All Questions

Filter by
Sorted by
Tagged with
0
votes
0answers
4 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, ...
0
votes
0answers
6 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 ...
3
votes
2answers
569 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 ...
0
votes
1answer
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?
0
votes
0answers
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 ...
0
votes
0answers
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 ...
0
votes
1answer
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 (...
1
vote
2answers
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 ...
0
votes
1answer
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. ...
0
votes
1answer
73 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 ...
0
votes
0answers
39 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 ...
0
votes
0answers
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 ...
0
votes
1answer
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))....
0
votes
1answer
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 ...
0
votes
2answers
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, $L$ ...
0
votes
0answers
18 views

why do they put a ring on a planetary gear and why dont they turn it with a gear in the middle

why do they put a ring on a planetary gear why don't they just put a gear in the center I want to know if the ring adds torque thank you if anyone knows
0
votes
0answers
16 views

How to calculate how many solar panels can be connected to one inverter?

I am a bit confused about inverter specs, and most sources online seem to focus only on the power ratings. As far as I understand, if an inverter is rated at 100kW, and a solar panel is able to ...
3
votes
2answers
54 views

Why rectangular windows are so common?

Most of the windows in our rooms are mostly rectangular.Why don't we chose any other shape like circle,triangle or a trapezium.Does it affects airflow through room? Is the reason is that they look ...
1
vote
3answers
29 views

Huge gap between ceiling and floor above

I guess this question would belong on an architecture page if Stack had one. There is a 5 story building I was in recently that had fairly low ceilings (maybe about 8 feet) and a huge gap between ...
-1
votes
0answers
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 ...
1
vote
1answer
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. ...
0
votes
0answers
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 ...
0
votes
0answers
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. ...
0
votes
1answer
21 views

Normal Force distribution of Prism

On the image below there is a regular prism which is angled by $\alpha$. The (black) mass m1 applies a torque $M_k$. The mass m2, which is the rest of the Body applies the torque $M_s$ In the ...
0
votes
0answers
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 ...
0
votes
1answer
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.
0
votes
0answers
12 views

N2O/Kerosene Rocket Fuel

I am interested in building a small liquid fuel rocket and I have decided to use nitrous oxide and kerosene as the oxidiser and fuel respectively. I would like to know if anyone has any advice ...
3
votes
2answers
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 ...
1
vote
0answers
11 views

Choosing Pressure Vessel head

Can I use a conical head at the bottom for a small diameter steam manifold ( Schedule 40- 3 inch dia. and 2 inch dia. ) that needs to operate at high temperature (~450 deg Celcius) and High design ...
2
votes
1answer
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 ...
0
votes
0answers
16 views

How do split drawings from this without losing their dimension Autocad

I have a dxf file converted to dwg (unit: millimeters). There are 6 different drawings in the same file, How do I split those to different sheet. I wanted to take their consumption, as they are going ...
3
votes
3answers
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 ...
0
votes
1answer
19 views

compute the maximum resisting torque that can be overcome by the system at the shaft axis

A 2Nm motor M is used to drive the system through a gear drive and a chain drive. the overall reduction ratio is to be between 16:1 and 18:1, and at an output speed of 6rpm.
0
votes
1answer
18 views

For a tangent ogive, given a radius, can you determine it's length?

A tangent ogive body has a specific radius for a given length, so how would you determine length if only given the radius?
8
votes
7answers
7k views

Why is hydro-electric power still scarce in some places?

70% of the Earth's surface is covered in water, why can't a hydroelectric power plant be set up on each and every river? Is it that its too expensive? Why is electricity still a problem in countries ...
0
votes
0answers
15 views

How to calculate the force required to move this water bot with certain speed

This is my project where I have created a river cleaning machine. It works fine but no actual calculations have been done regarding the power requirement of motors(A software engineer ). The machine ...
0
votes
0answers
18 views

Python control module initial condition response

In python control module in initial condition response I am confused by what is meant here by initial condition. Because both state space object and transfer function object can be entered. For state ...
0
votes
1answer
23 views

How do I calculate the bite force of a mechanical gripper jaw? Which software can be used to simulate the same?

I plan to mount a gripper mechanism on a drone to grip a payload. How do I calculate the force generated by the gripper to hold a given weight. What simulation software can be used to simulate the ...
0
votes
1answer
19 views

Volume of air required to keep electrical box cool

I have a steel electrical box that is 15cm x 15cm x 10cm. The weight of the box is 1kg. Inside the box is a relay that loses 30 Watts of heat while in operation (it's attached to a heat sink that ...
0
votes
1answer
17 views

Single Split Air Conditioner & Supply/Exhaust Fan

First Question Does single split AC (the type with evaporator indoor and compressor outdoor) vent or exhaust air outside and thereby create negative air pressure in the room? Reason being I am ...
3
votes
1answer
49 views

How are water-tight transmissions made, like the kind you see on inboard boats, pumps or food blenders?

I want to replicate the kind of interface you see on inboard boats, pumps, or food blenders. Basically, I want put a motor in a sealed vessel, and have it turn a prop outside the vessel, in water. ...
1
vote
0answers
16 views

Extracting load info on Abaqus with Python

I have a model on Abaqus that I've managed to run some 85 jobs on manually. Between jobs, only the loads vary, and I select these loads by resuming what I need and suppressing what I don't with my ...
0
votes
1answer
20 views

How this agv rotates without rotating the payload?

How does the agv carrying payloads of huge heights as compared to it's size turn without turning the payload? Even if the body is attached to a center bearing, the bearing is very smooth then how come ...
3
votes
1answer
42 views

What is the thermodynamic consideration so almost all air conditioners are installed on top?

Almost all air conditioners (AC) are installed on top. For house small office use, will be like the picture. For office with central air conditioner, the blowing come from the ceiling through duct. ...
0
votes
0answers
22 views

Motion of an object due to movement of ship

I wanted to know how the movement of the object floating near the boat would be like. I've assumed the following scenario: The floating object is at the location $(x, y)$. The boat starts moving from ...
1
vote
1answer
62 views

threading a compression clamp

I'm not an engineer, just a novice hobbyist, so I'm not sure my terminology "compression clamp" is correct, but I'm attaching a drawing showing what I'm trying to accomplish. This plate will be ...
0
votes
0answers
24 views

H infinity control problem - changing eigenvalues of plant

I'm applying $H_\infty$ approach to control a system with a given input $u$, and I can measure and feedback position and velocity errors. The plant is described by the following transfer function $$...
0
votes
0answers
18 views

Swim platform supports

I have a swim platform on the back of my boat that extends 24” from the transom. It is supported by 5- 1” diameter stainless steel arms that are attached To the transom 13” below the platform and at 2”...
0
votes
0answers
49 views

Is my understanding of the Chernobyl explosions correct?

I have been reading technical reports and whatnot about Chernobyl for some time, and I'm feeling that they-or their wording-is not quite letting me understand it. For lack of a better way to present ...
1
vote
0answers
47 views

The optical encoder resolution

The optical encoder has a code wheel with a single track of slots and two photodetectors. The photodetectors are positioned so that they produce signals with a 90 degree phase difference. I want to ...

15 30 50 per page