A New Observing Tool for the James Clerk Maxwell Telescope
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).
SCUBA A submillimetre camera operating on the James Clerk Maxwell Telescope
Holland, W S; Gear, W K; Jenness, T; Laidlaw, K; Lightfoot, J F; Robson, E I; Holland, Wayne S.; Cunningham, Colin R.; Gear, Walter K.; Jenness, Tim; Laidlaw, Ken; Lightfoot, John F.
1998-01-01
The Submillimetre Common-User Bolometer Array (SCUBA) is one of a new generation of cameras designed to operate in the submillimetre waveband. The instrument has a wide wavelength range covering all the atmospheric transmission windows between 300 and 2000 microns. In the heart of the instrument are two arrays of bolometers optimised for the short (350/450 microns) and long (750/850 microns) wavelength ends of the submillimetre spectrum. The two arrays can be used simultaneously, giving a unique dual-wavelength capability, and have a 2.3 arc-minute field of view on the sky. Background-limited performance is achieved by cooling the arrays to below 100 mK. SCUBA has now been in active service for over a year, and has already made substantial breakthroughs in many areas of astronomy. In this paper we present an overview of the performance of SCUBA during the commissioning phase on the James Clerk Maxwell Telescope (JCMT).
SCUBA-2: The 10000 pixel bolometer camera on the James Clerk Maxwell Telescope
Holland, W S; Chapin, E L; Chrysostomou, A; Davis, G R; Dempsey, J T; Duncan, W D; Fich, M; Friberg, P; Halpern, M; Irwin, K D; Jenness, T; Kelly, B D; MacIntosh, M J; Robson, E I; Scott, D; Ade, P A R; Atad-Ettedgui, E; Berry, D S; Craig, S C; Gao, X; Gibb, A G; Hilton, G C; Hollister, M I; Kycia, J B; Lunney, D W; McGregor, H; Montgomery, D; Parkes, W; Tilanus, R P J; Ullom, J N; Walther, C A; Walton, A J; Woodcraft, A L; Amiri, M; Atkinson, D; Burger, B; Chuter, T; Coulson, I M; Doriese, W B; Dunare, C; Economou, F; Niemack, M D; Parsons, H A L; Reintsema, C D; Sibthorpe, B; Smail, I; Sudiwala, R; Thomas, H S
2013-01-01
SCUBA-2 is an innovative 10000 pixel bolometer camera operating at submillimetre wavelengths on the James Clerk Maxwell Telescope (JCMT). The camera has the capability to carry out wide-field surveys to unprecedented depths, addressing key questions relating to the origins of galaxies, stars and planets. With two imaging arrays working simultaneously in the atmospheric windows at 450 and 850 microns, the vast increase in pixel count means that SCUBA-2 maps the sky 100-150 times faster than the previous SCUBA instrument. In this paper we present an overview of the instrument, discuss the physical characteristics of the superconducting detector arrays, outline the observing modes and data acquisition, and present the early performance figures on the telescope. We also showcase the capabilities of the instrument via some early examples of the science SCUBA-2 has already undertaken. In February 2012, SCUBA-2 began a series of unique legacy surveys for the JCMT community. These surveys will take 2.5 years and the ...
The James Clerk Maxwell Telescope Legacy Survey of Nearby Star-forming Regions in the Gould Belt
Ward-Thompson, D; Hatchell, J; Hogerheijde, M R; Bastien, P; Basu, S; Bonnell, I; Bowey, J; Brunt, C; Buckle, J; Butner, H; Cavanagh, B; Chrysostomou, A; Curtis, E; Davis, C J; Dent, W R F; van Dishoeck, E; Edmunds, M G; Fich, M; Fiege, J; Fissel, L; Friberg, P; Friesen, R; Frieswijk, W; Fuller, G A; Gosling, A; Graves, S; Greaves, J S; Helmich, F; Hills, R E; Holland, W S; Houde, M; Jayawardhana, R; Johnstone, D; Joncas, G; Kirk, H; Kirk, J M; Knee, L B G; Matthews, B; Matthews, H; Matzner, C; Moriarty-Schieven, G H; Naylor, D; Nutter, D; Padman, R; Plume, R; Rawlings, J M C; Redman, R O; Reid, M; Richer, J S; Shipman, R; Simpson, R J; Spaans, M; Stamatellos, D; Tsanis, Y; Viti, S; Weferling, B; White, G J; Whitworth, A P; Wouterloot, J; Yates, J; Zhu, M
2007-01-01
This paper describes a James Clerk Maxwell Telescope (JCMT) legacy survey that has been awarded roughly 500 hrs of observing time to be carried out from 2007 to 2009. In this survey we will map with SCUBA-2 (Submillimetre Common User Bolometer Array 2) almost all of the well-known low-mass and intermediate-mass star-forming regions within 0.5 kpc that are accessible from the JCMT. Most of these locations are associated with the Gould Belt. From these observations we will produce a flux-limited snapshot of star formation near the Sun, providing a legacy of images, as well as point-source and extended-source catalogues, over almost 700 square degrees of sky. The resulting images will yield the first catalogue of prestellar and protostellar sources selected by submillimetre continuum emission, and should increase the number of known sources by more than an order of magnitude. We will also obtain CO maps with the array receiver HARP (Heterodyne Array Receiver Programme), in three CO isotopologues, of a large typi...
James Clerk Maxwell: Life and science
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.
The Life of James Clerk Maxwell
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.
James Clerk Maxwell perspectives on his life and work
McCartney, Mark; Whitaker, Andrew
2014-01-01
James Clerk Maxwell (1831-1879) had a relatively brief, but remarkable life, lived in his beloved rural home of Glenlair, and variously in Edinburgh, Aberdeen, London and Cambridge. His scholarship also ranged wide - covering all the major aspects of Victorian natural philosophy. He was one of the most important mathematical physicists of all time, coming only after Newton and Einstein. In scientific terms his immortality is enshrined in electromagnetism and Maxwell's equations, but as this book shows, there was much more to Maxwell than electromagnetism, both in terms of his science and his wider life. Maxwell's life and contributions to science are so rich that they demand the expertise of a range of academics - physicists, mathematicians, and historians of science and literature - to do him justice. The various chapters will enable Maxwell to be seen from a range of perspectives. Chapters 1 to 4 deal with wider aspects of his life in time and place, at Aberdeen, King's College London and the Cavendish Labo...
James Clerk Maxwell's class of 1856/57
Reid, John S
2015-01-01
James Clerk Maxwell is known for his outstanding contributions to fundamental physics. These include providing the equations that govern electric and magnetic fields, establishing the basis of modern colourimetry, finding important relationships in thermodynamics, molecular science, mechanics, optics and astronomy. In his first Professorial chair in 1856 at the Marischal College and University of Aberdeen he undertook a substantial amount of teaching that laid the foundation for his later pedagogic output. This paper examines whom he taught, where his first students came from and what they did in later life, drawing material from a privately published memoir. Thumbnail portraits are included for 70% of his class. The analysis complements the usual emphasis on educational method and content. The data provide an interesting sociological survey of what Scottish University education was achieving in the middle of the 19th century and is presented as raw material for a wider enquiry.
James Clerk Maxwell, a precursor of system identification and control science
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.
The James Clerk Maxwell Telescope spectral legacy survey
Plume, R.; Fuller, G. A.; Helmich, F.; van der Tak, F. F. S.; Roberts, H.; Bowey, J.; Buckle, J.; Butner, H.; Caux, E.; Ceccarelli, C.; van Dishoeck, E. F.; Friberg, P.; Gibb, A. G.; Hatchell, J.; Hogerheijde, M. R.; Matthews, H.; Millar, T. J.; Mitchell, G.; Moore, T. J. T.; Ossenkopf, V.; Rawlings, J. M. C.; Richer, J.; Roellig, M.; Schilke, P.; Spaans, M.; Tielens, A. G. G. M.; Thompson, M. A.; Viti, S.; Weferling, B.; White, Glenn J.; Wouterloot, J.; Yates, J.; Zhu, M.
2007-01-01
Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes that can reveal the dynamics, physics, chemistry, and evolution of these regions, but our understanding of the molecular inventory of sources and how this is related to their physical st
The Molecular Origin of Turbulence in a Flowing Gas According to James Clerk Maxwell
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
The electric theories of J. Clerk Maxwell a historical and critical study
Duhem, Pierre Maurice Marie
2015-01-01
In this volume Pierre Duhem first gives an overview of 19th century electricity and magnetism. Next, he applies his keen historical, philosophical, and physical intuition to critiquing Maxwell's theories, especially his electromagnetic theory of light and the ad hoc introduction of displacement current, which he considers too much a product of the "esprit de géométrie" than the "esprit de finesse," as Pascal calls it. In this book, Duhem is guided by the principle that a theory that offers contradictions, even if the theory is posed by a genius, needs to be analysed and discussed until a c
James Clerk Maxwell e a unidade do mundo: modelos e metáforas na construção de teorias científicas
Carlos Fils Puig
2014-01-01
Esta é uma pesquisa sobre o uso de metáforas na construção de modelos por parte do físico escocês James Clerk Maxwell. O objetivo da pesquisa foi buscar compreender de que maneira o uso de metáforas e modelos é legítimo na ciência e em que medida contribui para seu sucesso. Além disso, busca compreender em que medida o uso de artifícios como modelos e analogias entre ramos distintos da ciência são impulsionadores de sucesso explicativo e preditivo da teoria do físico estudado. Explora as cre...
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.
Representing the Electromagnetic Field: How Maxwell's Mathematics Empowered Faraday's Field Theory
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…
Eisenberg, Bob
2016-01-01
Charges are everywhere because most atoms are charged. Chemical bonds are formed by electrons with their charge. Charges move and interact according to Maxwell's equations in space and in atoms where the equations of electrodynamics are embedded in Schroedinger's equation as the potential. Maxwell's equations are universal, valid inside atoms and between stars from times much shorter than those of atomic motion (0.1 femtoseconds) to years (32 mega-seconds). Maxwell's equations enforce the conservation of current. Analysis shows that the electric field can take on whatever value is needed to ensure conservation of current. The properties of matter rearrange themselves to satisfy Maxwell's equations and conservation of current. Conservation of current is as universal as Maxwell's equations themselves. Yet equations of electrodynamics find little place in the literature of material physics, chemistry, or biochemistry. Kinetic models of chemistry and Markov treatments of atomic motion are ordinary differential eq...
Kinsler, Paul; Thio, Timothy C Y; Trant, Claire; Kandapper, Navin
2012-01-01
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 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 "Tranformation Aquatics" version of the Maxwell's Fisheye lens [Tyc et al. 2011, Luneberg 1964] that is now well-known from transformation optics. These are transformation devices where wave propagation on the surface of a sphere is not modelled on an actual sphere, but in a flat device with carefully designed 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 opposing point in the device. 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] and partly as an accessible ...
Procedures Handbook for Elementary School IMC Clerks. Revised.
Allen, Christine
This training manual describes and explains the variety of tasks performed by library clerks in the Riverside (California) Unified School District's elementary school instructional media centers (IMCs). It is noted that the job responsibilities of these clerks fall into four areas with specific duties relating to each: maintenance of the…
Maxwell: A new vision of the world
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.
RESOLVING THE INNER JET STRUCTURE OF 1924-292 WITH THE EVENT HORIZON TELESCOPE
Energy Technology Data Exchange (ETDEWEB)
Lu Rusen; Fish, Vincent L.; Doeleman, Sheperd S. [Massachusetts Institute of Technology, Haystack Observatory, Route 40, Westford, MA 01886 (United States); Weintroub, Jonathan; Moran, James M.; Primiani, Rurik; Young, Ken H. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Bower, Geoffrey C.; Plambeck, Richard; Wright, Melvyn [Department of Astronomy, Radio Astronomy Laboratory, University of California Berkeley, 601 Campbell Hall, Berkeley, CA 94720-3411 (United States); Freund, Robert; Marrone, Daniel P. [Arizona Radio Observatory, Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721-0065 (United States); Friberg, Per; Tilanus, Remo P. J. [James Clerk Maxwell Telescope, Joint Astronomy Centre, 660 North A' ohoku Place, University Park, Hilo, HI 96720 (United States); Ho, Paul T. P.; Inoue, Makoto [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Honma, Mareki; Oyama, Tomoaki [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan); Krichbaum, Thomas P. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Shen Zhiqiang, E-mail: rslu@haystack.mit.edu [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); and others
2012-09-20
We present the first 1.3 mm (230 GHz) very long baseline interferometry model image of an active galactic nucleus (AGN) jet using closure phase techniques with a four-element array. The model image of the quasar 1924-292 was obtained with four telescopes at three observatories: the James Clerk Maxwell Telescope on Mauna Kea in Hawaii, the Arizona Radio Observatory's Submillimeter Telescope in Arizona, and two telescopes of the Combined Array for Research in Millimeter-wave Astronomy in California in 2009 April. With the greatly improved resolution compared with previous observations and robust closure phase measurement, the inner jet structure of 1924-292 was spatially resolved. The inner jet extends to the northwest along a position angle of -53 Degree-Sign at a distance of 0.38 mas from the tentatively identified core, in agreement with the inner jet structure inferred from lower frequencies, and making a position angle difference of {approx}80 Degree-Sign with respect to the centimeter jet. The size of the compact core is 0.15 pc with a brightness temperature of 1.2 Multiplication-Sign 10{sup 11} K. Compared with those measured at lower frequencies, the low brightness temperature may argue in favor of the decelerating jet model or particle-cascade models. The successful measurement of closure phase paves the way for imaging and time resolving Sgr A* and nearby AGNs with the Event Horizon Telescope.
Falconer, Isobel
2016-01-01
In 1877 James Clerk Maxwell and his student Donald McAlister refined Henry Cavendish's 1773 null experiment demonstrating the absence of electric charge inside a charged conductor. Such absence of charge was a mathematical prediction of the inverse square law, and both Cavendish and Maxwell took the experiment as verifying the law. However, Maxwell had previously expressed absolute conviction in the law, based on results of Faraday's. So what was the value to Maxwell of replicating Cavendish's experiment? This paper examines the mathematical and instrumental contexts of Maxwell's experiment. It situates the experiment in an assessment of the status of the inverse square law in the 1870s based on textbooks, Maxwell's drive to develop both an electrical programme and a "doctrine of method", and an investigation of the understanding of null methods in the 1870s. It demonstrates that he had previously shifted the evidential context of Faraday's work to suit his aims. It concludes that the experiment served both a...
Resolving the inner jet structure of 1924-292 with the EVENT HORIZON TELESCOPE
Lu, Ru-Sen; Weintroub, Jonathan; Doeleman, Sheperd S; Bower, Geoffrey C; Freund, Robert; Friberg, Per; Ho, Paul T P; Honma, Mareki; Inoue, Makoto; Krichbaum, Thomas P; Marrone, Daniel P; Moran, James M; Oyama, Tomoaki; Plambeck, Richard; Primiani, Rurik; Shen, Zhi-Qiang; Tilanus, Remo P J; Wright, Melvyn; Young, Ken H; Ziurys, Lucy M; Zensus, J Anton
2012-01-01
We present the first 1.3 mm (230 GHz) very long baseline interferometry model image of an AGN jet using closure phase techniques with a four-element array. The model image of the quasar 1924-292 was obtained with four telescopes at three observatories: the James Clerk Maxwell Telescope (JCMT) on Mauna Kea in Hawaii, the Arizona Radio Observatory's Submillimeter Telescope (SMT) in Arizona, and two telescopes of the Combined Array for Research in Millimeterwave Astronomy (CARMA) in California in April 2009. With the greatly improved resolution compared with previous observations and robust closure phase measurement, the inner jet structure of 1924-292 was spatially resolved. The inner jet extends to the northwest along a position angle of $-53^\\circ$ at a distance of 0.38\\,mas from the tentatively identified core, in agreement with the inner jet structure inferred from lower frequencies, and making a position angle difference of $\\sim 80^{\\circ}$ with respect to the cm-jet. The size of the compact core is 0.15\\...
Subjects great and small: Maxwell on Saturn's rings and kinetic theory.
Garber, Elizabeth
2008-05-28
Since 1890, James Clerk Maxwell's reputation has rested upon his theory of electromagnetism. However, during his lifetime he was recognized 'as the leading molecular scientist' of his generation. We will explore the foundation of his significance before 1890 using his work on the stability of Saturn's rings and the development of his kinetic theory of gases, and then briefly discuss the grounds for the change of his reputation.
V-TECS Guide for Bookkeeping/Accounting/Payroll Clerk.
Gregory, Margaret R.; Benson, Robert T.
This guide, an extension of the Vocational-Technical Education Consortium of States (V-TECS) catalog, includes such considerations as background information, decision-making skills, attitudes, and learning methods surrounding the occupations of bookkeeper/accountant/payroll clerk. The guide provides job-relevant task, performance objectives,…
Institute of Scientific and Technical Information of China (English)
A.I.Arbab
2013-01-01
A unified complex model of Maxwell's equations is presented.The wave nature of the electromagnetic field vector is related to the temporal and spatial distributions and the circulation of charge and current densities.A new vacuum solution is obtained,and a new transformation under which Maxwell's equations are invariant is proposed.This transformation extends ordinary gauge transformation to include charge-current as well as scalar-vector potential.An electric dipole moment is found to be related to the magnetic charges,and Dirac's quantization is found to determine an uncertainty relation expressing the indeterminacy of electric and magnetic charges.We generalize Maxwell's equations to include longitudinal waves.A formal analogy between this formulation and Dirac's equation is also discussed.
Maxwell's hypothesis reconsidered
Satheesh, S
2015-01-01
Maxwell's derivaion of the distributions of the velocities of molecules is based on the assumption that the velocity components in the three mutualy orthogonal directions are independent. Here we note that his assumption, the phase space is isotropic, in fact nullifies the effect of a variety of dependencies among the velocity componenets. Thus we can do away with the independence assumption. Further, we observe that his conclusion regarding distribution of the velocity components (Gaussian) remains true under a set of weaker assumptions.
Adaptation, Bacteria and Maxwell's Demons
Galajda, Peter; Keymer, Juan E.; Austin, Robert H.
2007-03-01
We propose a method to study the adaptation of bacterial populations with an asymmetric wall of Maxwell Demon openings. A Maxwell Demon opening is a funnel which is easier to enter than to leave. The interaction of swimming cells with such a Maxwell Demon Wall results in a population density separation, in apparent (but not real) violation of the Second Law of Thermodynamics, as we will show. Bacteria can be exposed to spatial challenges in order to move to e. g. higher food levels. The question we address in these experiments is: do the bacteria adapt and overcome the Maxwell Demon Wall?
James Clerk Maxwell Prize for Plasma Physics Talk: On Nonlinear Physics of Shear Alfv'en Waves
Chen, Liu
2012-10-01
Shear Alfv'en Waves (SAW) are electromagnetic oscillations prevalent in laboratory and nature magnetized plasmas. Due to its anisotropic propagation property, it is well known that the linear wave propagation and dispersiveness of SAW are fundamentally affected by plasma nonuniformities and magnetic field geometries; for example, the existence of continuous spectrum, spectral gaps, and discrete eigenmodes in toroidal plasmas. This talk will discuss the crucial roles that nonuniformity and geometry could also play in the physics of nonlinear SAW interactions. More specifically, the focus will be on the Alfv'enic state and its breaking up by finite compressibility, non-ideal kinetic effects, and geometry. In the case of compressibility, finite ion-Larmor-radius effects are shown to qualitatively and quantitatively modify the three-wave parametric decays via the ion-sound perturbations. In the case of geometry, the spontaneous excitation of zonal structures by toroidal Alfv'en eigenmodes is investigated; demonstrating that, for realistic tokamak geometries, zonal current dominates over zonal flow. [4pt] Present address: Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou, China.
Maxwell Optics III. Applications
Khan, S A
2002-01-01
A new formalism of beam-optics and polarization has been recently presented, based on an exact matrix representation of the Maxwell equations. This is described in Part-I and Part-II. In this Part, we present the application of the above formalism to the specific example of the axially symmetric graded index fiber. This formalism leads to the wavelength-dependent modifications of the six aberrations present in the traditional prescriptions and further gives rise to the remaining three aberrations permitted by the axial symmetry. Besides, it also gives rise to a wavelength-dependent image rotation. The three extra aberrations and the image rotation are not found in any of the traditional approaches.
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.
The Importance of a Role-Specific, In-Hospital Ward Clerk Education Program.
Kennedy, Maggie
2016-01-01
Ward clerks are essential members of the healthcare team, providing administrative and organizational support to acute care units and clinics. This role influences such matters as nurses' direct patient-care time, timeliness of patient discharges, and patient safety. To support ward clerks in the varying responsibilities and complex scope of this role, a formal orientation and ongoing education program is imperative. Whereas corporate orientation informs new employees of overall organizational processes, a ward clerk-specific workplace education program prepares individuals for the demands of the position, ultimately supporting the healthcare team and patient safety.
Maxwell stresses and dielectric materials
Kloos, Gerhard
2008-01-01
Electrostatic stresses are a fascinating field where materials science, continuum mechanics and electrical engineering all come together. This is one of the reasons why the study of these so-called Maxwell stresses is so interesting.This treatment of electrostatic Maxwell stresses is restricted to the macroscopic description of the phenomenon, but an attempt is made to provide readers with methods and results which will allow them to deal with cases of low material symmetry, as well as with the effect of viscoelasticity upon the material response. Non-standard orientation of the material samp
Maxwell's Demon and Data Compression
Hosoya, Akio; Shikano, Yutaka
2011-01-01
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 demon's memory after optimal data compression a la Shannon before the erasure.
Environmental Assessment: Disposition of Maxwell Heights Annex
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
Faraday, Maxwell, and the electromagnetic field how two men revolutionized physics
Forbes, Nancy
2014-01-01
The story of two brilliant nineteenth-century scientists who discovered the electromagnetic field, laying the groundwork for the amazing technological and theoretical breakthroughs of the twentieth century Two of the boldest and most creative scientists of all time were Michael Faraday (1791-1867) and James Clerk Maxwell (1831-1879). This is the story of how these two men - separated in age by forty years - discovered the existence of the electromagnetic field and devised a radically new theory which overturned the strictly mechanical view of the world that had prevailed since Newton's time. The authors, veteran science writers with special expertise in physics and engineering, have created a lively narrative that interweaves rich biographical detail from each man's life with clear explanations of their scientific accomplishments. Faraday was an autodidact, who overcame class prejudice and a lack of mathematical training to become renowned for his acute powers of experimental observation, technological skil...
Energy Technology Data Exchange (ETDEWEB)
Scully, Marlan O. [Texas A and M Univ., College Station, TX (United States); Princeton Univ., Princeton, NJ (United States); Scully, Robert J.
2010-07-01
Eagerly awaited, the new edition of this successful text is now available in paperback. Maxwell's Demon is a character in an 1867 thought experiment by the Scottish physicist James Clerk Maxwell, meant to raise questions about the second law of thermodynamics. This book explains the connection between Maxwell's Demon and the role of the observer and quantum eraser, showing that information science, thermodynamics and quantum physics are closely related. We often hear phrases like quantum weirdness and the strange world of the quantum. A fact that is not so widely appreciated is that quantum mechanics can (and does) shed light on problems such as the Maxwell Demon Paradox of thermodynamics, the seemingly spiritual nature of information, and even, perhaps, new insights into the existence of Mind. The common denominator of all this is the fact that information is a real physical quantity. Information is more than something just in our mind; it is the essence of, and in many ways more general than the concept of entropy. By focusing on entropy, information, and observation, the authors bring a unique perspective to this subject, and offer insight into the strange ways of the quantum which will not only fascinate scientists but lay persons as well. (orig.)
26 CFR 1.6050I-2 - Returns relating to cash in excess of $10,000 received as bail by court clerks.
2010-04-01
... cash receipt. For purposes of this section, a clerk is the clerk's office or the office, department... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Returns relating to cash in excess of $10,000... Returns relating to cash in excess of $10,000 received as bail by court clerks. (a) Reporting...
Armour, R S
2003-01-01
Requiring covariance of Maxwell's equations without {\\it a priori} imposing charge invariance allows for both spin-1 and spin-1/2 transformations of the complete Maxwell field and current. The spin-1/2 case yields new transformation rules, with new invariants, for all traditional Maxwell field and source quantities. The accompanying spin-1/2 representations of the Lorentz group employ the Lorentz metric, and consequently the primary invariants of the spin-1/2 Maxwell field are also spin-1 invariants, for example, $\\Phi^2 - {\\bf A}^2$, ${\\bf E}^2 - {\\bf B}^2 + 2i {\\bf E} \\bm{\\cdot} {\\bf B} - ({\\partial}_{0}{\\Phi} + {\\bm{\
National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.
This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)
Jimura, Akiyuki
1995-01-01
It is said that negatives play an important part in Chaucer's texts, to say nothing of other Middle English writings. The scholars only deal with the syntactic or grammatical use of negatives, but no one has yet explained the meanings of negative expressions. This paper, focusing on the speech of the characters, has investigated the negatives or negative expressions used in the speeches of the main characters Walter and Griselda and the Narrator in "The Clerk's Tale," The Canterbury Tales. It...
New family of Maxwell like algebras
Energy Technology Data Exchange (ETDEWEB)
Concha, P.K., E-mail: patillusion@gmail.com [Departamento de Ciencias, Facultad de Artes y Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Av. Padre Hurtado 750, Viña del Mar (Chile); Instituto de Ciencias Físicas y Matemáticas, Universidad Austral de Chile, Casilla 567, Valdivia (Chile); Durka, R., E-mail: remigiuszdurka@gmail.com [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Merino, N., E-mail: nemerino@gmail.com [Instituto de Física, Pontificia Universidad Católica de Valparaíso, Casilla 4059, Valparaíso (Chile); Rodríguez, E.K., E-mail: everodriguezd@gmail.com [Departamento de Ciencias, Facultad de Artes y Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Av. Padre Hurtado 750, Viña del Mar (Chile); Instituto de Ciencias Físicas y Matemáticas, Universidad Austral de Chile, Casilla 567, Valdivia (Chile)
2016-08-10
We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
Unconditionally stable integration of Maxwell's equations
Verwer, J.G.; Botchev, M.A.
2008-01-01
Numerical integration of Maxwell''s equations is often based on explicit methods accepting a stability step size restriction. In literature evidence is given that there is also a need for unconditionally stable methods, as exemplified by the successful alternating direction implicit-finite differenc
New family of Maxwell like algebras
Concha, P. K.; Durka, R.; Merino, N.; Rodríguez, E. K.
2016-08-01
We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
Las analogías en la formulación de la teoría electromagnética de la luz de Maxwell
Cachón Guillén, Vladimir
2016-01-01
Este trabajo se centra en los dos primeros artículos de James Clerk Maxwuell sobre las líneas de fuerza magnética. ¿Qué llevó a Maxwell a escribir sobre este tema, y cómo influyeron en él las circunstancias tecnológicas de su tiempo? Y, cobre todo, ¿cómo logró, a partir del empleo de analogías mecánicas, entender la naturaleza de los campos electromágneticos y concebir una teoría unificada del magnetismo, la electricidad y la luz? Se explora el proceso creativo de Maxwell y se intenta derivar...
Maxwell superalgebras and Abelian semigroup expansion
Energy Technology Data Exchange (ETDEWEB)
Concha, P.K.; Rodríguez, E.K. [Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Dipartimento di Scienza Applicata e Tecnologia (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, Via Pietro Giuria, 1, 10125 Torino (Italy)
2014-09-15
The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2) leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM{sup (N)} recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N). Moreover, we show that new minimal Maxwell superalgebras type sM{sub m+2} and their N-extended generalization can be obtained using the S-expansion procedure.
An axiomatic approach to Maxwell's equations
Heras, José A
2016-01-01
This paper suggests an axiomatic approach to Maxwell's equations. The basis of this approach is a theorem formulated for two sets of functions localized in space and time. If each set satisfies a continuity equation then the theorem provides an integral representation for each function. A corollary of this theorem yields Maxwell's equations with magnetic monopoles. It is pointed out that the causality principle and the conservation of electric and magnetic charges are the most fundamental physical axioms underlying these equations. Another application of the corollary yields Maxwell's equations in material media. The theorem is also formulated in the Minkowski space-time and applied to obtain the covariant form of Maxwell's equations with magnetic monopoles and the covariant form of Maxwell's equations in material media. The approach makes use of the infinite-space Green function of the wave equation and is therefore suitable for an advanced course in electrodynamics.
Maxwell superalgebras and Abelian semigroup expansion
Directory of Open Access Journals (Sweden)
P.K. Concha
2014-09-01
Full Text Available The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2 leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N. Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure.
Carr, J
2002-01-01
This review presents the scientific objectives and status of Neutrino Telescope Projects. The science program of these projects covers: neutrino astronomy, dark matter searches and measurements of neutrino oscillations. The two neutrino telescopes in operation: AMANDA and BAIKAL will be described together with the ANTARES neutrino telescope being built in the Mediterranean. (18 refs).
Green`s function of Maxwell`s equations and corresponding implications for iterative methods
Energy Technology Data Exchange (ETDEWEB)
Singer, B.S. [Macquarie Univ., Sydney (Australia); Fainberg, E.B. [Inst. of Physics of the Earth, Moscow (Russian Federation)
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.
Dirac and Maxwell equations in Split Octonions
Beradze, Revaz
2016-01-01
The split octonionic form of Dirac and Maxwell equations are found. In contrast with the previous attempts these equations are derived from the octonionic analyticity condition and also we use different basis of the 8-dimensional space of split octonions.
Maxwell National Wildlife Refuge: Comprehensive Conservation Plan
US Fish and Wildlife Service, Department of the Interior — This Comprehensive Conservation Plan (CCP) was written to guide management on Maxwell NWR for the next 15 years. This plan outlines the Refuge vision and purpose and...
What Maxwell's demon could do for you
Svozil, Karl
2011-01-01
In this highly speculative Letter it is argued that, under certain physical conditions, Maxwell's demon might be capable of breaking the second law of thermodynamics, thereby allowing a perpetual motion machine of the second kind, by accessing single particle capabilities.
New family of Maxwell like algebras
Directory of Open Access Journals (Sweden)
P.K. Concha
2016-08-01
Full Text Available We introduce an alternative way of closing Maxwell like algebras. We show, through a suitable change of basis, that resulting algebras are given by the direct sums of the AdS and the Maxwell algebras already known in the literature. Casting the result into the S-expansion method framework ensures the straightaway construction of the gravity theories based on a found enlargement.
Maxwell's equations of electrodynamics an explanation
Ball, David W
2012-01-01
Maxwell's Equations of Electrodynamics: An Explanation is a concise discussion of Maxwell's four equations of electrodynamics - the fundamental theory of electricity, magnetism, and light. It guides readers step-by-step through the vector calculus and development of each equation. Pictures and diagrams illustrate what the equations mean in basic terms. The book not only provides a fundamental description of our universe but also explains how these equations predict the fact that light is better described as "electromagnetic radiation."
On fictitious domain formulations for Maxwell's equations
DEFF Research Database (Denmark)
Dahmen, W.; Jensen, Torben Klint; Urban, K.
2003-01-01
We consider fictitious domain-Lagrange multiplier formulations for variational problems in the space H(curl: Omega) derived from Maxwell's equations. Boundary conditions and the divergence constraint are imposed weakly by using Lagrange multipliers. Both the time dependent and time harmonic...... formulations of the Maxwell's equations are considered. and we derive well-posed formulations for both cases. The variational problem that arises can be discretized by functions that do not satisfy an a-priori divergence constraint....
Venus - Maxwell Montes and Cleopatra Crater
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.
Supersymmetrization schemes of D=4 Maxwell algebra
Energy Technology Data Exchange (ETDEWEB)
Kamimura, Kiyoshi, E-mail: kamimura@ph.sci.toho-u.ac.jp [Department of Physics, Toho University, Funabashi 274-8510 (Japan); Lukierski, Jerzy [Institute of Theoretical Physics, Wroclaw University, pl. Maxa Borna 9, 50-204 Wroclaw (Poland)
2012-01-20
The Maxwell algebra, an enlargement of Poincare algebra by Abelian tensorial generators, can be obtained in arbitrary dimension D by the suitable contraction of O(D-1,1) Circled-Plus O(D-1,2) (Lorentz algebra Circled-Plus AdS algebra). We recall that in D=4 the Lorentz algebra O(3,1) is described by the realification Sp{sub R}(2|C) of complex algebra Sp(2|C) Asymptotically-Equal-To Sl(2|C) and O(3,2) Asymptotically-Equal-To Sp(4). We study various D=4N-extended Maxwell superalgebras obtained by the contractions of real superalgebras OSp{sub R}(2N-k;2|C) Circled-Plus OSp(k;4) (k=0,1,2, Horizontal-Ellipsis ,2N); (extended Lorentz superalgebra Circled-Plus extended AdS superalgebra). If N=1 (k=0,1,2) one arrives at three different versions of simple Maxwell superalgebra. For any fixed N we get 2N different superextensions of Maxwell algebra with n-extended Poincare superalgebras (1 Less-Than-Or-Slanted-Equal-To n Less-Than-Or-Slanted-Equal-To N) and the internal symmetry sectors obtained by suitable contractions of the real algebra O{sub R}(2N-k|C) Circled-Plus O(k). Finally the comments on possible applications of Maxwell superalgebras are presented.
Hanson, Mark D.; Szatmari, Peter; Eva, Kevin W.
2011-01-01
Objective: The authors evaluated the differential impact of clerk interest and participation in a Child and Adolescent Psychiatry (CAP) clerkship rotation upon psychiatry and pediatrics residency matches. Method: Authors studied clerks from the McMaster University M.D. program graduating years of 2005-2007. Participants were categorized as 1)…
An Alternative to Maxwell's Displacement Current
Wolsky, Alan M
2014-01-01
Though sufficient for local conservation of charge, we show that Maxwells displacement current is not necessary. An alternative to the Ampere Maxwell equation is exhibited and the alternative s electric and magnetic fields and scalar and vector potentials are expressed in terms of the charge and current densities. The alternative describes a theory in which action is instantaneous and so may provide a good approximation to Maxwells equations where and when the finite speed of light can be neglected. The result is reminiscent of the Darwin approximation which arose from the study classical charged point particles to order (v/c)2 in the Lagrangian. Unlike Darwin, this approach does not depend on the constitution of the electric current. Instead, this approach grows from a straightforward revision of the Ampere Equation which revision enforces the local conservation of charge.
Generalized Maxwell equations and charge conservation censorship
Modanese, G
2016-01-01
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 $S=\\partial_\\alpha A^\\alpha$, usually interpreted as a longitudinal wave component. By re-formulating 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 $\\partial_\\mu F^{\\mu \
Constraint-Preserving Scheme for Maxwell's Equations
Tsuchiya, Takuya
2016-01-01
We derive the discretized Maxwell's equations using the discrete variational derivative method (DVDM), calculate the evolution equation of the constraint, and confirm that the equation is satisfied at the discrete level. Numerical simulations showed that the results obtained by the DVDM are superior to those obtained by the Crank-Nicolson scheme. In addition, we study the two types of the discretized Maxwell's equations by the DVDM and conclude that if the evolution equation of the constraint is not conserved at the discrete level, then the numerical results are also unstable.
Studying the influence of workplace design on productivity of bank clerks
Directory of Open Access Journals (Sweden)
Seyed Abolfazl Zakerian
2016-06-01
Full Text Available Introduction: Workplace design is one of the factors that can influence comfort, performance, productivity and the health status of employees. The effects of this factor on human’s productivity and performance are studied in the domain of ergonomics. The impact of workplace design on workers’ productivity and performance can be determined by investigation of the quality of the design. The main purpose of the present study was to investigate the influence of workplace design on productivity of the bank clerks. Material and Method: Samples in this cross-sectional study were comprised of 150 employees of 22 different branches of a bank in Tehran city. Data collection tools included demographic questionnaire and a questionnaire related to the effects of workplace design on employees’ productivity, developed by Hameed and colleagues. Correlation and regression statistical tests were used in order to analyze data. Result: According to the results, the mean (±SD for age and job tenure of participants were 37.2(±6 and 13(±7 years, respectively. Of the surveyed demographic features, a significant relationship was observed between age and scores belonging to the temperature and furniture (P-value<0.05. In addition, there was a significant association between employees’ productivity and the noise (P-value=0.044 and spatial arrangement of environment (P-value=0.048. Conclusion: Overall, appropriate and high quality design of work environment can improve productivity of bank clerks. In other words, employees’ productivity can be enhanced by comfortable and ergonomic design of working environment and also by considering their needs.
Redesigning a clinical mentoring program for improved outcomes in the clinical training of clerks
Directory of Open Access Journals (Sweden)
Chia-Der Lin
2015-09-01
Full Text Available Introduction: Mentorship has been noted as critical to medical students adapting to clinical training in the medical workplace. A lack of infrastructure in a mentoring program might deter relationship building between mentors and mentees. This study assessed the effect of a redesigned clinical mentoring program from the perspective of clerks. The objective was to assess the benefits of the redesigned program and identify potential improvements. Methods: A redesigned clinical mentoring program was launched in a medical center according to previous theoretical and practical studies on clinical training workplaces, including the elements of mentor qualifications, positive and active enhancers for mentor–mentee relationship building, the timing of mentoring performance evaluation, and financial and professional incentives. A four-wave web survey was conducted, comprising one evaluation of the former mentoring program and three evaluations of the redesigned clinical mentoring program. Sixty-four fifth-year medical students in clerkships who responded to the first wave and to at least two of the three following waves were included in the study. A structured and validated questionnaire encompassing 15 items on mentor performance and the personal characteristics of the clerks was used. Mixed linear models were developed for repeated measurements and to adjust for personal characteristics. Results: The results revealed that the redesigned mentoring program improved the mentors’ performance over time for most evaluated items regarding professional development and personal support provided to the mentees. Conclusions: Our findings serve as an improved framework for the role of the institution and demonstrate how institutional policies, programs, and structures can shape a clinical mentoring program. We recommend the adoption of mentorship schemes for other cohorts of medical students and for different learning and training stages involved in becoming a
Maxwell's electromagnetic theory and special relativity.
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.
Time-Reversible Maxwell’s Demon
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
Maxwell Equations for Slow-Moving Media
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.
NEGATIVE MAXWELL-STEFAN DIFFUSION-COEFFICIENTS
KRAAIJEVELD, G; WESSELINGH, JA
1993-01-01
The existence of negative Maxwell-Stefan diffusivities is investigated. For the case where the diffusion coefficients are taken to be composition dependent, it is found that the theory of irreversible thermodynamics does not require all diffusivities to be positive definite. This theoretical result
Maxwell and the classical wave particle dualism.
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.
Length-biased Weighted Maxwell Distribution
Directory of Open Access Journals (Sweden)
Kanak Modi
2015-12-01
Full Text Available The concept of length-biased distribution can be employed in development of proper models for life-time data. In this paper, we develop the length-biased form of Weighted Maxwell distribution (WMD. We study the statistical properties of the derived distribution including moments, moment generating function, hazard rate, reverse hazard rate, Shannon entropy and estimation of parameters
Energy Technology Data Exchange (ETDEWEB)
Lampton, Michael L.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Bercovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro, R.; Ealet, A.; Ellis,R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar,A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland,S.E.; Huterer, D.; Karcher, A.; Kim, A.G.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder, E.V.; Loken,S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi,H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto,E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.; Wang, G.
2002-07-29
The SuperNova/Acceleration Probe (SNAP) mission will require a two-meter class telescope delivering diffraction limited images spanning a one degree field in the visible and near infrared wavelength regime. This requirement, equivalent to nearly one billion pixel resolution, places stringent demands on its optical system in terms of field flatness, image quality, and freedom from chromatic aberration. We discuss the advantages of annular-field three-mirror anastigmat (TMA) telescopes for applications such as SNAP, and describe the features of the specific optical configuration that we have baselined for the SNAP mission. We discuss the mechanical design and choice of materials for the telescope. Then we present detailed ray traces and diffraction calculations for our baseline optical design. We briefly discuss stray light and tolerance issues, and present a preliminary wavefront error budget for the SNAP Telescope. We conclude by describing some of tasks to be carried out during the upcoming SNAP research and development phase.
What physics is encoded in Maxwell's equations?
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.
Maxwell Optics I. An exact matrix representation of the Maxwell equations in a medium
Khan, S A
2002-01-01
Matrix representations of the Maxwell equations are well-known. However, all these representations lack an exactness or/and are given in terms of a {\\em pair} of matrix equations. We present a matrix representation of the Maxwell equation in presence of sources in a medium with varying permittivity and permeability. It is shown that such a representation necessarily requires $8 \\times 8$ matrices and an explicit representation for them is presented.
Maxwell's Daemon: information versus particle statistics.
Plesch, Martin; Dahlsten, Oscar; Goold, John; Vedral, Vlatko
2014-11-11
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.
Classes of exact Einstein Maxwell solutions
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.
Maxwell-Chern-Simons Casimir Effect
Milton, K A
1992-01-01
In odd-dimensional spaces, gauge invariance permits a Chern-Simons mass term for the gauge fields in addition to the usual Maxwell-Yang-Mills kinetic energy term. We study the Casimir effect in such a (2+1)-dimensional Abelian theory. For the case of parallel conducting lines the result is the same as for a scalar field. For the case of circular boundary conditions the results are completely different, with even the sign of the effect being opposite for Maxwell-Chern-Simons fields and scalar fields. We further examine the effect of finite temperature. The Casimir stress is found to be attractive at both low and high temperature. Possibilities of observing this effect in the laboratory are discussed.
Maxwell Duality, Lorentz Invariance, and Topological Phase
Dowling, J P; Franson, J D; Dowling, Jonathan P.; Williams, Colin P.
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. We also elucidate Lorentz transformations that allow these effects to be understood in an intuitive fashion in the rest frame of the moving quantum particle. Finally, we propose a realistic set up for measuring and interpreting the He-McKellar-Wilkens phase directly in an experiment.
Dual symmetry in a generalized Maxwell theory
Brandt, F T; McKeon, D G C
2016-01-01
We examine Podolsky's electrodynamics, which is noninvariant under the usual duality transformation. We deduce a generalization of Hodge's star duality, which leads to a dual gauge field and restores to a certain extent the dual symmetry. The model becomes fully dual symmetric asymptotically when it reduces to the Maxwell theory. We argue that this strict dual symmetry directly implies the existence of the basic invariants of the electromagnetic fields.
The Pseudo-Maxwell Equations Revisited
Stavroudis, Orestes N.
1982-02-01
The so-called pseudo-Maxwell are a set of partial differential eauations that strongly resemble the Maxwell equations, yet are based only on Fermat's principle, the idea of an orthotomic system of rays, and certain theorems from differential gecmetry. From Fermat's principle, applying the Euler equation from the variational calculus, one obtains the ray equation whose solutions describe ray paths in an inhomogeneous medium. We define an aggregate of such rays as an orthotomic system if it is possible to find a sur-face orthogonal to all rays in the aggregate. Making use of the Frenet equations from differential geometry, one may derive relationships between certain geometrical vectors and their derivatives. These are the pseudo-Maxwell equations. Their existence is' paradoxical. Are they merely a mathematical artifact, an accidental quirk of the notation we are accustomed to use? Or do they indicate that there is more geometry lurking in the physics of electricity and magnetism than we ever dreamed of in our philosophies?
Mathematics and Maxwell's equations
Energy Technology Data Exchange (ETDEWEB)
Boozer, Allen H, E-mail: ahb17@columbia.ed [Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY 10027 (United States)
2010-12-15
The universality of mathematics and Maxwell's equations is not shared by specific plasma models. Computations become more reliable, efficient and transparent if specific plasma models are used to obtain only the information that would otherwise be missing. Constraints of high universality, such as those from mathematics and Maxwell's equations, can be obscured or lost by integrated computations. Recognition of subtle constraints of high universality is important for (1) focusing the design of control systems for magnetic field errors in tokamaks from perturbations that have little effect on the plasma to those that do, (2) clarifying the limits of applicability to astrophysics of computations of magnetic reconnection in fields that have a double periodicity or have B-vector =0 on a surface, as in a Harris sheet. Both require a degree of symmetry not expected in natural systems. Mathematics and Maxwell's equations imply that neighboring magnetic field lines characteristically separate exponentially with distance along a line. This remarkably universal phenomenon has been largely ignored, though it defines a trigger for reconnection through a critical magnitude of exponentiation. These and other examples of the importance of making distinctions and understanding constraints of high universality are explained.
Directory of Open Access Journals (Sweden)
Héctor Torres-Silva
2008-11-01
Full Text Available This work deals with the problem of the construction of the Lagrange functional for an electromagnetic field. The generalised Maxwell equations for an electromagnetic field in free space are introduced. The main idea relies on the change of Lagrange function under the integral action. Usually, the Lagrange functional which describes the electromagnetic field is built with the quadrate of the electromagnetic field tensor . Such a quadrate term is the reason, from a mathematical point of view, for the linear form of the Maxwell equations in free space. The author does not make this assumption and nonlinear Maxwell equations are obtained. New material parameters of free space are established. The equations obtained are quite similar to the well-known Maxwell equations. The energy tensor of the electromagnetic field from a chiral approach to the Born Infeld Lagrangian is discussed in connection with the cosmological constant.Se aborda el problema de la construcción de la funcional de Lagrange de un campo electromagnético. Se introducen las ecuaciones generalizadas de Maxwell de un campo electromagnético en el espacio libre. La idea principal se basa en el cambio de función de Lagrange en virtud de la acción integral. Por lo general, la funcional de lagrange, que describe el campo electromagnético, se construye con el cuadrado del tensor de campo electromagnético. Ese término cuadrático es la razón, desde un punto de vista matemático, de la forma lineal de las ecuaciones de Maxwell en el espacio libre. Se obtienen las ecuaciones no lineales de Maxwell sin considerar esta suposición. Las ecuaciones de Maxwell obtenidas son bastante similares a las conocidas ecuaciones de Maxwell. Se analiza el tensor de energía del campo electromagnético en un enfoque quiral de la Lagrangiana de Born Infeld en relación con la constante cosmológica.
Selecting Your First Telescope.
Harrington, Sherwood
1982-01-01
Designed for first-time telescope purchasers, provides information on how a telescope works; major telescope types (refractors, reflectors, compound telescopes); tripod, pier, altazimuth, and equatorial mounts; selecting a telescope; visiting an astronomy club; applications/limitations of telescope use; and tips on buying a telescope. Includes a…
Maxwell-Chern-Simons Casimir entropy%Maxwell-Chern-Simons规范场的Casimir熵
Institute of Scientific and Technical Information of China (English)
李长松; 刘畅; 姜文英; 杨慧; 潘淑梅; 郑泰玉
2013-01-01
利用泛函积分量子化方法研究了2个平行的、理想的金属线之间在有限温度下Maxwell-Chern-Simons规范场的Casimir熵.分别讨论了低温和高温2种极限情况下的Casimir熵.给出了Maxwell-Chern-Simons规范场的质量为零时的高温和低温的Casimir熵的表达式.结果显示,在绝对零度下,Maxwell-Chern-Simons规范场的Casimir熵等于零,满足热力学第三定律.
Maxwell Optics II. An Exact Formalism
Khan, S A
2002-01-01
We present a formalism for light optics starting with the Maxwell equations and casting them into an exact matrix form taking into account the spatial and temporal variations of the permittivity and permeability. This $8 \\times 8$ matrix representation is used to construct the optical Hamiltonian. This has a close analogy with the algebraic structure of the Dirac equation, enabling the use of the rich machinery of the Dirac electron theory. We get interesting wavelength-dependent contributions which can not be obtained in any of the traditional approaches.
Generating Solutions to the Einstein - Maxwell Equations
Contopoulos, I G; Kleidis, K; Papadopoulos, D B; Witten, L
2015-01-01
The Einstein-Maxwell (E-M) equations in a curved spacetime that admits at least one Killing vector are derived, from a Lagrangian density adapted to symmetries. In this context, an auxiliary space of potentials is introduced, in which, the set of potentials associated to an original (seed) solution of the E-M equations are transformed to a new set, either by continuous transformations or by discrete transformations. In this article, continuous transformations are considered. Accordingly, originating from the so-called $\\gamma_A$-metric, other exact solutions to the E-M equations are recovered and discussed.
Maxwell-like Lagrangians for higher spins
Campoleoni, Andrea
2012-01-01
We show how implementing invariance under divergence-free gauge transformations leads to a remarkably simple Lagrangian description of massless bosons of any spin. Our construction covers both flat and (A)dS backgrounds and extends to tensors of arbitrary mixed-symmetry type. Irreducible and traceless fields produce single-particle actions, while whenever trace constraints can be dispensed with the resulting Lagrangians display the same reducible, multi-particle spectra as those emerging from the tensionless limit of free open-string field theory. For all explored options the corresponding kinetic operators take essentially the same form as in the spin-one, Maxwell case.
Maxwell Chern Simons Theory in a Geometric Representation
Leal, L C
2001-01-01
We quantize the Maxwell Chern Simons theory in a geometric representation that generalizes the Abelian Loop Representation of Maxwell theory. We find that in the physical sector, the model can be seen as the theory of a massles scalar field with a topological interaction that enforces the wave functional to be multivalued. This feature allows to relate the Maxwell Chern Simons theory with the quantum mechanics of particles interacting through a Chern Simons field
On the experimental foundations of the Maxwell equations
Haugan, Mark P
2000-01-01
We begin by reviewing the derivation of generalized Maxwell equations from anoperational definition of the electromagnetic field and the most basic notionsof what constitutes a dynamical field theory. These equations encompass thefamiliar Maxwell equations as a special case but, in other cases, can predictbirefringence, charge non-conservation, wave damping and other effects that thefamiliar Maxwell equations do not. It follows that observational constraints onsuch effects can restrict the dynamics of the electromagnetic field to be verylike the familiar Maxwellian dynamics, thus, providing an empirical foundationfor the Maxwell equations. We discuss some specific observational results thatcontribute to that foundation.
Comparing Teaching Approaches About Maxwell's Displacement Current
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.
On Feynman's proof of the Maxwell equations
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.
Chern-Simons Supergravity in D=3 and Maxwell superalgebras
Concha, P K; Rodríguez, E K; Salgado, P
2015-01-01
We present the construction of the $D=3$ Chern-Simons supergravity action from the Maxwell superalgebra $s\\mathcal{M}$, which can be obtained from the anti-De Sitter superalgebra by combining the abelian semigroup expansion procedure and the In\\"{o}n\\"{u}-Wigner contraction. \\ The Chern-Simons supergravity action from a generalized Maxwell superalgebra is also introduced.
Maxwell Equations and the Redundant Gauge Degree of Freedom
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…
Maxwells ligninger og de elektromagnetiske bølger
DEFF Research Database (Denmark)
Mandrup, Lars
2000-01-01
Dette kompendie i Videregående Elektrodynamik omhandler Maxwells ligninger på differential¬form og disses anvendelse til at beskrive de elektromagnetiske bølger og deres egenskaber. Udgangspunktet for kompendiet er Maxwells ligninger på integralform, som det forudsættes, at læseren er bekendt med...
Odhner, Jefferson E.
2016-07-01
Holographic optical elements (HOEs) work on the principal of diffraction and can in some cases replace conventional optical elements that work on the principal of refraction. An HOE can be thinner, lighter, can have more functionality, and can be lower cost than conventional optics. An HOE can serve as a beam splitter, spectral filter, mirror, and lens all at the same time. For a single wavelength system, an HOE can be an ideal solution but they have not been widely accepted for multispectral systems because they suffer from severe chromatic aberration. A refractive optical system also suffers from chromatic aberration but it is generally not as severe. To color correct a conventional refractive optical system, a flint glass and a crown glass are placed together such that the color dispersion of the flint and the crown cancel each other out making an achromatic lens (achromat) and the wavelengths all focus to the same point. The color dispersion of refractive lenses and holographic lenses are opposite from each other. In a diffractive optical system, long wavelengths focus closer (remember for HOEs: RBM "red bends more") than nominal focus while shorter wavelengths focus further out. In a refractive optical system, it is just the opposite. For this reason, diffractives can be incorporated into a refractive system to do the color correction and often cut down on the number of optical elements used [1.]. Color correction can also be achieved with an all-diffractive system by combining a holographic optical element with its conjugate. In this way the color dispersion of the first holographic optical element can be cancelled by the color dispersion of the second holographic optic. It is this technique that will be exploited in this paper to design a telescope made entirely of holographic optical elements. This telescope could be more portable (for field operations) the same technique could be used to make optics light enough for incorporation into a UAV.
Algebraically special Einstein-Maxwell fields
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.
Mechanical Weyl Modes in Topological Maxwell Lattices
Rocklin, D. Zeb; Chen, Bryan Gin-ge; Falk, Martin; Vitelli, Vincenzo; Lubensky, T. C.
2016-04-01
We show that two-dimensional mechanical lattices can generically display topologically protected bulk zero-energy phonon modes at isolated points in the Brillouin zone, analogs of massless fermion modes of Weyl semimetals. We focus on deformed square lattices as the simplest Maxwell lattices, characterized by equal numbers of constraints and degrees of freedom, with this property. The Weyl points appear at the origin of the Brillouin zone along directions with vanishing sound speed and move away to the zone edge (or return to the origin) where they annihilate. Our results suggest a design strategy for topological metamaterials with bulk low-frequency acoustic modes and elastic instabilities at a particular, tunable finite wave vector.
Another Way To Realize Maxwell's Demon
Fu, X; Fu, Xinyong; Fu, Zitao
2005-01-01
This is another approach to realize Maxwell's demon hypothesis. Two Ag-O-Cs thermal electron ejectors, A and B, are settled in a vacuum tube. A non-uniform magnetic field exerted on the tube provides a one-way channel for the thermal electrons. Ejector A, losing electrons, charges positively, while ejector B, getting electrons, charges negatively, resulting in an electric voltage. In flying from A to B, the speed of the electrons decreases, and part of their thermal kinetic energy converts into electric potential energy. Thus, the temperature of the whole electron tube drops down slightly, and that can be compensated by the heat attracted from the ambient air. The device can provide a small but macroscopic power to an external load, violating Kelvin's statement of the second law.
Spherical harmonics, invariant theory and Maxwell's poles
Dowker, J S
2008-01-01
I discuss the relation between harmonic polynomials and invariant theory and show that homogeneous, harmonic polynomials correspond to ternary forms that are apolar to a base conic (the absolute). The calculation of Schlesinger that replaces such a form by a polarised binary form is reviewed. It is suggested that Sylvester's theorem on the uniqueness of Maxwell's pole expression for harmonics is renamed the Clebsch-Sylvester theorem. The relation between certain constructs in invariant theory and angular momentum theory is enlarged upon and I resurrect the Joos--Weinberg matrices. Hilbert's projection operators are considered and their generalisations by Story and Elliott are related to similar, more recent constructions in group theory and quantum mechanics, the ternary case being equivalent to SU(3).
Maxwell's demon through the looking glass
Silagadze, Z K
2006-01-01
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.
Maxwell's Demon Through the Looking Glass
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.
Maxwell's demon in the quantum world
Kim, Sang Wook; De Liberato, Simone; Ueda, Masahito
2010-01-01
Maxwell's demon (MD) is a hypothetical being of intelligence that was conceived to illuminate possible limitations of the second law of thermodynamics. Leo Szilard made a classical analysis of the MD, considering an idealized heat engine with one molecule gas, and directly associated the information acquired by measurement with physical entropy to save the second law. Although Szilard's engine (SZE) deals with a truly quantum-mechanical object, namely an engine with a single molecule, surprisingly its fully quantum-mechanical analysis has been elusive except for the measurement process. Here, we present the first complete quantum analysis of the SZE, and report two important findings. First, we derive an analytic expression of the quantum-mechanical work performed by a quantum SZE containing an arbitrary number of molecules, where it is crucial to regard the process of insertion or removal of a wall as a legitimate thermodynamic process. Secondly, we find that the indistinguishability of quantum identical par...
A Maxwell demon to cool atoms; Un demon de Maxwell pour refroidir les atomes
Energy Technology Data Exchange (ETDEWEB)
Raizen, M. [Texas A Univ., TX (United States)
2011-07-15
As usual methods to cool gases down to a temperature close to the absolute zero are only efficient for some species, a combination of two techniques is used to cool almost all atoms, and even some molecules. An inverted magnetic rail gun first slows down atoms. Cooling is then carried on by means of a technique inspired by the 'Maxwell demon' imagined in 1780. Applications under investigation are ranging from the study of elementary particle properties to isotope separation
Incompressible Navier-Stokes equation from Einstein-Maxwell and Gauss-Bonnet-Maxwell theories
Energy Technology Data Exchange (ETDEWEB)
Niu Chao [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Tian Yu, E-mail: ytian@gucas.ac.cn [College of Physical Sciences, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Wu Xiaoning [Institute of Mathematics, Academy of Mathematics and System Science, CAS, Beijing 100190 (China); Hua Loo-Keng Key Laboratory of Mathematics, CAS, Beijing 100190 (China); Ling Yi [Center for Relativistic Astrophysics and High Energy Physics, Department of Physics, Nanchang University, 330031 (China); Institute of Mathematics, Academy of Mathematics and System Science, CAS, Beijing 100190 (China)
2012-05-23
The dual fluid description for a general cutoff surface at radius r=r{sub c} outside the horizon in the charged AdS black brane bulk space-time is investigated, first in the Einstein-Maxwell theory. Under the non-relativistic long-wavelength expansion with parameter {epsilon}, the coupled Einstein-Maxwell equations are solved up to O({epsilon}{sup 2}). The incompressible Navier-Stokes equation with external force density is obtained as the constraint equation at the cutoff surface. For non-extremal black brane, the viscosity of the dual fluid is determined by the regularity of the metric fluctuation at the horizon, whose ratio to entropy density {eta}/s is independent of both the cutoff r{sub c} and the black brane charge. Then, we extend our discussion to the Gauss-Bonnet-Maxwell case, where the incompressible Navier-Stokes equation with external force density is also obtained at a general cutoff surface. In this case, it turns out that the ratio {eta}/s is independent of the cutoff r{sub c} but dependent on the charge density of the black brane.
Directory of Open Access Journals (Sweden)
Gordon Morris
2014-07-01
Full Text Available The research discussed in this paper was prompted by the writer’s interest in the roles of England’s small country (“market” towns. It has two aims: first, to discover the extent to which the work programmes announced in the British government’s Rural White Paper (RWP 2000 (DETR-MAFF 2000 are recognised by town clerks, and second, to find out what town councils are doing, either on their own, or with others, and to gauge the potential and desire that they have for a greater degree of autonomy. In both cases the data was gathered from an online questionnaire sent to town clerks.
Holographic superconductor models with the Maxwell field strength corrections
Pan, Qiyuan; Wang, Bin
2011-01-01
We study the effect of the quadratic field strength correction to the usual Maxwell field on the holographic dual models in the backgrounds of AdS black hole and AdS soliton. We find that in the black hole background, the higher correction to the Maxwell field makes the condensation harder to form and changes the expected relation in the gap frequency. This effect is similar to that caused by the curvature correction. However, in the soliton background we find that different from the curvature effect, the correction to the Maxwell field does not influence the holographic superconductor and insulator phase transition.
Generalized gravitational entropy of interacting scalar field and Maxwell field
Directory of Open Access Journals (Sweden)
Wung-Hong Huang
2014-12-01
Full Text Available 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.
General proof of entropy principle in Einstein-Maxwell theory
Fang, Xiongjun
2015-01-01
We consider a static self-gravitating charged perfect fluid system in the Einstein-Maxwell theory. Assume Maxwell's equation and the Einstein constraint equation are satisfied, and the temperature of the fluid obeys Tolman's law. Then we prove that the total entropy of the fluid achieves an extremum implies other components of Einstein's equation for any variations of metric and electrical potential with fixed boundary values. Conversely, if Einstein's equation and Maxwell's equations hold, the total entropy achieves an extremum. Our work suggests that the maximum entropy principle is consistent with Einstein's equation when electric field is taken into account.
Generalized gravitational entropy of interacting scalar field and Maxwell field
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.
Generalized gravitational entropy of interacting scalar field and Maxwell field
Energy Technology Data Exchange (ETDEWEB)
Huang, Wung-Hong, E-mail: whhwung@mail.ncku.edu.tw
2014-12-12
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.
KOMPUTASI DISTRIBUSI NEUTRON DALAM STATISTIK MAXWELL BOLTZMANN
Directory of Open Access Journals (Sweden)
Tuti Purwoningsih
2013-03-01
Full Text Available The migration of neutron is arranged by some probability distributions such as probability of spread distribution, probability of distance distribution, probability of energy distribution and probability of flux distribution. One application of these pattern distributions is modelling the reaction between neutron and elements which compose the tissue related to the absorption of neutron in brain cancer tissues. This article explores computation analysis of pattern of distribution of neutron flux in a reactor system. Variables were the amount of neutron simulated and the depth of cylindrical reactor system. Simulations showed that 20-120 minutes was needed in executing 100,000 neutrons to build the distribution pattern of neutrons flux. This pattern was also depended on the depth of the system. In all depths, the peak of neutron flux distribution pattern was in the 3rd bin. Comparison between this simulations and experiment results in literatures showed that by analyzing the simulation of the distribution of neutron flux, a Poisson distribution which follows the Maxwell-Boltzmann was resulted. Perpindahan neutron diatur dengan beberapa peluang distribusi, seperti peluang distribusi sudut hamburan, peluang distribusi jarak perpindahan, peluang distribusi energi transfer, serta peluang distribusi fluks neutron. Salah satu aplikasi dari pola distribusi ini adalah pemodelan reaksi antara neutron dengan elemen-elemen penyusun jaringan yang terkait dengan serapan neutron dan dosis yang terserap oleh jaringan tumor otak pada terapi BNCT (Boron Neutron Capture Therapy. Dalam penelitian ini dibahas analisis komputasi tentang pola distribusi fluks neutron dalam suatu sistem reaktor. Variabel dalam penelitian ini adalah banyaknya neutron yang disimulasikan, serta kedalaman sistem reaktor yang dalam penelitian ini menggunakan sistem reaktor berbentuk silinder. Hasil simulasi menunjukkan bahwa dengan neutron sebanyak 100.000 diperlukan waktu eksekusi sekitar
Two Mathematically Equivalent Versions of Maxwell's Equations
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.
Analytical BPS Maxwell-Higgs Vortices
Directory of Open Access Journals (Sweden)
R. Casana
2014-01-01
Full Text Available We have established a prescription for the calculation of analytical vortex solutions in the context of generalized Maxwell-Higgs models whose overall dynamics is controlled by two positive functions of the scalar field, namely, fϕ and wϕ. We have also determined a natural constraint between these functions and the Higgs potential Uϕ, allowing the existence of axially symmetric Bogomol'nyi-Prasad-Sommerfield (BPS solutions possessing finite energy. Furthermore, when the generalizing functions are chosen suitably, the nonstandard BPS equations can be solved exactly. We have studied some examples, comparing them with the usual Abrikosov-Nielsen-Olesen (ANO solution. The overall conclusion is that the analytical self-dual vortices are well-behaved in all relevant sectors, strongly supporting the consistency of the respective generalized models. In particular, our results mimic well-known properties of the usual (numerical configurations, as localized energy density, while contributing to the understanding of topological solitons and their description by means of analytical methods.
Quantum Maxwell's Demon in Thermodynamic Cycles
Dong, H; Sun, C P
2010-01-01
We study the physical mechanism of Maxwell's Demon (MD) helping to do extra work in thermodynamic cycles, by describing measurement of position, insertion of wall and information erasing of MD in a quantum mechanical fashion. The heat engine is exemplified with one molecule confined in an infinitely deep square potential inserted with a movable solid wall, while the MD is modeled as a two-level system (TLS) for measuring and controlling the motion of the molecule. It is discovered that the the MD with quantum coherence or on a lower temperature than that of the heat bath of the particle would enhance the ability of the whole work substance formed by the system plus the MD to do work outside. This observation reveals that the role of the MD essentially is to drive the whole work substance being off equilibrium, or equivalently working with an effective temperature difference. The elaborate studies with this model explicitly reveal the effect of finite size off the classical limit or thermodynamic limit, which ...
Quasi-Maxwell interpretation of the spin-curvature coupling
Natario, J
2007-01-01
We write the Mathisson-Papapetrou equations of motion for a spinning particle in a stationary spacetime using the quasi-Maxwell formalism and give an interpretation of the coupling between spin and curvature.
Modeling anisotropic Maxwell-Jüttner distributions: derivation and properties
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.
The Trail Inventory of Maxwell NWR [Cycle 2
US Fish and Wildlife Service, Department of the Interior — The purpose of this report is to create a baseline inventory of all non-motorized trails on Maxwell National Wildlife Refuge. Trails in this inventory are eligible...
Distribución de probabilidad de Maxwell transmutada
Directory of Open Access Journals (Sweden)
Yuri A. Iriarte
2014-12-01
Full Text Available En este artículo introducimos una extensión de la distribución de probabilidad de Maxwell. Esta extensión se genera utilizando el mapa de transmutación de rango cuadrático, estudiado por Shaw y Buckley en [13], considerando como función base la función de distribución acumulada del modelo de Maxwell. Estudiamos propiedades probabilísticas, realizamos inferencia estadística y estudiamos una aplicación con datos reales Abstract. In this paper we introduce an extension of the Maxwell probability distribution. This extension is generated using the quadratic rank transmutation map studied by Shaw and Buckley in [13], considering as the basis function the cumulative distribution function of the Maxwell model. We study probabilistic properties, we perform statistical inference and study an application with real data.
Singularity-free interaction in dilaton-Maxwell electrodynamics
Kechkin, O. V.; Mosharev, P. A.
2016-09-01
An effective potential is created for the dynamics of a test particle, which preserves dilatation symmetry for nonlinear static dilaton-Maxwell background. It is found that the central interaction in this theory is singularity-free everywhere; it vanishes at short distances and demonstrates Coulomb behavior far from the source. It is shown that static and spherically symmetric source behaves like a soliton: it has the finite energy characteristics that are inversely proportional to the dilaton-Maxwell coupling constant.
Variational formulations of guiding-center Vlasov-Maxwell theory
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.
Compressible Navier-Stokes Equations with Revised Maxwell's Law
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.
Maxwell and Dirac theories as an already unified theory
1995-01-01
In this paper we formulate Maxwell and Dirac theories as an already unified theory (in the sense of Misner and Wheeler). We introduce Dirac spinors as "Dirac square root" of the Faraday bivector, and use this in order to find a spinorial representation of Maxwell equations. Then we show that under certain circunstances this spinor equation reduces to an equation formally identical to Dirac equation. Finally we discuss certain conditions under which this equation can be really interpreted as D...
Hopkins in the Age of Maxwell Hopkins à l’époque de Maxwell
Directory of Open Access Journals (Sweden)
René Gallet
2005-01-01
Full Text Available Lorsque l’on veut situer l’œuvre de Hopkins dans son contexte scientifique, on a l’habitude de le faire uniquement par rapport au débat évolutionniste, ou même darwinien, comme dans l’ouvrage de référence de T. Zaniello, Hopkins in the Age of Darwin. Ceci présuppose une vision sélective de ce contexte où figure notamment une autre grande révolution scientifique, dans le domaine de la physique fondamentale. Le représentant le plus éminent en est J. C. Maxwell, chaînon essentiel entre Newton et Einstein. Dans ses textes, Hopkins lui-même s’est intéressé surtout à cette autre révolution scientifique, allant jusqu’à commencer un livre critique envers Light, ouvrage de Tait, physicien de renom et ami de Maxwell. Hopkins s’en prend plus à l’épistémologie idéaliste illustrée, selon le poète, par Tait, qu’à la pensée davantage matérialiste d’un Tyndall. La raison en est sans doute son attachement à un réalisme philosophique dont dépend la notion d’ « inscape ».
Energy Technology Data Exchange (ETDEWEB)
Fochesato, Ch. [CEA Bruyeres-le-Chatel, Dept. de Conception et Simulation des Armes, Service Simulation des Amorces, Lab. Logiciels de Simulation, 91 (France); Bouche, D. [CEA Bruyeres-le-Chatel, Dept. de Physique Theorique et Appliquee, Lab. de Recherche Conventionne, Centre de Mathematiques et Leurs Applications, 91 (France)
2007-07-01
The numerical solution of Maxwell equations is a challenging task. Moreover, the range of applications is very wide: microwave devices, diffraction, to cite a few. As a result, a number of methods have been proposed since the sixties. However, among all these methods, none has proved to be free of drawbacks. The finite difference scheme proposed by Yee in 1966, is well suited for Maxwell equations. However, it only works on cubical mesh. As a result, the boundaries of complex objects are not properly handled by the scheme. When classical nodal finite elements are used, spurious modes appear, which spoil the results of simulations. Edge elements overcome this problem, at the price of rather complex implementation, and computationally intensive simulations. Finite volume methods, either generalizing Yee scheme to a wider class of meshes, or applying to Maxwell equations methods initially used in the field of hyperbolic systems of conservation laws, are also used. Lastly, 'Discontinuous Galerkin' methods, generalizing to arbitrary order of accuracy finite volume methods, have recently been applied to Maxwell equations. In this report, we more specifically focus on the coupling of a Maxwell solver to a PIC (Particle-in-cell) method. We analyze advantages and drawbacks of the most widely used methods: accuracy, robustness, sensitivity to numerical artefacts, efficiency, user judgment. (authors)
Krabbe, A
2000-01-01
The SOFIA telescope as the heart of the observatory is a major technological challenge. I present an overview on the astro-nomical and scientific requirements for such a big airborne observatory and demonstrate the impact of these requirements on the layout of SOFIA, in particular on the telescope design as it is now. Selected components of the telescope will be de-scribed in their context and functionality. The current status of the telescope is presented.
LINEAR GRAVITY WAVES ON MAXWELL FLUIDS OF FINITE DEPTH
Institute of Scientific and Technical Information of China (English)
ZHANG Qinghe; SUN Yabin
2004-01-01
Linear surface gravity waves on Maxwell viscoelastic fluids with finite depth are studied in this paper. A dispersion equation describing the spatial decay of the gravity wave in finite depth is derived. A dimensionless memory (time) number θ is introduced. The dispersion equation for the pure viscous fluid will be a specific case of the dispersion equation for the viscoelastic fluid as θ = 0. The complex dispersion equation is numerically solved to investigate the dispersion relation. The influences of θ and water depth on the dispersion characteristics and wave decay are discussed. It is found that the role of elasticity for the Maxwell fluid is to make the surface gravity wave on the Maxwell fluid behave more like the surface gravity wave on the inviscid fluid.
Generalized Gravitational Entropy of Interacting Scalar Field and Maxwell Field
Huang, Wung-Hong
2014-01-01
The generalized gravitational entropy proposed by Lewkowycz and Maldacena in recent 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 spacetime. The associated modified area law is consistent with the generalized gravitational entropy. Our investigations have not found the unexpected anomalous surface term.
Auto Adjusting Astronomical Telescope
Directory of Open Access Journals (Sweden)
Rohit R. Ghalsasi
2014-04-01
Full Text Available Astronomical telescope is powerful and basic tool for star or celestial observation. Here we proposed integrated system using Raspberry Pi for auto adjusting astronomical telescope. This integrated circuit helps to control stellar monitoring, stellar targeting, and tracking functions of telescope. Astro compass gives the direction of the celestial objects.
Institute of Scientific and Technical Information of China (English)
1995-01-01
Scientists at the Space Telescope Science Institute,which operates the Hubble Space Telescope,have proposed a new telescope that would have twice the resolution of Hubble at about one-tenth the cost. It would hover seven miles above Earth,dangling below a football-field-size helium balloon
ATST telescope mount: telescope of machine tool
Jeffers, Paul; Stolz, Günter; Bonomi, Giovanni; Dreyer, Oliver; Kärcher, Hans
2012-09-01
The Advanced Technology Solar Telescope (ATST) will be the largest solar telescope in the world, and will be able to provide the sharpest views ever taken of the solar surface. The telescope has a 4m aperture primary mirror, however due to the off axis nature of the optical layout, the telescope mount has proportions similar to an 8 meter class telescope. The technology normally used in this class of telescope is well understood in the telescope community and has been successfully implemented in numerous projects. The world of large machine tools has developed in a separate realm with similar levels of performance requirement but different boundary conditions. In addition the competitive nature of private industry has encouraged development and usage of more cost effective solutions both in initial capital cost and thru-life operating cost. Telescope mounts move relatively slowly with requirements for high stability under external environmental influences such as wind buffeting. Large machine tools operate under high speed requirements coupled with high application of force through the machine but with little or no external environmental influences. The benefits of these parallel development paths and the ATST system requirements are being combined in the ATST Telescope Mount Assembly (TMA). The process of balancing the system requirements with new technologies is based on the experience of the ATST project team, Ingersoll Machine Tools who are the main contractor for the TMA and MT Mechatronics who are their design subcontractors. This paper highlights a number of these proven technologies from the commercially driven machine tool world that are being introduced to the TMA design. Also the challenges of integrating and ensuring that the differences in application requirements are accounted for in the design are discussed.
Distribución de probabilidad de Maxwell transmutada
Directory of Open Access Journals (Sweden)
Yuri A Iriarte
2014-01-01
Full Text Available En este artículo introducimos una extensión de la distribución de probabilidad de Maxwell. Esta extensión se genera utilizando el mapa de transmutación de rango cuadrático, estudiado por Shawy Buckleyen[13], considerando como función base la función de distribución acumulada del modelo de Maxwell. Estudiamos propiedades probabilísticas, realizamos inferencia estadística y estudiamos una aplicación con datos reales.
Minimal D=4 supergravity from the superMaxwell algebra
de Azcarraga, J A
2014-01-01
We show that the first-order D=4, N=1 pure supergravity lagrangian four-form can be obtained geometrically as a quadratic expression in the curvatures of the Maxwell superalgebra. This is achieved by noticing that the relative coefficient between the two terms of the Lagrangian that makes the action locally supersymmetric also determines trivial field equations for the gauge fields associated with the extra generators of the Maxwell superalgebra. Along the way, a convenient geometric procedure to check the local supersymmetry of a class of lagrangians is developed.
Minimal D=4 supergravity from the superMaxwell algebra
Energy Technology Data Exchange (ETDEWEB)
Azcárraga, J.A. de [Departamento de Física Teórica and IFIC (CSIC-UVEG), 46100 Burjassot (Valencia) (Spain); Izquierdo, J.M. [Departamento de Física Teórica, Universidad de Valladolid, 47011 Valladolid (Spain)
2014-08-15
We show that the first-order D=4, N=1 pure supergravity lagrangian four-form can be obtained geometrically as a quadratic expression in the curvatures of the Maxwell superalgebra. This is achieved by noticing that the relative coefficient between the two terms of the lagrangian that makes the action locally supersymmetric also determines trivial field equations for the gauge fields associated with the extra generators of the Maxwell superalgebra. Along the way, a convenient geometric procedure to check the local supersymmetry of a class of lagrangians is developed.
The Cherenkov Telescope Array Large Size Telescope
Ambrosi, G; Baba, H; Bamba, A; Barceló, M; de Almeida, U Barres; Barrio, J A; Bigas, O Blanch; Boix, J; Brunetti, L; Carmona, E; Chabanne, E; Chikawa, M; Colin, P; Conteras, J L; Cortina, J; Dazzi, F; Deangelis, A; Deleglise, G; Delgado, C; Díaz, C; Dubois, F; Fiasson, A; Fink, D; Fouque, N; Freixas, L; Fruck, C; Gadola, A; García, R; Gascon, D; Geffroy, N; Giglietto, N; Giordano, F; Grañena, F; Gunji, S; Hagiwara, R; Hamer, N; Hanabata, Y; Hassan, T; Hatanaka, K; Haubold, T; Hayashida, M; Hermel, R; Herranz, D; Hirotani, K; Inoue, S; Inoue, Y; Ioka, K; Jablonski, C; Kagaya, M; Katagiri, H; Kishimoto, T; Kodani, K; Kohri, K; Konno, Y; Koyama, S; Kubo, H; Kushida, J; Lamanna, G; Flour, T Le; López-Moya, M; López, R; Lorenz, E; Majumdar, P; Manalaysay, A; Mariotti, M; Martínez, G; Martínez, M; Mazin, D; Miranda, J M; Mirzoyan, R; Monteiro, I; Moralejo, A; Murase, K; Nagataki, S; Nakajima, D; Nakamori, T; Nishijima, K; Noda, K; Nozato, A; Ohira, Y; Ohishi, M; Ohoka, H; Okumura, A; Orito, R; Panazol, J L; Paneque, D; Paoletti, R; Paredes, J M; Pauletta, G; Podkladkin, S; Prast, J; Rando, R; Reimann, O; Ribó, M; Rosier-Lees, S; Saito, K; Saito, T; Saito, Y; Sakaki, N; Sakonaka, R; Sanuy, A; Sasaki, H; Sawada, M; Scalzotto, V; Schultz, S; Schweizer, T; Shibata, T; Shu, S; Sieiro, J; Stamatescu, V; Steiner, S; Straumann, U; Sugawara, R; Tajima, H; Takami, H; Tanaka, S; Tanaka, M; Tejedor, L A; Terada, Y; Teshima, M; Totani, T; Ueno, H; Umehara, K; Vollhardt, A; Wagner, R; Wetteskind, H; Yamamoto, T; Yamazaki, R; Yoshida, A; Yoshida, T; Yoshikoshi, T
2013-01-01
The two arrays of the Very High Energy gamma-ray observatory Cherenkov Telescope Array (CTA) will include four Large Size Telescopes (LSTs) each with a 23 m diameter dish and 28 m focal distance. These telescopes will enable CTA to achieve a low-energy threshold of 20 GeV, which is critical for important studies in astrophysics, astroparticle physics and cosmology. This work presents the key specifications and performance of the current LST design in the light of the CTA scientific objectives.
Mänd, Anu, 1968-
2008-01-01
Arvustus: Kreem, Juhan. Sketches of a Clerk. Pen-and-ink Drawings in the Margins of the Medieval Accoung Books of Reval (Tallinn). (Krems, 2006). Juhan Kreemi raamat käsitleb Tallinna rae keskaegsetes arveraamatutes leiduvaid sulejoonistusi. Autor on välja selgitanud nende, esmapilgul juhuslikena näivate joonistuste otstarbe ning püüdnud nende kaudu avada tolleaegsete linnaametnike mõttemalle
Liverpool Telescope and Liverpool Telescope 2
Copperwheat, C. M.; Steele, I. A.; Barnsley, R. M.; Bates, S. D.; Clay, N. R.; Jermak, H.; Marchant, J. M.; Mottram, C. J.; Piascik, A.; Smith, R. J.
2016-12-01
The Liverpool Telescope is a fully robotic optical/near-infrared telescope with a 2-metre clear aperture, located at the Observatorio del Roque de los Muchachos on the Canary Island of La Palma. The telescope is owned and operated by Liverpool John Moores University, with financial support from the UK's Science and Technology Facilities Council. The telescope began routine science operations in 2004 and is a common-user facility with time available through a variety of committees via an open, peer reviewed process. Seven simultaneously mounted instruments support a broad science programme, with a focus on transient follow-up and other time domain topics well suited to the characteristics of robotic observing. Development has also begun on a successor facility, with the working title `Liverpool Telescope 2', to capitalise on the new era of time domain astronomy which will be brought about by the next generation of survey facilities such as LSST. The fully robotic Liverpool Telescope 2 will have a 4-metre aperture and an improved response time. In this paper we provide an overview of the current status of both facilities.
Effective Maxwell Equations from Time-dependent Density Functional Theory
Institute of Scientific and Technical Information of China (English)
Weinan E; Jianfeng LU; Xu YANG
2011-01-01
The behavior of interacting electrons in a perfect crystal under macroscopic external electric and magnetic fields is studied. Effective Maxwell equations for the macroscopic electric and magnetic fields are derived starting from time-dependent density functional theory. Effective permittivity and permeability coefficients are obtained.
Introduction to Einstein-Maxwell equations and the Rainich conditions
Santos, Wytler Cordeiro dos
2016-01-01
The first results of Einstein-Maxwell equations established by Raincih in 1925 are therefore called the Raincih conditions. Later the result was rediscovered by Misner and Wheeler in 1957 and made the basis of their geometrodynamics. The present survey will consider didactically the curvature of spacetime attributed to an electromagnetic field with conceptual and calculational details.
Maxwell-Higgs equation on higher dimensional static curved spacetimes
Energy Technology Data Exchange (ETDEWEB)
Mulyanto, E-mail: mulyanto37@gmail.com [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia); Akbar, Fiki Taufik, E-mail: ftakbar@fi.itb.ac.id; Gunara, Bobby Eka, E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung 40132 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP) (Indonesia)
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.
Family of solutions of the Einstein-Maxwell equations
Energy Technology Data Exchange (ETDEWEB)
Gutsunaev, Ts.I.; Manko, V.S.
1988-04-01
A family of axisymmetric asymptotically flat solutions of the Einstein-Maxwell field equations is presented. In a particular case we obtain a magnetostatic solution which reduces to the well-known Schwarzchild metric in the absence of a magnetic field and describes the exterior gravitational field of a massive magnetic dipole moment.
THE ATTRACTORS FOR LANDAU-LIFSHITZ-MAXWELL EQUATIONS
Institute of Scientific and Technical Information of China (English)
Guo Boling; Su Fengqiu
2000-01-01
The existence of the attractors of the periodic initial value problem for the Landau-Lifshitz-Maxwell equations in one and two space dimensions is proved. We also get accurate estimates of the upper bounds of Hausdorff and fractal dimensions for the attractors by means of uniform a priori estimates for time and Lyapunov functional method.
THE GLOBAL SOLUTION FOR LANDAU-LIFSHITZ MAXWELL EQUATIONS
Institute of Scientific and Technical Information of China (English)
Guo Boling; Su Fengqiu
2001-01-01
In this paper, the global existence of a unique smooth solution for the Landau-Lifshitz-Maxwell equations of the ferromagnetic spin chain in n(1≤n≤2) dimensions is established by using a coupled priori estimates in Sobolev spaces.
Maxwell Fields and Shear-Free Null Geodesic Congruences
Newman, E
2004-01-01
We study and report on the class of vacuum Maxwell fields in Minkowski space that possess a non-degenerate, diverging, principle null vector field (null eigenvector field of the Maxwell tensor) that is tangent to a shear-free null geodesics congruence. These congruences can be either surface forming (the tangent vectors proportional to gradients) or not, i.e., the twisting congruences. In the non-twisting case, the associated Maxwell fields are precisely the Lienard-Wiechert fields, i.e., those Maxwell fields arising from an electric monopole moving on an arbitrary worldline. The null geodesic congruence is given by the generators of the light-cones with apex on the world-line. The twisting case is much richer, more interesting and far more complicated. In a twisting subcase, where our main interests lie, it can be given the following strange interpretation. If we allow the real Minkowski space to be complexified so that the real Minkowski coordinates x^a take complex values, i.e., x^a => z^a=x^a+iy^a with co...
Quantum statistical derivation of the macroscopic Maxwell equations
Schram, K.
1960-01-01
The macroscopic Maxwell equations in matter are derived on a quantum statistical basis from the microscopic equations for the field operators. Both the density operator formalism and the Wigner distribution function method are discussed. By both methods it can be proved that the quantum statistical
EXPLORING THE MAXWELL-STEFAN DESCRIPTION OF ION-EXCHANGE
WESSELINGH, JA; VONK, P; KRAAIJEVELD, G
1995-01-01
In ion exchange, water and several ions diffuse simultaneously, with different velocities. They are driven by activity, electrical and pressure gradients. We describe these complicated processes with the Maxwell-Stefan equation. This equation for multicomponent diffusion requires one diffusivity or
Kink shape solutions of the Maxwell-Lorentz system
DEFF Research Database (Denmark)
Sørensen, Mads Peter; Webb, G.M.; Brio, M.
2005-01-01
In the limit of high amplitude oscillating electromagnetic fields, a sequence of kink antikink shaped optical waves has been found in the Maxwell's equations coupled to a single Lorentz oscillator and with Kerr nonlinearity. The individual kinks and antikinks result from a traveling wave assumpti...
Jump Conditions for Maxwell Equations and Their Consequences
2013-01-28
critical issues in computational modeling of electromagnetic systems containing sliding contacts, such as railguns , is the relationship between...an armature is propelled by electromagnetic force. Two stationary conductors (rails) are connected to a capacitor bank. An armature, typically a solid...experimental results. 15. SUBJECT TERMS Maxwell equation, computational electromagnetics , jump condition 16. SECURITY CLASSIFICATION OF: 17
Maxwell-Higgs equation on higher dimensional static curved spacetimes
Mulyanto, Akbar, Fiki Taufik; Gunara, Bobby Eka
2015-09-01
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.
Quasi-Maxwell interpretation of the spin-curvature coupling
Natario, Jose
2007-01-01
We write the Mathisson-Papapetrou equations of motion for a spinning particle in a stationary spacetime using the quasi-Maxwell formalism and give an interpretation of the coupling between spin and curvature. The formalism is then used to compute equilibrium positions for spinning particles in the NUT spacetime.
Quasi-Maxwell interpretation of the spin-curvature coupling
Natário, José
2007-09-01
We write the Mathisson-Papapetrou equations of motion for a spinning particle in a stationary spacetime using the quasi-Maxwell formalism and give an interpretation of the coupling between spin and curvature. The formalism is then used to compute equilibrium positions for spinning particles in the NUT spacetime.
A vielbein formulation of unified Einstein-Maxwell theory
Vignolo, Stefano
2016-01-01
In the framework of J-bundles a vielbein formulation of unified Einstein-Maxwell theory is proposed. In the resulting scheme, field equations matching the gravitational and electromagnetic fields are derived by constraining a five-dimensional variational principle. No dynamical scalar field is involved.
Entanglement entropy of a Maxwell field on the sphere
Casini, Horacio
2015-01-01
We compute the logarithmic coefficient of the entanglement entropy on a sphere for a Maxwell field in $d=4$ dimensions. In spherical coordinates the problem decomposes into one dimensional ones along the radial coordinate for each angular momentum. We show the entanglement entropy of a Maxwell field is equivalent to the one of two identical massless scalars from which the mode of $l=0$ has been removed. This shows the relation $c^M_{\\log}=2 (c^S_{\\log}-c^{S_{l=0}}_{\\log})$ between the logarithmic coefficient in the entropy for a Maxwell field $c^M_{\\log}$, the one for a $d=4$ massless scalar $c_{\\log}^S$, and the logarithmic coefficient $c^{S_{l=0}}_{\\log}$ for a $d=2$ scalar with Dirichlet boundary condition at the origin. Using the accepted values for these coefficients $c_{\\log}^S=-1/90$ and $c^{S_{l=0}}_{\\log}=1/6$ we get $c^M_{\\log}=-16/45$, which coincides with Dowker's calculation, but does not match the coefficient $-\\frac{31}{45}$ in the trace anomaly for a Maxwell field. We have numerically evaluate...
Lattice Boltzmann simulation of transverse wave travelling in Maxwell viscoelastic fluid
Institute of Scientific and Technical Information of China (English)
Li Hua-Bing; Fang Hai-Ping
2004-01-01
A nine-velocity lattice Boltzmann method for Maxwell viscoelastic fluid is proposed. Travelling of transverse wave in Maxwell viscoelastic fluid is simulated. The instantaneous oscillating velocity, transverse shear speed and decay rate agree with theoretical results very well.
How to obtain the covariant form of Maxwell's equations from the continuity equation
Energy Technology Data Exchange (ETDEWEB)
Heras, Jose A [Departamento de Ciencias Basicas, Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa, 02200, Mexico D. F. (Mexico); Departamento de Fisica y Matematicas, Universidad Iberoamericana, Prolongacion Paseo de la Reforma 880, Mexico D. F. 01210 (Mexico)
2009-07-15
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.
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...
JWST Pathfinder Telescope Integration
Matthews, Gary W.; Kennard, Scott H.; Broccolo, Ronald T.; Ellis, James M.; Daly, Elizabeth A.; Hahn, Walter G.; Amon, John N.; Mt. Pleasant, Stephen M.; Texter, Scott; Atkinson, Charles B.; McKay, Andrew; Levi, Joshua; Keski-Kuha, Ritva; Feinberg, Lee
2015-01-01
The James Webb Space Telescope (JWST) is a 6.5m, segmented, IR telescope that will explore the first light of the universe after the big bang. In 2014, a major risk reduction effort related to the Alignment, Integration, and Test (AI&T) of the segmented telescope was completed. The Pathfinder telescope includes two Primary Mirror Segment Assemblies (PMSA's) and the Secondary Mirror Assembly (SMA) onto a flight-like composite telescope backplane. This pathfinder allowed the JWST team to assess the alignment process and to better understand the various error sources that need to be accommodated in the flight build. The successful completion of the Pathfinder Telescope provides a final integration roadmap for the flight operations that will start in August 2015.
Volkmer, R.
2008-09-01
During the last years the new 1.5m solar telescope GREGOR was assembled at Izania on Tenerife, Spain. The telescope is designed for high-precision measurements of the magnetic field in the solar photosphere and chromosphere with a resolution of 70km on the Sun. The telescope concept offers also high resolution stellar spectroscopy. The telescope is build by a consortium of the Kiepenheuer-Institut für Sonnenphysik, the Astrophysikalische Institut Potsdam, the Institut für Astrophysik Göttingen, Max-Plank-Institut für Sonnensystemforschung and additional international Partners. The telescope is a complete open structure with active cooled main mirror. High performance post-focus instruments in the visible and near IR wavelength acquire high resolution spectra with 2 dimensional spatial resolution and polarimetric information. The commissioning of the telescope will start in 2008 to allow first science observations at the end of 2009.
Gillespie, Richard
2011-01-01
Erected at Melbourne Observatory in 1869, the telescope was the second largest in the world, designed to explore the nature of the nebulae in the southern skies. Richard Gillespie, head of the History and Technology department at the Melbourne museum has written an entertaining account of the telescope's extraordinary history and tells the story through an amazing cast of characters whose lives intersected with the telescope.
Wallace, Patrick
2016-07-01
As far as pointing is concerned, a solar telescope is merely an ordinary astronomical telescope but with enhancements for observing solar and coronal features. The paper discusses the additional coordinate systems that need to be supported, shows how to generate the required solar ephemerides (both orbital and physical), and sets out a suitable application programming interface for the telescope control system to use when making solar observations.
Holder, J; Badran, H M; Blaylock, G; Bradbury, S M; Buckley, J H; Byrum, K L; Carter-Lewis, D A; Celik, O; Chow, Y C K; Cogan, P; Cui, W; Daniel, M K; De la Calle-Perez, I; Dowdall, C; Dowkontt, P; Duke, C; Falcone, A D; Fegan, S J; Finley, J P; Fortin, P; Fortson, L F; Gibbs, K; Gillanders, G; Glidewell, O J; Grube, J; Gutíerrez, K J; Gyuk, G; Hall, J; Hanna, D; Hays, E; Horan, D; Hughes, S B; Humensky, T B; Imran, A; Jung, I; Kaaret, Philip; Kenny, G E; Kieda, D; Kildea, J; Knapp, J; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Linton, E; Little, E K; Maier, G; Manseri, H; Milovanovic, A; Moriarty, P; Mukherjee, R; Ogden, P A; Ong, R A; Perkins, J S; Pizlo, F; Pohl, M; Quinn, J; Ragan, K; Reynolds, P T; Roache, E T; Rose, H J; Schroedter, M; Sembroski, G H; Sleege, G A; Steele, D; Swordy, S P; Syson, A; Toner, J A; Valcarcel, L; Vasilev, V V; Wagner, R; Wakely, S P; Weekes, T C; White, R J; Williams, D A
2006-01-01
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications.
LUTE telescope structural design
Ruthven, Gregory
1993-01-01
The major objective of the Lunar Ultraviolet Transit Experiment (LUTE) Telescope Structural Design Study was to investigate the feasibility of designing an ultralightweight 1-m aperture system within optical performance requirements and mass budget constraints. This study uses the results from our previous studies on LUTE as a basis for further developing the LUTE structural architecture. After summarizing our results in Section 2, Section 3 begins with the overall logic we used to determine which telescope 'structural form' should be adopted for further analysis and weight estimates. Specific telescope component analysis showing calculated fundamental frequencies and how they compare with our derived requirements are included. 'First-order' component stress analyses to ensure telescope optical and structural component (i.e. mirrors & main bulkhead) weights are realistic are presented. Layouts of both the primary and tertiary mirrors showing dimensions that are consistent with both our weight and frequency calculations also form part of Section 3. Section 4 presents our calculated values for the predicted thermally induced primary-to-secondary mirror despace motion due to the large temperature range over which LUTE must operate. Two different telescope design approaches (one which utilizes fused quartz metering rods and one which assumes the entire telescope is fabricated from beryllium) are considered in this analysis. We bound the secondary mirror focus mechanism range (in despace) based on these two telescope configurations. In Section 5 we show our overall design of the UVTA (Ultraviolet Telescope Assembly) via an 'exploded view' of the sub-system. The 'exploded view' is annotated to help aid in the understanding of each sub-assembly. We also include a two view layout of the UVTA from which telescope and telescope component dimensions can be measured. We conclude our study with a set of recommendations not only with respect to the LUTE structural architecture
Athermal laser launch telescopes
Kamphues, F.G.; Henselmans, R.; Rijnveld, N.; Lemmen, M.H.J.; Doelman, N.J.; Nijkerk, M.D.
2011-01-01
ESO has developed a concept for a compact laser guide star unit for use in future Adaptive Optics (AO) systems. A small powerful laser is combined with a telescope that launches the beam, creating a single modular unit that can be mounted directly on a large telescope. This approach solves several o
Experimental violation of Tsirelson's bound by Maxwell fields
Sandeau, N.; Akhouayri, H.; Matzkin, A.; Durt, T.
2016-05-01
In analogy with quantum optics it is possible to impose nonseparability between different degrees of freedom of an optical beam. The resulting correlations between these degrees of freedom can be investigated with correlations functions traditionally employed in quantum mechanics, such as the well-known Clauser-Horne-Shimony-Holt (CHSH) correlation function. In this paper we present results achieving a maximal violation of Tsirelson's bound on CHSH correlations between spatial and polarization degrees of freedom of classical (Maxwell) fields. We describe the theoretical method, based on the realization of a nonunitary gate, and then proceed to its experimental implementation carried out with classical optical techniques. Our approach relies on the realization at the level of classical Maxwell fields of a so-called POVM (positive operator valued measure) which is traditionally discussed in the realm of quantum physics.
Reflection-free finite volume Maxwell's solver for adaptive grids
Elkina, Nina
2015-01-01
We present a non-staggered method for the Maxwell equations in adaptively refined grids. The code is based on finite volume central scheme that preserves in a discrete form both divergence-free property of magnetic field and the Gauss law. High spatial accuracy is achieved with help of non-oscillatory extrema preserving piece-wise or piece-wise-quadratic reconstructions. The semi-discrete equations are solved by implicit-explicit Runge-Kutta method. The new adaptive grid Maxwell's solver is examined based on several 1d examples, including the an propagation of a Gaussian pulse through vacuum and partially ionised gas. Two-dimensional extension is tested with a Gaussian pulse incident on dielectric disc. Additionally, we focus on testing computational accuracy and efficiency.
Radiating black holes in Einstein-Maxwell-dilaton theory
Aniceto, Pedro; Rocha, Jorge V
2015-01-01
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 dust 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, we prove that an electrically charged black hole in this theory cannot be overcharged by bombarding it with a stream of electrically charged null dust. This provides an example of cosmic censorship observance in a string theory setting.
Structures of General Relativity in Dilaton-Maxwell Electrodynamics
Kechkin, Oleg V
2016-01-01
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 point-like sourse of the Coulomb type. It is shown that this source is characterized by asymptotical freedom of the electrostatic 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.
Euclidean Maxwell theory in the presence of boundaries
Esposito, G
1995-01-01
This paper describes recent progress in the analysis of relativistic gauge conditions for Euclidean Maxwell theory in the presence of boundaries. The corresponding quantum amplitudes are studied by using Faddeev-Popov formalism and zeta-function regularization, after expanding the electromagnetic potential in harmonics on the boundary 3-geometry. This leads to a semiclassical analysis of quantum amplitudes, involving transverse modes, ghost modes, coupled normal and longitudinal modes, and the decoupled normal mode of Maxwell theory. On imposing magnetic or electric boundary conditions, flat Euclidean space bounded by two concentric 3-spheres is found to give rise to gauge-invariant one-loop amplitudes, at least in the cases considered so far. However, when flat Euclidean 4-space is bounded by only one 3-sphere, one-loop amplitudes are gauge-dependent, and the agreement with the covariant formalism is only achieved on studying the Lorentz gauge. Moreover, the effects of gauge modes and ghost modes do not canc...
Incompressible Einstein–Maxwell fluids with specified electric fields
Indian Academy of Sciences (India)
S Hansraj; S D Maharaj; T Mthethwa
2013-10-01
The Einstein–Maxwell equations describing static charged spheres with uniform density and variable electric field intensity are studied. The special case of constant electric field is also studied. The evolution of the model is governed by a hypergeometric differential equation which has a general solution in terms of special functions. Several classes of exact solutions are identified which may be considered as charged generalizations of the incompressible Schwarzschild interior model. An analysis of the physical features is undertaken for the uniform case. It is demonstrated that uniform density spheres with constant electric field intensity are not realizable with isotropic pressures. This highlights the necessity of studying the criteria for physical admissability of gravitating spheres in general relativity which are solutions to the Einstein–Maxwell equations.
Notes on Stefan-Maxwell Equation versus Grahan's Diffusion Law
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
Certain prerequisite information on the component fluxes is necessary for solution of the Stefan-Maxwell equation in multicomponent diffusion systems and the Graham's law of diffusion and effusion is often resorted for this purpose. This article addresses solution of the Stefan-Maxwell equation in binary gas systems and explores the necessary conditions for definite solution of concentration profiles and pertinent component fluxes. It is found that there are multiple solutions for component fluxes in contradiction to what specified by the Graham's law of diffusion. The theorem of minimum entropy production in the non-equilibrium thermodynamics is believed instructive in determining the stable steady state solution out of infinite multiple solutions possible under the specified conditions. It is suggested that only when the boundary condition of component concentration is symmetrical in an isothermal binary system, the counter-diffusion becomes equimolar. The Graham's law of diffusion seems not generally valid for the case of isothermal ordinary diffusion.
The global formulation of generalized Einstein-Scalar-Maxwell theories
Lazaroiu, C
2016-01-01
We summarize the global geometric formulation of Einstein-Scalar-Maxwell theories twisted by flat symplectic vector bundle which encodes the duality structure of the theory. We describe the scalar-electromagnetic symmetry group of such models, which consists of flat unbased symplectic automorphisms of the flat symplectic vector bundle lifting those isometries of the scalar manifold which preserve the scalar potential. The Dirac quantization condition for such models involves a local system of integral symplectic spaces, giving rise to a bundle of polarized Abelian varieties equipped with a symplectic flat connection, which is defined over the scalar manifold of the theory. Generalized Einstein-Scalar-Maxwell models arise as the bosonic sector of the effective theory of string/M-theory compactifications to four-dimensions, and they are characterized by having non-trivial solutions of "U-fold" type.
The JCMT Plane Survey: early results from the ℓ = 30° field
Moore, T. J. T.; Plume, R.; Thompson, M. A.; Parsons, H.; Urquhart, J. S.; Eden, D. J.; Dempsey, J. T.; Morgan, L. K.; Thomas, H. S.; Buckle, J.; Brunt, C. M.; Butner, H.; Carretero, D.; Chrysostomou, A.; deVilliers, H. M.; Fich, M.; Hoare, M. G.; Manser, G.; Mottram, J. C.; Natario, C.; Olguin, F.; Peretto, N.; Polychroni, D.; Redman, R. O.; Rigby, A. J.; Salji, C.; Summers, L. J.; Berry, D.; Currie, M. J.; Jenness, T.; Pestalozzi, M.; Traficante, A.; Bastien, P.; diFrancesco, J.; Davis, C. J.; Evans, A.; Friberg, P.; Fuller, G. A.; Gibb, A. G.; Gibson, S.; Hill, T.; Johnstone, D.; Joncas, G.; Longmore, S. N.; Lumsden, S. L.; Martin, P. G.; Lu'o'ng, Q. Nguyê˜n.; Pineda, J. E.; Purcell, C.; Richer, J. S.; Schieven, G. H.; Shipman, R.; Spaans, M.; Taylor, A. R.; Viti, S.; Weferling, B.; White, G. J.; Zhu, M.
2015-01-01
We present early results from the JCMT (James Clerk Maxwell Telescope) Plane Survey (JPS), which has surveyed the northern inner Galactic plane between longitudes ℓ = 7° and ℓ = 63° in the 850-μm continuum with SCUBA-2 (Submm Common-User Bolometer Array 2), as part of the JCMT Legacy Survey programm
SENSITIVE LIMITS ON THE MOLECULAR GAS CONTENT OF CLUSTER COOLING FLOWS
MCNAMARA, BR; JAFFE, W
1994-01-01
We have searched for molecular gas toward six cluster cooling flows in the CO(2-1) line using the James Clerk Maxwell Telescope. The sample includes clusters with estimated total cooling rates Of m(CF) approximately 10-600M. yr-1, at redshifts between z approximately 0.01-0.06. None were detected ei
Flexible Software for Flexible Scheduling
Economou, Frossie; Jenness, Tim; Tilanus, Remo P. J.; Hirst, Paul; Adamson, Andy J.; Rippa, Mathew; Delorey, Kynan K.; Isaak, Kate G.
The JAC Observation Management Project (OMP) provides software for the James Clerk Maxwell (JCMT) and the United Kingdom Infrared (UKIRT) telescopes that manages the life-cycle of flexibly scheduled observations. Its aim is to increase observatory efficiency under flexible (queue) scheduled observing, without depriving the principal investigator (PI) of the flexibility associated with classical scheduling.
An Unbiased Survey of 500 Nearby Stars for Debris Disks: A JCMT Legacy Program
Matthews, B.C.; Greaves, J.S.; Holland, W.S.; Wyatt, M.C.; Barlow, M.J.; Bastien, P.; Beichman, C.A.; Biggs, A.; Butner, H.M.; Dent, W.R.F.; Di Francesco, J.; Dominik, C.; Fissel, L.; Friberg, P.; Gibb, A.G.; Halpern, M.; Ivison, R.J.; Jayawardhana, R.; Jenness, T.; Johnstone, D.; Kavelaars, J.J.; Marshall, J.L.; Phillips, N.; Schieven, G.; Snellen, I.A.G.; Walker, H.J.; Ward-Thompson, D.; Weferling, B.; White, G.J.; Yates, J.; Zhu, M.; Craigon, A.
2007-01-01
We present the scientific motivation and observing plan for an upcoming detection survey for debris disks using the James Clerk Maxwell Telescope. The SCUBA-2 Unbiased Nearby Stars (SUNS) survey will observe 500 nearby main-sequence and subgiant stars (100 of each of the A, F, G, K, and M spectral c
An Unbiased Survey of 500 Nearby Stars for Debris Disks : A JCMT Legacy Program
Matthews, B.C.; Greaves, J.S.; Holland, W.S.; Wyatt, M.C.; Barlow, M.J.; Bastien, P.; Beichman, C.A.; Biggs, A.; Butner, H.M.; Dent, W.R.F.; Francesco, J. Di; Dominik, C.; Fissel, L.; Friberg, P.; Gibb, A.G.; Halpern, M.; Ivison, R.J.; Jayawardhana, R.; Jenness, T.; Johnstone, D.; Kavelaars, J.J.; Marshall, J.L.; Phillips, N.; Schieven, G.; Snellen, I.A.G.; Walker, H.J.; Ward-Thompson, D.; Weferling, B.; White, G.J.; Yates, J.; Zhu, M.
2007-01-01
We present the scientific motivation and observing plan for an upcoming detection survey for debris disks using the James Clerk Maxwell Telescope. The SCUBA-2 Unbiased Nearby Stars (SUNS) survey will observe 500 nearby main-sequence and subgiant stars (100 of each of the A, F, G, K, and M spectral c
Wilson, C. D.; Warren, B. E.; Israel, F. P.; Serjeant, S.; Attewell, D.; Bendo, G. J.; Butner, H. M.; Chanial, P.; Clements, D. L.; Golding, J.; Heesen, V.; Irwin, J.; Leech, J.; Matthews, H. E.; Mühle, S.; Mortier, A. M. J.; Petitpas, G.; Sánchez-Gallego, J. R.; Sinukoff, E.; Shorten, K.; Tan, B. K.; Tilanus, R. P. J.; Usero, A.; Vaccari, M.; Wiegert, T.; Zhu, M.; Alexander, D. M.; Alexander, P.; Azimlu, M.; Barmby, P.; Brar, R.; Bridge, C.; Brinks, E.; Brooks, S.; Coppin, K.; Côté, S.; Côté, P.; Courteau, S.; Davies, J.; Eales, S.; Fich, M.; Hudson, M.; Hughes, D. H.; Ivison, R. J.; Knapen, J. H.; Page, M.; Parkin, T. J.; Rigopoulou, D.; Rosolowsky, E.; Seaquist, E. R.; Spekkens, K.; Tanvir, N.; van der Hulst, J. M.; van der Werf, P.; Vlahakis, C.; Webb, T. M.; Weferling, B.; White, G. J.
2012-01-01
The James Clerk Maxwell Telescope Nearby Galaxies Legacy Survey (NGLS) comprises an H I-selected sample of 155 galaxies spanning all morphological types with distances less than 25 Mpc. We describe the scientific goals of the survey, the sample selection and the observing strategy. We also present a
Infinitesimal Carnot cycle and Maxwell's first relation
Energy Technology Data Exchange (ETDEWEB)
Menon, V J [Department of Physics, Banaras Hindu University, Varanasi 221 005 (India); Agrawal, D C [Department of Farm Engineering, Banaras Hindu University, Varanasi 221 005 (India)
2006-11-01
We demonstrate that by employing usual calculus along with the first law, the efficiency of a Carnot cycle can be evaluated when the working substance has an arbitrary equation of state. This leads to a neat derivation of Maxwell's first relation without using either the properties of perfect differentials as done by Tjiang and Sutanto or the abstract symbolism of topology as done by Hannay.
Derivation of special relativity from Maxwell and Newton.
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.
Algorithm development for Maxwell's equations for computational electromagnetism
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.
Comment on 'Perfect drain for the Maxwell fish eye lens'
Sun, Fei
2012-01-01
The non-magnetic loss material has been proposed (2011 New J. Phys. 13 023038) to mimic a passive perfect drain in the Maxwell's fish eye lens (MFL). In this comment, we argue that this passive medium can only be treated as a perfect absorber which can totally absorb all incident radiation without scattering by it, but it cannot mimic a delta function at the image point. As a result, this passive medium cannot help to achieve a perfect focusing in MFL.
A Re-Examination of Maxwell's Electrodynamics Equations
Directory of Open Access Journals (Sweden)
Dunning-Davies J.
2015-10-01
Full Text Available It is pointed out that the usual derivation of the well-known Maxwell electromagnetic equations holds only for a medium at rest. A way in which the equations may be modified for the case when the mean flow of the medium is steady and uniform is proposed. The implication of this for the problem of the origin of planetary magnetic fields is discussed.
Introducing polarization and magnetization into Maxwell's equations: A modified approach
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.
Asymptotic stability of the Boltzmann equation with Maxwell boundary conditions
Briant, Marc; Guo, Yan
2016-12-01
In a general C1 domain, we study the perturbative Cauchy theory for the Boltzmann equation with Maxwell boundary conditions with an accommodation coefficient α in (√{ 2 / 3 } , 1 ], and discuss this threshold. We consider polynomial or stretched exponential weights m (v) and prove existence, uniqueness and exponential trend to equilibrium around a global Maxwellian in Lx,v∞ (m). Of important note is the fact that the methods do not involve contradiction arguments.
Class of Einstein-Maxwell-Dilaton-Axion Space-Times
2009-01-01
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 $Sp(4,\\Rreal)\\sim O(5)$. 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 generalise the Schwarzschild solution with dilaton, axion and electromagnetic fields.
Thermodynamics of a physical model implementing a Maxwell demon
Strasberg, Philipp; Schaller, Gernot; Brandes, Tobias; Esposito, Massimiliano
2012-01-01
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 contributi...
How an autonomous quantum Maxwell demon can harness correlated information
Chapman, Adrian; Miyake, Akimasa
2015-01-01
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...
A Modified Szilard's Engine: Measurement, Information, and Maxwell's Demon
Michael Devereux
2004-01-01
Abstract: 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 ...
The Hamiltonian Structure of the Maxwell-Vlasov Equations.
1981-02-01
principle of Percival [1979). 4. By using an appropriate Darboux theorem, (see Marsden [1981], lecture 1), one can show that Of admits canonically...get the Vlasov-Poisson equation. It would also be of interest to realize both the Vlasov-Maxwell and MHD equations as limiting cases of a grand...de Vries equation, Springer Lecture Notes, #755, 1-15 and Inv. Math. 50, 219-248. J. Arms (1979]. Linearization stability of gravitational and gauge
Environmental Assessment: Military Family Housing Privatization Maxwell Air Force Base
2005-06-01
Laws that are applicable. Sincerely, d~~ Tim Thompson Cultural Advisor (918) 732-7732 x7732 Received Feb-28-2005 OJ :53pm From-334 953 5151 To...Street Montgomery. Atabama 36130-0900 tel 334 242•3184 fax 334 240• 3477 www. , .: .org September 27, 2004 Deborah K. Tharp Command Cultural...2004-1360 NR Eligibility WWII Barracks/Maxwell & Gunter Montgomery County Dear Ms. Tharp : The Alabama Historical Commission agrees that the above
Maxwell boundary conditions imply non-Lindblad master equation
Bamba, Motoaki; Imoto, Nobuyuki
2016-09-01
From the Hamiltonian connecting the inside and outside of a Fabry-Pérot cavity, which is derived from the Maxwell boundary conditions at a mirror of the cavity, a master equation of a non-Lindblad form is derived when the cavity embeds matters, although we can transform it to the Lindblad form by performing the rotating-wave approximation to the connecting Hamiltonian. We calculate absorption spectra by these Lindblad and non-Lindblad master equations and also by the Maxwell boundary conditions in the framework of the classical electrodynamics, which we consider the most reliable approach. We found that, compared to the Lindblad master equation, the absorption spectra by the non-Lindblad one agree better with those by the Maxwell boundary conditions. Although the discrepancy is highlighted only in the ultrastrong light-matter interaction regime with a relatively large broadening, the master equation of the non-Lindblad form is preferable rather than of the Lindblad one for pursuing the consistency with the classical electrodynamics.
Holography and hydrodynamics for EMD theory with two Maxwell fields
Smolic, Milena
2013-01-01
We use `generalized dimensional reduction' to relate a specific Einstein-Maxwell-Dilaton (EMD) theory, including two gauge fields, three neutral scalars and an axion, to higher-dimensional AdS gravity (with no higher-dimensional Maxwell field). In general, this is a dimensional reduction over compact Einstein spaces in which the dimension of the compact space is continued to non-integral values. Specifically, we perform a non-diagonal Kaluza-Klein (KK) reduction over a torus, involving two KK gauge fields. Our aim is to determine the holographic dictionary and hydrodynamic behaviour of the lower-dimensional theory by performing the generalized dimensional reduction on AdS. We study a specific example of a black brane carrying a wave, whose universal sector is described by gravity coupled to two Maxwell fields, three neutral scalars and an axion, and compute the first order transport coefficients of the dual theory. In these theories $\\hat{\\z}_s / \\hat{\\eta} < 2(1(d-1)-\\hat{c}_s^2)$, where $\\hat{c}_s$ is th...
On subwavelength imaging with Maxwell's fish eye lens
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a subwavelength image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point imaging for a single object point is also demonstrated.
On subwavelength imaging of Maxwell's fish eye lens
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens, which has been claimed recently to be able to achieve perfect imaging. We show that such a Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in the Maxwell's fish eye. If only zero order mode is excited, a subwavelength image can be achieved, however, its spot-size is larger than the spot size of the source field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a modified fish eye bounded with perfectly electrical conductor (PEC). Explicit condition is given for achieving a subwavelength image. When this condition is not satisfied, a single line current source may give multiple image spots.
Can Maxwell's fish eye lens really give perfect imaging?
Sun, Fei
2010-01-01
Both explicit analysis and FEM numerical simulation are used to analyze the field distribution of a line current in the so-called Maxwell's fish eye lens [bounded with a perfectly electrical conductor (PEC) boundary]. We show that such a 2D Maxwell's fish eye lens cannot give perfect imaging due to the fact that high order modes of the object field can hardly reach the image point in Maxwell's fish eye lens. If only zeroth order mode is excited, a good image of a sharp object may be achieved in some cases, however, its spot-size is larger than the spot size of the initial object field. The image resolution is determined by the field spot size of the image corresponding to the zeroth order component of the object field. Our explicit analysis consists very well with the FEM results for a fish eye lens. Time-domain simulation is also given to verify our conclusion. Multi-point images for a single object point are also demonstrated.
Noncommutative Geometry Framework and The Feynman's Proof of Maxwell Equations
Boulahoual, A
2003-01-01
The main focus of the present work is to study the Feynman's proof of the Maxwell equations using the NC geometry framework. To accomplish this task, we consider two kinds of noncommutativity formulations going along the same lines as Feynman's approach. This allows us to go beyond the standard case and discover non-trivial results. In fact, while the first formulation gives rise to the static Maxwell equations, the second formulation is based on the following assumption $m[x_{j},\\dot{x_{k}}]=i\\hbar \\delta_{jk}+im\\theta_{jk}f.$ The results extracted from the second formulation are more significant since they are associated to a non trivial $\\theta $-extension of the Bianchi-set of Maxwell equations. We find $div_{\\theta}B=\\eta_{\\theta}$ and $\\frac{\\partial B_{s}}{\\partial t}+\\epsilon_{kjs}\\frac{\\partial E_{j}}{\\partial x_{k}}=A_{1}\\frac{d^{2}f}{dt^{2}}+A_{2}\\frac{df}{dt}+A_{3},$ where $\\eta_{\\theta}$, $A_{1}$, $A_{2}$ and $A_{3}$ are local functions depending on the NC $\\theta $-parameter. The novelty of this...
Maxwell boundary conditions impose non-Lindblad master equation
Bamba, Motoaki
2016-01-01
From the Hamiltonian connecting the inside and outside of an Fabry-Perot cavity, which is derived from the Maxwell boundary conditions at a mirror of the cavity, a master equation of a non-Lindblad form is derived when the cavity embeds matters, although we can transform it to the Lindblad form by performing the rotating-wave approximation to that Hamiltonian. We calculate absorption spectra by these Lindblad and non-Lindblad master equations and also by the Maxwell boundary conditions in framework of the classical electrodynamics, which we consider the most reliable approach. We found that, compared to the Lindblad master equation, the absorption spectra by the non-Lindblad one agree better with those by the Maxwell boundary conditions. Although the discrepancy is highlighted only in the ultra-strong light-matter interaction regime with a relatively large broadening, the master equation of the non-Lindblad form is preferable rather than of the Lindblad one for pursuing the consistency with the classical elec...
Energy Technology Data Exchange (ETDEWEB)
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.
Two Easily Made Astronomical Telescopes.
Hill, M.; Jacobs, D. J.
1991-01-01
The directions and diagrams for making a reflecting telescope and a refracting telescope are presented. These telescopes can be made by students out of plumbing parts and easily obtainable, inexpensive, optical components. (KR)
Directory of Open Access Journals (Sweden)
Kirby John R
2005-10-01
Full Text Available Abstract Background In a study to determine the site and preceptor characteristics most valued by clerks and residents in the ambulatory setting we wished to confirm whether these would support effective learning. The deep approach to learning is thought to be more effective for learning than surface approaches. In this study we determined how the approaches to learning of clerks and residents predicted the valued site and preceptor characteristics in the ambulatory setting. Methods Postal survey of all medical residents and clerks in training in Ontario determining the site and preceptor characteristics most valued in the ambulatory setting. Participants also completed the Workplace Learning questionnaire that includes 3 approaches to learning scales and 3 workplace climate scales. Multiple regression analysis was used to predict the preferred site and preceptor characteristics as the dependent variables by the average scores of the approaches to learning and perception of workplace climate scales as the independent variables. Results There were 1642 respondents, yielding a 47.3% response rate. Factor analysis revealed 7 preceptor characteristics and 6 site characteristics valued in the ambulatory setting. The Deep approach to learning scale predicted all of the learners' preferred preceptor characteristics (β = 0.076 to β = 0.234, p Direction was more strongly associated with the Surface Rational approach (β = .252, p Surface Disorganized approach to learning (β = .154, p Deep approach. The Deep approach to learning scale predicted valued site characteristics of Office Management, Patient Logistics, Objectives and Preceptor Interaction (p Surface Rational approach to learning predicted valuing Learning Resources and Clinic Set-up (β = .09, p = .001; β = .197, p Surface Disorganized approach to learning weakly negatively predicted Patient Logistics (β = -.082, p = .003 and positively the Learning Resources (β = .088, p = .003. Climate
Wolsky, Alan M
2014-01-01
Though sufficient for local conservation of charge, Maxwells displacement current is not necessary. An alternative to the Ampere-Maxwell equation is exhibited and the alternatives electric and magnetic fields and scalar and vector potentials are expressed in terms of the charge and current densities. The magnetic field is shown to satisfy the Biot_Savart Law. The electric field is shown to be the sum of the gradient of a scalar potential and the time derivative of a vector potential which is different from but just as tractable as the simplest vector potential that yields the Biot_Savart Law The alternative describes a theory in which action is instantaneous and so may provide a good approximation to Maxwells equations where and when the finite speed of light can be neglected. The result recalls the Darwin approximation which arose from the study classical charged point particles to order (v/c)2 in the Lagrangian. Unlike Darwin, this approach does not depend on the constitution of the electric current. Instea...
Modular assembled space telescope
Feinberg, Lee D.; Budinoff, Jason; MacEwen, Howard; Matthews, Gary; Postman, Marc
2013-09-01
We present a new approach to building a modular segmented space telescope that greatly leverages the heritage of the Hubble Space Telescope and the James Webb Space Telescope. The modular design in which mirror segments are assembled into identical panels allows for economies of scale and for efficient space assembly that make a 20-m aperture approach cost effective. This assembly approach can leverage NASA's future capabilities and has the power to excite the public's imagination. We discuss the science drivers, basic architecture, technology, and leveraged NASA infrastructure, concluding with a proposed plan for going forward.
Goddard Robotic Telescope (GRT)
National Aeronautics and Space Administration — Since it is not possible to predict when a Gamma-Ray Burst (GRB) occurs, the follow-up ground telescopes must be distributed as uniform as possible all over the...
Chadzitaskos, Goce
2013-01-01
We present a proposal of a new type of telescopes using a rotating parabolic strip as the primary mirror. It is the most principal modification of the design of telescopes from the times of Galileo and Newton. In order to demonstrate the basic idea, the image of an artificial constellation observed by this kind of telescope was reconstructed using the techniques described in this article. As a working model of this new telescope, we have used an assembly of the primary mirror---a strip of acrylic glass parabolic mirror 40 cm long and 10 cm wid shaped as a parabolic cylinder of focal length 1 m---and an artificial constellation, a set of 5 apertures in a distance of 5 m illuminated from behind. In order to reconstruct the image, we made a series of snaps, each after a rotation of the constellation by 15 degrees. Using Matlab we reconstructed the image of the artificial constellation.
Tyson, J A; Angel, J R P; Wittman, David
2001-01-01
Weak gravitational lensing enables direct reconstruction of dark matter maps over cosmologically significant volumes. This research is currently telescope-limited. The Dark Matter Telescope (DMT) is a proposed 8.4 m telescope with a 3 degree field of view, with an etendue of 260 $(m. degree)^2$, ten times greater than any other current or planned telescope. With its large etendue and dedicated observational mode, the DMT fills a nearly unexplored region of parameter space and enables projects that would take decades on current facilities. The DMT will be able to reach 10-sigma limiting magnitudes of 27-28 magnitude in the wavelength range .3 - 1 um over a 7 square degree field in 3 nights of dark time. Here we review its unique weak lensing cosmology capabilities and the design that enables those capabilities.
Large Binocular Telescope Project
Hill, John M.
1997-03-01
The large binocular telescope (LBT) project have evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 by 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson, Arizona. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train -- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in the fall of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximum flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximum stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1996 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson), EIE and ADS Italia
Twinlike models for self-dual Maxwell-Higgs theories
Energy Technology Data Exchange (ETDEWEB)
Bazeia, D.; Hora, E. da [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Dept. de Fisica; Menezes, R. [Universidade Federal da Paraiba (UFPB), Rio Tinto, PB (Brazil). Dept. de Ciencias Exatas
2012-07-01
Full text: We present the development of a coherent first-order theoretical framework that allows for the existence of twinlike models in the context of a generalized self-dual Maxwell-Higgs theories. Here, the generalized model is controlled by two dimensionless functions, h (|{phi}|) and w (|{phi}|) , which are functions of the Higgs field only. Furthermore, these functions are assumed to be positive, in order to avoid problems with the energy of the overall model. In this context, for a given constraint between h (|{phi}|), w (|{phi}|) and the symmetry breaking Higgs potential V (|{phi}|), we found BPS equations by minimizing the generalized total energy. Here, even in the presence of non-trivial choices to h (|{phi}|), w (|{phi}|) and V (|{phi}|), the resulting equations mimic the standard first-order ones. Therefore, given the usual finite-energy boundary conditions, the generalized model engenders the very same topologically non-trivial configurations as the standard Maxwell-Higgs theory. The energy of such configurations is bounded from below, this bound being equal to the magnetic flux, which is quantized according the winding number, as expected. Even in this case, it is important to note that the generalized model is not a parametrization of the usual Maxwell-Higgs one. We study the resulting BPS configurations via the canonical radially symmetric Ansatz, and we found electrically non-charged time-independent vortex solutions which engender the very same magnetic field. In this sense, since this field is related to the topological stability of the usual vortex configurations, we believe the stability of the generalized model can be achieve in the same way. We use a combination of theoretical and numerical techniques to show that different choices to h (|{phi}|) and w (|{phi}|) engender different energy densities, even in the presence of the very same field solutions. In this case, we show that all these densities give the very same total energy. (author)
Traffic restrictions on Routes Bloch, Maxwell and Bohr
TS Department
2008-01-01
Excavation and pipework is being carried out in the framework of the transfer of the waste water treatment plant for the effluents from the surface treatment workshops from Building 254 to Building 676, currently under construction. This work may encroach onto Routes Bloch, Maxwell and Bohr and disrupt the flow of traffic. Users are requested to comply with the road signs that will be erected. The work is expected to last until the beginning of December 2008. Thank you for your understanding. TS/CE and TS/FM Groups Tel.7 4188 or 16 4314
Second order guiding-center Vlasov–Maxwell equations
DEFF Research Database (Denmark)
Madsen, Jens
2010-01-01
including second order terms. The second order contributions contain the lowest order finite-Larmor-radius corrections to the electromagnetic field. Therefore, the model is capable of describing situations where strong E×B-flows and finite-Larmor-radius effects are mutually important.......Second order gyrogauge invariant guiding-center coordinates with strong E×B-flow are derived using the Lie transformation method. The corresponding Poisson bracket structure and equations of motion are obtained. From a variational principle the explicit Vlasov–Maxwell equations are derived...
INITIAL VALUE TECHNIQUES FOR THE HELMHOLTZ AND MAXWELL EQUATIONS
Institute of Scientific and Technical Information of China (English)
Frank Natterer; Olga Klyubina
2007-01-01
We study the initial value problem of the Helmholtz equation with spatially variable wave number. We show that it can be stabilized by suppressing the evanescent waves. The stabilized Helmholtz equation can be solved numerically by a marching scheme combined with FFT. The resulting algorithm has complexity n2 log n on a n x n grid. We demonstrate the efficacy of the method by numerical examples with caustics. For the Maxwell equation the same treatment is possible after reducing it to a second order system. We show how the method can be used for inverse problems arising in acoustic tomography and microwave imaging.
GLOBAL SOLVABILITY FOR A NONLINEAR SEMI-STATIC MAXWELL'S EQUATION
Institute of Scientific and Technical Information of China (English)
Yin Hongming; Lu Guofu
2006-01-01
In this paper we study a nonlinear Maxwell's system in a highly conductive medium in which the displacement current is neglected. The magnetic field H satisfies a quasilinear evolution system: Ht + ▽ × [r(x, t, |H|, |▽ × H|)▽ × H] = F(x, t, H),where the resistivity r is assumed to depend upon the strengths of electric and magnetic fields while the internal magnetic current F depends upon the magnetic field. It is shown that under appropriate structure conditions for r and F the above nonlinear system subject to appropriate initial-boundary conditions has a unique global solution.
Light wave propagation through a dilaton-Maxwell domain wall
Morris, J R
2015-01-01
We consider the propagation of electromagnetic waves through a dilaton-Maxwell domain wall of the type introduced by Gibbons and Wells [G.W. Gibbons and C.G. Wells, Class. Quant. Grav. 11, 2499-2506 (1994)]. It is found that if such a wall exists within our observable universe, it would be absurdly thick, or else have a magnetic field in its core which is much stronger than observed intergalactic fields. We conclude that it is highly improbable that any such wall is physically realized.
BPS Solutions to a Generalized Maxwell-Higgs Model
Bazeia, D.(Departamento de Física, Universidade Federal da Paraíba, João Pessoa, PB, 58051-970, Brazil); da Hora, E.; Santos, C. dos(Centro de Física e Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, 4169-007, Porto, Portugal); Menezes, R.(Departamento de Física, Universidade Federal de Campina Grande, 58109-970 Campina Grande, PB, Brazil)
2012-01-01
We look for topological BPS solutions of an Abelian-Maxwell-Higgs theory endowed by non-standard kinetic terms to both gauge and scalar fields. Here, the non-usual dynamics are controlled by two positive functions, G(|{\\phi}|) and w(|{\\phi}|), which are related to the self-dual scalar potential V(|{\\phi}|) of the model by a fundamental constraint. The numerical results we found present interesting new features, and contribute to the development of the recent issue concerning the study of gene...
SIM(1)-VSR Maxwell-Chern-Simons electrodynamics
Bufalo, R.
2016-06-01
In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM (1)-VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and healthy departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges is derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.
SIM$(1)$--VSR Maxwell-Chern-Simons electrodynamics
Bufalo, R
2016-01-01
In this paper we propose a very special relativity (VSR)-inspired generalization of the Maxwell-Chern-Simons (MCS) electrodynamics. This proposal is based upon the construction of a proper study of the SIM$(1)$--VSR gauge-symmetry. It is shown that the VSR nonlocal effects present a significant and health departure from the usual MCS theory. The classical dynamics is analysed in full detail, by studying the solution for the electric field and static energy for this configuration. Afterwards, the interaction energy between opposite charges are derived and we show that the VSR effects play an important part in obtaining a (novel) finite expression for the static potential.
Quantum criticality in Einstein-Maxwell-dilaton gravity
Energy Technology Data Exchange (ETDEWEB)
Wen, Wen-Yu, E-mail: steve.wen@gmail.com [California Institute of Technology, Pasadena, CA 91125 (United States); Department of Physics and Center for Theoretical Sciences and Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 106, Taiwan (China); Department of Physics, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)
2012-02-01
We investigate the quantum Lifshitz criticality in a general background of Einstein-Maxwell-dilaton gravity. In particular, we demonstrate the existence of critical point with dynamic critical exponent z by tuning a nonminimal coupling to its critical value. We also study the effect of nonminimal coupling and exponent z to the Efimov states and holographic RG flow in the overcritical region. We have found that the nonminimal coupling increases the instability for a probe scalar to condensate and its back reaction is discussed. At last, we give a quantum mechanics treatment to a solvable system with z=2, and comment for generic z>2.
Viscoelastic Modelling of Solid Rocket Propellants using Maxwell Fluid Model
Directory of Open Access Journals (Sweden)
Himanshu Shekhar
2010-07-01
Full Text Available Maxwell fluid model consisting of a spring and a dashpot in series is applied for viscoelastic characterisation of solid rocket propellants. Suitable values of spring constant and damping coefficient wereemployed by least square variation of errors for generation of complete stress-strain curve in uniaxial tensile mode for case-bonded solid propellant formulations. Propellants from the same lot were tested at different strain rates. It was observed that change in spring constant, representing elastic part was very small with strain rate but damping constant varies significantly with variation in strain rate. For a typical propellant formulation, when strain rate was raised from 0.00037/s to 0.185/s, spring constant K changed from 5.5 MPato 7.9 MPa, but damping coefficient D was reduced from 1400 MPa-s to 4 MPa-s. For all strain rates, stress-strain curve was generated using Maxwell model and close matching with actual test curve was observed.This indicates validity of Maxwell fluid model for uniaxial tensile testing curves of case-bonded solid propellant formulations. It was established that at higher strain rate, damping coefficient becomes negligible as compared to spring constant. It was also observed that variation of spring constant is logarithmic with strain rate and that of damping coefficient follows power law. The correlation coefficients were introduced to ascertain spring constants and damping coefficients at any strain rate from that at a reference strain rate. Correlationfor spring constant needs a coefficient H, which is function of propellant formulation alone and not of test conditions and the equation developeds K2 = K1 + H ´ ln{(de2/dt/(de1/dt}. Similarly for damping coefficient D also another constant S is introduced and prediction formula is given by D2 = D1 ´ {(de2/dt/(de1/dt}S.Evaluating constants H and S at different strain rates validate this mathematical formulation for differentpropellant formulations
Climate Controlled Sedimentation in Maxwell Bay, King George Island, Antarctica
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
How an autonomous quantum Maxwell demon can harness correlated information
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.
NON SPURIOUS SPECTRAL-LIKE ELEMENT METHODS FOR MAXWELL'S EQUATIONS
Institute of Scientific and Technical Information of China (English)
Gary Cohen; Marc Duruflé
2007-01-01
In this paper, we give the state of the art for the so called "mixed spectral elements" for Maxwell's equations. Several families of elements, such as edge elements and discontinuous Galerkin methods (DGM) are presented and discussed. In particular, we show the need of introducing some numerical dissipation terms to avoid spurious modes in these methods. Such terms are classical for DGM but their use for edge element methods is a novel approach described in this paper. Finally, numerical experiments show the fast and low-cost character of these elements.
DEVELOPMENT OF A NEW BRIDGE OF MAXWELL-WIEN
2001-01-01
Nos Institutos Nacionais de Metrologia para a medição da grandeza de indutância com alta exatidão usam-se circuitos especiais, desenvolvidos e montados pelos próprios laboratórios. Esta dissertação de mestrado descreve o desenvolvimento e a realização de uma nova construção da ponte de Maxwell-Wien, usada para a padronização e disseminação da unidade henry do Instituto Nacional de Metrologia, Normalização e Qualidade Industrial - INMETRO. Na parte teórica do tra...
Carleton, Nathaniel P.; Hoffmann, William F.
1978-01-01
Describes the basic design and principle of operating an optical-infrared telescope, the MMT. This third largest telescope in the world represents a new stage in telescope design; it uses a cluster of six reflecting telescopes, and relies on an automatic sensing and control system. (GA)
Energy Technology Data Exchange (ETDEWEB)
Piechotowski, I.; Jaroni, J. [Landesgesundheitsamt Baden-Wuerttemberg, Stuttgart (Germany); Link, B. [Arbeits- und Sozialministerium des Landes Baden-Wuerttemberg, Stuttgart (Germany); Groezinger, O. [Ministerium fuer Umwelt und Verkehr des Landes Baden-Wuerttemberg, Stuttgart (Germany)
2000-07-01
In 47 forest clerks from the regions Ortenau and Oberschwaben in south-west Germany the incorporation of cesium 137 and potassium 40 was measured in autumn 1994. Soil burden as well as burden of nutrition with cesium 137 are different in these regions for geological reasons and as a result of the nuclear accident of Chernobyl. Caused by low content of clay in Oberschwaben, the transfer of cesium to plants is assisted. Heavy rainfall after the nuclear accident led to an additional increase of burden. The median of the concentration of cesium 137 was 1.4 Bq/kg body weight. The median for potassium 40 was 58 Bq/kg body weight. For cesium 137 regional differences were observed. For persons from Oberschwaben the median for cesium 137 was with 2.8 Bq/kg body weight clearly higher than for persons from Ortenau with 0,6 Bq/kg body weight. Concerning nutrition habits, the clearest difference was found comparing persons who had ate a minimum of four portions of deer from the surroundings within the last four weeks with persons who had ate less than four portions of deer from the surroundings within the last four weeks. The difference was greater in Oberschwaben than in Ortenau. The effective dose of cesium 137 calculated on the basis of the incorporation is very low compared to natural radiation. This is also valid for persons from Oberschwaben. (orig.) [German] Im Herbst 1994 wurde bei insgesamt 47 Bediensteten der Forstverwaltung aus den Regionen Ortenaukreis und Oberschwaben die Inkorportation an Caesium 137 und Kalium 40 gemessen. Sowohl die Bodenbelastung als auch die Belastung von Nahrungsmitteln mit Caesium 137 unterscheiden sich in diesen Gebieten bedingt durch geologische Besonderheiten und in Folge des Reaktorunfalls von Tschernobyl. Aufgrund eines geringen Anteils an Tonerden wird in Oberschwaben der Caesiumtransfer in Pflanzen beguenstigt, eine zusaetzliche Erhoehung der Belastung erfolgte durch starke Niederschlaege nach dem Reaktorunfall. Die Konzentration fuer
Directory of Open Access Journals (Sweden)
Roman Leischik
Full Text Available This study examined the association between the physical work environment and physiological performance measures, physical activity levels and metabolic parameters among German civil servants. A main focus in this study was to examine the group differences rather than measuring the absolute values in an occupational group.We prospectively examined 198 male German civil servants (97 firefighters [FFs], 55 police officers [POs] and 46 sedentary clerks [SCs]. For each parameter, the groups were compared using a linear regression adjusted for age.The 97 FFs showed a similar maximal aerobic power (VO2max l/min of 3.17±0.44 l/min compared with the POs, who had a maximal aerobic power of 3.13±0.62 l/min (estimated difference, POs vs. FFs: 0.05, CI: -0.12-0.23, p=0.553. The maximal aerobic power of the FFs was slightly higher than that of the SCs, who had a maximal aerobic power of 2.85±0.52 l/min (-0.21, CI: -0.39-0.04, p=0.018 vs. FFs. The average physical activity (in metabolic equivalents [METS]/week of the FFs was 3953±2688, whereas those of the POs was 2838±2872 (vs. FFs: -985, CI: -1941-30, p = 0.043 and of the SCs 2212±2293 (vs. FFs: -1598.8, CI: -2477-721, p = 0.000; vs. POs: -613.6, CI: -1617.4–390.3, p = 0.229, respectively [corrected]. For the FFs, the average body fat percentage was 17.7%±6.2, whereas it was 21.4%±5.6 for the POs (vs. FFs: 2.75, CI: 0.92-4.59, p=0.004 and 20.8%±6.5 for the SCs (vs. FFs: 1.98, CI: -0.28-4.25, p=0.086; vs. POs: -0.77, CI: 3.15-1.61, p=0.523. The average waist circumference was 89.8 cm±10.0 for the FFs, 97.8 cm±12.4 (5.63, CI: 2.10-9.15, p=0.002 for the POs, and 97.3±11.7 (vs. FFs: -4.89, CI: 1.24-8.55, p=0.009; vs. POs: -0.73, CI: -5.21-3.74, p=0.747 for the SCs.The FFs showed significantly higher physical activity levels compared with the SCs. The PO group had the highest cardiovascular risk of all of the groups because it included more participants with metabolic syndrome; furthermore, the POs
Ruhl, J E; Carlstrom, J E; Cho, H M; Crawford, T; Dobbs, M; Greer, C H; Halverson, W; Holzapfel, W L; Lanting, T M; Lee, A T; Leong, J; Leitch, E M; Lu, W; Lueker, M; Mehl, J; Meyer, S S; Mohr, J J; Padin, S; Plagge, T; Pryke, C L; Schwan, D; Sharp, M K; Runyan, M C; Spieler, H; Staniszewski, Z; Stark, A A
2004-01-01
A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency...
Woźniak, Przemysław
Robotic telescopes are revolutionizing the way astronomers collect their dataand conduct sky surveys. This chapter begins with a discussion of principles thatguide the process of designing, constructing, and operating telescopes andobservatories that offer a varying degree of automation, from instruments remotelycontrolled by observers to fully autonomous systems requiring no humansupervision during their normal operations. Emphasis is placed on designtrade-offs involved in building end-to-end systems intended for a wide range ofscience applications. The second part of the chapter contains descriptions ofseveral projects and instruments, both existing and currently under development.It is an attempt to provide a representative selection of actual systems thatillustrates state of the art in technology, as well as important ideas and milestonesin the development of the field. The list of presented instruments spans the fullrange in size starting from small all-sky monitors, through midrange robotic andsurvey telescopes, and finishing with large robotic instruments and surveys.Explosive growth of telescope networking is enabling entirely new modesof interaction between the survey and follow-up observing. Increasingimportance of standardized communication protocols and software is stressed.These developments are driven by the fusion of robotic telescope hardware,massive storage and databases, real-time knowledge extraction, and datacross-correlation on a global scale. The chapter concludes with examplesof major science results enabled by these new technologies and futureprospects.
Murabona Oduori, Susan
2015-08-01
The telescope has been around for more than 400 years, and through good use of it scientists have made many astonishing discoveries and begun to understand our place in the universe. Most people, however, have never looked through one. Yet it is a great tool for cool science and observation especially in a continent and country with beautifully dark skies. The Travelling Telescope project aims to invite people outside under the stars to learn about those curious lights in the sky.The Travelling Telescope aims to promote science learning to a wide range of Kenyan schools in various locations exchanging knowledge about the sky through direct observations of celestial bodies using state of the art telescopes. In addition to direct observing we also teach science using various hands-on activities and astronomy software, ideal for explaining concepts which are hard to understand, and for a better grasp of the sights visible through the telescope. We are dedicated to promoting science using astronomy especially in schools, targeting children from as young as 3 years to the youth, teachers, their parents and members of the public. Our presentation focuses on the OAD funded project in rural coastal Kenya.
Energy Technology Data Exchange (ETDEWEB)
Ruhl, J.E.; Ade, P.A.R.; Carlstrom, J.E.; Cho, H.M.; Crawford,T.; Dobbs, M.; Greer, C.H.; Halverson, N.W.; Holzapfel, W.L.; Lanting,T.M.; Lee, A.T.; Leitch, E.M.; Leong, J.; Lu, W.; Lueker, M.; Mehl, J.; Meyer, S.S.; Mohr, J.J.; Padin, S.; Plagge, T.; Pryke, C.; Runyan, M.C.; Schwan, D.; Sharp, M.K.; Spieler, H.; Staniszewski, Z.; Stark, A.A.
2004-11-04
A new 10 meter diameter telescope is being constructed for deployment at the NSF South Pole research station. The telescope is designed for conducting large-area millimeter and sub-millimeter wave surveys of faint, low contrast emission, as required to map primary and secondary anisotropies in the cosmic microwave background. To achieve the required sensitivity and resolution, the telescope design employs an off-axis primary with a 10 m diameter clear aperture. The full aperture and the associated optics will have a combined surface accuracy of better than 20 microns rms to allow precision operation in the submillimeter atmospheric windows. The telescope will be surrounded with a large reflecting ground screen to reduce sensitivity to thermal emission from the ground and local interference. The optics of the telescope will support a square degree field of view at 2mm wavelength and will feed a new 1000-element micro-lithographed planar bolometric array with superconducting transition-edge sensors and frequency-multiplexed readouts. The first key project will be to conduct a survey over 4000 degrees for galaxy clusters using the Sunyaev-Zeldovich Effect. This survey should find many thousands of clusters with a mass selection criteria that is remarkably uniform with redshift. Armed with redshifts obtained from optical and infrared follow-up observations, it is expected that the survey will enable significant constraints to be placed on the equation of state of the dark energy.
A Maxwell elasto-brittle rheology for sea ice modelling
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.
Einstein-aether theory with a Maxwell field: General formalism
Energy Technology Data Exchange (ETDEWEB)
Balakin, Alexander B., E-mail: Alexander.Balakin@kpfu.ru [Department of General Relativity and Gravitation, Institute of Physics, Kazan Federal University, Kremlevskaya str. 18, Kazan 420008 (Russian Federation); Lemos, José P.S., E-mail: joselemos@ist.utl.pt [Centro Multidisciplinar de Astrofísica-CENTRA, Departamento de Física, Instituto Superior Técnico-IST, Universidade de Lisboa-UL, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)
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.
LSST telescope modeling overview
Sebag, J.; Andrew, J.; Angeli, G.; Araujo, C.; Barr, J.; Callahan, S.; Cho, M.; Claver, C.; Daruich, F.; Gressler, W.; Hileman, E.; Liang, M.; Muller, G.; Neill, D.; Schoening, W.; Warner, M.; Wiecha, O.; Xin, B.; Orden Martinez, Alfredo; Perezagua Aguado, Manuel; García Marchena, Luis; Ruiz de Argandoña, Ismael
2016-08-01
During this early stage of construction of the Large Synoptic Survey Telescope (LSST), modeling has become a crucial system engineering process to ensure that the final detailed design of all the sub-systems that compose the telescope meet requirements and interfaces. Modeling includes multiple tools and types of analyses that are performed to address specific technical issues. Three-dimensional (3D) Computeraided Design (CAD) modeling has become central for controlling interfaces between subsystems and identifying potential interferences. The LSST Telescope dynamic requirements are challenging because of the nature of the LSST survey which requires a high cadence of rapid slews and short settling times. The combination of finite element methods (FEM), coupled with control system dynamic analysis, provides a method to validate these specifications. An overview of these modeling activities is reported in this paper including specific cases that illustrate its impact.
Kitchin, C R
2013-01-01
Telescopes and Techniques has proved itself in its first two editions, having become probably one of the most widely used astronomy texts, both for amateur astronomers and astronomy and astrophysics undergraduates. Both earlier editions of the book were widely used for introductory practical astronomy courses in many universities. In this Third Edition the author guides the reader through the mathematics, physics and practical techniques needed to use today's telescopes (from the smaller models to the larger instruments installed in many colleges) and how to find objects in the sky. Most of the physics and engineering involved is described fully and requires little prior knowledge or experience. Both visual and electronic imaging techniques are covered, together with an introduction to how data (measurements) should be processed and analyzed. A simple introduction to radio telescopes is also included. Brief coverage of the more advanced topics of photometry and spectroscopy are included, but mainly to enable ...
Wilson, Raymond N
2004-01-01
R.N. Wilson's two-volume treatise on reflecting telescope optics has become a classic in its own right. It is intended to give a complete treatment of the subject, addressing professionals in research and industry as well as students of astronomy and amateur astronomers. This first volume, Basic Design Theory and its Historical Development, is devoted to the theory of reflecting telescope optics and systematically recounts the historical progress. The author's approach is morphological, with strong emphasis on the historical development. The book is richly illustrated including spot-diagrams a
Institute of Scientific and Technical Information of China (English)
2011-01-01
With its pure aperture up to 985mm, the New Vacuum Solar Telescope of China （NVST） has become the world＇s biggest vacuum solar telescope. The main science task of NVST is the high-resolution observation of photosphere and chromosphere including their fine structure of magnetic field on the sun. The NVST was equipped with many new technologies and powerful instruments, such as an adaptive optical system, a polarization analyzer, two vertical spectrographs, a high-resolution image system and a very narrow Ha filter （0.125A）.
Gross, Michael A K; Moore, Elizabeth M
2010-01-01
SOFIA is an airborne, gyroscopically stabilized 2.5m infrared telescope, mounted to a spherical bearing. Unlike its predecessors, SOFIA will work in absolute coordinates, despite its continually changing position and attitude. In order to manage this, SOFIA must relate equatorial and telescope coordinates using a combination of avionics data and star identification, manage field rotation and track sky images. We describe the algorithms and systems required to acquire and maintain the equatorial reference frame, relate it to tracking imagers and the science instrument, set up the oscillating secondary mirror, and aggregate pointings into relocatable nods and dithers.
Comments on Dirac-like monopole, Maxwell and Maxwell-Chern-Simons electrodynamics in D=(2+1)
Energy Technology Data Exchange (ETDEWEB)
Moura-Melo, Winder A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: winder@cbpf.br; Helayel Neto, J.A. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica. E-mail: helayel@cbpf.br
2000-05-01
Classical Maxwell and Maxwell-Chern-Simons Electrodynamics in (2+1) D are studied in some details. General expressions for the potential and fields are obtained for both models, and some particular cases are explicitly solved. Conceptual and technical difficulties arise, however, for accelerated charges. The propagation of electromagnetic signals is also studied and their reverberation is worked out and discussed. Furthermore, we show that a Dirac-like monopole yields a (static) tangential electric field. We also discuss some classical and quantum consequences of the field created by such a monopole when acting upon an usual electric charge. In particular, we show that at large distances, the dynamics of one single charged particle under the action of such a potential and a constant (external) magnetic field as well, reduces to that of one central harmonic oscillator, presenting, however, an interesting angular sector which admits energy-eigenvalues. For example, the quantisation of these eigenvalues yields a Dirac-like condition on the product of the charges. Moreover, such eigenvalues are shown to feel (and respond) to discrete shift of the angle variable. We also raise the question on the possibility of the formation pf bound states in this system. (author)
To Flame With a Wild Life: Florida Scott-Maxwell's Experience of Old Age.
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)
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...
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...
Infinite Maxwell fish-eye lens as a complement for an imaging device
Liu, Yangjie; Naeem, Majid; Hao, Yang
2015-01-01
This manuscript proposes a new imaging medium via isotropic refractive index of heterogeneous medium. By aid of conformal map, one transfers the full Maxwell fisheye into a mapped profile within a unit circle. Thus the imaging resolution of this new profile is maintained as good as the truncated Maxwell fisheye profile or its conformally-mapped counterpart in previous literature.
Straulino, S.; Bonechi, L.
2010-01-01
Two lenses make it possible to create a simple telescope with quite large magnification. The set-up is very simple and can be reproduced in schools, provided the laboratory has a range of lenses with different focal lengths. In this article, the authors adopt the Keplerian configuration, which is composed of two converging lenses. This instrument,…
Straulino, Samuele; Terzuoli, Alessandra
2010-01-01
In the first months of 2009, the International Year of Astronomy, the authors developed an educational project for middle-level students connected with the first astronomical discoveries that Galileo Galilei (1564-1642) made 400 years ago. The project included the construction of a basic telescope and the observation of the Moon. The project, if…
THE LARGE MILLIMETER TELESCOPE
Directory of Open Access Journals (Sweden)
D. H. Hughes
2009-01-01
Full Text Available This paper, presented on behalf of the Large Millimeter Telescope (LMT project team, describes the status and near-term plans for the telescope and its initial instrumentation. The LMT is a bi-national collaboration between M xico and the USA, led by the Instituto Nacional de Astrof sica, ptica y Electr nica (INAOE and the University of Massachusetts at Amherst, to construct, commission and operate a 50 m diameter millimeterwave radio telescope. Construction activities are nearly complete at the LMT site, at an altitude of 4600 m on the summit of Sierra Negra, an extinct volcano in the Mexican state of Puebla. Full movement of the telescope, under computer control in both azimuth and elevation, has been achieved. First-light at centimeter wavelengths on astronomical sources was obtained in November 2006. Installation of precision surface segments for millimeter-wave operation is underway, with the inner 32 m diameter of the surface now complete and ready to be used to obtain rst-light at millimeter wavelengths in 2008. Installation of the remainder of the re ector will continue during the next year and be completed in 2009 for nal commissioning of the antenna. The full LMT antenna, out ted with its initial complement of scienti c instruments, will be a world-leading scienti c research facility for millimeter-wave astronomy.
Slightly generalized Maxwell classical electrodynamics can be applied to inneratomic phenomena
Simulik, V M
2002-01-01
In order to extend the limits of classical theory application in the microworld some weak generalization of Maxwell electrodynamics is suggested. It is shown that slightly generalized classical Maxwell electrodynamics can describe the intraatomic phenomena with the same success as relativistic quantum mechanics can do. Group-theoretical grounds for the description of fermionic states by bosonic system are presented briefly. The advantages of generalized electrodynamics in intraatomic region in comparison with standard Maxwell electrodynamics are demonstrated on testing example of hydrogen atom. We are able to obtain some results which are impossible in the framework of standard Maxwell electrodynamics. The Sommerfeld - Dirac formula for the fine structure of the hydrogen atom spectrum is obtained on the basis of such Maxwell equations without appealing to the Dirac equation. The Bohr postulates and the Lamb shift are proved to be the consequences of the equations under consideration. The relationship of the n...
Chaotic Dynamics of Falling Disks: from Maxwell to Bar Tricks.
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 nori/disks/pub.html>bar wagering strategies. Recent theoretical studies have emphasized the role played by deterministic chaos. Here we nori/falling.html>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.
Maxwell's enduring legacy a scientific history of the Cavendish laboratory
Longair, Malcolm
2016-01-01
The Cavendish Laboratory is arguably the most famous physics laboratory in the world. Founded in 1874, it rapidly gained a leading international reputation through the researches of the Cavendish professors beginning with Maxwell, Rayleigh, J. J. Thomson, Rutherford and Bragg. Its name will always be associated with the discoveries of the electron, the neutron, the structure of the DNA molecule and pulsars, but these are simply the tip of the iceberg of outstanding science. The physics carried out in the laboratory is the central theme of the book and this is explained in reasonably non-technical terms. The research activities are set in their international context. Generously illustrated, with many pictures of the apparatus used and diagrams from the original papers, the story is brought right up to date with descriptions of the science carried out under the leadership of the very different personalities of Mott, Pippard and Edwards.
The road to Maxwell's demon conceptual foundations of statistical mechanics
Hemmo, Meir
2012-01-01
Time asymmetric phenomena are successfully predicted by statistical mechanics. Yet the foundations of this theory are surprisingly shaky. Its explanation for the ease of mixing milk with coffee is incomplete, and even implies that un-mixing them should be just as easy. In this book the authors develop a new conceptual foundation for statistical mechanics that addresses this difficulty. Explaining the notions of macrostates, probability, measurement, memory, and the arrow of time in statistical mechanics, they reach the startling conclusion that Maxwell's Demon, the famous perpetuum mobile, is consistent with the fundamental physical laws. Mathematical treatments are avoided where possible, and instead the authors use novel diagrams to illustrate the text. This is a fascinating book for graduate students and researchers interested in the foundations and philosophy of physics.
Foxboro, Bradley gear combined at Maxwell House plant
Energy Technology Data Exchange (ETDEWEB)
Maggs, J.
1986-02-03
In what is described as an unusual installation, industrial process control equipment from the Foxboro Co., Foxboro, Mass., and Allen Bradley Co., Milwaukee, was combined at General Foods' Maxwell House plant in Houston, and is working together with a Hewlett-Packard 1000 computer to improve product quality and cut energy costs, according to Kevin McCormick, decaffeination business manager. As a result, the process controls are expected to reduce energy costs at the facility by 5 to 10%, he said. Four Foxboro model 300 systems were installed to provide monitoring and analog control of four processes - coffee bean decaffeination, instant coffee preparation, Minute Rice preparation, and separate Foxboro system to control the plant's two boilers, which are fired with natural gas and with waste coffee grounds.
Structures of general relativity in dilaton-Maxwell electrodynamics
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.
Cubic interactions of Maxwell-like higher spins
Francia, Dario; Mkrtchyan, Karapet
2016-01-01
We study the cubic vertices for Maxwell-like higher-spins in flat space. Reducibility of their free spectra implies that a single cubic vertex involving any three fields subsumes a number of couplings among different particles of various spins. The resulting vertices do not involve traces of the fields and in this sense are simpler than their Fronsdal counterparts. We propose an extension of both the free theory and of its cubic deformation to a more general class of partially reducible systems, that one can obtain from the original theory upon imposing trace constraints of various orders. The key to our results is a version of the Noether procedure allowing to systematically account for the deformations of the transversality conditions to be imposed on the gauge parameters at the free level.
Holographic Renormalization of Einstein-Maxwell-Dilaton Theories
Kim, Bom Soo
2016-01-01
We generalize the boundary value problem with a mixed boundary condition that involves the gauge and scalar fields in the context of Einstein-Maxwell-Dilaton theories. In particular, the expectation value of the dual scalar operator can be a function of the expectation value of the current operator. The properties are prevalent in a fixed charge ensemble because the conserved charge is shared by both fields through the dilaton coupling, which is also responsible for non-Fermi liquid properties. We study the on-shell action and the stress energy tensor to note practical importances of the boundary value problem. In the presence of the scalar fields, physical quantities are not fully fixed due to the finite boundary terms that manifest in the massless scalar or the scalar with mass saturating the Breitenlohner-Freedman bound.
Einstein-Maxwell equations for asymmetric resonant cavities
Frasca, Marco
2015-01-01
We analyze the behavior of electromagnetic fields inside a resonant cavity by solving Einstein--Maxwell field equations. It is shown that the modified geometry of space-time inside the cavity due to a propagating mode can affect the propagation of a laser beam. It is seen that components of laser light with a shifted frequency appear originating from the coupling between the laser field and the mode cavity due to gravity. The analysis is extended to the case of an asymmetric resonant cavity taken to be a truncated cone. It is shown that a proper choice of the geometrical parameters of the cavity and dielectric can make the gravitational effects significant for an interferometric setup. This could make possible to realize table-top experiments involving gravitational effects.
A Generalization of the Einstein-Maxwell Equations
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
Perfect drain for the Maxwell Fish Eye lens
Gonzalez, Juan C; Minano, Juan C
2010-01-01
Perfect imaging for electromagnetic waves using the Maxwell Fish Eye (MFE) requires a new concept: the perfect drain. From the mathematical point of view, a perfect point drain is just like an ideal point source, except that it drains power from the electromagnetic field instead of generating it. We show here that the perfect drain for the MFE can be seen as a dissipative region the diameter of which tends to zero. The complex permittivity $\\varepsilon$ of this region cannot take arbitrary values, however, since it depends on the size of the drain as well as on the frequency. This interpretation of the perfect drain connects well with central concepts of electromagnetic theory. This opens up both the modeling in computer simulations and the experimental verification of the perfect drain.
Hydrodynamic Burnett equations for inelastic Maxwell models of granular gases
Khalil, Nagi; Garzó, Vicente; Santos, Andrés
2014-05-01
The hydrodynamic Burnett equations and the associated transport coefficients are exactly evaluated for generalized inelastic Maxwell models. In those models, the one-particle distribution function obeys the inelastic Boltzmann equation, with a velocity-independent collision rate proportional to the γ power of the temperature. The pressure tensor and the heat flux are obtained to second order in the spatial gradients of the hydrodynamic fields with explicit expressions for all the Burnett transport coefficients as functions of γ, the coefficient of normal restitution, and the dimensionality of the system. Some transport coefficients that are related in a simple way in the elastic limit become decoupled in the inelastic case. As a byproduct, existing results in the literature for three-dimensional elastic systems are recovered, and a generalization to any dimension of the system is given. The structure of the present results is used to estimate the Burnett coefficients for inelastic hard spheres.
Dynamics of multilayered orthotropic viscoelastic plates of Maxwell solids
Directory of Open Access Journals (Sweden)
P. Pal Roy
1988-01-01
Full Text Available This paper is concerned with a simplified dynamical analysis of orthotropic viscoelastic plates that are made up of an arbitrary number of layers each of which is a Maxwell type solid. This study includes the case where some or all the layers are themselves constituted by thinly laminated materials with couple stresses. The recurrence equations for the shear stresses are obtained for an arbitrary number of layers and then applied to plates with two or three layers. The viscoelastic damping effect is determined by the process of linearization and then illustrated by a plate composed of one, two or three layers. It is found that the damping increases with anisotropy and wave number. These results are shown by graphical representations.
Aquaporin-1 is a Maxwell's Demon in the Body
Shu, Liangsuo; Xiaokang,; Qian, Liu Xin; Huang, Suyi; Jin, Shiping; Yang, Baoxue
2015-01-01
Aquaporin-1 (AQP1) is a membrane protein which is selectively permeable to water. Due to its hourglass shape, AQP1 can sense the information of solute molecules in osmosis. At the cost of consuming this information, AQP1 can move water against its chemical potential gradient: it works as one kind of Maxwell's Demon. This effect was detected quantitatively by measuring the water osmosis of mice erythrocytes. This ability may protect the erythrocytes from the eryptosis elicited by osmotic shock when they move in the kidney, where a large gradient of urea is required for the urine concentrating mechanism. This finding anticipates a new beginning of inquiries into the complicated relationships among mass, energy and information in bio-systems.
Holographic Fermions in Anisotropic Einstein-Maxwell-Dilaton-Axion Theory
Directory of Open Access Journals (Sweden)
Li-Qing Fang
2015-01-01
Full Text Available We investigate the properties of the holographic Fermionic system dual to an anisotropic charged black brane bulk in Einstein-Maxwell-Dilaton-Axion gravity theory. We consider the minimal coupling between the Dirac field and the gauge field in the bulk gravity theory and mainly explore the dispersion relation exponents of the Green functions of the dual Fermionic operators in the dual field theory. We find that along both the anisotropic and the isotropic directions the Fermi momentum will be effected by the anisotropy of the bulk theory. However, the anisotropy has influence on the dispersion relation which is almost linear for massless Fermions with charge q=2. The universal properties that the mass and the charge of the Fermi possibly correspond to nonlinear dispersion relation are also investigated.
Big-Bang Nucleosynthesis verifies classical Maxwell-Boltzmann distribution
Hou, S Q; Parikh, A; Daid, K; Bertulani, C
2014-01-01
We provide the most stringent constraint to date on possible deviations from the usually-assumed Maxwell-Boltzmann (MB) velocity distribution for nuclei in the Big-Bang plasma. The impact of non-extensive Tsallis statistics on thermonuclear reaction rates involved in standard models of Big-Bang Nucleosynthesis (BBN) has been investigated. We find that the non-extensive parameter $q$ may deviate by, at most, $|\\delta q|$=6$\\times$10$^{-4}$ from unity for BBN predictions to be consistent with observed primordial abundances; $q$=1 represents the classical Boltzmann-Gibbs statistics. This constraint arises primarily from the {\\em super}sensitivity of endothermic rates on the value of $q$, which is found for the first time. As such, the implications of non-extensive statistics in other astrophysical environments should be explored. This may offer new insight into the nucleosynthesis of heavy elements.
Perfect drain for the Maxwell fish eye lens
González, Juan C.; Benítez, Pablo; Miñano, Juan C.
2011-02-01
Perfect imaging of electromagnetic waves using the Maxwell fish eye (MFE) requires a new concept: a point called the perfect drain that we shall call the perfect point drain. From the mathematical point of view, a perfect point drain is just like an ideal point source, except that it drains power from the electromagnetic field instead of generating it. We introduce here the perfect drain for the MFE as a dissipative region of non-zero size that completely drains the power from the point source. To accomplish this goal, the region must have a precise complex permittivity that depends on its size as well as on the frequency. The perfect point drain is obtained when the diameter of the perfect drain tends to zero. This interpretation of the perfect point drain is connected well with common concepts of electromagnetic theory, opening up both modeling in computer simulations and experimental verification of setups containing a perfect point drain.
How can an autonomous quantum Maxwell demon harness correlated information?
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.
Quantum Entanglement of Locally Excited States in Maxwell Theory
Nozaki, Masahiro
2016-01-01
In 4 dimensional Maxwell gauge theory, we study the changes of (Renyi) entangle-ment entropy which are defined by subtracting the entropy for the ground state from the one for the locally excited states generated by acting with the 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.
Geometric Model of Topological Insulators from the Maxwell Algebra
Palumbo, Giandomenico
2016-01-01
We propose a novel geometric model of three-dimensional topological insulators in presence of an external electromagnetic field. The gapped boundary of these systems supports relativistic quantum Hall states and is described by a Chern-Simons theory with a gauge connection that takes values in the Maxwell algebra. This represents a non-central extension of the Poincar\\'e algebra and takes into account both the Lorentz and magnetic-translation symmetries of the surface states. In this way, we derive a relativistic version of the Wen-Zee term, and we show that the non-minimal coupling between the background geometry and the electromagnetic field in the model is in agreement with the main properties of the relativistic quantum Hall states in the flat space.
Deciphering the embedded wave in Saturn's Maxwell ringlet
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
Multidimensional Cosmology with a Generalized Maxwell Field Integrable Cases
Bronnikov, K A
1997-01-01
We consider multidimensional cosmologies in even-dimensional space-times (D=2n) containg perfect fluid and a multidimensional generalization of the Maxwell field, preserving its conformal invariance (the F field, an n-form). Among models with an isotropic physical 3-space some integrable cases are found: vacuum models (which are integrable in the general case) and some perfect fluid models with barotropic equations of state. All of them contain a component of the F field appearing as an additional scalar in 4 dimensions. A two-parameter family of spatially flat models and four one-parameter families, including non-spatially flat models, have been obtained (where the parameters are constants from the fluid equation of state). All these integrable models admit the inclusion of a massless scalar field or an additional fluid with ultrastiff equation of state. Basic properties of vacuum models in the physical conformal frame are outlined.
On the stationary Einstein-Maxwell field equations
Das, A.; Kloster, S.
1980-08-01
The stationary gravitational equations in the presence of the electromagnetic fields, outside charged gravitating sources, are investigated. (i) The action integral of Kramer-Neugebauer-Stephani (K.N.S.) is derived from the Hilbert action integral by using new variational techniques. (ii) It is shown that the classification scheme for the system of partial differential equations of general relativity depends on the coordinate system used. In particular, if orthogonal coordinates are chosen for the associated space then the system of Einstein-Maxwell equations is a hyperbolic one. (iii) The eigenvalues of the Ricci tensor of associated space are expressed in terms of the invariants of stationary electro-gravitational fields. It is proved that if these eigenvalues are equal then the fields must belong to the class of Peres-Israel-Wilson (PIW) solutions. (iv) The global integrability of some of the stationary Einstein-Maxwell equations and the consequent equilibrium conditions of the ''bodies'' are investigated. (v) Boundary value problems for some of the field equations are pursued. It is proved that ω≡ln||g44|| is neither subharmonic nor superharmonic and the boundary value problem for this function does not yield a unique solution in general. A nontrivial solution of the stationary equations with ω≡0 is given. A special boundary value problem is explicitly solved. (vi) The PIW solutions are generated from the charged Kerr-Tomimatsu-Sato-Yamazaki (KTSY) solutions. The complex axially symmetric harmonic functions of these PIW solutions can be obtained from the real axially symmetric harmonic functions of the static Weyl class of electrovac solutions by a complex scale transformation of the coordinates.
Optical Space Telescope Assembly Project
National Aeronautics and Space Administration — The Optical Space Telescope Assembly (OSTA) task is to demonstrate the technology readiness of assembling large space telescopes on orbit in 2015. This task is an...
NRAO Green Bank Telescope (GBT)
Federal Laboratory Consortium — The largest fully steerable telescope in the world - the Robert C. Byrd Green Bank Telescope, began observations in Green Bank, West Virginia in 2000and is a wonder...
Uzaybimer Radio Telescope Control System
Balbay, R.; Öz, G. K.; Arslan, Ö.; Özeren, F. F.; Küçük, İ.
2016-12-01
A 13 meters former NATO radar is being converted into a radio telescope. The radio telescope is controlled by a system which has been developed at UZAYBİMER. The Telescope Control System(TCS) has been designed using modern industrial systems. TCS has been developed in LabView platform in which works Windows embedded OS. The position feedback used on radio telescopes is an industrial EtherCAT standard. ASCOM library is used for astronomical calculations.
Progress in Space Solar Telescope
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
In this paper we will summarize the progress in the development of the Chinese Space Solar Telescope (SST) during the past few years. The main scientific objective of SST is to observe the fundamental structure of solar magnetic field with its 1-m optical telescope. The success of 1-m Swedish Solar Telescope and Hinode underscores the importance of this 1-m space telescope. In addition, some key technical problems have been solved.
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...
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...
The ANTARES Neutrino Telescope
Perrina, Chiara
2015-01-01
At about 40 km off the coast of Toulon (France), anchored at 2475 m deep in the Mediterranean Sea, there is ANTARES: the first undersea neutrino telescope and the only one currently operating. The detector consists of 885 photomultiplier tubes arranged into 12 strings of 450-metres high, with the aim to detect the Cherenkov light induced by the charged superluminal interaction products of neutrinos. Its main scientific target is the search for high-energy (TeV and beyond) neutrinos from cosmic accelerators, as predicted by hadronic interaction models, and the measurement of the cosmic neutrino diffuse flux, focusing in particular on events coming from below the horizon (up-going events) in order to significantly reduce the atmospheric muons background. Thanks to the development of a strategy for the identification of neutrinos coming from above the horizon (down-going events) the field of view of the telescope will be extended.
Telescopic limiting magnitudes
Schaefer, Bradley E.
1990-01-01
The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.
Greco, V; Molesini, G; Quercioli, F
1993-11-01
The Florentine Istituto e Museo di Storia delta Scienza houses two complete telescopes and a single objective lens (reconstructed from several fragments) that can be attributed to Galileo. These optics have been partially dismantled and made available for optical testing with state-of-the-art equipment. The lenses were investigated individually; the focal length and the radii of curvature were measured, and the optical layout of the instruments was worked out. The optical quality of the surfaces and the overall performance of the two complete telescopes have been evaluated interferometrically at a wavelength of 633 nm (with a He-Ne laser source). It was found in particular that the optics of Galileo came close to attaining diffraction-limited operation.
Comparing NEO Search Telescopes
Myhrvold, Nathan
2015-01-01
Multiple terrestrial and space-based telescopes have been proposed for detecting and tracking near-Earth objects (NEOs). Detailed simulations of the search performance of these systems have used complex computer codes that are not widely available, which hinders accurate cross- comparison of the proposals and obscures whether they have consistent assumptions. Moreover, some proposed instruments would survey infrared (IR) bands, whereas others would operate in the visible band, and differences among asteroid thermal and visible light models used in the simulations further complicate like-to-like comparisons. I use simple physical principles to estimate basic performance metrics for the ground-based Large Synoptic Survey Telescope and three space-based instruments - Sentinel, NEOCam, and a Cubesat constellation. The performance is measured against two different NEO distributions, the Bottke et al. distribution of general NEOs, and the Veres et al. distribution of earth impacting NEO. The results of the comparis...
Mandal, Pranshu; Kumar, Pratik; Yelikar, Anjali; Soni, Kanchan; T, Vineeth Krishna
2016-01-01
We have developed an affordable, portable college level radio telescope for amateur radio astronomy which can be used to provide hands-on experience with the fundamentals of a radio telescope and an insight into the realm of radio astronomy. With our set-up one can measure brightness temperature and flux of the Sun at 11.2 GHz and calculate the beam width of the antenna. The set-up uses commercially available satellite television receiving system and parabolic dish antenna. We report the detection of point sources like Saturn and extended sources like the galactic arm of the Milky way. We have also developed python pipeline, which are available for free download, for data acquisition and visualization.
Cooray, Asantha R.; Origins Space Telescope Study Team
2017-01-01
The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. I will summarize the OST STDT, mission design and instruments, key science drivers, and the study plan over the next two years.
Strebel, Christoph
2006-01-01
Galileo's publication of observations made with his newly reinvented telescope provoked a fierce debate. In April 1610 Martinus Horky, a young Bohemian astronomer, had an opportunity to make his own observations with Galileo's telescope in the presence of Antonio Magini and other astronomers. Horky and the other witnesses denied the adequacy of Galileo's telescope and therefore the bona fides of his discoveries. Kepler conjectured Horky as well as all his witnesses to be myopic. But Kepler's objection could not stop the publication of Horky's Peregrinatio contra nuncium sidereum (Modena, 1610), the first printed refutation of Galileo's Sidereus nuncius. In his treatise, Horky adresses four questions: 1) Do the four newly observed heavenly bodies actually exist? Horky denies their existence on various grounds: a) God, as every astronomer teaches, has created only seven moveable heavenly bodies and astronomical knowledge originates in God, too. b) Heavenly bodies are either stars or planets. Galileo's moveable heavenly bodies fit into neither category. c) If they do exist, why have they not already been observed by other scholars? Horky concludes that there are no such heavenly bodies. 2) What are these phenomena? They are purely artefactual, and produced by Galileo's telescope. 3) How are they like? Galileo's "stars" are so small as to be almost invisible. Galileo claims that he has measured their distances from each other. This however is impossible due to their diminutive size and other observational problems. Hence, Galileo's claim is a further proof that he is a fraud. 4) Why are they? For Galileo they are a chance to earn money but for astronomers like Horky they are a reason to offer thanks and honour to God. Horky's treatise was favourably received by the enemies of Galileo. But Kepler's critique was devastating. After calling on Kepler in Prague, Horky had to revoke the contents of his book.
Connaughton, Valerie
2014-03-01
The Cherenkov Telescope Array (CTA) is a large collaborative effort dedicated to the design and operation of the next-generation ground-based very high-energy gamma-ray observatory. CTA will improve by about one order of magnitude the sensitivity with respect to the current major arrays (VERITAS, H.E.S.S., and MAGIC) in the core energy range of 100 GeV to 10 TeV, and will extend the viability of the imaging atmospheric Cherenkov technique (IACT) down to tens of GeV and above 100 TeV. In order to achieve such improved performance at both a northern and southern CTA site, four 23m diameter Large Size Telescopes (LST) optimized for low energy gamma rays will be deployed close to the centre of the array. A larger number of Medium Size Telescopes (MST) will be optimized for the core IACT energy range. The southern site will include 25 12m single-mirror MSTs and a US contribution of up to 24 novel dual-mirror design Schwarzschild-Couder (SC) type MSTs with a primary mirror of 9.5m diameter, and will also include an array of Small Size Telescopes (SST) to observe the highest-energy gamma rays from galactic sources. The SSTs can be smaller and more widely separated because more energetic gamma rays produce a larger Cherenkov light pool with many photons. The SSTs achieve a large collection area by covering a wide (10 sq km) footprint on the ground. The CTA project is finishing its preparatory phase, and the pre-production phase will start this year. I will review the status and the expected performance of CTA as well as the main scientific goals for the observatory.
Hubble Space Telescope satellite
Mitchell, R. E.
1985-01-01
The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.
Fast Fourier transform telescope
Tegmark, Max; Zaldarriaga, Matias
2009-04-01
We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore’s law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog2N rather than N2) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.
From Maxwell's theory of Saturn's rings to the negative mass instability.
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.
SOAR Telescope Progress Report
Sebring, T.; Cecil, G.; Krabbendam, V.
1999-12-01
The 4.3m SOAR telescope is fully funded and under construction. A partnership between the country of Brazil, NOAO, Michigan State University, and the University of North Carolina at Chapel Hill, SOAR is being designed for high-quality imaging and imaging spectroscopy in the optical and near-IR over a field of view up to 12' diameter. US astronomers outside MSU and UNC will access 30% of the observing time through the standard NOAO TAC process. The telescope is being designed to support remote and synoptic observations. First light is scheduled for July 2002 at Cerro Pachon in Chile, a site with median seeing of 2/3" at 500 nm. The telescope will be operated by CTIO. Corning Inc. has fused the mirror blanks from boules of ULE glass. RSI in Richardson, Texas and Raytheon Optical Systems Inc. in Danbury, Conn. are designing and will fabricate the mount and active optics systems, respectively. The mount supports an instrument payload in excess of 5000 kg, at 2 Nasmyth locations and 3 bent Cass. ports. The mount and facility building have space for a laser to generate an artificial AO guide star. LabVIEW running under the Linux OS on compactPCI hardware has been adopted to control all telescope, detector, and instrument systems. The primary mirror is 10 cm thick and will be mounted on 120 electro-mechanical actuators to maintain its ideal optical figure at all elevations. The position of the light-weighted secondary mirror is adjusted to maintain collimation through use of a Shack-Hartmann wavefront sensor. The tertiary mirror feeds instruments and also jitters at up to 50 Hz to compensate for telescope shake and atmosphere wavefront tilt. The dome is a steel framework, with fiberglass panels. Air in the observing volume will be exchanged with that outside every few minutes by using large fans under computer control. All systems will be assembled and checked at the manufacturer's facility, then shipped to Chile. A short integration period is planned, and limited science
Mathematical analysis of plasmonic resonances for nanoparticles: The full Maxwell equations
Ammari, Habib; Ruiz, Matias; Yu, Sanghyeon; Zhang, Hai
2016-09-01
In this paper we use the full Maxwell equations for light propagation in order to analyze plasmonic resonances for nanoparticles. We mathematically define the notion of plasmonic resonance and analyze its shift and broadening with respect to changes in size, shape, and arrangement of the nanoparticles, using the layer potential techniques associated with the full Maxwell equations. We present an effective medium theory for resonant plasmonic systems and derive a condition on the volume fraction under which the Maxwell-Garnett theory is valid at plasmonic resonances.
Study of the Maxwell Montes region on Venus by Venera 15 and Venera 16 space probes
Energy Technology Data Exchange (ETDEWEB)
Kotel' nikov, V.A.; Akim, Eh.L.; Aleksandrov, Yu.N.
1984-12-01
The data on geological structure of Maxwell Montes, the highest region of Venus, are obtained by means of the radar system of the Venera 15 and 16 spacecrafts, providing high surface resolution. It is found that Maxwell Montes and significant part of the locality are formed by horizontal tectonic deformation of compression origin, approximating them to folded mountains of the Earth. Adjacent to the Maxwell Montes plains, possibly, are formed with basaltic extrusions similar to seatype plain of other earth-group planetary body. Patera Cleopatra depression is similar to double-ring craters of impact origin rather than volcanic calderas.
The Planck Telescope reflectors
Stute, Thomas
2004-09-01
The mechanical division of EADS-Astrium GmbH, Friedrichshafen is currently engaged with the development, manufacturing and testing of the advanced dimensionally stable composite reflectors for the ESA satellite borne telescope Planck. The objective of the ESA mission Planck is to analyse the first light that filled the universe, the cosmic microwave background radiation. Under contract of the Danish Space Research Institute and ESA EADS-Astrium GmbH is developing the all CFRP primary and secondary reflectors for the 1.5-metre telescope which is the main instrument of the Planck satellite. The operational frequency ranges from to 25 GHz to 1000 GHz. The demanding high contour accuracy and surface roughness requirements are met. The design provides the extreme dimensional stability required by the cryogenic operational environment at around 40 K. The elliptical off-axis reflectors display a classical lightweight sandwich design with CFRP core and facesheets. Isostatic mounts provide the interfaces to the telescope structure. Protected VDA provides the reflecting surface. The manufacturing is performed at the Friedrichshafen premises of EADS-Space Transportation GmbH, the former Dornier composite workshops. Advanced manufacturing technologies like true angle lay-up by CNC fibre placement and filament winding are utilized. The protected coating is applied at the CAHA facilities at the Calar Alto Observatory, Spain. The exhaustive environmental testing is performed at the facilities of IABG, Munich (mechanical testing) and for the cryo-optical tests at CSL Liege. The project is in advanced state with both Qualification Models being under environmental testing. The flight models will be delivered in 2004. The paper gives an overview over the requirements and the main structural features how these requirements are met. Special production aspects and available test results are reported.
Trading coherence and entropy by a quantum Maxwell demon
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.
Marginal and Irrelevant Disorder in Einstein-Maxwell backgrounds
García-García, Antonio M
2015-01-01
We study analytically the effect of a weak random chemical potential of zero average in an Einstein-Maxwell background. For uncorrelated disorder this perturbation is relevant however we show that it can become marginal or even irrelevant by tuning disorder correlations. At zero temperature we find that the correction to the conductivity for irrelevant perturbations is always negative. In the marginal case, in order to renormalize a logarithmic divergence, we carry out a resummation of the perturbative expansion of the metric that leads to a Lifshitz-like geometry in the infrared. Disorder in this case also induces a logarithmic correction to the conductivity that diverges in the limit of infinite system size. This is reminiscent of the situation in two dimensional weakly disordered metals which suggests an instability of the $AdS_4$ metric and therefore the possibility of a metal-insulator transition. At finite temperature the black hole acquires an effective charge and the thermal conductivity has the expec...
Two versions of Maxwell's equations and the nature of light
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.
Clausius/Cosserat/Maxwell/Weyl Equations: The Viral Theorem Revisited
Pommaret, Jean-François
2015-01-01
In 1870, R. Clausius found the virial theorem which amounts to introduce the trace of the stress tensor when studying the foundations of thermodynamics, as a way to relate the absolute temperature of an ideal gas to the mean kinetic energy of its molecules. In 1901, H. Poincar{\\'e} introduced a duality principle in analytical mechanics in order to study lagrangians invariant under the action of a Lie group of transformations. In 1909, the brothers E. and F. Cosserat discovered another approach for studying the same problem though using quite different equations. In 1916, H. Weyl considered again the same problem for the conformal group of transformations, obtaining at the same time the Maxwell equations and an additional specific equation also involving the trace of the impulsion-energy tensor. Finally, having in mind the space-time formulation of electromagnetism and the Maurer-Cartan equations for Lie groups, gauge theory has been created by C.N. Yang and R.L. Mills in 1954 as a way to introduce in physics ...
Circuital model for the Maxwell Fish Eye perfect drain
Gonzalez, Juan C; Minano, Juan C; Benitez, Pablo
2012-01-01
Perfect drain for the Maxwell Fish Eye (MFE) is a non-magnetic dissipative region placed in the focal point to absorb all the incident radiation without reflection or scattering. The perfect drain was recently designed as a material with complex electrical permittivity that depends on frequency. However, this material is only a theoretical material, so it can not be used in practical devices. Recently, the perfect drain has been claimed as necessary to achieve super-resolution [Leonhard 2009, New J. Phys. 11 093040], which has increased the interest for practical perfect drains suitable for manufacturing. Here, we analyze the super-resolution properties of a device equivalent to the MFE, known as Spherical Geodesic Waveguide (SGW), loaded with the perfect drain. In the SGW the source and drain are implemented with coaxial probes. The perfect drain is realized using a circuit (made of a resistance and a capacitor) connected to the drain coaxial probes. Super-resolution analysis for this device is done in Comso...
Do biological molecular machines act as Maxwell's demons?
Kurzynski, Michal
2014-01-01
In the intention of its creator, Maxwell's demon was thought to be an intelligent being able to perform work at the expense of the entropy reduction of a closed operating system. The perplexing notion of the demon's intelligence was formalized in terms of the memory and information processing by Szilard and followers. A non-informational formulation of the problem was proposed by Smoluchowski and popularized by Feynman as the ratchet and pawl machine. A. F. Huxley and followers adopted this way of thinking to propose numerous ratchet mechanisms of the protein molecular machines action, but no entropy reduction takes place for these models. More general models of protein dynamics have been proposed with a number of intramolecular states organized in a network of stochastic transitions. Here, a computer realization of such a network is investigated, displaying, like networks of the systems biology, a transition from the fractal organization on a small length-scale to the small-world organization on the large le...
GLOBAL SUPERCONVERGENCE OF THE MIXED FINITE ELEMENT METHODS FOR 2-D MAXWELL EQUATIONS
Institute of Scientific and Technical Information of China (English)
Jia-fu Lin; Qun Lin
2003-01-01
Superconvergence of the mixed finite element methods for 2-d Maxwell equations isstudied in this paper. Two order of superconvergent factor can be obtained for the k-thNedelec elements on the rectangular meshes.
Christov, Christo I
2011-01-01
We show that the linearized equations of the incompressible elastic medium admit a `Maxwell form' in which the shear component of the stress vector plays the role of the electric field, and the vorticity plays the role of the magnetic field. Conversely, the set of dynamic Maxwell equations are strict mathematical corollaries from the governing equations of the incompressible elastic medium. This suggests that the nature of `electromagnetic field' may actually be related to an elastic continuous medium. The analogy is complete if the medium is assumed to behave as fluid in shear motions, while it may still behave as elastic solid under compressional motions. Then the governing equations of the elastic fluid are re-derived in the Eulerian frame by replacing the partial time derivatives by the properly invariant (frame indifferent) time rates. The `Maxwell from' of the frame indifferent formulation gives the frame indifferent system that is to replace the Maxwell system. This new system comprises terms already p...
Maxwell's color statistics: from reduction of visible errors to reduction to invisible molecules.
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.
Conformal symmetry and the role of torsion in a Maxwell-Einstein system
Energy Technology Data Exchange (ETDEWEB)
Tiemblo, A.; Tresguerres, R. (Instituto de Fisica Fundamental, Madrid (Spain))
1991-08-01
We develop a formalism which allows to treat Weyl symmetry with torsion as the gauge theory of the conformal group. The results of the standard Einstein-Gartan theory are generalized and applied to the Maxwell-Einstein case. (orig.).
Contaminants investigation of the Maxwell National Wildlife Refuge, New Mexico, 1989
US Fish and Wildlife Service, Department of the Interior — This investigation was conducted to determine the nature and extent of contaminants at Maxwell National Wildlife Refuge (Refuge) and how they may affect fish and...
Electricity and magnetism for mathematicians a guided path from Maxwell to Yang-Mills
Garrity, Thomas A
2015-01-01
This text is an introduction to some of the mathematical wonders of Maxwell's equations. These equations led to the prediction of radio waves, the realization that light is a type of electromagnetic wave, and the discovery of the special theory of relativity. In fact, almost all current descriptions of the fundamental laws of the universe can be viewed as deep generalizations of Maxwell's equations. Even more surprising is that these equations and their generalizations have led to some of the most important mathematical discoveries of the past thirty years. It seems that the mathematics behind Maxwell's equations is endless. The goal of this book is to explain to mathematicians the underlying physics behind electricity and magnetism and to show their connections to mathematics. Starting with Maxwell's equations, the reader is led to such topics as the special theory of relativity, differential forms, quantum mechanics, manifolds, tangent bundles, connections, and curvature.
Noundjeu, P
2003-01-01
Using the iterative Scheme we prove the local existence and uniqueness of solutions of the spherically symmetric Einstein-Vlasov-Maxwell system with small initial data. We prove a continuation criterion to global in-time solutions.
Magellan Telescopes operations 2008
Osip, David J.; Phillips, Mark M.; Palunas, Povilas; Perez, Frank; Leroy, M.
2008-07-01
The twin 6.5m Magellan Telescopes have been in routine operations at the Las Campanas Observatory in the Chilean Andes since 2001 and 2002 respectively. The telescopes are owned and operated by Carnegie for the benefit of the Magellan consortium members (Carnegie Institution of Washington, Harvard University, the University of Arizona, Massachusetts Institute of Technology, and the University of Michigan). This paper provides an up to date review of the scientific, technical, and administrative structure of the 'Magellan Model' for observatory operations. With a modest operations budget and a reasonably small staff, the observatory is operated in the "classical" mode, wherein the visiting observer is a key member of the operations team. Under this model, all instrumentation is supplied entirely by the consortium members and the various instrument teams continue to play a critical support role beyond initial deployment and commissioning activities. Here, we present a critical analysis of the Magellan operations model and suggest lessons learned and changes implemented as we continue to evolve an organizational structure that can efficiently deliver a high scientific return for the investment of the partners.
Bigongiari, Ciro
2016-01-01
The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indications that the known sources represent only the tip of the iceberg. A major step in sensitivity is needed to increase the number of detected sources, observe short time-scale variability and improve morphological studies of extended sources. An extended energy coverage is advisable to observe far-away extragalactic objects and improve spectral analysis. CTA aims to increase the sensitivity by an order of magnitude compared to current facilities, to extend the accessible gamma-ray energies from a few tens of GeV to a hundred o...
Mazin, D; Teshima, M
2016-01-01
The Cherenkov Telescope Array (CTA) observatory will be deployed over two sites in the two hemispheres. Both sites will be equipped with four Large Size Telescopes (LSTs), which are crucial to achieve the science goals of CTA in the 20-200 GeV energy range. Each LST is equipped with a primary tessellated mirror dish of 23 m diameter, supported by a structure made mainly of carbon fibre reinforced plastic tubes and aluminum joints. This solution guarantees light weight (around 100 tons), essential for fast repositioning to any position in the sky in <20 seconds. The camera is composed of 1855 photomultiplier tubes and embeds the control, readout and trigger electronics. The detailed design is now complete and production of the first LST, which will serve as a prototype for the remaining seven, is ongoing. The installation of the first LST at the Roque de los Muchachos Observatory on the Canary island of La Palma (Spain) started in July 2016. In this paper we will outline the technical solutions adopted to f...
Upgrade of the MAGIC telescopes
Mazin, Daniel; Garczarczyk, Markus; Giavitto, Gianluca; Sitarek, Julian
2014-01-01
The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. With 17m diameter mirror dishes and ultra-fast electronics, they provide an energy threshold as low as 50 GeV for observations at low zenith angles. The first MAGIC telescope was taken in operation in 2004 whereas the second one joined in 2009. In 2011 we started a major upgrade program to improve and to unify the stereoscopic system of the two similar but at that time different telescopes. Here we report on the upgrade of the readout electronics and digital trigger of the two telescopes, the upgrade of the camera of the MAGIC I telescope as well as the commissioning of the system after this major upgrade.
Construction of a new wastewater treatment plant, building 676, route Maxwell
SC Unit
2008-01-01
A new wastewater treatment plant is being constructed on Route Maxwell to treat the effluents from the TS/MME/CCS surface treatment workshops. For this purpose, excavation work is being performed in two separate locations along Route Maxwell, causing a slight disruption to traffic in these areas. Site access through Gate C should, however, be maintained. The work is scheduled to continue through until February 2009.
Construction of a new waste-water treatment plant, building 676, route Maxwell
TS Department
2008-01-01
A new waste-water treatment plant is being constructed on Route Maxwell to treat the effluents from the TS/MME/CCS surface treatment workshops. For this purpose, excavation work is being performed in two separate locations along Route Maxwell, causing a slight disruption to traffic in these areas. Site access through Gate C should, however, be maintained. The work is scheduled to continue until February 2009.
Variational principles for the guiding-center Vlasov-Maxwell equations
Brizard, A J
2016-01-01
The Lagrange, Euler, and Euler-Poincar\\'{e} variational principles for the guiding-center Vlasov-Maxwell equations are presented. Each variational principle presents 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.
Global Existence of Smooth Solutions of Compressible Bipolar Euler-Maxwell Equations
Institute of Scientific and Technical Information of China (English)
XU Qian-jin; LI Xin; FENG Yue-hong
2013-01-01
The bipolar compressible Euler-Maxwell equations as a fluid dynamic model arising from plasma physics to describe the dynamics of the compressible electrons and ions is investigated.This work is concerned with three-dimensional Euler-Maxwell equations with smooth periodic solutions.With the help of the symmetry operator techniques and energy method,the global smooth solution with small amplitude is constructed around a constant equilibrium solution with asymptotic stability property.
PARTIAL COMPACTNESS FOR LANDAU-LIFSHITZ MAXWELL EQUATION IN TWO-DIMENSION
Institute of Scientific and Technical Information of China (English)
Kou Yanlei; Diug Shijin
2011-01-01
We study the partial regularity of weak solutions to the 2-dimensional Landau- Lifshitz equations coupled with time dependent Maxwell equations by Ginzburg-Landau type approximation. Outside an energy concentration set of locally finite 2-dimensional parabolic Hausdorff measure, we prove the uniform local C∞ bounds for the approaching solutions and then extract a subsequence converging to a global weak solution of the Landau-Lifshitz-Maxwell equations which are smooth away from finitely many points.
Institute of Scientific and Technical Information of China (English)
Xia Ji; Wei Cai; Pingwen Zhang
2008-01-01
In this paper, we analyze the transmission and reflection properties of a high order discontinuous Galerkin method for dispersive Maxwell's equations, originally proposed by Lu et al. [J. Comput. Phys. 200 (2004), pp. 549-580]. We study the reflection and transmission properties of the numerical method for up to second-order polynomial elements for one-and two-dimensional Maxwell's equations with rectangular meshes. High order accuracy has been shown for reflection and transmission coefficients near material interfaces.
Grid Integration of Robotic Telescopes
Breitling, F; Enke, H
2008-01-01
Robotic telescopes and grid technology have made significant progress in recent years. Both innovations offer important advantages over conventional technologies, particularly in combination with one another. Here, we introduce robotic telescopes used by the Astrophysical Institute Potsdam as ideal instruments for building a robotic telescope network. We also discuss the grid architecture and protocols facilitating the network integration that is being developed by the German AstroGrid-D project. Finally, we present three user interfaces employed for this purpose.
Near Earth Object Survey Telescope
Institute of Scientific and Technical Information of China (English)
2011-01-01
The Near Earth Object Survey Telescope （NEOST）, located at the Xuyi station of the Purple Mountain Observatory, is a telescope with the most powerful detection capacity, the highest efficiency and the best performance in the fields of near Earth object survey and optical imaging in China. NEOST is an 171.8 Schmidt type telescope with a 1.20 meter primary mirror and a 1.04 meter corrector,
Language Individuation and Marker Words: Shakespeare and His Maxwell's Demon.
Directory of Open Access Journals (Sweden)
John Marsden
Full Text Available 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.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%.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.
Global smooth flows for compressible Navier-Stokes-Maxwell equations
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.
Tracer diffusion coefficients in a sheared inelastic Maxwell gas
Garzó, Vicente; Trizac, Emmanuel
2016-07-01
We study the transport properties of an impurity in a sheared granular gas, in the framework of the Boltzmann equation for inelastic Maxwell models. We investigate here the impact of a nonequilibrium phase transition found in such systems, where the tracer species carries a finite fraction of the total kinetic energy (ordered phase). To this end, the diffusion coefficients are first obtained for a granular binary mixture in spatially inhomogeneous states close to the simple shear flow. In this situation, the set of coupled Boltzmann equations are solved by means of a Chapman-Enskog-like expansion around the (local) shear flow distributions for each species, thereby retaining all the hydrodynamic orders in the shear rate a. Due to the anisotropy induced by the shear flow, three tensorial quantities D ij , D p,ij , and D T,ij are required to describe the mass transport process instead of the conventional scalar coefficients. These tensors are given in terms of the solutions of a set of coupled algebraic equations, which can be exactly solved as functions of the shear rate a, the coefficients of restitution {αsr} and the parameters of the mixture (masses and composition). Once the forms of D ij , D p,ij , and D T,ij are obtained for arbitrary mole fraction {{x}1}={{n}1}/≤ft({{n}1}+{{n}2}\\right) (where n r is the number density of species r), the tracer limit ({{x}1}\\to 0 ) is carefully considered for the above three diffusion tensors. Explicit forms for these coefficients are derived showing that their shear rate dependence is significantly affected by the order-disorder transition.
Language Individuation and Marker Words: Shakespeare and His Maxwell's Demon
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
Gamma-Ray Telescopes: 400 Years of Astronomical Telescopes
Gehrels, Neil; Cannizzo, John K.
2010-01-01
The last half-century has seen dramatic developments in gamma-ray telescopes, from their initial conception and development through to their blossoming into full maturity as a potent research tool in astronomy. Gamma-ray telescopes are leading research in diverse areas such as gamma-ray bursts, blazars, Galactic transients, and the Galactic distribution of Al-26.
Building Medium Size Telescope Structures for the Cherenkov Telescope Array
Schulz, A; Oakes, L; Schlenstedt, S; Schwanke, U
2016-01-01
The Cherenkov Telescope Array (CTA) is the future instrument in ground-based gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. Its sensitivity will surpass that of current generation experiments by a factor $\\sim$10, facilitated by telescopes of three sizes. The performance in the core energy regime will be dominated by Medium Size Telescopes (MST) with a reflector of 12 m diameter. A full-size mechanical prototype of the telescope structure has been constructed in Berlin. The performance of the prototype is being evaluated and optimisations, among others, facilitating the assembly procedure and mass production possibilities are being implemented. We present the current status of the developments from prototyping towards pre-production telescopes, which will be deployed at the final site.
The neutrino telescope ANTARES
Directory of Open Access Journals (Sweden)
Gleixner Andreas
2014-04-01
Full Text Available The ANTARES neutrino telescope is currently the largest neutrino detector in the Northern Hemisphere. The detector consists of a three-dimensional array of 885 photomultiplier tubes, distributed along 12 lines, located at a depth of 2500 m in the Mediterranean Sea. The purpose of the experiment is the detection of high-energy cosmic neutrinos. The detection principle is based on the observation of Cherenkov-Light emitted by muons resulting from charged-current interactions of muon neutrinos in the vicinity of the detection volume. The main scientific targets of ANTARES include the search for astrophysical neutrino point sources, the measurement of the diffuse neutrino flux and the indirect search for dark matter.
Spectroradiometry with Space Telescopes
Pauluhn, Anuschka; Smith, Peter L; Colina, Luis
2015-01-01
Radiometry has been of fundamental importance in astronomy from the early beginnings. Initially, astronomers had their own radiometric system, based on extraterrestrial standards, namely the irradiance of stars expressed in visual magnitudes. Observing and comparing magnitudes in specific spectral bands then led to the astronomical spectrophotometry. The advent of astronomical high-resolution spectroscopy offered the possibility to interpret observations through physical models of stellar atmospheres. Such models had to be constructed based on physics-related units, and such units, rather than magnitudes, were then used for observational tests of the models. In this review, we provide an overview of how to achieve a valid laboratory calibration, and discuss ways to reliably extend this calibration to the spectroscopic telescope's performance in space. Recently, the quest for independent calibrations traceable to laboratory standards has become a well-supported aim, and has led to plans for now also launching ...
The ANTARES neutrino telescope
Zornoza, Juan de Dios
2012-01-01
The ANTARES collaboration completed the installation of the first neutrino detector in the sea in 2008. It consists of a three dimensional array of 885 photomultipliers to gather the Cherenkov photons induced by relativistic muons produced in charged-current interactions of high energy neutrinos close to/in the detector. The scientific scope of neutrino telescopes is very broad: the origin of cosmic rays, the origin of the TeV photons observed in many astrophysical sources or the nature of dark matter. The data collected up to now have allowed us to produce a rich output of physics results, including the map of the neutrino sky of the Southern hemisphere, search for correlations with GRBs, flaring sources, gravitational waves, limits on the flux produced by dark matter self-annihilations, etc. In this paper a review of these results is presented.
Composite telescope technology
Chen, Peter C.; Rabin, Douglas
2014-07-01
We report the development of optical mirrors based on polymer matrix composite materials. Advantages of this technology are low cost and versatility. By using appropriate combinations of polymers and various metallic and nonmetallic particles and fibers, the properties of the materials can be tailored to suit a wide variety of applications. We report the fabrication and testing of flat and curved mirrors made with metal powders, multiple mirrors replicated with high degree of uniformity from the same mandrels, cryogenic testing, mirrors made of ferromagnetic materials that can be actively or adaptively controlled by non-contact actuation, optics with very smooth surfaces made by replication, and by spincasting. We discuss development of a new generation of ultra-compact, low power active optics and 3D printing of athermal telescopes.
European Solar Telescope: Progress status
Collados, M.; Bettonvil, F.C.M.; Cavaller, L.; Ermolli, I.; Gelly, B.; Pérez, A.; Socas-Navarro, H.; Soltau, D.; Volkmer, R.
2010-01-01
In this paper, the present status of the development of the design of the European Solar Telescope is described. The telescope is devised to have the best possible angular resolution and polarimetric performance, maximizing the throughput of the whole system. To that aim, adaptive optics and multi-c
Seismic Imager Space Telescope
Sidick, Erkin; Coste, Keith; Cunningham, J.; Sievers,Michael W.; Agnes, Gregory S.; Polanco, Otto R.; Green, Joseph J.; Cameron, Bruce A.; Redding, David C.; Avouac, Jean Philippe; Ampuero, Jean Paul; Leprince, Sebastien; Michel, Remi
2012-01-01
A concept has been developed for a geostationary seismic imager (GSI), a space telescope in geostationary orbit above the Pacific coast of the Americas that would provide movies of many large earthquakes occurring in the area from Southern Chile to Southern Alaska. The GSI movies would cover a field of view as long as 300 km, at a spatial resolution of 3 to 15 m and a temporal resolution of 1 to 2 Hz, which is sufficient for accurate measurement of surface displacements and photometric changes induced by seismic waves. Computer processing of the movie images would exploit these dynamic changes to accurately measure the rapidly evolving surface waves and surface ruptures as they happen. These measurements would provide key information to advance the understanding of the mechanisms governing earthquake ruptures, and the propagation and arrest of damaging seismic waves. GSI operational strategy is to react to earthquakes detected by ground seismometers, slewing the satellite to point at the epicenters of earthquakes above a certain magnitude. Some of these earthquakes will be foreshocks of larger earthquakes; these will be observed, as the spacecraft would have been pointed in the right direction. This strategy was tested against the historical record for the Pacific coast of the Americas, from 1973 until the present. Based on the seismicity recorded during this time period, a GSI mission with a lifetime of 10 years could have been in position to observe at least 13 (22 on average) earthquakes of magnitude larger than 6, and at least one (2 on average) earthquake of magnitude larger than 7. A GSI would provide data unprecedented in its extent and temporal and spatial resolution. It would provide this data for some of the world's most seismically active regions, and do so better and at a lower cost than could be done with ground-based instrumentation. A GSI would revolutionize the understanding of earthquake dynamics, perhaps leading ultimately to effective warning
General eigenstates of Maxwell's equations in a two-constituent composite medium
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.
Operating a heterogeneous telescope network
Allan, Alasdair; Bischoff, Karsten; Burgdorf, Martin; Cavanagh, Brad; Christian, Damien; Clay, Neil; Dickens, Rob; Economou, Frossie; Fadavi, Mehri; Frazer, Stephen; Granzer, Thomas; Grosvenor, Sandy; Hessman, Frederic V.; Jenness, Tim; Koratkar, Anuradha; Lehner, Matthew; Mottram, Chris; Naylor, Tim; Saunders, Eric S.; Solomos, Nikolaos; Steele, Iain A.; Tuparev, Georg; Vestrand, W. Thomas; White, Robert R.; Yost, Sarah
2006-06-01
In the last few years the ubiquitous availability of high bandwidth networks has changed the way both robotic and non-robotic telescopes operate, with single isolated telescopes being integrated into expanding "smart" telescope networks that can span continents and respond to transient events in seconds. The Heterogeneous Telescope Networks (HTN)* Consortium represents a number of major research groups in the field of robotic telescopes, and together we are proposing a standards based approach to providing interoperability between the existing proprietary telescope networks. We further propose standards for interoperability, and integration with, the emerging Virtual Observatory. We present the results of the first interoperability meeting held last year and discuss the protocol and transport standards agreed at the meeting, which deals with the complex issue of how to optimally schedule observations on geographically distributed resources. We discuss a free market approach to this scheduling problem, which must initially be based on ad-hoc agreements between the participants in the network, but which may eventually expand into a electronic market for the exchange of telescope time.
Why systems engineering on telescopes?
Swart, Gerhard P.; Meiring, Jacobus G.
2003-02-01
Although Systems Engineering has been widely applied to the defence industry, many other projects are unaware of its potential benefits when correctly applied, assuming that it is an expensive luxury. It seems that except in a few instances, telescope projects are no exception, prompting the writing of this paper. The authors postulate that classical Systems Engineering can and should be tailored, and then applied to telescope projects, leading to cost, schedule and technical benefits. This paper explores the essence of Systems Engineering and how it can be applied to any complex development project. The authors cite real-world Systems Engineering examples from the Southern African Large Telescope (SALT). The SALT project is the development and construction of a 10m-class telescope at the price of a 4m telescope. Although SALT resembles the groundbreaking Hobby-Eberly Telescope (HET) in Texas, the project team are attempting several challenging changes to the original design, requiring a focussed engineering approach and discernment in the definition of the telescope requirements. Following a tailored Systems Engineering approach on this project has already enhanced the quality of decisions made, improved the fidelity of contractual specifications for subsystems, and established criteria testing their performance. Systems Engineering, as applied on SALT, is a structured development process, where requirements are formally defined before the award of subsystem developmental contracts. During this process conceptual design, modeling and prototyping are performed to ensure that the requirements were realistic and accurate. Design reviews are held where the designs are checked for compliance with the requirements. Supplier factory and on-site testing are followed by integrated telescope testing, to verify system performance against the specifications. Although the SALT project is still far from completion, the authors are confident that the present benefits from
The Automatic Telescope Network (ATN)
Mattox, J R
1999-01-01
Because of the scheduled GLAST mission by NASA, there is strong scientific justification for preparation for very extensive blazar monitoring in the optical bands to exploit the opportunity to learn about blazars through the correlation of variability of the gamma-ray flux with flux at lower frequencies. Current optical facilities do not provide the required capability.Developments in technology have enabled astronomers to readily deploy automatic telescopes. The effort to create an Automatic Telescope Network (ATN) for blazar monitoring in the GLAST era is described. Other scientific applications of the networks of automatic telescopes are discussed. The potential of the ATN for science education is also discussed.
Formation flight astronomical survey telescope
Tsunemi, Hiroshi
2012-03-01
Formation Flight Astronomical Survey Telescope (FFAST) is a project for hard X-ray observation. It consists of two small satellites; one (telescope satellite) has a super mirror covering the energy range up to 80 keV while the other (detector satellite) has an scintillator deposited CCD (SDCCD) having good spatial resolution and high efficiency up to 100 keV. Two satellites will be put into individual Kepler orbits forming an X-ray telescope with a focal length of 20 m. They will be not in pointing mode but in survey mode to cover a large sky region.
Infrared up-conversion telescope
DEFF Research Database (Denmark)
2014-01-01
There is presented to an up-conversion infrared telescope (110) arranged for imaging an associated scene (130), wherein the up-conversion infrared telescope (110) comprises a non-linear crystal (120) arranged for up-conversion of infrared electromagnetic radiation, and wherein a first optical...... at the plane of the external image) which is denominated D2 and wherein D1 is larger than a second diameter D2 and wherein the telescope further comprises a third optical component (103) and a fourth optical component (104); arranged for re-imaging the first image into a second image of the back-focal plane...
Bhavnagar Telescope: the most widely travelled telescope in the country
Rao, N Kameswara; Vagiswari, A
2014-01-01
In the last decade of the 19th century Maharaja Takhtasingji Observatory was built at Poona (1888-1912) under the supervision of K.D.Naegamavala, with the grant from Maharaja of Bhavnagar (from where the name Bhavnagar Telescope must have originated. The story of this telescope from its inception to the current status is traced. IIA Archives has been extensively used to resource information for this note.
Ice Middleware in the New Solar Telescope's Telescope Control System
Shumko, S.
2009-09-01
The Big Bear Solar Observatory (BBSO) is now in the process of assembling and aligning its 1.6 m New Solar Telescope (NST). There are many challenges controlling NST and one of them is establishing reliable and robust communications between different parts of the Telescope Control System (TCS). For our TCS we selected Ice (Internet communication engine) from ZeroC, Inc. In this paper we discuss advantages of the Ice middleware, details of implementation and problems we face implementing it.
The small size telescope projects for the Cherenkov Telescope Array
,
2015-01-01
The small size telescopes (SSTs), spread over an area of several square km, dominate the CTA sensitivity in the photon energy range from a few TeV to over 100 TeV, enabling for the detailed exploration of the very high energy gamma-ray sky. The proposed telescopes are innovative designs providing a wide field of view. Two of them, the ASTRI (Astrophysics con Specchi a Tecnologia Replicante Italiana) and the GCT (Gamma-ray Cherenkov Telescope) telescopes, are based on dual mirror Schwarzschild-Couder optics, with primary mirror diameters of 4 m. The third, SST-1M, is a Davies-Cotton design with a 4 m diameter mirror. Progress with the construction and testing of prototypes of these telescopes is presented. The SST cameras use silicon photomultipliers, with preamplifier and readout/trigger electronics designed to optimize the performance of these sensors for (atmospheric) Cherenkov light. The status of the camera developments is discussed. The SST sub-array will consist of about 70 telescopes at the CTA souther...
Lightweighted ZERODUR for telescopes
Westerhoff, T.; Davis, M.; Hartmann, P.; Hull, T.; Jedamzik, R.
2014-07-01
The glass ceramic ZERODUR® from SCHOTT has an excellent reputation as mirror blank material for earthbound and space telescope applications. It is known for its extremely low coefficient of thermal expansion (CTE) at room temperature and its excellent CTE homogeneity. Recent improvements in CNC machining at SCHOTT allow achieving extremely light weighted substrates up to 90% incorporating very thin ribs and face sheets. In 2012 new ZERODUR® grades EXPANSION CLASS 0 SPECIAL and EXTREME have been released that offer the tightest CTE grades ever. With ZERODUR® TAILORED it is even possible to offer ZERODUR® optimized for customer application temperature profiles. In 2013 SCHOTT started the development of a new dilatometer setup with the target to drive the industrial standard of high accuracy thermal expansion metrology to its limit. In recent years SCHOTT published several paper on improved bending strength of ZERODUR® and lifetime evaluation based on threshold values derived from 3 parameter Weibull distribution fitted to a multitude of stress data. ZERODUR® has been and is still being successfully used as mirror substrates for a large number of space missions. ZERODUR® was used for the secondary mirror in HST and for the Wolter mirrors in CHANDRA without any reported degradation of the optical image quality during the lifetime of the missions. Some years ago early studies on the compaction effects of electron radiation on ZERODUR® were re analyzed. Using a more relevant physical model based on a simplified bimetallic equation the expected deformation of samples exposed in laboratory and space could be predicted in a much more accurate way. The relevant ingredients for light weighted mirror substrates are discussed in this paper: substrate material with excellent homogeneity in its properties, sufficient bending strengths, space radiation hardness and CNC machining capabilities.
Dilaton minimally coupled to 2 + 1 Einstein Maxwell fields; stationary cyclic symmetric black holes
Garcia-Diaz, A A
2014-01-01
Using the Schwarzschild coordinate frame for a static cyclic symmetric metric in 2 + 1 Einstein gravity coupled to a electric Maxwell field and a dilaton logarithmically depending on the radial coordinate in the presence of an exponential potential the general solution of the Einstein Maxwell dilaton equations is derived and it is identified with the Chan Mann charged dilaton solution. Via a general SL(2;R) transformation, applied on the obtained charged dilaton metric, a family of stationary dilaton solutions has been generated; these solutions possess five parameters: dilaton and cosmological constants , charge, momentum, and mass for some values of them. All the exhibited solutions have been characterized by their quasi-local energy, mass, and momentum through their series expansions at spatial infinity. The structural functions determining these solutions increase as the radial coordinate does, hence they do not exhibit an dS AdS behavior at infinity Moreover, the algebraic structure of the Maxwell field,...
Chen, Yongpin P; Jiang, Li Jun; Meng, Min; Wu, Yu Mao; Chew, Weng Cho
2016-01-01
A novel unified Hamiltonian approach is proposed to solve Maxwell-Schrodinger equation for modeling the interaction between classical electromagnetic (EM) fields and particles. Based on the Hamiltonian of electromagnetics and quantum mechanics, a unified Maxwell-Schrodinger system is derived by the variational principle. The coupled system is well-posed and symplectic, which ensures energy conserving property during the time evolution. However, due to the disparity of wavelengths of EM waves and that of electron waves, a numerical implementation of the finite-difference time-domain (FDTD) method to the multiscale coupled system is extremely challenging. To overcome this difficulty, a reduced eigenmode expansion technique is first applied to represent the wave function of the particle. Then, a set of ordinary differential equations (ODEs) governing the time evolution of the slowly-varying expansion coefficients are derived to replace the original Schrodinger equation. Finally, Maxwell's equations represented b...
Maxwell's equations as a special case of deformation of a solid lattice in Euler's coordinates
Gremaud, G
2016-01-01
It is shown that the set of equations known as Maxwell's equations perfectly describe two very different systems: (1) the usual electromagnetic phenomena in vacuum or in the matter and (2) the deformation of isotropic solid lattices, containing topological defects as dislocations and disclinations, in the case of constant and homogenous expansion. The analogy between these two physical systems is complete, as it is not restricted to one of the two Maxwell's equation couples in the vacuum, but generalized to the two equation couples as well as to the diverse phenomena of dielectric polarization and magnetization of matter, just as to the electrical charges and the electrical currents. The eulerian approach of the solid lattice developed here includes Maxwell's equations as a special case, since it stems from a tensor theory, which is reduced to a vector one by contraction on the tensor indices. Considering the tensor aspect of the eulerian solid lattice deformation theory, the analogy can be extended to other ...
Maxwell's equal area law for black holes with a nonlinear source
Li, Huai-Fan; Zhao, Hui-Hua; Zhao, Ren
2016-01-01
In this paper, we consider the phase transition of black hole in power Maxwell invariant by means of Maxwell's equal area law. First, we review and study the analogy of nonlinear charged black hole solutions with the Van der Waals gas-liquid system in the extended phase space, and obtain isothermal $P$-$v$ diagram. Then, using the Maxwell's equal area law we study the phase transition of AdS black hole with different temperatures. Finally, we extend the method to the black hole in the canonical (grand canonical) ensemble in which charge (potential) is fixed at infinity. Interestingly, we find the phase transition occurs in the both ensembles. We also study the effect of the parameters of the black hole on the two-phase coexistence. The results show that the black hole may go through a small-large phase transition similar to those of usual non-gravity thermodynamic systems.
Effects of backreaction on power-Maxwell holographic superconductors in Gauss-Bonnet gravity
Energy Technology Data Exchange (ETDEWEB)
Salahi, Hamid Reza; Montakhab, Afshin [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Sheykhi, Ahmad [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O. Box 55134-441, Maragha (Iran, Islamic Republic of)
2016-10-15
We analytically and numerically investigate the properties of s-wave holographic superconductors by considering the effects of scalar and gauge fields on the background geometry in five-dimensional Einstein-Gauss-Bonnet gravity. We assume the gauge field to be in the form of the power-Maxwell nonlinear electrodynamics. We employ the Sturm-Liouville eigenvalue problem for analytical calculation of the critical temperature and the shooting method for the numerical investigation. Our numerical and analytical results indicate that higher curvature corrections affect condensation of the holographic superconductors with backreaction. We observe that the backreaction can decrease the critical temperature of the holographic superconductors, while the power-Maxwell electrodynamics and Gauss-Bonnet coefficient term may increase the critical temperature of the holographic superconductors. We find that the critical exponent has the mean-field value β = 1/2, regardless of the values of Gauss-Bonnet coefficient, backreaction and power-Maxwell parameters. (orig.)
The relation between Maxwell, Dirac, and the Seiberg-Witten equations
Directory of Open Access Journals (Sweden)
Waldyr A. Rodrigues
2003-01-01
Full Text Available We discuss unsuspected relations between Maxwell, Dirac, and the Seiberg-Witten equations. First, we present the Maxwell-Dirac equivalence (MDE of the first kind. Crucial to that proposed equivalence is the possibility of solving for ψ (a representative on a given spinorial frame of a Dirac-Hestenes spinor field the equation F=ψγ21ψ˜, where F is a given electromagnetic field. Such task is presented and it permits to clarify some objections to the MDE which claim that no MDE may exist because F has six (real degrees of freedom and ψ has eight (real degrees of freedom. Also, we review the generalized Maxwell equation describing charges and monopoles. The enterprise is worth, even if there is no evidence until now for magnetic monopoles, because there are at least two faithful field equations that have the form of the generalized Maxwell equations. One is the generalized Hertz potential field equation (which we discuss in detail associated with Maxwell theory and the other is a (nonlinear equation (of the generalized Maxwell type satisfied by the 2-form field part of a Dirac-Hestenes spinor field that solves the Dirac-Hestenes equation for a free electron. This is a new result which can also be called MDE of the second kind. Finally, we use the MDE of the first kind together with a reasonable hypothesis to give a derivation of the famous Seiberg-Witten equations on Minkowski spacetime. A physical interpretation for those equations is proposed.
Hubble Space Telescope-Illustration
1989-01-01
This illustration depicts a side view of the Hubble Space Telescope (HST). The HST is the product of a partnership between NASA, European Space Agency Contractors, and the international community of astronomers. It is named after Edwin P. Hubble, an American Astronomer who discovered the expanding nature of the universe and was the first to realize the true nature of galaxies. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The major elements of the HST are the Optical Telescope Assembly (OTA), the Support System Module (SSM), and the Scientific Instruments (SI). The HST is approximately the size of a railroad car, with two cylinders joined together and wrapped in a silvery reflective heat shield blanket. Wing-like solar arrays extend horizontally from each side of these cylinders, and dish-shaped anternas extend above and below the body of the telescope. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.
The Large Binocular Telescope Project
Hill, J. M.
1995-05-01
The Large Binocular Telescope (LBT) Project has evolved from concepts first proposed in 1985. The present partners involved in the design and construction of this 2 x 8.4 meter binocular telescope are the University of Arizona, Italy represented by the Osservatorio Astrofisico di Arcetri and the Research Corporation based in Tucson. These three partners have committed sufficient funds to build the enclosure and the telescope populated with a single 8.4 meter optical train --- approximately 40 million dollars (1989). Based on this commitment, design and construction activities are now moving forward. Additional partners are being sought. The next mirror to be cast at the Steward Observatory Mirror Lab in spring of 1996 will be the first borosilicate honeycomb primary for LBT. The baseline optical configuration of LBT includes wide field Cassegrain secondaries with optical foci above the primaries to provide a corrected one degree field at F/4. The infrared F/15 secondaries are a Gregorian design to allow maximicrons flexibility for adaptive optics. The F/15 secondaries are undersized to provide a low thermal background focal plane which is unvignetted over a 4 arcminute diameter field-of-view. The interferometric focus combining the light from the two 8.4 meter primaries will reimage two folded Gregorian focal planes to a central location. The telescope elevation structure accommodates swing arms which allow rapid interchange of the various secondary and tertiary mirrors. Maximicrons stiffness and minimal thermal disturbance continue to be important drivers for the detailed design of the telescope. The telescope structure accommodates installation of a vacuum bell jar for aluminizing the primary mirrors in-situ on the telescope. The detailed design of the telescope structure will be completed in 1995 by ADS Italia (Lecco) and European Industrial Engineering (Mestre). The final enclosure design is now in progress at M3 Engineering (Tucson) and ADS Italia
BCK Network of Optical Telescopes
McGruder, Charles H.; Antoniuk, Krill; Carini, Michael T.; Gelderman, Richard; Hammond, Benjamin; Hicks, Stacy; Laney, David; Shakhovskoy, David; Strolger, Louis-Gregory; Williams, Joshua
2015-01-01
The BCK network consists of three research grade telescopes: 0.6m (B) at the Bell Observatory near Western Kentucky University (WKU), 1.3m (C) at the Crimean Astrophysical Observatory and a 1.3m (K) at Kitt Peak National Observatory. The Bell Telescope is operated remotely from WKU while the Robotically Controlled Telescope (RCT) at Kitt Peak possesses an autonomous scheduler. The BCK telescopes are distributed longitudinally over 145º and can be used to observe continuously up to 21.2 hours/day. The network will be chiefly employed to observe variable stars, blazars and unpredictable celestial events.Because celestial objects with ground-based telescopes cannot be observed optically during the daytime, continuous ground-based astronomical observations are only possible via a network of longitudinally distributed telescopes. When the sun rises in Crimea after it sets at Bell, continuous observations are possible. This occurs for about six and ½ months per year - mid September to early April. A network is highly desirable for events that are not predictable for instance the appearance of supernovae, gamma-ray bursts, or undiscovered exoplanetsVariable stars are really only known in significant numbers to about 14 mag. But, as the magnitude increases the number of stars in any field increases very sharply, so there are many variable stars to discover at faint magnitude (m > 14). Discovering new variables makes great undergraduate student projects, a major component of astronomical research at WKU. In addition, pinning down the periods of variable stars is greatly facilitated with a network of telescopes.The BCK telescope network will also be used for monitoring the optical variability of blazars. The network provides increased coverage on daily variability timescales by minimizing interruptions due to weather and or mechanical problems at any one observatory and is used for obtaining continuous (12+ hours) of observations of rapid variability in blazars which would
Quasi-local conserved charges in the Einstein-Maxwell theory
Setare, M R
2016-01-01
In this paper we consider the Einstein-Maxwell theory and define a combined transformation composed of diffeomorphism and $U(1)$ gauge transformation. For generality, we assume that the generator $\\chi$ of such transformation is field dependent. We define the extended off-shell ADT current and then off-shell ADT charge such that they are conserved off-shell for asymptotically field dependent symmetry generator $\\chi$. Consequently, we define conserved charge corresponds to asymptotically field dependent symmetry generator $\\chi$. We apply the presented method to find conserved charges of asymptotically AdS$_{3}$ spacetimes in the context of the Einstein-Maxwell theory in three dimensions.
On the Equivalence of the Massless DKP equation and the Maxwell Equations in the Shuwer
Salti, M; Salti, Mustafa; Havare, Ali
2005-01-01
In this paper, a general relativistic wave equation is written to deal with electromagnetic waves in the background of the Shuwer. We obtain the exact form of this equation in a second order form. On the other hand, by using spinor form of the Maxwell equations the propagation problem is reduced to the solution of the second order differential equation of complex combination of the electric and magnetic fields. For these two different approach, we obtain the spinors in terms of field strength tensor. We show that the Maxwell equations are the equivalence with the mDKP equation in the Shuwer.
Static Einstein-Maxwell Black Holes with No Spatial Isometries in AdS Space
Herdeiro, Carlos A. R.; Radu, Eugen
2016-11-01
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.
Multivariate and matrix-variate analogues of Maxwell-Boltzmann and Raleigh densities
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.
Maxwell-Chern-Simons theory and an ambiguity in Chern-Simons perturbation theory
Energy Technology Data Exchange (ETDEWEB)
Leblanc, M.; Thomaz, M.T. (Center for Theoretical Physics, Lab. for Nuclear Science, Dept. of Physics, Massachusetts Inst. of Technology, Cambridge, MA (United States))
1992-05-14
We calculate the one-loop effective potential for a matter scalar field in the N=2 supersymmetric Maxwell-Chern-Simons model. It is found that the degeneracy of the classical potential is not lifted by radiative corrections. We show that reduction to the effective potential for the Chern-Simons theory as a limit from the Maxwell-Chern-Simons theory gives rise at one loop to an expression that differs from the result obtained solely within Chern-Simons theory. (orig.).
Unsteady flow of viscoelastic fluid between two cylinders using fractional Maxwell model
Institute of Scientific and Technical Information of China (English)
Muhammad Jamil; Constantin Fetecau; Corina Fetecau
2012-01-01
The unsteady flow of an incompressible fractional Maxwell fluid between two infinite coaxial cylinders is studied by means of integral transforms.The motion of the fluid is due to the inner cylinder that applies a time dependent torsional shear to the fluid.The exact solutions for velocity and shear stress are presented in series form in terms of some generalized functions.They can easily be particularized to give similar solutions for Maxwell and Newtonian fluids.Finally,the influence of pertinent parameters on the fluid motion,as well as a comparison between models,is highlighted by graphical illustrations.
Sobre el teorema de Maxwell y la optimización de arcos de cubierta
Directory of Open Access Journals (Sweden)
Quintas Ripoll, Valentín
1989-04-01
Full Text Available Optimal shapes of arches can be deduced from a theorem developed by Maxwell. In this paper optimal shapes of various types of arches are obtained, when loads are of equal magnitude.
Aplicando un teorema enunciado por Maxwell, se pueden obtener las formas de mínimo material para arcos que soportan cargas iguales, trabajando exclusivamente a tracción o compresión. En este artículo se obtienen las formas óptimas para varios tipos de arcos y se propone un método de diseño mínimo.
Static Einstein-Maxwell Black Holes with No Spatial Isometries in AdS Space.
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.
The Maxwell-Einstein system, Ward identities and the Vilkovisky construction
DEFF Research Database (Denmark)
Nielsen, N. K.
2012-01-01
The gauge fixing dependence of the one-loop effective action of quantum gravity in the proper-time representation is investigated for a space of arbitrary curvature, and the investigation is extended to Maxwell-Einstein theory. The construction of Vilkovisky and DeWitt for removal of this depende......The gauge fixing dependence of the one-loop effective action of quantum gravity in the proper-time representation is investigated for a space of arbitrary curvature, and the investigation is extended to Maxwell-Einstein theory. The construction of Vilkovisky and DeWitt for removal...
Kisel, V V; Red'kov, V M; Tokarevskaya, N G
2009-01-01
The Riemann -- Silberstein -- Majorana -- Oppenheimer approach to the Maxwell electrodynamics in vacuum is investigated within the matrix formalism. The matrix form of electrodynamics includes three real 4 \\times 4 matrices. Within the squaring procedure we construct four formal solutions of the Maxwell equations on the base of scalar Klein -- Fock -- Gordon solutions. The problem of separating physical electromagnetic waves in the linear space \\lambda_{0}\\Psi^{0}+\\lambda_{1}\\Psi^{1}+\\lambda_{2}\\Psi^{2}+ lambda_{3}\\Psi^{3} is investigated, several particular cases, plane waves and cylindrical waves, are considered in detail.
DEFF Research Database (Denmark)
Pessah, Martin Elias; Chan, Chi-kwan; Psaltis, Dimitrios
2006-01-01
The magnetorotational instability is thought to be responsible for the generation of magnetohydrodynamic turbulence that leads to enhanced outward angular momentum transport in accretion discs. Here, we present the first formal analytical proof showing that, during the exponential growth...... of the instability, the mean (averaged over the disc scale-height) Reynolds stress is always positive, the mean Maxwell stress is always negative, and hence the mean total stress is positive and leads to a net outward flux of angular momentum. More importantly, we show that the ratio of the Maxwell to the Reynolds...
Mimetic discretizations for Maxwell equations and the equations of magnetic diffusion
Energy Technology Data Exchange (ETDEWEB)
Hyman, J.M.; Shashkov, M.
1998-03-01
The authors construct reliable finite difference methods for approximating the solutions Maxwell`s equations and equations of magnetic field diffusion using discrete analogs of differential operators that satisfy the identities and theorems of vector and tensor calculus in discrete form. These methods mimic many fundamental properties of the underlying physical problem including the conservation laws, the symmetries in the solution, the nondivergence of particular vector fields and they do not have spurious modes. The constructed method can be applied in case of strongly discontinuous properties of the media for nonorthogonal and nonsmooth computational grids.
Nonminimally coupled Einstein-Maxwell model in a non-Riemann spacetime with torsion
2015-01-01
Nonminimally coupled Einstein-Maxwell model in a non-Riemann spacetime with torsion Ahmet Baykal* Department of Physics, Faculty of Arts and Sciences, Niğde University, Bor Yolu 51240 Niğde, Turkey Tekin Dereli† Department of Physics, College of Science, Koç University, Rumelifeneri Yolu, 34450 Sarıyer, İstanbul, Turkey (Received 25 May 2015; published 22 September 2015) A system of field equations for an Einstein-Maxwell model with RF2-type nonminimal coupling in a ...
Hamiltonian particle-in-cell methods for Vlasov-Maxwell equations
He, Yang; Qin, Hong; Liu, Jian
2016-01-01
In this paper, we develop Hamiltonian particle-in-cell methods for Vlasov-Maxwell equations by applying conforming finite element methods in space and splitting methods in time. For the spatial discretisation, the criteria for choosing finite element spaces are presented such that the semi-discrete system possesses a discrete non-canonical Poisson structure. We apply a Hamiltonian splitting method to the semi-discrete system in time, then the resulting algorithm is Poisson preserving and explicit. The conservative properties of the algorithm guarantee the efficient and accurate numerical simulation of the Vlasov-Maxwell equations over long-time.
Dual Role of Viscosity During Start-Up of a Maxwell Fluid in a Pipe
Institute of Scientific and Technical Information of China (English)
任玲; 朱克勤
2004-01-01
Based on the exact solution of start-up flow of Maxwell fluids in a long circular straight pipe, the effect of viscosity on the time of flow establishment is analysed. It is found that the viscosity of Maxwell fluids plays a dual role.A key parameter is the dimensionless relaxation time λ-. For 0 ＜λ-＜ 0.0432, the viscosity mainly plays the same role as in Newtonian fluids, and the time of flow establishment decreases with the increasing viscosity; for λ- ＞ 0.0432, the viscosity mainly plays a role of strengthening the oscillation, and the time of flow establishment increases with the incremental viscosity.
SLAS Library Telescope Program (Abstract)
Small, J. S.
2016-12-01
(Abstract only) In the fall of 2014, I submitted to the members of the St. Louis Astronomical Society to take the $1,000 profit we had from a convention we had hosted and use it to purchase three telescopes to modify for a Library Telescope program that was invented by Mark Stowbridge and promoted by the New Hampshire Astronomical Society. I had met Mark at NEAF in 2012 when he was walking the floor demonstrating the telescope. We held meetings with three libraries, the St. Louis County Library system, the St. Louis Public Library system and an independent library in Kirkwood, Missouri. The response was overwhelming! SLCL responded with a request for ten telescopes and SLPL asked for five. We did our first build in October, 2014 and placed a total of eighteen telescopes. Since that time, SLAS has placed a total of eighty-eight telescopes in library systems around the St. Louis Metro area, expanding into neighboring counties and across the river in Illinois. In this talk, I will discuss how to approach this project and put it in place in your libraries!
Concept Design for SOAR Telescope
Sebring, T.; Cecil, G.; Krabbendam, V.; Moretto, G.
1998-12-01
The Southern Astrophysical Research (SOAR) telescope is a \\$28M collaboration between Brazil, NOAO, Michigan State University, and the University of North Carolina at Chapel Hill. NOAO will operate the telescope for 20 years in exchange for 30 astronomers.) The project is now fully funded. This f/16 telescope is optimized for high-quality images across the isokinetic field (0."17 FWHM degradation from the telescope+facility over a field of 7.5' diameter.) It is being designed to take up to 2 Gemini-class (2100 kg) instruments, or a combination of lighter instruments at 7 Nasmyth and bent Cassegrain foci. The facility is now under construction atop Cerro Pachon, 400m from Gemini-S. First light is currently scheduled for early 2002. Corning Inc. is preparing to fabricate the 4.2m-diameter, 7.5-10 cm thick primary mirror from ULE glass. In early 1999 contacts will be awarded for 2 major subsystems: active optics (which includes optics polishing), and the alt.-az. telescope mount. We will outline the novel strategies that are being used to control project costs while optimizing telescope performance. Instrumentation plans will also be summarized.
The upgraded MAGIC Cherenkov telescopes
Energy Technology Data Exchange (ETDEWEB)
Tescaro, D., E-mail: dtescaro@iac.es [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Universidad de La Laguna (ULL), Dept. Astrofísica, E-38206 La Laguna, Tenerife (Spain)
2014-12-01
The MAGIC Cherenkov telescopes underwent a major upgrade in 2011 and 2012. A new 1039-pixel camera and a larger area digital trigger system were installed in MAGIC-I, making it essentially identical to the newer MAGIC-II telescope. The readout systems of both telescopes were also upgraded, with fully programmable receiver boards and DRS4-chip-based digitization systems. The upgrade eased the operation and maintenance of the telescopes and also improved significantly their performance. The system has now an integral sensitivity as good as 0.6% of the Crab Nebula flux (for E>400GeV), with an effective analysis threshold at 70 GeV. This allows MAGIC to secure one of the leading roles among the current major ground-based Imaging Atmospheric Cherenkov telescopes for the next 5–10 years. - Highlights: • In 2011 and 2012 the MAGIC telescopes underwent a two-stage major upgrade. • The new camera of MAGIC-I allows us to exploit a 1.4 larger trigger area. • The novel DRS4-based readout systems allow a cost-effective ultra-fast digitization. • The upgrade greatly improved the maintainability of the system. • MAGIC has now an optimal integral sensitivity of 0.6% of the Crab Nebula flux.
Demonstration Telescopes Using "Dollar Optics"
Ross, Paul
2008-05-01
I propose a poster that illustrates the use of "dollar optics” for experimentation and for the creation of demonstration telescopes. Handling a variety of lenses and mirrors provides an opportunity for discovering practical optics. Some part of this path of exploration must have been traveled by Galileo as he experimented with spectacle lenses. "Dollar optics” include reading glasses (positive meniscus lenses), convex and concave mirrors, Fresnel sheets, magnifying lenses, and eye loupes. Unwanted distance spectacles (negative meniscus lenses) are available at second-hand stores. Galileo telescopes, "long” 17th century telescopes, and useful demonstration models of Newtonian reflectors can be made with "dollar” optics. The poster will illustrate practical information about "dollar optics” and telescopes: magnification, focal length, and "diopters” disassembling spectacles; creating cheap mounts for spectacle lenses; the importance of optical axes and alignment; eyepieces; and focusing. (A table would be useful with the poster to set out a hands-on display of "dollar optic” telescopes.) Educators, experimenters, and those concerned with astronomy outreach might be interested in this poster. Working with "dollar optics” requires facility with simple tools, interest in planning projects, patience, imagination, and the willingness to invest some time and effort. "Dollar optics” may help to foster creativity and hands-on enthusiasm - as did Galileo's work with simple lenses 400 years ago. "Oh! When will there be an end put to the new observations and discoveries of this admirable instrument?” - Galileo Galilei as quoted by Henry C. King, The History of the Telescope.
Searching for Correlations with the HCO+ 4-3 Molecular Spectra of Protostars
Acikgoz, Ogulcan; Basturk, Seda
The assignment is based on HCO+ J=4-3 spectral line molecular observations of protostars from the James Clerk Maxwell Telescope, which has the 15 m diameter dish and located in Mauna Kea, Hawaii, USA. Data of 20 protostars are taken from the public LOMASS database and analyzed. We looked for correlations between a few observational quantities. We thank Dr Umut Yildiz (NASA/JPL-Caltech) for providing data and his comments and support to our research project.
The Research Productivity of Small Telescopes and Space Telescopes
Ringwald, F A; Lovell, R L; Kays, S A; Torres, Y V A
2003-01-01
We present statistics on the research productivity of astronomical telescopes. These were compiled by finding papers in which new data were presented, noting which telescopes were used, and then counting the number of papers, number of pages, and other statistics. The journals used were the Astronomical Journal, the Astrophysical Journal (including the Letters and Supplements), and the Publications of the Astronomical Society of the Pacific. We also compiled citations from the Science Citation Index. This work was designed to be similar to that of Trimble (1995), except that more recent journals (from 1995) and citations (from 1998) were used. We also did not restrict our sample to large telescopes only: we included all telescopes from which new data were presented, the smallest of which was a 0.1-m. The data were gathered by first-year work-study undergraduates, who were instructed to include data for all telescopes for which they found new data were included in the journals. A by-product of this research wa...
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...
Entropy Generation by a Maxwell Demon in the Sequential Sorting of the Particles in an Ideal Gas
Jones, Roger D.; Sven G. Redsun; Frye, Roger E.
2003-01-01
This paper revisits the Maxwell Demon Problem. Representing the demon with a simple physical computer composed of a single memory element, we demonstrate that the average minimum entropy increase of the universe due to sorting of particles with a Maxwell Demon is eta=0.8400 for particles that are initially randomly distributed.
Schwarzschild-Couder Telescope for the Cherenkov Telescope Array
Meagher, Kevin J
2014-01-01
The Cherenkov Telescope Array (CTA) is the next major ground-based observatory for gamma-ray astronomy. With CTA gamma-ray sources will be studied in the very-high energy gamma-ray range of a few tens of GeV to 100 TeV with up to ten times better sensitivity than available with current generation instruments. We discuss the proposed US contribution to CTA that comprises imaging atmospheric Cherenkov telescope with Schwarzschild-Couder (SC) optics. Key features of the SC telescope are a wide field of view of eight degrees, a finely pixelated camera with silicon photomultipliers as photon detectors, and a compact and power efficient 1 GS/s readout. The progress in both the optical system and camera development are discussed in this paper.
Maxwell equation violation by density dependent magnetic fields in neutron stars
Menezes, Débora P
2016-01-01
We show that the widely used density dependent magnetic field prescriptions, necessary to account for the variation of the field intensity from the crust to the core of neutron stars violate one of the Maxwell equations. We estimate how strong the violation is when different equations of state are used and check for which cases the pathological problem can be cured.
Time-integration methods for finite element discretisations of the second-order Maxwell equation
Sármány, D.; Botchev, M.A.; Vegt, van der J.J.W.
2012-01-01
This article deals with time integration for the second-order Maxwell equations with possibly non-zero conductivity in the context of the discontinuous Galerkin finite element method DG-FEM) and the $H(\\mathrm{curl})$-conforming FEM. For the spatial discretisation, hierarchic $H(\\mathrm{curl})$-conf
A Nonconforming Arbitrary Quadrilateral Finite Element Method for Approximating Maxwell's Equations
Institute of Scientific and Technical Information of China (English)
Dongyang Shi; Lifang Pei; Shaochun Chen
2007-01-01
The main aim of this paper is to provide convergence analysis of Quasi-Wilson nonconforming finite element to Maxwell's equations under arbitrary quadrilateral meshes. The error estimates are derived, which are the same as those for conforming elements under conventional regular meshes.
New Unconditionally Stable Algorithms to Solve the Time-Dependent Maxwell Equations
Kole, J.S.; Figge, M.T.; Raedt, H. De
2002-01-01
We present a family of unconditionally stable algorithms, based on the Suzuki product-formula approach, that solve the time-dependent Maxwell equations in systems with spatially varying permittivity and permeability. Salient features of these algorithms are illustrated by computing the density of st
Regularity of the Maxwell equations in heterogeneous media and Lipschitz domains
Bonito, Andrea
2013-12-01
This note establishes regularity estimates for the solution of the Maxwell equations in Lipschitz domains with non-smooth coefficients and minimal regularity assumptions. The argumentation relies on elliptic regularity estimates for the Poisson problem with non-smooth coefficients. © 2013 Elsevier Ltd.
The Space-Time CE/SE Method for Solving Maxwell's Equations in Time-Domain
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.
Analysis of a Three Phase Induction Motor Directly from Maxwell's Equations
Bhattacharjee, Shayak
2011-01-01
The torque developed in a three phase AC squirrel cage motor is usually expressed in terms of resistances and reactances of the stator, the rotor, and the motor as a whole. We use Maxwell's equations to find the torque in terms of geometrical parameters. This allows us to estimate the torque developed by a motor without knowing the details of its circuitry.
Institute of Scientific and Technical Information of China (English)
Haitao Qi; Hui Jin
2006-01-01
The fractional calculus is used in the constitutive relationship model of viscoelastic fluid.A generalized Maxwell model with fractional calculus is considered.Based on the flow conditions described,two flow cases are solved and the exact solutions are obtained by using the Weber transform and the Laplace transform for fractional calculus.
A first-class approach of higher derivative Maxwell-Chern-Simons-Proca model
Energy Technology Data Exchange (ETDEWEB)
Sararu, Silviu-Constantin [University of Craiova, Department of Physics, Craiova (Romania)
2015-11-15
The equivalence between a higher derivative extension of Maxwell-Chern-Simons-Proca model and some gauge invariant theories from the point of view of the Hamiltonian path integral quantization in the framework of the gauge-unfixing approach is investigated. The Hamiltonian path integrals of the first-class systems take manifestly Lorentz-covariant forms. (orig.)
Can Maxwell's Fish Eye Lens Really Give Perfect Imaging? Part II. The case with drains
Sun, Fei; He, Sailing
2010-01-01
We use both FEM (finite element method) and FDTD (finite difference time domain method) to simulate the field distribution in Maxwell's fish eye lens with one or more passive drains around the image point. We use the same Maxwell's fish eye lens structure as the one used in recent microwave experiment [arXiv:1007.2530]: Maxwell's fish eye lens bounded by PEC (perfect electric conductor) is inserted between two parallel PEC plates (as a waveguide structure). Our simulation results indicate that if one uses an active coaxial cable as the object and set an array of passive drains around the image region, what one obtains is not an image of the object but only multiple spots resembling the array of passive drains. The resolution of Maxwell's fish eye is finite even with such passive drains at the image locations. We also found that the subwavelength spot around the passive drain is due to the local field enhancement of the metal tip of the drain rather than the fish eye medium or the ability of the drain in extra...
Study on internal structure of Maxwell-Gauss-Bonnet black hole
Energy Technology Data Exchange (ETDEWEB)
Rannu, K A; Alexeyev, S O [Sternberg Astronomical Institute, Lomonosov Moscow State University, Universitetsy Prospect, 13, Moscow 119991 (Russian Federation); Barrau, A, E-mail: rannu@xray.sai.msu.r [Laboratoire de Physique Subatomique et de Cosmologie, UJF-INPG-CNRS, 53, avenue des Martyrs, 38026 Grenoble cedex (France)
2010-05-01
The influence of the Maxwell field on a static, asymptotically flat and spherically-symmetric Gauss-Bonnet black hole is considered. Numerical computations suggest that if the charge increases beyond a critical value, the inner determinant singularity is replaced by an inner singular horizon.
Least-Squares Approaches for the Time-Dependent Maxwell Equations
Energy Technology Data Exchange (ETDEWEB)
Zhiquiang, C; Jones, J
2001-12-01
When the author was at CASC in LLNL during the period between July and December of last year, he was working on two research topics: (1) least-squares approaches for elasticity and Maxwell equations and (2) high-accuracy approximations for non-smooth problems.
Photonic crystal fibres: mapping Maxwell's equations onto a Schrödinger equation eigenvalue problem
DEFF Research Database (Denmark)
Mortensen, Niels Asger
2006-01-01
We consider photonic crystal fibres (PCFs) made from arbitrary base materials and introduce a short-wavelength approximation which allows for a mapping of the Maxwell's equations onto a dimensionless eigenvalue equations which has the form of the Schröding equation in quantum mechanics. The mappi...
On the energy conservation by weak solutions of the relativistic Vlasov-Maxwell system
Sospedra-Alfonso, Reinel
2010-01-01
We show that weak solutions of the relativistic Vlasov-Maxwell system preserve the total energy provided that the electromagnetic field is locally of bounded variation and, for any $\\lambda$> 0, the one-particle distribution function has a square integrable $\\lambda$-moment in the momentum variable.
An Exact Solution to the Two-Particle Boltzmann Equation System for Maxwell Gases
Institute of Scientific and Technical Information of China (English)
布仁满都拉; 赵迎春
2012-01-01
An exact solution to the two-particle Boltzmann equation system for Maxwell gases is obtained with use of Bobylev approach.The relationship between the exact solution and the self-similar solution of the boltzmann equation is also given.
A short guide to exponential Krylov subspace time integration for Maxwell's equations
Botchev, Mike A.
2012-01-01
The exponential time integration, i.e., time integration which involves the matrix exponential, is an attractive tool for solving Maxwell's equations in time. However, its application in practice often requires a substantial knowledge of numerical linear algebra algorithms, in particular, of the Kry
Bonito, Andrea
2011-01-01
We propose and analyze an approximation technique for the Maxwell eigenvalue problem using H1-conforming finite elements. The key idea consists of considering a mixed method controlling the divergence of the electric field in a fractional Sobolev space H-α with α ∈ (1/2, 1). The method is shown to be convergent and spectrally correct. © 2011 American Mathematical Society.
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,...
Simple Derivation of the Maxwell Stress Tensor and Electrostrictive Effects in Crystals
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)
Unified framework for numerical methods to solve the time-dependent Maxwell equations
De Raedt, H; Kole, JS; Michielsen, KFL; Figge, MT
2003-01-01
We present a comparative study of numerical algorithms to solve the time-dependent Maxwell equations for systems with spatially varying permittivity and permeability. We show that the Lie-Trotter-Suzuki product-formula approach can be used to construct a family of unconditionally stable algorithms,
Review article number 50 - The Maxwell-Stefan approach to mass transfer
Krishna, R.; Wesselingh, J.A
1997-01-01
The limitations of the Fick's law for describing diffusion are discussed. It is argued that the Maxwell-Stefan formulation provides the most general, and convenient, approach for describing mass transport which takes proper account of thermodynamic non-idealities and influence of external force fiel
Robustness of the nonequilibrium entropy related to the Maxwell-Cattaneo heat equation
Àlvarez Calafell, Francesc Xavier
2008-01-01
The connection between the Maxwell-Cattaneo heat transport equation and a nonequilibrium entropy is examined through four different thermodynamic approaches, and it is shown that all of them lead to the same form of the nonequilibrium entropy. Furthermore, it is seen that this form is also consistent with three microscopic formalisms. This robustness underlines the consistency and relevance of the entropy.
Quantum tunnelling radiation of Einstein-Maxwell-Dilaton-Axion black hole
Institute of Scientific and Technical Information of China (English)
Yang Shu-Zheng; Jiang Qing-Quan; Li Hui-Ling
2005-01-01
By taking the energy conservation and angular momentum conservation into account, the characteristics of the quantum-tunnelling radiation of Einstein-Maxwell-Dilaton-Axion black hole are studied and the result shows that the tunnelling rate of such a black hole is relevant to Bekenstein-Hawking entropy and that the obtained radiation spectrum is not pure thermal.
Analytical and Numerical Study of Gauss-Bonnet Holographic Superconductors with Power-Maxwell Field
Sheykhi, A; Montakhab, Afshin
2016-01-01
We provide an analytical as well as a numerical study of the holographic $s$-wave superconductors in Gauss-Bonnet gravity with Power-Maxwell electrodynamics. We limit our study to the case where scalar and gauge fields do not have n effect on the background metric. We use a variational method, based on Sturm-Liouville eigenvalue problem for our analytical study, as well as a numerical shoting method in order to compare with our analytical results. Interestingly enough, we observe that unlike Born-Infeld-like nonlinear electrodynamics which decrease the critical temperature compared to the linear Maxwell field, the Power-Maxwell electrodynamics is able to increase the critical temperature of the holographic superconductors in the sublinear regime. We find that requiring the finite value for the gauge field on the asymptotic boundary $r\\rightarrow \\infty$, restricts the power parameter, $q$, of the Power-Maxwell field to be in the range $1/2
The square root of the Dirac operator on the superspace and the Maxwell equations
Bzdak, A; Bzdak, Adam; Hadasz, Leszek
2003-01-01
We re-consider the procedure of ``taking a square root of the Dirac equation'' on the superspace and show that it leads to the well known superfield W_\\alpha and to the proper equations of motion for the components, i.e. the Maxwell equations and the massless Dirac equation.
The square root of the Dirac operator on superspace and the Maxwell equations
Energy Technology Data Exchange (ETDEWEB)
Bzdak, Adam; Hadasz, Leszek
2004-02-26
We re-consider the procedure of 'taking a square root of the Dirac equation' on superspace and show that it leads to the well-known superfield W{sub {alpha}} and to the proper equations of motion for the components, i.e., the Maxwell equations and the massless Dirac equation.
On Bianchi-I cosmic strings coupled with Maxwell ﬁelds in bimetric relativity
Indian Academy of Sciences (India)
V Mahurpawar; S D Deo
2003-10-01
Axially symmetric Bianchi-I model is studied with source cosmic cloud strings coupled with electromagnetic ﬁeld in Rosen’s bimetric theory of relativity and observed that there is no contribution from cosmic strings and Maxwell ﬁelds in this theory.
The Maxwell-Stefan description of mixture diffusion in nanoporous crystalline materials
Krishna, R.
2014-01-01
The efficacy of nanoporous crystalline materials in separation applications is often influenced to a significant extent by diffusion of guest molecules within the pores of the structural frameworks. The Maxwell-Stefan (M-S) equations provide a fundamental and convenient description of mixture diffus
Rauscher, Elizabeth A
2011-01-01
The Maxwell, Einstein, Schrödinger and Dirac equations are considered the most important equations in all of physics. This volume aims to provide new eight- and twelve-dimensional complex solutions to these equations for the first time in order to reveal
FAMOUS. The fluorescence telescope prototype
Energy Technology Data Exchange (ETDEWEB)
Schumacher, Johannes; Bretz, Thomas; Hebbeker, Thomas; Lauscher, Markus; Middendorf, Lukas; Niggemann, Tim; Peters, Christine; Sommer, Dominik; Stephan, Maurice [III. Physikalisches Institut A, RWTH Aachen University (Germany); Auffenberg, Jan; Schaufel, Merlin [III. Physikalisches Institut B, RWTH Aachen University (Germany)
2015-07-01
One of the most successful techniques for the detection of air showers produced by ultra-high-energy cosmic rays are fluorescence telescopes. The light produced by de-exciting nitrogen in the atmosphere is typically detected by photomultiplier tubes (PMTs). This technique has been successfully used by the Pierre Auger Observatory in Argentina for many years. Silicon photomultipliers (SiPMs) promise higher photon detection efficiencies than PMTs. This and other advantages motivate the construction of the fluorescence telescope prototype FAMOUS (First Auger Multi-pixel photon counter camera for the Observation of Ultra-high-energy air Showers) which makes use of SiPMs. In this talk we discuss the FAMOUS telescope with a new 64-pixel camera including power supply and DAQ.
Scientific management of Space Telescope
Odell, C. R.
1981-01-01
A historical summay is given on the science management of the Space Telescope, the inception of which began in 1962, when scientists and engineers first recommended the development of a nearly diffraction limited substantial-size optical telescope. Phase A, the feasibility requirements generation phase, began in 1971 and consisted largely of NASA scientists and a NASA design. Phase B, the preliminary design phase, established a tiered structure of scientists, led by the Large Space Telescope operations and Management Work Group. A Mission Operations Working Group headed six instrument definition teams to develop the essential instrument definitions. Many changes took place during Phase B, before design and development, which began in 1978 and still continues today.
Feature-based telescope scheduler
Naghib, Elahesadat; Vanderbei, Robert J.; Stubbs, Christopher
2016-07-01
Feature-based Scheduler offers a sequencing strategy for ground-based telescopes. This scheduler is designed in the framework of Markovian Decision Process (MDP), and consists of a sub-linear online controller, and an offline supervisory control-optimizer. Online control law is computed at the moment of decision for the next visit, and the supervisory optimizer trains the controller by simulation data. Choice of the Differential Evolution (DE) optimizer, and introducing a reduced state space of the telescope system, offer an efficient and parallelizable optimization algorithm. In this study, we applied the proposed scheduler to the problem of Large Synoptic Survey Telescope (LSST). Preliminary results for a simplified model of LSST is promising in terms of both optimality, and computational cost.
LSST telescope and site status
Gressler, William J.
2016-07-01
The Large Synoptic Survey Telescope (LSST) Project1 received its construction authorization from the National Science Foundation in August 2014. The Telescope and Site (T and S) group has made considerable progress towards completion in subsystems required to support the scope of the LSST science mission. The LSST goal is to conduct a wide, fast, deep survey via a 3-mirror wide field of view optical design, a 3.2-Gpixel camera, and an automated data processing system. The summit facility is currently under construction on Cerro Pachón in Chile, with major vendor subsystem deliveries and integration planned over the next several years. This paper summarizes the status of the activities of the T and S group, tasked with design, analysis, and construction of the summit and base facilities and infrastructure necessary to control the survey, capture the light, and calibrate the data. All major telescope work package procurements have been awarded to vendors and are in varying stages of design and fabrication maturity and completion. The unique M1M3 primary/tertiary mirror polishing effort is completed and the mirror now resides in storage waiting future testing. Significant progress has been achieved on all the major telescope subsystems including the summit facility, telescope mount assembly, dome, hexapod and rotator systems, coating plant, base facility, and the calibration telescope. In parallel, in-house efforts including the software needed to control the observatory such as the scheduler and the active optics control, have also seen substantial advancement. The progress and status of these subsystems and future LSST plans during this construction phase are presented.
Superconductor lunar telescopes --Abstract only
Chen, P. C.; Pitts, R.; Shore, S.; Oliversen, R.; Stolarik, J.; Segal, K.; Hojaji, H.
1994-01-01
We propose a new type of telescope designed specifically for the lunar environment of high vacuum and low temperature. Large area UV-Visible-IR telescope arrays can be built with ultra-light-weight replica optics. High T(sub c) superconductors provide support, steering, and positioning. Advantages of this approach are light-weight payload compatible with existing launch vehicles, configurable large area optical arrays, no excavation or heavy construction, and frictionless electronically controlled mechanisms. We have built a prototype and will be demonstarting some of its working characteristics.
Autonomous Dome for Robotic Telescope
Kumar, Akash; Ganesh, Shashikiran
2016-01-01
Physical Research Laboratory operates a 50cm robotic observatory at Mount Abu. This Automated Telescope for Variability Studies (ATVS) makes use of Remote Telescope System 2 (RTS2) for autonomous operations. The observatory uses a 3.5m dome from Sirius Observatories. We have developed electronics using Arduino electronic circuit boards with home grown logic and software to control the dome operations. We are in the process of completing the drivers to link our Arduino based dome controller with RTS2. This document is a short description of the various phases of the development and their integration to achieve the required objective.
Telescoping phenomenon in pathological gambling
DEFF Research Database (Denmark)
Grant, Jon E; Odlaug, Brian Lawrence; Mooney, Marc E
2012-01-01
The course of pathological gambling (PG) in women has been described as having a later age of initiation but a shorter time to problematic gambling ("telescoped"). This study examined evidence for telescoping and its relationship with comorbidities. Seventy-one treatment-seeking individuals with PG...... underwent a diagnostic interview to examine gambling behaviors, age at initiation of gambling, and time from initiation to meeting criteria for PG. The women had a higher mean age at gambling initiation compared with that of the men (mean [SD] age, 31.3 [13.0] years, compared with 22.4 [7.9] years; p = 0...
Highlights from the Telescope Array
Matthews, J. N.
2016-11-01
The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth's surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.
Energy Technology Data Exchange (ETDEWEB)
Ackermann, Mark R. (Albuquerque, NM); McGraw, John T. (Placitas, NM); Zimmer, Peter C. (Albuquerque, NM)
2008-01-15
A wide field of view telescope having two concave and two convex reflective surfaces, each with an aspheric surface contour, has a flat focal plane array. Each of the primary, secondary, tertiary, and quaternary reflective surfaces are rotationally symmetric about the optical axis. The combination of the reflective surfaces results in a wide field of view in the range of approximately 3.8.degree. to approximately 6.5.degree.. The length of the telescope along the optical axis is approximately equal to or less than the diameter of the largest of the reflective surfaces.
Apollo Telescope Mount Spar Assembly
1969-01-01
The Apollo Telescope Mount (ATM), designed and developed by the Marshall Space Flight Center, served as the primary scientific instrument unit aboard the Skylab. The ATM contained eight complex astronomical instruments designed to observe the Sun over a wide spectrum from visible light to x-rays. This image shows the ATM spar assembly. All solar telescopes, the fine Sun sensors, and some auxiliary systems are mounted on the spar, a cruciform lightweight perforated metal mounting panel that divides the 10-foot long canister lengthwise into four equal compartments. The spar assembly was nested inside a cylindrical canister that fit into the rack, a complex frame, and was protected by the solar shield.
The network of INTA telescopes
Cuesta, L.
2008-06-01
The Spanish Instituto Nacional de Técnica Aeroespacial has a network of three telescopes located at some of the best places for astronomy in mainland Spain. The first is at the Observatorio de Calar Alto in Almeria, at an altitude of more than 2100 m. The second is near Calatayud in Zaragoza, at the summit of a 1400-m high mountain. The last is on the campus of the Instituto Nacional de Técnica Aerospatial (INTA), in Madrid. The three telescopes are either 40 or 50 cm in diameter and will be available for communications and educational projects.
Monster telescope hunts blue planets
Leake, J
2003-01-01
BRITAIN is to back a project to build the world's biggest telescope - so powerful that it could see life-bearing planets in other solar systems. It will need the largest mirror ever built at about 100 metres in diameter (1/2 page).
Teets, Donald
2012-01-01
Two coordinate systems are related here, one defined by the earth's equator and north pole, the other by the orientation of a telescope at some location on the surface of the earth. Applying an interesting though somewhat obscure property of orthogonal matrices and using the cross-product simplifies this relationship, revealing that a surprisingly…
NESTOR Neutrino Telescope Status Report
Grieder, P. K. F.; NESTOR Collaboration; Aloupis, A.; Anassontzis, E. G.; Arvanitis, N.; Babalis, A.; Ball, A.; Bourlis, G.; Butkevich, A. V.; Chinowsky, W.; Christopoulos, P. E.; Darsaklis, A.; Dedenko, L. G.; Elistrup, D.; Fahrun, E.; Gialis, J.; Goudis, Ch.; Grammatikakis, G.; Green, C.; Karaevsky, S. K.; Katrivanos, P.; Keussen, U.; Kiskiras, J.; Knutz, Th.; Kolostelov, D.; Komlev, K.; Kontaxis, J.; Koske, P.; Learned, J. G.; Ledenev, V. V.; Leisos, A.; Limberopoulos, G.; Ludvig, J.; Makris, J.; Manousakis-Katsikakis, A.; Markopoulos, E.; Matsuno, S.; Mielke, J.; Mihos, Th.; Minkowski, P.; Mironovich, A. A.; Mitiguy, R.; Nounos, S.; Nygren, D. R.; Papageorgiou, K.; Passera, M.; Politis, C.; Preve, P.; Przybylski, G. T.; Rathlev, J.; Resvanis, L. K.; Rosen, M.; Schmidt, N.; Schmidt, Th.; Siotis, I.; Sopher, J.; Staveris, T.; Stavrakakis, G.; Stokstad, R.; Surin, N. M.; Tsagli, V.; Tsirigotis, A.; Tsirmpas, J.; Tzamarias, S.; Vasiliev, O.; Vaskine, O.; Voigt, W.; Vougioukas, A.; Voulgaris, G.; Zacharov, L. M.; Zheleznykh, I. M.; Zhukov, A.
2003-07-01
The first so-called flo or with 12 detector modules of the NESTOR deep sea high energy muon and neutrino telescope had been deployed successfully this March (2003) together with its electronics system. Since that data the system and the associated environmental monitoring units are operating properly and data
Results from the AMANDA telescope
Bouhali, O
2003-01-01
We present results from the AMANDA high energy neutrino telescope located at the South Pole. They include measurements of the atmospheric neutrino flux, search for UHE point sources, and diffuse sources producing electromagnetic/hadronic showers at the detector or close to it. (4 refs).
Cern Axion Solar Telescope (CAST)
2002-01-01
The CERN Solar Axion Telescope, CAST, aims to shed light on a 30-year-old riddle of particle physics by detecting axions originating from the 15 million degree plasma in the Sun 's core. Axions were proposed as an extension to the Standard Model of particle physics to explain why CP violation is observed in weak but not strong interactions.
Overdenture dengan Pegangan Telescopic Crown
Directory of Open Access Journals (Sweden)
Pambudi Santoso
2014-06-01
Full Text Available Kaitan presisi merupakan alat retensi mekanis yang menghubungkan antara satu atau lebih pegangan gigi tiruan, yang bertujuan untuk menambah retensi dan/atau stabilisasi. Kaitan presisi dapat digunakan secara luas pada gigi tiruan cekat, gigi tiruan sebagian lepasan, overdenture, implant untuk retensi overdenture, dan protesa maksilo fasial. Overdenture dengan kaitan presisi dapat membantu dalam pembagian beban kunyah, meminimalkan trauma pada gigi pegangan dan jaringan lunak, meminimalkan resorbsi tulang, dan meningkatkan estetik dan pengucapan suara. Salah satu jenis dari kaitan presisi adalah telescopic crown, terdiri dari 2 macam mahkota, yaitu mahkota primer yang melekat secara permanen pada gigi penyangga, dan mahkota sekunder yang melekat pada gigi tiruan. Tujuan pemaparan kasus ini adalah untuk memberikan informasi tentang rehabilitasi pasien edentulous sebagian rahang atas dengan telescopic crown.. Pasien wanita berusia 45 tahun datang ke klinik prostodonsia RSGM Prof.Soedomo dengan keluhan ingin dibuatkan gigi tiruan. Pasien kehilangan gigi 11 12 15 16 17 21 22 24 25 26 dan 27 yang diindikasikan untuk pembuatan overdenture gigi tiruan sebagian lepasan (GTS kerangka logam dengan pegangan telescopic crown pada gigi 13 dan 14 dengan sistem parallel-sided crown. Tahap-tahap pembuatan telescopic crown yaitu mencetak model study dengan catatan gigit pendahuluan. Perawatan saluran dilakukan pada akar gigi 13, dilanjutkan pemasangan pasak fiber serta rewalling dinding bukal. Gigi 13 dan 14 dilakukan preparasi mahkota penuh, dilanjutkan dengan pencetakan model kerja untuk coping primer dan kerangka logam dengan metode double impression. Coping primer disementasi pada gigi penyangga, dilanjutkan pasang coba coping sekunder beserta kerangka logam. Selanjutnya dilakukan pencatatan gigit, pencetakan model kerja, penyusunan gigi dan pasang coba penyusunan gigi pada pasien. Prosedur dilanjutkan dengan proses di laboratorium, serta insersi pada
The automated Palomar 60 inch telescope
Cenko, S Bradley; Fox, Derek B.; Moon, Dae-Sik; Harrison, Fiona A.; Kulkarni, S.R.; Henning, John R.; Guzman, C. Dani; Bonati, Marco; Smith, Roger M.; Thicksten, Robert P.; Doyle, Michael W.; Petrie, Hal L.; Gal-Yam, Avishay; Soderberg, Alicia M.; Anagnostou, Nathaniel L.
2006-01-01
We have converted the Palomar 60-inch telescope (P60) from a classical night assistant-operated telescope to a fully robotic facility. The automated system, which has been operational since September 2004, is designed for moderately fast (t
Hybrid resonance and long-time asymptotic of the solution to Maxwell's equations
Després, Bruno
2015-01-01
We study the long-time asymptotic of the solutions to Maxwell's equation in the case of a hybrid resonance in the cold plasma model. We base our analysis in the transfer to the time domain of the recent results of B. Despr\\'es, L.M. Imbert-G\\'erard and R. Weder, J. Math. Pures Appl. {\\bf 101} ( 2014) 623-659, where the singular solutions to Maxwell's equations in the frequency domain where 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 because hybrid resonances are a possible scenario for the heating of plasmas in the future ITER Tokamak.
Singh, Ashmeet
2012-01-01
A novel pedagogical technique is presented that can be used in the undergraduate (UG) class to formulate a relativistically extended Kinetic Theory of Gases and Maxwell-Boltzmann thermal speed distribution, while keeping the basic thermal symmetry arguments intact. The adopted framework can be used by students to understand the physics in a thermally governed system at high temperature and speeds, without having to indulge in high level tensor based mathematics. Our approach will first recapitulate what is taught and known in the UG class and then present a methodology that will help students to understand and derive the physics of relativistic thermal systems. The methodology uses simple tools well known in the UG class and involves a component of computational techniques that can be used to involve students in this exercise. We also present towards the end the interesting implications of the relativistically extended distribution and compare it with Maxwell-Boltzmann results at various temperatures.
Double Compactified d = 11 Supermembrane Dual as a Non-Commutative Super-Maxwell Theory
Martin, I; Restuccia, A
2000-01-01
The physical hamiltonian of the double compactified D=11 supermembrane dual with non trivial wrapping is explicitly obtained. It contains cubic and quartic interacting terms. It exactly agrees with the hamiltonian formulation of non-commutative super-Maxwell theory on the world volume, minimally coupled to seven scalars fields corresponding to the transverse coordinates to the brane. The non commutative star product is intrinsically obtained from the simplectic 2-form defined by the minimal configuration of the hamiltonian, that is by the pull-back to the world volume of the canonical conection 1-form on the Hopf fibring over $CP_n$. The constraint generating the area preserving diffeomorphism is reformulated as the Gauss constraint of the non-commutative super-Maxwell theory.
Energy Technology Data Exchange (ETDEWEB)
Nungesser, Ernesto; Rendall, Alan D [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Am Muehlenberg 1, 14476 Potsdam (Germany)
2009-05-21
A proof of strong cosmic censorship is presented for a class of solutions of the Einstein-Maxwell equations, those with polarized Gowdy symmetry. A key element of the argument is the observation that by means of a suitable choice of variables the central equations in this problem can be written in a form where they are identical to the central equations for general (i.e. non-polarized) vacuum Gowdy spacetimes. Using this, it is seen that the deep results of Ringstroem on strong cosmic censorship in the vacuum case have implications for the Einstein-Maxwell case. Working out the geometrical meaning of these analytical results leads to the main conclusion.
Tokarevskaya, N G; Red'kov, V M
2009-01-01
Complex formalism of Riemann - Silberstein - Majorana - Oppenheimer in Maxwell electrodynamics is extended to the case of arbitrary pseudo-Riemannian space - time in accordance with the tetrad recipe of Tetrode - Weyl - Fock - Ivanenko. In this approach, the Maxwell equations are solved exactly on the background of simplest static cosmological models, spaces of constant curvature of Riemann and Lobachevsky parameterized by spherical coordinates. Separation of variables is realized in the basis of Schr\\"odinger -- Pauli type, description of angular dependence in electromagnetic complex 3-vectors is given in terms of Wigner D-functions. In the case of compact Riemann model a discrete frequency spectrum for electromagnetic modes depending on the curvature radius of space and three discrete parameters is found. In the case of hyperbolic Lobachevsky model no discrete spectrum for frequencies of electromagnetic modes arises.
Circularly polarized few-cycle optical rogue waves: rotating reduced Maxwell-Bloch equations.
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.
Superconvergence of mixed finite element approximations to 3-D Maxwell's equations in metamaterials
Huang, Yunqing
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. © 2011 Elsevier Inc.
Energy Technology Data Exchange (ETDEWEB)
Zhao, Guangpu [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China); Jian, Yongjun, E-mail: jianyj@imu.edu.cn [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China); Chang, Long [School of Mathematics and Statistics, Inner Mongolia University of Finance and Economics, Hohhot, Inner Mongolia 010051 (China); Buren, Mandula [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China)
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. - Highlights: • MHD flow of the generalized Maxwell fluids under AC electric field is analyzed. • The MHD flow is confined to a two-dimensional rectangular micropump. • Analytical solution is obtained by using the method of separation of variables. • The influences of related parameters on the MHD velocity are discussed.
Mackay, Tom G
2015-01-01
The homogenization of a composite material comprising three isotropic dielectric materials was investigated. The component materials were randomly distributed as spherical particles, with the particles of two of the component materials being coupled to form dimers. The Bruggeman and Maxwell Garnett formalisms were developed to estimate the permittivity dyadic of the homogenized composite material (HCM), under the quasi-electrostatic approximation. Both randomly oriented and identically oriented dimers were accommodated; in the former case the HCM is isotropic, whereas in the latter case the HCM is uniaxial. Representative numerical results for composite materials containing dielectric--dielectric dimers demonstrate close agreement between the estimates delivered by the Bruggeman and Maxwell Garnett formalisms. For composite materials containing metal--dielectric dimers with moderate degrees of dissipation, the estimates of the two formalisms are in broad agreement, provided that the dimer volume fractions are...
Crouseilles, Nicolas; Faou, Erwan
2016-01-01
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. It turns out that the choice of this implicit method is crucial as even $L$-stable methods can lead to numerical instabilities for large values of $c$. 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.
An asymptotic preserving scheme for the relativistic Vlasov-Maxwell equations in the classical limit
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.
Remarks on the solutions of the Maxwell- Chern-Simons theories
Németh, Z A
1998-01-01
The large distance behavior of the Maxwell- Chern-Simons (MCS) equations is analyzed, and it is found that the pure Chern-Simons limit, (when the Maxwell term is dropped from the equations), does not describe the large distance limit of the MCS model. This necessitates the solution of the original problem. The MCS gauge theory coupled to a nonrelativistic matter field, (governed by the gauged non-linear Schrödinger equation), is studied. It turns out, that there are no regular self-dual solutions as in the pure Chern-Simons case, but the model admits interesting, though singular self-dual solutions. The properties of these solutions, and their large distance limits are analyzed.
Relativistic Vlasov-Maxwell modelling using finite volumes and adaptive mesh refinement
Wettervik, Benjamin Svedung; Siminos, Evangelos; Fülöp, Tünde
2016-01-01
The dynamics of collisionless plasmas can be modelled by the Vlasov-Maxwell system of equations. An Eulerian approach is needed to accurately describe processes that are governed by high energy tails in the distribution function, but is of limited efficiency for high dimensional problems. The use of an adaptive mesh can reduce the scaling of the computational cost with the dimension of the problem. Here, we present a relativistic Eulerian Vlasov-Maxwell solver with block-structured adaptive mesh refinement in one spatial and one momentum dimension. The discretization of the Vlasov equation is based on a high-order finite volume method. A flux corrected transport algorithm is applied to limit spurious oscillations and ensure the physical character of the distribution function. We demonstrate a speed-up by a factor of five, because of the use of an adaptive mesh, in a typical scenario involving laser-plasma interaction in the self-induced transparency regime.
Effects of Backreaction on Power-Maxwell Holographic Superconductors in Gauss-Bonnet Gravity
Salahi, Hamid Reza; Montakhab, Afshin
2016-01-01
We analytically and numerically investigate the properties of s-wave holographic superconductors by considering the effects of scalar and gauge fields on the background geometry in five dimensional Einstein-Gauss-Bonnet gravity. We assume the gauge field to be in the form of the Power-Maxwell nonlinear electrodynamics. We employ the Sturm-Liouville eigenvalue problem for analytical calculation of the critical temperature and the shooting method for the numerical investigation. Our numerical and analytical results indicate that higher curvature corrections affect condensation of the holographic superconductors with backreaction. We observe that the backreaction can decrease the critical temperature of the holographic superconductors, while the Power-Maxwell electrodynamics and Gauss-Bonnet coefficient term may increase the critical temperature of the holographic superconductors. We find that the critical exponent has the mean-field value $\\beta=1/2$, regardless of the values of Gauss-Bonnet coefficient, backre...
Maxwell equations in Duffin - Kemmer tetrad form, spherical waves in Riemann space S_3
Bogush, A A; Red'kov, V M
2009-01-01
The Duffin-Kemmer form of massless vector field (Maxwell field) is extended to the case of arbitrary pseudo-Riemannian space-time in accordance with the tetrad recipe of Tetrode-Weyl-Fock-Ivanenko. In this approach, the Maxwell equations are solved exactly on the background of simplest static cosmological model, space of constant curvature of Riemann parameterized by spherical coordinates. Separation of variables is realized in the basis of Schr\\"odinger- Pauli type, description of angular dependence in electromagnetic filed functions is given in terms of Wigner D-functions. A discrete frequency spectrum for electromagnetic modes depending on the curvature radius of space and three discrete parameters is found. 4-potentials for spherical electro- magnetic waves of magnetic and electric type have been constructed.
Two-Potential Formalism for Numerical Solution of the Maxwell Equations
Kudryavtsev, Alexey N
2012-01-01
A new formulation of the Maxwell equations based on two vector and two scalar potentials is proposed. The use of these potentials allows the electromagnetic field equations to be written in the form of a hyperbolic system. In contrast to the original Maxwell equations, this system contains only evolutionary equations and does not include equations having the character of differential constraints. This fact makes the new equations especially convenient for numerical simulations of electromagnetic processes; in particular, they can be solved by modern powerful shock-capturing methods based on approximation of spatial derivatives by upwind differences. The electromagnetic field both in vacuum and in an inhomogeneous material medium is considered. Examples of modeling the propagation of electromagnetic waves by means of solving the formulated system of equations with the use of modern high-order schemes are given. Key words: computational electrodynamics, two-potential formalism, numerical solution of hyperbolic ...
Maxwell's equal-area law for Gauss-Bonnet Anti-de Sitter black holes
Belhaj, A; Moumni, H El; Masmar, K; Sedra, M B
2014-01-01
Interpreting the cosmological constant \\Lambda as a thermodynamic pressure and its conjugate quantity as a thermodynamic volume, we study the Maxwell's equal area law of higher dimensional Gauss-Bonnet-AdS black holes in extended space. These black hole solutions critically behave like Van der Waals systems. It has been realized that below the critical temperature T_c the stable equilibrium is violated. We show through numerical calculations that the critical behaviors for the uncharged black holes only appear in d=5. For the charged case, we analyse solutions in d = 5 and d = 6 separately and find that, up to some constrains, the critical behaviors only appear in the spherical topology. Using the Maxwell's construction, we also find the isobar line for which the liquid-gas-like phases coexist.
Experimental Rectification of Entropy Production by Maxwell's Demon in a Quantum System
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.
A Comparison of Fick and Maxwell-Stefan Diffusion Formulations in PEMFC Cathode Gas Diffusion Layers
Lindstrom, Michael
2013-01-01
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. Formulations of diffusion combined with mass-averaged Darcy flow are considered for three component gases. Fick formulations can be considered as approximations of Maxwell-Stefan in a certain sense. For this application, the formulations can be compared computationally in a simple, one dimensional setting. We observe that the predictions of the formulations are very similar, despite their seemingly different structure. Analytic insight is given to the result. In addition, it is seen that for both formulations, diffusion laws are small perturbations from bulk flow. The work is also intended as a reference to multi-component gas diffusion formulations in the fuel cell setting.
Maxwell's fish-eye lens and the mirage of perfect imaging
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.
Stagnation point flow of Maxwell fluid towards a permeable surface in the presence of nanopar
Directory of Open Access Journals (Sweden)
G.K. Ramesh
2016-06-01
Full Text Available Analysis has been carried out to study the stagnation point flow of Maxwell fluid towards a permeable stretching sheet in the presence of nanoparticles. Using suitable transformations, the governing partial differential equations are first converted to ordinary one and then solved numerically by fourth–fifth order Runge–Kutta–Fehlberg method with MAPLE. The flow and heat transfer characteristics are analyzed and discussed for different values of the parameters. Present work reveals that the velocity increases whereas the temperature and concentration decrease with the increase of Maxwell parameter. The thermal and concentration boundary layer thickness decreases with velocity ratio, Lewis number, Prandtl number suction, Brownian motion and thermophoresis parameters. Comparison with known results for Newtonian fluid flow is found an excellent agreement.
Entanglement entropy for a Maxwell field: Numerical calculation on a two dimensional lattice
Casini, Horacio
2014-01-01
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 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. 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 non standard way in which strong subaddi...
Hybrid resonance and long-time asymptotic of the solution to Maxwell's equations
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.
Galagusz, Ryan; Nave, Jean-Christophe
2015-01-01
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 irregular non-periodic domain of the equations to a regular 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...
Maxwell's macroscopic equations, the energy-momentum postulates, and the Lorentz law of force
Mansuripur, Masud
2013-01-01
We argue that the classical theory of electromagnetism is based on Maxwell's macroscopic equations, an energy postulate, a momentum postulate, and a generalized form of the Lorentz law of force. These seven postulates constitute the foundation of a complete and consistent theory, thus eliminating the need for actual (i.e., physical) models of polarization P and magnetization M, these being the distinguishing features of Maxwell's macroscopic equations. In the proposed formulation, P(r,t) and M(r,t) are arbitrary functions of space and time, their physical properties being embedded in the seven postulates of the theory. The postulates are self-consistent, comply with the requirements of the special theory of relativity, and satisfy the laws of conservation of energy, linear momentum, and angular momentum. One advantage of the proposed formulation is that it side-steps the long-standing Abraham-Minkowski controversy surrounding the electromagnetic momentum inside a material medium by simply "assigning" the Abra...
Maxwell's second- and third-order equations of transfer for non-Maxwellian gases
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.
Sources of gravitational waves in asymptotically flat Einstein-Maxwell spacetime
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.
Origins Space Telescope: Telescope Design and Instrument Specifications
Meixner, Margaret; Carter, Ruth; Leisawitz, David; Dipirro, Mike; Flores, Anel; Staguhn, Johannes; Kellog, James; Roellig, Thomas L.; Melnick, Gary J.; Bradford, Charles; Wright, Edward L.; Zmuidzinas, Jonas; Origins Space Telescope Study Team
2017-01-01
The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. The renaming of the mission reflects Origins science goals that will discover and characterize the most distant galaxies, nearby galaxies and the Milky Way, exoplanets, and the outer reaches of our Solar system. This poster will show the preliminary telescope design that will be a large aperture (>8 m in diameter), cryogenically cooled telescope. We will also present the specifications for the spectrographs and imagers over a potential wavelength range of ~10 microns to 1 millimeter. We look forward to community input into this mission definition over the coming year as we work on the concept design for the mission. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. We welcome you to contact the Science and Technology Definition Team (STDT) with your science needs and ideas by emailing us at firsurveyor_info@lists.ipac.caltech.edu.
Alignment of the James Webb Space Telescope optical telescope element
Glassman, Tiffany; Levi, Joshua; Liepmann, Till; Hahn, Walter; Bisson, Gary; Porpora, Dan; Hadjimichael, Theo
2016-07-01
The optical telescope element (OTE) of the James Webb Space Telescope has now been integrated and aligned. The OTE comprises the flight mirrors and the structure that supports them - 18 primary mirror segments, the secondary mirror, and the tertiary and fine steering mirrors (both housed in the aft optics subsystem). The primary mirror segments and the secondary mirror have actuators to actively control their positions during operations. This allows the requirements for aligning the OTE subsystems to be in the range of microns rather than nanometers. During OTE integration, the alignment of the major subsystems of the OTE structure and optics were controlled to ensure that, when the telescope is on orbit and at cryogenic temperatures, the active mirrors will be within the adjustment range of the actuators. Though the alignment of this flagship mission was complex and intricate, the key to a successful integration process turned out to be very basic: a clear, concise series of steps employing advanced planning, backup measurements, and cross checks that this multi-organizational team executed with a careful and methodical approach. This approach was not only critical to our own success but has implications for future space observatories.
The Medium Size Telescopes of the Cherenkov Telescope Array
Pühlhofer, G
2016-01-01
The Cherenkov Telescope Array (CTA) is the planned next-generation instrument for ground-based gamma-ray astronomy, covering a photon energy range of ~20 GeV to above 100 TeV. CTA will consist of the order of 100 telescopes of three sizes, installed at two sites in the Northern and Southern Hemisphere. This contribution deals with the 12 meter Medium Size Telescopes (MST) having a single mirror (modified Davies-Cotton, DC) design. In the baseline design of the CTA arrays, 25 MSTs in the South and 15 MSTs in the North provide the necessary sensitivity for CTA in the core energy range of 100 GeV to 10 TeV. DC-MSTs will be equipped with photomultiplier (PMT)-based cameras. Two options are available for these focal plane instruments, that will be provided by the FlashCam and the NectarCAM sub-consortia. In this contribution, a short introduction to the projects and their status is given.
Cosmological Einstein-Maxwell instantons and Euclidean supersymmetry: anti-self-dual solutions
Energy Technology Data Exchange (ETDEWEB)
Dunajski, Maciej [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Gutowski, Jan [Department of Mathematics, King' s College London, Strand, London WC2R 2LS (United Kingdom); Sabra, Wafic [Centre for Advanced Mathematical Sciences and Physics Department, American University of Beirut, Beirut (Lebanon); Tod, Paul, E-mail: m.dunajski@damtp.cam.ac.uk, E-mail: jan.gutowski@kcl.ac.uk, E-mail: ws00@aub.edu.lb, E-mail: paul.tod@sjc.ox.ac.uk [The Mathematical Institute, Oxford University, 24-29 St Giles, Oxford OX1 3LB (United Kingdom)
2011-01-21
We classify super-symmetric solutions of the minimal N = 2 gauged Euclidean supergravity in four dimensions. The solutions with an anti-self-dual Maxwell field give rise to anti-self-dual Einstein metrics given in terms of solutions to the SU({infinity}) Toda equation and more general three-dimensional Einstein-Weyl structures. Euclidean Kastor-Traschen metrics are also characterized by the existence of a certain supercovariantly constant spinor.
Vortex Dynamics in Selfdual Maxwell-Higgs Systems with Uniform Background Electric Charge Density
Lee, K M
1994-01-01
We introduce selfdual Maxwell-Higgs systems with uniform background electric charge density and show that the selfdual equations satisfied by topological vortices can be reduced to the original Bogomol'nyi equations without any background. These vortices are shown to carry no spin but to feel the Magnus force due to the shielding charge carried by the Higgs field. We also study the dynamics of slowly moving vortices and show that the spin-statistics theorem holds to our vortices.
Dynamical Mass Generation and Confinement in Maxwell-Chern-Simons Planar Quantum Electrodynamics
Energy Technology Data Exchange (ETDEWEB)
Sanchez Madrigal, S; Raya, A [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Ciudad Universitaria, Morelia, Michoacan 58040 (Mexico); Hofmann, C P, E-mail: saul@ifm.umicri.mx, E-mail: christoph@ucol.mx, E-mail: raya@ifm.umich.mx [Facultad de Ciencias, Universidad de Colima, Bernal Diaz del Castillo 340, Colima, Colima 28045 (Mexico)
2011-04-01
We study the non-perturbative phenomena of Dynamical Mass Generation and Confinement by truncating at the non-perturbative level the Schwinger-Dyson equations in Maxwell-Chern-Simons planar quantum electrodynamics. We obtain numerical solutions for the fermion propagator in Landau gauge within the so-called rainbow approximation. A comparison with the ordinary theory without the Chern-Simons term is presented.
Using Two Types of Computer Algebra Systems to Solve Maxwell Optics Problems
Kulyabov, D. S.
2016-01-01
To synthesize Maxwell optics systems, the mathematical apparatus of tensor and vector analysis is generally employed. This mathematical apparatus implies executing a great number of simple stereotyped operations, which are adequately supported by computer algebra systems. In this paper, we distinguish between two stages of working with a mathematical model: model development and model usage. Each of these stages implies its own computer algebra system. As a model problem, we consider the prob...
RADIATION BOUNDARY CONDITIONS FOR MAXWELL'S EQUATIONS: A REVIEW OF ACCURATE TIME-DOMAIN FORMULATIONS
Institute of Scientific and Technical Information of China (English)
Thomas Hagstrom; Stephen Lau
2007-01-01
We review time-domain formulations of radiation boundary conditions for Maxwell's equations, focusing on methods which can deliver arbitrary accuracy at acceptable computational cost. Examples include fast evaluations of nonlocal conditions on symmetric and general boundaries, methods based on identifying and evaluating equivalent sources, and local approximations such as the perfectly matched layer and sequences of local boundary conditions. Complexity estimates are derived to assess work and storage requirements as a function of wavelength and simulation time.
Future complete S{sup 1} symmetric solutions of the Einstein Maxwell Higgs system
Energy Technology Data Exchange (ETDEWEB)
Choquet-Bruhat, Yvonne [Academic des Sciences, 23 Quai Conti, 75006 Paris (France)
2005-01-01
In previous works we have obtained a proof of the non linear stability (i.e. future completeness for small initial data) of Einsteinian vacuum spacetimes with compact space sections and a S{sup 1} spatial isometry group, in the case where the space is an S{sup 1} bundle over a surface {sigma} of genus greater than one. We intend in this paper to extend this result to the Einstein Maxwell Higgs system.
Generalized thermodynamic identity and new Maxwell's law for charged AdS black hole
Zhao, Zixu
2016-01-01
We study the thermodynamic properties of the RN-AdS black hole in full phase space and propose a generalized thermodynamic identity. As an example, we use it to find relations of thermodynamical coefficients between the grand canonical and canonical ensembles. We also show, for the first order phase transition, that the usual Maxwell's equal area law should be extended to a new form for the RN-AdS black hole.
Loop Representation of charged particles interacting with Maxwell and Chern-Simons fields
Fuenmayor, E; Revoredo, R; Fuenmayor, Ernesto; Leal, Lorenzo; Revoredo., Ryan
2002-01-01
The loop representation formulation of non-relativistic particles coupled with abelian gauge fields is studied. Both Maxwell and Chern-Simons interactions are separately considered. It is found that the loop-space formulations of these models share significant similarities, although in the Chern-Simons case there exists an unitary transformation that allows to remove the degrees of freedom associated with the paths. As a general result, we find that charge quantization is necessary for the geometric representation to be consistent.
Exact Solution of Unsteady Flow of Viscoelastic Fluid in a Pipe with Fractional Maxwell Model
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The unsteady flow of viscoelastic fluid in a cylindrical pipe was investigated using the fractional Maxwell model. Two special cases of unsteady pipe flow were expressed. The first is start-up flow, and the second is oscillating flow. The exact solution of start-up flow under a constant pressure gradient was obtained by using the theories of Laplace transform and Fourier-Bessel series for fractional derivatives. The exact solution of oscillating flow was obtained by utilizing the separation of variables.
Gimbutas, Zydrunas
2011-01-01
A variety of problems in device and materials design require the rapid forward modeling of Maxwell's equations in complex micro-structured materials. By combining high-order accurate integral equation methods with classical multiple scattering theory, we have created an effective simulation tool for materials consisting of an isotropic background in which are dispersed a large number of micro- or nano-scale metallic or dielectric inclusions.
A Short History of The Air University, Maxwell AFB, and the 42nd Air Base Wing
2014-07-31
the nation’s first civilian flying school on an old cotton plantation near Montgomery that subsequently become Maxwell Air Force Base (AFB...on New Guinea, Celebes, and Halmahera, and flew reconnaissance missions. Moved to the Philippines in Feb–Mar 1945. Attacked shipping along the China ...Western Pacific; Leyte; Luzon; Southern Philippines; China Defensive; China Offensive. Southwest Asia: Defense of Saudi Arabia; Liberation and Defense
Spacetimes with Killing tensors. [for Einstein-Maxwell fields with certain spinor indices
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.
Flathmann, Kai
2015-01-01
In this article we study the geodesic motion of test particles and light in the Einstein-Maxwell-Dilaton-Axion black hole spacetime. We derive the equations of motion and present their solutions in terms of the Weierstra{\\ss} $\\wp$-, $\\sigma$- and $\\zeta$-functions. With the help of parametric diagrams and effective potentials we analyze the geodesic motion and give a list of all possible orbit types.
Infinitely many large energy solutions of superlinear Schrodinger-Maxwell equations
Directory of Open Access Journals (Sweden)
Lin Li
2012-12-01
Full Text Available In this article we study the existence of infinitely many large energy solutions for the superlinear Schrodinger-Maxwell equations $$displaylines{ -Delta u+V(xu+ phi u=f(x,u quad hbox{in }mathbb{R}^3,cr -Delta phi=u^2, quad hbox{in }mathbb{R}^3, }$$ via the Fountain Theorem in critical point theory. In particular, we do not use the classical Ambrosetti-Rabinowitz condition.
Computer Algebra meets Finite Elements: an Efficient Implementation for Maxwell's Equations
Koutschan, Christoph; Schoeberl, Joachim
2011-01-01
We consider the numerical discretization of the time-domain Maxwell's equations with an energy-conserving discontinuous Galerkin finite element formulation. This particular formulation allows for higher order approximations of the electric and magnetic field. Special emphasis is placed on an efficient implementation which is achieved by taking advantage of recurrence properties and the tensor-product structure of the chosen shape functions. These recurrences have been derived symbolically with computer algebra methods reminiscent of the holonomic systems approach.
Simultaneous exact controllability for Maxwell equations and for a second-order hyperbolic system
Directory of Open Access Journals (Sweden)
Boris V. Kapitonov
2010-02-01
Full Text Available We present a result on "simultaneous" exact controllability for two models that describe two hyperbolic dynamics. One is the system of Maxwell equations and the other a vector-wave equation with a pressure term. We obtain the main result using modified multipliers in order to generate a necessary observability estimate which allow us to use the Hilbert Uniqueness Method (HUM introduced by Lions.
New exact solutions of the Einstein-Maxwell equations for magnetostatic fields
Institute of Scientific and Technical Information of China (English)
Nisha Goyal; R. K. Gupta
2012-01-01
The symmetry reduction method based on the Fréchet derivative of differential operators is applied to investigate symmetries of the Einstein-Maxwell field equations for magnetostatic fields,which is a coupled system of nonlinear partial differential equations of the second order.The technique yields invariant transformations that reduce the given system of partial differential equations to a system of nonlinear ordinary differential equations.Some of the reduced systems are further studied to obtain the exact solutions.
Non-minimal Maxwell-Chern-Simons theory and the composite Fermion model
Energy Technology Data Exchange (ETDEWEB)
Paschoal, Ricardo C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Servico Nacional de Aprendizagem Industrial (SENAI), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia da Industria Quimica e Textil (CETIQT); Helayel Neto, Jose A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Grupo de Fisica Teorica Jose Leite Lopes, Petropolis, RJ (Brazil); E-mails: paschoal@cbpf.br; helayel@cbpf.br
2003-01-01
The magnetic field redefinition in Jain's composite fermion model for the fractional quantum Hall effect is shown to be effective described by a mean-field approximation of a model containing a Maxwell-Chern-Simons gauge field nominally coupled to matter. Also an explicit non-relativistic limit of the non-minimal (2+1) D Dirac's equation is derived. (author)
NUMERICAL METHODS FOR MAXWELL'S EQUATIONS IN INHOMOGENEOUS MEDIA WITH MATERIAL INTERFACES
Institute of Scientific and Technical Information of China (English)
Wei Cai
2004-01-01
In this paper, we will present some recent results on developing numerical methods for solving Maxwell's equations in inhomogeneous media with material interfaces. First,we will present a second order upwinding embedded boundary method - a Cartesian grid based finite difference method with special upwinding treatment near the material interfaces. Second, we will present a high order discontinuous spectral element with Dubinar orthogonal polynomials on triangles. Numerical results on electromagnetic scattering and photonic waveguide will be included.
Maxwell-Bloch Equations Modeling of Ultrashort Optical Pulse Propagation in Semiconductor Materials
Goorjian, Peter M.; Agrawal, Govind, P.
1997-01-01
An algorithm has been developed that solves the semiconductor Maxwell-Bloch equations, without making the standard slowly-varying envelope (SVEA) and rotating-wave (RWA) approximations. It is applied to study the propagation of ultrashort pulses in semiconductor materials. The results include many-body effects due to the Coulomb interaction among the charge carriers as well as the nonlinear effects resulting from spectral hole-burning.
Spectral Method for Solving Time Dependent Flow of Upper-Convected Maxwell Fluid in Tube
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The time dependent flow of upper-convected Maxwell fluid in a horizontal circular pipe is studied by spectral method. The time dependent problem is mathematically reduced to a partial differential equation of second order. By using spectral method the partial differential equation can be reduced to a system of ordinary differential equations for different terms of Chebyshev polynomials approximations. The ordinary differential equations are solved by Laplace transform and the eigenvalue method that leads to an analytical form of the solutions.
Geometric Integration Of The Vlasov-Maxwell System With A Variational Particle-in-cell Scheme
Energy Technology Data Exchange (ETDEWEB)
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.
Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme
Energy Technology Data Exchange (ETDEWEB)
Squire, J.; Tang, W. M. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Qin, H. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)
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.
Geometric integration of the Vlasov-Maxwell system with a variational particle-in-cell scheme
2014-01-01
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, 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.
The Hubble Space Telescope: Problems and Solutions.
Villard, Ray
1990-01-01
Presented is the best understanding of the flaw discovered in the optics of the Hubble Space Telescope and the possible solutions to the problems. The spherical aberration in the telescope's mirror and its effect on the quality of the telescope's imaging ability is discussed. (CW)
CFRP lightweight structures for extremely large telescopes
DEFF Research Database (Denmark)
Jessen, Niels Christian; Nørgaard-Nielsen, Hans Ulrik; Schroll, J.
2008-01-01
Telescope structures are traditionally built out of steel. To improve the possibility of realizing the ambitious extremely large telescopes, materials with a higher specific stiffness and a lower coefficient of thermal expansion are needed. An important possibility is Carbon Fibre Reinforced...... Plastic (CFRP). The advantages of using CFRP for the secondary mirror support structure of the European overwhelmingly large telescope are discussed....
The Principles of Astronomical Telescope Design
Cheng, Jingquan
2009-01-01
Presents a summary of the author's twenty five years of experience in telescope design. This work provides a general introduction to various aspects of telescope design. It discusses the theory behind telescope design. It covers Radio, Infrared, Optical, X-Ray and Gamma-Ray wavelengths
Area inequalities for stable marginally outer trapped surfaces in Einstein-Maxwell-dilaton theory
Fajman, David
2013-01-01
We prove area inequalities for stable marginally outer trapped surfaces in Einstein-Maxwell-dilaton theory. Our inspiration comes on the one hand from a corresponding recent upper bound for the area in terms of the charges obtained by Dain, Jaramillo and Reiris [1] in the pure Einstein-Maxwell case without symmetries, and on the other hand from Yazadjiev's inequality [2] in the axially symmetric Einstein-Maxwell-dilaton case. The common issue in these proofs and in the present one is a functional ${\\mathscr W}$ of the matter fields for which the stability condition readily yields an {\\it upper} bound. On the other hand, the step which crucially depends on whether or not a dilaton field is present is to obtain a {\\it lower} bound for ${\\mathscr W}$ as well. We obtain the latter by first setting up a variational principle for ${\\mathscr W}$ with respect to the dilaton field $\\phi$, then by proving existence of a minimizer $\\psi$ as solution of the corresponding Euler-Lagrange equations and finally by estimating...
A comparison of Fick and Maxwell-Stefan diffusion formulations in PEMFC gas diffusion layers
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.
Pusch, Andreas; Wuestner, Sebastian; Hamm, Joachim M; Tsakmakidis, Kosmas L; Hess, Ortwin
2012-03-27
Nanoplasmonic metamaterials are an exciting new class of engineered media that promise a range of important applications, such as subwavelength focusing, cloaking, and slowing/stopping of light. At optical frequencies, using gain to overcome potentially not insignificant losses has recently emerged as a viable solution to ultra-low-loss operation that may lead to next-generation active metamaterials. Maxwell-Bloch models for active nanoplasmonic metamaterials are able to describe the coherent spatiotemporal and nonlinear gain-plasmon dynamics. Here, we extend the Maxwell-Bloch theory to a Maxwell-Bloch Langevin approach-a spatially resolved model that describes the light field and noise dynamics in gain-enhanced nanoplasmonic structures. Using the example of an optically pumped nanofishnet metamaterial with an embedded laser dye (four-level) medium exhibiting a negative refractive index, we demonstrate the transition from loss-compensation to amplification and to nanolasing. We observe ultrafast relaxation oscillations of the bright negative-index mode with frequencies just below the THz regime. The influence of noise on mode competition and the onset and magnitude of the relaxation oscillations is elucidated, and the dynamics and spectra of the emitted light indicate that coherent amplification and lasing are maintained even in the presence of noise and amplified spontaneous emission.
Hybrid Method of combined difference and spectrum for time-domain maxwell's equations
Institute of Scientific and Technical Information of China (English)
QI Hong-xing; CHEN Shu-de; QIAO Deng-jiang; PANG Xiao-feng
2006-01-01
For the finite-difference time domain (FDTD)method,the electromagnetic scattering problem,which requires the characteristic structure size to be much smaller than the wavelength of the exciting source,is still a challenge.To circumvent this difficulty,this paper presents a novel hybrid numerical technique of combined difference and spectrum for time-domain Maxwell's equations.With periodical continuation of each time-dependent quantity in Maxwell's equations,the solutions before and after the continuation remain consistent in the first period,which results in the conversion of the continuous spectrum problem to a discrete one.The discrete spectrum of the field after continuation is obtained from difference methods for Maxwell's curl equations in frequency-domain,and the time domain solution of the original problem is derived from their inverse Fourier transform.Due to its unconditional stability,the proposed scheme excels FDTD in resolving the aforementioned problems.In addition,this method can simulate dispersive media whose electric susceptibility cannot be expressed with Debye or Lorentz types of models.In dealing with boundary conditions,it can utilize the perfectly matched layer (PML) without extra codes.Numerical experiments demonstrate its effectiveness,easy implementation and high precision.
A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer
Institute of Scientific and Technical Information of China (English)
Kadry Zakaria; Magdy A. Sirwah; Sameh A. Alkharashi
2011-01-01
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.
A Two-Layer Model for Superposed Electrified Maxwell Fluids in Presence of Heat Transfer
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.
On the different forms of the Maxwell's electromagnetic equations in a uniform media
Redkov, V A; V.A., Red'kov; Spix, George J.
2006-01-01
Two known, alternative to each other, forms of the Maxwell's electromagnetic equations in a moving uniform media are investigated and discussed. Approach commonly used after Minkowski is based on the two tensors: H^{ab} = (D, H /c) and F^{ab} = (E, cB) which transform independently of each other at Lorentz transitions; relationships between fields change their form at Lorentz transformations and have the form of the Minkowski equations depending on the 4-velocity u^{a} of the moving media under an inertial reference frame. So, the electrodynamics by Minkowski implies the absolute nature of the mechanical motion. An alternative formalism (Rosen and others) may be developed in the new variables. This form of the the Maxwell's equations exhibits symmetry under modified Lorentz transformations in which everywhere instead of the vacuum speed of light c is used the speed of light in the media, kc . In virtue of this symmetry we might consider such a formulation of the Maxwell theory in the media as invariant under ...
Higher-derivative gravity with non-minimally coupled Maxwell field
Energy Technology Data Exchange (ETDEWEB)
Feng, Xing-Hui; Lue, H. [Beijing Normal University, Department of Physics, Center for Advanced Quantum Studies, Beijing (China)
2016-04-15
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. (orig.)
Sheykhi, A; Davatolhagh, S
2016-01-01
The properties of $(d-1)$-dimensional $s$-wave holographic superconductor in the presence of power-Maxwell field is explored. We study the probe limit in which the scalar and gauge fields do not backreact on the background geometry. Our study is based on the matching of solutions on the boundary and on the horizon at some intermediate point. At first, the case without external magnetic field is considered, and the critical temperature is obtained in terms of the charge density, the dimensionality, and the power-Maxwell exponent. Then, a magnetic field is turned on in the $d$-dimensional bulk which can influence the $(d-1)$-dimensional holographic superconductor at the boundary. The phase behavior of the corresponding holographic superconductor is obtained by computing the upper critical magnetic field in the presence of power-Maxwell electrodynamics, characterized by the power exponent $q$. Interestingly, it is observed that in the presence of magnetic field, the physically acceptable phase behavior of the ho...
Duality, Quantum Vortices and Anyons in Maxwell-Chern-Simons-Higgs Theories
Marino, E C
1993-01-01
The order-disorder duality structure is exploited in order to obtain a quantum description of anyons and vortices in: a) the Maxwell theory; b) the Abelian Higgs Model; c) the Maxwell-Chern-Simons theory; d) the Maxwell-Chern-Simons-Higgs theory. A careful construction of a charge bearing order operator($\\sigma$) and a magnetic flux bearing disorder operator (vortex operator) ($\\mu$) is performed, paying attention to the necessary requirements for locality. An anyon operator is obtained as the product $\\varphi=\\sigma\\mu$. A detailed and comprehensive study of the euclidean correlation functions of $\\sigma$, $\\mu$ and $\\varphi$ is carried on in the four theories above. The exact correlation functions are obtained in cases $\\underline{a}$ and $\\underline{c}$. The large distance behavior of them is obtained in cases $\\underline{b}$ and $\\underline{d}$. The study of these correlation functions allows one to draw conclusions about the condensation of charge and magnetic flux, establishing thereby an analogy with t...
Su, Hongling; Li, Shengtai
2016-04-01
In this paper, 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. 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.
Interaction of magnetic field in flow of Maxwell nanofluid with convective effect
Energy Technology Data Exchange (ETDEWEB)
Hayat, T. [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah 21589 (Saudi Arabia); Muhammad, Taseer, E-mail: taseer_qau@yahoo.com [Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan); Shehzad, S.A. [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Chen, G.Q. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80203, Jeddah 21589 (Saudi Arabia); Laboratory of Systems Ecology, College of Engineering, Peking University, Beijing 100871 (China); Abbas, Ibrahim A. [Mathematics Department (Khulais), Faculty of Science and Arts, King Abdulaziz University, Jeddah 21589 (Saudi Arabia)
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. - Highlights: • Three-dimensional flow of Maxwell fluid. • Consideration of nanoparticles effect. • Formulation through convective condition. • Analysis in magnetohydrodynamic regime. • Utilization of new condition associated with mass flux.
Thermodynamics of charged rotating dilaton black branes with power-law Maxwell field
Energy Technology Data Exchange (ETDEWEB)
Zangeneh, M.K. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Sheykhi, A.; Dehghani, M.H. [Shiraz University, Physics Department and Biruni Observatory, College of Sciences, Shiraz (Iran, Islamic Republic of); Research Institute for Astronomy and Astrophysics of Maragha (RIAAM), P.O.Box 55134-441, Maragha (Iran, Islamic Republic of)
2015-10-15
In this paper, we construct a new class of charged rotating dilaton black brane solutions, with a complete set of rotation parameters, which is coupled to a nonlinear Maxwell field. The Lagrangian of the matter field has the form of the power-law Maxwell field. We study the causal structure of the spacetime and its physical properties in ample details. We also compute thermodynamic and conserved quantities of the spacetime, such as the temperature, entropy, mass, charge, and angular momentum. We find a Smarr-formula for the mass and verify the validity of the first law of thermodynamics on the black brane horizon. Finally, we investigate the thermal stability of solutions in both the canonical and the grand-canonical ensembles and disclose the effects of dilaton field and nonlinearity of the Maxwell field on the thermal stability of the solutions. We find that, for α ≤ 1, charged rotating black brane solutions are thermally stable independent of the values of the other parameters. For α > 1, the solutions can encounter an unstable phase depending on the metric parameters. (orig.)
Higher-Derivative Gravity with Non-minimally Coupled Maxwell Field
Feng, Xing-Hui
2016-01-01
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 o...
Hybrid resonance and long-time asymptotic of the solution to Maxwell's equations
Energy Technology Data Exchange (ETDEWEB)
Després, Bruno, E-mail: despres@ann.jussieu.fr [Laboratory Jacques Louis Lions, University Pierre et Marie Curie, Paris VI, Boîte courrier 187, 75252 Paris Cedex 05 (France); Weder, Ricardo, E-mail: weder@unam.mx [Departamento de Física Matemática, Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Apartado Postal 20-126, DF 01000 (Mexico)
2016-03-22
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. - Highlights: • The upper-hybrid resonance in the cold plasma model is considered. • The long-time asymptotic of the solutions to Maxwell's equations is studied. • A method based in a singular limiting absorption principle is proposed.
Exact solutions of the Bianchi types V and IX via time-dependent quasi-Maxwell equations
Yavari, Morteza
2014-02-01
The exact solutions of the Einstein field equations for the Bianchi types V and IX in presence of a perfect fluid via the time-dependent quasi-Maxwell (TQM) equations are investigated by using the threading formalism.
Comment on 'Note on Faraday's law and Maxwell's equations'
Energy Technology Data Exchange (ETDEWEB)
Redzic, Dragan V [Faculty of Physics, University of Belgrade, PO Box 368, 11001 Beograd (Yugoslavia)], E-mail: redzic@ff.bg.ac.yu
2008-11-15
We discuss some problematic contentions in a recent note on Faraday's law (Kholmetskii et al 2008 Eur. J. Phys. 29 N5-10). We also do justice to Hertz, Helmholtz and Maxwell. (letters and comments)
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.
Highlights from the Telescope Array
Directory of Open Access Journals (Sweden)
Matthews J.N.
2016-01-01
Full Text Available The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth’s surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.
O'Dell, Stephen; Brissenden, Roger; Davis, William; Elsner, Ronald; Elvis, Martin; Freeman, Mark; Gaetz, Terrance; Gorenstein, Paul; Gubarev, Mikhall; Jerlus, Diab; Juda, Michael; Kolodziejczak, Jeffrey; Murray, Stephen; Petre, Robert; Podgorski, William; Ramsey, Brian; Reid, Paul; Saha, Timo; Wolk, Scott; Troller-McKinstry, Susan; Weisskopf, Martin; Wilke, Rudeger; Zhang, William
2010-01-01
During the half-century history of x-ray astronomy, focusing x-ray telescopes, through increased effective area and finer angular resolution, have improved sensitivity by 8 orders of magnitude. Here, we review previous and current x-ray-telescope missions. Next, we describe the planned next-generation x-ray-astronomy facility, the International X-ray Observatory (IXO). We conclude with an overview of a concept for the next next-generation facility, Generation X. Its scientific objectives will require very large areas (about 10,000 sq m) of highly-nested, lightweight grazing-incidence mirrors, with exceptional (about 0.1-arcsec) resolution. Achieving this angular resolution with lightweight mirrors will likely require on-orbit adjustment of alignment and figure.
Cherenkov Telescope Array Data Management
Lamanna, G; Contreras, J L; Knödlseder, J; Kosack, K; Neyroud, N; Aboudan, A; Arrabito, L; Barbier, C; Bastieri, D; Boisson, C; Brau-Nogué, S; Bregeon, J; Bulgarelli, A; Carosi, A; Costa, A; De Cesare, G; Reyes, R de los; Fioretti, V; Gallozzi, S; Jacquemier, J; Khelifi, B; Kocot, J; Lombardi, S; Lucarelli, F; Lyard, E; Maier, G; Massimino, P; Osborne, J P; Perri, M; Rico, J; Sanchez, D A; Satalecka, K; Siejkowski, H; Stolarczyk, T; Szepieniec, T; Testa, V; Walter, R; Ward, J E; Zoli, A
2015-01-01
Very High Energy gamma-ray astronomy with the Cherenkov Telescope Array (CTA) is evolving towards the model of a public observatory. Handling, processing and archiving the large amount of data generated by the CTA instruments and delivering scientific products are some of the challenges in designing the CTA Data Management. The participation of scientists from within CTA Consortium and from the greater worldwide scientific community necessitates a sophisticated scientific analysis system capable of providing unified and efficient user access to data, software and computing resources. Data Management is designed to respond to three main issues: (i) the treatment and flow of data from remote telescopes; (ii) "big-data" archiving and processing; (iii) and open data access. In this communication the overall technical design of the CTA Data Management, current major developments and prototypes are presented.
The Ortega Telescope Andor CCD
Tucker, M.; Batcheldor, D.
2012-07-01
We present a preliminary instrument report for an Andor iKon-L 936 charge-couple device (CCD) being operated at Florida Tech's 0.8 m Ortega Telescope. This camera will replace the current Finger Lakes Instrumentation (FLI) Proline CCD. Details of the custom mount produced for this camera are presented, as is a quantitative and qualitative comparison of the new and old cameras. We find that the Andor camera has 50 times less noise than the FLI, has no significant dark current over 30 seconds, and has a smooth, regular flat field. The Andor camera will provide significantly better sensitivity for direct imaging programs and, once it can be satisfactorily tested on-sky, will become the standard imaging device on the Ortega Telescope.
Focusing Telescopes in Nuclear Astrophysics
Ballmoos, Peter von
2007-01-01
This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time. The volume also presents an overview of detectors matching the ambitious objectives of gamma ray optics, and facilities for operating such systems on the ground and in space. The extraordinary scientific potential of focusing gamma-ray telescopes for the study of the most powerful sources and the most violent events in the Universe is emphasized in a series of introductory articles. Practicing professionals, and students interested in experimental high-energy astrophysics, will find this book a useful reference
Directory of Open Access Journals (Sweden)
Gilles Carbou
2015-02-01
Full Text Available We study the Landau-Lifshitz system associated with Maxwell equations in a bilayered ferromagnetic body when super-exchange and surface anisotropy interactions are present in the spacer in-between the layers. In the presence of these surface energies, the Neumann boundary condition becomes nonlinear. We prove, in three dimensions, the existence of global weak solutions to the Landau-Lifshitz-Maxwell system with nonlinear Neumann boundary conditions.
Electron-electron attractive interaction in Maxwell-Chern-Simons QED{sub 3} at zero temperature
Energy Technology Data Exchange (ETDEWEB)
Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: belich@cbpf.br; manojr@cbpf.br; helayel@gft.ucp.br; Ferreira Junior, M.M. [Universidade Catolica de Petropolis, RJ (Brazil). Grupo de Fisica Teorica. E-mail: delcima@gft.ucp.br
2001-04-01
One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED{sub 3} with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)
The James Webb Space Telescope
Gardner, Jonathan P.
2011-01-01
The James Webb Space Telescope is the scientific successor to the Hubble and Spitzer Space Telescopes, and is currently the largest scientific project under construction in the United States. It will be a large (6.6m) cold (50K) telescope launched into orbit around the second Earth-Sun Lagrange point. It is a partnership of NASA with the European and Canadian Space Agencies. Science with the James Webb Space Telescope falls into four themes. The End of the Dark Ages: First Light and Reionization theme seeks to identify the first luminous sources to form and to determine the ionization history of the universe. The Assembly of Galaxies theme seeks to determine how galaxies and the dark matter, gas, stars, metals, morphological structures, and black holes within them evolved from the epoch of reionization to the present. The Birth of Stars and Protoplanetary Systems theme seeks to unravel the birth and early evolution of stars, from infall onto dust-enshrouded protostars, to the genesis of planetary systems. The Planetary Systems and the Origins of Life theme seeks to determine the physical and chemical properties of planetary systems around nearby stars and of our own, and investigate the potential for life in those systems. Webb will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will conclude the talk with a description of recent technical progress in the construction of the observatory.
The NASA Spitzer Space Telescope.
Gehrz, R D; Roellig, T L; Werner, M W; Fazio, G G; Houck, J R; Low, F J; Rieke, G H; Soifer, B T; Levine, D A; Romana, E A
2007-01-01
The National Aeronautics and Space Administration's Spitzer Space Telescope (formerly the Space Infrared Telescope Facility) is the fourth and final facility in the Great Observatories Program, joining Hubble Space Telescope (1990), the Compton Gamma-Ray Observatory (1991-2000), and the Chandra X-Ray Observatory (1999). Spitzer, with a sensitivity that is almost three orders of magnitude greater than that of any previous ground-based and space-based infrared observatory, is expected to revolutionize our understanding of the creation of the universe, the formation and evolution of primitive galaxies, the origin of stars and planets, and the chemical evolution of the universe. This review presents a brief overview of the scientific objectives and history of infrared astronomy. We discuss Spitzer's expected role in infrared astronomy for the new millennium. We describe pertinent details of the design, construction, launch, in-orbit checkout, and operations of the observatory and summarize some science highlights from the first two and a half years of Spitzer operations. More information about Spitzer can be found at http://spitzer.caltech.edu/.
QUIJOTE telescope design and fabrication
Gomez, Alberto; Murga, Gaizka; Etxeita, Borja; Sanquirce, Rubén; Rebolo, Rafael; Rubiño-Martin, Jose Alberto; Herreros, José-Miguel; Hoyland, Roger; Gomez, Francisca; Génova-Santos, Ricardo T.; Piccirillo, Lucio; Maffei, Bruno; Watson, Robert
2010-07-01
The QUIJOTE CMB experiment aims to characterize the polarization of the CMB in the frequency range 10-30 GHz and large angular scales. It will be installed in the Teide Observatory, following the projects that the Anisotropy of the Cosmic Microwave Background group has developed in the past (Tenerife experiment, IAC-Bartol experiment...) and is running at the present time (VSA, Cosmosomas). The QUIJOTE CMB experiment will consist of two telescopes which will be installed inside a unique enclosure, which is already constructed. The layout of both telescopes is based on an altazimuth mount supporting a primary and a secondary mirror disposed in a offset Gregorian Dragon scheme. The use of industrial-like fabrication techniques, such as sand-mould casting, CNC machining, and laser tracker measuring for alignment, provided the required performances for microwave observation. A fast-track construction scheme, altogether with the use of these fabrication techniques allowed designing and manufacturing the opto-mechanics of the telescope in 14 months prior to delivery for final start-up in December 2008.
Academic Training: Deep Space Telescopes
Françoise Benz
2006-01-01
2005-2006 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 20, 21, 22, 23, 24 February from 11:00 to 12:00 - Council Chamber on 20, 21, 23, 24 February, TH Auditorium, bldg 4 - 3-006, on 22 February Deep Space Telescopes G. BIGNAMI / CNRS, Toulouse, F & Univ. di Pavia, I The short series of seminars will address results and aims of current and future space astrophysics as the cultural framework for the development of deep space telescopes. It will then present such new tools, as they are currently available to, or imagined by, the scientific community, in the context of the science plans of ESA and of all major world space agencies. Ground-based astronomy, in the 400 years since Galileo's telescope, has given us a profound phenomenological comprehension of our Universe, but has traditionally been limited to the narrow band(s) to which our terrestrial atmosphere is transparent. Celestial objects, however, do not care about our limitations, and distribute most of the information about their physics thro...
Building the Green Bank Telescope
Kellermann, Kenneth I.
2017-01-01
In a previous presentation, I reported on how the freak collapse of the NRAO 300-ft transit radio telescope led to the inclusion of $75 million for a new radio telescope in the 1989 Congressional Emergency Supplemental Appropriations Act. But, this was only the beginning. NRAO was faced with challenging specifications and an unworkable schedule, but there was no design and no project team. Only one bid was even close to the Congressional appropriation. In an attempt to meet the unrealistic antenna delivery date, the contractor started construction of the foundation and fabrication of antenna members before the design was finished, leading to retrofits, redesign, and multiple delays. The antenna contractor was twice sold to other companies leading to further delays and cost escalation. In order to recoup their mounting losses, the new owners sued NRAO for $29 million for claimed design changes, and NRAO countersued demanding to be reimbursed for added project management costs and lost scientific data resulting from the seven-year delay in the completion of the telescope. Legal fees and a small net award in favor of the contractor left NRAO and the NSF with a nine million dollar bill which NSF handled by an innovative accounting adjustment.
Educational activities with the Faulkes Telescopes
Roberts, S.; Roche, P.; Ross, R.
2008-06-01
Las Cumbres Observatory Global Telescope Network (LCOGTN) will eventually provide access to a global network of robotic telescopes for research-based science education. Here we present the educational projects that have been undertaken using the 2-m Faulkes Telescopes in Hawaii and Australia in both the UK and Europe. These include themed observing days in which schools collaborate in their telescope sessions, the development of science portals where schools can upload and share their telescope data, and other innovative projects. Public access to these facilities will increase as IYA2009 approaches.
Hard X-ray Modulation Telescope
Institute of Scientific and Technical Information of China (English)
LU Fangjun
2011-01-01
The Hard X-ray Modulation Telescope （HXMT） will be China＇s first astronomical satellite. On board HXMT there are three kinds of slat-collimated telescopes, the High Energy X-ray Telescope （HE, 20-250 keV, 5000 cm^2）, the Medium Energy X-ray Telescope （ME, 5-30 keV, 952 cm^2）, and the Low Energy X-ray Telescope （LE, 1-15 keV, 384 cm^2）.