# All Questions

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12 views

### Nonlinear behaviour of control plant and adaptive or robust design

In a paper in the context of controller design for DEAP actuators I came upon the following sentence: Furthermore, the nonlinear behavior of the control plant requires either an adaptive or a ...
18 views

### What's the most anisotropic material? Is there a dense stiffness matrix?

The stiffness (aka. tangent modulus of the stress) can be represented as a symmetric 6-by-6 matrix, i.e. it has 21 independent components in the most general case. In the linear case, this matrix is ...
19 views

### Building a room [closed]

I am going to build a simple room of one marla in my house. I want some estimate of expense of its construction. Please help me. I want to know - 1. What is the avg. price of one clay brick in India.2....
44 views

### Why do these piers have a height miss-match?

I found this image of 2 piers of a Grider bridge with varying height. By any change could this be part of the design? The bridge is supposed to be a flyover for traffic decongestion.
33 views

### Determining Support Reactions

I have a statics problem that I am running into some difficulties with. What is being asked here is to determine the support reaction at the points A and C. This would normally be no problem, but when ...
27 views

### Need Ideas: Sci Fi Handgun designed not to over-penetrate spaceship hull [closed]

TLDR: what kind of personal projectile weapons would you expect to see used in a pressurized space station in the near future, something that can have useful terminal effect on a person within 25-50 ...
17 views

### Max torque given in engine specification is indicated torque or brake torque?

I want to calculate brake torque from indicated torque for motorcycle.
27 views

### Double-bagging problem: which bag on the inside?

If you're double-bagging some groceries, and one of the bags has tears in it while the other is intact, which bag should go on the inside?
23 views

### Trying to reduce RPM of a combustion motor

I'm trying to reduce the rpm of a combustion motor. It operates at 2000 rpm with 3HP, and I need it to work at around 12 rpm (no matter the power). I've made the math with sprocket and chains, but the ...
17 views

### What practically is constant volume heat addition in SI piston engine? [closed]

Isochoric means constant volume (In SI engine: piston should not move when the spark is ignited). In reality piston always keeps displacing up and down means volume changes. So, how does this make it ...
27 views

### Silicone paste vs. silicone grease vs. silicone spray lube

For purposes of usage in home/auto and light industrial circumstances, what are the differences? What are the pros and cons, and suited uses, of each? Thanks!
26 views

### Is it possible to spot weld three rather than two plates?

I have a situation where ideally, I would like to resistance spot weld three rather than the usual two plates together (individual plate thickness approximately 0.7mm). Is this at all possible? If not,...
15 views

### What material characteristics are most important for heating element material selection?

I want construct a heating element by screen printing a flat coil pattern of conductive paste onto an insulated substrate. This conductive paste consists of a powder of conductive metal contained in a ...
49 views

### Why do we get singularities in a solutions while modelling a physical systems?

I wonder why do we get some times singularities (position to be infinity or velocity to be infinity) in the solutions while modelling a real system and in spite of taking all real parameter values of ...
34 views

### How can thin wire in generator windings carry the high output current?

I observed the rebuilding of a 12KW, 120V gas-powered generator. I was amazed at how small the generator portion was (roughly the size of an electric motor you might find in a major home appliance). ...
26 views

### Hydraulic linear actuators as CNC axis instead of screws

Lately I've been watching some videos on machining and hydraulics as it always interested me. I was toying with the idea of building a budget CNC mill with threaded rod for the axes, but the issue of ...
23 views

### Force applied to a cam follower

Hello I am a simple rock climber, and would like to figure out how much force is applied to The lobe of a cam/the rock when the cam is loaded. So the cam lobe is circle the ramp or cam goes from 7/16”-...
24 views

### what is the most optimal cost effective diameter of a hyperloop tube ferrying ALL cargo between the US and EU [closed]

what is the most optimal cost effective diameter of a hyperloop housing vacuum tube housing hyperloops that can ferry ALL cargo currently travelling by air and sea to and from the US and Europe? ...
9 views

### What is the most efficient high speed propulsion for a 30 tonne hyperloop 30 000km/h [closed]

What is the most efficient high speed propulsion for a 30 tonne hyperloop travelling at a min 27 000km/h, max 30 000km/h. is it maglev or electical motor and it sits on wheels?
9 views

### how large a vacuum pump would be required for a hyperloop travelling from the US to Europe

how large a vacuum pump would be required for a hyper-loop traveling from the US to Europe and how much energy would it use for both vacuum pump and 30 tonne maglev propelled hyper-loop maximum load ...
12 views

### Can a maglev propelled hyper-loop carrying a 30 tonne load travel at 27 000km/h [closed]

a) Can a maglev propelled hyper-loop carrying a 30 tonne load travel at 27 000km/h here on earth and... b) would the forces acting on the materials and its frame render one such structure impossible ...
37 views

### Can a computer be designed a different way? [closed]

I am wondering: Are all computers designed the same way (Mainly I mean the fundamental components are all the same?) Can these fundamental components be designed differently? I am trying to answer ...
37 views

### Statics Two Force Member Problem

I was given a challenge question from my teacher that I need some assistance in solving. The problem is to merely identify the two-force members. I understand the ideas of how to determine a two-force ...
11 views

### FOPDT model identification

So I'm trying to identify the model of a simple system (I'm pouring hot water (m [kg/s] into a water tank and displace the colder water inside) in order to tune a PID controller. I performed a doublet ...
680 views

### What are the design difference of a steel tank that would withstand 136atm inside and 1atm ambient compared to 1atm inside and 136atm ambient?

Let'say the steel tank would be submerged deep in the ocean with 136 atm ambient pressure then the other tank with the same material would just be used to contain 136 atm pressure. How would the ...
11 views

### determination of viscosity from the final velocity of a sphere that descends

From the BSL transport phenomena book at the end of chapter 2 on the stokes law, if it is assumed that in obtaining the stokes law the resistance includes the velocity of the fluid, why is the ...
41 views

### Constant force opposing hydraulic winch

I have a situation that I am hoping to solve with the use of electric motors, and a variety of controls. I have a hydraulic winch which turns at speeds from 0-60 RPM. This winch is coiling and ...
54 views

### Calculating shaft diameter

I'm designing a circular shaft that's going to carry a spread radial load of about 200kg and also transmit a 160Nm torque. I'm not very familiar with materials but what I'm guessing I'll be able to ...
29 views

### Spring Loaded Pin with Chamfered Pin Finish?

I would like to try out a component that operates like a combination of the two pictures provided - spring loaded pull pin, with a pin finish like a tubular latch (chamfered/filleted finish). Do ...
50 views

### Pressure recovery in turbomachinery

Diffusers in turbomachinery are used to transfer some of the kinetic energy of the fluid to pressure energy and to direct the fluid to the ducting/second stage/... I understand this and the mechanism ...
9 views

### What is the connection between rate of transfer of a substance and the amount recovered? [closed]

I was going through a Homework problem which asked would you increase or decrease the flow rate to increase amount recovered
38 views

### How to size a rectangular steel tube to hold certain weight?

I would like to build a shelf (1m width and 0.5m depth) using only four rectangular steel tubes on for legs. Each legs are at the end of the rectangular tube. I would like to put 500kg on the tubes, ...
46 views

### How to compare two acceleration sensors side-by-side?

I have a single axis analog capacitive acceleration sensor (from PCB Piezotronics) which is very reliable but expensive. Now I need more axis, unfortunately can not afford buying anymore. So I have ...
16 views

### How to install a doorway through a stone wall where a barrel ceiling is on one side

We have an old stone built cottage. We have a garage we are converting to a bathroom. The garage roof is a barrel brick ceiling. We need to break through from the house to the garage but need to ...
5 views

### Tg and vitrification

If the particular reaction temperature is lower than the value of Tg at full conversion, Tg∞ = Tg(x = 1), a conversion will be reached where Tg(x) equals T(reaction temperature) and vitrification of ...
28 views

### Creep behavior in metals

If creep behavior can begin at 0.6T(melting) but, hot working for a pure metal starts at 0.4Tm, what is the explanation for this?
21 views

### Why did ramjet AA missiles fall out of favor over pure rockets?

In the 50's and 60's, when anti aircraft missile technology was blooming, many designs used ramjet engines brought up to operating speed by rockets. This seems like a good idea, since ramjets have ...
25 views

### Sealing thrips out of monitors

I don't know if this is the correct forum as I can't find any suitable tags. We operate some of our equipment in fields inside tents. Our big problem is thrips/thunder flies. They somehow make it ...
91 views

### Concrete Slab Deformation

The concrete slab (?) supporting the swimming pool (≈ 10 x 10m x 1m) of my building has clearly a 'belly': I'm not sure whether this was built this way or evolved over time, however, my best guess is ...
56 views

### Dyke improvement

I'm a civil engineering student, and it's my first year at the University of Applied Sciences, and I'm doing an exercise but can't figure out one of its parts. The question: what are the advantages ...
13 views

Im expanding my 28' wide single story composite shingle home. I want to come out perpendicular off 1 plane of the roof to expand master bedroom, and then remove the wall. The foundation is crawl ...
34 views

### Is CNC milling on metals always followed by heat treatment?

CNC milling causes residual stresses in metals. So, after CNC milling of a metal part, say aluminium, do all manufacturers (I'm not referring to any specific manufacturer, just generally) heat treat ...
45 views

### Modification of Beam Equation for Thin Sheet

I am trying to determine the modulus of elasticity (Young's Modulus) for a rigid paper sheet. The issue I am having is that my results for the Young's Modulus change depending on what orientation (...
22 views

### How is the Outlet flow rate in a water system controlled?

The Hardy Cross method for analysis of fluid systems assumes that in inlet flows and outlet flows for the system are known. However, when one constructs such a system in real life, how do we ensure ...
63 views

### Deflection Of Beam In Structural Rigid Jointed Frame

This is a recommended follow on to one of my previous questions. It was stated that I could find the deflections of a beam by idealising it as a simply supported beam and then calculating accordingly. ...
48 views

### What are these reflective triangles on the sides of train track rails for?

Last night while waiting for the train at South Yarra station in Melbourne, I saw these reflective triangles stuck on the sides of the train track rails. They were evenly spaced a few metres apart for ...
24 views

### Do companies recover CO2 and water from the purification step of cryogenic air separation, and how?

In the 3rd step of cryogenic air separation, filtered air is purified to remove water, CO2, and hydrocarbons from the N2-O2-Ar stream. Im interested in knowing what happens with that CO2 and water. ...
11 views

### Reformulate navier-stokes in terms of perturbation

I am reading this paper and trying to understand on page 14-15, First it rewrites Navier-Stokes in terms of a ''zero order problem'', and where $u_i = \mathscr{U}_i + u_i'$ , where $U_i$ is the base ...
What is the definition of rate $(−ra)=−\frac{dCa}{dt}$ or $(−ra)=−1/V\frac{dNa}{dt}$ ? I think the general one is the second one and first one is for constant volume reaction system. Is the above ...