Engineering

Overheard a conversation about car tires. One person said that instead of air they just use Nitrogen. Why use nitrogen, what is the difference? Could we therefore fill our car tires with helium to make them lighter, or even .... float? What challenges would a helium filled tire face?

Wikipedia - Florida International University pedestrian bridge collapse The Florida Department of Transport has released the engineering design and construction plans for the FIU pedestrian bridge, which can be downloaded from this link. Florida Department of TRANSPORTATION - Denney Pate signed and sealed FIU bridge construction plans - 2016 & 2017 https://cdn2.fdot.gov/fiu/13-Denney-Pate-signed-and-sealed-FIU-bridge-construction-plans.pdf My analysis of these engineer's plans have revealed that my earlier suspicion that member 11 was dangerously under-reinforced has been confirmed, to such a degree that the collapse of member 11 (and cons…

If you haven't heard, an American Southwest flight, 737 was flying from Newark to Dallas. The plane's left engine (?) blew up/malfunctioned. The pilot (former Navy fighter pilot) was able to land the plane. My question is how was the plane able to stay in the air as long as it did, and descend, turn, and land with only one engine? ~ee

Dear All, I’d like to share an experience with the fall of potential method: if I call E the electrode under measurement (in a square arrangement of approx. 20m), P the inner Potential electrode and C the outer current electrode, I could get a flat curve of the E resistance whilst C was away from E by a distance corresponding roughly to the side of E. I was quite surprised since I thought this distance was too short and I expected a non flat resistance curve since E and C were supposed to couple with each other. Hence a question: can you theoretically get a flat curve when E and C voltage gradients still significantly overlap and, if so, does it necessarily m…

I'm currently looking into and buying machining burrs and cutters. It seems some sellers pass off HSS as TC. Do TC cutting/grinding tools have a particular colour or texture to them?

I can only find unsubstantiated forum opinions on the net. Any idea what the correct spec for an electric die grinder with a range 3000-30000 RPM is? Would grease designed for petrol strimmer gear heads be ok - I think they run about 10000-12000rpm? Would it be classed as high speed/low-load or high speed/high load or high speed/high temperature grease that's needed? It's 750w. It takes 6mm shaft diameter bits. The heads on mine are up to 15mm diameter.

Dear All, Suppose I have two parallel conductors of different lengths in a homogeneous soil of resistivity Rho, and separated by a height of H. Is there any existing formula to calculate the mutual resistance (in DC) between them ? With my thanks.

Hi all. If I publicly display/explain a new product, idea, design, prototype, application, demonstration movie of its operation in a forum or this forum or anywhere public site on the web; would that prevent from being patented by anybody else, as becomes public knowledge 'existent since the date of disclosure' ? My patent lawyer explained something in that line a loooong time ago. Would it be effective ?

So, obviously producing antimatter in an accelerator and using this to annihilate with regular matter is beyond uneconomical if you want to produce energy. What I was thinking of was producing positron-decayers, since every electron-positron annihilation would yield two gamma-rays with 511 keV, and the positron itself coming from the nucleus has kinetic energy, too. The question is, since positron-decay happens in atoms with 'too many' protons like Oxygen-15 and Nitrogen-13, how much energy does it take to knock a neutron out of the core, and how reliable is the process? If the reliability and the energy input per atom is below 1MeV plus whatever the positron's kinetic en…

Don't you think in this modern age if some country decides to attack another nation with nuclear weapons they would NOT use ICBMs? With so many satellites in space watching every country, would it not be easy to determine the source of a nuclear missile launch? The source would be promptly punished. For that reason, to maintain anonymity, I would suspect that IF it ever happens, the nuclear weapon would be discreetly delivered to it's destination by a boat, small plane, truck, or even inside a car. Then nobody can tell where it came from.

I am glad my equipment has a safety pressure valve on it.... :-/ I have 2 Nitrogen cylinders feeding a TGA machine and other cylinders feeding other machines with Oxygen. The O2 line has always been fine. The pressure regulator on it is quite expensive. The pressure regulators on the N2 cylinders seem to allow high pressured gas surges through the line. I have set the regulator to about 40 psi but regularly get surges up to several hundred psi. This doesn't happen very often and at first I put it down to a dodgy pressure regulator. One is old. The other regulator is brand new. Even the brand new one now though seems to give a surge sometimes, especially when I first t…

Hello everyone, I'm new to this so I'm not quite sure what I am doing, for an experiment I want to connect a Solenoid to a DC Power Supply, to control the strength of the magnet. Before I do is the any safety rules? If you can spare your time teaching me. I'd very much appreciate the time you have taken. Thank you - Jeff

Computer and life form mix has been a general consensus these days. Well you can't really develop a laser from organic life, so why not mix machinery with life?

Looking for a metal that can live in a Aluminium fluoride (AlF3) vapor > 1,290 °C (2,350 °F; 1,560 K) environment , have elongation > 5% better >8% . yield ideally >125,000 Psi. , lifetime > 85 hours . looking for something that will get the job done without "overkill".

Hello My name is Jelle. I'm a belgian 3rd year bachelor student working on a schoolproject. The project consists of a modification of a truck. This modification contains electrical components at 230V AC. The problem is, these electrical components need proper earthing to prevent danger. Normally an earthing is provided but this is quite difficult in a truck because there's no connection with the earth. I know it's possible to use the chassis as a GROUND, but that's just a zero reference voltage so it's not the same as an Earthing connection. My question is: how do I ensure the safety when using 230VAC components that need earthing which is not (or is it?) possi…

Like the one that runs on the lowest amount of power available

I was very recently reading a question regarding the extraction of solvents using negative pressure and why more heat was neccesary. If I’m correct regarding the question, I may have an answer. I’m now a retired mechanical engineer but early in my career I was the chief engineer in two large co-gen processing facilities. I assume that you are using a barometric condenser to establish the vacuum. What can happen is that the vacuum itself will pull more energy than what is required to maintain the lowered boiling point. Hence, more energy is required to maintain the boiling point. If you were dealing with a closed system, this phenomenon wouldn’t be a problem but that…

Good afternoon everyone. There is a surprisingly polarizing debate within the snowmobiling community regarding the final drive ratio of snowmobiles as it relates to size of the lugs on the track. For the non-rider here the tracks have paddles that stick out from the track and they are called lugs. They extend into the snow and provide the traction to move the machine forward. Assume you are on asphalt, will the final drive ratio be affected simply by changing the length/depth of the lug?

I need to make my own smart film for some experiments. https://www.youtube.com/watch?v=LIeXXfDOjjg I've read enough articles on it to know the required components, how they are mixed and applied. I have a 1:1 mixture of liquid crystal and UV curable resin and glass bead spacers that I need to apply between two ITO PETs and UV cure to bond all the layers together. Glass spacers are used to get unform thickness which is needed for uniform opacity/transparency. This will create a "smart film". This is probably done industrially by precision rollers and very powerful UV light to cure it immediately as it leaves the rollers, but I don't have access to such equ…

You thought Nasa would be first, or a company like Deep Space Industries or Planetary Resources? India has been faster, with less resources but with innovative thinking. No scale is given, but it doesn't look small. Without data about how compact the soil is, it's difficult to estimate how much of the opencast mine was usable ore and what proportion landed on the slag heap. Well done!

It's good to have German newspapers, because the French population has known about nothing. On 9th April, 2014, some cooling water leaks in the nuclear power plant in Fessenheim, France. The incident is evaluated at severity 1 over 7. That's what the French citizens have learned of it up to now. Apparently, the people who have known more about didn't even bother to inform the French newspapers: they passed information to the German Süddeutsche Zeitung, definitely more useful. Details about the incident are better known through the request for information sent by the Autorité de Sûreté Nucléaire (ASN) to the electricity producer, Électricité de France (EDF). By the way, …

I wouldn’t attempt this if it was because of the risks associated with high voltage and X-ray radiation but would it be possibly to create a weak X-ray out of a tungsten lightbulb and and an anode on the outside or would the vacuum be too weak/other problems? Please excuse my English and lack of knowledge in the field, it was just a random question.

I am looking for some mirror setup where rotation one or more elements in the mirror setup will allow to shift the beam along its axis. Two mirrors in a galvanometer scanner type setup work well for controlling the angle of the beam. Rotating risley prisms can be used to only offset the beam without changing its angle but the possible positions are limited. Dove prisms are great for rotating the beam along itself or rotate in a circular fashion if prism center is shifted. But as for offsetting (shifting) a beam along its axis from a (-1,-1) position to (1,1) without changing the angle of the beam, I can't find any setup which involves a rotating mirror…

Need to overlay beams by having one replacing the other where they intersect rather than have the beams be superimposed. this is what I want: https://i.imgur.com/F6HIYBl.png this is what I do not want: https://i.imgur.com/ylhMeEa.png This kind of beam combining can be either achieved by the "combiner" OR later in the setup by the "projection screen". Or in other words, having the original beam not reaching the projection surface is not the only solution as somehow not displaying the original beam on the projection surface even if it has reached it will also work. The colors of the beams are for illustration purposes, so are their positions. Position of…

A bit of unsual scenario, I need to divide a video projection beam horizontally into two. Since the splitted beams in my diagram are treated as a separate beam they have to have their focus plane changed. Is that possible to do and how would one do it? http://image.ibb.co/jAu9x7/9241421.jpg If this helps the resolution of the original beam is pretty low by todays standards, 856x480 pixels.