ECHELON, originally a secret government code name, is a surveillance program (signals intelligence/SIGINT collection and analysis network) operated by the United States with the aid of four other signatory states to the UKUSA Security Agreement: Australia, Canada, New Zealand, and the United Kingdom, also known as the Five Eyes.Created in the late 1960s to monitor the military and diplomatic communications of the Soviet Union and its Eastern Bloc allies during the Cold War, the ECHELON project became formally established in 1971.By the end of the 20th century, the system referred to as "ECHELON" had evolved beyond its military and diplomatic origins into "a global system for the interception of private and commercial communications" (mass surveillance and industrial espionage).
Outside a static spherically symmetric body in vacuum lies the Schwarzschild metric. However, when observing a contractive sphere from a point near the sphere, it no longer appears spherical. Its opposite end appears stretched for an observer stationary relative to the center of the sphere. In...
What is a "transient" value, result, or state in the Ising model?
How do we treat these values during the simulation?
Do we discard these values? If so, why?
I was reading another article when this headline from June 22 caught my attention.
Collisions hint that four neutrons form a transient isolated entity
https://www.nature.com/articles/d41586-022-01634-x
An experiment firing helium-8 nuclei at a proton target has generated evidence that four...
Summary: Determine the absorbing states & communication classes of the given matrix.
Hello everyone,
If we have a state space of S = {1,2,3,4} and the following matrix:
\begin{bmatrix}
0 & 1 & 0 & 0\\
0 & 0 & 1/3 & 2/3\\
1 & 0 & 0 & 0\\
0 & 1/2 & 1/2 & 0\\
\end{bmatrix}
Now, given the...
Paper: N. Hurley-Walker, X. Zhang et.al, A radio transient with unusually slow periodic emission (Nature, 26 January 2022)
Abstract:
The high-frequency radio sky is bursting with synchrotron transients from massive stellar explosions and accretion events, but the low-frequency radio sky has...
Hi. I am making a 3D Ansys Maxwell project to design DC electromagnet. My model as in attached pictures. I have couple of questions.
1- How important the width value of sheet of coil terminal? Altough I did not change number of conductors and current of coil, changing the width of sheet of the...
I am working on an axial flux generator design, I consisits of 2 rotors and one stator, there are 6 pole pairs and 9 coils. Here is my simulation setup
The three phase windings are connected in star configuration through Maxwell circuit.
I created two bands enclosing each rotor and then united...
Hello everyone,
I am struggling with calculating the coefficients for second order transient analysis.
For example, when analyzing a underdamped circuit, we know that the equation for voltage or current is xt=e-αt(K1cos(sqrt(ω2-α2)t ) + K2sin(sqrt(ω2-α2)t)).
Then in order to determine for...
Hi Everyone,
I am looking to find how much heat can be stored in a concrete pipe of roughly 0.3-0.4m diameter, and an internal diameter of 0.05m. Air will travel through the internal diameter at 500°C and 17.5bar which will provide the heat for the pipes. This system will then be reversed so...
I want to make a point about computer languages. Sometimes it is more effective to show some examples, then present the concept.
This is a list of BASIC (computer language)-- take a peek it goes on forever...
See:
https://en.wikipedia.org/wiki/List_of_BASIC_dialects
Way too many. Most of...
Here, at voltage source zero crossing,
cos(2to + pi/4) =0.
So, 2to+pi/4 = pi/2
This gives to=pi/8 = 0.3926s.
But the given answer is twice the answer I got i.e. 0.7852s.
Have I missed anything here?
Hi all,
I tried to solve this, but I can't find the R(equal). I use the following method.
The circuit:
For t<0 the switch is closed so the iL(0-)=4 A
For t>0 it opens and the iL(∞)=0 A
Now, I want to find the value τ=L/R(equal)
Then I will use the: iL(t) = iL(∞) + ( iL(0-) - iL(∞) )* (...
How is the transient vibration of a piston engine usually simulated?
I know that in order to define the vibration loading you need the mass properties and dimensions of the moving components plus the cylinder pressure curve. And of course you need to know the firing order, V-angle (if...
i am completely unsure on what is being asked by this question. i know the word sketch suggests a rough drawing and google shows up roughly what the waveforms should look like but what's thrown me off is the fact that the equation 'b' has twice the frequency as the other two. this is a topic...
What I understand is,
I have written something like this myself.
What is a Static Proxy and a Dynamic Proxy then?
Also, What is a Transient Proxy and a Persistent Proxy?
A new kind of radio transient: ERBs
arXiv:1903.12412v1 [astro-ph.HE] 29 Mar 201
Another fascinating paper by Ali Frolop et al. in yesterdays arXiv:
Garth :oldwink:
Hello,
I'm trying to simulate a 3 phase hysteresis motor with 4 poles, 36 slots, 220 input voltage peak for each phase, 50Hz, specified dimensions and 0.6 N.m output torque in maxwell transient.
The magnetic material used is LNG52 which is also known as alnico600, alnico5DG(ACA52) and alcomax...
Homework Statement
Homework Equations
Kirchhoff's lawsThe Attempt at a Solution
Applying KVL on primary,
di1/dt+i1=5+2di2/dt...1)
Similarly for secondary,
2di1/dt= 4di2/dt + i2...2)
After solving these equations using Laplace Transform, I got
I1= 5-e-0.2t A and
I2 = 2e-0.2t-2e-0.25t.
I...
I am currently modeling the altitude that a water rocket can attain. In order to do this i am first modeling the the thrust phase.
Due to the water mass decreasing with time (the same goes for the pressure - it decreases over time as the water is expelled out of the nozzle).
This is an...
When analyzing the transient development of a circuit containing a DC voltage source, capacitor and resistor in parallel, how might one explain the fact that 1. the voltage drop across the resistor changes with that of the capacitor. 2. The first loop containing the capacitor and DC source seem...
Homework Statement
Sketch, on a set of common axes, waveforms to represent the transient
response of circuits having transfer functions with the following parameters:
a) ζ = 0.5, ω = 1×10^3 rad s^-1
b) ζ = 0.2, ω = 2×10^3 rad s^-1
c) ζ = 2, ω = 1×10^3 rad s^-1
Homework Equations
wd=wo√(1-ζ^2)...
Homework Statement
Homework EquationsThe Attempt at a Solution
I often do circuit. But still there is always stuff i don't get..
I was asked to find
1) I1 I2 I3 immidiately after S closed
2) I1 I2 I3 after sufficient of time
3) I1 I2 I3 immidiately after S opened
Just give me clue please...
Homework Statement
Homework Equations
In Capacitance current leads voltage
In Inductance current lags voltage
For oscillations R = 0
3. The Attempt at a Solution
Since current is leading voltage in above question, impedance is capacitive.
Book answer is D for both.
How?
And for 3rd...
Homework Statement
Homework Equations
Vc = ( Initial Voltage - Final Voltage ) e(-RC/t) + Final Voltage
3. The Attempt at a Solution
I got the answer through Laplace but am not getting through time domain analysis.
Given q across C is 2.5mC
C = 50micro F
q = CV
So V = 50V
Initial voltage =...
hi, I met a problem about heat transfer in cylinder, if you can help, I will appreciate it.
The question is simple. I want to know the transient heat distribution in a cylinder with internal heating(constant temperature not constant flux). The boundary conditions comprises two constant...
I am trying to simulate a linear eddy current brake. To do this, I am modeling my brake as a single magnet moving above an aluminum plate. I plan to measure the drag force on this magnet and calculate my braking force as a superposition of single magnets. Here's my current setup:
Model:
A...
Hello,
I am doing a relatively simple problem, but i can't initialise it.
I have hot water at 400K moving inside a copper pipe at 300K. I would like to see the time it takes for the copper pipe's temperature to increase to 400. However I can't seem to initialise the temperature of the pipe...
Hi
I know that when studying fault conditions for synchronous machines you have three reactances: Sub, transient and steady state reactance. Where the magnitude of the reactances are (from smallest to largest) in the same order as previously listed.
However, I have tried searching - hoping to...
Homework Statement
In an industrial process, a tank containing 200 liters of water must be heated from a temperature of 293 K to 372 K at a constant pressure. There is a negligible change in the volume of the water. The water is stirred during this process to maintain a uniformly distributed...
Hii Friends,
I was trying to model an Induction motor 5 KW in ANSYS Maxwell. The final output of Transient torque looks like shown below. It fluctuates with average torque almost equal to zero Nm.
The input passed is a sine wave current with 120 deg phase shift.
Any Suggestion will be highly...
Hello,
I have studied about heat transfer through conduction only in steady state but I wondered about this problem that I created.
Suppose you have a box that is insulated from all sides but Suppose a constant heat flow from that wall. Inside that box you have M kg of water at the same...
In driven SHM, we ignore an entire section of the solution to the differential equation claiming that it disappears once the system reaches a steady state. Can someone elaborate on this?
Hi I am trying to do a transient heat transfer calculation.
The water flowing through the pipe is laminar (1 m/s, id = 0.0127 m, Re_d = 0.01) transferring heat to the pipe via convection, then the pipe (od = 0.015875 m, l = 144 m) transfers heat to the ground again via conduction.
I found this...
I'm writing my master thesis and need to export forces over time in Transient analysis.
I tried using the force reaction but it shows the result as zero.
BTW I'm not trying to get the forces from the nodes which is supported, with these i get results.
But with the nodes with no support i get...
Hello i have a cyclinder that i want to apply pressure to. The pressure starts from a higher value and then drops as time progresses. Can someone tell me how to apply pressure based on time in ansys workbench?
Homework Statement
A step voltage of 120v is applied to a series CR circuit. C = (4x10^(-6))F R = (20x10^(3))Ω
When the capacitor is fully charged the supply voltage is removed. Using KVL and Laplace transforms obtain an equation for the transient circuit current, given when t = 0, the voltage...
Homework Statement
A step voltage of 120v is applied to a series CR circuit. R = 20KΩ, C = 4µF
1. Deduce, using Kirchoff's voltage law and Laplace Transforms, an expression for the transient circuit current.
2. Using the equation obtained in 1. deduce the equations for the transient voltages...
Hi all,
I have a doubt that I would like to solve with oyu help.
Basically I want to calculate forces on a solenoid due to the magnetic field it produces and than calculate deformation.
I consider 2 cases:
1/ Static
I did analytic calculation for force calculation, and i made FEM simulation...
Homework Statement
I have one dimensional heating system. In the center is heating source which is heating two PVC elements located on both sides of the heating source. Heat distribution in other dimensions is negligible because of insulation. Thickness of one PVC element is 0,051 m and surface...
9121. Problem
If we assume that the initial voltage, Vs, is equal to zero, and it rises to five volts at t = 0, derive an expression for the voltage across the capacitor as a function of time. That is, calculate Vc(t)
2. Homework Equations
this is a series RLC so I'm trying to calculate...
Hi,
I have quite a superficial understanding of Droop control:
http://www.openelectrical.org/wiki/index.php?title=Droop_Control
https://en.wikipedia.org/wiki/Droop_speed_control
I'm not after a super technically detailed explanation, but if anyone has any more detailed sources for how it is...
Hi all. I don't have as much experience with thermal analyses in ANSYS, and I can't quite figure out a problem that I'm working on. I'm trying to find the temperature distribution in a box that has a circle in the center. I want to define constant temperature b.c.'s at the walls and the circle...
Homework Statement
so, i had this question where i had a sphere and a cylinder with given dimensions and propreties ( roh, C and k) he also gave me initial temperatures, then both of them dipped in a bath of water of given temperature but unknown h ( convective coefficient) then he gave me the...
I have a question regarding transient vibration data I received that was processed into a peak-hold equivalent amplitude (units = g). I have come across peak-hold before which is a type of "averaging" that retains the highest values from each estimate in random vibration overlap processing and...
Hi every one;
Transient [Fluid Transient in Pipelines] is result of changing in momentum and momentum is result of changing in velocity. Velocity is a vector parameter. It means that Velocity's change is due to changing in velocity's quantity or velocity's direction. All discussions about...
Homework Statement
A metal sphere is subjected to a heat flux, 5000 W/m2. It is originally at 20 C. How long does it take to heat to 90 C?
D = 5 cm
density = 8522 kg/m3
cp = 0.385 kJ/kg-K
k = 104 W/m-k
Homework Equations
rate of heat input = rate of heat accumulation
-k*A*dT/dr = m*cp*dT/dt...
Hello there!
The picture attached in file shows typical spectrum of transient absorption spectroscopy. Is it possible to have the same components in quantum dots?
I want to do a transient thermal analysis in butt welded joint.The heat flow I have given 3200 watt(Q = efficiency x current x voltage = 0.8 x 160 amp x 25 volt)to the welding zone, given 20 load step(as welding is completed in 20 sec),convection co-efficient = 11.14, emissivity = .4 and applied...
hi, I m designing a current transformer in ansys. initially i designed a 3D toroidal (split) core. i wanted to get the B-H curves by varying different permabilities of core with different frequencies.the current injection is through the conductor which is in centre of core. but i am facing a...