8 votes
Accepted

Cooling tower for nuclear power plants

The hyperbolic shape of cooling tower is preferred as this shape is stronger against wind pressure. Consequently, the concrete wall thickness can be reduced and optimised. from 1.5m at the base of the ...
Vincent's user avatar
  • 96
5 votes

Tower crane with a cabin on ground level

The crane operator at the top of the tower doesn't just have a view of the load being lifted. He/she can see the entire surrounding area and take account of any potential hazardous situations that ...
alephzero's user avatar
  • 12.5k
4 votes

How would you move a sail boat with no wind or paddles

The answer, despite what several responders think, is unequivocally YES . However, you will get more efficient propulsion just by blowing directly backwards. All a sail does is deflect wind, thus ...
Carl Witthoft's user avatar
4 votes

Why don't we make bricks out of coffee grounds?

Bricks are primarily made of sand and clay. The sand acts as a filler, and clay is a substance that has some rather remarkable qualities. Coffee grounds do not exhibit the qualities of sand or clay. ...
David Hammen's user avatar
4 votes

What does this equation mean?

The $\propto$ symbol represents proportionality. So, whatever is on the left hand side is directly proportional to cross-sectional area and inversely proportional to volume. Now, as to the actual ...
Wasabi's user avatar
  • 13.1k
4 votes

What is the most efficient way to ionize air?

It will depend on the degree of ionization you require, as well as the pressure of the air passing through the ionization region. Your gas will not likely be at STP if the air is moving through a ...
phyllis diller's user avatar
4 votes

Is a single large impact better than several small impacts for breaking ice

Multiple smaller, light impacts are better. The heavy concentrated impact can damage and crack the already fragile pavement which has likely lost most of its resilience due to the freezing ...
kamran's user avatar
  • 22.2k
4 votes

can ceramic be used as a building material?

structural ceramic does have some applications in things like engine parts, but its cost and manufacturing difficulty makes it a less ideal choice for something as large as a building foundation The ...
Mohammad Athar's user avatar
4 votes

can ceramic be used as a building material?

One of the foundational principles of structural engineering is obviously safety. And one of the foundational aspects of safety is the ability to show warning signs prior to any accidents. In the case ...
Wasabi's user avatar
  • 13.1k
3 votes

Controlled demolition of a sky scraper?

It is certainly possible, although far from easy and requires very specialist knowledge. First the building will be surveyed in great detail to determine how the loads are carried throughout the ...
Chris Johns's user avatar
  • 15.2k
3 votes

Tower crane with a cabin on ground level

It is not trivial to replace human vision with a camera in this sort of situation. it is difficult to reproduce good depth perception with cameras the human eye can change focus quickly and ...
Chris Johns's user avatar
  • 15.2k
3 votes

Can a neutrally bouyant helium balloon be suspended in air using magnet entrapment?

Could the top floating peace be place inside a helium balloon buoyantly neutral and stay entrapped in the magnetic field without having to spin? No. The system relies on the gyroscopic stabilization ...
Jonathan R Swift's user avatar
3 votes

Ventilation setup high sleeper night cooling

I would recommend a modification Phil's answer: airflow is almost always better when the fan is exhausting to the outside - fans don't "like" back pressure and work most efficiently when dumping to an ...
Carl Witthoft's user avatar
3 votes

What are the limits on building very high buildings using certain materials and architectural style?

The tallest masonry building erected is the Philadelphia City Hall . It is 548 feet high. The issue with building masonry structures is the walls have to support the weight of the building and the ...
Fred's user avatar
  • 9,667
3 votes

Cooling tower for nuclear power plants

The shape is to take advantage of the Bernoulli law. The narrower throat of the tower creates reduced pressure encouraging faster convection discharge of warm, moist vapors. Hot water from the ...
kamran's user avatar
  • 22.2k
3 votes
Accepted

Can a horizontal foundation safeguard against earthquakes?

Things topple when their center of mass moves past their supports. Think of a square box: if you push it over slightly and let go, it'll fall back onto its original position. But if you push it past ...
Wasabi's user avatar
  • 13.1k
3 votes
Accepted

Is it just surface area alone that causes bridges to freeze?

Heat is the transfer of energy from a hotter region to a cooler region. The surface in contact with the earth enjoys the benefit of conductive heating. Being cooler, the energy of the warmer earth ...
fred_dot_u's user avatar
  • 7,055
3 votes

Why did they move ancient Egyptian temples to prevent them from water damage instead of encircling them with a dam?

Shielding them by a dam would have been more costly. And being hidden under a 65 meters deep wall into the water of the Aswan dam would make them visually disappear, and lose their glory. As it is now ...
kamran's user avatar
  • 22.2k
3 votes
Accepted

Would a larger building more safely or smoothly ride the seismic waves of an earthquake?

Earthquake waves are very long. For example in California, the frequency of the 1996 Northridge earthquake was 0.5Hertz. This shock could cross the diameter of the earth in half an hour (Not correct! ...
kamran's user avatar
  • 22.2k
2 votes

Tower crane with a cabin on ground level

From 1924 to 1932 Sydney Harbour Bridge was constructed. It used two creeper cranes on both sides of the arch during construction to hoist people & materials. The crane operators couldn't see ...
Fred's user avatar
  • 9,667
2 votes
Accepted

Recreating Focaults Pendulum

There are two simple options for the bearing The first is to suspend the bob from a flexible cord passing through a fairly tight grommet so it will maintain a constant point of contact in all ...
Chris Johns's user avatar
  • 15.2k
2 votes
Accepted

Rubber band Powered Free Flight Helicopter

Yes, even through a simple parallelization of a single-rotor design. If there's no other payload than the helicopter itself, and the challenge is for staying airborne, you gain about nothing ...
SF.'s user avatar
  • 6,135
2 votes

How to make a pulley system with a mechanical advantage of 0.5

What you need is a block-and-tackle, namely a gun-tackle. Source The general trick to determine advantage is how many verticals you have bearing the load (other than the end you are pulling from). ...
Wasabi's user avatar
  • 13.1k
2 votes
Accepted

Does attic insulation help cool a building?

Attics are much hotter than the outside air when the sun is shining on them (say 120F in an attic). When the air conditioning system is running the internal air temperature is less than the outside (...
ericnutsch's user avatar
  • 8,136
2 votes

Does attic insulation help cool a building?

in the summer, the outside of the house- especially its roof- is hotter than the inside of the house. In this case, attic insulation does not physically "cool" the house- it just impedes heat transfer ...
niels nielsen's user avatar
2 votes
Accepted

Place a greenhouse: how to orient it for the best effect?

In general: if you are in the northern hemisphere, the sun will pass through the southern part of the sky. Therefore, a greenhouse which is built onto the side of an existing structure will be placed ...
niels nielsen's user avatar
2 votes
Accepted

How do we define the durability as per density?

This is clearly building on this question, and specifically its accepted answer. Not to toot my own horn, but I recommend you also read my answer to that question. More specifically, the first ...
Wasabi's user avatar
  • 13.1k
2 votes
Accepted

What does this equation mean?

I suppose your statement is correct. If $$\text{Cross-Sectional Area}\times \text{Length} = \text{Volume}$$ then, $$x\propto \frac{\text{Cross-Sectional Area}}{\text{Cross-Sectional Area}\times \...
smollma's user avatar
  • 307
2 votes

How would you move a sail boat with no wind or paddles

I've done a lot of sailing (won a couple national championships) and the answer is yes. But you wouldn't want the fan blowing forward from the stern. Instead you would want it blowing towards the ...
Parker Shinn's user avatar
2 votes

Ventilation setup high sleeper night cooling

Air hates to flow into corners, even if there is a fan. A thermally stratified box is about the most obstinate thing there is to make comfortable. The best solution would be to run a small duct ...
Phil Sweet's user avatar
  • 4,696

Only top scored, non community-wiki answers of a minimum length are eligible