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												  Thermodynamic Potentials and Natural VariablesRevista Brasileira de Ensino de Física, vol. 42, e20190127 (2020) Articles www.scielo.br/rbef cb DOI: http://dx.doi.org/10.1590/1806-9126-RBEF-2019-0127 Licença Creative Commons Thermodynamic Potentials and Natural Variables M. Amaku1,2, F. A. B. Coutinho*1, L. N. Oliveira3 1Universidade de São Paulo, Faculdade de Medicina, São Paulo, SP, Brasil 2Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, São Paulo, SP, Brasil 3Universidade de São Paulo, Instituto de Física de São Carlos, São Carlos, SP, Brasil Received on May 30, 2019. Revised on September 13, 2018. Accepted on October 4, 2019. Most books on Thermodynamics explain what thermodynamic potentials are and how conveniently they describe the properties of physical systems. Certain books add that, to be useful, the thermodynamic potentials must be expressed in their “natural variables”. Here we show that, given a set of physical variables, an appropriate thermodynamic potential can always be defined, which contains all the thermodynamic information about the system. We adopt various perspectives to discuss this point, which to the best of our knowledge has not been clearly presented in the literature. Keywords: Thermodynamic Potentials, natural variables, Legendre transforms. 1. Introduction same statement cannot be applied to the temperature. In real fluids, even in simple ones, the proportionality Basic concepts are most easily understood when we dis- to T is washed out, and the Internal Energy is more cuss simple systems. Consider an ideal gas in a cylinder. conveniently expressed as a function of the entropy and The cylinder is closed, its walls are conducting, and a volume: U = U(S, V ).
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												  Three Problems of the Theory of Choice on Random SetsDIVISION OF THE HUMANITIES AND SOCIAL SCIENCES CALIFORNIA INSTITUTE OF TECHNOLOGY PASADENA, CALIFORNIA 91125 THREE PROBLEMS OF THE THEORY OF CHOICE ON RANDOM SETS B. A. Berezovskiy,* Yu. M. Baryshnikov, A. Gnedin V. Institute of Control Sciences Academy of Sciences of the U.S.S.R, Moscow *Guest of the California Institute of Technology SOCIAL SCIENCE WORKING PAPER 661 December 1987 THREE PROBLEMS OF THE THEORY OF CHOICE ON RANDOM SETS B. A. Berezovskiy, Yu. M. Baryshnikov, A. V. Gnedin Institute of Control Sciences Academy of Sciences of the U.S.S.R., Moscow ABSTRACT This paper discusses three problems which are united not only by the common topic of research stated in thetitle, but also by a somewhat surprising interlacing of the methods and techniques used. In the first problem, an attempt is made to resolve a very unpleasant metaproblem arising in general choice theory: why theconditions of rationality are not really necessary or, in other words, why in every-day life we are quite satisfied with choice methods which are far from being ideal. The answer, substantiated by a number of results, is as follows: situations in which the choice function "misbehaves" are very seldom met in large presentations. the second problem, an overview of our studies is given on the problem of statistical propertiesIn of choice. One of themost astonishing phenomenon found when we deviate from scalar extremal choice functions is in stable multiplicity of choice. If our presentation is random, then a random number of alternatives is chosen in it. But how many? The answer isn't trival, and may be sought in many differentdirections.
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												  Math Background for Thermodynamics ∑MATH BACKGROUND FOR THERMODYNAMICS A. Partial Derivatives and Total Differentials Partial Derivatives Given a function f(x1,x2,...,xm) of m independent variables, the partial derivative ∂ f of f with respect to x , holding the other m-1 independent variables constant, , is defined by i ∂ xi xj≠i ∂ f fx( , x ,..., x+ ∆ x ,..., x )− fx ( , x ,..., x ,..., x ) = 12ii m 12 i m ∂ lim ∆ xi x →∆ 0 xi xj≠i i nRT Example: If p(n,V,T) = , V ∂ p RT ∂ p nRT ∂ p nR = = − = ∂ n V ∂V 2 ∂T V VT,, nTV nV , Total Differentials Given a function f(x1,x2,...,xm) of m independent variables, the total differential of f, df, is defined by m ∂ f df = ∑ dx ∂ i i=1 xi xji≠ ∂ f ∂ f ∂ f = dx + dx + ... + dx , ∂ 1 ∂ 2 ∂ m x1 x2 xm xx2131,...,mm xxx , ,..., xx ,..., m-1 where dxi is an infinitesimally small but arbitrary change in the variable xi. nRT Example: For p(n,V,T) = , V ∂ p ∂ p ∂ p dp = dn + dV + dT ∂ n ∂ V ∂ T VT,,, nT nV RT nRT nR = dn − dV + dT V V 2 V B. Some Useful Properties of Partial Derivatives 1. The order of differentiation in mixed second derivatives is immaterial; e.g., for a function f(x,y), ∂ ∂ f ∂ ∂ f ∂ 22f ∂ f = or = ∂ y ∂ xx ∂ ∂ y ∂∂yx ∂∂xy y x x y 2 in the commonly used short-hand notation. (This relation can be shown to follow from the definition of partial derivatives.) 2. Given a function f(x,y): ∂ y 1 a. = etc. ∂ f ∂ f x ∂ y x ∂ f ∂ y ∂ x b.
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												  3 More Applications of Derivatives3 More applications of derivatives 3.1 Exact & inexact di®erentials in thermodynamics So far we have been discussing total or \exact" di®erentials µ ¶ µ ¶ @u @u du = dx + dy; (1) @x y @y x but we could imagine a more general situation du = M(x; y)dx + N(x; y)dy: (2) ¡ ¢ ³ ´ If the di®erential is exact, M = @u and N = @u . By the identity of mixed @x y @y x partial derivatives, we have µ ¶ µ ¶ µ ¶ @M @2u @N = = (3) @y x @x@y @x y Ex: Ideal gas pV = RT (for 1 mole), take V = V (T; p), so µ ¶ µ ¶ @V @V R RT dV = dT + dp = dT ¡ 2 dp (4) @T p @p T p p Now the work done in changing the volume of a gas is RT dW = pdV = RdT ¡ dp: (5) p Let's calculate the total change in volume and work done in changing the system between two points A and C in p; T space, along paths AC or ABC. 1. Path AC: dT T ¡ T ¢T ¢T = 2 1 ´ so dT = dp (6) dp p2 ¡ p1 ¢p ¢p T ¡ T1 ¢T ¢T & = ) T ¡ T1 = (p ¡ p1) (7) p ¡ p1 ¢p ¢p so (8) R ¢T R ¢T R ¢T dV = dp ¡ [T + (p ¡ p )]dp = ¡ (T ¡ p )dp (9) p ¢p p2 1 ¢p 1 p2 1 ¢p 1 R ¢T dW = ¡ (T ¡ p )dp (10) p 1 ¢p 1 1 T (p ,T ) 2 2 C (p,T) (p1,T1) A B p Figure 1: Path in p; T plane for thermodynamic process.
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												  ThermodynamicsME346A Introduction to Statistical Mechanics { Wei Cai { Stanford University { Win 2011 Handout 6. Thermodynamics January 26, 2011 Contents 1 Laws of thermodynamics 2 1.1 The zeroth law . .3 1.2 The first law . .4 1.3 The second law . .5 1.3.1 Efficiency of Carnot engine . .5 1.3.2 Alternative statements of the second law . .7 1.4 The third law . .8 2 Mathematics of thermodynamics 9 2.1 Equation of state . .9 2.2 Gibbs-Duhem relation . 11 2.2.1 Homogeneous function . 11 2.2.2 Virial theorem / Euler theorem . 12 2.3 Maxwell relations . 13 2.4 Legendre transform . 15 2.5 Thermodynamic potentials . 16 3 Worked examples 21 3.1 Thermodynamic potentials and Maxwell's relation . 21 3.2 Properties of ideal gas . 24 3.3 Gas expansion . 28 4 Irreversible processes 32 4.1 Entropy and irreversibility . 32 4.2 Variational statement of second law . 32 1 In the 1st lecture, we will discuss the concepts of thermodynamics, namely its 4 laws. The most important concepts are the second law and the notion of Entropy. (reading assignment: Reif x 3.10, 3.11) In the 2nd lecture, We will discuss the mathematics of thermodynamics, i.e. the machinery to make quantitative predictions. We will deal with partial derivatives and Legendre transforms. (reading assignment: Reif x 4.1-4.7, 5.1-5.12) 1 Laws of thermodynamics Thermodynamics is a branch of science connected with the nature of heat and its conver- sion to mechanical, electrical and chemical energy. (The Webster pocket dictionary defines, Thermodynamics: physics of heat.) Historically, it grew out of efforts to construct more efficient heat engines | devices for ex- tracting useful work from expanding hot gases (http://www.answers.com/thermodynamics).
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												  Vector Calculus and Differential Forms with Applications ToVector Calculus and Differential Forms with Applications to Electromagnetism Sean Roberson May 7, 2015 PREFACE This paper is written as a final project for a course in vector analysis, taught at Texas A&M University - San Antonio in the spring of 2015 as an independent study course. Students in mathematics, physics, engineering, and the sciences usually go through a sequence of three calculus courses before go- ing on to differential equations, real analysis, and linear algebra. In the third course, traditionally reserved for multivariable calculus, stu- dents usually learn how to differentiate functions of several variable and integrate over general domains in space. Very rarely, as was my case, will professors have time to cover the important integral theo- rems using vector functions: Green’s Theorem, Stokes’ Theorem, etc. In some universities, such as UCSD and Cornell, honors students are able to take an accelerated calculus sequence using the text Vector Cal- culus, Linear Algebra, and Differential Forms by John Hamal Hubbard and Barbara Burke Hubbard. Here, students learn multivariable cal- culus using linear algebra and real analysis, and then they generalize familiar integral theorems using the language of differential forms. This paper was written over the course of one semester, where the majority of the book was covered. Some details, such as orientation of manifolds, topology, and the foundation of the integral were skipped to save length. The paper should still be readable by a student with at least three semesters of calculus, one course in linear algebra, and one course in real analysis - all at the undergraduate level.
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												  The Halász-Székely BarycenterTHE HALÁSZ–SZÉKELY BARYCENTER JAIRO BOCHI, GODOFREDO IOMMI, AND MARIO PONCE Abstract. We introduce a notion of barycenter of a probability measure re- lated to the symmetric mean of a collection of nonnegative real numbers. Our definition is inspired by the work of Halász and Székely, who in 1976 proved a law of large numbers for symmetric means. We study analytic properties of this Halász–Székely barycenter. We establish fundamental inequalities that relate the symmetric mean of a list of nonnegative real numbers with the barycenter of the measure uniformly supported on these points. As consequence, we go on to establish an ergodic theorem stating that the symmetric means of a se- quence of dynamical observations converges to the Halász–Székely barycenter of the corresponding distribution. 1. Introduction Means have fascinated man for a long time. Ancient Greeks knew the arith- metic, geometric, and harmonic means of two positive numbers (which they may have learned from the Babylonians); they also studied other types of means that can be defined using proportions: see [He, pp. 85–89]. Newton and Maclaurin en- countered the symmetric means (more about them later). Huygens introduced the notion of expected value and Jacob Bernoulli proved the first rigorous version of the law of large numbers: see [Mai, pp. 51, 73]. Gauss and Lagrange exploited the connection between the arithmetico-geometric mean and elliptic functions: see [BB]. Kolmogorov and other authors considered means from an axiomatic point of view and determined when a mean is arithmetic under a change of coordinates (i.e. quasiarithmetic): see [HLP, p.
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												  TOPIC 0 IntroductionTOPIC 0 Introduction 1 Review Course: Math 535 (http://www.math.wisc.edu/~roch/mmids/) - Mathematical Methods in Data Science (MMiDS) Author: Sebastien Roch (http://www.math.wisc.edu/~roch/), Department of Mathematics, University of Wisconsin-Madison Updated: Sep 21, 2020 Copyright: © 2020 Sebastien Roch We first review a few basic concepts. 1.1 Vectors and norms For a vector ⎡ 푥 ⎤ ⎢ 1 ⎥ 푥 ⎢ 2 ⎥ 푑 퐱 = ⎢ ⎥ ∈ ℝ ⎢ ⋮ ⎥ ⎣ 푥푑 ⎦ the Euclidean norm of 퐱 is defined as ‾‾푑‾‾‾‾ ‖퐱‖ = 푥2 = √퐱‾‾푇‾퐱‾ = ‾⟨퐱‾‾, ‾퐱‾⟩ 2 ∑ 푖 √ ⎷푖=1 푇 where 퐱 denotes the transpose of 퐱 (seen as a single-column matrix) and 푑 ⟨퐮, 퐯⟩ = 푢 푣 ∑ 푖 푖 푖=1 is the inner product (https://en.wikipedia.org/wiki/Inner_product_space) of 퐮 and 퐯. This is also known as the 2- norm. More generally, for 푝 ≥ 1, the 푝-norm (https://en.wikipedia.org/wiki/Lp_space#The_p- norm_in_countably_infinite_dimensions_and_ℓ_p_spaces) of 퐱 is given by 푑 1/푝 ‖퐱‖ = |푥 |푝 . 푝 (∑ 푖 ) 푖=1 Here (https://commons.wikimedia.org/wiki/File:Lp_space_animation.gif#/media/File:Lp_space_animation.gif) is a nice visualization of the unit ball, that is, the set {퐱 : ‖푥‖푝 ≤ 1}, under varying 푝. There exist many more norms. Formally: 푑 푑 Definition (Norm): A norm is a function ℓ from ℝ to ℝ+ that satisfies for all 푎 ∈ ℝ, 퐮, 퐯 ∈ ℝ (Homogeneity): ℓ(푎퐮) = |푎|ℓ(퐮) (Triangle inequality): ℓ(퐮 + 퐯) ≤ ℓ(퐮) + ℓ(퐯) (Point-separating): ℓ(푢) = 0 implies 퐮 = 0. ⊲ The triangle inequality for the 2-norm follows (https://en.wikipedia.org/wiki/Cauchy– Schwarz_inequality#Analysis) from the Cauchy–Schwarz inequality (https://en.wikipedia.org/wiki/Cauchy– Schwarz_inequality).
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												  Notes on the Calculus of ThermodynamicsSupplementary Notes for Chapter 5 The Calculus of Thermodynamics Objectives of Chapter 5 1. to understand the framework of the Fundamental Equation – including the geometric and mathematical relationships among derived properties (U, S, H, A, and G) 2. to describe methods of derivative manipulation that are useful for computing changes in derived property values using measurable, experimentally accessible properties like T, P, V, Ni, xi, and ρ . 3. to introduce the use of Legendre Transformations as a way of alternating the Fundamental Equation without losing information content Starting with the combined 1st and 2nd Laws and Euler’s theorem we can generate the Fundamental Equation: Recall for the combined 1st and 2nd Laws: • Reversible, quasi-static • Only PdV work • Simple, open system (no KE, PE effects) • For an n component system n dU = Td S − PdV + ∑()H − TS i dNi i=1 n dU = Td S − PdV + ∑µidNi i=1 and Euler’s Theorem: • Applies to all smoothly-varying homogeneous functions f, f(a,b,…, x,y, … ) where a,b, … intensive variables are homogenous to zero order in mass and x,y, extensive variables are homogeneous to the 1st degree in mass or moles (N). • df is an exact differential (not path dependent) and can be integrated directly if Y = ky and X = kx then Modified: 11/19/03 1 f(a,b, …, X,Y, …) = k f(a,b, …, x,y, …) and ⎛ ∂f ⎞ ⎛ ∂f ⎞ x⎜ ⎟ + y⎜ ⎟ + ... = ()1 f (a,b,...x, y,...) ⎝ ∂x ⎠a,b,...,y,.. ⎝ ∂y ⎠a,b,..,x,.. Fundamental Equation: • Can be obtained via Euler integration of combined 1st and 2nd Laws • Expressed in Energy (U) or Entropy (S) representation n U = fu []S,V , N1, N2 ,..., Nn = T S − PV + ∑µi Ni i=1 or n U P µi S = f s []U,V , N1, N2 ,..., Nn = + V − ∑ Ni T T i=1 T The following section summarizes a number of useful techniques for manipulating thermodynamic derivative relationships Consider a general function of n + 2 variables F ( x, y,z32,...,zn+ ) where x ≡ z1, y ≡ z2.
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												  Continuous Probability Distributions Continuous Probability Distributions – a Guide for Teachers (Years 11–12)1 Supporting Australian Mathematics Project 2 3 4 5 6 12 11 7 10 8 9 A guide for teachers – Years 11 and 12 Probability and statistics: Module 21 Continuous probability distributions Continuous probability distributions – A guide for teachers (Years 11–12) Professor Ian Gordon, University of Melbourne Editor: Dr Jane Pitkethly, La Trobe University Illustrations and web design: Catherine Tan, Michael Shaw Full bibliographic details are available from Education Services Australia. Published by Education Services Australia PO Box 177 Carlton South Vic 3053 Australia Tel: (03) 9207 9600 Fax: (03) 9910 9800 Email: [email protected] Website: www.esa.edu.au © 2013 Education Services Australia Ltd, except where indicated otherwise. You may copy, distribute and adapt this material free of charge for non-commercial educational purposes, provided you retain all copyright notices and acknowledgements. This publication is funded by the Australian Government Department of Education, Employment and Workplace Relations. Supporting Australian Mathematics Project Australian Mathematical Sciences Institute Building 161 The University of Melbourne VIC 3010 Email: [email protected] Website: www.amsi.org.au Assumed knowledge ..................................... 4 Motivation ........................................... 4 Content ............................................. 5 Continuous random variables: basic ideas ....................... 5 Cumulative distribution functions ............................ 6 Probability density functions ..............................
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												  Physical Chemistry II “The Mistress of the World and Her Shadow” Chemistry 402Physical Chemistry II “The mistress of the world and her shadow” Chemistry 402 L. G. Sobotka Department of Chemistry Washington University, St Louis, MO, 63130 January 3, 2012 Contents IIntroduction 7 1 Physical Chemistry II - 402 -Thermodynamics (mostly) 8 1.1Who,when,where.............................................. 8 1.2CourseContent/Logistics.......................................... 8 1.3Grading.................................................... 8 1.3.1 Exams................................................. 8 1.3.2 Quizzes................................................ 8 1.3.3 ProblemSets............................................. 8 1.3.4 Grading................................................ 8 2Constants 9 3 The Structure of Physical Science 10 3.1ClassicalMechanics.............................................. 10 3.2QuantumMechanics............................................. 11 3.3StatisticalMechanics............................................. 11 3.4Thermodynamics............................................... 12 3.5Kinetics.................................................... 13 4RequisiteMath 15 4.1 Exact differentials.............................................. 15 4.2Euler’sReciprocityrelation......................................... 15 4.2.1 Example................................................ 16 4.3Euler’sCyclicrelation............................................ 16 4.3.1 Example................................................ 16 4.4Integratingfactors.............................................. 17 4.5LegendreTransformations.........................................
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												  Exact and Inexact Differentials in the Early Development of MechanicsRevista Brasileira de Ensino de Física, vol. 42, e20190192 (2020) Articles www.scielo.br/rbef cb DOI: http://dx.doi.org/10.1590/1806-9126-RBEF-2019-0192 Licença Creative Commons Exact and inexact differentials in the early development of mechanics and thermodynamics Mário J. de Oliveira*1 1Universidade de São Paulo, Instituto de Física, São Paulo, SP, Brasil Received on July 31, 2019. Revised on October 8, 2019. Accepted on October 13, 2019. We give an account and a critical analysis of the use of exact and inexact differentials in the early development of mechanics and thermodynamics, and the emergence of differential calculus and how it was applied to solve some mechanical problems, such as those related to the cycloidal pendulum. The Lagrange equations of motions are presented in the form they were originally obtained in terms of differentials from the principle of virtual work. The derivation of the conservation of energy in differential form as obtained originally by Clausius from the equivalence of heat and work is also examined. Keywords: differential, differential calculus, analytical mechanics, thermodynamics. 1. Introduction variable x. If another variable y depends on the indepen- dent variable x, then the resulting increment dy of y is It is usual to formulate the basic equations of thermo- its differential. The quotient of these two differentials, dynamics in terms of differentials. The conservation of dy/dx, was interpreted geometrically by Leibniz as the energy is written as ratio of the ordinate y of a point on a curve and the length of the subtangent associated to this point.