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8
votes
2answers
651 views

How does nuclear fuel reprocessing work?

As far I know, the depleted fuel cells are crushed, and solved in nitric acid. What is coming after that? This nitric acid should probably contain a very wide spectrum of different salts (practically,...
8
votes
7answers
3k views

Why do we pave roads instead of making them from removable parts?

If roads were made of removable parts, we'd probably have fiber cable internet everywhere by now I'd say. It'd be so much easier to install e.g. new electricity and water infrastructure and to ...
7
votes
1answer
2k views

Why ductile materials fail in shear when subjected to torsion?

I was reading the book Mechanics of Materials by Beer and Johnston.The author points out in torsion chapter that ductile materials generally fail in shear.And brittle materials materials are weaker in ...
7
votes
2answers
2k views

How are blanking spades entered into gas pipelines?

I often see specifications for refurbishing works on gas pipelines calling for blanking spades, to separate the area worked on from the rest of the gas system. This is in addition to closing valves. ...
7
votes
2answers
630 views

How efficient are jet engine thrust reversers?

Most reasonably sized commercial aircraft rely on jet engines for propulsion. Upon landing these aircraft use a number of means to come to a stop with the two most important being (I believe) ...
7
votes
5answers
1k views

What was that?! Quantifying the impact of a martial arts strike

Measuring things like a martial artist's strike can be challenging because it is a complex motion and common vernacular will use imprecise or incorrect terms. This question is an attempt to identify ...
7
votes
1answer
618 views

How do I compute combined tensile strength?

If I know the tensile strength of a pin, how do I compute the total strength of multiple pins? That is, 2 objects are connected by multiple pins, evenly distributed, each with a height of $2mm$ and a ...
7
votes
5answers
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 ...
7
votes
1answer
1k views

Modeling Transient Heat Transfer between two 1-D materials

I have been working on creating a 1-D model of a material with a layer of heat resistant material stuck to it. For this I have been trying to use the implicit finite-differential method. The equations ...
7
votes
1answer
2k views

How do you check a weld for applied moment?

I have a single angle connected to a double angle via a 3/16" weld I know there is a factored, applied moment at that connection. I would like to ask how I can go about checking the capacity of this ...
6
votes
2answers
13k views

Why use a 'dogbone' shape for tensile testing specimens?

Why is that the shape of the tension test specimen a dogbone-like shape? I know that it is so that the deformation is confined to the narrow center region and to reduce the likelihood of fracture to ...
6
votes
2answers
3k views

Snap-fit design

I'm designing 2 objects that should be attached to each other and removed when it's necessary. So I though about snap-fit as a solution. There is a lot of types of snap-fit but I'm planing to use a ...
6
votes
2answers
174 views

Is it a problem to have two heat sources controlled for different temperatures on the same heating circuit?

This is the situation - I have three heat sources, called CHP, burner 1 and burner 2 on the same circuit. All three feed to the same heating manifold, with various heat demands. Preferably I want to ...
6
votes
3answers
358 views

What is the best way to control brightness of a LED?

LED brightness can be controlled using digitally controlled potentiometer such as a Microchip MCP413X or a PWM signal. In both cases the signal will be controlled/ generated from a micro-controller. ...
6
votes
5answers
6k views

How can I improve traction on a wheeled vehicle yet reduce friction?

This is inspired by a project I undertook for my Physics class last year; I'd like to apply it in the future. Background: For the project, I and a few classmates were required to build a small car ...
6
votes
5answers
8k views

Is hydrostatic pressure a dead load or a live load?

I have a structural analysis question. I want to know if the hydrostatic pressure in a water tank is a live load or a dead load and why?
6
votes
4answers
4k views

Create a DIY light tube

I am working on a project to bring light into a bunker. The bunker is 3-4 meters below the ground. I am looking into bringing natural light into the space, instead of using electricity. The space is ...
6
votes
3answers
3k views

Do references for the California PE application have to be California PE's?

Here is the link to the current CA PE Exam application: http://www.bpelsg.ca.gov/pubs/forms/ceapp.pdf Page 2, which is the list of engagements/references, states: For each engagement claimed ...
6
votes
2answers
4k views

How to strengthen an I beam

To save on material, I am requested to design a continuously supported beam with a maximum bending capacity that is half of its maximum bending moment and to strengthen the beam at certain intervals ...
6
votes
1answer
1k views

What are the technical differences between flexible and rigid solar panels?

During a recent search I discovered the existence of flexible solar panels. Besides the obvious differences of low weight and flexibility what are the high level technical differences between flexible ...
6
votes
2answers
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 ...
6
votes
2answers
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. ...
6
votes
3answers
1k views

How are loads transferred to bearing piles in a wall pier?

I've been working on the design of a reinforced concrete wall pier for a three-span bridge. I roughed out the design based on a number of example plan sets and now that I'm taking a crack at the ...
6
votes
0answers
443 views

Incompressible 2D pressure-driven flow: for Navier-Stokes equations in nondimensional form, how should I express pressure boundary conditions?

*I have updated this question. I'm using two codes for modeling incompressible, two-dimensional flow out of a tank. My fluid dynamics experience is pretty basic; I'm using the codes to understand a ...
6
votes
1answer
135 views

Multiphase Flow - Energy Coupling Parameter

I have a general question regarding energy coupling in multi phase flow. My question comes is based on the text from this book: https://books.google.co.uk/books?id=CioXotlGMiYC&pg=PA33&lpg=...
6
votes
2answers
302 views

Why does the standard $k-\epsilon$ model use zero equation models?

According to Hoffman, the standard $k-\epsilon$ turbulence model incorporates a two-layer approach (inner region and outer region formulations to reperesent mixing length) when it comes to regions ...
6
votes
2answers
100 views

Unexpected Results from my Transfer Function

I have a system that can be modeled with the following picture: There is a mass $m$ connected to a spring $k$ and a dashpot $d$. These are both connected to another dashpot $c$. A force $F(t)$ is ...
5
votes
2answers
1k views

What does 'Open Flow' mean for a pump flow rate?

I have specifications for a positive displacement pump where, in the data table on the last page, the given flow rate is referred to in the column header as 'Open Flow.' Is this the maximum flow ...
5
votes
1answer
101 views

Poisson ratio boundary condition

Let's say I have a large isotropic body in uniaxial tension, onto which a small rectangular piece of film is applied. Think of a strain gage on a big body, but the 'strain gage' is one single ...
5
votes
1answer
2k views

Sign convention in Mohr's circle

I don't really understand the explanation in the circled part of the image below (from here). From the diagram, we can see that the shear stress that cause the element to turn clockwise is positive, ...
5
votes
2answers
4k views

Does having 2 engines together increase anything?

If I have a vehicle (V1) with one 100 kW engine and an identical vehicle (V2) with 2 of these 100 kW engines, will this mean that V2 will have double the torque of V1 and double the top speed of V1? ...
5
votes
1answer
111 views

Make something that turns yet locked in place

I imagine this is an easy concept but I do not know much about mechanical engineering design. I am trying to make a "knob" like a control knob in solidworks that turns and is locked in place after ...
5
votes
1answer
1k views

How does the pressurized suspension of the Hyperloop not affect the tube pressure?

So one of the proposed suspension systems that will be used on the hyperloop include the externally pressurized air cushions. These cushions lift (or at least help lift) the capsule and reduce drag ...
5
votes
2answers
1k views

How to generate NACA 5 digit airfoil coordinates?

I want to generate NACA 63824 airfoil coordinates to use them in my bachelor thesis. I tried airfoil tools and java foil. But I can't generate 638xx series. Can you recommend me a program or a code ...
5
votes
4answers
359 views

How to compare utilization rates?

I have the utilization rates of several machines for each week over a year. These differ per week because of the occurrence of machine failures and changes of orders. Meaning that one week a machine ...
5
votes
7answers
2k views

Can I use AutoCAD to learn mechanical engineering by DOING (like programming)?

I would like to learn mechanical engineering as a side project. But, I would like to learn in a way similar to programming. Learn by doing. Of course I understand I can't build things automatically ...
5
votes
3answers
1k views

Mathematical representation of hinge and pin connection

Following on from this answer, I am reading about the difference between hinge and pin connections here, and I don't quite understand about it. I think I would need to see the mathematical ...
5
votes
2answers
571 views

Gigapascal pressures in a small package

How small/compact can a pump or other mechanism be, that would allow compressing gas (or liquid) to pressures of excess of 10GPa, continuously? Throughput may be minuscule, of order of milligrams per ...
5
votes
2answers
235 views

How do I conduct an experimental modal analysis with a three-axis accelerometer?

How can I compute the Frequency Response Function (FRF) if I use two three-axis MEMS accelerometer to measure the input excitation and output response? I have read from some books that the FRF can be ...
5
votes
1answer
104 views

Equating $\frac{dp}{dt}$ and $F$ at a hydraulic jump?

A journal I am reading about circular hydraulic jumps provides the equation and I quote: $H$ Depth after hydraulic jump, $h$ depth before hydraulic jump, $V$ velocity after hydraulic jump, $v$ ...
5
votes
1answer
781 views

How do I calculate rolling resistance for tire on pavement?

First condition assuming perfect rolling, no slip, from what I understand is that the rolling resistance coefficient can be calculated as the displacement arm of the normal force the tire "feels", in ...
5
votes
3answers
952 views

What level of vibration testing should I perform on my product?

I'm trying to determine a level of vibration testing I should perform on my product. I understand electrical stress/life testing and I'm looking for a mechanical equivalent. I have a DC motor running ...
5
votes
1answer
678 views

First principle derivation for torsional constant

For torsional constant, analytical formulas are available for some standard steel sections as shown in this wiki page. But what about arbitrary shapes? How can I obtain the formulas for torsional ...
5
votes
2answers
860 views

Design of a Four-Bar Infinity Coupler Linkage

How can I control a Four-Bar Infinity Coupler such that it does not accidentally become a Paralellogram Linkage? It seems to me that, when the bars are all horizontal, gravity could change the ...
5
votes
1answer
1k views

What is the script function to select Solid Body in ANSYS Design Modeler?

I need to select a solid body in ANSYS Design Modeler, with script, in a design with multiples bodies. With the following command I select all the solid bodies, but this is not what I need. ...
4
votes
2answers
103 views

Linearization of dynamic equations/transfer function in control theory

I've gone through a control theory course, and after looking back at what we covered and how the subject was taught to us, I still have quite a few questions (which I unfortunately did not ask in ...
4
votes
1answer
59 views

Do the steels 1.4404 and 1.4571 look the same?

A contractor delivered three components, all are supposed to be in 1.4571. Part A is actually done in 1.4404 / (X2CrNiMo17-12-2) (according to pretty conclusive documentation). Part B is allegedly ...
4
votes
2answers
116 views

The concept of flux

I find it difficult to understand the concept of flux and field.I have searched the internet and refered a few books.From what I understand, generally flux can be defined as "some quantity per unit of ...
4
votes
1answer
5k views

Determining mass flow rate and exit velocity of compressible flow

This one's a bit of a doozy, so please feel free to comment on any one single part or parts to this problem. The setup is simple--I have a container (an empty bottle) which I fill with a certain ...
4
votes
3answers
5k views

How can I determine the power generated by a regenerative braking system?

If I have an electric vehicle on an incline (m=17,300 kg) I want to figure out how much energy it would generate by regenerative braking. I've used $a= g \cdot \sin({\theta}) $ and $f=m\cdot a$. <...

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