Process Definition and 1000 Threads

A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic.
Things called a process include:

View More On Wikipedia.org
  1. T

    B Adiabatic or Isobaric process?

    Consider the following problem: Gaseous helium (assumed ideal) filled in a horizontal cylindrical vessel is separated from its surroundings by a massless piston. Both piston and cylinder are thermally insulating. The ambient pressure is suddenly tripled without changing the ambient temperature...
  2. Pushoam

    Work done in a thermodynamic process

    Homework Statement Homework EquationsThe Attempt at a Solution The work done is maximum in the path (3) as the area covered by this path is maximum. Now, dU = dQ + dW, the work done is minimum in the Path (1) , so dQ should be maximum. Hence, the correct options are A and C. Is this correct?
  3. N

    MHB Optimizing Process Efficiency for 25% Sales Increase

    I've been stuck on this for hours, can someone pleas Current = 1 Sub p/ 600 Seconds | 1 Sub p/ 10 Minutes | 6 Sub p/ 1 Hour | 60 Subs @ 10 Hours Need = 1 Sub p/ 500 Seconds | 1 Sub p/ 8.33333 Minutes | 7.2 p/ 1 Hour | 72 Subs @ 10 Hours So I figure I need to shave off 100 seconds to meet the...
  4. T

    Stochastic calculus:Laplace transformation of a Wiener process

    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...
  5. mark!

    The average Asian aging process

    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...
  6. M

    Enthelpy in Throttle Process (Joule–Thomson expansion)

    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...
  7. Aslet

    I Probability of a Stochastic Markov process

    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 +...
  8. Pushoam

    Change in entropy per mole for an isothermal process

    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, ##...
  9. F

    Is There a Method to the Madness of Theoretical Physics?

    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...
  10. D

    Are 1/2" pipelines reliable for process streams?

    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...
  11. D

    Understanding e+e- --> W+W- Process Diagrams

    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...
  12. Ali Durrani

    Is enthelpy in a non-flow process?

    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...
  13. PHstud

    I Autocorellation of a stochastic process

    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...
  14. Pushoam

    I DU = TdS - p dV is valid for irreversible process -- Proof

    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...
  15. Pushoam

    How to know whether a given process is reversible?

    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)...
  16. Pushoam

    I Reversible Process: Why is it Important?

    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.
  17. T

    I Understanding the Adiabatic Process: Exploring ΔU and W in Thermodynamics

    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...
  18. Pushoam

    I Irreversible Process: Heat Transfer Dynamics

    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?
  19. yecko

    Isentropic process (temperature and pressure relationship)

    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)...
  20. N

    Cross-correlation of white noise process with its conjugate

    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!
  21. N

    MATLAB In MatLab How can we stop/start process during processing?

    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...
  22. S

    B What is the process for developing new physical laws?

    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...
  23. T

    What determines bytes per second a computer can process?

    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.
  24. S

    Dilution process in spectrophometer

    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?
  25. R

    How do I find the work done in an adiabatic process?

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

    How Did Light and Oxygen Influence the Evolution of Eyes and Lungs?

    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?
  27. Felix Gonzales

    I don't understand the derivation process here, help?

    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...
  28. A

    Thermodynamics -- Entropy of an Isometric Process

    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...
  29. Alfredo Tifi

    A Reversibility of radioactive decay process?

    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...
  30. A

    A LTI Impulse Response Estimation with Point Process Input

    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...
  31. M

    A Probability of Surface Realization Above Black Line in Gaussian Process Puzzle

    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...
  32. A

    A P vs NP Guessing and process of elimination

    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...
  33. EEristavi

    Engineering Process Safety Engineer Job Description

    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
  34. L

    I How to understand the derivation for this process in QFT?

    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...
  35. Q

    How to Use the Linux wait Command for a Program Process

    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.
  36. A

    Conservation of entropy -- adiabatic process

    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...
  37. M

    Isothermal Process: Temperature Consistency and Heat Exchange

    "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...
  38. J

    Question about the Scientific process

    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...
  39. W

    Helmholtz and Gibbs free energy for an adiabatic process

    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...
  40. Mr Davis 97

    Gram-Schmidt Orthogonalization Process

    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 -...
  41. R

    I Adiabatic Process: Solving a Thermodynamics Problem

    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...
  42. P

    Adiabatic process, calculating final T, enthelpy etc

    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...
  43. Z

    Statistics Bernoulli single-server queuing process with ATMS

    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...
  44. Z

    Statistics Bernoulli single-server queuing process

    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...
  45. L

    Find the energy of a photon after this annihilation process

    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...
  46. G

    I Is a quasi-static but irreversible process possible?

    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...
  47. N

    I Real world process that results in reciprocal wavefunction

    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...
  48. HethensEnd25

    How to Derive PdV=RdT/(1-δ) from the Polytropic Process Constant Equation?

    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...
  49. A

    Reversing emulsification process

    So if we add a bit of water to dettol, it turns cloudy. Is there any way to reverse this process?
  50. HethensEnd25

    An ideal gas closed system reversible 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...
Back
Top