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1500 questions
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votes
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Where do the tributary angles/ratios for tributary areas come from?
When preparing load calculations for a slab, the quick method is to define the tributary areas of a slab for the beams/columns below. These are generally taken as lines at mid-span of the slab panels and, depending on the support conditions, at the…
SlydeRule
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Determine the sign of torques for a planetary gear system
I am trying to calculate the power distribution of a planetary gear system, specifically a Wolfrom system like this one:
In order to find the output power, I need to find the torque for the rings 5 and 6. Torque and angular velocity of the sun 1 is…
user3130648
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1 answer
How do you create a chamfer in 3D CAD that joins the edges of two different shapes?
I am trying to make a 3D model. It consists of a cylinder resting on an extruded ellipse as you can see in the picture below. I now want to join the top edge of the ellipse with the top edge of the circle. In a sense, I want there to be a chamfer…
PJazz
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How can I tell if a gear is pressed or threaded?
I recently bought my first lathe (A circa 50s PREMO, Australian built with tapered roller bearings) and the spindle has a little bit of wiggle parallel to the axis of the spindle. I decided to pull the spindle out to take a look at 'er, but I ran…
Rob M
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How to calculate the velocity of a piston-like linkage?
I ve tried to solve this problem in so many ways but still didn't manage to do it...
What would be the correct way to solve it please?
This arm of this mechanism has a length of 0,2m. The piston has an angular velocity of 2000 tours/min. What would…
privetDruzia
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1 answer
First principle derivation for torsional constant
For torsional constant, analytical formulas are available for some standard steel sections as shown in this wiki page.
But what about arbitrary shapes? How can I obtain the formulas for torsional constants? If no such formulas are available, are…
Graviton
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5
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2 answers
What are 'inside' and 'outside' dimensions in reference to castings?
I am looking at a company-written standard for cast parts. The castings are blanks for driveshaft yokes, similar to what is pictured below. The standard defines general tolerances for the dimensions on the part, and it classifies them into two…
Trevor Archibald
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How do DC motor parameters scale with motor size?
Consider the following DC motor parameters:
Rotor resistance, $R\ [\Omega]$
Motor constant, $k_t\ [\mathrm{V/rpm}]$
Inertia, $I\ [\mathrm{kg\cdot m^2]}$
How do they scale with motor size? Do $R$ and $k_t$ depend on $I$?
Karlo
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votes
2 answers
How to evaluate new Vernier calipers?
I am looking to purchase some new Vernier calipers, but I am overwhelmed by the amount of specs which are being offered. I need help in understanding how to evaluate them.
I do not want a dial or digital set of calipers, but rather am interested in…
RobertBarington
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5
votes
1 answer
What are the technical differences between flexible and rigid solar panels?
During a recent search I discovered the existence of flexible solar panels. Besides the obvious differences of low weight and flexibility what are the high level technical differences between flexible and rigid solar panels? What is the typical Lux…
Mahendra Gunawardena
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votes
2 answers
How much air gap is required in a storm pipe?
I'm studying the design of storm sewers and I had two questions relating to air gaps in storm pipes:
According to sources I've come across, flow through storm pipes
require an air gap so as to maintain open channel flow. Do I need to
maintain a…
AlfaZulu
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How to model heat transfer through a pressure vessel wall if the reservoir temperature is not constant
I have a closed cylinder with a gas inside at 3,000 K.
I want to find the temperature profile (over time) through the cylinder wall, something like figure (b) shown below:
In my case, however, $T_\infty$ does not stay fixed at 3,000 K over time…
Davide
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5
votes
1 answer
How long does it take for two initially seperate fluids to reach a certain homogenity across their container?
Imagine the following initial condition:
Two completely miscible fluids A and B with different dynamic viscosities $\eta_A$ and $\eta_B$ are seperated in a container with fixed Volume $V_0$ and length $L$. The temperature $T_e$ is constant across…
JHK
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5
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1 answer
Convert 60hz 120Vrms to 24khz 120Vrms
I would like to create an interface that increases the frequency out of the wall, 60 hz, to 24khz. I have chosen 24khz as the operating frequency of an induction heater I am planning on building and I would like some advice as to how I should go…
Toroid Tank
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5
votes
1 answer
Third Rail vs Overhead Cable: which is more efficient in terms of electricity consumption?
I'm well aware that there are many different factors to be considered, such as ease of installation/maintenance, conversion from AC to DC, environment, distance, speed, frequency of turns, and so forth.
Setting all of those aside for now, suppose we…
Ricky
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