Engineering

Hi, I've heard that under-display fingerprint sensors require OLED panels. Why is this?

What do you think about hypothetical supercapacitor in which charge would be stored in electron-hole double layer created between a conductor (which could be graphene or activated carbon) and a hole conductor (which could be a P-type semiconductor)? Difference in work function suppose to prevent electrons migrate inside a P-type semiconductor and recombine with the holes. A hole conductor could serve as a separator between electrodes. Were there such ideas in the past? What farther could prevent recombination? Do you think such capacitor going to leak charge?

Hi Guys, I am working on a project that requires the load ratings of polyurethane covered bearings (over-molded). Loading these types of bearings could be a very dynamic situation and take into account temperature, rpm, load, etc. My question is, do you think this can be derived using a formula that takes into account the thickness & width of the material, the compression modulus of the specific urethane being used, the load, and deflection to determine an appropriate load rating? Or should this only be determined through physical testing? Even the "failure point" doesn't seem very clear. Obviously the urethane is the weak link so the bearing load rating wil…

I have an AVS that is not working. It shows input voltage been displaced on the voltmeter. All the LED not coming up. Output voltage not coming up too. What can be the probably the root cause? And solution.

What the title says. im not talking about magnetic induction but an actual converter like a funnel. One end sucks in magnetic field and the other end spits out usable electricity? I asked this question because, since magnetism and electricity “come together”, meaning that magnetic fields must/should contain electricity. I visualize it as magnetism cages electricity in a spiral/helix fashion, to convert that to usable elec. maybe reverse it so that the elec cages the magnetism. (Random) Do u guys know what the mag fields really are? What im saying is instead of a field going from north to south, north has an entirely separate field in a clockwise t…

Majoring in engineering's kind of a damned-if-you-do, damned-if-you-don't these days. If you major in engineering, you're told there's an excess of engineers anyway and it's on you if you don't find a job with it. If you DON'T major in engineering in, you're trash-talked on the basis of whatever else you studied supposedly being worthless. What I'm wondering is, how can there be too many engineers in the first place? Surely all those other jobs could eventually be done by robots, and the more engineers we have, the sooner we'll get there. Why isn't the government hiring the "excess" engineers to design robots to do all the other jobs?

Do AC motors/generators make frequencies since it alternates, it should be an oscillation or a frequency? I'm curious if Tesla used AC generators/motors to do high frequency stuff and is that frequency similar to sound frequency or even the frequency of everything?

Is it possible to store propane in some kind of adsorbent to make its use completely safe? In my understanding this is a safety issues which prevent wide use of propane as a motor fuel? Will it reduce its volumetric energy density? How long time will it take to soak adsorbant with propane?

One of the zinc-air rechargeable battery largest problems is water based alkalic or acidic electrolyte. However promising organic, polymeric and ionic liquid electrolytes provide thousands of times smaller currents than water based ones for now. What is exactly problem there? https://pubs.rsc.org/en/content/articlehtml/2014/cs/c4cs00015c Which type of rechargeable metal-air battery could be more promising than zinc-air?

That must be function. You must take so strong coils as you can on a body that is permability for magnetic fields and then push the plasma in one direction. Formation of a magnetic field by stretching a plasma volume. https://books.google.de/books?id=wkEpBAAAQBAJ&pg=PA61&lpg=PA61&dq=plasma+magnetfeld+verstärken&source=bl&ots=6T0VrWl7Uq&sig=BPFZk0n8lDnI0d-_ysoLiGIBja4&hl=de&sa=X&ei=6Ys_VOSiNIn6PL-JgYgB&ved=0CFEQ6AEwBg#v=onepage&q=plasma magnetfeld verstärken&f=false the incompressible plasma increases the field strength .... Since the volume must then remain the same, the total magnetic energy increase…

With force you can make things magnetic or entmagnetize them. You can make things magnetic with a hammer, when you make it correct. Here is an example.... https://www.wikihow.com/Make-a-Compass In this link you can magnetize a needle with force. Look at this.... Its an experiment from me. Then think about rotating discs, that rotates so strong that they wohld be magnetic. You have then a magnetic field that moves. And with magnetic fields that are in move you can ionize air and make a plasma. Look at this... And then the simplest thing is you make an object that shovels with a strong plasma, at an example with …

My dear visionary and megalomaniac human fellows, you've probably heard about Solar sails, one attempt among many to exceed chemical rockets performance, these being inconveniently slow for hopping through our Solar system and beyond. Solar sails want to catch the light of our Sun to obtain a thrust which would indeed improve on rocket speed if the sail is big, the complete spacecraft light, and the push long enough. http://en.wikipedia.org/wiki/Solar_sail http://www.jspec.jaxa.jp/e/activity/ikaros.html http://planetary.org/ As far from the Sun as Earth is, incoming light has a pressure of 4.5µPa and reflected light as much, so accelerating any significant spacec…

The exergy concept describes both the irreversibility and the quality of energy but does it also describes the flows of energy in general?

Hello . I would like to slow down the car with an alternator (instead of pads). However, unlike a normal regenerative braking system, I want this braking power to be controllable. I wanted to ask if there was a CVT (Continuously Variable Transmission) gear available. On a bike we're driving, we can easily turn the pedals while in 1st gear, but we're forced in 7th gear. If I reverse the same logic and assume that the alternator is the brake in a car, can I determine the gear radius by decelerating the CVT gearbox to the brake pedal? Another example as applied to the engine brake is to reduce the speed of the vehicle at a certain speed and slow down the car if I increase th…

I was wondering the web and saw a Nikola Tesla video and saw that Tesla is applying high voltage, high frequencies. How exactly does Tesla do high volts and high frequencies at the same time? Does he use sound using an ancient amplifier and oscilloscope? XD or is it related to AC motors in which the currents oscillate and the faster the AC motor is, the higher the frequency/oscillations which then goes to a step up coil???

Hi, I know that when your car roll down a hill and you switch to a lower gear, the engine will break and the car slows down. I have heard that it slows down because higher rev in the motor and therefore there will be higher friction. I don't understand how this works, can you please explain?

Here is an german explanation of ufo engines. http://www.kompetenznetz-schizophrenie.info/forum/ Think about the bell when you move it up and down! Here is another tip... https://www.scienceforums.net/topic/117210-without-rotation-we-are-not-here-nothing-would-exists/

Simple school project: We're looking at a model of a generator. We have an iron core, spools of cobber wire and a rotating magnet. First we just test how much voltage is generated using different spools with different amount of coils - more coils equals higher voltage. Now we test which setup are most efficient in making a small bulb glow. It turns out, that 400 coils are more efficient than both 200 and 1600 coils. Reason of course, because the spools are of same size, so the diameter of the copper wire is different, and 1600 coils gives a very thin wire with high resistance. Person A claims, that the thin copper wire is also longer, and that will naturall…

Considering what it costs to set up to manufacture a specific CPU, I doubt there's much trial and error.

Hello you all! The "Krokodil" Ce 6/8II is arguably the most beautiful electric railway engine ever built, beauty and beast in one https://de.wikipedia.org/wiki/SBB_Ce_6/8_II despite the first delivery was in 1919, the design, with prow and stern traction sections connected directly, plus a driver cabin resting on both, still makes sense today for >6 axles, to pass sharp bends and spread the weight evenly on the track. So here's a modernized look for 8 axles, it could be 12 too: Marc Schaefer, aka Enthalpy

I was studying free undamped vibration, and i have this question What is the difference between the Natura frequency of a system and the frequency of any signal (f=1/period = natural frequency /2pi)

Hi all. Headache is possible. Am after ways to attach a properly sized plastic disc like this on top of the flatty portion of a marine compass dial : And being capable of adjusting its bearing in respect of the compass bearing. Yes, disasembling the compass, install it, and reassemble once. The hard part is the added 360o ruler disc (how is it called?) should be positionable from the outside. As when the compass indicates a -say 50 degree heading- the added disc to indicate a chosen shift -say aiming a 230o heading- Perhaps some perforation or method for halting the compass, and a knob? for the disc as way to turn the (friction? m…

Hi, I know that camshaft position sensors works by reading when there are blank spots in the camshaft. I wonder HOW it reads that. Is it magnetic?

I want to rebuild my house twice a year, what service should I be looking for? These are brick houses, single floor. How much does it cost? Keep in mind I live in Taiwan so I need international builders. No 3D printing please, they are not developed enough, although I like the idea

This morning, my wife woke me to the news that her coffee failed to heat in our big Sharp. It's a Micro/convection. I turned it on convect. and got heat, light lit, turntable turned, cooling fan running, so, FUSE OK. No microwaves. Power Transformer Diode Capacitor, or, (shudder) Magnetron. I could use a bit more information than my electronics training gotten 50+ years ago provides for me. Specifically, would the characteristics of the Magnetron used not need to be matched to the circuitry, namely the cavity and waveguide? Reason I ask this, I have substituted several different Magnetrons in several different makes and sizes of ovens, and they all se…