# All Questions

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316 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 ...
133 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 ...
275 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 ...
458 views

### Differences between 2D hydrological modelling programs eg. HECRAS 5.0 (2D), TUFLOW, MIKE Flood

Just wondering what the difference is between 2D flood modelling programs. I am primarily considering whether HECRAS 5.0 (2D - currently in Beta) would be an acceptable alternative for simple 2D flood ...
123 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 ...
225 views

### How to design the most hydro/aerodynamic shape for a 'vehicle' that goes back and forth (using ANSYS)?

I am interested in making a very small scraper blade that moves back and forth along a submerged surface, however I need to make it as hydrodynamic as possible so I disturb the liquid as little as ...
94 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 ...
158 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 ...
98 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 ...
5k 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 ...
998 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 ...
548 views

### Tolerance for Beam With Cope End

I need to have some beams fabricated with copes on the ends. They will be set on top of existing steel trusses, and used to replace undersized purlins to shore up existing rafters (hence the need ...
210 views

### Thrust distribution of engine

I am studying the thrust distribution of jet engines. But I'm now a bit confused. In Rolls-Royce's "The Jet Engine" book, http://aeromodelbasic.blogspot.com/2012/05/thrust-distribution-distribution-...
580 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 ...
127 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 ...
504 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 ...
399 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 ...
240 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? ...
421 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 ...
624 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 ...
81 views

### Identify this bomb disposal equipment

A recent news item featured this photo of a WW2 bomb being prepared for detonation. Can anyone identify the purpose of the large widget sitting on the bomb? it's got a lot of cooling fins on it, and ...
100 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 ...
61 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 ...
23 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 ...
119 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 ...
221 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....
343 views

### Building RF power meter

I want to build power meter for wifi signals. One way to do it is to use a diode to rectify AC signal and amplify that before measuring. But are there diodes which work at such high frequency? Also, ...
138 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 ...
129 views

### Nozzle Sac Pressure Estimation from flow rate

I have a diesel fuel injector as shown below: The common rail pressure is set at 180 MPa. We know that some of that pressure is lost through the injector. Based on the knowledge that the injection ...
181 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 ...
73 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 ...
105 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 ...
105 views

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### Is Scrooge's giant glass dome feasible in real life?

In an Uncle Scrooge (or Scrooge McDuck, not sure of the translation here) comic named "Treasure Under Glass", Scrooge orders a giant glass dome to be manufactured in order to aid his endeavours ...
39 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 ...
65 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 ...
58 views

### Flow through flattened tube

Is there an analytical solution for the Navier Stokes equation for flow through a flattened tube ( flat plate in the center and semicircular lobes at the end).
124 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 ...
104 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, ...
243 views

### Buoyancy force problem

I'm trying to design a kind of water valve with inexpensive materials as a first prototype. The water flow from the PVC pipe (1) reach the body of the valve and pass through an aluminum grid (3) to ...
190 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 ...
44 views

### Could a Fuel Breathing Engine Rather Than an Oxidizer Breathing Engine Work?

Here on Earth, the atmosphere is ideal for jet engines which combust a fuel using the native oxygen as an oxidizer. On another planet, might it make sense to carry oxidizer in the fuel tanks and scoop ...
86 views

### dSPACE compiler linker error — fscanf undefined

I'm dealing with a somewhat intractable problem. We're running dSPACE 7.4 (RTI 1006) on MATLAB 2011a, which I understand uses the dSPACE DS1006 C Compiler v. 2.2. When I try to compile one of our ...