Engineering

How do I calculate the resonant frequency of a structure?

Don't know where to put this thread. I want to know: Which is better to use plastic to create armor to combat street hooligans? It is necessary that the knife could not pierce armor.

Hey, I'm looking for a magazine, a website or other, where new achievements or opportunities are presented. Well, let's say this: in principle everything is interesting, (at least for me) any new development, including breakthroughs or other. New things that came up or new ideas ... I'm really interested in many aspects, but especially on the technical side, as may soon be usable new technologies, no matter what aspect (weapons, robotics, aerospace, automotive, motors, ...) but also things like medicine (new drugs, treatment options, implants) well, so almost everything in the natural sciences area. However, I do not care about any gossip magazines or something like tha…

I own a 2007 toyota corolla (stick shift ). The engine is a 1.8L with a 10:1 compression ratio (stock). Should I be using 87 octane or 89 octane due to the 10:1 ratio? ~ee

"Mining the Sky" for Earth? Why is there only talk of bringing it back down to Earth? What would we even do with such resources? Most Sci-Fi resides beyond Earth. Megastructures are under my eye (i.e. spaceships, Dyson spheres and artificial worlds!) Zero-gravity provides a very free medium which should simplify automated construction. Automatized production systems could be highly modular, reproductive and self-maintaining; principles which yield a system capable of building virtually anything we can imagine that is theoretically-feasible! I think we should do our best to live within the confines of Earth and crunch down as much efficiency as we can bef…

This should be explained... link deleted

Hello, I am Scilight! Some stuff about conversion. Can't you convert speed to tourqe through methods of gears?

Thought it was kinda cool.

Hello everybody, I am Victor Moussalli, 17 years old, just starting grade 12 of high school. My passion is energy efficiency. The only types of engineering that I like are: environmental, energy, and electrical. I want to know what is the best path to take; university or not, to guarantee a good job later on as many of my older buddies are now struggling to find jobs despite their engineering majors. Thank you, Victor Moussalli

All it takes is flexible paddle wheels attached to generators biting into the flowing river surface.

This is a device typically seen in fiction. Or if you're like me, you might have actually considered them as a kid. But I'm still wondering about them today, and curious if they're really an impossible task. I'm talking about manned ornithopters, capable of allowing a person to fly and land safely. The contraption is either wearable like a backpack or a light vehicle (similar to a bicycle), and powered by pedaling or using your arms (no engines or electronics). Obviously, they would be for one person only, and useable up to altitudes where low pressure and temperature aren't a biological hazard. Although a fantasistic idea, I'm well aware of the limitations. Unlik…

I'm sure you've heard this story 100 times. Basically, my friend and I got into a BIT of an argument about the purpose and use of mechanical engineers and mechanics. My friend who is a mechanic, works at this factory and managed to modify this machine to make it run better/ more efficiently...and essentially got to the point where he said mechanical engineers are just overpaid mechanics (as he could easily improve this machine), and that they got their chins up high thinking that they're better than mechanics. Naturally I tried to explain what mech. engineers do. Then he said "why do you need dynamics, statics, or calculus if a mechanic can fix and make this machine b…

The Honda RX-8 had a couple of unique features, including a Wankel (rotary) engine, in contrast to the piston driven engine that most schmoes drive (like me). However, what is the attraction of a rotary engine. Can it possible be more efficient than piston driven cars? And if not, why use an engine that is even less efficient when so many of us are trying to reduce our carbon footprints? Rotary engine

How would crews get to Mercury? Is there any way we can beat the high delta-V penalties for classic style ballistic flights? Yes, there is: Cyclers. Mercurys orbital period is 87.97 days. Earths is 365.25 days, or 4.15 Mercury years. A cycler deployed to a 351.5 day orbit, with Earths orbit as the aphelion and Mercurys orbit as the perihelion, will encounter Mercury every time it (the cycler) reaches perihelion. Crews departing Earth would still have to generate a high delta-V. In fact, cycler missions would require a delta-V around 9.5 km/sec. while some standard (Hohmann) transfers can be done for 6-7 km/sec. The difference is that a cycler mission puts most of the …

As far as I'm aware lead acid batteries have to be maintained in an upright position. Well, perhaps I'm wrong because upon disassembling my large recently expired rechargeable torch, I discovered its battery mounted on its side. Which I'd have thought not conducive to the liquid being able to cover the cells. I might add that the torch is not very old (it wasn't cheap either), and my thinking is its premature death is because of the battery mounting. Has anyone any thoughts?

How many square feet of solar panels would be necessary to power a bicycle? I'm imagining a bike with little solar trailers.

I have an old leaf blower with a 25cc 2 stroke engine. The plastic casing cracked making the leaf blower useless, but I took the out the engine and it is perfect condition. -Any ideas on what I could do it (besides sell it)? I don't have ALOT of tools so I can't mount it on a bike but that would be hella sweet though. -Thanks ~EE

We have been watching and playing with personal drones for the past decade. I even have a toy helicopter to play with. There is now talk of having pizza's delivered via drone, although I expect every kid with a BB Gun is holding his breath for that day. Here is something nobody talks about. Lets pretend you buy a Drone with a 30 minute battery capacity. What is to prevent you from adding photo recognition to the camera and a tiny sawed off shotgun type attachment. People will be able to kill each other simply by showing a photo to a machine and sending it off in the right direction or hover in your driveway. All of this technology exists and has likel…

ok Water boils and transform in to steam in room temperature at full vacuum. why can't we use this method to desalinate seawater. we don't need any fuel for heating water but just only energy need for maintenance ,pump water ,make water containers full vacuum

Hi all Just an interesting thought. Would it be viable to extract the energy in a dam as an aside to running the turbine with it. Just how efficient is it now ? Since the water is already being dropped on the turbines , would it be efficient to use part of that process to run the same technology as we use in our homes to create heat for different generation at the same time. I would imagine the heat to be extracted from the dam body and the same water as runs the turbine to run the heat pump. I'm not claiming to know a whole lot about heat pumps except they are extremely efficient. Cheers iseason

Extreme events such as impacts, ballistics, explosions and blasts, which occur at very high pressures, and very high speeds, is difficult because of the highly specialized diagnotics, really involved physics and the computational methods which are generally very niche. The one major advance in recent years is the advent and ever increasing availability of very high frame rate and high spatial resolution cameras in combination with the ability to store and process rapidly the very large amount of data generated, together with the development of batch image processing techniques as well as free software such as imagemagick, gimp, ifranview and many, many others. Thi…

What's more powerful the human brain or a quantum computer? And by how much?

I am designing a dream boat approx 100' in size and likely to use Junk Rig sails for ease of use as I would like to sail/power around the world and visit more archeological interesting countries. I am now imagining a 45° angle of a wide and deep reinforced transom below the water line to add thrust from pitching. The idea is based upon other wave power models Example video... https://www.youtube.com/watch?v=UWpxtfmpVD4 Instead of using the rear wing as in video I would only capture the downwards pitch in my design. There is a Wave Powered boat that has crossed The Pacific (to Hawaii from Japan). Any ways to stop the bow from having reverse thru…

Why do I not see these being attempted more often? A plasma railgun works the same as a regular railgun, except the armature (and projectile) is ionized gas instead of anything physical. Now, the differences I would imagine are thus: -The voltage would have to be very high - typical Jacob's Ladders take about 6 kV from a transformer to ionize air. - Because the projectile isn't solid, it has a lot less friction (and therefore a lot better acceleration and force?) Would the capacitor bank be different? I'm not sure whether plasma would need more or less energy...

Does anyone know about these methods of harnessing energy? I've seen "wigglers" that generate power from surface waves. How about these 2 ideas: WAVE POWER - Standing on a pier at the beach looking down at the water, you see the waves surging towards shore and then the backwash flows back out. Suppose you built a pier-like structure parallel to the shoreline, maybe a mile or more long and about 50 feet wide. Suspend paddle turbines over the water just touching the water. As the water flows towards shore it spins the paddle turbines one way, and the water flowing out spins them the other way. TIDAL POWER - If you build a wall along the shoreline to the height …