Engineering

Is it possible to power a drone from a set of capacitors, i did a rough calculation for the energy contained in a 380mAH LiPo for a toy drone battery, the equivalent energy required, as stored on capacitors would be equivalent to a massive capacitance of 730 Farads, most caps are measured in mirco fards. Im beginnning to think it capacitors will just be too large and clunky for the drone to carry even if it powers it.

Hi, I wonder how monochrome, sunlight-visible, transflective memory-in-pixel (MIP) displays works. Like the one on my Garmin Instinct. Does it work like e-ink displays? The more light getting on the watch, the easier you see the display. When it's dark you can't see it at all. Image below.

Hi, I wonder how devices like vapes for example can have the same wattage until the battery dies. Shouldn't wattage drop down when the battery level drops, because then the voltage will be lower?

I stumbled upon this ancient time-keeping device,The Chandelier Clock of Ibn Yūnis , The principle is simple, each lamp is burning a certain amount of time. You have to put in each lamp a specific quantity of oil in order to burn, the first for 2 hours, the second for 4 hours etc. With the subtility that in antiquity (& medieval times) the hour was not standard but it was a portion of daytime. When the day was short, the hours in sunlight were short & in night time were long. Here below the description of the object And here a couple of images I am seeing that the lamps are not at the same height. i see they are all connected (for sa…

I am designing a pervaporation membrane module to separate a feed stream of 81.57kg/h containing ethanol (90.3158wt%) and water (9.4955wt%), however I have now discovered that there is a trace amount of acetone in my feed stream (~1.887wt%). I was originally considering using a crosslinked poly(vinyl alcohol) as my selective layer to separate the ethanol and water. Is there any way to separate the acetone out first as I have a feeling it will disrupt my membrane quite a lot and result in a lower purity of ethanol in my retentate.

Hello you all! It is known, but not universally, and intriguing anyway: an RC network can amplify a voltage. No power gain of course, here a low impedance drives the network and a high impedance observes the output. The example network on top right here does that: It is best understood as a three-cell lowpass RC, as on top left, where the output was moved to other terminals, between what was the usual output and what was the input. The reasoning is valid because the implicit low-impedance generator stays at the same place. If, at some frequency, the network has some amplitude at the usual output with a phase between 90° and 270°, that is, it shows…

Descriptions of ground source heat pumps (GSHP's) talk about extracting heat from the ground for residential heating, but I haven't heard of putting heat back into the ground as thermal energy storage using these systems. Does anyone do that? Would it be efficient - or at least cost effective - where an oversupply of say, solar energy during warmer seasons can be used?

How significant are the effects of micrometeoroid impacts on interplanetary and interstellar travel? The ISS does have some issues with these, but would the space in between planets have them at the same rate? Additionally, would a generational ship traveling to a star say 50 ly from here with current propulsion technology actually be able to remain intact without some kind of ablative armor or shielding, or would micrometeoroids eventually erode the hull til it breeches?

Hello, I'm John. This is my first time here. I wanted to get like a 12 can cooler bag and make it with a battery pack so that it is cooled by a compressor or something. I was wondering if you guys knew something that is small enough to fit inside the cooler bag and still leaves room for things.

How do you calculate how many grams of kilograms of neodymium you need in order to build a permanent magnet motor with, let's say 10kw power? Thanks wasn't sure which forum to choose to post this.

Hello all. Would a container like made of a thin flexible material -like silicone- Exposed to sound waves; and a microphone on the cap at the neck, yield louder readings by amplifying all contractions/expansions of the spheric portion into a longitudinal up/down vibration into the neck ? In other words, a microphone in a tube attached to the neck of an elastic balloon; would it behave as a sound magnifier ? Would it be similar to a microphoned hearing funnel ? And the narrower the neck, the greater the magnification ?

Hi, I understand the principle of how PDAF (Phase Detection Auto Focus) works. Look at the image I inserted. I don't understand how the incoming light splits into two rays of light in the two extreme sides of the lens. Why aren't lots of rays of light coming all over the lens? Source: https://photographylife.com/how-phase-detection-autofocus-works

Hi, Let's say that the watch in this example is AMOLED so that the battery usage depend on the color of the display: When smart watches go to ambient mode the background of the screen turn dark (in most cases, some just reduce brightness of the screen) and the rest of the watch face turns white. I wonder why the rest of the watch face turn white, which is the most battery consuming color to display, rather than red for example, which only require the red led to light up? I know that it's easier to see white, but red would save more battery.

Please pardon the crude illustration, this is merely meant to make it clearer where I'm going with this. I'm picturing a power source; I'm not sure whether it's already covered under the "geothermal" umbrella or not; that uses the heat of volcanoes to turn turbines through steam. The idea is that water would be pumped into an active volcano, and a tube would be placed at or near the top to contain the resulting volcanic gases (or at least most of them) and use the force applied by their escaping; or at least from the steam escaping; to turn turbines. This leaves me with a few questions. 1. Would this be a "renewable" resourc…

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 …