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5 views

Is an axial force applied at the centre of a beam considered a compressive force, tensile force, or both?

I was looking through some course notes and realized that I never fully understood this concept. So, looking at the diagram below we can see that there is a 20kN axial force being applied in-between ...
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1answer
15 views

What is the difference between a sum of moments about a point versus the moment at a point?

In class we're learning about moments, and I'm not entirely sure what is the difference between using an equation of equilibrium for the moments about a point (in this case C), and the actual moment ...
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0answers
21 views

Guidance for a CAD model of a product

Hi Everyone! I am a novice in CAD modeling, and I am familiar with only two CAD tools - Autodesk fusion 360 and Solidworks. I want to make a CAD model of a product with the outer pod or shell as seen ...
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0answers
17 views

what is the torque difference in single plate clutch disks and multidisk clutches?

I have a review question that I am not sure about the answer. The question goes like this: "In comparison to single plate clutches, multidisk clutches are associated to which of the below notions?...
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1answer
32 views

What is the corresponding transfer function between r and y?

What is the corresponding transfer function between r and y?? I have tried $$ \frac{( \frac{k_i}{s}+k_p+k_d\ s )\times P(s)}{1-(-1)(\frac{k_i}{s}+k_p+k_d\ s)\times P(s)} $$
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0answers
13 views

How can I join a assortment of points kind of forming an ellipse but not a perfect one

I have already tried spline lines and polyline. I just want to join the points so that they form a curve, its not a perfect ellipse therefore I am not able to get the desired result from the ellipse ...
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0answers
20 views

Jacobians and Manipulator Dynamics

This is a Stanford Manipulator I started off working on it by initially setting up the DH table Transformation Matrix and then Homogeneous Transformation Matrix I started finding the linear and ...
0
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2answers
36 views

Can we say that stress strain curve for a tensile test is function of strain rate and temperature?

I am currently studying about tensile test where it is saying that it is conducted at a constant strain rate. Also, it is said that it is conducted at a particular temperature. So can we say that ...
0
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1answer
28 views

How to extract a broken 6.5mm plug from jack?

One of my 6.5mm adapter was broken and the heading pieces was kept in the jack. (picture atatched) What tool should I use to extract the broken part?
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0answers
48 views

How can I pull up an NIV (non-invasive ventilation) mask using a motor?

Continuous use of non-invasive ventilation mask causes facial pressure ulcers in some people. I am creating a system of measuring the pressure, temperature of skin under the mask and if the risk of ...
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0answers
47 views

Mounting grinding wheels on a threaded rod

I'm trying to mount a set of 6" grinding wheels on an M12 threaded rod. The problem I have is keeping them perpendicular to the rod so that they don't wobble when they turn. The wheels have a 1&...
1
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3answers
56 views

Mathematical derivation for 1st law of thermodynamics

Mathematical derivation for 1st law of thermodynamics : What I know : 1st law of thermodynamics is known as or derived as the conservation of energy . But how are the terms U , q and W derived from ...
1
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0answers
22 views

Would you recommend Delmia works [closed]

I Have a customer that is looking to setup some sort of lean erp system at his business. Has anyone used/setup Delmia Works in their business, would you recommend another product that plays well with ...
2
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0answers
20 views

Durability & air-tightness of PUR tube on barbed air port

I'd like to connect a long tube to a pressure sensor with a barbed port to measure air pressure (ambient air pressure +-10kPa). The sensor's barbed port has outer diameter 3mm. I'm choosing between ...
1
vote
1answer
46 views

What does “rigid steel” mean in electrical construction plans and specs

Reference to rigid steel is made in specs with reference to metal conduit. A commenter wanted to add 316 stainless steel as the material but this verbiage with regards to "rigid steel" still ...
2
votes
3answers
56 views

Boundary condition at supported end of a rod

I have one end of a rod held in a hole of a 'rigid' part with no clearance, while the other end is loaded with a force. I have shown 3 simple reaction-force models in the picture. If my intent is to ...
1
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0answers
24 views

Find system equations for the system shown in the figure and F-V analogous circuit

Can't seem to understand how the 2 bodies would interact with each other. For most other problems I use the Nodal method by using the displacements as nodes and then connecting all other elements to ...
1
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3answers
102 views

Can/do Civil Engineers do “hands-on work” such as physically partake in building the infrastructure as well?

Peace and Blessings. While doing research about the Civil Engineering profession, I see that they typically do a lot of computer work, desk work, meetings, and fieldwork in the sense of overseeing ...
4
votes
1answer
45 views

Filling gaps in heatsink design to improve thermal conductance?

I am currently pondering modifying my laptop's heatsink and am curious whether I stand to gain any benefit at all. The CPU and GPU (similar heatsink design) reach high temperatures (90°C +) under load ...
22
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5answers
5k views

Why exactly does a washer help distribute the stress around a bolt?

Usually the reason for having a washer under a bolt head is stated to be that it helps to evenly distribute the stress to the clamped material surface. But why is this? I would understand if the ...
1
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0answers
17 views

What are the IEC IP standards/code for electric vehicles?

What an end consumer should know about the level of IP protection provided for a vehicle against hazards which include but not limited to environmental factors, thermal runaway in batteries, etc.
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0answers
23 views

Effect of area spring at slab on column

Say that a simple building is supported by 4 columns , the column sitting on base slab. I assigned some sort of area spring to the base slab. When the area spring assigned is higher, this cause the ...
2
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0answers
15 views

Non-Dimensionalizing Navier-Stokes equation to derive the Thin-Film Equation

I want to start with the general Navier-Stokes equation in 3-D: $$ \frac{\partial \vec{u}}{\partial t} + (\vec{u}\cdot\nabla)\vec{u}=-\frac{1}{\rho}\nabla p+\frac{\mu}{\rho}\nabla^2\vec{u}+g\sin{\...
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0answers
61 views

Does anybody know what this symbol is?

The last couple of weeks, I've been noticing this (wifi like) symbol next to some of my contacts in my Android phone. The symbol I am interested about is in the red circle that has the outline of the ...
1
vote
1answer
36 views

Can I use empirical formula ,time period T=0.1*N, (N= number of floors) to find fundamental frequency of vibration of Tesla's lab building in1890?

I want to know ,can I use the empirical formula time period T=0.1*N, where N = number of floors, to find the fundamental frequency of vibration of Tesla's laboratory building in which he performed ...
2
votes
1answer
68 views

What is the physical significance of bolt elongation length?

Eurocode: design of steel connections mentions something called "bolt elogation length", defined as the grip length of the bolt plus half of the sum of bolt head height and nut height. But ...
0
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0answers
37 views

How fast can the Shinkansen N700 train take a curve?

As a transit advocate, I'm evaluating an urban freeway corridor for high-speed rail. Given the geometry of the existing highway, the track alignment will be a compromise between train speed and right-...
1
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0answers
17 views

Design specifications Venera 13/14 [closed]

I am trying to 3D model the Venera 13 or Venera 14 spacecraft. These are Russian spacecraft from the 1980s. I am looking for design specifications, plans, schematics, or anything else that might make ...
1
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0answers
29 views

Gel Strength of water [closed]

I have been checking for the 10 seconds and 10 minutes gel Strength of water but has not seen any reasonable answer anywhere or maybe I have but don't understand.
1
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1answer
112 views

Can the Elastic Modulus of an isotropic material be different in Tension and in compression?

I was conducting a FEA analysis of a symmetric isotropic structure under a loading condition. I will not mention the material I was using. Under that loading, one part of the structure was in tension ...
1
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2answers
35 views

Youngs modulus in ASTM specification A36

In ASTM A36 I cannot find a single mention of the Youngs modulus of the material. It does mention the tensile strength and yield point among other things. Where is such information normally indicated ...
1
vote
1answer
63 views

How do I configure my arduino to use the 628512LP-70 as an external RAM?

I am aware this could cause some serious lag issues. However, I only intend to use that RAM to fill the display buffer for the LCD (240 * 320 pixels). I can't store all of this data in my Arduino's ...
2
votes
1answer
52 views

A Bonus homework question in Elementary Statics. A painter on a ladder put on a ledge [closed]

we have been asked about a bonus question in Basic Statics as mentioned below. I would be glad if someone help me with it. The question is: There is a painter which is going to work on a ladder as ...
1
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1answer
50 views

What are the design differences between a hydrogen bomb and a neutron bomb?

Are the presence of neutron reflectors the only difference between a hydrogen bomb and a neutron bomb? Many sources go into the bombs' different effects but I couldn't find the differences in how they'...
0
votes
1answer
36 views

What does it mean by average kinetic energy of molecules as temperature?

We say kinetic of molecules as a function of temperature from the equipartition theorem. This means that more is the velocity or mass of the body , more the is the temperature. My Q is why does ...
2
votes
1answer
84 views

Modeling rigid body dynamics: Trouble with equations, encountering nonsense answers

Hi, I am working on modeling a simple rigid body dynamic system through a certain range of motion. Here is the picture of the system. I am trying to solve the system for the variables $x_1'', y_1'', ...
1
vote
3answers
70 views

Mechanical fasteners made of HDPE?

I need to fasten pieces of HDPE together but I’ve heard gluing HDPE is difficult (after all, glue comes in HDPE containers, and the glue doesn’t get stuck in the bottle). Using mechanical fasteners ...
1
vote
1answer
46 views

Difficulty in understand the meaning of standard enthalpy of formation

Standard enthalpy of formation is when one mole of compound is formed from its constituent elements. Example : $H_2$(g) + $O_2$(g) —>$ H_2O$(L). But we don’t say the same for $CaO + CO_2$ —> $...
1
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0answers
20 views

Problem with relationship between shunt resistance and grain boundaries in a solar cell

Here is the correct answer from another stack website: electronics.stackexchange.com/a/570917/288858 The higher shunt resistance means that higher the polycrystalline lattice irregularity and many ...
1
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2answers
42 views

Where to place air, water and electric cables in a composite beam [closed]

If water, gas and electrical cables have to pass through three (3) openings provided in the cross section shown in Figure 2, with tangible and scientific arguments specify the adequate opening for ...
1
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2answers
60 views

Why would an oxygen concentrator warrant an “Oxygen in Use” warning for firefighters?

I needed to use a medical oxygen concentrator for a short period, and I found it strange that it came with a warning label I was supposed to put in the window so firefighters would know it was there. ...
1
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0answers
35 views

Can I use a coffee cup Stirling engine to generate power?

I want to generate electricity to power an led using a coffee cup Stirling engine. Will it provide enough power, or should I use something like a gearbox? Or will it do the job in the first place? ...
1
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0answers
35 views

Lyaponuv stability condition of linear systems for homogenous P in V(x) = x^T P x

I am currently learning about using Lyaponuv functions to find Linear Matrix Inequalities (LMIs) as conditions for stability of a linear time invariant system. i.e. $$ \dot{x}(t) = Ax(t) $$ is stable ...
1
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2answers
56 views

How does the stiffness of semicircular beams connected in series increases?

I am working to reduce the deflection in a cantilever/ dive board at work.$300 mm(L) \times 30mm(B) \times 2 mm(H)$, i.e. it's a rectangular cross section currently. I can't change the material, or ...
1
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1answer
35 views

surface temperature due to constant heat flux

Imagine a hollow cylinder with the outside surface exposed to air (convection). If there is a constant heat flux on the inside surface how would I calculate both the inside and outside surface ...
0
votes
1answer
37 views

Why is the beam bending stiffness taken as $EI/L$?

In moment distribution method, the bending stiffness of a beam is taken as $EI/L$. But in these kinds of stiffness tables, the flexural rigidity is usually divided by some power of $L$: So why is $EI$...
0
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0answers
28 views

Cases in finding the maximum weight of the block

I am dealing with this problem about belt and dry friction. I need to find the maximum allowable weight of block B to maintain static equilibrium. I have given value of weight of the block A. The line ...
0
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0answers
19 views

What is a safe and efficient temperature range for absorption chiller generators?

I've read that the role generators play in the absorption chiller cycle is to concentrate the salt solution so that the evaporator/absorber can maintain a vacuum by constant absorption of vapour ...
0
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0answers
25 views

What is the text book to be followed for Cambridge Engineering Tripos Part IB, 2P2: Structures? [closed]

I need a text book to be followed for Cambridge University Engineering Tripos Part IB, 2P2: Structures which includes the following topics. Thin-walled Structures, Analysis of Stress and Strain, ...
0
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1answer
23 views

How Do I Calculate the Velocity of the Flow That Is Sucked Into Two Parallel Walls by a Fast Moving Flow?

I'm trying to solve a problem where I calculate the velocity of the setup bellow. Basically I have two very long(basically infinite for calculation purposes) plates, and I have one central jet of gas ...

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