Engineering

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…

Hi. Is there a replacement for typical metal HVAC ducting in CPVC, PVC, FRP, other rigid plastics, in 15cm(6") to 30cm(12") ? Something with smooth inside surface, to be insulated on its outside ? Perhaps ~1mm wall with available elbows, tees, connectors available ? -Not flexible 'hose'- What is 'schedule' 5, 10 ?

Hello everybody! You know hydrogen is thought as a way of storing energy, before transformation in a fuel cell for instance. Storing liquid hydrogen isn't very easy because it needs really cold temperatures, and pressurizing gaseous hydrogen needs heavy tanks with little capacity, so research is being done to adsorb hydrogen in a solid in the hope to store much hydrogen in a small volume under reasonable conditions. My own two-cents suggestion is to use abnormally light metallic alloys for this purpose. That is, alloys whose volume is bigger than the sum of the volumes of their constituents. My hope is, of course, that more free room is available to hydrogen in the allo…

The shank on this brush is 1/4" (6.35mm) and I want to reduce it to 6mm. Would using a 6mm die be the simplest/cheapest way or would the metal be too hard? It doesn't matter about it having a thread. I have a rotary tool that only takes 6mm bits. I've tried manually grinding one on a grinder but it was a poor job and quite off-centre. I've also tried buying 6mm bits twice but they are 1/4", despite the fact they say they are 6mm.

Hi. It has not changed much for centuries. Can there be a more ingenious, efficient way with modern technology ? The mechanical separation of heavier metals by vibration immersed in water, by a weight differential that also exists in dry process smells that could be improved. The weight differential when dry and the weight differential when submerged is there in both cases. What would be the process for evaluating efficiency ? Running the discarded material on a different process to confirm obtains additional separation ? Seems like laminar flow is important, but the fluid flow being used to carry the undesired solids destroys the laminar flow. Ho…

I previously discussed, as part of a broader thread about flood mitigation/adaptation, the notion of concave-up ellipsoids over cities to collect rainwater and prevent flooding. It was noted that they would be weak at the bottom, because of the immense pressure of all the surrounding water. On further consideration, cities are probably not the best place to put them in light of that. However, thinking about this further, I've since come up with another idea; a concave-up rain-collector (whether as ellipsoid or half-cylinder, depending on whichever is more practical) at sea, directly underneath the intertropical convergence zone. This way, rainwater…

Hello, We have developed new type of permanent magnet synchronous motor, performed a patent search and did not find anything like this. http://motresres.com/branding/toroid...rical-motoree/ May be someone saw something like that before?

I am trying to find a Node Editor GUI, preferably for python, which would allow the creation of new nodes from certain selected folders and files which already have code inside of them.

New consignee: saw no location for introductions......retired dual-discipline Engineer, Electrical-Mechanical. Have not entered any personals yet, save your time! My lifetime interests have ranged from fast cars, I.C. Engine work, High-voltage experimentation, explosives, in short, any of the things often considered "bizarre" by those outside of my little world of interest. Multi-forum member, rarely encounter many members interested in things technical. Several airline pilots present on a seniors forum presented interest, but my difficulties with an uncaring forum owner ended rather, er........ironically. I am a tinkerer, at heart.

This video showed the construction of a modestly large concave mirror using a fairly meticulous process of carefully placed reflective foil. However, I would presume that, the larger the scale on which it's conducted, the less any wrinkles in the structure matter, at least for the purposes of collecting sunlight. I'm wondering now; is there any cost-effective way to have outer space robotics (Canadarm, etc.) assemble a giant amount of reflective material in outer space? Would electrostatic repulsion and/or magnetic attraction serve to force a giant sheet of reflective material into a concave shape? Could this concave mirror then be used to melt the…

Four pistons, laser flash for thermic nitinol

For pure metal production and power