Science.gov

Sample records for maxwell statistics

  1. Maxwell's Daemon: Information versus Particle Statistics

    PubMed Central

    Plesch, Martin; Dahlsten, Oscar; Goold, John; Vedral, Vlatko

    2014-01-01

    Maxwell's daemon is a popular personification of a principle connecting information gain and extractable work in thermodynamics. A Szilard Engine is a particular hypothetical realization of Maxwell's daemon, which is able to extract work from a single thermal reservoir by measuring the position of particle(s) within the system. Here we investigate the role of particle statistics in the whole process; namely, how the extractable work changes if instead of classical particles fermions or bosons are used as the working medium. We give a unifying argument for the optimal work in the different cases: the extractable work is determined solely by the information gain of the initial measurement, as measured by the mutual information, regardless of the number and type of particles which constitute the working substance. PMID:25385291

  2. Maxwell's color statistics: from reduction of visible errors to reduction to invisible molecules.

    PubMed

    Cat, Jordi

    2014-12-01

    This paper presents a cross-disciplinary and multi-disciplinary account of Maxwell's introduction of statistical models of molecules for the composition of gases. The account focuses on Maxwell's deployment of statistical models of data in his contemporaneous color researches as established in Cambridge mathematical physics, especially by Maxwell's seniors and mentors. The paper also argues that the cross-disciplinary, or cross-domain, transfer of resources from the natural and social sciences took place in both directions and relied on the complex intra-disciplinary, or intra-domain, dynamics of Maxwell's researches in natural sciences, in color theory, physical astronomy, electromagnetism and dynamical theory of gases, as well as involving a variety of types of communicating and mediating media, from material objects to concepts, techniques and institutions.

  3. Cost of s-fold decisions in exact Maxwell Boltzmann, Bose Einstein and Fermi Dirac statistics

    NASA Astrophysics Data System (ADS)

    Niven, Robert K.

    2006-06-01

    The exact forms of the degenerate Maxwell-Boltzmann (MB), Bose-Einstein (BE) and Fermi-Dirac (FD) entropy functions, derived by Boltzmann's principle without the Stirling approximation [R.K. Niven, Physics Letters A, 342(4) (2005) 286], are further examined. Firstly, an apparent paradox in quantization effects is resolved using the Laplace-Jaynes interpretation of probability. The energy cost of learning that a system, distributed over s equiprobable states, is in one such state (an “ s-fold decision”) is then calculated for each statistic. The analysis confirms that the cost depends on one's knowledge of the number of entities N and (for BE and FD statistics) the degeneracy, extending the findings of Niven (2005).

  4. Maxwell electromagnetic theory, Planck's radiation law, and Bose—Einstein statistics

    NASA Astrophysics Data System (ADS)

    França, H. M.; Maia, A.; Malta, C. P.

    1996-08-01

    We give an example in which it is possible to understand quantum statistics using classical concepts. This is done by studying the interaction of chargedmatter oscillators with the thermal and zeropoint electromagnetic fields characteristic of quantum electrodynamics and classical stochastic electrodynamics. Planck's formula for the spectral distribution and the elements of energy hw are interpreted without resorting to discontinuities. We also show the aspects in which our model calculation complement other derivations of blackbody radiation spectrum without quantum assumptions.

  5. Maxwell's fishpond

    NASA Astrophysics Data System (ADS)

    Kinsler, Paul; Tan, Jiajun; Thio, Timothy C. Y.; Trant, Claire; Kandapper, Navin

    2012-11-01

    Most of us will have at some time thrown a pebble into water, and watched the ripples spread outwards and fade away. But now there is also a way to reverse the process, and make those ripples turn around and reconverge again, …and again, and again. To do this we have designed the Maxwell's fishpond, a water wave or ‘transformation aquatics’ version of the Maxwell's fisheye lens (Tyc et al 2011 New J. Phys. 13 115004; Luneburg 1964 Mathematical Theory of Optics). These are transformation devices where wave propagation on the surface of a sphere is modelled using a flat device with spatially varying properties. And just as for rays from a point source on a sphere, a wave disturbance in a Maxwell's fisheye or fishpond spreads out at first, but then reforms itself at its opposite (or complementary) point. Here we show how such a device can be made for water waves, partly in friendly competition with comparable electromagnetic devices (Ma et al 2011 New J. Phys. 13 033016) and partly as an accessible and fun demonstration of the power of transformation mechanics. To the eye, our Maxwell's fishpond was capable of reforming a disturbance up to five times, although such a feat required taking considerable care, close observation, and a little luck.

  6. RANDOMNESS of Numbers DEFINITION(QUERY:WHAT? V HOW?) ONLY Via MAXWELL-BOLTZMANN CLASSICAL-Statistics(MBCS) Hot-Plasma VS. Digits-Clumping Log-Law NON-Randomness Inversion ONLY BOSE-EINSTEIN QUANTUM-Statistics(BEQS) .

    NASA Astrophysics Data System (ADS)

    Siegel, Z.; Siegel, Edward Carl-Ludwig

    2011-03-01

    RANDOMNESS of Numbers cognitive-semantics DEFINITION VIA Cognition QUERY: WHAT???, NOT HOW?) VS. computer-``science" mindLESS number-crunching (Harrel-Sipser-...) algorithmics Goldreich "PSEUDO-randomness"[Not.AMS(02)] mea-culpa is ONLY via MAXWELL-BOLTZMANN CLASSICAL-STATISTICS(NOT FDQS!!!) "hot-plasma" REPULSION VERSUS Newcomb(1881)-Weyl(1914;1916)-Benford(1938) "NeWBe" logarithmic-law digit-CLUMPING/ CLUSTERING NON-Randomness simple Siegel[AMS Joint.Mtg.(02)-Abs. # 973-60-124] algebraic-inversion to THE QUANTUM and ONLY BEQS preferentially SEQUENTIALLY lower-DIGITS CLUMPING/CLUSTERING with d = 0 BEC, is ONLY VIA Siegel-Baez FUZZYICS=CATEGORYICS (SON OF TRIZ)/"Category-Semantics"(C-S), latter intersection/union of Lawvere(1964)-Siegel(1964)] category-theory (matrix: MORPHISMS V FUNCTORS) "+" cognitive-semantics'' (matrix: ANTONYMS V SYNONYMS) yields Siegel-Baez FUZZYICS=CATEGORYICS/C-S tabular list-format matrix truth-table analytics: MBCS RANDOMNESS TRUTH/EMET!!!

  7. Maxwell's silver theramin

    NASA Astrophysics Data System (ADS)

    O'Brien, Sheila

    2012-12-01

    I found Nicole Yunger-Halpern's Lateral Thoughts on "Fiddling around with physics" (September p60) quite amusing, but I am sure James Clerk Maxwell would have preferred to play the theramin instead of the electric guitar.

  8. Unmasking Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Nieuwenhuizen, Theo M.; Allahverdyan, Armen E.

    2002-11-01

    Maxwell's demon is a tiny but fine-fingered being, capable to extract work from a system at instantaneous equilibrium, without needing energy input or information erasure. In the 20'th century many workers have claimed that the demon cannot operate. Here the point of view is taken that this exorcism of the demon never applied, since one did not consider Maxwell's original invention. For a Brownian particle coupled to a quantum bath it was shown by us that quantum entanglement can allow extraction of work from a non-equilibrium system coupled to a single bath. And mesoscopic work sources may establish work extraction cycles even when they are coupled to equilibrium mesoscopic systems immersed in a macroscopic thermal bath. Quantum entanglement and mesocopicity are now identified with (true) Maxwell demons.

  9. Obtaining Maxwell's equations heuristically

    NASA Astrophysics Data System (ADS)

    Diener, Gerhard; Weissbarth, Jürgen; Grossmann, Frank; Schmidt, Rüdiger

    2013-02-01

    Starting from the experimental fact that a moving charge experiences the Lorentz force and applying the fundamental principles of simplicity (first order derivatives only) and linearity (superposition principle), we show that the structure of the microscopic Maxwell equations for the electromagnetic fields can be deduced heuristically by using the transformation properties of the fields under space inversion and time reversal. Using the experimental facts of charge conservation and that electromagnetic waves propagate with the speed of light, together with Galilean invariance of the Lorentz force, allows us to finalize Maxwell's equations and to introduce arbitrary electrodynamics units naturally.

  10. Maxwell's Demon and the Second Law

    NASA Astrophysics Data System (ADS)

    Leff, Harvey S.; Rex, Andrew F.

    2002-11-01

    Maxwell's demon emanates from a thought experiment proposed by James Clerk Maxwell in 1867 to illustrate the statistical nature of the second law of thermodynamics. Subsequently researchers wondered whether such a demon could in fact violate the second law. Leon Brillouin argued that the entropy produced during the demon's measurement precluded such a violation. Years later Oliver Penrose and Charles Bennett observed (independently) that a Maxwell's demon gathers information and stores it in a memory. Penrose showed that erasure of such a memory sends sufficient entropy to the environment to preclude violation of the second law. Notably this is so even when measurement produces arbitrarily little entropy. Bennett obtained the same result using Rolf Landauer's seminal research on the thermodynamics of computation. The stunning shift in focus from measurement to erasure provided the impetus to better understand the role of information in quantum mechanics and thermodynamics. Indeed the linkage of information with physics is the principal legacy of Maxwell's demon. Szilard's one-particle classical "gas" model and its quantum mechanical extension, together with postulated connections between entropy and algorithmic information, have provided useful insights. We review the long history of Maxwell's demon and assess the current status of the second law in the context of the demon's operations.

  11. Uniqueness of Maxwell's Equations.

    ERIC Educational Resources Information Center

    Cohn, Jack

    1978-01-01

    Shows that, as a consequence of two feasible assumptions and when due attention is given to the definition of charge and the fields E and B, the lowest-order equations that these two fields must satisfy are Maxwell's equations. (Author/GA)

  12. An Omniscient Maxwell Demon

    NASA Astrophysics Data System (ADS)

    Weiss, David S.; Vala, Jiri; Thapliyal, Ashish V.; Myrgren, Simon; Vazirani, Umesh; Whaley, K. Birgitta

    2003-05-01

    We present a proposed experimental scheme for collecting detailed information about a disordered system, and then acting on that system in a reversible way to obtain a state of manifestly zero entropy. Specifically, the locations of vacancies of laser cooled atoms in an optical lattice can be measured. The distribution can then be efficiently compacted using a combination of site specific state flips and state-sensitive lattice site translations. The computer, armed with complete information about the system, acts in the same sense as the active demon that Maxwell envisaged.

  13. James Clerk Maxwell and religion

    NASA Astrophysics Data System (ADS)

    Theerman, Paul

    1986-04-01

    The evolution of James Clerk Maxwell's religious beliefs is described. His college-age conversion experience and his membership in the ``Apostles'' were crucial in his religious development. In his mature statements, Maxwell denied that scientific truth was dependent on religious truth, or the reverse. Nonetheless, scientific conclusions could enrich religious contemplation of God's actions in nature. Maxwell provided a religious interpretation of the apparent uniformity and eternity of atoms.

  14. Engineering Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Lu, Zhiyue; Mandal, Dibyendu; Jarzynski, Christopher

    2015-03-01

    We describe a hypothetical machine, with moving, mechanical components, that acts as an autonomous Maxwell's demon. The machine operates in two useful modes. It can act as an information engine by rectifying the thermal motions of surrounding gas particles to lift a mass against gravity, while writing information to a stream of bits. Alternatively, it can act as an eraser, harnessing the energy of a falling mass to erase information from a stream of bits. We solve for the phase diagram and compute the efficiency of our model, both analytically and numerically. Our model provides a simple example of a mechanical machine that is driven by the information entropy of a stream of bits, rather than a difference in temperatures or chemical potentials. This research is supported by the U.S. Army Research Office under Contract Number W911NF-13-1-0390.

  15. Reduced Vlasov-Maxwell simulations

    NASA Astrophysics Data System (ADS)

    Helluy, Philippe; Navoret, Laurent; Pham, Nhung; Crestetto, Anaïs

    2014-10-01

    In this paper we review two different numerical methods for Vlasov-Maxwell simulations. The first method is based on a coupling between a Discontinuous Galerkin (DG) Maxwell solver and a Particle-In-Cell (PIC) Vlasov solver. The second method only uses a DG approach for the Vlasov and Maxwell equations. The Vlasov equation is first reduced to a space-only hyperbolic system thanks to the finite-element method. The two numerical methods are implemented using OpenCL in order to achieve high performance on recent Graphic Processing Units (GPU).

  16. Maxwell's Enduring Legacy

    NASA Astrophysics Data System (ADS)

    Longair, Malcolm

    2016-07-01

    Preface; Acknowledgements; Figure credits; Part I. To 1874: 1. Physics in the nineteenth century; 2. Mathematics and physics in Cambridge in the nineteenth century; Part II. 1874 to 1879: 3. The Maxwell era; Part III. 1879 to 1884: 4. Rayleigh's Quinquennium; Part IV. 1884 to 1919: 5. The challenges facing J. J. Thomson; 6. The J. J. Thomson era, 1884-1900 - the electron; 7. The Thomson era, 1900-19 - atomic structure; Part V. 1919 to 1937: 8. Rutherford at McGill and Manchester Universities - new challenges in Cambridge; 9. The Rutherford era - the radioactivists; 10. Rutherford era - the seeds of the new physics; Part VI. 1938 to 1953: 11. Bragg and the war years; 12. Bragg and the post-war years; Part VII. 1953 to 1971: 13. The Mott era - an epoch of expansion; 14. The Mott era - radio astronomy and high energy physics; 15. The Mott era - the growth of condensed matter physics; Part VIII. 1971 to 1982: 16. The Pippard era - a new laboratory and a new vision; 17. The Pippard era - radio astronomy, high energy physics and laboratory astrophysics; 18. The Pippard era - condensed matter physics; Part IX. 1984 to 1995: 19. The Edwards era - a new epoch of expansion; 20. The Edwards era - new directions in condensed matter physics; 21. The Edwards era - high energy physics and radio astronomy; Part X. 1995 to present: 22. Towards the new millennium and beyond; 23. The evolution of the New Museums site; Notes; Bibliography; Author index; Index.

  17. The Road to Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Hemmo, Meir; Shenker, Orly R.

    2014-07-01

    Preface; 1. Introduction; 2. Thermodynamics; 3. Classical mechanics; 4. Time; 5. Macrostates; 6. Probability; 7. Entropy; 8. Typicality; 9. Measurement; 10. The past; 11. Gibbs; 12. Erasure; 13. Maxwell's Demon; Appendixes; References; Index.

  18. The Road to Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Hemmo, Meir; Shenker, Orly R.

    2012-09-01

    Preface; 1. Introduction; 2. Thermodynamics; 3. Classical mechanics; 4. Time; 5. Macrostates; 6. Probability; 7. Entropy; 8. Typicality; 9. Measurement; 10. The past; 11. Gibbs; 12. Erasure; 13. Maxwell's Demon; Appendixes; References; Index.

  19. James Clerk Maxwell and the Kinetic Theory of Gases: A Review Based on Recent Historical Studies

    ERIC Educational Resources Information Center

    Brush, Stephen G.

    1971-01-01

    Maxwell's four major papers and some shorter publications relating to kinetic theory and statistical mechanics are discussed in the light of subsequent research. Reviews Maxwell's ideas on such topics as velocity, distribution law, the theory of heat conduction, the mechanism of the radiometer effect, the ergodic hypothesis, and his views on the…

  20. Maxwell's demon and data compression

    NASA Astrophysics Data System (ADS)

    Hosoya, Akio; Maruyama, Koji; Shikano, Yutaka

    2011-12-01

    In an asymmetric Szilard engine model of Maxwell's demon, we show the equivalence between information theoretical and thermodynamic entropies when the demon erases information optimally. The work gain by the engine can be exactly canceled out by the work necessary to reset the demon's memory after optimal data compression in the manner of Shannon before the erasure.

  1. The discovery of Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Everitt, Francis

    2012-02-01

    In January 1865, Maxwell at age 34 wrote a letter to his cousin Charles Cay describing various doings, including his work on the viscosity of gases and a visit from two of the world's leading oculists to inspect the eyes of his dog ``Spice''. He added, ``I have also a paper afloat, with an electromagnetic theory of light, which, till I am convinced to the contrary, I hold to be great guns.'' That paper ``A Dynamical Theory of the Electromagnetic Field'' was his fourth on the subject. It was followed in 1868 by another, and then in 1873 by his massive two volume Treatise on Electricity and Magnetism. Even so, by the time of his death in 1879 as he was beginning a radically revised edition of the Treatise, much remained to be done. We celebrate here the 150^th anniversary of Maxwell's first astonished realization in 1862 of the link between electromagnetism and light. So revolutionary was this that 15 or more years went by before Lorentz, Poynting, FitzGerald, and others came to address it, sometimes with improvements, sometimes not. Not until 1888 did Hertz make the essential experimental discovery of radio waves. What is so remarkable about Maxwell's five papers is that each presents a complete view of the subject radically different from the one before. I shall say something about each, emphasizing in particular Maxwell's most unexpected idea, the displacement current, so vastly more interesting than the accounts of it found in textbooks today. Beyond lie other surprises. The concept of gauge invariance, and the role the vector potential would play in defining the canonical momentum of the electron, both go back to Maxwell. In 1872 came a paper ``On the Mathematical Classification of Physical Quantities'', which stands as an education in itself. Amid much else, there for the first time appears the distinction between axial and polar vectors and those new operational concepts related to quaternion theory: curl, divergence, and gradient.

  2. Are Maxwell's equations Lorentz-covariant?

    NASA Astrophysics Data System (ADS)

    Redžić, D. V.

    2017-01-01

    It is stated in many textbooks that Maxwell's equations are manifestly covariant when written down in tensorial form. We recall that tensorial form of Maxwell's equations does not secure their tensorial contents; they become covariant by postulating certain transformation properties of field functions. That fact should be stressed when teaching about the covariance of Maxwell's equations.

  3. Environmental Assessment: Disposition of Maxwell Heights Annex

    DTIC Science & Technology

    2005-07-01

    Maxwell Support Division May 4, 2005 Mr. David Rabon Tribal Historic Preservation Officer Cherokee Nation of Oklahoma P.O. Box 948 Tahlequah...Oklahoma 74465 RE: Disposal of the Existing Property and Facilities of the Maxwell Heights Annex Maxwell Air Force Base, Alabama Dear Mr. Rabon , The

  4. Statistics

    Cancer.gov

    Links to sources of cancer-related statistics, including the Surveillance, Epidemiology and End Results (SEER) Program, SEER-Medicare datasets, cancer survivor prevalence data, and the Cancer Trends Progress Report.

  5. James Clerk Maxwell: Life and science

    NASA Astrophysics Data System (ADS)

    Marston, Philip L.

    2016-07-01

    Maxwell's life and science are presented with an account of the progression of Maxwell's research on electromagnetic theory. This is appropriate for the International Year of Light and Light-based Technologies, 2015. Maxwell's own confidence in his 1865 electromagnetic theory of light is examined, along with some of the difficulties he faced and the difficulties faced by some of his followers. Maxwell's interest in radiation pressure and electromagnetic stress is addressed, as well as subsequent developments. Some of Maxwell's other contributions to physics are discussed with an emphasis on the kinetic and molecular theory of gases. Maxwell's theistic perspective on science is illustrated, accompanied by examples of perspectives on Maxwell and his science provided by his peers and accounts of his interactions with those peers. Appendices examine the peer review of Maxwell's 1865 electromagnetic theory paper and the naming of the Maxwell Garnett effective media approximation and provide various supplemental perspectives. From Maxwell's publications and correspondence there is evidence he had a high regard for Michael Faraday. Examples of Maxwell's contributions to electromagnetic terminology are noted.

  6. Structural mapping of Maxwell Montes

    NASA Technical Reports Server (NTRS)

    Keep, Myra; Hansen, Vicki L.

    1993-01-01

    Four sets of structures were mapped in the western and southern portions of Maxwell Montes. An early north-trending set of penetrative lineaments is cut by dominant, spaced ridges and paired valleys that trend northwest. To the south the ridges and valleys splay and graben form in the valleys. The spaced ridges and graben are cut by northeast-trending graben. The northwest-trending graben formed synchronously with or slightly later than the spaced ridges. Formation of the northeast-trending graben may have overlapped with that of the northwest-trending graben, but occurred in a spatially distinct area (regions of 2 deg slope). Graben formation, with northwest-southeast extension, may be related to gravity-sliding. Individually and collectively these structures are too small to support the immense topography of Maxwell, and are interpreted as parasitic features above a larger mass that supports the mountain belt.

  7. Joseph Maxwell on mediumistic personifications.

    PubMed

    Alvarado, Carlos S

    2016-09-01

    The study of mediumship received much impetus from the work of psychical researchers. This included ideas about the phenomena of personation, or changes in attitudes, dispositions and behaviours shown by some mediums that supposedly indicated discarnate action. The aim of this Classic Text is to reprint passages about this topic from the writings of French psychical researcher Joseph Maxwell (1858-1938), which were part of the contributions of some psychical researchers to reconceptualize the manifestations in psychological terms. Maxwell suggested these changes in mediums were a production of their subconscious mind. His ideas are a reflection of previous theorization about secondary personalities and a particular example of the contributions of psychical researchers to understand the psychology of mediumship.

  8. The Statistical Basis of Chemical Equilibria.

    ERIC Educational Resources Information Center

    Hauptmann, Siegfried; Menger, Eva

    1978-01-01

    Describes a machine which demonstrates the statistical bases of chemical equilibrium, and in doing so conveys insight into the connections among statistical mechanics, quantum mechanics, Maxwell Boltzmann statistics, statistical thermodynamics, and transition state theory. (GA)

  9. Historic Landscape Survey, Maxwell AFB, Alabama

    DTIC Science & Technology

    2013-08-01

    lands in Alabama. Also at this time, investigators conducted a Cold War era architectural resources survey at Maxwell AFB and Gunter Annex. This...as suggestions for possible planting strategies for the component landscapes. 5.1 Overall management guidelines • The Maxwell AFB road network was...lists, consult with the Maxwell AFB Natural Resources Manager or horticulturalist. ERDC/CERL TR-13-12 217 Table 3. Trees approved for planting on

  10. Introducing polarization and magnetization into Maxwell's equations: A modified approach

    NASA Astrophysics Data System (ADS)

    Jakoby, Bernhard

    2014-01-01

    The introduction of electric polarization and magnetization—the density of electric and magnetic dipole moments respectively—into Maxwell's equations requires establishing their respective relation to polarization charges and magnetization currents. Using a method introduced by Feynman in his famous lectures on physics and considering statistically distributed dipoles on the microscopic scale, the desired relations can be established in a manner that may be more intuitive to undergraduate students.

  11. Geometric Implications of Maxwell's Equations

    NASA Astrophysics Data System (ADS)

    Smith, Felix T.

    2015-03-01

    Maxwell's synthesis of the varied results of the accumulated knowledge of electricity and magnetism, based largely on the searching insights of Faraday, still provide new issues to explore. A case in point is a well recognized anomaly in the Maxwell equations: The laws of electricity and magnetism require two 3-vector and two scalar equations, but only six dependent variables are available to be their solutions, the 3-vectors E and B. This leaves an apparent redundancy of two degrees of freedom (J. Rosen, AJP 48, 1071 (1980); Jiang, Wu, Povinelli, J. Comp. Phys. 125, 104 (1996)). The observed self-consistency of the eight equations suggests that they contain additional information. This can be sought as a previously unnoticed constraint connecting the space and time variables, r and t. This constraint can be identified. It distorts the otherwise Euclidean 3-space of r with the extremely slight, time dependent curvature k (t) =Rcurv-2 (t) of the 3-space of a hypersphere whose radius has the time dependence dRcurv / dt = +/- c nonrelativistically, or dRcurvLor / dt = +/- ic relativistically. The time dependence is exactly that of the Hubble expansion. Implications of this identification will be explored.

  12. From Maxwell's theory of Saturn's rings to the negative mass instability.

    PubMed

    Fedele, Renato

    2008-05-28

    The impact of Maxwell's theory of Saturn's rings, formulated in Aberdeen ca 1856, is discussed. One century later, Nielsen, Sessler and Symon formulated a similar theory to describe the coherent instabilities (in particular, the negative mass instability) exhibited by a charged particle beam in a high-energy accelerating machine. Extended to systems of particles where the mutual gravitational attraction is replaced by the electric repulsion, Maxwell's approach was the conceptual basis to formulate the kinetic theory of coherent instability (Vlasov-Maxwell system), which, in particular, predicts the stabilizing role of the Landau damping. However, Maxwell's idea was so fertile that, later on, it was extended to quantum-like models (e.g. thermal wave model), providing the quantum-like description of coherent instability (Schrödinger-Maxwell system) and its identification with the modulational instability (MI). The latter has recently been formulated for any nonlinear wave propagation governed by the nonlinear Schrödinger equation, as in the statistical approach to MI (Wigner-Maxwell system). It seems that the above recent developments may provide a possible feedback to Maxwell's original idea with the extension to quantum gravity and cosmology.

  13. Vortex shedding and Maxwell's problem

    NASA Astrophysics Data System (ADS)

    Michelin, Sebastien; Smith, Stefan Llewellyn

    2006-11-01

    The coupled problem of a flow around a solid body has applications from the fall of objects in a fluid to the computation of forces on wind-exposed structures. A simplified 2D model is proposed here for the interaction between solid bodies and potential flows. Potential flows over sharp edges generate singular velocities at the edges. To satisfy the Kutta condition, vorticity sheets must be shed from the edges to remove these singularities. Here 2D vorticity sheets are represented as discrete point-vortices with monotically varying intensity. From the fluid momentum conservation, an equation of motion for these vortices, the Brown and Michael equation, is derived and mechanical efforts applied by the fluid on the body are computed. The set of dynamical equations obtained for the fluid-body system is closed and is applied to Maxwell's problem of the 2D fall of a plate in an inviscid fluid initially at rest.

  14. Galerkin GX Vlasov-Maxwell system

    NASA Astrophysics Data System (ADS)

    Burby, Joshua

    2016-10-01

    A variety of ''gyroaveraged'' kinetic plasma models are structurally very similar, even though they describe different physical processes. I will show that drift kinetics, gyro kinetics, and Vlasov-Maxwell theory are all particular examples of a much more general theory that I call GX Vlasov-Maxwell theory. The GX Vlasov-Maxwell system is an infinite-dimensional Hamiltonian system. Starting from the GX Vlasov-Maxwell system, I will derive a finite-dimensional version of the theory called Galerikin GX Vlasov-Maxwell theory. By representing the electromagnetic field using finite element exterior calculus, and replacing the one-particle distribution function with the Klimontovich distribution, the partial differential-integral equation that comprises the GX Vlasov-Maxwell system will be replaced with a finite dimensional ordinary differential equation. The conserved Hamiltonian and Poisson bracket for this system will be presented. While infinite-dimensional Hamiltonian systems do not possess (functional) Liouville measures, finite dimensional approximations of these systems do. The expression for Galerkin GX Vlasov-Maxwell theory's Liouville volume will be presented.

  15. The Proell Effect: A Macroscopic Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Rauen, Kenneth M.

    2011-12-01

    Maxwell's Demon is a legitimate challenge to the Second Law of Thermodynamics when the "demon" is executed via the Proell effect. Thermal energy transfer according to the Kinetic Theory of Heat and Statistical Mechanics that takes place over distances greater than the mean free path of a gas circumvents the microscopic randomness that leads to macroscopic irreversibility. No information is required to sort the particles as no sorting occurs; the entire volume of gas undergoes the same transition. The Proell effect achieves quasi-spontaneous thermal separation without sorting by the perturbation of a heterogeneous constant volume system with displacement and regeneration. The classical analysis of the constant volume process, such as found in the Stirling Cycle, is incomplete and therefore incorrect. There are extra energy flows that classical thermo does not recognize. When a working fluid is displaced across a regenerator with a temperature gradient in a constant volume system, complimentary compression and expansion work takes place that transfers energy between the regenerator and the bulk gas volumes of the hot and cold sides of the constant volume system. Heat capacity at constant pressure applies instead of heat capacity at constant volume. The resultant increase in calculated, recyclable energy allows the Carnot Limit to be exceeded in certain cycles. Super-Carnot heat engines and heat pumps have been designed and a US patent has been awarded.

  16. Gauged Ads-Maxwell Algebra and Gravity

    NASA Astrophysics Data System (ADS)

    Durka, R.; Kowalski-Glikman, J.; Szczachor, M.

    We deform the anti-de Sitter algebra by adding additional generators {Z}ab, forming in this way the negative cosmological constant counterpart of the Maxwell algebra. We gauge this algebra and construct a dynamical model with the help of a constrained BF theory. It turns out that the resulting theory is described by the Einstein-Cartan action with Holst term, and the gauge fields associated with the Maxwell generators {Z}ab appear only in topological terms that do not influence dynamical field equations. We briefly comment on the extension of this construction, which would lead to a nontrivial Maxwell fields dynamics.

  17. Cautious revolutionaries: Maxwell, Planck, Hubble

    NASA Astrophysics Data System (ADS)

    Brush, Stephen G.

    2002-02-01

    Three scientists exemplified the cautious behavior that we might like all scientists to display: indeed, they were so critical of their own ideas that they risked losing credit for them. Nevertheless, they finally earned at least as much fame as they deserved, leaving historians to wonder about what they really believed. Maxwell initially rejected the kinetic theory of gases because two of its predictions disagreed with experiments; later he revived the theory, showed that one of those experiments had been misinterpreted, and eventually became known as one of the founders of the modern theory. Planck seems to have intended his 1900 quantum hypothesis as a mathematical device, not a physical discontinuity; later he limited it to the emission (not absorption) of radiation, thereby discovering ``zero-point energy.'' Eventually he accepted the physical quantum hypothesis and became known as its discoverer. Hubble (with Humason) established the distance-velocity law, which others used as a basis for the expanding universe theory; later he suggested that redshifts may not be due to motion and appeared to lean toward a static model in place of the expanding universe.

  18. Green`s function of Maxwell`s equations and corresponding implications for iterative methods

    SciTech Connect

    Singer, B.S.; Fainberg, E.B.

    1996-12-31

    Energy conservation law imposes constraints on the norm and direction of the Hilbert space vector representing a solution of Maxwell`s equations. In this paper, we derive these constrains and discuss the corresponding implications for the Green`s function of Maxwell`s equations in a dissipative medium. It is shown that Maxwell`s equations can be reduced to an integral equation with a contracting kernel. The equation can be solved using simple iterations. Software based on this algorithm have successfully been applied to a wide range of problems dealing with high contrast models. The matrix corresponding to the integral equation has a well defined spectrum. The equation can be symmetrized and solved using different approaches, for instance one of the conjugate gradient methods.

  19. Shock waves: The Maxwell-Cattaneo case.

    PubMed

    Uribe, F J

    2016-03-01

    Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈ M(1) < M < M(2) ≈ 1.90) such that numerical shock wave solutions to the Maxwell-Cattaneo equations cannot be found, and

  20. How Maxwell's equations came to light

    NASA Astrophysics Data System (ADS)

    Mahon, Basil

    2015-01-01

    The nineteenth-century Scottish physicist James Clerk Maxwell made groundbreaking contributions to many areas of science including thermodynamics and colour vision. However, he is best known for his equations that unified electricity, magnetism and light.

  1. Maxwell Duality, Lorentz Invariance, and Topological Phase

    NASA Technical Reports Server (NTRS)

    Dowling, J.; Williams, C.; Franson, J.

    1999-01-01

    We discuss the Maxwell electromagnetic duality relations between the Aharonov-Bohm, Aharonov-Casher, and He-McKellar-Wilkens topological phases, which allows a unified description of all three phenomena.

  2. Maxwellians and the Remaking of Maxwell's Equations

    NASA Astrophysics Data System (ADS)

    Hunt, Bruce

    2012-02-01

    Although James Clerk Maxwell first formulated his theory of the electromagnetic field in the early 1860s, it went through important changes before it gained general acceptance in the 1890s. Those changes were largely the work of a group of younger physicists, the Maxwellians, led by G. F. FitzGerald in Ireland, Oliver Lodge and Oliver Heaviside in England, and Heinrich Hertz in Germany. Together, they extended, refined, tested, and confirmed Maxwell's theory, and recast it into the set of four vector equations known ever since as ``Maxwell's equations.'' By tracing how the Maxwellians remade and disseminated Maxwell's theory between the late 1870s and the mid-1890s, we can gain a clearer understanding not just of how the electromagnetic field was understood at the end of the 19th century, but of the collaborative nature of work at the frontiers of physics.

  3. Magnetic monopoles, Galilean invariance, and Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Crawford, Frank S.

    1992-02-01

    Maxwell's equations have space reserved for magnetic monopoles. Whether or not they exist in our part of the universe, monopoles provide a useful didactic tool to help us recognize relations among Maxwell's equations less easily apparent in the approach followed by many introductory textbooks, wherein Coulomb's law, Biot and Savart's law, Ampere's law, Faraday's law, Maxwell's displacement current, etc., are introduced independently, ``as demanded by experiment.'' Instead a conceptual path that deduces all of Maxwell's equations from the near-minimal set of assumptions: (a) Inertial frames exist, in which Newton's laws hold, to a first approximation; (b) the laws of electrodynamics are Galilean invariant-i.e., they have the same form in every inertial frame, to a first approximation; (c) magnetic poles (as well as the usual electric charges) exist; (d) the complete Lorentz force on an electric charge is known; (e) the force on a monopole at rest is known; (f) the Coulomb-like field produced by a resting electric charge and by a resting monopole are known. Everything else is deduced. History is followed in the assumption that Newtonian mechanics have been discovered, but not special relativity. (Only particle velocities v<Maxwell's equations (Maxwell did not need special relativity, so why should we,) but facing Einstein's paradox, the solution of which is encapsulated in the Einstein velocity-addition formula.

  4. Maxwell times in higher-order generalized hydrodynamics: Classical fluids, and carriers and phonons in semiconductors.

    PubMed

    Rodrigues, Clóves G; Silva, Carlos A B; Ramos, José G; Luzzi, Roberto

    2017-02-01

    A family of what can be so-called Maxwell times which arises in the context of higher-order generalized hydrodynamics (HOGH; also called mesoscopic hydrothermodynamics) is evidenced. This is done in the framework of a HOGH built within a statistical formalism in terms of a nonequilibrium statistical ensemble formalism. It consists in a description in terms of the densities of particles and energy and their fluxes of all orders, with the motion described by a set of coupled nonlinear integro-differential equations involving them. These Maxwell times have a fundamental role in determining the type of hydrodynamic motion that the system would display in the given conditions and constraints. They determine a Maxwell viscous force not present in the usual hydrodynamic equations, for example, in Navier-Stokes equation.

  5. Maxwell times in higher-order generalized hydrodynamics: Classical fluids, and carriers and phonons in semiconductors

    NASA Astrophysics Data System (ADS)

    Rodrigues, Clóves G.; Silva, Carlos A. B.; Ramos, José G.; Luzzi, Roberto

    2017-02-01

    A family of what can be so-called Maxwell times which arises in the context of higher-order generalized hydrodynamics (HOGH; also called mesoscopic hydrothermodynamics) is evidenced. This is done in the framework of a HOGH built within a statistical formalism in terms of a nonequilibrium statistical ensemble formalism. It consists in a description in terms of the densities of particles and energy and their fluxes of all orders, with the motion described by a set of coupled nonlinear integro-differential equations involving them. These Maxwell times have a fundamental role in determining the type of hydrodynamic motion that the system would display in the given conditions and constraints. They determine a Maxwell viscous force not present in the usual hydrodynamic equations, for example, in Navier-Stokes equation.

  6. Venus - Maxwell Montes and Cleopatra Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This Magellan full-resolution image shows Maxwell Montes, and is centered at 65 degrees north latitude and 6 degrees east longitude. Maxwell is the highest mountain on Venus, rising almost 11 kilometers (6.8 miles) above mean planetary radius. The western slopes (on the left) are very steep, whereas the eastern slopes descend gradually into Fortuna Tessera. The broad ridges and valleys making up Maxwell and Fortuna suggest that the topography resulted from compression. Most of Maxwell Montes has a very bright radar return; such bright returns are common on Venus at high altitudes. This phenomenon is thought to result from the presence of a radar reflective mineral such as pyrite. Interestingly, the highest area on Maxwell is less bright than the surrounding slopes, suggesting that the phenomenon is limited to a particular elevation range. The pressure, temperature, and chemistry of the atmosphere vary with altitude; the material responsible for the bright return probably is only stable in a particular range of atmospheric conditions and therefore a particular elevation range. The prominent circular feature in eastern Maxwell is Cleopatra. Cleopatra is a double-ring impact basin about 100 kilometers (62 miles) in diameter and 2.5 kilometers (1.5 miles) deep. A steep-walled, winding channel a few kilometers wide breaks through the rough terrain surrounding the crater rim. A large amount of lava originating in Cleopatra flowed through this channel and filled valleys in Fortuna Tessera. Cleopatra is superimposed on the structures of Maxwell Montes and appears to be undeformed, indicating that Cleopatra is relatively young.

  7. Maxwell's demon. (I) A thermodynamic exorcism

    NASA Astrophysics Data System (ADS)

    Gyftopoulos, Elias P.

    2002-05-01

    It is shown that Maxwell's demon is unable to accomplish his task not because of considerations related to irreversibility, acquisition of information, and computers and erasure of information but because of limitations imposed by the properties of the system on which he is asked to perform his demonic manipulations. The limitations emerge from two recent but related developments of which Maxwell was completely unaware. One is an exposition of thermodynamics as a nonstatistical theory, valid for all systems, both large and small, including a system with only one degree of (translational) freedom, and for all states, both thermodynamic or stable equilibrium states and states that are not thermodynamic equilibrium, including states encountered in mechanics. In this theory, entropy is proven to be a nondestructible, nonstatistical property of any state in the same sense that inertial mass is a nonstatistical property of any state. In Part I, the demon is shown to be incapable of accomplishing his task because this would be equivalent either to reducing the nondestructible and nonstatistical entropy of air in a container without compensation by any other system, including himself, or to extracting only energy from the air under conditions that require the extraction of both energy and entropy. The second development is a unified, quantum-theoretic interpretation of mechanics and the thermodynamics just cited. In this theory: (a) the quantum-theoretic probabilities of measurement results are represented by a density operator ρ that corresponds to a homogeneous ensemble of identical systems, identically prepared; homogeneous is an ensemble in which every member is described by the same density operator ρ as any other member, that is, the ensemble is not a statistical mixture of projectors (wave functions); said differently, experimentally (as opposed to algebraically) the homogeneous ensemble cannot be decomposed into mixtures either of pure states or other mixtures

  8. Maxwell's demons realized in electronic circuits

    NASA Astrophysics Data System (ADS)

    Koski, Jonne V.; Pekola, Jukka P.

    2016-12-01

    We review recent progress in making the former gedanken experiments of Maxwell's demon [1] into real experiments in a lab. In particular, we focus on realizations based on single-electron tunneling in electronic circuits. We first present how stochastic thermodynamics can be investigated in these circuits. Next we review recent experiments on an electron-based Szilard engine. Finally, we report on experiments on single-electron tunneling-based cooling, overviewing the recent realization of a Coulomb gap refrigerator, as well as an autonomous Maxwell's demon.

  9. Solutions of the cylindrical nonlinear Maxwell equations.

    PubMed

    Xiong, Hao; Si, Liu-Gang; Ding, Chunling; Lü, Xin-You; Yang, Xiaoxue; Wu, Ying

    2012-01-01

    Cylindrical nonlinear optics is a burgeoning research area which describes cylindrical electromagnetic wave propagation in nonlinear media. Finding new exact solutions for different types of nonlinearity and inhomogeneity to describe cylindrical electromagnetic wave propagation is of great interest and meaningful for theory and application. This paper gives exact solutions for the cylindrical nonlinear Maxwell equations and presents an interesting connection between the exact solutions for different cylindrical nonlinear Maxwell equations. We also provide some examples and discussion to show the application of the results we obtained. Our results provide the basis for solving complex systems of nonlinearity and inhomogeneity with simple systems.

  10. Physical Fields Described By Maxwell's Equations

    SciTech Connect

    Ahmetaj, Skender; Veseli, Ahmet; Jashari, Gani

    2007-04-23

    Fields that satisfy Maxwell's equations of motion are analyzed. Investigation carried out in this work, shows that the free electromagnetic field, spinor Dirac's field without mass, spinor Dirac's field with mass, and some other fields are described by the same variational formulation. The conditions that a field be described by Maxwell's equations of motion are given in this work, and some solutions of these conditions are also given. The question arises, which physical objects are formulated by the same or analogous equations of physics.

  11. A Modification to Maxwell's Needle Apparatus

    ERIC Educational Resources Information Center

    Soorya, Tribhuvan N.

    2015-01-01

    Maxwell's needle apparatus is used to determine the shear modulus (?) of the material of a wire of uniform cylindrical cross section. Conventionally, a single observation is taken for each observable, and the value of ? is calculated in a single shot. A modification to the above apparatus is made by varying one of the observables, namely the mass…

  12. Maxwell Equations for Slow-Moving Media

    NASA Astrophysics Data System (ADS)

    Rozov, Andrey

    2015-12-01

    In the present work, the Minkowski equations obtained on the basis of theory of relativity are used to describe electromagnetic fields in moving media. But important electromagnetic processes run under non-relativistic conditions of slow-moving media. Therefore, one should carry out its description in terms of classical mechanics. Hertz derived electrodynamic equations for moving media within the frame of classical mechanics on the basis of the Maxwell theory. His equations disagree with the experimental data concerned with the moving dielectrics. In the paper, a way of description of electromagnetic fields in slow-moving media on the basis of the Maxwell theory within the frame of classical mechanics is offered by combining the Hertz approach and the experimental data concerned with the movement of dielectrics in electromagnetic fields. Received Maxwell equations lack asymmetry in the description of the reciprocal electrodynamic action of a magnet and a conductor and conform to known experimental data. Comparative analysis of the Minkowski and Maxwell models is carried out.

  13. Is Maxwell's Displacement Current a Current?

    ERIC Educational Resources Information Center

    French, A. P.

    2000-01-01

    Discusses in detail the claim that certain well-known physics experiments demonstrate the magnetic field produced by Maxwell's displacement current. Addresses the question of whether the displacement current acts as a source of magnetic field in the same way as a current in a wire would. (Contains 12 references.) (WRM)

  14. Time-Reversible Maxwell’s Demon

    DTIC Science & Technology

    1992-09-01

    Maxwell, Theory of Heat, (Longmans, Green, London 1871), pp. 308- 309. 28 [8] R.P. Feynman , R.B. Leighton, and M. Sands, The FeyzIman Lectures on physics...Quantum Theory and Measurement, edited by J.A. Wheeler and W.H.Zurek, (Princeton University Press, Prince- ton 1983), pp. 539-548. 29 Figure 1: A system of

  15. Maxwell's electromagnetic theory and special relativity.

    PubMed

    Hall, Graham

    2008-05-28

    This paper presents a brief history of electromagnetic theory from ancient times up to the work of Maxwell and the advent of Einstein's special theory of relativity. It is divided into five convenient periods and the intention is to describe these developments for the benefit of a lay scientific audience and with the minimum of technical detail.

  16. Maxwell and the classical wave particle dualism.

    PubMed

    Mendonça, J T

    2008-05-28

    Maxwell's equations are one of the greatest theoretical achievements in physics of all times. They have survived three successive theoretical revolutions, associated with the advent of relativity, quantum mechanics and modern quantum field theory. In particular, they provide the theoretical framework for the understanding of the classical wave particle dualism.

  17. Shock waves: The Maxwell-Cattaneo case

    NASA Astrophysics Data System (ADS)

    Uribe, F. J.

    2016-03-01

    Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M ) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈M1Maxwell-Cattaneo equations cannot be found, and (c) for greater Mach numbers (M >M2) shock wave solutions can be found though they differ significantly from experiments.

  18. What physics is encoded in Maxwell's equations?

    NASA Astrophysics Data System (ADS)

    Kosyakov, B. P.

    2005-08-01

    We reconstruct Maxwell's equations showing that a major part of the information encoded in them is taken from topological properties of spacetime, and the residual information, divorced from geometry, which represents the physical contents of electrodynamics, %these equations, translates into four assumptions:(i) locality; (ii) linearity; %of the dynamical law; (iii) identity of the charge-source and the charge-coupling; and (iv) lack of magnetic monopoles. However, a closer inspection of symmetries peculiar to electrodynamics shows that these assumptions may have much to do with geometry. Maxwell's equations tell us that we live in a three-dimensional space with trivial (Euclidean) topology; time is a one-dimensional unidirectional and noncompact continuum; and spacetime is endowed with a light cone structure readable in the conformal invariance of electrodynamics. Our geometric feelings relate to the fact that Maxwell's equations are built in our brain, hence our space and time orientation, our visualization and imagination capabilities are ensured by perpetual instinctive processes of solving Maxwell's equations. People are usually agree in their observations of angle relations, for example, a right angle is never confused with an angle slightly different from right. By contrast, we may disagree in metric issues, say, a colour-blind person finds the light wave lengths quite different from those found by a man with normal vision. This lends support to the view that conformal invariance of Maxwell's equations is responsible for producing our notion of space. Assuming that our geometric intuition is guided by our innate realization of electrodynamical laws, some abnormal mental phenomena, such as clairvoyance, may have a rational explanation.

  19. Classes of exact Einstein Maxwell solutions

    NASA Astrophysics Data System (ADS)

    Komathiraj, K.; Maharaj, S. D.

    2007-12-01

    We find new classes of exact solutions to the Einstein Maxwell system of equations for a charged sphere with a particular choice of the electric field intensity and one of the gravitational potentials. The condition of pressure isotropy is reduced to a linear, second order differential equation which can be solved in general. Consequently we can find exact solutions to the Einstein Maxwell field equations corresponding to a static spherically symmetric gravitational potential in terms of hypergeometric functions. It is possible to find exact solutions which can be written explicitly in terms of elementary functions, namely polynomials and product of polynomials and algebraic functions. Uncharged solutions are regainable with our choice of electric field intensity; in particular we generate the Einstein universe for particular parameter values.

  20. Altered Maxwell equations in the length gauge

    NASA Astrophysics Data System (ADS)

    Reiss, H. R.

    2013-09-01

    The length gauge uses a scalar potential to describe a laser field, thus treating it as a longitudinal field rather than as a transverse field. This distinction is manifested by the fact that the Maxwell equations that relate to the length gauge are not the same as those for transverse fields. In particular, a source term is necessary in the length-gauge Maxwell equations, whereas the Coulomb-gauge description of plane waves possesses the basic property of transverse fields that they propagate with no source terms at all. This difference is shown to be importantly consequential in some previously unremarked circumstances; and it explains why the Göppert-Mayer gauge transformation does not provide the security that might be expected of full gauge equivalence.

  1. Maxwell electrodynamics subjected to quantum vacuum fluctuations

    SciTech Connect

    Gevorkyan, A. S.; Gevorkyan, A. A.

    2011-06-15

    The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) equations. For a model of 'white noise' fluctuations, using ML equations, a second order partial differential equation is found which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the 'ground state' energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of the vacuum quantum field fluctuations may be constructed on a 6D space-time continuum with a 2D compactified subspace. Their influence on the refraction indexes of vacuum is studied.

  2. Venus - Detailed mapping of Maxwell Montes region

    NASA Astrophysics Data System (ADS)

    Alexandrov, Yu. N.; Crymov, A. A.; Kotelnikov, V. A.; Petrov, G. M.; Rzhiga, O. N.; Sidorenko, A. I.; Sinilo, V. P.; Zakharov, A. I.; Akim, E. L.; Basilevski, A. T.; Kadnichanski, S. A.; Tjuflin, Yu. S.

    1986-03-01

    From October 1983 to July 1984, the north hemisphere of Venus, from latitude 30° to latitude 90°, was mapped by means of the radar imagers and altimeters of the spacecraft Venera 15 and Venera 16. This report presents the results of the radar mapping of the Maxwell Montes region, one of the most interesting features of Venus' surface. A radar mosaic map and contour map have been compiled.

  3. Szilard's Engine: Measurement, Information, and Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Devereux, Michael

    2002-11-01

    Using an isolated measurement process, we calculate the effect measurement has on entropy for the multi-cylinder Szilard engine. We find that the system of cylinders possesses an entropy associated with cylinder total energy states, and that it records information transferred at measurement. Contrary to other's results, we find that the apparatus loses entropy due to measurement. The Second Law of Thermodynamics may be preserved if Maxwell's demon gains entropy moving the engine partition.

  4. Loading relativistic Maxwell distributions in particle simulations

    SciTech Connect

    Zenitani, Seiji

    2015-04-15

    Numerical algorithms to load relativistic Maxwell distributions in particle-in-cell (PIC) and Monte-Carlo simulations are presented. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are proposed in a physically transparent manner. Their acceptance efficiencies are ≈50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.

  5. Maxwell: A new vision of the world

    NASA Astrophysics Data System (ADS)

    Maystre, Daniel

    2014-05-01

    The paper outlines the crucial contributions of James Clerk Maxwell to Physics and more generally to our vision of the world. He achieved 150 years ago a synthesis of the pioneering works in magnetostatics, electrostatics, induction and, by introducing the notion of displacement current, gave birth to Electromagnetics. Then, he deduced the existence of electromagnetic waves and identified light as one of them. Maxwell equations deeply changed a Newtonian conception of the world based on particle interactions by pointing out the vital role of waves in physics. This new conception had a strong influence on the development of quantum physics. Finally, the invariance of light velocity in Galilean frames led to Lorentz transformations, a key step toward the theory of relativity. Par ailleurs, les équations de Maxwell ont profondément changé une conception du monde newtonienne basée sur l'interaction entre particules en révélant le rôle essentiel des ondes en physique, ce qui eut une influence déterminante sur le développement de la physique quantique. Enfin, l'invariance de la vitesse de la lumière dans les repères galiléens a entraîné la découverte des transformations de Lorentz, une étape capitale vers la théorie de la relativité.

  6. Duality relation for the Maxwell system

    NASA Astrophysics Data System (ADS)

    Zolla, F.; Guenneau, S.

    2003-02-01

    This paper is intended to establish a link between the vector Maxwell system for three-dimensional (3D) and 2D finite photonic crystals in the low-frequency limit. For this, we generalize the classical results of Keller and Dykhne (chessboard problem) to periodic media described by piecewise continuous permittivity profiles: our theorem enlights the result of Mendelson (polycrystalline and multiphase media) in the framework of homogenization theory of elliptic operators. In fine, we give illustrative examples by using both integral equation and variational approaches via the so-called method of fictitious charges and finite-element method.

  7. A posteriori error estimates for Maxwell equations

    NASA Astrophysics Data System (ADS)

    Schoeberl, Joachim

    2008-06-01

    Maxwell equations are posed as variational boundary value problems in the function space H(operatorname{curl}) and are discretized by Nedelec finite elements. In Beck et al., 2000, a residual type a posteriori error estimator was proposed and analyzed under certain conditions onto the domain. In the present paper, we prove the reliability of that error estimator on Lipschitz domains. The key is to establish new error estimates for the commuting quasi-interpolation operators recently introduced in J. Schoeberl, Commuting quasi-interpolation operators for mixed finite elements. Similar estimates are required for additive Schwarz preconditioning. To incorporate boundary conditions, we establish a new extension result.

  8. Maxwell's demon based on a single qubit

    NASA Astrophysics Data System (ADS)

    Pekola, J. P.; Golubev, D. S.; Averin, D. V.

    2016-01-01

    We propose and analyze Maxwell's demon based on a single qubit with avoided level crossing. Its operation cycle consists of adiabatic drive to the point of minimum energy separation, measurement of the qubit state, and conditional feedback. We show that the heat extracted from the bath at temperature T can ideally approach the Landauer limit of kBT ln2 per cycle even in the quantum regime. Practical demon efficiency is limited by the interplay of Landau-Zener transitions and coupling to the bath. We suggest that an experimental demonstration of the demon is fully feasible using one of the standard superconducting qubits.

  9. Maxwell's demon. (II) A quantum-theoretic exorcism

    NASA Astrophysics Data System (ADS)

    Gyftopoulos, Elias P.

    2002-05-01

    In Part II of this two-part paper we prove that Maxwell's demon is unable to accomplish his task of sorting air molecules into swift and slow because in air in a thermodynamic equilibrium state there are no such molecules. The proof is based on the principles of a unified quantum theory of mechanics and thermodynamics. The key idea of the unified theory is that von Neumann's concept of a homogeneous ensemble of identical systems, identically prepared, is valid not only for a density operator ρ equal to a projector (every member of the ensemble is assigned the same projector, ρi=| ψi> < ψi|= ρi2, or the same wave function ψ i as any other member) but also for a density operator that is not a projector (every member of the ensemble is assigned the same density operator, ρ>ρ 2, as any other member). So, the latter ensemble is not a statistical mixture of projectors. The broadening of the validity of the homogeneous ensemble is consistent with the quantum-theoretic postulates about observables, measurement results, and value of any observable. In the context of the unified theory, among the many novel results is the theorem that each molecule of a system in a thermodynamic equilibrium state has zero value of momentum, that is, each molecule is at a standstill and, therefore, there are no molecules to be sorted as swift and slow. Said differently, if Maxwell were cognizant of quantum theory, he would not have conceived of the idea of the demon. It is noteworthy that the zero value of momentum is not the result of averaging over different momenta of many molecules. Under the specified conditions, it is the quantum-theoretic value of the momentum of any one molecule, and the same result is valid even if the system consists of only one molecule.

  10. Book Review: Maxwell's Demon 2: Entropy, classical and quantum information, computing. Harvey Leff and Andrew Rex (Eds.); Institute of Physics, Bristol, 2003, 500pp., US 55, ISBN 0750307595

    NASA Astrophysics Data System (ADS)

    Shenker, Orly R.

    2004-09-01

    In 1867, James Clerk Maxwell proposed a perpetuum mobile of the second kind, that is, a counter example for the Second Law of thermodynamics, which came to be known as "Maxwell's Demon." Unlike any other perpetual motion machine, this one escaped attempts by the best scientists and philosophers to show that the Second Law or its statistical mechanical counterparts are universal after all. "Maxwell's demon lives on. After more than 130 years of uncertain life and at least two pronouncements of death, this fanciful character seems more vibrant than ever." These words of Harvey Leff and Andrew Rex (1990), which open their introduction to Maxwell's Demon 2: Entropy, Classical and Quantum Information, Computing (hereafter MD2) are very true: the Demon is as challenging and as intriguing as ever, and forces us to think and rethink about the foundations of thermodynamics and of statistical mechanics.

  11. On Feynman's proof of the Maxwell equations

    NASA Astrophysics Data System (ADS)

    Noyes, H. P.

    1991-03-01

    Dyson has presented a derivation of the free space Maxwell Equations and the Lorentz force starting from Newton's Second Law and the commutation relations between x(sub i), x(sub j), and x(sub k). The proof is attributed to Feynman. The reason why it works is puzzling. The finite and discrete reconciliation between relativity and quantum mechanics offers a less problematic logical chain. The mass ratios are defined using deBroglie wave interference in a theory which necessarily entails the commutation relations. It is shown that this route implies Newton's Third Law. Following Mach, Newton's Second Law then becomes a definition of force, and given this the Lorentz force becomes a definition of the electromagnetic fields. The use of the relativistic Zitterbewegun with the step length h/mc consistently introduces the limiting velocity c into the calculation, and removes a puzzle about dimensions from the Feynman results. By adopting the Wheeler-Feynman point of view that the energy and momenta of massless quanta are defined by the sources and sinks, the inhomogeneous Maxwell equations are derived from quantum particle physics - which Feynman was unable to do - and hence the classical electromagnetic theory was established as a well defined continuum approximation to the fully discrete relativistic quantum mechanics. Exploration of quantum gravity along these lines appears to be promising.

  12. Generalized Maxwell equations and charge conservation censorship

    NASA Astrophysics Data System (ADS)

    Modanese, G.

    2017-02-01

    The Aharonov-Bohm electrodynamics is a generalization of Maxwell theory with reduced gauge invariance. It allows to couple the electromagnetic field to a charge which is not locally conserved, and has an additional degree of freedom, the scalar field S = ∂αAα, usually interpreted as a longitudinal wave component. By reformulating the theory in a compact Lagrangian formalism, we are able to eliminate S explicitly from the dynamics and we obtain generalized Maxwell equation with interesting properties: they give ∂μFμν as the (conserved) sum of the (possibly non-conserved) physical current density jν, and a “secondary” current density iν which is a nonlocal function of jν. This implies that any non-conservation of jν is effectively “censored” by the observable field Fμν, and yet it may have real physical consequences. We give examples of stationary solutions which display these properties. Possible applications are to systems where local charge conservation is violated due to anomalies of the Adler-Bell-Jackiw (ABJ) kind or to macroscopic quantum tunnelling with currents which do not satisfy a local continuity equation.

  13. How Many Maxwell's Demons, and Where?

    NASA Astrophysics Data System (ADS)

    Fanchon, Eric; Neori, Klil Ha-Horesh; Elitzur, Avshalom C.

    Maxwell's demon has been conceived as a tool for challenging the law of entropy increase. Several resolutions of the paradox have been proposed, making it clear that the demon does not violate the second law of thermodynamics. Nevertheless, since recent experiments come close to realizing some variants of Maxwell's demon, it is interesting to revisit it. In this article we first address two questions, left unnoticed despite many years of intensive study: (1) on which side of the door should the demon be located when the door is shut? and (2) how is kinetic energy exchanged between the two compartments due to the demon's sorting? We propose a simple setting which is more realistic than the current versions, in which the demon monitors and accesses both sides of the partition, so as to enable the sorting task. Next we study the impact of this sorting on the molecular kinetic energy exchanges. We show that the temperature difference between compartments grows till the cold part of the gas approaches 0 K. We then emphasize that this setting yields to the familiar resolution of the paradox. In the last part we derive the expression of the average rate of energy flow between the two compartments of the system, based on the new setting proposed.

  14. Comparing Teaching Approaches About Maxwell's Displacement Current

    NASA Astrophysics Data System (ADS)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  15. Maxwell Equations and the Redundant Gauge Degree of Freedom

    ERIC Educational Resources Information Center

    Wong, Chun Wa

    2009-01-01

    On transformation to the Fourier space (k,[omega]), the partial differential Maxwell equations simplify to algebraic equations, and the Helmholtz theorem of vector calculus reduces to vector algebraic projections. Maxwell equations and their solutions can then be separated readily into longitudinal and transverse components relative to the…

  16. Chaotic magnetic fields in Vlasov-Maxwell equilibria

    SciTech Connect

    Ghosh, Abhijit; Janaki, M. S.; Dasgupta, Brahmananda; Bandyopadhyay, Alak

    2014-03-15

    Stationary solutions of Vlasov-Maxwell equations are obtained by exploiting the invariants of single particle motion leading to linear or nonlinear functional relations between current and vector potential. For a specific combination of invariants, it is shown that Vlasov-Maxwell equilibria have an associated Hamiltonian that exhibits chaos.

  17. Maxwell and creation: Acceptance, criticism, and his anonymous publication

    NASA Astrophysics Data System (ADS)

    Marston, Philip L.

    2007-08-01

    Although James Clerk Maxwell's religious views and discussions on atoms having the properties of ``manufactured articles'' have been discussed, some aspects of the responses by his contemporaries to his remarks on creation have been neglected. Various responses quoted here include a book from 1878 by ``Physicus'' (George John Romanes) attributing ``arrogance'' to Maxwell for his inferences. Relevant aspects of the evolution of the perspective of Romanes are noted. A response by B. F. Westcott indicated that Maxwell was the author of a related anonymous publication concerned with what eventually became known as the heat death of the universe. In his teaching to theology students, Westcott, a friend of Maxwell, emphasized Maxwell's reasoning based on the dissipation of energy. There are similarities between Maxwell's perspective on creation and Biblical commentaries by fellow Eranus Club members Westcott and J. B. Lightfoot. Interest in Maxwell's remarks extended into the twentieth century. The principal Baptist chapel attended by Maxwell and his wife when in London in the 1860s is identified and some relevant attributes of the chapel and of its pastor are described.

  18. Environmental Assessment: Military Family Housing Privatization Maxwell Air Force Base

    DTIC Science & Technology

    2005-06-01

    Water Resources) Montgomery Chamber of Commerce George , Randall (President) Montgomery County – City Public Library Montgomery County...Force Base Personnel, Interviewer; Tamara Carroll. Zervos , Spero G. 2001. A Brief History of Maxwell AFB. Maxwell AFB, AL: Air University History...35486- 6999 205-247-3589 Montgomery Chamber of Commerce President Randall George 41 Commerce Street Montgomery, AL 36101 PO Box 79 Montgomery, AL

  19. Post-Newtonian approximation in Maxwell-like form

    SciTech Connect

    Kaplan, Jeffrey D.; Nichols, David A.; Thorne, Kip S.

    2009-12-15

    The equations of the linearized first post-Newtonian approximation to general relativity are often written in 'gravitoelectromagnetic' Maxwell-like form, since that facilitates physical intuition. Damour, Soffel, and Xu (DSX) (as a side issue in their complex but elegant papers on relativistic celestial mechanics) have expressed the first post-Newtonian approximation, including all nonlinearities, in Maxwell-like form. This paper summarizes that DSX Maxwell-like formalism (which is not easily extracted from their celestial mechanics papers), and then extends it to include the post-Newtonian (Landau-Lifshitz-based) gravitational momentum density, momentum flux (i.e. gravitational stress tensor), and law of momentum conservation in Maxwell-like form. The authors and their colleagues have found these Maxwell-like momentum tools useful for developing physical intuition into numerical-relativity simulations of compact binaries with spin.

  20. Loading relativistic Maxwell distributions in particle simulations

    NASA Astrophysics Data System (ADS)

    Zenitani, S.

    2015-12-01

    In order to study energetic plasma phenomena by using particle-in-cell (PIC) and Monte-Carlo simulations, we need to deal with relativistic velocity distributions in these simulations. However, numerical algorithms to deal with relativistic distributions are not well known. In this contribution, we overview basic algorithms to load relativistic Maxwell distributions in PIC and Monte-Carlo simulations. For stationary relativistic Maxwellian, the inverse transform method and the Sobol algorithm are reviewed. To boost particles to obtain relativistic shifted-Maxwellian, two rejection methods are newly proposed in a physically transparent manner. Their acceptance efficiencies are 􏰅50% for generic cases and 100% for symmetric distributions. They can be combined with arbitrary base algorithms.

  1. Fractional vector calculus and fractional Maxwell's equations

    SciTech Connect

    Tarasov, Vasily E.

    2008-11-15

    The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.

  2. The Life of James Clerk Maxwell

    NASA Astrophysics Data System (ADS)

    Campbell, Lewis; Garnett, William

    2010-06-01

    Preface; Part I. Biographical Outline: 1. Birth and parentage; 2. Glenlair - childhood, 1831-1841; 3. Boyhood, 1841-1844; 4. Adolescence, 1844-1847; 5. Opening manhood, 1847-1850; 6. Undergraduate life at Cambridge, 1850-1854; 7. Bachelor-scholar and fellow of Trinity, 1854-1856; 8. Essays at Cambridge, 1853-1856; 9. Death of his father. Professorship at Aberdeen, 1856-1857; 10. Aberdeen. Marriage, 1857-1860; 11. King's College, London. Glenair, 1860-1870; 12. Cambridge, 1871-1879; 13. Illness and death, 1879; 14. Last essays at Cambridge; Part II. Contributions to Science: 1. Experiments on colour vision, and other contributions to optics; 2. Investigations respecting elastic solids; 3. Pure geometry; 4. Mechanics; 5. Saturn's rings; 6. Faraday's lines of force, and Maxwell's theory of the electromagnetic field; 7. Molecular physics; Part III. Poems: 1. Juvenile verses and translations; 2. Occasional pieces; 3. Serio-comic verse; Index.

  3. Solving Maxwell eigenvalue problems for accelerating cavities

    NASA Astrophysics Data System (ADS)

    Arbenz, Peter; Geus, Roman; Adam, Stefan

    2001-02-01

    We investigate algorithms for computing steady state electromagnetic waves in cavities. The Maxwell equations for the strength of the electric field are solved by a mixed method with quadratic finite edge (Nédélec) elements for the field values and corresponding node-based finite elements for the Lagrange multiplier. This approach avoids so-called spurious modes which are introduced if the divergence-free condition for the electric field is not treated properly. To compute a few of the smallest positive eigenvalues and corresponding eigenmodes of the resulting large sparse matrix eigenvalue problems, two algorithms have been used: the implicitly restarted Lanczos algorithm and the Jacobi-Davidson algorithm, both with shift-and-invert spectral transformation. Two-level hierarchical basis preconditioners have been employed for the iterative solution of the resulting systems of equations.

  4. Maxwell's Demon Through the Looking Glass

    NASA Astrophysics Data System (ADS)

    Silagadze, Z. K.

    2007-01-01

    Mechanical Maxwell's demons, such as Smoluchowski's trapdoor and Feynman's ratchet and pawl need external energy source to operate. If you cease to feed a demon the Second Law of thermodynamics will quickly stop its operation. Nevertheless, if the parity is an unbroken symmetry of nature, it may happen that a small modification leads to demons which do not need feeding. Such demons can act like perpetuum mobiles of the second kind: extract heat energy from only one reservoir, use it to do work and be isolated from the rest of ordinary world. Yet the Second Law is not violated because the demons pay their entropy cost in the hidden (mirror) sector of the world by emitting mirror photons.

  5. Algebraically special Einstein-Maxwell fields

    NASA Astrophysics Data System (ADS)

    Van den Bergh, Norbert

    2017-01-01

    The Geroch-Held-Penrose formalism is used to re-analyse algebraically special non-null Einstein-Maxwell fields, aligned as well as non-aligned, in the presence of a possible non-vanishing cosmological constant. A new invariant characterization is given of the García-Plebański and Plebański-Hacyan metrics within the family of aligned solutions and of the Griffiths metrics within the family of the non-aligned solutions. As a corollary also the double alignment of the Debever-McLenaghan `class D' metrics with non-vanishing cosmological constant is shown to be equivalent with the shear-free and geodesic behavior of their Debever-Penrose vectors.

  6. Thermodynamics with information flow: Applications to Maxwell demons and biochemical sensing

    NASA Astrophysics Data System (ADS)

    Horowitz, Jordan

    2015-03-01

    Information is often perceived as an immaterial entity. However, since the birth of statistical physics, it has been argued, based on thought experiments by the likes of Maxwell, that there are physical thermodynamic implications to information manipulation. In this talk, I will discuss a unified framework for the information transfers between continuously interacting systems, describing how information generated in an auxiliary system can be utilized by another as a fuel for an otherwise impossible process. Indeed, while the joint system satisfies the second law, the entropy balance of each system is modified by an information term related to the mutual information between the pair of systems. I will then show how this result incorporates the traditional analysis of Maxwell's demon. In addition, I will use this framework to analyze the thermodynamics and energetics of biological sensory adaptation, employing the biochemical sensing network of E. Coli chemotaxis as a representative example.

  7. Generalized gravitational entropy of interacting scalar field and Maxwell field

    NASA Astrophysics Data System (ADS)

    Huang, Wung-Hong

    2014-12-01

    The generalized gravitational entropy proposed recently by Lewkowycz and Maldacena is extended to the interacting real scalar field and Maxwell field system. Using the BTZ geometry we first investigate the case of free real scalar field and then show a possible way to calculate the entropy of the interacting scalar field. Next, we investigate the Maxwell field system. We exactly solve the wave equation and calculate the analytic value of the generalized gravitational entropy. We also use the Einstein equation to find the effect of backreaction of the Maxwell field on the area of horizon. The associated modified area law is consistent with the generalized gravitational entropy.

  8. Discontinuous Galerkin computation of the Maxwell eigenvalues on simplicial meshes

    NASA Astrophysics Data System (ADS)

    Buffa, Annalisa; Houston, Paul; Perugia, Ilaria

    2007-07-01

    This paper is concerned with the discontinuous Galerkin approximation of the Maxwell eigenproblem. After reviewing the theory developed in [A. Buffa, I. Perugia, Discontinuous Galerkin approximation of the Maxwell eigenproblem, Technical Report 24-PV, IMATI-CNR, Pavia, Italy, 2005 maxwell.pdf>], we present a set of numerical experiments which both validate the theory, and provide further insight regarding the practical performance of discontinuous Galerkin methods, particularly in the case when non-conforming meshes, characterized by the presence of hanging nodes, are employed.

  9. Driven inelastic Maxwell gas in one dimension

    NASA Astrophysics Data System (ADS)

    Prasad, V. V.; Sabhapandit, Sanjib; Dhar, Abhishek; Narayan, Onuttom

    2017-02-01

    A lattice version of the driven inelastic Maxwell gas is studied in one dimension with periodic boundary conditions. Each site i of the lattice is assigned with a scalar "velocity," vi. Nearest neighbors on the lattice interact, with a rate τc-1, according to an inelastic collision rule. External driving, occurring with a rate τw-1, sustains a steady state in the system. A set of closed coupled equations for the evolution of the variance and the two-point correlation is found. Steady-state values of the variance, as well as spatial correlation functions, are calculated. It is shown exactly that the correlation function decays exponentially with distance, and the correlation length for a large system is determined. Furthermore, the spatiotemporal correlation C (x ,t ) = can also be obtained. We find that there is an interior region -x* x* , the correlation function remains the same as the initial form. C (x ,t ) exhibits second-order discontinuity at the transition points x =±x* , and these transition points move away from the x =0 with a constant speed.

  10. An autonomous and reversible Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Barato, A. C.; Seifert, U.

    2013-03-01

    Building on a model introduced by Mandal and Jarzynski (Proc. Natl. Acad. Sci. U.S.A., 109 (2012) 11641), we present a simple version of an autonomous reversible Maxwell's demon. By changing the entropy of a tape consisting of a sequence of bits passing through the demon, the demon can lift a mass using the coupling to a heat bath. Our model becomes reversible by allowing the tape to move in both directions. In this thermodynamically consistent model, total entropy production consists of three terms one of which recovers the irreversible limit studied by MJ. Our demon allows an interpretation in terms of an enzyme transporting and transforming molecules between compartments. Moreover, both genuine equilibrium and a linear response regime with corresponding Onsager coefficients are well defined. Efficiency and efficiency at maximum power are calculated. In linear response, the latter is shown to be bounded by 1/2, if the demon operates as a machine and by 1/3, if it is operated as an eraser.

  11. Two Mathematically Equivalent Versions of Maxwell's Equations

    NASA Astrophysics Data System (ADS)

    Gill, Tepper L.; Zachary, Woodford W.

    2011-01-01

    This paper is a review of the canonical proper-time approach to relativistic mechanics and classical electrodynamics. The purpose is to provide a physically complete classical background for a new approach to relativistic quantum theory. Here, we first show that there are two versions of Maxwell's equations. The new version fixes the clock of the field source for all inertial observers. However now, the (natural definition of the effective) speed of light is no longer an invariant for all observers, but depends on the motion of the source. This approach allows us to account for radiation reaction without the Lorentz-Dirac equation, self-energy (divergence), advanced potentials or any assumptions about the structure of the source. The theory provides a new invariance group which, in general, is a nonlinear and nonlocal representation of the Lorentz group. This approach also provides a natural (and unique) definition of simultaneity for all observers. The corresponding particle theory is independent of particle number, noninvariant under time reversal (arrow of time), compatible with quantum mechanics and has a corresponding positive definite canonical Hamiltonian associated with the clock of the source. We also provide a brief review of our work on the foundational aspects of the corresponding relativistic quantum theory. Here, we show that the standard square-root and Dirac equations are actually two distinct spin- 1/2 particle equations.

  12. Weyl, Dirac and Maxwell Quantum Cellular Automata

    NASA Astrophysics Data System (ADS)

    Bisio, Alessandro; D'Ariano, Giacomo Mauro; Perinotti, Paolo; Tosini, Alessandro

    2015-10-01

    Recent advances on quantum foundations achieved the derivation of free quantum field theory from general principles, without referring to mechanical notions and relativistic invariance. From the aforementioned principles a quantum cellular automata (QCA) theory follows, whose relativistic limit of small wave-vector provides the free dynamics of quantum field theory. The QCA theory can be regarded as an extended quantum field theory that describes in a unified way all scales ranging from an hypothetical discrete Planck scale up to the usual Fermi scale. The present paper reviews the automaton theory for the Weyl field, and the composite automata for Dirac and Maxwell fields. We then give a simple analysis of the dynamics in the momentum space in terms of a dispersive differential equation for narrowband wave-packets. We then review the phenomenology of the free-field automaton and consider possible visible effects arising from the discreteness of the framework. We conclude introducing the consequences of the automaton dispersion relation, leading to a deformed Lorentz covariance and to possible effects on the thermodynamics of ideal gases.

  13. 29. GROUND VIEW OF PIER, LOOKING SOUTHWEST FROM MAXWELL'S RESTAURANT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    29. GROUND VIEW OF PIER, LOOKING SOUTHWEST FROM MAXWELL'S RESTAURANT, SHOWING (LEFT-RIGHT) LIFEGUARD TOWER TO BENT 4 - Huntington Beach Municipal Pier, Pacific Coast Highway at Main Street, Huntington Beach, Orange County, CA

  14. Propagation of ultra-short solitons in stochastic Maxwell's equations

    SciTech Connect

    Kurt, Levent; Schäfer, Tobias

    2014-01-15

    We study the propagation of ultra-short short solitons in a cubic nonlinear medium modeled by nonlinear Maxwell's equations with stochastic variations of media. We consider three cases: variations of (a) the dispersion, (b) the phase velocity, (c) the nonlinear coefficient. Using a modified multi-scale expansion for stochastic systems, we derive new stochastic generalizations of the short pulse equation that approximate the solutions of stochastic nonlinear Maxwell's equations. Numerical simulations show that soliton solutions of the short pulse equation propagate stably in stochastic nonlinear Maxwell's equations and that the generalized stochastic short pulse equations approximate the solutions to the stochastic Maxwell's equations over the distances under consideration. This holds for both a pathwise comparison of the stochastic equations as well as for a comparison of the resulting probability densities.

  15. Complete Vector Spherical Harmonic Expansion for Maxwell's Equations

    ERIC Educational Resources Information Center

    Lambert, R. H.

    1978-01-01

    Conventional expansions of solutions to Maxwell's equations in vector spherical harmonics apply only outside the sources. The complete solution, applying both inside and outside the sources, is given here. Harmonic time dependence is assumed. (Author/GA)

  16. Modeling anisotropic Maxwell-Jüttner distributions: derivation and properties

    NASA Astrophysics Data System (ADS)

    Livadiotis, George

    2016-12-01

    In this paper we develop a model for the anisotropic Maxwell-Jüttner distribution and examine its properties. First, we provide the characteristic conditions that the modeling of consistent and well-defined anisotropic Maxwell-Jüttner distributions needs to fulfill. Then, we examine several models, showing their possible advantages and/or failures in accordance to these conditions. We derive a consistent model, and examine its properties and its connection with thermodynamics. We show that the temperature equals the average of the directional temperature-like components, as it holds for the classical, anisotropic Maxwell distribution. We also derive the internal energy and Boltzmann-Gibbs entropy, where we show that both are maximized for zero anisotropy, that is, the isotropic Maxwell-Jüttner distribution.

  17. Construction of Three Dimensional Solutions for the Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Yefet, A.; Turkel, E.

    1998-01-01

    We consider numerical solutions for the three dimensional time dependent Maxwell equations. We construct a fourth order accurate compact implicit scheme and compare it to the Yee scheme for free space in a box.

  18. New variational principle for the Vlasov-Maxwell equations.

    PubMed

    Brizard, A J

    2000-06-19

    A new Eulerian variational principle is presented for the Vlasov-Maxwell equations. This principle uses constrained variations for the Vlasov distribution in eight-dimensional extended phase space. The standard energy-momentum conservation law is then derived explicitly by the Noether method. This new variational principle can be applied to various reduced Vlasov-Maxwell equations in which fast time scales have been asymptotically eliminated (e.g., low-frequency gyrokinetic theory).

  19. Variational formulations of guiding-center Vlasov-Maxwell theory

    NASA Astrophysics Data System (ADS)

    Brizard, Alain J.; Tronci, Cesare

    2016-06-01

    The variational formulations of guiding-center Vlasov-Maxwell theory based on Lagrange, Euler, and Euler-Poincaré variational principles are presented. Each variational principle yields a different approach to deriving guiding-center polarization and magnetization effects into the guiding-center Maxwell equations. The conservation laws of energy, momentum, and angular momentum are also derived by Noether method, where the guiding-center stress tensor is now shown to be explicitly symmetric.

  20. Maxwell-Garnett effective medium theory: Quantum nonlocal effects

    SciTech Connect

    Moradi, Afshin

    2015-04-15

    We develop the Maxwell-Garnett theory for the effective medium approximation of composite materials with metallic nanoparticles by taking into account the quantum spatial dispersion effects in dielectric response of nanoparticles. We derive a quantum nonlocal generalization of the standard Maxwell-Garnett formula, by means the linearized quantum hydrodynamic theory in conjunction with the Poisson equation as well as the appropriate additional quantum boundary conditions.

  1. Compressible Navier-Stokes Equations with Revised Maxwell's Law

    NASA Astrophysics Data System (ADS)

    Hu, Yuxi; Racke, Reinhard

    2017-03-01

    We investigate the compressible Navier-Stokes equations where the constitutive law for the stress tensor given by Maxwell's law is revised to a system of relaxation equations for two parts of the tensor. The global well-posedness is proved as well as the compatibility with the classical compressible Navier-Stokes system in the sense that, for vanishing relaxation parameters, the solutions to the Maxwell system are shown to converge to solutions of the classical system.

  2. Complex and biofluids: From Maxwell to nowadays

    NASA Astrophysics Data System (ADS)

    Misbah, Chaouqi

    2009-11-01

    Complex fluids are the rule in biology and in many industrial applications. Typical examples are blood, cartilage, and polymer solutions. Unlike water (as well as domestic oils, soft clear drinks, and so on), the law(s) describing the behavior of complex fluids are not yet fully established. The complexity arises from strong coupling between microscopic scales (like the motion of a red blood cell in the case of blood, or a polymer molecule for a polymer solution) and the global scale of the flow (say at the scale of a blood artery, or a channel in laboratory experiments). In this issue entitled Complex and Biofluids a large panel of experimental and theoretical problems of complex fluids is exposed. The topics range from dilute polymer solutions, food products, to biology (blood flow, cell and tissue mechanics). One of the earliest model put forward as an attempt to describe a complex fluid was suggested a long time ago by James Clerk Maxwell (in 1867). Other famous scientists, like Einstein (in 1906), and Taylor (in 1932) have made important contributions to the field, but the topic of complex fluids still continues to pose a formidable challenge to science. This field has known during the past decade an unbelievable upsurge of interest in many branches of science (physics, mechanics, chemistry, biology, medical science, mathematics, and so on). Understanding complex fluids is viewed as one of the biggest challenge of the present century. This synthesis will provide a simple introduction to the topic, summarize the main contribution of this issue, and list major open questions in this field. To cite this article: C. Misbah, C. R. Physique 10 (2009).

  3. CSR Fields: Direct Numerical Solution of the Maxwell___s Equation

    SciTech Connect

    Novokhatski, A.; /SLAC

    2011-06-22

    We discuss the properties of the coherent electromagnetic fields of a very short, ultra-relativistic bunch in a rectangular vacuum chamber inside a bending magnet. The analysis is based on the results of a direct numerical solution of Maxwell's equations together with Newton's equations. We use a new dispersion-free time-domain algorithm which employs a more efficient use of finite element mesh techniques and hence produces self-consistent and stable solutions for very short bunches. We investigate the fine structure of the CSR fields including coherent edge radiation. This approach should be useful in the study of existing and future concepts of particle accelerators and ultrafast coherent light sources. The coherent synchrotron radiation (CSR) fields have a strong action on the beam dynamics of very short bunches, which are moving in the bends of all kinds of magnetic elements. They are responsible for additional energy loss and energy spread; micro bunching and beam emittance growth. These fields may bound the efficiency of damping rings, electron-positron colliders and ultrafast coherent light sources, where high peak currents and very short bunches are envisioned. This is relevant to most high-brightness beam applications. On the other hand these fields together with transition radiation fields can be used for beam diagnostics or even as a powerful resource of THz radiation. A history of the study of CSR and a good collection of references can be found in [1]. Electromagnetic theory suggests several methods on how to calculate CSR fields. The most popular method is to use Lienard-Wiechert potentials. Other approach is to solve numerically the approximate equations, which are a Schrodinger type equation. These numerical methods are described in [2]. We suggest that a direct solution of Maxwell's equations together with Newton's equations can describe the detailed structure of the CSR fields [3].

  4. RESEARCH NOTE: On Maxwell singularities in postglacial rebound

    NASA Astrophysics Data System (ADS)

    Boschi, Lapo; Tromp, Jeroen; O'Connell, Richard J.

    1999-02-01

    We investigate the problem of finding the numerous relaxation times associated with the postglacial rebound of a layered Maxwell earth model. In general, these relaxation times are the roots of a secular polynomial. When a numerical approach is followed, this polynomial can be very ill behaved, with a number of singularities that coincide with the Maxwell times associated with the model rheology. This problem becomes dramatically evident when the rheological profile of the model is continuous or includes a large number of uniform layers (these two cases are basically the same when the solution is computed numerically). In order to understand the physical meaning of such Maxwell singularities, we perform a comparison between the numerical approach and the existing analytical solution to the problem of the postglacial relaxation of an incompressible, self-gravitating, N-layer, spherical Maxwell earth. We show that the analytical method does not suffer from the Maxwell singularity problem, and give a theoretical explanation of the ill behaviour of the secular polynomial computed in numerical studies.

  5. State-relevant Maxwell's equation from Kaluza-Klein theory

    SciTech Connect

    Luan Jing; Ma Yongge; Ma Boqiang

    2007-11-15

    We study a five-dimensional perfect fluid coupled with Kaluza-Klein gravity. By dimensional reduction, a modified form of Maxwell's equation is obtained, which is relevant to the equation of state of the source. Since the relativistic magnetohydrodynamics and the three-dimensional formulation are widely used to study space matter, we derive the modified Maxwell's equations and relativistic magnetohydrodynamics in 3+1 form. We then take an ideal Fermi gas as an example to study the modified effect, which can be visible under high-density or high-energy conditions, while the traditional Maxwell's equation can be regarded as a result in the low density and low temperature limit. We also indicate the possibility to test the state-relevant effect of Kaluza-Klein theory in a telluric laboratory.

  6. TWO-GRID METHODS FOR MAXWELL EIGENVALUE PROBLEMS

    PubMed Central

    ZHOU, J.; HU, X.; ZHONG, L.; SHU, S.; CHEN, L.

    2015-01-01

    Two new two-grid algorithms are proposed for solving the Maxwell eigenvalue problem. The new methods are based on the two-grid methodology recently proposed by Xu and Zhou [Math. Comp., 70 (2001), pp. 17–25] and further developed by Hu and Cheng [Math. Comp., 80 (2011), pp. 1287–1301] for elliptic eigenvalue problems. The new two-grid schemes reduce the solution of the Maxwell eigenvalue problem on a fine grid to one linear indefinite Maxwell equation on the same fine grid and an original eigenvalue problem on a much coarser grid. The new schemes, therefore, save total computational cost. The error estimates reveals that the two-grid methods maintain asymptotically optimal accuracy, and the numerical experiments presented confirm the theoretical results. PMID:26190866

  7. James Clerk Maxwell and the dynamics of astrophysical discs.

    PubMed

    Ogilvie, Gordon I

    2008-05-28

    Maxwell's investigations into the stability of Saturn's rings provide one of the earliest analyses of the dynamics of astrophysical discs. Current research in planetary rings extends Maxwell's kinetic theory to treat dense granular gases of particles undergoing moderately frequent inelastic collisions. Rather than disrupting the rings, local instabilities may be responsible for generating their irregular radial structure. Accretion discs around black holes or compact stars consist of a plasma permeated by a tangled magnetic field and may be compared with laboratory fluids through an analogy that connects Maxwell's researches in electromagnetism and viscoelasticity. A common theme in this work is the appearance of a complex fluid with a dynamical constitutive equation relating the stress in the medium to the history of its deformation.

  8. Force-free Jacobian equilibria for Vlasov-Maxwell plasmas

    SciTech Connect

    Abraham-Shrauner, B.

    2013-10-15

    New analytic force-free Vlasov-Maxwell equilibria for thin current sheets are presented. The magnetic flux densities are expressed in terms of Jacobian elliptic functions of one Cartesian spatial coordinate. The magnetic flux densities reduce to previously reported hyperbolic functions in one limit and sinusoidal functions in another limit of the modulus k. A much wider class of nonlinear force-free Vlasov-Maxwell equilibria open expanded possibilities for modeling of solar system, astrophysical and laboratory plasmas. Modified Maxwellian distribution functions are determined explicitly in terms of Jacobian elliptic functions. Conditions for double peaked distribution functions that could be unstable are developed.

  9. Hamiltonian time integrators for Vlasov-Maxwell equations

    SciTech Connect

    He, Yang; Xiao, Jianyuan; Zhang, Ruili; Liu, Jian; Qin, Hong; Sun, Yajuan

    2015-12-15

    Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature.

  10. Thermodynamics of a Physical Model Implementing a Maxwell Demon

    NASA Astrophysics Data System (ADS)

    Strasberg, Philipp; Schaller, Gernot; Brandes, Tobias; Esposito, Massimiliano

    2013-01-01

    We present a physical implementation of a Maxwell demon which consists of a conventional single electron transistor (SET) capacitively coupled to another quantum dot detecting its state. Altogether, the system is described by stochastic thermodynamics. We identify the regime where the energetics of the SET is not affected by the detection, but where its coarse-grained entropy production is shown to contain a new contribution compared to the isolated SET. This additional contribution can be identified as the information flow generated by the “Maxwell demon” feedback in an idealized limit.

  11. Hamiltonian time integrators for Vlasov-Maxwell equations

    NASA Astrophysics Data System (ADS)

    He, Yang; Qin, Hong; Sun, Yajuan; Xiao, Jianyuan; Zhang, Ruili; Liu, Jian

    2015-12-01

    Hamiltonian time integrators for the Vlasov-Maxwell equations are developed by a Hamiltonian splitting technique. The Hamiltonian functional is split into five parts, which produces five exactly solvable subsystems. Each subsystem is a Hamiltonian system equipped with the Morrison-Marsden-Weinstein Poisson bracket. Compositions of the exact solutions provide Poisson structure preserving/Hamiltonian methods of arbitrary high order for the Vlasov-Maxwell equations. They are then accurate and conservative over a long time because of the Poisson-preserving nature.

  12. Maxwell boundary condition and velocity dependent accommodation coefficient

    SciTech Connect

    Struchtrup, Henning

    2013-11-15

    A modification of Maxwell's boundary condition for the Boltzmann equation is developed that allows to incorporate velocity dependent accommodation coefficients into the microscopic description. As a first example, it is suggested to consider the wall-particle interaction as a thermally activated process with three parameters. A simplified averaging procedure leads to jump and slip boundary conditions for hydrodynamics. Coefficients for velocity slip, temperature jump, and thermal transpiration flow are identified and compared with those resulting from the original Maxwell model and the Cercignani-Lampis model. An extension of the model leads to temperature dependent slip and jump coefficients.

  13. Information driven current in a quantum Maxwell demon

    NASA Astrophysics Data System (ADS)

    Deffner, Sebastian

    2014-03-01

    We describe a minimal model of a quantum Maxwell demon obeying Hamiltonian dynamics. The model is solved exactly, and we analyze its steady-state behavior. We find that writing information to a quantum memory induces a probability current through the demon, which is the quantum analog of the classical Maxwell demon's action. Our model offers a simple and pedagogical paradigm for investigating the thermodynamics of quantum information processing. We acknowledge financial support by a fellowship within the postdoc-program of the German Academic Exchange Service (DAAD, contract No D/11/40955) and from the National Science Foundation (USA) under grant DMR-1206971.

  14. Multiparticle quantum Szilard engine with optimal cycles assisted by a Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Cai, C. Y.; Dong, H.; Sun, C. P.

    2012-03-01

    We present a complete-quantum description of a multiparticle Szilard engine that consists of a working substance and a Maxwell's demon. The demon is modeled as a multilevel quantum system with specific quantum control, and the working substance consists of identical particles obeying Bose-Einstein or Fermi-Dirac statistics. In this description, a reversible scheme to erase the demon's memory by a lower-temperature heat bath is used. We demonstrate that (1) the quantum control of the demon can be optimized for a single-particle Szilard engine so that the efficiency of the demon-assisted thermodynamic cycle could reach the Carnot cycle's efficiency and (2) the low-temperature behavior of the working substance is very sensitive to the quantum statistics of the particles and the insertion position of the partition.

  15. Mixed weak-perturbative solution method for Maxwell's equations of diffusion with Müller's partial stress tensor in the low velocity limit

    NASA Astrophysics Data System (ADS)

    Faliagas, A. C.

    2016-03-01

    Maxwell's theory of multicomponent diffusion and subsequent extensions are based on systems of mass and momentum conservation equations. The partial stress tensor, which is involved in these equations, is expressed in terms of the gradients of velocity fields by statistical and continuum mechanical methods. We propose a method for the solution of Maxwell's equations of diffusion coupled with Müller's expression for the partial stress tensor. The proposed method consists in a singular perturbation process, followed by a weak (finite element) analysis of the resulting PDE systems. The singularity involved in the obtained equations was treated by a special technique, by which lower-order systems were supplemented by proper combinations of higher-order equations. The method proved particularly efficient for the solution of the Maxwell-Müller system, eventually reducing the number of unknown fields to that of the classical Navier-Stokes/Fick system. It was applied to the classical Stefan tube problem and the Hagen-Poiseuille flow in a hollow-fiber membrane tube. Numerical results for these problems are presented, and compared with the Navier-Stokes/Fick approximation. It is shown that the 0-th order term of the Maxwell-Müller equations differs from a properly formulated Navier-Stokes/Fick system, by a numerically insignificant amount. Numerical results for 1st-order terms indicate a good agreement of the classical approximation (with properly formulated Navier-Stokes and Fick's equations) with the Maxwell-Müller system, in the studied cases.

  16. Maxwell-Higgs equation on higher dimensional static curved spacetimes

    SciTech Connect

    Mulyanto; Akbar, Fiki Taufik Gunara, Bobby Eka

    2015-09-30

    In this paper we consider a class of solutions of Maxwell-Higgs equation in higher dimensional static curved spacetimes called Schwarzchild de-Sitter spacetimes. We obtain the general form of the electric fields and magnetic fields in background Schwarzchild de-Sitter spacetimes. However, determining the interaction between photons with the Higgs scalar fields is needed further studies.

  17. Mechanic-Like Resonance in the Maxwell-Bloch Equations

    ERIC Educational Resources Information Center

    Meziane, Belkacem

    2008-01-01

    We show that, in their unstable regime of operation, the "Maxwell-Bloch" equations that describe light-matter interactions inside a bad-cavity-configured laser carry the same resonance properties as any externally driven mechanic or electric oscillator. This finding demonstrates that the nonlinearly coupled laser equations belong to the same…

  18. Comparing Teaching Approaches about Maxwell's Displacement Current

    ERIC Educational Resources Information Center

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-01-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment…

  19. A Generalized Mass Lumping Scheme for Maxwell's Wave Equation

    SciTech Connect

    Fisher, A; White, D; Rodrigue, G

    2004-01-15

    We are interested in the high order Vector Finite Element Method (VFEM) [1] solution to Maxwell's wave equation on both orthogonal and non-orthogonal meshes. This method discretizes the wave equation in the following manner, where M is the edge mass matrix and K is the edge stiffness matrix created using classical Nedelec edge elements.

  20. Plane wave (curl; Ω) conforming finite elements for Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Ledger, P. D.; Morgan, K.; Hassan, O.; Weatherill, N. P.

    This paper proposes a discretisation of Maxwell's equations which combines the popular edge elements of Nédélec with expansions of plane waves. The method is applied to simple two dimensional electromagnetic wave propagation and scattering simulations and issues of accuracy and matrix conditioning are investigated.

  1. Entanglement entropy of a Maxwell field on the sphere

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Huerta, Marina

    2016-05-01

    We compute the logarithmic coefficient of the entanglement entropy on a sphere for a Maxwell field in d =3 +1 dimensions. In spherical coordinates the problem decomposes into one-dimensional ones along the radial coordinate for each angular momentum. We show that the entanglement entropy of a Maxwell field is equivalent to one of two identical massless scalars from which the mode of l =0 has been removed. This shows the relation clogM=2 (clogS-clogSl =0) between the logarithmic coefficient in the entropy for a Maxwell field clogM , the one for a d =3 +1 massless scalar clogS , and the logarithmic coefficient clogSl =0 for a d =1 +1 scalar with a Dirichlet boundary condition at the origin. Using the accepted values for these coefficients clogS=-1 /90 and clogSl =0=1 /6 , we get clogM=-16 /45 , which coincides with Dowker's calculation, but does not match the coefficient -31/45 in the trace anomaly for a Maxwell field. We have numerically evaluated these three numbers clogM , clogS and clogSl =0, verifying the relation, as well as checked that they coincide with the corresponding logarithmic term in mutual information of two concentric spheres.

  2. Radiation and Maxwell Stress Stabilization of Liquid Bridges

    NASA Technical Reports Server (NTRS)

    Marr-Lyon, M. J.; Thiessen, D. B.; Blonigen, F. J.; Marston, P. L.

    1999-01-01

    The use of both acoustic radiation stress and the Maxwell stress to stabilize liquid bridges is reported. Acoustic radiation stress arises from the time-averaged acoustic pressure at the surface of an object immersed in a sound field. Both passive and active acoustic stabilization schemes as well as an active electrostatic method are examined.

  3. A Basic Program for Calculating the Stuart-Maxwell Test.

    ERIC Educational Resources Information Center

    Powers, Stephen; Gose, Kenneth C.

    1986-01-01

    A BASIC computer program is described which computes the Stuart-Maxwell test with its chi-square value and associate probability level. Following a significant chi-square test, the user has the option of performing multiple comparisons using McNemar's test for the significance of change. (Author)

  4. How to Obtain the Covariant Form of Maxwell's Equations from the Continuity Equation

    ERIC Educational Resources Information Center

    Heras, Jose A.

    2009-01-01

    The covariant Maxwell equations are derived from the continuity equation for the electric charge. This result provides an axiomatic approach to Maxwell's equations in which charge conservation is emphasized as the fundamental axiom underlying these equations.

  5. Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory

    ERIC Educational Resources Information Center

    Tweney, Ryan D.

    2011-01-01

    James Clerk Maxwell "translated" Michael Faraday's experimentally-based field theory into the mathematical representation now known as "Maxwell's Equations." Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other…

  6. 77 FR 65403 - Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New Mexico...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... to be culturally affiliated with the human remains may contact the Maxwell Museum of Anthropology.... Heather Edgar, Maxwell Museum of Anthropology, MSC01 1050, University of New Mexico, Albuquerque, NM...

  7. Analysis of an Incompressible Navier-Stokes-Maxwell-Stefan System

    NASA Astrophysics Data System (ADS)

    Chen, Xiuqing; Jüngel, Ansgar

    2015-12-01

    The Maxwell-Stefan equations for the molar fluxes, supplemented by the incompressible Navier-Stokes equations governing the fluid velocity dynamics, are analyzed in bounded domains with no-flux boundary conditions. The system models the dynamics of a multicomponent gaseous mixture under isothermal conditions. The global-in-time existence of bounded weak solutions to the strongly coupled model and their exponential decay to the homogeneous steady state are proved. The mathematical difficulties are due to the singular Maxwell-Stefan diffusion matrix, the cross-diffusion terms, and the different molar masses of the fluid components. The key idea of the proof is the use of a new entropy functional and entropy variables, which allows for a proof of positive lower and upper bounds of the mass densities without the use of a maximum principle.

  8. Computational modeling of femtosecond optical solitons from Maxwell's equations

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Taflove, Allen; Joseph, Rose M.; Hagness, Susan C.

    1992-01-01

    An algorithm is developed that permits the direct time integration of full-vector nonlinear Maxwell's equations. This capability permits the modeling of both linear and nonlinear instantaneous and dispersive effects in the electric polarization in material media. The modeling of the optical carrier is retained. The fundamental innovation is to notice that it is possible to treat the linear and nonlinear convolution integrals, which describe the dispersion, as new dependent variables. A coupled system of nonlinear second-order ordinary differential equations can then be derived for the linear and nonlinear convolution integrals, by differentiating them in the time domain. These equations, together with Maxwell's equations, are solved to determine the electromagnetic fields in nonlinear dispersive media. Results are presented of calculations in one dimension of the propagation and collision of femtosecond electromagnetic solitons that retain the optical carrier, taking into account as the Kerr and Raman interactions.

  9. Algorithm development for Maxwell's equations for computational electromagnetism

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.

    1990-01-01

    A new algorithm has been developed for solving Maxwell's equations for the electromagnetic field. It solves the equations in the time domain with central, finite differences. The time advancement is performed implicitly, using an alternating direction implicit procedure. The space discretization is performed with finite volumes, using curvilinear coordinates with electromagnetic components along those directions. Sample calculations are presented of scattering from a metal pin, a square and a circle to demonstrate the capabilities of the new algorithm.

  10. Symplectic discretization for spectral element solution of Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Zhao, Yanmin; Dai, Guidong; Tang, Yifa; Liu, Qinghuo

    2009-08-01

    Applying the spectral element method (SEM) based on the Gauss-Lobatto-Legendre (GLL) polynomial to discretize Maxwell's equations, we obtain a Poisson system or a Poisson system with at most a perturbation. For the system, we prove that any symplectic partitioned Runge-Kutta (PRK) method preserves the Poisson structure and its implied symplectic structure. Numerical examples show the high accuracy of SEM and the benefit of conserving energy due to the use of symplectic methods.

  11. A Modified Szilard's Engine: Measurement, Information, and Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Devereux, Michael

    2004-03-01

    Using an isolated measurement process, I've calculated the effect measurement has on entropy for the multi-cylinder Szilard engine. This calculation shows that the system of cylinders possesses an entropy associated with cylinder total energy states, and that it records information transferred at measurement. Contrary to other's results, I've found that the apparatus loses entropy due to measurement. The Second Law of Thermodynamics may be preserved if Maxwell's demon gains entropy moving the engine partition.

  12. Transient growth in stable linearized Vlasov-Maxwell plasmas

    SciTech Connect

    Podesta, J. J.

    2010-12-15

    Large amplitude transient growth of kinetic scale perturbations in stable collisionless magnetized plasmas has recently been demonstrated using a linearized Landau fluid model. Initial perturbations with lengthscales of the order of the ion gyroradius were shown to have transient timescales that in some cases were long compared to the ion gyroperiod, {Omega}{sub i}t>>1. Moreover, it was suggested that such perturbations are not rare but instead form a large class within the set of all possible initial conditions. For collisionless plasmas, the Vlasov-Maxwell equations provide a more complete description of kinetic physics and the existence of transient growth of solutions for the linearized Vlasov-Maxwell system is an interesting question. The existence of transient growth of solutions is demonstrated here for a special case of the Vlasov-Maxwell equations, namely, the one dimensional Vlasov-Poisson system. The analysis is different from the standard approach of nonmodal analysis since the initial value problem is described by a Volterra integral equation of the second kind, reflecting the fact that the time evolution of the system depends on the memory of the state from time zero through time t. For the case of a thermal equilibrium plasma, it is shown how initial conditions may be constructed to obtain solutions that grow linearly in time; the duration of this growth is the time required for a thermal electron to traverse the wavelength of the initial perturbation, a timescale that can last for many plasma periods 2{pi}/{omega}{sub pe}, thus demonstrating the existence of transient growth of solutions for the linearized Vlasov-Poisson system. The results suggest that the phenomenon of transient growth may be a common feature of the linearized Vlasov-Maxwell system as well as for Landau fluid models.

  13. Derivation of special relativity from Maxwell and Newton.

    PubMed

    Dunstan, D J

    2008-05-28

    Special relativity derives directly from the principle of relativity and from Newton's laws of motion with a single undetermined parameter, which is found from Faraday's and Ampère's experimental work and from Maxwell's own introduction of the displacement current to be the -c(-2) term in the Lorentz transformations. The axiom of the constancy of the speed of light is quite unnecessary. The behaviour and the mechanism of the propagation of light are not at the foundations of special relativity.

  14. Class of Einstein-Maxwell-dilaton-axion space-times

    SciTech Connect

    Matos, Tonatiuh; Miranda, Galaxia; Sanchez-Sanchez, Ruben; Wiederhold, Petra

    2009-06-15

    We use the harmonic maps ansatz to find exact solutions of the Einstein-Maxwell-dilaton-axion (EMDA) equations. The solutions are harmonic maps invariant to the symplectic real group in four dimensions Sp(4,R){approx}O(5). We find solutions of the EMDA field equations for the one- and two-dimensional subspaces of the symplectic group. Specially, for illustration of the method, we find space-times that generalize the Schwarzschild solution with dilaton, axion, and electromagnetic fields.

  15. The Inverse Source Problem for Maxwell’s Equations

    DTIC Science & Technology

    2006-10-01

    if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT...currents from surface electroencephalographic measurements. The application is to prosthesis control . 15. SUBJECT TERMS INVERSE, MAXWELL...measurements could be used to diagnose abnormalities in the brain and also to allow the control of prosthetic limbs. From the point of view of mathematical

  16. Reanalyzing the Ampère-Maxwell Law

    NASA Astrophysics Data System (ADS)

    Hill, S. Eric

    2011-09-01

    In a recent TPT article, I addressed a common miscommunication about Faraday's law, namely, that introductory texts often say the law expresses a causal relationship between the magnetic fields time variation and the electric fields circulation. In that article, I demonstrated that these field behaviors share a common cause in a time-varying current density. From that, many readers may have rightly guessed at a symmetric conclusion: while the Ampère-Maxwell law is commonly said to express a causal relation between the electric fields time variation and the magnetic fields circulation, these field behaviors share a distinct, common cause. Together, Faraday's law and the Ampère-Maxwell law constitute half of Maxwell's laws that form a foundation for almost all of electricity and magnetism. By misrepresenting these two laws, introductory texts not only present students with unnecessary conceptual hurdles early in their physics educations but also leave them with enduring misunderstandings about the very foundation of electricity and magnetism. Fortunately, compared to what is commonly taught, the actual cause of these field variations is conceptually simpler and more consistent with what the students will have already learned in the introductory texts' own earlier chapters.

  17. Explicit and implicit ode solvers using Krylov subspace optimization: Application to the diffusion equation and parabolic Maxwell`s system

    SciTech Connect

    Druskin, V.; Knizhnerman, L.

    1994-12-31

    The authors solve the Cauchy problem for an ODE system Au + {partial_derivative}u/{partial_derivative}t = 0, u{vert_bar}{sub t=0} = {var_phi}, where A is a square real nonnegative definite symmetric matrix of the order N, {var_phi} is a vector from R{sup N}. The stiffness matrix A is obtained due to semi-discretization of a parabolic equation or system with time-independent coefficients. The authors are particularly interested in large stiff 3-D problems for the scalar diffusion and vectorial Maxwell`s equations. First they consider an explicit method in which the solution on a whole time interval is projected on a Krylov subspace originated by A. Then they suggest another Krylov subspace with better approximating properties using powers of an implicit transition operator. These Krylov subspace methods generate optimal in a spectral sense polynomial approximations for the solution of the ODE, similar to CG for SLE.

  18. Algorithmic information content, Church-Turing thesis, physical entropy, and Maxwell's demon

    SciTech Connect

    Zurek, W.H.

    1990-01-01

    Measurements convert alternative possibilities of its potential outcomes into the definiteness of the record'' -- data describing the actual outcome. The resulting decrease of statistical entropy has been, since the inception of the Maxwell's demon, regarded as a threat to the second law of thermodynamics. For, when the statistical entropy is employed as the measure of the useful work which can be extracted from the system, its decrease by the information gathering actions of the observer would lead one to believe that, at least from the observer's viewpoint, the second law can be violated. I show that the decrease of ignorance does not necessarily lead to the lowering of disorder of the measured physical system. Measurements can only convert uncertainty (quantified by the statistical entropy) into randomness of the outcome (given by the algorithmic information content of the data). The ability to extract useful work is measured by physical entropy, which is equal to the sum of these two measures of disorder. So defined physical entropy is, on the average, constant in course of the measurements carried out by the observer on an equilibrium system. 27 refs., 6 figs.

  19. Jump conditions for Maxwell equations and their consequences

    NASA Astrophysics Data System (ADS)

    Satapathy, Sikhanda; Hsieh, Kuota

    2013-01-01

    We derived the jump conditions for Faraday's induction law at the interface of two contacting bodies in both Eulerian and Lagrangian descriptions. An algorithm to implement the jump conditions in the potential formulation of Maxwell equation is presented. Calculations show that the use of the correct jump conditions leads to good agreement with experimental data, whereas the use of incorrect jump conditions can lead to severe inaccuracies in the computational results. Our derivation resolves the jump condition discrepancy found in the literature and is validated with experimental results.

  20. Maxwell Equation for the Coupled Spin-Charge Wave Propagation

    SciTech Connect

    Bernevig, B.Andrei; Yu, Xiaowei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-01-15

    We show that the dissipationless spin current in the ground state of the Rashba model gives rise to a reactive coupling between the spin and charge propagation, which is formally identical to the coupling between the electric and the magnetic fields in the 2 + 1 dimensional Maxwell equation. This analogy leads to a remarkable prediction that a density packet can spontaneously split into two counter propagation packets, each carrying the opposite spins. In a certain parameter regime, the coupled spin and charge wave propagates like a transverse 'photon'. We propose both optical and purely electronic experiments to detect this effect.

  1. On the physical meaning of the Robinson Trautman Maxwell fields

    NASA Astrophysics Data System (ADS)

    Kozameh, Carlos; Newman, E. T.; Silva-Ortigoza, Gilberto

    2006-12-01

    We study the Robinson Trautman Maxwell fields in two closely related coordinate systems, the original Robinson Trautman (RT) coordinates (in a more general context, often referred to as NU coordinates) and Bondi coordinates. In particular, we identify one of the RT variables as a velocity and then from the Bondi energy momentum 4-vector, we find kinematic expressions for the mass and momentum in terms of this velocity. From these kinematic expressions and the energy momentum loss equation we obtain surprising equations of motion for 'the centre of mass' of the source where the motion takes place in the four-dimensional Poincare translation sub-group of the BMS group.

  2. How an autonomous quantum Maxwell demon can harness correlated information

    NASA Astrophysics Data System (ADS)

    Chapman, Adrian; Miyake, Akimasa

    2015-12-01

    We study an autonomous quantum system which exhibits refrigeration under an information-work trade-off like a Maxwell demon. The system becomes correlated as a single "demon" qubit interacts sequentially with memory qubits while in contact with two heat reservoirs of different temperatures. Using strong subadditivity of the von Neumann entropy, we derive a global Clausius inequality to show thermodynamic advantages from access to correlated information. It is demonstrated, in a matrix product density operator formalism, that our demon can simultaneously realize refrigeration against a thermal gradient and erasure of information from its memory, which is impossible without correlations. The phenomenon can be even enhanced by the presence of quantum coherence.

  3. Lie-Poisson bifurcations for the Maxwell-Bloch equations

    SciTech Connect

    David, D.

    1990-01-01

    We present a study of the set of Maxwell-Bloch equations on R{sup 3} from the point of view of Hamiltonian dynamics. These equations are shown to be bi-Hamiltonian, on the one hand, and to possess several inequivalent Lie-Poisson structures, on the other hand, parametrized by the group SL(2,R). Each structure is characterized by a particular distinguished function. The level sets of this function provide two-dimensional surfaces onto which the motion takes various symplectic forms. 4 refs.

  4. Climate Controlled Sedimentation in Maxwell Bay, King George Island, Antarctica

    NASA Astrophysics Data System (ADS)

    Hass, H.; Kuhn, G.; Wittenberg, N.; Woelfl, A.; Betzler, C.

    2012-12-01

    Climatic change in Antarctica is strongest over the Antarctic Peninsula where in places the annual mean temperatures increased by 0.5 K per decade through the past 60 years. The impact of this warming trend is clearly visible in the form of retreating glaciers and melting ice sheets, loss of sea ice and strong meltwater discharge into the coastal zone. While it is generally accepted that the rapidity of the present climate change bears a significant anthropogenic aspect, it is not clear whether the effects caused by the warming trend are exceptional and unprecedented or whether the reaction of the environment is similar to that of earlier climate phases such as the Medieval Warm Period (MWP) about 1,000 years ago. One of the major goals of the joint international research project IMCOAST is to investigate the strength of the recent warming trend and its impact on the marine environment of the West Antarctic Peninsula (WAP). The study we present here reveals the Upper Holocene climatic history based on high-resolution sediment cores from Maxwell Bay (King George Island, WAP) and information on the actual processes triggered or altered by the recent warming trend based on sedimentologic and hydroacoustic investigations in Potter Cove, a tributary fjord to Maxwell Bay. Long sediment cores from Maxwell Bay reveal grain-size changes that can be linked to cold and warm phases such as the Little Ice Age (LIA) and the MWP. Generally, warm phases are finer grained than cold phases as a result of longer and stronger melting processes during the warm phases. It is suggested that meltwater plumes carry fine-grained sediment out of the surrounding fjords into Maxwell Bay where it settles in suitable areas to produce sediments that have a modal value around 16 μm. This mode is largely absent in sediments deposited during e.g. the LIA. However, post LIA sediments are depleted in the 16 μm-mode sediment suggesting slightly different conditions during the last century. One reason

  5. Statistical mechanics and thermodynamics: A Maxwellian view

    NASA Astrophysics Data System (ADS)

    Myrvold, Wayne C.

    One finds, in Maxwell's writings on thermodynamics and statistical physics, a conception of the nature of these subjects that differs in interesting ways from the way they are usually conceived. In particular, though-in agreement with the currently accepted view-Maxwell maintains that the second law of thermodynamics, as originally conceived, cannot be strictly true, the replacement he proposes is different from the version accepted by most physicists today. The modification of the second law accepted by most physicists is a probabilistic one: although statistical fluctuations will result in occasional spontaneous differences in temperature or pressure, there is no way to predictably and reliably harness these to produce large violations of the original version of the second law. Maxwell advocates a version of the second law that is strictly weaker; the validity of even this probabilistic version is of limited scope, limited to situations in which we are dealing with large numbers of molecules en masse and have no ability to manipulate individual molecules. Connected with this is his conception of the thermodynamic concepts of heat, work, and entropy; on the Maxwellian view, these are concept that must be relativized to the means we have available for gathering information about and manipulating physical systems. The Maxwellian view is one that deserves serious consideration in discussions of the foundation of statistical mechanics. It has relevance for the project of recovering thermodynamics from statistical mechanics because, in such a project, it matters which version of the second law we are trying to recover.

  6. Application of Block Krylov Subspace Spectral Methods to Maxwell's Equations

    SciTech Connect

    Lambers, James V.

    2009-10-08

    Ever since its introduction by Kane Yee over forty years ago, the finite-difference time-domain (FDTD) method has been a widely-used technique for solving the time-dependent Maxwell's equations. This paper presents an alternative approach to these equations in the case of spatially-varying electric permittivity and/or magnetic permeability, based on Krylov subspace spectral (KSS) methods. These methods have previously been applied to the variable-coefficient heat equation and wave equation, and have demonstrated high-order accuracy, as well as stability characteristic of implicit time-stepping schemes, even though KSS methods are explicit. KSS methods for scalar equations compute each Fourier coefficient of the solution using techniques developed by Gene Golub and Gerard Meurant for approximating elements of functions of matrices by Gaussian quadrature in the spectral, rather than physical, domain. We show how they can be generalized to coupled systems of equations, such as Maxwell's equations, by choosing appropriate basis functions that, while induced by this coupling, still allow efficient and robust computation of the Fourier coefficients of each spatial component of the electric and magnetic fields. We also discuss the implementation of appropriate boundary conditions for simulation on infinite computational domains, and how discontinuous coefficients can be handled.

  7. A Maxwell elasto-brittle rheology for sea ice modelling

    NASA Astrophysics Data System (ADS)

    Dansereau, Véronique; Weiss, Jérôme; Saramito, Pierre; Lattes, Philippe

    2016-07-01

    A new rheological model is developed that builds on an elasto-brittle (EB) framework used for sea ice and rock mechanics, with the intent of representing both the small elastic deformations associated with fracturing processes and the larger deformations occurring along the faults/leads once the material is highly damaged and fragmented. A viscous-like relaxation term is added to the linear-elastic constitutive law together with an effective viscosity that evolves according to the local level of damage of the material, like its elastic modulus. The coupling between the level of damage and both mechanical parameters is such that within an undamaged ice cover the viscosity is infinitely large and deformations are strictly elastic, while along highly damaged zones the elastic modulus vanishes and most of the stress is dissipated through permanent deformations. A healing mechanism is also introduced, counterbalancing the effects of damaging over large timescales. In this new model, named Maxwell-EB after the Maxwell rheology, the irreversible and reversible deformations are solved for simultaneously; hence drift velocities are defined naturally. First idealized simulations without advection show that the model reproduces the main characteristics of sea ice mechanics and deformation: strain localization, anisotropy, intermittency and associated scaling laws.

  8. A Test of Maxwell's Z Model Using Inverse Modeling

    NASA Technical Reports Server (NTRS)

    Anderson, J. L. B.; Schultz, P. H.; Heineck, T.

    2003-01-01

    In modeling impact craters a small region of energy and momentum deposition, commonly called a "point source", is often assumed. This assumption implies that an impact is the same as an explosion at some depth below the surface. Maxwell's Z Model, an empirical point-source model derived from explosion cratering, has previously been compared with numerical impact craters with vertical incidence angles, leading to two main inferences. First, the flowfield center of the Z Model must be placed below the target surface in order to replicate numerical impact craters. Second, for vertical impacts, the flow-field center cannot be stationary if the value of Z is held constant; rather, the flow-field center migrates downward as the crater grows. The work presented here evaluates the utility of the Z Model for reproducing both vertical and oblique experimental impact data obtained at the NASA Ames Vertical Gun Range (AVGR). Specifically, ejection angle data obtained through Three-Dimensional Particle Image Velocimetry (3D PIV) are used to constrain the parameters of Maxwell's Z Model, including the value of Z and the depth and position of the flow-field center via inverse modeling.

  9. A multigrid method for variable coefficient Maxwell's equations

    SciTech Connect

    Jones, J E; Lee, B

    2004-05-13

    This paper presents a multigrid method for solving variable coefficient Maxwell's equations. The novelty in this method is the use of interpolation operators that do not produce multilevel commutativity complexes that lead to multilevel exactness. Rather, the effects of multilevel exactness are built into the level equations themselves--on the finest level using a discrete T-V formulation, and on the coarser grids through the Galerkin coarsening procedure of a T-V formulation. These built-in structures permit the levelwise use of an effective hybrid smoother on the curl-free near-nullspace components, and these structures permit the development of interpolation operators for handling the curl-free and divergence-free error components separately, with the resulting block diagonal interpolation operator not satisfying multilevel commutativity but having good approximation properties for both of these error components. Applying operator-dependent interpolation for each of these error components leads to an effective multigrid scheme for variable coefficient Maxwell's equations, where multilevel commutativity-based methods can degrade. Numerical results are presented to verify the effectiveness of this new scheme.

  10. All extremal instantons in Einstein-Maxwell-dilaton-axion theory

    NASA Astrophysics Data System (ADS)

    Azreg-Aïnou, Mustapha; Clément, Gérard; Gal'Tsov, Dmitri V.

    2011-11-01

    We construct explicitly all extremal instanton solutions to N=4, D=4 supergravity truncated to one vector field (Einstein-Maxwell-dilaton-axion theory). These correspond to null geodesics of the target space of the sigma-model G/H=Sp(4,R)/GL(2,R) obtained by compactification of four-dimensional Euclidean Einstein-Maxwell-dilaton-axion on a circle. They satisfy a no-force condition in terms of the asymptotic charges and part of them (corresponding to nilpotent orbits of the Sp(4,R) U-duality) are presumably supersymmetric. The space of finite action solutions is found to be unexpectedly large and includes, besides the Euclidean versions of known Lorentzian solutions, a number of new asymptotically locally flat instantons endowed with electric, magnetic, dilaton and axion charges. We also describe new classes of charged asymptotically locally Euclidean instantons as well as some exceptional solutions. Our classification scheme is based on the algebraic classification of matrix generators according to their rank, according to the nature of the charge vectors, and according to the number of independent harmonic functions with unequal charges. Besides the nilpotent orbits of G, we find solutions which satisfy the asymptotic no-force condition, but are not supersymmetric. The renormalized on-shell action for instantons is calculated using the method of matched background subtraction.

  11. Einstein-Maxwell-Anti-de-Sitter spinning solitons

    NASA Astrophysics Data System (ADS)

    Herdeiro, Carlos; Radu, Eugen

    2016-06-01

    Electrostatics on global Anti-de-Sitter (AdS) spacetime is sharply different from that on global Minkowski spacetime. It admits a multipolar expansion with everywhere regular, finite energy solutions, for every multipole moment except the monopole [1]. A similar statement holds for global AdS magnetostatics. We show that everywhere regular, finite energy, electric plus magnetic fields exist on AdS in three distinct classes: (I) with non-vanishing total angular momentum J; (II) with vanishing J but non-zero angular momentum density, Tφt; (III) with vanishing J and Tφt . Considering backreaction, these configurations remain everywhere smooth and finite energy, and we find, for example, Einstein-Maxwell-AdS solitons that are globally - Type I - or locally (but not globally) - Type II - spinning. This backreaction is considered first perturbatively, using analytical methods and then non-perturbatively, by constructing numerical solutions of the fully non-linear Einstein-Maxwell-AdS system. The variation of the energy and total angular momentum with the boundary data is explicitly exhibited for one example of a spinning soliton.

  12. Einstein-aether theory with a Maxwell field: General formalism

    SciTech Connect

    Balakin, Alexander B.; Lemos, José P.S.

    2014-11-15

    We extend the Einstein-aether theory to include the Maxwell field in a nontrivial manner by taking into account its interaction with the time-like unit vector field characterizing the aether. We also include a generic matter term. We present a model with a Lagrangian that includes cross-terms linear and quadratic in the Maxwell tensor, linear and quadratic in the covariant derivative of the aether velocity four-vector, linear in its second covariant derivative and in the Riemann tensor. We decompose these terms with respect to the irreducible parts of the covariant derivative of the aether velocity, namely, the acceleration four-vector, the shear and vorticity tensors, and the expansion scalar. Furthermore, we discuss the influence of an aether non-uniform motion on the polarization and magnetization of the matter in such an aether environment, as well as on its dielectric and magnetic properties. The total self-consistent system of equations for the electromagnetic and the gravitational fields, and the dynamic equations for the unit vector aether field are obtained. Possible applications of this system are discussed. Based on the principles of effective field theories, we display in an appendix all the terms up to fourth order in derivative operators that can be considered in a Lagrangian that includes the metric, the electromagnetic and the aether fields.

  13. Fundamental Physical Basis for Maxwell-Heaviside Gravitomagnetism

    NASA Astrophysics Data System (ADS)

    Nyambuya, Golden Gadzirayi

    2015-08-01

    Gravitomagnetism is universally and formally recognised in contemporary physics as being the linear first-order approximation of Einstein's field equations emerging from the General Theory of Relativity (GTR). Herein, we argue that, as has been done by others in the past, gravitomagnetism can be viewed as a fully-fledged independent theory of gravitomagnetism that can be divorced from Professor Einstein's GTR. The gravitomagnetic theory whose exposition we give herein is exactly envisioned by Professor Maxwell and Dr. Heaviside. The once speculative Maxwell-Heaviside Gravitomagnetic theory now finds full justification as a fully fledged theory from Professor José Hera's Existence Theorem which states that all that is needed for there to exist the four Max-well-type field equations is that a mass-current conservation law be obeyed. Our contribution in the present work, if any, is that we demonstrate conclusively that like electromagnetism, the gravitomagnetic phenomenon leads to the prediction of gravitomagnetic waves that travel at the speed of light. Further, we argue that for the gravitational phenomenon, apart from the Newtonian gravitational potential, there are four more potentials and these operate concurrently with the Newtonian potential. At the end of it, it is seen that the present work sets the stage for a very interesting investigation of several gravitational anomalies such as the ponderous Pioneer Anomaly, the vexing Flyby Anomalies, the mysterious Anomalous Rotation Curves of Spiral Galaxies and as well, the possibility of the generation of stellar magnetic fields by rotating gravitational masses.

  14. On the entropy variations and the Maxwell relations

    NASA Astrophysics Data System (ADS)

    Zadehgol, Abed; Ashrafizaadeh, Mahmud

    In the present work, it is shown that the Maxwell relations can effectively be used to partially verify the thermodynamic consistency of the entropic lattice kinetic models. As an example, we consider the Constant Speed Kinetic Model (CSKM) which has recently been introduced in [J. Comp. Phys. 274, 803 (2014); Phys Rev. E 91, 063311 (2015)] and show that, for the quasi-equilibrium flows and at low Mach numbers, the entropy variations are proportional to the pressure variations. The entropy variations of the CSKM are logarithmic (given by the Burg entropy) while the pressure variations obey a nonlogarithmic equation of state. The proportionality of these variations, which is in accordance with the Maxwell relations, can be used to partially verify the thermodynamic consistency of the model. A similar treatment of the previously introduced entropic lattice kinetic models (e.g. of the conventional ELBM of [I. V. Karlin, A. Ferrante and H. C. Öttinger, Europhys. Lett. 47, 182 (1999)]), can provide a new ground for comparing the thermodynamic consistency of the existing entropic lattice kinetic models with each other.

  15. Maxwell's demon and the management of ignorance in stochastic thermodynamics

    NASA Astrophysics Data System (ADS)

    Ford, Ian J.

    2016-07-01

    It is nearly 150 years since Maxwell challenged the validity of the second law of thermodynamics by imagining a tiny creature who could sort the molecules of a gas in such a way that would decrease entropy without exerting any work. The demon has been discussed largely using thought experiments, but it has recently become possible to exert control over nanoscale systems, just as Maxwell imagined, and the status of the second law has become a more practical matter, raising the issue of how measurements manage our ignorance in a way that can be exploited. The framework of stochastic thermodynamics extends macroscopic concepts such as heat, work, entropy and irreversibility to small systems and allows us explore the matter. Some arguments against a successful demon imply a second law that can be suspended indefinitely until we dissipate energy in order to remove the records of his operations. In contrast, under stochastic thermodynamics, the demon fails because on average, more work is performed upfront in making a measurement than can be extracted by exploiting the outcome. This requires us to exclude systems and a demon that evolve under what might be termed self-sorting dynamics, and we reflect on the constraints on control that this implies while still working within a thermodynamic framework.

  16. The Covariant Formulation of Maxwell's Equations Expressed in a Form Independent of Specific Units

    ERIC Educational Resources Information Center

    Heras, Jose A.; Baez, G.

    2009-01-01

    The covariant formulation of Maxwell's equations can be expressed in a form independent of the usual systems of units by introducing the constants alpha, beta and gamma into these equations. Maxwell's equations involving these constants are then specialized to the most commonly used systems of units: Gaussian, SI and Heaviside-Lorentz by giving…

  17. General Solutions to Maxwell’s Equations for a Transverse Field.

    DTIC Science & Technology

    1986-05-30

    Maxwell’s equation is a solution to this wave equation, but the converse is not necessarily true. Indeed, by using results from differential geometry...and topology, it is found that smooth, singularity-free transverse solutions to Maxwell’s equation cannot exist if S is a spheroid, a noncircular

  18. 76 FR 56468 - Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New Mexico...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-13

    ... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Museum of Anthropology, University of New Mexico has completed an inventory of human remains, in... itself to be culturally affiliated with the human remains may contact the Maxwell Museum of...

  19. 77 FR 65404 - Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New Mexico...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-26

    ... National Park Service Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New... Anthropology. Repatriation of the human remains to the Indian tribe stated below may occur if no additional.... ADDRESSES: Dr. Heather Edgar, Maxwell Museum of Anthropology, MSC01 1050, University of New...

  20. To Flame With a Wild Life: Florida Scott-Maxwell's Experience of Old Age.

    ERIC Educational Resources Information Center

    Berman, Harry J.

    1986-01-01

    Analyzes an intimate journal, Florida Scott-Maxwell's "The Measure of My Days". Scott-Maxwell's journal contains suggestive ideas about the experience of aging among the old-old, about the theoretical issue of late life individuation, and about successful aging. (Author/ABB)

  1. A Conway-Maxwell-Poisson (CMP) model to address data dispersion on positron emission tomography.

    PubMed

    Santarelli, Maria Filomena; Della Latta, Daniele; Scipioni, Michele; Positano, Vincenzo; Landini, Luigi

    2016-10-01

    Positron emission tomography (PET) in medicine exploits the properties of positron-emitting unstable nuclei. The pairs of γ- rays emitted after annihilation are revealed by coincidence detectors and stored as projections in a sinogram. It is well known that radioactive decay follows a Poisson distribution; however, deviation from Poisson statistics occurs on PET projection data prior to reconstruction due to physical effects, measurement errors, correction of deadtime, scatter, and random coincidences. A model that describes the statistical behavior of measured and corrected PET data can aid in understanding the statistical nature of the data: it is a prerequisite to develop efficient reconstruction and processing methods and to reduce noise. The deviation from Poisson statistics in PET data could be described by the Conway-Maxwell-Poisson (CMP) distribution model, which is characterized by the centring parameter λ and the dispersion parameter ν, the latter quantifying the deviation from a Poisson distribution model. In particular, the parameter ν allows quantifying over-dispersion (ν<1) or under-dispersion (ν>1) of data. A simple and efficient method for λ and ν parameters estimation is introduced and assessed using Monte Carlo simulation for a wide range of activity values. The application of the method to simulated and experimental PET phantom data demonstrated that the CMP distribution parameters could detect deviation from the Poisson distribution both in raw and corrected PET data. It may be usefully implemented in image reconstruction algorithms and quantitative PET data analysis, especially in low counting emission data, as in dynamic PET data, where the method demonstrated the best accuracy.

  2. Maxwell's contrived analogy: An early version of the methodology of modeling

    NASA Astrophysics Data System (ADS)

    Hon, Giora; Goldstein, Bernard R.

    2012-11-01

    The term "analogy" stands for a variety of methodological practices all related in one way or another to the idea of proportionality. We claim that in his first substantial contribution to electromagnetism James Clerk Maxwell developed a methodology of analogy which was completely new at the time or, to borrow John North's expression, Maxwell's methodology was a "newly contrived analogue". In his initial response to Michael Faraday's experimental researches in electromagnetism, Maxwell did not seek an analogy with some physical system in a domain different from electromagnetism as advocated by William Thomson; rather, he constructed an entirely artificial one to suit his needs. Following North, we claim that the modification which Maxwell introduced to the methodology of analogy has not been properly appreciated. In view of our examination of the evidence, we argue that Maxwell gave a new meaning to analogy; in fact, it comes close to modeling in current usage.

  3. Strain Localization in an Oscillating Maxwell Viscoelastic Cylinder.

    PubMed

    Massouros, Panagiotis G; Bayly, Philip V; Genin, Guy M

    2014-01-15

    The transient rotation responses of simple, axisymmetric, viscoelastic structures are of interest for interpretation of experiments designed to characterize materials and closed structures such as the brain using magnetic resonance techniques. Here, we studied the response of a Maxwell viscoelastic cylinder to small, sinusoidal displacement of its outer boundary. The transient strain field can be calculated in closed form using any of several conventional approaches. The solution is surprising: the strain field develops a singularity that appears when the wavefront leaves the center of the cylinder, and persists as the wavefront reflects to the outer boundary and back to the center of the cylinder. The singularity is alternately annihilated and reinitiated upon subsequent departures of the wavefront from the center of the cylinder until it disappears in the limit of steady state oscillations. We present the solution for this strain field, characterize the nature of this singularity, and discuss its potential role in the mechanical response and evolved morphology of the brain.

  4. Deciphering the embedded wave in Saturn's Maxwell ringlet

    NASA Astrophysics Data System (ADS)

    French, Richard G.; Nicholson, Philip D.; Hedman, Mathew M.; Hahn, Joseph M.; McGhee-French, Colleen A.; Colwell, Joshua E.; Marouf, Essam A.; Rappaport, Nicole J.

    2016-11-01

    The eccentric Maxwell ringlet in Saturn's C ring is home to a prominent wavelike structure that varies strongly and systematically with true anomaly, as revealed by nearly a decade of high-SNR Cassini occultation observations. Using a simple linear "accordion" model to compensate for the compression and expansion of the ringlet and the wave, we derive a mean optical depth profile for the ringlet and a set of rescaled, background-subtracted radial wave profiles. We use wavelet analysis to identify the wave as a 2-armed trailing spiral, consistent with a density wave driven by an m = 2 outer Lindblad resonance (OLR), with a pattern speed Ωp = 1769.17° d-1 and a corresponding resonance radius ares = 87530.0 km. Estimates of the surface mass density of the Maxwell ringlet range from a mean value of 11g cm-2 derived from the self-gravity model to 5 - 12gcm-2 , as inferred from the wave's phase profile and a theoretical dispersion relation. The corresponding opacity is about 0.12 cm2 g-1, comparable to several plateaus in the outer C ring (Hedman, M.N., Nicholson, P.D. [2014]. Mont. Not. Roy. Astron. Soc. 444, 1369-1388). A linear density wave model using the derived wave phase profile nicely matches the wave's amplitude, wavelength, and phase in most of our observations, confirming the accuracy of the pattern speed and demonstrating the wave's coherence over a period of 8 years. However, the linear model fails to reproduce the narrow, spike-like structures that are prominent in the observed optical depth profiles. Using a symplectic N-body streamline-based dynamical code (Hahn, J.M., Spitale, J.N. [2013]. Astrophys. J. 772, 122), we simulate analogs of the Maxwell ringlet, modeled as an eccentric ringlet with an embedded wave driven by a fictitious satellite with an OLR located within the ring. The simulations reproduce many of the features of the actual observations, including strongly asymmetric peaks and troughs in the inward-propagating density wave. We argue that

  5. Structures of general relativity in dilaton-Maxwell electrodynamics

    NASA Astrophysics Data System (ADS)

    Kechkin, O. V.; Mosharev, P. A.

    2016-08-01

    It is shown that electro (magneto) static sector of Maxwell’s electrodynamics coupled to the dilaton field in a string theory form possesses the symmetry group of the stationary General Relativity in vacuum. Performing the Ernst formalism, we develope a technique for generation of exact solutions in this modified electrodynamics on the base of the normalized Ehlers symmetry transformation. In the electrostatic case, we construct and study a general class of spherically symmetric solutions that describes a pointlike source of the Coulomb type. It is demonstrated that this source is characterized by finite and singularity-free interaction at short distances. Also it is established that the total electrostatic energy of this source is finite and inversely proportional to the dilaton-Maxwell coupling constant.

  6. A Generalization of the Einstein-Maxwell Equations

    NASA Astrophysics Data System (ADS)

    Cotton, Fredrick

    2016-03-01

    The proposed modifications of the Einstein-Maxwell equations include: (1) the addition of a scalar term to the electromagnetic side of the equation rather than to the gravitational side, (2) the introduction of a 4-dimensional, nonlinear electromagnetic constitutive tensor and (3) the addition of curvature terms arising from the non-metric components of a general symmetric connection. The scalar term is defined by the condition that a spherically symmetric particle be force-free and mathematically well-behaved everywhere. The constitutive tensor introduces two auxiliary fields which describe the particle structure. The additional curvature terms couple both to particle solutions and to electromagnetic and gravitational wave solutions. http://sites.google.com/site/fwcotton/em-30.pdf

  7. On the locally rotationally symmetric Einstein-Maxwell perfect fluid

    NASA Astrophysics Data System (ADS)

    Pugliese, D.; Valiente Kroon, J. A.

    2016-06-01

    We examine the stability of Einstein-Maxwell perfect fluid configurations with a privileged radial direction by means of a 1+1+2-tetrad formalism. We use this formalism to cast in a quasilinear symmetric hyperbolic form the equations describing the evolution of the system. This hyperbolic reduction is used to discuss the stability of linear perturbations in some special cases. By restricting the analysis to isotropic fluid configurations, we assume a constant electrical conductivity coefficient for the fluid. As a result of this analysis we provide a complete classification and characterization of various stable and unstable configurations. We find, in particular, that in many cases the stability conditions are strongly determined by the constitutive equations and the electric conductivity. A threshold for the emergence of the instability appears in both contracting and expanding systems.

  8. Fourier analysis of numerical algorithms for the Maxwell equations

    NASA Technical Reports Server (NTRS)

    Liu, Yen

    1993-01-01

    The Fourier method is used to analyze the dispersive, dissipative, and isotropy errors of various spatial and time discretizations applied to the Maxwell equations on multi-dimensional grids. Both Cartesian grids and non-Cartesian grids based on hexagons and tetradecahedra are studied and compared. The numerical errors are quantitatively determined in terms of phase speed, wave number, propagation direction, gridspacings, and CFL number. The study shows that centered schemes are more efficient than upwind schemes. The non-Cartesian grids yield superior isotropy and higher accuracy than the Cartesian ones. For the centered schemes, the staggered grids produce less errors than the unstaggered ones. A new unstaggered scheme which has all the best properties is introduced. The study also demonstrates that a proper choice of time discretization can reduce the overall numerical errors due to the spatial discretization.

  9. Tidal dissipation in heterogeneous bodies: Maxwell vs Andrade rheology

    NASA Astrophysics Data System (ADS)

    Behounkova, M.; Cadek, O.

    2014-04-01

    The tremendous volcanism on Jupiter's moon Io as well as the huge activity at the south pole of Saturn's moon Enceladus show that tidal dissipation is a very strong source of energy for some bodies in the Solar System. Outside the Solar System, tidal heating in short-period exoplanets may cause Io-like volcanism, large-scale melting and even thermal runaways [1-4]. Here we further develop the method to compute tidal heating in heterogeneous bodies [5]. Especially, we concentrate on the Andrade rheology implementation. We study the impact of the improved model on bodies with large lateral viscosity variation such as Enceladus and tidally locked exoEarth with a large surface temperature contrast due to uneven insolation [6]. We discuss the influence of empirical parameters describing the Andrade rheology and compare the tidal heating and tidal stress obtained for the Andrade rheology with frequently used Maxwell models for different forcing frequencies.

  10. Maxwell's demons everywhere: evolving design as the arrow of time.

    PubMed

    Bejan, Adrian

    2014-02-10

    Science holds that the arrow of time in nature is imprinted on one-way (irreversible) phenomena, and is accounted for by the second law of thermodynamics. Here I show that the arrow of time is painted much more visibly on another self-standing phenomenon: the occurrence and change (evolution in time) of flow organization throughout nature, animate and inanimate. This other time arrow has been present in science but not recognized as such since the birth of thermodynamics. It is Maxwell's demon. Translated in macroscopic terms, this is the physics of the phenomenon of design, which is the universal natural tendency of flow systems to evolve into configurations that provide progressively greater access over time, and is summarized as the constructal law of design and evolution in nature. Knowledge is the ability to effect design changes that facilitate human flows on the landscape. Knowledge too flows.

  11. Einstein-Maxwell-dilaton theories with a Liouville potential

    SciTech Connect

    Charmousis, Christos; Gouteraux, Blaise; Soda, Jiro

    2009-07-15

    We find and analyze solutions of Einstein's equations in arbitrary dimensions and in the presence of a scalar field with a Liouville potential coupled to a Maxwell field. We consider spacetimes of cylindrical symmetry or again subspaces of dimension d-2 with constant curvature and analyze in detail the field equations and manifest their symmetries. The field equations of the full system are shown to reduce to a single or couple of ordinary differential equations, which can be used to solve analytically or numerically the theory for the symmetry at hand. Further solutions can also be generated by a solution-generating technique akin to the electromagnetic duality in the absence of a cosmological constant. We then find and analyze explicit solutions including black holes and gravitating solitons for the case of four-dimensional relativity and the higher-dimensional oxidized five-dimensional spacetime. The general solution is obtained for a certain relation between couplings in the case of cylindrical symmetry.

  12. Implicit a posteriori error estimates for the Maxwell equations

    NASA Astrophysics Data System (ADS)

    Izsak, Ferenc; Harutyunyan, Davit; van der Vegt, Jaap J. W.

    2008-09-01

    An implicit a posteriori error estimation technique is presented and analyzed for the numerical solution of the time-harmonic Maxwell equations using Nedelec edge elements. For this purpose we define a weak formulation for the error on each element and provide an efficient and accurate numerical solution technique to solve the error equations locally. We investigate the well-posedness of the error equations and also consider the related eigenvalue problem for cubic elements. Numerical results for both smooth and non-smooth problems, including a problem with reentrant corners, show that an accurate prediction is obtained for the local error, and in particular the error distribution, which provides essential information to control an adaptation process. The error estimation technique is also compared with existing methods and provides significantly sharper estimates for a number of reported test cases.

  13. How can an autonomous quantum Maxwell demon harness correlated information?

    NASA Astrophysics Data System (ADS)

    Chapman, Adrian; Miyake, Akimasa; CQuIC Thermodynamics Team

    We study an autonomous quantum system, which exhibits refrigeration under an information-work tradeoff like a Maxwell demon. The system becomes correlated as a single ``demon'' qubit interacts sequentially with memory qubits while in contact with two heat reservoirs of different temperatures. Using strong subadditivity of the von Neumann entropy, we derive a global Clausius inequality to show thermodynamical advantages from access to correlated information. It is demonstrated, in a matrix product density operator formalism, that our demon can simultaneously realize refrigeration against a thermal gradient and erasure of information from its memory, which is impossible without correlations. The phenomenon can be even enhanced by the presence of quantum coherence. The work was supported in part by National Science Foundation Grants PHY-1212445 and PHY-1521016.

  14. Quantum entanglement of locally excited states in Maxwell theory

    NASA Astrophysics Data System (ADS)

    Nozaki, Masahiro; Watamura, Naoki

    2016-12-01

    In 4 dimensional Maxwell gauge theory, we study the changes of (Rényi) entanglement entropy which are defined by subtracting the entropy for the ground state from the one for the locally excited states, generated by acting with gauge invariant local operators on the state. The changes for the operators which we consider in this paper reflect the electric-magnetic duality. The late-time value of changes can be interpreted in terms of electromagnetic quasi-particles. When the operator constructed of both electric and magnetic fields acts on the ground state, it shows that the operator acts on the late-time structure of quantum entanglement differently from free scalar fields.

  15. Maxwell's demon in biochemical signal transduction with feedback loop

    NASA Astrophysics Data System (ADS)

    Ito, Sosuke; Sagawa, Takahiro

    2015-06-01

    Signal transduction in living cells is vital to maintain life itself, where information transfer in noisy environment plays a significant role. In a rather different context, the recent intensive research on `Maxwell's demon'--a feedback controller that utilizes information of individual molecules--have led to a unified theory of information and thermodynamics. Here we combine these two streams of research, and show that the second law of thermodynamics with information reveals the fundamental limit of the robustness of signal transduction against environmental fluctuations. Especially, we find that the degree of robustness is quantitatively characterized by an informational quantity called transfer entropy. Our information-thermodynamic approach is applicable to biological communication inside cells, in which there is no explicit channel coding in contrast to artificial communication. Our result could open up a novel biophysical approach to understand information processing in living systems on the basis of the fundamental information-thermodynamics link.

  16. Maxwell's Demons Everywhere: Evolving Design as the Arrow of Time

    PubMed Central

    Bejan, Adrian

    2014-01-01

    Science holds that the arrow of time in nature is imprinted on one-way (irreversible) phenomena, and is accounted for by the second law of thermodynamics. Here I show that the arrow of time is painted much more visibly on another self-standing phenomenon: the occurrence and change (evolution in time) of flow organization throughout nature, animate and inanimate. This other time arrow has been present in science but not recognized as such since the birth of thermodynamics. It is Maxwell's demon. Translated in macroscopic terms, this is the physics of the phenomenon of design, which is the universal natural tendency of flow systems to evolve into configurations that provide progressively greater access over time, and is summarized as the constructal law of design and evolution in nature. Knowledge is the ability to effect design changes that facilitate human flows on the landscape. Knowledge too flows. PMID:24510201

  17. Using Maxwell's Equations in the late 1800s

    NASA Astrophysics Data System (ADS)

    Buchwald, Jed

    2012-02-01

    Between the publication of Maxwell's Treatise on Electricity and Magnetism in 1873 and the early 1900s his field equations were not considered to be fundamental by many Cambridge-trained physicists Instead, they were thought to derive from Hamilton's principle given an appropriate energy expression. Such an expression usually assigned a velocity or a position function to field quantities, though this was not invariably done. Precisely because the Hamiltonian, and not the derivative field equations, was taken to be basic, new effects could be generated by adding terms to the energy expression. This was how the Faraday and Kerr magneto-optic effects were handled. The program however never did generate a method for incorporating dissipative phenomena, as Oliver Heaviside (who disliked the use of Hamilton's principle) demonstrated. The procedure was in the end decisively abandoned when J. G. Leathem, a student of Joseph Larmor a Cambridge, demonstrated that it could not handle a particularly subtle magneto-optic process.

  18. Development and Application of Compatible Discretizations of Maxwell's Equations

    SciTech Connect

    White, D; Koning, J; Rieben, R

    2005-05-27

    We present the development and application of compatible finite element discretizations of electromagnetics problems derived from the time dependent, full wave Maxwell equations. We review the H(curl)-conforming finite element method, using the concepts and notations of differential forms as a theoretical framework. We chose this approach because it can handle complex geometries, it is free of spurious modes, it is numerically stable without the need for filtering or artificial diffusion, it correctly models the discontinuity of fields across material boundaries, and it can be very high order. Higher-order H(curl) and H(div) conforming basis functions are not unique and we have designed an extensible C++ framework that supports a variety of specific instantiations of these such as standard interpolatory bases, spectral bases, hierarchical bases, and semi-orthogonal bases. Virtually any electromagnetics problem that can be cast in the language of differential forms can be solved using our framework. For time dependent problems a method-of-lines scheme is used where the Galerkin method reduces the PDE to a semi-discrete system of ODE's, which are then integrated in time using finite difference methods. For time integration of wave equations we employ the unconditionally stable implicit Newmark-Beta method, as well as the high order energy conserving explicit Maxwell Symplectic method; for diffusion equations, we employ a generalized Crank-Nicholson method. We conclude with computational examples from resonant cavity problems, time-dependent wave propagation problems, and transient eddy current problems, all obtained using the authors massively parallel computational electromagnetics code EMSolve.

  19. 78 FR 45963 - Notice of Intent to Repatriate Cultural Item: Maxwell Museum of Anthropology, University of New...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-30

    ... National Park Service Notice of Intent to Repatriate Cultural Item: Maxwell Museum of Anthropology...: The Maxwell Museum of Anthropology, in consultation with the appropriate Indian tribes or Native... the Maxwell Museum of Anthropology. If no additional claimants come forward, transfer of control...

  20. 77 FR 19697 - Notice of Intent to Repatriate Cultural Items: Maxwell Museum of Anthropology, University of New...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-02

    ... National Park Service Notice of Intent to Repatriate Cultural Items: Maxwell Museum of Anthropology...: The Maxwell Museum of Anthropology, in consultation with the appropriate Indian tribes, has determined... Maxwell Museum of Anthropology. DATES: Representatives of any Indian tribe that believes it has a...

  1. Lifting of the Vlasov-Maxwell Bracket by Lie-transform Method

    NASA Astrophysics Data System (ADS)

    Brizard, A. J.; Morrison, P. J.; Burby, J. W.

    2016-10-01

    The Vlasov-Maxwell equations possess a Hamiltonian structure expressed in terms of a Hamiltonian functional and a functional bracket. The transformation (``lift'') of the Vlasov-Maxwell bracket induced by the dynamical reduction of single-particle dynamics is investigated when the reduction is carried out by Lie-transform perturbation methods. The ultimate goal of this work is to derive explicit Hamiltonian formulations for the guiding-center and gyrokinetic Vlasov-Maxwell equations that have important applications in our understanding of turbulent magnetized plasmas. In particular, we investigate how the Hamiltonian properties of the reduced Vlasov-Maxwell bracket survive (1) the closure problem: the process of truncation of the guiding-center Vlasov-Maxwell bracket at a finite order in ɛ (so far expressions have been derived at all orders in ɛ) and (2) the averaging problem: the process by which which the gyroangle is eliminated from the guiding-center Vlasov-Maxwell bracket (since guiding-center Vlasov-Maxwell equations do not involve the fast gyromotion time scale). Work supported by Grants from US DoE.

  2. Parasitic extraction and magnetic analysis for transformers, inductors and igbt bridge busbar with maxwell 2d and maxwell 3d simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Ning

    This thesis presents the parasitic extraction and magnetic analysis for transformers, inductors, and IGBT bridge busbars with Maxwell 2D and Maxwell 3D simulation. In the first chapter, the magnetic field of a transformer in Maxwell 2D is analyzed. The parasitic capacitance between each winding of the transformer are extracted by Maxwell 2D. According to the actual dimensions, the parasitic capacitances are calculated. The results are verified by comparing with the measurement results from 4395A impedance analyzer. In the second chapter, two CM inductors are simulated in Maxwell 3D. One is the conventional winding inductor, the other one is the proposed one. The magnetic field distributions of different winding directions are analyzed. The analysis is verified by the simulation result. The last chapter introduces a technique to analyze, extract, and measure the parasitic inductance of planar busbars. With this technique, the relationship between self-inductance and mutual-inductance is analyzed. Secondly, a total inductance is calculated based on the developed technique. Thirdly, the current paths and the inductance on a planar busbar are investigated with DC-link capacitors. Furthermore, the analysis of the inductance is addressed. Ansys Q3D simulation and analysis are presented. Finally, the experimental verification is shown by the S-parameter measurement.

  3. Characterizing the performance of the Conway-Maxwell Poisson generalized linear model.

    PubMed

    Francis, Royce A; Geedipally, Srinivas Reddy; Guikema, Seth D; Dhavala, Soma Sekhar; Lord, Dominique; LaRocca, Sarah

    2012-01-01

    Count data are pervasive in many areas of risk analysis; deaths, adverse health outcomes, infrastructure system failures, and traffic accidents are all recorded as count events, for example. Risk analysts often wish to estimate the probability distribution for the number of discrete events as part of doing a risk assessment. Traditional count data regression models of the type often used in risk assessment for this problem suffer from limitations due to the assumed variance structure. A more flexible model based on the Conway-Maxwell Poisson (COM-Poisson) distribution was recently proposed, a model that has the potential to overcome the limitations of the traditional model. However, the statistical performance of this new model has not yet been fully characterized. This article assesses the performance of a maximum likelihood estimation method for fitting the COM-Poisson generalized linear model (GLM). The objectives of this article are to (1) characterize the parameter estimation accuracy of the MLE implementation of the COM-Poisson GLM, and (2) estimate the prediction accuracy of the COM-Poisson GLM using simulated data sets. The results of the study indicate that the COM-Poisson GLM is flexible enough to model under-, equi-, and overdispersed data sets with different sample mean values. The results also show that the COM-Poisson GLM yields accurate parameter estimates. The COM-Poisson GLM provides a promising and flexible approach for performing count data regression.

  4. Treatment of painful pediatric flatfoot with Maxwell-Brancheau subtalar arthroereisis implant a retrospective radiographic review.

    PubMed

    Scharer, Brandon M; Black, Brian E; Sockrider, Nathan

    2010-04-01

    The purposes of this study were to evaluate the outcome of pediatric patients who have undergone Maxwell-Brancheau arthroereisis (MBA) subtalar implants for the treatment of painful pediatric flatfoot deformities. In a retrospective study, 39 patients (68 feet) were evaluated clinically and radiographically. The mean age of the patients was 12 years (range, 6-16 years). The mean period of follow-up was 24 months (range, 6-61 months). Statistical evaluation was performed on all radiographic measurements. Additional surgical procedures (gastrocnemius recession, Achilles tendon lengthening, Kidner posterior tibial tendon advancement) were performed in 22 of 68 feet. There were 10 (15%) complications, which consisted of 10 reoperations in 10 feet. Implants were exchanged in 9 feet because of implant migration, undercorrection, and overcorrection. There was 1 reoperation (in 1 foot) for implant removal because of persistent sinus tarsi pain. Radiographic evaluation demonstrated an improvement of all parameters determined. The parameters that were evaluated include talonavicular joint coverage, as well as lateral and anterior-posterior talocalcaneal angles. There were significant changes noted in pre- and postoperative measurements (P < .001). The MBA implant is effective for the correction of painful, flexible flatfoot deformity in children in short-term follow-up. However, this is a multiplanar deformity, and additional procedures may be needed in addition to the MBA.

  5. Eaters of the lotus: Landauer's principle and the return of Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Norton, John D.

    Landauer's principle is the loosely formulated notion that the erasure of n bits of information must always incur a cost of k ln n in thermodynamic entropy. It can be formulated as a precise result in statistical mechanics, but for a restricted class of erasure processes that use a thermodynamically irreversible phase space expansion, which is the real origin of the law's entropy cost and whose necessity has not been demonstrated. General arguments that purport to establish the unconditional validity of the law (erasure maps many physical states to one; erasure compresses the phase space) fail. They turn out to depend on the illicit formation of a canonical ensemble from memory devices holding random data. To exorcise Maxwell's demon one must show that all candidate devices-the ordinary and the extraordinary-must fail to reverse the second law of thermodynamics. The theorizing surrounding Landauer's principle is too fragile and too tied to a few specific examples to support such general exorcism. Charles Bennett's recent extension of Landauer's principle to the merging of computational paths fails for the same reasons as trouble the original principle.

  6. James Clerk Maxwell, a precursor of system identification and control science

    NASA Astrophysics Data System (ADS)

    Bittanti, Sergio

    2015-12-01

    One hundred and fifty years ago James Clerk Maxwell published his celebrated paper 'Dynamical theory of electromagnetic field', where the interaction between electricity and magnetism eventually found an explanation. However, Maxwell was also a precursor of model identification and control ideas. Indeed, with the paper 'On Governors' of 1869, he introduced the concept of feedback control system; and moreover, with his essay on Saturn's rings of 1856 he set the basic principle of system identification. This paper is a tutorial exposition having the aim to enlighten these latter aspects of Maxwell's work.

  7. Computational analysis of magnetohydrodynamic Casson and Maxwell flows over a stretching sheet with cross diffusion

    NASA Astrophysics Data System (ADS)

    Kumaran, G.; Sandeep, N.; Ali, M. E.

    This paper reports the magnetohydrodynamic chemically reacting Casson and Maxwell fluids past a stretching sheet with cross diffusion, non-uniform heat source/sink, thermophoresis and Brownian motion effects. Numerical results are obtained by employing the R-K based shooting method. Effects of pertinent parameters on flow, thermal and concentration fields are discussed with graphical illustrations. We presented the tabular results to discuss the nature of the skin friction coefficient, reduced Nusselt and Sherwood numbers. Dual nature is observed in the solution of Casson and Maxwell fluids. It is also observed a significant increase in heat and mass transfer rate of Maxwell fluid when compared with the Casson fluid.

  8. Time domain solutions of Maxwell's equations using a finite-volume formulation

    SciTech Connect

    Noack, R.W.

    1991-01-01

    A new method for solving Maxwell's equations in the time domain was developed. The method approximates the integral form of the time-dependent Maxwell's equations using a finite-volume formulation. The method utilizes a staggered mesh and requires boundary conditions on the electric field or the magnetic field but not both. Predictions from the present method were compared to exact solutions for a full three-dimensional calculation of a sphere and experimental measurements for a generic missile body. These comparisons show that the method is capable of accurately solving the time-dependent Maxwell's equations and yields accurate predictions of the radar cross section for arbitrary geometries.

  9. ON THE ROLE OF INVOLUTIONS IN THE DISCONTINUOUS GALERKIN DISCRETIZATION OF MAXWELL AND MAGNETOHYDRODYNAMIC SYSTEMS

    NASA Technical Reports Server (NTRS)

    Barth, Timothy

    2005-01-01

    The role of involutions in energy stability of the discontinuous Galerkin (DG) discretization of Maxwell and magnetohydrodynamic (MHD) systems is examined. Important differences are identified in the symmetrization of the Maxwell and MHD systems that impact the construction of energy stable discretizations using the DG method. Specifically, general sufficient conditions to be imposed on the DG numerical flux and approximation space are given so that energy stability is retained These sufficient conditions reveal the favorable energy consequence of imposing continuity in the normal component of the magnetic induction field at interelement boundaries for MHD discretizations. Counterintuitively, this condition is not required for stability of Maxwell discretizations using the discontinuous Galerkin method.

  10. Gravitational spreading of Danu, Freyja and Maxwell Montes, Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, Suzanne E.; Solomon, Sean C.

    1991-01-01

    The potential energy of elevated terrain tends to drive the collapse of the topography. This process of gravitational spreading is likely to be more important on Venus than on Earth because the higher surface temperature weakens the crust. The highest topography on Venus is Ishtar Terra. The high plateau of Lakshmi Planum has an average elevation of 3 km above mean planetary radius, and is surrounded by mountain belts. Freyja, Danu, and Maxwell Montes rise, on average, an additional 3, 0.5, and 5 km above the plateau, respectively. Recent high resolution Magellan radar images of this area, east of approx. 330 deg E, reveal widespread evidence for gravity spreading. Some observational evidence is described for gravity spreading and the implications are discussed in terms of simple mechanical models. Several simple models predict that gravity spreading should be an important process on Venus. One difficulty in using remote observations to infer interior properties is that the observed features may not have formed in response to stresses which are still active. Several causes of surface topography are briefly examined.

  11. A New Observing Tool for the James Clerk Maxwell Telescope

    NASA Astrophysics Data System (ADS)

    Folger, Martin; Bridger, Alan; Dent, Bill; Kelly, Dennis; Adamson, Andy; Economou, Frossie; Hirst, Paul; Jenness, Tim

    A new Observing Tool (OT) has been developed at the UK Astronomy Technology Centre, Edinburgh, UK and the Joint Astronomy Centre, Hilo, Hawaii, USA. It is based on the Gemini Observing Tool and provides the first graphical observation preparation tool for the James Clerk Maxwell Telescope (JCMT) as well as being the first use of the OT for a non-optical/IR telescope. The OT allows the observer to assemble high level Science Programs using graphical representations of observation components such as instrument, target, and filter. This is later translated into low level control sequences for telescope and instruments. The new OT is designed to work on multiple telescopes: currently the UK Infrared Telescope (UKIRT) and JCMT. Object-oriented design makes the inclusion of telescope and instrument specific packages easy. The OT is written in Java using GUI packages such as Swing and JSky. A new component for the JCMT OT is the graphical Frequency Editor for Heterodyne instruments. It can be used to specify parameters such as frequencies, bandwidths, and sidebands of multiple subsystems, while graphically displaying the front-end frequency, emission lines and atmospheric transmission. In addition, Flexible Scheduling support has been added to the OT. The observer can define scheduling constraints by arranging observations graphically. Science Programs can be saved as XML or sent directly from the OT to a database (via SOAP).

  12. From Maxwell's Equations to Polarimetric SAR Images: A Simulation Approach.

    PubMed

    Sant'Anna, Sidnei J S; Da S Lacava, J C; Fernandes, David

    2008-11-19

    A new electromagnetic approach for the simulation of polarimetric SAR images is proposed. It starts from Maxwell's equations, employs the spectral domain full-wave technique, the moment method, and the stationary phase method to compute the far electromagnetic fields scattered by multilayer structures. A multilayer structure is located at each selected position of a regular rectangular grid of coordinates, which defines the scene area under imaging. The grid is determined taking into account the elementary scatter size and SAR operational parameters, such as spatial resolution, pixel spacing, look angle and platform altitude. A two-dimensional separable "sinc" function to represent the SAR spread point function is also considered. Multifrequency sets of single-look polarimetric SAR images are generated, in L-, C- and X-bands and the images are evaluated using several measurements commonly employed in SAR data analysis. The evaluation shows that the proposed simulation process is working properly, since the obtained results are in accordance with those presented in the literature. Therefore, this new approach becomes suitable for carrying out theoretical and practical studies using polarimetric SAR images.

  13. From Maxwell's Equations to Polarimetric SAR Images: A Simulation Approach

    PubMed Central

    Sant'Anna, Sidnei J. S.; da S. Lacava, J. C.; Fernandes, David

    2008-01-01

    A new electromagnetic approach for the simulation of polarimetric SAR images is proposed. It starts from Maxwell's equations, employs the spectral domain full-wave technique, the moment method, and the stationary phase method to compute the far electromagnetic fields scattered by multilayer structures. A multilayer structure is located at each selected position of a regular rectangular grid of coordinates, which defines the scene area under imaging. The grid is determined taking into account the elementary scatter size and SAR operational parameters, such as spatial resolution, pixel spacing, look angle and platform altitude. A two-dimensional separable “sinc” function to represent the SAR spread point function is also considered. Multifrequency sets of single-look polarimetric SAR images are generated, in L-, C- and X-bands and the images are evaluated using several measurements commonly employed in SAR data analysis. The evaluation shows that the proposed simulation process is working properly, since the obtained results are in accordance with those presented in the literature. Therefore, this new approach becomes suitable for carrying out theoretical and practical studies using polarimetric SAR images. PMID:27873935

  14. Relativistic plasma expansion with Maxwell-Ju¨ttner distribution

    NASA Astrophysics Data System (ADS)

    Huang, Yongsheng; Wang, Naiyan; Tang, Xiuzhang; Shi, Yijin

    2013-11-01

    A self-similar analytical solution is proposed to describe the relativistic ion acceleration with the local Maxwell-Ju¨ttner relativistic distribution electrons. It is an alternative to the existing static model [M. Passoni and M. Lontano, Phys. Rev. Lett. 101, 115001 (2008)], which exploits a limited solution for the acceleration potential. With our model, the potential is finite naturally and has an upper limitation proportional to the square root of the electron temperature. The divergent potential in the non-relativistic case is the linear items of the Taylor expansion of that obtained relativistic one here. The energy distribution of ions and the dependence of the ion momentum on the acceleration time are obtained analytically. Maximum ion energy has an upper limitation decided by the finite potential difference. In the ultra-relativistic region, the ion energy at the ion front is proportional to t4/5 and the energy of the ions behind the ion front is proportional to t2/3 since the field there is shielded by the ions beyond them and the field at the ion front is the most intense.

  15. Trading coherence and entropy by a quantum Maxwell demon

    NASA Astrophysics Data System (ADS)

    Lebedev, A. V.; Oehri, D.; Lesovik, G. B.; Blatter, G.

    2016-11-01

    The second law of thermodynamics states that the entropy of a closed system is nondecreasing. Discussing the second law in the quantum world poses different challenges and provides different opportunities, involving fundamental quantum-information-theoretic questions and interesting quantum-engineered devices. In quantum mechanics, systems with an evolution described by a so-called unital quantum channel evolve with a nondecreasing entropy. Here, we seek the opposite, a system described by a nonunital and, furthermore, energy-conserving channel that describes a system whose entropy decreases with time. We propose a setup involving a mesoscopic four-lead scatterer augmented by a microenvironment in the form of a spin that realizes this goal. Within this nonunital and energy-conserving quantum channel, the microenvironment acts with two noncommuting operations on the system in an autonomous way. We find that the process corresponds to a partial exchange or swap between the system and environment quantum states, with the system's entropy decreasing if the environment's state is more pure. This entropy-decreasing process is naturally expressed through the action of a quantum Maxwell demon and we propose a quantum-thermodynamic engine with four qubits that extracts work from a single heat reservoir when provided with a reservoir of pure qubits. The special feature of this engine, which derives from the energy conservation in the nonunital quantum channel, is its separation into two cycles, a working cycle and an entropy cycle, allowing us to run this engine with no local waste heat.

  16. Notes on Landauer's principle, reversible computation, and Maxwell's Demon

    NASA Astrophysics Data System (ADS)

    Bennett, Charles H.

    Landauer's principle, often regarded as the basic principle of the thermodynamics of information processing, holds that any logically irreversible manipulation of information, such as the erasure of a bit or the merging of two computation paths, must be accompanied by a corresponding entropy increase in non-information-bearing degrees of freedom of the information-processing apparatus or its environment. Conversely, it is generally accepted that any logically reversible transformation of information can in principle be accomplished by an appropriate physical mechanism operating in a thermodynamically reversible fashion. These notions have sometimes been criticized either as being false, or as being trivial and obvious, and therefore unhelpful for purposes such as explaining why Maxwell's Demon cannot violate the second law of thermodynamics. Here I attempt to refute some of the arguments against Landauer's principle, while arguing that although in a sense it is indeed a straightforward consequence or restatement of the Second Law, it still has considerable pedagogic and explanatory power, especially in the context of other influential ideas in nineteenth and twentieth century physics. Similar arguments have been given by Jeffrey Bub (2002).

  17. Maxwell's equations-based dynamic laser-tissue interaction model.

    PubMed

    Ahmed, Elharith M; Barrera, Frederick J; Early, Edward A; Denton, Michael L; Clark, C D; Sardar, Dhiraj K

    2013-12-01

    Since its invention in the early 1960s, the laser has been used as a tool for surgical, therapeutic, and diagnostic purposes. To achieve maximum effectiveness with the greatest margin of safety it is important to understand the mechanisms of light propagation through tissue and how that light affects living cells. Lasers with novel output characteristics for medical and military applications are too often implemented prior to proper evaluation with respect to tissue optical properties and human safety. Therefore, advances in computational models that describe light propagation and the cellular responses to laser exposure, without the use of animal models, are of considerable interest. Here, a physics-based laser-tissue interaction model was developed to predict the dynamic changes in the spatial and temporal temperature rise during laser exposure to biological tissues. Unlike conventional models, the new approach is grounded on the rigorous electromagnetic theory that accounts for wave interference, polarization, and nonlinearity in propagation using a Maxwell's equations-based technique.

  18. Two versions of Maxwell's equations and the nature of light

    NASA Astrophysics Data System (ADS)

    Gill, Tepper L.; Zachary, Woodford W.

    2009-08-01

    In this paper, we show that there are actually two versions of Maxwell's equations. The new version is mathematically, but not physically, equivalent to the conventional form. It was missed because of an attempt to give a mathematical fix for a basic physical problem. This second formulation fixes the clock of the field source for all inertial observers. However now, the (natural definition of the effective) speed of light is no longer an invariant for all observers, but depends on the motion of the source. This approach allows us to account for radiation reaction without the Lorentz-Dirac equation, self-energy (divergence), advanced potentials or any assumptions about the structure of the source. This version has a new invariance group which, in general, is a nonlinear and nonlocal representation of the Lorentz group, and provides a natural (and unique) definition of simultaneity for all observers. We briefly review the corresponding particle mechanics. The purpose is to show that there is a (unique) clock for any closed system of physical bodies. This clock provides a unique definition of simultaneity for all events associated with the system. We then discuss our view of the photon within this theory.

  19. Maxwell stress induced optical torque upon gold prolate nanospheroid

    NASA Astrophysics Data System (ADS)

    Liaw, Jiunn-Woei; Chen, Ying-Syuan; Kuo, Mao-Kuen

    2016-03-01

    This study theoretically analyzes the surface traction on an elongated Au prolate nanospheroid to examine the resultant optical torque exerted by an optical tweezers. The multiple multipole method is applied to evaluate quantitatively the electromagnetic field induced by a linearly polarized plane wave illuminating a nanospheroid, then obtaining the surface traction in terms of Maxwell stress tensor. The optical torque is calculated by the surface integral of the cross product of position vector and traction over the nanospheroid's surface. Our results show that two pairs of positive and negative traction zones at the two apexes of the nanospheroid play a critical role. Furthermore, the resultant optical torque is wavelength-dependent. If the wavelength is shorter than the longitudinal surface plasmon resonance (LSPR) of the nanospheroid, the optical torque rotates the long axis of nanospheroid perpendicular to the polarization direction of the incident wave. In contrast, if the wavelength is longer than the LSPR the long axis is pushed parallel to the polarization direction. The turning point with a null torque, between the perpendicular and parallel modes, is at the LSPR. The optical performance of Au nanospheroid is equivalent to that of Au NR with the same volume and aspect ratio, but the LSPR of Au NR is little red-shifted from that of an equivalent prolate spheroid.

  20. Chaotic Dynamics of Falling Disks: from Maxwell to Bar Tricks.

    NASA Astrophysics Data System (ADS)

    Field, Stuart

    1998-03-01

    Understanding the motion of flat objects falling in a viscous medium dates back to at least Newton and Maxwell, and is relevant to problems in meteorology, sedimentology, aerospace and chemical engineering, and bar wagering strategies. Recent theoretical studies have emphasized the role played by deterministic chaos. Here we report(S. B. Field, M. Klaus, M. G. Moore, and F. Nori, Nature 388), 252 (1997) experimental observations and theoretical analysis of the dynamics of disks falling in water/glycerol mixtures. We find four distinct types of motion, and map out a ``phase diagram'' in the appropriate variables. The apparently complex behavior of the disks can be reduced to a series of one-dimensional maps which display a discontinuity at the crossover from periodic and chaotic motion. This discontinuity leads to an unusual intermittency transition between the two behaviors, which has not previously been observed experimentally in any system.

  1. 5D Einstein-Maxwell solitons and concentric rotating dipole black rings

    SciTech Connect

    Yazadjiev, Stoytcho S.

    2008-09-15

    We discuss the application of the solitonic techniques to the 5D Einstein-Maxwell gravity. As an illustration we construct a new exact solution describing two concentric rotating dipole black rings. The properties of the solution are investigated.

  2. Characterization of thunderstorm induced Maxwell current densities in the middle atmosphere

    NASA Technical Reports Server (NTRS)

    Baginski, Michael Edward

    1989-01-01

    Middle atmospheric transient Maxwell current densities generated by lightning induced charge perturbations are investigated via a simulation of Maxwell's equations. A time domain finite element analysis is employed for the simulations. The atmosphere is modeled as a region contained within a right circular cylinder with a height of 110 km and radius of 80 km. A composite conductivity profile based on measured data is used when charge perturbations are centered about the vertical axis at altitudes of 6 and 10 km. The simulations indicate that the temporal structure of the Maxwell current density is relatively insensitive to altitude variation within the region considered. It is also shown that the electric field and Maxwell current density are not generally aligned.

  3. Perturbation theory for Maxwell's equations with a time-dependent current source

    NASA Astrophysics Data System (ADS)

    Roy, T.; Ghosh, S.; Bhattacharjee, J. K.

    2011-12-01

    Using a set of ideas discussed in the second volume of Feynman Lectures, we develop a perturbation-theoretic scheme for solving Maxwell's equations for time-dependent currents which are switched on at t = 0.

  4. Lifting of the Vlasov-Maxwell bracket by Lie-transform method

    NASA Astrophysics Data System (ADS)

    Brizard, A. J.; Morrison, P. J.; Burby, J. W.; de Guillebon, L.; Vittot, M.

    2016-12-01

    The Vlasov-Maxwell equations possess a Hamiltonian structure expressed in terms of a Hamiltonian functional and a functional bracket. In the present paper, the transformation (`lift') of the Vlasov-Maxwell bracket induced by the dynamical reduction of single-particle dynamics is investigated when the reduction is carried out by Lie-transform perturbation methods. The ultimate goal of this work is to provide an explicit pathway to the Hamiltonian formulations for the guiding-centre and gyrokinetic Vlasov-Maxwell equations, which have found important applications in our understanding of turbulent magnetized plasmas. Here, it is shown that the general form of the reduced Vlasov-Maxwell equations possesses a Hamiltonian structure defined in terms of a reduced Hamiltonian functional and a reduced bracket that automatically satisfies the standard bracket properties.

  5. Modèle de diélectrique associant les effets Poole-Frenkel et Maxwell-Wagner

    NASA Astrophysics Data System (ADS)

    Pillonnet, Alain; Ongaro, Roger; Garoum, Mohammed

    1992-06-01

    The model presented here combines Poole-Frenkel (PF) and Maxwell-Wagner (MW) effects to determine the equivalent conductivity σ of a plane double-layered dielectric. PF effect is introduced first under its usual form (Boltzmann statistics), and then under a more general form (Fermi-Dirac statistics). The curves log (σ) versus the electric field (sqrt{F}) generally display one or two linear parts, with the low-field slopes always larger than the high-field ones. These slopes are dependent on the layer's thickness ration and may greatly differ from slopes associated with PF effect in an homogeneous dielectric. The computer simulations show that this behaviour results from the fact that the potential can dominate successively in each layer. Le modèle présenté associe les effets Poole-Frenkel (PF) et Maxwell-Wagner (MW) dans la détermination de la conductivité équivalente σ d'un diélectrique plan à deux couches. L'effet PF y est introduit sous sa forme usuelle (statistique de Boltzmann), puis sous une forme plus générale (statistique de Fermi-Dirac). Les courbes log σ en fonction du champ électrique (sqrt{F}) présentent généralement une ou deux parties linéaires, la pente en bas champs étant toujours supérieure à la pente en hauts champs. Ces pentes sont fonctions du rapport des épaisseurs des couches et peuvent différer beaucoup des pentes relevant de l'effet PF dans un diélectrique homogène. Les simulations numériques montrent que ce comportement résulte du fait que le potentiel peut être successivement prépondérant dans chacune des couches.

  6. Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory

    NASA Astrophysics Data System (ADS)

    Tweney, Ryan D.

    2011-07-01

    James Clerk Maxwell `translated' Michael Faraday's experimentally-based field theory into the mathematical representation now known as `Maxwell's Equations.' Working with a variety of mathematical representations and physical models Maxwell extended the reach of Faraday's theory and brought it into consistency with other results in the physics of electricity and magnetism. Examination of Maxwell's procedures opens many issues about the role of mathematical representation in physics and the learning background required for its success. Specifically, Maxwell's training in `Cambridge University' mathematical physics emphasized the use of analogous equations across fields of physics and the repeated solving of extremely difficult problems in physics. Such training develops an array of overlearned mathematical representations supported by highly sophisticated cognitive mechanisms for the retrieval of relevant information from long term memory. For Maxwell, mathematics constituted a new form of representation in physics, enhancing the formal derivational and calculational role of mathematics and opening a cognitive means for the conduct of `experiments in the mind' and for sophisticated representations of theory.

  7. Generalized transport coefficients for inelastic Maxwell mixtures under shear flow.

    PubMed

    Garzó, Vicente; Trizac, Emmanuel

    2015-11-01

    The Boltzmann equation framework for inelastic Maxwell models is considered to determine the transport coefficients associated with the mass, momentum, and heat fluxes of a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. The Boltzmann equation is solved by means of a Chapman-Enskog-type expansion around the (local) shear flow distributions f(r)(0) for each species that retain all the hydrodynamic orders in the shear rate. Due to the anisotropy induced by the shear flow, tensorial quantities are required to describe the transport processes instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled equations, which can be analytically solved as functions of the shear rate a, the coefficients of restitution α(rs), and the parameters of the mixture (masses, diameters, and composition). Since the reference distribution functions f(r)(0) apply for arbitrary values of the shear rate and are not restricted to weak dissipation, the corresponding generalized coefficients turn out to be nonlinear functions of both a and α(rs). The dependence of the relevant elements of the three diffusion tensors on both the shear rate and dissipation is illustrated in the tracer limit case, the results showing that the deviation of the generalized transport coefficients from their forms for vanishing shear rates is in general significant. A comparison with the previous results obtained analytically for inelastic hard spheres by using Grad's moment method is carried out, showing a good agreement over a wide range of values for the coefficients of restitution. Finally, as an application of the theoretical expressions derived here for the transport coefficients, thermal diffusion segregation of an intruder immersed in a granular gas is also studied.

  8. Language Individuation and Marker Words: Shakespeare and His Maxwell's Demon

    PubMed Central

    Marsden, John; Budden, David; Craig, Hugh; Moscato, Pablo

    2013-01-01

    Background Within the structural and grammatical bounds of a common language, all authors develop their own distinctive writing styles. Whether the relative occurrence of common words can be measured to produce accurate models of authorship is of particular interest. This work introduces a new score that helps to highlight such variations in word occurrence, and is applied to produce models of authorship of a large group of plays from the Shakespearean era. Methodology A text corpus containing 55,055 unique words was generated from 168 plays from the Shakespearean era (16th and 17th centuries) of undisputed authorship. A new score, CM1, is introduced to measure variation patterns based on the frequency of occurrence of each word for the authors John Fletcher, Ben Jonson, Thomas Middleton and William Shakespeare, compared to the rest of the authors in the study (which provides a reference of relative word usage at that time). A total of 50 WEKA methods were applied for Fletcher, Jonson and Middleton, to identify those which were able to produce models yielding over 90% classification accuracy. This ensemble of WEKA methods was then applied to model Shakespearean authorship across all 168 plays, yielding a Matthews' correlation coefficient (MCC) performance of over 90%. Furthermore, the best model yielded an MCC of 99%. Conclusions Our results suggest that different authors, while adhering to the structural and grammatical bounds of a common language, develop measurably distinct styles by the tendency to over-utilise or avoid particular common words and phrasings. Considering language and the potential of words as an abstract chaotic system with a high entropy, similarities can be drawn to the Maxwell's Demon thought experiment; authors subconsciously favour or filter certain words, modifying the probability profile in ways that could reflect their individuality and style. PMID:23826143

  9. `Number States' and `Pilot Waves' Hidden in Maxwell's Classical Equations

    NASA Astrophysics Data System (ADS)

    Carroll, John E.

    2010-12-01

    Schrödingers equation with boundary conditions gives quantized energy states for electron waves, but Maxwell's wave equations have quantized states only by analogies with harmonic oscillators. This problem is addressed by a novel theory of wave-packets using diffracting Transverse Electric and Transverse Magnetic fields defined by axial H- and E-fields. All transverse fields and gradient operators can together be rotated about the propagation axis at frequencies, independent of the modal frequency. Without altering the axial fields, any helical motion propagates at the group velocity. This is quite different from single frequency helical modes (e.g. Laguerre Gaussian) travelling at the phase velocity. Reversing time and frequency, allows counter rotating helical solutions. These are referred to as adjoint or a fields that may interact and propagate with the classical causal reference or r fields. Overlapping and counter rotating r and a fields with slightly different frequencies interfere, leaving circular polarization states unaltered and creating a nodal structure in the transverse fields distinct from the nodal structure in the axial fields. Number states arise from requiring that transverse and axial nodes co-locate with integral spacings to form a wave-packet,. The a fields act as pilot waves for future potential positions of a quantized interaction between r and a fields. Uncertainty in the position of the overlap leads to conventional probabilistic quantum interpretations. The a fields are not fully determined until their detection with the r wave and this late determination can offer explanations for non-local entanglement.

  10. Global smooth flows for compressible Navier-Stokes-Maxwell equations

    NASA Astrophysics Data System (ADS)

    Xu, Jiang; Cao, Hongmei

    2016-08-01

    Umeda et al. (Jpn J Appl Math 1:435-457, 1984) considered a rather general class of symmetric hyperbolic-parabolic systems: A0zt+sum_{j=1}nAjz_{xj}+Lz=sum_{j,k=1}nB^{jk}z_{xjxk} and showed optimal decay rates with certain dissipative assumptions. In their results, the dissipation matrices {L} and {B^{jk}(j,k=1,ldots,n)} are both assumed to be real symmetric. So far there are no general results in case that {L} and {B^{jk}} are not necessarily symmetric, which is left open now. In this paper, we investigate compressible Navier-Stokes-Maxwell (N-S-M) equations arising in plasmas physics, which is a concrete example of hyperbolic-parabolic composite systems with non-symmetric dissipation. It is observed that the Cauchy problem for N-S-M equations admits the dissipative mechanism of regularity-loss type. Consequently, extra higher regularity is usually needed to obtain the optimal decay rate of {L1({mathbb{R}}^3)}-{L^2({mathbb{R}}^3)} type, in comparison with that for the global-in-time existence of smooth solutions. In this paper, we obtain the minimal decay regularity of global smooth solutions to N-S-M equations, with aid of {L^p({mathbb{R}}^n)}-{Lq({mathbb{R}}^n)}-{Lr({mathbb{R}}^n)} estimates. It is worth noting that the relation between decay derivative orders and the regularity index of initial data is firstly found in the optimal decay estimates.

  11. Information in statistical physics

    NASA Astrophysics Data System (ADS)

    Balian, Roger

    We review with a tutorial scope the information theory foundations of quantum statistical physics. Only a small proportion of the variables that characterize a system at the microscopic scale can be controlled, for both practical and theoretical reasons, and a probabilistic description involving the observers is required. The criterion of maximum von Neumann entropy is then used for making reasonable inferences. It means that no spurious information is introduced besides the known data. Its outcomes can be given a direct justification based on the principle of indifference of Laplace. We introduce the concept of relevant entropy associated with some set of relevant variables; it characterizes the information that is missing at the microscopic level when only these variables are known. For equilibrium problems, the relevant variables are the conserved ones, and the Second Law is recovered as a second step of the inference process. For non-equilibrium problems, the increase of the relevant entropy expresses an irretrievable loss of information from the relevant variables towards the irrelevant ones. Two examples illustrate the flexibility of the choice of relevant variables and the multiplicity of the associated entropies: the thermodynamic entropy (satisfying the Clausius-Duhem inequality) and the Boltzmann entropy (satisfying the H -theorem). The identification of entropy with missing information is also supported by the paradox of Maxwell's demon. Spin-echo experiments show that irreversibility itself is not an absolute concept: use of hidden information may overcome the arrow of time.

  12. Descriptive statistics.

    PubMed

    Shi, Runhua; McLarty, Jerry W

    2009-10-01

    In this article, we introduced basic concepts of statistics, type of distributions, and descriptive statistics. A few examples were also provided. The basic concepts presented herein are only a fraction of the concepts related to descriptive statistics. Also, there are many commonly used distributions not presented herein, such as Poisson distributions for rare events and exponential distributions, F distributions, and logistic distributions. More information can be found in many statistics books and publications.

  13. Statistical Software.

    ERIC Educational Resources Information Center

    Callamaras, Peter

    1983-01-01

    This buyer's guide to seven major types of statistics software packages for microcomputers reviews Edu-Ware Statistics 3.0; Financial Planning; Speed Stat; Statistics with DAISY; Human Systems Dynamics package of Stats Plus, ANOVA II, and REGRESS II; Maxistat; and Moore-Barnes' MBC Test Construction and MBC Correlation. (MBR)

  14. Statistical Diversions

    ERIC Educational Resources Information Center

    Petocz, Peter; Sowey, Eric

    2008-01-01

    As a branch of knowledge, Statistics is ubiquitous and its applications can be found in (almost) every field of human endeavour. In this article, the authors track down the possible source of the link between the "Siren song" and applications of Statistics. Answers to their previous five questions and five new questions on Statistics are presented.

  15. On Understanding: Maxwell on the Methods of Illustration and Scientific Metaphor

    NASA Astrophysics Data System (ADS)

    Cat, Jordi

    In this paper I examine the notion and role of metaphors and illustrations in Maxwell's works in exact science as a pathway into a broader and richer philosophical conception of a scientist and scientific practice. While some of these notions and methods are still at work in current scientific research-from economics and biology to quantum computation and quantum field theory-, here I have chosen to attest to their entrenchment and complexity in actual science by attempting to make some conceptual sense of Maxwell's own usage; this endeavour includes situating Maxwell's conceptions and applications in his own culture of Victorian science and philosophy. I trace Maxwell's notions to the formulation of the problem of understanding, or interpreting, abstract representations such as potential functions and Lagrangian equations. I articulate the solution in terms of abstract-concrete relations, where the concrete, in tune with Victorian British psychology and engineering, includes the muscular as well as the pictorial. This sets the basis for a conception of understanding in terms of unification and concrete modelling, or representation. I examine the relation of illustration to analogies and metaphors on which this account rests. Lastly, I stress and explain the importance of context-dependence, its consequences for realism-instrumentalism debates, and Maxwell's own emphasis on method.

  16. General eigenstates of Maxwell's equations in a two-constituent composite medium

    NASA Astrophysics Data System (ADS)

    Bergman, David J.; Farhi, Asaf

    2016-11-01

    Eigenstates of Maxwell's equations in the quasistatic regime were used recently to calculate the response of a Veselago Lens1 to the field produced by a time dependent point electric charge.2, 3 More recently, this approach was extended to calculate the non-quasistatic response of such a lens. This necessitated a calculation of the eigenstates of the full Maxwell equations in a flat slab structure where the electric permittivity ɛ1 of the slab differs from the electric permittivity ɛ2 of its surroundings while the magnetic permeability is equal to 1 everywhere.4 These eigenstates were used to calculate the response of a Veselago Lens to an oscillating point electric dipole source of electromagnetic (EM) waves. A result of these calculations was that, although images with subwavelength resolution are achievable, as first predicted by John Pendry,5 those images appear not at the points predicted by geometric optics. They appear, instead, at points which lie upon the slab surfaces. This is strongly connected to the fact that when ɛ1/ɛ2 = -1 a strong singularity occurs in Maxwell's equations: This value of ɛ1/ɛ2 is a mathemetical accumulation point for the EM eigenvalues.6 Unfortunately, many physicists are unaware of this crucial mathematical property of Maxwell's equations. In this article we describe how the non-quasistatic eigenstates of Maxwell's equations in a composite microstructure can be calculated for general two-constituent microstructures, where both ɛ and μ have different values in the two constituents.

  17. Time domain solutions of Maxwell's equations using a finite-volume formulation

    SciTech Connect

    Noack, R.W.; Anderson, D.A. )

    1992-01-01

    A new method for solving Maxwell's equations in the time domain has been developed. The method approximates the integral form of the time-dependent Maxwell's equations using a finite-volume formulation. The method utilizes a staggered mesh and requires boundary conditions on the electric field or the magnetic field but not both. Predictions from the present method have been compared to exact solutions for a full three-dimensional calculation of a sphere and experimental measurements for a generic missile body. These comparisons show that the method is capable of accurately solving the time-dependent Maxwell's equations and yields accurate predictions of the radar cross section for arbitrary geometries. 38 refs.

  18. Numerical Simulations of Light Bullets, Using The Full Vector, Time Dependent, Nonlinear Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)

    1994-01-01

    This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.

  19. Numerical Simulations of Light Bullets, Using the Full Vector, Time Dependent, Nonlinear Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)

    1994-01-01

    This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.

  20. Numerical Simulations of Light Bullets, Using The Full Vector, Time Dependent, Nonlinear Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)

    1995-01-01

    This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that we currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Karr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations.

  1. Energy requirement of control: Comments on Szilard's engine and Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Kish, L. B.; Granqvist, C. G.

    2012-06-01

    In mathematical physical analyses of Szilard's engine and Maxwell's demon, a general assumption (explicit or implicit) is that one can neglect the energy needed for relocating the piston in Szilard's engine and for driving the trap door in Maxwell's demon. If this basic assumption is wrong, then the conclusions of a vast literature on the implications of the second law of thermodynamics and of Landauer's erasure theorem are incorrect, too. Our analyses of the fundamental information physical aspects of various types of control within Szilard's engine and Maxwell's demon indicate that the entropy production due to the necessary generation of information yield much greater energy dissipation than the energy Szilard's engine is able to produce even if all sources of dissipation in the rest of these demons (due to measurement, decision, memory, etc.) are neglected.

  2. Statistical Diversions

    ERIC Educational Resources Information Center

    Petocz, Peter; Sowey, Eric

    2008-01-01

    In this article, the authors focus on hypothesis testing--that peculiarly statistical way of deciding things. Statistical methods for testing hypotheses were developed in the 1920s and 1930s by some of the most famous statisticians, in particular Ronald Fisher, Jerzy Neyman and Egon Pearson, who laid the foundations of almost all modern methods of…

  3. The Maxwell Montes region, surveyed by the Venera 15, Venera 16 orbiters

    NASA Astrophysics Data System (ADS)

    Kotelnikov, V. A.; Akim, E. L.; Aleksandrov, Y. N.; Armand, N. A.; Bazilevskij, A. T.; Bogomolov, A. F.; Vyshlov, A. S.; Dubrovin, V. M.; Zherikhin, N. V.; Zakharov, A. I.; Zimov, V. E.; Kaevitser, V. I.; Kovtunenko, V. M.; Kremnev, R. S.; Krivtsov, A. P.; Krylov, G. A.; Krymov, A. A.; Kucheryavenkova, I. L.; Molotov, E. P.; Petrov, G. M.; Rzhiga, O. N.; Selivanov, A. S.; Sidorenko, A. I.; Sinilo, V. P.; Sknarya, A. V.; Sokolov, G. A.; Sorokin, V. P.; Sukhanov, K. G.; Tikhonov, V. F.; Tyuflin, Y. S.; Feldman, B. Y.; Shakhovskoj, A. M.; Shubin, V. A.

    1984-12-01

    Between November 1983 and July 1984 the radar systems on the Venera 15 and 16 orbiters mapped much of the Venus northern hemisphere at high resolution. In particular, Maxwell Montes (the highest range on Venus) and a large part of the surrounding terrain exhibit horizontal tectonic deformations of compressive origin resembling mountain folds on the earth. The plains contiguous to Maxwell Montes may comprise basaltic extrusions, like the maria found on other terrestrial planets and the moon. The 100-km depression called Patera Cleopatra actually has a structure analogous to double-ring impact craters rather than volcanic calderas.

  4. Static Einstein-Maxwell Black Holes with No Spatial Isometries in AdS Space.

    PubMed

    Herdeiro, Carlos A R; Radu, Eugen

    2016-11-25

    We explicitly construct static black hole solutions to the fully nonlinear, D=4, Einstein-Maxwell-anti-de Sitter (AdS) equations that have no continuous spatial symmetries. These black holes have a smooth, topologically spherical horizon (section), but without isometries, and approach, asymptotically, global AdS spacetime. They are interpreted as bound states of a horizon with the Einstein-Maxwell-AdS solitons recently discovered, for appropriate boundary data. In sharp contrast to the uniqueness results for a Minkowski electrovacuum, the existence of these black holes shows that single, equilibrium, black hole solutions in an AdS electrovacuum admit an arbitrary multipole structure.

  5. Symmetric space property and an inverse scattering formulation of the SAS Einstein--Maxwell field equations

    SciTech Connect

    Eris, A.; Guerses, M.; Karasu, A.

    1984-05-01

    We formulate stationary axially symmetric (SAS) Einstein--Maxwell fields in the framework of harmonic mappings of Riemannian manifolds and show that the configuration space of the fields is a symmetric space. This result enables us to embed the configuration space into an eight-dimensional flat manifold and formulate SAS Einstein--Maxwell fields as a sigma-model. We then give, in a coordinate free way, a Belinskii--Zakharov type of an inverse scattering transform technique for the field equations supplemented by a reduction scheme similar to that of Zakharov--Mikhailov and Mikhailov--Yarimchuk.

  6. 3-D Maxwell fluid flow over an exponentially stretching surface using 3-stage Lobatto IIIA formula

    NASA Astrophysics Data System (ADS)

    Awais, M.; Hayat, T.; Ali, Aamir

    2016-05-01

    The present study looks at the three dimensional boundary layer flow driven by an exponentially stretching surface. An upper-convected Maxwell (UCM) fluid is considered. Characteristics here are characterized by rheological constitutive equations of upper convected Maxwell (UCM) fluid. Involved mathematical modeling constitutes a nonlinear differential system. 3-stage Lobatto IIIA formula is employed to construct the numerical solutions whereas analytic solutions are computed using HAM. Both solutions are compared and found in good agreement. The velocity components are analyzed for the Deborah number and ratio parameters.

  7. Electromagnetic duality symmetry and helicity conservation for the macroscopic Maxwell's equations.

    PubMed

    Fernandez-Corbaton, Ivan; Zambrana-Puyalto, Xavier; Tischler, Nora; Vidal, Xavier; Juan, Mathieu L; Molina-Terriza, Gabriel

    2013-08-09

    In this Letter, we show that the electromagnetic duality symmetry, broken in the microscopic Maxwell's equations by the presence of charges, can be restored for the macroscopic Maxwell's equations. The restoration of this symmetry is shown to be independent of the geometry of the problem. These results provide a tool for the study of light-matter interactions within the framework of symmetries and conservation laws. We illustrate its use by determining the helicity content of the natural modes of structures possessing spatial inversion symmetries and by elucidating the root causes for some surprising effects in the scattering off magnetic spheres.

  8. - criticality of AdS black hole in the Einstein-Maxwell-power-Yang-Mills gravity

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Yang, Zhan-Ying; Zou, De-Cheng; Xu, Wei; Yue, Rui-Hong

    2015-02-01

    We study the - critical behaivor of N-dimensional AdS black holes in Einstein-Maxwell-power-Yang-Mills gravity. Our results show the existence of the Van der Waals like small-large black hole phase transitions when taking some special values of charges of the Maxwell and Yang-Mills fields. Further to calculate the critical exponents of the black holes at the critical point, we find that they are the same as those in the Van der Waals liquid-gas system.

  9. Multivariate and matrix-variate analogues of Maxwell-Boltzmann and Raleigh densities

    NASA Astrophysics Data System (ADS)

    Mathai, A. M.; Princy, T.

    2017-02-01

    The Maxwell-Boltzmann and Raleigh densities are basic densities in many problems in Physics. A multivariate analogue and a rectangular matrix-variate analogue of these densities are explored in this article. The results may become useful in extending the usual theories, where these densities for the real scalar variable case occur, to multivariate and matrix variable situations. Various properties are studied and connection to the volumes of parallelotopes determined by p linearly independent random points in Euclidean n-space, n ≥ p, is also established. Structural decompositions of these random determinants and pathway extensions of Maxwell-Boltzmann and Raleigh densities are also considered.

  10. Statistics Clinic

    NASA Technical Reports Server (NTRS)

    Feiveson, Alan H.; Foy, Millennia; Ploutz-Snyder, Robert; Fiedler, James

    2014-01-01

    Do you have elevated p-values? Is the data analysis process getting you down? Do you experience anxiety when you need to respond to criticism of statistical methods in your manuscript? You may be suffering from Insufficient Statistical Support Syndrome (ISSS). For symptomatic relief of ISSS, come for a free consultation with JSC biostatisticians at our help desk during the poster sessions at the HRP Investigators Workshop. Get answers to common questions about sample size, missing data, multiple testing, when to trust the results of your analyses and more. Side effects may include sudden loss of statistics anxiety, improved interpretation of your data, and increased confidence in your results.

  11. Aluminum honeycomb reflector panels on James Clerk Maxwell Telescope

    NASA Astrophysics Data System (ADS)

    Greenhalgh, R. Justin S.

    1993-10-01

    The accuracy requirements and design philosophy of the JCMT reflector structure are briefly reviewed, leading to a steel space-frame with separate reflector panels. The choice of material for the panels is discussed, with particular emphasis on the properties of aluminum honeycomb composites. The development of the manufacturing process and the details of the process are described. Finally, statistics on the results of the manufacturing process are given.

  12. Optical Nonlinear Wakefield Vortices: Results from Full-Wave Vector Maxwell Equation Simulations in Two Spatial Dimensions and Time,

    DTIC Science & Technology

    In this paper we report the first multi-dimensional, full-wave, vector Maxwell’s equation solutions to problems describing the interaction of ultra...time domain (NL-FDTD) method which combines a nonlinear generalization of a standard, FDTD, full-wave, vector, linear Maxwell’s equation solver with

  13. 77 FR 46114 - Notice of Intent to Repatriate Cultural Items: Maxwell Museum of Anthropology, University of New...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-02

    ...-1100-665] Notice of Intent to Repatriate Cultural Items: Maxwell Museum of Anthropology, University of... Maxwell Museum of Anthropology, in consultation with the Pueblo of Santa Ana, New Mexico, has determined... Anthropology at the address below by September 4, 2012. ADDRESSES: David Phillips, Curator of...

  14. Quick Statistics

    MedlinePlus

    ... population, or about 25 million Americans, has experienced tinnitus lasting at least five minutes in the past ... by NIDCD Epidemiology and Statistics Program staff: (1) tinnitus prevalence was obtained from the 2008 National Health ...

  15. Series Solution for Rotating Flow of an Upper Convected Maxwell Fluid over a Stretching Sheet

    NASA Astrophysics Data System (ADS)

    Sajid, M.; Z., Iqbal; Hayat, T.; Obaidat, S.

    2011-10-01

    The equations for two-dimensional flow of an upper convected Maxwell (UCM) fluid in a rotating frame are modeled. The resulting equations are first simplified by a boundary layer approach and then solved by a homotopy analysis method (HAM). Convergence of series solution is discussed through residual error curves. The results of the influence of viscoelastic and rotation parameters are plotted and discussed.

  16. A numerical Maxwell Schrödinger model for intense laser matter interaction and propagation

    NASA Astrophysics Data System (ADS)

    Lorin, E.; Chelkowski, S.; Bandrauk, A.

    2007-12-01

    We present in this paper an original ab initio Maxwell-Schrödinger model and a methodology to simulate intense ultrashort laser pulses interacting with a 3D H +2-gas in the nonlinear nonperturbative regime under and beyond Born-Oppenheimer approximation. The model we present is the first one to our knowledge (excepted in [E. Lorin, S. Chelkowski, A. Bandrauk, A Maxwell-Schrödinger model for non-perturbative laser-molecule interaction and some methods of numerical computation, Proceeding CRM, vol. 41, American Mathematics Society, 2007], where a one-dimensional version is presented) to be totally nonperturbative, vectorial and multidimensional, taking into account ionization, and high order nonlinearities going far beyond classical nonlinear Maxwell or Schrödinger models. After a presentation of the model and a short mathematical study, we examine some numerical approximations for its computation. In particular, we focus on the polarization computation allowing an efficient coupling between the Maxwell and time dependent Schrödinger equations (TDSE), and on an efficient parallelization. Examples of numerical computations of high order harmonic generation and of electric field propagation are presented for one molecule and up to 512, thus highlighting cooperative effects in harmonic generation at high order.

  17. An Exact Solution of Einstein-Maxwell Gravity Coupled to a Scalar Field

    NASA Technical Reports Server (NTRS)

    Turyshev, S. G.

    1995-01-01

    The general solution to low-energy string theory representing static spherically symmetric solution of the Einstein-Maxwell gravity with a massless scalar field has been found. Some of the partial cases appear to coincide with known solutions to black holes, naked singularities, and gravity and electromagnetic fields.

  18. The Space-Time CE/SE Method for Solving Maxwell's Equations in Time-Domain

    NASA Technical Reports Server (NTRS)

    Wang, X. Y.; Chen, C. L.; Liu, Yen

    2002-01-01

    An innovative finite-volume-type numerical method named as the space-time conservation element and solution element (CE/SE) method is applied to solve time-dependent Maxwell's equations in this paper. Test problems of electromagnetics scattering and antenna radiation are solved for validations. Numerical results are presented and compared with the analytical solutions, showing very good agreements.

  19. A Problem and Its Solution Involving Maxwell's Equations and an Inhomogeneous Medium.

    ERIC Educational Resources Information Center

    Williamson, W., Jr.

    1980-01-01

    Maxwell's equation are solved for an inhomogeneous medium which has a coordinate-dependent dielectric function. The problem and its solutions are given in a format which should make it useful as an intermediate or advanced level problem in an electrodynamics course. (Author/SK)

  20. Fermions Tunneling from Non-Stationary Dilaton-Maxwell Black Hole via General Tortoise Coordinate Transformation

    NASA Astrophysics Data System (ADS)

    Lin, Kai; Yang, Shu-Zheng

    2009-10-01

    Fermions tunneling of the non-stationary Dilaton-Maxwell black hole is investigated with general tortoise coordinate transformation. The Dirac equation is simplified by semiclassical approximation so that the Hamilton-Jacobi equation is generated. Finally the tunneling rate and the Hawking temperature is calculated.

  1. Simple Derivation of the Maxwell Stress Tensor and Electrostrictive Effects in Crystals

    ERIC Educational Resources Information Center

    Juretschke, H. J.

    1977-01-01

    Shows that local equilibrium and energy considerations in an elastic dielectric crystal lead to a simple derivation of the Maxwell stress tensor in anisotropic dielectric solids. The resulting equilibrium stress-strain relations are applied to determine the deformations of a charged parallel plate capacitor. (MLH)

  2. Maxwell's Relations for a van der Waals Gas and a Nuclear Paramagnetic System.

    ERIC Educational Resources Information Center

    Herlihy, James; And Others

    1981-01-01

    Since Maxwell's relations are derived in general form from the first to second laws, and students often wonder what they mean and how they are used, appropriate partition functions for van der Waals gas and the nuclear paramagnetic system are used to obtain entropy expressions and equations of state. (Author/SK)

  3. 77 FR 46116 - Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New Mexico...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-02

    ...-1100-665] Notice of Inventory Completion: Maxwell Museum of Anthropology, University of New Mexico... Anthropology has completed an inventory of human remains in consultation with the appropriate Indian tribe, and... Museum of Anthropology at the address below by September 4, 2012. ADDRESSES: Heather Edgar,...

  4. Self-dual Maxwell-Chern-Simons solitons from a Lorentz-violating model

    NASA Astrophysics Data System (ADS)

    Casana, Rodolfo; Sourrouille, Lucas

    2013-10-01

    Self-dual abelian Higgs system, involving both the Maxwell and Chern-Simons terms are obtained from Carroll-Field-Jackiw theory by dimensional reduction. Bogomol'nyi-type equations are studied from theoretical and numerical point of view. In particular, we show that the solutions of these equations are Nielsen-Olesen vortices with electric charge.

  5. 3D FEM-BEM-coupling method to solve magnetostatic Maxwell equations

    NASA Astrophysics Data System (ADS)

    Bruckner, Florian; Vogler, Christoph; Feischl, Michael; Praetorius, Dirk; Bergmair, Bernhard; Huber, Thomas; Fuger, Markus; Suess, Dieter

    2012-05-01

    3D magnetostatic Maxwell equations are solved using the direct Johnson-Nédélec FEM-BEM coupling method and a reduced scalar potential approach. The occurring BEM matrices are calculated analytically and approximated by H-matrices using the ACA+ algorithm. In addition a proper preconditioning method is suggested that allows to solve large-scale problems using iterative solvers.

  6. Reply to Comment on ``Maxwell, Electromagnetism, and Fluid Flow in Resistive Media''

    NASA Astrophysics Data System (ADS)

    Narasimhan, T. N.

    2004-04-01

    Glenn Brown takes issue with my statement, ``It is hoped that Maxwell's contribution to the foundations of fluids in porous media will receive due attention, and that his novel approach will lead to new insights.'' He considers that, because Maxwell did not explicitly develop his theory for fluid flow in porous media, his ideas should not be treated as a contribution in that area. Brown contends that doing so is a disservice to Darcy, and is revisionist. Brown and I differ in the way we perceive science. He looks at the material I have presented from an ideological perspective of upholding Darcy's position in history. On the other hand, I do not question Darcy's valid contribution. Rather, I presented some of Maxwell's fascinating ideas that are relevant to the study of fluid flow in porous media, published in the same year Darcy published his seminal work. I have shown that the relevance of Maxwell's ideas to flow in porous media has gone unnoticed in the literature. Scientists are fallible human beings, and important ideas and thoughts are occasionally overlooked. When, on a rare occasion, we chance upon such an oversight, it is part of our scientific enterprise to bring the finding to the attention of the scientific community. It is up to the community to judge the historical significance of the new information.

  7. Using molecular dynamics to obtain Maxwell-Stefan diffusion coefficients in liquid systems

    NASA Astrophysics Data System (ADS)

    van de Ven-Lucassen Thijs, Irma M. J. J.; Vlugt Antonius, J. H.; van der Zanden Piet, J. J.; Kerkhof, J. A. M.

    Two methods are compared for the calculation of Maxwell-Stefan diffusion coefficients. The first method is a non-equilibrium molecular dynamics (NEMD) algorithm, in which the system is driven away from equilibrium and the system response is monitored. The second method is the equilibrium molecular dynamics (EMD) calculation of the appropriate GreenKubo equation. Simulations were performed for systems of 250 and 300 Lennard-Jones particles at various densities and temperatures. The systems were divided into two or three components by attaching a colour label to the particles. Since a colour label plays no role in the dynamics, the Maxwell-Stefan diffusion coefficients of the binary and ternary systems are equal to the self-diffusion coefficient. In dense fluids, the system response to an external perturbation is not a first-order process, and the diffusion coefficients cannot be determined from the short term response in the NEMD method. Only the long term response can be used, after a steady state has been reached. In binary systems the Maxwell-Stefan diffusion coefficients, determined by the Green-Kubo (EMD) method, are more accurate than the NEMD coefficients. Since in the NEMD method only the long term response can be used, the GreenKubo method is also less time consuming and is therefore preferred for the calculation of the Maxwell-Stefan diffusion coefficients. In ternary systems the Green-Kubo method is tested for the 250 particle system. The Maxwell-Stefan diffusion coefficients agree well with the selfdiffusion coefficient. For low mole fractions of the coloured components the diffusion coefficients were less accurate.

  8. Venus' radar-bright highlands: Different signatures and materials on Ovda Regio and on Maxwell Montes

    NASA Astrophysics Data System (ADS)

    Treiman, Allan; Harrington, Elise; Sharpton, Virgil

    2016-12-01

    Venus' highlands appear much brighter than its lowland plains in reflected radar, which has been explained by several conflicting hypotheses. We study this transition at higher spatial and elevation resolution than previously possible by combining Magellan synthetic aperture radar (SAR) images with Magellan SAR stereo elevations. We confirm that SAR backscatter over Ovda Regio (5°N to 15°S) grades from low to high as elevation increases (2-4.5 km above the datum), and then drops precipitously above ∼4.5 km (T= ∼702 K). This pattern is consistent with presence of a substance that undergoes a phase transition from ferroelectric to normal dielectric at ∼700 K; the mineral chlorapatite is a likely candidate. This pattern is seen across Ovda, on other near-equatorial highlands, and on some shield volcanoes like the Tepev Montes. We also confirm that Maxwell Montes (60-68°N) shows a different pattern; its surface transitions abruptly from low backscatter to high backscatter at ∼4.5 km above the datum, and remains so to nearly its highest elevations (∼10 km). This pattern is consistent with the presence of a semiconductor material either precipitated from the atmosphere (e.g., a frost) or produced by atmosphere-surface interaction. If a ferroelectric substance were in the rock at Maxwell (as at Ovda), it could be invisible beneath the coating of semiconductor material. However, the absence of a semiconductor material on Ovda requires either that [1] the atmosphere compositions at Maxwell and Ovda are substantially different, or [2] that the semiconductor at Maxwell forms by atmosphere-surface reaction (not as an atmospheric precipitate) and that the surface materials at Ovda and Maxwell are substantially different.

  9. Statistics Revelations

    ERIC Educational Resources Information Center

    Chicot, Katie; Holmes, Hilary

    2012-01-01

    The use, and misuse, of statistics is commonplace, yet in the printed format data representations can be either over simplified, supposedly for impact, or so complex as to lead to boredom, supposedly for completeness and accuracy. In this article the link to the video clip shows how dynamic visual representations can enliven and enhance the…

  10. Statistical Inference

    NASA Astrophysics Data System (ADS)

    Khan, Shahjahan

    Often scientific information on various data generating processes are presented in the from of numerical and categorical data. Except for some very rare occasions, generally such data represent a small part of the population, or selected outcomes of any data generating process. Although, valuable and useful information is lurking in the array of scientific data, generally, they are unavailable to the users. Appropriate statistical methods are essential to reveal the hidden "jewels" in the mess of the row data. Exploratory data analysis methods are used to uncover such valuable characteristics of the observed data. Statistical inference provides techniques to make valid conclusions about the unknown characteristics or parameters of the population from which scientifically drawn sample data are selected. Usually, statistical inference includes estimation of population parameters as well as performing test of hypotheses on the parameters. However, prediction of future responses and determining the prediction distributions are also part of statistical inference. Both Classical or Frequentists and Bayesian approaches are used in statistical inference. The commonly used Classical approach is based on the sample data alone. In contrast, increasingly popular Beyesian approach uses prior distribution on the parameters along with the sample data to make inferences. The non-parametric and robust methods are also being used in situations where commonly used model assumptions are unsupported. In this chapter,we cover the philosophical andmethodological aspects of both the Classical and Bayesian approaches.Moreover, some aspects of predictive inference are also included. In the absence of any evidence to support assumptions regarding the distribution of the underlying population, or if the variable is measured only in ordinal scale, non-parametric methods are used. Robust methods are employed to avoid any significant changes in the results due to deviations from the model

  11. Statistical Inference

    NASA Astrophysics Data System (ADS)

    Khan, Shahjahan

    Often scientific information on various data generating processes are presented in the from of numerical and categorical data. Except for some very rare occasions, generally such data represent a small part of the population, or selected outcomes of any data generating process. Although, valuable and useful information is lurking in the array of scientific data, generally, they are unavailable to the users. Appropriate statistical methods are essential to reveal the hidden “jewels” in the mess of the row data. Exploratory data analysis methods are used to uncover such valuable characteristics of the observed data. Statistical inference provides techniques to make valid conclusions about the unknown characteristics or parameters of the population from which scientifically drawn sample data are selected. Usually, statistical inference includes estimation of population parameters as well as performing test of hypotheses on the parameters. However, prediction of future responses and determining the prediction distributions are also part of statistical inference. Both Classical or Frequentists and Bayesian approaches are used in statistical inference. The commonly used Classical approach is based on the sample data alone. In contrast, increasingly popular Beyesian approach uses prior distribution on the parameters along with the sample data to make inferences. The non-parametric and robust methods are also being used in situations where commonly used model assumptions are unsupported. In this chapter,we cover the philosophical andmethodological aspects of both the Classical and Bayesian approaches.Moreover, some aspects of predictive inference are also included. In the absence of any evidence to support assumptions regarding the distribution of the underlying population, or if the variable is measured only in ordinal scale, non-parametric methods are used. Robust methods are employed to avoid any significant changes in the results due to deviations from the model

  12. [Descriptive statistics].

    PubMed

    Rendón-Macías, Mario Enrique; Villasís-Keever, Miguel Ángel; Miranda-Novales, María Guadalupe

    2016-01-01

    Descriptive statistics is the branch of statistics that gives recommendations on how to summarize clearly and simply research data in tables, figures, charts, or graphs. Before performing a descriptive analysis it is paramount to summarize its goal or goals, and to identify the measurement scales of the different variables recorded in the study. Tables or charts aim to provide timely information on the results of an investigation. The graphs show trends and can be histograms, pie charts, "box and whiskers" plots, line graphs, or scatter plots. Images serve as examples to reinforce concepts or facts. The choice of a chart, graph, or image must be based on the study objectives. Usually it is not recommended to use more than seven in an article, also depending on its length.

  13. Order Statistics and Nonparametric Statistics.

    DTIC Science & Technology

    2014-09-26

    Topics investigated include the following: Probability that a fuze will fire; moving order statistics; distribution theory and properties of the...problem posed by an Army Scientist: A fuze will fire when at least n-i (or n-2) of n detonators function within time span t. What is the probability of

  14. Statistical Optics

    NASA Astrophysics Data System (ADS)

    Goodman, Joseph W.

    2000-07-01

    The Wiley Classics Library consists of selected books that have become recognized classics in their respective fields. With these new unabridged and inexpensive editions, Wiley hopes to extend the life of these important works by making them available to future generations of mathematicians and scientists. Currently available in the Series: T. W. Anderson The Statistical Analysis of Time Series T. S. Arthanari & Yadolah Dodge Mathematical Programming in Statistics Emil Artin Geometric Algebra Norman T. J. Bailey The Elements of Stochastic Processes with Applications to the Natural Sciences Robert G. Bartle The Elements of Integration and Lebesgue Measure George E. P. Box & Norman R. Draper Evolutionary Operation: A Statistical Method for Process Improvement George E. P. Box & George C. Tiao Bayesian Inference in Statistical Analysis R. W. Carter Finite Groups of Lie Type: Conjugacy Classes and Complex Characters R. W. Carter Simple Groups of Lie Type William G. Cochran & Gertrude M. Cox Experimental Designs, Second Edition Richard Courant Differential and Integral Calculus, Volume I RIchard Courant Differential and Integral Calculus, Volume II Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume I Richard Courant & D. Hilbert Methods of Mathematical Physics, Volume II D. R. Cox Planning of Experiments Harold S. M. Coxeter Introduction to Geometry, Second Edition Charles W. Curtis & Irving Reiner Representation Theory of Finite Groups and Associative Algebras Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume I Charles W. Curtis & Irving Reiner Methods of Representation Theory with Applications to Finite Groups and Orders, Volume II Cuthbert Daniel Fitting Equations to Data: Computer Analysis of Multifactor Data, Second Edition Bruno de Finetti Theory of Probability, Volume I Bruno de Finetti Theory of Probability, Volume 2 W. Edwards Deming Sample Design in Business Research

  15. Hybrid resonance and long-time asymptotic of the solution to Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Després, Bruno; Weder, Ricardo

    2016-03-01

    We study the long-time asymptotic of the solutions to Maxwell's equation in the case of an upper-hybrid resonance in the cold plasma model. We base our analysis in the transfer to the time domain of the recent results of B. Després, L.M. Imbert-Gérard and R. Weder (2014) [15], where the singular solutions to Maxwell's equations in the frequency domain were constructed by means of a limiting absorption principle and a formula for the heating of the plasma in the limit of vanishing collision frequency was obtained. Currently there is considerable interest in these problems, in particular, because upper-hybrid resonances are a possible scenario for the heating of plasmas, and since they can be a model for the diagnostics involving wave scattering in plasmas.

  16. Circularly polarized few-cycle optical rogue waves: Rotating reduced Maxwell-Bloch equations

    NASA Astrophysics Data System (ADS)

    Xu, Shuwei; Porsezian, K.; He, Jingsong; Cheng, Yi

    2013-12-01

    The rotating reduced Maxwell-Bloch (RMB) equations, which describe the propagation of few-cycle optical pulses in a transparent media with two isotropic polarized electronic field components, are derived from a system of complete Maxwell-Bloch equations without using the slowly varying envelope approximations. Two hierarchies of the obtained rational solutions, including rogue waves, which are also called few-cycle optical rogue waves, of the rotating RMB equations are constructed explicitly through degenerate Darboux transformation. In addition to the above, the dynamical evolution of the first-, second-, and third-order few-cycle optical rogue waves are constructed with different patterns. For an electric field E in the three lower-order rogue waves, we find that rogue waves correspond to localized large amplitude oscillations of the polarized electric fields. Further a complementary relationship of two electric field components of rogue waves is discussed in terms of analytical formulas as well as numerical figures.

  17. New class of exact solutions in Einstein-Maxwell-dilaton theory

    NASA Astrophysics Data System (ADS)

    Ghezelbash, A. M.

    2017-03-01

    We find new solutions to the five-dimensional Einstein-Maxwell-dilaton theory with cosmological constant where the dilaton field couples to the electromagnetic field as well as to the cosmological term with two different coupling constants. The five-dimensional spacetime is nonstationary and is a conformally regular spacetime, everywhere. Both the dilaton field and the electromagnetic field depend on time and two spatial directions. The cosmological constant takes a positive, negative, or zero value, depending on the value of the coupling constant. We study the physical properties of the spacetime, and we show that the solutions are unique in five dimensions and that they cannot be uplifted to higher-dimensional Einstein-Maxwell theory or Einstein gravity in the presence of the cosmological constant. Moreover, we construct new solutions to the theory in which both coupling constants are equal.

  18. Maxwell and the normal distribution: A colored story of probability, independence, and tendency toward equilibrium

    NASA Astrophysics Data System (ADS)

    Gyenis, Balázs

    2017-02-01

    We investigate Maxwell's attempt to justify the mathematical assumptions behind his 1860 Proposition IV according to which the velocity components of colliding particles follow the normal distribution. Contrary to the commonly held view we find that his molecular collision model plays a crucial role in reaching this conclusion, and that his model assumptions also permit inference to equalization of mean kinetic energies (temperatures), which is what he intended to prove in his discredited and widely ignored Proposition VI. If we take a charitable reading of his own proof of Proposition VI then it was Maxwell, and not Boltzmann, who gave the first proof of a tendency towards equilibrium, a sort of H-theorem. We also call attention to a potential conflation of notions of probabilistic and value independence in relevant prior works of his contemporaries and of his own, and argue that this conflation might have impacted his adoption of the suspect independence assumption of Proposition IV.

  19. Maxwell's fish-eye lens and the mirage of perfect imaging

    NASA Astrophysics Data System (ADS)

    Merlin, R.

    2011-02-01

    Recent claims that Maxwell's fish-eye is a perfect lens, capable of providing images with deep subwavelength resolution, are examined. We show that the imaging properties of a dispersionless fish-eye are very similar to those of an ideal spherical cavity. Using this correspondence, we prove that the correct solution to Maxwell equations in the fish-eye gives image sizes that are consistent with the standard diffraction limit. Perfect focusing is an optical illusion that results from placing a time-reversed source at the position of the geometrical image which, when combined with the field due to the primary (object) source, mimics the behavior of a perfect drain. Issues of causality are briefly discussed. We also demonstrate that passive outlets are not a good alternative to time-reversed sources for broadband drain-like behavior and that, even if they were, they could not do a better job than conventional optical systems at providing high resolution.

  20. Maxwell's second- and third-order equations of transfer for non-Maxwellian gases

    NASA Technical Reports Server (NTRS)

    Baganoff, D.

    1992-01-01

    Condensed algebraic forms for Maxwell's second- and third-order equations of transfer are developed for the case of molecules described by either elastic hard spheres, inverse-power potentials, or by Bird's variable hard-sphere model. These hardly reduced, yet exact, equations provide a new point of origin, when using the moment method, in seeking approximate solutions in the kinetic theory of gases for molecular models that are physically more realistic than that provided by the Maxwell model. An important by-product of the analysis when using these second- and third-order relations is that a clear mathematical connection develops between Bird's variable hard-sphere model and that for the inverse-power potential.

  1. Formalism of two potentials for the numerical solution of Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, A. N.; Trashkeev, S. I.

    2013-11-01

    A new formulation of Maxwell's equations based on the introduction of two vector and two scalar potentials is proposed. As a result, the electromagnetic field equations are written as a hyperbolic system that contains, in contrast to the original Maxwell system, only evolution equations and does not involve equations in the form of differential constraints. This makes the new equations especially convenient for the numerical simulation of electromagnetic processes. Specifically, they can be solved by applying powerful modern shock-capturing methods based on the approximation of spatial derivatives by upwind differences. The cases of an electromagnetic field in a vacuum and an inhomogeneous material are considered. Examples are given in which electromagnetic wave propagation is simulated by solving the formulated system of equations with the help of modern high-order accurate schemes.

  2. Experimental Rectification of Entropy Production by Maxwell's Demon in a Quantum System

    NASA Astrophysics Data System (ADS)

    Camati, Patrice A.; Peterson, John P. S.; Batalhão, Tiago B.; Micadei, Kaonan; Souza, Alexandre M.; Sarthour, Roberto S.; Oliveira, Ivan S.; Serra, Roberto M.

    2016-12-01

    Maxwell's demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this "intelligent observer" is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell's demon in a quantum system. The demon is experimentally implemented as a spin-1 /2 quantum memory that acquires information, and employs it to control the dynamics of another spin-1 /2 system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.

  3. Sources of gravitational waves in asymptotically flat Einstein-Maxwell spacetime

    NASA Astrophysics Data System (ADS)

    Quiroga, G. D.

    2017-02-01

    In this work, the dynamic of isolated systems in general relativity is described when gravitational radiation and electromagnetic fields are present. In this construction, the asymptotic fields received at null infinity together with the regularized null cone cuts equation, and the center of mass of an asymptotically flat Einstein-Maxwell spacetime are used. A set of equations are derived in the low speed regime, linking their time evolution to the emitted gravitational radiation and to the Maxwell fields received at infinity. These equations should be useful when describing the dynamic of compact sources, such as the final moments of binary coalescence and the evolution of the final black hole. Additionally, we compare our equations with those coming from a similar approach given by Newman, finding some differences in the motion of the center of mass and spin of the gravitational system.

  4. A new type of massive spin-one boson: And its relation with Maxwell equations

    SciTech Connect

    Ahluwalia, D.V.

    1995-10-01

    First, the author showed that in the (1, 0) {circle_plus} (0, 1) representation space there exist not one but two theories for charged particles. In the Weinberg construct, the boson and its antiboson carry same relative intrinsic parity, whereas in the author`s construct the relative intrinsic parities of the boson and its antiboson are opposite. These results originate from the commutativity of the operations of Charge conjugation and Parity in Weinberg`s theory, and from the anti-commutativity of the operations of Charge conjugation and Parity in the author`s theory. The author thus claims that he has constructed a first non-trivial quantum theory of fields for the Wigner-type particles. Second, the massless limit of both theories seems formally identical and suggests a fundamental modification of Maxwell equations. At its simplest level, the modification to Maxwell equations enters via additional boundary condition(s).

  5. An asymptotic preserving scheme for the relativistic Vlasov-Maxwell equations in the classical limit

    NASA Astrophysics Data System (ADS)

    Crouseilles, Nicolas; Einkemmer, Lukas; Faou, Erwan

    2016-12-01

    We consider the relativistic Vlasov-Maxwell (RVM) equations in the limit when the light velocity c goes to infinity. In this regime, the RVM system converges towards the Vlasov-Poisson system and the aim of this paper is to construct asymptotic preserving numerical schemes that are robust with respect to this limit. Our approach relies on a time splitting approach for the RVM system employing an implicit time integrator for Maxwell's equations in order to damp the higher and higher frequencies present in the numerical solution. A number of numerical simulations are conducted in order to investigate the performances of our numerical scheme both in the relativistic as well as in the classical limit regime. In addition, we derive the dispersion relation of the Weibel instability for the continuous and the discretized problem.

  6. Finite-surface method for the Maxwell equations with corner singularities

    NASA Technical Reports Server (NTRS)

    Vinokur, Marcel; Yarrow, Maurice

    1994-01-01

    The finite-surface method for the two-dimensional Maxwell equations in generalized coordinates is extended to treat perfect conductor boundaries with sharp corners. Known singular forms of the grid and the electromagnetic fields in the neighborhood of each corner are used to obtain accurate approximations to the surface and line integrals appearing in the method. Numerical results are presented for a harmonic plane wave incident on a finite flat plate. Comparisons with exact solutions show good agreement.

  7. Slow Time-Scale Source-Free Maxwell Equations for a Nonstationary, Inhomogeneous Medium.

    DTIC Science & Technology

    1983-02-01

    along the same lines, gives -(- 4n E+ 1 2 ) at V(V.E) 47t a2 L2 E. (3.10) 12 NSWC TR 83-100 L.s. (3.9) and (3.10) are exact consequences of Maxwell’s ... equation for a nonstationary inhomoheneous medium characterized by constitutive relations defined by Eqs. (2.3) and (2.5). The special case o-0 and

  8. Magnetohydrodynamic flow of generalized Maxwell fluids in a rectangular micropump under an AC electric field

    NASA Astrophysics Data System (ADS)

    Zhao, Guangpu; Jian, Yongjun; Chang, Long; Buren, Mandula

    2015-08-01

    By using the method of separation of variables, an analytical solution for the magnetohydrodynamic (MHD) flow of the generalized Maxwell fluids under AC electric field through a two-dimensional rectangular micropump is reduced. By the numerical computation, the variations of velocity profiles with the electrical oscillating Reynolds number Re, the Hartmann number Ha, the dimensionless relaxation time De are studied graphically. Further, the comparison with available experimental data and relevant researches is presented.

  9. Geometric Integration Of The Vlasov-Maxwell System With A Variational Particle-in-cell Scheme

    SciTech Connect

    J. Squire, H. Qin and W.M. Tang

    2012-03-27

    A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of Discrete Exterior Calculus [1], the field solver, interpolation scheme and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law.

  10. Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme

    SciTech Connect

    Squire, J.; Tang, W. M.; Qin, H.

    2012-08-15

    A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of discrete exterior calculus [Desbrun et al., e-print arXiv:math/0508341 (2005)], the field solver, interpolation scheme, and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law.

  11. Characterization of carbon-based electrochemical capacitor technology from Maxwell Energy Products, Inc.

    SciTech Connect

    Wright, R.B.; Murphy, T.C.

    1998-04-01

    The electrochemical capacitor devices described in this report were deliverables from the US Department of Energy--Idaho Operations Office (DOE-ID) Contract No. DE-AC07-92ID13404 as part of the US Department of Energy`s (DOE) High Power Energy Storage Program. The Idaho national Engineering and Environmental Laboratory (INEEL) has responsibility for technical management, testing, and evaluation of high-power batteries and electrochemical capacitors under this Program. The DOE has developed various electrochemical capacitors as candidate power assist devices for the Partnership for a New Generation of Vehicles (PNGV) fast response engine requirement. This contract with Maxwell Energy Products, Inc. (Maxwell) was intended to develop a high-energy-density, high-power-density ultracapacitor that is capable of load leveling batteries in electric vehicles. The performance criteria for this device are delivery of 5 W {center_dot} h/kg of useful energy that can be used by the vehicle at an average power rating of 600 W/kg. The capacitor must also have an overall charge/discharge efficiency of 90%, and a useful life of more than 100,000 discharge cycles. The deliverables reported on here are those prepared by Maxwell Energy Products, Inc. at various stages of their developmental program. Deliverables were sent to the INEEL`s Energy Storage Technologies (EST) Laboratory for independent testing and evaluation. This report describes performance testing on three sets of capacitors delivered over a two year period. Additional testing has been done on Set {number_sign}2 described herein, as well as on an additional deliverable from Maxwell. These tests results will be documented in a follow-up report.

  12. Second order scheme for Maxwell's equations with discontinuous dielectric permittivity on structured meshes

    NASA Astrophysics Data System (ADS)

    Ismagilov, Timur Z.

    2013-10-01

    A second order finite volume scheme for numerical solution of Maxwell's equations with discontinuous dielectric permittivity on structured meshes is suggested. The scheme is based on approaches of Godunov, Lax-Wendroff and Van Leer. The distinctive feature of the suggested scheme is calculation and limitation of derivatives that ensures second order of approximation even in the cells adjacent to dielectric permittivity discontinuity. Numerical tests for problems with linear and curvilinear dielectric permittivity discontinuities confirm second order of approximation.

  13. Regularization method for solving the quasi-stationary Maxwell equations in an inhomogeneous conducting medium

    NASA Astrophysics Data System (ADS)

    Ivanov, M. I.; Kremer, I. A.; Urev, M. V.

    2012-03-01

    Nedelec vector finite elements are used for the numerical solution of a regularized version of the quasi-stationary Maxwell equations written in terms of a scalar and a vector magnetic potential with special calibration taking into account the conductivity of the medium. An optimal energy estimate for the error of the approximate solution in Lipschitz polyhedral domains is established. Numerical results are presented that demonstrate the stability of the method.

  14. Power of an optical Maxwell's demon in the presence of photon-number correlations

    NASA Astrophysics Data System (ADS)

    Shu, Angeline; Dai, Jibo; Scarani, Valerio

    2017-02-01

    We study how correlations affect the performance of the simulator of a Maxwell's demon demonstrated in a recent optical experiment [M. D. Vidrighin, O. Dahlsten, M. Barbieri, M. S. Kim, V. Vedral, and I. A. Walmsley, Phys. Rev. Lett. 116, 050401 (2016), 10.1103/PhysRevLett.116.050401]. The power of the demon is found to be enhanced or hindered, depending on the nature of the correlation, in close analogy to the situation faced by a thermal demon.

  15. Spacetimes with Killing tensors. [for Einstein-Maxwell fields with certain spinor indices

    NASA Technical Reports Server (NTRS)

    Hughston, L. P.; Sommers, P.

    1973-01-01

    The characteristics of the Killing equation and the Killing tensor are discussed. A conformal Killing tensor is of interest inasmuch as it gives rise to a quadratic first integral for null geodesic orbits. The Einstein-Maxwell equations are considered together with the Bianchi identity and the conformal Killing tensor. Two examples for the application of the considered relations are presented, giving attention to the charged Kerr solution and the charged C-metric.

  16. A comparison of Fick and Maxwell-Stefan diffusion formulations in PEMFC gas diffusion layers

    NASA Astrophysics Data System (ADS)

    Lindstrom, Michael; Wetton, Brian

    2017-01-01

    This paper explores the mathematical formulations of Fick and Maxwell-Stefan diffusion in the context of polymer electrolyte membrane fuel cell cathode gas diffusion layers. The simple Fick law with a diagonal diffusion matrix is an approximation of Maxwell-Stefan. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. For this application, the formulations can be compared computationally in a simple, one dimensional setting. Despite the models' seemingly different structure, it is observed that the predictions of the formulations are very similar on the cathode when air is used as oxidant. The two formulations give quite different results when the Nitrogen in the air oxidant is replaced by helium (this is often done as a diagnostic for fuel cells designs). The two formulations also give quite different results for the anode with a dilute Hydrogen stream. These results give direction to when Maxwell-Stefan diffusion, which is more complicated to implement computationally in many codes, should be used in fuel cell simulations.

  17. Numerical Simulations of Self-Focused Pulses Using the Nonlinear Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Silberberg, Yaron; Kwak, Dochan (Technical Monitor)

    1994-01-01

    This paper will present results in computational nonlinear optics. An algorithm will be described that solves the full vector nonlinear Maxwell's equations exactly without the approximations that are currently made. Present methods solve a reduced scalar wave equation, namely the nonlinear Schrodinger equation, and neglect the optical carrier. Also, results will be shown of calculations of 2-D electromagnetic nonlinear waves computed by directly integrating in time the nonlinear vector Maxwell's equations. The results will include simulations of 'light bullet' like pulses. Here diffraction and dispersion will be counteracted by nonlinear effects. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit modeling 2-D and 3-D optical soliton propagation, scattering, and switching directly from the full-vector Maxwell's equations. Abstract of a proposed paper for presentation at the meeting NONLINEAR OPTICS: Materials, Fundamentals, and Applications, Hyatt Regency Waikaloa, Waikaloa, Hawaii, July 24-29, 1994, Cosponsored by IEEE/Lasers and Electro-Optics Society and Optical Society of America

  18. Energy/dissipation-preserving Birkhoffian multi-symplectic methods for Maxwell's equations with dissipation terms

    DOE PAGES

    Su, Hongling; Li, Shengtai

    2016-02-03

    In this study, we propose two new energy/dissipation-preserving Birkhoffian multi-symplectic methods (Birkhoffian and Birkhoffian box) for Maxwell's equations with dissipation terms. After investigating the non-autonomous and autonomous Birkhoffian formalism for Maxwell's equations with dissipation terms, we first apply a novel generating functional theory to the non-autonomous Birkhoffian formalism to propose our Birkhoffian scheme, and then implement a central box method to the autonomous Birkhoffian formalism to derive the Birkhoffian box scheme. We have obtained four formal local conservation laws and three formal energy global conservation laws. We have also proved that both of our derived schemes preserve the discrete versionmore » of the global/local conservation laws. Furthermore, the stability, dissipation and dispersion relations are also investigated for the schemes. Theoretical analysis shows that the schemes are unconditionally stable, dissipation-preserving for Maxwell's equations in a perfectly matched layer (PML) medium and have second order accuracy in both time and space. Numerical experiments for problems with exact theoretical results are given to demonstrate that the Birkhoffian multi-symplectic schemes are much more accurate in preserving energy than both the exponential finite-difference time-domain (FDTD) method and traditional Hamiltonian scheme. Finally, we also solve the electromagnetic pulse (EMP) propagation problem and the numerical results show that the Birkhoffian scheme recovers the magnitude of the current source and reaction history very well even after long time propagation.« less

  19. Energy/dissipation-preserving Birkhoffian multi-symplectic methods for Maxwell's equations with dissipation terms

    SciTech Connect

    Su, Hongling; Li, Shengtai

    2016-02-03

    In this study, we propose two new energy/dissipation-preserving Birkhoffian multi-symplectic methods (Birkhoffian and Birkhoffian box) for Maxwell's equations with dissipation terms. After investigating the non-autonomous and autonomous Birkhoffian formalism for Maxwell's equations with dissipation terms, we first apply a novel generating functional theory to the non-autonomous Birkhoffian formalism to propose our Birkhoffian scheme, and then implement a central box method to the autonomous Birkhoffian formalism to derive the Birkhoffian box scheme. We have obtained four formal local conservation laws and three formal energy global conservation laws. We have also proved that both of our derived schemes preserve the discrete version of the global/local conservation laws. Furthermore, the stability, dissipation and dispersion relations are also investigated for the schemes. Theoretical analysis shows that the schemes are unconditionally stable, dissipation-preserving for Maxwell's equations in a perfectly matched layer (PML) medium and have second order accuracy in both time and space. Numerical experiments for problems with exact theoretical results are given to demonstrate that the Birkhoffian multi-symplectic schemes are much more accurate in preserving energy than both the exponential finite-difference time-domain (FDTD) method and traditional Hamiltonian scheme. Finally, we also solve the electromagnetic pulse (EMP) propagation problem and the numerical results show that the Birkhoffian scheme recovers the magnitude of the current source and reaction history very well even after long time propagation.

  20. Higher-derivative gravity with non-minimally coupled Maxwell field

    NASA Astrophysics Data System (ADS)

    Feng, Xing-Hui; Lü, H.

    2016-04-01

    We construct higher-derivative gravities with a non-minimally coupled Maxwell field. The Lagrangian consists of polynomial invariants built from the Riemann tensor and the Maxwell field strength in such a way that the equations of motion are second order for both the metric and the Maxwell potential. We also generalize the construction to involve a generic non-minimally coupled p-form field strength. We then focus on one low-lying example in four dimensions and construct the exact magnetically charged black holes. We also construct exact electrically charged z=2 Lifshitz black holes. We obtain approximate dyonic black holes for the small coupling constant or small charges. We find that the thermodynamics based on the Wald formalism disagrees with that derived from the Euclidean action procedure, suggesting this may be a general situation in higher-derivative gravities with non-minimally coupled form fields. As an application in the AdS/CFT correspondence, we study the entropy/viscosity ratio for the AdS or Lifshitz planar black holes, and find that the exact ratio can be obtained without having to know the details of the solutions, even for this higher-derivative theory.

  1. Reformulation of Maxwell's equations to incorporate near-solute solvent structure.

    PubMed

    Yang, Pei-Kun; Lim, Carmay

    2008-09-04

    Maxwell's equations, which treat electromagnetic interactions between macroscopic charged objects in materials, have explained many phenomena and contributed to many applications in our lives. Derived in 1861 when no methods were available to determine the atomic structure of macromolecules, Maxwell's equations assume the solvent to be a structureless continuum. However, near-solute solvent molecules are highly structured, unlike far-solute bulk solvent molecules. Current methods cannot treat both the near-solute solvent structure and time-dependent electromagnetic interactions in a macroscopic system. Here, we derive "microscopic" electrodynamics equations that can treat macroscopic time-dependent electromagnetic field problems like Maxwell's equations and reproduce the solvent molecular and dipole density distributions observed in molecular dynamics simulations. These equations greatly reduce computational expense by not having to include explicit solvent molecules, yet they treat the solvent electrostatic and van der Waals effects more accurately than continuum models. They provide a foundation to study electromagnetic interactions between molecules in a macroscopic system that are ubiquitous in biology, bioelectromagnetism, and nanotechnology. The general strategy presented herein to incorporate the near-solute solvent structure would enable studies on how complex cellular protein-ligand interactions are affected by electromagnetic radiation, which could help to prevent harmful electromagnetic spectra or find potential therapeutic applications.

  2. High-order nodal discontinuous Galerkin methods for the Maxwell eigenvalue problem.

    PubMed

    Hesthaven, J S; Warburton, T

    2004-03-15

    The Maxwell eigenvalue problem is known to pose difficulties for standard numerical methods, predominantly due to its large null space. As an alternative to the widespread use of Galerkin finite-element methods based on curl-conforming elements, we propose to use high-order nodal elements in a discontinuous element scheme. We consider both two- and three-dimensional problems and show the former to be without problems in a wide range of cases. Numerical experiments suggest the validity of this for general problems. For the three-dimensional eigenproblem, we encounter difficulties with a naive formulation of the scheme and propose minor modifications, intimately related to the discontinuous nature of the formulation, to overcome these concerns. We conclude by connecting the findings to time domain solution of Maxwell's equations. The discussion, analysis, and numerous computational experiments suggest that using discontinuous element schemes for solving Maxwell's equation in the frequency- or time-domain present a high-order accurate, efficient and robust alternative to classical Galerkin finite-element methods.

  3. L2-stability of the Vlasov-Maxwell-Boltzmann system near global Maxwellians

    NASA Astrophysics Data System (ADS)

    Ha, Seung-Yeal; Xiao, Qinghua; Xiong, Linjie; Zhao, Huijiang

    2013-12-01

    We present a L2-stability theory of the Vlasov-Maxwell-Boltzmann system for the two-species collisional plasma. We show that in a perturbative regime of a global Maxwellian, the L2-distance between two strong solutions can be controlled by that between initial data in a Lipschitz manner. Our stability result extends earlier results [Ha, S.-Y. and Xiao, Q.-H., "A revisiting to the L2-stability theory of the Boltzmann equation near global Maxwellians," (submitted) and Ha, S.-Y., Yang, X.-F., and Yun, S.-B., "L2 stability theory of the Boltzmann equation near a global Maxwellian," Arch. Ration. Mech. Anal. 197, 657-688 (2010)] on the L2-stability of the Boltzmann equation to the Boltzmann equation coupled with self-consistent external forces. As a direct application of our stability result, we show that classical solutions in Duan et al. ["Optimal large-time behavior of the Vlasov-Maxwell-Boltzmann system in the whole space," Commun. Pure Appl. Math. 24, 1497-1546 (2011)] and Guo ["The Vlasov-Maxwell-Boltzmann system near Maxwellians," Invent. Math. 153(3), 593-630 (2003)] satisfy a uniform L2-stability estimate. This is the first result on the L2-stability of the Boltzmann equation coupled with self-consistent field equations in three dimensions.

  4. A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer

    NASA Astrophysics Data System (ADS)

    Kadry, Zakaria; Magdy, A. Sirwah; Sameh, A. Alkharashi

    2011-06-01

    Based on a modified-Darcy—Maxwell model, two-dimensional, incompressible and heat transfer flow of two bounded layers, through electrified Maxwell fluids in porous media is performed. The driving force for the instability under an electric field, is an electrostatic force exerted on the free charges accumulated at the dividing interface. Normal mode analysis is considered to study the linear stability of the disturbances layers. The solutions of the linearized equations of motion with the boundary conditions lead to an implicit dispersion relation between the growth rate and wave number. These equations are parameterized by Weber number, Reynolds number, Marangoni number, dimensionless conductivities, and dimensionless electric potentials. The case of long waves interfacial stability has been studied. The stability criteria are performed theoretically in which stability diagrams are obtained. In the limiting cases, some previously published results can be considered as particular cases of our results. It is found that the Reynolds number plays a destabilizing role in the stability criteria, while the damping influence is observed for the increasing of Marangoni number and Maxwell relaxation time.

  5. Relativistic version of the Feynman-Dyson-Hughes derivation of the Lorentz force law and Maxwell's homogeneous equations

    NASA Astrophysics Data System (ADS)

    Essén, Hanno; Nordmark, Arne B.

    2016-09-01

    The canonical Poisson bracket algebra of four-dimensional relativistic mechanics is used to derive the equation of motion for a charged particle, with the Lorentz force, and the homogeneous Maxwell equations.

  6. Direct time integration of Maxwell's equations in nonlinear dispersive media for propagation and scattering of femtosecond electromagnetic solitons

    NASA Technical Reports Server (NTRS)

    Goorjian, Peter M.; Taflove, Allen

    1992-01-01

    The initial results for femtosecond electromagnetic soliton propagation and collision obtained from first principles, i.e., by a direct time integration of Maxwell's equations are reported. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization and can take into account such quantum effects as Kerr and Raman interactions. The present approach is robust and should permit the modeling of 2D and 3D optical soliton propagation, scattering, and switching from the full-vector Maxwell's equations.

  7. Statistical Neurodynamics.

    NASA Astrophysics Data System (ADS)

    Paine, Gregory Harold

    1982-03-01

    The primary objective of the thesis is to explore the dynamical properties of small nerve networks by means of the methods of statistical mechanics. To this end, a general formalism is developed and applied to elementary groupings of model neurons which are driven by either constant (steady state) or nonconstant (nonsteady state) forces. Neuronal models described by a system of coupled, nonlinear, first-order, ordinary differential equations are considered. A linearized form of the neuronal equations is studied in detail. A Lagrange function corresponding to the linear neural network is constructed which, through a Legendre transformation, provides a constant of motion. By invoking the Maximum-Entropy Principle with the single integral of motion as a constraint, a probability distribution function for the network in a steady state can be obtained. The formalism is implemented for some simple networks driven by a constant force; accordingly, the analysis focuses on a study of fluctuations about the steady state. In particular, a network composed of N noninteracting neurons, termed Free Thinkers, is considered in detail, with a view to interpretation and numerical estimation of the Lagrange multiplier corresponding to the constant of motion. As an archetypical example of a net of interacting neurons, the classical neural oscillator, consisting of two mutually inhibitory neurons, is investigated. It is further shown that in the case of a network driven by a nonconstant force, the Maximum-Entropy Principle can be applied to determine a probability distribution functional describing the network in a nonsteady state. The above examples are reconsidered with nonconstant driving forces which produce small deviations from the steady state. Numerical studies are performed on simplified models of two physical systems: the starfish central nervous system and the mammalian olfactory bulb. Discussions are given as to how statistical neurodynamics can be used to gain a better

  8. Stupid statistics!

    PubMed

    Tellinghuisen, Joel

    2008-01-01

    The method of least squares is probably the most powerful data analysis tool available to scientists. Toward a fuller appreciation of that power, this work begins with an elementary review of statistics fundamentals, and then progressively increases in sophistication as the coverage is extended to the theory and practice of linear and nonlinear least squares. The results are illustrated in application to data analysis problems important in the life sciences. The review of fundamentals includes the role of sampling and its connection to probability distributions, the Central Limit Theorem, and the importance of finite variance. Linear least squares are presented using matrix notation, and the significance of the key probability distributions-Gaussian, chi-square, and t-is illustrated with Monte Carlo calculations. The meaning of correlation is discussed, including its role in the propagation of error. When the data themselves are correlated, special methods are needed for the fitting, as they are also when fitting with constraints. Nonlinear fitting gives rise to nonnormal parameter distributions, but the 10% Rule of Thumb suggests that such problems will be insignificant when the parameter is sufficiently well determined. Illustrations include calibration with linear and nonlinear response functions, the dangers inherent in fitting inverted data (e.g., Lineweaver-Burk equation), an analysis of the reliability of the van't Hoff analysis, the problem of correlated data in the Guggenheim method, and the optimization of isothermal titration calorimetry procedures using the variance-covariance matrix for experiment design. The work concludes with illustrations on assessing and presenting results.

  9. L{sup 2}-stability of the Vlasov-Maxwell-Boltzmann system near global Maxwellians

    SciTech Connect

    Ha, Seung-Yeal Xiao, Qinghua; Xiong, Linjie Zhao, Huijiang

    2013-12-15

    We present a L{sup 2}-stability theory of the Vlasov-Maxwell-Boltzmann system for the two-species collisional plasma. We show that in a perturbative regime of a global Maxwellian, the L{sup 2}-distance between two strong solutions can be controlled by that between initial data in a Lipschitz manner. Our stability result extends earlier results [Ha, S.-Y. and Xiao, Q.-H., “A revisiting to the L{sup 2}-stability theory of the Boltzmann equation near global Maxwellians,” (submitted) and Ha, S.-Y., Yang, X.-F., and Yun, S.-B., “L{sup 2} stability theory of the Boltzmann equation near a global Maxwellian,” Arch. Ration. Mech. Anal. 197, 657–688 (2010)] on the L{sup 2}-stability of the Boltzmann equation to the Boltzmann equation coupled with self-consistent external forces. As a direct application of our stability result, we show that classical solutions in Duan et al. [“Optimal large-time behavior of the Vlasov-Maxwell-Boltzmann system in the whole space,” Commun. Pure Appl. Math. 24, 1497–1546 (2011)] and Guo [“The Vlasov-Maxwell-Boltzmann system near Maxwellians,” Invent. Math. 153(3), 593–630 (2003)] satisfy a uniform L{sup 2}-stability estimate. This is the first result on the L{sup 2}-stability of the Boltzmann equation coupled with self-consistent field equations in three dimensions.

  10. Using quantum erasure to exorcize Maxwell's demon: I. Concepts and context

    NASA Astrophysics Data System (ADS)

    Scully, Marlan O.; Rostovtsev, Yuri; Sariyanni, Zoe-Elizabeth; Suhail Zubairy, M.

    2005-10-01

    Szilard [L. Szilard, Zeitschrift für Physik, 53 (1929) 840] made a decisive step toward solving the Maxwell demon problem by introducing and analyzing the single atom heat engine. Bennett [Sci. Am. 255 (1987) 107] completed the solution by pointing out that there must be an entropy, ΔS=kln2, generated as the result of information erased on each cycle. Nevertheless, others have disagreed. For example, philosophers such as Popper “have found the literature surrounding Maxwell's demon deeply problematic.” We propose and analyze a new kind of single atom quantum heat engine which allows us to resolve the Maxwell demon paradox simply, and without invoking the notions of information or entropy. The energy source of the present quantum engine [Scully, Phys. Rev. Lett. 87 (2001) 22601] is a Stern-Gerlach apparatus acting as a demonesque heat sorter. An isothermal compressor acts as the entropy sink. In order to complete a thermodynamic cycle, an energy of ΔW=kTln2 must be expended. This energy is essentially a “reset” or “eraser” energy. Thus Bennett's entropy ΔS=ΔW/T emerges as a simple consequence of the quantum thermodynamics of our heat engine. It would seem that quantum mechanics contains the kernel of information entropy at its very core. That is the concept of information erasure as it appears in quantum mechanics [Scully and Drühl, Phys. Rev. A 25 (1982) 2208] and the present quantum heat engine have a deep common origin.

  11. Rigorous simulation of OCT image formation using Maxwell's equations in three dimensions (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Munro, Peter R. T.; Curatolo, Andrea; Sampson, David D.

    2016-03-01

    Existing models of image formation in optical coherence tomography are based upon the extended Huygens-Fresnel formalism. These models all, to varying degrees, rely on scatterer ensemble averages, rather than deterministic scattering distributions. Whilst the former is sometimes preferable, there are a growing number of applications where the ability to predict image formation based upon deterministic refractive index distributions is of great interest, including, for example, image formation in turbid tissue. A rigorous model based upon three-dimensional solutions of Maxwell's equations offers a number of tantalising opportunities. For example, shedding light on features near or below the resolution of an OCT system and on the impact of phenomena usually described as diffraction, interference and scattering, but which more generally result from light scattering satisfying Maxwell's equations. A rigorous model allows inverse scattering methods to be developed not requiring the first-order Born approximation. Finally, a rigorous model can provide gold standard verification of myriad quantitative techniques currently being developed throughout the field. We have developed the first such model of image formation based upon three-dimensional solutions of Maxwell's equations, which has vastly different properties to models based on two-dimensional solutions. Although we present simulated B-scans, this model is equally applicable to C-scans. This has been made possible by advances in computational techniques and in computational resources routinely available. We will present the main features of our model, comparisons of measured and simulated image formation for phantoms and discuss the future of rigorous modelling in optical coherence tomography research and application.

  12. The free-electron laser - Maxwell's equations driven by single-particle currents

    NASA Technical Reports Server (NTRS)

    Colson, W. B.; Ride, S. K.

    1980-01-01

    It is shown that if single particle currents are coupled to Maxwell's equations, the resulting set of self-consistent nonlinear equations describes the evolution of the electron beam and the amplitude and phase of the free-electron-laser field. The formulation is based on the slowly varying amplitude and phase approximation, and the distinction between microscopic and macroscopic scales, which distinguishes the microscopic bunching from the macroscopic pulse propagation. The capabilities of this new theoretical approach become apparent when its predictions for the ultrashort pulse free-electron laser are compared to experimental data; the optical pulse evolution, determined simply and accurately, agrees well with observations.

  13. Mass, angular momentum, and charge inequalities for black holes in Einstein-Maxwell-axion-dilaton gravity

    NASA Astrophysics Data System (ADS)

    Rogatko, Marek

    2014-02-01

    Mass, angular momentum, and charge inequalities for axisymmetric maximal time-symmetric initial data invariant under an action of U(1) group, in Einstein-Maxwell-axion-dilaton gravity being the low-energy limit of the heterotic string theory, is established. We assume that a data set with two asymptotically flat regions is given on a smooth simply connected manifold. We also pay attention to the area momentum charge inequalities for a closed orientable two-dimensional spacelike surface embedded in the spacetime of the considered theory.

  14. Superradiance of a charged scalar field coupled to the Einstein-Maxwell equations

    NASA Astrophysics Data System (ADS)

    Baake, Olaf; Rinne, Oliver

    2016-12-01

    We consider the Einstein-Maxwell-Klein-Gordon equations for a spherically symmetric scalar field scattering off a Reissner-Nordström black hole in asymptotically flat spacetime. The equations are solved numerically using a hyperboloidal evolution scheme. For suitable frequencies of the initial data, superradiance is observed, leading to a substantial decrease of mass and charge of the black hole. We also derive a Bondi mass loss formula using the Kodama vector field and investigate the late-time decay of the scalar field.

  15. A Fourier collocation time domain method for numerically solving Maxwell's equations

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1991-01-01

    A new method for solving Maxwell's equations in the time domain for arbitrary values of permittivity, conductivity, and permeability is presented. Spatial derivatives are found by a Fourier transform method and time integration is performed using a second order, semi-implicit procedure. Electric and magnetic fields are collocated on the same grid points, rather than on interleaved points, as in the Finite Difference Time Domain (FDTD) method. Numerical results are presented for the propagation of a 2-D Transverse Electromagnetic (TEM) mode out of a parallel plate waveguide and into a dielectric and conducting medium.

  16. The Singularity Mystery Associated with a Radially Continuous Maxwell Viscoelastic Structure

    NASA Technical Reports Server (NTRS)

    Fang, Ming; Hager, Bradford H.

    1995-01-01

    The singularity problem associated with a radially continuous Maxwell viscoclastic structure is investigated. A special tool called the isolation function is developed. Results calculated using the isolation function show that the discrete model assumption is no longer valid when the viscoelastic parameter becomes a continuous function of radius. Continuous variations in the upper mantle viscoelastic parameter are especially powerful in destroying the mode-like structures. The contribution to the load Love numbers of the singularities is sensitive to the convexity of the viscoelastic parameter models. The difference between the vertical response and the horizontal response found in layered viscoelastic parameter models remains with continuous models.

  17. Visible and hidden sectors in a model with Maxwell and Chern-Simons gauge dynamics

    NASA Astrophysics Data System (ADS)

    Ireson, Edwin; Schaposnik, Fidel A.; Tallarita, Gianni

    2016-11-01

    We study a U(1) × U(1) gauge theory discussing its vortex solutions and supersymmetric extension. In our set-up, the dynamics of one of two Abelian gauge fields is governed by a Maxwell term, the other by a Chern-Simons term. The two sectors interact via a BF gauge field mixing and a Higgs portal term that connects the two complex scalars. We also consider the supersymmetric version of this system which allows to find for the bosonic sector BPS equations in which an additional real scalar field enters into play. We study numerically the field equations finding vortex solutions with both magnetic flux and electric charge.

  18. Divergence preserving discrete surface integral methods for Maxwell's curl equations using non-orthogonal unstructured grids

    NASA Technical Reports Server (NTRS)

    Madsen, Niel K.

    1992-01-01

    Several new discrete surface integral (DSI) methods for solving Maxwell's equations in the time-domain are presented. These methods, which allow the use of general nonorthogonal mixed-polyhedral unstructured grids, are direct generalizations of the canonical staggered-grid finite difference method. These methods are conservative in that they locally preserve divergence or charge. Employing mixed polyhedral cells, (hexahedral, tetrahedral, etc.) these methods allow more accurate modeling of non-rectangular structures and objects because the traditional stair-stepped boundary approximations associated with the orthogonal grid based finite difference methods can be avoided. Numerical results demonstrating the accuracy of these new methods are presented.

  19. Proposal for detection of QED vacuum nonlinearities in Maxwell's equations by the use of waveguides.

    PubMed

    Brodin, G; Marklund, M; Stenflo, L

    2001-10-22

    We present a novel method for detecting nonlinearities, due to quantum electrodynamics through photon-photon scattering, in Maxwell's equation. The photon-photon scattering gives rise to self-interaction terms which are similar to the nonlinearities due to the polarization in nonlinear optics. These self-interaction terms vanish in the limit of parallel propagating waves, but if, instead of parallel propagating waves, the modes generated in waveguides are used, there will be a nonzero total effect. Based on this idea, we calculate the nonlinear excitation of new modes and estimate the strength of this effect. Furthermore, we suggest a principal experimental setup.

  20. Viscoelastic creep and relaxation of dielectric elastomers characterized by a Kelvin-Voigt-Maxwell model

    NASA Astrophysics Data System (ADS)

    Zhang, Junshi; Ru, Jie; Chen, Hualing; Li, Dichen; Lu, Jian

    2017-01-01

    For dielectric elastomers (DEs), the inherent viscoelasticity leads to a time-dependent deformation during actuation. To describe such a viscoelastic behavior, a constitutive model is developed by utilizing a combined Kelvin-Voigt-Maxwell (KVM) model. The established model captures both the initial jumping deformation and the following slow creeping. Subsequently, with an employment of VHB 4910 elastomer, experiments are performed to validate the viscoelastic KVM model. The results indicate a good agreement between the simulation and experimental data. Effect of the parameters in KVM model on the viscoelastic deformation of DEs is also investigated.

  1. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    SciTech Connect

    Lindsey, C.A.; Yee, S.; Roellig, T.L.; Hills, R.; Brock, D. NASA, Ames Research Center, Moffett Field, CA Mullard Radio Astronomy Observatory, Cambridge Joint Astronomy Centre, Hilo, HI )

    1990-04-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun. 7 refs.

  2. Submillimeter observations of the sun from the James Clerk Maxwell Telescope

    NASA Technical Reports Server (NTRS)

    Lindsey, Charles A.; Yee, Selwyn; Roellig, Thomas L.; Hills, Richard; Brock, David

    1990-01-01

    The first submillimeter solar observations from the 15 m James Clerk Maxwell Telescope (JCMT) on Mauna Kea are reported. The JCMT submillimeter heterodyne receiver is used to observe the sun in 850 micron radiation. These are the first submillimeter observations of features on the size scale of the chromospheric supergranular network and of sunspots. A comparison is made between 850 micron images and calcium K line images of the chromospheric supergranular network in the quiet sun and in plage. Images of sunspots are given, noting that their 850 micron brightness is comparable to, or somewhat greater than, that of the quiet sun.

  3. First Order Solutions for Klein-Gordon-Maxwell Equations in a Specific Curved Manifold Case

    SciTech Connect

    Murariu, Gabriel

    2009-05-22

    The aim of this paper is to study the SO(3,1)xU(1) gauge minimally coupled charged spinless field to a spherically symmetric curved space-time. It is derived the first order analytically approximation solution for the system of Klein-Gordon-Maxwell equations. Using these solutions, it evaluated the system electric charge density. The considered space -time manifold generalize an anterior studied one. The chosen space time configuration is of S diagonal type from the MAPLE GRTensor II metrics package.

  4. Exact Solutions to the Einstein-Maxwell Equations Describing Wormholes and Handles

    NASA Astrophysics Data System (ADS)

    Khlestkov, Yu. A.; Sukhanova, L. A.

    2016-06-01

    On the basis of the exact solutions to the non-stationary spherically symmetric Einstein and Maxwell equations for dust matter and radial electromagnetic field, a model of a wormhole with the pulsating in time inner world and two static throats has been developed. It has been shown that such a wormhole with an arbitrary radius of the Gaussian curvature can connect both two different asymptotically flat space-times and two regions of the selfsame space-time (handles of the Wheeler type). The problem of the fulfilment of the energy conditions in this wormhole has been investigated, as well as the problem of its traversability investigation has been set.

  5. Plane surface suddenly set in motion in a viscoelastic fluid with fractional Maxwell model

    NASA Astrophysics Data System (ADS)

    Wenchang, Tan; Mingyu, Xu

    2002-08-01

    The fractional calculus approach in the constitutive relationship model of viscoelastic fluid is introduced. The flow near a wall suddenly set in motion is studied for a non-Newtonian viscoelastic fluid with the fractional Maxwell model. Exact solutions of velocity and stress are obtained by using the discrete inverse Laplace transform of the sequential fractional derivatives. It is found that the effect of the fractional orders in the constitutive relationship on the flow field is significant. The results show that for small times there are appreciable viscoelastic effects on the shear stress at the plate, for large times the viscoelastic effects become weak.

  6. Metamaterial-based half Maxwell fish-eye lens for broadband directive emissions

    NASA Astrophysics Data System (ADS)

    Dhouibi, Abdallah; Nawaz Burokur, Shah; de Lustrac, André; Priou, Alain

    2013-01-01

    The broadband directive emission from a metamaterial surface is numerically and experimentally reported. The metasurface, composed of non-resonant complementary closed ring structures, is designed to obey the refractive index of a half Maxwell fish-eye lens. A planar microstrip Vivaldi antenna is used as transverse magnetic polarized wave launcher for the lens. A prototype of the lens associated with its feed structure has been fabricated using standard lithography techniques. To experimentally demonstrate the broadband focusing properties and directive emissions, both the far-field radiation patterns and the near-field distributions have been measured. Measurements agree quantitatively and qualitatively with theoretical simulations.

  7. Simple model for transport phenomena: microscopic construction of Maxwell demonlike engine.

    PubMed

    Chaudhuri, Jyotipratim Ray; Chattopadhyay, Sudip; Banik, Suman Kumar

    2007-12-14

    We present a microscopic Hamiltonian framework to develop Maxwell demonlike engine. Our model consists of an equilibrium thermal bath and a nonequilibrium bath, latter generated by driving with an external stationary, Gaussian noise. The engine we develop can be considered as a device to extract work by modifying internal fluctuations. Our theoretical analysis focuses on finding the essential ingredients necessary for generating fluctuation induced transport under nonequilibrium condition. An important outcome of our model is that the net motion occurs when the nonlinear bath is modulated by the external noise, creating the nonzero effective temperature even when the temperature of both the baths are the same.

  8. The Einstein-Maxwell-aether-axion theory: Dynamo-optical anomaly in the electromagnetic response

    NASA Astrophysics Data System (ADS)

    Alpin, Timur Yu.; Balakin, Alexander B.

    2016-03-01

    We consider a pp-wave symmetric model in the framework of the Einstein-Maxwell-aether-axion theory. Exact solutions to the equations of axion electrodynamics are obtained for the model, in which pseudoscalar, electric and magnetic fields were constant before the arrival of a gravitational pp-wave. We show that dynamo-optical interactions, i.e. couplings of electromagnetic field to a dynamic unit vector field, attributed to the velocity of a cosmic substratum (aether, vacuum, dark fluid…), provide the response of axionically active electrodynamic system to display anomalous behavior.

  9. A Spectral Algorithm for Solving the Relativistic Vlasov-Maxwell Equations

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    2001-01-01

    A spectral method algorithm is developed for the numerical solution of the full six-dimensional Vlasov-Maxwell system of equations. Here, the focus is on the electron distribution function, with positive ions providing a constant background. The algorithm consists of a Jacobi polynomial-spherical harmonic formulation in velocity space and a trigonometric formulation in position space. A transform procedure is used to evaluate nonlinear terms. The algorithm is suitable for performing moderate resolution simulations on currently available supercomputers for both scientific and engineering applications.

  10. The Hamiltonian Structure and Euler-Poincare Formulation of the Valsov-Maxwell and Gyrokinetic System

    SciTech Connect

    J. Squire, H. Qin and W.M. Tang

    2012-09-25

    We present a new variational principle for the gyrokinetic system, similar to the Maxwell-Vlasov action presented in Ref. 1. The variational principle is in the Eulerian frame and based on constrained variations of the phase space fluid velocity and particle distribution function. Using a Legendre transform, we explicitly derive the field theoretic Hamiltonian structure of the system. This is carried out with the Dirac theory of constraints, which is used to construct meaningful brackets from those obtained directly from Euler-Poincare theory. Possible applications of these formulations include continuum geometric integration techniques, large-eddy simulation models and Casimir type stability methods. __________________________________________________

  11. Sakiadis flow of Maxwell fluid considering magnetic field and convective boundary conditions

    SciTech Connect

    Mustafa, M.; Khan, Junaid Ahmad; Hayat, T.; Alsaedi, A.

    2015-02-15

    In this paper we address the flow of Maxwell fluid due to constantly moving flat radiative surface with convective condition. The flow is under the influence of non-uniform transverse magnetic field. The velocity and temperature distributions have been evaluated numerically by shooting approach. The solution depends on various interesting parameters including local Deborah number De, magnetic field parameter M, Prandtl number Pr and Biot number Bi. We found that variation in velocity with an increase in local Deborah number De is non-monotonic. However temperature is a decreasing function of local Deborah number De.

  12. Second order finite volume scheme for Maxwell's equations with discontinuous electromagnetic properties on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Ismagilov, Timur Z.

    2015-02-01

    This paper presents a second order finite volume scheme for numerical solution of Maxwell's equations with discontinuous dielectric permittivity and magnetic permeability on unstructured meshes. The scheme is based on Godunov scheme and employs approaches of Van Leer and Lax-Wendroff to increase the order of approximation. To keep the second order of approximation near dielectric permittivity and magnetic permeability discontinuities a novel technique for gradient calculation and limitation is applied near discontinuities. Results of test computations for problems with linear and curvilinear discontinuities confirm second order of approximation. The scheme was applied to modelling propagation of electromagnetic waves inside photonic crystal waveguides with a bend.

  13. On-Chip Maxwell's Demon as an Information-Powered Refrigerator

    NASA Astrophysics Data System (ADS)

    Koski, J. V.; Kutvonen, A.; Khaymovich, I. M.; Ala-Nissila, T.; Pekola, J. P.

    2015-12-01

    We present an experimental realization of an autonomous Maxwell's demon, which extracts microscopic information from a system and reduces its entropy by applying feedback. It is based on two capacitively coupled single-electron devices, both integrated on the same electronic circuit. This setup allows a detailed analysis of the thermodynamics of both the demon and the system as well as their mutual information exchange. The operation of the demon is directly observed as a temperature drop in the system. We also observe a simultaneous temperature rise in the demon arising from the thermodynamic cost of generating the mutual information.

  14. Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme

    NASA Astrophysics Data System (ADS)

    Squire, Jonathan; Qin, Hong; Tang, William

    2012-10-01

    A fully variational, unstructured, electromagnetic particle-in-cell integrator is developed for integration of the Vlasov-Maxwell equations. Using the formalism of Discrete Exterior Calculus [1], the field solver, interpolation scheme and particle advance algorithm are derived through minimization of a single discrete field theory action. As a consequence of ensuring that the action is invariant under discrete electromagnetic gauge transformations, the integrator exactly conserves Gauss's law. This work was supported by USDOE Contract DE-AC02-09CH11466.[4pt] [1] M. Desbrun, A. N. Hirani, M. Leok, and J. E. Marsden, (2005), arXiv:math/0508341

  15. Quantization of the Maxwell fish-eye problem and the quantum-classical correspondence

    SciTech Connect

    Makowski, A. J.; Gorska, K. J.

    2009-05-15

    The so-called fish-eye model, originally investigated by Maxwell in geometrical optics, is studied both in the classical as well as in the quantum formulations. The best agreement between the two approaches is achieved by using a suitably constructed coherent state, which is of the SU(2) type. The perfect quantum-classical correspondence is obtained in the sense that classical rays go exactly over maxima of the corresponding quantum probability distributions. The distributions are made of linear combinations of the E=0 bound states of the considered model.

  16. Gauge invariances of higher derivative Maxwell-Chern-Simons field theory: A new Hamiltonian approach

    NASA Astrophysics Data System (ADS)

    Mukherjee, Pradip; Paul, Biswajit

    2012-02-01

    A new method of abstracting the independent gauge invariances of higher derivative systems, recently introduced in [R. Banerjee, P. Mukherjee, and B. Paul, J. High Energy Phys.JHEPFG1029-8479 08 (2011) 085.10.1007/JHEP08(2011)085], has been applied to higher derivative field theories. This has been discussed taking the extended Maxwell-Chern-Simons model as an example. A new Hamiltonian analysis of the model is provided. This Hamiltonian analysis has been used to construct the independent gauge generator. An exact mapping between the Hamiltonian gauge transformations and the U(1) symmetries of the action has been established.

  17. First integrals of motion in a gauge covariant framework, Killing-Maxwell system and quantum anomalies

    SciTech Connect

    Visinescu, M.

    2012-10-15

    Hidden symmetries in a covariant Hamiltonian framework are investigated. The special role of the Stackel-Killing and Killing-Yano tensors is pointed out. The covariant phase-space is extended to include external gauge fields and scalar potentials. We investigate the possibility for a higher-order symmetry to survive when the electromagnetic interactions are taken into account. Aconcrete realization of this possibility is given by the Killing-Maxwell system. The classical conserved quantities do not generally transfer to the quantized systems producing quantum gravitational anomalies. As a rule the conformal extension of the Killing vectors and tensors does not produce symmetry operators for the Klein-Gordon operator.

  18. The Vlasov-Maxwell-Boltzmann System Near Maxwellians in the Whole Space with Very Soft Potentials

    NASA Astrophysics Data System (ADS)

    Duan, Renjun; Lei, Yuanjie; Yang, Tong; Zhao, Huijiang

    2017-04-01

    Since the work by Guo (Invent Math 153(3):593-630, 2003), it has remained an open problem to establish the global existence of perturbative classical solutions around a global Maxwellian to the Vlasov-Maxwell-Boltzmann system with the whole range of soft potentials. This is mainly due to the complex structure of the system, in particular, the degenerate dissipation at large velocity, the velocity-growth of the nonlinear term induced by the Lorentz force, and the regularity-loss of the electromagnetic fields. This paper solves this problem in the whole space provided that initial perturbation has sufficient regularity and velocity-integrability.

  19. Plastic Surgery Statistics

    MedlinePlus

    ... PRS GO PSN PSEN GRAFT Contact Us News Plastic Surgery Statistics Plastic surgery procedural statistics from the ... Plastic Surgery Statistics 2005 Plastic Surgery Statistics 2016 Plastic Surgery Statistics Stats Report 2016 National Clearinghouse of ...

  20. Thermal equilibrium and statistical thermometers in special relativity.

    PubMed

    Cubero, David; Casado-Pascual, Jesús; Dunkel, Jörn; Talkner, Peter; Hänggi, Peter

    2007-10-26

    There is an intense debate in the recent literature about the correct generalization of Maxwell's velocity distribution in special relativity. The most frequently discussed candidate distributions include the Jüttner function as well as modifications thereof. Here we report results from fully relativistic one-dimensional molecular dynamics simulations that resolve the ambiguity. The numerical evidence unequivocally favors the Jüttner distribution. Moreover, our simulations illustrate that the concept of "thermal equilibrium" extends naturally to special relativity only if a many-particle system is spatially confined. They make evident that "temperature" can be statistically defined and measured in an observer frame independent way.

  1. Quantum-statistical equilibrium and the ``law'' of constant Fermi potential

    NASA Astrophysics Data System (ADS)

    Le Coz, Yannick L.

    2003-02-01

    We apply the general quantum-statistical density-matrix formalism to an independent-electron gas within a space-dependent external electric potential, under equilibrium conditions. This problem is analogous to an ideal semiconductor homojunction diode. We solve the resulting equilibrium density-matrix equation using a perturbation theory. Next, we derive a first-order quantum correction to the classical Maxwell-Boltzmann density-potential formula. The correction appears as an added curvature term in external potential. It represents expected quantum-mechanical scattering against a spatially varying potential. Our results indicate that the commonly encountered thermodynamic or statistical-mechanical "law" of constant, equilibrium Fermi potential—with Fermi potential a parameter in the Maxwell-Boltzmann density-potential formula—is not fundamentally exact. In a general space-dependent potential, this "law," we prove, is simply a classical approximation.

  2. Development of an explicit non-staggered scheme for solving three-dimensional Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Sheu, Tony W. H.; Chung, Y. W.; Li, J. H.; Wang, Y. C.

    2016-10-01

    An explicit finite-difference scheme for solving the three-dimensional Maxwell's equations in non-staggered grids is presented. We aspire to obtain time-dependent solutions of the Faraday's and Ampère's equations and predict the electric and magnetic fields within the discrete zero-divergence context (or Gauss's law). The local conservation laws in Maxwell's equations are numerically preserved using the explicit second-order accurate symplectic partitioned Runge-Kutta temporal scheme. Following the method of lines, the spatial derivative terms in the semi-discretized Faraday's and Ampère's equations are approximated theoretically to obtain a highly accurate numerical phase velocity. The proposed fourth-order accurate space-centered finite difference scheme minimizes the discrepancy between the exact and numerical phase velocities. This minimization process considerably reduces the dispersion and anisotropy errors normally associated with finite difference time-domain methods. The computational efficiency of getting the same level of accuracy at less computing time and the ability of preserving the symplectic property have been numerically demonstrated through several test problems.

  3. Energy-conserving discontinuous Galerkin methods for the Vlasov-Maxwell system

    NASA Astrophysics Data System (ADS)

    Cheng, Yingda; Christlieb, Andrew J.; Zhong, Xinghui

    2014-12-01

    In this paper, we generalize the idea in our previous work for the Vlasov-Ampère (VA) system (Y. Cheng, A.J. Christlieb, and X. Zhong (2014) [10]) and develop energy-conserving discontinuous Galerkin (DG) methods for the Vlasov-Maxwell (VM) system. The VM system is a fundamental model in the simulation of collisionless magnetized plasmas. Compared to Y. Cheng, A.J. Christlieb, and X. Zhong (2014) [10], additional care needs to be taken for both the temporal and spatial discretizations to achieve similar type of conservation when the magnetic field is no longer negligible. Our proposed schemes conserve the total particle number and the total energy at the same time, therefore can obtain accurate and physically relevant numerical solutions. The main components of our methods include second order and above, explicit or implicit energy-conserving temporal discretizations, and DG methods for Vlasov and Maxwell's equations with carefully chosen numerical fluxes. Benchmark numerical tests such as the streaming Weibel instability are provided to validate the accuracy and conservation of the schemes.

  4. Maxwell and very-hard-particle models for probabilistic ballistic annihilation: Hydrodynamic description

    NASA Astrophysics Data System (ADS)

    Coppex, François; Droz, Michel; Trizac, Emmanuel

    2005-08-01

    The hydrodynamic description of probabilistic ballistic annihilation, for which no conservation laws hold, is an intricate problem with hard spherelike dynamics for which no exact solution exists. We consequently focus on simplified approaches, the Maxwell and very-hard-particle (VHP) models, which allows us to compute analytically upper and lower bounds for several quantities. The purpose is to test the possibility of describing such a far from equilibrium dynamics with simplified kinetic models. The motivation is also in turn to assess the relevance of some singular features appearing within the original model and the approximations invoked to study it. The scaling exponents are first obtained from the (simplified) Boltzmann equation, and are confronted against direct Monte Carlo simulations. Then, the Chapman-Enskog method is used to obtain constitutive relations and transport coefficients. The corresponding Navier-Stokes equations for the hydrodynamic fields are derived for both Maxwell and VHP models. We finally perform a linear stability analysis around the homogeneous solution, which illustrates the importance of dissipation in the possible development of spatial inhomogeneities.

  5. Comparisons of the Maxwell and CLL gas/surface interaction models using DSMC

    NASA Technical Reports Server (NTRS)

    Hedahl, Marc O.; Wilmoth, Richard G.

    1995-01-01

    The behavior of two different models of gas-surface interactions is studied using the Direct Simulation Monte Carlo (DSMC) method. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between the Maxwell and the Cercignani-Lampis-Lord (CLL) models for flat plate configurations at freestream conditions corresponding to a 140 km orbit around Venus. The size of the flat plate represents one of the solar panels on the Magellan spacecraft, and the freestream conditions correspond to those experienced during aerobraking maneuvers. Results are presented for both a single flat plate and a two-plate configuration as a function of angle of attack and gas-surface accommodation coefficients. The two-plate system is not representative of the Magellan geometry but is studied to explore possible experiments that might be used to differentiate between the two gas-surface interaction models. The Maxwell and CLL models produce qualitatively similar results for the aerodynamic forces and heat transfer on a single flat plate. However, the flow fields produced with the two models are qualitatively different for both the single-plate and two-plate calculations. These differences in the flowfield lead to predictions of the angle of attack for maximum heat transfer in a two plate configuration that are distinctly different for the two gas-surface interactions models.

  6. Vector dark energy models with quadratic terms in the Maxwell tensor derivatives

    NASA Astrophysics Data System (ADS)

    Haghani, Zahra; Harko, Tiberiu; Sepangi, Hamid Reza; Shahidi, Shahab

    2017-03-01

    We consider a vector-tensor gravitational model with terms quadratic in the Maxwell tensor derivatives, called the Bopp-Podolsky term. The gravitational field equations of the model and the equations describing the evolution of the vector field are obtained and their Newtonian limit is investigated. The cosmological implications of a Bopp-Podolsky type dark energy term are investigated for a Bianchi type I homogeneous and anisotropic geometry for two models, corresponding to the absence and presence of the self-interacting potential of the field, respectively. The time evolutions of the Hubble function, of the matter energy density, of the shear scalar, of the mean anisotropy parameter, and of the deceleration parameter, respectively, as well as the field potentials are obtained for both cases by numerically integrating the cosmological evolution equations. In the presence of the vector type dark energy with quadratic terms in the Maxwell tensor derivatives, depending on the numerical values of the model parameters, the Bianchi type I Universe experiences a complex dynamical evolution, with the dust Universes ending in an isotropic phase. The presence of the self-interacting potential of the vector field significantly shortens the time interval necessary for the full isotropization of the Universe.

  7. A multilevel local discrete convolution method for the numerical solution for Maxwell's Equations

    NASA Astrophysics Data System (ADS)

    Lo, Boris; Colella, Phillip

    2016-10-01

    We present a new discrete multilevel local discrete convolution method for solving Maxwell's equations in three dimensions. We obtain an explicit real-space representation for the propagator of an auxiliary system of differential equations with initial value constraints that is equivalent to Maxwell's equations. The propagator preserves finite speed of propagation and source locality. Because the propagator involves convolution against a singular distribution, we regularize via convolution with smoothing kernels (B-splines) prior to sampling. We have shown that the ultimate discrete convolutional propagator can be constructed to attain an arbitrarily high order of accuracy by using higher-order regularizing kernels and finite difference stencils. The discretized propagator is compactly supported and can be applied using Hockney's method (1970) and parallelized using domain decomposition, leading to a method that is computationally efficient. The algorithm is extended to work for locally refined fixed hierarchy of rectangular grids. This research is supported by the Office of Advanced Scientific Computing Research of the US Department of Energy under Contract Number DE-AC02-05CH11231.

  8. Fractional Generalizations of Maxwell and Kelvin-Voigt Models for Biopolymer Characterization

    PubMed Central

    Jóźwiak, Bertrand; Orczykowska, Magdalena; Dziubiński, Marek

    2015-01-01

    The paper proposes a fractional generalization of the Maxwell and Kelvin-Voigt rheological models for a description of dynamic behavior of biopolymer materials. It was found that the rheological models of Maxwell-type do not work in the case of modeling of viscoelastic solids, and the model which significantly better describes the nature of changes in rheological properties of such media is the modified fractional Kelvin-Voigt model with two built-in springpots (MFKVM2). The proposed model was used to describe the experimental data from the oscillatory and creep tests of 3% (w/v) kuzu starch pastes, and to determine the values of their rheological parameters as a function of pasting time. These parameters provide a lot of additional information about structure and viscoelastic properties of the medium in comparison to the classical analysis of dynamic curves G’ and G” and shear creep compliance J(t). It allowed for a comprehensive description of a wide range of properties of kuzu starch pastes, depending on the conditions of pasting process. PMID:26599756

  9. Radiating black holes in Einstein-Maxwell-dilaton theory and cosmic censorship violation

    NASA Astrophysics Data System (ADS)

    Aniceto, Pedro; Pani, Paolo; Rocha, Jorge V.

    2016-05-01

    We construct exact, time-dependent, black hole solutions of Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling, a. For a = 1 this theory arises as the four-dimensional low-energy effective description of heterotic string theory. These solutions represent electrically charged, spherically symmetric black holes emitting or absorbing charged null fluids and generalize the Vaidya and Bonnor-Vaidya solutions of general relativity and of Einstein-Maxwell theory, respectively. The a = 1 case stands out as special, in the sense that it is the only choice of the coupling that allows for a time-dependent dilaton field in this class of solutions. As a by-product, when a = 1 we show that an electrically charged black hole in this theory can be overcharged by bombarding it with a stream of electrically charged null fluid, resulting in the formation of a naked singularity. This provides an example of cosmic censorship violation in an exact dynamical solution to low-energy effective string theory and in a case in which the total stress-energy tensor satisfies all energy conditions. When a ≠ 1, our solutions necessarily have a time-independent scalar field and consequently cannot be overcharged.

  10. Thermodynamics of phantom black holes in Einstein-Maxwell-dilaton theory

    NASA Astrophysics Data System (ADS)

    Rodrigues, Manuel E.; Oporto, Zui A. A.

    2012-05-01

    A thermodynamic analysis of the black hole solutions coming from the Einstein-Maxwell-dilaton theory in 4D is done. By considering the canonical and grand-canonical ensemble, we apply standard method as well as a recent method known as geometrothermodynamics. We are particularly interested in the characteristics of the so called phantom black hole solutions. We will analyze the thermodynamics of these solutions, the points of phase transition and their extremal limit. The thermodynamic stability is also analyzed. We obtain a mismatch between the results of the geometrothermodynamics method when compared with the ones obtained by the specific heat, revealing a weakness of the method, as well as possible limitations of its applicability to very pathological thermodynamic systems. We also found that normal and phantom solutions are locally and globally unstable, except for certain values of the coupled constant of the Einstein-Maxwell-dilaton action. We also show that the anti-Reissner-Nordstrom solution does not possess extremal limit nor phase transition points, contrary to the Reissner-Nordstrom case.

  11. String theory extensions of Einstein-Maxwell fields: The stationary case

    NASA Astrophysics Data System (ADS)

    Herrera-Aguilar, Alfredo; Kechkin, Oleg V.

    2004-01-01

    We present a new approach for generating solutions in heterotic string theory compactified down to three dimensions on a torus with d+n>2, where d and n stand for the number of compactified space-time dimensions and Abelian gauge fields, respectively. It is shown that in the case when d=2k+1, and n is arbitrary, one can apply a solution-generating procedure which consists of mapping seed solutions of the stationary Einstein theory with k Maxwell fields to the heterotic string realm by using pure field redefinitions. A novel feature of this method is that it is precisely the electromagnetic sector of the stationary electrovacuum that mainly gives rise to a nontrivial multidimensional metric. This approach leads to classes of solutions which are invariant with respect to the total group of three-dimensional charging symmetries of the heterotic string theory, i.e., to all finite transformations which generate charged solutions from neutral ones and preserve the asymptotics of the starting field configurations. As an application of the presented approach we generate a particular extension of the stationary Einstein-multi-Maxwell theory obtained on the basis of the Kerr-multi-Newman-NUT special class of solutions and establish the conditions under which the resulting multi-dimensional metric of the heterotic string theory is asymptotically flat.

  12. Electromagnetic and light scattering by nonspherical particles XV: Celebrating 150 years of Maxwell's electromagnetics

    NASA Astrophysics Data System (ADS)

    Macke, Andreas; Mishchenko, Michael I.

    2016-07-01

    The 15th Electromagnetic and Light Scattering Conference (ELS-XV) was held in Leipzig, Germany from 21 to 26 of June 2015 (Fig. 1). This conference built on the great success of the previous meetings held in Amsterdam (1995) [1], Helsinki (1997) [2], New York City (1998) [3], Vigo (1999), Halifax (2000) [4], Gainesville (2002) [5], Bremen (2003) [6], Salobreña (2005) [7], St. Petersburg (2006) [8], Bodrum (2007) [9], Hatfield (2008) [10], Helsinki (2010) [11], Taormina (2011) [12], and Lille [13] as well as the workshops held in Bremen (1996, 1998) and Moscow (1997). As usual, the main objective of this conference was to bring together scientists, engineers, and PhD students studying various aspects of electromagnetic scattering and to provide a relaxed atmosphere for in-depth discussion of theory, measurements, and applications. Furthermore, ELS-XV supported the United Nations "Year of Light" and celebrated the 150th anniversary of Maxwell's electromagnetics. Maxwell's paper on "A Dynamical Theory of the Electromagnetic Field" [14] was published in 1865 and has widely been acknowledged as one of the supreme achievements in the history of science.

  13. Customized finite difference Maxwell solver for elimination of numerical Cherenkov instability in EM-PIC code

    NASA Astrophysics Data System (ADS)

    Yu, Peicheng; Li, Fei; Dalichaouch, Thamine; Fiuza, Frederico; Decyk, Viktor; Davidson, Asher; Tableman, Adam; An, Weiming; Tsung, Frank; Fonseca, Ricardo; Lu, Wei; Vieira, Jorge; Silva, Luis; Mori, Warren

    2016-10-01

    we present a finite-difference-time-domain (FDTD) Maxwell solver for the particle-in-cell (PIC) algorithm, which is customized to effectively eliminate the numerical Cerenkov instability (NCI) which arises when a plasma (neutral or non-neutral) relativistically drifts on a grid when using the PIC algorithm. We control the EM dispersion curve in the direction of the plasma drift of a FDTD Maxwell solver by using a customized higher order finite difference operator for the spatial derivative along the direction of the drift (1& circ; direction). We show that this eliminates the main NCI modes with moderate | k1 | , while keeps additional main NCI modes well outside the range of physical interest with higher | k1 | . These main NCI modes can be easily filtered out along with first spatial aliasing NCI modes which are also at the edge of the fundamental Brillouin zone. The customized solver has the possible advantage of improved parallel scalability because it can be easily partitioned along 1& circ; which typically has many more cells than other directions for the problems of interest.

  14. Interaction of magnetic field in flow of Maxwell nanofluid with convective effect

    NASA Astrophysics Data System (ADS)

    Hayat, T.; Muhammad, Taseer; Shehzad, S. A.; Chen, G. Q.; Abbas, Ibrahim A.

    2015-09-01

    Magnetohydrodynamic (MHD) three-dimensional flow of Maxwell nanofluid subject to the convective boundary condition is investigated. The flow is generated by a bidirectional stretching surface. Thermophoresis and Brownian motion effects are present. Fluid is electrically conducted in the presence of a constant applied magnetic field. Unlike the previous cases even in the absence of nanoparticles, the correct formulation for the flow of Maxwell fluid in the presence of a magnetic field is established. Newly proposed boundary condition with the zero nanoparticles mass flux at the boundary is employed. The governing nonlinear boundary layer equations through appropriate transformations are reduced in the nonlinear ordinary differential system. The resulting nonlinear system has been solved for the velocities, temperature and nanoparticles concentration distributions. Convergence of the constructed solutions is verified. Effects of emerging parameters on the temperature and nanoparticles concentration are plotted and discussed. Numerical values of local Nusselt number are computed and analyzed. It is observed that the effects of magnetic parameter and the Biot number on the temperature and nanoparticles concentration are quite similar. Both the temperature and nanoparticles concentration are enhanced for the increasing value of magnetic parameter and Biot number.

  15. Entanglement entropy for a Maxwell field: Numerical calculation on a two-dimensional lattice

    NASA Astrophysics Data System (ADS)

    Casini, Horacio; Huerta, Marina

    2014-11-01

    We study entanglement entropy (EE) for a Maxwell field in (2 +1 ) dimensions. We do numerical calculations in two-dimensional lattices. This gives a concrete example of the general results of our recent work [1] on entropy for lattice gauge fields using an algebraic approach. To evaluate the entropies we extend the standard calculation methods for the entropy of Gaussian states in canonical commutation algebras to the more general case of algebras with center and arbitrary numerical commutators. We find that while the entropy depends on the details of the algebra choice, mutual information has a well defined continuum limit as predicted in [1]. We study several universal terms for the entropy of the Maxwell field and compare with the case of a massless scalar field. We find some interesting new phenomena: an "evanescent" logarithmically divergent term in the entropy with topological coefficient which does not have any correspondence with ultraviolet entanglement in the universal quantities, and a nonstandard way in which strong subadditivity is realized. Based on the results of our calculations we propose a generalization of strong subadditivity for the entropy on some algebras that are not in tensor product.

  16. Maxwell rheological model for lipid-shelled ultrasound microbubble contrast agents.

    PubMed

    Doinikov, Alexander A; Dayton, Paul A

    2007-06-01

    The present paper proposes a model that describes the encapsulation of microbubble contrast agents by the linear Maxwell constitutive equation. The model also incorporates the translational motion of contrast agent microbubbles and takes into account radiation losses due to the compressibility of the surrounding liquid. To establish physical features of the proposed model, comparative analysis is performed between this model and two existing models, one of which treats the encapsulation as a viscoelastic solid following the Kelvin-Voigt constitutive equation and the other assumes that the encapsulating layer behaves as a viscous Newtonian fluid. Resonance frequencies, damping coefficients, and scattering cross sections for the three shell models are compared in the regime of linear oscillation. Translational displacements predicted by the three shell models are examined by numerically calculating the general, nonlinearized equations of motion for weakly nonlinear excitation. Analogous results for free bubbles are also presented as a basis to which calculations made for encapsulated bubbles can be related. It is shown that the Maxwell shell model possesses specific physical features that are unavailable in the two other models.

  17. The Molecular Origin of Turbulence in a Flowing Gas According to James Clerk Maxwell

    NASA Astrophysics Data System (ADS)

    de Graffenried, Albert

    2007-11-01

    James Clerk Maxwell was an eminent physicist who operated out of the University of Edinburgh in the early 1800's. He is internationally famous for his derivation of the laws governing the propagation of electro-magnetic waves. He also derived an equation for the Viscosity of a gas (μ) in terms of its molecular parameters. This derivation established clearly and unequivocably that a real (viscous) flowing gas was a molecular fluid, that is, a flow of molecules which obeys the Kinetic Theory of Gases. Maxwell's derivation of the Viscosity of a gas takes place in a zone of a flowing gas which (1) is remote from any solid surface, and (2) is in a region having a linear velocity-gradient dvx/dy . The derivation which I will present today takes place in a zone of the flowing gas which is (1) immediately adjacent a solid surface, and (2) where the velocity gradient is unknown. My analytical approach, the parameters I use, and the theoretical concepts are all taken from Maxwell's derivation. I have simply re-arranged some of his equations in order to solve the 1-dimensional case of boundary-layer growth over an infinite flat plate, starting with a step-function of flow velocity, namely: vx(y,t) for the initial condition vx(y=0+,t=0+) = U0 ,viz: rectilinear flow as an initial condition. Using Maxwell's approach, we write the equation for Net Stream-Momentum Flux flowing through an element of area, day . This quantity is shown to be the difference between two Convolution integrals which Laplace transform readily into an equation in the s-plane which equation has the same form as a positive-feedback, single closed-loop amplifier gain equation, viz: Output = (input)x(transfer function). The solution in the Real plane shows vx(y,t) equal to the sum of two exponentials. The coefficients of the two exponents, r1 and r2 . are found by using the binomial equation which contains a square-root radical. If the argument under the radical (the radicand) is positive, the two roots are

  18. Preservation of physical properties of stochastic Maxwell equations with additive noise via stochastic multi-symplectic methods

    SciTech Connect

    Chen, Chuchu Hong, Jialin Zhang, Liying

    2016-02-01

    Stochastic Maxwell equations with additive noise are a system of stochastic Hamiltonian partial differential equations intrinsically, possessing the stochastic multi-symplectic conservation law. It is shown that the averaged energy increases linearly with respect to the evolution of time and the flow of stochastic Maxwell equations with additive noise preserves the divergence in the sense of expectation. Moreover, we propose three novel stochastic multi-symplectic methods to discretize stochastic Maxwell equations in order to investigate the preservation of these properties numerically. We make theoretical discussions and comparisons on all of the three methods to observe that all of them preserve the corresponding discrete version of the averaged divergence. Meanwhile, we obtain the corresponding dissipative property of the discrete averaged energy satisfied by each method. Especially, the evolution rates of the averaged energies for all of the three methods are derived which are in accordance with the continuous case. Numerical experiments are performed to verify our theoretical results.

  19. Models for low-energy Lorentz violation in the photon sector: Addendum to 'Consistency of isotropic modified Maxwell theory'

    NASA Astrophysics Data System (ADS)

    Klinkhamer, F. R.; Schreck, M.

    2012-03-01

    In a previous article, Klinkhamer and Schreck (2011) [1], we established the consistency of isotropic modified Maxwell theory for a finite range of the Lorentz-violating parameter κ, which includes both positive and negative values of κ. As an aside, we mentioned the existence of a physical model which, for low-energy photons, gives rise to isotropic modified Maxwell theory with a positive parameter κ (corresponding to a "slow" photon). Here, we present a related model which gives rise to isotropic modified Maxwell theory with a negative parameter κ (corresponding to a "fast" photon). Both models have an identical particle content, photon and Dirac particles, but differ in the type of spacetime manifold considered.

  20. Uniqueness theorem for black holes with Kaluza-Klein asymptotic in 5D Einstein-Maxwell gravity

    SciTech Connect

    Yazadjiev, Stoytcho

    2010-07-15

    In the present paper, we prove a uniqueness theorem for stationary multi-black hole configurations with Kaluza-Klein asymptotic in a certain sector of 5D Einstein-Maxwell gravity. As a part of the technical assumptions in the theorem, we assume that the Killing vector associated with the compact dimension is orthogonal to the other Killing vectors and that it is also hypersurface orthogonal. About the Maxwell field, we assume that it is invariant under the Killing symmetries and has a nonzero component only along the Killing vector associated with the compact dimension. We show that such multi-black hole configurations are uniquely specified by the interval structure, angular momenta of the horizons, magnetic charges, and the magnetic flux. A straightforward generalization of the uniqueness theorem for 5D Einstein-Maxwell-dilaton gravity is also given.

  1. Detailed analysis of the effects of stencil spatial variations with arbitrary high-order finite-difference Maxwell solver

    NASA Astrophysics Data System (ADS)

    Vincenti, H.; Vay, J.-L.

    2016-03-01

    Very high order or pseudo-spectral Maxwell solvers are the method of choice to reduce discretization effects (e.g. numerical dispersion) that are inherent to low order Finite-Difference Time-Domain (FDTD) schemes. However, due to their large stencils, these solvers are often subject to truncation errors in many electromagnetic simulations. These truncation errors come from non-physical modifications of Maxwell's equations in space that may generate spurious signals affecting the overall accuracy of the simulation results. Such modifications for instance occur when Perfectly Matched Layers (PMLs) are used at simulation domain boundaries to simulate open media. Another example is the use of arbitrary order Maxwell solver with domain decomposition technique that may under some condition involve stencil truncations at subdomain boundaries, resulting in small spurious errors that do eventually build up. In each case, a careful evaluation of the characteristics and magnitude of the errors resulting from these approximations, and their impact at any frequency and angle, requires detailed analytical and numerical studies. To this end, we present a general analytical approach that enables the evaluation of numerical errors of fully three-dimensional arbitrary order finite-difference Maxwell solver, with arbitrary modification of the local stencil in the simulation domain. The analytical model is validated against simulations of domain decomposition technique and PMLs, when these are used with very high-order Maxwell solver, as well as in the infinite order limit of pseudo-spectral solvers. Results confirm that the new analytical approach enables exact predictions in each case. It also confirms that the domain decomposition technique can be used with very high-order Maxwell solvers and a reasonably low number of guard cells with negligible effects on the whole accuracy of the simulation.

  2. Derivation of the scalar radiative transfer equation from energy conservation of Maxwell's equations in the far field.

    PubMed

    Ripoll, Jorge

    2011-08-01

    In this paper the expression for the radiative transfer equation (RTE) commonly used when describing light propagation in biological tissues is derived directly from the equation of energy conservation of Maxwell's equations (Poynting's theorem) by making use of a volume-averaged expression for the time-averaged flow of energy. The derivation is presented step by step with Maxwell's equations as the starting point, analyzing all approximations taken in order to arrive at the expression of the scalar RTE employed in biomedical applications, which neglects particle nonsphericity and orientation, depolarization, and coherence effects.

  3. Direct time integration of Maxwell's equations in linear dispersive media with absorption for scattering and propagation of femtosecond electromagnetic pulses

    NASA Technical Reports Server (NTRS)

    Joseph, Rose M.; Hagness, Susan C.; Taflove, Allen

    1991-01-01

    The initial results for femtosecond pulse propagation and scattering interactions for a Lorentz medium obtained by a direct time integration of Maxwell's equations are reported. The computational approach provides reflection coefficients accurate to better than 6 parts in 10,000 over the frequency range of dc to 3 x 10 to the 16th Hz for a single 0.2-fs Gaussian pulse incident upon a Lorentz-medium half-space. New results for Sommerfeld and Brillouin precursors are shown and compared with previous analyses. The present approach is robust and permits 2D and 3D electromagnetic pulse propagation directly from the full-vector Maxwell's equations.

  4. Hawking Radiation and Entropy of a Dynamic Dilaton-Maxwell Black Hole with a New Tortoise Coordinate Transformation

    NASA Astrophysics Data System (ADS)

    Lan, Xiao-Gang

    2013-05-01

    By introducing a new tortoise coordinate transformation, we apply Damour-Ruffini-Sannan method to study the Hawking radiation of massive scalar particles in a dynamic Dilaton-Maxwell black hole. We find that Hawking radiation spectrum shows still the blackbody one, while the Hawking temperature is significantly changed. Additionally, by adopting the thin film method, we calculate the entropy of a dynamic Dilaton-Maxwell black hole. The result indicates that the entropy for such a black hole is still in proportional to the area of its event horizon.

  5. Gaussian statistics for palaeomagnetic vectors

    USGS Publications Warehouse

    Love, J.J.; Constable, C.G.

    2003-01-01

    With the aim of treating the statistics of palaeomagnetic directions and intensities jointly and consistently, we represent the mean and the variance of palaeomagnetic vectors, at a particular site and of a particular polarity, by a probability density function in a Cartesian three-space of orthogonal magnetic-field components consisting of a single (unimoda) non-zero mean, spherically-symmetrical (isotropic) Gaussian function. For palaeomagnetic data of mixed polarities, we consider a bimodal distribution consisting of a pair of such symmetrical Gaussian functions, with equal, but opposite, means and equal variances. For both the Gaussian and bi-Gaussian distributions, and in the spherical three-space of intensity, inclination, and declination, we obtain analytical expressions for the marginal density functions, the cumulative distributions, and the expected values and variances for each spherical coordinate (including the angle with respect to the axis of symmetry of the distributions). The mathematical expressions for the intensity and off-axis angle are closed-form and especially manageable, with the intensity distribution being Rayleigh-Rician. In the limit of small relative vectorial dispersion, the Gaussian (bi-Gaussian) directional distribution approaches a Fisher (Bingham) distribution and the intensity distribution approaches a normal distribution. In the opposite limit of large relative vectorial dispersion, the directional distributions approach a spherically-uniform distribution and the intensity distribution approaches a Maxwell distribution. We quantify biases in estimating the properties of the vector field resulting from the use of simple arithmetic averages, such as estimates of the intensity or the inclination of the mean vector, or the variances of these quantities. With the statistical framework developed here and using the maximum-likelihood method, which gives unbiased estimates in the limit of large data numbers, we demonstrate how to

  6. MQSA National Statistics

    MedlinePlus

    ... Standards Act and Program MQSA Insights MQSA National Statistics Share Tweet Linkedin Pin it More sharing options ... but should level off with time. Archived Scorecard Statistics 2017 Scorecard Statistics 2016 Scorecard Statistics (Archived) 2015 ...

  7. Recent Developments on the Numerical Upscaling and Homogenization of the Quasi-Static Maxwell's Equations

    NASA Astrophysics Data System (ADS)

    Caudillo Mata, L.; Haber, E.

    2013-12-01

    Luz Angelica Caudillo-Mata, Eldad Haber Geophysics Department, The University of British Columbia. 4013-2207 Main Mall, Vancouver, B.C., Canada. Z. C. V6R 1Z4 Key words: Finite Volume, Quasi-static Maxwell's Equations, Optimization, Upscaling, Homogenization, Exploration Geophysics. Abstract: Mineral exploration has exploited the application of mathematical modelling and inversion methods to electromagnetic data by creating a thoughtful workflow that assists in the identification of potential geological targets, the understanding of the larger scale stratigraphy and structure in which a deposit might be located, or delineating finer scale detail in an existing deposit. [1] In recent years, electromagnetic modelling and inversion techniques based on finite volume and finite elements have been studied extensively due to their usefulness in theory as well as in practice [2]. Although the theoretical foundation for these methods is straight-forward, it can face major difficulties when used to simulate realistic situations. One of the fundamental issues is modelling the vast heterogeneity of geological targets in terms of scale, magnitude and anisotropy. Robust and accurate simulations require very fine meshes, especially when the earth is highly heterogeneous. Such meshes are difficult-to-work-with and may lead to very expensive-to-compute simulations when considering large earth-multiscale scenarios. For instance, geological characterizations typically contain on the order of 1e7 to 1e8 cells. These models, which are referred as fine models, represent geological variations on very fine scales vertically, though their areal resolution is still relatively coarse [3]. Numerical upscaling is a mathematical procedure that strive to develop coarse scale models to accurately approximate fine scale ones. Therefore, it is a useful resource to alleviate the computational cost. Upscaling of Maxwell's equations presents big challenges such as choosing the appropriate upscaling

  8. Pulsed plane wave analytic solutions for generic shapes and the validation of Maxwell's equations solvers

    NASA Technical Reports Server (NTRS)

    Yarrow, Maurice; Vastano, John A.; Lomax, Harvard

    1992-01-01

    Generic shapes are subjected to pulsed plane waves of arbitrary shape. The resulting scattered electromagnetic fields are determined analytically. These fields are then computed efficiently at field locations for which numerically determined EM fields are required. Of particular interest are the pulsed waveform shapes typically utilized by radar systems. The results can be used to validate the accuracy of finite difference time domain Maxwell's equations solvers. A two-dimensional solver which is second- and fourth-order accurate in space and fourth-order accurate in time is examined. Dielectric media properties are modeled by a ramping technique which simplifies the associated gridding of body shapes. The attributes of the ramping technique are evaluated by comparison with the analytic solutions.

  9. Light-opals interaction modeling by direct numerical solution of Maxwell's equations.

    PubMed

    Vaccari, Alessandro; Lesina, Antonino Calà; Cristoforetti, Luca; Chiappini, Andrea; Crema, Luigi; Calliari, Lucia; Ramunno, Lora; Berini, Pierre; Ferrari, Maurizio

    2014-11-03

    This work describes a 3-D Finite-Difference Time-Domain (FDTD) computational approach for the optical characterization of an opal photonic crystal. To fully validate the approach we compare the computed transmittance of a crystal model with the transmittance of an actual crystal sample, as measured over the 400 ÷ 750 nm wavelength range. The opal photonic crystal considered has a face-centered cubic (FCC) lattice structure of spherical particles made of polystyrene (a non-absorptive material with constant relative dielectric permittivity). Light-matter interaction is described by numerically solving Maxwell's equations via a parallelized FDTD code. Periodic boundary conditions (PBCs) at the outer edges of the crystal are used to effectively enforce an infinite lateral extension of the sample. A method to study the propagating Bloch modes inside the crystal bulk is also proposed, which allows the reconstruction of the ω-k dispersion curve for k sweeping discretely the Brillouin zone of the crystal.

  10. Power law of shear viscosity in Einstein-Maxwell-Dilaton-Axion model

    NASA Astrophysics Data System (ADS)

    Ling, Yi; Xian, Zhuoyu; Zhou, Zhenhua

    2017-02-01

    We construct charged black hole solutions with hyperscaling violation in the infrared (IR) region in Einstein-Maxwell-Dilaton-Axion theory and investigate the temperature behavior of the ratio of holographic shear viscosity to the entropy density. When translational symmetry breaking is relevant in the IR, the power law of the ratio is verified numerically at low temperature T, namely, η/s ∼ T κ , where the values of exponent κ coincide with the analytical results. We also find that the exponent κ is not affected by irrelevant current, but is reduced by the relevant current. Supported by National Natural Science Foundation of China (11275208, 11575195), Opening Project of Shanghai Key Laboratory of High Temperature Superconductors (14DZ2260700) and Jiangxi Young Scientists (JingGang Star) Program and 555 Talent Project of Jiangxi Province

  11. Boundary conditions for Maxwell fields in Kerr-AdS spacetimes

    NASA Astrophysics Data System (ADS)

    Wang, Mengjie

    2016-05-01

    Perturbative methods are useful to study the interaction between black holes and test fields. The equation for a perturbation itself, however, is not complete to study such a composed system if we do not assign physically relevant boundary conditions. Recently we have proposed a new type of boundary conditions for Maxwell fields in Kerr-anti-de Sitter (Kerr-AdS) spacetimes, from the viewpoint that the AdS boundary may be regarded as a perfectly reflecting mirror, in the sense that energy flux vanishes asymptotically. In this paper, we prove explicitly that a vanishing energy flux leads to a vanishing angular momentum flux. Thus, these boundary conditions may be dubbed as vanishing flux boundary conditions.

  12. Exact axisymmetric solutions of the Maxwell equations in a nonlinear nondispersive medium.

    PubMed

    Petrov, E Yu; Kudrin, A V

    2010-05-14

    The features of propagation of intense waves are of great interest for theory and experiment in electrodynamics and acoustics. The behavior of nonlinear waves in a bounded volume is of special importance and, at the same time, is an extremely complicated problem. It seems almost impossible to find a rigorous solution to such a problem even for any model of nonlinearity. We obtain the first exact solution of this type. We present a new method for deriving exact solutions of the Maxwell equations in a nonlinear medium without dispersion and give examples of the obtained solutions that describe propagation of cylindrical electromagnetic waves in a nonlinear nondispersive medium and free electromagnetic oscillations in a cylindrical cavity resonator filled with such a medium.

  13. Field Dynamics of Coherent Synchrotron Radiation Using a Direct Numerical Solution of Maxwell's Equations

    SciTech Connect

    Novokhatski, A.; /SLAC

    2011-08-17

    We present and discuss the properties of the coherent electromagnetic fields of a very short, ultrarelativistic bunch in a rectangular vacuum chamber inside a bending magnet. The analysis is based on the results of a direct numerical solution of Maxwell's equations together with Newton's equations. We use a new dispersion-free time-domain algorithm which employs a more efficient use of finite element mesh techniques and, hence, produces self-consistent and stable solutions for very short bunches. We investigate the fine structure of the coherent synchrotron radiation fields. We also discuss coherent edge radiation. We present a clear picture of the field using the electric field lines constructed from the numerical solutions. This method should be useful in the study of existing and future concepts of particle accelerators and ultrafast coherent light sources, where high peak currents and very short bunches are envisioned.

  14. Localizing gravity on Maxwell gauged CP{sup 1} model in six dimensions

    SciTech Connect

    Kodama, Yuta; Kokubu, Kento; Sawado, Nobuyuki

    2008-08-15

    We shall consider a 3-brane embedded in six-dimensional space-time with a negative bulk cosmological constant. The 3-brane is constructed by a topological soliton solution living in two-dimensional axially symmetric transverse subspace. Similar to most previous works of six-dimensional soliton models, our Maxwell gauged CP{sup 1} brane model can also achieve localizing gravity around the 3-brane. The CP{sup 1} field is described by a scalar doublet and derived from the O(3) sigma model by projecting it onto two-dimensional complex space. In that sense, our framework is more effective than other solitonic brane models concerning gauge theory. We shall also discuss the linear stability analysis for our new model by fluctuating all fields.

  15. Comparisons of the Maxwell and CLL Gas/Surface Interaction Models Using DSMC

    NASA Technical Reports Server (NTRS)

    Hedahl, Marc O.

    1995-01-01

    Two contrasting models of gas-surface interactions are studied using the Direct Simulation Monte Carlo (DSMC) method. The DSMC calculations examine differences in predictions of aerodynamic forces and heat transfer between the Maxwell and Cercignani-Lampis-Lord (CLL) models for flat plate configurations at freestream conditions corresponding to a 140 km orbit around Venus. The size of the flat plate is that of one of the solar panels on the Magellan spacecraft, and the freestream conditions are one of those experienced during aerobraking maneuvers. Results are presented for both a single flat plate and a two-plate configuration as a function of angle of attack and gas-surface accommodation coefficients. The two plate system is not representative of the Magellan geometry, but is studied to explore possible experiments that might be used to differentiate between the two gas surface interaction models.

  16. A CYLINDRICALLY SYMMETRIC UNIAXIAL PML MAXWELL SOLVER FOR TRANSIENT ATMOSPHERIC ELECTRICITY SIMULATIONS

    SciTech Connect

    E. M. SYMBALISTY

    2001-07-01

    The recent interest in high altitude discharges known as red sprites, blue jets, and elves has stimulated the modeling of transient atmospheric electricity. The modeling of these high altitude discharges require an initiating cloud-to-ground or intracloud lightning event in order to pre-condition the electric field between the cloud tops and the ionosphere. In this short paper we describe a finite difference time domain (FDTD) numerical solution of Maxwell's equations based on the Yee (Yee 1966) algorithm coupled with a uniaxial perfectly matched layer (PML, Berenger 1994) boundary treatment. The PML theory has advanced considerably since its original formulation in cartesian coordinates for lossless media, and is computationally efficient to implement. Another boundary treatment possibility for our sources that produce radiative and electrostatic fields, which we do not consider here, is a multipole expansion in the time domain for the electromagnetic fields.

  17. A New Comment on Dyson's Exposition of Feynman's Proof of Maxwell Equations

    SciTech Connect

    Pombo, Claudia

    2009-03-10

    A paper by Dyson, published nearly two decades ago, describing Feynman's proof of Maxwell equations, has generated many comments, analysis, discussions and generalizations of the proof. Feynman's derivation is assumed to be based on two main sets of equations. One is supposed to be the second law of Newton and the other a set of basic commutation relations from quantum physics.Here we present a new comment on this paper, focusing mainly on the initial arguments and applying a new method of analysis and interpretation of physics, named observational realism. The present discussion does not alter the technical steps of Feynman, but do clarify their basis. We show that Newton's physics is not a starting point in Feynman's derivation, neither is quantum physics involved in it, but the foundations of relativity only.

  18. Canonicalizable gyrocenter and structure-preserving geometric algorithms for the Vlasov-Maxwell system

    NASA Astrophysics Data System (ADS)

    Qin, Hong

    2016-10-01

    Littlejohn's introduction of the non-canonical symplectic structure for the gyrocenter dynamics revolutionized plasma kinetic theory. The discovery of the non-canonical symplectic algorithm for gyrocenters initiated the search for symplectic algorithms for the gyrokinetic system. This effort is enforced by the recent discovery of canonical and non-canonical symplectic algorithms for the Vlasov-Maxwell (VM) system. However, symplectic algorithms for the gyrokinetic system remain elusive despite intense effort. In retrospect, the success of the symplectic algorithms for the VM system can be attributed to its global canonicalizability. Darboux's theorem ensures that any symplectic structure is locally canonicalizable, but not necessarily globally. Indeed, Littlejohn's gyrocenter is not globally canonicalizable. In this talk, I will show to construct a different gyrocenter that is globally canonicalizable. It should be a good starting point for developing symplectic algorithms for the gyrokinetic system. Research supported by the U.S. Department of Energy (DE-AC02-09CH11466).

  19. Berry phase and anomalous velocity of Weyl fermions and Maxwell photons

    NASA Astrophysics Data System (ADS)

    Stone, Michael

    2016-12-01

    We consider two systems of wave equations whose wave packet solutions have trajectories that are altered by the “anomalous velocity” effect of a Berry curvature. The first is the matrix Weyl equation describing cyclotron motion of a charged massless fermion. The second is Maxwell equations for the whispering-gallery modes of light in a cylindrical waveguide. In the case of the massless fermion, the anomalous velocity is obscured by the contribution from the magnetic moment. In the whispering-gallery modes, the anomalous velocity causes the circumferential light ray to creep up the cylinder at the rate of one wavelength per orbit, and can be identified as a continuous version of the Imbert-Federov effect.

  20. POL-2: a polarimeter for the James-Clerk-Maxwell telescope

    NASA Astrophysics Data System (ADS)

    Friberg, Per; Bastien, Pierre; Berry, David; Savini, Giorgio; Graves, Sarah F.; Pattle, Kate

    2016-07-01

    The POL-2 polarimeter for the SCUBA-2 10 000 pixel Terahertz camera on the James Clerk Maxwell Telescope (JCMT) in it's late state of commissioning. Proposals have been accepted for POL-2 and general observing will start in August 2016. SCUBA-2 has a field of view of 43 arcmin at both of the 850 and 450 μm focal planes. POL-2 will map the sky in the the 850 μm band. The POL-2 polarimeter utilizes three optical components: a half wave plate and two wire-grid polarizers used as calibrator and analyzer covering the full field of SCUBA-2. We describe the instrument, data acquisition and features/artifacts that have been encountered during the commissioning.

  1. Hall effects on peristaltic flow of a Maxwell fluid in a porous medium

    NASA Astrophysics Data System (ADS)

    Hayat, T.; Ali, N.; Asghar, S.

    2007-04-01

    This work is concerned with the peristaltic transport of an incompressible, electrically conducting Maxwell fluid in a planar channel. The flow in the porous space is due to a sinusoidal wave traveling on the channel walls. The Hall effect is taken into account and permeability of porous medium is considered uniform. Modified Darcy's law has been used to model the governing equation. An analytical solution is obtained, which satisfies the momentum equation for the case in which the amplitude ratio is small. The present theoretical model may be considered as mathematical representation to the case of gall bladder and bile duct with stones and dynamics of blood flow in living creatures. Finally, the graphical results are reported and discussed for various values of the physical parameters of interest.

  2. Evaluating lightning hazards to building environments using explicit numerical solutions of Maxwell's equations

    NASA Technical Reports Server (NTRS)

    Collier, Richard S.; Mckenna, Paul M.; Perala, Rodney A.

    1991-01-01

    The objective here is to describe the lightning hazards to buildings and their internal environments using advanced formulations of Maxwell's Equations. The method described is the Three Dimensional Finite Difference Time Domain Solution. It can be used to solve for the lightning interaction with such structures in three dimensions with the inclusion of a considerable amount of detail. Special techniques were developed for including wire, plumbing, and rebar into the model. Some buildings have provisions for lightning protection in the form of air terminals connected to a ground counterpoise system. It is shown that fields and currents within these structures can be significantly high during a lightning strike. Time lapse video presentations were made showing the electric and magnetic field distributions on selected cross sections of the buildings during a simulated lightning strike.

  3. The general Lie group and similarity solutions for the one-dimensional Vlasov-Maxwell equations

    NASA Technical Reports Server (NTRS)

    Roberts, D.

    1985-01-01

    The general Lie point transformation group and the associated reduced differential equations and similarity forms for the solutions are derived here for the coupled (nonlinear) Vlasov-Maxwell equations in one spatial dimension. The case of one species in a background is shown to admit a larger group than the multispecies case. Previous exact solutions are shown to be special cases of the above solutions, and many of the new solutions are found to constrain the form of the distribution function much more than, for example, the BGK solutions do. The individual generators of the Lie group are used to find the possible subgroups. Finally, a simple physical argument is given to show that the asymptotic solution for a one-species, one-dimensional plasma is one of the general similarity solutions.

  4. Motion-induced radiation from electrons moving in Maxwell's fish-eye

    PubMed Central

    Liu, Yangjie; Ang, L. K.

    2013-01-01

    In Čerenkov radiation and transition radiation, evanescent wave from motion of charged particles transfers into radiation coherently. However, such dissipative motion-induced radiations require particles to move faster than light in medium or to encounter velocity transition to pump energy. Inspired by a method to detect cloak by observing radiation of a fast-moving electron bunch going through it by Zhang et al., we study the generation of electron-induced radiation from electrons' interaction with Maxwell's fish-eye sphere. Our calculation shows that the radiation is due to a combination of Čerenkov radiation and transition radiation, which may pave the way to investigate new schemes of transferring evanescent wave to radiation. PMID:24166002

  5. The Hamiltonian structure and Euler-Poincare formulation of the Vlasov-Maxwell and gyrokinetic systems

    SciTech Connect

    Squire, J.; Tang, W. M.; Qin, H.; Chandre, C.

    2013-02-15

    We present a new variational principle for the gyrokinetic system, similar to the Maxwell-Vlasov action presented in H. Cendra et al., [J. Math. Phys. 39, 3138 (1998)]. The variational principle is in the Eulerian frame and based on constrained variations of the phase space fluid velocity and particle distribution function. Using a Legendre transform, we explicitly derive the field theoretic Hamiltonian structure of the system. This is carried out with a modified Dirac theory of constraints, which is used to construct meaningful brackets from those obtained directly from Euler-Poincare theory. Possible applications of these formulations include continuum geometric integration techniques, large-eddy simulation models, and Casimir type stability methods.

  6. Dynamic simulation of electromechanical systems: from Maxwell's theory to common-rail diesel injection.

    PubMed

    Kurz, S; Becker, U; Maisch, H

    2001-05-01

    This paper describes the state-of-the-art of dynamic simulation of electromechanical systems. Electromechanical systems can be split into electromagnetic and mechanical subsystems, which are described by Maxwell's equations and by Newton's law, respectively. Since such systems contain moving parts, the concepts of Lorentz and Galilean relativity are briefly addressed. The laws of physics are formulated in terms of (partial) differential equations. Numerical methods ultimately aim at linear systems of equations, which can be solved efficiently on digital computers. The various discretization methods for performing this task are discussed. Special emphasis is placed on domain decomposition as a framework for the coupling of different numerical methods such as the finite element method and the boundary element method. The paper concludes with descriptions of some applications of industrial relevance: a high performance injection valve and an electromechanical relay.

  7. A theoretical derivation of the dilatancy equation for brittle rocks based on Maxwell model

    NASA Astrophysics Data System (ADS)

    Li, Jie; Huang, Houxu; Wang, Mingyang

    2017-01-01

    In this paper, the micro-cracks in the brittle rocks are assumed to be penny shaped and evenly distributed; the damage and dilatancy of the brittle rocks is attributed to the growth and expansion of numerous micro-cracks under the local tensile stress. A single crack's behaviour under the local tensile stress is generalized to all cracks based on the distributed damage mechanics. The relationship between the local tensile stress and the external loading is derived based on the Maxwell model. The damage factor corresponding to the external loading is represented using the p-alpha (p-α) model. A dilatancy equation that can build up a link between the external loading and the rock dilatancy is established. A test of dilatancy of a brittle rock under triaxial compression is conducted; the comparison between experimental results and our theoretical results shows good consistency.

  8. Superconvergence of mixed finite element approximations to 3-D Maxwell's equations in metamaterials

    NASA Astrophysics Data System (ADS)

    Huang, Yunqing; Li, Jichun; Yang, Wei; Sun, Shuyu

    2011-09-01

    Numerical simulation of metamaterials has attracted more and more attention since 2000, after the first metamaterial with negative refraction index was successfully constructed. In this paper we construct a fully-discrete leap-frog type finite element scheme to solve the three-dimensional time-dependent Maxwell's equations when metamaterials are involved. First, we obtain some superclose results between the interpolations of the analytical solutions and finite element solutions obtained using arbitrary orders of Raviart-Thomas-Nédélec mixed spaces on regular cubic meshes. Then we prove the superconvergence result in the discrete l2 norm achieved for the lowest-order Raviart-Thomas-Nédélec space. To our best knowledge, such superconvergence results have never been obtained elsewhere. Finally, we implement the leap-frog scheme and present numerical results justifying our theoretical analysis.

  9. Information flow and optimal protocol for a Maxwell-demon single-electron pump

    NASA Astrophysics Data System (ADS)

    Bergli, J.; Galperin, Y. M.; Kopnin, N. B.

    2013-12-01

    We study the entropy and information flow in a Maxwell-demon device based on a single-electron transistor with controlled gate potentials. We construct the protocols for measuring the charge states and manipulating the gate voltages, which minimizes irreversibility for (i) constant input power from the environment or (ii) given energy gain. Charge measurement is modeled by a series of detector readouts for time-dependent gate potentials, and the amount of information obtained is determined. The protocols optimize irreversibility that arises due to (i) enlargement of the configuration space on opening the barriers, and (ii) finite rate of operation. These optimal protocols are general and apply to all systems in which barriers between different regions can be manipulated.

  10. Hamiltonian particle-in-cell methods for Vlasov-Maxwell equations

    NASA Astrophysics Data System (ADS)

    He, Yang; Sun, Yajuan; Qin, Hong; Liu, Jian

    2016-09-01

    In this paper, we study the Vlasov-Maxwell equations based on the Morrison-Marsden-Weinstein bracket. We develop Hamiltonian particle-in-cell methods for this system by employing finite element methods in space and splitting methods in time. In order to derive the semi-discrete system that possesses a discrete non-canonical Poisson structure, we present a criterion for choosing the appropriate finite element spaces. It is confirmed that some conforming elements, e.g., Nédélec's mixed elements, satisfy this requirement. When the Hamiltonian splitting method is used to discretize this semi-discrete system in time, the resulting algorithm is explicit and preserves the discrete Poisson structure. The structure-preserving nature of the algorithm ensures accuracy and fidelity of the numerical simulations over long time.

  11. Maxwell, Yang-Mills, Weyl and eikonal fields defined by any null shear-free congruence

    NASA Astrophysics Data System (ADS)

    Kassandrov, Vladimir V.; Rizcallah, Joseph A.

    We show that (specifically scaled) equations of shear-free null geodesic congruences on the Minkowski space-time possess intrinsic self-dual, restricted gauge and algebraic structures. The complex eikonal, Weyl 2-spinor, SL(2, ℂ) Yang-Mills and complex Maxwell fields, the latter produced by integer-valued electric charges (“elementary” for the Kerr-like congruences), can all be explicitly associated with any shear-free null geodesic congruence. Using twistor variables, we derive the general solution of the equations of the shear-free null geodesic congruence (as a modification of the Kerr theorem) and analyze the corresponding “particle-like” field distributions, with bounded singularities of the associated physical fields. These can be obtained in a straightforward algebraic way and exhibit nontrivial collective dynamics simulating physical interactions.

  12. Exact Stationary and Non-stationary Solutions to Inelastic Maxwell Model with Infinite Energy

    NASA Astrophysics Data System (ADS)

    Ilyin, Oleg

    2016-11-01

    The one-dimensional inelastic Boltzmann equation with a constant collision rate (the Maxwell model) is considered. It is shown that for special values of restitution parameter there exists a stationary solution with the characteristic function in the form e^{-P(log (z))z}, where P is a periodic function. The corresponding distribution function belongs to a one special class of stochastic processes termed as a generalized stable in the probability theory. The Fourier transform of the non-stationary equation has the solution bigl (1+P(log (z))zbigr )e^{-Q(log (z))z}. It is proved that this solution is a characteristic function if periodic functions P, Q satisfy some not very restrictive conditions. The stationary and non-stationary solutions correspond to a gas with infinite temperature.

  13. Absorption coefficient modeling of microcrystalline silicon thin film using Maxwell-Garnett effective medium theory.

    PubMed

    Chen, Sheng-Hui; Wang, Hsuan-Wen; Chang, Ting-Wei

    2012-03-12

    Considering the Mott-Davis density of state model and Rayleigh scattering effect, we present an approach to model the absorption profile of microcrystalline silicon thin films in this paper. Maxwell-Garnett effective medium theory was applied to analyze the absorption curves. To validate the model, several experimental profiles have been established and compared with those results from the model. With the assistance of the genetic algorithm, our results show that the absorption curves from the model are in good agreement with the experiments. Our findings also indicate that, as the crystal volume fraction increases, not only do the defects in amorphous silicon reduce, but the bulk scattering effect is gradually enhanced as well.

  14. A new identification method of viscoelastic behavior: Application to the generalized Maxwell model

    NASA Astrophysics Data System (ADS)

    Renaud, Franck; Dion, Jean-Luc; Chevallier, Gaël; Tawfiq, Imad; Lemaire, Rémi

    2011-04-01

    This paper focuses on the generalized Maxwell model (GMM) identification. The formulation of the transfer function of the GMM is defined, as well as its asymptotes. To compare identification methods of the parameters of the GMM, a test transfer function and two quality indicators are defined. Then, three graphical methods are described, the enclosing curve method, the CRONE method and an original one. But the results of graphical methods are not good enough. Thus, two optimization recursive processes are described to improve the results of graphical methods. The first one is based on an unconstrained non-linear optimization algorithm and the second one is original and allows constraining identified parameters. This new process uses the asymptotes of the modulus and the phase of the transfer function of the GMM. The result of the graphical method optimized with the new process is very accurate and fast.

  15. Quantum power source: putting in order of a Brownian motion without Maxwell's demon

    NASA Astrophysics Data System (ADS)

    Aristov, Vitaly V.; Nikulov, A. V.

    2003-07-01

    The problem of possible violation of the second law of thermodynamics is discussed. It is noted that the task of the well known challenge to the second law called Maxwell's demon is put in order a chaotic perpetual motion and if any ordered Brownian motion exists then the second law can be broken without this hypothetical intelligent entity. The postulate of absolute randomness of any Brownian motion saved the second law in the beginning of the 20th century when it was realized as perpetual motion. This postulate can be proven in the limits of classical mechanics but is not correct according to quantum mechanics. Moreover some enough known quantum phenomena, such as the persistent current at non-zero resistance, are an experimental evidence of the non-chaotic Brownian motion with non-zero average velocity. An experimental observation of a dc quantum power soruce is interperted as evidence of violation of the second law.

  16. Implicit scheme for Maxwell equations solution in case of flat 3D domains

    NASA Astrophysics Data System (ADS)

    Boronina, Marina; Vshivkov, Vitaly

    2016-02-01

    We present a new finite-difference scheme for Maxwell's equations solution for three-dimensional domains with different scales in different directions. The stability condition of the standard leap-frog scheme requires decreasing of the time-step with decreasing of the minimal spatial step, which depends on the minimal domain size. We overcome the conditional stability by modifying the standard scheme adding implicitness in the direction of the smallest size. The new scheme satisfies the Gauss law for the electric and magnetic fields in the final- differences. The approximation order, the maintenance of the wave amplitude and propagation speed, the invariance of the wave propagation on angle with the coordinate axes are analyzed.

  17. Evaluation of scanning Maxwell-stress microscopy for SPM-based nanoelectronics

    NASA Astrophysics Data System (ADS)

    Dagata, J. A.

    1997-09-01

    A preliminary evaluation of the compatibility, spatial resolution, and sensitivity of scanning Maxwell-stress microscopy (SMM) as an in situ diagnostic technique for SPM oxidation of silicon is presented. These results indicate that SMM will provide us with a more detailed understanding of the reaction mechanism which occurs at the tip - sample junction during SPM oxidation. SMM also appears to be a promising technique for simultaneously investigating dimensional and electrical properties of molecular distributions within highly complex micro-environments such as phase-separated polymer systems. This effort to integrate SPM-based fabrication and diagnostics is discussed in terms of the development of predictive physical models for the optimization of the fabrication process and possible choices of future SPM-based nanodevices.

  18. Cylindrical and spherical space equivalents to the plane wave expansion technique of Maxwell's wave equations

    NASA Astrophysics Data System (ADS)

    Gauthier, Robert C.; Alzahrani, Mohammed A.; Jafari, Seyed Hamed

    2015-02-01

    The plane wave expansion (PWM) technique applied to Maxwell's wave equations provides researchers with a supply of information regarding the optical properties of dielectric structures. The technique is well suited for structures that display a linear periodicity. When the focus is directed towards optical resonators and structures that lack linear periodicity the eigen-process can easily exceed computational resources and time constraints. In the case of dielectric structures which display cylindrical or spherical symmetry, a coordinate system specific set of basis functions have been employed to cast Maxwell's wave equations into an eigen-matrix formulation from which the resonator states associated with the dielectric profile can be obtained. As for PWM, the inverse of the dielectric and field components are expanded in the basis functions (Fourier-Fourier-Bessel, FFB, in cylindrical and Fourier- Bessel-Legendre, BLF, in spherical) and orthogonality is employed to form the matrix expressions. The theoretical development details will be presented indicating how certain mathematical complications in the process have been overcome and how the eigen-matrix can be tuned to a specific mode type. The similarities and differences in PWM, FFB and BLF are presented. In the case of structures possessing axial cylindrical symmetry, the inclusion of the z axis component of propagation constant makes the technique applicable to photonic crystal fibers and other waveguide structures. Computational results will be presented for a number of different dielectric geometries including Bragg ring resonators, cylindrical space slot channel waveguides and bottle resonators. Steps to further enhance the computation process will be reported.

  19. Electromagnetic and Light Scattering by Nonspherical Particles XV: Celebrating 150 Years of Maxwell's Electromagnetics

    NASA Technical Reports Server (NTRS)

    Macke, Andreas; Mishchenko, Michael I.

    2015-01-01

    The 15th Electromagnetic and Light Scattering Conference (ELS-XV) was held in Leipzig, Germany from 21 to 26 of June 2015. This conference built on the great success of the previous meetings held in Amsterdam (1995), Helsinki(1997) [2], New York City(1998) [3], Vigo (1999),Halifax (2000), Gainesville (2002), Bremen (2003), Salobreña (2005), St. Petersburg (2006), Bodrum (2007), Hatfield (2008), Helsinki (2010), Taormina (2011), and Lille as well as the workshops held in Bremen (1996,1998) and Moscow (1997). As usual, the main objective of this conference was to bring together scientists, engineers, and PhD students studying various aspects of electromagnetic scattering and to provide a relaxed atmosphere for in-depth discussion of theory, measurements, and applications. Furthermore, ELS-XV supported the United Nations "Year of Light" and celebrated the150th anniversary of Maxwell's electromagnetics. Maxwell's paper on "A Dynamical Theory of the Electromagnetic Field" was published in1865 and has widely been acknowledged as one of the supreme achievements in the history of science. The conference was attended by136 scientists from 22 countries. The scientific program included two plenary lectures, 16 invited reviews, 88 contributed oral talks, and 70 poster presentations. The program and the abstracts of conference presentations are available at the conference website http://www.els-xv-2015.net/home.html. Following the well-established ELS practice and with Elsevier's encouragement, we solicited full-size papers for a topical issue of the Journal of Quantitative Spectroscopy and Radiative Transfer (JQSRT). The result of this collective effort is now in the reader's hands. As always, every invited review and regular paper included in this topical issue has undergone the same rigorous peer review process as any other manuscript published in the JQSRT.

  20. Guiding-center Vlasov-Maxwell description of intense beam propagation through a periodic focusing field

    NASA Astrophysics Data System (ADS)

    Davidson, Ronald C.; Qin, Hong

    2001-10-01

    This paper provides a systematic derivation of a guiding-center kinetic model that describes intense beam propagation through a periodic focusing lattice with axial periodicity length S, valid for sufficiently small phase advance (say, σ<60°). The analysis assumes a thin \\(a,b<Maxwell equations that describe the slow evolution of the guiding-center distribution function f¯b\\(x¯,y¯,x¯',y¯',s\\) and (normalized) self-field potential ψ¯\\(x¯,y¯,s\\) in the four-dimensional transverse phase space \\(x¯,y¯,x¯',y¯'\\). In the resulting kinetic equation for f¯b\\(x¯,y¯,x¯',y¯',s\\), the average effects of the applied focusing field are incorporated in constant focusing coefficients κx sf>0 and κy sf>0, and the model is readily accessible to direct analytical investigation. Similar smooth-focusing Vlasov-Maxwell descriptions are widely used in the accelerator physics literature, often without a systematic justification, and the present analysis is intended to place these models on a rigorous, yet physically intuitive, foundation.

  1. Time-filtered leapfrog integration of Maxwell equations using unstaggered temporal grids

    NASA Astrophysics Data System (ADS)

    Mahalov, A.; Moustaoui, M.

    2016-11-01

    A finite-difference time-domain method for integration of Maxwell equations is presented. The computational algorithm is based on the leapfrog time stepping scheme with unstaggered temporal grids. It uses a fourth-order implicit time filter that reduces computational modes and fourth-order finite difference approximations for spatial derivatives. The method can be applied within both staggered and collocated spatial grids. It has the advantage of allowing explicit treatment of terms involving electric current density and application of selective numerical smoothing which can be used to smooth out errors generated by finite differencing. In addition, the method does not require iteration of the electric constitutive relation in nonlinear electromagnetic propagation problems. The numerical method is shown to be effective and stable when employed within Perfectly Matched Layers (PML). Stability analysis demonstrates that the proposed method is effective in stabilizing and controlling numerical instabilities of computational modes arising in wave propagation problems with physical damping and artificial smoothing terms while maintaining higher accuracy for the physical modes. Comparison of simulation results obtained from the proposed method and those computed by the classical time filtered leapfrog, where Maxwell equations are integrated for a lossy medium, within PML regions and for Kerr-nonlinear media show that the proposed method is robust and accurate. The performance of the computational algorithm is also verified by analyzing parametric four wave mixing in an optical nonlinear Kerr medium. The algorithm is found to accurately predict frequencies and amplitudes of nonlinearly converted waves under realistic conditions proposed in the literature.

  2. Vlasov-Maxwell and Vlasov-Poisson equations as models of a one-dimensional electron plasma

    NASA Technical Reports Server (NTRS)

    Klimas, A. J.; Cooper, J.

    1983-01-01

    The Vlasov-Maxwell and Vlasov-Poisson systems of equations for a one-dimensional electron plasma are defined and discussed. A method for transforming a solution of one system which is periodic over a bounded or unbounded spatial interval to a similar solution of the other is constructed.

  3. Direct time integration of Maxwell's equations in two-dimensional dielectric waveguides for propagation and scattering of femtosecond electromagnetic solitons

    NASA Technical Reports Server (NTRS)

    Joseph, Rose M.; Goorijan, Peter M.; Taflove, Allen

    1993-01-01

    Solution of 2D vector nonlinear Maxwell's equations is described for material media with linear and nonlinear instantaneous and Lorentz dispersion effects in the electric polarization. Finite difference time domain method is used in the analysis. The method discussed here achieves robustness by enforcing vector-field boundary conditions at all interfaces of dissimilar media.

  4. Hydrodynamics with conserved current via AdS/CFT correspondence in the Maxwell-Gauss-Bonnet gravity

    SciTech Connect

    Hu Yapeng; Sun Peng; Zhang Jianhui

    2011-06-15

    Using the AdS/CFT correspondence, we study the hydrodynamics with conserved current from the dual Maxwell-Gauss-Bonnet gravity. After constructing the perturbative solution to the first order based on the boosted black brane solution in the bulk Maxwell-Gauss-Bonnet gravity, we extract the stress tensor and conserved current of the dual conformal fluid on its boundary, and also find the effect of the Gauss-Bonnet term on the dual conformal fluid. Our results show that the Gauss-Bonnet term can affect the parameters such as the shear viscosity {eta}, entropy density s, thermal conductivity {kappa} and electrical conductivity {sigma}. However, it does not affect the so-called Wiedemann-Franz law which relates {kappa} to {sigma}, while it affects the ratio {eta}/s. In addition, another interesting result is that {eta}/s can also be affected by the bulk Maxwell field in our case, which is consistent with some previous results predicted through the Kubo formula. Moreover, the anomalous magnetic and vortical effects by adding the Chern-Simons term are also considered in our case in the Maxwell-Gauss-Bonnet gravity.

  5. Asymptotic-Preserving Particle-In-Cell methods for the Vlasov-Maxwell system in the quasi-neutral limit

    NASA Astrophysics Data System (ADS)

    Degond, P.; Deluzet, F.; Doyen, D.

    2017-02-01

    In this article, we design Asymptotic-Preserving Particle-In-Cell methods for the Vlasov-Maxwell system in the quasi-neutral limit, this limit being characterized by a Debye length negligible compared to the space scale of the problem. These methods are consistent discretizations of the Vlasov-Maxwell system which, in the quasi-neutral limit, remain stable and are consistent with a quasi-neutral model (in this quasi-neutral model, the electric field is computed by means of a generalized Ohm law). The derivation of Asymptotic-Preserving methods is not straightforward since the quasi-neutral model is a singular limit of the Vlasov-Maxwell model. The key step is a reformulation of the Vlasov-Maxwell system which unifies the two models in a single set of equations with a smooth transition from one to another. As demonstrated in various and demanding numerical simulations, the Asymptotic-Preserving methods are able to treat efficiently both quasi-neutral plasmas and non-neutral plasmas, making them particularly well suited for complex problems involving dense plasmas with localized non-neutral regions.

  6. Statistics Poker: Reinforcing Basic Statistical Concepts

    ERIC Educational Resources Information Center

    Leech, Nancy L.

    2008-01-01

    Learning basic statistical concepts does not need to be tedious or dry; it can be fun and interesting through cooperative learning in the small-group activity of Statistics Poker. This article describes a teaching approach for reinforcing basic statistical concepts that can help students who have high anxiety and makes learning and reinforcing…

  7. Predict! Teaching Statistics Using Informational Statistical Inference

    ERIC Educational Resources Information Center

    Makar, Katie

    2013-01-01

    Statistics is one of the most widely used topics for everyday life in the school mathematics curriculum. Unfortunately, the statistics taught in schools focuses on calculations and procedures before students have a chance to see it as a useful and powerful tool. Researchers have found that a dominant view of statistics is as an assortment of tools…

  8. A continuity-preserving and divergence-cleaning algorithm based on purely and damped hyperbolic Maxwell equations in inhomogeneous media

    NASA Astrophysics Data System (ADS)

    Yan, Su; Jin, Jian-Ming

    2017-04-01

    In the numerical solution of Maxwell's equations for dynamic electromagnetic fields, the two Gauss's laws are usually not considered since they are a natural consequence of Faraday's and Maxwell-Ampère's laws if the charge conservation law is satisfied. However, when the charge conservation law is not satisfied, the numerical errors of Gauss's laws will increase unbounded, leading to numerical instability or breakdown. Unfortunately, the charge conservation law can be easily violated in self-consistent wave-particle simulations. In the meantime, the violation of Gauss's laws will also result in an increased error in the normal flux continuity. In the simulations of pure electromagnetic problems, the satisfaction of tangential field continuity across a material interface is sufficient to yield accurate numerical results. However, in a self-consistent wave-particle simulation, the normal components are as important as the tangential components, since they are critical in predicting the particle kinetics. In this paper, a divergence-cleaning method is presented to enforce Gauss's laws and normal flux continuity by introducing auxiliary variables and damping terms into Maxwell's equations in inhomogeneous media, which yield hyperbolic and mixed hyperbolic-parabolic Maxwell equations. The numerical solution schemes of the resulting purely and damped hyperbolic Maxwell equations are introduced under the framework of the discontinuous Galerkin time-domain method. It is shown through several numerical examples that the proposed method is able to preserve the continuity conditions for both tangential field components and normal flux components, and is effective in cleaning the numerical errors in both Gauss's laws.

  9. Thermodynamics and statistical mechanics. [thermodynamic properties of gases

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The basic thermodynamic properties of gases are reviewed and the relations between them are derived from the first and second laws. The elements of statistical mechanics are then formulated and the partition function is derived. The classical form of the partition function is used to obtain the Maxwell-Boltzmann distribution of kinetic energies in the gas phase and the equipartition of energy theorem is given in its most general form. The thermodynamic properties are all derived as functions of the partition function. Quantum statistics are reviewed briefly and the differences between the Boltzmann distribution function for classical particles and the Fermi-Dirac and Bose-Einstein distributions for quantum particles are discussed.

  10. The development of ensemble theory. A new glimpse at the history of statistical mechanics

    NASA Astrophysics Data System (ADS)

    Inaba, Hajime

    2015-12-01

    This paper investigates the history of statistical mechanics from the viewpoint of the development of the ensemble theory from 1871 to 1902. In 1871, Ludwig Boltzmann introduced a prototype model of an ensemble that represents a polyatomic gas. In 1879, James Clerk Maxwell defined an ensemble as copies of systems of the same energy. Inspired by H.W. Watson, he called his approach "statistical". Boltzmann and Maxwell regarded the ensemble theory as a much more general approach than the kinetic theory. In the 1880s, influenced by Hermann von Helmholtz, Boltzmann made use of ensembles to establish thermodynamic relations. In Elementary Principles in Statistical Mechanics of 1902, Josiah Willard Gibbs tried to get his ensemble theory to mirror thermodynamics, including thermodynamic operations in its scope. Thermodynamics played the role of a "blind guide". His theory of ensembles can be characterized as more mathematically oriented than Einstein's theory proposed in the same year. Mechanical, empirical, and statistical approaches to foundations of statistical mechanics are presented. Although it was formulated in classical terms, the ensemble theory provided an infrastructure still valuable in quantum statistics because of its generality.

  11. Quantum statistics of classical particles derived from the condition of a free diffusion coefficient

    NASA Astrophysics Data System (ADS)

    Hoyuelos, M.; Sisterna, P.

    2016-12-01

    We derive an equation for the current of particles in energy space; particles are subject to a mean-field effective potential that may represent quantum effects. From the assumption that noninteracting particles imply a free diffusion coefficient in energy space, we derive Maxwell-Boltzmann, Fermi-Dirac, and Bose-Einstein statistics. Other new statistics are associated to a free diffusion coefficient; their thermodynamic properties are analyzed using the grand partition function. A negative relation between pressure and energy density for low temperatures can be derived, suggesting a possible connection with cosmological dark energy models.

  12. Neuroendocrine Tumor: Statistics

    MedlinePlus

    ... Tumor > Neuroendocrine Tumor: Statistics Request Permissions Neuroendocrine Tumor: Statistics Approved by the Cancer.Net Editorial Board , 11/ ... the body. It is important to remember that statistics on how many people survive this type of ...

  13. Adrenal Gland Tumors: Statistics

    MedlinePlus

    ... Gland Tumor: Statistics Request Permissions Adrenal Gland Tumor: Statistics Approved by the Cancer.Net Editorial Board , 03/ ... primary adrenal gland tumor is very uncommon. Exact statistics are not available for this type of tumor ...

  14. Development and application of discontinuous Galerkin method for the solution of two-dimensional Maxwell equations

    NASA Astrophysics Data System (ADS)

    Wong, See-Cheuk

    We inhabit an environment of electromagnetic (EM) waves. The waves within the EM spectrum---whether light, radio, or microwaves---all obey the same physical laws. A band in the spectrum is designated to the microwave frequencies (30MHz--300GHz), at which radar systems operate. The precise modeling of the scattered EM-ields about a target, as well as the numerical prediction of the radar return is the crux of the computational electromagnetics (CEM) problems. The signature or return from a target observed by radar is commonly provided in the form of radar cross section (RCS). Incidentally, the efforts in the reduction of such return forms the basis of stealth aircraft design. The object of this dissertation is to extend Discontinuous Galerkin (DG) method to solve numerically the Maxwell equations for scatterings from perfect electric conductor (PEC) objects. The governing equations are derived by writing the Maxwell equations in conservation-law form for scattered field quantities. The transverse magnetic (TM) and the transverse electric (TE) waveforms of the Maxwell equations are considered. A finite-element scheme is developed with proper representations for the electric and magnetic fluxes at a cell interface to account for variations in properties, in both space and time. A characteristic sub-path integration process, known as the "Riemann solver" is involved. An explicit Runge-Kutta Discontinuous Galerkin (RKDG) upwind scheme, which is fourth-order accurate in time and second-order in space, is employed to solve the TM and TE equations. Arbitrary cross-sectioned bodies are modeled, around which computational grids using random triangulation are generated. The RKDG method, in its development stage, was constructed and studied for solving hyperbolic conservation equations numerically. It was later extended to multidimensional nonlinear systems of conservation laws. The algorithms are described, including the formulations and treatments to the numerical fluxes

  15. PROBABILITY AND STATISTICS.

    DTIC Science & Technology

    STATISTICAL ANALYSIS, REPORTS), (*PROBABILITY, REPORTS), INFORMATION THEORY, DIFFERENTIAL EQUATIONS, STATISTICAL PROCESSES, STOCHASTIC PROCESSES, MULTIVARIATE ANALYSIS, DISTRIBUTION THEORY , DECISION THEORY, MEASURE THEORY, OPTIMIZATION

  16. Three-Dimensional High-Order Spectral Volume Method for Solving Maxwell's Equations on Unstructured Grids

    NASA Technical Reports Server (NTRS)

    Liu, Yen; Vinokur, Marcel; Wang, Z. J.

    2004-01-01

    A three-dimensional, high-order, conservative, and efficient discontinuous spectral volume (SV) method for the solutions of Maxwell's equations on unstructured grids is presented. The concept of discontinuous 2nd high-order loca1 representations to achieve conservation and high accuracy is utilized in a manner similar to the Discontinuous Galerkin (DG) method, but instead of using a Galerkin finite-element formulation, the SV method is based on a finite-volume approach to attain a simpler formulation. Conventional unstructured finite-volume methods require data reconstruction based on the least-squares formulation using neighboring cell data. Since each unknown employs a different stencil, one must repeat the least-squares inversion for every cell at each time step, or to store the inversion coefficients. In a high-order, three-dimensional computation, the former would involve impractically large CPU time, while for the latter the memory requirement becomes prohibitive. In the SV method, one starts with a relatively coarse grid of triangles or tetrahedra, called spectral volumes (SVs), and partition each SV into a number of structured subcells, called control volumes (CVs), that support a polynomial expansion of a desired degree of precision. The unknowns are cell averages over CVs. If all the SVs are partitioned in a geometrically similar manner, the reconstruction becomes universal as a weighted sum of unknowns, and only a few universal coefficients need to be stored for the surface integrals over CV faces. Since the solution is discontinuous across the SV boundaries, a Riemann solver is thus necessary to maintain conservation. In the paper, multi-parameter and symmetric SV partitions, up to quartic for triangle and cubic for tetrahedron, are first presented. The corresponding weight coefficients for CV face integrals in terms of CV cell averages for each partition are analytically determined. These discretization formulas are then applied to the integral form of

  17. Handbook of the Statistics of Various Terrain and Water (Ice) Backgrounds from Selected U.S. Locations

    DTIC Science & Technology

    1980-01-01

    operations necessary for the successful completion of the analyses. Dr. J. Robert Maxwell was the initial Project Manager and has contributed invaluably to...the histograms provide estimates of how the detection probability and false alarm rate vary with threshold setting. However, today there is a nee.d for...alarm rates V iwith today’s sensor and processor technology. The statistics developed are the probabilities that regions (of various sizes, shapes, and

  18. Statistical Reference Datasets

    National Institute of Standards and Technology Data Gateway

    Statistical Reference Datasets (Web, free access)   The Statistical Reference Datasets is also supported by the Standard Reference Data Program. The purpose of this project is to improve the accuracy of statistical software by providing reference datasets with certified computational results that enable the objective evaluation of statistical software.

  19. Explorations in statistics: statistical facets of reproducibility.

    PubMed

    Curran-Everett, Douglas

    2016-06-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This eleventh installment of Explorations in Statistics explores statistical facets of reproducibility. If we obtain an experimental result that is scientifically meaningful and statistically unusual, we would like to know that our result reflects a general biological phenomenon that another researcher could reproduce if (s)he repeated our experiment. But more often than not, we may learn this researcher cannot replicate our result. The National Institutes of Health and the Federation of American Societies for Experimental Biology have created training modules and outlined strategies to help improve the reproducibility of research. These particular approaches are necessary, but they are not sufficient. The principles of hypothesis testing and estimation are inherent to the notion of reproducibility in science. If we want to improve the reproducibility of our research, then we need to rethink how we apply fundamental concepts of statistics to our science.

  20. Observing the shadow of Einstein-Maxwell-Dilaton-Axion black hole

    SciTech Connect

    Wei, Shao-Wen; Liu, Yu-Xiao E-mail: liuyx@lzu.edu.cn

    2013-11-01

    In this paper, the shadows cast by Einstein-Maxwell-Dilaton-Axion black hole and naked singularity are studied. The shadow of a rotating black hole is found to be a dark zone covered by a deformed circle. For a fixed value of the spin a, the size of the shadow decreases with the dilaton parameter b. The distortion of the shadow monotonically increases with b and takes its maximal when the black hole approaches to the extremal case. Due to the optical properties, the area of the black hole shadow is supposed to equal to the high-energy absorption cross section. Based on this assumption, the energy emission rate is investigated. For a naked singularity, the shadow has a dark arc and a dark spot or straight, and the corresponding observables are obtained. These results show that there is a significant effect of the spin a and dilaton parameter b on these shadows. Moreover, we examine the observables of the shadow cast by the supermassive black hole at the center of the Milky Way, which is very useful for us to probe the nature of the black hole through the astronomical observations in the near future.

  1. A universal framework for non-deteriorating time-domain numerical algorithms in Maxwell's electrodynamics

    NASA Astrophysics Data System (ADS)

    Fedoseyev, A.; Kansa, E. J.; Tsynkov, S.; Petropavlovskiy, S.; Osintcev, M.; Shumlak, U.; Henshaw, W. D.

    2016-10-01

    We present the implementation of the Lacuna method, that removes a key diffculty that currently hampers many existing methods for computing unsteady electromagnetic waves on unbounded regions. Numerical accuracy and/or stability may deterio-rate over long times due to the treatment of artificial outer boundaries. We describe a developed universal algorithm and software that correct this problem by employing the Huygens' principle and lacunae of Maxwell's equations. The algorithm provides a temporally uniform guaranteed error bound (no deterioration at all), and the software will enable robust electromagnetic simulations in a high-performance computing environment. The methodology applies to any geometry, any scheme, and any boundary condition. It eliminates the long-time deterioration regardless of its origin and how it manifests itself. In retrospect, the lacunae method was first proposed by V. Ryaben'kii and subsequently developed by S. Tsynkov. We have completed development of an innovative numerical methodology for high fidelity error-controlled modeling of a broad variety of electromagnetic and other wave phenomena. Proof-of-concept 3D computations have been conducted that con-vincingly demonstrate the feasibility and effciency of the proposed approach. Our algorithms are being implemented as robust commercial software tools in a standalone module to be combined with existing numerical schemes in several widely used computational electromagnetic codes.

  2. Maxwell-Wagner polarization and frequency-dependent injection at aqueous electrical interfaces.

    PubMed

    Desmond, Mitchell; Mavrogiannis, Nicholas; Gagnon, Zachary

    2012-11-02

    We demonstrate a new type of alternating current (ac) interfacial polarization and frequency-dependent fluid displacement phenomenon at a liquid-liquid electrical interface. Two fluid streams--one with a greater electrical conductivity and the other a greater dielectric constant--are made to flow side by side in a microfluidic channel. An ac electric field is applied perpendicular to the interface formed between the liquid lamellae, and fluid is observed to displace across the liquid-liquid interface. The direction and magnitude of this displacement is frequency dependent. At low ac frequency, below the interfacial inverse charge relaxation time, the high-conductivity fluid displaces into the high-dielectric stream. At high frequency the direction of liquid displacement reverses, and the high-dielectric stream injects into the high-conductivity stream. The interfacial crossover frequency where the liquid displacement direction reverses is dependent on differences in electrical properties between the two fluid streams, and is well explained by Maxwell-Wagner polarization mechanics.

  3. Reissner-Nordstrom-anti-de Sitter nontopological solitons in broken Einstein-Maxwell-Higgs theory

    NASA Astrophysics Data System (ADS)

    Honda, Ethan

    2017-01-01

    Results are presented from numerical simulations of the Einstein-Maxwell-Higgs equations with a broken U(1) symmetry. Coherent nontopological soliton solutions are shown to exist that separate an anti-de Sitter (AdS) true vacuum interior from a Reissner-Nordstrom (RN) false vacuum exterior. The stability of these bubble solutions is tested by perturbing the charge of the coherent solution and evolving the time-dependent equations of motion. In the weak gravitational limit, the short-term stability depends on the sign of (ω /Q )∂ωQ , similar to Q -balls. The long-term end state of the perturbed solutions demonstrates a rich structure and is visualized using "phase diagrams." Regions of both stability and instability are shown to exist for κg≲0.015 , while solutions with κg≳0.015 were observed to be entirely unstable. Threshold solutions are shown to demonstrate time-scaling laws, and the space separating true and false vacuum end states is shown to be fractal in nature, similar to oscillons. Coherent states with superextremal charge-to-mass ratios are shown to exist and observed to collapse or expand, depending on the sign of the charge perturbation. Expanding superextremal bubbles induce phase transitions to the true AdS vacuum, while collapsing superextremal bubbles can form nonsingular strongly gravitating solutions with superextremal RN exteriors.

  4. Complete spin and orbital evolution of close-in bodies using a Maxwell viscoelastic rheology

    NASA Astrophysics Data System (ADS)

    Boué, Gwenaël; Correia, Alexandre C. M.; Laskar, Jacques

    2016-11-01

    In this paper, we present a formalism designed to model tidal interaction with a viscoelastic body made of Maxwell material. Our approach remains regular for any spin rate and orientation, and for any orbital configuration including high eccentricities and close encounters. The method is to integrate simultaneously the rotation and the position of the planet as well as its deformation. We provide the equations of motion both in the body frame and in the inertial frame. With this study, we generalize preexisting models to the spatial case and to arbitrary multipole orders using a formalism taken from quantum theory. We also provide the vectorial expression of the secular tidal torque expanded in Fourier series. Applying this model to close-in exoplanets, we observe that if the relaxation time is longer than the revolution period, the phase space of the system is characterized by the presence of several spin-orbit resonances, even in the circular case. As the system evolves, the planet spin can visit different spin-orbit configurations. The obliquity is decreasing along most of these resonances, but we observe a case where the planet tilt is instead growing. These conclusions derived from the secular torque are successfully tested with numerical integrations of the instantaneous equations of motion on HD 80606 b. Our formalism is also well adapted to close-in super-Earths in multiplanet systems which are known to have non-zero mutual inclinations.

  5. Dynamical Casimir effect in a small compact manifold for the Maxwell vacuum

    NASA Astrophysics Data System (ADS)

    Zhitnitsky, Ariel R.

    2015-05-01

    We study a novel type of contribution to the partition function of the Maxwell system defined on a small compact manifold M such as a torus. These new terms cannot be described in terms of the physical propagating photons with two transverse polarizations. Rather, these novel contributions emerge as a result of tunneling events when transitions occur between topologically different but physically identical vacuum winding states. These new terms give an extra contribution to the Casimir pressure, yet to be measured. We argue that if the same system is considered in the background of a small external time-dependent magnetic field, then there will be emission of photons from the vacuum, similar to the dynamical Casimir effect (DCE) when real particles are radiated from the vacuum due to the time-dependent boundary conditions. The difference with conventional DCE is that the dynamics of the vacuum in our system is not related to the fluctuations of the conventional degrees of freedom, the virtual photons. Rather, the radiation in our case occurs as a result of tunneling events between topologically different but physically identical |k ⟩ sectors in a time-dependent background. We comment on the relation of this novel effect to the well-known, experimentally observed, and theoretically understood phenomena of the persistent currents in normal metal rings. We also comment on possible cosmological applications of this effect.

  6. Fast Solutions of Maxwell's Equation for High Resolution Electromagnetic Imaging of Transport Pathways

    SciTech Connect

    DAY,DAVID M.; NEWMAN,GREGORY A.

    1999-10-01

    A fast precondition technique has been developed which accelerates the finite difference solutions of the 3D Maxwell's equations for geophysical modeling. The technique splits the electric field into its curl free and divergence free projections, and allows for the construction of an inverse operator. Test examples show an order of magnitude speed up compared with a simple Jacobi preconditioner. Using this preconditioner a low frequency Neumann series expansion is developed and used to compute responses at multiple frequencies very efficiently. Simulations requiring responses at multiple frequencies, show that the Neumann series is faster than the preconditioned solution, which must compute solutions at each discrete frequency. A Neumann series expansion has also been developed in the high frequency limit along with spectral Lanczos methods in both the high and low frequency cases for simulating multiple frequency responses with maximum efficiency. The research described in this report was to have been carried out over a two-year period. Because of communication difficulties, the project was funded for first year only. Thus the contents of this report are incomplete with respect to the original project objectives.

  7. Spatial contraction of the Poincare group and Maxwell's equations in the electric limit

    SciTech Connect

    Reich, H.T. Wickramasekara, S.

    2010-05-15

    The contraction of the Poincare group with respect to the space translations subgroup gives rise to a group that bears a certain duality relation to the Galilei group, that is, the contraction limit of the Poincare group with respect to the time translations subgroup. In view of this duality, we call the former the dual Galilei group. A rather remarkable feature of the dual Galilei group is that the time translations constitute a central subgroup. Therewith, in unitary irreducible representations (UIRs) of the group, the Hamiltonian appears as a Casimir operator proportional to the identity H = EI, with E (and a spin value s) uniquely characterizing the representation. Hence, a physical system characterized by a UIR of the dual Galilei group displays no non-trivial time evolution. Moreover, the combined U(1) gauge group and the dual Galilei group underlie a non-relativistic limit of Maxwell's equations known as the electric limit. The analysis presented here shows that only electrostatics is possible for the electric limit, wholly in harmony with the trivial nature of time evolution governed by the dual Galilei group.

  8. New spectral line multibeam correlator system for the James Clerk Maxwell Telescope

    NASA Astrophysics Data System (ADS)

    Hovey, Gary J.; Burgess, Thomas A.; Casorso, Ronald V.; Dent, William R.; Dewdney, Peter E.; Force, Brian; Lightfoot, John F.; Willis, Anthony G.; Yeung, Keith K.

    2000-07-01

    A new Auto-Correlation Spectral Imaging System (ACSIS) for the James Clerk Maxwell Telescope (JCMT) is being developed at the National Research Council of Canada, in collaboration with the Joint Astronomy Centre and the United Kingdom Astronomy Technology Centre. The system is capable of computing the integrated power-spectra over 1-GHz bandwidths for up to 32 receiver beams every 50 ms. An innovative, multiprocessor computer will produce calibrated, gridded, 3-D data cubes so that they can be viewed in real-time and are in hand when an observation is over. When connected to arrays of receivers at the Nasmyth focus of the telescope, the system will be able to rapidly make large-scale images with high spectral resolution and map multiple transitions. The ACSIS system will be mated initially with the multibeam 350-GHz receiver system. Heterodyne ARray Program (HARP), under development at the Mullard Radio Astronomy Observatory in Cambridge, England. In this paper we describe ACSIS, how it is designed and the results of key performance tests made.

  9. On numerical methods for Hamiltonian PDEs and a collocation method for the Vlasov-Maxwell equations

    SciTech Connect

    Holloway, J.P.

    1996-11-01

    Hamiltonian partial differential equations often have implicit conservation laws-constants of the motion-embedded within them. It is not, in general, possible to preserve these conservation laws simply by discretization in conservative form because there is frequently only one explicit conservation law. However, by using weighted residual methods and exploiting the Hamiltonian structure of the equations it is shown that at least some of the conservation laws are preserved in a method of lines (continuous in time). In particular, the Hamiltonian can always be exactly preserved as a constant of the motion. Other conservation laws, in particular linear and quadratic Casimirs and momenta, can sometimes be conserved too, depending on the details of the equations under consideration and the form of discretization employed. Collocation methods also offer automatic conservation of linear and quadratic Casimirs. Some standard discretization methods, when applied to Hamiltonian problems are shown to be derived from a numerical approximation to the exact Poisson bracket of the system. A method for the Vlasov-Maxwell equations based on Legendre-Gauss-Lobatto collocation is presented as an example of these ideas. 22 refs.

  10. A Fourth Order Difference Scheme for the Maxwell Equations on Yee Grid

    SciTech Connect

    Fathy, Aly E; Wilson, Joshua L

    2008-09-01

    The Maxwell equations are solved by a long-stencil fourth order finite difference method over a Yee grid, in which different physical variables are located at staggered mesh points. A careful treatment of the numerical values near the boundary is introduced, which in turn leads to a 'symmetric image' formula at the 'ghost' grid points. Such a symmetric formula assures the stability of the boundary extrapolation. In turn, the fourth order discrete curl operator for the electric and magnetic vectors gives a complete set of eigenvalues in the purely imaginary axis. To advance the dynamic equations, the four-stage Runge-Kutta method is utilized, which results in a full fourth order accuracy in both time and space. A stability constraint for the time step is formulated at both the theoretical and numerical levels, using an argument of stability domain. An accuracy check is presented to verify the fourth order precision, using a comparison between exact solution and numerical solutions at a fixed final time. In addition, some numerical simulations of a loss-less rectangular cavity are also carried out and the frequency is measured precisely.

  11. Electric hyperscaling violating solutions in Einstein-Maxwell-dilaton gravity with R2 corrections

    NASA Astrophysics Data System (ADS)

    O'Keeffe, Daniel K.; Peet, Amanda W.

    2014-07-01

    In the context of holography applied to condensed matter physics, we study Einstein-Maxwell-dilaton theory with curvature squared corrections. This theory has three couplings ηi for the three R2 invariants and two theory functions: a dilaton potential V(ϕ) and a dilaton-dependent gauge coupling f(ϕ). We find hyperscaling violating (HSV) solutions of this theory, parametrized by dynamical critical exponent z and HSV parameter θ. We obtain restrictions on the form of the theory functions required to support HSV-type solutions using three physical inputs: the null energy condition, causality z≥1, and deff≡d-θ lying in the range 0

  12. Maxwell-Dirac stress-energy tensor in terms of Fierz bilinear currents

    NASA Astrophysics Data System (ADS)

    Inglis, Shaun; Jarvis, Peter

    2016-03-01

    We analyse the stress-energy tensor for the self-coupled Maxwell-Dirac system in the bilinear current formalism, using two independent approaches. The first method used is that attributed to Belinfante: starting from the spinor form of the action, the well-known canonical stress-energy tensor is augmented, by extending the Noether symmetry current to include contributions from the Lorentz group, to a manifestly symmetric form. This form admits a transcription to bilinear current form. The second method used is the variational derivation based on the covariant coupling to general relativity. The starting point here at the outset is the transcription of the action using, as independent field variables, both the bilinear currents, together with a gauge invariant vector field (a proxy for the electromagnetic vector potential). A central feature of the two constructions is that they both involve the mapping of the Dirac contribution to the stress-energy from the spinor fields to the equivalent set of bilinear tensor currents, through the use of appropriate Fierz identities. Although this mapping is done at quite different stages, nonetheless we find that the two forms of the bilinear stress-energy tensor agree. Finally, as an application, we consider the reduction of the obtained stress-energy tensor in bilinear form, under the assumption of spherical symmetry.

  13. Density functional theory: Non-Born-Oppenheimer Legendre transforms and Maxwell relations, equilibrium and stability conditions

    NASA Astrophysics Data System (ADS)

    Nalewajski, Roman F.; Capitani, Joseph F.

    1982-09-01

    The Legendre-transformed representations of the non-Born-Oppenheimer (NBO) density functional theory are analyzed and the corresponding Maxwell relations are derived. These relations exhibit various couplings between parameters of the NBO ground-state energy hypersurfaces: ɛ[{Ni, Zi, Mi}] and ɛφ[{Ni, Zi, Mi},φ], where Ni, Zi, and Mi denote, respectively, the number of particles i, their charge and mass, while φ stands for an external electric field. The criteria for intrinsic equilibrium and stability of molecular systems are formulated and discussed within both the BO and NBO approximations. The physical content of stability criteria is interpreted in terms of the Le Châtelier and the Le Châtelier-Braun principles. The classical nature of these criteria is revealed through the introduction of internal partial scalar pressures of the system components (groups of identical particles) within the local formulation of the theory. It is then shown that the criteria of equilibrium and stability in isolated molecular systems become the classical criteria of the ''mechanical''-electrostatic equilibrium and stability.

  14. Electrical Maxwell demon and Szilard engine utilizing Johnson noise, measurement, logic and control.

    PubMed

    Kish, Laszlo Bela; Granqvist, Claes-Göran

    2012-01-01

    We introduce a purely electrical version of Maxwell's demon which does not involve mechanically moving parts such as trapdoors, etc. It consists of a capacitor, resistors, amplifiers, logic circuitry and electronically controlled switches and uses thermal noise in resistors (Johnson noise) to pump heat. The only types of energy of importance in this demon are electrical energy and heat. We also demonstrate an entirely electrical version of Szilard's engine, i.e., an information-controlled device that can produce work by employing thermal fluctuations. The only moving part is a piston that executes work, and the engine has purely electronic controls and it is free of the major weakness of the original Szilard engine in not requiring removal and repositioning the piston at the end of the cycle. For both devices, the energy dissipation in the memory and other binary informatics components are insignificant compared to the exponentially large energy dissipation in the analog part responsible for creating new information by measurement and decision. This result contradicts the view that the energy dissipation in the memory during erasure is the most essential dissipation process in a demon. Nevertheless the dissipation in the memory and information processing parts is sufficient to secure the Second Law of Thermodynamics.

  15. Electrical Maxwell Demon and Szilard Engine Utilizing Johnson Noise, Measurement, Logic and Control

    PubMed Central

    Kish, Laszlo Bela; Granqvist, Claes-Göran

    2012-01-01

    We introduce a purely electrical version of Maxwell's demon which does not involve mechanically moving parts such as trapdoors, etc. It consists of a capacitor, resistors, amplifiers, logic circuitry and electronically controlled switches and uses thermal noise in resistors (Johnson noise) to pump heat. The only types of energy of importance in this demon are electrical energy and heat. We also demonstrate an entirely electrical version of Szilard's engine, i.e., an information-controlled device that can produce work by employing thermal fluctuations. The only moving part is a piston that executes work, and the engine has purely electronic controls and it is free of the major weakness of the original Szilard engine in not requiring removal and repositioning the piston at the end of the cycle. For both devices, the energy dissipation in the memory and other binary informatics components are insignificant compared to the exponentially large energy dissipation in the analog part responsible for creating new information by measurement and decision. This result contradicts the view that the energy dissipation in the memory during erasure is the most essential dissipation process in a demon. Nevertheless the dissipation in the memory and information processing parts is sufficient to secure the Second Law of Thermodynamics. PMID:23077525

  16. Rogue waves of the Hirota and the Maxwell-Bloch equations.

    PubMed

    Li, Chuanzhong; He, Jingsong; Porsezian, K; Porseizan, K

    2013-01-01

    In this paper, we derive a Darboux transformation of the Hirota and the Maxwell-Bloch (H-MB) system which is governed by femtosecond pulse propagation through an erbium doped fiber and further generalize it to the matrix form of the n-fold Darboux transformation of this system. This n-fold Darboux transformation implies the determinant representation of nth solutions of (E([n]),p([n]),η([n])) generated from the known solution of (E,p,η). The determinant representation of (E([n]),p([n]),η([n])) provides soliton solutions, positon solutions, and breather solutions (both bright and dark breathers) of the H-MB system. From the breather solutions, we also construct a bright and dark rogue wave solution for the H-MB system, which is currently one of the hottest topics in mathematics and physics. Surprisingly, the rogue wave solution for p and η has two peaks because of the order of the numerator and denominator of them. Meanwhile, after fixing the time and spatial parameters and changing two other unknown parameters α and β, we generate a rogue wave shape.

  17. Small polaronic hole hopping mechanism and Maxwell-Wagner relaxation in NdFeO3

    NASA Astrophysics Data System (ADS)

    Ahmad, I.; Akhtar, M. J.; Younas, M.; Siddique, M.; Hasan, M. M.

    2012-10-01

    In the modern micro-electronics, transition metal oxides due to their colossal values of dielectric permittivity possess huge potential for the development of capacitive energy storage devices. In the present work, the dielectric permittivity and the effects of temperature and frequency on the electrical transport properties of polycrystalline NdFeO3, prepared by solid state reaction method, are discussed. Room temperature Mossbauer spectrum confirms the phase purity, octahedral environment for Fe ion, and high spin state of Fe3+ ion. From the impedance spectroscopic measurements, three relaxation processes are observed, which are related to grains, grain boundaries (gbs), and electrode-semiconductor contact in the measured temperature and frequency ranges. Decrease in resistances and relaxation times of the grains and grain boundaries with temperature confirms the involvement of thermally activated conduction mechanisms. Same type of charge carriers (i.e., small polaron hole hopping) have been found responsible for conduction and relaxation processes through the grain and grain boundaries. The huge value of the dielectric constant (˜8 × 103) at high temperature and low frequency is correlated to the Maxwell-Wagner relaxation due to electrode-sample contact.

  18. Charged rotating black holes in Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant

    NASA Astrophysics Data System (ADS)

    Blázquez-Salcedo, Jose Luis; Kunz, Jutta; Navarro-Lérida, Francisco; Radu, Eugen

    2017-03-01

    We consider rotating black hole solutions in five-dimensional Einstein-Maxwell-Chern-Simons theory with a negative cosmological constant and a generic value of the Chern-Simons coupling constant λ . Using both analytical and numerical techniques, we focus on cohomogeneity-1 configurations, with two equal-magnitude angular momenta, which approach at infinity a globally anti-de Sitter background. We find that the generic solutions share a number of basic properties with the known Cvetič, Lü, and Pope black holes which have λ =1 . New features occur as well; for example, when the Chern-Simons coupling constant exceeds a critical value, the solutions are no longer uniquely determined by their global charges. Moreover, the black holes possess radial excitations which can be labelled by the node number of the magnetic gauge potential function. Solutions with small values of λ possess other distinct features. For instance, the extremal black holes there form two disconnected branches, while not all near-horizon solutions are associated with global solutions.

  19. Maxwell stress to explain the mechanism for the anisotropic expansion in lithiated silicon nanowires

    NASA Astrophysics Data System (ADS)

    Boone, Donald C.

    2016-12-01

    This computational research study attempts to explain the process that leads to volume expansion during insertion of lithium ions into a silicon nanowire. During lithiation, electrons flow through the nanowire in the opposing direction of lithium ions insertion. This causes an applied electromagnetic field which is described as being a quantum mechanical version of photon density wave theory. A series of events are calculated as the individual electrons and photons travels through the lithiated silicon nanowire. The hypothesis that will be presented employs the Maxwell stress tensor to calculate the refractive indices in three orthogonal directions during lithiation. The quantum harmonic oscillator and the electromagnetic intensity will be utilized in this presentation to calculate the energy of electrons and optical amplification of the electromagnetic field respectively. The main focus of this research study will use electron scattering theory, spontaneous and stimulated emission theory to model the breaking of cohesion bonds between silicon atoms that ultimately leads to excessive volume expansion that is witnessed during the lithiation process in Si nanowires.

  20. Finite-difference algorithms for the time-domain Maxwell's equations - A numerical approach to RCS analysis

    NASA Technical Reports Server (NTRS)

    Vinh, Hoang; Dwyer, Harry A.; Van Dam, C. P.

    1992-01-01

    The applications of two CFD-based finite-difference methods to computational electromagnetics are investigated. In the first method, the time-domain Maxwell's equations are solved using the explicit Lax-Wendroff scheme and in the second method, the second-order wave equations satisfying the Maxwell's equations are solved using the implicit Crank-Nicolson scheme. The governing equations are transformed to a generalized curvilinear coordinate system and solved on a body-conforming mesh using the scattered-field formulation. The induced surface current and the bistatic radar cross section are computed and the results are validated for several two-dimensional test cases involving perfectly-conducting scatterers submerged in transverse-magnetic plane waves.

  1. Magnetic propulsion of a magnetic device using three square-Helmholtz coils and a square-Maxwell coil.

    PubMed

    Ha, Yong H; Han, Byung H; Lee, Soo Y

    2010-02-01

    We introduce a square coil system for remote magnetic navigation of a magnetic device without any physical movements of the coils. We used three square-Helmholtz coils and a square-Maxwell coil for magnetic propulsion of a small magnet along the desired path. All the square coils are mountable on a cubic frame that has an opening to accommodate a living subject. The square-Helmholtz coils control the magnetic propulsion direction by generating uniform magnetic field along the desired direction while the square-Maxwell coil controls the propulsion force by generating magnetic gradient field. We performed magnetic propulsion experiments with a down-scaled coil set and a three-channel coil driver. Experimental results demonstrate that we can use the square coil set for magnetic navigation of a magnetic device without any physical movements of the coils.

  2. GEMPIC: Geometric ElectroMagnetic Particle-In-Cell Methods for the Vlasov-Maxwell System and Gyrokinetics

    NASA Astrophysics Data System (ADS)

    Kraus, Michael; Kormann, Katharina; Sonnendrücker, Eric; Morrison, Philip

    2016-10-01

    In this talk we will describe recent work on the development of geometric particle-in-cell methods for the Vlasov-Maxwell system and gyrokinetics. We present a novel framework for particle-in-cell methods based on the discretization of the underlying Hamiltonian structure of the Vlasov-Maxwell system. We derive semi-discrete Poisson brackets which satisfy the Jacobi identity and apply Hamiltonian splitting schemes for time integration. Techniques from Finite Element Exterior Calculus and spline differential forms ensure conservation of the divergence of the magnetic field and Gauss' law as well as stability of the field solver. The resulting methods are gauge-invariant, feature exact charge conservation show excellent long-time energy behaviour. The talk will be concluded with an outline of how to extend these techniques towards gyrokinetics.

  3. Iran’s Strategic Culture and Weapons of Mass Destruction. Implications for US Policy (Maxwell Paper, Number 26)

    DTIC Science & Technology

    2002-04-01

    Khomeini dominated the government (1979-89), the combination of his charisma, his religious authority as imam , and a brutally efficient internal security...favored social reform founded upon Islamic values. Ayatollah Ruhollah Khomeini , the charismatic imam whose vitriolic sermons helped to polar- ize...Unlimited𔄀 ’ for US Policy i ~ Anthony C. Cain "y Lieutenant Colonel, USAF ( !Air War College Maxwell Paper No. 26 Air University Donald A. Lamontagne

  4. Black hole solution of Gauss-Bonnet massive gravity coupled to Maxwell and Yang-Mills fields in five dimensions

    NASA Astrophysics Data System (ADS)

    Meng, K.; Li, J.

    2016-10-01

    We construct a new static black hole solution of Gauss-Bonnet massive gravity coupled to Maxwell and Yang-Mills fields in five dimensions. We calculate the thermodynamical quantities of the black hole and check the first law of black hole thermodynamics. Thermal stability of the black hole is explored in the context of both canonical and grand canonical ensembles. By identifying the cosmological constant as the pressure of the gravitational system, we study the phase transitions of the black hole.

  5. Exact, zero-energy, square-integrable solutions of a model related to the Maxwell's fish-eye problem

    SciTech Connect

    Makowski, Adam J.

    2009-12-15

    A model, which admits normalizable wave functions of the Schroedinger equation at the energy of E = 0, is exactly solved and the solutions are compared to the corresponding classical trajectories. The wave functions are proved to be square-integrable for discrete (quantized) values of the coupling constant of the used potential. We also show that our model is a specific version of the well-known Maxwell's fish-eye. This is performed with the help of a suitably chosen conformal mapping.

  6. Hydromagnetic Steady Flow of Maxwell Fluid over a Bidirectional Stretching Surface with Prescribed Surface Temperature and Prescribed Surface Heat Flux

    PubMed Central

    Shehzad, Sabir Ali; Alsaedi, Ahmad; Hayat, Tasawar

    2013-01-01

    This paper investigates the steady hydromagnetic three-dimensional boundary layer flow of Maxwell fluid over a bidirectional stretching surface. Both cases of prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations are made for the velocities and temperatures. Results are plotted and analyzed for PST and PHF cases. Convergence analysis is presented for the velocities and temperatures. Comparison of PST and PHF cases is given and examined. PMID:23874523

  7. Thermodynamics of topological black holes in Brans-Dicke gravity with a power-law Maxwell field

    NASA Astrophysics Data System (ADS)

    Zangeneh, M. Kord; Dehghani, M. H.; Sheykhi, A.

    2015-11-01

    In this paper, we present a new class of higher-dimensional exact topological black hole solutions of the Brans-Dicke theory in the presence of a power-law Maxwell field as the matter source. For this aim, we introduce a conformal transformation which transforms the Einstein-dilaton-power-law Maxwell gravity Lagrangian to the Brans-Dicke-power-law Maxwell theory one. Then, by using this conformal transformation, we obtain the desired solutions. Next, we study the properties of the solutions and conditions under which we have black holes. Interestingly enough, we show that there is a cosmological horizon in the presence of a negative cosmological constant. Finally, we calculate the temperature and charge and then by calculating the Euclidean action, we obtain the mass, the entropy and the electromagnetic potential energy. We find that the entropy does not respect the area law, and also the conserved and thermodynamic quantities are invariant under conformal transformation. Using these thermodynamic and conserved quantities, we show that the first law of black hole thermodynamics is satisfied on the horizon.

  8. A Brownian dynamics study on ferrofluid colloidal dispersions using an iterative constraint method to satisfy Maxwell's equations

    NASA Astrophysics Data System (ADS)

    Dubina, Sean Hyun; Wedgewood, Lewis Edward

    2016-07-01

    Ferrofluids are often favored for their ability to be remotely positioned via external magnetic fields. The behavior of particles in ferromagnetic clusters under uniformly applied magnetic fields has been computationally simulated using the Brownian dynamics, Stokesian dynamics, and Monte Carlo methods. However, few methods have been established that effectively handle the basic principles of magnetic materials, namely, Maxwell's equations. An iterative constraint method was developed to satisfy Maxwell's equations when a uniform magnetic field is imposed on ferrofluids in a heterogeneous Brownian dynamics simulation that examines the impact of ferromagnetic clusters in a mesoscale particle collection. This was accomplished by allowing a particulate system in a simple shear flow to advance by a time step under a uniformly applied magnetic field, then adjusting the ferroparticles via an iterative constraint method applied over sub-volume length scales until Maxwell's equations were satisfied. The resultant ferrofluid model with constraints demonstrates that the magnetoviscosity contribution is not as substantial when compared to homogeneous simulations that assume the material's magnetism is a direct response to the external magnetic field. This was detected across varying intensities of particle-particle interaction, Brownian motion, and shear flow. Ferroparticle aggregation was still extensively present but less so than typically observed.

  9. Final Environmental Assessment for Temporary Aircraft Relocation to Maxwell Air Force Base 187th Fighter Wing Montgomery Regional Airport Montgomery, Alabama

    DTIC Science & Technology

    2012-06-01

    Maxwell AFB, 187 FW Final – June 2012 8-1 CHAPTER 8 LIST OF PREPARERS Robert Dogan, REM Project Manager National Guard Bureau/A7AM Years of...and draft FONSI 2. Distribution li st Sincere ly ~/()/ ROBERT L. DOGAN, GS-13, REM Plans and Requi rements Branch Environmental Assessment for...ROBERT L. DOGAN, GS-13, REM Plans and Requirements Branch Environmental Assessment for Temporary Aircraft Relocation to Maxwell AFB, 187 FW Final

  10. Statistical tests of simple earthquake cycle models

    NASA Astrophysics Data System (ADS)

    DeVries, Phoebe M. R.; Evans, Eileen L.

    2016-12-01

    A central goal of observing and modeling the earthquake cycle is to forecast when a particular fault may generate an earthquake: a fault late in its earthquake cycle may be more likely to generate an earthquake than a fault early in its earthquake cycle. Models that can explain geodetic observations throughout the entire earthquake cycle may be required to gain a more complete understanding of relevant physics and phenomenology. Previous efforts to develop unified earthquake models for strike-slip faults have largely focused on explaining both preseismic and postseismic geodetic observations available across a few faults in California, Turkey, and Tibet. An alternative approach leverages the global distribution of geodetic and geologic slip rate estimates on strike-slip faults worldwide. Here we use the Kolmogorov-Smirnov test for similarity of distributions to infer, in a statistically rigorous manner, viscoelastic earthquake cycle models that are inconsistent with 15 sets of observations across major strike-slip faults. We reject a large subset of two-layer models incorporating Burgers rheologies at a significance level of α = 0.05 (those with long-term Maxwell viscosities ηM < 4.0 × 1019 Pa s and ηM > 4.6 × 1020 Pa s) but cannot reject models on the basis of transient Kelvin viscosity ηK. Finally, we examine the implications of these results for the predicted earthquake cycle timing of the 15 faults considered and compare these predictions to the geologic and historical record.

  11. Response of marine sedimentation to upper Holocene climate variability in Maxwell Bay, King George Island, West Antarctic Peninsula

    NASA Astrophysics Data System (ADS)

    Wittenberg, Nina; Hass, Christian; Kuhn, Gerhard

    2013-04-01

    The Western Antarctic Peninsula experiences a temperature increase that is higher than in other parts of Antarctica. Within the last 50 years the tidewater glaciers in the tributary fjords of Maxwell Bay (King George Island) have retreated landwards with increasing speed. Meltwaters mobilize fine-grained sediments and transport those in plumes out of the coves into Maxwell Bay. Our hypothesis is that meltwater sediments characterize warmer climate periods of the Holocene. Marine sediment cores recovered along a profile of the eastern slope of Maxwell Bay were studied. The cores were taken in high-accumulation areas at the entrances of Collins Harbor, Marian and Potter coves. We measured the grain-size distribution in 1-cm steps in each core with a Laser diffraction particle analyzer (range 0.04-2500 µm) in order to resolve shifts in grain size compositions in very high resolution. We undertook different approaches for reliable age determination of the sediments. Since marine biogenic carbonate suitable for radiocarbon age determination is sparse, radiocarbon dating of the extracted humic acid fraction of the bulk sediment was included. Unfortunately, these age determinations turned out to be not reliable, likely because they are overprinted by an unknown older radiocarbon source. Preliminary results suggest that the cores cover approximately the last 2000 years. The magnetic susceptibility (MS) parameter fluctuates throughout the cores. It is negatively correlated to the amount of total organic carbon (TOC) and biogenic opal, suggesting dilution of the MS signal through higher input of organic material. Together with the bathymetry data, sub-bottom profiles reveal information on the interior of the topography and the geometry of the deposited sediments. The profiles obtained in Potter Cove show almost no sediment penetration suggesting either a very thin sediment cover and/or highly reworked unsorted sediments. The sub-bottom profiles from Maxwell Bay penetrate

  12. Maxwell, Hertz and Marconi, using the history of science and technology in science education

    NASA Astrophysics Data System (ADS)

    Zito, Fredrick Anthony

    This dissertation examines the possibility of using a Kuhnian framework to enhance the use of history in the teaching of science. The Kuhnian framework of "revolutionary" and "normal" science, it is noted, provides a simplifying yet explanatory framework for students of science, at the same time making it possible to show the daily life of scientists. Rather than focus only on heroes of science, the work examines the important work of the "normal" scientist and their interplay with "revolutionary" scientists. It is argued that seeing the daily life of the scientist within this framework can show students of science the profound impact of the seemingly simple contributions of the work of scientists. In addition, it is noted that viewing the history of science as shifting paradigms and scientific revolutions will not only enhance students' scientific literacy, but possibly enhance their willingness to pursue science education. A review of the theoretical literature surrounding Kuhn, his followers and his critics, suggest the framework is still salient among educators. A review of the empirical literature and some educational practices suggests that educators see this approach to be effective, especially when the framework and case materials are carefully crafted. The empirical literature also suggests that there is a gap between the prescribed standards (national and state) for teaching the history of science, and actual classroom practice. The Kuhnian framework shows promise for bridging this gap. The dissertation then uses a case history of the discovery of electromagnetic radiation by Faraday, Maxwell, and Hertz et al., culminating in the development wireless telegraphy by Marconi, making possible radio, television, radar, and other contemporary technologies. The dissertation concludes by noting that the use of history as an arena for understanding science, in some way resembles the concept of "reflective thinking", which is often utilized as a framework for

  13. Strichartz Estimates and Moment Bounds for the Relativistic Vlasov-Maxwell System

    NASA Astrophysics Data System (ADS)

    Luk, Jonathan; Strain, Robert M.

    2016-01-01

    We consider the relativistic Vlasov-Maxwell system with data of unrestricted size and without compact support in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, Glassey-Schaeffer proved (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:331-354, 1998; Arch Ration Mech Anal. 141:355-374, 1998) that for regular initial data with compact momentum support this system has unique global in time classical solutions. In this work we do not assume compact momentum support for the initial data and instead require only that the data have polynomial decay in momentum space. In the two-dimensional and the two-and-a-half-dimensional cases, we prove the global existence, uniqueness and regularity for solutions arising from this class of initial data. To this end we use Strichartz estimates and prove that suitable moments of the solution remain bounded. Moreover, we obtain a slight improvement of the temporal growth of the {L^∞_x} norms of the electromagnetic fields compared to Glassey and Schaeffer (Commun Math Phys 185:257-284, 1997; Arch Ration Mech Anal 141:355-374, 1998). In the three-dimensional case, we apply Strichartz estimates and moment bounds to show that a regular solution can be extended as long as {{|p_0^{θ} f |_{LqxL^1p}}} remains bounded for {θ > 2/q}, {2 < q ≤q ∞}. This improves previous results of Pallard (Indiana Univ Math J 54(5):1395-1409, 2005; Commun Math Sci 13(2):347-354, 2015).

  14. Thermodynamics of Taub-NUT/bolt black holes in Einstein-Maxwell gravity

    SciTech Connect

    Dehghani, M.H.; Khodam-Mohammadi, A.

    2006-06-15

    First, we construct the Taub-NUT/bolt solutions of (2k+2)-dimensional Einstein-Maxwell gravity, when all the factor spaces of 2k-dimensional base space B have positive curvature. These solutions depend on two extra parameters, other than the mass and the NUT charge. These are electric charge q and electric potential at infinity V. We investigate the existence of Taub-NUT solutions and find that in addition to the two conditions of uncharged NUT solutions, there exist two extra conditions. These two extra conditions come from the regularity of vector potential at r=N and the fact that the horizon at r=N should be the outer horizon of the NUT charged black hole. We find that the NUT solutions in 2k+2 dimensions have no curvature singularity at r=N, when the 2k-dimensional base space is chosen to be CP{sup 2k}. For bolt solutions, there exists an upper limit for the NUT parameter which decreases as the potential parameter increases. Second, we study the thermodynamics of these spacetimes. We compute temperature, entropy, charge, electric potential, action and mass of the black hole solutions, and find that these quantities satisfy the first law of thermodynamics. We perform a stability analysis by computing the heat capacity, and show that the NUT solutions are not thermally stable for even k's, while there exists a stable phase for odd k's, which becomes increasingly narrow with increasing dimensionality and wide with increasing V. We also study the phase behavior of the 4 and 6 dimensional bolt solutions in canonical ensemble and find that these solutions have a stable phase, which becomes smaller as V increases.

  15. Mathematical and statistical analysis

    NASA Technical Reports Server (NTRS)

    Houston, A. Glen

    1988-01-01

    The goal of the mathematical and statistical analysis component of RICIS is to research, develop, and evaluate mathematical and statistical techniques for aerospace technology applications. Specific research areas of interest include modeling, simulation, experiment design, reliability assessment, and numerical analysis.

  16. Uterine Cancer Statistics

    MedlinePlus

    ... Research AMIGAS Fighting Cervical Cancer Worldwide Stay Informed Statistics for Other Kinds of Cancer Breast Cervical Colorectal ( ... Skin Vaginal and Vulvar Cancer Home Uterine Cancer Statistics Language: English Español (Spanish) Recommend on Facebook Tweet ...

  17. Experiment in Elementary Statistics

    ERIC Educational Resources Information Center

    Fernando, P. C. B.

    1976-01-01

    Presents an undergraduate laboratory exercise in elementary statistics in which students verify empirically the various aspects of the Gaussian distribution. Sampling techniques and other commonly used statistical procedures are introduced. (CP)

  18. Ethics in Statistics

    ERIC Educational Resources Information Center

    Lenard, Christopher; McCarthy, Sally; Mills, Terence

    2014-01-01

    There are many different aspects of statistics. Statistics involves mathematics, computing, and applications to almost every field of endeavour. Each aspect provides an opportunity to spark someone's interest in the subject. In this paper we discuss some ethical aspects of statistics, and describe how an introduction to ethics has been…

  19. Teaching Statistics Using SAS.

    ERIC Educational Resources Information Center

    Mandeville, Garrett K.

    The Statistical Analysis System (SAS) is presented as the single most appropriate statistical package to use as an aid in teaching statistics. A brief review of literature in which SAS is compared to SPSS, BMDP, and other packages is followed by six examples which demonstrate features unique to SAS which have pedagogical utility. Of particular…

  20. Minnesota Health Statistics 1988.

    ERIC Educational Resources Information Center

    Minnesota State Dept. of Health, St. Paul.

    This document comprises the 1988 annual statistical report of the Minnesota Center for Health Statistics. After introductory technical notes on changes in format, sources of data, and geographic allocation of vital events, an overview is provided of vital health statistics in all areas. Thereafter, separate sections of the report provide tables…

  1. Statistical analysis of cascaded PLC-based PMD compensator

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Wang, Lei; Wu, Xingkun

    2005-01-01

    The planar lightwave circuit (PLC) on silicon substrate offers a promising on-chip integrated solution to polarization-mode dispersion (PMD) compensation for long haul high speed communications. A novel cascaded PLC based PMD compensator is proposed in this paper and a detailed statistical analysis of PMD generated by cascaded PLC circuits is presented. Using Gisin and Pellaux's approach the distributions of first-order PMD produced by various multiple-stage PLC circuits were obtained by Monte Carlo simulation with respect to the phase shift introduced by heating elements in the circuits. The generated PMD was compared with a standard Maxwell distribution and that of a 12-stage nonlinear crystal based PMD compensator. It was found that a 3-stage cascaded PLC circuit yields a performance close to that of the crystal-based PMD compensator, while with a significant reduction in packaged size and enhancement in stability.

  2. Statistical mechanics of simple fluids - Beyond van der Waals

    NASA Astrophysics Data System (ADS)

    Lebowitz, J. L.; Waisman, E. M.

    1980-03-01

    Consideration is given to recent developments in the theory of dense fluids, based on a model fluid of hard spheres. The fluid is treated as consisting of electrically neutral particles interacting through pair potentials dependent only on the distance between their centers, a macroscopic system which can be described by classical statistical mechanics. The van der Waals equation of state and the Maxwell amendment to it for temperatures less than the critical temperature are reviewed, and subsequent rigorous derivations of the amended equation are presented. A relatively simple scheme for approximating a dense, single-component simple classical fluid whose atoms interact via the Lennard-Jones potential, based on the hard sphere model and employing computer calculations is then outlined. It is noted that the approach can be easily generalized to treat quantitatively mixtures of simple fluids, and nonuniform fluids qualitatively, and that there remains much to be done to understand why the schemes presented work as well as they do.

  3. Statistical Methods for Astronomy

    NASA Astrophysics Data System (ADS)

    Feigelson, Eric D.; Babu, G. Jogesh

    Statistical methodology, with deep roots in probability theory, providesquantitative procedures for extracting scientific knowledge from astronomical dataand for testing astrophysical theory. In recent decades, statistics has enormouslyincreased in scope and sophistication. After a historical perspective, this reviewoutlines concepts of mathematical statistics, elements of probability theory,hypothesis tests, and point estimation. Least squares, maximum likelihood, andBayesian approaches to statistical inference are outlined. Resampling methods,particularly the bootstrap, provide valuable procedures when distributionsfunctions of statistics are not known. Several approaches to model selection andgoodness of fit are considered.

  4. Aftershock Energy Distribution by Statistical Mechanics Approach

    NASA Astrophysics Data System (ADS)

    Daminelli, R.; Marcellini, A.

    2015-12-01

    The aim of our work is to research the most probable distribution of the energy of aftershocks. We started by applying one of the fundamental principles of statistical mechanics that, in case of aftershock sequences, it could be expressed as: the greater the number of different ways in which the energy of aftershocks can be arranged among the energy cells in phase space the more probable the distribution. We assume that each cell in phase space has the same possibility to be occupied, and that more than one cell in the phase space can have the same energy. Seeing that seismic energy is proportional to products of different parameters, a number of different combinations of parameters can produce different energies (e.g., different combination of stress drop and fault area can release the same seismic energy). Let us assume that there are gi cells in the aftershock phase space characterised by the same energy released ɛi. Therefore we can assume that the Maxwell-Boltzmann statistics can be applied to aftershock sequences with the proviso that the judgment on the validity of this hypothesis is the agreement with the data. The aftershock energy distribution can therefore be written as follow: n(ɛ)=Ag(ɛ)exp(-βɛ)where n(ɛ) is the number of aftershocks with energy, ɛ, A and β are constants. Considering the above hypothesis, we can assume g(ɛ) is proportional to ɛ. We selected and analysed different aftershock sequences (data extracted from Earthquake Catalogs of SCEC, of INGV-CNT and other institutions) with a minimum magnitude retained ML=2 (in some cases ML=2.6) and a time window of 35 days. The results of our model are in agreement with the data, except in the very low energy band, where our model resulted in a moderate overestimation.

  5. A 3D High-Order Unstructured Finite-Volume Algorithm for Solving Maxwell's Equations

    NASA Technical Reports Server (NTRS)

    Liu, Yen; Kwak, Dochan (Technical Monitor)

    1995-01-01

    A three-dimensional finite-volume algorithm based on arbitrary basis functions for time-dependent problems on general unstructured grids is developed. The method is applied to the time-domain Maxwell equations. Discrete unknowns are volume integrals or cell averages of the electric and magnetic field variables. Spatial terms are converted to surface integrals using the Gauss curl theorem. Polynomial basis functions are introduced in constructing local representations of the fields and evaluating the volume and surface integrals. Electric and magnetic fields are approximated by linear combinations of these basis functions. Unlike other unstructured formulations used in Computational Fluid Dynamics, the new formulation actually does not reconstruct the field variables at each time step. Instead, the spatial terms are calculated in terms of unknowns by precomputing weights at the beginning of the computation as functions of cell geometry and basis functions to retain efficiency. Since no assumption is made for cell geometry, this new formulation is suitable for arbitrarily defined grids, either smooth or unsmooth. However, to facilitate the volume and surface integrations, arbitrary polyhedral cells with polygonal faces are used in constructing grids. Both centered and upwind schemes are formulated. It is shown that conventional schemes (second order in Cartesian grids) are equivalent to the new schemes using first degree polynomials as the basis functions and the midpoint quadrature for the integrations. In the new formulation, higher orders of accuracy are achieved by using higher degree polynomial basis functions. Furthermore, all the surface and volume integrations are carried out exactly. Several model electromagnetic scattering problems are calculated and compared with analytical solutions. Examples are given for cases based on 0th to 3rd degree polynomial basis functions. In all calculations, a centered scheme is applied in the interior, while an upwind

  6. Maxwell-Wagner relaxation in common minerals and a desert soil at low water contents

    NASA Astrophysics Data System (ADS)

    Arcone, Steven A.; Boitnott, Ginger E.

    2012-06-01

    Penetration of 100- to 1000-MHz ground-penetrating radar (GPR) signals is virtually non-existent in arid and desert soils despite their low water content and moderate conductivity, the latter of which cannot explain the loss. Under the hypothesis that strong dielectric relaxation supplements DC conductivity to cause high intrinsic attenuation rates, we compared the complex permittivity of a desert soil sample with that of controlled samples of quartz, feldspars, calcite, coarse and crystallite gypsum, kaolinite and montmorillonite. The soil had 80% quartz, 10% feldspars and 10% gypsum by weight, with the latter composed of crystallites and crustations. All samples had 4-7% volumetric water content. We measured permittivity most accurately from 1.6 MHz to 4 GHz with Fourier Transform time domain reflectometry, and used grain sizes less than 53 μm. All samples show low-frequency dispersion with the soil, gypsum crystallites and montmorillonite having the strongest below 100 MHz, the highest attenuation rates, and conductivity values unable to account for these rates. The soil rate exceeded 100 dB m- 1 by 1 GHz. Through modeling we find that a broadened relaxation centered from 2 to 16 MHz sufficiently supplements losses caused by conductivity and free water relaxation to account for loss rates in all our samples, and accounts for low-frequency dispersion below 1 GHz. We interpret the relaxation to be of the Maxwell-Wagner (MW) type because of the 2- to 16-MHz values, relaxation broadening, the lack of salt, clay and magnetic minerals, and insufficient surface area to support adsorbed water. The likely MW dipolar soil inclusions within the predominantly quartz matrix were gypsum particles coated with water containing ions dissolved from the gypsum, and the conducting water layers themselves. The inclusions for the monomineralic soils were likely ionized partially or completely water-filled interstices, and partially filled galleries for the montmorillonite. The low

  7. Exact well behaved solutions of Einstein-Maxwell equations for relativistic charged superdense star models

    NASA Astrophysics Data System (ADS)

    Maurya, S. K.; Gupta, Y. K.

    2012-08-01

    We present a new class of static spherically symmetric exact solutions of the Einstein-Maxwell system of equations by considering a specific choice of electric intensity which involves a parameter K. The resulting solutions represent charged fluid spheres joining smoothly with the Reissner-Nordstrom metric at the pressure free interface. The solutions so obtained are utilised to construct the models for super-dense star, like neutron stars, strange quark stars and pulsars by taking the surface density as 2×1014 g/cm3. It is observed that the models are regular and well behaved for the restricted value of the parameter K (0.9155≤ K≤0.9485). Over all the model of maximum mass has radius a=10.5834 km and mass equivalent to 1.0111 M Θ. The pulsar character of the super-dense stars so obtained has been tested with the help of moment of inertia. As a consequence the super-dense star models are found capable of representing pulsars with their mass lying in the interval 0.2038 M Θ to 1.0111 M Θ with the radius spanning from 6.6819 km to 10.5834 km. The analysis of the models reveals the possibility of only Vela pulsars i.e. (i) Star model possessing mass 0.9324 M Θ, radius 10.3728 km, the red-shift at centre Z 0=0.1871 and at surface Z a =0.1093 and moment of inertia I=0.6412×1045 g cm2 for K=0.9155 and Ca 2=0.2727. (ii) An another star model possess, mass 0.8283 M Θ, radius 10.0910 km, the red-shift at centre Z 0=0.1658 and at surface Z a =0.0980 and moment of inertia I=0.5213×1045 g cm2 for K=0.9485 and Ca 2=0.2406.

  8. Saturation process induced by vortex-merging in numerical Vlasov-Maxwell experiments of stimulated Raman backscattering

    SciTech Connect

    Albrecht-Marc, M.; Ghizzo, A.; Johnston, T. W.; Reveille, T.; Del Sarto, D.; Bertrand, P.

    2007-07-15

    The influence of low-frequency nonlinear Bernstein-Greene-Kruskal (BGK)-type waves induced by trapped electrons in backward stimulated Raman scattering is investigated in optical mixing. Semi-Lagrangian Vlasov-Maxwell simulations show two nonlinear behaviors. First, there is a Morales-O'Neil plasma wave frequency downshift retuned by a small wavenumber shift which maintains the Stimulated Raman Scattering (SRS) resonance. The saturation of Raman backscattering begins with phase space vortex merging followed by a transition to lower wavenumbers following the (nonlinear) dispersion relation, resembling weak turbulence.

  9. A Non-Dissipative Staggered Fourth-Order Accurate Explicit Finite Difference Scheme for the Time-Domain Maxwell's Equations

    NASA Technical Reports Server (NTRS)

    Yefet, Amir; Petropoulos, Peter G.

    1999-01-01

    We consider a divergence-free non-dissipative fourth-order explicit staggered finite difference scheme for the hyperbolic Maxwell's equations. Special one-sided difference operators are derived in order to implement the scheme near metal boundaries and dielectric interfaces. Numerical results show the scheme is long-time stable, and is fourth-order convergent over complex domains that include dielectric interfaces and perfectly conducting surfaces. We also examine the scheme's behavior near metal surfaces that are not aligned with the grid axes, and compare its accuracy to that obtained by the Yee scheme.

  10. Stability of thin-shell wormholes supported by normal matter in Einstein-Maxwell-Gauss-Bonnet gravity

    SciTech Connect

    Mazharimousavi, S. Habib; Halilsoy, M.; Amirabi, Z.

    2010-05-15

    Recently in [Phys. Rev. D 76, 087502 (2007) and Phys. Rev. D 77, 089903 (2008)] a thin-shell wormhole has been introduced in five-dimensional Einstein-Maxwell-Gauss-Bonnet gravity which was supported by normal matter. We wish to consider this solution and investigate its stability. Our analysis shows that for the Gauss-Bonnet parameter {alpha}<0, stability regions form for a narrow band of finely tuned mass and charge. For the case {alpha}>0, we iterate once more that no stable, normal matter thin-shell wormhole exists.

  11. Direct time integration of Maxwell's equations in two-dimensional dielectric waveguides for propagation and scattering of femtosecond electromagnetic solitons

    NASA Technical Reports Server (NTRS)

    Joseph, Rose M.; Goorjian, Peter M.; Taflove, Allen

    1993-01-01

    We present what are to our knowledge first-time calculations from vector nonlinear Maxwell's equations of femtosecond soliton propagation and scattering, including carrier waves, in two-dimensional dielectric waveguides. The time integration efficiently implements linear and nonlinear convolutions for the electric polarization, and the nonlinear convolution accounts for two quantum effects, the Kerr and Raman interactions. By retaining the optical carrier, the new method solves for fundamental quantities - optical electric and magnetic fields in space and time - rather than a nonphysical envelope function. It has the potential to provide an unprecedented two- and three-dimensional modeling capability for millimeter-scale integrated-optical circuits with submicrometer engineered inhomogeneities.

  12. Optimized Schwarz algorithms for solving time-harmonic Maxwell's equations discretized by a hybridizable discontinuous Galerkin method

    NASA Astrophysics Data System (ADS)

    He, Yu-Xuan; Li, Liang; Lanteri, Stéphane; Huang, Ting-Zhu

    2016-03-01

    This work is concerned with the development of numerical methods for the simulation of time-harmonic electromagnetic wave propagation problems. A hybridizable discontinuous Galerkin (HDG) method is adopted for the discretization of the two-dimensional time-harmonic Maxwell's equations on a triangular mesh. A distinguishing feature of the present work is that this discretization method is employed at the subdomain level in the framework of a Schwarz-type domain decomposition algorithm (DDM). We show that HDG method naturally couples with a Schwarz method relying on optimized transmission conditions. The presented numerical results show the effectiveness of the optimized DDM-HDG method.

  13. Novel concepts for the systematic statistical analysis of phase transitions in finite systems

    NASA Astrophysics Data System (ADS)

    Bachmann, M.

    2014-03-01

    We review recent developments in the conceptual approach to a consistent systematic understanding of cooperative thermodynamic activity. The microcanonical statistical analysis is a powerful tool that is particularly useful for the investigation of analogs of phase transitions in finite systems, but it applies also in the extrapolation toward the thermodynamic limit. Whereas Maxwell construction in the coexistence region in the inverse caloric temperature space is a reasonable method for individual first-order-like transitions that are well-separated from other energetic regions of thermal activity, microcanonical inflection-point analysis is a systematic method that enables both the identification and classification of transitions of first and higher orders.

  14. Heroin: Statistics and Trends

    MedlinePlus

    ... Naloxone Pain Prevention Treatment Trends & Statistics Women and Drugs Publications Funding Funding Opportunities Clinical Research Post-Award Concerns General Information Grant & Contract Application ...

  15. Statistical distribution sampling

    NASA Technical Reports Server (NTRS)

    Johnson, E. S.

    1975-01-01

    Determining the distribution of statistics by sampling was investigated. Characteristic functions, the quadratic regression problem, and the differential equations for the characteristic functions are analyzed.

  16. Explorations in Statistics: Power

    ERIC Educational Resources Information Center

    Curran-Everett, Douglas

    2010-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This fifth installment of "Explorations in Statistics" revisits power, a concept fundamental to the test of a null hypothesis. Power is the probability that we reject the null hypothesis when it is false. Four…

  17. Teaching Statistics without Sadistics.

    ERIC Educational Resources Information Center

    Forte, James A.

    1995-01-01

    Five steps designed to take anxiety out of statistics for social work students are outlined. First, statistics anxiety is identified as an educational problem. Second, instructional objectives and procedures to achieve them are presented and methods and tools for evaluating the course are explored. Strategies for, and obstacles to, making…

  18. STATSIM: Exercises in Statistics.

    ERIC Educational Resources Information Center

    Thomas, David B.; And Others

    A computer-based learning simulation was developed at Florida State University which allows for high interactive responding via a time-sharing terminal for the purpose of demonstrating descriptive and inferential statistics. The statistical simulation (STATSIM) is comprised of four modules--chi square, t, z, and F distribution--and elucidates the…

  19. Understanding Undergraduate Statistical Anxiety

    ERIC Educational Resources Information Center

    McKim, Courtney

    2014-01-01

    The purpose of this study was to understand undergraduate students' views of statistics. Results reveal that students with less anxiety have a higher interest in statistics and also believe in their ability to perform well in the course. Also students who have a more positive attitude about the class tend to have a higher belief in their…

  20. Water Quality Statistics

    ERIC Educational Resources Information Center

    Hodgson, Ted; Andersen, Lyle; Robison-Cox, Jim; Jones, Clain

    2004-01-01

    Water quality experiments, especially the use of macroinvertebrates as indicators of water quality, offer an ideal context for connecting statistics and science. In the STAR program for secondary students and teachers, water quality experiments were also used as a context for teaching statistics. In this article, we trace one activity that uses…

  1. Towards Statistically Undetectable Steganography

    DTIC Science & Technology

    2011-06-30

    Statistically Undciectable Steganography 5a. CONTRACT NUMBER FA9550-08-1-0084 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Prof. Jessica...approved for public release: distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT Fundamental asymptotic laws for imperfect steganography ...formats. 15. SUBJECT TERMS Steganography . covert communication, statistical detectability. asymptotic performance, secure pay load, minimum

  2. Explorations in Statistics: Regression

    ERIC Educational Resources Information Center

    Curran-Everett, Douglas

    2011-01-01

    Learning about statistics is a lot like learning about science: the learning is more meaningful if you can actively explore. This seventh installment of "Explorations in Statistics" explores regression, a technique that estimates the nature of the relationship between two things for which we may only surmise a mechanistic or predictive…

  3. Option Y, Statistics.

    ERIC Educational Resources Information Center

    Singer, Arlene

    This guide outlines a one semester Option Y course, which has seven learner objectives. The course is designed to provide students with an introduction to the concerns and methods of statistics, and to equip them to deal with the many statistical matters of importance to society. Topics covered include graphs and charts, collection and…

  4. On Statistical Testing.

    ERIC Educational Resources Information Center

    Huberty, Carl J.

    An approach to statistical testing, which combines Neyman-Pearson hypothesis testing and Fisher significance testing, is recommended. The use of P-values in this approach is discussed in some detail. The author also discusses some problems which are often found in introductory statistics textbooks. The problems involve the definitions of…

  5. Statistics and Measurements

    PubMed Central

    Croarkin, M. Carroll

    2001-01-01

    For more than 50 years, the Statistical Engineering Division (SED) has been instrumental in the success of a broad spectrum of metrology projects at NBS/NIST. This paper highlights fundamental contributions of NBS/NIST statisticians to statistics and to measurement science and technology. Published methods developed by SED staff, especially during the early years, endure as cornerstones of statistics not only in metrology and standards applications, but as data-analytic resources used across all disciplines. The history of statistics at NBS/NIST began with the formation of what is now the SED. Examples from the first five decades of the SED illustrate the critical role of the division in the successful resolution of a few of the highly visible, and sometimes controversial, statistical studies of national importance. A review of the history of major early publications of the division on statistical methods, design of experiments, and error analysis and uncertainty is followed by a survey of several thematic areas. The accompanying examples illustrate the importance of SED in the history of statistics, measurements and standards: calibration and measurement assurance, interlaboratory tests, development of measurement methods, Standard Reference Materials, statistical computing, and dissemination of measurement technology. A brief look forward sketches the expanding opportunity and demand for SED statisticians created by current trends in research and development at NIST. PMID:27500023

  6. [Statistics quantum satis].

    PubMed

    Pestana, Dinis

    2013-01-01

    Statistics is a privileged tool in building knowledge from information, since the purpose is to extract from a sample limited information conclusions to the whole population. The pervasive use of statistical software (that always provides an answer, the question being adequate or not), and the absence of statistics to confer a scientific flavour to so much bad science, has had a pernicious effect on some disbelief on statistical research. Would Lord Rutherford be alive today, it is almost certain that he would not condemn the use of statistics in research, as he did in the dawn of the 20th century. But he would indeed urge everyone to use statistics quantum satis, since to use bad data, too many data, and statistics to enquire on irrelevant questions, is a source of bad science, namely because with too many data we can establish statistical significance of irrelevant results. This is an important point that addicts of evidence based medicine should be aware of, since the meta analysis of two many data will inevitably establish senseless results.

  7. Reform in Statistical Education

    ERIC Educational Resources Information Center

    Huck, Schuyler W.

    2007-01-01

    Two questions are considered in this article: (a) What should professionals in school psychology do in an effort to stay current with developments in applied statistics? (b) What should they do with their existing knowledge to move from surface understanding of statistics to deep understanding? Written for school psychologists who have completed…

  8. Deconstructing Statistical Analysis

    ERIC Educational Resources Information Center

    Snell, Joel

    2014-01-01

    Using a very complex statistical analysis and research method for the sake of enhancing the prestige of an article or making a new product or service legitimate needs to be monitored and questioned for accuracy. 1) The more complicated the statistical analysis, and research the fewer the number of learned readers can understand it. This adds a…

  9. Statistics 101 for Radiologists.

    PubMed

    Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

    2015-10-01

    Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced.

  10. Applied Statistics with SPSS

    ERIC Educational Resources Information Center

    Huizingh, Eelko K. R. E.

    2007-01-01

    Accessibly written and easy to use, "Applied Statistics Using SPSS" is an all-in-one self-study guide to SPSS and do-it-yourself guide to statistics. What is unique about Eelko Huizingh's approach is that this book is based around the needs of undergraduate students embarking on their own research project, and its self-help style is designed to…

  11. Overhead Image Statistics

    SciTech Connect

    Vijayaraj, Veeraraghavan; Cheriyadat, Anil M; Bhaduri, Budhendra L; Vatsavai, Raju; Bright, Eddie A

    2008-01-01

    Statistical properties of high-resolution overhead images representing different land use categories are analyzed using various local and global statistical image properties based on the shape of the power spectrum, image gradient distributions, edge co-occurrence, and inter-scale wavelet coefficient distributions. The analysis was performed on a database of high-resolution (1 meter) overhead images representing a multitude of different downtown, suburban, commercial, agricultural and wooded exemplars. Various statistical properties relating to these image categories and their relationship are discussed. The categorical variations in power spectrum contour shapes, the unique gradient distribution characteristics of wooded categories, the similarity in edge co-occurrence statistics for overhead and natural images, and the unique edge co-occurrence statistics of downtown categories are presented in this work. Though previous work on natural image statistics has showed some of the unique characteristics for different categories, the relationships for overhead images are not well understood. The statistical properties of natural images were used in previous studies to develop prior image models, to predict and index objects in a scene and to improve computer vision models. The results from our research findings can be used to augment and adapt computer vision algorithms that rely on prior image statistics to process overhead images, calibrate the performance of overhead image analysis algorithms, and derive features for better discrimination of overhead image categories.

  12. Numerical solutions of the macroscopic Maxwell equations for scattering by non-spherical particles: A tutorial review

    NASA Astrophysics Data System (ADS)

    Kahnert, Michael

    2016-07-01

    Numerical solution methods for electromagnetic scattering by non-spherical particles comprise a variety of different techniques, which can be traced back to different assumptions and solution strategies applied to the macroscopic Maxwell equations. One can distinguish between time- and frequency-domain methods; further, one can divide numerical techniques into finite-difference methods (which are based on approximating the differential operators), separation-of-variables methods (which are based on expanding the solution in a complete set of functions, thus approximating the fields), and volume integral-equation methods (which are usually solved by discretisation of the target volume and invoking the long-wave approximation in each volume cell). While existing reviews of the topic often tend to have a target audience of program developers and expert users, this tutorial review is intended to accommodate the needs of practitioners as well as novices to the field. The required conciseness is achieved by limiting the presentation to a selection of illustrative methods, and by omitting many technical details that are not essential at a first exposure to the subject. On the other hand, the theoretical basis of numerical methods is explained with little compromises in mathematical rigour; the rationale is that a good grasp of numerical light scattering methods is best achieved by understanding their foundation in Maxwell's theory.

  13. A scientific report on heat transfer analysis in mixed convection flow of Maxwell fluid over an oscillating vertical plate

    NASA Astrophysics Data System (ADS)

    Khan, Ilyas; Shah, Nehad Ali; Dennis, L. C. C.

    2017-03-01

    This scientific report investigates the heat transfer analysis in mixed convection flow of Maxwell fluid over an oscillating vertical plate with constant wall temperature. The problem is modelled in terms of coupled partial differential equations with initial and boundary conditions. Some suitable non-dimensional variables are introduced in order to transform the governing problem into dimensionless form. The resulting problem is solved via Laplace transform method and exact solutions for velocity, shear stress and temperature are obtained. These solutions are greatly influenced with the variation of embedded parameters which include the Prandtl number and Grashof number for various times. In the absence of free convection, the corresponding solutions representing the mechanical part of velocity reduced to the well known solutions in the literature. The total velocity is presented as a sum of both cosine and sine velocities. The unsteady velocity in each case is arranged in the form of transient and post transient parts. It is found that the post transient parts are independent of time. The solutions corresponding to Newtonian fluids are recovered as a special case and comparison between Newtonian fluid and Maxwell fluid is shown graphically.

  14. A scientific report on heat transfer analysis in mixed convection flow of Maxwell fluid over an oscillating vertical plate

    PubMed Central

    Khan, Ilyas; Shah, Nehad Ali; Dennis, L. C. C.

    2017-01-01

    This scientific report investigates the heat transfer analysis in mixed convection flow of Maxwell fluid over an oscillating vertical plate with constant wall temperature. The problem is modelled in terms of coupled partial differential equations with initial and boundary conditions. Some suitable non-dimensional variables are introduced in order to transform the governing problem into dimensionless form. The resulting problem is solved via Laplace transform method and exact solutions for velocity, shear stress and temperature are obtained. These solutions are greatly influenced with the variation of embedded parameters which include the Prandtl number and Grashof number for various times. In the absence of free convection, the corresponding solutions representing the mechanical part of velocity reduced to the well known solutions in the literature. The total velocity is presented as a sum of both cosine and sine velocities. The unsteady velocity in each case is arranged in the form of transient and post transient parts. It is found that the post transient parts are independent of time. The solutions corresponding to Newtonian fluids are recovered as a special case and comparison between Newtonian fluid and Maxwell fluid is shown graphically. PMID:28294186

  15. Heat Generation/Absorption Effects in a Boundary Layer Stretched Flow of Maxwell Nanofluid: Analytic and Numeric Solutions.

    PubMed

    Awais, Muhammad; Hayat, Tasawar; Irum, Sania; Alsaedi, Ahmed

    2015-01-01

    Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM) has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion "Db" and thermophoresis effects "Dt" occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis.

  16. A New Theoretical Approach Based on the Maxwell Model to Obtain Rheological Properties of Solidifying Alloys and Its Validation

    NASA Astrophysics Data System (ADS)

    Matsushita, Akira; Takai, Ryosuke; Ezaki, Hideaki; Okane, Toshimitsu; Yoshida, Makoto

    2017-04-01

    This paper proposes a new method for obtaining the rheological properties of solidifying alloys in the brittle temperature range (BTR). In that range, alloys show not only rheological, but also brittle behavior. Conventional methods to obtain rheological properties require steady state stress with ductility. Therefore, rheological properties of BTR alloys are unobtainable, or are otherwise including the effects of microscopic damage. The method proposed in this paper uses the stress-strain relation derived from the Maxwell model assuming that strain hardening is negligible in solid-liquid coexistence states. By removing the plastic strain term, the creep strain rate in Norton's law is derived by the total strain rate and stress rate without the steady state stress condition. Consequently, the stress exponent n and material constant A of Norton's law can be obtained even for alloys in the BTR. We applied this method to both tensile process before crack initiation and stress relaxation process. According to the Maxwell model, couples of the properties ( n and A) obtained in both processes must be equal. Therefore, the difference can validate the obtained properties. From tensile and stress relaxation tests, we obtained the properties of solidifying Al-5 wt pct Mg alloy. We validated results by examining the difference. This report is the first to provide a method to obtain the rheological properties of BTR alloy without damage.

  17. A Fourier penalty method for solving the time-dependent Maxwell's equations in domains with curved boundaries

    NASA Astrophysics Data System (ADS)

    Galagusz, Ryan; Shirokoff, David; Nave, Jean-Christophe

    2016-02-01

    We present a high order, Fourier penalty method for the Maxwell's equations in the vicinity of perfect electric conductor boundary conditions. The approach relies on extending the smooth non-periodic domain of the equations to a periodic domain by removing the exact boundary conditions and introducing an analytic forcing term in the extended domain. The forcing, or penalty term is chosen to systematically enforce the boundary conditions to high order in the penalty parameter, which then allows for higher order numerical methods. We present an efficient numerical method for constructing the penalty term, and discretize the resulting equations using a Fourier spectral method. We demonstrate convergence orders of up to 3.5 for the one-dimensional Maxwell's equations, and show that the numerical method does not suffer from dispersion (or pollution) errors. We also illustrate the approach in two dimensions and demonstrate convergence orders of 2.5 for transverse magnetic modes and 1.5 for the transverse electric modes. We conclude the paper with numerous test cases in dimensions two and three including waves traveling in a bent waveguide, and scattering off of a windmill-like geometry.

  18. Heat Generation/Absorption Effects in a Boundary Layer Stretched Flow of Maxwell Nanofluid: Analytic and Numeric Solutions

    PubMed Central

    Awais, Muhammad; Hayat, Tasawar; Irum, Sania; Alsaedi, Ahmed

    2015-01-01

    Analysis has been done to investigate the heat generation/absorption effects in a steady flow of non-Newtonian nanofluid over a surface which is stretching linearly in its own plane. An upper convected Maxwell model (UCM) has been utilized as the non-Newtonian fluid model in view of the fact that it can predict relaxation time phenomenon which the Newtonian model cannot. Behavior of the relaxations phenomenon has been presented in terms of Deborah number. Transport phenomenon with convective cooling process has been analyzed. Brownian motion “Db” and thermophoresis effects “Dt” occur in the transport equations. The momentum, energy and nanoparticle concentration profiles are examined with respect to the involved rheological parameters namely the Deborah number, source/sink parameter, the Brownian motion parameters, thermophoresis parameter and Biot number. Both numerical and analytic solutions are presented and found in nice agreement. Comparison with the published data is also made to ensure the validity. Stream lines for Maxwell and Newtonian fluid models are presented in the analysis. PMID:26115101

  19. A spherically symmetric bound state of the coupled Maxwell-Dirac equations with self-interaction alone

    NASA Astrophysics Data System (ADS)

    Bradford, R. A. W.

    2015-10-01

    Stationary, static, spherically symmetric solutions of the Maxwell-Dirac system, treated as classical fields, have been found which are localised and normalisable. The solutions apply to any bound energy eigenvalue in the range 0 < E < m, where m is the bare mass in the Dirac equation. A point charge of any magnitude and either sign may be placed at the origin and the solutions remain well behaved and bound. However, no such central charge is necessary to result in a bound solution. As found previously by Radford, the magnetic flux density is equal to that of a monopole at the origin. However, no monopole is present, the magnetic flux being a result of the dipole moment distribution of the Dirac field. The Dirac field magnetic dipole moment is aligned with the magnetic flux density and so the resulting magnetic self-energy is negative. It is this which results in the states being bound (E < m). The case which omits any central point charge is therefore a self-sustaining bound state solution of the Maxwell-Dirac system which is localised, normalisable, and requires no arbitrarily added "external" features (i.e., it is a soliton). As far as the author is aware, this is the first time that such an exact solution with a positive energy eigenvalue has been reported. However, the solution is not unique since the energy eigenvalue is arbitrary within the range 0 < E < m. The stability of the solution has not been addressed.

  20. Comparison of a 3-D GPU-Assisted Maxwell Code and Ray Tracing for Reflectometry on ITER

    NASA Astrophysics Data System (ADS)

    Gady, Sarah; Kubota, Shigeyuki; Johnson, Irena

    2015-11-01

    Electromagnetic wave propagation and scattering in magnetized plasmas are important diagnostics for high temperature plasmas. 1-D and 2-D full-wave codes are standard tools for measurements of the electron density profile and fluctuations; however, ray tracing results have shown that beam propagation in tokamak plasmas is inherently a 3-D problem. The GPU-Assisted Maxwell Code utilizes the FDTD (Finite-Difference Time-Domain) method for solving the Maxwell equations with the cold plasma approximation in a 3-D geometry. Parallel processing with GPGPU (General-Purpose computing on Graphics Processing Units) is used to accelerate the computation. Previously, we reported on initial comparisons of the code results to 1-D numerical and analytical solutions, where the size of the computational grid was limited by the on-board memory of the GPU. In the current study, this limitation is overcome by using domain decomposition and an additional GPU. As a practical application, this code is used to study the current design of the ITER Low Field Side Reflectometer (LSFR) for the Equatorial Port Plug 11 (EPP11). A detailed examination of Gaussian beam propagation in the ITER edge plasma will be presented, as well as comparisons with ray tracing. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No.DE-AC02-09CH11466 and DE-FG02-99-ER54527.

  1. Statistical mechanics in the context of special relativity. II.

    PubMed

    Kaniadakis, G

    2005-09-01

    The special relativity laws emerge as one-parameter (light speed) generalizations of the corresponding laws of classical physics. These generalizations, imposed by the Lorentz transformations, affect both the definition of the various physical observables (e.g., momentum, energy, etc.), as well as the mathematical apparatus of the theory. Here, following the general lines of [Phys. Rev. E 66, 056125 (2002)], we show that the Lorentz transformations impose also a proper one-parameter generalization of the classical Boltzmann-Gibbs-Shannon entropy. The obtained relativistic entropy permits us to construct a coherent and self-consistent relativistic statistical theory, preserving the main features of the ordinary statistical theory, which is recovered in the classical limit. The predicted distribution function is a one-parameter continuous deformation of the classical Maxwell-Boltzmann distribution and has a simple analytic form, showing power law tails in accordance with the experimental evidence. Furthermore, this statistical mechanics can be obtained as the stationary case of a generalized kinetic theory governed by an evolution equation obeying the H theorem and reproducing the Boltzmann equation of the ordinary kinetics in the classical limit.

  2. Statistics at a glance.

    PubMed

    Ector, Hugo

    2010-12-01

    I still remember my first book on statistics: "Elementary statistics with applications in medicine and the biological sciences" by Frederick E. Croxton. For me, it has been the start of pursuing understanding statistics in daily life and in medical practice. It was the first volume in a long row of books. In his introduction, Croxton pretends that"nearly everyone involved in any aspect of medicine needs to have some knowledge of statistics". The reality is that for many clinicians, statistics are limited to a "P < 0.05 = ok". I do not blame my colleagues who omit the paragraph on statistical methods. They have never had the opportunity to learn concise and clear descriptions of the key features. I have experienced how some authors can describe difficult methods in a well understandable language. Others fail completely. As a teacher, I tell my students that life is impossible without a basic knowledge of statistics. This feeling has resulted in an annual seminar of 90 minutes. This tutorial is the summary of this seminar. It is a summary and a transcription of the best pages I have detected.

  3. Temperature-tuned Maxwell-Boltzmann neutron spectra for kT ranging from 30 up to 50 keV for nuclear astrophysics studies.

    PubMed

    Martín-Hernández, G; Mastinu, P F; Praena, J; Dzysiuk, N; Capote Noy, R; Pignatari, M

    2012-08-01

    The need of neutron capture cross section measurements for astrophysics motivates present work, where calculations to generate stellar neutron spectra at different temperatures are performed. The accelerator-based (7)Li(p,n)(7)Be reaction is used. Shaping the proton beam energy and the sample covering a specific solid angle, neutron activation for measuring stellar-averaged capture cross section can be done. High-quality Maxwell-Boltzmann neutron spectra are predicted. Assuming a general behavior of the neutron capture cross section a weighted fit of the spectrum to Maxwell-Boltzmann distributions is successfully introduced.

  4. Informal Statistics Help Desk

    NASA Technical Reports Server (NTRS)

    Young, M.; Koslovsky, M.; Schaefer, Caroline M.; Feiveson, A. H.

    2017-01-01

    Back by popular demand, the JSC Biostatistics Laboratory and LSAH statisticians are offering an opportunity to discuss your statistical challenges and needs. Take the opportunity to meet the individuals offering expert statistical support to the JSC community. Join us for an informal conversation about any questions you may have encountered with issues of experimental design, analysis, or data visualization. Get answers to common questions about sample size, repeated measures, statistical assumptions, missing data, multiple testing, time-to-event data, and when to trust the results of your analyses.

  5. Commentary: statistics for biomarkers.

    PubMed

    Lovell, David P

    2012-05-01

    This short commentary discusses Biomarkers' requirements for the reporting of statistical analyses in submitted papers. It is expected that submitters will follow the general instructions of the journal, the more detailed guidance given by the International Committee of Medical Journal Editors, the specific guidelines developed by the EQUATOR network, and those of various specialist groups. Biomarkers expects that the study design and subsequent statistical analyses are clearly reported and that the data reported can be made available for independent assessment. The journal recognizes that there is continuing debate about different approaches to statistical science. Biomarkers appreciates that the field continues to develop rapidly and encourages the use of new methodologies.

  6. LED champing: statistically blessed?

    PubMed

    Wang, Zhuo

    2015-06-10

    LED champing (smart mixing of individual LEDs to match the desired color and lumens) and color mixing strategies have been widely used to maintain the color consistency of light engines. Light engines with champed LEDs can easily achieve the color consistency of a couple MacAdam steps with widely distributed LEDs to begin with. From a statistical point of view, the distributions for the color coordinates and the flux after champing are studied. The related statistical parameters are derived, which facilitate process improvements such as Six Sigma and are instrumental to statistical quality control for mass productions.

  7. Playing at Statistical Mechanics

    ERIC Educational Resources Information Center

    Clark, Paul M.; And Others

    1974-01-01

    Discussed are the applications of counting techniques of a sorting game to distributions and concepts in statistical mechanics. Included are the following distributions: Fermi-Dirac, Bose-Einstein, and most probable. (RH)

  8. Hemophilia Data and Statistics

    MedlinePlus

    ... Hemophilia Women Healthcare Providers Partners Media Policy Makers Data & Statistics Language: English Español (Spanish) Recommend on Facebook ... at a very young age. Based on CDC data, the median age at diagnosis is 36 months ...

  9. Cooperative Learning in Statistics.

    ERIC Educational Resources Information Center

    Keeler, Carolyn M.; And Others

    1994-01-01

    Formal use of cooperative learning techniques proved effective in improving student performance and retention in a freshman level statistics course. Lectures interspersed with group activities proved effective in increasing conceptual understanding and overall class performance. (11 references) (Author)

  10. Statistics of the sagas

    NASA Astrophysics Data System (ADS)

    Richfield, Jon; bookfeller

    2016-07-01

    In reply to Ralph Kenna and Pádraig Mac Carron's feature article “Maths meets myths” in which they describe how they are using techniques from statistical physics to characterize the societies depicted in ancient Icelandic sagas.

  11. Elements of Statistics

    NASA Astrophysics Data System (ADS)

    Grégoire, G.

    2016-05-01

    This chapter is devoted to two objectives. The first one is to answer the request expressed by attendees of the first Astrostatistics School (Annecy, October 2013) to be provided with an elementary vademecum of statistics that would facilitate understanding of the given courses. In this spirit we recall very basic notions, that is definitions and properties that we think sufficient to benefit from courses given in the Astrostatistical School. Thus we give briefly definitions and elementary properties on random variables and vectors, distributions, estimation and tests, maximum likelihood methodology. We intend to present basic ideas in a hopefully comprehensible way. We do not try to give a rigorous presentation, and due to the place devoted to this chapter, can cover only a rather limited field of statistics. The second aim is to focus on some statistical tools that are useful in classification: basic introduction to Bayesian statistics, maximum likelihood methodology, Gaussian vectors and Gaussian mixture models.

  12. Plague Maps and Statistics

    MedlinePlus

    ... and Statistics Recommend on Facebook Tweet Share Compartir Plague in the United States Plague was first introduced ... per year in the United States: 1900-2012. Plague Worldwide Plague epidemics have occurred in Africa, Asia, ...

  13. Understanding Solar Flare Statistics

    NASA Astrophysics Data System (ADS)

    Wheatland, M. S.

    2005-12-01

    A review is presented of work aimed at understanding solar flare statistics, with emphasis on the well known flare power-law size distribution. Although avalanche models are perhaps the favoured model to describe flare statistics, their physical basis is unclear, and they are divorced from developing ideas in large-scale reconnection theory. An alternative model, aimed at reconciling large-scale reconnection models with solar flare statistics, is revisited. The solar flare waiting-time distribution has also attracted recent attention. Observed waiting-time distributions are described, together with what they might tell us about the flare phenomenon. Finally, a practical application of flare statistics to flare prediction is described in detail, including the results of a year of automated (web-based) predictions from the method.

  14. Titanic: A Statistical Exploration.

    ERIC Educational Resources Information Center

    Takis, Sandra L.

    1999-01-01

    Uses the available data about the Titanic's passengers to interest students in exploring categorical data and the chi-square distribution. Describes activities incorporated into a statistics class and gives additional resources for collecting information about the Titanic. (ASK)

  15. Purposeful Statistical Investigations

    ERIC Educational Resources Information Center

    Day, Lorraine

    2014-01-01

    Lorraine Day provides us with a great range of statistical investigations using various resources such as maths300 and TinkerPlots. Each of the investigations link mathematics to students' lives and provide engaging and meaningful contexts for mathematical inquiry.

  16. Boosted Statistical Mechanics

    NASA Astrophysics Data System (ADS)

    Testa, Massimo

    2015-08-01

    Starting with the basic principles of Relativistic Quantum Mechanics, we give a rigorous, but completely elementary proof of the relation between fundamental observables of a statistical system, when measured within two inertial reference frames, related by a Lorentz transformation.

  17. How Statistics "Excel" Online.

    ERIC Educational Resources Information Center

    Chao, Faith; Davis, James

    2000-01-01

    Discusses the use of Microsoft Excel software and provides examples of its use in an online statistics course at Golden Gate University in the areas of randomness and probability, sampling distributions, confidence intervals, and regression analysis. (LRW)

  18. A Maxwell-Schrödinger solver for quantum optical few-level systems

    NASA Astrophysics Data System (ADS)

    Fleischhaker, Robert; Evers, Jörg

    2011-03-01

    The msprop program presented in this work is capable of solving the Maxwell-Schrödinger equations for one or several laser fields propagating through a medium of quantum optical few-level systems in one spatial dimension and in time. In particular, it allows to numerically treat systems in which a laser field interacts with the medium with both its electric and magnetic component at the same time. The internal dynamics of the few-level system is modeled by a quantum optical master equation which includes coherent processes due to optical transitions driven by the laser fields as well as incoherent processes due to decay and dephasing. The propagation dynamics of the laser fields is treated in slowly varying envelope approximation resulting in a first order wave equation for each laser field envelope function. The program employs an Adams predictor formula second order in time to integrate the quantum optical master equation and a Lax-Wendroff scheme second order in space and time to evolve the wave equations for the fields. The source function in the Lax-Wendroff scheme is specifically adapted to allow taking into account the simultaneous coupling of a laser field to the polarization and the magnetization of the medium. To reduce execution time, a customized data structure is implemented and explained. In three examples the features of the program are demonstrated and the treatment of a system with a phase-dependent cross coupling of the electric and magnetic field component of a laser field is shown. Program summaryProgram title: msprop Catalogue identifier: AEHR_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHR_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 507 625 No. of bytes in distributed program, including test data, etc.: 10 698 552

  19. Cattaneo-Christov Heat Flux Model for MHD Three-Dimensional Flow of Maxwell Fluid over a Stretching Sheet.

    PubMed

    Rubab, Khansa; Mustafa, M

    2016-01-01

    This letter investigates the MHD three-dimensional flow of upper-convected Maxwell (UCM) fluid over a bi-directional stretching surface by considering the Cattaneo-Christov heat flux model. This model has tendency to capture the characteristics of thermal relaxation time. The governing partial differential equations even after employing the boundary layer approximations are non linear. Accurate analytic solutions for velocity and temperature distributions are computed through well-known homotopy analysis method (HAM). It is noticed that velocity decreases and temperature rises when stronger magnetic field strength is accounted. Penetration depth of temperature is a decreasing function of thermal relaxation time. The analysis for classical Fourier heat conduction law can be obtained as a special case of the present work. To our knowledge, the Cattaneo-Christov heat flux model law for three-dimensional viscoelastic flow problem is just introduced here.

  20. Comment on “Maxwell's equations and electromagnetic Lagrangian density in fractional form” [J. Math. Phys. 53, 033505 (2012)

    SciTech Connect

    Rabei, Eqab M.; Al-Jamel, A.; Widyan, H.; Baleanu, D.

    2014-03-15

    In a recent paper, Jaradat et al. [J. Math. Phys. 53, 033505 (2012)] have presented the fractional form of the electromagnetic Lagrangian density within the Riemann-Liouville fractional derivative. They claimed that the Agrawal procedure [O. P. Agrawal, J. Math. Anal. Appl. 272, 368 (2002)] is used to obtain Maxwell's equations in the fractional form, and the Hamilton's equations of motion together with the conserved quantities obtained from fractional Noether's theorem are reported. In this comment, we draw the attention that there are some serious steps of the procedure used in their work are not applicable even though their final results are correct. Their work should have been done based on a formulation as reported by Baleanu and Muslih [Phys. Scr. 72, 119 (2005)].