# All Questions

8,536 questions
Filter by
Sorted by
Tagged with
881 views

### Why oil is used as lubricant in hydro, wind power generators, while water is the most available, cheapest and accessible lubricant?

The lower viscosity of water, reduces the friction, besides the water can transfer heat way better than oils, so why not using the water as a lubricant in wind or hydro turbines, specially on those ...
4 views

### What object characteristics may cause significant distance measurement deviations in Sharp optical sensors?

Not sure if this is the right place to ask this question, but anyways. I'm not very fond of circuits and stuff, but I've got a test question I really need to answer. The question is in the title, ...
74 views

### Not solvable question civil engineering

They didn’t give me the radius of the wheel where external force F is acting . How can I calculate the reactions at A,B . When they didn’t give me the radius . Is this question “ Wrong “ ? Note ...
6 views

### Thermal radiation measurements: Looking for ~100 Hz BW, broadband (1-20 um) NIR/MIR detector

I am looking for a detector with about 100 Hz bandwidth, that has broad and ideally uniform absorbtance in the 1-20 um range. I need to be able to pickup signals in the 1 uW range with SNR >10, ...
7 views

### Name of this type of platform lift

There's a simple way to lift a platform a short distance: Identical discs are mounted on a frame at the four corners of a platform such that front pair of discs' axes of rotation are colinear, as are ...
24 views

### Where do I get basic mechanical components?

I'm looking for a few basic devices such as converting translational to rotational motion, 20:1 gearbox, etc. Found nothing at Home Depot. Could you suggest where does one buys/orders such components?
35 views

### installing swing hook before concrete is poured

I want to place a swing hooks in place before the concrete is poured so that , i dont have to drill a hole later. My contractor is not ready to make these bolts with TMT bars itself.. what kind of ...
66 views

### How to analyze a bent beam: Stress concentration?

I am analyzing a beam, that has a bend in it. Intuitively and inspecting FEA results using a linear solver, there is a stress concentration at the bend of this I-beam. When I was learning about ...
38 views

### Is there a standard for where treelines are drawn?

On surveys and site plans, I've often found treelines. These look like the below image, and serve to delineate in a very approximate way the areas full of trees and those that aren't: Is there a ...
19 views

### Turn rate of a jet vs. biplane

A friend and I were debating whether a biplane/propeller plane has a faster turning rate than jet aircraft. I argued that the propeller planes often do have better turning rates than jets, but I could ...
16 views

### What is the mathematical basis for the Ziegler-Nichols method for tuning a PID loop?

The Ziegler-Nichols method of tuning PID control loops has been around since the 1940's, and has been widely applied in many areas of engineering. I understand that it is really only a heuristic ...
9 views

### How can I model a hysteresis curve from data?

I have the task of modeling the current to torque mapping for a given motor. I have an experimental set up where I can retrieve current, torque pairs. Now my initial approach was to model the ...
14 views

### Using RC scale-down model to pre-test aircraft design

I'm a bit involved into building an actual airplane. And while the guys go conventional ways, I'm trying to look around to see other solutions. One of that is to try and use and RC scale-down model (...
31 views

### What is the mechanism of adsorption-desorption on biochar obtained from slow pyrolysis/ torrefaction?

Biochar is a major by-product from pyrolysis along with bio-oil and it is considered an important chemical feed-stock because of many light oxygenates. I have read some papers on using bio-char use ...
40 views

### Simple steel column buckling calc - where am I going wrong? (Eurocode)

I'm trying to follow an example of this, but I get a wildly different answer than expected and I can't see where I'm going wrong. The example I've got, is for a 2.8 m steel column (RHS 150 x 100 x ...
27 views

### how does this z-axis micro-adjust lead-screw design work

The picture (which I found on the web without any accompanying explanatory text) shows a home-made z-axis micro-adjust lead-screw add-on to the vertical milling attachment of a vintage hobbyist lathe. ...
53 views

### Can magnetic stripes be read wirelessly with lasers or other technologies?

I know that magnetic stripes used in credit cards and audio tapes are typically read by a magnetic reader head. But is it theoretically possible for the stripe to be read by a laser in a similar ...
40 views

### How fast could a Mini Cooper go in a vacuum?

Lord Evulz just stole the Earth's atmosphere. Our hero must race his trusty old Mini - which he had already prepared to be airtight, to ensure the tires do not explode, with pre-packaged oxygen to ...
19 views

### Transfer function for a quadcopter with linear velocity inputs

I found the control for a quadcopter using the angular velocities or thrust power as the input, but I need a model where I can set the initial and final position (for example, from (0,0,1) to (0,1,1))....
13 views

### What would be the surface area of a boiler that has a heat input of 850 MW from combustion? [on hold]

The rate at which heat is supplied the boiler is 850MW which is attained by burning 20Kg/s of natural gas. Heat losses by convection are to be calculated but the surface area is unknown. So how to ...
43 views

### Delta Robot: Torque and Motor Sizing

Question: Is 56 Nm enough torque for a delta robot with the below dimensions and specs? If not, what would be the minimum torque needed? Thank you in advance for your help. I am working on a rotary ...
48 views

### How to derive phase equillibrium criteria for more than 2 phases mathematically?

I know the derivation of phase equilibrium criteria derivation for 2 phases. I am not getting how to extend the derivation to more than 2 phases. Please help me out on that. Thank you
22 views

### Why torsional warping does not occur for shafts with circular symmetry?

When we twist a shaft/beam/rod, shearing stresses are produced. The angle by which the end of the shaft rotates can be found as: $${\displaystyle \theta ={\frac {TL}{GJ}}}$$ where $T$ is torque, $L$ ...
39 views

17 views

### what impact does drop height have on powder segregation?

In the pharmaceutical environment, the drop height from the hopper to the area where it collects must be minimized. Tubes can be used to minimise the height. I know that it affects powder segregation. ...
17 views

### Solution of st venant equations using fortran

I tried to write code to solve st venant continuity and momentum equations in FORTRAN 90, with given slope and rainfall and find out the discharge. But I stuck in the procedure to find overland flow ...
8 views

### How does plant evapotranspiration reduce the required size of a chiller used to control the climate of an indoor farm?

When HVAC companies estimate the required size of a chiller unit for a greenhouse or an indoor farm, they reduce the estimated load by plant "transpiration cooling." I understand how transpiration ...
28 views

### Why is there no widely-used standardized unit for indentation hardness?

The last hundred years have seen a great degree of standardization of units, and the expression of units of measurement in standardized, instrument-agnostic, objective terms, often in the SI units. ...
71 views

### Buying Liquid Oxygen in Small Quantities

I am trying to work out costs and order parts for a small liquid fuelled rocket I have designed. My oxidiser is liquid oxygen but I can’t seem to find anywhere to purchase it on the internet. Does ...
29 views

### How to read the block diagram for the 2nd order integrator feedback system?

This is a prework for a lab, I haven't seen things in the picture before and have no idea on how to transfer this to an equation.
37 views

My RAM truck has a feature that intrigues me and I want to know how it works. In auto-dimmer mode, the truck will automatically put on low beams headlights when there is on-coming traffic at night, ...
75 views

### Installing satellite dish to point to local zenith

After receiving help on my previous post (Stopping/reducing wobbliness in threaded rod), I've decided to come back and ask another question: how can I actually hold the satellite dish into place? I ...
24 views

### Fluidic muscle in reverse, as a pump. Does this exist?

A fluidic muscle is a pneumatic or hydraulic actuator, consisting of a flexible tube. When the tube is filled with a working fluid (pressurized air or hydraulic oil), it balloons out and shortens. In ...
63 views

### Heat transfer coefficient of a cylindrical hot water storage tank depending on its size

I have a simulation model of a cylindrical hot water storage tank. The heat loss is determined by the surface area and the heat transfer coefficient. A configuration of the storage tank with 900 ...
40 views

### The elastic module for a paper bridge

I have build my own bridge from paper and i want to know the elastic module for the bridge, my bridge is flat all over the way and cylindrical from the sides.
88 views

### Determine surface area of arbitrary physical object

Assume a physical object with arbitrary shape whose dimensions are on the order of 1 meter. How would one measure the surface area of the object? There may be many reasons for determining the surface ...