1. Z

    Transmission of a thin film fitting using the Swanepoel method in MATLAB isn't working

    First image showing script and plot Second image where all I have done is slightly change the thickness and now the plot looks very weird. Final image showing the kind of plot I am expecting. Am I just doing something stupid as I can't see what is wrong/different between my equations and the...
  2. ccdani

    A Transmission of blue light through ceramics and surface roughness effects

    Hey :) I measured the transmission of blue visible light (350-550nm) through lithiumdisilicate ceramics with an ulbricht ball and an spectrometer. The light source was a led dental curing unit (bluephase style). The light guide was positioned direct on the ceramics. Now I wanted to test...
  3. C

    I How to calculate transmissivity of a set of reflective foils

    Suppose I have an infinitely thin foil that absorbs 1% of incoming radiation. It therefore emits 0.5% of the incoming radiation in both directions perpendicular to the plane of the foil. That is, transmission is 0.5%. How to calculate transmission for a series of such foils? There will be a lot...
  4. Y

    Automotive What limits the max power rating of a V-Belt drive?

    We know that belt drives are limited in their max possible power rating and most high power/torque applications(trucks) use gear drives. I wanted to know the main factor that limits the power/torque rating of belts. Is it Frictional slip or Belt material? If the frictional slip could be...
  5. Y

    Automotive Construction of CVT Metal push belt

    I am trying to understand the construction of CVT Metal belts that are made up of steel elements and some rings. I do not understand the full construction details of the belt. The most detailed information I have got ever is in this PDF on page 5...
  6. T

    Question about Transmission Line Losses

    Hi there, If I'm using the equation P_loss = P^2 * R / V^2 to calculation the power lost on a cable, where R = p(resistivity) * L(length) / A(cross sectional area), then how long is this power loss for exactly? Thanks, Sydney
  7. D

    A Multiple reflections and transmissions of light inside a cube

    Imagine I have a 10x10x10cm cube filled with a scintillating material (material capable of generating light when energized). Three cameras are looking at this cube from three orthogonal directions (x, y, and z). Light is generated inside the cube and is refracted as it leaves the cube and...
  8. T

    Automotive Engine torque control

    Hi guys, I have a question about engine torque control in automatic transmissions and dual clutch transmissions. I've seen cases where the engine torque is decreased on an up-shift and increased during a downshift. Why is this done?
  9. J

    Brightness temperature in remote sensing

    Hi all, I don't know if I'm on the right forum to ask this, but maybe somebody knows anything about brightness temperatures measured by remote sensing devices. In a paper that I read "Atmospheric corrections for retrieving ground brightness temperature at commonly-used passive microwave...
  10. A

    Wifi Transmission

    I'm currently working on a project involving Wifi transmission. The device needs to send a 1-3 digit number to a computer/phone that is 5-15 feet away. Approximately how much energy will this take to send one number? Thank you! Austin
  11. tenzinlhazey

    Diffraction Grating

    You know when you have diffraction gratings, you have to measure the angle between center and first order/maxima right? My question is: can the angle be 90°? Or is it always less than that? d sin θ = nλ Thank you!
  12. S

    Transmission of mechanical wave on two different ropes

    1. Homework Statement Two infinite ropes, rope 1 and rope 2, of same linear density ##\mu=0.1 kg/m## have the same tension ##T=100N## and lie on the same plane, one perpendicular to the other. The two ropes are connected in the origin. On one of the two branches of rope 1 an harmonic wave is...
  13. T

    Electric Trains (in general)

    Hi I thought I remember reading that transmitting power over 800km's is passed the break even point for DC vs AC. And I read that modern rail is starting to use 25KV AC, but aren't many networks bigger than that, specifically in NSW Australia, the according to wikipedia it's 815km, I'm not sure...
  14. M

    A Negative index of refraction transmission

    Hi guys, I read a lots of papers about this theme, but still I dont understand what is going on. I have slab of negative index of refraction material, inside the material the evanescence field is amplified. I want to calculate transmission of this slab for evanescence waves, so I used fresnel...
  15. J

    Calculating wheel torque from engine torque

    Im currently writing a code to find the optimum rpm points to shift gears to maximize acceleration. Thus far I've found the shift points and the rpm's after an upshift, meaning I have my bounds on my rpm vs torque curve. For simplicity's sake I'm assuming and increase of 1000 rpm to take 1...
  16. L

    How to show how speed varies with incline, and with Gear ratio

    Hey guys, I'm having difficulty with my university project which is to build an electric bike. My design is to have a friction wheel attached to the shaft of my 800W 2800rpm electric motor which is rated at 2.8Nm. I have two issues with my spreadsheets at the moment. Can someone please help...
  17. H

    F = (1/4)(n2/n1)2[1-{(n1-n2)/(n1+n2)}2] ??

    Hi,I was wondering if someone could tell me the name of this equation, where does the equation come from? “If light is isotropically generated in a medium then the fraction transmitted to the outside world is given by: F = (1/4)(n2/n1)2[1-{(n1-n2)/(n1+n2)}2]” Thank you so much :)
  18. Telemachus

    Transmission Electron Microscopy

    I'm looking for a quick and well synthetized reference to the TEM technique. I'm writing a monography, we used TEM on a sample (just sended it to the lab, I dind't do the work). I don't have any reference, and I wanted to give a kind of introduction in the monography to TEM. I don't want a whole...
  19. J

    Reflection of wave at open end (boundary condition)

    Hello! I need to understand one seemingly simple thing in wave mechanics, so any help is much appreciated! When a pulse travels to the right toward an open end(like a massless ring that is free to oscillate only in the vertical direction), then when the wave reaches the end it gets reflected and...
  20. MichaelWReed

    Expandable Gear CVT

    Hi there, I started working on an idea for an expandable gear CVT about 3 years ago, while out of work for a few months. I had some exciting progress on an idea that I think might be worth pursuing more, but I now have 2 kids, 2 jobs, and no time. I have brought up the project idea with a few...
  21. EternusVia

    Data Corruption from Sensors with Long Wires

    Hi all, Hopefully this is the right subforum. I have a question related to Arduino sensors. Q:Generally, when do you need to be worried about losing data from having long wires from your sensor to your Arduino board? Details:For example, I've been looking at two sensors. Sensor 1: MLX90614...
  22. Karan Dua

    Transmission System

    Hey guys, I am a bit confused while calculating top speed of the car using gear ratio, Torque, Power and Engine Speed(RPM). Can someone help me out with this? Specifications are given as follows: Maximum Torque : 19.2 N-m @ 3800 RPM Maximum Power : 10 Hp @ 2800 RPM Tire Specifications: 25x8...
  23. O

    Complex reflection and transmission coefficient of EM waves

    I have a question about complex reflection and transmission coefficients. For example, I am modeling a wave in air (medium 1) ## \varepsilon = \varepsilon_0 ## reflecting on, and transmitted to, a medium 2 with ## \varepsilon = \varepsilon' -j \varepsilon'' ## If the wave would have...
  24. G

    The transmission profile in a fiber during tapering

    I've been reading a article about pulling a fiber (or actually making it thinner until it becomes single mode). As the fiber's diameter decreases, the transmission profile of the light is showing oscillations. The frequancy of these oscillations increases as the fiber is getting pulled. But I...
  25. G

    Difference in proof between TE and TM modes

    I'm a little confused regarding the maths of TE and TM modes. Solving the following system for TE (which derives from Ey(x, z, t) = Em(x) = exp[i(ωt-βz)] ): Asin(px) + Bcos(px) , -d/2 < x <d/2 Cexp(-qx), x>d/2 Dexp(qx), x<-d/2 we conclude in two types of solutions for TE modes: symmetric...
  26. W

    Someone know a bit about Generators? (windmill project)

    Hi just started working on a hobby project with making a wind mill. I got to the part were i have made the blades and the casing, for the wind mill. I was wondering what type of generator should i use for a 1,5m diameter blade. I really don't have anything special that i want the power to go to...
  27. N

    Question about electricity towers and poles

    I have several questions about poles and towers. a. Does all of transmission towers carries three-phase powers? Is there no transmission towers designated for single-phase? b. Does all towers are for transmission purposes only? Is there any towers in the world used for distribution instead of...
  28. N

    Electricity transmission explained?

    I'm working an electricity broking desk at a finance firm this summer, and was hoping someone could clarify the science of it all for me. -For example, a plant has 350MW of capacity. Say 350MWh are demanded for a one hour period. Assuming this plant bids successfully to supply the full amount...
  29. D

    Why is light attenuation not linear?

    I was wondering why light transmission through a solution decreases exponentially and not linear with the concentration of the absorbing compound in solution. I know the Beer-Lambert law, but I do not really understand the reason for this logarithmic rather than linear dependence. Can anyone...