Engineering

Hello, I'm really interested in fuel cell cars and working on a school project related to them. I went quickly through the options the car manufacturers have these days when constructing a FCV and I cannot understand why all the models produced right now are equipped with very similiar technology. All 3 of them have a PEM fuel cell in combination with a hydrogen tank and I'm wondering, why would't they go with a PEM fuell cell, methanol tank and methanol reformer? The methanol as a fuel has a lot of advantages compared to hydrogen. So what I'm thinking is: A) the system would be more expensive B) the system would weigh more I think the combination of PEMF…

Hello guys. I have an engineering project I've been working on for quite some time now. It's a large hybrid rocket that I plan to build, and I expect it to cost around 2-3k. Now, because it costs so much, I plan to build it over the course of a few years. But at the same time, I really don't want to waste money so I'd like some tips. So, I'll explain it now. Firstly, it's objective. The objective is to get it to around 1k meters, and then bring it in for a propulsive landing. I know landing it will be extremely hard, but that's more of an afterthought. For comparison, my highest rocket got to about 1800 feet, but that was for a…

Do I understand it correctly, that if outside temperature is -20 C and we intend to heat premises to +20 C, using heat pump solely, the maximum theoretical efficiency going to be around 700%? https://www.engineeringtoolbox.com/heat-pump-efficiency-ratings-d_1117.html If yes, then why heat pump practical efficiencies are still much lower than theoretical values? What is the issues with technologies? Why Otto or Diesel engines work much closer to theoretical values than heat pumps? Also, how practical would be air-air heat pumps designed for apartments in buildings where use of ground waters is hardly an option? What would be their size and cost at temperatur…

Hello, I need help with the Charpy Sheep Resilience Test Bench using ASME ur (US standard) I found some French standard but unfortunately it pays . example: NF A03-508 and ISO / R442. I want to emphasize especially the components of the test bench justifying the norm. Thank you in advance for your collaboration,

Could someone possibly elaborate on the possibility of using very many 'smaller' batteries on telephones, laptops etc, assembled as one package off course, than using one, as they do now. Charging them in parallel they would recharge in a minute then using them appropriately to feed the circuit, like in series for example.

Can anyone tell me where I can get a furnace that can produce temperatures up to 1700 degrees Celsius for melting metals.

When new sources of energy are being proposed there is often an impetus to subsidize them. Currently we have a lot of wind farms being subsidized. I am of the opinion that this is pure theatre and self delusion. If the energy source cannot survive without subsidy then it is clearly not producing more energy that it consumes. This discussion often gets bogged down when people try to redefine the word 'subsidy' and include things like tax rebates in the definition. So I will use a definition here - a subsidy is a net flow of energy into a system from outside. I will also add that as a corollary to this the Cost of something is a very good measure of the…

Hi all. Need to bounce ideas for a project at work. I would like to dissolve hydrogen gas (among other gasses) into a closed loop system of mineral oil. With Henry's law, I can lower the temperature and increase the pressure to help. But if I don't help dissolve it along via pressure and temperature manipulation, the gas will just sit on top on not mix right? If this closed loop has a pump to circulate the oil, will that be enough agitation to help dissolve the gasses? Also, how would I calculate the new concentration? The gas has a given ppm sent by the manufacturer, and the oil has a certain volume based on the container I choose. Is it just some simple math? …

Hi, Recently I was faced with a challenge to find out how long it might take for moisture concentration to reduce from 80% to 30% for soil, under constant sifting/turning . Here is the cenario. I have a tunnel of 80 meters, width of 4 meters. depth of 2 meters. daily, wet soil will be delivered to the front end of the tunnel and everyday, or given a set period there is a machine that mulch/mix and flips the soil backwards by 1 meter. The constants are: Input soil: 10 cubic meters, 80% water content. Machine: has blade that mixes the soil and flip it backwards by 1 meter. The bed of the tunnel is heated to 50 deg c, can assume the en…

The Moon's gravitational attraction of is responsible for tide. The amount of force required to move oceans is incredible relative to our (humans) our energy producing ability. At present there are attempts to harvest wave energy but none appear scalable to level which could be used to power large portions of industry of cities. That said the energy potential seems self evident. To my knowledge Nova Scotia is one of the leaders on this front. However most systems I am aware of focus on using swells to move magnetics https://energy.novascotia.ca/renewables/marine-renewable-energy/top-10-things-tidal-energy Are there other ways to harness the Moon's Gravita…

The Moon's gravitational attraction of is responsible for tide. The amount of force required to move oceans is incredible relative to our (humans) our energy producing ability. At present there are attempts to harvest wave energy but none appear scalable to level which could be used to power large portions of industry of cities. That said the energy potential seems self evident. To my knowledge Nova Scotia is one of the leaders on this front. However most systems I am aware of focus on using swells to move magnetics https://energy.novascotia.ca/renewables/marine-renewable-energy/top-10-things-tidal-energy Are there other ways to harness the Moon's Gravita…

In this hypothetical questions, let's assume the infrastructure and automotive industry is well suited to run on ethanol fuel. Would a vertical farm, off shore much like oil rigs, be the best way to cultivate corn or even switchgrass? Think of a 70-story building, 3 acres per floor. All water is provided at the source. Crops could be genetically engineered in a way that you'd obtain the highest yield, and the genetic modification wouldn't harm people as it wouldn't be consumed. Picture as many vertical farms as there are oil rigs. Why not in the future, convert the oil rigs into vertical farms? ~EE

Not sure if this should be under the chemistry section. How/where does a two way catalytic converter get oxygen to perform the oxidation of hc and co ? Is it from the rich lean switch of ICE air/fuel ratio ? Did a bit more research, the combustion gas has left over oxygen that the two way catalyst uses to oxidise the hc and co. I think I am good.

Hello, everyone, ... So, i've got a simple question, which career do you think is the best for an engineer after graduation: pursuing academia and becoming a professor, or going to industry and becoming an Engineering Manager ? what are some pros and cons of each one ? thanks a lot in advance for your answers.

I don't like floor to ceiling windows, because i never feel they are very safe. what if they are broken and fell down ? so i ask these Qs. there was an accident. (CNN) -- One woman was killed and another injured after they fell from a 10th-floor window at an Atlanta hotel, authorities said Saturday.According to Atlanta Police, witnesses said the two were attending a birthday party early Saturday at the W Atlanta-Midtown. The pair were "play fighting" when they accidentally crashed through the window around 3:15 a.m., according to a preliminary investigation, said department spokesman Officer John Chafee. It was unclear Saturday where they landed. http://edition…

Why IP telephony haven't become a landline communication standard yet? Some people say this is because Internet is less reliable than phone. But why is it less reliable if exactly the same hardware is used for signal transmission? If hardware is different, where exactly the difference is?

Just finished a great documentary on the Millau Viaduct in France, and it inspired me to create this thread about the biggest, baddest bridge near you. Know idea why, but bridges have always fascinated me. Even when I was a kid, I would stare out of the car window as we crossed rivers and gorges, awestruck at this road in the sky and how it was created. Here in South Carolina, the baddest bridge is the Arthur Ravenel Jr. Bridge about 75 miles away from me in Charleston. The cable-stayed bridge has a main span of 1,546 feet (471 m), (total length is 13,200 feet) and is the third longest among cable-stayed bridges in the Western Hemisphere. More bad a** …

I have two identical containers with vents at the bottom of each container, a tube connecting them at the top and each container filled half way with water, both are located in a larger tank of water. Question is: - If i press down on one of the containers forcing more water into the bottom of the container, will the air transfer to the other container via the connecting tube and force out the water in the second container?

I read that wood glue is supposed to bond better than wood, which didn't jive with my physical intuition. I did some stress testing with various types of wood, and here are my results!

I’m looking for some advice. For weeks at a time, I’ll be woken up once or twice a night. Sometimes I can lay in bed and at the same times I usually wake up I’ll feel an odd sensation of pressure in my head. Two successive housemates have felt the same thing. They’ve described it as a clicking, pinching, snapping or pressure sensation that lasts just a split second. It’s not painful, but its enough to wake us apparently. A while back I spotted tracks in the snow in a neighbors back yard. So, I approached that neighbor. He refused to install security lighting, or cameras, and just dismissed my reports. I was able to pay another neighbor to let me set…

Does Ballistic Capture mean solar engine ships can efficiently bring cargo to Mars? Since Mars gets about half the solar energy the earth does, braking near Mars is that much harder for solar powered spacecraft. Also, Ballistic Capture allows a continuous stream of cargo to be sent, keeping the solar ships continuously operating, no need to wait for that window only open every ~26 month. Return trip doesn't carry as much cargo, so the efficiency lost due to lack of solar energy is reduced. Thoughts?

Maaany years ago read about a figure that made sense to me... The delta t from a internal combustion engine related to the ambient temperature its cooling radiator was exposed. Cannot remember now. Was something like outlet temperature minus ambient temperature equals something near constant. Or ambient temperature plus inlet temperature equals a near constant figure. That ideal figure escapes me now... Any light or explanatory link please ?

Hi, I need to some kind of sensors/tags which can be placed outdoor. The same needs to be read from about 25 m. (There will be need of setting multiple sensors in proximity, so the reader had to be a pin point and accurate system.) On reading it should open particular pdf file on computer.

I'm currently creating a theoretical space habitat that would resemble a collection of Torus rings. Now, to keep them away from each other, I'm attaching them by 7 poles of 2219 aluminum on each ring to a motor that rotates them for artificial gravity and slight position adjustments. Now, I still need to do the trig, but I'm wondering if these poles will become stressed by rotations and if they can could withstand losing a pole. I'll get the trig on a soon as possible.

I want to engineer a room that has electromagnetic tiles on the floor and the surface of these tiles would be polarized south. i also want to create a suit that has various magnetic metals on the suit placed in specific anatomical positions and the surface of these metals would be polarized north. if calibrated correctly this could be used in space to pull down the person in the suit and allow the user to walk freely in a spacecraft. this would cause the person to use their muscles more often and the bones would have pressure on them. I believe this would either slow down or halt the process of bone and muscle loss. it isnt a complete solution but its a new approach to so…