a modal Transient Analysis
I have a MDOF FEM model in which I perform a modal transient analysis based on the modal eigenfrequencies extracted in a prior step.
I wish to excite only the first natural frequency of the system via ...
1
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0
answers
31
views
Permanant extension for Fastener
I have a fastener with an accessibility problem. At the time of installation, the fastener is at the bottom of a crowded box with obstructions varying stiffness (Metal Plates and harnessing). It is ...
1
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0
answers
50
views
Considerations for switching from Conc. Sulphuric acid to Oleum
First off - this project is still in the early planning stages. The basic scope is that a plant want's to switch from using conc. sulphuric acid (~98%) in its process (nitration) to oleum.
I ...
1
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0
answers
552
views
Is surgical and medical mask based on static electricity?
Is surgical and medical mask based on static electricity? By static electricity I mean like 3M N95 mask with at least two different layers of positive and negative static electrical layer. I googled ...
1
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1
answer
562
views
How to calculate the required torque for an azimuth/elevation antenna rotator?
I want to build an antenna rotator for a 1M dish. How do I calculate the required torque for the motor of the elevation axis?
Here's a sketch of the problem:
If the "bottom" of the dish is the pivot ...
1
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0
answers
36
views
flexing operation fails when structure is too long
I have a linear repeat such that for up to 11 repeats, the flex operation works perfectly. for 12 and more, the operation goes haywire. is there an alternate way of doing it that avoids this ...
1
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3
answers
189
views
Some questions about the specific speed (Ns) of hydro turbines
So we all know the basics behind specific speed Ns of hydro-turbines.
$$N_s = RPM \cdot \frac{ \sqrt{(P)} }{ H^{1.25}}$$
where P is the power output and H is the head. The theory is that once you ...
1
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0
answers
130
views
RSS Tolerance calculation and usage
From my experience, I've been calculating RSS tolerances by squaring all relevant tolerances, summing them up and then square rooting the sums... ie: RSS=[Σ(tol^2)]^0.5
I've also heard of other ...
1
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0
answers
231
views
Equivalent moment of inertia in a crank-rocker mechanism
I'm attempting to model a crank-rocker mechanism (see picture). A motor is connected to the crank side and is driving the mechanism with a torque $\tau_{motor}$. A load is attached to the rocker side ...
1
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0
answers
82
views
Launching a ball with springs or with elastic bands
I’m a student and have to create a machine that can launch a small bowling ball to knock over some pins.
I was thinking that I could use elastic potential energy to launch the ball but I’m not sure ...
1
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0
answers
26
views
Standards for safety car seatbelts locking condition
Is there an (international) standard which determines the condition when a car seat belt locks? Which standard is it? Does the standard determines a speed in m/s of the belt, such that it locks if ...
1
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0
answers
167
views
Reference book for hydraulic systems design
I'm looking for a good reference book on the topic of fluid dynamics/hydraulics systems engineering.
I'd like a reference for simlpe/estimate calculations on things like major losses (pipes), minor ...
1
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0
answers
196
views
Wobbling DC motor head
I have used 250 watt DC motor, for DIY electric potters wheel. Motor rated with RPM 3300 and geared reduction to 330 RPM. The issue I am facing is wobbling of the motor head. This issue is with the ...
1
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0
answers
86
views
Bevel gear friction and inertia calculation
I want to calculate the friction and inertia between 2 bevel gears with straight teeth.
I know how to calculate those parameters between regular gears with straight teeth.
Is there any difference for ...
1
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0
answers
25
views
What is the best way to find solved problems similar to the one at hand?
This is a general question, so sorry if it breaks the rules. However, I think it is very important as more often than not someone else has already solved a similar problem that can be applied to solve ...
1
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0
answers
30
views
Slow integration of system ODE under specific conditions in adsorption problem
I am trying to solve the system of ODEs below. I am applying the finite differences to z, so I get a system of ODE that I can solve with a solver like ode45.
The problem is that under the conditions ...
1
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0
answers
95
views
Clutch for high-speed operation (>40 000 rpm)
I'm currently working on a setup where at some operations my motor has to drive a shaft up to the motor's maximum operating speed (12,000rpm) and a torque of ~0.14Nm but at other conditions this shaft ...
1
vote
0
answers
45
views
Is there a standards organization or methodology to determine the elastic material properties of common materials?
Is there a standards organization or methodology to determine the elastic material properties of common materials? What constants are normally used to define these properties?
More specifically, the ...
1
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0
answers
313
views
Tolerance Analysis on clearance holes
I am designing an enclosure that holds a lens (clearance fit) and a photodiode on a PCB. The alignment of the photodiode to the lens must be pretty tight, thus I am using a boss on the enclosure (also ...
1
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0
answers
129
views
Efficiency of harmonic gear drives
Does anyone have application experience with harmonic gear drive efficiencies as opposed to planetary or parallel axis reduction systems?
I'm looking into drives with about a 25:1 reduction, and it ...
1
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0
answers
29
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Water distribution through N x Needle orifices
Consider a water distribution setup consisting of a feeder line blocked at one end but having 100 needle outlets all the same size. The feeder line cross sectional area is much greater than a needle ...
1
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0
answers
26
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Axis connection types
Complete hobbyist here. I have two questions I have a problem figuring out.
I have hard time finding information about axis and types of connections they have. For example take this worm gear reducer: ...
1
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0
answers
322
views
How can I calculate the shear modulus (Gxy) for the material of a composite laminate [10/-10/-10/10] using test data?
I have the data from a tensile test including axial displacement, force, and strain, as well as E1, E2, Nu12, and Nu21 for the carbon fiber prepreg. I am trying to use this axial data to calculate Gxy ...
1
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0
answers
48
views
Calculation for lowering temperature in a room… room-fridge with water mist?
I was looking at how the water cools my body when it evaporates off it. Then I thought the specific heat capacity could be used to calculate how much energy (i.e heat) would be taken out of a room ...
1
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1
answer
23
views
How do cavity resonators differ from tubes of uniform width?
I read that wine bottle produces sound when u blow sideways onto its rim because
some frequencies of the white noise produced in your mouth gets amplified when they match the natural frequency of the ...
1
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0
answers
32
views
How do I correctly model this system of torsion springs?
I am currently designing a symmetric parallel mechanism that can be modeled as follows:
Here, $\tau^j$ denotes actuator moments and $k_i$ are torsion springs constants. For a specific point in the ...
1
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0
answers
79
views
Strut Angle Vs Overhang
I have a 10mm metal disk that is 1mm thick. It is easily bent when a force is applied (green arrow) to the unsupported edge.
I need to add a strut, but at what angle? The part is weight-sensitive, ...
1
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0
answers
63
views
Can any Air rotameter be used for refrigerant gas by using equation conversion?
Currently, I am trying to find rotameter calibrated for R134A gas flow. However, most companies only sell rotameter or variable area flowmeter for water/Air/Nitrogen flow. Is it possible to use any ...
1
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0
answers
221
views
Shore durometer type D to brinells
I saw a video where a person was measuring hardness of a material with Shore durometer type D and was comparing it to steel. The screen on durometer showed 96.5 HD and I was just wondering, how much ...
1
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0
answers
23
views
Why is a mold required in isostatic pressing after performing Sintering
After an a object is formed through direct laser sintering, as a post-processing procedure the object is sent for hot-isostatic pressing, In hot isostatic pressing the sintered object is placed in a ...
1
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0
answers
167
views
Calculating reliability of a parallel redundant system
I'm trying to calculate the reliability of a system that has proven to be a bit more complicated than I thought. Here is the block diagram for the system:
Every single component in this diagram is a ...
1
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0
answers
20
views
Software for Soft Body Dynamics
I am searching for some software to simulate the behaviour of soft bodies like cheese in an quantitive way. For example I want to know the forces in the body during the simulation.
I thought of ...
1
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0
answers
36
views
Solar Radiation Environmental Test Duration
I am designing an outdoor sensor and I need to test it for continuous outdoors service. One of the test I wish to perform is a solar radiation test for the actinic effect (like procedure 2 in MIL-STD-...
1
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0
answers
21
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Questions on Na2Cr2O7 turning to a vapor phase in 2500F furnace. And possible ways, if any, to filter it
I've looked for answers without success, so turn to the experts. At air temperature, solid-phase sodium dichromate (Na2Cr2O7) -- or the equivalent, sodium dichromate dihydrate (Na2Cr2O72H2O) -- is ...
1
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0
answers
28
views
Meaning of SNR in Instrument Specifications
I am evaluating the specifications of an FTIR instrument (Bruker Vertex) and came across the following statements/items:
Signal-to-Noise 5 sec sample, 5 sec reference: >10,000:1 (<4.34 x 10-5
...
1
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0
answers
17
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how to get more number variance compared as the csv output file of two model stl files in Cloudcompare
we are using the CloudCompare for comparing two mouth STL model for Final doctoral theses, like works done in this paper(pdf) shown blow:
and the instruction said here:
so i have tried to insert the ...
1
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0
answers
98
views
In Nastran, how to ignore fatal error due to failed convergence and move on to next subcase?
At the moment the whole analysis stops when 1 subcase fails to converge. How can I keep the analysis going such that all subcases are are run, even if they all might produce an error?
I'm pretty sure ...
1
vote
2
answers
163
views
BJT Output Characteristics Question
Ok, so I am pretty confused at the moment with a question that I have been given to work out by my lecturer and was wondering if I could get some guidance with it. I will attach images of the question ...
1
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0
answers
22
views
how do you calculate viscocity from torque arm load cell measurements?
I have a piece of company developed equipment that uses a pot mounted on a rotating base plate with a 0.15m torque arm and load cell, a mixing paddle is used to stir the mixture while the controller ...
1
vote
0
answers
39
views
Design of fan pipe for propelling glitter
I am trying to create a prototype for a glitter shooting mechanism. It is worth mentioning that I have no experience with mechanical engineering or fluid dynamics. I think the below image describes ...
1
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1
answer
480
views
Static electricity in PE foam rolling
In a PE (polyethylene) foam factory there have been some incidents with static electricity that have created minor fires. Fire is a concern in such a factory, as PE is highly flammable, and even more ...
1
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0
answers
3k
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How to calculate the flow rate of a gas through a pipe?
I am trying to calculate the flow rate of Nitrogen through a cylindrical pipe.
I only need a ballpark value, and the only information I have is the inlet pressure as 15 psig (assuming the same ...
1
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0
answers
57
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I hope this is the correct forum for temperature related question
I have about (this is experimental) 0.75 to 1 liter of water. Ive found I can use 400W of power through peltiers to reduce water flowing through at 1L/minute from 32C to 20C in about 1 to 1.5 minutes ...
1
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1
answer
68
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Does the surface roughness play any role in shock absorbing?
Consider a mass of about $130 \pm 10 $ kg, falls from height, let say $2.5 $ m.
In order to dampen the vibration and sound, I use silencer or drop pads. I was wondering if introducing the macroscopic ...
1
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0
answers
47
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What purpose do the "angled tabs" on a PCIe bracket serve?
In the PCIe specification (see page 75), the "short arm" of the bracket has two cutouts; one for the slot that the retaining screw fits in, and another square cutout that has additionally had the ...
1
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0
answers
25
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Oil pressure inside copper tube?
**Background **
I'm struggling finding how to calculate the pressure that occurs within my system and then once calculated I need to reduce that pressure.
My system
I have a 1 inch copper pipe ...
1
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0
answers
29
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How can I find the length of 12 gauge wire needed for a cone of if I know it's surface area
So I'm working on a personal project, and I need to figure out how much 12 gauge wire (which is ~2mm thick) I would need to cover a cone shaped rubber core, which has a surface area of roughly 3,417,...