# All Questions

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25k 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....
238 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 ...
134 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 ...
156 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 ...
173 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 ...
1k 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?...
6k 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 ...
4k 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 ...
557 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 ...
217 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 ...
5k 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?
343 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 ...
129 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 ...
83 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. ...
838 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 ...
667 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 ...
3k 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 ...
9k 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 ...
4k 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 ...
238 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 ...
178 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 ...
1k views

### Why are hyperboloid towers not popular anymore?

Hyperboloid towers were very popular in the end of 19th and the first half of 20th centuries - water towers, powerline anchor towers, sometimes tall radio towers were built using this design. The ...
6k views

### How do you attach something temporary to a smooth metal shaft?

I want to attach something small to the smooth metal shaft of a small motor (2-3 mm in diameter), like fan blades, but I want it to be temporary. If I make it too loose, then the fan won't turn at ...
114 views

### Can the production rate of labs-on-a-chip ever reach the production rate of silicon chips?

Labs-on-a-chip and silicon chips both have the potential - and in some cases have already reached the potential - to drastically scale down tasks, in these cases performing chemical reactions and ...
705 views

### Creating smooth shaft resistance

I am trying to emulate the resistance of a hand wheel which moves a table via a series of shafts and chains which turn an acme screw. I am switching to a CNC system that will allow the user to keep ...
975 views

### Mounting and Coupling an Encoder

I was wondering how to mount a small rotary encoder to a platform in order to measure how far a small treaded robot has traveled. We're using this tread/wheel set: We've tried epoxying the encoder ...
822 views

### Meshing of complex geometrical domains

When using the finite element method, I have always used either already meshed domains or very simple ones. From what I've heard, meshing complex geometries is often outsourced to specialized ...
542 views

### Possible Hazards of Software Controlled Systems (Ex. Airline GPS/Elevator)?

I am currently reading through a book on Software Engineering principles, with a lot of the content having to do with proper approaches to software development methodologies and project management ...
1k views

### How many units of HB are used for steel bridges?

Bridges in the UK can be assessed (to standard BA34/90) using an HB vehicle (to standard BD37/01). The HB vehicle is 16 wheel loads, each of 2.5kN times "units". For concrete bridges the number of ...
18k views

### How fast does solid waste fall in vertical drain pipes?

Some building are really tall, if you flush the toilet and the contents go into a pipe and straight down, there could be a lot of energy, potentially enough to cause harm to the sewer pipe at the end ...
1k views

### Soil swelling and mass/volume relationships

Given moisture content, Specific gravity of solids, initial volume, and weight. I'm asked to compute the moist unit weight, dry unit weight, and degree of saturation of this compacted soil. This is ...
1k views

### How do I form a budget for a mechanical research project?

I'm a mechatronics engineering student currently on workplacement. I've put forward a research proposal to develop an improved mechanical gripper used for automated product handling. The company likes ...
5k views

### What makes suspension bridges unsuitable for railways?

I recall reading in an old issue of Model Railroader an article about railroad bridges. In it, the author mentioned that you shouldn't have a model suspension bridge for a railroad track on your ...
207 views

### Cutting mechanism for a robot in confined spaces

I'd like to build an exploratory robot that can fit within confined spaces1. As the robot moves along the inside of a 4" pipe, it's likely to encounter some obstacles that need to be removed. ...
335 views

### Final speed of a truck on a slope?

I have a truck which weighs 190 kg and will travel 100m down a 38° slope. How I can find the trucks speed at the end of the 100m?
108 views

### Traction mechanisms for a robot in confined spaces

I'd like to build an exploratory robot that can fit within confined spaces1. What traction mechanisms should I consider to propel a robot along the inside of a 4" pipe? The pipe to be traversed will ...
8k views

### How to make smoke for a small wind tunnel?

I am making a small (desktop) wind tunnel for educational purposes, I want to have 10 fairly thick smoke-streams about 3cm apart. I have experimented with incense but the stream is not thick enough ...
95 views

### What is the name of the part that allows a steam wand to have a moveable joint?

On espresso machines, there is some kind of pipe joint which allows the steam wand to move while maintaining its seal. What is this component called?
248 views

### Controlling hydraulic cylinders with variable delay

Electro-mechanical systems typically used in robots have very low delays and are quite simple to build servo controllers for. Hydraulic systems are much less common in robotics and have delay due to ...
723 views

### What is the focal distance of an optical mouse?

I am trying to build an optical sensor for my old school, state property, standard french watt-o-meter. EDF ( Electricité de France ) has a gig which turns a wheel depending on watt consumption. The ...
2k views

### What are the longitudal tolerances of thread on metric nuts and bolts?

It's not exactly my area of expertize and I've spent a couple hours ears deep in norms, and I'm not really sure if what I found is correct (the figure I found was to the order of 1$\mu$m). When using ...
2k views

### What are the major differences between Engineering degrees and Engineering Technology degrees in terms of employability?

What difference in education occurs between two graduates, one with an Engineering Technology degree (be it Civil, Mechanical, Electrical...) and the other with the equivalent Engineering degree "...