# All Questions

7,361 questions
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### Help me Solve this Steady State 2-D Heat equation

So I tried to solve this PDE by separation of variables which was not applicable because of non-homogeneous nature of this PDE. Then I assumed ( after reading from a book ) :  T(x,y)=v(x,y) + \phi(...
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### What are the design principles for risers in sand casting?

Risers are added reservoirs used to feed liquid metal to solidifying casting. In the case of alloys that shrink during solidification (this is not the case of all alloys), one uses such reservoirs to ...
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### How can batteries in electric cars charge at such a high rate?

If I were to look at "normal" batteries online, they often have charging C-rates of much less than 1. However, with an electric car that uses regenerative braking, obviously such a low charging rate ...
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### Is a 1/8" AR400F steel plate strong enough, for 4,000 lbs?

I have a Ford F350 cab & chassis and a gooseneck trailer. For the gooseneck hitch I want to use a steel plate. The steel plate will be BOLTED to the frame, above the rear axle And the gooseneck ...
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### How to design a coaxial 1:2 gear without reversing direction?

I am trying to design a gear that has a 1:2 speed ratio (input:output). This design is very limited in space and for simplicity and space savings requires the input and output shafts to be coaxial. ...
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### What Is the Different Between Single Nipple, Double Nipple, and Pipe Nipple

I just work on the engineering company that specialize in water piping. I am confuse about the term of nipple. What is the different between Single Nipple, Double Nipple, and Pipe Nipple? Hope ...
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### Is there a motor design where a rotor gradually moves into a stater?

I was wondering if there is a motor/generator design where the rotor moves gradually in and out of the stator along the axis of rotation, or the stator over the rotor. If so, I'd like some resource(s)...
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### Is there a formula to relate the axial length of a nozzle expander with its radius?

I know the inlet, throat and outlet areas for a nozzle expander. Is there a formula to know its axial length? Something like L= f(A) = f(D).
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### What height is needed to drop a 72 kg mass to impart a 5000g shock onto a test piece

I am trying to design a simple drop / shock testing machine. We want to rate our products to be shock rated to 5000g. In order to test our products to 5000g I plan on dropping a weight onto the ...
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### What equation are we using to describe forces in FEA?

Engineers often use Finite Element Analysis software to solve for stresses inside complicated structures to generate pictures like the one above. I am familiar with FEA as a method to solve ...
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### Using a rotational latch to restrain an object under a horizontal force

So hypothetically, I'd like a to build a latching system to prevent a steel block experiencing a horizontal force from moving until another upwards force releases a latch, at which point it would ...
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### About method of work and Energy or Clapeyron theorem

I'm having some difficulty to understand the work and Energy method (aka Clapeyron theorem), especially with different loads. Could you please help me to fix this problem, because I found different ...
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### the volume in hydraulic retention time is of reactor/container or liquid

I have a tiny reactor, and the volume I need is 425ml. If there is no/few other reactants, then the volume in hydraulic retention time is clear: reactor/container's ...
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### Which mounting bracket to use with a geared box?

Which 90 degree bracket would you use for this one? Do you have any suggestions for what i should be looking for, I find it very hard to find something. It is 5cm between all the outer holes. Would ...
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### Refute my assumption: Bearings Don't Improve Efficiency

If two surfaces rub together with a normal force between them, friction is generated. You could add lubrication between those two surfaces and reduce that friction. Bearings essentially consist of ...
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### What kind of splines should be used when planning roads?

I would like to plan a small road network for an imaginary city, and I am looking for a way to create curved road segments. I am familiar with cubic Bezier curves, but I am not sure if it's the best ...
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### How much power could a turbocharger generate?

I can find many figures online for the extra power generated when a turbo is fitted to an engine. However, I can't find any figures on how much energy the turbocharger turbine actually takes out of ...
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### How to fix blocks with attribute tags in AutoCAD which were exploded?

Sometimes I get AutoCAD drawings with attributes outside blocks. Seems that people who don't know how to use attributes try to edit text and blocks but, as they don't know how, they explode those (...
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### Simulating AC using DC

Is it possible to power an AC motor, using alternating positive and negative DC current? I would assume toggling between each at 60hz would work.
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### What are the possible implications of the heating of the structural stonework of Notre-Dame cathedral during the fire?

Yesterday, Notre Dame cathedral caught fire. The roof and the central spire were destroyed and some of the stonework was subjected to high temperatures for an extended period. What are the likely ...
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### Hover Stylus for capacitive touchscreen

Capacitive touchscreens do not rely on touch as the name suggests but rather measure the distortion of the electrostatic field. To my understanding a touchscreen might be able depending on the build ...
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### How to compute core stress in honeycomb structure?

Assume I have a honecomb(sandwich) panel under distributed normal load. Each edge of this panel is simply supported(pinned) as on the picture below: The problem is how to find the core stresses σ-z (...
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### which one is best certification course for WIFI? [on hold]

Is there any certification available for wifi courses, if there which one is best ?
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### How to calculate divided irrigation discharge from a Parshall flume

How do I calculate the discharge from a Parshall flume that flow over a bulkhead (XY) into three partitions (A, B and C) divided 25%/50%/25%. There is no restriction of flow when the pipe gates are ...
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### Why aren't artificial gills used together with oxygen tanks for diving?

Artificial gills aren't used for diving, not because they can't extract oxygen out of water, but because they won't provide enough oxygen for someone to breathe (only arround 1% oxygen in water ...
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### Can a reinforced hose develop an internal restriction due to thermal expansion?

The type of hose involved is the thinnest one on the right in this picture. This hose contains an external rubber layer, a textile reinforcement layer, an inner rubber layer and a nylon lining. The ...
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### abaqus simulatioon

USING ABAQUS SIMULIA 6.13 hysteresis low cycle fatigue of isotropic and kinematic hardening .I use combine parameters but no yielding occurs and hysteresis force disp loop area is zero .I also need ...
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### Energy required to vacuum a cylinder

I'm trying to calculate the energy per unit length the vacuum pumps require to vacuum a cylinder with a diameter D. Which formulas should I use? I used a typical formula for compressors and the ...
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### Why does concentrated shear force on a beam influence the whole beam?

This might be a silly question but can someone explain how this shear force on the right side of the beam causes Qy throught the whole beam? I understand it mathematically but not conceptually so I ...
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### Influence of a diagonal fold on a web + double fold situation

I need to build a steel frame with a steel web in it, as illustrated below. Flanges of the frame will be welded, as well as the web, along its whole perimeter. Would adding a diagonal fold to the web ...
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### Are the nearby airplanes cleared of the sky when launching Falcon Heavy? [migrated]

I was checking Flightradar24 when launch occurred and didn't see any difference. Also, 3 boosters landed back successfully. I assume the sky has to be clear of airplanes to avoid any potential ...
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### Why do 2-stroke engines burn more oil?

Of course, most 2-stroke engines require oil to be mixed with the fuel (I appreciate there are 2-stroke engines that don't require this). Therefore, it makes sense to me that oil will be burnt during ...
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### How to keep lighting “barn doors” open

I have two alum plates (45cm x 20cm x 1mm) that are hinged on the long side with two 30 x 80 hinges (30 x 40 each tang) in the middle, and "L" bracket / 20mm brace at the ends secured with a M4 loc ...
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### How effective will a cooled mattress be for cooling down a baby?

I'm trying to make a cooling device to used in hot areas for cooling down newborns. I'm planning to cool down the mattress to a temperature of 37C, how effective will such a system be to keep the body ...
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### why do errors occur in transmission of packets by network layer when transport layer protocols already make a virtual connection between hosts

As far as I know the duty of transport layer is to make a virtual connection between two hosts that want to share info after that the data is sent to network layer where data is divided into packets ...
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### Gasturbine energy balance

I have a question regarding gasturbine energy balance, the total energy that flows into the gasturbine is given 12 MW and the power needed for the compressor is 4.4 MW and the turbine power is 9.3 MW....
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### Magnetic treatment of hard water to prevent scale and corrosion? How does this work?

I ran across this company at their booth at a Tradeshow (2018). They claim to have a chemical free (and as far as I can tell - a power free) treatment method for hard water to minimize scale and ...