International Nuclear Information System (INIS)
Macfarlane, A J; Pfeiffer, Hendryk
2003-01-01
The uniformity, for the family of exceptional Lie algebras g, of the decompositions of the powers of their adjoint representations is now well known for powers up to four. The paper describes an extension of this uniformity for the totally antisymmetrized nth powers up to n = 9, identifying families of representations with integer eigenvalues 5, ..., 9 for the quadratic Casimir operator, in each case providing a formula for the dimensions of the representations in the family as a function of D = dim g. This generalizes previous results for powers j and Casimir eigenvalues j, j ≤ 4. Many intriguing, perhaps puzzling, features of the dimension formulae are discussed and the possibility that they may be valid for a wider class of not necessarily simple Lie algebras is considered
International Nuclear Information System (INIS)
Scheunert, M.
1982-10-01
The generators of the algebras under consideration can be written in a canonical two-index form and hence the associated standard seuqence of Casimir elements can be constructed. Following the classical approach by Perelomov and Popov, we obtain the eigenvalues of these Casimir elements in an arbitrary highest weight module by calculating the corresponding generating functions. (orig.)
International Nuclear Information System (INIS)
Campoamor-Stursberg, R
2008-01-01
We show that the Inoenue-Wigner contraction naturally associated to a reduction chain s implies s' of semisimple Lie algebras induces a decomposition of the Casimir operators into homogeneous polynomials, the terms of which can be used to obtain additional mutually commuting missing label operators for this reduction. The adjunction of these scalars that are no more invariants of the contraction allow to solve the missing label problem for those reductions where the contraction provides an insufficient number of labelling operators.
International Nuclear Information System (INIS)
Le Van Hop.
1989-12-01
The combinatorics computation is used to describe the Casimir operators of the symplectic Lie Algebra. This result is applied for determining the Center of the enveloping Algebra of the semidirect Product of the Heisenberg Lie Algebra and the symplectic Lie Algebra. (author). 10 refs
Energy Technology Data Exchange (ETDEWEB)
Torres-Guzman, Jose C [Centro de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico); Mochan, W Luis [Centro de Ciencias FIsicas, Universidad Nacional Autonoma de Mexico, Apartado Postal 48-3, 62251 Cuernavaca, Morelos (Mexico)
2006-05-26
We develop a formalism for the calculation of the flow of angular momentum carried by the fluctuating electromagnetic field within a cavity bounded by two flat anisotropic materials. By generalizing a procedure employed recently for the calculation of the Casimir force between arbitrary materials, we obtain an expression for the torque between anisotropic plates in terms of their reflection amplitude matrices. We evaluate the torque in 1D for ideal and dispersive model materials.
A Gedanken spacecraft that operates using the quantum vacuum (Dynamic Casimir effect)
Maclay, G. Jordan; Forward, Robert L.
2003-01-01
Conventional rockets are not a suitable technology for deep space missions. Chemical rockets require a very large weight of propellant, travel very slowly compared to light speed, and require significant energy to maintain operation over periods of years. For example, the 722 kg Voyager spacecraft required 13,600 kg of propellant to launch and would take about 80,000 years to reach the nearest star, Proxima Centauri, about 4.3 light years away. There have been various attempts at developing i...
Xu, Jun; Klimchitskaya, G. L.; Mostepanenko, V. M.; Mohideen, U.
2018-03-01
It is well known that residual electrostatic forces create significant difficulties in precise measurements of the Casimir force and the wide use of Casimir-operated microdevices. We experimentally demonstrate that, with the help of Ar-ion cleaning of the surfaces, it is possible to make electrostatic effects negligibly small compared to the Casimir interaction. Our experimental setup consists of a dynamic atomic force microscope supplemented with an Ar-ion gun and argon reservoir. The residual potential difference between the Au-coated surfaces of a sphere and those of a plate was measured both before and after in situ Ar-ion cleaning. It is shown that this cleaning decreases the magnitude of the residual potential by up to an order of magnitude and makes it almost independent of the separation. The gradient of the Casimir force was measured using ordinary samples subjected to Ar-ion cleaning. The obtained results are shown to be in good agreement both with previous precision measurements using specially selected samples and with theoretical predictions of the Lifshitz theory. The conclusion is made that the suggested method of in situ Ar-ion cleaning is effective in reducing the electrostatic effects and therefore is a great resource for experiments on measuring the Casimir interaction and for Casimir-operated microdevices.
Nonlinear (Anharmonic Casimir Oscillator
Directory of Open Access Journals (Sweden)
Habibollah Razmi
2011-01-01
Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.
International Nuclear Information System (INIS)
Graham, N.; Jaffe, R.L.; Khemani, V.; Quandt, M.; Schroeder, O.; Weigel, H.
2004-01-01
Casimir forces are conventionally computed by analyzing the effects of boundary conditions on a fluctuating quantum field. Although this analysis provides a clean and calculationally tractable idealization, it does not always accurately capture the characteristics of real materials, which cannot constrain the modes of the fluctuating field at all energies. We study the vacuum polarization energy of renormalizable, continuum quantum field theory in the presence of a background field, designed to impose a Dirichlet boundary condition in a particular limit. We show that in two and three space dimensions, as a background field becomes concentrated on the surface on which the Dirichlet boundary condition would eventually hold, the Casimir energy diverges. This result implies that the energy depends in detail on the properties of the material, which are not captured by the idealized boundary conditions. This divergence does not affect the force between rigid bodies, but it does invalidate calculations of Casimir stresses based on idealized boundary conditions
Microscopic dynamical Casimir effect
Souza, Reinaldo de Melo e.; Impens, François; Neto, Paulo A. Maia
2018-03-01
We consider an atom in its ground state undergoing a nonrelativistic oscillation in free space. The interaction with the electromagnetic quantum vacuum leads to two effects to leading order in perturbation theory. When the mechanical frequency is larger than the atomic transition frequency, the dominant effect is the motion-induced transition to an excited state with the emission of a photon carrying the excess energy. We compute the angular distribution of emitted photons and the excitation rate. On the other hand, when the mechanical frequency is smaller than the transition frequency, the leading-order effect is the parametric emission of photon pairs, which constitutes the microscopic counterpart of the dynamical Casimir effect. We discuss the properties of the microscopic dynamical Casimir effect and build a connection with the photon production by an oscillating macroscopic metallic mirror.
Towards a Casimir Force Measurement between Micromachined Parallel Plate Structures
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Remco J. Wiegerink
2012-11-01
Full Text Available Ever since its prediction, experimental investigation of the Casimir force has been of great scientific interest. Many research groups have successfully attempted quantifying the force with different device geometries; however, measurement of the Casimir force between parallel plates with sub-micron separation distance is still a challenging task, since it becomes extremely difficult to maintain sufficient parallelism between the plates. The Casimir force can significantly influence the operation of micro devices and to realize reliable and reproducible devices it is necessary to understand and experimentally verify the influence of the Casimir force at sub-micron scale. In this paper, we present the design principle, fabrication and characterization of micromachined parallel plate structures that could allow the measurement of the Casimir force with tunable separation distance in the range of 100 to 1000 nm. Initially, a gold coated parallel plate structure is explored to measure the Casimir force, but also other material combinations could be investigated. Using gold-silicon eutectic bonding, a reliable approach to bond chips with integrated suspended plates together with a well-defined separation distance in the order of 1–2 μm is developed.
Casimir forces from a loop integral formulation
International Nuclear Information System (INIS)
Babington, James
2010-01-01
We reformulate the Casimir force between bodies in non-trivial background media. The force may be written in terms of loop variables, the loop being a curve around the scattering sites. A natural path ordering of exponentials takes place when a particular representation of the scattering centres is given. The basic object to be evaluated is a reduced (or abbreviated) classical pseudo-action that can be operator valued, and can be obtained from a classical path integral description.
Nonperturbative Dynamical Casimir Effect in Optomechanical Systems: Vacuum Casimir-Rabi Splittings
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Vincenzo Macrì
2018-02-01
Full Text Available We study the dynamical Casimir effect using a fully quantum-mechanical description of both the cavity field and the oscillating mirror. We do not linearize the dynamics, nor do we adopt any parametric or perturbative approximation. By numerically diagonalizing the full optomechanical Hamiltonian, we show that the resonant generation of photons from the vacuum is determined by a ladder of mirror-field vacuum Rabi splittings. We find that vacuum emission can originate from the free evolution of an initial pure mechanical excited state, in analogy with the spontaneous emission from excited atoms. By considering a coherent drive of the mirror, using a master-equation approach to take losses into account, we are able to study the dynamical Casimir effect for optomechanical coupling strengths ranging from weak to ultrastrong. We find that a resonant production of photons out of the vacuum can be observed even for mechanical frequencies lower than the cavity-mode frequency. Since high mechanical frequencies, which are hard to achieve experimentally, were thought to be imperative for realizing the dynamical Casimir effect, this result removes one of the major obstacles for the observation of this long-sought effect. We also find that the dynamical Casimir effect can create entanglement between the oscillating mirror and the radiation produced by its motion in the vacuum field, and that vacuum Casimir-Rabi oscillations can occur. Finally, we also show that all these findings apply not only to optomechanical systems, but also to parametric amplifiers operating in the fully quantum regime.
On the Casimir of the group ISL(n,R) and its algebraic decomposition
International Nuclear Information System (INIS)
Pecina-Cruz, J.N.
2005-01-01
In this paper, an explicit expression for the Casimir operator (or the Casimir invariant) of the inhomogeneous group ISL(n,R) in its enveloping algebra is proposed, which using contractions of the tensorial indices of the generating operators P ρ and E μ ν may be presented in the following [slightly more comprehensible as Eq. (1)] form. The Casimir is obtained by symmetrizing this expression. This tensor form is useful in the classification of particles in affine gravitational gauge theories; such as that based on ISL(4,R). It is also proven that the Casimir of ISL(n,R) can be decomposed in terms of the Casimirs of its little groups, a key point in the posterior construction of its irreducible representations
Graphene cantilever under Casimir force
Derras-Chouk, Amel; Chudnovsky, Eugene M.; Garanin, Dmitry A.; Jaafar, Reem
2018-05-01
The stability of graphene cantilever under Casimir attraction to an underlying conductor is investigated. The dependence of the instability threshold on temperature and flexural rigidity is obtained. Analytical work is supplemented by numerical computation of the critical temperature above which the graphene cantilever irreversibly bends down and attaches to the conductor. The geometry of the attachment and exfoliation of the graphene sheet is discussed. It is argued that graphene cantilever can be an excellent tool for precision measurements of the Casimir force.
Casimir effect for interacting fields
International Nuclear Information System (INIS)
Kay, B.S.
1982-01-01
The author discusses some recent work on the Casimir effect: that is the problem of renormalizing Tsub(μγ) on locally-flat space-times. That is on space-times which, while topologically non-trivial are locally Minkowskian - with vanishing local curvature. The author has developed a systematic method for calculating this Casimir effect for interacting fields to arbitrary order in perturbation theory - and for arbitrary components of Tsub(μγ) which he describes in general and then illustrates it by describing first order perturbation theory calculations for a lambdaphi 4 theory for the two models: the cylinder space-time and the parallel plates. (Auth.)
Thermal Fluctuations in Casimir Pistons
Lomnitz, M.; Villarreal, C.
2012-07-01
We present analytical and simple expressions to determine the free energy, internal energy, entropy, as well as the pressure acting at the interface of a perfectly conducting rectangular Casimir piston. We show that infrared divergencies linear in temperature become cancelled within the piston configuration, and show a continuous behavior consistent with intuitive expectations.
Archimedes force on Casimir apparatus
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Shevchenko V.
2016-01-01
Full Text Available The talk addresses a problem of Casimir apparatus in weak gravitational field, surrounded by a dense medium. The falling of the apparatus has to be governed by the equivalence principle, taking into account proper contributions to the weight of the apparatus from its material part and from distorted quantum fields. We discuss general ex pression for the corresponding force in terms of the effective action. By way of example we compute explicit expression for Archimedes force, acting on the Casimir apparatus of finite size, immersed into thermal bath of free scalar field. It is shown that besides universal term, proportional to the volume of the apparatus, there are non-universal quantum corrections, depending on the boundary conditions.
The Reality of Casimir Friction
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Kimball A. Milton
2016-04-01
Full Text Available For more than 35 years theorists have studied quantum or Casimir friction, which occurs when two smooth bodies move transversely to each other, experiencing a frictional dissipative force due to quantum electromagnetic fluctuations, which break time-reversal symmetry. These forces are typically very small, unless the bodies are nearly touching, and consequently such effects have never been observed, although lateral Casimir forces have been seen for corrugated surfaces. Partly because of the lack of contact with observations, theoretical predictions for the frictional force between parallel plates, or between a polarizable atom and a metallic plate, have varied widely. Here, we review the history of these calculations, show that theoretical consensus is emerging, and offer some hope that it might be possible to experimentally confirm this phenomenon of dissipative quantum electrodynamics.
Casimir Effect on the Worldline
Gies, Holger; Moyaerts, L; Gies, Holger; Langfeld, Kurt; Moyaerts, Laurent
2003-01-01
We develop a method to compute the Casimir effect for arbitrary geometries. The method is based on the string-inspired worldline approach to quantum field theory and its numerical realization with Monte-Carlo techniques. Concentrating on Casimir forces between rigid bodies induced by a fluctuating scalar field, we test our method with the parallel-plate configuration. For the experimentally relevant sphere-plate configuration, we study curvature effects quantitatively and perform a comparison with the ``proximity force approximation'', which is the standard approximation technique. Sizable curvature effects are found for a distance-to-curvature-radius ratio of a/R >~ 0.02. Our method is embedded in renormalizable quantum field theory with a controlled treatment of the UV divergencies. As a technical by-product, we develop various efficient algorithms for generating closed-loop ensembles with Gaussian distribution.
Casimir scaling and Yang-Mills glueballs
Hong, Deog Ki; Lee, Jong-Wan; Lucini, Biagio; Piai, Maurizio; Vadacchino, Davide
2017-12-01
We conjecture that in Yang-Mills theories the ratio between the ground-state glueball mass squared and the string tension is proportional to the ratio of the eigenvalues of quadratic Casimir operators in the adjoint and the fundamental representations. The proportionality constant depends on the dimension of the space-time only, and is henceforth universal. We argue that this universality, which is supported by available lattice results, is a direct consequence of area-law confinement. In order to explain this universal behavior, we provide three analytical arguments, based respectively on a Bethe-Salpeter analysis, on the saturation of the scale anomaly by the lightest scalar glueball and on QCD sum rules, commenting on the underlying assumptions that they entail and on their physical implications.
Mode Contributions to the Casimir Effect
Intravaia, F.; Henkel, C.
2010-04-01
Applying a sum-over-modes approach to the Casimir interaction between two plates with finite conductivity, we isolate and study the contributions of surface plasmons and Foucault (eddy current) modes. We show in particular that for the TE-polarization eddy currents provide a repulsive force that cancels, at high temperatures, the Casimir free energy calculated with the plasma model.
Casimir interaction between spheres in (D+1)-dimensional Minkowski spacetime
Energy Technology Data Exchange (ETDEWEB)
Teo, L.P. [Department of Applied Mathematics, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan (Malaysia)
2014-05-06
We consider the Casimir interaction between two spheres in (D+1)-dimensional Minkowski spacetime due to the vacuum fluctuations of scalar fields. We consider combinations of Dirichlet and Neumann boundary conditions. The TGTG formula of the Casimir interaction energy is derived. The computations of the T matrices of the two spheres are straightforward. To compute the two G matrices, known as translation matrices, which relate the hyper-spherical waves in two spherical coordinate frames differ by a translation, we generalize the operator approach employed in R.C. Wittman, Spherical Wave Operators and the Translation Formulas, IEEE Trans. Antennas Propag. 36 (1988) 1078. . The result is expressed in terms of an integral over Gegenbauer polynomials. In contrast to the D=3 case, we do not re-express the integral in terms of 3j-symbols and hyper-spherical waves, which in principle, can be done but does not simplify the formula. Using our expression for the Casimir interaction energy, we derive the large separation and small separation asymptotic expansions of the Casimir interaction energy. In the large separation regime, we find that the Casimir interaction energy is of order L{sup −2D+3}, L{sup −2D+1} and L{sup −2D−1} respectively for Dirichlet-Dirichlet, Dirichlet-Neumann and Neumann-Neumann boundary conditions, where L is the center-to-center distance of the two spheres. In the small separation regime, we confirm that the leading term of the Casimir interaction agrees with the proximity force approximation, which is of order d{sup −((D+1)/2)}, where d is the distance between the two spheres. Another main result of this work is the analytic computations of the next-to-leading order term in the small separation asymptotic expansion. This term is computed using careful order analysis as well as perturbation method. In the case the radius of one of the sphere goes to infinity, we find that the results agree with the one we derive for sphere-plate configuration
Casimir scaling and YangâMills glueballs
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Deog Ki Hong
2017-12-01
Full Text Available We conjecture that in YangâMills theories the ratio between the ground-state glueball mass squared and the string tension is proportional to the ratio of the eigenvalues of quadratic Casimir operators in the adjoint and the fundamental representations. The proportionality constant depends on the dimension of the space-time only, and is henceforth universal. We argue that this universality, which is supported by available lattice results, is a direct consequence of area-law confinement. In order to explain this universal behavior, we provide three analytical arguments, based respectively on a BetheâSalpeter analysis, on the saturation of the scale anomaly by the lightest scalar glueball and on QCD sum rules, commenting on the underlying assumptions that they entail and on their physical implications. Keywords: Glueballs, YangâMills theories, Confinement, Casimir scaling
Supersymmetry Breaking Casimir Warp Drive
Obousy, Richard K.; Cleaver, Gerald
2007-01-01
This paper utilizes a recent model which relates the cosmological constant to the Casimir energy of the extra dimensions in brane-world theories. The objective of this paper is to demonstrate that, given some sufficiently advanced civilization with the ability to manipulate the radius of the extra dimension, a local adjustment of the cosmological constant could be created. This adjustment would facilitate an expansion/contraction of the spacetime around a spacecraft creating an exotic form of field-propulsion. This idea is analogous to the Alcubierre bubble, but differs entirely in the approach, utilizing the physics of higher dimensional quantum field theory, instead of general relativity.
Theoretical ingredients of a Casimir analog computer.
Rodriguez, Alejandro W; McCauley, Alexander P; Joannopoulos, John D; Johnson, Steven G
2010-05-25
We derive a correspondence between the contour integration of the Casimir stress tensor in the complex-frequency plane and the electromagnetic response of a physical dissipative medium in a finite real-frequency bandwidth. The consequences of this correspondence are at least threefold: First, the correspondence makes it easier to understand Casimir systems from the perspective of conventional classical electromagnetism, based on real-frequency responses, in contrast to the standard imaginary-frequency point of view based on Wick rotations. Second, it forms the starting point of finite-difference time-domain numerical techniques for calculation of Casimir forces in arbitrary geometries. Finally, this correspondence is also key to a technique for computing quantum Casimir forces at micrometer scales using antenna measurements at tabletop (e.g., centimeter) scales, forming a type of analog computer for the Casimir force. Superficially, relationships between the Casimir force and the classical electromagnetic Green's function are well known, so one might expect that any experimental measurement of the Green's function would suffice to calculate the Casimir force. However, we show that the standard forms of this relationship lead to infeasible experiments involving infinite bandwidth or exponentially growing fields, and a fundamentally different formulation is therefore required.
Casimir Interaction from Magnetically Coupled Eddy Currents
Intravaia, Francesco; Henkel, Carsten
2009-09-01
We study the quantum and thermal fluctuations of eddy (Foucault) currents in thick metallic plates. A Casimir interaction between two plates arises from the coupling via quasistatic magnetic fields. As a function of distance, the relevant eddy current modes cross over from a quantum to a thermal regime. These modes alone reproduce previously discussed thermal anomalies of the electromagnetic Casimir interaction between good conductors. In particular, they provide a physical picture for the Casimir entropy whose nonzero value at zero temperature arises from a correlated, glassy state.
The Casimir effect: medium and geometry
International Nuclear Information System (INIS)
Marachevsky, Valery N
2012-01-01
Theory of the Casimir effect is presented in several examples. Casimir–Polder-type formulas, Lifshitz theory and theory of the Casimir effect for two gratings separated by a vacuum slit are derived. Equations for the electromagnetic field in the presence of a medium and dispersion are discussed. The Casimir effect for systems with a layer of 2 + 1 fermions is studied. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker's 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (paper)
Casimir force in noncommutative Randall-Sundrum models revisited
International Nuclear Information System (INIS)
Teo, L. P.
2010-01-01
We propose another method to compute the Casimir force in noncommutative Randall-Sundrum braneworld model considered by K. Nouicer and Y. Sabri, Phys. Rev. D 80, 086013 (2009). recently. Our method can be used to compute the Casimir force to any order in the noncommutative parameter. Contrary to the claim made by K. Nouicer and Y. Sabri that repulsive Casimir force can appear in the first order approximation, we show that the Casimir force is always attractive at any order of approximation.
Detecting chameleons through Casimir force measurements
International Nuclear Information System (INIS)
Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine; Shaw, Douglas; Mota, David F.
2007-01-01
The best laboratory constraints on strongly coupled chameleon fields come not from tests of gravity per se but from precision measurements of the Casimir force. The chameleonic force between two nearby bodies is more akin to a Casimir-like force than a gravitational one: The chameleon force behaves as an inverse power of the distance of separation between the surfaces of two bodies, just as the Casimir force does. Additionally, experimental tests of gravity often employ a thin metallic sheet to shield electrostatic forces; however, this sheet masks any detectable signal due to the presence of a strongly coupled chameleon field. As a result of this shielding, experiments that are designed to specifically test the behavior of gravity are often unable to place any constraint on chameleon fields with a strong coupling to matter. Casimir force measurements do not employ a physical electrostatic shield and as such are able to put tighter constraints on the properties of chameleons fields with a strong matter coupling than tests of gravity. Motivated by this, we perform a full investigation on the possibility of testing chameleon models with both present and future Casimir experiments. We find that present-day measurements are not able to detect the chameleon. However, future experiments have a strong possibility of detecting or rule out a whole class of chameleon models
Casimir effect in spherical shells
International Nuclear Information System (INIS)
Ruggiero, J.R.
1985-01-01
The analytic regularization method is applied to study the Casimir effect for spherical cavities. Although many works have been presented in the past few years, problems related to the elimination of the regulator parameter still remain. A way to calculate the zero point energy of a perfectly conducting spherical shell which is a miscellaneous of those presented early is here proposed, How a cancelation of divergent terms occurs and how a finite parte is obtained after the elimination of the regulator parameter is shown. As a by-product the zero point energy of the interior vibration modes is obtained and this has some relevance to the quarks bag model. This relev ance is also discussed. The calculation of the energy fom the density view is also discussed. Some works in this field are criticized. The logarithmic divergent terms in the zero point energy are studied when the interior and exterior of the sphere are considered as a medium not dispersive and characterized by a dielectric constants ε 1 and ε 2 and peermeability constants μ 1 and μ 2 respectivelly. The logarithmic divergent terms are not present in the case of ε i μ i =K, with K some constant and i=1,2. (author) [pt
Gravitational Casimir-Polder effect
Hu, Jiawei; Yu, Hongwei
2017-04-01
The interaction due to quantum gravitational vacuum fluctuations between a gravitationally polarizable object modelled as a two-level system and a gravitational boundary is investigated. This quantum gravitational interaction is found to be position-dependent, which induces a force in close analogy to the Casimir-Polder force in the electromagnetic case. For a Dirichlet boundary, the quantum gravitational potential for the polarizable object in its ground-state is shown to behave like z-5 in the near zone, and z-6 in the far zone, where z is the distance to the boundary. For a concrete example, where a Bose-Einstein condensate is taken as a gravitationally polarizable object, the relative correction to the radius of the BEC caused by fluctuating quantum gravitational waves in vacuum is found to be of order 10-21. Although the correction is far too small to observe in comparison with its electromagnetic counterpart, it is nevertheless of the order of the gravitational strain caused by a recently detected black hole merger on the arms of the LIGO.
Johnson noise and the thermal Casimir effect
International Nuclear Information System (INIS)
Bimonte, Giuseppe
2007-01-01
We study the thermal interaction between two nearby thin metallic wires, at finite temperature. It is shown that the Johnson currents in the wires give rise, via inductive coupling, to a repulsive force between them. This thermal interaction exhibits all the puzzling features found recently in the thermal Casimir effect for lossy metallic plates, suggesting that the physical origin of the difficulties encountered in the Casimir problem resides in the inductive coupling between the Johnson currents inside the plates. We show that in our simple model all puzzles are resolved if account is taken of capacitive effects associated with the end points of the wires. Our findings suggest that capacitive finite-size effects may play an important role in the resolution of the analogous problems met in the thermal Casimir effect
Oscillating Casimir force between two slabs in a Fermi sea
DEFF Research Database (Denmark)
Li-Wei, Chen; Guo-Zhen, Su; Jin-Can, Chen
2012-01-01
The Casimir effect for two parallel slabs immersed in an ideal Fermi sea is investigated at both zero and nonzero temperatures. It is found that the Casimir effect in a Fermi gas is distinctly different from that in an electromagnetic field or a massive Bose gas. In contrast to the familiar result...... that the Casimir force decreases monotonically with the increase of the separation L between two slabs in an electromagnetic field and a massive Bose gas, the Casimir force in a Fermi gas oscillates as a function of L. The Casimir force can be either attractive or repulsive, depending sensitively on the magnitude...... of L. In addition, it is found that the amplitude of the Casimir force in a Fermi gas decreases with the increase of the temperature, which also is contrary to the case in a Bose gas, since the bosonic Casimir force increases linearly with the increase of the temperature in the region T
Casimir elements of epsilon Lie algebras
International Nuclear Information System (INIS)
Scheunert, M.
1982-10-01
The classical framework for investigating the Casimir elements of a Lie algebra is generalized to the case of an epsilon Lie algebra L. We construct the standard L-module isomorphism of the epsilon-symmetric algebra of L onto its enveloping algebra and we introduce the Harish-Chandra homomorphism. In case the generators of L can be written in a canonical two-index form, we construct the associated standard sequence of Casimir elements and derive a formula for their eigenvalues in an arbitrary highest weight module. (orig.)
Repulsive electromagnetic stresses in the Casimir piston
García, L.; González, L. E.; Lomnitz, M.; Villarreal, C.
2008-01-01
This manuscript has been withdrawn, since the authors have detected numerical inaccuracies that invalidate their main results concerning the existence of repulsive Casimir forces within a rectangular piston. Formulas presented in the manuscript keep still valid. The authors deeply apologize for this mistake.
Halving the Casimir force with Conductive Oxides
de Man, S.P.J.; Heeck, K.; Wijngaarden, R.J.; Iannuzzi, D.
2009-01-01
The possibility to modify the strength of the Casimir effect by tailoring the dielectric functions of the interacting surfaces is regarded as a unique opportunity in the development of micro- and nanoelectromechanical systems. In air, however, one expects that, unless noble metals are used, the
Chaotic behavior in Casimir oscillators: A case study for phase-change materials.
Tajik, Fatemeh; Sedighi, Mehdi; Khorrami, Mohammad; Masoudi, Amir Ali; Palasantzas, George
2017-10-01
Casimir forces between material surfaces at close proximity of less than 200 nm can lead to increased chaotic behavior of actuating devices depending on the strength of the Casimir interaction. We investigate these phenomena for phase-change materials in torsional oscillators, where the amorphous to crystalline phase transitions lead to transitions between high and low Casimir force and torque states, respectively, without material compositions. For a conservative system bifurcation curve and Poincare maps analysis show the absence of chaotic behavior but with the crystalline phase (high force-torque state) favoring more unstable behavior and stiction. However, for a nonconservative system chaotic behavior can take place introducing significant risk for stiction, which is again more pronounced for the crystalline phase. The latter illustrates the more general scenario that stronger Casimir forces and torques increase the possibility for chaotic behavior. The latter is making it impossible to predict whether stiction or stable actuation will occur on a long-term basis, and it is setting limitations in the design of micronano devices operating at short-range nanoscale separations.
Selective decay by Casimir dissipation in inviscid fluids
International Nuclear Information System (INIS)
Gay-Balmaz, François; Holm, Darryl D
2013-01-01
The problem of parameterizing the interactions of larger scales and smaller scales in fluid flows is addressed by considering a property of two-dimensional (2D) incompressible turbulence. The property we consider is selective decay, in which a Casimir of the ideal formulation (enstrophy in 2D flows, helicity in three-dimensional flows) decays in time, while the energy stays essentially constant. This paper introduces a mechanism that produces selective decay by enforcing Casimir dissipation in fluid dynamics. This mechanism turns out to be related in certain cases to the numerical method of anticipated vorticity discussed in Sadourny and Basdevant (1981 C. R. Acad. Sci. Paris 292 1061–4, 1985 J. Atm. Sci. 42 1353–63). Several examples are given and a general theory of selective decay is developed that uses the Lie–Poisson structure of the ideal theory. A scale-selection operator allows the resulting modifications of the fluid motion equations to be interpreted in several examples as parametrizing the nonlinear, dynamical interactions between disparate scales. The type of modified fluid equation systems derived here may be useful in modelling turbulent geophysical flows where it is computationally prohibitive to rely on the slower, indirect effects of a realistic viscosity, such as in large-scale, coherent, oceanic flows interacting with much smaller eddies. (paper)
Dynamical Casimir effect with semi-transparent mirrors, and cosmology
International Nuclear Information System (INIS)
Elizalde, Emilio
2008-01-01
After reviewing some essential features of the Casimir effect and, specifically, of its regularization by zeta function and Hadamard methods, we consider the dynamical Casimir effect (or Fulling-Davies theory), where related regularization problems appear, with a view to an experimental verification of this theory. We finish with a discussion of the possible contribution of vacuum fluctuations to dark energy, in a Casimir-like fashion, that might involve the dynamical version
Casimir apparatuses in a weak gravitational field
DEFF Research Database (Denmark)
Bimonte, Giuseppe; Calloni, Enrico; Esposito, Giampiero
2009-01-01
We review and assess a part of the recent work on Casimir apparatuses in the weak gravitational field of the Earth. For a free, real massless scalar field subject to Dirichlet or Neumann boundary conditions on the parallel plates, the resulting regularized and renormalized energy-momentum tensor...... is covariantly conserved, while the trace anomaly vanishes if the massless field is conformally coupled to gravity. Conformal coupling also ensures a finite Casimir energy and finite values of the pressure upon parallel plates. These results have been extended to an electromagnetic field subject to perfect...... conductor (hence idealized) boundary conditions on parallel plates, by various authors. The regularized and renormalized energy-momentum tensor has beene valuated up to second order in the gravity acceleration. In both the scalar and the electromagnetic case, studied to first order in the gravity...
Casimir energy for a piecewise uniform string
International Nuclear Information System (INIS)
Brevik, I.; Nielsen, H.B.
1989-07-01
The Casimir energy for the transverse oscillations of a piecewise uniform closed string is calculated. The string consists of two parts I and II, endowed in general with different tensions and mass densities, although adjusted in such a way that the velocity of sound always equals the velocity of light. The dispersion equation is worked out under general conditions, and the frequency spectrum is determined in special cases. When the ratio L II /L I between the string lengths is an integer, it is in principle possible to determine the frequency spectrum through solving algebraic equations of increasingly high degree. The Casimir energy relative to the uniform string is in general found to be negative, although in the special case L I =L II the energy is equal to zero. Delicate points in the regularization procedure are discussed; they point toward an anomaly in the theory. (orig.)
Casimir interactions between graphene sheets and metamaterials
International Nuclear Information System (INIS)
Drosdoff, D.; Woods, Lilia M.
2011-01-01
The Casimir force between graphene sheets and metamaterials is studied. Theoretical results based on the Lifshitz theory for layered, planar, two-dimensional systems in media are presented. We consider graphene-graphene, graphene-metamaterial, and metal-graphene-metamaterial configurations. We find that quantum effects of the temperature-dependent force are not apparent until the submicron range. In contrast to results with bulk dielectric and bulk metallic materials, no Casimir repulsion is found when graphene is placed on top of a magnetically active metamaterial substrate, regardless of the strength of the low-frequency magnetic response. In the case of the metal-graphene-metamaterial setting, repulsion between the metamaterial and the metal-graphene system is possible only when the dielectric response from the metal contributes significantly.
Casimir Energy, Extra Dimensions and Exotic Propulsion
Obousy, R.; Saharian, A.
It is well known that the Casimir effect is an excellent candidate for the stabilization of the extra dimensions. It has also been suggested that the Casimir effect in higher dimensions may be the underlying phenomenon that is responsible for the dark energy which is currently driving the accelerated expansion of the universe. In this paper we suggest that, in principle, it may be possible to directly manipulate the size of an extra dimension locally using Standard Model fields in the next generation of particle accelerators. This adjustment of the size of the higher dimension could serve as a technological mechanism to locally adjust the dark energy density and change the local expansion of spacetime. This idea holds tantalizing possibilities in the context of exotic spacecraft propulsion.
Casimir pistons with general boundary conditions
Directory of Open Access Journals (Sweden)
Guglielmo Fucci
2015-02-01
Full Text Available In this work we analyze the Casimir energy and force for a scalar field endowed with general self-adjoint boundary conditions propagating in a higher dimensional piston configuration. The piston is constructed as a direct product I×N, with I=[0,L]⊂R and N a smooth, compact Riemannian manifold with or without boundary. The study of the Casimir energy and force for this configuration is performed by employing the spectral zeta function regularization technique. The obtained analytic results depend explicitly on the spectral zeta function associated with the manifold N and the parameters describing the general boundary conditions imposed. These results are then specialized to the case in which the manifold N is a d-dimensional sphere.
On Casimir elements of simple Lie algebras
International Nuclear Information System (INIS)
El Houari, M.
1996-08-01
In this letter, we recall briefly the generalized Casimir elements of a finite dimensional Lie algebra. We specify those of orders two and three: when the Lie algebra is simple (even semisimple), we begin by normalizing the former (the quadratic), and then we study some actions of the latter (the cubic). In particular, we introduce a graphical formalism, translating rigorously the tensorial calculus. This allows us to prove the main theorem in a graphic theoretic manner. (author). 11 refs, 1 tab
Casimir-Polder interaction in second quantization
Energy Technology Data Exchange (ETDEWEB)
Schiefele, Juergen
2011-03-21
The Casimir-Polder interaction between a single neutral atom and a nearby surface, arising from the (quantum and thermal) fluctuations of the electromagnetic field, is a cornerstone of cavity quantum electrodynamics (cQED), and theoretically well established. Recently, Bose-Einstein condensates (BECs) of ultracold atoms have been used to test the predictions of cQED. The purpose of the present thesis is to upgrade single-atom cQED with the many-body theory needed to describe trapped atomic BECs. Tools and methods are developed in a second-quantized picture that treats atom and photon fields on the same footing. We formulate a diagrammatic expansion using correlation functions for both the electromagnetic field and the atomic system. The formalism is applied to investigate, for BECs trapped near surfaces, dispersion interactions of the van der Waals-Casimir-Polder type, and the Bosonic stimulation in spontaneous decay of excited atomic states. We also discuss a phononic Casimir effect, which arises from the quantum fluctuations in an interacting BEC. (orig.)
Casimir-Polder interaction in second quantization
International Nuclear Information System (INIS)
Schiefele, Juergen
2011-01-01
The Casimir-Polder interaction between a single neutral atom and a nearby surface, arising from the (quantum and thermal) fluctuations of the electromagnetic field, is a cornerstone of cavity quantum electrodynamics (cQED), and theoretically well established. Recently, Bose-Einstein condensates (BECs) of ultracold atoms have been used to test the predictions of cQED. The purpose of the present thesis is to upgrade single-atom cQED with the many-body theory needed to describe trapped atomic BECs. Tools and methods are developed in a second-quantized picture that treats atom and photon fields on the same footing. We formulate a diagrammatic expansion using correlation functions for both the electromagnetic field and the atomic system. The formalism is applied to investigate, for BECs trapped near surfaces, dispersion interactions of the van der Waals-Casimir-Polder type, and the Bosonic stimulation in spontaneous decay of excited atomic states. We also discuss a phononic Casimir effect, which arises from the quantum fluctuations in an interacting BEC. (orig.)
Temperature dependence of the Casimir effect
Energy Technology Data Exchange (ETDEWEB)
Brevik, I [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway); Aarseth, J B [Department of Structural Engineering, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)
2006-05-26
In view of the increasing accuracy of Casimir experiments, there is a need for performing accurate theoretical calculations. Using accurate experimental data for the permittivities we present, via the Lifshitz formula applied to the standard Casimir setup with two parallel plates, accurate theoretical results in the case of the metals Au, Cu and Al. Both similar and dissimilar cases are considered. Concentrating in particular on the finite temperature effect, we show how the Casimir pressure varies with separation for three different temperatures, T = {l_brace}1, 300, 350{r_brace}K. The metal surfaces are taken to be perfectly plane. The experimental data for the permittivities generally yield results that are in a good agreement with those calculated from the Drude relation with finite relaxation frequency. We give the results in a tabular form, in order to facilitate the assessment of the temperature correction which is on the 1% level. We emphasize two points: (i) the most promising route for a definite experimental verification of the finite temperature correction appears to be to concentrate on the case of large separations (optimum around 2 {mu}m); and (ii) there is no conflict between the present kind of theory and the Nernst theorem in thermodynamics.
Symmetries and casimir of an extended classical long wave system
Indian Academy of Sciences (India)
We discuss the construction of a sequence of negative ranking symmetries through the property of uniformity in rank. More interestingly, we obtain the conserved quantities directly from the casimir of Poisson pencil. Keywords. Dispersionless equations; symmetries; casimir; conserved quantities. PACS Nos 02.30.Ik; 02.30.
Repulsive Casimir force at zero and finite temperature
International Nuclear Information System (INIS)
Lim, S C; Teo, L P
2009-01-01
We study the zero and finite temperature Casimir force acting on a perfectly conducting piston with arbitrary cross section moving inside a closed cylinder with infinitely permeable walls. We show that at any temperature, the Casimir force always tends to move the piston away from the walls and toward its equilibrium position. In the case of a rectangular piston, exact expressions for the Casimir force are derived. In the high-temperature regime, we show that the leading term of the Casimir force is linear in temperature and therefore the Casimir force has a classical limit. Due to duality, all these results also hold for an infinitely permeable piston moving inside a closed cylinder with perfectly conducting walls.
International Nuclear Information System (INIS)
Ton-That, Tuong
2005-01-01
In a previous paper we gave a generalization of the notion of Casimir invariant differential operators for the infinite-dimensional Lie groups GL ∞ (C) (or equivalently, for its Lie algebra gj ∞ (C)). In this paper we give a generalization of the Casimir invariant differential operators for a class of infinite-dimensional Lie groups (or equivalently, for their Lie algebras) which contains the infinite-dimensional complex classical groups. These infinite-dimensional Lie groups, and their Lie algebras, are inductive limits of finite-dimensional Lie groups, and their Lie algebras, with some additional properties. These groups or their Lie algebras act via the generalized adjoint representations on projective limits of certain chains of vector spaces of universal enveloping algebras. Then the generalized Casimir operators are the invariants of the generalized adjoint representations. In order to be able to explicitly compute the Casimir operators one needs a basis for the universal enveloping algebra of a Lie algebra. The Poincare-Birkhoff-Witt (PBW) theorem gives an explicit construction of such a basis. Thus in the first part of this paper we give a generalization of the PBW theorem for inductive limits of Lie algebras. In the last part of this paper a generalization of the very important theorem in representation theory, namely the Chevalley-Racah theorem, is also discussed
A microscopic approach to Casimir and Casimir-Polder forces between metallic bodies
Barcellona, Pablo; Passante, Roberto
2015-04-01
We consider the Casimir-Polder interaction energy between a metallic nanoparticle and a metallic plate, as well as the Casimir interaction energy between two macroscopic metal plates, in terms of the many-body dispersion interactions between their constituents. Expressions for two- and three-body dispersion interactions between the microscopic parts of a real metal are first obtained, both in the retarded and non-retarded limits. These expressions are then used to evaluate the overall two- and three-body contributions to the macroscopic Casimir-Polder and Casimir force, and to compare them with each other, for the two following geometries: metal nanoparticle/half-space and half-space/half-space, where all the materials are assumed perfect conductors. The above evaluation is obtained by summing up the contributions from the microscopic constituents of the bodies (metal nanoparticles). In the case of nanoparticle/half-space, our results fully agree with those that can be extracted from the corresponding macroscopic results, and explicitly show the non-applicability of the pairwise approximation for the geometry considered. In both cases, we find that, while the overall two-body contribution yields an attractive force, the overall three-body contribution is repulsive. Also, they turn out to be of the same order, consistently with the known non applicability of the pairwise approximation. The issue of the rapidity of convergence of the many-body expansion is also briefly discussed.
International Nuclear Information System (INIS)
Chaichian, M.; Tureanu, A.; Demichev, A.; Presnajder, P.; Sheikh-Jabbari, M.M.
2001-02-01
After discussing the peculiarities of quantum systems on noncommutative (NC) spaces with nontrivial topology and the operator representation of the *-product on them, we consider the Aharonov-Bohm and Casimir effects for such spaces. For the case of the Aharonov-Bohm effect, we have obtained an explicit expression for the shift of the phase, which is gauge invariant in the NC sense. The Casimir energy of a field theory on a NC cylinder is divergent, while it becomes finite on a torus, when the dimensionless parameter of noncommutativity is a rational number. The latter corresponds to a well-defined physical picture. Certain distinctions from other treatments based on a different way of taking the noncommutativity into account are also discussed. (author)
Sign and other aspects of semiclassical Casimir energies
International Nuclear Information System (INIS)
Schaden, Martin
2006-01-01
The Casimir energy of a massless scalar field is semiclassically given by contributions due to classical periodic rays. The required subtractions in the spectral density are determined explicitly. The semiclassical Casimir energies so defined coincide with those of zeta function regularization in the cases studied. Poles in the analytic continuation of zeta function regularization are related to nonuniversal subtractions in the spectral density. The sign of the Casimir energy of a scalar field on a smooth manifold is estimated by the sign of the contribution due to the shortest periodic rays only. Demanding continuity of the Casimir energy under small deformations of the manifold, the method is extended to integrable systems. The Casimir energy of a massless scalar field on a manifold with boundaries includes contributions due to periodic rays that lie entirely within the boundaries. These contributions in general depend on the boundary conditions. Although the Casimir energy due to a massless scalar field may be sensitive to the physical dimensions of manifolds with boundary. In favorable cases its sign can, contrary to conventional wisdom, be inferred without calculation of the Casimir energy
The Casimir effect for pistons with transmittal boundary conditions
Fucci, Guglielmo
2017-11-01
This work focuses on the analysis of the Casimir effect for pistons subject to transmittal boundary conditions. In particular we consider, as piston configuration, a direct product manifold of the type I × N where I is a closed interval of the real line and N is a smooth compact Riemannian manifold. By utilizing the spectral zeta function regularization technique, we compute the Casimir energy of the system and the Casimir force acting on the piston. Explicit results for the force are provided when the manifold N is a d-dimensional sphere.
Repulsive Casimir and Casimir–Polder forces
International Nuclear Information System (INIS)
Milton, Kimball A; Abalo, E K; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen Å
2012-01-01
Casimir and Casimir–Polder repulsions have been known for more than 50 years. The general ‘Lifshitz’ configuration of parallel semi-infinite dielectric slabs permits repulsion if they are separated by a dielectric fluid that has a value of permittivity that is intermediate between those of the dielectric slabs. This was indirectly confirmed in the 1970s, and more directly by Capasso’s group recently. It has also been known for many years that electrically and magnetically polarizable bodies can experience a repulsive quantum vacuum force. More amenable to practical application are situations where repulsion could be achieved between ordinary conducting and dielectric bodies in vacuum. The status of the field of Casimir repulsion with emphasis on some recent developments will be surveyed. Here, stress will be placed on analytic developments, especially on Casimir–Polder (CP) interactions between anisotropically polarizable atoms, and CP interactions between anisotropic atoms and bodies that also exhibit anisotropy, either because of anisotropic constituents, or because of geometry. Repulsion occurs for wedge-shaped and cylindrical conductors, provided the geometry is sufficiently asymmetric, that is, either the wedge is sufficiently sharp or the atom is sufficiently far from the cylinder. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker’s 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (review)
Casimir amplitudes in topological quantum phase transitions.
Griffith, M A; Continentino, M A
2018-01-01
Topological phase transitions constitute a new class of quantum critical phenomena. They cannot be described within the usual framework of the Landau theory since, in general, the different phases cannot be distinguished by an order parameter, neither can they be related to different symmetries. In most cases, however, one can identify a diverging length at these topological transitions. This allows us to describe them using a scaling approach and to introduce a set of critical exponents that characterize their universality class. Here we consider some relevant models of quantum topological transitions associated with well-defined critical exponents that are related by a quantum hyperscaling relation. We extend to these models a finite-size scaling approach based on techniques for calculating the Casimir force in electromagnetism. This procedure allows us to obtain universal Casimir amplitudes at their quantum critical points. Our results verify the validity of finite-size scaling in these systems and confirm the values of the critical exponents obtained previously.
Casimir amplitudes in topological quantum phase transitions
Griffith, M. A.; Continentino, M. A.
2018-01-01
Topological phase transitions constitute a new class of quantum critical phenomena. They cannot be described within the usual framework of the Landau theory since, in general, the different phases cannot be distinguished by an order parameter, neither can they be related to different symmetries. In most cases, however, one can identify a diverging length at these topological transitions. This allows us to describe them using a scaling approach and to introduce a set of critical exponents that characterize their universality class. Here we consider some relevant models of quantum topological transitions associated with well-defined critical exponents that are related by a quantum hyperscaling relation. We extend to these models a finite-size scaling approach based on techniques for calculating the Casimir force in electromagnetism. This procedure allows us to obtain universal Casimir amplitudes at their quantum critical points. Our results verify the validity of finite-size scaling in these systems and confirm the values of the critical exponents obtained previously.
An ``Anatomic approach" to study the Casimir effect
Intravaia, Francesco; Haakh, Harald; Henkel, Carsten
2010-03-01
The Casimir effect, in its simplest definition, is a quantum mechanical force between two objects placed in vacuum. In recent years the Casimir force has been the object of an exponentially growing attention both from theorists and experimentalists. A new generation of experiments paved the way for new challenges and spotted some shadows in the comparison to theory. Here we are going to isolate different contributions to the Casimir interaction and perform a detailed study to shine new light on this phenomenon. As an example, the contributions of Foucault (eddy current) modes will be discussed in different configurations. This ``anatomic approach'' allows to clearly put into evidence special features and to explain unusual behaviors. This brings new physical understanding on the undergoing physical mechanisms and suggests new ways to engineer the Casimir effect.
Casimir effect in presence of spontaneous Lorentz symmetry breaking
Escobar, C. A.
2018-01-01
The Casimir effect is one of the most remarkable consequences of the nonzero vacuum energy predicted by quantum field theory. In this contribution we study the Lorentz-violation effects of the minimal standard-model extension on the Casimir force between two parallel conducting plates in the vacuum. Using a perturbative method, we compute the relevant Green’s function which satisfies given boundary conditions. The standard point-splitting technique allow us to express the vacuum expectation value of the stress-energy tensor in terms of this Green’s function. Finally, we study the Casimir energy and the Casimir force paying particular attention to the quantum effects as approaching the plates.
Casimir stress in materials: Hard divergency at soft walls
Griniasty, Itay; Leonhardt, Ulf
2017-11-01
The Casimir force between macroscopic bodies is well understood, but not the Casimir stress inside bodies. Suppose empty space or a uniform medium meets a soft wall where the refractive index is continuous but its derivative jumps. For this situation we predict a characteristic power law for the stress inside the soft wall and close to its edges. Our result shows that such edges are not tolerated in the aggregation of liquids at surfaces, regardless whether the liquid is attracted or repelled.
Casimir energy and the possibility of higher dimensional manipulation
Obousy, R. K.; Saharian, A. A.
2009-01-01
It is well known that the Casimir effect is an excellent candidate for the stabilization of the extra dimensions. It has also been suggested that the Casimir effect in higher dimensions may be the underlying phenomenon that is responsible for the dark energy which is currently driving the accelerated expansion of the universe. In this paper we suggest that, in principle, it may be possible to directly manipulate the size of an extra dimension locally using Standard Model fields in the next ge...
Casimir Energies for Isorefractive or Diaphanous Balls
Directory of Open Access Journals (Sweden)
Kimball A. Milton
2018-03-01
Full Text Available It is known that the Casimir self-energy of a homogeneous dielectric ball is divergent, although a finite self-energy can be extracted through second order in the deviation of the permittivity from the vacuum value. The exception occurs when the speed of light inside the spherical boundary is the same as that outside, so the self-energy of a perfectly conducting spherical shell is finite, as is the energy of a dielectric-diamagnetic sphere with ε μ = 1 , a so-called isorefractive or diaphanous ball. Here we re-examine that example and attempt to extend it to an electromagnetic δ -function sphere, where the electric and magnetic couplings are equal and opposite. Unfortunately, although the energy expression is superficially ultraviolet finite, additional divergences appear that render it difficult to extract a meaningful result in general, but some limited results are presented.
Casimir scaling, glueballs, and hybrid gluelumps
International Nuclear Information System (INIS)
Mathieu, V.; Semay, C.; Brau, F.
2006-01-01
Assuming that the Casimir scaling hypothesis is well verified in QCD, masses of glueballs and hybrid gluelumps (gluon attached to a point-like c anti c pair) are computed within the framework of the rotating string formalism. In our model, two gluons are attached by an adjoint string in a glueball, while the gluon and the colour octet c anti c pair are attached by two fundamental strings in a hybrid gluelump. Masses for such exotic hadrons are computed with very few free parameters. These predictions can serve as a guide for experimental searches. In particular, the ground-state glueballs lie on a Regge trajectory and the lightest 2 ++ state has a mass compatible with some experimental candidates. (orig.)
Zeta Function Regularization in Casimir Effect Calculations and J. S. Dowker's Contribution
Elizalde, Emilio
2012-07-01
A summary of relevant contributions, ordered in time, to the subject of operator zeta functions and their application to physical issues is provided. The description ends with the seminal contributions of Stephen Hawking and Stuart Dowker and collaborators, considered by many authors as the actual starting point of the introduction of zeta function regularization methods in theoretical physics, in particular, for quantum vacuum fluctuation and Casimir effect calculations. After recalling a number of the strengths of this powerful and elegant method, some of its limitations are discussed. Finally, recent results of the so called operator regularization procedure are presented.
Repulsive Casimir force from fractional Neumann boundary conditions
International Nuclear Information System (INIS)
Lim, S.C.; Teo, L.P.
2009-01-01
This Letter studies the finite temperature Casimir force acting on a rectangular piston associated with a massless fractional Klein-Gordon field at finite temperature. Dirichlet boundary conditions are imposed on the walls of a d-dimensional rectangular cavity, and a fractional Neumann condition is imposed on the piston that moves freely inside the cavity. The fractional Neumann condition gives an interpolation between the Dirichlet and Neumann conditions, where the Casimir force is known to be always attractive and always repulsive respectively. For the fractional Neumann boundary condition, the attractive or repulsive nature of the Casimir force is governed by the fractional order which takes values from zero (Dirichlet) to one (Neumann). When the fractional order is larger than 1/2, the Casimir force is always repulsive. For some fractional orders that are less than but close to 1/2, it is shown that the Casimir force can be either attractive or repulsive depending on the aspect ratio of the cavity and the temperature.
Casimir Effect and Black Hole Radiation
Rahbardehghan, S.
2018-03-01
The gravitational field of a black hole intrinsically creates a potential barrier consisted of two reflecting boundaries; the first one far from the hole and the second one in the vicinity of its horizon. With respect to this fact and assuming the boundaries as good conductors (in view of an observer near the horizon just outside the second boundary), in a series of papers, R.M. Nugayev by considering a conformally coupled massless scalar field and based on the calculations of Candelas and Deutsch (the accelerated-mirror results) has claimed that " ...the existence of the potential barrier is as crucial for Hawking evaporation as the existence of the horizon". In this paper, by taking the same assumptions, through straightforward reasonings, we explicitly show that contrary to this claim, the effects of the first boundary on the black hole radiation are quite negligible. Moreover, the inclusion of the second boundary makes the situation more complicated, because the induced Casimir energy-momentum tensor by this boundary in its vicinity is divergent of order δ ^{-4} ( δ is the distance to the boundary).
Switching Colloidal Superstructures by Critical Casimir Forces.
Nguyen, Truc A; Newton, Arthur; Veen, Sandra J; Kraft, Daniela J; Bolhuis, Peter G; Schall, Peter
2017-09-01
Recent breakthroughs in colloidal synthesis promise the bottom-up assembly of superstructures on nano- and micrometer length scales, offering molecular analogues on the colloidal scale. However, a structural control similar to that in supramolecular chemistry remains very challenging. Here, colloidal superstructures are built and controlled using critical Casimir forces on patchy colloidal particles. These solvent-mediated forces offer direct analogues of molecular bonds, allowing patch-to-patch binding with exquisite temperature control of bond strength and stiffness. Particles with two patches are shown to form linear chains undergoing morphological changes with temperature, resembling a polymer collapse under poor-solvent conditions. This reversible temperature switching carries over to particles with higher valency, exhibiting a variety of patch-to-patch bonded structures. Using Monte Carlo simulations, it is shown that the collapse results from the growing interaction range favoring close-packed configurations. These results offer new opportunities for the active control of complex structures at the nano and micrometer scale, paving the way to novel temperature-switchable materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Evanescent radiation, quantum mechanics and the Casimir effect
Schatten, Kenneth H.
1989-01-01
An attempt to bridge the gap between classical and quantum mechanics and to explain the Casimir effect is presented. The general nature of chaotic motion is discussed from two points of view: the first uses catastrophe theory and strange attractors to describe the deterministic view of this motion; the underlying framework for chaos in these classical dynamic systems is their extreme sensitivity to initial conditions. The second interpretation refers to randomness associated with probabilistic dynamics, as for Brownian motion. The present approach to understanding evanescent radiation and its relation to the Casimir effect corresponds to the first interpretation, whereas stochastic electrodynamics corresponds to the second viewpoint. The nonlinear behavior of the electromagnetic field is also studied. This well-understood behavior is utilized to examine the motions of two orbiting charges and shows a closeness between the classical behavior and the quantum uncertainty principle. The evanescent radiation is used to help explain the Casimir effect.
Some new results of the Casimir force for rectangular cavity
International Nuclear Information System (INIS)
Zhai, X.-H.; Li, X.-Z.
2001-01-01
The Casimir effect giving rise to an attractive or repulsive force between the configuration boundaries that confine the massless scalar field is analytically approached for a p-dimensional rectangular cavity with the Dirichlet boundary conditions and different spacetime dimensions D. The Casimir force is attractive in the cases: i) p-odd hypercube when D is less than the critical dimension D c and p ≤ 29; ii) o =2 and the length ratio is less than a critical value; iii) p = 1. The Casimir force is repulsive in the cases: i) p = 2 and the length ratio is larger than a critical value; ii) the length of q edges is equal and others are much longer than q edges, in the direction of (p-q) edges; iii) (p-q) edges are much longer than q edges, in the direction of (p-q) edges
The Casimir force for 2d sinusoidal gratings
Directory of Open Access Journals (Sweden)
Marachevsky Valery N.
2016-01-01
Full Text Available The Casimir free energy for 2d gratings separated by a vacuum slit is expressed in terms of Rayleigh coefficients, a novel general approach valid for arbitrary 2d surface profiles of gratings is outlined. The normal Casimir force in the system of two identical Si gratings with 2d sinusoidal surface profiles separated by a vacuum slit is computed for several amplitudes of surface profiles, distance dependence of the force is studied. A comparison with results for flat boundaries is performed.
Casimir densities for parallel plate in the domain wall background
International Nuclear Information System (INIS)
Setare, M R
2003-01-01
The Casimir forces on two parallel plates in the conformally flat domain wall background due to a conformally coupled massless scalar field satisfying mixed boundary conditions on the plates are investigated. In the general case of mixed boundary conditions, formulae are derived for the vacuum expectation values of the energy-momentum tensor and vacuum forces acting on the boundaries
Casimir-Lifshitz force out of thermal equilibrium
Antezza, M.; Pitaevskii, L.P.; Stringari, S.; Svetovoy, Vitaly
We study the Casimir-Lifshitz interaction out of thermal equilibrium, when the interacting objects are at different temperatures. The analysis is focused on the surface-surface, surface-rarefied body, and surface-atom configurations. A systematic investigation of the contributions to the force
Interplay between geometry and temperature in the Casimir effect
Energy Technology Data Exchange (ETDEWEB)
Weber, Alexej
2010-06-23
In this thesis, we investigate the interplay between geometry and temperature in the Casimir effect for the inclined-plates, sphere-plate and cylinder-plate configurations. We use the worldline approach, which combines the string-inspired quantum field theoretical formalism with Monte Carlo techniques. The approach allows the precise computation of Casimir energies in arbitrary geometries. We analyze the dependence of the Casimir energy, force and torque on the separation parameter and temperature T, and find Casimir phenomena which are dominated by long-range fluctuations. We demonstrate that for open geometries, thermal energy densities are typically distributed on scales of thermal wavelengths. As an important consequence, approximation methods for thermal corrections based on local energy-density estimates, such as the proximity-force approximation, are found to become unreliable even at small surface-separations. Whereas the hightemperature behavior is always found to be linear in T, richer power-law behaviors at small temperatures emerge. In particular, thermal forces can develop a non-monotonic behavior. Many novel numerical as well as analytical results are presented. (orig.)
What is the temperature dependence of the Casimir effect?
Energy Technology Data Exchange (ETDEWEB)
Hoeye, J S [Department of Physics, Norwegian University of Science and Technology, N-7491, Trondheim (Norway); Brevik, I [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491, Trondheim (Norway); Aarseth, J B [Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491, Trondheim (Norway); Milton, K A [Department of Physics, Washington University, St. Louis, MO 63130 (United States)
2006-05-19
There has been recent criticism of our approach to the Casimir force between real metallic surfaces at finite temperature, saying it is in conflict with the third law of thermodynamics and in contradiction with experiment. We show that these claims are unwarranted, and that our approach has strong theoretical support, while the experimental situation is still unclear.
Switching Casimir forces with phase-change materials
Torricelli, G.; van Zwol, P. J.; Shpak, O.; Binns, C.; Palasantzas, G.; Kooi, B. J.; Svetovoy, V. B.; Wuttig, M.
2010-01-01
We demonstrate here a controllable variation in the Casimir force. Changes in the force of up to 20% at separations of similar to 100 nm between Au and Ag-In-Sb-Te (AIST) surfaces were achieved on crystallization of an amorphous sample of AIST. This material is well known for its structural
Cosmology in nonlinear multidimensional gravity and the Casimir effect
International Nuclear Information System (INIS)
Bolokhov, S V; Bronnikov, K A
2017-01-01
We study the possible cosmological models in Kaluza-Klein-type multidimensional gravity with a curvature-nonlinear Lagrangian and a spherical extra space, taking into account the Casimir energy. First, we find a minimum of the effective potential of extra dimensions, leading to a physically reasonable value of the effective cosmological constant in our 4D space-time. In this model, the huge Casimir energy density is compensated by a fine-tuned contribution of the curvature-nonlinear terms in the original action. Second, we present a viable model with slowly evolving extra dimensions and power-law inflation in our space-time. In both models, the results formulated in Einstein and Jordan frames are compared. (paper)
Non-equilibrium Casimir force between vibrating plates.
Directory of Open Access Journals (Sweden)
Andreas Hanke
Full Text Available We study the fluctuation-induced, time-dependent force between two plates confining a correlated fluid which is driven out of equilibrium mechanically by harmonic vibrations of one of the plates. For a purely relaxational dynamics of the fluid we calculate the fluctuation-induced force generated by the vibrating plate on the plate at rest. The time-dependence of this force is characterized by a positive lag time with respect to the driving. We obtain two distinctive contributions to the force, one generated by diffusion of stress in the fluid and another related to resonant dissipation in the cavity. The relation to the dynamic Casimir effect of the electromagnetic field and possible experiments to measure the time-dependent Casimir force are discussed.
Attractive electromagnetic Casimir stress on a spherical dielectric shell
International Nuclear Information System (INIS)
Graham, N.; Quandt, M.; Weigel, H.
2013-01-01
Based on calculations involving an idealized boundary condition, it has long been assumed that the stress on a spherical conducting shell is repulsive. We use the more realistic case of a Drude dielectric to show that the stress is attractive, matching the generic behavior of Casimir forces in electromagnetism. We trace the discrepancy between these two cases to interactions between the electromagnetic quantum fluctuations and the dielectric material
Casimir force between two Aharonov-Bohm selenoids
International Nuclear Information System (INIS)
Duru, I.H.
1989-06-01
We show that a force of Casimir type case be associated with the Aharonov-Bohm effect. We consider two parallel, infinitely long and thin selenoids confining the quantized fluxes n 1 and n 2 within them. Using the Green function method, the vacuum expectation value of the system's energy which includes ''self interaction'' terms and a finite ''mutual interaction'' term is calculated. 8 refs
On the static Casimir effect with parity-breaking mirrors
Energy Technology Data Exchange (ETDEWEB)
Fosco, C.D. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche and Instituto Balseiro, Bariloche (Argentina); Remaggi, M.L. [Universidad Nacional de Cuyo, Facultad de Ciencias Exactas y Naturales, Mendoza (Argentina)
2017-03-15
We study the Casimir interaction energy due to the vacuum fluctuations of the electromagnetic (EM) field in the presence of two mirrors, described by 2+1-dimensional, generally nonlocal actions, which may contain both parity-conserving and parity-breaking terms. We compare the results with the ones corresponding to Chern-Simons boundary conditions and evaluate the interaction energy for several particular situations. (orig.)
Tuning the Mass of Chameleon Fields in Casimir Force Experiments
Brax, Ph; Davis, A C; Shaw, D J; Iannuzzi, D
2010-01-01
We have calculated the chameleon pressure between two parallel plates in the presence of an intervening medium that affects the mass of the chameleon field. As intuitively expected, the gas in the gap weakens the chameleon interaction mechanism with a screening effect that increases with the plate separation and with the density of the intervening medium. This phenomenon might open up new directions in the search of chameleon particles with future long range Casimir force experiments.
On the global Casimir effect in the Schwarzschild spacetime
Muniz, C. R.; Tahim, M. O.; Cunha, M. S.; Vieira, H. S.
2018-01-01
In this paper we study the vacuum quantum fluctuations of the stationary modes of an uncharged scalar field with mass m around a Schwarzschild black hole with mass M, at zero and non-zero temperatures. The procedure consists of calculating the energy eigenvalues starting from the exact solutions found for the dynamics of the scalar field, considering a frequency cutoff in which the particle is not absorbed by the black hole. From this result, we obtain the exterior contributions for the vacuum energy associated to the stationary states of the scalar field, by considering the half-summing of the levels of energy and taking into account the respective degeneracies, in order to better capture the nontrivial topology of the black hole spacetime. Then we use the Riemann's zeta function to regularize the vacuum energy thus found. Such a regularized quantity is the Casimir energy, whose analytic computation we show to yield a convergent series. The Casimir energy obtained does not take into account any boundaries artificially imposed on the system, just the nontrivial spacetime topology associated to the source and its singularity. We suggest that this latter manifests itself through the vacuum tension calculated on the event horizon. We also investigate the problem by considering the thermal corrections via Helmholtz free energy calculation, computing the Casimir internal energy, the corresponding tension on the event horizon, the Casimir entropy, and the thermal capacity of the regularized quantum vacuum, analyzing their behavior at low and high temperatures, pointing out the thermodynamic instability of the system in the considered regime, i.e. mMll 1.
Energy Technology Data Exchange (ETDEWEB)
Ellingsen, Simen Andreas Aadnoey
2011-01-15
The present thesis focuses on several topics within three separate but related branches of the overall field of dispersion forces. The three branches are: temperature corrections to the Casimir force between real materials (Part 1), explicit calculation of Casimir energy in wedge geometries (Part 2), and Casimir-Polder forces on particles out of thermal equilibrium (Part 3). Part 1 deals primarily with analysis of a previously purported thermodynamic inconsistency in the Casimir-Lifshitz free energy of the interaction of two plane mirrors - violation of the third law of thermodynamics - when the latter's dielectric response is described with dissipative models. It is shown analytically and numerically that the Casimir entropy of the interaction between two metallic mirrors described by the Drude model does tend to zero at zero temperature, provided electronic relaxation does not vanish. The leading order terms at low temperature are found. A similar calculation is carried out for the interaction of semiconductors with small but non-zero DC conductivity. In a generalisation, it is shown that a violation of the third law can only occur for permittivities whose low-frequency behaviour is temperature dependent near zero temperature. A calculation using path integral methods shows that the low temperature behaviour of the interaction of fluctuating Foucault currents in two mirrors of Drude metal is identical to that of the full Casimir-Lifshitz free energy, reasserting a previous finding by Intravaia and Henkel that such fluctuating bulk currents are the physical reason for the anomalous entropy behaviour. In a related effort, an analysis of the frequency dependence of the Casimir force by Ford is generalised to imperfectly reflecting mirrors. A paradox is pointed out, in that the effects of a perturbation of the reflecting properties of the mirrors in a finite frequency window can be calculated in two ways giving different results. It is concluded that optimistic
On convergence generation in computing the electro-magnetic Casimir force
International Nuclear Information System (INIS)
Schuller, F.
2008-01-01
We tackle the very fundamental problem of zero-point energy divergence in the context of the Casimir effect. We calculate the Casimir force due to field fluctuations by using standard cavity radiation modes. The validity of convergence generation by means of an exponential energy cut-off factor is discussed in detail. (orig.)
A verification of quantum field theory – measurement of Casimir force
Indian Academy of Sciences (India)
Abstract. Here we review our work on measurement of the Casimir force between a large alu- minum coated a sphere and flat plate using an atomic force microscope. The average statistical pre- cision is 1% of the force measured at the closest separation. We have also shown nontrival boundary dependence of the Casimir ...
Towards measurement of the Casimir force between parallel plates separated at sub-mircon distance
Syed Nawazuddin, M.B.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Berenschot, Johan W.; de Boer, Meint J.; Elwenspoek, Michael Curt
2011-01-01
Ever since its prediction, experimental investigation of the Casimir force has been of great scientific interest. Many research groups have successfully attempted quantifying the force with different device geometries; however measurement of the Casimir force between parallel plates with sub-micron
Hide it to see it better: a robust setup to probe the thermal Casimir effect.
Bimonte, Giuseppe
2014-06-20
We describe a Casimir setup consisting of two aligned sinusoidally corrugated Ni surfaces, one of which is "hidden" by a thin opaque layer of gold with a flat exposed surface. The gold layer acts as a low-pass filter that allows for a clean observation of the controversial thermal Casimir force between the corrugations, with currently available Casimir apparatuses. The proposed scheme of measurement, based on the phase-dependent modulation of the Casimir force, requires no electrostatic calibrations of the apparatus, and is unaffected by uncertainties in the knowledge of the optical properties of the surfaces. This scheme should allow for an unambiguous discrimination between alternative theoretical prescriptions that have been proposed in the literature for the thermal Casimir effect.
Casimir effect for parallel plates in a Friedmann-Robertson-Walker universe
Bezerra de Mello, E. R.; Saharian, A. A.; Setare, M. R.
2017-03-01
We evaluate the Hadamard function, the vacuum expectation values (VEVs) of the field squared and the energy-momentum tensor for a massive scalar field with a general curvature coupling parameter in the geometry of two parallel plates on a spatially flat Friedmann-Robertson-Walker background with a general scale factor. On the plates, the field operator obeys the Robin boundary conditions with the coefficients depending on the scale factor. In all the spatial regions, the VEVs are decomposed into the boundary-free and boundary-induced contributions. Unlike the problem with the Minkowski bulk, in the region between the plates, the normal stress is not homogeneous and does not vanish in the geometry of a single plate. Near the plates, it has different signs for accelerated and decelerated expansions of the Universe. The VEV of the energy-momentum tensor, in addition to the diagonal components, has a nonzero off-diagonal component describing an energy flux along the direction normal to the boundaries. Expressions are derived for the Casimir forces acting on the plates. Depending on the Robin coefficients and on the vacuum state, these forces can be either attractive or repulsive. An important difference from the corresponding result in the Minkowski bulk is that the forces on the separate plates, in general, are different if the corresponding Robin coefficients differ. We give the applications of general results for the class of α vacua in the de Sitter bulk. It is shown that, compared with the Bunch-Davies vacuum state, the Casimir forces for a given α vacuum may change the sign.
Casimir energy of massless fermions in the Slab-bag
International Nuclear Information System (INIS)
Paola, R.D.M. de; Rodrigues, R.B.; Svaiter, N.F.
1999-04-01
The zero-point energy of a massless fermion field in the interior of two parallel plates in a D-dimensional space-time at zero temperature is calculated. In order to regularize the model, a mix between dimensional and zeta function regularization procedure is used and it is founded that the regularized zero-point energy density is finite for any number of space-time dimensions. We present a general expression for the Casimir energy for the fermionic field in such a situation. (author)
Casimir entropy for a ball in front of a plane
Bordag, M.; Pirozhenko, I. G.
2010-12-01
The violation of the third law of thermodynamics for metals described by the Drude model and for dielectrics with finite dc conductivity is one of the most interesting problems in the field of the Casimir effect. It manifests itself as a nonvanishing of the entropy for vanishing temperature. We review the relevant calculations for plane surfaces and calculate the corresponding contributions for a ball in front of a plane. In this geometry, these appear in much the same way as for parallel planes. We conclude that the violation of the 3rd law is not related to the infinite size of the planes.
Attractive Casimir effect in an infrared modified gluon bag model
International Nuclear Information System (INIS)
Oxman, L.E.; Amaral, R.L.P.G.; Svaiter, N.F.
2005-01-01
In this work, we are motivated by previous attempts to derive the vacuum contribution to the bag energy in terms of familiar Casimir energy calculations for spherical geometries. A simple infrared modified model is introduced which allows studying the effects of the analytic structure as well as the geometry in a clear manner. In this context, we show that if a class of infrared vanishing effective gluon propagators is considered, then the renormalized vacuum energy for a spherical bag is attractive, as required by the bag model to adjust hadron spectroscopy
International Nuclear Information System (INIS)
Seyedzahedi, A.; Moradian, A.; Setare, M.R.
2016-01-01
We investigate the Casimir force for a system composed of two thick slabs as substrates within three different homogeneous layers. We use the scattering approach along with the Matsubara formalism in order to calculate the Casimir force at finite temperature. First, we focus on constructing the reflection matrices and then we calculate the Casimir force for a water–lipid system. According to the conventional use of silicon as a substrate, we apply the formalism to calculate the Casimir force for layers of Au, VO 2 , mica, KCl and foam rubber on the thick slabs of silicon. Afterwards, introducing an increasing factor, we compare our results with Lifshitz force in the vacuum between two semispaces of silicon in order to illustrate the influence of the layers on intensifying the Casimir force. We also calculate the Casimir force between two slabs of the forementioned materials with finite thicknesses to indicate the substrate's role in increasing the obtained Casimir force. Our simple calculation is interesting since one can extend it along with the Rigorous Coupled Wave Analysis to systems containing inhomogeneous layers as good candidates for designing nanomechanical devices.
Energy Technology Data Exchange (ETDEWEB)
Seyedzahedi, A. [Department of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Moradian, A., E-mail: a.moradian@uok.ac.ir [Department of Science, Campus of Bijar, University of Kurdistan, Bijar (Iran, Islamic Republic of); Setare, M.R., E-mail: rezakord@ipm.ir [Department of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)
2016-04-01
We investigate the Casimir force for a system composed of two thick slabs as substrates within three different homogeneous layers. We use the scattering approach along with the Matsubara formalism in order to calculate the Casimir force at finite temperature. First, we focus on constructing the reflection matrices and then we calculate the Casimir force for a water–lipid system. According to the conventional use of silicon as a substrate, we apply the formalism to calculate the Casimir force for layers of Au, VO{sub 2}, mica, KCl and foam rubber on the thick slabs of silicon. Afterwards, introducing an increasing factor, we compare our results with Lifshitz force in the vacuum between two semispaces of silicon in order to illustrate the influence of the layers on intensifying the Casimir force. We also calculate the Casimir force between two slabs of the forementioned materials with finite thicknesses to indicate the substrate's role in increasing the obtained Casimir force. Our simple calculation is interesting since one can extend it along with the Rigorous Coupled Wave Analysis to systems containing inhomogeneous layers as good candidates for designing nanomechanical devices.
Modulation of the Casimir force by laser pulses: Influence of oxide films on the silicon surface
Klimchitskaya, G. L.; Bukina, M. N.; Churkin, Yu. V.; Yurova, V. A.
2010-10-01
The possibility of modulating the Casimir force that acts in an air medium between a gold sphere and a silicon plate irradiated by laser pulses has been studied. It has been demonstrated that the oxide film that is formed on the silicon surface in air hardly affects the possibility of modulating the Casimir force when the distances between interacting bodies are of the order of 100 nm. With an increase in the distance, the modulation depth decreases; however, this region is of less practical interest, because the Casimir forces become too weak.
Casimir force for a scalar field in warped brane worlds
International Nuclear Information System (INIS)
Linares, Roman; Morales-Tecotl, Hugo A.; Pedraza, Omar
2008-01-01
In looking for imprints of extra dimensions in braneworld models one usually builds these so that they are compatible with known low energy physics and thus focuses on high energy effects. Nevertheless, just as submillimeter Newton's law tests probe the mode structure of gravity other low energy tests might apply to matter. As a model example, in this work we determine the 4D Casimir force corresponding to a scalar field subject to Dirichlet boundary conditions on two parallel planes lying within the single brane of a Randall-Sundrum scenario extended by one compact extra dimension. Using the Green's function method such a force picks the contribution of each field mode as if it acted individually but with a weight given by the square of the mode wave functions on the brane. In the low energy regime one regains the standard 4D Casimir force that is associated to a zero mode in the massless case or to a quasilocalized or resonant mode in the massive one while the effect of the extra dimensions gets encoded as an additional term.
Rectification of a Casimir Nanomachine with a Triangular Wave Signal
Directory of Open Access Journals (Sweden)
ali moradian
2017-11-01
Full Text Available In this paper, we investigate the Casimir nano system composed of two quadrisected dielectric disks separated by a thin gap. Initially the two disks have the same surface dielectric distributions. We use scatting approach in the weak coupling limit and show that the top plate experiences a torque if it rotates about its axes by an angle. Consequently, we will be able to calculate. Quite interesting, such a nanomachine may be used to examine the dielectric dependence of the Casimir torque. Our small system can be used to measure small torques. We assume that the top disk is mounted on an axle and part of the rotational friction in the system comes from the axial friction and an external load is mounted on it. For such a system with specified parameters, we can estimate inertia and axial friction. Therefor we can neglect the inertia term and use the over damped regime to describe the dynamics of our system. We show that our small system can rectify a periodic square-wave angular velocity and we obtain the average angular velocity of the top plate.
Energy Technology Data Exchange (ETDEWEB)
Mohideen, Umar [Univ. of California, Riverside, CA (United States)
2015-04-14
Duration of award was from 4/15/10-4/14/15. In this grant period our contributions to the field of VdW/Casimir forces are 24 refereed publications in journals such as Physical Review Letters (4) [1-4], Physical Review B (10) [5-14], Physical Review D (2) [15,16], Applied Physics Letters (1) [17], Review of Scientific Instruments (1) [18] and the International Journal of Modern Physics A (5) [19-23] and B(1) (invited review article [24]). We presented 2 plenary conference talks, 3 lectures at the Pan American School on Frontiers in Casimir Physics, 2 conferences, 1 colloquium and 11 APS talks. If publications are restricted to only those with direct connection to the aims proposed in the prior grant period, then it will be a total of 12: Physical Review Letters (3) [2-4], Physical Review B (6) [6-8,12,13,25], Review of Scientific Instruments (1) [18], International Journal of Modern Physics A (1) [19] and B(1) [169]. A brief aggregated description of the directly connected accomplishments is below. The following topics are detailed: dispersion force measurements with graphene, dispersion force from ferromagnetic metals, conclusion on role of electrostatic patches, UV radiation induced modification of the Casimir force, low temperature measurement of the Casimir force, and Casimir force from thin fluctuating membranes.
Casimir force in the Goedel space-time and its possible induced cosmological inhomogeneity
Energy Technology Data Exchange (ETDEWEB)
Khodabakhshi, Sh. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of); Shojai, A. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), Foundations of Physics Group, School of Physics, Tehran (Iran, Islamic Republic of)
2017-07-15
The Casimir force between two parallel plates in the Goedel universe is computed for a scalar field at finite temperature. It is observed that when the plates' separation is comparable with the scale given by the rotation of the space-time, the force becomes repulsive and then approaches zero. Since it has been shown previously that the universe may experience a Goedel phase for a small period of time, the induced inhomogeneities from the Casimir force are also studied. (orig.)
Speeding up the antidynamical Casimir effect with nonstationary qutrits
Dodonov, A. V.; Díaz-Guevara, J. J.; Napoli, A.; Militello, B.
2017-09-01
The antidynamical Casimir effect (ADCE) is a term coined to designate the coherent annihilation of excitations due to resonant external perturbation of system parameters, allowing for extraction of quantum work from nonvacuum states of some field. Originally proposed for a two-level atom (qubit) coupled to a single-cavity mode in the context of the nonstationary quantum Rabi model, it suffered from a very low transition rate and correspondingly narrow resonance linewidth. In this paper we show analytically and numerically that the ADCE rate can be increased by at least one order of magnitude by replacing the qubit by an artificial three-level atom (qutrit) in a properly chosen configuration. For the cavity thermal state we demonstrate that the dynamics of the average photon number and atomic excitation is completely different from the qubit's case, while the behavior of the total number of excitations is qualitatively similar yet significantly faster.
Zeta-function approach to Casimir energy with singular potentials
International Nuclear Information System (INIS)
Khusnutdinov, Nail R.
2006-01-01
In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed
Casimir effect in multidimensional quantum supergravities and supersymmetry breaking
International Nuclear Information System (INIS)
Odintsov, S.D.
1988-01-01
The one-loop effective action (the Casimir gravitational energy) of the aribitrary Einstein supergravity on the background M/sub 4/ X T/sub D-4/, where M/sub 4/ is the Minkowski space with non-zero temperature, T/sub d/ is the d-dimensional torus, is calculated. The problem of quantum breaking of supersymmetry is discussed. The Vilkovisky-De Witt effective action in the D-dimensional Einstein gravity with the Λ-term on the background M/sub 4/ X T/sub D-4/ is found. An idea is expressed that a temperature phase transition in Kaluza-Klein theories is possible. For d=5 gravity, the Vilkovisky-De Witt effective a< ction on the R/sub 4/ X S/sub 1/, where R/sub 4/ is fourdimensional curved space-time with non-zero temperature, is found
Resolution of an apparent inconsistency in the electromagnetic Casimir effect
International Nuclear Information System (INIS)
Alnes, H; Olaussen, K; Ravndal, F; Wehus, I K
2007-01-01
The vacuum expectation value of the electromagnetic energy-momentum tensor between two parallel plates in spacetime dimensions D > 4 is calculated in the axial gauge. While the pressure between the plates agrees with the global Casimir force, the energy density is divergent at the plates and not compatible with the total energy which follows from the force. However, subtracting the divergent self-energies of the plates, the resulting energy is finite and consistent with the force. In analogy with the corresponding scalar case for spacetime dimensions D > 2, the divergent self-energy of a single plate can be related to the lack of conformal invariance of the electromagnetic Lagrangian for dimensions D > 4. (fast track communication)
Energy Technology Data Exchange (ETDEWEB)
Grueneberg, Daniel
2008-02-15
To study how the behavior of the thermodynamic Casimir force changes qualitatively and quantitatively due to the presence of such interactions - compared to systems with purely short-range interactions - is the aim of this work. Considering d-dimensional models belonging to the universality class of the O(n)-symmetrical systems, the thermodynamic Casimir force and its leading corrections are derived for temperatures at and above the transition temperature (T{>=}T{sub c,{infinity}}). The underlying pair potential is assumed to be isotropic and long-ranged, decaying asymptotically proportional to x{sup -(d+{sigma}}{sup )} for large separations x, where the value of the parameter {sigma} is restricted to the interval 2<{sigma}<4. By solving an appropriate spherical model in 2
Casimir-Foucault interaction: Free energy and entropy at low temperature
International Nuclear Information System (INIS)
Intravaia, Francesco; Ellingsen, Simen A.; Henkel, Carsten
2010-01-01
It was recently found that thermodynamic anomalies which arise in the Casimir effect between metals described by the Drude model can be attributed to the interaction of fluctuating Foucault (or eddy) currents [F. Intravaia and C. Henkel, Phys. Rev. Lett. 103, 130405 (2009).] We focus on the transverse electric (TE) polarization, where the anomalies occur, and show explicitly that the two leading terms of the low-temperature correction to the Casimir free energy of interaction between two plates are identical to those pertaining to the Foucault current interaction alone, up to a correction which is very small for good metals. Moreover, a mode density along real frequencies is introduced, showing that the TE contribution to the Casimir free energy, as given by the Lifshitz theory, separates in a natural manner into contributions from eddy currents and propagating cavity modes, respectively. The latter have long been known to be of little importance to the low-temperature Casimir anomalies. This convincingly demonstrates that eddy current modes are responsible for the large temperature correction to the Casimir effect between Drude metals, predicted by the Lifshitz theory, but not observed in experiments.
Casimir-Foucault interaction: Free energy and entropy at low temperature
Intravaia, Francesco; Ellingsen, Simen Å.; Henkel, Carsten
2010-09-01
It was recently found that thermodynamic anomalies which arise in the Casimir effect between metals described by the Drude model can be attributed to the interaction of fluctuating Foucault (or eddy) currents [F. Intravaia and C. Henkel, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.130405 103, 130405 (2009).] We focus on the transverse electric (TE) polarization, where the anomalies occur, and show explicitly that the two leading terms of the low-temperature correction to the Casimir free energy of interaction between two plates are identical to those pertaining to the Foucault current interaction alone, up to a correction which is very small for good metals. Moreover, a mode density along real frequencies is introduced, showing that the TE contribution to the Casimir free energy, as given by the Lifshitz theory, separates in a natural manner into contributions from eddy currents and propagating cavity modes, respectively. The latter have long been known to be of little importance to the low-temperature Casimir anomalies. This convincingly demonstrates that eddy current modes are responsible for the large temperature correction to the Casimir effect between Drude metals, predicted by the Lifshitz theory, but not observed in experiments.
Casimir force experiments with quartz tuning forks and an atomic force microscope (AFM)
International Nuclear Information System (INIS)
Ludwig, T
2008-01-01
The aim of the measurement series is to study the Casimir force, specifically the effects of different materials and geometries. The art of measuring sub-nano Newton forces has been engineered to a great extent in the material sciences, especially for the atomic force microscope. In today's scanning microscope technologies there are several common methods used to measure sub-nano Newton forces. While the commercial atomic force microscopes (AFM) mostly work with soft silicon cantilevers, there are a large number of reports from university groups on the use of quartz tuning forks to get high resolution AFM pictures, to measure shear forces or to create new force sensors. The quartz tuning fork based force sensor has a number of advantages over the silicon cantilever, but also has some disadvantages. In this report the method based on quartz tuning forks is described with respect to their usability for Casimir force measurements and compared with other successful techniques. Furthermore, a design for Casimir force measurements that was set up in Berlin will be described and practical experimental aspects will be discussed. A status report on the Casimir experiments in Berlin will be given, including the experimental setup. In order to study the details of the Casimir effect the apparatus and active surfaces have to be improved further. The surfaces have to be flatter and cleaner. For better resolution, cantilevers and tuning forks with a low spring constant have to be employed
Banishev, Alexandr; Chang, Chia-Cheng; Mohideen, Umar
2012-02-01
The Casimir effect is important in various fields from atomic physics to nanotechnology. According to the Lifshitz theory of the Casimir force, the interaction between two objects depends both on their dielectric permittivity and magenetic permeability. Thus the role of magnetic properties on the Casimir force is interesting particularly due to the possibility of a reduction the Casimir force. In this report we will present the results of a Casimir force measurement between a magnetic material such as nickel coated on SiO2 plate and a Au-coated sphere.
Casimir effect in rugby-ball type flux compactifications
International Nuclear Information System (INIS)
Elizalde, Emilio; Minamitsuji, Masato; Naylor, Wade
2007-01-01
As a continuation of the work by Minamitsuji, Naylor, and Sasaki [J. High Energy Phys. 12 (2006) 079], we discuss the Casimir effect for a massless bulk scalar field in a 4D toy model of a 6D warped flux compactification model, to stabilize the volume modulus. The one-loop effective potential for the volume modulus has a form similar to the Coleman-Weinberg potential. The stability of the volume modulus against quantum corrections is related to an appropriate heat kernel coefficient. However, to make any physical predictions after volume stabilization, knowledge of the derivative of the zeta function, ζ ' (0) (in a conformally related spacetime) is also required. By adding up the exact mass spectrum using zeta-function regularization, we present a revised analysis of the effective potential. Finally, we discuss some physical implications, especially concerning the degree of the hierarchy between the fundamental energy scales on the branes. For a larger degree of warping our new results are very similar to the ones given by Minamitsuji, Naylor, and Sasaki [J. High Energy Phys. 12 (2006) 079] and imply a larger hierarchy. In the nonwarped (rugby ball) limit the ratio tends to converge to the same value, independently of the bulk dilaton coupling
Determination of the Contact Angle Based on the Casimir Effect
Mazuruk, Konstantin; Volz, Martin P.
2015-01-01
On a macroscopic scale, a nonreactive liquid partially covering a homogeneous solid surface will intersect the solid at an angle called the contact angle. For molten metals and semiconductors, the contact angle is materially dependent upon both the solid and liquid and typical values fall in the range 80-170 deg, depending on the crucible material. On a microscopic scale, there does not exist a precise and sharp contact angle but rather the liquid and solid surfaces merge smoothly and continuously. Consider the example of the so called detached Bridgman crystal growth process. In this technique, a small gap is formed between the growing crystal and the crucible. At the crystal/melt interface, a meniscus ring is formed. Its width can be in the range of a few micrometers, approaching a microscopic scale. It then becomes questionable to describe the shape of this meniscus by the contact angle. A more advanced treatment of the interface is needed and here we propose such a refined model. The interaction of the liquid surface with the solid can be calculated by considering two forces: a short-range repulsive force and a longer range (up to a few micrometers) Casimir or van der Waals force.
Effective field theory of thermal Casimir interactions between anisotropic particles.
Haussman, Robert C; Deserno, Markus
2014-06-01
We employ an effective field theory (EFT) approach to study thermal Casimir interactions between objects bound to a fluctuating fluid surface or interface dominated by surface tension, with a focus on the effects of particle anisotropy. The EFT prescription disentangles the constraints imposed by the particles' boundaries from the calculation of the interaction free energy by constructing an equivalent point particle description. The finite-size information is captured in a derivative expansion that encodes the particles' response to external fields. The coefficients of the expansion terms correspond to generalized tensorial polarizabilities and are found by matching the results of a linear response boundary value problem computed in both the full and effective theories. We demonstrate the versatility of the EFT approach by constructing the general effective Hamiltonian for a collection of particles of arbitrary shapes. Taking advantage of the conformal symmetry of the Hamiltonian, we discuss a straightforward conformal mapping procedure to systematically determine the polarizabilities and derive a complete description for elliptical particles. We compute the pairwise interaction energies to several orders for nonidentical ellipses as well as their leading-order triplet interactions and discuss the resulting preferred pair and multibody configurations. Furthermore, we elaborate on the complications that arise with pinned particle boundary conditions and show that the powerlike corrections expected from dimensional analysis are exponentially suppressed by the leading-order interaction energies.
A Toy Cosmology Using a Hubble-Scale Casimir Effect
Directory of Open Access Journals (Sweden)
Michael E. McCulloch
2014-02-01
Full Text Available The visible mass of the observable universe agrees with that needed for a flat cosmos, and the reason for this is not known. It is shown that this can be explained by modelling the Hubble volume as a black hole that emits Hawking radiation inwards, disallowing wavelengths that do not fit exactly into the Hubble diameter, since partial waves would allow an inference of what lies outside the horizon. This model of “horizon wave censorship” is equivalent to a Hubble-scale Casimir effect. This incomplete toy model is presented to stimulate discussion. It predicts a minimum mass and acceleration for the observable universe which are in agreement with the observed mass and acceleration, and predicts that the observable universe gains mass as it expands and was hotter in the past. It also predicts a suppression of variation on the largest cosmic scales that agrees with the low-l cosmic microwave background anomaly seen by the Planck satellite.
The Casimir interaction of a massive vector field between concentric spherical bodies
International Nuclear Information System (INIS)
Teo, L.P.
2011-01-01
The Casimir interaction energy due to the vacuum fluctuations of a massive vector field between two perfectly conducting concentric spherical bodies is computed. The TE contribution to the Casimir interaction energy is a direct generalization of the massless case but the TM contribution is much more complicated. Each TM mode is a linear combination of a transverse mode which is the generalization of a TM mode in the massless case and a longitudinal mode that does not appear in the massless case. In contrast to the case of two parallel perfectly conducting plates, there are no TM discrete modes that vanish identically in the perfectly conducting spherical bodies. Numerical simulations show that the Casimir interaction force between the two bodies is always attractive.
Garrett, Joseph L; Somers, David; Munday, Jeremy N
2015-06-03
Measurements of the Casimir force require the elimination of the electrostatic force between the surfaces. However, due to electrostatic patch potentials, the voltage required to minimize the total force may not be sufficient to completely nullify the electrostatic interaction. Thus, these surface potential variations cause an additional force, which can obscure the Casimir force signal. In this paper, we inspect the spatially varying surface potential of e-beamed, sputtered, sputtered and annealed, and template stripped gold surfaces with Heterodyne amplitude modulated Kelvin probe force microscopy (HAM-KPFM). It is demonstrated that HAM-KPFM improves the spatial resolution of surface potential measurements compared to amplitude modulated Kelvin probe force microscopy. We find that patch potentials vary depending on sample preparation, and that the calculated pressure can be similar to the pressure difference between Casimir force calculations employing the plasma and Drude models.
International Nuclear Information System (INIS)
Eab, C. H.; Lim, S. C.; Teo, L. P.
2007-01-01
This paper studies the Casimir effect due to fractional massless Klein-Gordon field confined to parallel plates. A new kind of boundary condition called fractional Neumann condition which involves vanishing fractional derivatives of the field is introduced. The fractional Neumann condition allows the interpolation of Dirichlet and Neumann conditions imposed on the two plates. There exists a transition value in the difference between the orders of the fractional Neumann conditions for which the Casimir force changes from attractive to repulsive. Low and high temperature limits of Casimir energy and pressure are obtained. For sufficiently high temperature, these quantities are dominated by terms independent of the boundary conditions. Finally, validity of the temperature inversion symmetry for various boundary conditions is discussed
Modelling critical Casimir force induced self-assembly experiments on patchy colloidal dumbbells.
Newton, Arthur C; Nguyen, T Anh; Veen, Sandra J; Kraft, Daniela J; Schall, Peter; Bolhuis, Peter G
2017-07-19
Colloidal particles suspended in a binary liquid mixture can interact via solvent mediated interactions, known as critical Casimir forces. For anisotropic colloids this interaction becomes directional, which leads to rich phase behavior. While experimental imaging and particle tracking techniques allow determination of isotropic effective potentials via Boltzmann inversion, the modeling of effective interaction in anisotropic systems is non-trivial precisely because of this directionality. Here we extract effective interaction potentials for non-spherical dumbbell particles from observed radial and angular distributions, by employing reference interaction site model (RISM) theory and direct Monte Carlo simulations. For colloidal dumbbell particles dispersed in a binary liquid mixture and interacting via induced critical Casimir forces, we determine the effective site-site potentials for a range of experimental temperatures. Using these potentials to simulate the system for strong Casimir forces, we reproduce the experimentally observed collapse, and provide a qualitative explanation for this behavior.
Casimir energy density for spherical universes in n-dimensional spacetime
International Nuclear Information System (INIS)
Oezcan, Mustafa
2006-01-01
We consider the Casimir effect for the massless conformal scalar field in an n-dimensional, closed, static universe. We calculate the renormalized vacuum energy density using the covariant point-splitting method, the mode-sum regularization and the renormalized vacuum energy with the zeta-function regularization. We observe that all odd spacetime dimensions give us the zero renormalized vacuum energy density. For even spacetime dimensions the renormalized vacuum energy density oscillates in sign. The result agrees with three regularization techniques. The Casimir energy density for spherical universes in n-dimensional spacetime is regarded as interesting both to understand the correspondence between the sign of the effect and the dimension of manifold in topology and as a key to confirming the Casimir energy for half spherical universes (manifold with boundary) in n-dimensional spacetime
Casimir free energy of dielectric films: classical limit, low-temperature behavior and control.
Klimchitskaya, G L; Mostepanenko, V M
2017-07-12
The Casimir free energy of dielectric films, both free-standing in vacuum and deposited on metallic or dielectric plates, is investigated. It is shown that the values of the free energy depend considerably on whether the calculation approach used neglects or takes into account the dc conductivity of film material. We demonstrate that there are material-dependent and universal classical limits in the former and latter cases, respectively. The analytic behavior of the Casimir free energy and entropy for a free-standing dielectric film at low temperature is found. According to our results, the Casimir entropy goes to zero when the temperature vanishes if the calculation approach with neglected dc conductivity of a film is employed. If the dc conductivity is taken into account, the Casimir entropy takes the positive value at zero temperature, depending on the parameters of a film, i.e. the Nernst heat theorem is violated. By considering the Casimir free energy of SiO 2 and Al 2 O 3 films deposited on a Au plate in the framework of two calculation approaches, we argue that physically correct values are obtained by disregarding the role of dc conductivity. A comparison with the well known results for the configuration of two parallel plates is made. Finally, we compute the Casimir free energy of SiO 2 , Al 2 O 3 and Ge films deposited on high-resistivity Si plates of different thicknesses and demonstrate that it can be positive, negative and equal to zero. The effect of illumination of a Si plate with laser light is considered. Possible applications of the obtained results to thin films used in microelectronics are discussed.
On the Casimir scaling violation in the cusp anomalous dimension at small angle
Grozin, Andrey; Henn, Johannes; Stahlhofen, Maximilian
2017-10-01
We compute the four-loop n f contribution proportional to the quartic Casimir of the QCD cusp anomalous dimension as an expansion for small cusp angle ϕ. This piece is gauge invariant, violates Casimir scaling, and first appears at four loops. It requires the evaluation of genuine non-planar four-loop Feynman integrals. We present results up to O({φ}^4) . One motivation for our calculation is to probe a recent conjecture on the all-order structure of the cusp anomalous dimension. As a byproduct we obtain the four-loop HQET wave function anomalous dimension for this color structure.
Casimir force in the Gödel space-time and its possible induced cosmological inhomogeneity
Khodabakhshi, Sh.; Shojai, A.
2017-07-01
The Casimir force between two parallel plates in the Gödel universe is computed for a scalar field at finite temperature. It is observed that when the plates' separation is comparable with the scale given by the rotation of the space-time, the force becomes repulsive and then approaches zero. Since it has been shown previously that the universe may experience a Gödel phase for a small period of time, the induced inhomogeneities from the Casimir force are also studied.
The Casimir effect in rugby-ball type flux compactifications
Minamitsuji, M.
2008-04-01
We discuss volume stabilization in a 6D braneworld model based on 6D supergravity theory. The internal space is compactified by magnetic flux and contains codimension two 3-branes (conical singularities) as its boundaries. In general the external 4D spacetime is warped and in the unwrapped limit the shape of the internal space looks like a 'rugby ball'. The size of the internal space is not fixed due to the scale invariance of the supergravity theory. We discuss the possibility of volume stabilization by the Casimir effect for a massless, minimally coupled bulk scalar field. The main obstacle in studying this case is that the brane (conical) part of the relevant heat kernel coefficient (a6) has not been formulated. Thus as a first step, we consider the 4D analog model with boundary codimension two 1-branes. The spacetime structure of the 4D model is very similar to that of the original 6D model, where now the relevant heat kernel coefficient is well known. We derive the one-loop effective potential induced by a scalar field in the bulk by employing zeta function regularization with heat kernel analysis. As a result, the volume is stabilized for most possible choices of the parameters. Especially, for a larger degree of warping, our results imply that a large hierarchy between the mass scales and a tiny amount of effective cosmological constant can be realized on the brane. In the non-warped limit the ratio tends to converge to the same value, independently of the bulk gauge coupling constant. Finally, we will analyze volume stabilization in the original model 6D by employing the same mode-sum technique.
The Casimir effect in rugby-ball type flux compactifications
International Nuclear Information System (INIS)
Minamitsuji, M
2008-01-01
We discuss volume stabilization in a 6D braneworld model based on 6D supergravity theory. The internal space is compactified by magnetic flux and contains codimension two 3-branes (conical singularities) as its boundaries. In general the external 4D spacetime is warped and in the unwrapped limit the shape of the internal space looks like a 'rugby ball'. The size of the internal space is not fixed due to the scale invariance of the supergravity theory. We discuss the possibility of volume stabilization by the Casimir effect for a massless, minimally coupled bulk scalar field. The main obstacle in studying this case is that the brane (conical) part of the relevant heat kernel coefficient (a 6 ) has not been formulated. Thus as a first step, we consider the 4D analog model with boundary codimension two 1-branes. The spacetime structure of the 4D model is very similar to that of the original 6D model, where now the relevant heat kernel coefficient is well known. We derive the one-loop effective potential induced by a scalar field in the bulk by employing zeta function regularization with heat kernel analysis. As a result, the volume is stabilized for most possible choices of the parameters. Especially, for a larger degree of warping, our results imply that a large hierarchy between the mass scales and a tiny amount of effective cosmological constant can be realized on the brane. In the non-warped limit the ratio tends to converge to the same value, independently of the bulk gauge coupling constant. Finally, we will analyze volume stabilization in the original model 6D by employing the same mode-sum technique
Energy Technology Data Exchange (ETDEWEB)
Klimchitskaya, G.L. [Central Astronomical Observatory at Pulkovo of the Russian Academy of Sciences, Saint Petersburg (Russian Federation); Peter the Great Saint Petersburg Polytechnic University, Institute of Physics, Nanotechnology and Telecommunications, Saint Petersburg (Russian Federation)
2017-05-15
The strongest constraints on the Yukawa-type corrections to Newton's gravitational law and on the coupling constants of axion-like particles to nucleons, following from recently performed experiments of Casimir physics, are presented. Specifically, the constraints obtained from measurements of the lateral and normal Casimir forces between sinusoidally corrugated surfaces, and from the isoelectronic experiment are considered, and the ranges of their greatest strength are refined. Minor modifications in the experimental setups are proposed which allow for strengthening the resultant constraints up to an order of magnitude. The comparison with some weaker constraints derived in the Casimir regime is also made. (orig.)
Uma introdução aos métodos de cálculo da energia de Casimir
Directory of Open Access Journals (Sweden)
Passos Sobrinho J.J.
2001-01-01
Full Text Available O efeito Casimir é um dos aspectos mais intrigantes da física moderna. A previsão da existência de uma força macroscópica de origem quântica entre condutores neutros e sua posterior comprovação experimental é sem dúvida um dos triunfos da teoria quântica dos campos. Complementando uma introdução conceitual publicada recentemente nesta revista, apresentamos alguns métodos de cálculo da energia de Casimir, que é a grandeza fundamental que origina o efeito Casimir.
Kinetic Roughening and Material Optical Properties Influence on Van der Waals/Casimir Forces
van Zwol, P. J.; Palasantzas, G.
Atomic force microscopy measurements and force theory calculations using the Lifshitz theory show that van der Waals/Casimir dispersive forces have a strong dependence on surface roughness and material optical properties. It is found that at separations below 100 nm the roughness effect is
Optical properties and kinetic roughening influence on dispersive casimir and van der Waals forces
Palasantzas, G.; Svetovoy, Vitaly; van Zwol, P.J.
2010-01-01
Casimir and van der Waals dispersive forces between real material surfaces can be strongly influenced by surface roughness and the frequency dependent dielectric functions of the interacting materials. The Lifshitz theory allows calculations of these forces between two flat plates if the frequency
Optical Properties and Kinetic Roughening Influence on Dispersive Casimir and van der Waals Forces
Palasantzas, G.; Svetovoy, V. B.; Van Zwol, P. J.
2010-01-01
Casimir and van der Waals dispersive forces between real material surfaces can be strongly influenced by surface roughness and the frequency dependent dielectric functions of the interacting materials. The Lifshitz theory allows calculations of these forces between two flat plates if the frequency
Guo, Hongyu; Stan, Gheorghe; Liu, Yun
2018-02-21
Nanoparticles typically have an inherent wide size distribution that may affect the performance and reliability of many nanomaterials. Because the synthesis and purification of nanoparticles with desirable sizes are crucial to the applications of nanoparticles in various fields including medicine, biology, health care, and energy, there is a great need to search for more efficient and generic methods for size-selective nanoparticle purification/separation. Here we propose and conclusively demonstrate the effectiveness of a size-selective particle purification/separation method based on the critical Casimir force. The critical Casimir force is a generic interaction between colloidal particles near the solvent critical point and has been extensively studied in the past several decades due to its importance in reversibly controlling the aggregation and stability of colloidal particles. Combining multiple experimental techniques, we found that the critical Casimir force-induced aggregation depends on relative particle sizes in a system with larger ones aggregating first and the smaller ones remaining in solution. Based on this observation, a new size-dependent nanoparticle purification/separation method is proposed and demonstrated to be very efficient in purifying commercial silica nanoparticles in the lutidine/water binary solvent. Due to the ubiquity of the critical Casimir force for many colloidal particles in binary solvents, this method might be applicable to many types of colloidal particles.
Casimir-lifshitz force out of thermal equilibrium and asymptotic nonadditivity
Antezza, Mauro; Pitaevskii, Lev P.; Stringari, Sandro; Svetovoy, Vitaly
2006-01-01
We investigate the force acting between two parallel plates held at different temperatures. The force reproduces, as limiting cases, the well-known Casimir-Lifshitz surface-surface force at thermal equilibrium and the surface-atom force out of thermal equilibrium recently derived by M. Antezza et
Tailoring optical metamaterials to tune the atom-surface Casimir-Polder interaction.
Chan, Eng Aik; Aljunid, Syed Abdullah; Adamo, Giorgio; Laliotis, Athanasios; Ducloy, Martial; Wilkowski, David
2018-02-01
Metamaterials are fascinating tools that can structure not only surface plasmons and electromagnetic waves but also electromagnetic vacuum fluctuations. The possibility of shaping the quantum vacuum is a powerful concept that ultimately allows engineering the interaction between macroscopic surfaces and quantum emitters such as atoms, molecules, or quantum dots. The long-range atom-surface interaction, known as Casimir-Polder interaction, is of fundamental importance in quantum electrodynamics but also attracts a significant interest for platforms that interface atoms with nanophotonic devices. We perform a spectroscopic selective reflection measurement of the Casimir-Polder interaction between a Cs(6P 3/2 ) atom and a nanostructured metallic planar metamaterial. We show that by engineering the near-field plasmonic resonances of the metamaterial, we can successfully tune the Casimir-Polder interaction, demonstrating both a strong enhancement and reduction with respect to its nonresonant value. We also show an enhancement of the atomic spontaneous emission rate due to its coupling with the evanescent modes of the nanostructure. Probing excited-state atoms next to nontrivial tailored surfaces is a rigorous test of quantum electrodynamics. Engineering Casimir-Polder interactions represents a significant step toward atom trapping in the extreme near field, possibly without the use of external fields.
Klimchitskaya, G. L.; Mostepanenko, V. M.
2017-06-01
We derive constraints on the coupling constants of axionlike particles to nucleons and on the Yukawa-type corrections to Newton's gravitational law from the results of recent experiment on measuring the difference of Casimir forces between a Ni-coated sphere and Au and Ni sectors of a structured disc. Over the wide range of axion masses from 2.61 meV to 0.9 eV the obtained constraints on the axion-to-nucleon coupling are up to a factor of 14.6 stronger than all previously known constraints following from experiments on measuring the Casimir interaction. The constraints on non-Newtonian gravity found here are also stronger than all that following from the Casimir- and Cavendish-type experiments over the interaction range from 30 nm to 5.4 μ m . They are up to a factor of 177 stronger than the constraints derived recently from measuring the difference of lateral forces. Our constraints confirm previous somewhat stronger limits obtained from the isoelectronic experiment, where the contribution of the Casimir force was nullified.
The energy–momentum tensor, the trace identity and the Casimir effect
Indian Academy of Sciences (India)
physics pp. 345–360. The energy–momentum tensor, the trace identity and the Casimir effect. S G KAMATH. Department of Mathematics, Indian Institute of Technology Madras, Chennai 600 036,. India. E-mail: kamath@iitm.ac.in. MS received 11 July 2005; revised 10 October 2005; accepted 18 November 2005. Abstract.
Generalized Riemann zeta-function regularization and Casimir energy for a piecewise uniform string
International Nuclear Information System (INIS)
Li Xinzhou; Shi Xin; Zhang Jianzu.
1990-12-01
The generalized zeta-function techniques will be utilized to investigate the Casimir energy for the transverse oscillations of a piecewise uniform closed string. We find that zeta-function regularization method can lead straightforwardly to a correct result. (author). 6 refs
The casimir free energy in high- and low-temperature limits
Svetovoy, Vitaly; Esquivel, R.
2006-01-01
The problem with the temperature dependence of the Casimir force is investigated. We analyse high-temperature limit analytically making calculations at real frequencies. The purpose is to answer the questionwhy there is no continuous transition between real and ideal metals and why the result does
Gross, Markus; Gambassi, Andrea; Dietrich, S
2017-08-01
The effect of imposing a constraint on a fluctuating scalar order parameter field in a system of finite volume is studied within statistical field theory. The canonical ensemble, corresponding to a fixed total integrated order parameter (e.g., the total number of particles), is obtained as a special case of the theory. A perturbative expansion is developed which allows one to systematically determine the constraint-induced finite-volume corrections to the free energy and to correlation functions. In particular, we focus on the Landau-Ginzburg model in a film geometry (i.e., in a rectangular parallelepiped with a small aspect ratio) with periodic, Dirichlet, or Neumann boundary conditions in the transverse direction and periodic boundary conditions in the remaining, lateral directions. Within the expansion in terms of ε=4-d, where d is the spatial dimension of the bulk, the finite-size contribution to the free energy of the confined system and the associated critical Casimir force are calculated to leading order in ε and are compared to the corresponding expressions for an unconstrained (grand canonical) system. The constraint restricts the fluctuations within the system and it accordingly modifies the residual finite-size free energy. The resulting critical Casimir force is shown to depend on whether it is defined by assuming a fixed transverse area or a fixed total volume. In the former case, the constraint is typically found to significantly enhance the attractive character of the force as compared to the grand canonical case. In contrast to the grand canonical Casimir force, which, for supercritical temperatures, vanishes in the limit of thick films, in the canonical case with fixed transverse area the critical Casimir force attains for thick films a negative value for all boundary conditions studied here. Typically, the dependence of the critical Casimir force both on the temperaturelike and on the fieldlike scaling variables is different in the two ensembles.
Casimir effect due to a single boundary as a manifestation of the Weyl problem
Kolomeisky, Eugene B.; Straley, Joseph P.; Langsjoen, Luke S.; Zaidi, Hussain
2010-09-01
The Casimir self-energy of a boundary is ultraviolet-divergent. In many cases, the divergences can be eliminated by methods such as zeta-function regularization or through physical arguments (ultraviolet transparency of the boundary would provide a cutoff). Using the example of a massless scalar field theory with a single Dirichlet boundary, we explore the relationship between such approaches, with the goal of better understanding of the origin of the divergences. We are guided by the insight due to Dowker and Kennedy (1978 J. Phys. A: Math. Gen. 11 895) and Deutsch and Candelas (1979 Phys. Rev. D 20 3063) that the divergences represent measurable effects that can be interpreted with the aid of the theory of the asymptotic distribution of eigenvalues of the Laplacian discussed by Weyl. In many cases, the Casimir self-energy is the sum of cutoff-dependent (Weyl) terms having a geometrical origin, and an 'intrinsic' term that is independent of the cutoff. The Weyl terms make a measurable contribution to the physical situation even when regularization methods succeed in isolating the intrinsic part. Regularization methods fail when the Weyl terms and intrinsic parts of the Casimir effect cannot be clearly separated. Specifically, we demonstrate that the Casimir self-energy of a smooth boundary in two dimensions is a sum of two Weyl terms (exhibiting quadratic and logarithmic cutoff dependence), a geometrical term that is independent of cutoff and a non-geometrical intrinsic term. As by-products, we resolve the puzzle of the divergent Casimir force on a ring and correct the sign of the coefficient of linear tension of the Dirichlet line predicted in earlier treatments.
Thermal Casimir effect in Kerr spacetime with quintessence and massive gravitons
Energy Technology Data Exchange (ETDEWEB)
Bezerra, V.B. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil); Christiansen, H.R. [Ciencia e Tecnologia do Ceara (IFCE), Departamento de Fisica, Instituto Federal de Educacao, Sobral, CE (Brazil); Cunha, M.S. [Universidade Estadual do Ceara, Grupo de Fisica Teorica (GFT), Fortaleza, CE (Brazil); Muniz, C.R.; Tahim, M.O. [Universidade Estadual do Ceara, Faculdade de Educacao, Ciencias e Letras do Sertao Central, Quixada, CE (Brazil)
2017-11-15
Starting from an analytical expression for the Helmholtz free energy we calculate the thermal corrections to the Casimir energy density and entropy within nearby ideal parallel plates in the vacuum of a massless scalar field. Our framework is the Kerr spacetime in the presence of quintessence and massive gravitons. The high and low temperature regimes are especially analyzed in order to distinguish the main contributions. For instance, in the high temperature regime, we show that the force between the plates is repulsive and grows with both the quintessence and the massive gravitons. Regarding the Casimir entropy, our results are in agreement with the Nernst heat theorem and therefore confirm the third law of thermodynamics in the present scenario. (orig.)
Edge corrections to electromagnetic Casimir energies from general-purpose Mathieu-function routines
Blose, Elizabeth Noelle; Ghimire, Biswash; Graham, Noah; Stratton-Smith, Jeremy
2015-01-01
Scattering theory methods make it possible to calculate the Casimir energy of a perfectly conducting elliptic cylinder opposite a perfectly conducting plane in terms of Mathieu functions. In the limit of zero radius, the elliptic cylinder becomes a finite-width strip, which allows for the study of edge effects. However, existing packages for computing Mathieu functions are insufficient for this calculation because none can compute Mathieu functions of both the first and second kind for complex arguments. To address this shortcoming, we have written a general-purpose Mathieu-function package, based on algorithms developed by Alhargan. We use these routines to find edge corrections to the proximity force approximation for the Casimir energy of a perfectly conducting strip opposite a perfectly conducting plane.
Stability Analysis of a Rigid Body with a Flexible Attachment Using the Energy-Casimir Method
Posbergh, T. A.; Krishnaprasad, Perinkulam S.; Marsden, Jerrold E.
1987-01-01
We consider a system consisting of a rigid body to which a linear extensible shear beam is attached. For such a system the Energy-Casimir method can be used to investigate the stability of the equilibria. In the case we consider, it can be shown that a test for (formal) stability reduces to checking the positive definiteness of two matrices which depend on the parameters of the system and the particular equilibrium about which the stability is to be ascertained.
Energy loss mechanism for suspended micro- and nanoresonators due to the Casimir force
Gusso, André
2011-01-01
A so far not considered energy loss mechanism in suspended micro- and nanoresonators due to noncontact acoustical energy loss is investigated theoretically. The mechanism consists on the conversion of the mechanical energy from the vibratory motion of the resonator into acoustic waves on large nearby structures, such as the substrate, due to the coupling between the resonator and those structures resulting from the Casimir force acting over the separation gaps. Analytical expressions for the ...
Guérout, R.; Lambrecht, A.; Milton, K. A.; Reynaud, S.
2014-10-01
We carefully reexamine the conditions of validity for the consistent derivation of the Lifshitz-Matsubara sum formula for the Casimir pressure between metallic plane mirrors. We recover the usual expression for the lossy Drude model but not for the lossless plasma model. We give an interpretation of this new result in terms of the modes associated with the Foucault currents, which play a role in the limit of vanishing losses, in contrast to common expectations.
Out-of-equilibrium relaxation of the thermal Casimir effect in a model polarizable material.
Dean, David S; Démery, Vincent; Parsegian, V Adrian; Podgornik, Rudolf
2012-03-01
Relaxation of the thermal Casimir or van der Waals force (the high temperature limit of the Casimir force) for a model dielectric medium is investigated. We start with a model of interacting polarization fields with a dynamics that leads to a frequency dependent dielectric constant of the Debye form. In the static limit, the usual zero frequency Matsubara mode component of the Casimir force is recovered. We then consider the out-of-equilibrium relaxation of the van der Waals force to its equilibrium value when two initially uncorrelated dielectric bodies are brought into sudden proximity. For the interaction between dielectric slabs, it is found that the spatial dependence of the out-of-equilibrium force is the same as the equilibrium one, but it has a time dependent amplitude, or Hamaker coefficient, which increases in time to its equilibrium value. The final relaxation of the force to its equilibrium value is exponential in systems with a single or finite number of polarization field relaxation times. However, in systems, such as those described by the Havriliak-Negami dielectric constant with a broad distribution of relaxation times, we observe a much slower power law decay to the equilibrium value.
Casimir friction and near-field radiative heat transfer in graphene structures
International Nuclear Information System (INIS)
Volokitin, A.I.; Samara State Technical Univ.
2017-01-01
The dependence of the Casimir friction force between a graphene sheet and a (amorphous) SiO 2 substrate on the drift velocity of the electrons in the graphene sheet is studied. It is shown that the Casimir friction is strongly enhanced for the drift velocity above the threshold velocity when the friction is determined by the resonant excitation of the surface phonon-polaritons in the SiO 2 substrate and the electron-hole pairs in graphene. The theory agrees well with the experimental data for the current-voltage dependence for unsuspended graphene on the SiO 2 substrate. The theories of the Casimir friction and the near-field radiative energy transfer are used to study the heat generation and dissipation in graphene due to the interaction with phonon-polaritons in the (amorphous) SiO 2 substrate and acoustic phonons in graphene. For suspended graphene, the energy transfer coefficient at nanoscale gap is ∝ three orders of magnitude larger than the radiative heat transfer coefficient of the blackbody radiation limit.
Casimir energy of a scalar field with a space-dependent mass distribution
International Nuclear Information System (INIS)
Aoyama, H.
1984-01-01
The Casimir energy is evaluated for a free scalar field that has a mass term m 2 (x 1 ), depending on one space coordinate x 1 . The formalism for evaluating the Casimir energy is developed for the case of m 2 (x 1 ) finite everywhere in d-dimensional space-time. The case with m 2 (x 1 )=m 0 2 theta((1/2)L-vertical strokex 1 vertical stroke)+msub(infinite) 2 theta(vertical strokex 1 vertical stroke(-1/2)L) is explicitly evaluated for any value of m 0 and msub(infinite) without any approximation. The result consists of volume energy terms, a surface term, and a non-leading term. Most of the UV divergences are in the volume energy terms and renormalize the coupling constants of the underlying theory. The surface energy term is finite for d =5 due to the boundaries being sharp. A closed finite expression is obtained for the non-leading term. Our results are shown to reproduce the known Casimir energies for the limiting cases, m 0 ->infinite and msub(infinite)->infinite. (orig.)
Johnson-Nyquist noise and the Casimir force between real metals at nonzero temperature
International Nuclear Information System (INIS)
Bimonte, Giuseppe
2008-01-01
It has been well known for a long time that all lossy conductors at finite temperature display an electronic noise, the Johnson-Nyquist noise, arising from the thermal agitation of electric charges inside the conductor. The existence of this noise implies that two nearby discharged conductors at finite temperature should repel each other, as a result of the electrodynamic interaction between the Johnson-Nyquist currents in either conductor and the eddy currents they induce in the other. It is suggested that this force is at the origin of the recently discovered large repulsive correction to the thermal Casimir force between two lossy metallic plates. Further support for this physical picture is obtained by studying a simple system of two linear noisy antennas. Using elementary concepts from circuit theory, we show that the repulsive force engendered by the Johnson-Nyquist noise results in the same kind of thermodynamic inconsistencies found in the Casimir problem. We show that all inconsistencies are however resolved if account is taken of capacitive effects associated with the end points of the antennas. Our findings therefore suggest that capacitive effects resulting from the finite size of the plates may be essential for a resolution of the analogous problems met in the thermal Casimir effect
Vortex loops in the critical Casimir effect in superfluid and superconducting films
International Nuclear Information System (INIS)
Williams, Gary A.
2004-01-01
Vortex-loop renormalization techniques are used to calculate the magnitude of the critical Casimir forces in superfluid and superconducting thin films. The force is found to become appreciable when the size of the thermally excited vortex loops is comparable to the film thickness, and the results for T c are found to match very well with perturbative renormalization-group theories that can only be carried out for T>T c . In helium films the Casimir force leads to a change in the film thickness close to T c that has been observed experimentally. A similar effect is predicted to occur near the transition temperature of high-T c superconducting films, which is also a vortex-loop phase transition. In this case the Casimir force takes the form of a voltage difference that will appear at the junction between a thin film and a bulk sample. Estimates show that this voltage can be appreciable (tens of microvolts), and it may be possible to observe the effect by measuring the voltage across two Josephson tunnel junctions to the film and to the bulk, using a SQUID voltmeter
Johnson Nyquist noise and the Casimir force between real metals at nonzero temperature
Bimonte, Giuseppe
2008-04-01
It has been well known for a long time that all lossy conductors at finite temperature display an electronic noise, the Johnson-Nyquist noise, arising from the thermal agitation of electric charges inside the conductor. The existence of this noise implies that two nearby discharged conductors at finite temperature should repel each other, as a result of the electrodynamic interaction between the Johnson-Nyquist currents in either conductor and the eddy currents they induce in the other. It is suggested that this force is at the origin of the recently discovered large repulsive correction to the thermal Casimir force between two lossy metallic plates. Further support for this physical picture is obtained by studying a simple system of two linear noisy antennas. Using elementary concepts from circuit theory, we show that the repulsive force engendered by the Johnson-Nyquist noise results in the same kind of thermodynamic inconsistencies found in the Casimir problem. We show that all inconsistencies are however resolved if account is taken of capacitive effects associated with the end points of the antennas. Our findings therefore suggest that capacitive effects resulting from the finite size of the plates may be essential for a resolution of the analogous problems met in the thermal Casimir effect.
Phillips, Nicholas G.; Hu, B. L.
2000-10-01
We present calculations of the variance of fluctuations and of the mean of the energy momentum tensor of a massless scalar field for the Minkowski and Casimir vacua as a function of an intrinsic scale defined by a smeared field or by point separation. We point out that, contrary to prior claims, the ratio of variance to mean-squared being of the order unity is not necessarily a good criterion for measuring the invalidity of semiclassical gravity. For the Casimir topology we obtain expressions for the variance to mean-squared ratio as a function of the intrinsic scale (defined by a smeared field) compared to the extrinsic scale (defined by the separation of the plates, or the periodicity of space). Our results make it possible to identify the spatial extent where negative energy density prevails which could be useful for studying quantum field effects in worm holes and baby universes, and for examining the design feasibility of real-life ``time machines.'' For the Minkowski vacuum we find that the ratio of the variance to the mean-squared, calculated from the coincidence limit, is identical to the value of the Casimir case at the same limit for spatial point separation while identical to the value of a hot flat space result with a temporal point separation. We analyze the origin of divergences in the fluctuations of the energy density and discuss choices in formulating a procedure for their removal, thus raising new questions about the uniqueness and even the very meaning of regularization of the energy momentum tensor for quantum fields in curved or even flat spacetimes when spacetime is viewed as having an extended structure.
Particle creation by a black hole as a consequence of the Casimir effect
Nugayev, R. M.
1987-12-01
Particle creation by a black hole is investigated in terms of temperature corrections to the Casimir effect. The reduction of the Hawking effect to more familiar effects observed in the laboratory enables us to reveal the mechanism of particle creation. The blackbody nature of the Hawking radiation is due to the interaction of virtual particles with the surface of a “cavity” formed by the Schwarzschild gravitational field potential barrier. These particles are “squeezed out” by the contraction of the potential barrier and appear to an observer at J + as the real blackbody ones.
International Nuclear Information System (INIS)
Xiong, Jie L.; Tong, M.S.; Atkins, Phillip; Chew, W.C.
2010-01-01
In this Letter, we generalized the surface integral equation method for the evaluation of Casimir force in arbitrary three-dimensional geometries. Similar to the two-dimensional case, the evaluation of the mean Maxwell stress tensor is cast into solving a series of three-dimensional scattering problems. The formulation and solution of the three-dimensional scattering problems are well-studied in classical computational electromagnetics. This Letter demonstrates that this quantum electrodynamic phenomenon can be studied using the knowledge and techniques of classical electrodynamics.
Lifshitz-Matsubara sum formula for the Casimir pressure between magnetic metallic mirrors
Guérout, R.; Lambrecht, A.; Milton, K. A.; Reynaud, S.
2016-02-01
We examine the conditions of validity for the Lifshitz-Matsubara sum formula for the Casimir pressure between magnetic metallic plane mirrors. As in the previously studied case of nonmagnetic materials [Guérout et al., Phys. Rev. E 90, 042125 (2014), 10.1103/PhysRevE.90.042125], we recover the usual expression for the lossy model of optical response, but not for the lossless plasma model. We also show that the modes associated with the Foucault currents play a crucial role in the limit of vanishing losses, in contrast to expectations.
Calculation of nonzero-temperature Casimir forces in the time domain
International Nuclear Information System (INIS)
Pan, Kai; Reid, M. T. Homer; McCauley, Alexander P.; Rodriguez, Alejandro W.; White, Jacob K.; Johnson, Steven G.
2011-01-01
We show how to compute Casimir forces at nonzero temperatures with time-domain electromagnetic simulations, for example, using a finite-difference time-domain (FDTD) method. Compared to our previous zero-temperature time-domain method, only a small modification is required, but we explain that some care is required to properly capture the zero-frequency contribution. We validate the method against analytical and numerical frequency-domain calculations, and show a surprising high-temperature disappearance of a nonmonotonic behavior previously demonstrated in a pistonlike geometry.
Thermal corrections to the Casimir energy in a general weak gravitational field
Nazari, Borzoo
2016-12-01
We calculate finite temperature corrections to the energy of the Casimir effect of a two conducting parallel plates in a general weak gravitational field. After solving the Klein-Gordon equation inside the apparatus, mode frequencies inside the apparatus are obtained in terms of the parameters of the weak background. Using Matsubara’s approach to quantum statistical mechanics gravity-induced thermal corrections of the energy density are obtained. Well-known weak static and stationary gravitational fields are analyzed and it is found that in the low temperature limit the energy of the system increases compared to that in the zero temperature case.
Nori, Franco
2012-02-01
This talk will present an overview of some of our recent results on atomic physics and quantum optics using superconducting circuits. Particular emphasis will be given to photons interacting with qubits, interferometry, the Dynamical Casimir effect, and also studying Majorana fermions using superconducting circuits.[4pt] References available online at our web site:[0pt] J.Q. You, Z.D. Wang, W. Zhang, F. Nori, Manipulating and probing Majorana fermions using superconducting circuits, (2011). Arxiv. J.R. Johansson, G. Johansson, C.M. Wilson, F. Nori, Dynamical Casimir effect in a superconducting coplanar waveguide, Phys. Rev. Lett. 103, 147003 (2009). [0pt] J.R. Johansson, G. Johansson, C.M. Wilson, F. Nori, Dynamical Casimir effect in superconducting microwave circuits, Phys. Rev. A 82, 052509 (2010). [0pt] C.M. Wilson, G. Johansson, A. Pourkabirian, J.R. Johansson, T. Duty, F. Nori, P. Delsing, Observation of the Dynamical Casimir Effect in a superconducting circuit. Nature, in press (Nov. 2011). P.D. Nation, J.R. Johansson, M.P. Blencowe, F. Nori, Stimulating uncertainty: Amplifying the quantum vacuum with superconducting circuits, Rev. Mod. Phys., in press (2011). [0pt] J.Q. You, F. Nori, Atomic physics and quantum optics using superconducting circuits, Nature 474, 589 (2011). [0pt] S.N. Shevchenko, S. Ashhab, F. Nori, Landau-Zener-Stuckelberg interferometry, Phys. Reports 492, 1 (2010). [0pt] I. Buluta, S. Ashhab, F. Nori. Natural and artificial atoms for quantum computation, Reports on Progress in Physics 74, 104401 (2011). [0pt] I.Buluta, F. Nori, Quantum Simulators, Science 326, 108 (2009). [0pt] L.F. Wei, K. Maruyama, X.B. Wang, J.Q. You, F. Nori, Testing quantum contextuality with macroscopic superconducting circuits, Phys. Rev. B 81, 174513 (2010). [0pt] J.Q. You, X.-F. Shi, X. Hu, F. Nori, Quantum emulation of a spin system with topologically protected ground states using superconducting quantum circuit, Phys. Rev. A 81, 063823 (2010).
Casimir problem of spherical dielectrics: quantum statistical and field theoretical approaches.
Høye, J S; Brevik, I; Aarseth, J B
2001-05-01
The Casimir free energy for a system of two dielectric concentric nonmagnetic spherical bodies is calculated with use of a quantum statistical mechanical method, at arbitrary temperature. By means of this rather novel method, which turns out to be quite powerful (we have shown this to be true in other situations also), we consider first an explicit evaluation of the free energy for the static case, corresponding to zero Matsubara frequency (n=0). Thereafter, the time-dependent case is examined. For comparison we consider the calculation of the free energy with use of the more commonly known field theoretical method, assuming for simplicity metallic boundary surfaces.
Palasantzas, George
2007-01-01
In this work, we investigate the combined influence of electromagnetic and acoustic Casimir forces on the pull-in voltage of microswitches with self-affine rough plates. It is shown that for plate separations within the micron range the acoustic term arising from pressure fluctuations can influence
Casimir energies in M4≥/sup N/ for even N. Green's-function and zeta-function techniques
International Nuclear Information System (INIS)
Kantowski, R.; Milton, K.A.
1987-01-01
The Green's-function technique developed in the first paper in this series is generalized to apply to massive scalar, vector, second-order tensor, and Dirac spinor fields, as a preliminary to a full graviton calculation. The Casimir energies are of the form u/sub Casimir/ = (1/a 4 )[α/sub N/lna/b)+β/sub N/], where N (even) is the dimension of the internal sphere, a is its radius, and b/sup -1/ is an ultraviolet cutoff (presumably at the Planck scale). The coefficient of the divergent logarithm, α/sub N/, is unambiguously obtained for each field considered. The Green's-function technique gives rise to no difficulties in the evaluation of imaginary-mass-mode contributions to the Casimir energy. In addition, a new, simplified zeta-function technique is presented which is very easily implemented by symbolic programs, and which, of course, gives the same results. An error in a previous zeta-function calculation of the Casimir energy for even N is pointed out
Plasma versus Drude Modeling of the Casimir Force: Beyond the Proximity Force Approximation
Hartmann, Michael; Ingold, Gert-Ludwig; Neto, Paulo A. Maia
2017-07-01
We calculate the Casimir force and its gradient between a spherical and a planar gold surface. Significant numerical improvements allow us to extend the range of accessible parameters into the experimental regime. We compare our numerically exact results with those obtained within the proximity force approximation (PFA) employed in the analysis of all Casimir force experiments reported in the literature so far. Special attention is paid to the difference between the Drude model and the dissipationless plasma model at zero frequency. It is found that the correction to PFA is too small to explain the discrepancy between the experimental data and the PFA result based on the Drude model. However, it turns out that for the plasma model, the corrections to PFA lie well outside the experimental bound obtained by probing the variation of the force gradient with the sphere radius [D. E. Krause et al., Phys. Rev. Lett. 98, 050403 (2007), 10.1103/PhysRevLett.98.050403]. The corresponding corrections based on the Drude model are significantly smaller but still in violation of the experimental bound for small distances between plane and sphere.
International Nuclear Information System (INIS)
Kim, W J; Brown-Hayes, M; Brownell, J H; Dalvit, D A R; Onofrio, R
2009-01-01
We report on measurements of forces acting between two conducting surfaces in a spherical-plane configuration in the 35 nm-1 μm separation range. The measurements are obtained by performing electrostatic calibrations followed by a residuals analysis after subtracting the electrostatic-dependent component. We find in all runs optimal fitting of the calibrations for exponents smaller than the one predicted by electrostatics for an ideal sphere-plane geometry. We also find that the external bias potential necessary to minimize the electrostatic contribution depends on the sphere-plane distance. In spite of these anomalies, by implementing a parametrization-dependent subtraction of the electrostatic contribution we have found evidence for short-distance attractive forces of magnitude comparable to the expected Casimir-Lifshitz force. We finally discuss the relevance of our findings in the more general context of Casimir-Lifshitz force measurements, with particular regard to the critical issues of the electrical and geometrical characterization of the involved surfaces.
The generalized Abel-Plana formula. Applications to Bessel functions and Casimir effect
International Nuclear Information System (INIS)
Saharian, A.A.; Institute of Applied Problems in Physics NAS RA, Yerevan; Abdus Salam International Centre for Theoretical Physics, Trieste
2000-02-01
One of the most efficient methods to obtain the vacuum expectation values for the physical observables in the Casimir effect is based on using the Abel-Plana summation formula. This allows us to derive the regularized quantities in a manifestly cutoff independent way and present them in the form of strongly convergent integrals. However, the application of Abel-Plana formula, in its usual form, is restricted by simple geometries when the eigenmodes have a simple dependence on quantum numbers. The author generalized the Abel-Plana formula which essentially enlarges its application range. Based on this generalization, formulae have been obtained for various types of series over the zeros of some combinations of Bessel functions and for integrals involving these functions. It has been shown that these results generalize the special cases existing in literature. Further, the derived summation formulae have been used to summarize series arising in the mode summation approach to the Casimir effect for spherically and cylindrically symmetric boundaries. This allows us to extract the divergent parts from the vacuum expectation values for the local physical observables in a manifestly cutoff independent way. The present paper reviews these results. Some new considerations are also added. (author)
Free vibration of geometrically nonlinear micro-switches under electrostatic and Casimir forces
International Nuclear Information System (INIS)
Jia, X L; Kitipornchai, S; Lim, C W; Yang, J
2010-01-01
This paper investigates the free vibration characteristics of micro-switches under combined electrostatic, intermolecular forces and axial residual stress, with an emphasis on the effect of geometric nonlinear deformation due to mid-plane stretching and the influence of Casimir force. The micro-switch considered in this study is made of either homogeneous material or non-homogeneous functionally graded material with two material phases. The Euler–Bernoulli beam theory with von Karman type nonlinear kinematics is applied in the theoretical formulation. The principle of virtual work is used to derive the nonlinear governing differential equation. The eigenvalue problem which describes free vibration of the micro-beam at its statically deflected state is then solved using the differential quadrature method. The natural frequencies and mode shapes of micro-switches for four different boundary conditions (i.e. clamped–clamped, clamped–simply supported, simply supported and clamped–free) are obtained. The solutions are validated through direct comparisons with experimental and other existing results reported in previous studies. A parametric study is conducted to show the significant effects of geometric nonlinearity, Casimir force, axial residual stress and material composition for the natural frequencies
The trace identity and the planar Casimir effect
Indian Academy of Sciences (India)
S G Kamath the derivative operators in (24) acting on ∆(x−y), the latter being now defined by. (18a) but with the δ-function appropriate to three space–time dimensions. Rewrit- ing (24) as exp iZ[J(x),Kµ,Dαβ,Lµν]. = 1. W0. ∞. ∑. 0. (−i)n n! {∫. d3yDµν(y)Gµν. }n. × exp −. {. 1. 2 i. ∫. d3xd3yM(x)∆(x − y)M(y). } (25) with. Gµν = 3.
Reply to 'Comment on 'Temperature dependence of the Casimir force for lossy bulk media''
Energy Technology Data Exchange (ETDEWEB)
Yampol' skii, V. A.; Maizelis, Z. A.; Apostolov, S. S. [Advanced Science Institute, RIKEN, Saitama, 351-0198 (Japan); A. Ya. Usikov Institute for Radiophysics and Electronics, NASU, 61085 Kharkov (Ukraine); Savel' ev, Sergey [Advanced Science Institute, RIKEN, Saitama, 351-0198 (Japan); Department of Physics, Loughborough University, Loughborough LE11 3TU (United Kingdom); Nori, Franco [Advanced Science Institute, RIKEN, Saitama, 351-0198 (Japan); Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2011-09-15
Here, we present an estimate of the characteristic wavelengths of the evanescent modes, which define the main contribution to the thermal part of the Casimir force. This estimate is more precise than the one in the preceding Comment by Bimonte et al.[Phys. Rev. A 84, 036501 (2011)]. The wavelengths we derive are indeed smaller than the sizes of the interacting bodies. We also discuss the results of several experiments on the thermal effects in the Casimir force.
Henkel, C.; Klimchitskaya, G. L.; Mostepanenko, V. M.
2018-03-01
We present a formalism based on first principles of quantum electrodynamics at nonzero temperature which permits us to calculate the Casimir-Polder interaction between an atom and a graphene sheet with arbitrary mass gap and chemical potential, including graphene-coated substrates. The free energy and force of the Casimir-Polder interaction are expressed via the polarization tensor of graphene in (2 +1 ) -dimensional space-time in the framework of the Dirac model. The obtained expressions are used to investigate the influence of the chemical potential of graphene on the Casimir-Polder interaction. Computations are performed for an atom of metastable helium interacting with either a freestanding graphene sheet or a graphene-coated substrate made of amorphous silica. It is shown that the impacts of the nonzero chemical potential and the mass gap on the Casimir-Polder interaction are in opposite directions, by increasing and decreasing the magnitudes of the free energy and force, respectively. It turns out, however, that the temperature-dependent part of the Casimir-Polder interaction is decreased by a nonzero chemical potential, whereas the mass gap increases it compared to the case of undoped, gapless graphene. The physical explanation for these effects is provided. Numerical computations of the Casimir-Polder interaction are performed at various temperatures and atom-graphene separations.
Casimir Forces and Quantum Friction from Ginzburg Radiation in Atomic Bose-Einstein Condensates.
Marino, Jamir; Recati, Alessio; Carusotto, Iacopo
2017-01-27
We theoretically propose an experimentally viable scheme to use an impurity atom in an atomic Bose-Einstein condensate, in order to realize condensed-matter analogs of quantum vacuum effects. In a suitable atomic level configuration, the collisional interaction between the impurity atom and the density fluctuations in the condensate can be tailored to closely reproduce the electric-dipole coupling of quantum electrodynamics. By virtue of this analogy, we recover and extend the paradigm of electromagnetic vacuum forces to the domain of cold atoms, showing in particular the emergence, at supersonic atomic speeds, of a novel power-law scaling of the Casimir force felt by the atomic impurity, as well as the occurrence of a quantum frictional force, accompanied by the Ginzburg emission of Bogoliubov quanta. Observable consequences of these quantum vacuum effects in realistic spectroscopic experiments are discussed.
Gauge dynamics in the PNJL model: Color neutrality and Casimir scaling
International Nuclear Information System (INIS)
Abuki, Hiroaki; Fukushima, Kenji
2009-01-01
We discuss a gauge-invariant prescription to take the mean-field approximation self-consistently in the PNJL model (Nambu-Jona-Lasinio model with the Polyakov loop). We first address the problem of non-vanishing color density in normal quark matter, which is an artifact arising from gauge-fixed treatment of the Polyakov loop mean-fields. We then confirm that the gauge average incorporated in our prescription resolves this problem and ensures color neutrality. We point out that the proposed method has an advantage in computing the expectation value of any function of the Polyakov loop matrix. We discuss the Casimir scaling as an immediate application of the method.
Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom
White, Harold; Vera, Jerry; Bailey, Paul; March, Paul; Lawrence, Tim; Sylvester, Andre; Brady, David
2015-01-01
This paper will discuss the current viewpoint of the vacuum state and explore the idea of a "natural" vacuum as opposed to immutable, non-degradable vacuum. This concept will be explored for all primary quantum numbers to show consistency with observation at the level of Bohr theory. A comparison with the Casimir force per unit area will be made, and an explicit function for the spatial variation of the vacuum density around the atomic nucleus will be derived. This explicit function will be numerically modeled using the industry multi-physics tool, COMSOL(trademark), and the eigenfrequencies for the n = 1 to n = 7 states will be found and compared to expectation.
Irreversible dynamics, Onsager-Casimir symmetry, and an application to turbulence.
Ottinger, Hans Christian
2014-10-01
Irreversible contributions to the dynamics of nonequilibrium systems can be formulated in terms of dissipative, or irreversible, brackets. We discuss the structure of such irreversible brackets in view of a degeneracy implied by energy conservation, where we consider different types of symmetries of the bracket corresponding to the Onsager and Casimir symmetries of linear irreversible thermodynamics. Slip and turbulence provide important examples of antisymmetric irreversible brackets and offer guidance for the more general modeling of irreversible dynamics without entropy production. Conversely, turbulence modeling could benefit from elucidating thermodynamic structure. The examples suggest constructing antisymmetric irreversible brackets in terms of completely antisymmetric functions of three indices. Irreversible brackets without well-defined symmetry properties can arise for rare events, causing big configurational changes.
Lateral Casimir-Polder forces by breaking time-reversal symmetry
Oude Weernink, Ricardo R. Q. P. T.; Barcellona, Pablo; Buhmann, Stefan Yoshi
2018-03-01
We examine the lateral Casimir-Polder force acting on a circular rotating emitter near a dielectric plane surface. As the circular motion breaks time-reversal symmetry, the spontaneous emission in a direction parallel to the surface is in general anisotropic. We show that a lateral force arises which can be interpreted as a recoil force because of this asymmetric emission. The force is an oscillating function of the distance between the emitter and the surface, and the lossy character of the dielectric strongly influences the results in the near-field regime. The force exhibits also a population-induced dynamics, decaying exponentially with respect to time on time scales of the inverse of the spontaneous decay rate. We propose that this effect could be detected measuring the velocity acquired by the emitter, following different cycles of excitation and spontaneous decay. Our results are expressed in terms of the Green's tensor and can therefore easily be applied to more complex geometries.
Brevik, Iver
2012-09-01
The main part of this paper is to present an updated review of the Casimir energy at zero and finite temperature for the transverse oscillations of a piecewise uniform closed string. We make use of three different regularizations: the cutoff method, the complex contour integration method and the zeta-function method. The string model is relativistic, in the sense that the velocity of sound is for each string piece set equal to the velocity of light. In this sense the theory is analogous to the electromagnetic theory in a dielectric medium in which the product of permittivity and permeability is equal to unity (an isorefractive medium). We demonstrate how the formalism works for a two-piece string, and for a 2N-piece string, and show how in the latter case a compact recursion relation serves to facilitate the formalism considerably. The Casimir energy turns out to be negative, and the more so the larger the number of pieces in the string. The two-piece string is quantized in D-dimensional spacetime, in the limit when the ratio between the two tensions is very small. We calculate the free energy and other thermodynamic quantities, demonstrate scaling properties, and comment finally on the meaning of the Hagedorn critical temperature for the two-piece string. Thereafter, as a novel development we present a scalar field theory for a real field in three-dimensional space in a potential rising linearly with a longitudinal coordinate z in the interval 0 birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.
International Nuclear Information System (INIS)
Lim, S C; Teo, L P
2007-01-01
We derive rigorously explicit formulae of the Casimir free energy at finite temperature for massless scalar field and electromagnetic field confined in a closed rectangular cavity with different boundary conditions by a zeta regularization method. We study both the low and high temperature expansions of the free energy. In each case, we write the free energy as a sum of a polynomial in temperature plus exponentially decay terms. We show that the free energy is always a decreasing function of temperature. In the cases of massless scalar field with the Dirichlet boundary condition and electromagnetic field, the zero temperature Casimir free energy might be positive. In each of these cases, there is a unique transition temperature (as a function of the side lengths of the cavity) where the Casimir energy changes from positive to negative. When the space dimension is equal to two and three, we show graphically the dependence of this transition temperature on the side lengths of the cavity. Finally we also show that we can obtain the results for a non-closed rectangular cavity by letting the size of some directions of a closed cavity go to infinity, and we find that these results agree with the usual integration prescription adopted by other authors
International Nuclear Information System (INIS)
Rego, Andreson L.C.; Farina, Carlos; Alves, J.P.S.; Alves, Danilo T.
2012-01-01
Full text: The creation of real particles from vacuum induced by moving mirrors with non-uniform acceleration is a quantum vacuum effect usually called dynamical Casimir effect (DCE). The radiation reaction force acting on this moving plate is an alternative manner to explain this fascinating effect. The theoretical prediction of the DCE was made by Moore in 1970 (J Math. Phys. 11, 2679, (1970)), considering a cavity with a moving boundary, and a real massless scalar field in a two-dimensional space-time. DeWitt (Phys. Rep. 19, 295 (1975)), Fulling and Davies (Proc. R. Soc. London, A 348, 393 (1976)) also investigated the DCE with the same two-dimensional model, but with just a single moving mirror, the simplest way to produce the Casimir radiation. The experimental measure of the DCE can be treated as a direct confirmation of existence of vacuum fluctuations. In the single mirror problem, for realistic parameters, the amount of created particles is not appreciable. In order to remove this difficulty, several experimental proposals were presented to detect the radiation generated by the DCE. More than 40 years after its first theoretical prediction, the DCE was observed by Wilson and collaborators (Nature, 479, 376, (2011)) in the context of circuit Quantum Electrodynamics (circuit-QED). The experiment was based on a superconducting circuit consisting in a coplanar waveguide terminated by a SQUID (a sensitive magnetometer). The presence of time-dependent magnetic fluxes enable fast modulations in the electrical length of the transmission line. This setup simulates a moving mirror whose effective velocity can achieve 0:1 of velocity of light. In the present work, taking into account the fact of the effective velocity implemented on the first experimental observation of the DCE is a substantial fraction of velocity of light, we investigate relativistic effects in the particle creation via DCE in a superconducting circuit. Considering a massless scalar field in 1
International Nuclear Information System (INIS)
Fosco, Cesar D.; Lombardo, Fernando C.
2015-01-01
We study the properties of the classical electromagnetic radiation produced by two physically different yet closely related systems, which may be regarded as classical analogues of the dynamical Casimir effect. They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect-conductor boundary conditions, while the other performs a rigid oscillatory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written in terms of the dipole layer autocorrelation function. We show that there are resonances as a function of the frequency of the mechanical oscillation. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Fosco, Cesar D. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, Instituto Balseiro, Bariloche (Argentina); Lombardo, Fernando C. [Ciudad Universitaria, Departamento de Fisica Juan Jose Giambiagi, FCEyN UBA y IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina)
2015-12-15
We study the properties of the classical electromagnetic radiation produced by two physically different yet closely related systems, which may be regarded as classical analogues of the dynamical Casimir effect. They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect-conductor boundary conditions, while the other performs a rigid oscillatory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written in terms of the dipole layer autocorrelation function. We show that there are resonances as a function of the frequency of the mechanical oscillation. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Fosco, César D. [Centro Atómico Bariloche, Instituto Balseiro, Comisión Nacional de Energía Atómica, R8402AGP, Bariloche (Argentina); Lombardo, Fernando C., E-mail: lombardo@df.uba.ar [Departamento de Física Juan José Giambiagi, FCEyN UBA and IFIBA CONICET-UBA, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Pabellón I, 1428, Buenos Aires (Argentina)
2015-12-17
We study the properties of the classical electromagnetic radiation produced by two physically different yet closely related systems, which may be regarded as classical analogues of the dynamical Casimir effect. They correspond to two flat, infinite, parallel planes, one of them static and imposing perfect-conductor boundary conditions, while the other performs a rigid oscillatory motion. The systems differ just in the electrical properties of the oscillating plane: one of them is just a planar dipole layer (representing, for instance, a small-width electret). The other, instead, has a dipole layer on the side which faces the static plane, but behaves as a conductor on the other side: this can be used as a representation of a conductor endowed with patch potentials (on the side which faces the conducting plane). We evaluate, in both cases, the dissipative flux of energy between the system and its environment, showing that, at least for small mechanical oscillation amplitudes, it can be written in terms of the dipole layer autocorrelation function. We show that there are resonances as a function of the frequency of the mechanical oscillation.
De vette jaren: de Commissie-Casimir en het Nederlandse wetenschapsbeleid 1957-1970
Directory of Open Access Journals (Sweden)
David Baneke
2012-11-01
Full Text Available The Years of Abundance: the Casimir Committee and Dutch Science Policy 1957–1970 In October 1958, a committee of six prominent Dutch scientists and industrial managers presented a brief report in which they requested a major increase of the science budget. This report has been described as a turning point in the history of science in the Netherlands, signaling the beginning of a decade of rapid growth of funding for ‘pure’ research. Surprisingly little is known about the backgrounds of this report, however. In this paper, I analyze its origin, its relation to contemporary higher education policy, and its consequences. As it turns out, the report was less revolutionary than is usually assumed: it mostly reinforced developments that had already begun earlier. Furthermore, Sputnik and the Cold War were not as important as is often claimed. This paper also suggests a reinterpretation of the justification of the government spending on academic research after the Second World War. Producing skilled researchers for industry was at least as important as produc- ing new knowledge.
Casimir meets Poisson: improved quark/gluon discrimination with counting observables
Frye, Christopher; Larkoski, Andrew J.; Thaler, Jesse; Zhou, Kevin
2017-09-01
Charged track multiplicity is among the most powerful observables for discriminating quark- from gluon-initiated jets. Despite its utility, it is not infrared and collinear (IRC) safe, so perturbative calculations are limited to studying the energy evolution of multiplicity moments. While IRC-safe observables, like jet mass, are perturbatively calculable, their distributions often exhibit Casimir scaling, such that their quark/gluon discrimination power is limited by the ratio of quark to gluon color factors. In this paper, we introduce new IRC-safe counting observables whose discrimination performance exceeds that of jet mass and approaches that of track multiplicity. The key observation is that track multiplicity is approximately Poisson distributed, with more suppressed tails than the Sudakov peak structure from jet mass. By using an iterated version of the soft drop jet grooming algorithm, we can define a "soft drop multiplicity" which is Poisson distributed at leading-logarithmic accuracy. In addition, we calculate the next-to-leading-logarithmic corrections to this Poisson structure. If we allow the soft drop groomer to proceed to the end of the jet branching history, we can define a collinear-unsafe (but still infrared-safe) counting observable. Exploiting the universality of the collinear limit, we define generalized fragmentation functions to study the perturbative energy evolution of collinear-unsafe multiplicity.
Directory of Open Access Journals (Sweden)
Agnieszka Skrodzka
2016-12-01
Full Text Available The young Casimir Vasa was brought up at the court of his father, Sigismund III Vasa, in the atmosphere of great devotion, which made him enter the order of Jesuits. Even though he decided to leave the monastery and to take the Polish crown, he came back to the life of a monk after his abdication. The present paper presents the very few pieces of art commemorating the monastic life of John Casimir: an emblem, a medal, some prints and his tomb in Paris. All those objects demonstrate the deep piety of the king.
The Casimir Effect from the Point of View of Algebraic Quantum Field Theory
Energy Technology Data Exchange (ETDEWEB)
Dappiaggi, Claudio, E-mail: claudio.dappiaggi@unipv.it; Nosari, Gabriele [Università degli Studi di Pavia, Dipartimento di Fisica (Italy); Pinamonti, Nicola [Università di Genova, Dipartimento di Matematica (Italy)
2016-06-15
We consider a region of Minkowski spacetime bounded either by one or by two parallel, infinitely extended plates orthogonal to a spatial direction and a real Klein-Gordon field satisfying Dirichlet boundary conditions. We quantize these two systems within the algebraic approach to quantum field theory using the so-called functional formalism. As a first step we construct a suitable unital ∗-algebra of observables whose generating functionals are characterized by a labelling space which is at the same time optimal and separating and fulfils the F-locality property. Subsequently we give a definition for these systems of Hadamard states and we investigate explicit examples. In the case of a single plate, it turns out that one can build algebraic states via a pull-back of those on the whole Minkowski spacetime, moreover inheriting from them the Hadamard property. When we consider instead two plates, algebraic states can be put in correspondence with those on flat spacetime via the so-called method of images, which we translate to the algebraic setting. For a massless scalar field we show that this procedure works perfectly for a large class of quasi-free states including the Poincaré vacuum and KMS states. Eventually Wick polynomials are introduced. Contrary to the Minkowski case, the extended algebras, built in globally hyperbolic subregions can be collected in a global counterpart only after a suitable deformation which is expressed locally in terms of a *-isomorphism. As a last step, we construct explicitly the two-point function and the regularized energy density, showing, moreover, that the outcome is consistent with the standard results of the Casimir effect.
From optical lattice clocks to the measurement of forces in the Casimir regime
International Nuclear Information System (INIS)
Wolf, Peter; Lemonde, Pierre; Bize, Sebastien; Landragin, Arnaud; Clairon, Andre; Lambrecht, Astrid
2007-01-01
We describe an experiment based on atoms trapped close to a macroscopic surface, to study the interactions between the atoms and the surface at very small separations (0.6-10 μm). In this range the dominant potential is the QED interaction (Casimir-Polder and van der Waals) between the surface and the atom. Additionally, several theoretical models suggest the possibility of Yukawa-type potentials with sub-millimeter range, arising from new physics related to gravity. The proposed setup is very similar to neutral atom optical lattice clocks, but with the atoms trapped in lattice sites close to the reflecting mirror. A sequence of pulses of the probe laser at different frequencies is then used to create an interferometer with a coherent superposition between atomic states at different distances from the mirror (in different lattice sites). Assuming atom interferometry state-of-the-art measurement of the phase difference and a duration of the superposition of about 0.1 s, we expect to be able to measure the potential difference between separated states with an uncertainty of ≅10 -4 Hz. An analysis of systematic effects for different atoms and surfaces indicates no fundamentally limiting effect at the same level of uncertainty, but does influence the choice of atom and surface material. Based on those estimates, we expect that such an experiment would improve the best existing measurements of the atom-wall QED interaction by ≥ 2 orders of magnitude, while gaining up to four orders of magnitude on the best present limits on new interactions in the range between 100 nm and 100 μm
Thermal Casimir-Polder forces on a V-type three-level atom
Xu, Chen-Ran; Xu, Jing-Ping; Al-amri, M.; Zhu, Cheng-Jie; Xie, Shuang-Yuan; Yang, Ya-Ping
2017-09-01
We study the thermal Casimir-Polder (CP) forces on a V-type three-level atom. The competition between the thermal effect and the quantum interference of the two transition dipoles on the force is investigated. To shed light onto the role of the quantum interference, we analyze two kinds of initial states of the atom, i.e., the superradiant state and the subradiant state. Considering the atom being in the thermal reservoir, the resonant CP force arising from the real photon emission dominates in the evolution of the CP force. Under the zero-temperature condition, the quantum interference can effectively modify the amplitude and the evolution of the force, leading to a long-time force or even the cancellation of the force. Our results reveal that in the finite-temperature case, the thermal photons can enhance the amplitude of all force elements, but have no influence on the net resonant CP force in the steady state, which means that the second law of thermodynamics still works. For the ideal degenerate V-type atom with parallel dipoles under the initial subradiant state, the robust destructive quantum interference overrides the thermal fluctuations, leading to the trapping of the atom in the subradiant state and the disappearance of the CP force. However, in terms of a realistic Zeeman atom, the thermal photons play a significant role during the evolution of the CP force. The thermal fluctuations can enhance the amplitude of the initial CP force by increasing the temperature, and weaken the influence of the quantum interference on the evolution of the CP force from the initial superradiant (subradiant) state to the steady state.
Directory of Open Access Journals (Sweden)
Michael A. Persinger
2015-09-01
Full Text Available The ~1.5 × 10−20 J which is considered a universal quantity and is associated with the movement of protons in water also relates to the ratio of the magnetic moment of a proton divided by its unit charge, multiplied by viscosity and applied over the O-H distance. There is quantitative evidence that thixotropy, the “spontaneous” increased viscosity in water when undisturbed, originates from the transformation of virtual particles or vacuum oscillations to real states through conversion of Casimir-magnetic energies that involve the frequency of the neutral hydrogen line and the upper bound threshold value for intergalactic magnetic fields. The results indicate that ½ of a single electron orbit is real (particle and the other ½ is virtual (wave. The matter equivalent per s for virtual-to-real states for electrons in 1 mL of water with a neutral pH is consistent with the numbers of protons (H+ and the measured range of molecules in the coherent domains for both width and duration of growth and is similar to widths of intergalactic dust grains from which planets and stars may condense. The de Broglie momentum for the lower boundary of the width of coherent domains multiplied by the fine structure velocity of an electron is concurrent with the quantum when one proton is being removed from another and when the upper boundary of the rest mass of a photon is transformed by the product of velocities for putative “entanglement” and light. Theoretical and experimental results indicate that components of thixotropy, such as specific domains of intercalated water molecules, could display excess correlations over very large distances. Because the energies of the universal quantity and water converge it may be a special conduit for discrete transformations from virtual to real states.
Okamoto, Ryuichi; Onuki, Akira
2012-03-21
We investigate the critical behavior of a near-critical fluid confined between two parallel plates in contact with a reservoir by calculating the order parameter profile and the Casimir amplitudes (for the force density and for the grand potential). Our results are applicable to one-component fluids and binary mixtures. We assume that the walls absorb one of the fluid components selectively for binary mixtures. We propose a renormalized local functional theory accounting for the fluctuation effects. Analysis is performed in the plane of the temperature T and the order parameter in the reservoir ψ(∞). Our theory is universal if the physical quantities are scaled appropriately. If the component favored by the walls is slightly poor in the reservoir, there appears a line of first-order phase transition of capillary condensation outside the bulk coexistence curve. The excess adsorption changes discontinuously between condensed and noncondensed states at the transition. With increasing T, the transition line ends at a capillary critical point T=T(c) (ca) slightly lower than the bulk critical temperature T(c) for the upper critical solution temperature. The Casimir amplitudes are larger than their critical point values by 10-100 times at off-critical compositions near the capillary condensation line. © 2012 American Institute of Physics
Energy Technology Data Exchange (ETDEWEB)
Fischer, D.J.
2008-01-15
We study the Casimir energy density of the Klein-Gordon-field in the case of two static geometries. We model the effect by coupling the free quantum field to a static classical scalar field. We work out the dependence on the coupling {lambda}, including the limit {lambda}={infinity} (Dirichlet boundary condition). The chosen geometries are described by a {delta}-funktion ({sigma}(x)={delta}(x{sub 3})) and a step function of finite height ({sigma}(x)= (1)/(2{epsilon})1{sub [{epsilon},{epsilon}]}(x{sub 3})), respectively. In the area outside the support of the background the density energy converges; calculations for the distorted area lead to divergent surface terms. (orig.)
International Nuclear Information System (INIS)
Mostepanenko, V M; Babb, J F; Caride, A O; Klimchitskaya, G L; Zanette, S I
2006-01-01
The Casimir-Polder and van der Waals interactions between an atom and a flat cavity wall are investigated under the influence of real conditions including the dynamic polarizability of the atom, actual conductivity of the wall material and nonzero temperature of the wall. The cases of different atoms near metal and dielectric walls are considered. It is shown that to obtain accurate results for the atom-wall interaction at short separations, one should use the complete tabulated optical data for the complex refractive index of the wall material and the accurate dynamic polarizability of an atom. At relatively large separations in the case of a metal wall, one may use the plasma model dielectric function to describe the dielectric properties of the wall material. The obtained results are important for the theoretical interpretation of experiments on quantum reflection and Bose-Einstein condensation
Directory of Open Access Journals (Sweden)
Amir R. Askari
2014-01-01
Full Text Available The influence of the Casimir excitation on dynamic pull-in instability of a nanoelectromechanical beam under ramp-input voltage is studied. The ramp-input actuation has applications in frequency sweeping of RF-N/MEMS. The presented model is nonlinear due to the inherent nonlinearity of electrostatics and the Casimir excitations as well as the geometric nonlinearity of midplane stretching. A Galerkin based reduced order modeling is utilized. It is found that the calculated dynamic pull-in ramp input voltage leads to dynamic pull-in step input voltage by increasing the slope of voltage-time diagram. This fact is utilized to verify the results of present study.
International Nuclear Information System (INIS)
Soroush, R; Koochi, A; Haddadpour, H; Kazemi, A S; Noghrehabadi, A; Abadyan, M
2010-01-01
This paper investigates the effect of dispersion (van der Waals and Casimir) forces on the pull-in instability of cantilever nano-actuators by considering their range of application. Adomian decomposition is introduced to obtain an analytical solution of the distributed parameter model. Dispersion forces decrease the pull-in deflection and voltage of a nano-actuator. However, the fringing field increases the pull-in deflection while decreasing the pull-in voltage of the actuator. The minimum initial gap and the detachment length of the actuator that does not stick to the substrate due to van der Waals and Casimir attractions were determined. Furthermore, the proposed approach is capable of determining the stress distribution of the actuator at the onset of instability. It is seen that Casimir and van der Waals attractions effectively reduce the maximum value of stress resultants at the onset of instability. The results indicate that Adomian decomposition is a reliable method for simulating nano-structures at submicrometer ranges.
Rodrigues, Janderson R; Gusso, Andre; Rosa, Felipe S S; Almeida, Vilson R
2018-02-22
Nano-optomechanical devices have enabled a lot of interesting scientific and technological applications. However, due to their nanoscale dimensions, they are vulnerable to the action of Casimir and van der Waals (dispersion) forces. This work presents a rigorous analysis of the dispersion forces on a nano-optomechanical device based on a silicon waveguide and a silicon dioxide substrate, surrounded by air and driven by optical forces. The dispersion forces are calculated using a modified Lifshitz theory with experimental optical data and validated by means of a rigorous 3D FDTD simulation. The mechanical nonlinearity of the nanowaveguide is taken into account and validated using a 3D FEM simulation. The results show that it is possible to attain a no pull-in critical point due to only the optical forces; however, the dispersion forces usually impose a pull-in critical point to the device and establish a minimal initial gap between the waveguide and the substrate. Furthermore, it is shown that the geometric nonlinearity effect may be exploited in order to avoid or minimize the pull-in and, therefore, the device collapse.
International Nuclear Information System (INIS)
Barut, A.O.; Dowling, J.P.
1986-12-01
Using a previously formulated theory of quantum electrodynamics based on self-energy, we give a general method for computing the Lamb shift and related Casimir-Polder energies for a quantum system in the vicinity of perfectly conducting boundaries. Our results are exact and easily extendable to a full covariant relativistic form. As a particular example we apply the method to an atom near an infinite conducting plane, and we recover the standard QED results (which are known only in the dipole approximation) in a simple and straightforward manner. This is accomplished in the context of the new theory which is not second quantized and contains no vacuum fluctuations. (author)
Fermions on the low-buckled honey-comb structured lattice plane and classical Casimir-Polder force
Goswami, Partha
2016-05-01
We start with the well-known expression for the vacuum polarization and suitably modify it for 2+1-dimensional spin-orbit coupled (SOC) fermions on the low-buckled honey-comb structured lattice plane described by the low-energy Liu-Yao-Feng-Ezawa (LYFE) model Hamiltonian involving the Dirac matrices in the chiral representation obeying the Clifford algebra. The silicene and germanene fit this description suitably. They have the Dirac cones similar to those of graphene and SOC is much stronger. The system could be normal or ferromagnetic in nature. The silicene turns into the latter type if there is exchange field arising due to the proximity coupling to a ferromagnet (FM) such as depositing Fe atoms to the silicene surface. For the silicene, we find that the many-body effects considerably change the bare Coulomb potential by way of the dependence of the Coulomb propagator on the real-spin, iso-spin and the potential due to an electric field applied perpendicular to the silicene plane. The computation aspect of the Casimir-Polder force (CPF) needs to be investigated in this paper. An important quantity in this process is the dielectric response function (DRF) of the material. The plasmon branch was obtained by finding the zeros of DRF in the long-wavelength limit. This leads to the plasmon frequencies. We find that the collective charge excitations at zero doping, i.e., intrinsic plasmons, in this system, are absent in the Dirac limit. The valley-spin-split intrinsic plasmons, however, come into being in the case of the massive Dirac particles with characteristic frequency close to 10 THz. Our scheme to calculate the Casimir-Polder interaction (CPI) of a micro-particle with a sheet involves replacing the dielectric constant of the sample in the CPI expression obtained on the basis of the Lifshitz theory by the static DRF obtained using the expressions for the polarization function we started with. Though the approach replaces a macroscopic constant by a microscopic
Milton, Kimball A.; Fulling, Stephen A.; Parashar, Prachi; Kalauni, Pushpa; Murphy, Taylor
2016-04-01
Motivated by a desire to understand quantum fluctuation energy densities and stress within a spatially varying dielectric medium, we examine the vacuum expectation value for the stress tensor of a scalar field with arbitrary conformal parameter, in the background of a given potential that depends on only one spatial coordinate. We regulate the expressions by incorporating a temporal-spatial cutoff in the (imaginary) time and transverse-spatial directions. The divergences are captured by the zeroth- and second-order WKB approximations. Then the stress tensor is "renormalized" by omitting the terms that depend on the cutoff. The ambiguities that inevitably arise in this procedure are both duly noted and restricted by imposing certain physical conditions; one result is that the renormalized stress tensor exhibits the expected trace anomaly. The renormalized stress tensor exhibits no pressure anomaly, in that the principle of virtual work is satisfied for motions in a transverse direction. We then consider a potential that defines a wall, a one-dimensional potential that vanishes for z 0 , for z >0 . Previously, the stress tensor had been computed outside of the wall, whereas now we compute all components of the stress tensor in the interior of the wall. The full finite stress tensor is computed numerically for the two cases where explicit solutions to the differential equation are available, α =1 and 2. The energy density exhibits an inverse linear divergence as the boundary is approached from the inside for a linear potential, and a logarithmic divergence for a quadratic potential. Finally, the interaction between two such walls is computed, and it is shown that the attractive Casimir pressure between the two walls also satisfies the principle of virtual work (i.e., the pressure equals the negative derivative of the energy with respect to the distance between the walls).
The Poisson algebra of the invariant charges of the Nambu-Goto theory: Casimir elements
International Nuclear Information System (INIS)
Pohlmeyer, K.
1988-01-01
The reparametrization invariant ''non-local'' conserved charges of the Nambu-Goto theory form an algebra under Poisson bracket operation. The center of the formal closure of this algebra is determined. The relation of the central elements to the constraints of the Nambu-Goto theory is clarified. (orig.)
Enhanced symmetries of gauge theory and resolving the spectrum of local operators
International Nuclear Information System (INIS)
Kimura, Yusuke; Ramgoolam, Sanjaye
2008-01-01
Enhanced global non-Abelian symmetries at zero coupling in Yang Mills theory play an important role in diagonalizing the two-point functions of multimatrix operators. Generalized Casimirs constructed from the iterated commutator action of these enhanced symmetries resolve all the multiplicity labels of the bases of matrix operators which diagonalize the two-point function. For the case of U(N) gauge theory with a single complex matrix in the adjoint of the gauge group we have a U(N) x4 global symmetry of the scaling operator at zero coupling. Different choices of commuting sets of Casimirs, for the case of a complex matrix, lead to the restricted Schur basis previously studied in connection with string excitations of giant gravitons and the Brauer basis studied in connection with brane-antibrane systems. More generally these remarks can be extended to the diagonalization for any global symmetry group G. Schur-Weyl duality plays a central role in connecting the enhanced symmetries and the diagonal bases.
Hertzberg, Jared B; Aksit, Mahmut; Otelaja, Obafemi O; Stewart, Derek A; Robinson, Richard D
2014-02-12
Thermal transport in nanostructures is strongly affected by phonon-surface interactions, which are expected to depend on the phonon's wavelength and the surface roughness. Here we fabricate silicon nanosheets, measure their surface roughness (∼ 1 nm) using atomic force microscopy (AFM), and assess the phonon scattering rate in the sheets with a novel technique: a microscale phonon spectrometer. The spectrometer employs superconducting tunnel junctions (STJs) to produce and detect controllable nonthermal distributions of phonons from ∼ 90 to ∼ 870 GHz. This technique offers spectral resolution nearly 10 times better than a thermal conductance measurement. We compare measured phonon transmission rates to rates predicted by a Monte Carlo model of phonon trajectories, assuming that these trajectories are dominated by phonon-surface interactions and using the Ziman theory to predict phonon-surface scattering rates based on surface topology. Whereas theory predicts a diffuse surface scattering probability of less than 40%, our measurements are consistent with a 100% probability. Our nanosheets therefore exhibit the so-called "Casimir limit" at a much lower frequency than expected if the phonon scattering rates follow the Ziman theory for a 1 nm surface roughness. Such a result holds implications for thermal management in nanoscale electronics and the design of nanostructured thermoelectrics.
Chen, Shao-Guang
According to f =d(mv)/dt=m(dv/dt)+ v(dm/dt), a same gravitational formula had been de-duced from the variance in physical mass of QFT and from the variance in mass of inductive energy-transfer of GR respectively: f QF T = f GR = -G (mM/r2 )((r/r)+(v/c)) when their interaction-constants are all taken the experimental values (H05-0029-08, E15-0039-08). f QF T is the quasi-Casimir pressure. f GR is equivalent to Einstein's equation, then more easy to solve it. The hypothesis of the equivalent principle is not used in f QF T , but required by f GR . The predictions of f QF T and f GR are identical except that f QF T has quantum effects but f GR has not and f GR has Lense-Thirring effect but f QF T has not. The quantum effects of gravitation had been verified by Nesvizhevsky et al with the ultracold neutrons falling in the earth's gravitational field in 2002. Yet Lense-Thirring effect had not been measured by GP-B. It shows that f QF T is essential but f GR is phenomenological. The macro-f QF T is the statistic average pressure collided by net virtual neutrinos ν 0 flux (after self-offset in opposite directions) and in direct proportion to the mass. But micro-f QF T is in direct proportion to the scattering section. The electric mass (in inverse proportion to de Broglie wavelength λ) far less than nucleonic mass and the electric scattering section (in direct proportion to λ2 ) far large than that of nucleon, then the net ν 0 flux pressure exerted to electron far large than that to nucleon and the electric displacement far large than that of nucleon, it causes the gravitational polarization of positive-negative charge center separation. Because the gravity far less than the electromagnetic binding force, in atoms the gravitational polarization only produces a little separation. But the net ν 0 flux can press a part freedom electrons in plasma of ionosphere into the earth's surface, the static electric force of redundant positive ions prevents electrons from further
Valchev, Galin; Dantchev, Daniel
2017-08-01
We study systems in which both long-ranged van der Waals and critical Casimir interactions are present. The latter arise as an effective force between bodies when immersed in a near-critical medium, say a nonpolar one-component fluid or a binary liquid mixture. They are due to the fact that the presence of the bodies modifies the order parameter profile of the medium between them as well as the spectrum of its allowed fluctuations. We study the interplay between these forces, as well as the total force (TF) between a spherical colloid particle and a thick planar slab and between two spherical colloid particles. We do that using general scaling arguments and mean-field-type calculations utilizing the Derjaguin and the surface integration approaches. They both are based on data of the forces between two parallel slabs separated at a distance L from each other, confining the fluctuating fluid medium characterized by its temperature T and chemical potential μ. The surfaces of the colloid particles and the slab are coated by thin layers exerting strong preference to the liquid phase of the fluid, or one of the components of the mixture, modeled by strong adsorbing local surface potentials, ensuring the so-called (+,+) boundary conditions. On the other hand, the core region of the slab and the particles influence the fluid by long-ranged competing dispersion potentials. We demonstrate that for a suitable set of colloids-fluid, slab-fluid, and fluid-fluid coupling parameters, the competition between the effects due to the coatings and the core regions of the objects involved result, when one changes T, μ, or L, in sign change of the Casimir force (CF) and the TF acting between the colloid and the slab, as well as between the colloids. This can be used for governing the behavior of objects, say colloidal particles, at small distances, say in colloid suspensions for preventing flocculation. It can also provide a strategy for solving problems with handling, feeding
Valchev, Galin; Dantchev, Daniel
2017-08-01
We study systems in which both long-ranged van der Waals and critical Casimir interactions are present. The latter arise as an effective force between bodies when immersed in a near-critical medium, say a nonpolar one-component fluid or a binary liquid mixture. They are due to the fact that the presence of the bodies modifies the order parameter profile of the medium between them as well as the spectrum of its allowed fluctuations. We study the interplay between these forces, as well as the total force (TF) between a spherical colloid particle and a thick planar slab and between two spherical colloid particles. We do that using general scaling arguments and mean-field-type calculations utilizing the Derjaguin and the surface integration approaches. They both are based on data of the forces between two parallel slabs separated at a distance L from each other, confining the fluctuating fluid medium characterized by its temperature T and chemical potential μ . The surfaces of the colloid particles and the slab are coated by thin layers exerting strong preference to the liquid phase of the fluid, or one of the components of the mixture, modeled by strong adsorbing local surface potentials, ensuring the so-called (+,+) boundary conditions. On the other hand, the core region of the slab and the particles influence the fluid by long-ranged competing dispersion potentials. We demonstrate that for a suitable set of colloids-fluid, slab-fluid, and fluid-fluid coupling parameters, the competition between the effects due to the coatings and the core regions of the objects involved result, when one changes T , μ , or L , in sign change of the Casimir force (CF) and the TF acting between the colloid and the slab, as well as between the colloids. This can be used for governing the behavior of objects, say colloidal particles, at small distances, say in colloid suspensions for preventing flocculation. It can also provide a strategy for solving problems with handling, feeding
Operator properties of generalized coherent state systems
Indian Academy of Sciences (India)
In some cases, but not necessarily always, the overcompleteness leads to entire functions and characteristic sets playing a special .... To reach the Perelomov form we identify the Lie group as the Heisenberg–Weyl group. (H–W group) with Х and Ф as .... The quadratic Casimir invariant is. Pramana – J. Phys., Vol. 56, Nos 2 ...
Dostal, Jiri
1993-01-01
This book provides the reader with the practical knowledge necessary to select and use operational amplifier devices. It presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits.Provides the reader with practical knowledge necessary to select and use operational amplifier devices. Presents an extensive treatment of applications and a practically oriented, unified theory of operational circuits
Directory of Open Access Journals (Sweden)
Anda VELICANU
2010-09-01
Full Text Available This paper contains a brief description of the most important operations that can be performed on spatial data such as spatial queries, create, update, insert, delete operations, conversions, operations on the map or analysis on grid cells. Each operation has a graphical example and some of them have code examples in Oracle and PostgreSQL.
Directory of Open Access Journals (Sweden)
Ram U. Verma
2000-01-01
Full Text Available We present the solvability of a class of nonlinear variational inequalities involving pseudomonotone operators in a locally convex Hausdorff topological vector spaces setting. The obtained result generalizes similar variational inequality problems on monotone operators.
Tsichritzis, Dionysios C; Rheinboldt, Werner
1974-01-01
Operating Systems deals with the fundamental concepts and principles that govern the behavior of operating systems. Many issues regarding the structure of operating systems, including the problems of managing processes, processors, and memory, are examined. Various aspects of operating systems are also discussed, from input-output and files to security, protection, reliability, design methods, performance evaluation, and implementation methods.Comprised of 10 chapters, this volume begins with an overview of what constitutes an operating system, followed by a discussion on the definition and pr
Boehme, Thomas K
1987-01-01
Operational Calculus, Volume II is a methodical presentation of operational calculus. An outline of the general theory of linear differential equations with constant coefficients is presented. Integral operational calculus and advanced topics in operational calculus, including locally integrable functions and convergence in the space of operators, are also discussed. Formulas and tables are included.Comprised of four sections, this volume begins with a discussion on the general theory of linear differential equations with constant coefficients, focusing on such topics as homogeneous and non-ho
Keyl, M.; Kiukas, J.; Werner, R. F.
2016-05-01
In this paper, we introduce Schwartz operators as a non-commutative analog of Schwartz functions and provide a detailed discussion of their properties. We equip them, in particular, with a number of different (but equivalent) families of seminorms which turns the space of Schwartz operators into a Fréchet space. The study of the topological dual leads to non-commutative tempered distributions which are discussed in detail as well. We show, in particular, that the latter can be identified with a certain class of quadratic forms, therefore making operations like products with bounded (and also some unbounded) operators and quantum harmonic analysis available to objects which are otherwise too singular for being a Hilbert space operator. Finally, we show how the new methods can be applied by studying operator moment problems and convergence properties of fluctuation operators.
Sellmaier, Florian; Schmidhuber, Michael
2015-01-01
The book describes the basic concepts of spaceflight operations, for both, human and unmanned missions. The basic subsystems of a space vehicle are explained in dedicated chapters, the relationship of spacecraft design and the very unique space environment are laid out. Flight dynamics are taught as well as ground segment requirements. Mission operations are divided into preparation including management aspects, execution and planning. Deep space missions and space robotic operations are included as special cases. The book is based on a course held at the German Space Operation Center (GSOC).
International Nuclear Information System (INIS)
Anon.
1979-01-01
Operations of the SuperHILAC, the Bevatron/Bevalac, and the 184-inch Synchrocyclotron during the period from October 1977 to September 1978 are discussed. These include ion source development, accelerator facilities, the Heavy Ion Spectrometer System, and Bevelac biomedical operations
DEFF Research Database (Denmark)
Nielsen, Thomas Rosendal; Hustvedt, Kjersti
2017-01-01
by Bakhtinian theory, Brian Edmiston developed a solution to this in the 1990s: the principle of ‘dialogic sequencing’. Aiming to escape the conflict between relativism and absolutism, we present an alternative to Edmiston’s approach, based on Niklas Luhmann’s theory of ‘operational closure’: operational...
Indian Academy of Sciences (India)
M Suresh Babu is currently a fourth year undergraduate student in the Department of. Computer Science and. Engineering, Narayana. Engineering College,. Nellore, Andhra Pradesh. He would like to work in operating systems, computer networks and also in Internet security concepts. Keywords. Operating systems, file sys-.
2014-10-16
the so-called Threat Image Pro 51 April 2014 Operational Stress on Internet and eCommerce THE WALL STREET JOURNAL. TECH TECHNOLOGY Massive OpenSSL...8217!;:;a.L~ and · ...... -n ... ,.,. ... ,. 53 September 24, 2014 Operational Stress on Internet and eCommerce ::;:\\\\ t?nQCldQt?~ . REVIEWS
Tetsuya, Saito; Nauta, Bram
2008-01-01
To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a differential amplifier circuit 1;
Tetsuya, Saito; Nauta, Bram
2011-01-01
PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. SOLUTION: The operation amplifier comprises: a
Tetsuya, S.; Nauta, Bram
2007-01-01
PROBLEM TO BE SOLVED: To provide an operation amplifier which improves power source voltage removal ratios while assuring phase compensation characteristics, and therefore can be realized with a small-scale circuit and low power consumption. ; SOLUTION: The operation amplifier comprises: a
Energy Technology Data Exchange (ETDEWEB)
Lee, Ji Bok; Jeon, Byung Jin; Kwack, Byung Ho [and others
1997-01-01
HANARO was configurated its first operating core in 1995. Long term operation test was conducted up to 3-1 cycle during 1996, in order to investigate the reactor characteristics due to fuel depletion and additional fuel loading. Now HANARO has accumulated 168.4 days of total operation time and 2,687.5 MWD of total thermal output. Reactor analysis, producing operation datum and its validation with test, periodic inspection and maintenance of the facility are continuously conducted for safe operation of the HANARO. Conducted the verification tests for installed utilization facilities, and successfully performed the radiation emergency drill. The shutdown report of TRIGA Mark II and III was submitted to MOST, and decommissioning will be started from 1997. (author). 70 tabs., 50 figs., 27 refs.
International Nuclear Information System (INIS)
Bender, C.M.
1984-01-01
The finite-element method enables us to convert the operator differential equations of a quantum field theory into operator difference equations. These difference equations are consistent with the requirements of quantum mechanics and they do not exhibit fermion doubling, a problem that frequently plagues lattice treatments of fermions. Guage invariance can also be incorporated into the difference equations. On a finite lattice the operator difference equations can be solved in closed form. For the case of the Schwinger model the anomaly is computed and results in excellent agreement are obtained with the known continuum value
Shaw, J
2013-01-01
Reactor Operation covers the theoretical aspects and design information of nuclear reactors. This book is composed of nine chapters that also consider their control, calibration, and experimentation.The opening chapters present the general problems of reactor operation and the principles of reactor control and operation. The succeeding chapters deal with the instrumentation, start-up, pre-commissioning, and physical experiments of nuclear reactors. The remaining chapters are devoted to the control rod calibrations and temperature coefficient measurements in the reactor. These chapters also exp
Almeida, João; Oliveira, José; Pinto, Alberto
2018-01-01
This proceedings book presents selected contributions from the XVIII Congress of APDIO (the Portuguese Association of Operational Research) held in Valença on June 28–30, 2017. Prepared by leading Portuguese and international researchers in the field of operations research, it covers a wide range of complex real-world applications of operations research methods using recent theoretical techniques, in order to narrow the gap between academic research and practical applications. Of particular interest are the applications of, nonlinear and mixed-integer programming, data envelopment analysis, clustering techniques, hybrid heuristics, supply chain management, and lot sizing and job scheduling problems. In most chapters, the problems, methods and methodologies described are complemented by supporting figures, tables and algorithms. The XVIII Congress of APDIO marked the 18th installment of the regular biannual meetings of APDIO – the Portuguese Association of Operational Research. The meetings bring toget...
International Nuclear Information System (INIS)
Wirstad, J.
1983-12-01
The traditional operator job is changing, which among other things has generated a need for better job training. Surprisingly increased process automation has lead to increased operator qualifications, i.e. basic job training but also up-date and rehearsal training within certain fixed intervals. There are several, similar models for instructional system development available in the literature. One model which is of special interest integrates Operator Training development and Man-Machine Interfaces development. The extent to which Systematic Operator Training has been implemented varies with branches and companies. The nuclear power branch is given as an example in the report. This branch probably represents something better than the average among the process industries.(author)
National Research Council Canada - National Science Library
Proks, Josef
2000-01-01
Peace operations are more and more important in the contemporary world. The end of the Cold War increased not only possibilities of solving disputes by the international community but also by the number and diversity of threats and issues...
2015-01-01
A one-sentence definition of operator theory could be: The study of (linear) continuous operations between topological vector spaces, these being in general (but not exclusively) Fréchet, Banach, or Hilbert spaces (or their duals). Operator theory is thus a very wide field, with numerous facets, both applied and theoretical. There are deep connections with complex analysis, functional analysis, mathematical physics, and electrical engineering, to name a few. Fascinating new applications and directions regularly appear, such as operator spaces, free probability, and applications to Clifford analysis. In our choice of the sections, we tried to reflect this diversity. This is a dynamic ongoing project, and more sections are planned, to complete the picture. We hope you enjoy the reading, and profit from this endeavor.
Applied Operations Research: Operator's Assistant
Cole, Stuart K.
2015-01-01
NASA operates high value critical equipment (HVCE) that requires trouble shooting, periodic maintenance and continued monitoring by Operations staff. The complexity HVCE and information required to maintain and trouble shoot HVCE to assure continued mission success as paper is voluminous. Training on new HVCE is commensurate with the need for equipment maintenance. LaRC Research Directorate has undertaken a proactive research to support Operations staff by initiation of the development and prototyping an electronic computer based portable maintenance aid (Operator's Assistant). This research established a goal with multiple objectives and a working prototype was developed. The research identified affordable solutions; constraints; demonstrated use of commercial off the shelf software; use of the US Coast Guard maintenance solution; NASA Procedure Representation Language; and the identification of computer system strategies; where these demonstrations and capabilities support the Operator, and maintenance. The results revealed validation against measures of effectiveness and overall proved a substantial training and capability sustainment tool. The research indicated that the OA could be deployed operationally at the LaRC Compressor Station with an expectation of satisfactorily results and to obtain additional lessons learned prior to deployment at other LaRC Research Directorate Facilities. The research revealed projected cost and time savings.
International Nuclear Information System (INIS)
McRae, L.P.; Six, D.E.
1991-01-01
In 1987, Westinghouse Hanford Company began operating a first-generation integrated safeguards system in the Plutonium Finishing Plant storage vaults. This Vault Safety and Inventory System is designed to integrate data into a computer-based nuclear material inventory monitoring system. The system gathers, in real time, measured physical parameters that generate nuclear material inventory status data for thousands of stored items and sends tailored report to the appropriate users. These data include canister temperature an bulge data reported to Plant Operations and Material Control and Accountability personnel, item presence and identification data reported to Material Control and Accountability personnel, and unauthorized item movement data reported to Security response forces and Material Control and Accountability personnel. The Westinghouse Hanford Company's experience and operational benefits in using this system for reduce radiation exposure, increase protection against insider threat, and real-time inventory control are discussed in this paper
International Nuclear Information System (INIS)
Natalizio, A.; Anderson, J.W.D.; Sills, H.E.
1988-01-01
Abundant, cheap computing power has provided industry with a far greater opportunity than was available one or two decades ago to automate industrial processes and to improve the man-machine interface. Exciting innovations in knowledge representation methods arising from artificial intelligence research pave the way for advanced support systems for assisting plant operators. AECL has recognized the importance of knowledge based system technology, particularly expert systems, in the achievement of this objective and also, as a strategic technology to be fully exploited in the next generation of CANDU reactors. Operator Companion, an expert system intended to diagnose plant faults and advise the operator on appropriate restoring or corrective actions, is a major undertaking which is receiving support within the research and engineering groups of AECL
International Nuclear Information System (INIS)
2010-01-01
The chapter presents the operational indicators related to budget, travel costs and tickets, the evolution of the annual program for regulatory inspection, the scientific production, requested patents and the numbers related to the production of the services offered by the Institution
Indian Academy of Sciences (India)
areas in which this type is useful are multimedia, virtual reality, and advanced scientific projects such as undersea exploration and planetary rovers. Because of the expanded uses for soft real-time functionality, it is finding its way into most current operating systems, including major versions of Unix and Windows NT OS.
National Research Council Canada - National Science Library
Lewis, William
1995-01-01
.... Indeed, despite the energetic leadership of Under Secretary-General Kofi R. Annan who directs the Department of Peacekeeping Operations, the organization has increasing difficulty in acquiring properly trained and equipped forces in time to intervene in conflict situations and humanitarian crises.
International Nuclear Information System (INIS)
Anon.
1980-01-01
This section is concerned with the operation of both the tandem-linac system and the Dynamitron, two accelerators that are used for entirely different research. Developmental activities associated with the tandem and the Dynamitron are also treated here, but developmental activities associated with the superconducting linac are covered separately because this work is a program of technology development in its own right
DEFF Research Database (Denmark)
Stüben, Henning; Tietjen, Anne
2006-01-01
Abstract: This paper seeks to challenge the notion of context from an operational perspective. Can we grasp the forces that shape the complex conditions for an architectural or urban design within the notion of context? By shifting the gaze towards the agency of architecture, contextual analysis...
Indian Academy of Sciences (India)
The process concept and concurrency are at the heart of modern operating systems (OS). A process is the unit of work in a computer system. A process must be in main memory during execution. To improve the utilization of central processing unit. (CPU) as well as the speed of its response to its users, the computer must ...
2003-01-01
Operational Circular N° 4 - April 2003 Conditions for use by members of the CERN personnel of vehicles belonging to or rented by CERN - This circular has been drawn up. Operational Circular N° 5 - October 2000 Use of CERN computing facilities - Further details on the personal use of CERN computing facilities Operational Circular N° 5 and its Subsidiary Rules http://cern.ch/ComputingRules defines the rules for the use of CERN computing facilities. One of the basic principles governing such use is that it must come within the professional duties of the user concerned, as defined by the user's divisional hierarchy. However, personal use of the computing facilities is tolerated or allowed provided : a) It is in compliance with Operational Circular N° 5 and not detrimental to official duties, including those of other users; b) the frequency and duration is limited and there is a negligible use of CERN resources; c) it does not constitute a political, commercial and/or profit-making activity; d) it is not...
Your Lung Operation: After Your Operation
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International Nuclear Information System (INIS)
Launeau, F.
2016-01-01
The CIGEO facility dedicated to the geological disposal of high- and intermediate-level radioactive wastes will be composed of 2 parts: an underground facility at a depth of 500 m to dispose the waste packages in tunnels and a surface facility to take delivery of the wastes and prepare the packages. The underground facility will be built progressively and will cover a surface of 15 km 2 at the end of Cigeo operating-life. A large part of the surface facility (located a few km away from the waste reception place) will be dedicated to the works led deep underground to build the tunnels and will receive drilling cuttings. The article describes also the ramp and carts to lead waste packages underground. Most of the operations will be automated. The definitive closure of the tunnels will be made with swelling clay and concrete plugs. (A.C.)
DEFF Research Database (Denmark)
Wistoft, Karen; Højlund, Holger
2012-01-01
educational approaches. Methods: Mixed qualitative design: survey based on telephone interviews with health managers (n=72), personal and focus group interviews with health professionals (n=84) and pupils (n=108) from 18 school classes, and comparative case studies in five selected municipalities of various...... educational goals, learning content, or value clarification. Health pedagogy is often a matter of retrospective rationalization rather than the starting point of planning. Health and risk behaviour approaches override health educational approaches. Conclusions: Operational links between health education...
International Nuclear Information System (INIS)
Pruvost, N.; Tsitouras, J.
1981-01-01
The objectives of Operation Poorman were to design and build a portable seismic system and to set up and use this system in a cold-weather environment. The equipment design uses current technology to achieve a low-power, lightweight system that is configured into three modules. The system was deployed in Alaska during wintertime, and the results provide a basis for specifying a mission-ready seismic verification system
Critical Casimir forces and anomalous wetting
Indian Academy of Sciences (India)
the origin of artefacts in the profiles found by Ueno et al, whose fringe patterns were severely bent, due to inhomogeneous stresses on the two cell windows. In our new experiment, we have found zero contact angle in the whole temperature range. Two examples of profiles are shown in figure 8. At low temperature (271 mK).
2190-IJBCS-Article-Casimir Anouma
African Journals Online (AJOL)
hp
breadmaking were assessed by sensory analysis of products obtained. Both roots and fermented flours were energizing foods. Moisture (6.09-10.49%), protein (1.12-1.57%), ash ... Keywords: Gelatinized food, yace cultivar, sensory evaluation, composite flour, bread. ...... parameters that guide consumer choice.
Critical Casimir forces and anomalous wetting
Indian Academy of Sciences (India)
range forces responsible for this exception. By using .... using an ϵ-expansion method. For periodic boundary conditions and ..... interface profile is obtained by subtracting the optical path without the interface from the optical path with the interface ...
1092-IJBCS-Article-Casimir Anouma KOKO
African Journals Online (AJOL)
KODJIO NORBERT
product was ground and sieved with a 200 µm mesh sieve. Proximate composition and the ability of fermented flour to be processed into placali appreciated by consumers were evaluated. Moisture, protein, ash, fat, total sugars and cyanide contents were low while starch, total carbohydrate and energy contents were high.
The mathematics of the Casimir effect
International Nuclear Information System (INIS)
Dowling, J.P.
1987-02-01
We show how a famous problem in theoretical physics leads to two classical formulas which allow one to compute the difference between a definite integral and an infinite sum of the same functional form f. (author). 5 refs, 3 figs
Casimir effect in the rainbow Einstein's universe
Bezerra, V. B.; Mota, H. F.; Muniz, C. R.
2017-10-01
In the present paper we investigate the effects caused by the modification of the dispersion relation obtained by solving the Klein-Gordon equation in the closed Einstein's universe in the context of rainbow's gravity models. Thus, we analyse how the quantum vacuum fluctuations of the scalar field are modified when compared with the results obtained in the usual General Relativity scenario. The regularization, and consequently the renormalization, of the vacuum energy is performed adopting the Epstein-Hurwitz and Riemann's zeta functions.
DEFF Research Database (Denmark)
Wistoft, Karen
2010-01-01
and have been the object of great expectations concerning the ability to incorporate health concerns into every welfare area through health promotion strategies. The paper draws on results and analyses of a collective research project funded by the Danish National Research Council and carried out...... as networks: second, a semantic perspective on discourses and concepts of health, and, third, a health pedagogical perspective on participation, intervention, and roles. This paper argues for the importance of 'operative links' between different levels in health strategies. It is proposed that such links...
International Nuclear Information System (INIS)
Knuefer; Lindauer
1980-01-01
Besides that at spectacular events a combination of component failure and human error is often found. Especially the Rasmussen-Report and the German Risk Assessment Study show for pressurised water reactors that human error must not be underestimated. Although operator errors as a form of human error can never be eliminated entirely, they can be minimized and their effects kept within acceptable limits if a thorough training of personnel is combined with an adequate design of the plant against accidents. Contrary to the investigation of engineering errors, the investigation of human errors has so far been carried out with relatively small budgets. Intensified investigations in this field appear to be a worthwhile effort. (orig.)
Operator theory, operator algebras and applications
Lebre, Amarino; Samko, Stefan; Spitkovsky, Ilya
2014-01-01
This book consists of research papers that cover the scientific areas of the International Workshop on Operator Theory, Operator Algebras and Applications, held in Lisbon in September 2012. The volume particularly focuses on (i) operator theory and harmonic analysis (singular integral operators with shifts; pseudodifferential operators, factorization of almost periodic matrix functions; inequalities; Cauchy type integrals; maximal and singular operators on generalized Orlicz-Morrey spaces; the Riesz potential operator; modification of Hadamard fractional integro-differentiation), (ii) operator algebras (invertibility in groupoid C*-algebras; inner endomorphisms of some semi group, crossed products; C*-algebras generated by mappings which have finite orbits; Folner sequences in operator algebras; arithmetic aspect of C*_r SL(2); C*-algebras of singular integral operators; algebras of operator sequences) and (iii) mathematical physics (operator approach to diffraction from polygonal-conical screens; Poisson geo...
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
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A Survey on Operator Monotonicity, Operator Convexity, and Operator Means
Directory of Open Access Journals (Sweden)
Pattrawut Chansangiam
2015-01-01
Full Text Available This paper is an expository devoted to an important class of real-valued functions introduced by Löwner, namely, operator monotone functions. This concept is closely related to operator convex/concave functions. Various characterizations for such functions are given from the viewpoint of differential analysis in terms of matrix of divided differences. From the viewpoint of operator inequalities, various characterizations and the relationship between operator monotonicity and operator convexity are given by Hansen and Pedersen. In the viewpoint of measure theory, operator monotone functions on the nonnegative reals admit meaningful integral representations with respect to Borel measures on the unit interval. Furthermore, Kubo-Ando theory asserts the correspondence between operator monotone functions and operator means.
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Participate Resources Webinars for Young Surgeons YFA E-News Resident and Associate Society Resident and Associate Society ... Leader International Exchange Scholar Program Resources RAS E-News Medical Students Operation Giving Back Operation Giving Back ...
Your Lung Operation: After Your Operation
Full Text Available ... to Participate Resources Webinars for Young Surgeons YFA E-News Resident and Associate Society Resident and Associate ... ACS Leader International Exchange Scholar Program Resources RAS E-News Medical Students Operation Giving Back Operation Giving ...
Space station operations management
Cannon, Kathleen V.
1989-01-01
Space Station Freedom operations management concepts must be responsive to the unique challenges presented by the permanently manned international laboratory. Space Station Freedom will be assembled over a three year period where the operational environment will change as significant capability plateaus are reached. First Element Launch, Man-Tended Capability, and Permanent Manned Capability, represent milestones in operational capability that is increasing toward mature operations capability. Operations management concepts are being developed to accomodate the varying operational capabilities during assembly, as well as the mature operational environment. This paper describes operations management concepts designed to accomodate the uniqueness of Space Station Freedoom, utilizing tools and processes that seek to control operations costs.
International Nuclear Information System (INIS)
Liu Rong; Yang Shuchun; Peng Jun; Zhou Shoukang
2003-01-01
Experiences and work methods with High Flux Engineering Test Reactor (HFETR) operation are introduced, which have been accumulated in a long period of operation, in the aspects as reactor operation, test, maintenance, operator training and incident management. It's clear that the safety operation of HFETR has been ensured, and the methods are valid. (authors)
Heat transfer operators associated with quantum operations
International Nuclear Information System (INIS)
Aksak, C; Turgut, S
2011-01-01
Any quantum operation applied on a physical system is performed as a unitary transformation on a larger extended system. If the extension used is a heat bath in thermal equilibrium, the concomitant change in the state of the bath necessarily implies a heat exchange with it. The dependence of the average heat transferred to the bath on the initial state of the system can then be found from the expectation value of a Hermitian operator, which is named as the heat transfer operator (HTO). The purpose of this paper is to investigate the relation between the HTOs and the associated quantum operations. Since any given quantum operation on a system can be realized by different baths and unitaries, many different HTOs are possible for each quantum operation. On the other hand, there are also strong restrictions on the HTOs which arise from the unitarity of the transformations. The most important of these is the Landauer erasure principle. This paper is concerned with the question of finding a complete set of restrictions on the HTOs that are associated with a given quantum operation. An answer to this question has been found only for a subset of quantum operations. For erasure operations, these characterizations are equivalent to the generalized Landauer erasure principle. For the case of generic quantum operations, however, it appears that the HTOs obey further restrictions which cannot be obtained from the entropic restrictions of the generalized Landauer erasure principle.
Directory of Open Access Journals (Sweden)
Miguel Conde Pazos
2012-03-01
Full Text Available Throughout the seventeenth century, the Vasa of Poland and the Habsburg family established a series of contacts which would link to the Catholic Monarchy with the events in Eastern Europe. This article addresses a specific event of these relationships: the closure by the French of Prince Casimir on his way to Spain, and subse-quent negotiations between his half-brother, King Ladislaus IV, and the viceroy of Naples, the Duke of Medina de las Torres, to raise an army of punishment to free the prince. In this negotiation between Naples, Madrid, Vienna and Warsaw, the catholic king diplomacy interacted with leading personalities of the Polish court.Durante todo el siglo XVII los Vasa de Polonia y la familia Habsburgo establecieron una serie de contactos que vincularían a la Monarquía Católica con los acontecimientos de la Europa Oriental. El presente artículo trata un suceso concreto de estas relaciones: el encierro por parte de los franceses del príncipe Casimiro cuando se dirigía hacia España, y las ulteriores negociaciones entre su medio hermano, el rey Ladislao IV, y el virrey de Nápoles, el duque de Medina de las Torres, para levantar un ejército de castigo que liberara al príncipe. En esta negociación entre Nápoles, Madrid, Viena y Varsovia, la diplomacia del rey Católico interactuó con los más destacados personajes de la corte polaca.
1985-01-01
A nationwide survey of transit operators indicated that absenteeism among transit operators is a significant problem and that the associated costs are substantial. The objective of the research reported here was to determine the scope of operator abs...
A complete analogue of Hardy's theorem on SL2 (R) and ...
Indian Academy of Sciences (India)
We also consider the `heat equation' of the Casimir operator, which plays the role of the Laplacian for the group. We show that despite the structural difference of the Casimir with the Laplacian on R n or the Laplace-Beltrami operator on the Riemannian symmetric spaces, it is possible to have a heat kernel. This heat kernel ...
Conduct of operations: establishing operational focus and setting operational standards
International Nuclear Information System (INIS)
Lane, L.; McGuigan, K.
1998-01-01
Due to the nature of our business, we have often tended to focus on the technological aspects of the nuclear industry. The focus of this paper is directed towards the importance of addressing the people skills, attitudes, and 'culture' within, and surrounding, our facilities as key areas of improvement. Within Ontario Hydro Nuclear (OLIN) we have developed the terminology 'event free' operation and 'event free' culture. 'Event Free' recognizes errors as a part of human performance. 'Event Free' takes into account human weaknesses, and provides tools (such as standards) to manage, control, and mitigate errors. In essence, 'Event Free' encompasses two concepts: 1. Prevent errors from occurring; 2. If an error is made, catch it before it can affect safe operation of the facility, learn from the error, and ensure that it does not happen again. In addressing these business realities, Ontario Hydro has identified a number of key support mechanisms and corresponding performance standards that are essential for achieving operating excellence and an 'event free' business culture. This paper will discuss two operational aspects of an 'event free' culture, the first being a set of expectations to enhance the culture, and the second an example of cultural change: 1. Operating Standards - establishing clear expectations for human performance in operating staff; 2. Operational Focus - the understanding that, as a nuclear worker, you should consider every task, activity, in fact everything you do in this business, for the potential to affect safe and reliable operation of a nuclear facility. Note that although the term 'Operational' appears in the title, this concept applies to every individual in the nuclear business, from the cleaner, to the Board of Directors, to the external supplier. (author)
DEFF Research Database (Denmark)
Welch, Lawrence S.; Benito, Gabriel R. G.; Petersen, Bent
Introduction and theory -- Introduction -- Theoretical approaches -- Modes of operation -- Franchising -- Licensing -- Management contracts -- International subcontracting -- Project operations -- Exports -- Alliances -- Foreign direct investment -- Strategies -- Mode switching and stretching...
National Aeronautics and Space Administration — The AES Autonomous Mission Operations project will develop understanding of the impacts of increasing communication time delays on mission operations and develop...
Saxton Transportation Operations Laboratory
Federal Laboratory Consortium — The Saxton Transportation Operations Laboratory (Saxton Laboratory) is a state-of-the-art facility for conducting transportation operations research. The laboratory...
Orbits of operators and operator semigroups
Czech Academy of Sciences Publication Activity Database
Müller, Vladimír
-, č. 1737 (2011), s. 78-90 ISSN 1880-2818. [Noncommutative structure in operator theory and its application. Kyoto, 27.10.2010-29.10.2010] R&D Projects: GA ČR GA201/09/0473; GA AV ČR IAA100190903 Institutional research plan: CEZ:AV0Z10190503 Keywords : orbits of operators * hypercyclicity * semigroups of operators Subject RIV: BA - General Mathematics
Your Lung Operation: After Your Operation
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Separable quadratic stochastic operators
International Nuclear Information System (INIS)
Rozikov, U.A.; Nazir, S.
2009-04-01
We consider quadratic stochastic operators, which are separable as a product of two linear operators. Depending on properties of these linear operators we classify the set of the separable quadratic stochastic operators: first class of constant operators, second class of linear and third class of nonlinear (separable) quadratic stochastic operators. Since the properties of operators from the first and second classes are well known, we mainly study the properties of the operators of the third class. We describe some Lyapunov functions of the operators and apply them to study ω-limit sets of the trajectories generated by the operators. We also compare our results with known results of the theory of quadratic operators and give some open problems. (author)
Jung, Il Bong; Lim, Pil Sang; Park, Sang Soo
2005-04-01
We construct examples which distinguish clearly the classes of p-hyponormal operators for 0normaloid operators on the complex Hilbert space. Only a few examples of p-hyponormal operators have been examined. Our technique can provide many examples related to the above operators.
International Nuclear Information System (INIS)
Sonoda, Hidenori
1992-01-01
We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e. the strong fine structure constant and the quark mass) of QCD in four- dimensional euclidean space. The formula is given as spatial integration of the operator conjugate to a parameter. The operator product of a composite operator and a conjugate operator has an unintegrable part, and the formula requires divergent subtractions. By imposing consistency conditions we drive a relation between the anomalous dimensions of the composite operators and the unintegrable part of the operator product coefficients. (orig.)
International Nuclear Information System (INIS)
Lupton, L.R.; Anderson, L.L.; Basso, R.A.J.
1989-11-01
As CANDU plants become more complex, and are operated under tighter constraints and for longer periods between outages, plant operations staff will have to absorb more information to correctly and rapidly respond to upsets. A development program is underway at AECL to use expert systems and interactive media tools to assist operations staff of existing and future CANDU plants. The complete system for plant information access and display, on-line advice and diagnosis, and interactive operating procedures is called the Operator Companion. A prototype, consisting of operator consoles, expert systems and simulation modules in a distributed architecture, is currently being developed to demonstrate the concepts of the Operator Companion
Elementary operators on self-adjoint operators
Molnar, Lajos; Semrl, Peter
2007-03-01
Let H be a Hilbert space and let and be standard *-operator algebras on H. Denote by and the set of all self-adjoint operators in and , respectively. Assume that and are surjective maps such that M(AM*(B)A)=M(A)BM(A) and M*(BM(A)B)=M*(B)AM*(B) for every pair , . Then there exist an invertible bounded linear or conjugate-linear operator and a constant c[set membership, variant]{-1,1} such that M(A)=cTAT*, , and M*(B)=cT*BT, .
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Online Guide to Choosing a Surgical Residency Practice Management Workshops Patients and Family Patient Education Patient Education ... Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills for Trauma Disaster Management and ...
Your Lung Operation: After Your Operation
Full Text Available ... Education Trauma Education Achieving Zero Preventable Deaths Trauma Systems Conference Advanced Surgical Skills for Exposure in Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills for Trauma Disaster Management ...
Your Lung Operation: After Your Operation
Full Text Available ... as pneumonia and deep vein thrombosis. Jump to: The Day of Your Lung Operation Read Next Your ... and Associates Medical Students International Surgeons Media ACS Links About ACS ACS Foundation Have a ...
Your Lung Operation: After Your Operation
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Nonlocal Operational Calculi for Dunkl Operators
Directory of Open Access Journals (Sweden)
Ivan H. Dimovski
2009-03-01
Full Text Available The one-dimensional Dunkl operator $D_k$ with a non-negative parameter $k$, is considered under an arbitrary nonlocal boundary value condition. The right inverse operator of $D_k$, satisfying this condition is studied. An operational calculus of Mikusinski type is developed. In the frames of this operational calculi an extension of the Heaviside algorithm for solution of nonlocal Cauchy boundary value problems for Dunkl functional-differential equations $P(D_ku = f$ with a given polynomial $P$ is proposed. The solution of these equations in mean-periodic functions reduces to such problems. Necessary and sufficient condition for existence of unique solution in mean-periodic functions is found.
Your Lung Operation: After Your Operation
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Your Lung Operation: After Your Operation
Full Text Available ... Education Trauma Education Achieving Zero Preventable Deaths Trauma Systems Conference Advanced Surgical Skills for Exposure in Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills for Trauma Disaster Management and ...
Your Lung Operation: After Your Operation
Full Text Available ... Mentoring for Excellence in Trauma Surgery Advanced Trauma Life Support Verification, Review, and Consultation Program for Hospitals ... Surgical Skills for Exposure in Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills ...
Stability Operations: Learning from Operation Iraqi Freedom
National Research Council Canada - National Science Library
Clay, Troy A
2007-01-01
.... This paper examines some of these failures and analyzes the importance of security and its influence on using economic means during the initial stages of post-conflict operations to facilitate...
Your Lung Operation: After Your Operation
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Jaeger, Trent
2008-01-01
Operating systems provide the fundamental mechanisms for securing computer processing. Since the 1960s, operating systems designers have explored how to build "secure" operating systems - operating systems whose mechanisms protect the system against a motivated adversary. Recently, the importance of ensuring such security has become a mainstream issue for all operating systems. In this book, we examine past research that outlines the requirements for a secure operating system and research that implements example systems that aim for such requirements. For system designs that aimed to
Training and Tactical Operationally Responsive Space Operations
Sorensen, B.; Strunce, R., Jr.
Current space assets managed by traditional space system control resources provide communication, navigation, intelligence, surveillance, and reconnaissance (ISR) capabilities using satellites that are designed for long life and high reliability. The next generation Operationally Responsive Space (ORS) systems are aimed at providing operational space capabilities which will provide flexibility and responsiveness to the tactical battlefield commander. These capabilities do not exist today. The ORS communication, navigation, and ISR satellites are being designed to replace or supplement existing systems in order to enhance the current space force. These systems are expected to rapidly meet near term space needs of the tactical forces. The ORS concept includes new tactical satellites specifically designed to support contingency operations such as increased communication bandwidth and ISR imagery over the theater for a limited period to support air, ground, and naval force mission. The Concept of Operations (CONOPS) that exists today specifies that in addition to operational control of the satellite, the tasking and scheduling of the ORS tactical satellite for mission data collection in support of the tactical warfighter will be accomplished within the Virtual Mission Operations Center (VMOC). This is very similar to what is currently being accomplished in a fixed Mission Operations Center on existing traditional ISR satellites. The VMOC is merely a distributed environment and the CONOPS remain virtually the same. As a result, there is a significant drawback to the current ORS CONOPS that does not account for the full potential of the ORS paradigm for supporting tactical forces. Although the CONOPS approach may be appropriate for experimental Tactical Satellites (TacSat), it ignores the issues associated with the In-Theater Commander's need to own and operate his dedicated TacSat for most effective warfighting as well as the Warfighter specific CONOPS. What is needed
Ranking Operations Management conferences
Steenhuis, H.J.; de Bruijn, E.J.; Gupta, Sushil; Laptaned, U
2007-01-01
Several publications have appeared in the field of Operations Management which rank Operations Management related journals. Several ranking systems exist for journals based on , for example, perceived relevance and quality, citation, and author affiliation. Many academics also publish at conferences
Heselton, Ken
2004-01-01
Containing key information for operators and managers of large and small plants, this is an indispensable guide for those at advanced and early stages of their careers, as well as for managers interested in reducing operating expenses.
Autonomous Systems and Operations
National Aeronautics and Space Administration — The AES Autonomous Systems and Operations (ASO) project will develop an understanding of the impacts of increasing communication time delays on mission operations,...
National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...
Directory of Open Access Journals (Sweden)
Yuan Jiangtao
2007-01-01
Full Text Available This paper discusses some spectral properties of class operators for , , , and . It is shown that if is a class operator, then the Riesz idempotent of with respect to each nonzero isolated point spectrum is selfadjoint and . Afterwards, we prove that every class operator has SVEP and property , and Weyl's theorem holds for when .
Convolution Operators on Groups
Derighetti, Antoine
2011-01-01
This volume is devoted to a systematic study of the Banach algebra of the convolution operators of a locally compact group. Inspired by classical Fourier analysis we consider operators on Lp spaces, arriving at a description of these operators and Lp versions of the theorems of Wiener and Kaplansky-Helson.
International Nuclear Information System (INIS)
Grenet, G.; Kibler, M.
1978-06-01
A closed polynomial formula for the qth component of the diagonal operator equivalent of order k is derived in terms of angular momentum operators. The interest in various fields of molecular and solid state physics of using such a formula in connection with symmetry adapted operator equivalents is outlined
International Nuclear Information System (INIS)
Satoh, Kotaro
1990-01-01
The present status of the TRISTAN operation is summarized mainly after the installation of superconducting cavities in the 1988 summer shutdown. The paper describes the initial experience of the superconducting cavity operation, the colliding operation at 30.4 GeV and the beam injection. Future improvement is also reported. (author)
Operations and maintenance philosophy
International Nuclear Information System (INIS)
DUNCAN, G.P.
1999-01-01
This Operations and Maintenance (O and M) Philosophy document is intended to establish a future O and M vision, with an increased focus on minimizing worker exposure, ensuring uninterrupted retrieval operations, and minimizing operation life-cycle cost. It is intended that this document would incorporate O and M lessons learned into on-going and future project upgrades
Operational symmetries basic operations in physics
Saller, Heinrich
2017-01-01
This book describes the endeavour to relate the particle spectrum with representations of operational electroweak spacetime, in analogy to the atomic spectrum as characterizing representations of hyperbolic space. The spectrum of hyperbolic position space explains the properties of the nonrelativistic atoms; the spectrum of electroweak spacetime is hoped to explain those of the basic interactions and elementary particles. In this book, the theory of operational symmetries is developed from the numbers, from Plato’s and Kepler’s symmetries over the simple Lie groups to their applications in nonrelativistic, special relativistic and general relativistic quantum theories with the atomic spectrum for hyperbolic position and, in first attempts, the particle spectrum for electroweak spacetime. The standard model of elementary particles and interactions is characterized by a symmetry group. In general, as initiated by Weyl and stressed by Heisenberg, quantum theory can be built as a theory of operation groups an...
Operator licensing examiner standards
International Nuclear Information System (INIS)
1993-01-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes
Aleksandrov, A. B.; Peller, V. V.
2016-08-01
The goal of this survey is a comprehensive study of operator Lipschitz functions. A continuous function f on the real line {R} is said to be operator Lipschitz if \\Vert f(A)-f(B)\\Vert≤slant{const}\\Vert A-B\\Vert for arbitrary self-adjoint operators A and B. Sufficient conditions and necessary conditions are given for operator Lipschitzness. The class of operator differentiable functions on {R} is also studied. Further, operator Lipschitz functions on closed subsets of the plane are considered, and the class of commutator Lipschitz functions on such subsets is introduced. An important role for the study of such classes of functions is played by double operator integrals and Schur multipliers. Bibliography: 77 titles.
Your Lung Operation: After Your Operation
Full Text Available ... Trauma Operative Management Basic Endovascular Skills for Trauma Disaster Management and Emergency Preparedness Rural Trauma Team Development ... 202-5001 (E) postmaster@facs.org Copyright © 1996-2018 by the American College of Surgeons, Chicago, IL ...
Your Lung Operation: After Your Operation
Full Text Available ... and Videos Hotel and Travel Clinical Congress 2017 Future Clinical Congresses MyCME About MyCME About MyCME Claim ... Surgical Skills for Exposure in Trauma Advanced Trauma Life Support Advanced Trauma Operative Management Basic Endovascular Skills ...
Your Lung Operation: After Your Operation
Full Text Available ... Contact My Profile Shop ( 0 ) Cart Donate American College of Surgeons Education Patients and Family Skills Programs Your Lung Operation ... facs.org Copyright © 1996-2018 by the American College of Surgeons, Chicago, IL 60611-3295 | Privacy Policy | Terms of Use
Hermeneutic operative calculus
Ramakrishnan, Sivakumar; Isawasan, Pradeep; Mohanan, Vasuky
2014-07-01
The predicate calculus used currently by mathematical logic in computer science, philosophy and linguistic was found to be too restrictive and inadequate for describing the grammar of natural and artificial language. Therefore many higher order logics have been developed to overcome the limitation of predicate calculus. In this paper a new representation of logic using mathematical principles has been developed for the natural language called Hermeneutic Operative Calculus. This Hermeneutic Operative Calculus is a new language interpretive calculus developed to account for the syntactic, semantic and pragmatic features of natural language and allows removing the restrictions of any particular natural language in the semantic field its map out. The logic of Hermeneutic Operative Calculus capable of represent the syntactic and semantic of factual information of a natural language precisely in any language. The logic of this Hermeneutic Operative Calculus has two different forms of operations called object and meta-operations. The object operation allow for listing the various objects, picturing the various propositions and so forth. The meta-operation would specify what cannot be specified by the object operation like semantical stances of a proposition. The basic operative processes of linguistics and cognitive logic will be mathematically conceptualized and elaborated in this paper.
DEFF Research Database (Denmark)
closely working with, and which are best suited to illuminate a particular aspect of organising and managing global operations in networks. The book addresses the following broadly defined themes: • Contexts of global operations networks, • Configurations of global operations networks, • Capabilities......, international comparative studies providing comprehensive insights from it are still rare. With the objective of bridging this gap, Global Operations Networks (GONE) project (sponsored by the Danish Research Council) brought together numerous academic and industrial partners from Denmark, Sweden and Finland...... of global operations and operations strategy. This summative volume utilises the rich and diverse empirical foundation generated during the project activities in Denmark, Sweden and Finland. Chapters of the book are based on quantitative data and multiple case studies which the project partners have been...
Brandli, A. E.; Eckelkamp, R. E.; Kelly, C. M.; Mccandless, W.; Rue, D. L.
1990-01-01
The objective of an operations management system is to provide an orderly and efficient method to operate and maintain aerospace vehicles. Concepts are described for an operations management system and the key technologies are highlighted which will be required if this capability is brought to fruition. Without this automation and decision aiding capability, the growing complexity of avionics will result in an unmanageable workload for the operator, ultimately threatening mission success or survivability of the aircraft or space system. The key technologies include expert system application to operational tasks such as replanning, equipment diagnostics and checkout, global system management, and advanced man machine interfaces. The economical development of operations management systems, which are largely software, will require advancements in other technological areas such as software engineering and computer hardware.
Energy Technology Data Exchange (ETDEWEB)
1988-01-01
The Nuclear Waste Policy Act of 1982 assigned to the Department of Energy's (DOE) Office of Civilian Waste Management the responsibility for disposing of high-level waste and spent fuel. A significant part of that responsibility involves transporting nuclear waste materials within the federal waste management system; that is, from the waste generator to the repository. The lead responsibility for transportation operations has been assigned to Oak Ridge Operations, with Oak Ridge National Laboratory (ORNL) providing technical support through the Transportation Operations Support Task Group. One of the ORNL support activities involves assessing what facilities, equipment and services are required to assure that an acceptable, cost-effective and safe transportation operations system can be designed, operated and maintained. This study reviews, surveys and assesses the experience of Nuclear Assurance Corporation (NAC) in operating a fleet of spent-fuel shipping casks to aid in developing the spent-fuel transportation system.
International Nuclear Information System (INIS)
1988-01-01
The Nuclear Waste Policy Act of 1982 assigned to the Department of Energy's (DOE) Office of Civilian Waste Management the responsibility for disposing of high-level waste and spent fuel. A significant part of that responsibility involves transporting nuclear waste materials within the federal waste management system; that is, from the waste generator to the repository. The lead responsibility for transportation operations has been assigned to Oak Ridge Operations, with Oak Ridge National Laboratory (ORNL) providing technical support through the Transportation Operations Support Task Group. One of the ORNL support activities involves assessing what facilities, equipment and services are required to assure that an acceptable, cost-effective and safe transportation operations system can be designed, operated and maintained. This study reviews, surveys and assesses the experience of Nuclear Assurance Corporation (NAC) in operating a fleet of spent-fuel shipping casks to aid in developing the spent-fuel transportation system
International Nuclear Information System (INIS)
Marella, J.R.
1995-01-01
A determination of minimum requirements for purge exhaust ventilation system operability has been performed. HLWE and HLW Regulatory Program personnel have evaluated the various scenarios of equipment conditions and HLWE has developed the requirements for purge exhaust systems. This report is provided to document operability requirements to assist Tank Farm personnel to determine whether a system is operable/inoperable and to define required compensatory actions
Cyberwarfare and Operational Art
2017-05-25
warfare within the framework of operational art. The case study evaluated the Russian Federation cyber operations in time and space to support a theory ...case study evaluated the Russian Federation cyber operations in time and space to support a theory that cyber and land force actions can transform...1 Cyberspace manifested on March 18, 1940, when Alan Turing developed the "electromechanical mind ." Turing along with others at Bletchley Park
2012-12-06
draw a qualitative appreciation for the application of theoretical principles during planning and the execution of operational art . The following... History at The United States Center for Military History . John Sloan Brown, "The Maturation of Operational Art : Desert Shield and Desert Storm " in...Historical Perspectives of the Operational Art , ed. Michael D. Krause and R. Cody Phillips (Washington, DC: Center of Military History , 2005), 440
1985-01-01
Long-term and short-term objectives for the development of a network operating system for the Space Station are stated. The short-term objective is to develop a prototype network operating system for a 100 megabit/second fiber optic data bus. The long-term objective is to establish guidelines for writing a detailed specification for a Space Station network operating system. Major milestones are noted. Information is given in outline form.
Operator licensing examiner standards
International Nuclear Information System (INIS)
1987-05-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes
Sunder, V S
2016-01-01
The primarily objective of the book is to serve as a primer on the theory of bounded linear operators on separable Hilbert space. The book presents the spectral theorem as a statement on the existence of a unique continuous and measurable functional calculus. It discusses a proof without digressing into a course on the Gelfand theory of commutative Banach algebras. The book also introduces the reader to the basic facts concerning the various von Neumann–Schatten ideals, the compact operators, the trace-class operators and all bounded operators. .
Arduini, G.; Lamont, M.; Pieloni, T.; Rumolo, G.
The HL-LHC will introduce a number of novel operational features and challenges including luminosity leveling. After a brief recap of the possible leveling techniques, the potential impact of the operational regime on overall efficiency is discussed. A breakdown of the operational cycle and the standard operational year, together with a discussion of fault time is presented. The potential performance is then explored and estimates of the required machine availability and efficiency for 250 fb-1 per year are given. Finally the e-cloud challenges, scrubbing runs requirements, and machine development potential are outlined.
International Nuclear Information System (INIS)
1990-04-01
The Operating Units Status Report --- Licensed Operating Reactors provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management from the Headquarters staff on NRC's Office of Enforcement (OE), from NRC's Regional Offices, and from utilities. The three sections of the report are: monthly highlights and statistics for commercial operating units, and errata from previously reported data; a compilation of detailed information on each unit, provided by NRC's Regional Offices, OE Headquarters and the utilities; and an appendix for miscellaneous information such as spent fuel storage capability, reactor-years of experience and non- power reactors in the US
National Research Council Canada - National Science Library
2007-01-01
...), human rights, rules of engagement, emergency essential civilians supporting military operations, contingency contractor personnel, foreign and deployment, criminal law, environmental law, fiscal law...
International Nuclear Information System (INIS)
1989-11-01
The US Nuclear Regulatory Commission's monthly Licensed Operating Reactors Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. Since all of the data concerning operation of the units is provided by the utility operators less than two weeks after the end of the month, necessary corrections to published information are shown on the errata page
International Nuclear Information System (INIS)
Klinda, J.; Lieskovska, Z.
1998-01-01
Within the Union Nations (UN) framework, the Slovak Republic participated in following activities on environment protection co-operation: UN European Economic Commission, UN Industrial Development Organization, UN Development Programme, UN Human Habitat Organization, UN Environment Programme, and UN Commission on Sustainable Development. Relevant activities of the Slovak Republic in these co-operations as well as in European Union and OECD activities are reviewed. International conventions and other forms of multilateral co-operation, bilateral co-operation, and international programmes and projects in which the Slovak Republic took participate are presented
Operation RANGER. Volume 5. Program Reports - Operational
1952-07-01
Naval Electronics Laboratory, San Diego 52, Calif. Commanding Officer and Director, David Taylor Model Basin, Washington 7, D. C. Chief, Bureau of...By G. A. Kent and B. G. Holzman 3. Ground Instrumentation Provided by Sandia Corporation for Use during Operation Ranger By E. J. Klir.k and R. I...For this reason the most expert forecasting service will be required. It is anticipated that Col. Holzman , Air Weather Service, will be the chief
Operational Transformation In Co-Operative Editing
Directory of Open Access Journals (Sweden)
Mandeep Kaur
2015-08-01
Full Text Available Cooperative Editing Systems in real-time allows a virtual team to view and edit a shared document at the same time. The document shared must be synchronized in order to ensure consistency for all the participants. This paper describes the Operational Transformation the evolution of its techniques its various applications major issues and achievements. In addition this paper will present working of a platform where two users can edit a code programming file at the same time.
Operator interface programs for KSTAR operation
International Nuclear Information System (INIS)
Lee, Sangil; Park, Mikyung; Park, Jinseop; Na, Hoonkyun; Kwon, M.
2013-01-01
Beginning the first plasma discharging experiment of KSTAR since 2008, KSTAR performed the third plasma discharging experiment by 2010. During the experiment of three times, KSTAR OPerator Interface (OPI) programs have been developed for KSTAR operation by itself. OPI programs used in KSTAR were implemented by KSTAR widget plug-in Toolkit (KWT). The KWT means the plug-in library implemented by Qt-based user interface development software. The main purpose of developing the KWT library is to implement full automation libraries having interface with the automated EPICS channel access (CA) guaranteeing the flexibility for requirements of operators. In addition, it has advantages in minimizing human code error and maximizing utilization of the limited human resource. According to the increasing of control systems, a number of OPI servers connected to one EPICS gateway server caused the connection problem and increased the amount of the network data packets. To solve these problems, an algorithm of “CachedChannelAccess” for shared memory base was implemented into an inner logic of the KWT library. KSTAR control system monitoring (CSM) program is one of applications developed by using KWT library. The function of CSM program is to notify alarm to operators by checking health status of every server's network health status and resource (cpu, memory, network packets, disk usage rate and system/user defined process) usage state. Another application is a post-shot sequencing program which is activated after every shot is completed. This application is to display major plasma parameters and diagnostic data in chart form, to save this data to database, and to transfer a chart image file to a web server. This paper describes the technical details how to develop OPI applications which have high productivity using Qt on the EPICS-based control system
Basic Sewage Treatment Operation.
Ontario Ministry of the Environment, Toronto.
This manual was developed for use at workshops designed to introduce operators to the fundamentals of sewage plant operation. The course consists of lecture-discussions and hands-on activities. Each of the lessons has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that topic. Areas covered in…
Hampson, Gregory V; Cook, Steven P; Frederiksen, Steven R
Operation Bali Assist was the Australian Defence Force evacuation of injured Australians and other foreign nationals after the Bali terrorist bombing. This operation was the largest Australian aeromedical evacuation since the Vietnam War. It relied on military and civilian cooperation to move the critically injured initially from Denpasar to Darwin, and then on to specialist units around Australia.
Health care operations management
Carter, M.W.; Hans, Elias W.; Kolisch, R.
2012-01-01
Health care operations management has become a major topic for health care service providers and society. Operations research already has and further will make considerable contributions for the effective and efficient delivery of health care services. This special issue collects seven carefully
Hans, Elias W.; Nieberg, T.
2007-01-01
The operating room (OR) department of a hospital forms the heart of the organization, where the single largest cost is incurred. This document presents and reports on the “Operating Room Manager Game,” developed to give insight into managing a large hospital's OR department at various levels of
Nuclear Powerplant Safety: Operations.
Department of Energy, Washington, DC. Nuclear Energy Office.
Powerplant systems and procedures that ensure the day-to-day health and safety of people in and around the plant is referred to as operational safety. This safety is the result of careful planning, good engineering and design, strict licensing and regulation, and environmental monitoring. Procedures that assure operational safety at nuclear…
Indian Academy of Sciences (India)
First page Back Continue Last page Overview Graphics. Reliance Cell Operator. Reliance was the only bidder for cellular licences for Assam and NE. Services allowed only in Guwahati and Shillong due to “security reasons”. Only major cities in the country with only one operator.
Directory of Open Access Journals (Sweden)
Sergio Arturo Celani
2006-01-01
Full Text Available We characterize the simple and subdirectly irreducible distributive algebras in some varieties of distributive lattices with unary operators, including topological and monadic positive modal algebras. Finally, for some varieties of Heyting algebras with operators we apply these results to determine the simple and subdirectly irreducible algebras.
Operation auxiliary system (SAO)
International Nuclear Information System (INIS)
Lolich, J.; Santome, D.; Drexler, J.
1990-01-01
This work presents an auxiliary system for nuclear power plants operation (SAO). The development purpose consisted in a computing supervision system to be installed at different sites of a reactor, mainly in the control room. The inclusion of this system to a nuclear power plant minimizes the possibility of human error for the facility operation. (Author) [es
DEFF Research Database (Denmark)
Gardner, Richard J.; Kiderlen, Markus
A structural theory of operations between real-valued (or extended-real-valued) functions on a nonempty subset A of Rn is initiated. It is shown, for example, that any operation ∗ on a cone of functions containing the constant functions, which is pointwise, positively homogeneous, monotonic...
Marine Corps Inst., Washington, DC.
Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on crane and excavator operation is designed to enable the crane and excavator operator to perform his/her duties more proficiently. Introductory materials include specific information for MCI students, a course introduction, and a study guide…
Elliptic Quadratic Operator Equations
Ganikhodjaev, Rasul; Mukhamedov, Farrukh; Saburov, Mansoor
2017-01-01
In the present paper is devoted to the study of elliptic quadratic operator equations over the finite dimensional Euclidean space. We provide necessary and sufficient conditions for the existence of solutions of elliptic quadratic operator equations. The iterative Newton-Kantorovich method is also presented for stable solutions.
Faris, Grant
2012-01-01
Integrate the mission operations assurance function into the flight team providing: (1) value added support in identifying, mitigating, and communicating the project's risks and, (2) being an essential member of the team during the test activities, training exercises and critical flight operations.
Indian Academy of Sciences (India)
and includes virtual memory, shared libraries, demand loading, ... Memory Management is a scheme by which an operating system shares the memory in a computer ..... Suggested Reading and Websites. [1] Andrew S Tannenbaum and Albert S Woodhull,. Operating Systems: Design and Implementation,. Second Edition ...
Tanenbaum, A.S.; van Renesse, R.
1985-01-01
Distributed operating systems have many aspects in common with centralized ones, but they also differ in certain ways. This paper is intended as an introduction to distributed operating systems, and especially to current university research about them. After a discussion of what constitutes a
Technical Concept - Operation Bren
1962-01-01
and consonant with safe operation of those facilities. C-1, C-4, and C-6 (see the organization chart on p. 20) shall be responsible to the TD for...source will be shipped to NTS in accordance with AEC regulations. 19 Chapter 8 ORGANIZATION AND RESPONSIBILITIES The organization chart for Operation
Directory of Open Access Journals (Sweden)
Ovidiu T. Pop
2007-01-01
Full Text Available Using the method of Jakimovski and Leviatan from their work in 1969, we construct a general class of linear positive operators. We study the convergence, the evaluation for the rate of convergence in terms of the first modulus of smoothness and we give a Voronovskaja-type theorem for these operators.
Generalizations of OWA Operators
Czech Academy of Sciences Publication Activity Database
Mesiar, Radko; Stupňanová, A.; Yager, R. R.
2015-01-01
Roč. 23, č. 6 (2015), s. 2154-2152 ISSN 1063-6706 Institutional support: RVO:67985556 Keywords : Choquet integral * ordered modular average (OMA) operator * ordered weighted average (OWA) operator Subject RIV: BA - General Mathematics Impact factor: 6.701, year: 2015 http://library.utia.cas.cz/separaty/2015/E/mesiar-0453103.pdf
South Carolina State Dept. of Education, Columbia. Office of Vocational Education.
This module on special operations, one in a series dealing with industrial sewing machines, their attachments, and operation, covers two topics: topstitching and mitering. For each topic these components are provided: an introduction, directions, an objective, learning activities, student information, a student self-check, and a check-out…
2014-06-01
operations such as food and furniture deliveries, maintenance operations, event manager companies, etc. An app called gMobiMate would be available for...vehicles by providing them with a smart routing and attachment of documents to give more information about the tasks or incidents. 35. The third form
International Nuclear Information System (INIS)
McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.
1982-03-01
The CANDU Pressurized Heavy Water (CANDU-PHW) type of nuclear electric generating station has been developed jointly by Atomic Energy of Canada Limited and Ontario Hydro. This paper highlights Ontario Hydro's operating experience using the CANDU-PHW system, with a focus on the operating performance and costs, reliability of system components and nuclear safety considerations both to the workers and the public
Waterworks Operator Training Manual.
Missouri Univ., Columbia. Instructional Materials Lab.
Sixteen self-study waterworks operators training modules are provided. Module titles are the following: basic mathematics, basic chemistry, analysis procedures, microbiology, basic electricity, hydraulics, chlorination, plant operation, surface water, ground water, pumps, cross connections, distribution systems, safety, public relations, and…
Aircraft operations management manual
1992-01-01
The NASA aircraft operations program is a multifaceted, highly diverse entity that directly supports the agency mission in aeronautical research and development, space science and applications, space flight, astronaut readiness training, and related activities through research and development, program support, and mission management aircraft operations flights. Users of the program are interagency, inter-government, international, and the business community. This manual provides guidelines to establish policy for the management of NASA aircraft resources, aircraft operations, and related matters. This policy is an integral part of and must be followed when establishing field installation policy and procedures covering the management of NASA aircraft operations. Each operating location will develop appropriate local procedures that conform with the requirements of this handbook. This manual should be used in conjunction with other governing instructions, handbooks, and manuals.
Assessing Operational Situations
DEFF Research Database (Denmark)
Zhang, Xinxin
In spite of the high level of automation commonly applied to today’s engineering system, humans’ skill and knowledge still plays a central role in the systems’ daily operation, critical decision making, and accident management. The complexity of the engineered system poses great challenge for human...... operators to perceive and understand the operational situation. The research domain of situation awareness approaches the operational challenges from the human cognition perspective while the presented thesis aims at supporting situation assessment from the system perspective. The thesis has reviewed...... different perspectives on situation awareness in the human factor studies and uses the knowledge reflectively for system representation and analysis. The human cognitive activities during complex plant operation and how they perceive a situation and what kind of knowledge has to be established in the human...
Sustainable Building Operation
DEFF Research Database (Denmark)
Jensen, Jesper Ole
2009-01-01
building operation as an 'umbrella' for various ways of reducing flows of energy, water and waste in the daily operation of the buildings, for instance by regular monitoring the consumption, by using 'green accounting', by applying policies for sustainability etc. The paper is based on case studies...... of sustainable building operation and a survey amongst building administrators from the private and the social housing sector. Our results show that there are many good examples on sustainable building operation in Danish housing estates, where local building managers, residents etc. have gained impressive...... results. In the broader sense, however, there is a limited used of available methods and technologies. Barriers for the use of sustainable building operation have been identified, and related to different types of ownership (social housing, private rented, owner-occupied and private co-ops). The survey...
Tanenbaum, Andrew S
2015-01-01
Modern Operating Systems, Fourth Edition, is intended for introductory courses in Operating Systems in Computer Science, Computer Engineering, and Electrical Engineering programs. It also serves as a useful reference for OS professionals ' The widely anticipated revision of this worldwide best-seller incorporates the latest developments in operating systems (OS) technologies. The Fourth Edition includes up-to-date materials on relevant'OS. Tanenbaum also provides information on current research based on his experience as an operating systems researcher. ' Modern Operating Systems, Third Editionwas the recipient of the 2010 McGuffey Longevity Award. The McGuffey Longevity Award recognizes textbooks whose excellence has been demonstrated over time.'http://taaonline.net/index.html " Teaching and Learning Experience This program will provide a better teaching and learning experience-for you and your students. It will help: ' *Provide Practical Detail on the Big Picture Concepts: A clear and entertaining writing s...
International Nuclear Information System (INIS)
Decreton, M.
1998-01-01
Maintenance, repair, and dismantling operations in nuclear facilities have to be performed remotely when high radiation doses exclude hands-on operation, but also to minimize contamination risks and occupational doses to the operators. Computer-aided and sensor-based tele-operation enhances safety, reliability, and performance by helping the operator in difficult tasks with poor remote environmental perception. The objectives of work in this domain are to increase the scientific knowledge of the studied phenomena, to improve the interpretation of data, to improve the piloting og experimental devices during irradiation, to reveal and to understand possible unexpected phenomena occurring during irradiation. This scientific report describes the achievements for 1997 in the area of radiation tolerance for of remote-sensing, optical fibres and optical fibre sensors
Gohberg, Israel
2001-01-01
rii application of linear operators on a Hilbert space. We begin with a chapter on the geometry of Hilbert space and then proceed to the spectral theory of compact self adjoint operators; operational calculus is next presented as a nat ural outgrowth of the spectral theory. The second part of the text concentrates on Banach spaces and linear operators acting on these spaces. It includes, for example, the three 'basic principles of linear analysis and the Riesz Fredholm theory of compact operators. Both parts contain plenty of applications. All chapters deal exclusively with linear problems, except for the last chapter which is an introduction to the theory of nonlinear operators. In addition to the standard topics in functional anal ysis, we have presented relatively recent results which appear, for example, in Chapter VII. In general, in writ ing this book, the authors were strongly influenced by re cent developments in operator theory which affected the choice of topics, proofs and exercises. One ...
Stirling machine operating experience
Energy Technology Data Exchange (ETDEWEB)
Ross, B. [Stirling Technology Co., Richland, WA (United States); Dudenhoefer, J.E. [Lewis Research Center, Cleveland, OH (United States)
1994-09-01
Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that stirling machines are capable of reliable and lengthy operating lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and are not expected to operate for lengthy periods of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered. The record in this paper is not complete, due to the reluctance of some organizations to release operational data and because several organizations were not contacted. The authors intend to repeat this assessment in three years, hoping for even greater participation.
The Battle for Crete (Operation Mercury): An Operational Analysis
2001-05-18
NAVAL WAR COLLEGE Newport, R.I. The Battle for Crete (Operation Mercury ): An Operational Analysis by Kenneth J. Cox Lieutenant Colonel, U.S. Army...Title (Include Security Classification): The Battle for Crete (Operation Mercury ): An Operational Analysis (UNCLASSIFIED) 9. Personal Authors...Security Classification of this page Unclassified 3 ABSTRACT The Battle for Crete (Operation Mercury ): An Operational Analysis In May
Energy Technology Data Exchange (ETDEWEB)
Lee, Young Jae; Lee, Hae Cho; Lee, Ho Yeun; Kim, Young Taek; Lee, Sung Kyu; Park, Jeong Suk; Nam, Ji Wha; Kim, Soon Kon; Yang, Sung Un; Sohn, Jae Min; Moon, Soon Sung; Park, Bong Sik; Lee, Byung Heon; Park, Sun Hee; Kim, Jin Hee; Hwang, Hyeoi Sun; Lee, Hee Ja; Hwang, In A. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1993-12-01
The report described the operation and the trouble shooting of main computer and KAERINet. The results of the project are as follows; 1. The operation and trouble shooting of the main computer system. (Cyber 170-875, Cyber 960-31, VAX 6320, VAX 11/780). 2. The operation and trouble shooting of the KAERINet. (PC to host connection, host to host connection, file transfer, electronic-mail, X.25, CATV etc.). 3. The development of applications -Electronic Document Approval and Delivery System, Installation the ORACLE Utility Program. 22 tabs., 12 figs. (Author) .new.
International Nuclear Information System (INIS)
Plaziat, J.F.; Moulin, P.; Van Beurden, R.; Ballet, E.
2005-01-01
Building an internal gas market implies establishing harmonized rules for cross border trading between operators. To that effect, the European association EASEE-gas is carrying out standards and procedures, commonly called 'inter-operability'. Set up in 2002, the Association brings together all segments of the gas industry: producers, transporters, distributors, traders and shippers, suppliers, consumers and service providers. This workshop presents the latest status on issues such as barriers to gas trade in Europe, rules and procedures under preparation by EASEE-gas, and the implementation schedule of these rules by operators. This article gathers 5 presentations about this topic given at the gas conference
Operational proof of automation
International Nuclear Information System (INIS)
Jaerschky, R.; Reifenhaeuser, R.; Schlicht, K.
1976-01-01
Automation of the power plant process may imply quite a number of problems. The automation of dynamic operations requires complicated programmes often interfering in several branched areas. This reduces clarity for the operating and maintenance staff, whilst increasing the possibilities of errors. The synthesis and the organization of standardized equipment have proved very successful. The possibilities offered by this kind of automation for improving the operation of power plants will only sufficiently and correctly be turned to profit, however, if the application of these technics of equipment is further improved and if its volume is tallied with a definite etc. (orig.) [de
Computerized operator decision aids
International Nuclear Information System (INIS)
Long, A.B.
1984-01-01
This article explores the potential benefits associated with the use of computers in nuclear plants by the operating crew as an aid in making decisions. Pertinent findings are presented from recently completed projects to establish the context in which operating decisions have to be made. Key factors influencing the decision-making process itself are also identified. Safety parameter display systems, which are being implemented in various forms by the nuclear industry, are described within the context of decision making. In addition, relevant worldwide research and development activities are examined as potential enhancements to computerized operator decision aids to further improve plant safety and availability
International Nuclear Information System (INIS)
McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.; Thurygill, E.W.
1980-05-01
The CANDU-PHW program is based upon 38 years of heavy water reactor experience with 35 years of operating experience. Canada has had 72 reactor years of nuclear-electric operations experience with 10 nuclear units in 4 generating stations during a period of 18 years. All objectives have been met with outstanding performance: worker safety, public safety, environmental emissions, reliable electricity production, and low electricity cost. The achievement has been realized through total teamwork involving all scientific disciplines and all project functions (research, design, manufacturing, construction, and operation). (auth)
Information Operations: Where Next?
National Research Council Canada - National Science Library
Buchholz, David R
2005-01-01
... to standardized IO training and integration across the combatant commands. For this reason and others there is a compelling argument for the major responsibility for DoD information operations integration to fall under the control of U.S...
Nuclear material operations manual
International Nuclear Information System (INIS)
Tyler, R.P.
1981-02-01
This manual provides a concise and comprehensive documentation of the operating procedures currently practiced at Sandia National Laboratories with regard to the management, control, and accountability of nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion
Payroll Operational Data Store
Social Security Administration — The Payroll ODS will provide a single repository of payroll data to produce accurate and timely financial reports to support operating, budget, and policy decisions.
Energy Technology Data Exchange (ETDEWEB)
NONE
1997-10-01
This document is the first edition of Argonne`s new Operating Plan. The Operating Plan complements the strategic planning in the Laboratory`s Institutional Plan by focusing on activities that are being pursued in the immediate fiscal year, FY 1998. It reflects planning that has been done to date, and it will serve in the future as a resource and a benchmark for understanding the Laboratory`s performance. The heart of the Institutional Plan is the set of major research initiatives that the Laboratory is proposing to implement in future years. In contrast, this Operating Plan focuses on Argonne`s ongoing R&D programs, along with cost-saving measures and other improvements being implemented in Laboratory support operations.
Department of Homeland Security — This map layer includes crushed stone operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...
Operations Strategy in practice
DEFF Research Database (Denmark)
Rytter, Niels Gorm; Koch, Christian; Boer, Harry
2005-01-01
In this paper, we describe and illustrate a new, action-based longitudinal case study approach, which aims at helping scholars narrow the gap between the theory and practice of Operations Strategy (OS). First, we elaborate on the need for new research methods for studying OS in practice. Then, we...... and disadvantages of the method. Finally, we draw conclusions on its potential for operations strategy and operations management studies.......In this paper, we describe and illustrate a new, action-based longitudinal case study approach, which aims at helping scholars narrow the gap between the theory and practice of Operations Strategy (OS). First, we elaborate on the need for new research methods for studying OS in practice. Then, we...
International Nuclear Information System (INIS)
1989-08-01
THE OPERATING UNITS STATUS REPORT - LICENSED OPERATING REACTORS provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management from the Headquarters staff of NRC's Office of Enforcement (OE), from NRC's Regional Offices, and from utilities. The three sections of the report are: monthly highlights and statistics for commercial operating units, and errata from previously reported data; a compilation of detailed information on each unit, provided by NRC's Regional Offices, OE Headquarters and the utilities; and an appendix for miscellaneous information such as spent fuel storage capability, reactor-years of experience and non-power reactors in the US
Administrative & Operational Circulars - Reminder
HR Department
2011-01-01
All Administrative and Operational Circulars are available on the intranet site of the Human Resources Department at the following address: http://cern.ch/hr-docs/admincirc/admincirc.asp Department Head Office
Construction Minerals Operations
Department of Homeland Security — This map layer includes construction minerals operations in the United States. The data represent commodities covered by the Minerals Information Team (MIT) of the...
Department of Homeland Security — This map layer includes sand and gravel operations in the United States. These data were obtained from information reported voluntarily to the USGS by the aggregate...
International Nuclear Information System (INIS)
Cimesa, S.
2007-01-01
Slovenian Nuclear Safety Administration (SNSA) has developed its own system for tracking, screening and evaluating the operating experiences of the nuclear installations. The SNSA staff regularly tracks the operating experiences throughout the world and screens them on the bases of applicability for the Slovenian nuclear facilities. The operating experiences, which pass the screening, are thoroughly evaluated and also recent operational events in these facilities are taken into account. If needed, more information is gathered to evaluate the conditions of the Slovenian facilities and appropriate corrective actions are considered. The result might be the identification of the need for modification at the licensee, the need for modification of internal procedures in the SNSA or even the proposal for the modification of regulations. Information system helps everybody to track the process of evaluation and proper logging of activities. (author)
U.S. Environmental Protection Agency — This dataset consists of operable unit data from multiple Superfund sites in U.S. EPA Region 8. These data were acquired from multiple sources at different times and...
Observer's Report - Okinawa Operation
National Research Council Canada - National Science Library
Todd, W. N., Jr
1945-01-01
... for temporary duty in connection with the Okinawa Operation. By verbal agreement between observers, it was decided that each officer would cover certain activities and thus have a complete coverage without duplication...
International Nuclear Information System (INIS)
Church, B.W.
1981-01-01
A brief overview is given of weapon test site decontamination activities carried out by Nevada Operations Office. Tabulated data is given of event name, date, location, year of cleanup, and radioisotopes that were present, activity levels, and cost of cleanup
International Nuclear Information System (INIS)
1991-08-01
The Nuclear Regulatory Commission's annual summary of licensed nuclear power reactor data is based primarily on the report of operating data submitted by licensees for each unit for the month of December because that report contains data for the month of December, the year to date (in this case calendar 1990) and cumulative data, usually from the date of commercial operation. The data is not independently verified, but various computer checks are made. The report is divided into two sections. The first contains summary highlights and the second contains data on each individual unit in commercial operation. Section 1 capacity and availability factors are simple arithmetic averages. Section 2 items in the cumulative column are generally as reported by the licensee and notes as to the use of weighted averages and starting dates other than commercial operation are provided
International Nuclear Information System (INIS)
Flinchem, J.
1980-01-01
This document contains procedures which apply to operations performed on individual P-1c machines in the Machine Interface Test System (MITS) at AiResearch Manufacturing Company's Torrance, California Facility
Operant Conditioning and Education.
de Noronha, Mario
A case study of a learning disabled 8-year-old with behavior disturbancs is presented to highlight the use of operant conditioning in cutting down educational costs and easing the teacher's class management problems. (CL)
Information Operations: Where Next?
National Research Council Canada - National Science Library
Buchholz, David R
2005-01-01
... (DoD) information operations. Doctrine already addresses the issue of combatant commander responsibility for ensuring that IO is planned and executed in the respective commands, but an IO vacuum exists with respect...
Nuclear material operations manuals
International Nuclear Information System (INIS)
Tyler, R.P.
1979-06-01
This manual is intended to provide a concise and comprehensive documentation of the operating procedures currently practiced at Sandia Laboratories with regard to the management, control, and accountability of radioactive and nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion
LCOGT network observatory operations
Pickles, Andrew; Hjelstrom, Annie; Boroson, Todd; Burleson, Ben; Conway, Patrick; De Vera, Jon; Elphick, Mark; Haworth, Brian; Rosing, Wayne; Saunders, Eric; Thomas, Doug; White, Gary; Willis, Mark; Walker, Zach
2014-08-01
We describe the operational capabilities of the Las Cumbres Observatory Global Telescope Network. We summarize our hardware and software for maintaining and monitoring network health. We focus on methodologies to utilize the automated system to monitor availability of sites, instruments and telescopes, to monitor performance, permit automatic recovery, and provide automatic error reporting. The same jTCS control system is used on telescopes of apertures 0.4m, 0.8m, 1m and 2m, and for multiple instruments on each. We describe our network operational model, including workloads, and illustrate our current tools, and operational performance indicators, including telemetry and metrics reporting from on-site reductions. The system was conceived and designed to establish effective, reliable autonomous operations, with automatic monitoring and recovery - minimizing human intervention while maintaining quality. We illustrate how far we have been able to achieve that.
Nuclear material operations manual
Energy Technology Data Exchange (ETDEWEB)
Tyler, R.P.
1981-02-01
This manual provides a concise and comprehensive documentation of the operating procedures currently practiced at Sandia National Laboratories with regard to the management, control, and accountability of nuclear materials. The manual is divided into chapters which are devoted to the separate functions performed in nuclear material operations-management, control, accountability, and safeguards, and the final two chapters comprise a document which is also issued separately to provide a summary of the information and operating procedures relevant to custodians and users of radioactive and nuclear materials. The manual also contains samples of the forms utilized in carrying out nuclear material activities. To enhance the clarity of presentation, operating procedures are presented in the form of playscripts in which the responsible organizations and necessary actions are clearly delineated in a chronological fashion from the initiation of a transaction to its completion.
1980-05-28
An evaluation of the utility of lighter-than-air vehicles (airships) for Alaskan service suggests that very large vehicles operating at low speeds would transport heavy loads to remote areas with excellent fuel economy, but that the potential market ...
Operator licensing examiner standards
International Nuclear Information System (INIS)
1983-10-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining and licensing of applicants for NRC operator licenses pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). They are intended to assist NRC examiners and facility licensees to understand the examination process better and to provide for equitable and consistent administration of examinations to all applicants by NRC examiners. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator examination licensing policy changes. As appropriate, these standards will be revised periodically to accommodate comments and reflect new information or experience
International Nuclear Information System (INIS)
Sackett, J.I.; Allen, N.L.; Dean, E.M.; Fryer, R.M.; Larson, H.A.; Lehto, W.K.
1978-01-01
The mission of the Experimental Breeder Reactor II (EBR-II) has envolved from that of a small LMFBR demonstration plant to a major irradiation-test facility. Because of that evolution, many operational-safety issues have been encountered. This paper describes the EBR-II operational-safety experience in four areas: protection-system design, safety-document preparation, tests of off-normal reactor conditions, and tests of elements with breached cladding. (author)
International Nuclear Information System (INIS)
McConnell, L.G.; Woodhead, L.W.; Fanjoy, G.R.
1982-09-01
The CANDU (CANada Deuterium Uranium) Pressurized Heavy Water (PHW) type of nuclear-electric generating station was developed jointly by Atomic Energy of Canada Limited and Ontario Hydro. This paper summarizes Ontario Hydro's operating experience using the CANDU-PHW system, with a focus on the operating performance and costs, reliability of system components, and nuclear safety considerations to both the workers and the public
Hansen, Frank; Pedersen, Gert K.
2002-01-01
We establish what we consider to be the definitive versions of Jensen's operator inequality and Jensen's trace inequality for functions defined on an interval. This is accomplished by the introduction of genuine non-commutative convex combinations of operators, as opposed to the contractions used in earlier versions of the theory. As a consequence, we no longer need to impose conditions on the interval of definition. We show how this relates to the pinching inequality of Davis, and how Jensen...
Operational Waste Volume Projection
Energy Technology Data Exchange (ETDEWEB)
STRODE, J.N.
1999-08-24
Waste receipts to the double-shell tank system are analyzed and wastes through the year 2018 are projected based on assumption as of July 1999. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement.
JIRKŮ, Radek
2012-01-01
This thesis introduces readers to the MINIX operating system, which was used in the creation of the Linux OS. It discusses the history and development of the system and explains its core and the file system. Also solves MINIX installation and configuration of the virtual machine at each step and deals with disputes that had a creator of Minix creator of Linux. In conclusion, compared with Linux MINIX and summarizes the advantages and disadvantages and the use of the operating system at present.
Gabriela ANGHELACHE; Ana Cornelia OLTEANU
2011-01-01
Losses resulting from operational risk events from a complex interaction between organizational factors, personal and market participants that do not fit a simple classification scheme. Taking into account past losses (ex. Barings, Daiwa, etc.) we can say that operational risk is a major financial losses in the banking sector, although until recently have been underestimated, considering that they are generally minor, note setting survival of a bank.
Gabriela ANGHELACHE; Ana-Cornelia OLTEANU (PUIU); Alina-Nicoleta RADU
2010-01-01
Beginning with the fact that performant strategies of the financial institutions have programmes and management procedures for the banking risks, which have as main objective to minimize the probability of risk generation and the bank’s potential exposure, this paper wants to present the operational risk measurement. Therefore, the first part presents the conceptual approach of the operational risks through the point of view of the financial institutions exposed to this type of risk. The seco...
2008-09-01
Mittel als Faktoren strategischer Zielsetzung. Ueberlegungen zu Napoleons Feldzug in Russland 1812 (Hamburg: Fuehrungs- akademie der Bundeswehr, November...continuous recon- naissance and surveillance of the basing and operating areas of the enemy forces. To achieve success in the main sector, it is...operation lies in uninterrupted recon- naissance /surveillance and good intelligence on the enemy’s situation, a high state of combat readiness and
Rotations in Stability Operations
2012-04-25
forces to the protected population .” An “ overwhelming presence” was essential to the initial success in Haiti and an “inadequate” number of troops was...stability operations until they achieve the endstate rather than rotating them allows the military to use overwhelming presence, successfully handle...must deploy a force that provides an overwhelming presence in the area of operations with the mission to achieve the endstate. 14. SUBJECT
Power reactors operational diagnosis
International Nuclear Information System (INIS)
Dach, K.; Pecinka, L.
1976-01-01
The definition of reactor operational diagnostics is presented and the fundamental trends of research are determined. The possible sources of power reactor malfunctions, the methods of defect detection, the data evaluation and the analysis of the results are discussed in detail. In view of scarcity of a theoretical basis and of insufficient in-core instrumentation, operational diagnostics cannot be as yet incorporated in a computer-aided reactor control system. (author)
Quality in drilling operations
Energy Technology Data Exchange (ETDEWEB)
Duncan, E.; Gervais, I. [Sedco Forex Jacintoport Facility, Channelview, TX (United States); Le Moign, Y.; Pangarkar, S.; Stibbs, B. [Sedco Forex, Montrouge (France); McMorran, P. [Sedco Forex, Pau (France); Nordquist, E. [Dubai Petroleum Company, Dubai (United Arab Emirates); Pittman, T. [Sedco Forex, Perth (Australia); Schindler, H. [Sedco Forex, Dubai (United Arab Emirates); Scott, P. [Woodside Offshore Petroleum Pty. Ltd., Perth (Australia)
1996-12-31
Driven by cost and profitability pressures, quality has taken on new meaning and importance in the oil field during the past decade. In drilling operations, new initiatives have led to cooperative team efforts between operators and drilling contractors to enhance quality. In this article examples are given of how one drilling contractor, by adopting a quality culture, is reaping major benefits for its clients as well as its employees. 22 figs., 19 refs.
Operational Waste Volume Projection
Energy Technology Data Exchange (ETDEWEB)
STRODE, J.N.
2000-08-28
Waste receipts to the double-shell tank system are analyzed and wastes through the year 2015 are projected based on generation trends of the past 12 months. A computer simulation of site operations is performed, which results in projections of tank fill schedules, tank transfers, evaporator operations, tank retrieval, and aging waste tank usage. This projection incorporates current budget planning and the clean-up schedule of the Tri-Party Agreement. Assumptions were current as of June. 2000.
Directory of Open Access Journals (Sweden)
Gabriela ANGHELACHE
2011-06-01
Full Text Available Losses resulting from operational risk events from a complex interaction between organizational factors, personal and market participants that do not fit a simple classification scheme. Taking into account past losses (ex. Barings, Daiwa, etc. we can say that operational risk is a major financial losses in the banking sector, although until recently have been underestimated, considering that they are generally minor, note setting survival of a bank.
International Nuclear Information System (INIS)
Bodington, J.C.
1991-01-01
This article addresses the evaluation of power projects for the purpose of determining their marketability. The topics of the article include deciding to sell, reasons to buy, appraising a project, determining worth of the project assets as well as the operating project itself, and negotiating the deal. With a comprehensive understanding of a project's worth, and strict attention to the details of a sales agreement, ownership of operating independent energy facilities can be transferred with maximum benefit for both buyer and seller
International Nuclear Information System (INIS)
Puglisi, M.; Cornacchia, M.
1981-01-01
The need for a very low final amplifier output impedance, always associated with class A operation, requires a very large power waste in the final tube. The recently suggested pulsed rf operation, while saving a large amount of power, increases the inherent final amplifier non linearity. A method is presented for avoiding the large signal non linear analysis and it is shown how each component of the beam induced voltage depends upon all the beam harmonics via some coupling coefficients which are evaluated
Rudić, Ratko
2016-01-01
This thesis outlines history, development and design of microkernel based operating systems. While the idea of microkernel based architecture emerged early in computer science, there are still very few systems adopting this technology. Microkernel operating systems are divided into several different groups and families that frequently share rules, design decisions and development processes. This master thesis focuses on the main representatives of these groups as well as their mutual...
Operating experience: safety perspective
International Nuclear Information System (INIS)
Piplani, Vivek; Krishnamurthy, P.R.; Kumar, Neeraj; Upadhyay, Devendra
2015-01-01
Operating Experience (OE) provides valuable information for improving NPP safety. This may include events, precursors, deviations, deficiencies, problems, new insights to safety, good practices, lessons and corrective actions. As per INSAG-10, an OE program caters as a fundamental means for enhancing the defence-in-depth at NPPs and hence should be viewed as ‘Continuous Safety Performance Improvement Tool’. The ‘Convention on Nuclear Safety’ also recognizes the OE as a tool of high importance for enhancing the NPP safety and its Article 19 mandates each contracting party to establish an effective OE program at operating NPPs. The lessons drawn from major accidents at Three Mile Island, Chernobyl and Fukushima Daiichi NPPs had prompted nuclear stalwarts to change their safety perspective towards NPPs and to frame sound policies on issues like safety culture, severe accident prevention and mitigation. An effective OE program, besides correcting current/potential problems, help in proactively improving the NPP design, operating and maintenance procedures, practices, training, etc., and thus plays vital role in ensuring safe and efficient operation of NPPs. Further it enhances knowledge with regard to equipment operating characteristics, system performance trends and provides data for quantitative and qualitative safety analysis. Besides all above, an OE program inculcates a learning culture in the organisation and thus helps in continuously enhancing the expertise, technical competency and knowledge base of its staff. Nuclear and Radiation Facilities in India are regulated by Atomic Energy Regulatory Board (AERB). Operating Plants Safety Division (OPSD) of AERB is involved in managing operating experience activities. This paper provides insights about the operating experience program of OPSD, AERB (including its on-line data base namely OPSD STAR) and its utilisation in improving the regulations and safety at Indian NPPs/projects. (author)
2010-11-01
competitive civil service selection process. Mr. Mark H. Johnson ( DISES ) is the Director of JIOWC, and USAR Colonel Vincent D. Crabb is the Deputy...of Public Affairs (PA), Civil -Military Operations (CMO), and Defense Support to Public Diplomacy (DSPD) contribute to the accomplishment of the IO...and internal publics with interest in the Department of Defense. 6 (2) Civil -Military Operations (CMO) are the activities of a commander that
Varsi, Giulio
In the last decade, the operation of a spacecraft after launch has emerged as a major component of the total cost of the mission. This trend is sustained by the increasing complexity, flexibility, and data gathering capability of the space assets and by their greater reliability and consequent longevity. The trend can, however, be moderated by the progressive transfer of selected functions from the ground to the spacecraft and by application, on the ground, of new technology. Advances in ground operations derive from the introduction in the mission operations environment of advanced microprocessor-based workstations in the class of a few million instructions per second and from the selective application of artificial intelligence technology. In the last few years a number of these applications have been developed, tested in operational settings and successfully demonstrated to users. Some are now being integrated in mission operations facilities. An analysis of mission operations indicates that the key areas are: concurrent control of multiple missions; automated/interactive production of command sequences of high integrity at low cost; automated monitoring of spacecraft health and automated aides for fault diagnosis; automated allocation of resources; automated processing of science data; and high-fidelity, high-speed spacecraft simulation. Examples of major advances in selected areas are described.
Pipeline system operability review
Energy Technology Data Exchange (ETDEWEB)
Eriksson, Kjell [Det Norske Veritas (Norway); Davies, Ray [CC Technologies, Dublin, OH (United States)
2005-07-01
Pipeline operators are continuously working to improve the safety of their systems and operations. In the US both liquid and gas pipeline operators have worked with the regulators over many years to develop more systematic approaches to pipeline integrity management. To successfully manage pipeline integrity, vast amounts of data from different sources needs to be collected, overlaid and analyzed in order to assess the current condition and predict future degradation. The efforts undertaken by the operators has had a significant impact on pipeline safety, nevertheless, during recent years we have seen a number of major high profile accidents. One can therefore ask how effective the pipeline integrity management systems and processes are. This paper will present one methodology 'The Pipeline System Operability Review' that can evaluate and rate the effectiveness of both the management systems and procedures, as well as the technical condition of the hardware. The result from the review can be used to compare the performance of different pipelines within one operating company, as well as benchmark with international best practices. (author)
Reactor operational transient analysis
International Nuclear Information System (INIS)
Shin, W.K.; Chae, S.K.; Han, K.I.; Yang, K.S.; Chung, H. D.; Kim, H.G.; Moon, H.J.; Ryu, Y.H.
1983-01-01
To build up efficient capability of safety review and inspection for the nuclear power plants, four area of studies have performed as follows: 1) In order to search the most optimized operating method during load follow operating schemes, automatic control and normal control, are compared each other under the CAOC condition. The analysis performed by DDID code has shown that the reactor has to be controlled by the operator manually during load follow operation. 2) Through the sensitivity analysis by COBRA code, the operating parameters, such as coolant pressure, flow rate, inlet temperature, and power distribution are shown to be important to the determination of DNBR. Expecially, inlet temperature of primary coolant system is appeared as the most senstive parameter on DNBR. 3) FRAPCON code is adapted to study the sensitivity of several operational parameters on the mechanical properties of reactor fuel rod. 4) The calculations procedure which is required to be obtained the neutron fluence at the reactor vessel and the spectrum at the surveillance capsule is established. The results of computation are conpared with those of FSAR and SWRI report and proved its applicability to reactor surveillance program. (Author)
Operator licensing examiner standards
International Nuclear Information System (INIS)
1994-06-01
The Operator Licensing Examiner Standards provide policy and guidance to NRC examiners and establish the procedures and practices for examining licensees and applicants for reactor operator and senior reactor operator licenses at power reactor facilities pursuant to Part 55 of Title 10 of the Code of Federal Regulations (10 CFR 55). The Examiner Standards are intended to assist NRC examiners and facility licensees to better understand the initial and requalification examination processes and to ensure the equitable and consistent administration of examinations to all applicants. These standards are not a substitute for the operator licensing regulations and are subject to revision or other internal operator licensing policy changes. Revision 7 was published in January 1993 and became effective in August 1993. Supplement 1 is being issued primarily to implement administrative changes to the requalification examination program resulting from the amendment to 10 CFR 55 that eliminated the requirement for every licensed operator to pass an NRC-conducted requalification examination as a condition for license renewal. The supplement does not substantially alter either the initial or requalification examination processes and will become effective 30 days after its publication is noticed in the Federal Register. The corporate notification letters issued after the effective date will provide facility licensees with at least 90 days notice that the examinations will be administered in accordance with the revised procedures
International Nuclear Information System (INIS)
Oohashi, Hideaki.
1982-01-01
Purpose: To enable a reactor operator to perform safety and sure inspection for a reactor and take manual start-up operations for the necessary systems at optimum timing with neither misoperation nor misjudging after the occurrence of reactor accidents. Constitution: If a signal judging circuit judges the generation of an accident signal for a reactor, the circuit issues an output signal to start the time counting operation of a time counter thereby inform the elapse of time after the occurrence of the reactor accident. Further, a time signal generated on every predetermined time from the time counter and a process signal indicating the reactor status are logically judged and, if the conditions for taking manual start-up operations, are satisfied, a start-up instruction signal is generated. An information signal is formed depending on the start-up instruction and the content of the start-up instruction is displayed on every predetermined time by the information signal, whereby the operator can perform the manual start-up operations at the optimum timings. (Moriyama, K.)
HP upgrade operational streamlining
Edge, David R.; Emenheiser, Kenneth S.; Hanrahan, William P., III; Mccollums, D.; Seery, Paul J.; Ricklefs, Randall L.
1993-01-01
New computer technology and resources must be successfully integrated into CDSLR station operations to manage new complex operational tracking requirements, support the on site production of new data products, support ongoing station performance improvements, and to support new station communication requirements. The NASA CDSLR Network is in the process of upgrading station computer resources with HP UNIX workstations, designed to automate a wide range of operational station requirements. The primary HP upgrade objective was to relocate computer intensive data system tasks from the controller computer to a new advanced computer environment designed to meet the new data system requirements. The HP UNIX environment supports fully automated real time data communications, data management, data processing, and data quality control. Automated data compression procedures are used to improve the efficiency of station data communications. In addition, the UNIX environment supports a number of semi-automated technical and administrative operational station tasks. The x window user interface generates multiple simultaneous color graphics displays, providing direct operator visibility and control over a wide range of operational station functions.
Wu, L.; Liu, S.; Yang, Yingjie
2016-01-01
Traditional integer order buffer operator is extended to fractional order buffer operator, the corresponding relationship between the weakening buffer operator and the strengthening buffer operator is revealed. Fractional order buffer operator not only can generalize the weakening buffer operator and the strengthening buffer operator, but also realize tiny adjustment of buffer effect. The effectiveness of GM(1,1) with the fractional order buffer operator is validated by six cases.
Automated emergency operating procedures
International Nuclear Information System (INIS)
Perez-Ramirez, G.; Nelson, P.F.
1990-01-01
This paper describes the development of a training tool for the symptom oriented emergency operating procedures used at the Laguna Verde Nuclear Power Plant. EOPs and operator training are intended to assist the operator for managing accident situations. A prototype expert system based on the EOPs has been developed for operator training. The demonstration expert system was developed using a commercial shell. The knowledge base consists of two parts. The specific operator actions to be executed for 5 selected accident sequences and the EOPs steps for the reactor pressure vessel control of the water level, pressure, and power. The knowledge is expressed in the form of IF-THEN production rules. A typical training session will display a set of conditions and will prompt the trainee to indicate the appropriate step to perform. This mode will guide the trainee through selected accident sequences. A second mode of the expert system will prompt the trainee for the current plant conditions and the expert system will respond with the EOPs which are required to be performed under these conditions. This allows the trainee to study What if situations
Operator representations of frames
DEFF Research Database (Denmark)
Christensen, Ole; Hasannasab, Marzieh
2017-01-01
The purpose of this paper is to consider representations of frames {fk}k∈I in a Hilbert space ℋ of the form {fk}k∈I = {Tkf0}k∈I for a linear operator T; here the index set I is either ℤ or ℒ0. While a representation of this form is available under weak conditions on the frame, the analysis...... of the properties of the operator T requires more work. For example it is a delicate issue to obtain a representation with a bounded operator, and the availability of such a representation not only depends on the frame considered as a set, but also on the chosen indexing. Using results from operator theory we show...... that by embedding the Hilbert space ℋ into a larger Hilbert space, we can always represent a frame via iterations of a bounded operator, composed with the orthogonal projection onto ℋ. The paper closes with a discussion of an open problem concerning representations of Gabor frames via iterations of a bounded...
International Nuclear Information System (INIS)
Shimomura, Y.; Huget, M.; Mizoguchi, T.; Murakami, Y.; Polevoi, A.; Shimada, M.; Aymar, R.; Chuyanov, V.; Matsumoto, H.
2001-01-01
ITER is planned to be the first fusion experimental reactor in the world operating for research in physics and engineering. The first 10 years' operation will be devoted primarily to physics issues at low neutron fluence and the following 10 years' operation to engineering testing at higher fluence. ITER can accommodate various plasma configurations and plasma operation modes such as inductive high Q modes, long pulse hybrid modes, non-inductive steady-state modes, with large ranges of plasma current, density, beta and fusion power, and with various heating and current drive methods. This flexibility will provide an advantage for coping with uncertainties in the physics database, in studying burning plasmas, in introducing advanced features and in optimizing the plasma performance for the different programme objectives. Remote sites will be able to participate in the ITER experiment. This concept will provide an advantage not only in operating ITER for 24 hours per day but also in involving the world-wide fusion communities and in promoting scientific competition among the Parties. (author)
International Nuclear Information System (INIS)
1989-06-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. Since all of the data concerning operation of the units are provided by the utility operators less than two weeks after the end of the month, necessary corrections to published information are shown on the ERRATA page. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Amplification of the parametric dynamical Casimir effect via optimal control
Hoeb, Fabian; Angaroni, Fabrizio; Zoller, Jonathan; Calarco, Tommaso; Strini, Giuliano; Montangero, Simone; Benenti, Giuliano
2017-09-01
We introduce different strategies to enhance photon generation in a cavity within the Rabi model in the ultrastrong coupling regime. We show that a bang-bang strategy allows one to enhance the effect up to 1 order of magnitude with respect to simply driving the system in resonance for a fixed time. Moreover, up to about another order of magnitude can be gained by exploiting quantum optimal control strategies. Finally, we show that such optimized protocols are robust with respect to systematic errors and noise, paving the way to future experimental implementations of such strategies.
Parallel plate structures for optical modulation and casimir force measurement
Syed Nawazuddin, M.B.; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Elwenspoek, Michael Curt
2009-01-01
Integrated optical switches using mechano-optical sensing are gaining more attention in many fields due to their fast switching speed, large bandwidth and compact devices. In this paper, a micromachined electrostatically actuated metal plate to sense the evanescent field above the waveguide is
Casimir densities for a boundary in Robertson-Walker spacetime
Energy Technology Data Exchange (ETDEWEB)
Saharian, A.A., E-mail: saharian@ictp.i [Department of Physics, Yerevan State University, 1 Alex Manoogian Street, 0025 Yerevan (Armenia); Setare, M.R., E-mail: rezakord@ipm.i [Department of Science of Bijar, University of Kurdistan, Bijar (Iran, Islamic Republic of)
2010-04-12
For scalar and electromagnetic fields we evaluate the vacuum expectation value of the energy-momentum tensor induced by a curved boundary in the Robertson-Walker spacetime with negative spatial curvature. In order to generate the vacuum densities we use the conformal relation between the Robertson-Walker and Rindler spacetimes and the corresponding results for a plate moving by uniform proper acceleration through the Fulling-Rindler vacuum. For the general case of the scale factor the vacuum energy-momentum tensor is presented as the sum of the boundary free and boundary induced parts.
Casimir densities for a boundary in Robertson-Walker spacetime
International Nuclear Information System (INIS)
Saharian, A.A.; Setare, M.R.
2010-01-01
For scalar and electromagnetic fields we evaluate the vacuum expectation value of the energy-momentum tensor induced by a curved boundary in the Robertson-Walker spacetime with negative spatial curvature. In order to generate the vacuum densities we use the conformal relation between the Robertson-Walker and Rindler spacetimes and the corresponding results for a plate moving by uniform proper acceleration through the Fulling-Rindler vacuum. For the general case of the scale factor the vacuum energy-momentum tensor is presented as the sum of the boundary free and boundary induced parts.
Casimir forces in multilayer magnetodielectrics with both gain and loss
DEFF Research Database (Denmark)
Amooghorban, Ehsan; Wubs, Martijn; Mortensen, N. Asger
2011-01-01
A path-integral approach to the quantization of the electromagnetic field in a linearly amplifying magnetodielectric medium is presented. Two continua of inverted harmonic oscillators are used to describe the polarizability and magnetizability of the amplifying medium. The causal susceptibilities...
The trace identity and the planar Casimir effect
Indian Academy of Sciences (India)
Abstract. The familiar trace identity associated with the scale transformation xµ → x µ = e−λxµ on the Lagrangian density for a noninteracting massive real scalar field in 2 + 1 dimensions is shown to be violated on a single plate on which the Dirichlet boundary condition φ(t, x1, x2 = −a) = 0 is imposed. It is however respected ...
The trace identity and the planar Casimir effect
Indian Academy of Sciences (India)
The familiar trace identity associated with the scale transformation → ′ = - on the Lagrangian density for a noninteracting massive real scalar field in 2 + 1 dimensions is shown to be violated on a single plate on which the Dirichlet boundary condition (, 1, 2 = -) = 0 is imposed. It is however respected ...
Casimir effect for closed cavities with conducting and permeable walls
International Nuclear Information System (INIS)
Ferreira, L.A.; Zimerman, A.H.; Ruggiero, J.R.
1980-01-01
The quantum electromagnetic zero point energy is calculated for rectangular cavities where some of the walls are perfect conductors and the others are made of infinitely permeable materials. It is found that for cubic systems, for some configurations the zero point electromagnetic energy is positive, while in other configurations this zero point energy is negative. The consequences of these results on possible models for the electron are discussed. (Author) [pt
On boson condensation considering a generalized Casimir example
Voigt, K.
1990-12-01
From the concept of generalized condensation [M. Van den Berg, J. T. Lewis, and J. V. Pulè, Helv. Phys. Acta 59, 1271 (1986)] it is known that two critical densities ρc and ρm exist for a free boson gas. Density ρc is the classical one and ρm is the critical density below which there can be no macroscopic occupation of ground state. A free boson gas is studied in a weak external potential which behaves asymptotically like ||x1||α1+||x2||α2+ṡṡṡ +||xd||αd near the origin. It is shown that there are only two possibilities to get ρc<ρm<∞, namely, α1=α2=∞ and d≥3 (this corresponds to Dirichlet boundary conditions), and α1=2 and d≥2 (i.e., a harmonic oscillator).
Casimir Force Contrast Between Amorphous and Crystalline Phases of AIST
Torricelli, Gauthier; van Zwol, Peter J.; Shpak, Olex; Palasantzas, George; Svetovoy, Vitaly B.; Binns, Chris; Kooi, Bart J.; Jost, Peter; Wuttig, Matthias
2012-01-01
Phase change materials (PCMs) can be rapidly and reversibly switched between the amorphous and crystalline state. The structural transformation is accompanied by a significant change of optical and electronic properties rendering PCMs suitable for rewritable optical data storage and non-volatile
Casimir Force Contrast Between Amorphous and Crystalline Phases of AIST
Torrichelli, G.; van Zwol, P.J.; Shpak, O.; Palasantzas, G.; Svetovoy, Vitaly; Binns, C.; Kooi, B.J.; Jost, P.; Wittig, M.
2012-01-01
Phase change materials (PCMs) can be rapidly and reversibly switched between the amorphous and crystalline state. The structural transformation is accompanied by a signifi cant change of optical and electronic properties rendering PCMs suitable for rewritable optical data storage and nonvolatile
Symmetries and casimir of an extended classical long wave system
Indian Academy of Sciences (India)
In this paper, we derive Lie point, generalized, master and time-dependent symmetries of a dispersionless equation, which is an extension of a classical long wave system. This equation also admits an infinite-dimensional Lie algebraic structure of Virasoro-type, as in the dispersive integrable systems. We discuss the ...
Global consequences of a local Casimir force : Adhered cantilever
Svetovoy, V. B.; Melenev, A. E.; Lokhanin, M. V.; Palasantzas, G.
2017-01-01
Although stiction is a cumbersome problem for microsystems, it stimulates investigations of surface adhesion. In fact, the shape of an adhered cantilever carries information of the adhesion energy that locks one end to the substrate. We demonstrate here that the system is also sensitive to the
Symmetries and casimir of an extended classical long wave system
Indian Academy of Sciences (India)
... has strong physical reasons and rich mathematical structures. Also, it is of recent interest to obtain many integrable systems from Benney system under various reductions and the study of these reduced systems also assumes significance [6,7]. It is well known that Benney system [1] ut = uux + ghx − uy. ∫ h. 0 ux dy, ht =.
Banach, S
1987-01-01
This classic work by the late Stefan Banach has been translated into English so as to reach a yet wider audience. It contains the basics of the algebra of operators, concentrating on the study of linear operators, which corresponds to that of the linear forms a1x1 + a2x2 + ... + anxn of algebra.The book gathers results concerning linear operators defined in general spaces of a certain kind, principally in Banach spaces, examples of which are: the space of continuous functions, that of the pth-power-summable functions, Hilbert space, etc. The general theorems are interpreted in various mathematical areas, such as group theory, differential equations, integral equations, equations with infinitely many unknowns, functions of a real variable, summation methods and orthogonal series.A new fifty-page section (``Some Aspects of the Present Theory of Banach Spaces'''') complements this important monograph.
International Nuclear Information System (INIS)
1989-08-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
International Nuclear Information System (INIS)
1990-01-01
The US Nuclear Regulatory Commission's monthly LICENSED OPERATING REACTORS Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
International Nuclear Information System (INIS)
Hartfield, R.A.
1990-03-01
The US Nuclear Regulatory Commission's monthly Licensed Operating Reactors Status Summary Report provides data on the operation of nuclear units as timely and accurately as possible. This information is collected by the Office of Information Resources Management, from the Headquarters Staff of NRC's Office of Inspection and Enforcement, from NRC's Regional Offices, and from utilities. This report is divided into three sections: the first contains monthly highlights and statistics for commercial operating units, and errata from previously reported data; the second is a compilation of detailed information on each unit, provided by NRC Regional Offices, IE Headquarters and the Utilities; and the third section is an appendix for miscellaneous information such as spent fuel storage capability, reactor years of experience and non-power reactors in the United States
Operations management for construction
March, Chris
2009-01-01
Students studying construction management and related subjects need to have a broad understanding of the major aspects of controlling the building processes. Operations Management for Construction is one of three textbooks (Business Organisation, Operations Management and Finance Control) written to systematically cover the field. Focusing on construction sites and operations which are challenging to run, Chris March explores issues such as the setting up of the site, the deciding of the methodology of construction, and the sequence of work and resourcing. As changing and increasing regulations affect the way sites are managed, he also considers the issues and methods of successful administering, safety, quality and environment. Finally, the contractor's responsibility to the environment, including relationships with third parties, selection of materials, waste management and sustainability is discussed. Chris March has a wealth of practical experience in the construction industry, as well as considerable exp...
International Nuclear Information System (INIS)
Yuzhakov, A.Yu.
2010-01-01
The author reports on the application of full-scale simulators for training and maintaining proficiency of unit control room operators that is an essential element of Russian NPPs personnel education system. The existing simulators for the unit control room operating personnel are listed. The integrated approach to developing and maintaining the training hardware is described. The integrated approach is being implemented on the basis of observance of the existing requirements to training hardware, improvement of regulations, control from a single centre responsible for the provision of support to the activities, inclusion into the plans of simulators for development of skills for operating control over equipment and systems, as well as control from local boards [ru
The operation and maintenance manual
International Nuclear Information System (INIS)
Klein, W.; Krotil, H.; Stoll, A.
1975-01-01
The Operating Manual is one of many technical documents which the nuclear power plant operator needs for ensuring safe operation. For the operating staff, however, there is only one document, namely the Operating Manual. It contains, appropriately arranged, the necessary system and other diagrams, drawings, lists, licensing documents and similar material, which are necessary for understanding the design, for testing, for obtaining the operating licence and for the operation of individual systems and of the entire plant. (orig./RW) [de
International Nuclear Information System (INIS)
Schardt, John
2007-01-01
GNF's latest generation fuel product, GNF2, is designed to deliver improved nuclear efficiency, higher bundle and cycle energy capability, and more operational flexibility. But along with high performance, our customers face a growing need for absolute fuel reliability. This is driven by a general sense in the industry that LWR fuel reliability has plateaued. Too many plants are operating with fuel leakers, and the impact on plant operations and operator focus is unacceptable. The industry has responded by implementing an INPO-coordinated program aimed at achieving leaker-free reliability by 2010. One focus area of the program is the relationship between fuel performance (i.e., duty) and reliability. The industry recognizes that the right balance between performance and problem-free fuel reliability is critical. In the development of GNF2, GNF understood the requirement for a balanced solution and utilized a product development and introduction strategy that specifically addressed reliability: evolutionary design features supported by an extensive experience base; thoroughly tested components; and defense-in-depth mitigation of all identified failure mechanisms. The final proof test that the balance has been achieved is the application of the design, initially through lead use assemblies (LUAs), in a variety of plants that reflect the diversity of the BWR fleet. Regular detailed surveillance of these bundles provides the verification that the proper balance between performance and reliability has been achieved. GNF currently has GNF2 lead use assemblies operating in five plants. Included are plants that have implemented extended power up-rates, plants on one and two-year operating cycles, and plants with and without NobleChem TM and zinc injection. The leading plant has undergone three pool-side inspections outages to date. This paper reviews the actions taken to insure GNF2's reliability, and the lead use assembly surveillance data accumulated to date to validate
Alkaline battery operational methodology
Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael
2016-08-16
Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.
Waddell, Patrick G.; Davidson, Jacqueline A.
2002-02-01
The SOFIA Airborne Observatory will operate a 2.5 m aperture telescope with the goal of obtaining over 960 successful science hours per year at a nominal altitude of 12.5 km and covering a wavelength range from 0.3 mm to 1.6 mm. The observatory platform is comprised of a Boeing 747SP with numerous significant modifications. The ground and flight mission operations architectures and plans are tailored to keep the telescope emissivity low and achieve high observing efficiency.
Piping engineering and operation
International Nuclear Information System (INIS)
1993-01-01
The conference 'Piping Engineering and Operation' was organized by the Institution of Mechanical Engineers in November/December 1993 to follow on from similar successful events of 1985 and 1989, which were attended by representatives from all sectors of the piping industry. Development of engineering and operation of piping systems in all aspects, including non-metallic materials, are highlighted. The range of issues covered represents a balance between current practices and implementation of future international standards. Twenty papers are printed. Two, which are concerned with pressurized pipes or steam lines in the nuclear industry, are indexed separately. (Author)
Ball, Joseph A; Helton, JWilliam; Rodman, Leiba; Spitkovsky, Iiya
2010-01-01
This is the first volume of a collection of original and review articles on recent advances and new directions in a multifaceted and interconnected area of mathematics and its applications. It encompasses many topics in theoretical developments in operator theory and its diverse applications in applied mathematics, physics, engineering, and other disciplines. The purpose is to bring in one volume many important original results of cutting edge research as well as authoritative review of recent achievements, challenges, and future directions in the area of operator theory and its applications.
Seminar 1. Joint Military Operations. Application of the Operational Reserve
National Research Council Canada - National Science Library
Copp, A
1997-01-01
.... As a means of achieving decisive effect at the operational level of war, the operational reserve should be considered an operational function and should be addressed as both a planning element...
Operational Design for Peace Enforcement: Lessons for the Operational Staff
National Research Council Canada - National Science Library
Neumann, Michael
2004-01-01
U.S. involvement in Somalia serves as a useful case study of the unique challenges an operational staff may face when applying operational design to the planning and execution of a peace enforcement operation. U.S...
On commuting operator exponentials, II
Indian Academy of Sciences (India)
where N is an unbounded normal operator and M is a bounded normal operator in the. Hilbert space. Keywords. Self-adjoint and normal operator; commuting normal operator exponent- ials; Borel functional calculus. 1. Introduction. Let E be a complex Hilbert space and let B(E) be the algebra of bounded linear operators.
Scheduling in the operating theatre.
Rose, M. B.; Davies, D. C.
1984-01-01
The effect of scheduling on the use of operating theatre time has been studied. Scheduling involved determining the average length of common operations and fitting them into the calculated available operating time. The technique has been shown to reduce significantly the variation in length of operating sessions, and it ensures the best use of available operating time.
Monitoring of operating processes
International Nuclear Information System (INIS)
Barry, R.F.
1981-01-01
Apparatus is described for monitoring the processes of a nuclear reactor to detect off-normal operation of any process and for testing the monitoring apparatus. The processes are evaluated by response to their paramters, such as temperature, pressure, etc. The apparatus includes a pair of monitoring paths or signal processing units. Each unit includes facilities for receiving on a time-sharing basis, a status binary word made up of digits each indicating the status of a process, whether normal or off-normal, and test-signal binary words simulating the status binary words. The status words and test words are processed in succession during successive cycles. During each cycle, the two units receive the same status word and the same test word. The test words simulate the status words both when they indicate normal operation and when they indicate off-normal operation. Each signal-processing unit includes a pair of memories. Each memory receives a status word or a test word, as the case may be, and converts the received word into a converted status word or a converted test word. The memories of each monitoring unit operate into a non-coincidence which signals non-coincidence of the converted word out of one memory of a signal-processing unit not identical to the converted word of the other memory of the same unit
DEFF Research Database (Denmark)
Slepniov, Dmitrij; Wæhrens, Brian Vejrum; Gubi, Ebbe
2013-01-01
Companies are actively seeking competitive advantage through their choice of location and ownership of operations. The purpose of this chapter is to uncover hidden effects of this development and propose how companies can respond to them. The chapter draws on a case study of a Danish industrial e...... of analysis and involving temporal adaptations. In terms of managerial implications, the study provides managers with lessons for designing a robust system of globally dispersed operations.......Companies are actively seeking competitive advantage through their choice of location and ownership of operations. The purpose of this chapter is to uncover hidden effects of this development and propose how companies can respond to them. The chapter draws on a case study of a Danish industrial...... equipment firm and describes how its operations configuration has been changing over time. The chapter identifies the key determinants of this change and uncovers some of its hidden effects. The chapter closes with propositions for how to respond to these effects through the development of a distinct...
Rocco, David A.
1994-01-01
Redefining the approach and philosophy that operations management uses to define, develop, and implement space missions will be a central element in achieving high efficiency mission operations for the future. The goal of a cost effective space operations program cannot be realized if the attitudes and methodologies we currently employ to plan, develop, and manage space missions do not change. A management philosophy that is in synch with the environment in terms of budget, technology, and science objectives must be developed. Changing our basic perception of mission operations will require a shift in the way we view the mission. This requires a transition from current practices of viewing the mission as a unique end product, to a 'mission development concept' built on the visualization of the end-to-end mission. To achieve this change we must define realistic mission success criteria and develop pragmatic approaches to achieve our goals. Custom mission development for all but the largest and most unique programs is not practical in the current budget environment, and we simply do not have the resources to implement all of our planned science programs. We need to shift our management focus to allow us the opportunity make use of methodologies and approaches which are based on common building blocks that can be utilized in the space, ground, and mission unique segments of all missions.
Improved chain control operations.
2010-01-01
In California, field maintenance personnel use turntable signs to advise motorists of chain control conditions on rural : highways and freeways. To do this an operator has to park, exit the vehicle, turn the sign on the shoulder and then : walk acros...
Czech Academy of Sciences Publication Activity Database
Blanc, D.; Markl, Martin
2003-01-01
Roč. 245, č. 1 (2003), s. 1-29 ISSN 0025-5874 R&D Projects: GA AV ČR IAA1019203 Institutional research plan: CEZ:AV0Z1019905; CEZ:AV0Z1019905 Keywords : higher homotopy operation * W-construction * polyhedron Subject RIV: BA - General Mathematics Impact factor: 0.678, year: 2003
Simplifying Operational Design
2012-05-01
Terraine’s spider web metaphor reflects the complex, highly interactive operating environment that appropriately should be analyzed through a...describing it as, “not prescriptive or a checklist , design is based on critical thinking, conceptual planning, visualization, emergence of a hypothesis
Operator/contractor relationships
International Nuclear Information System (INIS)
Smith, J.R.; Kidwell, C.K.; Unger, V.E.; Fercho, E.; Helmer, C.M.
1992-01-01
In May 1988, Shell Western E and P Inc. (SWEPI) and partners Elf Aquitaine Petroleum and Conoco Inc. signed a letter of intent with Canadian Marine Drilling Ltd. (Canmar) for provision of exploratory drilling and marine services on leases in OCS Lease Sale 109 in the Chukchi Sea, Alaska. The 5450 blocks offered in the remote sale area west of Point Barrow ranged from 3 to 240 miles (5 to 380 km) offshore in water depths from 26 to 263 feet (8 to 80 m). The principal interest tracts were at least 75 miles (120 km) offshore and north of 70 degrees N latitude. The remoteness and total lack of any oilfield infrastructure required considerable planning and coordination between Operator and Contractor in order to carry out the three-year drilling program efficiently and safely in an environmentally harsh and, at the same time, sensitive area. SWEPI and Canmar developed a close working relationship from the start of the project through a number of participative approaches to the problems that had to be solved. This paper reports that these included strong reliance on operational planning meetings, post-season analyses, and an overall emphasis on the teamwork required of both parties to carry out the first-ever drilling program in the Chukchi Sea. This approach led to a very successful operation for both parties and emphasizes the positive benefits achievable when Operator and Contractor work as a team
Resilient Grid Operational Strategies
Energy Technology Data Exchange (ETDEWEB)
Pasqualini, Donatella [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-03-01
Extreme weather-related disturbances, such as hurricanes, are a leading cause of grid outages historically. Although physical asset hardening is perhaps the most common way to mitigate the impacts of severe weather, operational strategies may be deployed to limit the extent of societal and economic losses associated with weather-related physical damage.1 The purpose of this study is to examine bulk power-system operational strategies that can be deployed to mitigate the impact of severe weather disruptions caused by hurricanes, thereby increasing grid resilience to maintain continuity of critical infrastructure during extreme weather. To estimate the impacts of resilient grid operational strategies, Los Alamos National Laboratory (LANL) developed a framework for hurricane probabilistic risk analysis (PRA). The probabilistic nature of this framework allows us to estimate the probability distribution of likely impacts, as opposed to the worst-case impacts. The project scope does not include strategies that are not operations related, such as transmission system hardening (e.g., undergrounding, transmission tower reinforcement and substation flood protection) and solutions in the distribution network.
Electromagnetically Operated Counter
Goldberg, H D; Goldberg, M I
1951-12-18
An electromagnetically operated counter wherein signals to be counted are applied to cause stepwise rotation of a rotatable element which is connected to a suitable register. The mechanism involved consists of a rotatable armature having three spaced cores of magnetic material and a pair of diametrically opposed electromagnets with a suitable pulsing circuit to actuate the magnets.
Operation for gigantincisionalhernie
DEFF Research Database (Denmark)
Eriksson, Axelina; Krag, Christen; Jørgensen, Lars Nannestad
2014-01-01
level evidence. Mesh placement is possible onlay, inlay, sublay or intraperitoneal. These operations are most often performed as open procedures, or in combination with endoscopic techniques. These procedures should be centralized to few centers to improve quality and allow robust research....
McKim, Vicky L
2017-06-01
In the world of risk management, which encompasses the business continuity disciplines, many types of risk require evaluation. Financial risk is most often the primary focus, followed by product and market risks. Another critical area, which typically lacks a thorough review or may be overlooked, is operational risk. This category encompasses many risk exposure types including those around building structures and systems, environmental issues, nature, neighbours, clients, regulatory compliance, network, data security and so on. At times, insurance carriers will assess internal hazards, but seldom do these assessments include more than a cursory look at other types of operational risk. In heavily regulated environments, risk assessments are required but may not always include thorough assessments of operational exposures. Vulnerabilities may linger or go unnoticed, only to become the catalyst for a business disruption at a later time, some of which are so severe that business recovery becomes nearly impossible. Businesses may suffer loss of clients as the result of a prolonged disruption of services. Comprehensive operational risk assessments can assist in identifying such vulnerabilities, exposures and threats so that the risk can be minimised or removed. This paper lays out how an assessment of this type can be successfully conducted.
Energy Technology Data Exchange (ETDEWEB)
Jan Berkow; Larry Banta
2003-07-29
The Intelligent Potroom Operation project focuses on maximizing the performance of an aluminum smelter by innovating components for an intelligent manufacturing system. The Intelligent Potroom Advisor (IPA) monitors process data to identify reduction cells exhibiting behaviors that require immediate attention. It then advises operational personnel on those heuristic-based actions to bring the cell back to an optimal operating state in order to reduce the duration and frequency of substandard reduction cell performance referred to as ''Off-Peak Modes'' (OPMs). Techniques developed to identify cells exhibiting OPMs include the use of a finite element model-based cell state estimator for defining the cell's current operating state via advanced cell noise analyses. In addition, rule induction was also employed to identify statistically significant complex behaviors that occur prior to OPMs. The intelligent manufacturing system design, concepts and formalisms developed in this project w ere used as a basis for an intelligent manufacturing system design. Future research will incorporate an adaptive component to automate continuous process improvement, a technology platform with the potential to improve process performance in many of the other Industries of the Future applications as well.
Mullender, Sape J.
1987-01-01
In the past five years, distributed operating systems research has gone through a consolidation phase. On a large number of design issues there is now considerable consensus between different research groups. In this paper, an overview of recent research in distributed systems is given. In turn, the
2015-03-01
wine warfare NCC naval component commander NFC numbered fleet commander NM nautical mile NMP Navy mission planner NOP Navy...Planner (RASP) is another example of an operational planning tool. RASP focuses on fuel conservation as it optimizes schedules for CLF 5 ships. Brown
Operations and Modeling Analysis
Ebeling, Charles
2005-01-01
The Reliability and Maintainability Analysis Tool (RMAT) provides NASA the capability to estimate reliability and maintainability (R&M) parameters and operational support requirements for proposed space vehicles based upon relationships established from both aircraft and Shuttle R&M data. RMAT has matured both in its underlying database and in its level of sophistication in extrapolating this historical data to satisfy proposed mission requirements, maintenance concepts and policies, and type of vehicle (i.e. ranging from aircraft like to shuttle like). However, a companion analyses tool, the Logistics Cost Model (LCM) has not reached the same level of maturity as RMAT due, in large part, to nonexistent or outdated cost estimating relationships and underlying cost databases, and it's almost exclusive dependence on Shuttle operations and logistics cost input parameters. As a result, the full capability of the RMAT/LCM suite of analysis tools to take a conceptual vehicle and derive its operations and support requirements along with the resulting operating and support costs has not been realized.
Dam safety operating guidelines
International Nuclear Information System (INIS)
Elsayed, E.; Leung, T.; Kirkham, A.; Lum, D.
1990-01-01
As part of Ontario Hydro's dam structure assessment program, the hydraulic design review of several river systems has revealed that many existing dam sites, under current operating procedures, would not have sufficient discharge capacity to pass the Inflow Design Flood (IDF) without compromising the integrity of the associated structures. Typical mitigative measures usually considered in dealing with these dam sites include structural alterations, emergency action plans and/or special operating procedures designed for extreme floods. A pilot study was carried out for the Madawaska River system in eastern Ontario, which has seven Ontario Hydro dam sites in series, to develop and evaluate the effectiveness of the Dam Safety Operating Guidelines (DSOG). The DSOG consist of two components: the flood routing schedules and the minimum discharge schedules, the former of which would apply in the case of severe spring flood conditions when the maximum observed snowpack water content and the forecast rainfall depth exceed threshold values. The flood routing schedules would identify to the operator the optimal timing and/or extent of utilizing the discharge facilities at each dam site to minimize the potential for dam failures cased by overtopping anywhere in the system. It was found that the DSOG reduced the number of structures overtopped during probable maximum flood from thirteen to four, while the number of structures that could fail would be reduced from seven to two. 8 refs., 4 figs., 3 tabs
African Journals Online (AJOL)
Administrator
OPERATION ZITADELLE (KURSK),. 5-14 JULY 1943, A CASE STUDY. Col (Dr) James Jacobs. Resident Historian. South African War College. Introduction. In wartime military organisations function in a dangerous and complex environment. Doctrines are designed to ensure standardisation of thinking about military conflict ...
Invariant differential operators
Dobrev, Vladimir K
2016-01-01
With applications in quantum field theory, elementary particle physics and general relativity, this two-volume work studies invariance of differential operators under Lie algebras, quantum groups, superalgebras including infinite-dimensional cases, Schrödinger algebras, applications to holography. This first volume covers the general aspects of Lie algebras and group theory.
Space Operations Learning Center
Lui, Ben; Milner, Barbara; Binebrink, Dan; Kuok, Heng
2012-01-01
The Space Operations Learning Center (SOLC) is a tool that provides an online learning environment where students can learn science, technology, engineering, and mathematics (STEM) through a series of training modules. SOLC is also an effective media for NASA to showcase its contributions to the general public. SOLC is a Web-based environment with a learning platform for students to understand STEM through interactive modules in various engineering topics. SOLC is unique in its approach to develop learning materials to teach schoolaged students the basic concepts of space operations. SOLC utilizes the latest Web and software technologies to present this educational content in a fun and engaging way for all grade levels. SOLC uses animations, streaming video, cartoon characters, audio narration, interactive games and more to deliver educational concepts. The Web portal organizes all of these training modules in an easily accessible way for visitors worldwide. SOLC provides multiple training modules on various topics. At the time of this reporting, seven modules have been developed: Space Communication, Flight Dynamics, Information Processing, Mission Operations, Kids Zone 1, Kids Zone 2, and Save The Forest. For the first four modules, each contains three components: Flight Training, Flight License, and Fly It! Kids Zone 1 and 2 include a number of educational videos and games designed specifically for grades K-6. Save The Forest is a space operations mission with four simulations and activities to complete, optimized for new touch screen technology. The Kids Zone 1 module has recently been ported to Facebook to attract wider audience.
Operant Conditioning - Token Economy.
Montgomery, Jacqueline; McBurney, Raymond D.
Described is an Operant Conditioning-Token Economy Program, teaching patients to be responsible for their own behavior, to make choices, and to be motivated to change. The program was instigated with mentally ill patients in a state hospital and was later used with institutionalized mentally handicapped groups. After two years, only four of the…
Teachers and Operant Conditioning.
Frey, Sherman
A survey was conducted of 406 elementary, middle, and secondary school teachers to determine their understanding, acceptance, and use of the principle of operant conditioning. The treatment of data was by percent and chi square analysis primarily according to sex, experience, degree, and position. Subjects reported that a) they believed that the…
Unit 34, CCTP; Pitts, Teresa A.
1998-01-01
This unit describes types, example uses and implementation of different overlay operations. Using commands in ESRI’s Arc/Info, it summarizes necessary pre-overlay and overlay tasks in an example application in which locations for Gypsy Moth traps must be determined.
DSMS science operations concept
Connally, M. J.; Kuiper, T. B.
2001-01-01
The Deep Space Mission System (DSMS) Science Operations Concept describes the vision for enabling the use of the DSMS, particularly the Deep Space Network (DSN) for direct science observations in the areas of radio astronomy, planetary radar, radio science and VLBI.
Splunk operational intelligence cookbook
Diakun, Josh; Mock, Derek
2014-01-01
This book is intended for users of all levels who are looking to leverage the Splunk Enterprise platform as a valuable operational intelligence tool. The recipes provided in this book will appeal to individuals from all facets of a business - IT, Security, Product, Marketing, and many more!
Indian Academy of Sciences (India)
Linux Distributions. Linux per se refers only to the kernel of the operating system. A full fledged Unix system however requires a set of applications and support software that make the system user friendly. Hundreds of programmers around the world ,have contributed to bring the Linux system to its current state of robustness.
ATC operational error analysis.
1972-01-01
The primary causes of operational errors are discussed and the effects of these errors on an ATC system's performance are described. No attempt is made to specify possible error models for the spectrum of blunders that can occur although previous res...
Concept of Operations: Essence
Energy Technology Data Exchange (ETDEWEB)
Hutton, William J.
2014-04-01
This concept of operations is designed to give the reader a brief overview of the National Rural Electric Cooperative Association’s Essence project and a description of the Essence device design. The data collected by the device, how the data are used, and how the data are protected are also discussed in this document.
Basic Water Treatment Operation.
Ontario Ministry of the Environment, Toronto.
This manual was developed for use at workshops designed to introduce the fundamentals of water treatment plant operations. The course consists of lecture-discussions and hands-on activities. Each of the fourteen lessons in this document has clearly stated behavioral objectives to tell the trainee what he should know or do after completing that…
Operational Amplifer Integrator
van Tuijl, Adrianus Johannes Maria
2003-01-01
An integrator circuit comprises an operational amplifier which has a transistor stage (1) with an input terminal (4) and an output terminal (3), a feedback capacitor (2) connected between the input terminal (4) and the output terminal (3), and a resistor (5) connected to the input terminal (4), and
Underground mining operation supports
Energy Technology Data Exchange (ETDEWEB)
Khusid, M.B.; Kozel, A.M.
1980-12-10
Underground mining operation supports include the supporting layer surrounded by a cylindrical jacket of cemented rock. To decrease the loss of support material due to the decreasing rock pressure on the supporting layer, the cylindrical jacket of cemented rock has an uncemented layer inside, dividing it into 2 concentric cylindrical parts.
Almost periodic Schroedinger operators
International Nuclear Information System (INIS)
Bellissard, J.; Lima, R.
1984-01-01
These lectures are devoted to recent developments in the theory of almost-periodic Schroedinger Operators. We specially describe the algebraic point of view, with applications to gap-labelling theorems. Particular models are also presented which exhibit various spectral properties. (orig.)
Operational Area Environmental Evaluations
Energy Technology Data Exchange (ETDEWEB)
Bailey-White, Brenda Eileen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nagy, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wagner, Katrina Marie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Goodman, Thomas Richard [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Herring, Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Catechis, Christopher S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kinghorn, Aubrianna Nicole [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Ellie [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Barthel, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casaus, Benito [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2017-08-01
The Operational Area Environmental Evaluation update provides a description of activities that have the potential to adversely affect natural and cultural resources, including soil, air, water, biological, ecological, and historical resources. The environmental sensitivity of an area is evaluated and summarized, which may facilitate informed management decisions as to where development may be prohibited, restricted, or subject to additional requirements.
Effectiveness of operation tools developed by KEKB operators
International Nuclear Information System (INIS)
Sugino, K.; Satoh, Y.; Kitabayashi, T.
2004-01-01
The main tasks of KEKB (High Energy Accelerator Research Organization B-physics) operators are beam tuning and injection, operation logging, monitoring of accelerator conditions and safety management. New beam tuning methods are frequently applied to KEKB in order to accomplish high luminosity. In such a situation, various operation tools have been developed by the operators to realize efficient operation. In this paper, we describe effectiveness of tools developed by the operators. (author)
International Nuclear Information System (INIS)
Nos, V.; Faig, J.; Plesa, P.; Delgado, J. L.
2000-01-01
The systematic approach to training is internationally accepted as the best method to achieve and maintain the qualification and competence of power plant personnel and to guarantee the quality of their training. Following the recommendations and guidelines of international organisations competent in the field, TECNATOM SA has developed projects based on the systematic approach to training for all Spanish nuclear power plants. One of the latest projects was the systematic approach to training developed for the operation personnel of ASCO Nuclear Power Plant. In this case, certain results of the Probabilistic Safety Analysis (PSA) which complement the systematic safety and reliability criteria of the systematic approach to training process have been incorporated in the traditional processes of work and task analysis and training plan design. This incorporation provides the training manager with additional criteria based not only on safety aspects obtained through the statistical treatment of considerations of skilled technical personnel (operators, operation chief supervisors, etc), but also on the independent criterion of the PSA. The inclusion of this approach basically affects all systematics in two of its stages: During the selection process of operating practices in SMR or SGI, the possible scenarios have been associated with all those situations where human actions which lead to an initiating event or human actions to mitigate an initiating event, may take place, as defined in the PSA. During the scenario development process, the instruments involved in the performance of human actions which originate or mitigate an event taking place have been identified. This pakes it possible to reconcile the scenario event sequence with the sequence considered in the PSA study, as the most likely to provoke a more serious accident. The incorporation of these PSA results contributes to the strengthening of safety aspects in training in an objective way, and confirms that
Cohering power of quantum operations
Energy Technology Data Exchange (ETDEWEB)
Bu, Kaifeng, E-mail: bkf@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China); Kumar, Asutosh, E-mail: asukumar@hri.res.in [Harish-Chandra Research Institute, Chhatnag Road, Jhunsi, Allahabad 211019 (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094 (India); Zhang, Lin, E-mail: linyz@zju.edu.cn [Institute of Mathematics, Hangzhou Dianzi University, Hangzhou 310018 (China); Wu, Junde, E-mail: wjd@zju.edu.cn [School of Mathematical Sciences, Zhejiang University, Hangzhou 310027 (China)
2017-05-18
Highlights: • Quantum coherence. • Cohering power: production of quantum coherence by quantum operations. • Study of cohering power and generalized cohering power, and their comparison for differentmeasures of quantum coherence. • Operational interpretation of cohering power. • Bound on cohering power of a generic quantum operation. - Abstract: Quantum coherence and entanglement, which play a crucial role in quantum information processing tasks, are usually fragile under decoherence. Therefore, the production of quantum coherence by quantum operations is important to preserve quantum correlations including entanglement. In this paper, we study cohering power–the ability of quantum operations to produce coherence. First, we provide an operational interpretation of cohering power. Then, we decompose a generic quantum operation into three basic operations, namely, unitary, appending and dismissal operations, and show that the cohering power of any quantum operation is upper bounded by the corresponding unitary operation. Furthermore, we compare cohering power and generalized cohering power of quantum operations for different measures of coherence.
Regulations for RA reactor operation
International Nuclear Information System (INIS)
1980-09-01
Regulations for RA reactor operation are written in accordance with the legal regulations defined by the Law about radiation protection and related legal acts, as well as technical standards according to the IAEA recommendations. The contents of this book include: fundamental data about the reactor; legal regulations for reactor operation; organizational scheme for reactor operation; general and detailed instructions for operation, behaviour in the reactor building, performing experiments; operating rules for operation under steady state and accidental conditions [sr
Density operators in quantum mechanics
International Nuclear Information System (INIS)
Burzynski, A.
1979-01-01
A brief discussion and resume of density operator formalism in the way it occurs in modern physics (in quantum optics, quantum statistical physics, quantum theory of radiation) is presented. Particularly we emphasize the projection operator method, application of spectral theorems and superoperators formalism in operator Hilbert spaces (Hilbert-Schmidt type). The paper includes an appendix on direct sums and direct products of spaces and operators, and problems of reducibility for operator class by using the projection operators. (author)
Weakly compact operators and interpolation
Maligranda, Lech
1992-01-01
The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. In this survey, we have collected and ordered some of this (partly very new) knowledge. We have also included some comments, remarks and examples. The class of weakly compact operators is, as well as the class of compact operators, a fundamental operator ideal. They were investigated strongly in the last twenty years. I...
Multinational Operations: A Selected Bibliography
National Research Council Canada - National Science Library
2001-01-01
.... Compiled to support the curriculum's Multinational Operations AYO2 special theme, the main part of the bibliography focuses on the special challenges of multinational operations such as command...
International Nuclear Information System (INIS)
1973-01-01
The NOAA Fleet Operations Report 1973 was developed to provide a summary of project accomplishments during calendar year 1973. The report was prepared from season, cruise and special reports submitted by ships of the fleet. Centralized management of the NOAA Fleet was finalized by changing the operational control of the National Marine Fisheries Service (NMFS) Ships DAVID STARR JORDAN (FRS 44), TOWNSEND CROMWELL (FRS 43) and MURRE II (FRV 63) from NMFS to the National Ocean Survey on July 1, 1973. Throughout the year, ships routinely collected and transmitted weather data. Similarly, as NOAA participants in the Integrated Global Ocean Station System (IGOSS) service program, XBT observations were taken and either radioed or submitted in log form via mail. In addition, particulate and radionuclide samples were taken in cooperation with the Atomic Energy Commission, sediment samples were obtained for the Smithsonian Institution and observations were made of marine mammals
International Nuclear Information System (INIS)
Anon.
1985-01-01
This book presents the proceedings of a conference dedicated to the design and operation of pipework in all its aspects, involving both metallic and non-metallic materials. Topics considered include a study of single mitre pipe bends using the finite element method; tests to failure of GRP pipe bends under in-plane flexural loading; finite element stress analysis of an equal diameter branch pipe intersection subjected to internal pressure and in-plane moment loadings; finite element stress analysis of extruded outlet tee junctions; design of pipework on the British PWR; a review of advanced remanent life methods for pipes operating in the creep range; pipe whip analysis and design; damping values for piping systems; pipework snubbers based on electro-rheological fluids; and the seismic design of piping systems in the flexible range
Psychostimulants and military operations.
Eliyahu, Uri; Berlin, Shai; Hadad, Eran; Heled, Yuval; Moran, Daniel S
2007-04-01
Sleep-deprived individuals appear to have decreased psychological and physical capabilities. Studies have shown how major psychological aspects, such as alertness, complex mental performance, and memory, are strongly affected by sleep deprivation. Military use of psychostimulants dates back many years, especially in units that operate over long hours and deprive soldiers of sleep. During prolonged military operations, pilots are regularly kept awake for hours and days without fulfilling their biological sleep requirements. This consequently affects their natural circadian rhythm. This article deals with both the benefits and the side effects of two kinds of psychostimulants, namely, dextroamphetamine, which is more popular and is most widely used, and modafinil, which is a relatively newer type. There is growing evidence that modafinil has fewer side effects, in comparison with its predecessor dextroamphetamine, while still maintaining all of the latter's beneficial characteristics.
Financing Canadian international operations
International Nuclear Information System (INIS)
Beagle, G.
1996-01-01
A primer on financing international operations by Canadian corporations was provided. Factors affecting the availability to project finance (location, political risk), the various forms of financing (debt, equity, and combinations), the main sources of government backed financing to corporations (the International Finance Corporation) (IFC), the European Bank for Reconstruction and Development (EBRD), the Asian Development Bank (ADB), the Overseas Property Insurance Corporation (OPIC), government or agency guarantees, political risk coverage, the use of offshore financial centres, and the where, when and how these various organizations operate, were reviewed. Examples of all of the above, taken from the experiences of Canadian Occidental Petroleum of Calgary in the U.S., in South America, in the Middle and Far East, and in Kazakhstan, were used as illustrations. figs
Hurricane slams gulf operations
International Nuclear Information System (INIS)
Anon.
1992-01-01
This paper reports that reports of damage by Hurricane Andrew escalated last week as operators stepped up inspections of oil and gas installations in the Gulf of Mexico. By midweek, companies operating in the gulf and South Louisiana were beginning to agree that earlier assessments of damage only scratched the surface. Damage reports included scores of lost, toppled, or crippled platforms, pipeline ruptures, and oil slicks. By midweek the U.S. coast Guard had received reports of 79 oil spills. Even platforms capable of resuming production in some instances were begin curtailed because of damaged pipelines. Offshore service companies the another 2-4 weeks could be needed to fully assess Andrew's wrath. Lack of personnel and equipment was slowing damage assessment and repair
ATLAS IBL operational experience
AUTHOR|(INSPIRE)INSPIRE-00237659; The ATLAS collaboration
2016-01-01
The Insertable B-Layer (IBL) is the inner most pixel layer in the ATLAS experiment, which was installed at 3.3 cm radius from the beam axis in 2014 to improve the tracking performance. To cope with the high radiation and hit occupancy due to proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed for the IBL. After the long shut-down period over 2013 and 2014, the ATLAS experiment started data-taking in May 2015 for Run-2 of the Large Hadron Collider (LHC). The IBL has been operated successfully since the beginning of Run-2 and shows excellent performance with the low dead module fraction, high data-taking efficiency and improved tracking capability. The experience and challenges in the operation of the IBL is described as well as its performance.
Operational discipline and microenterprises
Directory of Open Access Journals (Sweden)
Francisca Rosales Gómez
2015-06-01
Full Text Available The aim of this study is to identify the elements of the operational Discipline in the business of micro-enterprises in Coatzacoalcos, Mexico. For the analysis an instrument is designed and applied to 20 companies which fulfill the suggested recommendations in research such as caution in the use of hazardous materials, use of equipment with simple specifications and easily accessible to employees, monitoring of some standard to identify risks, good environmental management, among others. We conclude that despite the findings in the application of the methodology of Operational Discipline, it is generally suffers from many important practices, and can be considered as construction companies of the city of Coatzacoalcos no mandatory environmental care this activity.
International Peacekeeping Operations
2017-01-01
This article takes stock of some of the important contributions to the study of peacekeeping (PK). Two key topics stand out: peacekeeping burden sharing and mission effectiveness. For burden sharing, the theoretical foundation is the private provision of public goods and joint products. Implications for burden sharing differ whether financial or troop contributions are being shared, with the latter driven by jointly produced country-specific benefits. Financial burden sharing can also differ between United Nations (UN)-led and non-UN-led peacekeeping operations, wherein country-specific benefits are especially important for the latter. Many articles gauge peacekeeping effectiveness by the mission’s ability to maintain the peace or to protect lives for a set time period. More recently, multiple criteria are raised for evaluating peacekeeping in today’s world of multifaceted peacebuilding operations. PMID:28989181
Tevatron lower temperature operation
International Nuclear Information System (INIS)
Theilacker, J.C.
1994-07-01
This year saw the completion of three accelerator improvement projects (AIP) and two capital equipment projects pertaining to the Tevatron cryogenic system. The projects result in the ability to operate the Tevatron at lower temperature, and thus higher energy. Each project improves a subsystem by expanding capabilities (refrigerator controls), ensuring reliability (valve box, subatmospheric hardware, and compressor D), or enhancing performance (cold compressors and coldbox II). In January of 1994, the Tevatron operated at an energy of 975 GeV for the first time. This was the culmination, of many years of R ampersand D, power testing in a sector (one sixth) of the Tevatron, and final system installation during the summer of 1993. Although this is a modest increase in energy, the discovery potential for the Top quark is considerably improved
NRC operation center's function
International Nuclear Information System (INIS)
Weiss, E.W.
1987-01-01
The Nuclear Regulatory Commission has maintained a 24-hour-a-day, 365 days-a-year, manned Operations Center since the emergency incident at the Three Mile Island Nuclear Power Plant in 1979. The Center functions as the NRC's point of direct communication through dedicated telephone lines for reports of significant events at licensed nuclear power plants and certain fuel cycle facilities. The Center has become a key element in the agency's emergency preparedness. The effectiveness of the NRC Operations Center depends in large measure on complete and accurate reports from the licensees. The information provided is used to: identify generic safety issues and precursor events that may compromise plant safety; develop licensee performance trends that are used to adjust NRC regulatory emphasis; and, evaluate and provide for the appropriate NRC response to events in a real time mode
1993-01-01
C Language Integrated Production System (CLIPS), a NASA-developed expert systems program, is used by American Airlines for three purposes: as a rapid prototyping tool; to develop production prototypes; and to develop production application. An example of the latter is CLIPS' use in "Hub S1AAshing," a knowledge based system that recommends contingency plans when severe schedule reductions must be made. Hub S1AAshing has replaced a manual, labor intensive process. It saves time and allows Operations Control Coordinators to handle more difficult situations. Because the system assimilates much of the information necessary to facilitate educated decision making, it minimizes negative impact in situations where it is impossible to operate all flights.
Train operation in emergencies
Jia, Limin; Qin, Yong
2017-01-01
This book presents the latest findings on train operation theories and methods in the context of emergencies. It examines and assesses a range of aspects—including the definition of a railway emergency, transport organization modes in emergencies, calculating railway transport capacity in emergencies, line planning in emergencies, train re-pathing in emergencies and train re-scheduling in emergencies—that are urgently needed in the railway transportation field, which faces the serious challenge of dealing with emergencies worldwide. The book highlights the latest research results in an integrated and systematic way, and the methodology presented is oriented on real-world problems, allowing it to be used not only directly in railway operational management, but also as the point of departure for further applications or theoretical research. As such, the book will be of considerable interest to graduate students and researchers in the field of traffic and transportation engineering.>.
Operational Shock Complexity Theory
2005-05-26
Theory : Recommendations For The National Strategy To Defeat Terrorism.” Student Issue Paper, Center for Strategic Leadership , US Army War College, July...Lens of Complexity Theory : Recommendations For The National Strategy To Defeat Terrorism.” (Student Issue Paper, Center for Strategic Leadership , US...planners managed to cause confusion in the enemy’s internal model by operating in an unexpected manner. 140 Glenn E. James, “Chaos Theory : The
Gaussian operations and privacy
International Nuclear Information System (INIS)
Navascues, Miguel; Acin, Antonio
2005-01-01
We consider the possibilities offered by Gaussian states and operations for two honest parties, Alice and Bob, to obtain privacy against a third eavesdropping party, Eve. We first extend the security analysis of the protocol proposed in [Navascues et al. Phys. Rev. Lett. 94, 010502 (2005)]. Then, we prove that a generalized version of this protocol does not allow one to distill a secret key out of bound entangled Gaussian states
2015 Special Operations Essays
2015-05-01
Glicken Turnley Ph.D., Cultural Anthropology Galisteo Consulting Group and JSOU Senior Fellow Francisco R. Wong-Diaz J.D., Ph.D., Political Science...missions a fragile state’s police must undertake. SF possess the cultural and linguistic training necessary to overcome personal and professional...and even participate in operations, while avoiding misunderstandings. Cultural and linguistic training are only two of the many resources indig
1990-02-12
Dyar , Vice Admiral,. IhX AmehbIiaaz Qj t Cong~3rL The Story 21 Admrml icmn fln .’:jl Tu~ ~rner. P. 923. 2. Joter A. Italy and Philip A. Crowi, Jb aig n...officers to attend the Naval War College in 1920 . Following the War College he was in the War Plans Division of Naval Operations and the Joint Army
ĎURKOV, Milan
2012-01-01
This bachelor?s thesis gives an overview of the operating system BSD Unix. The theoretical part of the work describes the history, the present and the basic information about the single distributions of this system. It also describes characteristics of the BSD kernel and natively used filesystem UFS which also compares with the Linux filesystem Ext4. The work also comprises description of the BSD license and its comparison with the GNU GPL license. The practical part of the thesis then descri...
Bayesian operational risk models
Silvia Figini; Lijun Gao; Paolo Giudici
2013-01-01
Operational risk is hard to quantify, for the presence of heavy tailed loss distributions. Extreme value distributions, used in this context, are very sensitive to the data, and this is a problem in the presence of rare loss data. Self risk assessment questionnaires, if properly modelled, may provide the missing piece of information that is necessary to adequately estimate op- erational risks. In this paper we propose to embody self risk assessment data into suitable prior distributions, and ...
Education Payload Operation - Demonstrations
Keil, Matthew
2009-01-01
Education Payload Operation - Demonstrations (EPO-Demos) are recorded video education demonstrations performed on the International Space Station (ISS) by crewmembers using hardware already onboard the ISS. EPO-Demos are videotaped, edited, and used to enhance existing NASA education resources and programs for educators and students in grades K-12. EPO-Demos are designed to support the NASA mission to inspire the next generation of explorers.
DEFF Research Database (Denmark)
Buhl, Kenneth Øhlenschlæger
2012-01-01
Formålet med denne artikel er at se nærmere på erfaringerne fra den maritime kampagne under den militære indsats i konflikten i Libyen i 2011, som i NATO regi blev kendt som Operation Unified Protector (OUP). Dækningen i de danske medier fokuserede primært på luftkampagnen, hvilket må tilskrives,...
Operational electricity transmission rates
International Nuclear Information System (INIS)
Roggen, M.
1997-01-01
In a liberalized electricity market both the consumers and the producers of electricity must pay for the use of the power transmission network. Thus, the net manager has unlimited options to realize efficiency improvements. A neutral and transparent management of the power grid is necessary to avoid disturbance of the market. KEMA Consulting translated abstract ideas and strategic advices to operational concepts in its report 'A framework for the determination of tariffs of the transport in the Dutch electricity sector'
2011-11-01
recognized the importance of strategic communication at the theater level in Veracruz in 1847. Realizing the influence of the Catholic Church on...Mexican society, Scott attended Mass with his staff at the Veracruz Cathedral to display the respect of U.S. forces. He further ordered U.S. soldiers to...operate freely in cyberspace. Data processing speeds and digital storage media continue to grow exponentially with competitive markets that drive sales
Pressurised water reactor operation
International Nuclear Information System (INIS)
Birnie, S.; Lamonby, J.K.
1987-01-01
The operation of a pressurized water reactor (PWR) is described with respect to the procedure for a unit start-up. The systems details and numerical data are for a four loop PWR station of the design proposed for Sizewell-'B', United Kingdom. A description is given of: the initial conditions, filling the reactor coolant system (RCS), heat-up and pressurisation of the RCS, secondary system preparations, reactor start-up, and reactivity control at power. (UK)
Averaging operations on matrices
Indian Academy of Sciences (India)
2014-07-03
Jul 3, 2014 ... Arithmetic mean of objects in a space need not lie in the space. [Frechet; 1948] Finding mean of right-angled triangles. S = {(x,y,z) ∈ R+3 : x2 + y2 = z2}. = {. [ z x − ιy x + ιy z. ] : x,y,z > 0,z2 = x2 + y2}. Surface of right triangles : Arithmetic mean not on S. Tanvi Jain. Averaging operations on matrices ...
International Nuclear Information System (INIS)
1993-01-01
It is reported that energy policy was designed following the European Bank for Reconstruction and Development review of the most pressing energy issues confronting Central and Eastern Europe and the republics of the former Soviet Union. The main features of the policy described in the document set the general framework for the Bank's energy operations. Energy strategies for particular countries are designed as an integral part of the Bank's individual country strategies. Tabs
Operator ordering and causality
Plimak, L. I.; Stenholm, S. T.
2011-01-01
It is shown that causality violations [M. de Haan, Physica 132A, 375, 397 (1985)], emerging when the conventional definition of the time-normal operator ordering [P.L.Kelley and W.H.Kleiner, Phys.Rev. 136, A316 (1964)] is taken outside the rotating wave approximation, disappear when the amended definition [L.P. and S.S., Annals of Physics, 323, 1989 (2008)] of this ordering is used.
Averaging operations on matrices
Indian Academy of Sciences (India)
2014-07-03
Jul 3, 2014 ... flow at each voxel of brain scan. • Elasticity: 6 × 6 pd matrices model stress tensors. • Machine Learning: n × n pd matrices occur as kernel matrices. ... then the expected extension of geometric mean A1/2B1/2 is not even self-adjoint, leave alone positive definite. Tanvi Jain. Averaging operations on matrices ...
CH Packaging Operations Manual
Energy Technology Data Exchange (ETDEWEB)
None, None
2009-05-27
This document provides the user with instructions for assembling a payload. All the steps in Subsections 1.2, Preparing 55-Gallon Drum Payload Assembly; 1.3, Preparing "Short" 85-Gallon Drum Payload Assembly (TRUPACT-II and HalfPACT); 1.4, Preparing "Tall" 85-Gallon Drum Payload Assembly (HalfPACT only); 1.5, Preparing 100-Gallon Drum Payload Assembly; 1.6, Preparing Shielded Container Payload Assembly; 1.7, Preparing SWB Payload Assembly; and 1.8, Preparing TDOP Payload Assembly, must be completed, but may be performed in any order as long as radiological control steps are not bypassed. Transport trailer operations, package loading and unloading from transport trailers, hoisting and rigging activities such as ACGLF operations, equipment checkout and shutdown, and component inspection activities must be performed, but may be performed in any order and in parallel with other activities as long as radiological control steps are not bypassed. Steps involving OCA/ICV lid removal/installation and payload removal/loading may be performed in parallel if there are multiple operators working on the same packaging. Steps involving removal/installation of OCV/ICV upper and lower main O-rings must be performed in sequence, except as noted.
International Nuclear Information System (INIS)
Veretenov, V.Yu.; Volkov, A.I.; Gurevich, M.I.; Kozik, V.S.; Pod'yachev, E.I.; Shapiro, M.L.
1974-01-01
A disc operational system is proposed, which is based on the file structure and designed for use in a BESM-6 computer with the software system comprising a dispatcher DD-73 and a monitor 'Dubna'. The main distinguishing feature of the disc operational system is the decentralization of the file system. Each disc package is an independent file unaffected by the state of the other disc packages. The use of several disc packages is allowed. The above feature of the disc operational system makes it possible to simplify the language of communication with the system, to give the user the opportunity of controlling the file quite independently, and to simplify the maintenance of the discs by the computer personnel. One and the same disc can be simultaneously addressed by all problems in the processor (both mathematical and service). A single file, however, may be used in the recording mode by only one problem. The description presented is the instruction for users. It also describes special possibilities open to the system programmers [ru
Operational health physics training
Energy Technology Data Exchange (ETDEWEB)
NONE
1992-06-01
The initial four sections treat basic information concerning atomic structure and other useful physical quantities, natural radioactivity, the properties of {alpha}, {beta}, {gamma}, x rays and neutrons, and the concepts and units of radiation dosimetry (including SI units). Section 5 deals with biological effects and the risks associated with radiation exposure. Background radiation and man-made sources are discussed next. The basic recommendations of the ICRP concerning dose limitations: justification, optimization (ALARA concepts and applications) and dose limits are covered in Section seven. Section eight is an expanded version of shielding, and the internal dosimetry discussion has been extensively revised to reflect the concepts contained in the MIRD methodology and ICRP 30. The remaining sections discuss the operational health physics approach to monitoring radiation. Individual sections include radiation detection principles, instrument operation and counting statistics, health physics instruments and personnel monitoring devices. The last five sections deal with the nature of, operation principles of, health physics aspects of, and monitoring approaches to air sampling, reactors, nuclear safety, gloveboxes and hot cells, accelerators and x ray sources. Decontamination, waste disposal and transportation of radionuclides are added topics. Several appendices containing constants, symbols, selected mathematical topics, and the Chart of the Nuclides, and an index have been included.
Operational health physics training
International Nuclear Information System (INIS)
1988-09-01
The initial four sections treat basic information concerning atomic structure and other useful physical quantities, natural radioactivity, the properties of α, β, γ, x rays and neutrons, and the concepts and units of radiation dosimetry (including SI units). Section 5 deals with biological effects and the risks associated with radiation exposure. Background radiation and man-made sources are discussed next. The basic recommendations of the ICRP concerning dose limitations: justification, optimization (ALARA concepts and applications) and dose limits are covered in Section seven. Section eight is an expanded version of shielding, and the internal dosimetry discussion has been extensively revised to reflect the concepts contained in the MIRD methodology and ICRP 30. The remaining sections discuss the operational health physics approach to monitoring radiation. Individual sections include radiation detection principles, instrument operation and counting statistics, health physics instruments and personnel monitoring devices. The last five sections deal with the nature of, operation principles of, health physics aspects of, and monitoring approaches to air sampling, reactors, nuclear safety, gloveboxes and hot cells, accelerators and x ray sources. Decontamination, waste disposal and transportation of radionuclides are added topics. Several appendices containing constants, symbols, selected mathematical topics, and the Chart of the Nuclides, and an index have been included