Engineering

And if so, would any telescope pointed at the moon be, in turn, de facto surveillance of any position on the face of the Earth? (For good or for ill; anyone looking to misuse this technology would probably come up with it independent of our discussion so best we discuss whether it'd work before we come to any conclusions on whether it'd be something that'd need to be stopped if useful.) I ask this because I was recently thinking about this involving their counterpart in the form of concave mirrors: Which while the image quality isn't ideal, one can still get a rough idea of what is going on in the reflected image. I'm t…

Hello everybody! Rockets must be light to attain a high speed, but their thin structures, pushed by the engines, are threatened by buckling. Usual tank construction includes sheets milled down to an isogrid structure, or omega stiffeners welded on a sheet. I propose to assemble rocket structures from tailor-made extruded profiles instead. http://en.wikipedia.org/wiki/Extrusion Extrusion can produce thick profiles consisting of thin walls that build closed channels. Such walls are well supported hence strong against buckling. The extrusion direction parallel to the rocket axis has advantages. All walls bring strength against rocket bending moments and axial co…

I suggested repeatedly to electroform Ni and Ni-Co, possibly allied with Mo, for music instruments and more scienceforums and later and elsewhere Strong electroformed alloys would serve many more uses. For instance rocket chambers are of nickel electrodeposited on an inner copper jacket where cooling channels have been milled. But what alloys might be possible? Please remember I'm not reliable on electrochemistry. Strong nickel alloys are known, mainly for superalloys used in gas turbines. They consist of Ni, 20% Cr, 0-20% Fe, <20% Co, <10% Mo, <5% Ti, ~1% Al, Nb, and some more. Nice source: Nickel and Its Alloys, monograph 106 by the National B…

What money does When one uses money to do something, the usage of money reduces the time and effort one has to spend to do this something, because if you REALLY think otherwise… When one uses money to do something, the usage of money doesn’t reduce the time and effort one has to spend to do this something, but if you think this is REALLY ok for you… If in the end, when one uses money to do something, the usage of money doesn’t reduce the time and effort one has to spend to do something, it doesn’t seem to me one knows how to use money…does it seem to you…idiot? Who is good at making money When one is good at making money, one …

Boeing 737 max - does the system give 15 seconds for pilot to disable the autopilot system?

Hello, heirs of James Clerk, Nikola and the others! It is well known, but by too few people : in an electric machine, only the force means losses and heavy parts, the speed comes for free. When a motor or generator runs quickly, say 50 or 100m/s at a power plant, it is smaller than a turbine. Quick machines with rotating permanent magnets use to hold them in a tight sleeve of strong steel to counter the centrifugal force. I propose to wind a composite of graphite fibres around the magnets instead of the steel sleeve. Graphite fibres are lighter than steel and produce less eddy current losses where they cross the stator's windings; better, while the accurate diamete…

Now, for a bit of social and urban engineering trivia, here's Kowloon, the walled city of Hong Kong: https://www.businessinsider.com/kowloon-walled-city-photos-2015-2?r=MX&IR=T

Hello Everyone, Recently my research work investigating the quality of engineering skill in the UK was peer reviewed and published. I'm am trying to publicise this research as much as possible to hopefully make some real changes to the educational systems for engineers in the UK. Please have read, the below link is where you can download the paper, feedback is welcomed. links deleted Thankyou, Sam Edwards. BEng (Hons), IEng, MIET.

So the question arises, why be at the bottom of the sea? The international space station has a lot of scientific experiments that can only, or best be performed in microgravity. So I ask the question what experiments can best be performed at the bottom of the sea? What comes to mind is the pressure. Immense pressure. Almost 2x the pressure that we can generate with pump technology. 690bar seems to be the upper limit of pump technology, but Challenger Deep rests at 1014 bar. And so I suggest that there is opportunity for experiments here. Enter the "Diamond Anvil Cell." https://home.hiroshima-u.ac.jp/kawazoe/html/Kawazoe04-Method-EN.html https://www.scien…

In continuing my series on a deep sea base, another hypothesized reason of being there is biotechnology. This one seems more probable than the diamond anvil cell. The most obvious need is to research piezotrophs in their natural habitat. If the lab can be ambient pressure then the lab really can just be as flimsy as tin foil. Not literally, but relatively speaking that's still true. The problem of deep ocean comes from pressure hulls and ballasts that can survive those depths. Even the best ballasts, syntactic foams, are likely to crack and their failure means the loss of the lab to the Deeps. Enthalpy has shown some other interesting solutions to ballast, but u…

I call it the "hydrolock". People may not realize, because often times "space" is considered the most difficult frontier, but there currently is no docking system for deep ocean. If you want to go to the deep ocean you have to enter a pressure vessel on the surface before your long descent. We are basically at the Mercury mission stage if comparing deep sea exploration to space exploration. Space was easy for a reason I'll mention below. I've been working on this thought problem about how to create a docking system for deep sea bases. It's not as straightforward as one might originally think because the system has to: 1) maintain hull integrity the whole time.…

I've been looking for a reason to put people at the bottom of the ocean and there aren't a lot of practical reasons. ROVs can do most or all of the work. But I think I finally found one reason that makes sense. Hydrogen is the best rocket fuel but not not long journeys because the tiny atom leaks from the tanks. However metallic Hydrogen will not have this problem. Metallic Hydrogen also seems to have a boost in efficiency by 4x but I don't understand how. However the diamond anvils needed to press Hydrogen into metal are at their limit, right at the limit apparently. So what if we put the diamond anvils at the bottom of the ocean? That will add some 1000at…

Injecting hydrogen in the divergent of an engine downstream dense propellants was experimented long ago. But if the dense propellants are pressure-fed, I claim one can build a (mainly) oxygen-hydrogen engine without pumps. This isn't normally done because hydrogen pressure tanks are too heavy. Figures are just examples to help understand and check. From pressure tanks, scalable 1kg/s oxygen is fed in the chamber and burns only 28g/s alkane at 80bar and 1056K. Expansion to 27.2bar converts half the enthalpy available in the hot gas, so the gas can't flow upstream, and it builds a vacuum downstream a sharp obstacle. There, hydrogen ducts end facing downstream, which su…

Why did SpaceX lie about this? This is a serious lie. Falcon Heavy only has 3.4million lbs of thrust. Orbiter had 6.78mil lbs of thrust. What is the purpose of this lie? SpaceX also lies about: 1) being first to have reusable rockets. All of Orbiter was reusable except a single fuel tank. 2) being first to have a reusable spacecraft. Orbiter was reusable. SpaceX also claims achievement in areas that are not achievements. 1) using Methane fuel. This goes backwards from Hydrogen technology. 2) being able to land a rocket. Apollo landed rockets on the Moon just fine. Earth rockets just fall into the sea to recover them.…

A number of my past posts relate to hypothetical alternative sources of electrical power. I'm wondering if it'd be more efficient (pun intended) to coalesce them all into one megathread, such that people could compare and contrast these hypothetical proposals. I'd like to reiterate all these proposals, and a few new ones: A. One common criticism of household solar panel rooftops is that they're vulnerable to hail damage. I'm not sure if there's some way to mitigate this vulnerability that the fossil fuel industry doesn't want us to know or whatever, but in the meantime, since thermal solar isn't as vulnerable to hail damage, would a better approach be to have …

In few years hydraulic fracturing has revolutionized the world of energy by the production of shale gas and shale oil. It is perhaps possible that fracking can reach another resource in the depth of the Earth: gold. A new theory established by geochemists (1) describes a transport of gold by trisulphide ion in hydrothermal deposit. Trisulphide ion chelates gold and facilitates its transport towards the ground surface by water. But the stability of trisulphide ion depends of temperature and pressure. Trisulphide ion decays at a depth of some kilometres and leaves a first deposit of gold. According to this theory, a second transport by chloride and sulphide ions e…

Look. Musk is NOT a genius. As a person intimately involved in his Gigafactory debacle: 1) his factory is STILL at 25% capacity. Panasonic rightly took over most of the slack making bank of Musks flaccid manhood. 2) lithium ion tech was ALWAYS a dead-end. It's still a dead end for the same reasons now...there's not enough of it and the Chinese own most of it. 3) Capital structure locks TESLA into a death spiral as technology moves away from Li-ion and other car companies move into hybrid solutions for EV vehicles. Why does this matter for SpaceX? 1) Dragon capsule is a spruced up Apollo/Soyuz design. Nothing new. Actually it adds a significant pro…

I would like to take the time to present an idea I have come up with. Please note that I am a layman when it comes to the field of rocketry so please keep this in mind My idea is " The usage of a ferromagnetic fluid, such as ferrofluid, as a replacement of conventional rocket fuel in order to develop a rocket engine which would have the potential of recycling its fuel continuously through the usage of motor pump technology. All the while containing both the rocket along with the fuel and other components of the engine inside of a casing so that the different fluids do not escape from there respective housings. (Here is a general image of the idea that I am …

I am studying electrical engineering again and have read that the electrons travel from the negative lead to the positive one at a very slow velocity. Now the book states that in order for the mechanism for voltage to work an electron accumulation or "build up" occurs at the negative lead and when a non-zero resistance in placed between the positive and negative leads an impulse of energy is sent through the conductor which connects the positive and negative ends of the battery. My question is, as seen from the title, if that pulse happens continuously then how fast are the electrons building up or accumulating at the negative end of the battery. What would this depe…

Hi, Sorry for this huge post. You've been warned For this to make any sense at all, i must first explain a bit why i'm thinking about room cooling and make a post in this forum. I'm living in an apartment in The Netherlands on the first floor. I have neighbors on my left, right and above. Below my apartment are storage rooms. The ceiling of those storage rooms (that would be my floor) are covered in hot water pipes. If you see my apartment as a rectangle then the two long sides are made of concrete, the walls between my apartment and my neighbors. The remaining sides are just the façades where there are windows with double layered glass. Of all the r…

Hello everybody! The gas generator cycle is widely used on rocket engines, but some variations are still possible and desireable. For instance, the Falcon launcher burns the derived flux with much kerosene and little oxygen to limit the turbine's temperature, but the resulting soot complicates the reuse of the engine. One alternative, similar to Ariane's Viking, would add water to a tuned mix of RP-1 and oxygen, injected in two steps. 107:10:34 results in 873K=600°C; expansion from 50bar to 5bar gives 1133m/s. Good solution with one pump more. If accepting additional propellants, (yuk!) hydrazine or MMH, hydrated for 600°C, give 2004m/s and 1696m/s - not fully …

Hey Everyone, newbie here. I'm aiming way over my head here, but was wondering about something has been bugging me all day. At 70000 feet ( 21km) passed the Armstrong Line fluids start to boil, due to the atmospheric pressure, producing steam and therefore energy. Now, its like -56C° at that altitude and possibly colder in the Mesosphere. Does Liquid Hydrogen create enough energy once it has reached the Boiling point of -252C°? Even though liquid hydrogen has low energy density, and has high specific energy. Could a plane with a fully pressurised cabin, something larger than a U2 jet, be powered by a Liquid Hydrogen steam powered engine/jet propul…

Hydrogen fuel cells would bring big advantages to helicopters. Fly long! Airborne 1t including passengers and fuel takes ~100kW with 78m2 rotor(s), say mean 130kW with the manoeuvres: that's two Honda Clarity fuel cells of <100kg each. 48kg hydrogen keep it in flight for 8h - that's 100kg with the tanks I described there http://www.scienceforums.net/topic/73798-quick-electric-machines/#entry738806 Electric motors save maintenance, expensive and long with gas turbines. Electric motors are easily spread among many rotors, leading naturally to quadtoror-like designs. This is way easier than the pitch of common helicopter blades, which changes over a turn. http://en.wi…

Online, it seems a lot of sources say LIDAR doesn't work as well as RADAR in rain or humid, dewy weather. Maybe it's obvious, but I was essentially just wondering why. Why does water in the air affect light waves more than radio waves?

We have a thread on comparing electric to heat engine powered vehicles, but this and a recent discussion elsewhere inspired me to consider passenger cabin heating in electric vehicles. IC engines have the advantage of a readily available heat source. Does anyone have any data or experience of how an electric car is heated and how much energy this takes ?