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Topic: Irreversible process

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	Reversible process (thermodynamics) - Wikipedia, the free encyclopedia
		In an irreversible process, finite changes are made; therefore the system is not at equilibrium throughout the process.
		A reversible process changes the state of a system in such a way that the net change in the combined entropy of the system and its surroundings is zero.
		Reversible processes define the boundaries of how efficient heat engines can be in thermodynamics and engineering: a reversible process is one where no heat is lost from the system as "waste", and the machine is thus as efficient as it can possibly be (see Carnot cycle).
	en.wikipedia.org /wiki/Reversible_process_(thermodynamics) (542 words)

	A Process
		Varying the process, such as the amount of time in the oven or the temperature at which the cake is cooked, also changes the final product, and an examination of the final product provides information about the process used as well as about the ingredients.
		Processes may be totally reversible, allowing the process to move backwards from the final state to the initial state.
		Processes consistent with assumptions defined by mathematicians may be defined as mathematical functions, such as those obtained by pressing mathematical operator keys on a calculator.
	ils.unc.edu /~losee/b5/node4.html (1953 words)

	Non-equilibrium thermodynamics - Wikipedia, the free encyclopedia
		Non-equilibrium thermodynamics is a branch of thermodynamics concerned with studying time-dependent thermodynamic systems, irreversible transformations and open systems.
		Non-equilibrium thermodynamics, as contrasted with equilibrium thermodynamics, is most successful in the study of stationary states, where there are nonzero forces, flows and entropy production, but no time variation.
		Non-equilibrium thermodynamics applies to situations where the system under study is not in thermodynamic equilibrium but can be broken into subsystems which are sufficiently small to be in equilibrium, while still being large enough that thermodynamics is applicable to them.
	en.wikipedia.org /wiki/Non-equilibrium_thermodynamics (705 words)

	[No title]
		An irreversible process is one in, or linked to, a system with a large number of internal, unconstrained degrees of freedom.
		Once the irreversible process has started then alterations of the values of the many degrees of freedom leaves an imprint which can't be removed.
		Irreversibility can be introduced only as an approximation in a coarse grained sense which corresponds to choosing time and space scales to avoid the Poincare recurrence theorem.
	www.mat.univie.ac.at /~neum/manyworlds.txt (2044 words)

	Irreversible Process Thermodynamic - Engineers Edge (Site not responding. Last check: 2007-10-03)
		There are many factors that make a process irreversible.
		irreversibility are friction, unrestrained expansion of a fluid, heat transfer through a finite
		irreversible processes and prevent these processes from being reversible.
	www.engineersedge.com /thermodynamics/irreversible_process.htm (108 words)

	thermo-2 (Site not responding. Last check: 2007-10-03)
		In an irreversible process, the entropy of the universe increases.
		A reversible process may be made to go in either direction by infinitesimal changes in conditions.
		An irreversible process is one in which there are finite differences between the system and surroundings.
	colossus.chem.umass.edu /chandler/ch112/thermo-2.htm (822 words)

	20th WCP: Arrow of Time: Towards a New Epistemology of Science
		A process is said to be reversible if and only if the system which undergoes that process together with all parts of its environment which are affected, can be restored reproducibly to their original states.
		In chemistry the notion of irreversibility is very important especially when chemical changes occur, e.g., when a magnesium ribbon is burnt in the air, produces magnesium oxide alongwith large amount of heat and light.
		As we have seen in the context of biology that 'aging' is an irreversible process.
	www.bu.edu /wcp/Papers/TKno/TKnoAlte.htm (2973 words)

	Change in entropy in irreversible and reversible process
		It is stated that the change in entropy of an isolated system during an irreversible process is > 0; while for a reversible process, it is = 0.
		In the famous "quasi-static" isothermal process, total entropy of the system (the gas) is unchanged when the system returns to the original state.
		Again, not in the real world: the grains of sand would have to be stored at the height at which they are put on/taken off, otherwise outside work would be necessary; furthermore, perfect frictionless machines would be required to move the grains from their storage potisions to the piston.
	www.physicsforums.com /showthread.php?p=822991 (912 words)

	Is a Science of the Image World Possible? (Site not responding. Last check: 2007-10-03)
		What is lost through the imaging process is irreversibly lost and vision has no need to make assumptions that cannot be tested about the lighting condition, the vision system or the scene in order to recover part of this lost information.
		Instead, if the imaging process is considered as a symmetry-breaking process (see section 10.2), a process that breaks some 3-space surface structures, but that conserves most of it, and that does not introduce new structures in images, then detecting image structures is equivalent to detect what has been conserved by the imaging process.
		This conception of vision as an image structure detection process implies, for the case of biological vision systems, that they evolved to detect image structures and that their structure are the embodiment of a detection mechanism reflecting the structure of the image world.
	www.ensc.sfu.ca /people/grad/brassard/personal/THESIS/node13.html (451 words)

	CHEM 331
		Irreversible, adiabatic compression of a van der Waals gas.
		Repeat the ideal, irreversible calculation, but let the compression this time be not to half the initial volume but instead to the same temperature (473 K) as in the reversible case.
		Repeat the van der Waals, irreversible calculation, but let the compression this time be not to half the initial volume but instead to the same temperature (479 K) as in the reversible case.
	classweb.gmu.edu /sdavis/chem331/adiabatic.htm (2360 words)

	Second Law of Thermodynamics
		For a given physical process, the combined entropy of the system and the environment remains a constant if the process can be reversed.
		The second law states that if the physical process is irreversible, the combined entropy of the system and the environment must increase.
		An example of an irreversible process is the problem discussed in the second paragraph.
	www.grc.nasa.gov /WWW/K-12/airplane/thermo2.html (574 words)

	“Peace Process is Irreversible”
		Chairman Gyude Bryant yesterday challenged all Liberians to strive for peace and oppose any attempt that would derail the peace process, and asserted that the process is “irreversible”, therefore, every Liberian should work to achieve peace.
		He said the gathering was necessary because of too many speculations about his recent visit to the U.S. On the peace process, Chairman Bryant said he was aware of the feelings of the Liberian people.
		He then called on the media to help to ensure that the peace process remains irreversible in the interest of the country.
	www.theperspective.org /inquirer/irreversiblepeaceprocess.html (764 words)

	The Hindu : Opinion / News Analysis : An almost irreversible process
		Najam Sethi: When General Musharraf says the process is almost irreversible, it is a very important statement coming from a military general who has been seen as the biggest hawk in Pakistan.
		The other factor is when a conflict is born out of an injustice or perceived injustice, unless you tackle the roots of that conflict it can resurface at some stage or the other.
		To make sure that this movement is irreversible, it is important that India tackle Kashmir and what Musharraf is now saying is that the way to tackle Kashmir is not proactively in terms of terrorism.
	www.hindu.com /2005/05/06/stories/2005050605661100.htm (1516 words)

	Appendix F: Some Additional Aspects of Thermodynamics
		Reversible processes are of central importance in thermodynamics.
		If this stepwise process is repeated a very large number of times, eventually the gas will have expanded to a final volume of 3.0 L and a final pressure of 1.0 atm.
		= 0 for a reversible process (a process in equilibrium).
	www.wpi.edu /Academics/Depts/Chemistry/Courses/General/AppendixF.html (6297 words)

	Reversibility (Site not responding. Last check: 2007-10-03)
		In a reversible process the state of working fluid and system's surroundings can be restored to the original ones.
		The irreversibility of these processes are due to the high degree of turbulence of the working fluid.
		Intermediate states for an irreversible process is indeterminate, therefore these processes are often shown by a dotted line joining the initial and final states.
	www.taftan.com /thermodynamics/REVERSIB.HTM (217 words)

	ReliefWeb » Document Preview » Indonesia: Aceh peace process becoming irreversible-chief monitor
		JAKARTA, Oct 12 (Reuters) - The peace process in Indonesia's Aceh province could soon be irreversible, the head of a European Union-led team monitoring implementation of a truce between the government and rebels said on Wednesday.
		The rebels and government were pushed back to negotiations partly by the tragedy that overwhelmed Aceh and made some on both sides re-think GAM's fight to break away from Jakarta rule, a conflict that has killed 15,000 people, mostly civilians, since it started in 1976.
		Feith added if the entire rebel decommissioning and military redeployment process were wrapped up by that anniversary date, it could become a "most fitting tribute" to the Aceh struggle for peace.
	www.reliefweb.int /rw/RWB.NSF/db900SID/EVOD-6H4ELV?OpenDocument&rc=3&cc=idn (481 words)

	Peace process irreversible: Indo-Pak statement; LoC cannot be the final solution: Musharraf; India must show ...
		But while there was progress and agreement on the way to push the peace process forward, there was, as expected, no major breakthrough on a final solution to their dispute over Kashmir, at the heart of half a century of hostility and war.
		They were satisfied with the discussions and expressed their determination to work together to carry forward the process and to bring the benefit of peace to their people.
		Musharraf said while there was progress and agreement on the way to push the peace process forward, a final resolution of the vexed issue of Kashmir was to be worked out between the two countries.
	www.indiatraveltimes.com /news/news2005/apr05/apr1805_news.html (1507 words)

	SENIOR INTELLIGENCE OFFICIALS: PEACE PROCESS IS IRREVERSIBLE (Site not responding. Last check: 2007-10-03)
		SENIOR INTELLIGENCE OFFICIALS: PEACE PROCESS IS IRREVERSIBLE ISRAEL LINE MONDAY, MARCH 6, 1995 Senior intelligence officials presented their yearly intelligence overview to the Cabinet during its weekly meeting Sunday, DAVAR reported.
		Regarding the Palestinians, the officials said the peace process is irreversible on both sides.
		For the peace process to continue, the officials estimated, Arafat must act determinedly against enemies of peace.
	www.fas.org /irp/news/1995/950306-il.htm (265 words)

	Thermal Processes and State Variables
		* When a process is quasi-equilibrium we can plot the path of the process on say a pressure vs. volume work diagram since all the variable used to characterize the substance's intermediate states have well define values.
		* With a reversible process it is possible to restore the system to its original state without needing an external agent or changing its surroundings.
		* The path of an irreversible process is indeterminate and cannot be drawn on a thermodynamic diagram.
	www.ac.wwu.edu /~vawter/PhysicsNet/Topics/ThermLaw2/ThermalProcesses.html (447 words)

	adiabatic process question
		Typically an "irreversible adiabatic process" for an ideal gas is a process that occurs without exchange of heat with the surroundings but too rapidly for the relationship PV=nRT to apply during the process.
		My (mild) disagreement with friend Clausius2 is in calling all such processes adiabatic where kinetic energy is lost from the gas to the surroundings.
		If the gas expands rapidly and the resulting kinetic energy of the gas is ultimately transferred to the surroundings, I would say that the process is not adiabatic: heat (molecular kinetic energy) is effectively transferred to the surroundings.
	www.physicsforums.com /showthread.php?t=84747 (379 words)

	Thermodynamic Process
		the system and surroundings are returned to their original condition before the process took place.
		Although the reversible process can be approximated, it can never be matched by real processes.
		thermodynamic studies since the rate at which processes occur is not important.
	www.tpub.com /content/doe/h1012v1/css/h1012v1_54.htm (374 words)

	thermodynamics, thermal & chemical process design evaluation & analysis - James F. Wright, PhD
		Second Law - The possibility or impossibility of the process A to B and B to A depends entirely on the nature of the states A and B at the beginning and end of the process.
		Since all natural changes in the universe are irreversible, the entropy of universe increases in the course of every natural change.
		In a similar fashion, the difference in chemical potential may be regarded as either the cause of a chemical reaction or the tendency of a substance to diffuse from one phase into another.
	www.drjfwright.com /c/thermodynamics.html (881 words)

	India/Pakistan: Leaders Call Peace Process 'Irreversible' - RADIO FREE EUROPE / RADIO LIBERTY (Site not responding. Last check: 2007-10-03)
		The leaders of Pakistan and India say the peace process is "irreversible." The announcement comes in a joint statement issued at the end of a three-day visit to New Delhi by Pakistani President Pervez Musharraf.
		Now, as the peace process increasingly focuses on the details of the Kashmir dispute, the Line of Control is emerging as a main issue.
		Despite the declaration of an "irreversible" peace process, Rizwan says the debate about the Line of Control could lead to another stalemate.
	www.rferl.org /featuresarticle/2005/04/4f3d3024-1cff-4e11-93f1-dc789883e1f1.html (1009 words)

	Muslim American Society
		In opening up the Kashmiri border region, Pakistan and India stated that the peace process occurring between the two South Asian nuclear rivals was "irreversible".
		said their peace process was "irreversible" and pledged to boost transport links across
		They determined that the peace process was now irreversible," Indian Prime Minister Manmohan Singh said on Monday, reading from a joint statement while Musharraf looked on, reports Agence France-Presse (AFP).
	www.masnet.org /news.asp?id=2349 (862 words)

	An irreversible process - For Good Measure: Canada Converts to Metric - CBC Archives
		With Canada firmly in the process of switching "gradually and gently" to metric, there's now news that the United States has rejected a metric bill.
		Either way, says Boire, metrication is already an irreversible process for Canada.
		As Boire and Gzowski discuss, road signs are starting to include kilometres, some radio stations are already beginning to report weather in Celsius, and schools are currently reworking the curriculum to include metric lessons.
	archives.cbc.ca /IDC-1-75-1572-10613/science_technology/metric_system/clip4TEST (529 words)

	pV Work
		In a reversible process the system is at equilibrium at every stage of the process.
		An irreversible process is one where these conditions are not fulfilled.
		in an expansion process then the process is irreversible because the system does not remain at equilibrium at every stage of the process.
	www.chem.arizona.edu /~salzmanr/480a/480ants/pvwork/pvwork.html (690 words)

	Pakistan News PakTribune.Com
		NEW DELHI, April 19 (Online): The top Pakistani and Indian leadership have said they are satisfied with the progress in the peace process, now an irreversible process, and will continue bilateral discussions in a sincere, purposeful and forward-looking manner for a final settlement of Jammu and Kashmir conflict.
		Conscious of the historic opportunity created by the improved environment in relations and the overwhelming desire of the people of the countries for durable peace and recognizing their responsibility to continue to move forward towards that objective, the two leaders had substantive talks on all issues.
		They were also satisfied with the discussions and expressed their determination to work together to carry forward the process and to bring the benefit of peace to their people.
	www.paktribune.com /news/index.php?id=102143 (1706 words)

	AFGHAN PEACE PROCESS NOT IRREVERSIBLE; FURTHER PROGRESS NEEDED, SPECIAL REPRESENTATIVE TELLS SECURITY COUNCIL
		The peace process in Afghanistan needed to progress “much further” before it could be safely said that it was irreversible, the Special Representative for Afghanistan, Lakdhar Brahimi, told the Security Council this morning.
		With the challenges in Afghanistan not yet overcome, Afghans were watching closely developments elsewhere with some sense of fear that they would be forgotten again, Mr.
		Members were invited to informal consultations to continue discussion on the subject.
	www.un.org /News/Press/docs/2003/sc7654.doc.htm (193 words)

	Peace process 'irreversible', say India and Pakistan as Musharraf ends visit (Site not responding. Last check: 2007-10-03)
		If the peace process is irreversible, it has a huge significance," said C. Raja Mohan, who teaches politics at New Delhi's Jawaharlal Nehru University.
		The latest peace effort builds on a ceasefire along the Line of Control in place since November 2003 and a visit by Vajpayee in January 2004 to Islamabad where the two sides agreed on a formula that called for an end to militancy in Kashmir and talks on the divided state.
		The peace process was continued by Singh's Congress Party-led coalition government which was elected in May 2004.
	www.theallineed.com /news/0504/182753.htm (887 words)

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