# All Questions

10,138 questions
Filter by
Sorted by
Tagged with
2k views

### What is the unbraced length of a pile in soil?

When analyzing a pile or drilled shaft as a beam-column, how do you determine the unbraced length of the portion that is in the ground? Typically, the braced points on a beam or column are well ...
4k views

### Do structural engineers carry insurance for catastrophic errors?

A friend of mine is a structural engineer and he often complains to me about how little sleep he gets at night worrying over whether or not he accounted for all the little details involved in his ...
737 views

### Can superhydrophobic surfaces be used to reduce drag?

I am mainly interested in reducing drag in aircraft and I have an idea that I want to learn more about... Can a superhydrophobic coating reduce drag in water-craft such as boats and submarines? If ...
2k views

### What is an engineer's liability for code changes that occur after submitting a design?

What if any liability would an engineer have in the following situation? This is specifically in reference to engineering within the USA. An engineer produces a design and plans that meet the ...
340 views

### Modern method for teaching controls

Background When I took my first class in controls (2006-ish as taught by an aerospace professor for a mix of ME and EE students) it was basically all done in Laplace-transform, transfer functions etc. ...
356 views

### Estimating whether the flow through a valve or nozzle cavitates

My understanding is that cavitation occurs in the flow of a liquid when the static pressure drops below the vapor pressure, even intermittently. So even if the time-averaged static pressure (what you ...
7k views

### Finding the pull-through capacity of a nutted bolt and washer in ASA plastic

I have a uniform load applied to the underside of a plastic sheet which is to be resisted by the combination of a bolt, washer, and nut as depicted below (the other end of the bolt is secured and will ...
6k views

15k views

### What is the purpose of these diversions in a natural gas line?

The campus where I work has a long covered walkway (~.5 mile) which has several labeled pipes running under the roof (chilled water, fuel oil, air...). All of the pipes run dead straight except for ...
7k views

### How does a multimeter protect itself from high voltages?

I have used a cheap multimeter to measure voltages in simple DC circuits, but I have seen pictures of them plugged straight into the mains and used to measure various home-built generators. Why doesn'...
16k views

### Does a transformer use power when output isn't under load?

I was reading about how AC to DC converters work with a step-down transformer and then a diode bridge to convert the lower, stepped down AC voltage into DC. What I don't understand is since the input ...
28k views

### What kind of math do engineers really use? [closed]

I am from the mathematics StackExchange section, many of my students are engineering students at University. I was wondering what kind of calculus do you real engineers use? I have known two engineers....
253 views

### Motor Driver board: limited current

I'm having some trouble using a motor driver board. I'm pretty sure its being driven properly since there is ~3V @ the output v.s. none when its off. However it should be supplying ~2A (rectifier ...
135 views

I'm a bit confused about all the different "definitions" of uncertainty? One can calculate "uncertainty" of a single measurement by simply checking how accurate the tool that is being used to do the ...
165 views

### Scale models of thermal plumes

I want to look at the thermal heat plume of a human in still air in a room. So I have a tank of water with a heating coil/cylinder in it. How do I calculate what the heat output of my heating coil ...
183 views

### How to divert solids from a downward vertical pipe

I am an electronics engineer trying to build one small underwater mechanical device (about 12 cubic cm) as part of a personal automation project. I have figured out the electronics for this, but I am ...
2k views

### How to design electronics to mitigate tin whiskers?

Tin Whiskers are a major problem in the design of electronic circuits and the manufacturing of electronic hardware. What are Tin Whiskers? How can electronic products be design to mitigate the issue ...
2k views

### What is the practical limit on the number of storeys in residential buildings built with monolithic reinforced concrete?

I have recently bought a flat in a 25-storey building. I wonder what is the practical limit for the number of storeys in a mass-produced residential buildings built from monolithic reinforced concrete?...
7k views

### What is a reason that handlebars fit to a motorcycle and steering wheel fit to a car?

What is the reason that handlebars are installed on motorcycles and steering wheels are installed on cars? Notice that the way to use both handlebars and steering wheels are quite similar, but a ...
5k views

### Is it acceptable to paint weathering steel?

Weathering steel is not typically painted, because it produces a thin rust layer that protects the rest of the steel from further corrosion. Would painting weathering steel be an acceptable additional ...
597 views

### Thoriated tungsten TIG electrodes were in use 45 years ago.What were their specific use and problems?

Some TIG electrodes in use in the early 1970's were marked Thoriated Tungsten and Non-Thoriated Tungsten. What were the specific purposes or properties for these TIG welding electrodes?
1k views

### Are standard structural bolts acceptable for all cold climates?

The specifications for standard (ASTM A 325) bolts do not list minimum service temperatures. I am thinking of outdoor applications like Alaska or Canada (lows of -60F) and wondering if the cold ...
223 views

### Best traffic control device/system for given situation

I am familiar with the round-a-bout/traffic light pros and cons, however, I've been tasked with deciding on a solution for the given parameters below. Currently, there is a two-way (four lane) road ...
6k views

### Why is it unwise to choose cylindrical horizontal beam

I heard that it is unwise to choose cylindrical horizontal beam. My question is why?
349 views

### What type of sensing element is used in Water Quality Monitoring Meters?

What type of sensing element is used in Water Quality Monitoring meters such as those pictured below? I might not be using the correct search terms. Some of these meters monitor Total Dissolved ...
1k views

### Tankless air compressor for electronics desoldering station

I purchased a Weller WSD161V soldering station (similar to this one, at least with regards to the pneumatic system I'm about to describe -- sorry, I was unable to find a manual for my specific model ...
132 views

### Is making a toilet flush backwards problematic? [closed]

The Coriolis effect impacts the way water tends to circle before going down the drain. Many (most, all?) toilets are designed to work with the Coriolis effect. I am considering a line of toilets ...
95 views

### Where to insulate Underfloor air distribution system in a temperate climate

I have a proposed underfloor air distribution system (UFAD) for a one level office in a temperate climate. Typically the demand for heating and cooling in this climate is about even for offices. ...
924 views

### Could air-launched space planes reach escape velocities?

Rockets like the Ariane 5 weigh hundreds of tons, but with about 85% of that weight being fuel, the payload fraction is only about 3% (~10-20 tons). Virgin Galactic is building suborbital space ...
684 views

### Can you get quality welds from a multiple metal wire feed welder, or do you need separate units for steel and aluminum?

The job site requires welding both aluminum and steel (each to themselves only) for different areas of the project. The contractor has a dual purpose wire feed welder (aluminum and steel) but I am ...
1k views

### What is the densest ceramic?

I know ceramics are generally considerably less dense than pure metals or alloys but sand is used in barbells for its probably cheapness, user-friendly and easy availability but its a decent density ...
4k views

### Measuring longer distances with high accuracy

I am involved right now in the fabrication of steel structures on the order of 5-50 feet long. Presently, we measure these structures with garden variety commercial tape measures. Most of the time, we ...
1k views

### Motor for a hydraulic pump in a hydraulic system

I am a complete beginner to hydraulic systems, and I've wanted to learn more about this area. I'm designing a hydraulic system that involves using hydraulics to push/pull objects using pistons. I have ...
11k views

### How do I manufacture a fillet?

What are the most popular and the most efficient ways to machine a fillet on an external edge of an object? If I were to use a CNC mill, what tools can I use for it, and how would the method change ...
5k views

### What bolts should I specify with Weathering Steel?

When using weathering steel (COR-TEN) on a project, what sort of bolts should I be using? I have yet to see fixings made of weather steel; presumably because the way it uses a sacrificial layer to ...
256 views

### Ensuring even flow in liquid pumping in distribution circuit under suction

I have a liquid circuit which looks a bit like that: The system is under suction, and the flow rate through each unit should be about 10ml/min. However, we noticed that unit ...
2k views

### Could a gold/{second metal} crown be created that would pass the Archimedes test cost effectively?

Many people are familiar with the story of Archimedes submerging a crown in water to identify if the volume of the crown was consistent with the volume of the same amount of gold. The test was to see ...
181 views

### Name of spring actuated component

I need to get another component like this but I can't seem to find any manufacturers / retailers. To describe it: It is spring mounted on a shaft and retained by bushing on the top and an enlarged ...