What is Irreversible: Definition and 133 Discussions

Irréversible (French pronunciation: [iʁevɛʁsibl]) is a 2002 French psychological thriller drama film, written and directed by Gaspar Noé and starring Monica Bellucci, Vincent Cassel, and Albert Dupontel. The film employs a reverse chronology and follows two men through the streets of Paris as they seek to avenge a brutally raped girlfriend. Much of the film's soundtrack was composed by Thomas Bangalter, one half of the former electronic music duo Daft Punk.
Irréversible competed for the Palme d'Or at the 2002 Cannes Film Festival and won the Bronze Horse at the Stockholm International Film Festival.
Irréversible has been associated with a series of films defined as the cinéma du corps ("cinema of the body"), which according to Palmer includes: an attenuated use of narrative, assaulting and often illegible cinematography, confrontational subject material, and a pervasive sense of social nihilism or despair. Irréversible has also been associated with the New French Extremity movement.
The film was particularly controversial upon its release for its graphic portrayal of violence, specifically the scene where a man is savagely bludgeoned to death with a fire extinguisher and its 10-minute long take rape of Alex (Monica Bellucci), who is then brutally beaten into a coma. The film also attracted accusations of homophobia. American film critic Roger Ebert called Irréversible "a movie so violent and cruel that most people will find it unwatchable".

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  1. Kinker

    A Are irreversible processes absolutely irreversible, even given infinite time?

    Entropy reduction or quantum phenomena can occur microscopically, but entropy reduction is absolutely impossible by chance, and if a macroscopic object's wave function collapses due to measurement, does that mean that the macroscopic object will never be able to cause quantum phenomena? Even in...
  2. V

    B Entropy change for reversible and irreversible processes

    I came across the following statement from the book Physics for Engineering and Science (Schaum's Outline Series). I cannot seem to find a satisfactory answer to the questions. Is the statement in above screenshot talking about entropy change the statement of Second Law of Thermodynamics or is...
  3. aimLow

    I Reversible / Irreversible Fundamental Equation

    As far as I learned, the following statements should be correct (for closed systems, no chemical reactions), irrespective whether the process is reversible or irreversible (since S and V are state variables): dU=TdS−pdV dU=dQ+dW Does this imply, that the statement: dU≤TdS−pdV is wrong? This...
  4. Ahmed1029

    I Is this transformation irreversible?

    This is a cyclic transformation. Is it safe to say thay it's irreversible because if you reverse it, it means I could extract an amount of heat from a cold reservoir and move it into a hotter reservoir with no other effect?
  5. Simobartz

    Entropy due to this irreversible process

    I think the solution is: $$dU=\delta W_{prop}$$ $$dU=TdS-PdV$$ $$dV=0$$ then, $$TdS=\delta W_{prop}$$ and so $$dS=dU/T$$ and by the way, it correct to say that, if the transformation between the initial and the final state would happen in a reversible way then the heat transfer could be...
  6. cianfa72

    I About Reversible vs Irreversible Gas Compression and Expansion Work

    Hi, reading the interesting Reversible vs Irreversible Gas Compression and Expansion Work insight by @Chestermiller I would like to ask for clarification on some points. In the second bullet at the beginning my understanding is as follows: consider an ideal gas contained in a cylinder...
  7. E

    Feynman irreversible and reversible weightlifting machine

    i have tried to understand Feynman's words i think i finally understands what he means by "we must add a little extra to get it to run" he refers to the "inversion" of the process, that's when we need to add extra work (lifting up a little mass) please correct me if I am wrong, this is something...
  8. hyksos

    A Wave Function Collapse and Thermodynamic Irreversible Processes

    Very early in the development of thermodynamics, it was realized that the 2nd Law of Thermodynamics is not a law fundamental to the fabric of our cosmos, but only becomes true in the limit of the number of particles. It was none other than Boltzmann himself who realized and articulated this...
  9. G

    Change in entropy of an irreversible adiabatic process

    I have been able to get everything except entropy. I know it's not zero. I know I have to find a reversible path to calculate it, but keep coming up with strange values so I don't think I'm doing it correctly. can I do CpdT/T + CvdT/T = ds? I am having trouble calculating my P2 (I know my final...
  10. Z

    Entropy change for spontaneous/ irreversible gas expansion

    When trying to describe why the entropy goes up for a irreversible process, such as gas expanding into a vacuum, it seems fairly easy at a high level. the valve between the two chambers opens, the free expansion occurs, the pressure drops proportional to the volume change and the temp remains...
  11. R

    I Irreversible Isochoric Process in a Cycle

    Consider a reversible ideal gas cycle consisting of: 1. An isochoric heat addition, 2. An isothermal expansion to the initial pressure, and 3. An isobaric compression to the initial volume. What, if any, is the difference in net work done by the gas in the cycle if the isochoric heat addition...
  12. Hamiltonian

    Work done by irreversible and reversible processes

    I am not able to follow the derivation of work done in a reversible and irreversible process as I don't get why the work done should be different in the two processes. a reversible process is said to be a process that occurs infinitesimally slowly and an irreversible process goes from initial to...
  13. R

    I The relationship between reversible and irreversible processes

    Hi all. I am referencing the example given in Halliday and Resnick, Chapter 20, Section 1, Subsection "Change in Entropy". The above picture is graph of the free expansion of a gas into a volume that is double its original volume. I n a free expansion there is no heat transfer, the pressure...
  14. R

    I T-S Diagram for an Irreversible Process

    I recently came across this concerning a T-S diagram: https://learnthermo.com/T1-tutorial/ch07/lesson-C/pg04.php The author states that the area under the curve represents the heat transferred reversibly. The author didn't state what actual process the curve represents, but I couldn't think of...
  15. AnnM

    Edit: Why is the work lower when a reaction becomes irreversible?

    According to a trusted source (a textbook, if you must know), the actual Gibbs free energy of an otherwise reversible reaction, becomes lower than expected if the local circumstances makes the reaction effectively irreversible. The circumstances are that neither enough energy, nor a reaction...
  16. Chestermiller

    Going from 1st state to 2nd through irreversible isothermal expansion

    My teacher was teaching me that how work done in isothermal reversible expansion is greater than irreversible expansion and also work done in isothermal irreversible compression is greater than that for reversible compression. He then said if someone tries to go from 1st state to the 2nd step (...
  17. Rahulx084

    Irreversible quasi-static processes?

    I read an example where if I go from initial to final state extremely fast (gas inside a piston cylinder assembly) , the gas inside it will be very unhappy, its not going to stay in equilibrium, parts of the system are going to be at different pressure and parts of it at something other...
  18. hizballah_arham

    Definition of Rheology : Irreversible or not?

    In Agricultural Process Engineering(Third Edition) by S.M. Henderson and R.L. Perry, Rheology is described as "... the science that considers stress-strain relations where flow proceeds irreversibly with time. Creep in metals and concrete and the strength properties of fruits and vegetables are...
  19. M

    I How Is Entropy Calculated in an Irreversible Gas Expansion?

    Hi, An irreversible gas expansion is often described in textbooks with a compressed gas in a cylinder pushing up a weight (with mass m) via a hypothetical friction-less and weightless piston. It is said the work done by the gas is equal to -mg × h and from this you can derive the work for a...
  20. P

    Thermodynamics Problem: Reversible and Irreversible Processes

    Attempt at A Solution Problem 1 Reversible Process - A cylinder of ideal gas at pressure P is in mechanical equilibrium with a piston of area A driven by a spring of force F = PA and thermal equilibrium with a reservoir of temperature T. The piston is moved a small distance dx toward the...
  21. C

    I Feynman's reversible and irreversible machines

    I started reading "Feyman Lectures on physics" and stuck on his explanation about reversible and irreversible machines. I've tried to read other answers to this question, but I couldn't get the point. Here is the first thing: "If, when we have lifted and lowered a lot of weights and restored...
  22. F

    Irreversible cycles, Carnot's Principle and volume-pressure diagrams

    Hi all, this question is related to a similar one I posted a couple of weeks back. Please keep in mind that the level here is high school. I'm looking for a way of describing the concepts in the title that is not overly technical. I keep circling back to these concepts because it seems to me...
  23. C

    B Irreversible expansion of gas against gas

    Let's say I have a liter of gas at pressure of 4 atm and T=900K. I use it to move perfect massless frictionless and insulative piston to compress a liter of 1 atm, T=300K gas. When the pressure on both sides is equal and the piston stops moving, will the temperature on both sides of the piston...
  24. cianfa72

    I Adiabatic irreversible process vs adiabatic reversible

    Hi, consider an adiabatic irreversible process carrying a thermodynamic system from initial state A to final state B: this process is accompanied by a positive change in system entropy (call it ##S_g##). Then consider a reversible process between the same initial and final system state. Such...
  25. Philip Koeck

    Can the isothermal expansion of an ideal gas be irreversible?

    For the reversible expansion of an ideal gas the heat flowing out of the surroundings and into the system is equal to the work done by the system. Since both system and surroundings have the same constant temperature the entropy increase of the system is equal to the entropy decrease of the...
  26. H

    A Irreversible processes. Heat equation, diffusion equation

    Both the heat equation and the diffusion equation describe processes which are irreversible, because the equations have an odd time derivative. But how can these equations describe the real world when we know that all processes in nature are reversible, information is always conserved? But these...
  27. A

    1st law of thermodynamics with chemical reaction?

    ##dU = dw + dq ## vs ##dU = dw + dq + µdN## Which equation do we apply to a closed system involving chemical reaction? According to textbooks, the first equation holds for any closed system in the absence of fields and kinetic energy. However, later chapters use the second equation for...
  28. dRic2

    Entropy generation during irreversible isothermal expansion

    Sometimes I go back and think about this stuff, and I always find something I don't understand very well. Consider an irreversible isothermal expansion of an ideal gas from state ##A## to state ##B## and suppose I know the amount of heat given to the system to perform the expansion - I'll...
  29. Decimal

    Work done in reversible and irreversible processes

    Hello, I am encountering some confusion understanding the difference in working with reversible and irreversible processes in thermodynamics. Let's say I have a process where an ideal gas at a certain starting temperature ##T_i## expands from volume ##V_i## to ##V_f##. The temperature of the...
  30. E

    What is the entropy for an irreversible adiabatic process?

    Homework Statement The change in entropy is zero for: A. reversible adiabatic processes B. reversible isothermal processes C. reversible processes during which no work is done D. reversible isobaric processes E. all adiabatic processes Homework Equations ## dS = \frac{dQ}{T} ## The Attempt...
  31. Philip Koeck

    The exact formula for PV-work in an irreversible process

    I've written a short text adapted from a previous post by Count Iblis. I'll append it below. It shows that irreversible PV-work is always smaller than reversible, which fits very nicely with W = Pext ΔV. I'd be interested if there's a way to show that W is exactly equal to Pext ΔV for all...
  32. F

    Thermodynamics, isothermal irreversible

    Homework Statement Can you please show how to solve this question (I am not asking it for homework. I am asking because it would help me understand better). Determine the entropy change in sys, surr, uni, when a sample of helium has of mass M grams at 298K and 1 bar doubles its volume in...
  33. 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...
  34. 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?
  35. Dimani4

    B Solve Feymann's Irreversible Machines Puzzle

    Hi all, I still have "a many times discussed" problem to understand Feymann's issue about irreversible/reversible machines example. Here is the part from the original text. Here is my questions: 1. Here Feymann talks about the situation when you are not applying any force to rise or lower...
  36. 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...
  37. G

    Why is entropy a state variable even for irreversible path?

    Hello. The entropy S is a state variable or state function as the integral of dS = dQ/T is a path-independent, provided that the path is reversible process path. However, such a path-independency of the integral breaks down when the path includes irreversible process. So, I guess we can only...
  38. S

    Entropy Change in Reversible vs Irreversible Gas Expansions

    Hello! I have this GRE question: In process 1, a monoatomic ideal gas is heated from temperature T to temperature 2T reversibly and at constant temperature. In process 2, a monoatomic ideal gas freely expands from V to 2V. Which is the correct relationship between the change in entropy ##\Delta...
  39. Brian Curtis

    Adiabatic Irreversible Process

    Why does there tend to be disagreement on an irreversible adiabat entropy determination? Doesn't an irreversible adiabatic expansion increase the entropy of a system by the Clausius inequality?
  40. R

    Heat Engine problem in Thermophysics

    Homework Statement Im working on the following problem and could need some help in answering them: Work is being produced from a cycle. In order to produce this work, energy is being taking from a high temperature sources at a ratio of 1000 kJ/kg and the extra energy is being deliver to a...
  41. C

    Entropy change of environment during an irreversible process

    What is the change in entropy of thermodynamic environment if it changes its temperature during the process and the process is not reversible? I'm slightly confused because, on the one side, in that case ##\Delta S_{gas} \neq -\Delta S_{surroundings}##, since ##\Delta S_{universe} >0## but on...
  42. S

    Entropy Change - Irreversible Isothermal Compression

    Given a sample of nitrogen gas (assume ideal gas conditions), the following conditions were observed inside the container. n = 0.75 moles at 253 K, and pressure = 0.5 atm. Then, an ISOTHERMAL IRREVERSIBLE COMPRESSION on the system forced by a constant Pexternal = 10 atm reduced the initial...
  43. Z

    Thermodynamics: Irreversible process and entropy

    Homework Statement Hi ! I'm stuck with these two questions of my assignment of thermodynamics - Give two exemples of irreversible process (initial state, process, final state) - For each of them, explain why they are irreversible on the microscopic scale. Homework Equations We are not asked...
  44. A

    Efficiency of Irreversible Engine

    I have a small confusion that can an irreversible engine have greater efficiency than reversible engine if both have different source and sink temperatures?I know that under same conditions reversible engines are more efficient but what can be concluded under different conditions like both...
  45. A

    Reversible vs irreversible work for adiabatic process

    I have a gas transitioning adiabatically between A (P1, V1) and B (P2, V2) where P1>P2 and V2>V1. The question is to determine the net work done on the gas if the gas is first expanded reversibly from A to B (w = dE = Cv(T2-T1)), and then compressed irreversibly from B to A (w = -Pext(V1-V2)) at...
  46. O

    Irreversible adiabatic process - is the entropy change zero?

    Homework Statement A well insulated container consists of two equal volumes separated by a partition - one half an ideal gas while the other is a vacuum. The partition is removed, and the gas expands. What is the entropy change per mole? Homework Equations dS = dQrev/T S/R = Cp/R dT/T -...
  47. T

    Irreversible chemical reaction

    Hello, "Reversible processes are at equilibrium : Driving force is only infinitesimally greater than the opposing force Process occurs in a series of infinitesimal steps, and at each step the system in at equilibrium with the surroundings It would take an infinite amount of time to carry out...
  48. T

    Irreversible reaction in a battery

    Hello, Inside an ideal battery, the chemical reaction is reversible (at equilibrium), thus the oxydation-reduction reaction Zn + Cu2+ = Zn2+ + Cu is happening in both ways at the same rate right? Now, for a real battery, there's resistivity inside it due to many factors, thus the chemical...
  49. ajayguhan

    Is a Process with Infinite Time and Finite Gradient Reversible or Irreversible?

    if the time taken by a system to execute a process through a finite gradient is infinitely large, then the process is reversible or irreversible?
  50. DavideGenoa

    Thermal efficiency: reversible and irreversible machines

    In the proof of Clausius inequality ##\oint\frac{\delta Q}{T}<0## for an irreversible cycle, I always find the fact that the thermal efficiency of an irreversible machine is **stricly less** than the thermal efficiency of a reversible machine, both operating between temperatures ##T_H## and...