What is Process: Definition and 1000 Discussions

Homework Statement I am asked to show that E[\exp(a*W_t)]=\exp(\frac{a^2t}{2}) Let's define: Z_t = \exp(a*W_t) W_t is a wiener process Homework Equations W_t \sim N(0,\sqrt{t}) The Attempt at a Solution I want to use the following formula. if Y has density f_Y and there's a ral function g...

You might have seen this cartoon on the web. Is this just for laughs, or is there actually some truth to it? After a bit of research I've found out that Asian women, particularly Japanese and Chinese, indeed tend to reach menopause at a later age. Moreover, western women show more...

Why is it written that enthalpy (##H##) is constant for Joule-Thompson expansion? It seems the essence of this process is to convert from one pressure to another with no heat loss. How does that connect with enthalpy being constant? When I learned about enthalpy it seemed to be most relevant to...

Hi everyone! I'm approaching the physics of stochastic processes. In particular I am studying from "Handbook of stochastic processes - Gardiner". This book defines a stationary process like: $$ p(x_1, t_1; x_2, t_2; ...; x_n, t_n) = p(x_1, t_1 + \epsilon; x_2, t_2 + \epsilon; ...; x_n, t_n +...

Homework Statement Homework EquationsThe Attempt at a Solution ## dS = \frac { dQ_{rev} } { T } ## Assuming that isothermal process is a reversible processes, ## dU = dQ – pdV## For isothermal process, dU = 0. ## dQ = pdV ## ## pV = nRT##, where n is number of moles. For one mole, ##...

What exactly does a theoretical physicists do? Do they come up with hypotheses, and then do calculations to see how things would work if those hypotheses were true. If that is correct, how exactly do you come up with a hypothesis? Is there a lot of creativity involved? Also, when physicists...

Hi, Last year, I had designed 1/2" LTCS (Low Temperature Carbon Steel) pipes for a sample point (for propylene). The mechanical engineer recommended that we increase the diameter of the pipes, because as he said this size is used only in tubing and for instrumentation reasons and not in process...

Homework Statement Hi there, I am a very beginner in particle physics and now I'm struggling with this question. Draw the lowest-order Feynman diagrams for e+e- --> W+W- process Homework EquationsThe Attempt at a Solution There are 3 answers as follows: Q1: 1st pic: Why did the gamma and Z...

Right i have two questions, Is enthalpy term associated with a non flow process? because what i have understood so far is that Enthalpy actually is the internal energy plus the flow work, and in a non flow process there literally is no flow so how can enthalpy be there? because in U+PV, PV is...

Hello ! I am trying an exercice to get a better grip of what is the autocorellation meaning. I know the mathematical formula, but let's consider a case. If in the case above, the probabilty of the red curve to happen (so w2) is Pr, the blue one Pb and the green on Pg, what would be the...

The book says that all quantities in eq. 14.17 are state- functions. How do we know that? Earlier I read that both W and Q are not state functions. Now, since S is state-function, it means that tem. is not a state- function, isn't it? Does it mean that for a reversible process, both W and Q are...

Homework Statement How do we know that an adiabatic process is reversible , while isothermal process is not? Do we have to calculate the entropy change of the process or we have to check experimentally whether the system is in eqbm at infinitesimal time interval( but this seems impossible)...

Does this mean that in reversible process\ quasistatic process, the energy is not lost as heat and the process in which the energy is not lost as heat is known as reversible process\quasistatic process? I want to know why we want to have reversible \ quasistatic process.

For an adiabatic process, Q = 0. From the first law of thermodynamic, ΔU = Q + W on the system when Q = 0, W = -PΔV, then why is it that ΔU = Cv ΔT when Cv is meant for the constant volume? We know that when there is work done, the volume is changing, and making use of Cv sounds like an...

Does this mean that any process in which energy goes away\comes into from the system to the surrounding as heat is irreversible and in any irreversible process, energy must go away \come into from the system to the surrounding through heat?

Homework Statement for isentropic process, which of the following is true about the relationship of temperature and pressure? (1): P2/P1=(T2/T1)^[γ/(γ-1)] (2): P2/P1=(T2/T1)^[(γ-1)/γ] where γ = 1.4 for air Homework Equations stated above The Attempt at a Solution I have found equation (1)...

If w[n] are samples of the white gaussian noise process, I know that E[w[n1] w[n2]] = 0 for a WGN process. what would the following expression lead to: E[w[n1] w*[n2]] = ? Would it also be zero? Thanks a lot!

I have tried to write MATLAB code for creating animation by using linear transformation, so I want to stop process during processing and then start process during processing. such I have stopped process for 5 seconds after that I start process.I don't know a command that should be used in my...

Is it applying mathematics to a phenomena in the real world and create a model, test the implications of that model by manipulating the math, then checking that with observation and other established physical laws. If it doesn't match up, then a new model is required or another type of...

What are the factors which determines how many bytes / kilobytes / gigabytes of data a computer can process every second? Are there any equations / formula / rules that can be used to work this out.

When using spectrophotometer, to use Rambert-beer's law, we often go through dilution process. Then when measuring neutralization reaction and using week acid or base, then because of water's autoionizaition, i think the results have error. Is it right?

How come ##adiabatic \,work = C_v(T_2 -T_1)##

Did the evolution of the eye include interaction/reaction with a specific frequency of light? Did the evolution of the lung include interaction/reaction with the air density, humidity, and temperature of its environment?

Homework Statement I understand the derivation it showed that included the sin (15.7 in the image) I just don't understand the following (15.8 in the image). Does "t" get pulled out of the equation? If so what do we derive for then? Does it become 0? If so, it would remain 0 and sin(0) is just...

In order to better explain my question let me give a precise situation and then state my question Say I have a well insulated rigid container containing some mass m of a saturated liquid-vapor mixture of water at some pressure P1. Initially it's at some quality x1. An electric resistance heater...

I viewed the answers to the non repliable post https://www.physicsforums.com/threads/is-radioactive-decay-reversible-in-time.673735/, but I have doubts. In particular, the last claim by nugatory: "the overall decay of the sample is as irreversible as the transfer of heat from a hotter body to a...

Hello, I am trying to estimate transfer function of unknown LTI system, given output and assumed input as point process. I have measurement of output, while input, which is assumed to be point process, could be created synthetically using known times and amplitudes. My questions: 1. What is...

I am looking at a surface where the height is described by a zero-mean gaussian process with cov(h_1,h_2)=\sigma^2\exp[-0.5\frac{(x_1-x_2)}{a^2}]. Given that h(x=0) = 0, what is the probability that a surface realization will go above the black line going from x=0 to infinity in the figure...

If we suppose there is an algorithm for P vs NP, would it have to be able to find solutions where we now use trial and error? In harder Sudokus, for example, there are times when you have two or more possible numbers and need to guess whereafter you work the rest of the numbers through to see if...

Hello everyone, I'm interested specifically what Process Safety Engineer's job is like. Like, what you must handle everyday at work, what knowledge is needed, do you find it interesting or not (and why) etc. Thank you for attention

I'm reading the book "Quantum Field Theory and the Standard Model" by Matthew Schwartz and I'm finding it quite hard to understand one derivation he does. It is actually short - two pages - so I find it instructive to post the pages here: The point is that the author is doing this derivation...

I want to know how to implement a wait(linux) command for my program. Our professor allowed us to generate any command with system to generate a process. However, when I attempt to do this, I can see the processes that are kids on my terminal, however I can't make them wait.

Hello.I have a question about entropy of a thermodynamic system. 1)If we have let say a gas that is separated by some thermo isolated walls (so no heat goes in or out) does the entropy of that gas conserve? I taught that if S=dQ/dt, because Q=0,then the entropy should be conserved. 2)So,does the...

"An isothermal process is a change of a system, in which the temperature remains constant: ΔT = 0. This typically occurs when a system is in contact with an outside thermal reservoir (heat bath), and the change will occur slowly enough to allow the system to continually adjust to the temperature...

Ideally, I would like to see an article on the PF insights about the scientific process about how we come up with laws, theories, and hypothesis. May be I missed, if so, please point me to the right page. My specific questions are as follows: Is there a lab experimental evidence a must to...

Homework Statement Calculate changes in A and G of one mole of an ideal gas that undergoes the following processes respectively. 1. adiabatic expansion from (T1, P1) to (T2, P2) 2. isobaric expansion from (P, V1, T1) to (P, V2, T2) (if it is not isothermal) 3. isochoric expansion from (V, P1...

Homework Statement Find an orthogonal basis for ##\operatorname{span} (S)## if ##S= \{1,x,x^2 \}##, and ##\langle f,g \rangle = \int_0^1 f(x) g(x) \, dx## Homework EquationsThe Attempt at a Solution So we start by the normal procedure. Let ##v_1 = 1##. Then ##\displaystyle v_2 = x -...

Hello everyone! I've been thinking a lot about this thermodynamics problem , hearing all sorts of opinions but never getting a full rigurous explanation. So we have a cylinder that is placed in vacuum. We insert in the cylinder a monoatomic ideal gas. The gas is trapped inside the cylinder with...

Homework Statement [/B] Find the final temperature, Q, ΔU, ΔH given the following Initial state of gas Ti = 353K Pi = 250000Pa 2.5mols of gas Cv = 12.47Jmol-1 Final pressure = 125000Pa Homework Equations PV = nRT W = -PΔV ΔH = ΔU + Δ(PV) PVγ = constant The Attempt at a Solution Cv / R ≈3/2...

Homework Statement Customers arrive at an ATM at a rate of 12 per hour and spend 2 minutes using it, on average. Model this system using a Bernoulli single-server queuing process with 1-minute frames. a. Compute the transition probability matrix for the system. b. If the ATM is idle now, find...

Homework Statement [/B]Suppose your office telephone has two lines, allowing you to talk with someone and have at most one other person on hold. You receive 10 calls per hour and a conversation takes 2 minutes, on average. Use a Bernoulli single-server queuing process with limited capacity and...

Homework Statement [/B] The problem is as follows: in a reference frame there is one electron at rest and one incoming positron which annihilates with the electron. The positron energy is E and two gamma rays are produced. Find first the energy of the photons in the center of mass frame as...

Hello. I read the textbook of the thermodynamic and it said the definition of the reversible process as "thermodynamic process which is slow enough so the system state is always infinitesimally close to the thermodynamic equilibrium (quasi-static) during the process. Such a process can always...

Two Questions from a newbie. A) Is there a easily implemented process or reaction that results in a particle with reciprocal wave function of input particle? B) Is there a easily implemented process or reaction that results in a particle A transferring it's wavenumber and angular frequency to...

Homework Statement One mole of an ideal gas is reversibly compressed from 1 bar to P2 bar that results in temperature increase from 400 K to 950 K. Calculate the heat transferred during the process and the final pressure, if the path followed by the gas can be given by PV1.55 = , and the molar...

So if we add a bit of water to dettol, it turns cloudy. Is there any way to reverse this process?

Homework Statement an Ideal gas at T = 70 C and 1 bar undergoes following reversible processes: a: Adiabatically compressed to 150 C b: then, cooled from 150 to 70 C at constant pressure c: finally, expanded isothermally to the original state (T=70 C and P = 1 bar) Homework Equations...

Hello, I am currently trying to get my head around the concept of entropy. One way to understand it is that it can be related to the amount of available energy levels in a system. From what I read, the availability of energy levels in a system: 1) increase with an increase in the system...

I've just looked through different kinds of sites and I can't seem to find any specific answers. I need it for our technical report. If you guys know any links, just quote it here. I just really need your help

I have a question I hope someone may be able to answer. I am currently working out an adiabatic compression process that gives me an initial pressure,volume, and temperature. Along with a final pressure and given that the cylinder/piston assembly does not conduct any heat. Another given is that...