16 votes
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Can we change steel properties by application of magnetic field while quenching?

This will at least depend on the: Rate of Cooling Magnetic field strength Exact composition The magnetic field will alter the microstructure as you can read in, for example, Yudong Zhang, Nathalie ...
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  • 1,618
11 votes
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Block diagram vs flow chart?

Use Google's define:<item to look up> feature. block diagram noun: block diagram; plural noun: block diagrams a diagram showing in schematic form the ...
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  • 8,469
9 votes

What is the correct pipe size for a 2inch pipe?

As of the 2013 edition of ASME B16.5, the scope section explains: This Standard states values in both SI (Metric) and U.S. Customary units. As an exception, diameter of bolts and flange bolt ...
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  • 4,501
7 votes
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Does every engineering design needs to have a complete theoretical backing or may experimental data suffice?

Are any designs based solely on data from trial and error used in critical mainstream engineering? Usually not. And the reason is that trial and error is expensive and time consuming. As engineers, ...
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  • 2,511
6 votes

In the context of a known disturbance $d(t)$ in a control loop, what is the $\Delta t$ at which the control loop has to be executed?

The choice of time step sets the bandwidth of the control loop. The highest unity gain frequency (UGF) you can hope to achieve in the closed loop is the Nyquist frequency $$ f_N=\frac12 f_s=\frac{1}{...
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6 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

Buy a depth finder! As @SF pointed out, you can use an ultrasonic device to measure the depth of the water. These devices work by sending out an acoustic impulse and recording the return signals. ...
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6 votes
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What is the correct pipe size for a 2inch pipe?

I would guess that the discrepancy is down to rounding fractional inch sizes to decimal inches ie 2.38 is not exactly 2 3/8" Note that 2.375 (two and three quarter eighth inches) is 60.325mm
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5 votes
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How do temperature and pressure influence the rate of evaporation of water in a closed vessel?

$\frac{1}{22.4}\frac{\mathrm{mol}}{\mathrm{L}}$ is only valid for standard conditions. Use the ideal gas law to calculate the concentration for your conditions. $s \equiv$ standard conditions $2 \...
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  • 1,704
5 votes
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How to prevent static buildup in an electric burr mill coffee grinder?

What is the cause of this static charge in the grinding process? My thought is that the coffee grinder is essentially acting like a Van de Graaff generator. Since the coffee maker likely has a ...
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  • 3,587
4 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

If you want this automated, probably Rachet's solution is better; for a more low-tech approach for periodic manual testing, a wide, flat weight on a rope will work; lower it below water surface, let ...
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  • 6,133
4 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

You can put a rod with a blades on the bottom rotate it along the bottom. when the resistance is high then the sediment has reached above the blades and it is time to clean the tank.
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4 votes
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What's the difference between annealing, curing and sintering?

Annealing is a heat-treatment process for stress-relief of a material. Annealing facilitates reduction of internal stresses and total elastic energy stored in inter-atomic bonds within a treated ...
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  • 3,981
4 votes
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Real world applications where one would use a force function in PLC programming?

A "force" in a PLC is the act of forcing a memory bit on or off from the PLC programming software. It is used exclusively for testing. Forcing a bit on or off over-rides all other PLC logic. You can ...
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  • 7,489
3 votes
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Mass Transfer from an Oxygen Bubble

Your approach is wrong because the left hand side represents the derivative of the composition of two time dependent functions. You completely ignored that fact and started cancelling terms. I try to ...
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  • 1,704
3 votes

What's the difference between annealing, curing and sintering?

Knowing the context here might be useful. These terms have nothing to do with each other. Annealing is warming a metal, usually steel, to give it a soft, easy shaped type of crystalline structure. ...
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  • 1,615
3 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

It sounds like the problematic solids level is/can be known ahead of time. Assuming this is the case, you could install a vibratory apparatus at the bottom of the tank, and some sort of acoustic ...
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3 votes

What is a PD pump that I can use as an immersion pump for a slurry?

I've worked quite a bit with vacuum pumps in the past and they certainly could get your slurry out of the tank however a complete rig can run in the $10,000 range. Another less expensive option is ...
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3 votes

Boiling Point, Pressure and Distillation

In ambient pressure, ethane boiling point is -89 °C; ethylene boiling point is -103.7 °C. Water, to act as efficient coolant needs to be liquid, so above 0 °C. You're not going to condense ethane ...
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  • 6,133
3 votes

How do you get a closed vessel to >90,000 psi internal pressure

Contact an engineering firm with experience designing and building such systems and vessels to code. Otherwise, you're just building a bomb.
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  • 2,135
3 votes

Valve first,then heat exchanger OR heat exchanger first then valve

I think the key information is that the liquid is saturated. This means any reduction in pressure will lead to partial vaporization and two phase flow. For heat tranfer best overall heat transfer ...
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3 votes
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Modelling gas desorption from a still solution (e.g. a beer)

In perfectly stagnate gas systems, transport of a component through a gas collapses to diffusion of the component through the gas. In this case, $k_L a \propto (D / \delta)^n$ where $D$ is diffusion ...
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3 votes

What is the fouling effect (in rate, foulant thickness) of sand inside tube side of a shell and tube heat exchanger?

There is quite a bit to unpack here, so I may need to deconstruct your question a bit. Your question is surrounding the fouling rate of a Shell & Tube (S&T) heat exchanger which I will get to, ...
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2 votes

Sizing a pressure safety valve for two-phase flow

While designing a relief the valve flow rate is the deciding variable. To calculate its value in two phase flow different models can be used like HEM, drift flux, separated flow, etc. For this ...
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2 votes

Baffle vs Bottom Temperature Measurement/Control

When there is a change of temperature of the reactor contents, which sensor detects the change first? The quicker the effects of a change can be detected, the more responsive the control system and (...
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2 votes

Recommended models for mineral liberation in crushers

You might want to look up the the "Bond Work Index". It's an empirical method for understanding the energy required to achieve certain amounts of comminution (think P80) for a given method and mineral....
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  • 131
2 votes
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Steam sterilization of whey in a bioreactor

It all depends on the sterilization level you want to achieve. As you say, you would need to know the death kinetics parameters, or equivalently the log-decimal reduction time (D) and how it changes ...
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2 votes

Gas cleaning in activated carbon filters - How much moisture is needed and why?

In terms of bed capacity, dry gas—0% moisture, or as close as you can get—is generally optimal. Section 12.4 of Air Pollution Control (Cooper & Alley, 4th ed.) characterizes the impact of several ...
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  • 3,211
2 votes
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Problem with process controls/simulink?

Time Constant and systems A second order LTI system in Laplace domain: $\hspace{2.5em}$ $H(s) = \frac{{\omega_{n}}^{2}}{s^{2}+\zeta\omega s+{\omega_{n}}^{2}}$ The solution is: $\hspace{2.5em}$ $h(t) = ...
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2 votes

How can I measure the thickness of a sedimentation layer in a closed tank?

For a low tech and somewhat primitive method, given a metal tank with access to the bottom you could simply tap on the outside of the tank with a metal or other hard object (not hard enough to dent or ...
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2 votes
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Derivation of Overall Mass Transfer Coefficient

Regarding $k_p$: So, you've got $N_1$ a flux in $mol/ s \cdot m^2 $ and a partial pressures $p_i$ in $Pa$. $k_p$ has got to connect those, and make the units work out. Exactly what $k_p$ is depends ...
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