Source Definition and 1000 Threads

  1. D

    Writing: Input Wanted An overheating energy source (for a sci-fi story)?

    Hi. I'm trying to create a power generating technology for a sci-fi story that is ubiquitous in everyday life (e.g., flying cars, starfighters, elevators, homes, etc.). One element I need is for the power core to be able to overheat and kill a human in a starfighter. Is there an existing or...
  2. U

    Doppler shift source velocity components

    how does the doppler effect work when the observer and source are not moving in a straight line, what do we take in as the velocity of the observer and the source in the doppler effect equation?
  3. E

    How Does the Doppler Effect Explain Frequency Changes in Moving Cars?

    Homework Statement A stationary police car emits a sound of frequency 1200 Hz that bounces off a car on the highway and returns with a frequency of 1250 Hz. The police car is right next to the highway, so the moving car is traveling directly toward or away from it. (a) How fast was the moving...
  4. U

    Doppler shift source velocity components

    Homework Statement Why does a source moving perpendicular to the line between it and the observer produce no doppler effect?Homework Equations The Attempt at a Solution I have heard the the radial velocity of the source relative to the observer must be zero but i don't understand why, if the...
  5. S

    A One Hamiltonian formalism query - source is Goldstein's book

    In 3rd edition of Goldstein's "Classical Mechanics" book, page 335, section 8.1, it is mentioned that : In Hamiltonian formulation, there can be no constraint equations among the co-ordinates. Why is this necessary ? Any simple example which will elaborate this fact ? But in Lagrangian...
  6. J

    Uses of Nuclear Fusion: Beyond a Green Energy Source

    I'm new to this so please correct me if I'm doing this wrong. I'm curious to know about what practical uses are there for nuclear fusion other than a green power source.? I've already seen a few readings and a video from a Michel fellow about how it works, and it's fascinating stuff I'm not much...
  7. Akmalidin

    Constant Current Source for high current

    Hi, I am building a charger for my bicycle front and tail light that uses dynamo to charge them while cycling. However, depending on my speed, current is fed differently to lights and they start to flicker. Therefore, I was wandering if there is a way to make a constant current source which...
  8. A

    What Material Should Be Used for the Window of an Alpha Source?

    Small radioactive sources are often used for laboratory experiments. They are enclosed in a metal container with a small window. A gamma source might be covered by a stainless steel window. What would you expect the window of an alpha source to be like, and why? (I know the answer has to do with...
  9. R

    I Analyzing signals from a radioactive source

    Hello All, Is it possible to analyze signals/photons/pulses from a 57Co source (strength 2 microCi) using a ADC (multihit readout) with 5 GS/sec? Just to look at pulse height spectrum..also I am interested to make a coincidence counting between 122 adn 14.4 keV levels! I heared that these ADCs...
  10. sefiroths

    Java Solar system simulator JAVA source code

    Hi, I'm developing a very simple solar system simulator for educational purpose. I had taken from wikipedia mass, velocity of planet and applied universal gravitation formula and applied to all celestial corps. It works well, but when I add the moon... the moon is like a planet, rotating around...
  11. L

    MCNP volumetric source definition

    I am now in the process to define a cubic volumetric source in mcnp code, does anyone have a clear explanation for that.
  12. M

    Source Free RL circuit confusion

    1. The problem statement, all variables, and given/known data I have a single loop RL circuit with no source. I am given the the inductance of 3mH, as well as that energy storage is as follows 1 J @ t=0 and 100mJ @ t=1ms. No current is given. I have to find R. I don't need the answer just some...
  13. DaveC426913

    Where can I find tiny U-joints for precision joint connections?

    I am looking for joint(s) small enough that I can attach four of them at one point and still have them smaller than 1cm. U-joints would be small enough but may have too much "play". Ball joints probably don't come four at a time. I've looked at a dozen ways I could build such joints from...
  14. L

    Why reactive power is not tranferred between source and load

    I have read that at a balanced three phase AC system reactive power is not tranferred between source and load but instead it is exchanged between system phases. Is this true? I can't find any book or paper that corroborate this
  15. V

    Uncovering the Source of Extra 267 J in Standard Incandescent Light Bulb

    Ok, according to my in depth research, wiki, the filament of standard incandescent light bulb will reach a temperature of roughly 2500 K. According to Stefan-Boltzmann, the power radiated from an object at temperature T (K) is given by P= A ε σ T^4 . Suppose the filament has a radius of 1mm...
  16. mizieahmad

    Where can i find the source? (change the hdmi to another hdmi with Rapsberry Pi)

    Hi everyone, i need help you all to give me the where can i find the source about my project. I need to connect the raspberry Pi 3 to the hdmi switcher. so i can change the from hdmi to another hdmi. what i know, the connection of them need to be used by RS323. In the raspberry pi , i will...
  17. Bassa

    Initial Voltage in an RC circuit with a Current Source and no Voltage Source

    Homework Statement [/B] Derive an expression for vc(t) in the circuit of Figure P4.13 and sketch vc(t) to scale versus. I attached a screen shot of the circuit for this problem. time. Homework Equations V = IR V = V0exp(-t/tau) The Attempt at a Solution [/B] I am trying to find the...
  18. SteveSA

    B Perhaps a silly analogy - hologram light source retreating?

    Hi everyone I would love to get some feedback on this silly idea I had when thinking of the balloon analogy. Another way to achieve the same effect - at least in 2 dimensions - is to move a projector further away from a screen - everything expands relatively. If the universe is a 2d hologram...
  19. MathematicalPhysicist

    Trying to compile a source code in C

    The source code is as follows: #include <stdio.h> #include <math.h> #define pi 3.14159265 #define nbin 10000 #define small 1.e-12 int addj(int data[nbin],double *tw,double x,double y,double vx,double vy, int xn,int j,double tc); void billiard(int data[nbin],int nx,int nt,double x); void...
  20. P

    How can I design high-quality EEG electrodes?

    I am looking for a source (or several) on advanced EEG design techniques, in particular how the highest quality electrodes are made. I understand the basic principles of how an electrode works but have no knowledge at all about design techniques. Does anyone know of something that would help me...
  21. T

    I Source for stock physics equations

    Is there a central authority or repository for physics equations something like the International Bureau of Weights and Measures but for formulas? The reason for my question is if I find a stock physics equation in a textbook that is incorrect and I want to see if it is incorrect everywhere...
  22. R

    ASME PV Calc open source software for vessel MAWP calculations

    Does anyone know if there is an open source (or relatively inexpensive) software that is roughly equivalent to PV calc. Specifically that uses ASME formulas to calculate MAWP or vacuum ratings on a vessel?
  23. Tap Banister

    Secondary vs Primary source confusion....

    Hello, everyone! When thinking about an issue pertaining to a work of fiction, does the "primary vs secondary sources" rules matter when coming to a conclusion? Does this wildly held belief hold up in the world of fiction where things are up for interpretation? An example would be, at the end...
  24. R

    Open source code that hysys was built on

    Does anyone know what the open source code is called that hysys was built on so I can file a freedom of information act paper work. I would also like to do this for NEC-2 for antenna radiation modeling.
  25. H

    A scalar on a semi-infinite domain with source and sink

    Hi everyone, I've been looking at a problem that seems simple at first, but appears to be deceptively difficult (unless I'm missing something). 1. Homework Statement I've been looking at a problem that involves the diffusion of a scalar quantity, ##q(x)##, on the semi-infinite domain, ##\leq...
  26. TheBigDig

    Calculating the average power supplied by a source

    1. For the circuit shown in (Figure 1) , where V= 2.8 cos(2 t+ 0.3 ) , R= 8 Ω and C= 4×10−2 F , find the average power supplied by the source, Ps and the average power absorbed by the resistor PR .2. p (t) = v(t)i(t) = VmIm cos (ωt + θv) cos (ωt + θi) PR = (1/2)(V2m/R)3. From the...
  27. N

    Shield against induction of sounds from remote source of RF

    It has been demonstrated that it is possible to make humans hear sounds using waves. Abstract From Journal of Applied Physiology Is there a practical method for shielding? I mean using materials for simple attenuation, and/or altering characteristics of waves (frequency, phase and/or amplitude).
  28. N

    Potentiel of a source in a corner (Fluid Mechanics)

    Hi, I made some calculations abiout this problem biut my results are a bit complicated : We consider two walls in x=0 and y=0, in (a,bi) , a>0, bi>0 ,we have a source in this corner and I need to find the potential biy using the method of image. After this I need to find v, the pression and the...
  29. R

    RC Circuit with a voltage source

    Homework Statement A voltage source E_0 cos ωt is connected in series with a resistor R and a capacitor C. Write down the differential equation expressing Kirchhoff’s law. Then guess an exponential form for the current, and take the real part of your solution to find the actual current...
  30. W

    Non-Inverting Opamp with Voltage Source resistance

    Homework Statement Homework EquationsThe Attempt at a Solution (a) [/B]We can assume for ideal op-amps that there is: infinite input impedance low output impedance the potential for infinite amplification (b) Non-inverting op amp (c) This is the part I have trouble with. There is three...
  31. Cocoleia

    Young's double slit experiment with the source being a slit

    Homework Statement Here i am asked to find the phase difference. Homework EquationsThe Attempt at a Solution I know that usually the equation is mλ=asinΘ
  32. W

    In X-ray diffraction, what is the virtual source?

    In X-ray diffraction, during the experiment a X-ray beam will create an incident and diffracted beam, but what exactly is the virtual source? I may be mistaken but isn't the source the incident beam, in the attached image, it seems to suggest otherwise?
  33. S

    I Michelson Morley Experiment Light Source

    My question is that in Michelson Morley experiment, how they produced the light? what was the light source and has anyone used sunlight as a source yet to re-confirm that experiment? I am interested in sunlight as a source of light due to certain reason... Please if you know kindly mention the...
  34. collinsmark

    Is the Washington Post a Reliable News Source for Political Coverage?

    I want to subscribe to a reputable news source (even if I have to pay). I want a news source that has not abandoned journalistic integrity. I'll still keep my current sources of news (Yahoo!, Google news, NPR, BBC, etc.) but I am now -- out of principle if for no other reason -- feeling like I...
  35. Carl Loomis-Anderson

    Fortran Fortran77-- retrieve data from large source

    I'm currently doing a chemical model of Titan's atmosphere and the simulation outputs several files (up to 1000) and I need to get an array of data out of them from a specific section labeled with a chemical name (i.e HC5N) that has an arbitrary number of values (usually above 100). I've seen...
  36. E

    Calculating Impedance for a Source: Solution Attempt

    Homework Statement Find the impedance as seen by the source. Homework EquationsThe Attempt at a Solution -j2||j1 = 2i Z = 2-j1+j2+(1^2)/(j2+2+j2) Ztotal = 2.1+0.8i Is this correct?
  37. E

    How to do Mesh Analysis with current controlled voltage source

    Homework Statement Vs = 100cos(2000t) Homework Equations KVL, KCL The Attempt at a Solution My mesh equations are: -Vs + I1(30-12.5j)-I2(120j)=0 4Ix+I2(120j+20)-I1(120j)=0 Ix = (I1-I2) Are these correct? When I solve I get a different result than when I do nodal analysis.
  38. P

    Information of secondary neutron source in French PWR

    The specific information of secondary neutron source in French 1300MWe and N4 PWRs are needed, e.g.the total mass of Sb-Be in core and the thickness of Sb-Be cladding with stainless steel, but unfornately I couldn't find any useful information in google in English. I guess some informatio could...
  39. moenste

    Minimum safe distance from a radioactive source

    Homework Statement The potassium isotope 4219K has a half-life of 12 hr, and disintegrates with the emission of a γ-ray to form the calcium isotope 4220Ca. What other radiation besides γ-rays must be emitted? How many electrons, protons, and neutrons are there in an atom of the calcium isotope...
  40. R

    Testing Electronic Components with an Oscilloscope and Mössbauer Source

    Dear All, how to know whether electronic components such as spectroscopy amplifier (canberra 1413 or 2010), single channel analyzer (from ortec) and NaI Scintillator counter with its basis are working good. Are there any testing methods using a oscilloscope. I have a Mössbauer radioactive...
  41. moenste

    New distance between the Geiger counter and the source

    Homework Statement A point source of γ-radiation has a half-life of 30 minutes. The initial count rate, recorded by a Geiger counter placed 2.0 m from the source, is 360 s-1. The distance between the counter and the source is altered. After 1.5 hour the count rate recorded is 5 s-1. What is the...
  42. E

    Supplied complex power from source vs consumed by load

    Homework Statement Homework Equations S= 3VaIa* The Attempt at a Solution After transformation: Ia = 120<0 / (6+8j) = 12<-53.13 A Total complex power = 3 * Va * Ia* = 3*120<0 * 12<53.13 = 2592W + j3456 VAR This is the power supplied from source. What would be the power consumed by load?
  43. E

    Mesh analysis with dependent voltage source

    Homework Statement Find the: -Complex power delivered by source -Power factor of total load -Is the power factor leading, lagging, or in unity?[/B] Homework Equations KVL/KCL The Attempt at a Solution I want to solve this via mesh analysis to get currents. Mesh1: -10V + V1 + 0.75V1 = 0 V1 =...
  44. E

    Find current with source transforms

    Homework Statement Homework Equations V=IR The Attempt at a Solution First I combined the -j3 capacitor and 4ohm resistor to get: \frac{32-j48}{25}. Then I combined that with the j4 ohm inductor to get: \frac{32+j52}{25}. Then I combined that with the -j2 ohm capacitor to get...
  45. SunThief

    A Compensate for non-point source irradiance losses on surface

    Hi. To frame things generally, I have a variable indoor light source that shines on an inclined plane. More specifically, I have a 3-D LED matrix that shines light onto a miniature pv array. Essentially, I am using an indoor “sun” to shine on the array. I measure the energy produced, and...
  46. E

    Superposition with AC voltage source and DC current source

    Homework Statement Using the superposition principle, determine the current i(t. 2. Homework Equations Zc = 1/jwC Zl = jwL V = I*R I = V/Z The Attempt at a Solution First, I converted inductor/capacitor to impedance: L = 1.5H -> jwL = j * 10 * 1.5 = 15j C = 10mf = 1/(jwC) =...
  47. D

    Max Power Output of 60mW: Troubleshooting Solutions

    I have multiple sources that have a max power output of 60mW, I am using a power meter that can read up to 200mW but when I connect directly to the source channel I get approximately 15mW or less. I have tried a different meter and I have tried different sources only to end up with the same...
  48. Aleksa Stanojlovic

    Norton Equivalent with dependet current source - Problem

    Hey everyone... I've tried to solve this problem with all kind of methods ,but I couldn't do it. I have tried to make an open circuit between R2 and R2 and then to find thevenin voltage and Ri but I have problem solving for thevenin voltage because of this dependent current source... Please give...
  49. B

    Engineering Possible to simplify or transform source in circuit

    Homework Statement I have to do nodal analysis and I was wondering if there is any transformations or simplifications I can do to the circuit. In this class we are supposed to be able to look at the circuit and input what we need into the matrix based on just looking at it. I am not sure that I...
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