Engineering

Hi everybody! Last time I saw an instrument needing excellent mechanical stability (a tunnel effect microscope) it was built of metal. But microscope mirrors, which have similar needs, are made of a special ceramic. One known example is zerodur by Schott. So could such instruments be made of zerodur or similar? Besides the much better expansion coefficient, I ignore the properties and fabrication abilities. Mirrors are ground but make big efforts to cast the near-net shape, so deep grinding is unclear. The cost is an interrogation as mirrors take several months to cool down. Chemical etching woud be nice. Assembly is unclear, electric sealing would be …

I always noticed that deodorant sticks become uneven after being used for a while. It doesn't bother me, but has always made me curious as to what exactly is the scientific process that does something so bizarre yet so interesting. I've always found nature's effects on modern technology as well as humanity itself to be an interesting study.

Consider a system with fluid 'A' of sp.gravity 's1' is having certain leakage 'Q1' into the surrounding through geometrical imperfections(pores). Now if the fluid is replaced with another fluid 'B' of sp.gravity 's2' ,considering all the other system parameters like pressure,temperature etc remain the same,how will the new leakage change through the same geometrical imperfections(pores)

Hello you all! Magnetorquers serve to control the orientation of smaller satellites in low-Earth orbit. A set of big air coils, or small coils on soft magnetic rods, create a torque in the geomagnetic field. I propose instead to use an aggregate of magnetic materials and tilt it versus the geomagnetic field when wanting a torque. One aggegate serves for all directions, gaining mass over fixed rods with varied orientations. Creating a field but stronger than Earth's one suffices to orient the permanent magnet, and this takes far less power than usual magnetorquers. A big Leo satellite can be 6m*3m*3m and 15t with 56*103kg*m2 inertia. If willing to supp…

Hi. Has any manufacturer come up with some 3D copier yet ?

Greetings. Seen a couple of machines that melt shredded plastics in used hot oil for the process of recycling. Seems there is not much mixing as plastics being heavier, stay submerged by the bottom of the vessel in a nearly liquified state layer. Seems the oil is just the media to convey the heat source thoroughly. What would differ choosing used motor oil, used vegetable oil, used transmission fluid, used hydraulic oil ? Would any be more convenient than other ?

scientist make a AI that can draw and paint... Well it looks like we have AI system that can draw and paint. https://www.christies.com/features/A-collaboration-between-two-artists-one-human-one-a-machine-9332-1.aspx Well it looks like AI that can draw and paint is coming out faster than we thought.

What could be done in order to store liquid methane at room temperature? Possibly some "super-additives" which are capable increase boiling point dramatically?

Hi. Do these F1 racing engines use a coolant thermostat ? In the liquid path; not louvers at the air flow path.

I have come to accept that when an induction motor receives lower voltage than it was designed for it will pull higher current. This doesn't make any sense to me, but I have seen it stated enough times that I'm willing to believe it. Everywhere I look provides total nonsense explanations. They say things like "the motor will draw more current in an attempt to maintain its torque" as though the motor has agency and chooses how much current it draws, or "in order to provide the same power" as though the motor cares how much power it provides. The version that would make sense to me is you have a resistance, both in the actual windings, and in magnetic impedance(?), and…

I'm not here to knock Boeing. They have achieved fabulous stuff in the past. Great planes, breaking new ground, setting records. But there is no way I'm ever going to take off in a 737 Max. From what I can glean from the two crashes that grounded the fleet, the design is cobble up, and needs everything to be right, in order to keep flying. I want a plane that nearly flies itself, not one that needs special software, and top quality piloting just to keep it from crashing. I believe that the whole problem is due to moving the engines forward, and enlarging the intakes, in an effort to compete with the equivalent Airbus A320. This apparently affects th…

1. How much of an effect does a magnetic field do to electricity, i mean bare electricity, as in, its not in a wire or something. 2. Do the poles of a magnet affect the movement of electrons eg: attracting electrons and repelling. (I know very well how motors and generators work, no need to lecture me about how e- flows through a wire coz thats not what Im trying to point out.) 3. Will it be possible to make a magnet attract electrons from one of it's pole, throught the magnet, and releasing/repelling through the other end? 4. Does north and south poles affect negative and positive? 5. Please discuss this: https://arstechnica-com.cdn.ampproject.org/v/s/ar…

Does anyone have a good design for a paramotor? And are there any good alternatives to a flying vehicle that can also carry other humans other than planes and helicopters (That is also as cheap to build)?

Hello everybody! Frequency filters lets signals within the passband through and attenuate everything in the stopband, for instance noise or an adjacent communication channel. Much theory exists for them, works nicely. The stopband attenuation can be big, and the "selectivity", the ratio of the nearest frequencies of the stopband to the passband surprisingly small. But as the frequency response gets sharper, the time response gets slower and bumpier. No wonder, since a Fourier transform links them, like the diffraction rings of a lens, or the noise created by jpeg compression, or Delta(t) and Delta(E) for a particle. I'll consider only lowpass filters here. …

Hello dear friends! I believe it is known, but not universally: a quiet amplifier can synthesize a quiet resistor that produces less noise than a physical resistor at the same temperature. Amplifiers can be very quiet. Under S/N=3dB they add less noise than a resistive source at 300K produces. Good RF preamplifiers of usual technology at room temperature can offer S/N=0.8dB, adding 20% to the noise power of a resistive source. Cooled or exotic RF preamplifiers can be much better. Audio amplifiers can add even less noise, especially FET amplifiers on a high-impedance source. Here the amplifier with gain -A shall have a high input impedance to simplify the co…

Shown on some reports of third world innovative diy gadgets, they have a led lighting a water filled soda bottle. (This is not the 'skylight' similar approach that funnels sunlight and rain leaks into a dwelling) How does the addition of the soda bottle optical losses improves illumination than the bare led alone ? The difference I see is it creates a non-point of light emission by being a bottle-sized body of emission with some according gentler pupil reaction. Now, the "old" battery mentioned. Why old ? Next, about the skylight bottle. Why is it perceived better than a transparent piece of roofing ? Is it from the strong habit in modern off…

All of the electrochromic film I have seen for sale operates on the principle that when electricity is applied, the film becomes clear, and I understand why that is...but is there an electrochromic film on the market which operates in the opposite way? Is there a film which remains clear or semi-clear until electricity is applied, after which the film becomes opaque?

How do I make a coil or a series of coil constantly move electricity as the magnet passes it in half of a circle/armature. Do I simply make an oval shaped coil that covers the area I needed cover, or do I make a series of coil? Think of it like a motor but instead, the coils are only on half of the armature.

If I needed to generate an adjustable current up to a maximum of .000165 amperes, what would I use as a power source?

The engineering that goes into this aircraft is amazing! I've never seen anything fly like this other than a frisbee!

That 2001 movie and its turning module to make gravity seemed within reason... Why has not been pursued ? No need for it ? Cost ?

I'm asking for suggestions in various categories as some of them might be more important for coursework whereas others might be more recreational and to expand knowledge. I know for example that Knoll is the go to for radiation detection and Lamarsh and Baratta is the most important for intro to nuclear engineering (of course some disagree with dumbing down in it, which is why I ask). Any books that anyone would like to recommend as a must have for core nuclear courses? Other books that I'm looking for are more for my knowledge. For example, I found introductory nuclear physics by krane really helpful in explaining some of the concepts and bridging the gap betwe…

I've been trying to put the math together for this, its out of my league. What i need to answer is: if each charged plate strips/adds electrons to the air molecules they touch, will this configuration of insulators and charged plates produce positive thrust along the main Y axis? -DT PS, "Tah-Dah!"

You can create your own desalination pit in your back yard. Just put a clear plastic sheet over a kiddy pool and have the plastic deliver condensation into a central bucket. Why cannot humanity build desalination containers to float off-shore, like a fleet of a hundred (or thousand, or million) canoes covered with clear plastic. They float on the ocean allowing just enough water into the container so the sun can heat it and the condensation can flow through pipes or hoses towards shore. These containers can even be connected by "wigglers" that generate power from wave action. We could irrigate great deserts to grow trees to capture greenhouse gasses and d…

Hello everyone and everybody! The elastocaloric effect is one more fascinating behaviour of NiTi alloy and other materials including rubber. NiTi, whose crystal can change between martensitic and austenitic easily and often reversibly, is known as a shape memory alloy. But as the heat of formation of the crystals differ, the transition absorbs or releases heat, here when provoqued by mechanical stress. Refrigeration and Niti on Wiki Research tries to build fridges, air conditioners and heat pumps using this effect. NiTi operates around adequate temperatures, survives many cycles, offers some 30K swing, and promises efficiency at least when exploiting its full …