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14
votes
3answers
5k views

Can I use a ultrasound sensor to measure water level?

If I use an ultrasonic sensor will it detect the water level? I was thinking about a product to read water level on water boxes (common in Brazil). I researched about instrumentation for this ...
18
votes
3answers
55k views

Calculating pitch, yaw, and roll from mag, acc, and gyro data

I have an Arduino board with a 9 degree of freedom sensor, from which I must determine the pitch, yaw, and roll of the board. Here is an example of one set of data from the 9-DOF sensor: ...
15
votes
3answers
25k views

Effective ways to drive a single shaft with multiple motors?

To head off the "why not use a bigger motor" question, I'm a high school mentor for an FTC (First Tech Challenge) robotics team, with a bit of a soft mechanical / hardware background. They're ...
16
votes
1answer
52k views

Understanding required torque for a motor lifting a weight

This is a continuation of me trying to understand torque and stepper motors in my other question. I'm trying to understand the torque a motor would be required to generate to lift a small weight, and ...
11
votes
3answers
1k views

Thermoelectric Technology to Harvest Energy from Internal Combustions Engines

Background: In an automobile, only 1/3 of the potential energy in the fuel is converted into mechanical energy and significant portion of the energy is lost as heat. There have been previous ...
6
votes
3answers
6k views

What is Radial and Thickness Mode Vibration in a Piezo Electric Ceramic Disc Transducer?

I am trying to use a Piezo Electric Ceramic Disc Transducer for ultrasonic sensing measurements for fluid levels. A Piezo Ceramic Disc with a Resonant frequency of 215 KHz or 1 MHz is under ...
3
votes
1answer
2k views

Why is the point of failure load lower than the peak load? [closed]

In a tensile test the peak load was 69kN, but the point of failure load was 60kN. Why is it lower?
2
votes
2answers
176 views

Cooling Hot Nitrogen with an aluminum block

I'm designing a cooling system to cool nitrogen gas stream at 300°C with a mass flow rate of 15.6 g/s moving through an undulating channel in a cylindrical aluminum ring block with external fins. How ...
8
votes
2answers
1k views

Harvesting thermoelectric energy from computer graphics cards

During CES2015 a well know Graphic Processor Unit (GPU) manufacturer introduced a new GPU. These GPUs need complex thermal management to keep the processor cool. Most GPU accelerator card ...
6
votes
3answers
244 views

How can the vendor be approved/disapproved based on validation test data?

The power requirement for a sub system is 5V +/- 10% @ 1A of current. A RFQ was issued and a prospect vendor was selected. A first article of inspection (FAIR) has been submitted which includes 15 ...
4
votes
2answers
151 views

How can I arrange my ECO system to enforce the principle of least privilege?

Right now, changes to BOMs are executed through verbal or email instructions to an employee who serves as BOM gatekeeper. This means paper trails are almost non-existent. Who changed what and why is ...
4
votes
3answers
687 views

System curve for use in determining pump operating point

What is meant by a "system curve" that is used to determine the operating point of a pump. I know what a "pump curve" is, but I often hear about a "system curve" being generated so that the pump ...
29
votes
12answers
32k views

What are the pros and cons of a traffic circle versus a traffic light intersection?

The debate of traffic circles (also called roundabouts or rotaries) versus traffic light intersections has been in progress for a while. Those in favor of traffic circles say that, among other things, ...
14
votes
2answers
2k views

How should I position two shelf supports for the best distribution of load?

I'd like to mount a shelf on the wall. I have two shelf supports to do so, like this: Relative to the shelf, where do I place the (blue) supports to achieve the best distribution of load?
19
votes
2answers
2k views

What are the major differences between Engineering degrees and Engineering Technology degrees in terms of employability?

What difference in education occurs between two graduates, one with an Engineering Technology degree (be it Civil, Mechanical, Electrical...) and the other with the equivalent Engineering degree "...
18
votes
2answers
27k views

How does width and thickness affect the stiffness of steel plate?

I have a 2 mm thick steel plate which is 300 mm long and 30 mm wide, supported at either end. It supports a weight-bearing wheel that can roll along the plate. It currently supports the maximum weight ...
7
votes
3answers
6k views

Can I reduce the column moment due to beam, by setting the beam end to pin?

I have a structure, which contains only frame elements ( beam and column). From what I know, if I apply point load at the columns on both left and right hand side,and if the beam-column joint is ...
11
votes
2answers
7k views

Why do we even use engineering stress?

Surprisingly this hasn't been asked before, so I must be missing something simple. We use engineering stress and engineering strain in this eq. Stress = (Young's modulus) × (strain). This eq. is ...
10
votes
3answers
1k views

Why were engineers negligent in the 1981 Hyatt Regency walkway collapse?

I was recently reading up on the 1981 Hyatt Regency walkway collapse. It was a tragic loss of life and haunts many to this day. The linked article does a better job of summarizing things, but here's ...
7
votes
5answers
1k views

How to identify low quality electronic components early?

Our component sourcing organization purchases large amount of electronic components from suppliers. I believe this is through a bid process. Engineering provides the sourcing organization ...
6
votes
1answer
2k views

Why use steam in the rankine cycle?

In the rankine cycle, water is first pressurized and then heated to produce steam before it is used to turn a turbine. As far as i know, this is what is considered the best way to extract mechanical ...
5
votes
1answer
3k views

How do I calculate an estimate for the properties of a composite material?

For a given laminate made of composite material (composed of fibers oriented in a carefully designed sequence coated and embedded in a matrix material), where can I begin estimating the stiffness and/...
5
votes
2answers
3k views

Why the design of continuous beam is always more economical than beam with supports?

Assuming that I have a beam that spans across a few supports. I can design the beam as a continuous beam (a beam that is loaded and has more than two supports), or individual beams that each encompass ...
2
votes
1answer
907 views

How to determine if an engineering process is stable and capable?

Mostly interested in understanding how engineers determine if an engineering process is stable and capable, particular in design for manufacturing (DFM) frame work for components. Some example ...
0
votes
1answer
68 views

Engineering Drawing-Projection of intersection curve of two standing cones

I have this projection of two intersecting cones, and I am asked to draw the intersection curve of the two cones on the projection. What is the right way to do it?
27
votes
10answers
6k views

How to quantify martial arts strikes?

Subtitled: Ah, strong am I with the Force, but how do I measure it? With all due apologies for paraphrasing Yoda, I am trying to measure a force. Fortunately, it's an easier force to measure than ...
10
votes
3answers
34k views

How to determine the characteristic length in reynolds number calculations in general?

I understand that the reynolds number is given by the expression $Re=\frac{\rho v L}{\mu}$, where $\rho$ is the density, $v$ is the fluid velocity and $\mu$ is the dynamic viscosity. For any given ...
23
votes
4answers
2k views

How are increasingly accurate machines made?

Making extremely accurate machines seems like a chicken and egg problem. How do you make one if you don't already have one? For example, how was the first indexing head made without an indexing head ...
22
votes
8answers
9k views

Why use steam instead of just hot air?

As I understand, a steam machine needs a pressurised gas to work. This can be compressed air but it used to be steam. Energy was provided to the steam engine by heating up water. I don't understand ...
32
votes
2answers
12k views

What is the purpose of these diversions in a natural gas line?

The campus where I work has a long covered walkway (~.5 mile) which has several labeled pipes running under the roof (chilled water, fuel oil, air...). All of the pipes run dead straight except for ...
15
votes
5answers
4k views

When do I need to consult a professional engineer during a home renovation?

I am a homeowner who likes to save money by performing DIY work. When possible, I prefer to serve as my own general contractor to reduce the cost of a project. However, when I talk with professionals ...
12
votes
6answers
346 views

In Engineering fields, how often do you find yourself being asked to be a “salesperson”, and what is your reaction? [closed]

I have recently been told that my "salesmanship" is lacking when it comes to getting my ideas implemented. I receive the feedback that my ideas are sound and the data to implement is compelling, and ...
10
votes
5answers
16k views

How to calculate lever force when lever has uniformed distributed load?

We have a simple class 1 lever: $$\begin {array}{c} \text {5,000 kg} \\ \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \downarrow \, \...
8
votes
1answer
2k views

Why don't we use principal maximum stresses when designing a structural element?

Consider a concrete column is under compression from top loading and also carries some shear stresses. If take a plane 2d element in the column with these stresses and rotate it to the point it gives ...
7
votes
2answers
3k views

How Can I Determine Multiple Discharges from a Pipe Network? (Knowing the Inlet Conditions)

I have little/no experience with pipe networks and have been searching for a methodology to calculate the discharge from multiple outlets of an oil pipe network with a single inlet. As far as i can ...
18
votes
5answers
2k views

How are passive houses made in very hot regions (like Saudi Arabia)?

I think, here is the main problem the difference between the internal and the external temperature. For example, in Saudi Arabia, in 50 C, a passive house needed probably much sophisticated planning ...
14
votes
2answers
513 views

Why are lasers used for concentrated light applications instead of incoherent light sources?

Some laser applications consist simply of concentrating light into a small spot. Two example applications are laser welding and cutting. In these cases a CO2 laser is often used which needs a ...
9
votes
3answers
2k views

How in Rankine cycle the turbine generates more power than the pump takes?

In Rankine cycle there's the boiler where water gets boiled into overheated steam. On input there's a pump that delivers more water, and on output there's a turbine that picks up the energy of the ...
9
votes
9answers
4k views

How can “mpg” be high under low engine load?

Let's say a car at 60 mph requires roughly 20 hp to maintain its speed (i.e., to overcome rolling resistance and drag). If this car makes 240 hp and gets about 34 mpg (not too unrealistic), how is it ...
5
votes
1answer
584 views

How to derive Equivalent Static Load for irregular structure modeled with FEM?

Building codes such as the Uniform Building Code (UBC) or International Building Code (IBC) require the determination of Equivalent Static Lateral Forces in order to compute $P-\Delta$ effect and to ...
8
votes
5answers
631 views

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

Biogas slurry often contains sand and grit and organic matter that eventually sediments. Clearing thetank from sedimentation is expensive (plant downtime, additional equipment) and dangerous. So it ...
7
votes
4answers
2k views

What are the common failure points of waterproof cases?

I am making a waterproof case for my Galaxy S5 and/or my Raspberry Pi. I plan to make the main body from (or at least decorate it with) wood, though I can use other, stronger materials where needed. ...
4
votes
3answers
4k views

Why does a continuous beam have less deflection than a pair of simply supported beams?

Inspired by this question, and also this answer to a separate question. I have two beam models, one with two independent spans (a full hinge), another is a continuous beam over both spans (only ...
4
votes
2answers
122 views

Formula to describe flow over thin weir

I have thin weir, really just a sheet of metal with a smooth and straight upper edge. I want to know how much water will flow over this weir, when the water level on the higher side is a few cm above ...
3
votes
2answers
527 views

How this radio knob converting a rotation into a straight-linear motion?

Few months ago I opened the boards of an old, scrap radio-cum-tape-recorder (Philips DR183); whose tuning knob (that adjusts the gang); was very peculiar. ( * I did not found its datasheet on web) ...
3
votes
1answer
2k views

How to calculate if a motor is capable for a load?

I am trying to figure out if a motor I have is capable of spinning a wheel. Here is all of the information I have: MOTOR: 190 g.cm min. WHEEL: 26 cm diameter, weighs about 59 grams I imagine that I ...
2
votes
6answers
3k views

How to reduce Engineering Bill of Material Cost for electronics products?

What is an effective method to re-engineer a current product to reduce engineering bill of material (EBOM) cost? This is a continues improvement project for a current product in electronics space. ...
1
vote
1answer
68 views

can we run rotary compressor of Air conditioner with different frequency level?

I am working on split type AC compressor. I actually want to know, if i changed the frequency of the compressor to run on different power level, will it affect the life of the compressor. My actual ...
13
votes
3answers
461 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
2answers
1k views

What is the process of transferring an engineering license from the United States to Germany?

The United States have different rules about exactly how one obtains an engineering license, but the general process is the FE exam, a few years of work, and the PE exam. Suppose one then wishes to ...

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