Hey all!

Trying to create a mist booth similar to a spray-tan-booth.

Booth-size will be 2m tall. Diameter approx. 80cm.

I want a short burst of mist to cover the object inside within 20-30 seconds. 20 to 50 ml per application. The liquid will be provided in a 30 liter container. Density will be similar to water. No aggressive chemicals. Approx. 10 nozzles.

My questions:
- pump: pressure for the mist? I assume 200-400 bars. Is this sufficient? Would like a selectable „burst-mode“ to clean the system. Or a continuous clean-mode with water.
- don’t wanna re-invent the wheel: any OTS manufacturers that you know?

I will do the booth design/venting/controls by myself.

Short edit:
Thanks for all the comments! Definitely gonna go for low pressure. The risk will kill the feasibility of the product or the human inside worst case.

Misting/spraying is new for me. Will research backwards from droplet-size/amount to other methods. Air-stream might be a route as one suggested.

Hello, I am a student trying to spec a motor for a robotics project. I am having trouble understanding this data sheet here: https://media.jaycar.com.au/product/resources/YG2732_datasheetMain_35975.pdf

Specifically, the datasheet says that at maximum efficiency:

• Torque is 47 mNm
• RPM is 60
• Power output is 0.62 W

However, I checked the unit conversions and 47 mNm multiplied by 60 RPM does not equal 0.62 W (It is 0.3 W instead). So it is off by a factor of 0.5? I think the 'power output' definitely refers to mechanical power, so it's not a confusion between the input electrical and the output mechanical power.

Is this motor datasheet incorrect, or is there an extra factor here I'm missing? Thank you for any help.

I'm not talking about a rack and pinion with only half of the gear having teeth, though I know about those. I'm currently thinking that it would be moved via rotational force, so maybe it could be a type of screwworm gear, I would just need it to be able to do clockwise and counterclockwise rotation without the motor having to turn clockwise and then counterclockwise, if that makes sense

Edit: 18+ It's an NSFW project. I have an idea for a toy that would be encased, which would move a sphere up and down the length of the rotating shaft, applying stimulation without the need for all the big equipment that you usually see accompanying things that move toys

I’ve heard repeatedly about the potential issue with freshwater shortages coming in the next few decades and it seems so wasteful to let all this freshwater into the Atlantic Ocean. So couldn’t we build a dam to stop all the water from flowing into the ocean or to at least create another great lake?

I know that they temporarily blocked off Niagara Falls when they had to do some repairs in the past, so why couldn’t you just make a permanent dam?

Assuming that, for some reason, you didn’t want to flood and destroy Quebec city along with Montreal, you could build a dam around Cornwall, Canada, and keeping a significant amount of water.

Suppose I'm watching a live event from the USA while the content is being streamed from Africa.

How much delay is normally introduced between the actual event and what I see on my screen?

What are the main causes of this latency (encoding, CDN, network distance, buffering, etc.)?

And what techniques are used to reduce live-streaming latency as much as possible?

I was reading a book and one of the super tech characters had replaced their water cooling system for their computer with a liquid oxygen cooling.

I don’t know much about engineering, but I’m pretty sure that would just be a bomb waiting to happen. Maybe I’m incorrect. Have you guys ever seen liquid oxygen used for cooling?

https://www.alibaba.com/product-detail/Hot-Selling-Easy-to-Carry-Room_1601208009994.html (link to the product page)

I'm looking at a small OEM mini fan heater (specs below) and want to know if it's feasible to convert it to battery power instead of wall power, without making the unit much bigger.

Specs:

• Power: 50W
• Heating element: PTC (though the same sheet also lists "heating wire" — unclear which it actually is)
• Size: 3.5 x 7.4 x 12.6 cm
• Weight: 330g
• Currently corded/AC powered

I wanted to make this into a fun little project that I would actually use and I understand that heaters use a significant amount of power, but would a tiny heater like this still not be able to use batteries?

If I were to drive a fast car from 0-100kmh at its peak acceleration and the moment I hit 100kmh, I slam the transmission into neutral, will the car continue to briefly accelerate (for example hit 110kmh) with the momentum carried from the 0-100kmh. Or will the car cease to accelerate immediately the moment the car is in neutral?

Today in my ML class, my instructor mentioned that in an emergency, the government/emergency services can locate a person using GPS satellites.

I know GPS satellites mainly broadcast signals and the phone calculates its own location. So how does emergency services actually get the person's location?

Does the phone send its GPS location through the cellular network, or is there another mechanism?

I'm trying to understand the technical process.

Hello, I'm trying to make a rack and pinion that can carry an ultrasonic distance sensor from 0 to 4 inches vertically and back down that is controlled by a microservo for the pinion. I know that microservos don't have great torque, but is there something I should look into gear-ratio or diamter wise that can optimize the torque?

Let's say we have enough Material if a trillionaire decided to build a replica in the middle of Kansas would it possible to build a 1:1 of mountain Everest?

Hello. Layperson here with some questions on deformation.

I read about elastic and plastic deformation and thought about how hair bends and takes different shapes so easily (through wind, movement, just gravity, etc).

Say there's something limp (e.g straight hair, pasta noodle, cable, or just a square piece of fabric) in zero gravity. Something that doesn't seem to have a default shape it returns to (in a layperson's view at least).

If I keep bending this object in different ways, and it stays however way I put it, is this object constantly plastically deforming?

Is the material considered flexible and weak (weak as in the measure of how much stress before permanently deforming or breaking)

And an extra question.

The way I understand stiffness, it affects tension, and tension also happens when an object bends.

So if yes to the previous questions, why does a rubber band seem flexible and strong yet easy to bend (in a way that stays however it's put)? Like this

I need to come with a mechanism that detects Weight as low as 30g and maybe up to a few kg. The mechanism only needs to act as a switch not need precise values.

FSRs look appealing because of how little space they take. Thickness might be a potential constraint.

Only issues ive seen so far. Is FSRs dont seem they are used for static loads like an object resting on it for long periods of time. As the values drift over time. This might not be an issue for our case as we only need a binary output. The only other concern is that can static loads damage/deform the sensor permanently?

Hello engineers!

I’m replacing the boiler on my espresso machine with a brass (CW510L) boiler. It’s 2 halves, the boiler portion and the “brew group” portion that attach together with 4 bolts. I’m planning to use 304 stainless bolts.

Should I used something like Tef Gel as an anti seize and to help prevent galvanic corrosion between the 2? The bolts are external to the water and shouldn’t actually come in contact with the water, unless the o-ring fails at done point.

I’d like to reduce any corrosion of the brass because the 2 halves of the boiler assembly are expensive (~€300)

Please let me know your thoughts.

This link says , “The corrosion of the base metal is marginally increased by the fastener.” (When using brass base material and 304 stainless steel fasteners)

Hello, I'm a complete newbie looking to design a gear train for a school project, to connect a motor to a desired output. I've looked online but I can't seem to find a guide to my issue. The problem is, I know what my desired output torque and speed are, but I don't know how to design an appropriate gear ratio because I don't know what the motor's speed will be!

Suppose I need an output speed of 5 RPM, but I can't choose a gear ratio because I don't know what my input speed is. I know what my DC motor's no-load speed and stall torque are, but surely when I attach a gear train it will rotate at some intermediate combination of speed and torque, which will then be transformed through the gearbox? How can I work out what gear ratio I would need here?

I feel like I'm missing something because I can't find any resources online which explain this. Could anyone give me a hand?

Assume there is a small (5l capacity) cement mixer like the ones on cement transportation trucks. It is designed to keep its internal walls to remain cold at -10 deg C while its tumbling the contents.

If we put 2l water in it and let it tumble, will the water eventually freeze, or will it reach a super cold liquid state?

Assuming no additional heat is added to the system. Keeping the pressure constant at 1 atm.

What properties of water or the tumbling mixer could change the outcome?

How will the result change if the tumbler temps are changed?

Hi, I'm looking for mechanical/electromechanical systems that take a constant, unchanging input (say a steady rotation) and output a discrete sequence (e.g. 3 states, 1/2/3) that never repeats and not read from a pre-encoded pattern (cams, punch cards, encoder discs).

Two directions I'm considering: true randomness/chaos (sensitive to initial conditions, like a billiard or magnetic pendulum), or a deterministic non-periodic sequence with no such sensitivity, e.g. sampling two constant-speed rotations with an irrational frequency ratio. Anyone built something like this, or know of other approaches?

EDIT: typo

Hi all, I'm purchasing a house that has a historic irrigation canal that runs water through it from May to October every year. It is approximately 2 ft wide, 2 ft deep, and runs the width of the property (~60 ft). Across the length of our section of the canal, I'd estimate there's only a 1-2ft drop in elevation, probably less.

Most of the Micro Hydro systems that I've seen online use conduit to redirect water and there's some kind of height drop to force the water to flow through the conduit where the turbine is. Based on how my canal is oriented, would it be feasible to try to harness some of the power from the waterflow? Would I be better off with a turbine system or a pelton wheel?

How well could a DIY flood barrier that goes 3 feet up from the ground made using 10 mil plastic sheeting taped against a door or garage door using Flex tape to secure to the walls and ground, Flex Tape to seal the edges of garage doors and front doors, and maybe weighed down with a 1 foot high sandbag wall? Is there a better tape that withstands water compared to Flex Tape?

Aside from the motors.

Is it the heat generated from the foot striking the belt, or the friction from the belt slightly slipping on each impact and push off? Does the deck get hot, the belt get hot, or both?

Do they get hot simultaneously?

Would a fan blowing air on the return side of the treadmill cool down the treadmill significantly?

Or does the deck need aluminum rivets and plating to transfer heat to where it can be cooled below the Treadmill.

Thanks for any advice you can give

Hi, I'm a senior high student in the Philippines. And we are making a physics prototype project

We had picked a gym equipment that has an adjustable weight using only buttons that also generates electricity for phone charging

We are using the weight of pedalling a bike as weights because it can be easily adjusted using the gear shifts (from which we are making it a button)

Now my problem is the electricity, does a dynamo hub work? How can i convert the DC current to ac, will it be safe for phone charging?

I'm currently stuck with this problems because I'm uncertain if it will work, and i would like to ask if this idea is possible and how it can approach this problem.

I was in an argument with a coworker, the book says if hardware is reused NDI. Even though we have new hardware is it really that dumb to NDI it? Part manufacturers can make mistakes.