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13
votes
3answers
476 views

I have inherited a product with inconsistent designs sharing the same part number. What do I do?

I am now in charge of a product line my company has been shipping for a decade. One of the previous product engineers was... shall we say, less than conscientious about sustainability and proper ...
12
votes
4answers
716 views

Is interference between aircraft an issue for fly-by-wireless technology?

I was reading up on fly-by-wire development, and I saw a short section about fly-by-wireless technology. It seems like a great idea, with the potential to lower costs, weight and complexity. I can see ...
9
votes
2answers
211 views

Why does reducing the amount of emissions control improve the fuel economy of a car?

In addition to power and performance, one of the reasons VW cheated their emissions results was to improve the fuel economy of their cars. Why exactly does this happen? I'm familiar with cars and how ...
9
votes
4answers
14k views

Steel selection for building a trailer

I'm thinking about building another trailer. I've built lots of smaller trailers in the past, but this time I'd like to build myself a small tandem axle gooseneck rated for 7,500 lbs. I am a ...
8
votes
3answers
1k views

Can the structural integrity of bridges be measured in real-time for safety?

As a follow up to this question, I wonder if structural integrity monitoring information can be provided real-time and to a sufficient degree that safety decisions can realistically be made from the ...
7
votes
2answers
5k views

Interpretation of shear flow/shear center of L-profile

I have calculated the shear flows and center of an L shaped profile. I assume they are correctly calculated (I followed the same steps as during the lectures for an I shaped profile). However, I have ...
6
votes
2answers
739 views

Creating smooth shaft resistance

I am trying to emulate the resistance of a hand wheel which moves a table via a series of shafts and chains which turn an acme screw. I am switching to a CNC system that will allow the user to keep ...
6
votes
4answers
201 views

Is radians dimensionless quantity?

Quite often while calculating angular velocity we come across the quantity radians per second. Dimensionally how do i treat radian as?Explain vividly.
6
votes
2answers
199 views

Having three heaters on single PCB

I posted this question on electronics SE, but was suggested that I post it here. I basically having three heaters (serpentine pattern) on a PCB (fiberglass board), as the following image shows: The ...
4
votes
0answers
70 views

Technical Analysis to determine optimal Cellular to transmitter location

At a very high level what are required technical analysis to determine the need to for a new 4G LTE cellular transmitter in US? find find the optimal location for the transmitter in US? Back Story: ...
4
votes
1answer
1k views

Is pin column-beam joint always have less moment, more deflection compared to fixed joint?

I am referring to the answer here: It seems that on a simple structure (The diagrams on the left the images below have fully-fixed connections, while on the right the columns are pinned connections ...
4
votes
2answers
91 views

How were the sequence of bar widths assigned to digits 0-9 for UPC barcodes?

UPC barcodes are comprised of a series of black and white bars. Bars can range in width from 1 to 4 (1 being the thinnest and 4 being the thickest). Each digit, 0 through 9 is encoded using exactly 4 ...
4
votes
3answers
165 views

What causes Rolling Resistance?

I am currently reading “Fundamentals Of Vehicle Dynamics” by Thomas D. Gillespie. The author mentions how the asymmetric pressure distribution across the length of the contact patch of a tire while ...
3
votes
1answer
243 views

Motor Driver board: limited current

I'm having some trouble using a motor driver board. I'm pretty sure its being driven properly since there is ~3V @ the output v.s. none when its off. However it should be supplying ~2A (rectifier ...
3
votes
3answers
785 views

How to design a vacuum climbing robot

I'm trying to design a mobile robot which has to climb over flat 60° inclined wet glass surfaces. I was thinking to use a large vacuum system composed by a large fan connected to a brushless motor. ...
3
votes
1answer
926 views

How to draw isometric view of this shape?

I'm having trouble drawing an isometric view of this shape: I've only just started an engineering course and so far it's involved a lot of drawing which I usually can do but I can't seem to figure ...
3
votes
4answers
187 views

Which components to use for a CO2 gas storage?

I have a CO2 production for my aquariums (currently 2, but the solution should be extenable to - let's say - 5) based on fermentation of bio mass (CO2 is used as fertilizer there) which consist of a ...
3
votes
3answers
527 views

Would a structurally sound pressure cooker be able to withstand an internal vacuum?

Would the body of a normal round pot shaped pressure cooker (built to cook foods at 15 psi) be able to withstand being evacuated down to high-vacuum pressures? Apparently it has been done before: i.e....
3
votes
2answers
1k views

What is the sequence of exams to become a Professional Engineer in California?

I'm in school for electronics engineering. Would someone lay out the high level steps in becoming a professional engineer (PE) in the state of California?
3
votes
3answers
93 views

Determining the transfer function of cruise control given characteristic equations

During my time revising for my control engineering module, i've come across this question The automatic cruise speed control for a vehicle is described by the following equations $\bigl( 1\bigl)$ $...
3
votes
3answers
130 views

Torque and RPM calc

started by designing the gear meshing, and now I need to calculate some parameters to determinate if this meshing works for me. The system considers an electric motor, which technical parameters are: ...
3
votes
2answers
2k views

How does the central lock mechanism in articulated arm (magic arm) works?

does anyone know how does the central lock mechanism in articulated arm (magic arm) works? The magic arm usually used to hold camera, with only 1 knob, it can lock all sides. How?
3
votes
1answer
549 views

How to measure transmit power level from LTE base station?

Can someone tell me what type of equipment is used to measure RF power levels transmitted by a cellular LTE base station? I would like to gain some insight into how the follow data was obtained. ...
3
votes
3answers
6k views

CFM in relation to Static Pressure

My background is more Chemistry and Biology, not Physics, or specifically engineering with fluid dynamics, so bear with me! Also, this is a little long, so I will do my best to make it easy to follow. ...
2
votes
1answer
89 views

What is the engineering term for the gear style articulated arm

You loosen a screw (knob) and then move to the angle you want and tighten. I need to know what the engineering term for this part is. Thank you in advance
2
votes
2answers
666 views

Which US states require a bachelors in Engineering to become licensed?

I am considering moving from abroad to the US, and hoping to obtain an engineering license for employment. I have a bachelors and graduate degree in physics, but I have heard that many states require ...
1
vote
1answer
367 views

MQ3 Alcohol sensor

I have done my project on alcohol detection for drivers, but I don't know the minimum and maximum distances between the alcohol sensor and the driver. What are the maximum and minimum distances?
1
vote
1answer
51 views

Calculating heath exchange for custom boiler

I am playing with the Idea that I should make a my own heath exchanger to generate warm water. But as a hobbyist I would like to calculate the potential of my design and here is the question for me, ...
1
vote
2answers
1k views

Torque required to launch a tennis ball

I am trying to find out if the 12 V DC electric motors that I have are powerful enough to launch a 100 g tennis ball 30 m away. The tennis ball is put down a pipe and ends up wedged in ...
1
vote
2answers
76 views

Wouldn't it be most effective to insulate a house with just an air space?

It is my understanding that of all three states of matter, gases have the lowest thermal conductivity. If this is the case, why are solid materials, such as fiberglass and polyurethane, used for ...
1
vote
1answer
267 views

What ramping constraints for gas plant - CCGT, combustion and steam turbine?

I am using the publication Current and Prospective Costs of Electricity Generation until 2050 to source ramping constraints for an economic model of three different gas power plants - CCGT, combustion ...
0
votes
1answer
75 views

Installing satellite dish to point to local zenith

After receiving help on my previous post (Stopping/reducing wobbliness in threaded rod), I've decided to come back and ask another question: how can I actually hold the satellite dish into place? I ...
0
votes
1answer
468 views

Tau max value in torsion calculation [duplicate]

I am going to try and ask this question again. In this formula to calculate shear stress in a solid shaft: τ = T r / J If I want to solve for the radius; I should use the modulus of rigidity ...
0
votes
2answers
465 views

Deflection of parallel rods with force at an angle

As in the picture below, there is a static force $A$ being applied at 45 degrees to a rigid rod attached to a rigid plate. The plate is supported by two rods of length $B$ and diameter $D$, each of ...
0
votes
2answers
1k views

angle of twist of gear relative to another gear

why the torque is negative in this case ? the question ask for determine the angle of twist of gear C with respect to B . We have to 'fix' the B , and determine the twist of C ? So , imagine that we ...
0
votes
2answers
60 views

producing vibration motion of a plate (1cmx2cm) placed in water

In order to conduct a study, I need to place a rectangular plate freely placed (1 cm by 2cm) inside water and control it from outside (better wireless). I need to give oscillatory motion with specific ...
0
votes
1answer
44 views

Are stator magnets in brushed DC motors radially magnetised?

In an electric motor like this one, are the stator magnets radially magnetised, as in, each of the two magnets has opposite poles on the inside and outside diameter?
0
votes
1answer
447 views

Dc motors for controlling wheels of a wheelchair

I am doing a project on controlling wheels of a wheelchair. The diameter of the wheel is about 25-30 inches, the weight which the wheelchair is supposed to carry is upto 80 Kgs and it should run at a ...
-2
votes
1answer
43 views

what should be the size of gate? [closed]

what should be the size of gate? if street 8 ft according to house map Car entrance gate 11 ft can corolla grande car enter into the gate easily with some moves?
53
votes
3answers
35k views

Why is kVA not the same as kW?

I thought my electric car charging unit uses 6.6 kW of power. However, I found the label and it actually says 6.6 kVA. When I saw this I thought something along the lines of... Well, $ P=...
52
votes
9answers
19k views

Why do cars have mirrors for rear view rather than cameras?

Despite having so much technological advancement, I wonder why cars still uses mirrors (right and left side of the driver) for the rear view. These mirrors can be easily replaced by cameras and ...
21
votes
8answers
2k views

How do engineers really use numerical simulation?

Disclaimer I'm an applied mathematician by training, not an engineer. My work research primarily focuses on creating new "methods" to solve different PDE's related to solid deformation (elasticity) ...
6
votes
1answer
5k views

Involute gear curve when root diameter falls below base diameter

The answer to a question on involute gear curve calculations shows how the gear tooth curve proceeds as an involute calculation from the base diameter. If the pitch diameter is D = m.N where N is the ...
42
votes
9answers
7k views

Is it possible for a bicycle chainwheel to have a fractional number of teeth?

Background In the world of bicycle motocross, also known as BMX racing, gearing is a hotly-debated topic. Since the bikes are all single-speed, gear ratio is a fixed number defined as ...
13
votes
2answers
5k views

Quantifying inertia on the electricity grid

A lot of discussion about the modernisation of electricity systems is about "inertia". This is usually a qualitative discussion about how turbines (in hydro, coal & gas plants) with lots of ...
43
votes
9answers
6k views

My customer wants to use my products to do something unsafe. What is my ethical obligation?

We sell products that attach to a motor drive's DC bus. We also formerly sold diode kits that let you hook one product up to multiple drives. We stopped selling those diode kits because they were ...
32
votes
4answers
8k views

Why dig out and then fill in before building a large structure?

I work in the middle of London, in an area full of large office blocks. Across the road from my office they have started construction of a large building (10 stories plus). Over the last few weeks, ...
22
votes
3answers
1k views

How to know whether the flow is supersonic in a nozzle?

For a project I had built a convergent divergent nozzle designed for Mach number = 3. In that project, I could know the flow has gone supersonic by seeing the manometer fixed between the throat and ...
13
votes
3answers
4k views

What happens when you put the wrong type of fuel in an internal combustion engine?

What happens to the working of petrol engine when it is emptied and filled with diesel or to a diesel engine emptied and filled with petrol? Will the engine be able to operate and, if not, why not?
12
votes
3answers
4k views

Can a magnetic lock be negated or overcome by a stronger electromagnet?

Magnetic locks seem to be fairly common on the doors of modern buildings, but I question their reliability when compared to a traditional, mechanical lock. I realize that the strength that it would ...

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