Questions tagged [design]

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Diode laser optics - How to shape the beam of a Diode bar?

I have a 40w, 808nm, CS mount diode bar. I would like to build a something similar to a Rofin Dilas laser diode. How to choose the optics, measure distance, focus the beam into a fiber coupler? I came ...
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1 answer
80 views

Calculating hole size on the side of a pipe

I have a fluid channel through which a fluid with known properties (viscosity, density etc.) flows at a known velocity with a known pressure and temperature and mass flow rate. The external pressure (...
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1 answer
34 views

Frictional wheels without slipping (gear system)

In the figure below it is stated that the friction force should always be greater than the tangential force in order to prevent slipping between two frictional wheels. My question is that if we apply ...
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4 votes
3 answers
177 views

How to multiplex several light sources into one optical path? [closed]

I'd like to design a device that takes 4 channels of light from sets of LEDs and multiplexes them into one optical path, which finally creates a rectangle pattern of light that is approximately 30mm ...
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3 answers
98 views

Are soundproof foam shapes reflective of audio frequencies?

I came across a previous question regarding how soundproof foam absorbs sound: How does foam "absorb" sound? where the answer explains the properties of the foam itself rather than the shape....
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1 vote
1 answer
27 views

Optics viewing angle and distance

Almost all optics like microscope, telescope.. require observer putting their eyes very close to the optics to see. Can the same optics designed so observer can see like viewing TV screen, i.e. from a ...
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3 votes
5 answers
178 views

Electronically controlled fusion reactor

It seems that currently, only two types of fusion reactor styles are being used for large scale testing: the Stellarator and the Tokamak. Both of these and a whole bunch of other designs have been ...
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0 answers
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Can light concentrated through convex lens be "cooled down?"

I've just been assigned this biology design project where I'm being tasked to create a device for maximizing "sunlight exposure" of crops and am unsure of this particular question, for the design of ...
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1 vote
1 answer
108 views

Why does bike trip on the opposite side when turning the handle?

It can be observed on a stationary bike and also on a moving bike that on giving a jerk on the handle the bike leans to the opposite direction in which the jerk is given. Is it due to angular momentum,...
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Slowing the late descent of an atmospheric probe in a gas/ice giant exploration [closed]

I remember the 1995 descent of the Galileo atmospheric module in Jupiter atmosphere. The robust casing made it withstand several dozens of bars of pressure before going out. What measures could be ...
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1 vote
1 answer
248 views

Understanding hyperloop design

I am trying to understand some choices of hyper-loop designers. The effort seems to be focused on trying to bring a near vacuum (space-like) environment to ground level. Why would it not be easier ...
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1 answer
347 views

Measure force produced by air pressure in pipe system with valve

I'm attempting to design a system that uses pressurised air to shoot tennis balls and am struggling to find the right mathematics to calculate the necessary air pressure and volume needed to propel ...
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4 votes
1 answer
672 views

Tuning fork having 2 arms [duplicate]

Why there is 2 arms in the tuning fork? It can have 1 or more than 2 arms. If we think to create more resonance, then we can construct a tuning fork having many arms
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-1 votes
1 answer
2k views

How to find power required for rotating blades given the required shear cutting force [closed]

I want to design a sugar cane bud cutting machine. The rotating blades are connected to the output shaft of a speed reduction box ($30\,{\rm rpm}$). The shear force required for cutting is $1200\,{\rm ...
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0 votes
1 answer
170 views

Can the field of an earth magnet be changed using electricity this way?

Is there any way to coil a wire around a permanent magnetic and apply an electrical current in which a permanent magnet field can be neutralized, increased or reversed? Just like making a simple ...
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1 vote
0 answers
149 views

How does thickness of film affect the quality of the a thin film polarizer?

I have limited optical experience as a biomedical engineering student and am currently trying to spec out a polarizing filter. I understand that there are performance parameters, such as extinction ...
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0 votes
1 answer
2k views

Best cell-phone case design for impact energy absorption?

I've noticed two trends in rugged cell-phone cases: Lots of soft material An inner layer of soft material coupled with an outer layer of hard material. Considering an equal thickness for both ...
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2 votes
1 answer
302 views

In a fusion reactor like Tokamak, how is fuel injected without destroying the fuel injector? [closed]

Plasma temperatures in a tokamak are around 100 million C. Presumably for a power plant that will run for a long period of time, fuel will have to be injected and "burnt" products will have to be ...
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1 answer
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holes in an electronic circuit [closed]

Many times, by looking at electronics circuits I noticed that they have like small holes printed in yhem. The question I want to ask is, what s the purpose of these holes?
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1 vote
0 answers
93 views

Mechanical properties crown cap [closed]

What are the important mechanical properties to look at when designing a crown cork and why? Thank you in advance
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41 votes
4 answers
24k views

Why do most office chairs have 5 wheels?

(Inspired by Why are four legged chairs so common?) I've been wondering for a while... Why do most wheeled office chairs have 5 wheels? My guess would be that while stability vs. simplicity results ...
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262 votes
12 answers
52k views

Why are four-legged chairs so common?

Four-legged chairs are by far the most common form of chair. However, only three legs are necessary to maintain stability whilst sitting on the chair. If the chair were to tilt, then with both a four-...
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1 vote
2 answers
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How to calculate planar window's buckling pressure in vacuum chamber wall

I can't find the formula, I can see some formulas for circular windows are given here [1] (thanks CERN!). For example with a circular (flat/dome?) window, buckling pressure ($p_\text{CL}$) and max ...
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2 votes
0 answers
36 views

Reason for audio speaker diaphragm shape [duplicate]

Why are the diaphragms on audio speakers usually a cone with a dome in the centre? I don't know much about acoustics but my guesses would be: it just empirically sounds better, the design was found ...
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1 vote
0 answers
369 views

How to design a Bitter electromagnet? [closed]

I am designing electromagnets at my home and want to know how can I design electromagnets at home. Bitter electromagnets are really a challenge.
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0 votes
3 answers
174 views

Alternative type energy storage to batteries? [closed]

When designing portable devices it is usually the battery that stores its energy, because it has a high energy density that allows even small batteries to run up to a year, given appropriate circuit ...
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1 vote
1 answer
434 views

Fresnel Rhomb Retarder specifications

In my homework I have a Fresnel rhomb retarder and I am asked to calculate the retardance. I have the refractive index in terms of the wavelength(dispersion equation) and the phase difference incurred ...
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2 votes
2 answers
647 views

The strength and control over the strength of electromagnets, correlation between the strength and weight of the magnets

I am currently working on a project that aims to use the attraction & repulsion between two electromagnets as an alternative to weights, from a physiotherapy and rehabilitation perspective to help ...
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1 vote
0 answers
46 views

What is "full clutching flow" in fluid-dynamics with regards venturi design?

As the title says, what is "full clutching flow" in fluid-dynamics with regards venturi design? I came across this reference a few times and can not find any further info on it, I'm currently ...
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4 votes
2 answers
677 views

From which side should I solder electrical feedthroughs into a vacuum flange?

I work on an experiment that requires electrical connections to a vacuum vessel, which is submerged in liquid helium (LHe). For sending the signals into the vessel, we use a feedthrough flange. I am ...
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1 vote
1 answer
186 views

Design of atomic bomb [closed]

Please see the following photo. (I cannot post it) http://i1163.photobucket.com/albums/q554/startanewww/CIMG4548.jpg Why is atomic bomb in a "fish-like" shape? (I don't know how to describe it) Is it ...
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0 votes
2 answers
4k views

What is the best material and design for building a parabolic dish? [closed]

I'm currently using a homemade metallic spaghetti strainer with a wifi adapter inside it to increase my wifi adapter's signal reception, but would think that a different material, like the aluminum ...
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4 votes
3 answers
1k views

Can anyone estimate what proportion of water remains after I flush a toilet?

Imagine I have a clean toilet with some amount of water in the bowl. When I flush the toilet much of that water will be displaced by the tank's water. I want to work out (or model really) what amount ...
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2 votes
1 answer
222 views

How is/do they plan on having fusion energy collected at the National Ignition Facility?

I was just watching a program on television showing how the method they use at the National Ignition Facility to attempt to achieve fusion is to fire extremely powerful lasers at a small pellet of ...
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3 votes
2 answers
220 views

Proof Human Designs for Fusion Could Work

Are there convincing proofs on paper that fusion is possible the various ways humans are trying to design machines to do it or is the only way absolutely proven to work in theory also the only way ...
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5 votes
4 answers
9k views

Why do aircraft inner wings lose lift when turning?

first question here, so please be gentle! I'm reading an entry-level engineering course book and am currently up to discussion of aircraft design. There's one particular statement that is unclear to ...
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3 votes
3 answers
3k views

Design of a common table fan

A few questions about the design of a common table fan, such as below. Does the round disc (silver in the image) in front of the blades serve any functional purpose? Does the metal casing around the ...
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