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2,239 questions with no upvoted or accepted answers
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18
votes
1answer
383 views

Is there a method to determine the runoff for arid areas in developing countries?

Note: this question was totally rephrased and expanded on, addressing the comments and questions posed to the first version. The de-facto standard source for runoff calculations in South Africa is ...
13
votes
1answer
336 views

Determining RTK parameters for runoff analysis

I am examining a watershed and determining runoff using the RTK method. I basically use a 'guess and check the hydrograph' method right now. I've seen calibrators that use a mutation and convergence ...
11
votes
1answer
171 views

How do the bubble oscillations in two-phase flows affect the dissipation rate of turbulent kinetic energy?

I am investigating the effects of bubble oscillations (calculated using the Rayleigh-Plesset equation for bubble dynamics) on the turbulence in two-phase flows. Since I am using cryogenic fluids, the ...
9
votes
0answers
1k views

ANSYS APDL Shape memory effect option of SMA not working

I am trying to define the material properties of a shape memory alloy material in ANSYS APDL V15. There are material properties for Superelastic materials (SUPE option) and material properties for ...
8
votes
2answers
164 views

Can high alloy tool steels be quenched in brine?

It is will known that most of tool steels are quenched in oil to prevent cracking and distortion which appears when quenching in water due to non-uniform cooling caused by formation of insulating ...
8
votes
0answers
193 views

Forcing a part into “home position”

I have a design with two parts (at the moment): a fixed 10cm ring with vertical tracks a freely rotating block with a cut that may freely slide along that tracks: I'm trying to find a low profile ...
8
votes
0answers
159 views

Sketching an engineering system in healthcare

I am about to do a project about engineering systems in a Systems Engineering course. I need to sketch an engineering system in which clinical decision support systems are being used to diagnose ...
8
votes
1answer
123 views

How can I estimate blocking window distance in an sCMOS sensor setup?

I am trying to establish an appropriate distance between a spectrograph output window and a CMOS sensor. The spectrograph creates a focused image on the CMOS sensor but I am trying to restrict the ...
7
votes
1answer
149 views

How to optimise feed-forward control of a process based on a prediction using the prediction confidence?

I'm looking for a control method for a production process with the following characteristics: 1 control variable many process parameters (+-50) 1 resulting variable continuous measurement of ...
7
votes
0answers
487 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 ...
7
votes
0answers
484 views

BER peroformance of MPSK and MQAM in Rayleigh fading channel

I have a question regarding bit error rate (BER) performance over the Rayleigh channel. I observed BER performance over the AWGN channel using Simulink in MATLAB. I used to change the "SNR" parameter ...
7
votes
0answers
6k views

Residuals of continuity not converging

I'm simulating a turbine. The convergence of solution is monitored by checking the residuals of the numerically solved governing equations. The "viscous-spalarat-almaras" model is used, and used air ...
6
votes
2answers
188 views

Calculation of the stored energy for a heat storage tank

There is a heat storage tank that is directly loaded from the top and the heat is also taken from the top. The colder water from the heating circuit return flow enters the heat storage tank at the ...
6
votes
1answer
86 views

LED Lumen Calculations

I am using an LED as a point source for a school project. I have two questions in regards to the LED(s). I know that light follows the inverse square law when measuring perceived brightness, but all ...
6
votes
1answer
180 views

System Dynamics Modeling

I am trying to model this system but am having difficulties in setting up the equations of motion. This is a simplified model of a motorcycle suspension system, where P is the ground in the image ...
6
votes
1answer
300 views

Industry standard factor of safety for ballast design

What design standards exist for the design of ballast against uplift forces, and what factor of safety against uplift do these design standards promulgate? I am familiar with a typical FS of roughly 1....
6
votes
1answer
790 views

Design of transverse reinforcement in a wide beam

Besides satisfying nominal bar provision in the code, is there any special requirement in the provision of transverse reinforcement to ensure that the longitudinal reinforcement is fully effective in ...
6
votes
1answer
146 views

Derive a heat equation for a shrinking nanoparticle

I consider a spherical nanoparticle (NP) that is shrinking, for instance due to a melting process. I know that the pressure $p$ is proportional to $1/R(t)$, where $R(t)$ is the radius of the NP at ...
6
votes
0answers
536 views

How does LTE eNodeB set the Base Station output power?

I'm interested into the power radiated out of an eNodeB (LTE/4G) radio base station: which parameters does this power depend on, if they are constant or relying on the environment... All of this in ...
6
votes
0answers
274 views

I-beam annotation for tube on drawing

I have been sent a clip of a drawing with the following annotations on it, but I've never seen them before and can't figure out what they mean. Is there a standard interpretation of these callouts? ...
6
votes
1answer
675 views

(Non)simultaneous prestressing anchorage slip losses

Post-tensioned prestressed concrete beams suffer from a multitude of losses. When jacked, they suffer friction losses and their tension diagram is, for example (to simplify the drawing, I'm using the ...
5
votes
1answer
69 views

What approaches are there for demolishing a structure and how is an approach chosen?

From my office on the 21st floor of a building in Vancouver, BC two parking garages in the process of being demolished are visible. A third is just out of view a few more blocks away. One of these ...
5
votes
0answers
195 views

I want to understand this pneumatic circuit

I have trouble understanding the following pneumatic circuit diagram: I am new to reading circuit diagrams and i am unfamiliar with some of the symbols. I would appreciate if somebody could explain ...
5
votes
0answers
72 views

What diameter of particles will result in a blocked borehole?

My mine is looking to install a 600 mm open borehole to drop particles up to 150 mm through. It's a 320m shaft to drop ballast down to save time compared to using the drift. When it gets blocked ...
5
votes
0answers
29 views

Why do modern MRI scanners use an axial static field?

Last night I was reading some fascinating history of the first full-body MRI scanner and noticed that it's fundamentally different from modern scanners in one particular way: the static B field is ...
5
votes
1answer
202 views

Questions regarding Cornering Stiffness for RC Car

I am a bachelor's level student tasked with modeling the vehicle dynamics of an RC Car that will be made to drive autonomously. I lack prior experience or particularly specific education with vehicle ...
5
votes
3answers
143 views

Need some advice, control system animation. Appreciate some help!

I would like to have a 3d simulation of a helicopter landing on a ship. I thought about using matlab for this, as a far as I know you can connect models from Simulink to virtual worlds using blocks, ...
5
votes
1answer
258 views

Deriving the amplitude of a coulomb (dry friction) damped spring

This is my first time posting anything, but I could not figure out the derivation of the amplitude of the spring for the 4 first oscillations. I am not acquainted with the effect and calculations of ...
5
votes
0answers
45 views

Is the viscosity solution of Hamilton-Jacobi equation of practical use in optimal control?

My understanding is, given an optimal control problem, one can show that the optimal cost satisfies a Hamilton-Jacobi PDE and use dynamic programming to figure out the optimal control. However, ...
5
votes
2answers
184 views

Eccentricity for staggered 2x4 wal

I have a staggered 2x4 wall on a 2x6 sill plate as illustrated below (16" on center on each side = 8" on center each stud). The wall is loaded from both sides by floor joists, so I would ...
5
votes
2answers
4k views

How to find press fit/ slip fit for non standard size parts?

I am looking for calculator or chart for slip fit and press fit for non standard size parts. For example, I have oversized dowel pin 10mm +0.03/+0.01 diameter. I need to create a slip fit hole for ...
5
votes
1answer
370 views

Fluid dynamics of non interacting tanks in series

I have a system like this: and I have to estimate the height of the lower tank. First of all, I'm considering that I have a non-viscous, incompressible fluid in steady flow. Base apertures The ...
5
votes
0answers
116 views

PI-Controler: Comparison of characteristic equations

I have to design a PI-controller with zero order hold for the plant $G_s(s) = \frac{0.24}{(s+4)(s+12)}$ to meet the specifications of $\omega_n=5\,s^{-1}$ and $\zeta = 0.6$. I choose a $T=0.12\,s$ ...
5
votes
1answer
259 views

How to make a conductive paint over PDMS?

Conductive paint by conventional technique using gum and graphite powder does not stick to the PDMS surface and comes off once the paint dries. How else can I make a conductive connection over the ...
5
votes
1answer
84 views

PATRAN Order of Operations

To preface this question, almost all of my FEA experience has come from SolidWorks, so I haven't had to deal with these types of problems. I'm designing a truss structure in PATRAN composed of 1D ...
5
votes
2answers
306 views

On a Diesel/hydraulic DMU train what exactly does the “go faster” lever control?

Let's say that you are driving a Diesel Multiple Unit† with either mechanical* (i.e. an actual gearbox with multiple ratios) or hydraulic (i.e. two or more torque converters) transmission. When you ...
5
votes
0answers
114 views

Thin film sheet-resistance (van der Pauw method)

A well-known method to measure sheet resistance is the van der Pauw method. Looking at Wikipedia they state that the cloverleaf configuration is the most advised. Two questions naturally arise: Why ...
5
votes
0answers
116 views

What is the theory behind Eurocode 1 - Part 2: Traffic loads on bridges?

I'm interested in some theory Eurocode 1: Actions on structures - Part 2: Traffic loads on bridges. How were the limits chosen (e.g. maximum deck acceleration = 3.50 m/s2)? Why is the lower limit of $...
5
votes
1answer
379 views

What is the equivalent moment of inertia of a two-pivot pendulum?

I am working on a system that consists of a hanging-pendulum thrust balance with two pivot points, one in the front and one in the back There is a heavy weight applied in the front. I can change the ...
5
votes
0answers
107 views

How do DC motor parameters scale with motor size?

Consider the following DC motor parameters: Rotor resistance, $R\ [\Omega]$ Motor constant, $k_t\ [\mathrm{V/rpm}]$ Inertia, $I\ [\mathrm{kg\cdot m^2]}$ How do they scale with motor size? Do $R$ and ...
5
votes
0answers
65 views

Are Green strain calculations apt for volumetric strains?

I am trying to calculate large volumetric strains but I am somewhat confused whether Green strain is the right thing to be using or whether I should use good old-fashioned engineering strain. The ...
5
votes
0answers
109 views

Schematic Reading - Fluid Control Limit Switch Question

Does limit switch LS1 remain pressed on until the piston moves to LS2?
5
votes
1answer
832 views

How can we derived the equivalent Lumped Mass Model for irregular building and how to calculate the errors?

Intuitively, building can be represented as a lumped mass model ( the taller the merrier!): Assuming a building is a lumped mass cantilever column also makes the global stability checks easier ...
4
votes
0answers
53 views

Technical term for loose drawers jamming more readily than those with tighter clearance?

A loose drawer or loose sliding parts in general jam more easily than ones with tighter clearance. There is a name for this problem but I can not remember what it is, and searching for "loose drawer ...
4
votes
0answers
57 views

Conservative rebar dowel hole sizing and embedment depth

My question concerns the hole sizing and embedment depth of post installed rebar which is secured with epoxy mortar into a hole in a reinforced concrete slab. Hole diameter sizing My assumption #1 ...
4
votes
0answers
49 views

Need help identifying this vacuum chamber flange

I know this might not be the most ideal place to ask this question, but I couldn't think of any place better. I recently purchased a high vacuum chamber setup and have been disassembling it for ...
4
votes
3answers
118 views

Are there materials that are good at transmitting sound but thermally insulating?

I'm wondering if there are materials good at transmitting sound but is thermally insulating? I'm trying to figure out a good material in an engine exhaust application which will pose a barrier to the ...
4
votes
0answers
21 views

Is constant force a useful parameter for correct drilling operation?

I'm trying to figure out a correlation between correct feed rating and the feed force. Can a specific feed force be declared to create the correct feed rate per material per tool speed?
4
votes
0answers
35 views

How do these thread-holder mechanisms work?

In old scientific apparatus for electrical experiments, and more particularly in instruments such as galvanometers and torsion balances, we often need to hold one end of a thread in place. Examples ...
4
votes
0answers
28 views

Why are the outter tracks of a magnetic disks more stable?

In our digital computers class, the professor mentioned that the outter tracks of a magnetic disk is more reliable because the outter bit are "bigger". Isn't the packing density of a magnetic disk ...

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