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12 votes
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Why does the stress-strain curve decrease?

For the explanation of the loss of stress from E to F, I'll refer you to my answer to another question. Basically, the drop in stress seen in the diagram is a consequence of the fact that we use ...
Wasabi's user avatar
  • 13.1k
9 votes

Why does the stress-strain curve decrease?

To add to the other answers: interstitial solutes effectively "lock" dislocations in BCC metals (such as with carbon and nitrogen dissolved in iron), by forming what are called Cottrell atmospheres (...
do-the-thing-please's user avatar
6 votes

What can be the mechanism used in devising a machine that can arrange the dishes properly to make the cleaning faster in the messes/hotels

Some of this depends on how tough the dishes are. While taking a lot of room, I can see possibilitiles in a conveyer sorter. Concept one: Dishes are dumped onto a conveyer that is on a sideways slant....
Sherwood Botsford's user avatar
4 votes

Replace Hydrogen in an air cylinder

Structurally the pressure is independent from the nature of the gas. So, it shouldn't matter if its $N_2$ or $O_2$. Special care should be taken with corrosive gases, but usually that means the ...
NMech's user avatar
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3 votes
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Talking in terms of 6 sigma, why 4 ppm would be very costlier than 1 ppm (part per milion)?

If we talk about quality and 6-sigma (which roughly means 1 ppm defects), the 1 ppm refers to test escapes, not test rejects. Even if a part only costs \$1, if testing fails to catch a bad part and ...
The Photon's user avatar
3 votes
Accepted

Manufacturing screw thread onto lid

These threads are rolled. The blank is automatically fed to sit around a central wheel which has the form of the thread. An external arm with the opposing half of the form then lowers to apply ...
Jonathan R Swift's user avatar
3 votes

3D construction

There are several pages about building kids trailer: New EU Standard EN 15918:2011 for Bicycle Trailers Bicycle trailer There is mentioned EU standard: A voluntary European standard (EN 15918) ...
Katarina's user avatar
  • 314
3 votes
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silicone injection molding - making a flexible ring

If you are using RTV silicone of the type used for prosthetics and animatronics then you can get a variety of grades with different mechanical properties, commonly rated by Shore Hardness. You can ...
Chris Johns's user avatar
  • 15.2k
3 votes

FE Exam practice: "How many years until you're a millionaire?"

I'm not doing notation for this, it's simple algebra. X = 1,000,000 = 5000 / .1 * ((1.1)^n - 1) 1,000,000 = 50,000(1.1)^n - 50,000 1,050,000 = 50,000(1.1^n) divide both sides by 50,000 21 = 1.1^n etc.
Tiger Guy's user avatar
  • 6,901
2 votes

Why does the stress-strain curve decrease?

Further adding to Wasabi answer, The yield point phenomenon occurs due to the segregation of impurity solute atoms(C and/ or N in Fe) around dislocations so as to reduce the strain energy associated ...
preet dhunna's user avatar
2 votes

Folded/bent sheet steel design

Many CAD packages do have tools for sheet metal design which can plan folds, tabs etc for manufacturing. However you do need to have at least some understanding of the practicalities of the process ...
Chris Johns's user avatar
  • 15.2k
2 votes
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What are SCADA Boxes?

The plant I used to work at had a Supervisory Control And Data Acquisition (SCADA). They had all kinds of transducers measuring everything in sight and we could sit in the control room and check on ...
user1683793's user avatar
  • 1,020
2 votes
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Why isn't air added to the primary reformer in ammonia production?

This report from Rice University covers design and economics of synthesis gas reformers. Reaction 1: $CH_4+H_2O<->CO+3H_2$ (Steam reforming) Reaction 2: $CO+H_2O<->CO_2+H_2$ (Water gas ...
morristtu's user avatar
  • 538
2 votes
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How to bend copper heat pipes?

Copper is notoriouos for hardening and breaking under bending or hammering it, or working it any other way. To keep it soft and flexible, you have to anneal it often while working on it. It also bends ...
Bart's user avatar
  • 1,184
2 votes

Which design to maximize friction for a device standing on concrete?

If you have a rubber that you believe has the best coefficient of friction possible then it wont matter too much how it is shaped unless you need to deal with water or mud like a car tire. The best ...
Brice Edward Furr's user avatar
2 votes
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Analizing Vibrations Influence on Dynamic Weighing

So, look at the time history that you added in edit 3. Notice how it is never ever ever below 1. That's very telling. Let us assume that you have a MEMS accelerometer is able to read down to 0 ...
Daniel K's user avatar
  • 2,646
2 votes

Modelling reactor jacket with or without insulation, how to proceed?

Full Analysis Perfectly Insulated System The best case is to analyze this system in both the time and position domains. The time domain considers the variation of the reactor temperature $T_r(t)$ ...
Jeffrey J Weimer's user avatar
2 votes

In the 1980s, did radio reporters actually carry around a clunky antenna contraption on their backs to communicate with their radio station's HQs?

On the BBC in London, in the 1980s, if a BBC radio station had to report on a live sports fixture, and it was not a live broadcast of the whole game, just a half-time report, or full-time report, the ...
Ed999's user avatar
  • 121
2 votes
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What are the charge/power connector of restaurant order pagers / buzzers called?

The following pins appear to be pogo pins or spring loaded pins Below are example of pogo pins The following appear to be swage mount connectors Here is an example Reference: Mill-max How to pair ...
Mahendra Gunawardena's user avatar
2 votes

PID or AI or other approaches to this thermal control problem?

IMHO, you don't really need AI. PID (or even PI) would be sufficient in this problem. Arguably, you might need to add a cascade controllers (or two), but it should be sufficient. Although AI is ...
NMech's user avatar
  • 24.4k
2 votes
Accepted

How can the function of a separation funnel be accomplished industrially?

I would use A tall narrow storage tank to separate layers into long cylinders one on top of the other with several valves at appropriate heights. Wait for them to settle Insert a densitometer or ...
kamran's user avatar
  • 22.4k
1 vote

Talking in terms of 6 sigma, why 4 ppm would be very costlier than 1 ppm (part per milion)?

1ppm is 4 times better than 4ppm. If 4ppm of parts are indicated it means that 0.0004% of these parts have to be discarded. It is always better to have a lower number of discarded parts which means ...
André Rodriguez's user avatar
1 vote

Squirrel-cage air blower efficiency

These are called centrifugal fans and are typically from 60 to 90% efficient. They are tested and rated by Air Movement and Control Association, AMCA. They are usually tested under standard air ...
kamran's user avatar
  • 22.4k
1 vote
Accepted

Which design to maximize friction for a device standing on concrete?

I would use three(triangulated) very sharp tip toes, stainless steel conical points so that they dig into the asphalt a little bit with a little pressure from the installer :-) I don't know if they ...
William Hird's user avatar
1 vote

Coating brass components cheaply

a silver coating on brass is usually nickel electroplate. does your part have to be brass? if it can be made of plastic instead, a shiny coating of metal can be quickly and cheaply applied to it in ...
niels nielsen's user avatar
1 vote

AirFlow Measurement

To measure an airflow you can measure the pressure drop across a section or before and after a bend. That pressure difference can then be calculated into the flow rate.
Solar Mike's user avatar
  • 15.8k
1 vote

Recommended compressed air source and location for separate air compression system

From skimming a (sadly german language) "blower bible", it seems that high pressure radial blowers are mostly used in the pressure range you need. Axial blowers appear to deliver a too low pressure, a ...
mart's user avatar
  • 4,781
1 vote

Metering pump that is either computer compatible or microcontroller compatible?

I am pretty sure most dosing/metering pump manufacturers provide some degree of what you are asking for. I know that we have used Prominent before and they make metering pumps that can be controlled ...
Secundus's user avatar
  • 571
1 vote

Is it possible to make very large diamonds using a pressure vessel at several GigaPascal pressure?

Such a pressure vessel is not technically achievable with current technology. See this question. There are two main methods of making synthetic diamonds. HPHT (High pressure, high temperature), ...
atom44's user avatar
  • 2,641

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