Lecture

Transport Phenomena: Onsager Relations and Heat Equation

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In course

PHYS-105: Advanced physics II (thermodynamics)

Ce cours présente la thermodynamique en tant que théorie permettant une description d'un grand nombre de phénomènes importants en physique, chimie et ingéniere, et d'effets de transport. Une introduction à la physique statistique renforce les notions acqu ...

Description

This lecture introduces the concepts related to transport phenomena, focusing on Onsager relations, diffusion equation, Fourier's law, electrical transport, Ohm's law, Hall effect, thermoelectric effects, Fick's law, and thermophoresis. The slides cover topics such as electron conduction in metals, isotropic substances, density of electric charge, and magnetic induction fields.

Instructors (2)

Jean-Philippe Ansermet

Jean-Philippe Ansermet was born March 1, 1957 in Lausanne (legal origin Vaumarcus, NE). He obtained a diploma as physics engineer of EPFL in 1980. He went on to get a PhD from the University of Illinois at Urbana-Champaign where, from 1985 to 1987, he persued as post-doc with Prof. Slichter his research on catalysis by solid state NMR studies of molecules bound to the surface of catalysts. From 1987 to 1992 he worked at the materials research center of Ciba-Geigy, on polymers for microelectronics, composites, dielectrics and organic charge transfer complexes. In March 1992, as professor of experimental physics, he developed a laboratory on the theme of nanostructured materials and turned full professor in 1995. Since 1992, he teaches classical mechanics, first to future engineering students, since 2004 to physics majors. Since 2000, he teaches thermodynamics also, to the same group of students. He offers a graduate course in spintronics, and another on spin dynamics. His research activities concern the fabrication and properties of magnetic nanostructures produced by electrodeposition. His involvement since the early days of spintronics have allowed him to gain recognition for his work on giant magnetoresistance (CPP-GMR), magnetic relaxation of single nanostructures, and was among the leading groups demonstrating magnetization reversal by spin-polarized currents. Furthermore, his group uses nuclear magnetic resonance , on the one hand as means of investigation of surfaces and electrodes, on the other hand, as a local probe of the electronic properties of complex ferromagnetic oxides.

Cécile Hébert

Cécile Hébert was born in France in 1970. She obtained her Ingeneer degree (physics) and her PhD degree (design of a new energy filter for transmission electron microscopy, under the direction of Prof. B. Jouffrey) at the Ecole Centrale in Paris. As a post doc with Prof. P. Schattschneider, she was working on the calculation of the fine structure of ionisation edges in EELS. As a research assistant at the Vienna University of Technology, she was one of the main participant to the CHIRALTEM project dealing with the measurement of magnetic circular dichroism in the electron microscope.

Official source

Related concepts (32)

Thermal conduction

Conduction is the process by which heat is transferred from the hotter end to the colder end of an object. The ability of the object to conduct heat is known as its thermal conductivity, and is denoted k. Heat spontaneously flows along a temperature gradient (i.e. from a hotter body to a colder body). For example, heat is conducted from the hotplate of an electric stove to the bottom of a saucepan in contact with it.

Ohm's law

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, one arrives at the three mathematical equations used to describe this relationship: where I is the current through the conductor, V is the voltage measured across the conductor and R is the resistance of the conductor. More specifically, Ohm's law states that the R in this relation is constant, independent of the current.

Magnetic moment

In electromagnetism, the magnetic moment is the magnetic strength and orientation of a magnet or other object that produces a magnetic field. Examples of objects that have magnetic moments include loops of electric current (such as electromagnets), permanent magnets, elementary particles (such as electrons), composite particles (such as protons and neutrons), various molecules, and many astronomical objects (such as many planets, some moons, stars, etc).

Darcy's law

Darcy's law is an equation that describes the flow of a fluid through a porous medium. The law was formulated by Henry Darcy based on results of experiments on the flow of water through beds of sand, forming the basis of hydrogeology, a branch of earth sciences. It is analogous to Ohm's law in electrostatics, linearly relating the volume flow rate of the fluid to the hydraulic head difference (which is often just proportional to the pressure difference) via the hydraulic conductivity.

Magnetism

Magnetism is the class of physical attributes that occur through a magnetic field, which allows objects to attract or repel each other. Because both electric currents and magnetic moments of elementary particles give rise to a magnetic field, magnetism is one of two aspects of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves.

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