Twelfth workshop on geothermal reservoir engineering: Proceedings

Energy Technology Data Exchange (ETDEWEB)

Ramey, H.J. Jr.; Kruger, P.; Miller, F.G.; Horne, R.N.; Brigham, W.E.; Rivera, J. (Stanford Geothermal Program)

1987-01-22

Preface The Twelfth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 20-22, 1987. The year ending December 1986 was very difficult for the domestic geothermal industry. Low oil prices caused a sharp drop in geothermal steam prices. We expected to see some effect upon attendance at the Twelfth Workshop. To our surprise, the attendance was up by thirteen from previous years, with one hundred and fifty-seven registered participants. Eight foreign countries were represented: England, France, Iceland, Italy, Japan, Mexico, New Zealand, and Turkey. Despite a worldwide surplus of oil, international geothermal interest and development is growing at a remarkable pace. There were forty-one technical presentations at the Workshop. All of these are published as papers in this Proceedings volume. Seven technical papers not presented at the Workshop are also published; they concern geothermal developments and research in Iceland, Italy, and New Zealand. In addition to these forty-eight technical presentations or papers, the introductory address was given by Henry J. Ramey, Jr. from the Stanford Geothermal Program. The Workshop Banquet speaker was John R. Berg from the Department of Energy. We thank him for sharing with the Workshop participants his thoughts on the expectations of this agency in the role of alternative energy resources, specifically geothermal, within the country???s energy framework. His talk is represented as a paper in the back of this volume. The chairmen of the technical sessions made an important contribution to the workshop. Other than Stanford faculty members they included: M. Gulati, K. Goyal, G.S. Bodvarsson, A.S. Batchelor, H. Dykstra, M.J. Reed, A. Truesdell, J.S. Gudmundsson, and J.R. Counsil. The Workshop was organized by the Stanford Geothermal Program faculty, staff, and students. We would like to thank Jean Cook, Marilyn King, Amy Osugi, Terri Ramey, and Rosalee Benelli for their valued help with the meeting

Riemannian geometry of thermodynamics and systems with repulsive power-law interactions.

Science.gov (United States)

Ruppeiner, George

2005-07-01

A Riemannian geometric theory of thermodynamics based on the postulate that the curvature scalar R is proportional to the inverse free energy density is used to investigate three-dimensional fluid systems of identical classical point particles interacting with each other via a power-law potential energy gamma r(-alpha) . Such systems are useful in modeling melting transitions. The limit alpha-->infinity corresponds to the hard sphere gas. A thermodynamic limit exists only for short-range (alpha>3) and repulsive (gamma>0) interactions. The geometric theory solutions for given alpha>3 , gamma>0 , and any constant temperature T have the following properties: (1) the thermodynamics follows from a single function b (rho T(-3/alpha) ) , where rho is the density; (2) all solutions are equivalent up to a single scaling constant for rho T(-3/alpha) , related to gamma via the virial theorem; (3) at low density, solutions correspond to the ideal gas; (4) at high density there are solutions with pressure and energy depending on density as expected from solid state physics, though not with a Dulong-Petit heat capacity limit; (5) for 33.7913 a phase transition is required to go between these regimes; (7) for any alpha>3 we may include a first-order phase transition, which is expected from computer simulations; and (8) if alpha-->infinity, the density approaches a finite value as the pressure increases to infinity, with the pressure diverging logarithmically in the density difference.

Discrete repulsive oscillator wavefunctions

International Nuclear Information System (INIS)

Munoz, Carlos A; Rueda-Paz, Juvenal; Wolf, Kurt Bernardo

2009-01-01

For the study of infinite discrete systems on phase space, the three-dimensional Lorentz algebra and group, so(2,1) and SO(2,1), provide a discrete model of the repulsive oscillator. Its eigenfunctions are found in the principal irreducible representation series, where the compact generator-that we identify with the position operator-has the infinite discrete spectrum of the integers Z, while the spectrum of energies is a double continuum. The right- and left-moving wavefunctions are given by hypergeometric functions that form a Dirac basis for l 2 (Z). Under contraction, the discrete system limits to the well-known quantum repulsive oscillator. Numerical computations of finite approximations raise further questions on the use of Dirac bases for infinite discrete systems.

Is repulsion good for the health of chimeras?

Science.gov (United States)

Jalan, Sarika; Ghosh, Saptarshi; Patra, Bibhabasu

2017-10-01

Yes! Very much so. A chimera state refers to the coexistence of a coherent-incoherent dynamical evolution of identically coupled oscillators. We investigate the impact of multiplexing of a layer having repulsively coupled oscillators on the occurrence of chimeras in the layer having attractively coupled identical oscillators. We report that there exists an enhancement in the appearance of the chimera state in one layer of the multiplex network in the presence of repulsive coupling in the other layer. Furthermore, we show that a small amount of inhibition or repulsive coupling in one layer is sufficient to yield the chimera state in another layer by destroying its synchronized behavior. These results can be used to obtain insight into dynamical behaviors of those systems where both attractive and repulsive couplings exist among their constituents.

Twelfth cranial nerve involvement in Guillian Barre syndrome.

Science.gov (United States)

Nanda, Subrat Kumar; Jayalakshmi, Sita; Ruikar, Devashish; Surath, Mohandas

2013-07-01

Guillian Barre Syndrome (GBS) is associated with cranial nerve involvement. Commonest cranial nerves involved were the facial and bulbar (IXth and Xth). Involvement of twelfth cranial nerve is rare in GBS. We present a case of GBS in a thirteen years old boy who developed severe tongue weakness and wasting at two weeks after the onset of GBS. The wasting and weakness of tongue improved at three months of follow up. Brief review of the literature about XIIth cranial nerve involvement in GBS is discussed.

Twelfth cranial nerve involvement in Guillian Barre syndrome

OpenAIRE

Subrat Kumar Nanda; Sita Jayalakshmi; Devashish Ruikar; Mohandas Surath

2013-01-01

Guillian Barre Syndrome (GBS) is associated with cranial nerve involvement. Commonest cranial nerves involved were the facial and bulbar (IXth and Xth). Involvement of twelfth cranial nerve is rare in GBS. We present a case of GBS in a thirteen years old boy who developed severe tongue weakness and wasting at two weeks after the onset of GBS. The wasting and weakness of tongue improved at three months of follow up. Brief review of the literature about XIIth cranial nerve involvement in GBS is...

Distinct collective states due to trade-off between attractive and repulsive couplings

Science.gov (United States)

Sathiyadevi, K.; Chandrasekar, V. K.; Senthilkumar, D. V.; Lakshmanan, M.

2018-03-01

We investigate the effect of repulsive coupling together with an attractive coupling in a network of nonlocally coupled oscillators. To understand the complex interaction between these two couplings we introduce a control parameter in the repulsive coupling which plays a crucial role in inducing distinct complex collective patterns. In particular, we show the emergence of various cluster chimera death states through a dynamically distinct transition route, namely the oscillatory cluster state and coherent oscillation death state as a function of the repulsive coupling in the presence of the attractive coupling. In the oscillatory cluster state, the oscillators in the network are grouped into two distinct dynamical states of homogeneous and inhomogeneous oscillatory states. Further, the network of coupled oscillators follow the same transition route in the entire coupling range. Depending upon distinct coupling ranges, the system displays different number of clusters in the death state and oscillatory state. We also observe that the number of coherent domains in the oscillatory cluster state exponentially decreases with increase in coupling range and obeys a power-law decay. Additionally, we show analytical stability for observed solitary state, synchronized state, and incoherent oscillation death state.

The Discovery of Gravitational Repulsion by Johannes Droste

Science.gov (United States)

McGruder, Charles Hosewell; VanDerMeer, B. Wieb

2018-01-01

In 1687 Newton published his universal law of gravitation, which states that the gravitational force is always attractive. This law is based on our terrestrial experience with slowly moving bodies (v Einstein completed his theory of general relativity (also referred to as Einstein’s Theory of Gravitation), which is valid not just for slowly moving bodies but also for those with relativistic velocities. In 1916 Johannes Droste submitted a PhD thesis on general relativity to his advisor, H.A. Lorentz. In it he calculated the motion of a particle in what he called a “single center” and today we call the Schwarzschild field and found that highly relativistic particles experience gravitational repulsion. Thus, his thesis written in Dutch and never before translated contains the discovery of gravitational repulsion. Because of its historical importance we translate the entire section of his thesis containing the discovery of gravitational repulsion. We also translate his thesis in the hope of clearing up a major historical misconception. Namely, that David Hilbert in 1917 discovered gravitational repulsion. In fact, Hilbert rediscovered it, apparently completely independent of Droste’s work. Finally we note that one of the biggest mysteries of astrophysics is the question of how highly energetic particles in relativistic jets and cosmic rays are accelerated. It has been suggested that gravitational repulsion is the mechanism responsible for these phenomena. An historical understanding of gravitational repulsion is therefore pertinent.

Searching for the Exit in a Maze? Or Setting Sail for New Horizons? Metaphors by Twelfth Grade Students for Learning Mathematics

Science.gov (United States)

Guner, Necdet

2013-01-01

This study examines and classifies the metaphors that twelfth grade students formulated to describe the concept of "learning mathematics". The sample of the study consists of 669 twelfth grade students (317 female, 352 male) of two Anatolian and two vocational high schools located in the city center of Denizli. The following questions…

Twelfth cranial nerve involvement in Guillian Barre syndrome

Directory of Open Access Journals (Sweden)

Subrat Kumar Nanda

2013-01-01

Full Text Available Guillian Barre Syndrome (GBS is associated with cranial nerve involvement. Commonest cranial nerves involved were the facial and bulbar (IXth and Xth. Involvement of twelfth cranial nerve is rare in GBS. We present a case of GBS in a thirteen years old boy who developed severe tongue weakness and wasting at two weeks after the onset of GBS. The wasting and weakness of tongue improved at three months of follow up. Brief review of the literature about XIIth cranial nerve involvement in GBS is discussed.

Twelfth annual US DOE low-level waste management conference

International Nuclear Information System (INIS)

1990-01-01

The papers in this document comprise the proceedings of the Department of Energy's Twelfth Annual Low-Level Radioactive Waste Management Conference, which was held in Chicago, Illinois, on August 28 and 29, 1990. General subjects addressed during the conference included: mixed waste, low-level radioactive waste tracking and transportation, public involvement, performance assessment, waste stabilization, financial assurance, waste minimization, licensing and environmental documentation, below-regulatory-concern waste, low-level radioactive waste temporary storage, current challenges, and challenges beyond 1990

Repulsion of polarized particles from two-dimensional materials

Science.gov (United States)

Rodríguez-Fortuño, Francisco J.; Picardi, Michela F.; Zayats, Anatoly V.

2018-05-01

Repulsion of nanoparticles, molecules, and atoms from surfaces can have important applications in nanomechanical devices, microfluidics, optical manipulation, and atom optics. Here, through the solution of a classical scattering problem, we show that a dipole source oscillating at a frequency ω can experience a robust and strong repulsive force when its near-field interacts with a two-dimensional material. As an example, the case of graphene is considered, showing that a broad bandwidth of repulsion can be obtained at frequencies for which propagation of plasmon modes is allowed 0 chemical potential tunable electrically or by chemical doping.

Role of Coulomb repulsion in multilayer cuprate superconductor

International Nuclear Information System (INIS)

Singh Chauhan, Ekta; Singh, Vipul; Masih, Piyush

2012-01-01

Although BCS theory completely neglects coulomb repulsion; Anderson and Morel showed very early that it plays a central role in superconductivity. Since all high T c superconductors are based on the structure of closely spaced square planner CuO 2 layers and role of interlayer interaction plays important role in enhancement of T c . Therefore the work has been dealt with 'Role of Coulomb repulsion in Multilayer Cuprate Superconductors'. An expression for transition temperature T c is obtained by using simple integration technique and is numerically solved. It has found that T c decreases with electronic repulsion. (author)

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.

Twelfth annual US DOE low-level waste management conference

Energy Technology Data Exchange (ETDEWEB)

1990-01-01

The papers in this document comprise the proceedings of the Department of Energy's Twelfth Annual Low-Level Radioactive Waste Management Conference, which was held in Chicago, Illinois, on August 28 and 29, 1990. General subjects addressed during the conference included: mixed waste, low-level radioactive waste tracking and transportation, public involvement, performance assessment, waste stabilization, financial assurance, waste minimization, licensing and environmental documentation, below-regulatory-concern waste, low-level radioactive waste temporary storage, current challenges, and challenges beyond 1990.

Ultracold fermions with repulsive interactions

Directory of Open Access Journals (Sweden)

Ketterle W.

2013-08-01

Full Text Available An ultracold Fermi gas with repulsive interaction has been studied. For weak interactions, the atomic gas is metastable, and the interactions were characterized by obtaining the isothermal compressibility from atomic density profiles. For stronger interactions (kFa ≈ 1, rapid conversion into Feshbach molecules is observed. When the conversion rate becomes comparable to the Fermi energy divided by η, the atomic gas cannot reach equilibrium without forming pairs. This precludes the predicted transition to a ferromagnetic state (Stoner transition. The absence of spin fluctuations proves that the gas stays paramagnetic. In free space, a Fermi gas with strong short-range repulsion does not exist because of the rapid coupling to molecular states.

Attractive and repulsive magnetic suspension systems overview

Science.gov (United States)

Cope, David B.; Fontana, Richard R.

1992-01-01

Magnetic suspension systems can be used in a wide variety of applications. The decision of whether to use an attractive or repulsive suspension system for a particular application is a fundamental one which must be made during the design process. As an aid to the designer, we compare and contrast attractive and repulsive magnetic suspension systems and indicate whether and under what conditions one or the other system is preferred.

Instant transformation of learned repulsion into motivational "wanting".

Science.gov (United States)

Robinson, Mike J F; Berridge, Kent C

2013-02-18

Learned cues for pleasant reward often elicit desire, which, in addicts, may become compulsive. According to the dominant view in addiction neuroscience and reinforcement modeling, such desires are the simple products of learning, coming from a past association with reward outcome. We demonstrate that cravings are more than merely the products of accumulated pleasure memories-even a repulsive learned cue for unpleasantness can become suddenly desired via the activation of mesocorticolimbic circuitry. Rats learned repulsion toward a Pavlovian cue (a briefly-inserted metal lever) that always predicted an unpleasant Dead Sea saltiness sensation. Yet, upon first reencounter in a novel sodium-depletion state to promote mesocorticolimbic reactivity (reflected by elevated Fos activation in ventral tegmentum, nucleus accumbens, ventral pallidum, and the orbitofrontal prefrontal cortex), the learned cue was instantly transformed into an attractive and powerful motivational magnet. Rats jumped and gnawed on the suddenly attractive Pavlovian lever cue, despite never having tasted intense saltiness as anything other than disgusting. Instant desire transformation of a learned cue contradicts views that Pavlovian desires are essentially based on previously learned values (e.g., prediction error or temporal difference models). Instead desire is recomputed at reencounter by integrating Pavlovian information with the current brain/physiological state. This powerful brain transformation reverses strong learned revulsion into avid attraction. When applied to addiction, related mesocorticolimbic transformations (e.g., drugs or neural sensitization) of cues for already-pleasant drug experiences could create even more intense cravings. This cue/state transformation helps define what it means to say that addiction hijacks brain limbic circuits of natural reward. Copyright © 2013 Elsevier Ltd. All rights reserved.

Casimir Repulsion between Metallic Objects in Vacuum

International Nuclear Information System (INIS)

Levin, Michael; McCauley, Alexander P.; Rodriguez, Alejandro W.; Reid, M. T. Homer; Johnson, Steven G.

2010-01-01

We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic metals. The system does not support stable levitation, as the particle is unstable to displacements away from the symmetry axis.

Proceedings of the twelfth Symposium of Atomic Energy Research

International Nuclear Information System (INIS)

Vidovszky, Istvan

2002-11-01

The present volume contains 45 papers, presented on the twelfth Symposium of Atomic Energy Research, held in Sunny Beach, Bulgaria, 22-28 September 2002. The papers are presented in their original form, i. e. no corrections or modifications were carried out. The content of this volume is divided into thematic groups: Core Monitoring, Surveillance and Testing, Safety Issues, Core Operation and Fuel Management, Spectral and Core Calculation Methods, Spent Fuel Transmutations and Decommissioning, Neutron Kinetics and reactor Dynamics Methods, Poster Session - according to the presentation sequence on the Symposium

Coulomb repulsion in short polypeptides.

Science.gov (United States)

Norouzy, Amir; Assaf, Khaleel I; Zhang, Shuai; Jacob, Maik H; Nau, Werner M

2015-01-08

Coulomb repulsion between like-charged side chains is presently viewed as a major force that impacts the biological activity of intrinsically disordered polypeptides (IDPs) by determining their spatial dimensions. We investigated short synthetic models of IDPs, purely composed of ionizable amino acid residues and therefore expected to display an extreme structural and dynamic response to pH variation. Two synergistic, custom-made, time-resolved fluorescence methods were applied in tandem to study the structure and dynamics of the acidic and basic hexapeptides Asp6, Glu6, Arg6, Lys6, and His6 between pH 1 and 12. (i) End-to-end distances were obtained from the short-distance Förster resonance energy transfer (sdFRET) from N-terminal 5-fluoro-l-tryptophan (FTrp) to C-terminal Dbo. (ii) End-to-end collision rates were obtained for the same peptides from the collision-induced fluorescence quenching (CIFQ) of Dbo by FTrp. Unexpectedly, the very high increase of charge density at elevated pH had no dynamical or conformational consequence in the anionic chains, neither in the absence nor in the presence of salt, in conflict with the common view and in partial conflict with accompanying molecular dynamics simulations. In contrast, the cationic peptides responded to ionization but with surprising patterns that mirrored the rich individual characteristics of each side chain type. The contrasting results had to be interpreted, by considering salt screening experiments, N-terminal acetylation, and simulations, in terms of an interplay of local dielectric constant and peptide-length dependent side chain charge-charge repulsion, side chain functional group solvation, N-terminal and side chain charge-charge repulsion, and side chain-side chain as well as side chain-backbone interactions. The common picture that emerged is that Coulomb repulsion between water-solvated side chains is efficiently quenched in short peptides as long as side chains are not in direct contact with each

Measured long-range repulsive Casimir-Lifshitz forces.

Science.gov (United States)

Munday, J N; Capasso, Federico; Parsegian, V Adrian

2009-01-08

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces. However, as recognized in the theories of Casimir, Polder and Lifshitz, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies. Here we show experimentally that, in accord with theoretical prediction, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir-Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction.

Charged singularities: repulsive effects

Energy Technology Data Exchange (ETDEWEB)

De Felice, F; Nobili, L [Padua Univ. (Italy). Ist. di Fisica; Calvani, M [Padua Univ. (Italy). Ist. di Astronomia

1980-07-01

The repulsive phenomena which a particle experiences in the vicinity of a naked singularity are investigated in the Kerr-Newman space-time. The aim is to extend the knowledge of this fact to charged solutions and to have a direct indication of how, in these situations, the gravitational and electrostatic interactions are competing.

Positive effects of repulsion on boundedness in a fully parabolic attraction-repulsion chemotaxis system with logistic source

Science.gov (United States)

Wang, Wei; Zhuang, Mengdi; Zheng, Sining

2018-02-01

In this paper we study the global boundedness of solutions to the fully parabolic attraction-repulsion chemotaxis system with logistic source: ut = Δu - χ∇ ṡ (u∇v) + ξ∇ ṡ (u∇w) + f (u), vt = Δv - βv + αu, wt = Δw - δw + γu, subject to homogeneous Neumann boundary conditions in a bounded and smooth domain Ω ⊂Rn (n ≥ 1), where χ, α, ξ, γ, β and δ are positive constants, and f : R → R is a smooth function generalizing the logistic source f (s) = a - bsθ for all s ≥ 0 with a ≥ 0, b > 0 and θ ≥ 1. It is shown that when the repulsion cancels the attraction (i.e. χα = ξγ), the solution is globally bounded if n ≤ 3, or θ >θn : = min ⁡ {n+2}/4, n/√{n2 + 6 n + 17 }/-n2 - 3 n + 4 4 } with n ≥ 2. Therefore, due to the inhibition of repulsion to the attraction, in any spatial dimension, the exponent θ is allowed to take values less than 2 such that the solution is uniformly bounded in time.

Quest for Casimir repulsion between Chern-Simons surfaces

Science.gov (United States)

Fialkovsky, Ignat; Khusnutdinov, Nail; Vassilevich, Dmitri

2018-04-01

In this paper we critically reconsider the Casimir repulsion between surfaces that carry the Chern-Simons interaction (corresponding to the Hall-type conductivity). We present a derivation of the Lifshitz formula valid for arbitrary planar geometries and discuss its properties. This analysis allows us to resolve some contradictions in the previous literature. We compute the Casimir energy for two surfaces that have constant longitudinal and Hall conductivities. The repulsion is possible only if both surfaces have Hall conductivities of the same sign. However, there is a critical value of the longitudinal conductivity above which the repulsion disappears. We also consider a model where both parity odd and parity even terms in the conductivity are produced by the polarization tensor of surface modes. In contrast to the previous publications [L. Chen and S.-L. Wan, Phys. Rev. B 84, 075149 (2011), 10.1103/PhysRevB.84.075149; Phys. Rev. B 85, 115102 (2012), 10.1103/PhysRevB.85.115102], we include the parity anomaly term. This term ensures that the conductivities vanish for infinitely massive surface modes. We find that at least for a single mode, regardless of the sign and value of its mass, there is no Casimir repulsion.

Special issue “International Geomagnetic Reference Field—the twelfth generation”

OpenAIRE

Thébault, E.; Finlay, C. C.; Toh, H.

2015-01-01

This special issue of Earth, Planets and Space, synthesizes the efforts made during the construction of the twelfth generation of the International Geomagnetic Reference Field (IGRF-12) that was released online in December 2014 (http://www.ngdc.noaa.gov/IAGA/vmod/ igrf.html). The IGRF-12 is a series of standard mathematical models describing the large scale internal part of the Earth’s magnetic field between epochs 1900.0 and 2015.0 with a forecast to epoch 2020.0. This activity has been main...

Measured long-range repulsive Casimir–Lifshitz forces

Science.gov (United States)

Munday, J. N.; Capasso, Federico; Parsegian, V. Adrian

2014-01-01

Quantum fluctuations create intermolecular forces that pervade macroscopic bodies1–3. At molecular separations of a few nanometres or less, these interactions are the familiar van der Waals forces4. However, as recognized in the theories of Casimir, Polder and Lifshitz5–7, at larger distances and between macroscopic condensed media they reveal retardation effects associated with the finite speed of light. Although these long-range forces exist within all matter, only attractive interactions have so far been measured between material bodies8–11. Here we show experimentally that, in accord with theoretical prediction12, the sign of the force can be changed from attractive to repulsive by suitable choice of interacting materials immersed in a fluid. The measured repulsive interaction is found to be weaker than the attractive. However, in both cases the magnitude of the force increases with decreasing surface separation. Repulsive Casimir–Lifshitz forces could allow quantum levitation of objects in a fluid and lead to a new class of switchable nanoscale devices with ultra-low static friction13–15. PMID:19129843

Phaco-efficiency test and re-aspiration analysis of repulsed particle in phacoemulsification.

Science.gov (United States)

Kim, Jae-hyung; Ko, Dong-Ah; Kim, Jae Yong; Kim, Myoung Joon; Tchah, Hungwon

2013-04-01

To measure the efficiency of phacoemulsification, we have developed a new experimental model for testing phaco-efficiency and analyzed re-aspiration of repulsed particles. Using a Kitaro wetlab system, a piece of blood agar (BA) was placed in an artificial chamber and the phacoemulsifier was placed horizontally. The settings of the phacoemulsifier (Infiniti, Alcon Laboratories) were 26 cc/min for aspiration, 350 cc/min for vacuum, and 95 cm of bottle height. The time to remove BAs was measured using Ozil 100 %, Ozil 40 %, and longitudinal 40 % of phaco power. The angle between the re-aspirated BA particles and the axis of the phacoemulsifier (re-aspiration zone, degree) was analyzed. The average time (seconds) to remove BAs was lower in the Ozil 100 % and the Ozil 40 % mode than in the longitudinal mode (0.37 ± 0.39, 0.85 ± 0.57, and 2.22 ± 1.40 respectively, P value < 0.01). Repulsion exceeding 1 mm occurred more frequently in the longitudinal mode than in the Ozil 100 % mode (100 % vs 40 %, P value = 0.01, Fisher's exact test). The average of re-aspiration zone was 25.9 ± 14.5 in the longitudinal 40 % and 54.0 ± 23.0 in the Ozil 40 % (P value = 0.016). The Ozil mode was more efficient than the longitudinal mode. In addition, the Ozil mode provided less repulsion and wider aspiration zone.

Superconductivity in a Repulsive Model

DEFF Research Database (Denmark)

Feldman, Joel; Knoerrer, Horst; Sinclair, Robert

1997-01-01

A two-dimensional system of Fermions with classical dispersion relationand a purely repulsive delta function pair potential generates the dominant attractive coupling in the third order Bethe-Salpeter approximation for the Cooper channel. This suggests that the ground state is an l=1 superconductor....

Le mythe comme détour dans Twelfth Night The Myth as a Diversion in Twelfth Night

Directory of Open Access Journals (Sweden)

Cécile Mauré

2009-06-01

Full Text Available Being only rarely mentioned in the text, the myth might seem an anecdotal and trivial detail. The study of the myth of Echo and Narcissus in Twelfth Night shows us however that it is a decisive element in the reading and the understanding of the play. The references are numerous and often implicit. The characters themselves alternately play the roles of Echo and Narcissus. The play is structured as if it were a mirror in which the characters endlessly duplicate each other and echo their own words. Shakespeare plays with the different versions of the myth that he often blends with subtlety. For the sake of comedy, he dares to parody and demythologize Ovid’s story. The myth seems to divert our attention from the direction of the text but closer analysis suggests the reverse and invites us to find the meaning of the play which can be seen as a real labyrinth.

Twelfth annual conference of the CFD Society of Canada (CFD 2004). Proceedings

International Nuclear Information System (INIS)

Khalid, M.; Chen, S.; McIlwain, S.

2004-01-01

The Twelfth Annual Conference of the CFD Society of Canada, CFD 2004, was held in Ottawa, Ontario from May 9-11, 2004. The proceedings consists of 24 sessions covering the following topics: fluid structure interactions; multiphase and multi-species flows; mesh methods; turbulence; DNS/LES; supersonic and hypersonic flows; heat transfer; combustion and detonation; flow physics; aerodynamics; applications; algorithms; environmental flows; magnetohydrodynamics and electrohydrodynamics; biofluids; and, combustion and smoke management

Electron attraction mediated by Coulomb repulsion.

Science.gov (United States)

Hamo, A; Benyamini, A; Shapir, I; Khivrich, I; Waissman, J; Kaasbjerg, K; Oreg, Y; von Oppen, F; Ilani, S

2016-07-21

One of the defining properties of electrons is their mutual Coulomb repulsion. However, in solids this basic property may change; for example, in superconductors, the coupling of electrons to lattice vibrations makes the electrons attract one another, leading to the formation of bound pairs. Fifty years ago it was proposed that electrons can be made attractive even when all of the degrees of freedom in the solid are electronic, by exploiting their repulsion from other electrons. This attraction mechanism, termed 'excitonic', promised to achieve stronger and more exotic superconductivity. Yet, despite an extensive search, experimental evidence for excitonic attraction has yet to be found. Here we demonstrate this attraction by constructing, from the bottom up, the fundamental building block of the excitonic mechanism. Our experiments are based on quantum devices made from pristine carbon nanotubes, combined with cryogenic precision manipulation. Using this platform, we demonstrate that two electrons can be made to attract each other using an independent electronic system as the 'glue' that mediates attraction. Owing to its tunability, our system offers insights into the underlying physics, such as the dependence of the emergent attraction on the underlying repulsion, and the origin of the pairing energy. We also demonstrate transport signatures of excitonic pairing. This experimental demonstration of excitonic pairing paves the way for the design of exotic states of matter.

Designing learning apparatus to promote twelfth grade students’ understanding of digital technology concept: A preliminary studies

Science.gov (United States)

Marlius; Kaniawati, I.; Feranie, S.

2018-05-01

A preliminary learning design using relay to promote twelfth grade student’s understanding of logic gates concept is implemented to see how well it’s to adopted by six high school students, three male students and three female students of twelfth grade. This learning design is considered for next learning of digital technology concept i.e. data digital transmition and analog. This work is a preliminary study to design the learning for large class. So far just a few researches designing learning design related to digital technology with relay. It may due to this concept inserted in Indonesian twelfth grade curriculum recently. This analysis is focus on student difficulties trough video analysis to learn the concept. Based on our analysis, the recommended thing for redesigning learning is: students understand first about symbols and electrical circuits; the Student Worksheet is made in more detail on the assembly steps to the project board; mark with symbols at points in certain places in the circuit for easy assembly; assembly using relays by students is enough until is the NOT’s logic gates and the others that have been assembled so that effective time. The design of learning using relays can make the relay a liaison between the abstract on the digital with the real thing of it, especially in the circuit of symbols and real circuits. Besides it is expected to also enrich the ability of teachers in classroom learning about digital technology.

Repulsive DNA-DNA interactions accelerate viral DNA packaging in phage phi29

OpenAIRE

Keller, Nicholas; delToro, Damian; Grimes, Shelley; Jardine, Paul J.; Smith, Douglas E.

2014-01-01

We use optical tweezers to study the effect of attractive versus repulsive DNA-DNA interactions on motor-driven viral packaging. Screening of repulsive interactions accelerates packaging, but induction of attractive interactions by spermidine3+ causes heterogeneous dynamics. Acceleration is observed in a fraction of complexes, but most exhibit slowing and stalling, suggesting that attractive interactions promote nonequilibrium DNA conformations that impede the motor. Thus, repulsive interacti...

Repulsion-based model for contact angle saturation in electrowetting.

Science.gov (United States)

Ali, Hassan Abdelmoumen Abdellah; Mohamed, Hany Ahmed; Abdelgawad, Mohamed

2015-01-01

We introduce a new model for contact angle saturation phenomenon in electrowetting on dielectric systems. This new model attributes contact angle saturation to repulsion between trapped charges on the cap and base surfaces of the droplet in the vicinity of the three-phase contact line, which prevents these surfaces from converging during contact angle reduction. This repulsion-based saturation is similar to repulsion between charges accumulated on the surfaces of conducting droplets which causes the well known Coulombic fission and Taylor cone formation phenomena. In our model, both the droplet and dielectric coating were treated as lossy dielectric media (i.e., having finite electrical conductivities and permittivities) contrary to the more common assumption of a perfectly conducting droplet and perfectly insulating dielectric. We used theoretical analysis and numerical simulations to find actual charge distribution on droplet surface, calculate repulsion energy, and minimize energy of the total system as a function of droplet contact angle. Resulting saturation curves were in good agreement with previously reported experimental results. We used this proposed model to predict effect of changing liquid properties, such as electrical conductivity, and system parameters, such as thickness of the dielectric layer, on the saturation angle, which also matched experimental results.

Modulation of repulsive forces between neurofilaments by sidearm phosphorylation

International Nuclear Information System (INIS)

Kumar, Sanjay; Hoh, Jan H.

2004-01-01

Recent studies have advanced the notion that the axonal organization of neurofilaments (NFs) is based on mutual steric repulsion between the unstructured 'sidearm' domains of adjacent NFs. Here, we present experimental evidence that these repulsive forces are modulated by the degree of sidearm phosphorylation. When NFs are sedimented into a gelatinous pellet, pellet volume falls with increasing ionic strength and enzymatic dephosphorylation; sedimentation of phosphorylated NFs in the presence of divalent cations also dramatically reduces pellet volume. Further, atomic force microscopy imaging of isolated mammalian NFs reveals robust exclusion of colloidal particles from the NF backbone that is reduced at high ionic strength and attenuated when the filaments are enzymatically dephosphorylated. Phosphate-phosphate repulsion on the NF sidearm appears to modulate NF excluded volume in a graded fashion, thereby controlling axonal NF organization through interfilament forces

The Impact of Past Language Arts Teachers on the Reading Motivation of Twelfth Grade Students

Science.gov (United States)

Shepard, Courtney A.

2017-01-01

Adolescents' motivation to read continues to decline. The purpose of this embedded single case study was to explore adolescent reading motivation to determine some ways in which adolescents are motivated to read. Through purposeful sampling, the participants included seven twelfth grade students and three English Language Arts teachers in grades…

The International Geomagnetic Reference Field: the twelfth generation

Science.gov (United States)

Thebault, Erwan; Finlay, Christopher; The IGRF Working Group

2015-04-01

The IGRF is an internationally-agreed reference model of the Earth's magnetic field produced under the auspices of the International Association of Geomagnetism and Aeronomy. The IGRF-12 is the latest update of this well-known model which is used each year by many thousands of users for both industrial and scientific purposes. In October 2014, ten institutions worldwide have made contributions to the IGRF. These models were evaluated and the twelfth generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2014. In this presentation, we will report on the IGRF activities, briefly describe the candidate models, summarize the evaluation of models performed by different independent teams, show how the IGRF-12 models were calculated and finally discuss some of the main magnetic features of this new model.

Repulsive DNA-DNA interactions accelerate viral DNA packaging in phage Phi29.

Science.gov (United States)

Keller, Nicholas; delToro, Damian; Grimes, Shelley; Jardine, Paul J; Smith, Douglas E

2014-06-20

We use optical tweezers to study the effect of attractive versus repulsive DNA-DNA interactions on motor-driven viral packaging. Screening of repulsive interactions accelerates packaging, but induction of attractive interactions by spermidine(3+) causes heterogeneous dynamics. Acceleration is observed in a fraction of complexes, but most exhibit slowing and stalling, suggesting that attractive interactions promote nonequilibrium DNA conformations that impede the motor. Thus, repulsive interactions facilitate packaging despite increasing the energy of the theoretical optimum spooled DNA conformation.

Bodies That Don't Matter: Possibilities of Female Homoeroticism in Twelfth Night

OpenAIRE

松尾, 江津子

2007-01-01

This article attempts to consider (non-)representation of female same-sex love in William Shakespeare's Twelfth Night in the cultural and political context of early modern England. The first question here is whether female homoeroticism existed in early modern English society. Valerie Traub shows how female same-sex desire and sexual activity did exist in spite of the lack of their historical documents in early modern England. According to her, female homoerotic desire was regarded as“ insign...

Design of a smart haptic system for repulsive force control under irregular manipulation environment

International Nuclear Information System (INIS)

Lee, Sang-Rock; Choi, Seung-Hyun; Choi, Seung-Bok; Cho, Myeong-Woo

2014-01-01

This paper describes how to make an operator feel the desired repulsive force in a haptic system. When an operator manipulates a haptic system, the repulsive force of the operator varies significantly, depending on many factors such as position, velocity and force. In order to reflect the desired repulsive force to the operator, it is commonly known that a haptic system must compensate for irregularly changing forces. The irregularity of the forces, however, has discouraged many researchers from establishing a clear principle on how to make the operator feel the desired repulsive force. To resolve this problem, we introduce a smart haptic framework that can reflect the desired repulsive force to the operator, regardless of the operator’s movement. A dummy governing equation technique is introduced and used to calculate the proper actuating force in real time. The actuating force is generated by a PID controller. To verify the proposed method, a mathematical proof is offered to show that the repulsive force converges to the desired repulsive force. Additionally, to demonstrate the performance of the proposed method, simulational and experimental tests are implemented. (paper)

Repulsive Casimir-Polder potential by a negative reflecting surface

Science.gov (United States)

Yuan, Qi-Zhang

2015-07-01

We present a scheme to generate an all-range long repulsive Casimir-Polder potential between a perfect negative reflecting surface and a ground-state atom. The repulsive potential is stable and does not decay with time. The Casimir-Polder potential is proportional to z-2 at short atom-surface distances and to z-4 at long atom-surface distances. Because of these advantages, this potential can help in building quantum reflectors, quantum levitating devices, and waveguides for matter waves.

Discontinuous nature of the repulsive-to-attractive colloidal glass transition.

Science.gov (United States)

van de Laar, T; Higler, R; Schroën, K; Sprakel, J

2016-03-04

In purely repulsive colloidal systems a glass transition can be reached by increasing the particle volume fraction beyond a certain threshold. The resulting glassy state is governed by configurational cages which confine particles and restrict their motion. A colloidal glass may also be formed by inducing attractive interactions between the particles. When attraction is turned on in a repulsive colloidal glass a re-entrant solidification ensues. Initially, the repulsive glass melts as free volume in the system increases. As the attraction strength is increased further, this weakened configurational glass gives way to an attractive glass in which motion is hindered by the formation of physical bonds between neighboring particles. In this paper, we study the transition from repulsive-to-attractive glasses using three-dimensional imaging at the single-particle level. We show how the onset of cage weakening and bond formation is signalled by subtle changes in local structure. We then demonstrate the discontinuous nature of the solid-solid transition, which is marked by a critical onset at a threshold bonding energy. Finally, we highlight how the interplay between bonding and caging leads to complex and heterogeneous dynamics at the microscale.

Bosons system with finite repulsive interaction: self-consistent field method

International Nuclear Information System (INIS)

Renatino, M.M.B.

1983-01-01

Some static properties of a boson system (T = zero degree Kelvin), under the action of a repulsive potential are studied. For the repulsive potential, a model was adopted consisting of a region where it is constant (r c ), and a decay as 1/r (r > r c ). The self-consistent field approximation used takes into account short range correlations through a local field corrections, which leads to an effective field. The static structure factor S(q-vector) and the effective potential ψ(q-vector) are obtained through a self-consistent calculation. The pair-correlation function g(r-vector) and the energy of the collective excitations E(q-vector) are also obtained, from the structure factor. The density of the system and the parameters of the repulsive potential, that is, its height and the size of the constant region were used as variables for the problem. The results obtained for S(q-vector), g(r-vector) and E(q-vector) for a fixed ratio r o /r c and a variable λ, indicates the raising of a system structure, which is more noticeable when the potential became more repulsive. (author)

The similarity of attractive and repulsive forces on a lattice

Science.gov (United States)

Mirahmadi, Marjan-S.; Fatollahi, Amir H.; Khorrami, Mohammad

2015-07-01

On a lattice, as the momentum space is compact, the kinetic energy is bounded not only from below but also from above. It is shown that this somehow removes the distinction between repulsive and attractive forces. In particular, it is seen that a region with attractive force would appear forbidden for states with energies higher than a certain value, while repulsive forces could develop bound-states. An explicit transformation is introduced which transforms the spectrum of a system corresponding to a repulsive force, to that of a similar system corresponding to an attractive force. Explicit numerical examples are presented for discrete energies of bound-states of a particle experiencing repulsive force by a piecewise constant potential. Finally, the parameters of a specific one-dimensional (1D) translationally invariant system on continuum are tuned so that the energy of the system resembles the kinetic energy of a system on a 1D lattice. In particular, the parameters are tuned so that while the width of the first energy band and its position are kept finite, the gap between the first energy band and the next energy band goes to infinity, so that effectively only the first energy band is relevant.

Cigarette Smoking Trajectories From Sixth to Twelfth Grade: Associated Substance Use and High School Dropout.

Science.gov (United States)

Orpinas, Pamela; Lacy, Beth; Nahapetyan, Lusine; Dube, Shanta R; Song, Xiao

2016-02-01

The purpose of this longitudinal study was to identify distinct trajectories of cigarette smoking from sixth to twelfth grade and to characterize these trajectories by use of other drugs and high school dropout. The diverse sample for this analysis consisted of a cohort of 611 students from Northeast Georgia who participated in the Healthy Teens Longitudinal Study (2003-2009). Students completed seven yearly assessments from sixth through twelfth grade. We used semi-parametric, group-based modeling to identify groups of students whose smoking behavior followed a similar progression over time. Current smoking (past 30 day) increased from 6.9% among sixth graders to 28.8% among twelfth graders. Four developmental trajectories of cigarette smoking were identified: Abstainers/Sporadic Users (71.5% of the sample), Late Starters (11.3%), Experimenters (9.0%), and Continuous Users (8.2%). The Abstainer/Sporadic User trajectory was composed of two distinct groups: those who never reported any tobacco use (True Abstainers) and those who reported sporadic, low-level use (Sporadic Users). The True Abstainers reported significantly less use of alcohol and other drugs and lower dropout rates than students in all other trajectories, and Sporadic Users had worse outcomes than True Abstainers. Experimenters and Continuous Users reported the highest drug use. Over one-third of Late Starters (35.8%) and almost half of Continuous Users (44.4%) dropped out of high school. Cigarette smoking was associated with behavioral and academic problems. Results support early and continuous interventions to reduce use of tobacco and other drugs and prevent high school dropout. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A soundtrack between allurement and repulsion

DEFF Research Database (Denmark)

Have, Iben

2011-01-01

By mixing industrial, metallic sounds and organic, throaty sounds, Kitchen Sink creates an acoustic universe which is at once repulsive and alluring. The article takes a phenomenological and deep listening approach to investigate how the soundtrack of Kitchen Sink contributes to the ambiguous...... narrative of the film....

Crossover from phonon-mediated to repulsion-induced superconducting pairing with large momentum

International Nuclear Information System (INIS)

Belyavsky, V.I.; Kopaev, Yu.V.; Nguyen, N.T.; Togushova, Yu.N.

2005-01-01

There are asymmetric and symmetric solutions of the self-consistency equation which takes into account both phonon-mediated and Coulomb pairing interactions. The first of them leads to the order parameter with a nodal line and, in the case of pairing with large momentum, exists at any repulsive and attractive strengths. The second one arises if the attraction exceeds a level depending on the repulsion strength and dominates the pairing in the strong attraction limit. The competition of attraction and repulsion results in unusual isotope-effect exponent observed in the cuprates

Geometric constructions for repulsive gravity and quantization

International Nuclear Information System (INIS)

Hohmann, Manuel

2010-11-01

In this thesis we present two geometric theories designed to extend general relativity. It can be seen as one of the aims of such theories to model the observed accelerating expansion of the universe as a gravitational phenomenon, or to provide a mathematical structure for the formulation of quantum field theories on curved spacetimes and quantum gravity. This thesis splits into two parts: In the first part we consider multimetric gravity theories containing N>1 standard model copies which interact only gravitationally and repel each other in the Newtonian limit. The dynamics of each of the standard model copies is governed by its own metric tensor. We show that the antisymmetric case, in which the mutual repulsion between the different matter sectors is of equal strength compared to the attractive gravitational force within each sector, is prohibited by a no-go theorem for N=2. We further show that this theorem does not hold for N>2 by explicitly constructing an antisymmetric multimetric repulsive gravity theory. We then examine several properties of this theory. Most notably, we derive a simple cosmological model and show that the accelerating expansion of the late universe can indeed be explained by the mutual repulsion between the different matter sectors. We further present a simple model for structure formation and show that our model leads to the formation of filament-like structures and voids. Finally, we show that multimetric repulsive gravity is compatible with high-precision solar system data using the parametrized post-Newtonian formalism. In the second part of the thesis we propose a mathematical model of quantum spacetime as an infinite-dimensional manifold locally homeomorphic to an appropriate Schwartz space. This extends and unifies both the standard function space construction of quantum mechanics and the differentiable manifold structure of classical spacetime. In this picture we demonstrate that classical spacetime emerges as a finite

Geometric constructions for repulsive gravity and quantization

Energy Technology Data Exchange (ETDEWEB)

Hohmann, Manuel

2010-11-15

In this thesis we present two geometric theories designed to extend general relativity. It can be seen as one of the aims of such theories to model the observed accelerating expansion of the universe as a gravitational phenomenon, or to provide a mathematical structure for the formulation of quantum field theories on curved spacetimes and quantum gravity. This thesis splits into two parts: In the first part we consider multimetric gravity theories containing N>1 standard model copies which interact only gravitationally and repel each other in the Newtonian limit. The dynamics of each of the standard model copies is governed by its own metric tensor. We show that the antisymmetric case, in which the mutual repulsion between the different matter sectors is of equal strength compared to the attractive gravitational force within each sector, is prohibited by a no-go theorem for N=2. We further show that this theorem does not hold for N>2 by explicitly constructing an antisymmetric multimetric repulsive gravity theory. We then examine several properties of this theory. Most notably, we derive a simple cosmological model and show that the accelerating expansion of the late universe can indeed be explained by the mutual repulsion between the different matter sectors. We further present a simple model for structure formation and show that our model leads to the formation of filament-like structures and voids. Finally, we show that multimetric repulsive gravity is compatible with high-precision solar system data using the parametrized post-Newtonian formalism. In the second part of the thesis we propose a mathematical model of quantum spacetime as an infinite-dimensional manifold locally homeomorphic to an appropriate Schwartz space. This extends and unifies both the standard function space construction of quantum mechanics and the differentiable manifold structure of classical spacetime. In this picture we demonstrate that classical spacetime emerges as a finite

Repulsive gravitational forces: A possible mechanism for clustering

International Nuclear Information System (INIS)

Eisenstaedt, J.

1977-01-01

It is well known that, in a homogeneous cosmological universe, a positive cosmological constant induces repulsive forces. We show here that in a locally inhomogeneous cosmological model these repulsive forces are related to the sign of q, the deceleration parameter of the associated cosmological space, and to the sign of m, the apparent mass of the central perturbation (which can be negative with a positive energy density everywhere). When q is almost zero--crossing the value zero--small random perturbations of the matter density are the sources of a gravitational instability which can generate a mechanism of fragmentation in an a priori homogeneous universe

An Adaptation-Induced Repulsion Illusion in Tactile Spatial Perception

Directory of Open Access Journals (Sweden)

Lux Li

2017-06-01

Full Text Available Following focal sensory adaptation, the perceived separation between visual stimuli that straddle the adapted region is often exaggerated. For instance, in the tilt aftereffect illusion, adaptation to tilted lines causes subsequently viewed lines with nearby orientations to be perceptually repelled from the adapted orientation. Repulsion illusions in the nonvisual senses have been less studied. Here, we investigated whether adaptation induces a repulsion illusion in tactile spatial perception. In a two-interval forced-choice task, participants compared the perceived separation between two point-stimuli applied on the forearms successively. Separation distance was constant on one arm (the reference and varied on the other arm (the comparison. In Experiment 1, we took three consecutive baseline measurements, verifying that in the absence of manipulation, participants’ distance perception was unbiased across arms and stable across experimental blocks. In Experiment 2, we vibrated a region of skin on the reference arm, verifying that this focally reduced tactile sensitivity, as indicated by elevated monofilament detection thresholds. In Experiment 3, we applied vibration between the two reference points in our distance perception protocol and discovered that this caused an illusory increase in the separation between the points. We conclude that focal adaptation induces a repulsion aftereffect illusion in tactile spatial perception. The illusion provides clues as to how the tactile system represents spatial information. The analogous repulsion aftereffects caused by adaptation in different stimulus domains and sensory systems may point to fundamentally similar strategies for dynamic sensory coding.

Optical absorptions of an exciton in a quantum ring: Effect of the repulsive core

International Nuclear Information System (INIS)

Xie, Wenfang

2013-01-01

We study the optical absorptions of an exciton in a quantum ring. The quantum ring is described as a circular quantum dot with a repulsive core. The advantage of our methodology is that one can investigate the influence of the repulsive core by varying two parameters in the confinement potential. The linear, third-order nonlinear and total optical absorption coefficients have been examined with the change of the confinement potential. The results show that the optical absorptions are strongly affected by the repulsive core. Moreover, the repulsive core can influence the oscillation in the resonant peak of the absorption coefficients.

Small traveling clusters in attractive and repulsive Hamiltonian mean-field models.

Science.gov (United States)

Barré, Julien; Yamaguchi, Yoshiyuki Y

2009-03-01

Long-lasting small traveling clusters are studied in the Hamiltonian mean-field model by comparing between attractive and repulsive interactions. Nonlinear Landau damping theory predicts that a Gaussian momentum distribution on a spatially homogeneous background permits the existence of traveling clusters in the repulsive case, as in plasma systems, but not in the attractive case. Nevertheless, extending the analysis to a two-parameter family of momentum distributions of Fermi-Dirac type, we theoretically predict the existence of traveling clusters in the attractive case; these findings are confirmed by direct N -body numerical simulations. The parameter region with the traveling clusters is much reduced in the attractive case with respect to the repulsive case.

Mapping between Hamiltonians with attractive and repulsive potentials on a lattice

International Nuclear Information System (INIS)

Joglekar, Yogesh N.

2010-01-01

Through a simple and exact analytical derivation, we show that for a particle on a lattice there is a one-to-one correspondence between the spectrum in the presence of an attractive potential V and its repulsive counterpart -V. For a Hermitian potential, this result implies that the number of localized states is the same in both attractive and repulsive cases although these states occur above (below) the band continuum for the repulsive (attractive) case. For a PT-symmetric potential that is odd under parity, our result implies that, in the PT-unbroken phase, the energy eigenvalues are symmetric around zero and that the corresponding eigenfunctions are closely related to each other.

Spontaneous symmetry breaking in vortex systems with two repulsive lengthscales.

Science.gov (United States)

Curran, P J; Desoky, W M; Milosević, M V; Chaves, A; Laloë, J-B; Moodera, J S; Bending, S J

2015-10-23

Scanning Hall probe microscopy (SHPM) has been used to study vortex structures in thin epitaxial films of the superconductor MgB2. Unusual vortex patterns observed in MgB2 single crystals have previously been attributed to a competition between short-range repulsive and long-range attractive vortex-vortex interactions in this two band superconductor; the type 1.5 superconductivity scenario. Our films have much higher levels of disorder than bulk single crystals and therefore both superconducting condensates are expected to be pushed deep into the type 2 regime with purely repulsive vortex interactions. We observe broken symmetry vortex patterns at low fields in all samples after field-cooling from above Tc. These are consistent with those seen in systems with competing repulsions on disparate length scales, and remarkably similar structures are reproduced in dirty two band Ginzburg-Landau calculations, where the simulation parameters have been defined by experimental observations. This suggests that in our dirty MgB2 films, the symmetry of the vortex structures is broken by the presence of vortex repulsions with two different lengthscales, originating from the two distinct superconducting condensates. This represents an entirely new mechanism for spontaneous symmetry breaking in systems of superconducting vortices, with important implications for pinning phenomena and high current density applications.

Trapping a Knot into Tight Conformations by Intra-Chain Repulsions

Directory of Open Access Journals (Sweden)

Liang Dai

2017-02-01

Full Text Available Knots can occur in biopolymers such as DNA and peptides. In our previous study, we systematically investigated the effects of intra-chain interactions on knots and found that long-range repulsions can surprisingly tighten knots. Here, we use this knowledge to trap a knot into tight conformations in Langevin dynamics simulations. By trapping, we mean that the free energy landscape with respect to the knot size exhibits a potential well around a small knot size in the presence of long-range repulsions, and this potential can well lead to long-lived tight knots when its depth is comparable to or larger than thermal energy. We tune the strength of intra-chain repulsion such that a knot is weakly trapped. Driven by thermal fluctuations, the knot can escape from the trap and is then re-trapped. We find that the knot switches between tight and loose conformations—referred to as “knot breathing”. We use a Yukawa potential to model screened electrostatic interactions to explore the relevance of knot trapping and breathing in charged biopolymers. We determine the minimal screened length and the minimal strength of repulsion for knot trapping. We find that Coulomb-induced knot trapping is possible to occur in single-stranded DNA and peptides for normal ionic strengths.

Twelfth symposium on biotechnology for fuels and chemicals: Program and abstracts

International Nuclear Information System (INIS)

Scheitlin, F.M.

1990-01-01

This report is the program and abstracts of the twelfth symposium on biotechnology for fuels and chemicals, held on May 7--11, 1990, at Gatlinburg, Tennessee. The symposium, sponsored by the Department of Energy, Oak Ridge National Laboratory, Solar Energy Research Institute, Badger Engineers, Inc., Gas Research Institute, and American Chemical Society, consists of five sessions: Session 1, thermal, chemical, and biological processing; Session 2 and 3, applied biological research; Session 4, bioengineering research; and Session 5, biotechnology, bioengineering, and the solution of environmental problems. It also consists of a poster session of the same five subject categories

Twelfth symposium on biotechnology for fuels and chemicals: Program and abstracts

Energy Technology Data Exchange (ETDEWEB)

Scheitlin, F.M. (ed.)

1990-01-01

This report is the program and abstracts of the twelfth symposium on biotechnology for fuels and chemicals, held on May 7--11, 1990, at Gatlinburg, Tennessee. The symposium, sponsored by the Department of Energy, Oak Ridge National Laboratory, Solar Energy Research Institute, Badger Engineers, Inc., Gas Research Institute, and American Chemical Society, consists of five sessions: Session 1, thermal, chemical, and biological processing; Session 2 and 3, applied biological research; Session 4, bioengineering research; and Session 5, biotechnology, bioengineering, and the solution of environmental problems. It also consists of a poster session of the same five subject categories.

Twelfth Semiannual Report of the Commission to the Congress. Major Activities in the Atomic Energy Programs, January - June 1952

Energy Technology Data Exchange (ETDEWEB)

Dean, Gordon

1952-07-01

The document represents the twelfth semiannual Atomic Energy Commission (AEC) report to Congress. The report sums up the major activities and developments in the national atomic energy program covering the period January - June 1952.

Pattern formation in annular systems of repulsive particles

International Nuclear Information System (INIS)

Marschler, Christian; Starke, Jens; Sørensen, Mads P.; Gaididei, Yuri B.; Christiansen, Peter L.

2016-01-01

General particle models with symmetric and asymmetric repulsion are studied and investigated for finite-range and exponential interaction in an annulus. In the symmetric case transitions from one- to multi-lane behavior including multistability are observed for varying particle density and for a varying curvature with fixed density. Hence, the system cannot be approximated by a periodic channel. In the asymmetric case, which is important in pedestrian dynamics, we reveal an inhomogeneous new phase, a traveling wave reminiscent of peristaltic motion. - Highlights: • An asymmetrically interacting repulsive particle model is introduced. • Multi-stability is found in a pedestrian dynamics model. • Transitions from one- to multi-lane behavior are studied numerically.

75 FR 11116 - Certain Pasta from Italy: Notice of Amended Final Results of the Twelfth Antidumping Duty...

Science.gov (United States)

2010-03-10

... DEPARTMENT OF COMMERCE International Trade Administration [A-475-818] Certain Pasta from Italy... certain pasta from Italy for the period of review (POR) of July 1, 2007, through June 30, 2008. See Certain Pasta from Italy: Notice of Final Results of the Twelfth Administrative Review, 75 FR 6352...

Cucker-Smale Flocking with Bounded Cohesive and Repulsive Forces

Directory of Open Access Journals (Sweden)

Qiang Song

2013-01-01

Full Text Available This paper proposes two Cucker-Smale-type flocking models by introducing both cohesive and repulsive forces to second-order multiagent systems. Under some mild conditions on the initial state of the flocking system, it is shown that the velocity consensus of the agents can be reached independent of the parameter which describes the decay of communication rates. In particular, the collision between any two agents can always be avoided by designing an appropriate bounded repulsive function based on the initial energy of the flock. Numerical examples are given to demonstrate the effectiveness of the theoretical analysis.

Idiopathic Ninth, Tenth, and Twelfth Cranial Nerve Palsy with Ipsilateral Headache: A Case Report

Directory of Open Access Journals (Sweden)

Sun Seung-Ho

2012-12-01

Full Text Available Objective: This case report is to report the effect of Korean traditional treatment for idiopathic ninth, tenth, and twelfth cranial nerve palsy with ipsilateral headache. Methods: The medical history and imaging and laboratory test of a 39-year-old man with cranial palsy were tested to identify the cause of disease. A 0.2-mL dosage of Hwangyeonhaedoktang pharmacopuncture was administered at CV23 and CV17, respectively. Acupuncture was applied at P06, Li05, TE05, and G37 on the right side of the body. Zhuapiandutongbang (左偏頭痛方 was administered at 30 minutes to 1 hour after mealtime three times a day. The symptoms were investigated using Visual Analogue Scale (VAS. Results: The results of magnetic resonance imaging (MRI, computed tomography (CT, and laboratory tests were normal. The medical history showed no trauma, other illnesses, family history of diseases, medications, smoking, drinking and so on. All symptoms disappeared at the 10th day of treatment. Conclusion: Korean traditional treatment such as acupuncture, pharmcopuncture, and herbal medicine for the treatment of ninth, tenth, and twelfth cranial nerve palsy of unknown origin is suggested to be effective even though this conclusion is based on a single.

Effect of hydration repulsion on nanoparticle agglomeration evaluated via a constant number Monte–Carlo simulation

International Nuclear Information System (INIS)

Liu, Haoyang Haven; Lanphere, Jacob; Walker, Sharon; Cohen, Yoram

2015-01-01

The effect of hydration repulsion on the agglomeration of nanoparticles in aqueous suspensions was investigated via the description of agglomeration by the Smoluchowski coagulation equation using constant number Monte–Carlo simulation making use of the classical DLVO theory extended to include the hydration repulsion energy. Evaluation of experimental DLS measurements for TiO 2 , CeO 2 , SiO 2 , and α-Fe 2 O 3 (hematite) at high IS (up to 900 mM) or low |ζ-potential| (≥1.35 mV) demonstrated that hydration repulsion energy can be above electrostatic repulsion energy such that the increased overall repulsion energy can significantly lower the agglomerate diameter relative to the classical DLVO prediction. While the classical DLVO theory, which is reasonably applicable for agglomeration of NPs of high |ζ-potential| (∼>35 mV) in suspensions of low IS (∼<1 mM), it can overpredict agglomerate sizes by up to a factor of 5 at high IS or low |ζ-potential|. Given the potential important role of hydration repulsion over a range of relevant conditions, there is merit in quantifying this repulsion energy over a wide range of conditions as part of overall characterization of NP suspensions. Such information would be of relevance to improved understanding of NP agglomeration in aqueous suspensions and its correlation with NP physicochemical and solution properties. (paper)

Losses of off-site power at U.S. nuclear power plants -- through 1995. Final report

International Nuclear Information System (INIS)

Wyckoff, H.

1996-04-01

This report provides a database and summary analysis of losses of off-site power at US nuclear generating units. It includes the 16 years 1980 through 1995. This is the twelfth update of this database and analysis. During 1994 there were no losses of all off-site power and in 1995 only two short losses. Both the short term and long term US loss of all off-site power experience is extremely favorable. The frequency of losing all off-site power is an important input to many nuclear plant safety assessments. The industry's loss of all off-site power experience that is set forth in this report can provide perspective to plant specific probabilistic safety assessments

Solar Power Plants: Dark Horse in the Energy Stable

Science.gov (United States)

Caputo, Richard S.

1977-01-01

Twelfth in a series of reports on solar energy, this article provides information relating to the following questions: (1) economic cost of solar-thermal-electric central power plants; (2) cost comparison with nuclear or coal plants; (3) locations of this energy source; and (4) its use and social costs. (CS)

On the hydrodynamics of a solvent-saturated lipid bilayer. 1. Model of repulsion

International Nuclear Information System (INIS)

Bish, P.M.; Wendel, H.

1983-01-01

A semiphenomenological theory of steric repulsion in black lipid films is developed. The model employs the statistical mechanical formulation of the van der Waals theory of simple liquid-vapour interfaces; it is based on the picture that upon diminishing the film thickness the adjacent interfacial layers start overlapping in the film center raising the degree of orientation of the hydrocarbon segments present there. This fact causes a mutual repulsion of the two film surfaces. The general order parameter profile is found to depend on two parameters which are fixed by means of the results of an experiment which recorded the repulsive force as a function of film thickness. (Author) [pt

The role of local repulsion in superconductivity in the Hubbard–Holstein model

Energy Technology Data Exchange (ETDEWEB)

Lin, Chungwei, E-mail: clin@merl.com; Wang, Bingnan; Teo, Koon Hoo

2017-01-15

Highlights: • There exists an optimal Boson energy for superconductivity in Hubbard–Holstein model. • The electron-Boson coupling is essential for superconductivity, but the same coupling can lead to polaron insulator, which is against superconductivity. • The local Coulomb repulsion can sometimes enhance superconductivity. - Abstract: We examine the superconducting solution in the Hubbard–Holstein model using Dynamical Mean Field Theory. The Holstein term introduces the site-independent Boson fields coupling to local electron density, and has two competing influences on superconductivity: The Boson field mediates the effective electron-electron attraction, which is essential for the S-wave electron pairing; the same coupling to the Boson fields also induces the polaron effect, which makes the system less metallic and thus suppresses superconductivity. The Hubbard term introduces an energy penalty U when two electrons occupy the same site, which is expected to suppress superconductivity. By solving the Hubbard–Holstein model using Dynamical Mean Field theory, we find that the Hubbard U can be beneficial to superconductivity under some circumstances. In particular, we demonstrate that when the Boson energy Ω is small, a weak local repulsion actually stabilizes the S-wave superconducting state. This behavior can be understood as an interplay between superconductivity, the polaron effect, and the on-site repulsion: As the polaron effect is strong and suppresses superconductivity in the small Ω regime, the weak on-site repulsion reduces the polaron effect and effectively enhances superconductivity. Our calculation elucidates the role of local repulsion in the conventional S-wave superconductors.

Slow relaxation mode in concentrated oil-in-water microemulsions consisting of repulsive droplets

Science.gov (United States)

Hattori, Y.; Ushiki, H.; Courbin, L.; Panizza, P.

2007-02-01

The present contribution reports on the observation of two diffusive relaxation modes in a concentrated microemulsion made of repulsive droplets. These two modes can be interpreted in the frame of Weissman’s and Pusey’s theoretical pioneering works. The fast mode is associated to the collective diffusion of droplets whereas the slow one corresponds to the relaxation of droplet concentration fluctuations associated with composition and/or size. We show that (i) repulsive interactions considerably slow down the latter and (ii) a generalized Stokes Einstein relationship between its coefficient of diffusion and the Newtonian viscosity of the solutions, similar to the Walden’s rule for electrolytes, holds for concentrated microemulsion systems made of repulsive droplets.

One-loop quantum gravity repulsion in the early Universe.

Science.gov (United States)

Broda, Bogusław

2011-03-11

Perturbative quantum gravity formalism is applied to compute the lowest order corrections to the classical spatially flat cosmological Friedmann-Lemaître-Robertson-Walker solution (for the radiation). The presented approach is analogous to the approach applied to compute quantum corrections to the Coulomb potential in electrodynamics, or rather to the approach applied to compute quantum corrections to the Schwarzschild solution in gravity. In the framework of the standard perturbative quantum gravity, it is shown that the corrections to the classical deceleration, coming from the one-loop graviton vacuum polarization (self-energy), have (UV cutoff free) opposite to the classical repulsive properties which are not negligible in the very early Universe. The repulsive "quantum forces" resemble those known from loop quantum cosmology.

Overscreening-underscreening transition in the two-channel Kondo model induced by electron-electron repulsion

International Nuclear Information System (INIS)

Zhang Yumei; Chen Hong.

1995-09-01

The effects of the repulsion between the electrons on the two-channel Kondo problem are studied by use of the bosonization technique. Following Emery and Kivelson, we define a special case in the spin density wave sector, in which the impurity spin is actually detached from the dynamics of the electrons. The model is thus mapped to a local Sine-Gordon system. For weak repulsion, the basic features of the overscreening picture are maintained. However, at sufficient strong repulsion the system is driven into the weak coupling regime, hence an overscreening-underscreening transition emerges. (author). 22 refs

Melting-curve extrema from a repulsive ''step'' potential

International Nuclear Information System (INIS)

Young, D.A.; Alder, B.J.

1977-01-01

Molecular dynamics calculations in two dimensions for particles interacting with a repulsive ''step'' potential show melting-curve maxima and minima as well as solid-solid phase transitions. These features are similar to those observed in the phase diagram of cesium and cerium

The role of local repulsion in superconductivity in the Hubbard-Holstein model

Science.gov (United States)

Lin, Chungwei; Wang, Bingnan; Teo, Koon Hoo

2017-01-01

We examine the superconducting solution in the Hubbard-Holstein model using Dynamical Mean Field Theory. The Holstein term introduces the site-independent Boson fields coupling to local electron density, and has two competing influences on superconductivity: The Boson field mediates the effective electron-electron attraction, which is essential for the S-wave electron pairing; the same coupling to the Boson fields also induces the polaron effect, which makes the system less metallic and thus suppresses superconductivity. The Hubbard term introduces an energy penalty U when two electrons occupy the same site, which is expected to suppress superconductivity. By solving the Hubbard-Holstein model using Dynamical Mean Field theory, we find that the Hubbard U can be beneficial to superconductivity under some circumstances. In particular, we demonstrate that when the Boson energy Ω is small, a weak local repulsion actually stabilizesthe S-wave superconducting state. This behavior can be understood as an interplay between superconductivity, the polaron effect, and the on-site repulsion: As the polaron effect is strong and suppresses superconductivity in the small Ω regime, the weak on-site repulsion reduces the polaron effect and effectively enhances superconductivity. Our calculation elucidates the role of local repulsion in the conventional S-wave superconductors.

Highly effective photonic cue for repulsive axonal guidance.

Directory of Open Access Journals (Sweden)

Bryan J Black

Full Text Available In vivo nerve repair requires not only the ability to regenerate damaged axons, but most importantly, the ability to guide developing or regenerating axons along paths that will result in functional connections. Furthermore, basic studies in neuroscience and neuro-electronic interface design require the ability to construct in vitro neural circuitry. Both these applications require the development of a noninvasive, highly effective tool for axonal growth-cone guidance. To date, a myriad of technologies have been introduced based on chemical, electrical, mechanical, and hybrid approaches (such as electro-chemical, optofluidic flow and photo-chemical methods. These methods are either lacking in desired spatial and temporal selectivity or require the introduction of invasive external factors. Within the last fifteen years however, several attractive guidance cues have been developed using purely light based cues to achieve axonal guidance. Here, we report a novel, purely optical repulsive guidance technique that uses low power, near infrared light, and demonstrates the guidance of primary goldfish retinal ganglion cell axons through turns of up to 120 degrees and over distances of ∼90 µm.

Coulomb repulsion in (TMTSF)2X and (TMTTF)2X

DEFF Research Database (Denmark)

Mortensen, Kell; Engler, E. M.

1985-01-01

On the basis of studies of transport properties of (TMTSF)2 X, (TMTTF)2X and their binary alloys the authors discuss the role of on-site Coulomb repulsion relative to the transfer integrals. In TMTTF-salts U/ta are believed to be large, resulting in a Hubbard gap, whereas U/ta in TMTSF-salts are ......On the basis of studies of transport properties of (TMTSF)2 X, (TMTTF)2X and their binary alloys the authors discuss the role of on-site Coulomb repulsion relative to the transfer integrals. In TMTTF-salts U/ta are believed to be large, resulting in a Hubbard gap, whereas U/ta in TMTSF...

Phase diagram of Rydberg atoms with repulsive van der Waals interaction

International Nuclear Information System (INIS)

Osychenko, O. N.; Astrakharchik, G. E.; Boronat, J.; Lutsyshyn, Y.; Lozovik, Yu. E.

2011-01-01

We report a quantum Monte Carlo calculation of the phase diagram of bosons interacting with a repulsive inverse sixth power pair potential, a model for assemblies of Rydberg atoms in the local van der Waals blockade regime. The model can be parametrized in terms of just two parameters, the reduced density and temperature. Solidification happens to the fcc phase. At zero temperature, the transition density is found with the diffusion Monte Carlo method at density ρ=3.9 ((ℎ/2π) 2 /mC 6 ) 3/4 , where C 6 is the strength of the interaction. The solidification curve at nonzero temperature is studied with the path-integral Monte Carlo approach and is compared with transitions in corresponding harmonic and classical crystals. Relaxation mechanisms are considered in relation to present experiments.

Levodopa increases oxidative stress and repulsive guidance molecule A levels: a pilot study in patients with Parkinson's disease.

Science.gov (United States)

Müller, Thomas; Trommer, Isabel; Muhlack, Siegfried; Mueller, Bernhard K

2016-04-01

Exposure to free radicals influences synthesis, degradation and function of proteins, such as repulsive guidance molecule A. Decay of this protein is essential for neuronal maintenance and recovery. Levodopa elevates oxidative stress. Therefore levodopa may impact repulsive guidance molecule A metabolism. Objectives were to investigate plasma concentrations of repulsive guidance molecule A, levodopa, cysteine and cysteinyl-glycine before and 1 h after levodopa application in patients with Parkinson's disease. Cysteine and cysteinyl-glycine as biomarkers for oxidative stress exposure decreased, repulsive guidance molecule A and levodopa rose. Repulsive guidance molecule A remained unchanged in levodopa naïve patients, but particularly went up in patients on a prior chronic levodopa regimen. Decay of cysteine specifically cysteinyl-glycine results from an elevated glutathione generation with rising cysteine consumption respectively from the alternative glutathione transformation to its oxidized form glutathione disulfide after free radical scavenging. Repulsive guidance molecule A rise may inhibit physiologic mechanisms for neuronal survival.

Mode repulsion of ultrasonic guided waves in rails

CSIR Research Space (South Africa)

Loveday, Philip W

2018-03-01

Full Text Available . The modes can therefore be numbered in the same way that Lamb waves in plates are numbered, making it easier to communicate results. The derivative of the eigenvectors with respect to wavenumber contains the same repulsion term and shows how the mode shapes...

Spontaneous symmetry breaking due to the trade-off between attractive and repulsive couplings.

Science.gov (United States)

Sathiyadevi, K; Karthiga, S; Chandrasekar, V K; Senthilkumar, D V; Lakshmanan, M

2017-04-01

Spontaneous symmetry breaking is an important phenomenon observed in various fields including physics and biology. In this connection, we here show that the trade-off between attractive and repulsive couplings can induce spontaneous symmetry breaking in a homogeneous system of coupled oscillators. With a simple model of a system of two coupled Stuart-Landau oscillators, we demonstrate how the tendency of attractive coupling in inducing in-phase synchronized (IPS) oscillations and the tendency of repulsive coupling in inducing out-of-phase synchronized oscillations compete with each other and give rise to symmetry breaking oscillatory states and interesting multistabilities. Further, we provide explicit expressions for synchronized and antisynchronized oscillatory states as well as the so called oscillation death (OD) state and study their stability. If the Hopf bifurcation parameter (λ) is greater than the natural frequency (ω) of the system, the attractive coupling favors the emergence of an antisymmetric OD state via a Hopf bifurcation whereas the repulsive coupling favors the emergence of a similar state through a saddle-node bifurcation. We show that an increase in the repulsive coupling not only destabilizes the IPS state but also facilitates the reentrance of the IPS state.

Entropic Repulsion Between Fluctuating Surfaces

Science.gov (United States)

Janke, W.

The statistical mechanics of fluctuating surfaces plays an important role in a variety of physical systems, ranging from biological membranes to world sheets of strings in theories of fundamental interactions. In many applications it is a good approximation to assume that the surfaces possess no tension. Their statistical properties are then governed by curvature energies only, which allow for gigantic out-of-plane undulations. These fluctuations are the “entropic” origin of long-range repulsive forces in layered surface systems. Theoretical estimates of these forces for simple model surfaces are surveyed and compared with recent Monte Carlo simulations.

Electronic and Structural Properties of ABO3: Role of the B-O Coulomb Repulsions for Ferroelectricity.

Science.gov (United States)

Miura, Kaoru; Azuma, Masaki; Funakubo, Hiroshi

2011-01-17

We have investigated the role of the Ti-O Coulomb repulsions in the appearance of the ferroelectric state in BaTiO3 as well as the role of the Zn-O Coulomb repulsions in BiZn0.5Ti0.5O3, using a first-principles calculation with optimized structures. In tetragonal BaTiO3, it is found that the Coulomb repulsions between Ti 3s and 3p states and O 2s and 2p states have an important role for the appearance of Ti ion displacement. In BiZn0.5Ti0.5O3, on the other hand, the stronger Zn-O Coulomb repulsions, which are due to the 3s, 3p, and 3d (d10) states of the Zn ion, have more important role than the Ti-O Coulomb repulsions for the appearance of the tetragonal structure. Our suggestion is consistent with the other ferroelectric perovskite oxides ABO3 in the appearance of tetragonal structures as well as rhombohedral structures.

Maximum repulsed magnetization of a bulk superconductor with low pulsed field

International Nuclear Information System (INIS)

Tsuchimoto, M.; Kamijo, H.; Fujimoto, H.

2005-01-01

Pulsed field magnetization of a bulk high-T c superconductor (HTS) is important technique especially for practical applications of a bulk superconducting magnet. Full magnetization is not obtained for low pulsed field and trapped field is decreased by reversed current in the HTS. The trapped field distribution by repulsed magnetization was previously reported in experiments with temperature control. In this study, repulsed magnetization technique with the low pulsed field is numerically analyzed under assumption of variable shielding current by the temperature control. The shielding current densities are discussed to obtain maximum trapped field by two times of low pulsed field magnetizations

Emergence of amplitude death scenario in a network of oscillators under repulsive delay interaction

Energy Technology Data Exchange (ETDEWEB)

Bera, Bidesh K., E-mail: bideshbera18@gmail.com [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India); Hens, Chittaranjan, E-mail: chittaranjanhens@gmail.com [Department of Mathematics, Bar-Ilan University, Ramat Gan 52900 (Israel); Ghosh, Dibakar, E-mail: dibakar@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India)

2016-07-15

Highlights: • Amplitude death is observed using repulsive mean coupling. • Analytical conditions for amplitude death are derived. • Effect of asymmetry time delay coupling for death is discussed. - Abstract: We report the existence of amplitude death in a network of identical oscillators under repulsive mean coupling. Amplitude death appears in a globally coupled network of identical oscillators with instantaneous repulsive mean coupling only when the number of oscillators is more than two. We further investigate that, amplitude death may emerge even in two coupled oscillators as well as network of oscillators if we introduce delay time in the repulsive mean coupling. We have analytically derived the region of amplitude death island and find out how strength of delay controls the death regime in two coupled or a large network of coupled oscillators. We have verified our results on network of delayed Mackey–Glass systems where parameters are set in hyperchaotic regime. We have also tested our coupling approach in two paradigmatic limit cycle oscillators: Stuart–Landau and Van der Pol oscillators.

Emergence of amplitude death scenario in a network of oscillators under repulsive delay interaction

International Nuclear Information System (INIS)

Bera, Bidesh K.; Hens, Chittaranjan; Ghosh, Dibakar

2016-01-01

Highlights: • Amplitude death is observed using repulsive mean coupling. • Analytical conditions for amplitude death are derived. • Effect of asymmetry time delay coupling for death is discussed. - Abstract: We report the existence of amplitude death in a network of identical oscillators under repulsive mean coupling. Amplitude death appears in a globally coupled network of identical oscillators with instantaneous repulsive mean coupling only when the number of oscillators is more than two. We further investigate that, amplitude death may emerge even in two coupled oscillators as well as network of oscillators if we introduce delay time in the repulsive mean coupling. We have analytically derived the region of amplitude death island and find out how strength of delay controls the death regime in two coupled or a large network of coupled oscillators. We have verified our results on network of delayed Mackey–Glass systems where parameters are set in hyperchaotic regime. We have also tested our coupling approach in two paradigmatic limit cycle oscillators: Stuart–Landau and Van der Pol oscillators.

Synchronous bursts on scale-free neuronal networks with attractive and repulsive coupling.

Directory of Open Access Journals (Sweden)

Qingyun Wang

Full Text Available This paper investigates the dependence of synchronization transitions of bursting oscillations on the information transmission delay over scale-free neuronal networks with attractive and repulsive coupling. It is shown that for both types of coupling, the delay always plays a subtle role in either promoting or impairing synchronization. In particular, depending on the inherent oscillation period of individual neurons, regions of irregular and regular propagating excitatory fronts appear intermittently as the delay increases. These delay-induced synchronization transitions are manifested as well-expressed minima in the measure for spatiotemporal synchrony. For attractive coupling, the minima appear at every integer multiple of the average oscillation period, while for the repulsive coupling, they appear at every odd multiple of the half of the average oscillation period. The obtained results are robust to the variations of the dynamics of individual neurons, the system size, and the neuronal firing type. Hence, they can be used to characterize attractively or repulsively coupled scale-free neuronal networks with delays.

Small-Angle Neutron Scattering Study of Interplay of Attractive and Repulsive Interactions in Nanoparticle-Polymer System.

Science.gov (United States)

Kumar, Sugam; Aswal, Vinod K; Kohlbrecher, Joachim

2016-02-16

The phase behavior of nanoparticle (silica)-polymer (polyethylene glycol) system without and with an electrolyte (NaCl) has been studied. It is observed that nanoparticle-polymer system behaves very differently in the presence of electrolyte. In the absence of electrolyte, the nanoparticle-polymer system remains in one-phase even at very high polymer concentrations. On the other hand, a re-entrant phase behavior is found in the presence of electrolyte, where one-phase (individual) system undergoes two-phase (nanoparticle aggregation) and then back to one-phase with increasing polymer concentration. The regime of two-phase system has been tuned by varying the electrolyte concentration. The polymer concentration range over which the two-phase system exists is significantly enhanced with the increase in the electrolyte concentration. These systems have been characterized by small-angle neutron scattering (SANS) experiments of contrast-marching the polymer to the solvent. The data are modeled using a two-Yukawa potential accounting for both attractive and repulsive parts of the interaction between nanoparticles. The phase behavior of nanoparticle-polymer system is explained by interplay of attractive (polymer-induced attractive depletion between nanoparticles) and repulsive (nanoparticle-nanoparticle electrostatic repulsion and polymer-polymer repulsion) interactions present in the system. In the absence of electrolyte, the strong electrostatic repulsion between nanoparticles dominates over the polymer-induced depletion attraction and the nanoparticle system remains in one-phase. With addition of electrolyte, depletion attraction overcomes electrostatic repulsion at some polymer concentration, resulting into nanoparticle aggregation and two-phase system. Further addition of polymer increases the polymer-polymer repulsion which eventually reduces the strength of depletion and hence re-entrant phase behavior. The effects of varying electrolyte concentration on the phase

Mixed-mode reversed phase/positively charged repulsion chromatography for intact protein separation.

Science.gov (United States)

Ding, Ling; Guo, Zhimou; Hu, Zhuo; Liang, Xinmiao

2017-05-10

A mixed-mode reversed phase/positively charged repulsion stationary phase C8PN composed of octyl and amino group has been developed for separation of intact protein. Before the separation of proteins, a set of probe compounds were employed to evaluate the chromatographic properties of C8PN, demonstrating typical reversed phase/positively charged repulsion interaction on this stationary phase as estimated. Then the new C8PN stationary phase was used to separate a standard protein mixture on the reversed phase mode. Compared with a commercial C4 stationary phase, it showed different selectivity for some proteins. In order to better understand the properties of C8PN, the effect of acetonitrile content was investigated based on retention equation. Higher values of the equation parameters on C8PN demonstrated that the protein retentions were more sensitive to the change of acetonitrile content. Besides, the influences of buffer salt additives on the protein retentions were also studied. The retention factors of the proteins got larger with the increase of buffer salt concentration, which confirmed the positively charged repulsion interaction on the column. Finally, the C8PN was further applied to separate oxidized- and reduced- forms of Recombinant Human Growth Hormone. Our study indicated the advantages and application potential of mixed-mode reversed phase/positively charged repulsion stationary phase for intact protein separation. Copyright © 2017 Elsevier B.V. All rights reserved.

The effects of attractive vs. repulsive instructional cuing on balance performance.

Science.gov (United States)

Kinnaird, Catherine; Lee, Jaehong; Carender, Wendy J; Kabeto, Mohammed; Martin, Bernard; Sienko, Kathleen H

2016-03-16

Torso-based vibrotactile feedback has been shown to improve postural performance during quiet and perturbed stance in healthy young and older adults and individuals with balance impairments. These systems typically include tactors distributed around the torso that are activated when body motion exceeds a predefined threshold. Users are instructed to "move away from the vibration". However, recent studies have shown that in the absence of instructions, vibrotactile stimulation induces small (~1°) non-volitional responses in the direction of its application location. It was hypothesized that an attractive cuing strategy (i.e., "move toward the vibration") could improve postural performance by leveraging this natural tendency. Eight healthy older adults participated in two non-consecutive days of computerized dynamic posturography testing while wearing a vibrotactile feedback system comprised of an inertial measurement unit and four tactors that were activated in pairs when body motion exceeded 1° anteriorly or posteriorly. A crossover design was used. On each day participants performed 24 repetitions of Sensory Organization Test condition 5 (SOT5), three repetitions each of SOT 1-6, three repetitions of the Motor Control Test, and five repetitions of the Adaptation Test. Performance metrics included A/P RMS, Time-in-zone and 95 % CI Ellipse. Performance improved with both cuing strategies but participants performed better when using repulsive cues. However, the rate of improvement was greater for attractive versus repulsive cuing. The results suggest that when the cutaneous signal is interpreted as an alarm, cognition overrides sensory information. Furthermore, although repulsive cues resulted in better performance, attractive cues may be as good, if not better, than repulsive cues following extended training.

Self-accelerated Universe Induced by Repulsive Effects as an Alternative to Dark Energy and Modified Gravities

Science.gov (United States)

Luongo, Orlando; Quevedo, Hernando

2018-01-01

The existence of current-time universe's acceleration is usually modeled by means of two main strategies. The first makes use of a dark energy barotropic fluid entering by hand the energy-momentum tensor of Einstein's theory. The second lies on extending the Hilbert-Einstein action giving rise to the class of extended theories of gravity. In this work, we propose a third approach, derived as an intrinsic geometrical effect of space-time, which provides repulsive regions under certain circumstances. We demonstrate that the effects of repulsive gravity naturally emerge in the field of a homogeneous and isotropic universe. To this end, we use an invariant definition of repulsive gravity based upon the behavior of the curvature eigenvalues. Moreover, we show that repulsive gravity counterbalances the standard gravitational attraction influencing both late and early times of the universe evolution. This phenomenon leads to the present speed up and to the fast expansion due to the inflationary epoch. In so doing, we are able to unify both dark energy and inflation in a single scheme, showing that the universe changes its dynamics when {\\ddot{H}\\over H}=-2 \\dot{H}, at the repulsion onset time where this condition is satisfied. Further, we argue that the spatial scalar curvature can be taken as vanishing because it does not affect at all the emergence of repulsive gravity. We check the goodness of our approach through two cosmological fits involving the most recent union 2.1 supernova compilation.

4-center STO interelectron repulsion integrals with Coulomb Sturmians

DEFF Research Database (Denmark)

Avery, James Emil; Avery, John Scales

2018-01-01

Abstract We present a method for evaluating 4-center electron repulsion integrals (ERI) for Slater-type orbitals by way of expansions in terms of Coulomb Sturmians. The ERIs can then be evaluated using our previously published methods for rapid evaluation of Coulomb Sturmians through hyperspherical...

Minutes of the twelfth INDC meeting, Vienna, 5-9 October 1981

International Nuclear Information System (INIS)

Yiftah, S.

1982-08-01

The Twelfth Meeting of the INDC was held at IAEA Headquarters in Vienna from 5-9 October 1981. The meeting was attended by 13 committee members (member from Australia excused), six advisers and three observers from 14 Member States and two international organisations. The committee reviewed the nuclear data activities of the IAEA, in Member States and in nuclear data centres during the period since its Eleventh Meeting in Vienna in June 1980. It also discussed and reviewed in detail the Agency's future nuclear data programme for the period 1982-84. In general, the IAEA nuclear data programme reflects the trends discussed and detailed at the 11th INDC Meeting. The official minutes include summaries of the discussions of the agenda items, full reports of subcommittees, list of actions, together with lists of participants and subcommittee membership

Mirror nesting and repulsion-induced superconductivity

International Nuclear Information System (INIS)

Belyavsky, Vladimir I.; Kapaev, Vladimir V.; Kopaev, Yurii V.

2004-01-01

Mirror nesting condition that is a rise of pair Fermi contour due to matching of some pieces of the Fermi contour and an isoline of the pair-relative-motion kinetic energy may be satisfied, at definite total pair momenta, due to special features of electron dispersion. Perfect mirror nesting results in a rise of the possibility of superconducting ordering up to arbitrary small pairing repulsive interaction strength. Due to kinematical constraints, the order parameter exists only inside some definite domain of the momentum space and changes its sign on a line belonging to this domain

Nuclear power in the Midwest: proceedings of the twelfth annual Illinois Energy Conference

International Nuclear Information System (INIS)

1984-01-01

Sessions were devoted to: nuclear waste disposal; power plant safety, decommissioning, and waste transportation; economics of nuclear power; and alternatives to nuclear power. Separate abstracts were prepared for 19 papers

Role of repulsive interactions in the interplay with missing strange resonances

Directory of Open Access Journals (Sweden)

Alba Paolo

2018-01-01

Full Text Available The standard implementation of the HRG model has been shown to be unable to describe all the available data on QCD matter. Here we show the balance of repulsive and attractive hadronic interactions on QCD thermodynamics through observables both calculated by lattice simulations and measured in experiment. Attractive interactions are mediated by resonance formation, which are here implemented through extra states predicted by the Quark Model, while repulsive interactions are modelled by means of Excluded Volume (EV effects. Informations on flavour dependent effective sizes are extracted. It is found that EV effects are present in lattice QCD thermodynamics, and are essential for a comprehensive description of higher order fluctuations of conserved charges.

Metastability and coherence of repulsive polarons in a strongly interacting Fermi mixture

DEFF Research Database (Denmark)

Kohstall, Cristoph; Zaccanti, Mattheo; Jag, Matthias

2012-01-01

show that a well-defined quasiparticle exists for strongly repulsive interactions. We measure the energy and the lifetime of this ‘repulsive polaron’9, 12, 13, and probe its coherence properties by measuring the quasiparticle residue. The results are well described by a theoretical approach that takes...... into account the finite effective range of the interaction in our system. We find that when the effective range is of the order of the interparticle spacing, there is a substantial increase in the lifetime of the quasiparticles. The existence of such a long-lived, metastable many-body state offers intriguing...

Mean transverse momenta correlations in hadron-hadron collisions in MC toy model with repulsing strings

International Nuclear Information System (INIS)

Altsybeev, Igor

2016-01-01

In the present work, Monte-Carlo toy model with repulsing quark-gluon strings in hadron-hadron collisions is described. String repulsion creates transverse boosts for the string decay products, giving modifications of observables. As an example, long-range correlations between mean transverse momenta of particles in two observation windows are studied in MC toy simulation of the heavy-ion collisions

Absence of level-repulsion in a two-state Hamiltonian

International Nuclear Information System (INIS)

Ahmed, Zafar

2007-01-01

But for the inclusion of scattering states, we point out that the two-state method (the so called perturbation method of nearly degenerate levels) for a perturbed two-state Hamiltonian is exact , yet the prediction of the level-repulsion by this method could be contradicted by the exact quantal eigenvalues. (author)

WIDM'12 : the proceedings of the twelfth ACM international workshop on Web information and data management, November 2, 2012, Maui, Hawaii, USA

NARCIS (Netherlands)

Fletcher, G.H.L.; Mitra, P.

2012-01-01

We give an overview of WIDM 2012, held in conjunction with CIKM2012 inMaui, Hawaii. WIDM 2012 is the twelfth in a series of international workshops on Web Information and Data Management held in conjunction with CIKM since 1998. The objective of the workshop is to bring together researchers and

Solution structure of the twelfth cysteine-rich ligand-binding repeat in rat megalin

International Nuclear Information System (INIS)

Wolf, Christian A.; Dancea, Felician; Shi Meichen; Bade-Noskova, Veronika; Rueterjans, Heinz; Kerjaschki, Dontscho; Luecke, Christian

2007-01-01

Megalin, an approx. 600 kDa transmembrane glycoprotein that acts as multi-ligand transporter, is a member of the low density lipoprotein receptor gene family. Several cysteine-rich repeats, each consisting of about 40 residues, are responsible for the multispecific binding of ligands. The solution structure of the twelfth cysteine-rich ligand-binding repeat with class A motif found in megalin features two short β-strands and two helical turns, yielding the typical fold with a I-III, II-V and IV-VI disulfide bridge connectivity pattern and a calcium coordination site at the C-terminal end. The resulting differences in electrostatic surface potential compared to other ligand-binding modules of this gene family, however, may be responsible for the functional divergence

Stabilization of thin liquid films by repulsive van der waals force

KAUST Repository

Li, Erqiang

2014-05-13

Using high-speed video recording of bubble rise experiments, we study the stability of thin liquid films trapped between a rising bubble and a surfactant-free liquid-liquid meniscus interface. Using different combinations of nonpolar oils and water that are all immiscible, we investigate the extent to which film stability can be predicted by attractive and repulsive van der Waals (vdW) interactions that are indicated by the relative magnitude of the refractive indices of the liquid combinations, for example, water (refractive index, n = 1.33), perfluorohexane (n = 1.23), and tetradecane (n = 1.43). We show that, when the film-forming phase was oil (perfluorohexane or tetradecane), the stability of the film could always be predicted from the sign of the vdW interaction, with a repulsive vdW force resulting in a stable film and an attractive vdW force resulting in film rupture. However, if aqueous electrolyte is the film-forming bulk phase between the rising air bubble and the upper oil phase, the film always ruptured, even when a repulsive vdW interaction was predicted. We interpret these results as supporting the hypothesis that a short-ranged hydrophobic attraction determines the stability of the thin water film formed between an air phase and a nonpolar oil phase. © 2014 American Chemical Society.

Nuclear many-body problem with repulsive hard core interactions

Energy Technology Data Exchange (ETDEWEB)

Haddad, L M

1965-07-01

The nuclear many-body problem is considered using the perturbation-theoretic approach of Brueckner and collaborators. This approach is outlined with particular attention paid to the graphical representation of the terms in the perturbation expansion. The problem is transformed to centre-of-mass coordinates in configuration space and difficulties involved in ordinary methods of solution of the resulting equation are discussed. A new technique, the 'reference spectrum method', devised by Bethe, Brandow and Petschek in an attempt to simplify the numerical work in presented. The basic equations are derived in this approximation and considering the repulsive hard core part of the interaction only, the effective mass is calculated at high momentum (using the same energy spectrum for both 'particle' and 'hole' states). The result of 0.87m is in agreement with that of Bethe et al. A more complete treatment using the reference spectrum method in introduced and a self-consistent set of equations is established for the reference spectrum parameters again for the case of hard core repulsions. (author)

Social dynamics in emergency evacuations: Disentangling crowd's attraction and repulsion effects

Science.gov (United States)

Haghani, Milad; Sarvi, Majid

2017-06-01

The social dynamics of crowds in emergency escape scenarios have been conventionally modelled as the net effect of virtual forces exerted by the crowd on each individual (as self-driven particles), with the magnitude of the influence formulated as decreasing functions of inter-individual distances and the direction of effect assumed to be transitioning from repulsion to attraction by distance. Here, we revisit this conventional assumption using laboratory experimental data. We show based on robust econometric hypothesis-testing methods that individuals' perception of other escapees differs based on whether those individuals are jamming around exit destinations or are on the move towards the destinations. Also, for moving crowds, it differs based on whether the escape destination chosen by the moving flow is visible or invisible to the individual. The presence of crowd jams around a destination, also the movement of crowd flows towards visible destinations are both perceived on average as repulsion (or disutility) effects (with the former showing significantly larger magnitude than the latter). The movement of crowd flows towards an invisible destination, however, is on average perceived as attraction (or utility) effect. Yet, further hypothesis testing showed that neither of those effects in isolation determines adequately whether an individual would merge with or diverge from the crowd. Rather, the social interaction factors act (at significant levels) in conjunction with the physical factors of the environments (including spatial distances to exit destinations and destinations' visibility). In brief, our finding disentangles the conditions under which individuals are more likely to show mass behaviour from the situations where they are more likely to break from the herd. It identifies two factors that moderate the perception of social interactions, ;crowds' jam/movement status; and ;environmental setup;. Our results particularly challenge the taxonomy of

Regardless-of-Speed Superconducting LSM Controlled-Repulsive MAGLEV Vehicle

Science.gov (United States)

Yoshida, Kinjiro; Egashira, Tatsuya; Hirai, Ryuichi

1996-01-01

This paper proposes a new repulsive Maglev vehicle which a superconducting linear synchronous motor (LSM) can levitate and propel simultaneously, independently of the vehicle speeds. The combined levitation and propulsion control is carried out by controlling mechanical-load angle and armature-current. Dynamic simulations show successful operations with good ride-quality by using a compact control method proposed here.

Proceedings of the twelfth international symposium on remote sensing of environment

Energy Technology Data Exchange (ETDEWEB)

1978-01-01

This is the third of three volumes of the proceedings of the Twelfth International Symposium on Remote Sensing of Environment, held 20 to 26 April 1978 in Manila, Philippines. This symposium is part of a continuing program investigating current activities in the field of remote sensing. The meeting is intended to promote increased international cooperation in research, development and application of this technology, and to stimulate an exchange of information on all aspects of this multidisciplinary field through the presentation of reports on work planned, in progress or completed. Presentations include those concerned with the utilization of this technology in various national and international programs as well as in numerous applications for monitoring and managing the earth's resources and man's global environment. Ground-based, airborne, and spaceborne sensor systems and both manual and machine-assisted data analysis and interpretation are included. All papers included in their entirety were abstracted and indexed for EDB/ERA.

Analysis on Patterns of Globally Coupled Phase Oscillators with Attractive and Repulsive Interactions

International Nuclear Information System (INIS)

Wang Peng-Fei; Xu Zhong-Bin; Ruan Xiao-Dong; Fu Xin

2015-01-01

The Hong–Strogatz (HS) model of globally coupled phase oscillators with attractive and repulsive interactions reflects the fact that each individual (oscillator) has its own attitude (attractive or repulsive) to the same environment (mean field). Previous studies on HS model focused mainly on the stable states on Ott–Antonsen (OA) manifold. In this paper, the eigenvalues of the Jacobi matrix of each fixed point in HS model are explicitly derived, with the aim to understand the local dynamics around each fixed point. Phase transitions are described according to relative population and coupling strength. Besides, the dynamics off OA manifold is studied. (paper)

Density-Dependent Formulation of Dispersion-Repulsion Interactions in Hybrid Multiscale Quantum/Molecular Mechanics (QM/MM) Models

DEFF Research Database (Denmark)

Curutchet, Carles; Cupellini, Lorenzo; Kongsted, Jacob

2018-01-01

embedding approaches, respectively, nonelectrostatic dispersion and repulsion interactions are instead commonly described through classical potentials despite their quantum mechanical origin. Here we present an extension of the Tkatchenko-Scheffler semiempirical van der Waals (vdWTS) scheme aimed......Mixed multiscale quantum/molecular mechanics (QM/MM) models are widely used to explore the structure, reactivity, and electronic properties of complex chemical systems. Whereas such models typically include electrostatics and potentially polarization in so-called electrostatic and polarizable...... at describing dispersion and repulsion interactions between quantum and classical regions within a QM/MM polarizable embedding framework. Starting from the vdWTSexpression, we define a dispersion and a repulsion term, both of them density-dependent and consistently based on a Lennard-Jones-like potential. We...

DE TESTIBUS TRACTATURI: A LATE TWELFTH-CENTURY ITALIAN CANONISTIC TREATISE ON LEGAL PROCEDURE

Directory of Open Access Journals (Sweden)

Bruce C. Brasington

2017-06-01

Full Text Available De testibus tractaturi, an unedited late twelfth-century, southern Italian treatise, draws on both Gratian’s Decretum and decretals of Pope Alexander III to consider question concerning witnesses. It may also be influenced to some degree by the Summa of Simon of Bisignano. There is no evidence of any reliance on civilian authors. In considering the exceptio contra personam testis, it raises the question of whether testimony given by a witness who later died before trial remained valid. This subject is rarely treated in the early canonistic ordines iudiciorum. The author’s application of a letter of Alexander III to Bishop Roger of Worchester (JL 13162 to this question appears to be unusual, perhaps unique, and sheds light on how the early ius commune evaluated evidence.

New laser power sensor using weighing method

Science.gov (United States)

Pinot, P.; Silvestri, Z.

2018-01-01

We present a set-up using a piece of pyrolytic carbon (PyC) to measure laser power in the range from a few milliwatts to a few watts. The experimental configuration consists in measuring the magnetic repulsion force acting between a piece of PyC placed on a weighing pan and in a magnetic induction generated by a magnet array in a fixed position above the PyC sheet. This involves a repulsion force on the PyC piece which is expressed in terms of mass by the balance display. The quantities affecting the measurement results have been identified. An example of metrological characterization in terms of accuracy, linearity and sensitivity is given. A relative uncertainty of optical power measurement for the first experimental set-up is around 1%. The wavelength and power density dependence on power response of this device has been demonstrated. This PyC-based device presented here in weighing configuration and the other one previously studied in levitation configuration offer a new technique for measuring optical power.

Dissecting Repulsive Guidance Molecule/Neogenin function and signaling during neural development

NARCIS (Netherlands)

van den Heuvel, D.M.A.

2013-01-01

During neural development a series of precisely ordered cellular processes acts to establish a functional brain comprising millions of neurons and many more neuronal connections. Neogenin and its repulsive guidance molecule (RGM) ligands contribute to neuronal network formation by inducing axon

Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional

OpenAIRE

Joubert, Daniel P.

2011-01-01

The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.

Eleventh ITER negotiations meeting (N-11) and twelfth negotiators' standing sub-group meeting (NSSG-12)

International Nuclear Information System (INIS)

Luo Delong

2005-01-01

The Eleventh ITER Negotiations Meeting (N-11) and the Twelfth Negotiators' Standing Sub-Group (NSSG-12 convened on October 19-25, 2005 at the Kempinski Hotel Chengdu, Sichuan Province. China was the host of this meeting. Delegations from China, the European Union, Japan, the Republic of Korea, the Russian Federation and the United States of America, as well as members from the International Team, met there to continue their work to reach agreement on the joint implementation of the ITER international fusion energy R and D project. The delegations accepted the Vice Minister of Science and Technology, Mr. LIU Yanhua, and State Councillor, Mr. SHI Dinghuan as Moderators for N-11 and NSSG-12, respectively, and Mr. LUO Delong as Secretary for both meetings. At the Meeting, delegates discussed and made substantial progress on a full range of legal, technical, and administrative topics, including staffing for ITER, policies for managing the project and its procurements, and the continuing joint drafting of the agreement on establishing the international ITER Organization to implement the project. Delegates also explored the possibility of India joining the Negotiations. In the light of the reports presented to the Meeting from the recent joint exploratory mission to India, delegates identified a series of steps for the near future leading towards a possible agreement among all the Parties to India's accession. The Negotiations Meeting also discussed the progress report of NSSG and forward planning and future tasks. The Negotiators agreed that substantial progress was made on all topics, and delegations are optimistic that the Joint Implementation Agreement and related Annexes and instruments could be initialed in spring of 2006. As decided by all delegations, the next Twelfth ITER Negotiations Meeting will be held in Korea on 6 December, 2005

Comment on ;Acceleration of particles to high energy via gravitational repulsion in the Schwarzschild field; [Astropart. Phys. 86 (2017) 18-20

Science.gov (United States)

Spallicci, Alessandro D. A. M.

2017-09-01

Comments are due on a recent paper by McGruder III (2017) in which the author deals with the concept of gravitational repulsion in the context of the Schwarzschild-Droste solution. Repulsion (deceleration) for ingoing particles into a black hole is a concept proposed several times starting from Droste himself in 1916. It is a coordinate effect appearing to an observer at a remote distance from the black hole and when coordinate time is employed. Repulsion has no bearing and relation to the local physics of the black hole, and moreover it cannot be held responsible for accelerating outgoing particles. Thereby, the energy boost of cosmic rays cannot be produced by repulsion.

Repulsive effects of hydrophobic diamond thin films on biomolecule detection

Energy Technology Data Exchange (ETDEWEB)

Ruslinda, A. Rahim, E-mail: ruslindarahim@gmail.com [Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, Jln Kgr-Alor Setar, Seriab, 01000 Kangar, Perlis (Malaysia); Department of Nano Science and Nano Engineering, School of Advance Science and Engineering, Ohkubo 3-4-1, Shinjuku, 169-8555 Tokyo (Japan); Ishiyama, Y. [Department of Nano Science and Nano Engineering, School of Advance Science and Engineering, Ohkubo 3-4-1, Shinjuku, 169-8555 Tokyo (Japan); Penmatsa, V. [Department of Mechanical and Materials Engineering, Florida International University, 10555 West Flagler Street, Miami, FL 33174 (United States); Ibori, S.; Kawarada, H. [Department of Nano Science and Nano Engineering, School of Advance Science and Engineering, Ohkubo 3-4-1, Shinjuku, 169-8555 Tokyo (Japan)

2015-02-15

Highlights: • We report the effect of fluorine plasma treatment on diamond thin film to resist the nonspecific adsorption of biomolecules. • The diamond thin film were highly hydrophobic with a surface energy value of ∼25 mN/m. • The repulsive effect shows excellent binding efficiency for both DNA and HIV-1 Tat protein. - Abstract: The repulsive effect of hydrophobic diamond thin film on biomolecule detection, such as single-nucleotide polymorphisms and human immunodeficiency virus type 1 trans-activator of transcription peptide protein detection, was investigated using a mixture of a fluorine-, amine-, and hydrogen-terminated diamond surfaces. These chemical modifications lead to the formation of a surface that effectively resists the nonspecific adsorption of proteins and other biomolecules. The effect of fluorine plasma treatment on elemental composition was also investigated via X-ray photoelectron spectroscopy (XPS). XPS results revealed a fluorocarbon layer on the diamond thin films. The contact angle measurement results indicated that the fluorine-treated diamond thin films were highly hydrophobic with a surface energy value of ∼25 mN/m.

Repulsive effects of hydrophobic diamond thin films on biomolecule detection

International Nuclear Information System (INIS)

Ruslinda, A. Rahim; Ishiyama, Y.; Penmatsa, V.; Ibori, S.; Kawarada, H.

2015-01-01

Highlights: • We report the effect of fluorine plasma treatment on diamond thin film to resist the nonspecific adsorption of biomolecules. • The diamond thin film were highly hydrophobic with a surface energy value of ∼25 mN/m. • The repulsive effect shows excellent binding efficiency for both DNA and HIV-1 Tat protein. - Abstract: The repulsive effect of hydrophobic diamond thin film on biomolecule detection, such as single-nucleotide polymorphisms and human immunodeficiency virus type 1 trans-activator of transcription peptide protein detection, was investigated using a mixture of a fluorine-, amine-, and hydrogen-terminated diamond surfaces. These chemical modifications lead to the formation of a surface that effectively resists the nonspecific adsorption of proteins and other biomolecules. The effect of fluorine plasma treatment on elemental composition was also investigated via X-ray photoelectron spectroscopy (XPS). XPS results revealed a fluorocarbon layer on the diamond thin films. The contact angle measurement results indicated that the fluorine-treated diamond thin films were highly hydrophobic with a surface energy value of ∼25 mN/m

Lefschetz thimbles in fermionic effective models with repulsive vector-field

Science.gov (United States)

Mori, Yuto; Kashiwa, Kouji; Ohnishi, Akira

2018-06-01

We discuss two problems in complexified auxiliary fields in fermionic effective models, the auxiliary sign problem associated with the repulsive vector-field and the choice of the cut for the scalar field appearing from the logarithmic function. In the fermionic effective models with attractive scalar and repulsive vector-type interaction, the auxiliary scalar and vector fields appear in the path integral after the bosonization of fermion bilinears. When we make the path integral well-defined by the Wick rotation of the vector field, the oscillating Boltzmann weight appears in the partition function. This "auxiliary" sign problem can be solved by using the Lefschetz-thimble path-integral method, where the integration path is constructed in the complex plane. Another serious obstacle in the numerical construction of Lefschetz thimbles is caused by singular points and cuts induced by multivalued functions of the complexified scalar field in the momentum integration. We propose a new prescription which fixes gradient flow trajectories on the same Riemann sheet in the flow evolution by performing the momentum integration in the complex domain.

Construction and Self-Assembly of Single-Chain Polymer Nanoparticles via Coordination Association and Electrostatic Repulsion in Water.

Science.gov (United States)

Zhu, Zhengguang; Xu, Na; Yu, Qiuping; Guo, Lei; Cao, Hui; Lu, Xinhua; Cai, Yuanli

2015-08-01

Simultaneous coordination-association and electrostatic-repulsion interactions play critical roles in the construction and stabilization of enzymatic function metal centers in water media. These interactions are promising for construction and self-assembly of artificial aqueous polymer single-chain nanoparticles (SCNPs). Herein, the construction and self-assembly of dative-bonded aqueous SCNPs are reported via simultaneous coordination-association and electrostatic-repulsion interactions within single chains of histamine-based hydrophilic block copolymer. The electrostatic-repulsion interactions are tunable through adjusting the imidazolium/imidazole ratio in response to pH, and in situ Cu(II)-coordination leads to the intramolecular association and single-chain collapse in acidic water. SCNPs are stabilized by the electrostatic repulsion of dative-bonded block and steric shielding of nonionic water-soluble block, and have a huge specific surface area of function metal centers accessible to substrates in acidic water. Moreover, SCNPs can assemble into micelles, networks, and large particles programmably in response to the solution pH. These unique media-sensitive phase-transformation behaviors provide a general, facile, and versatile platform for the fabrication of enzyme-inspired smart aqueous catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pattern formation in annular systems of repulsive particles

DEFF Research Database (Denmark)

Marschler, Christian; Starke, Jens; Sørensen, Mads Peter

2016-01-01

General particle models with symmetric and asymmetric repulsion are studied and investigated for finite-range and exponential interaction in an annulus. In the symmetric case transitions from one- to multi-lane behavior including multistability are observed for varying particle density and for a ...... and for a varying curvature with fixed density. Hence, the system cannot be approximated by a periodic channel. In the asymmetric case, which is important in pedestrian dynamics, we reveal an inhomogeneous new phase, a traveling wave reminiscent of peristaltic motion....

Density-Dependent Formulation of Dispersion-Repulsion Interactions in Hybrid Multiscale Quantum/Molecular Mechanics (QM/MM) Models.

Science.gov (United States)

Curutchet, Carles; Cupellini, Lorenzo; Kongsted, Jacob; Corni, Stefano; Frediani, Luca; Steindal, Arnfinn Hykkerud; Guido, Ciro A; Scalmani, Giovanni; Mennucci, Benedetta

2018-03-13

Mixed multiscale quantum/molecular mechanics (QM/MM) models are widely used to explore the structure, reactivity, and electronic properties of complex chemical systems. Whereas such models typically include electrostatics and potentially polarization in so-called electrostatic and polarizable embedding approaches, respectively, nonelectrostatic dispersion and repulsion interactions are instead commonly described through classical potentials despite their quantum mechanical origin. Here we present an extension of the Tkatchenko-Scheffler semiempirical van der Waals (vdW TS ) scheme aimed at describing dispersion and repulsion interactions between quantum and classical regions within a QM/MM polarizable embedding framework. Starting from the vdW TS expression, we define a dispersion and a repulsion term, both of them density-dependent and consistently based on a Lennard-Jones-like potential. We explore transferable atom type-based parametrization strategies for the MM parameters, based on either vdW TS calculations performed on isolated fragments or on a direct estimation of the parameters from atomic polarizabilities taken from a polarizable force field. We investigate the performance of the implementation by computing self-consistent interaction energies for the S22 benchmark set, designed to represent typical noncovalent interactions in biological systems, in both equilibrium and out-of-equilibrium geometries. Overall, our results suggest that the present implementation is a promising strategy to include dispersion and repulsion in multiscale QM/MM models incorporating their explicit dependence on the electronic density.

Stability of a fully magnetized ferromagnetic state in repulsively interacting ultracold Fermi gases

International Nuclear Information System (INIS)

Cui Xiaoling; Zhai Hui

2010-01-01

We construct a variational wave function to study whether a fully polarized Fermi sea of ultracold atoms is energetically stable against a single spin flip. Our variational wave function contains short-range correlations at least to the same level as Gutzwiller's projected wave function. For the Hubbard lattice model and the continuum model with pure repulsive interaction, we show that a fully polarized Fermi sea is generally unstable even for infinite repulsive strength. By contrast, for a resonance model, the ferromagnetic state is possible if the s-wave scattering length is positive and sufficiently large and the system is prepared to be orthogonal to the molecular bound state. However, we cannot rule out the possibility that more exotic correlations can destabilize the ferromagnetic state.

From repulsive to attractive glass: A rheological investigation.

Science.gov (United States)

Zhou, Zhi; Jia, Di; Hollingsworth, Javoris V; Cheng, He; Han, Charles C

2015-12-21

Linear rheological properties and yielding behavior of polystyrene core and poly (N-isopropylacrylamide) (PNIPAM) shell microgels were investigated to understand the transition from repulsive glass (RG) to attractive glass (AG) and the A3 singularity. Due to the volume phase transition of PNIPAM in aqueous solution, the microgel-microgel interaction potential gradually changes from repulsive to attractive. In temperature and frequency sweep experiments, the storage modulus (G') and loss modulus (G″) increased discontinuously when crossing the RG-to-AG transition line, while G' at low frequency exhibited a different volume fraction (Φ) dependence. By fitting the data of RG and AG, and then extrapolating to high volume fraction, the difference between RG and AG decreased and the existence of A3 singularity was verified. Dynamic strain sweep experiments were conducted to confirm these findings. RG at 25 °C exhibited one-step yielding, whereas AG at 40 °C showed a typical two-step yielding behavior; the first yielding strain remained constant and the second one gradually decreased as the volume fraction increased. By extrapolating the second yield strain to that of the first one, the predicted A3 singularity was at 0.61 ± 0.02. At 37 °C, when Φeff = 0.59, AG showed one step yielding as the length of the attractive bond increased. The consistency and agreement of the experimental results reaffirmed the existence of A3 singularity, where the yielding behavior of RG and AG became identical.

Horizontal vectorization of electron repulsion integrals.

Science.gov (United States)

Pritchard, Benjamin P; Chow, Edmond

2016-10-30

We present an efficient implementation of the Obara-Saika algorithm for the computation of electron repulsion integrals that utilizes vector intrinsics to calculate several primitive integrals concurrently in a SIMD vector. Initial benchmarks display a 2-4 times speedup with AVX instructions over comparable scalar code, depending on the basis set. Speedup over scalar code is found to be sensitive to the level of contraction of the basis set, and is best for (lAlB|lClD) quartets when lD  = 0 or lB=lD=0, which makes such a vectorization scheme particularly suitable for density fitting. The basic Obara-Saika algorithm, how it is vectorized, and the performance bottlenecks are analyzed and discussed. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A repulsive magnetic force driven translation micromirror

International Nuclear Information System (INIS)

Xue, Yuan; Zuo, Hui; He, Siyuan

2017-01-01

This paper presents a repulsive magnetic force driven micromirror with large displacement and high surface quality which well solves the limitation of the previous design, i.e. large variation in translation starting position and low repeatability, caused by the touching points between the moving film and substrate before and in operation. The new design utilizes a driving mechanism, i.e. permanent magnet ring above and electromagnet underneath the moving film, to lift the moving film from touching the substrate and generate a repulsive magnetic force (instead of attractive force in the previous design) to push the moving film up and away from the substrate for translation. Due to the touching, the previous design has to pre-oscillate for 20–30 min at 1 Hz before usage (after resting for a few hours) to reduce the starting position variation from ∼15 µ m to 3–4 µ m. Even after the pre-oscillation, the repeatability is still low, which is 14.2% because of the touching in operation. In the design presented in this paper, the touching between the moving film and the substrate is completely eliminated before and in operation. As a result, the starting position of the translating mirror is constant each time and the repeatability is  <1%. In addition, this design does not need the residual stress gradient to curve up the moving film. The maximum displacement of 144 µ m can be achieved when 140 mA current is applied on the electromagnet. As an application, the micromirror is used as the movable mirror in a Michelson interferometer to measure the wavelength of a laser beam. The result shows a measurement accuracy of 2.19% for a 532 nm laser beam. (paper)

A repulsive magnetic force driven translation micromirror

Science.gov (United States)

Xue, Yuan; Zuo, Hui; He, Siyuan

2017-10-01

This paper presents a repulsive magnetic force driven micromirror with large displacement and high surface quality which well solves the limitation of the previous design, i.e. large variation in translation starting position and low repeatability, caused by the touching points between the moving film and substrate before and in operation. The new design utilizes a driving mechanism, i.e. permanent magnet ring above and electromagnet underneath the moving film, to lift the moving film from touching the substrate and generate a repulsive magnetic force (instead of attractive force in the previous design) to push the moving film up and away from the substrate for translation. Due to the touching, the previous design has to pre-oscillate for 20-30 min at 1 Hz before usage (after resting for a few hours) to reduce the starting position variation from ~15 µm to 3-4 µm. Even after the pre-oscillation, the repeatability is still low, which is 14.2% because of the touching in operation. In the design presented in this paper, the touching between the moving film and the substrate is completely eliminated before and in operation. As a result, the starting position of the translating mirror is constant each time and the repeatability is  <1%. In addition, this design does not need the residual stress gradient to curve up the moving film. The maximum displacement of 144 µm can be achieved when 140 mA current is applied on the electromagnet. As an application, the micromirror is used as the movable mirror in a Michelson interferometer to measure the wavelength of a laser beam. The result shows a measurement accuracy of 2.19% for a 532 nm laser beam.

Thermodynamics and elastic moduli of fluids with steeply repulsive potentials

Science.gov (United States)

Heyes, D. M.

1997-08-01

Analytic expressions for the thermodynamic properties and elastic moduli of molecular fluids interacting with steeply repulsive potentials are derived using Rowlinson's hard-sphere perturbation treatment which employs a softness parameter, λ specifying the deviation from the hard-sphere potential. Generic potentials of this form might be used to represent the interactions between near-hard-sphere stabilized colloids. Analytic expressions for the equivalent hard-sphere diameter of inverse power [ɛ(σ/r)n where ɛ sets the energy scale and σ the distance scale] exponential and logarithmic potential forms are derived using the Barker-Henderson formula. The internal energies in the hard-sphere limit are predicted essentially exactly by the perturbation approach when compared against molecular dynamics simulation data using the same potentials. The elastic moduli are similarly accurately predicted in the hard-sphere limit, as they are trivially related to the internal energy. The compressibility factors from the perturbation expansion do not compare as favorably with simulation data, and in this case the Carnahan-Starling equation of state prediction using the analytic effective hard-sphere diameter would appear to be a preferable route for this thermodynamic property. A more refined state point dependent definition for the effective hard-sphere diameter is probably required for this property.

Holographic repulsion and confinement in gauge theory

Science.gov (United States)

Husain, Viqar; Kothawala, Dawood

2013-02-01

We show that for asymptotically anti-de Sitter (AdS) backgrounds with negative energy, such as the AdS soliton and regulated negative-mass AdS-Schwarzshild metrics, the Wilson loop expectation value in the AdS/CFT conjecture exhibits a Coulomb to confinement transition. We also show that the quark-antiquark (q \\bar{q}) potential can be interpreted as affine time along null geodesics on the minimal string worldsheet and that its intrinsic curvature provides a signature of transition to confinement phase. Our results suggest a generic (holographic) relationship between confinement in gauge theory and repulsive gravity, which in turn is connected with singularity avoidance in quantum gravity. Communicated by P R L V Moniz

Decay modes of two repulsively interacting bosons

International Nuclear Information System (INIS)

Kim, Sungyun; Brand, Joachim

2011-01-01

We study the decay of two repulsively interacting bosons tunnelling through a delta potential barrier by a direct numerical solution of the time-dependent Schroedinger equation. The solutions are analysed according to the regions of particle presence: both particles inside the trap (in-in), one particle in and one particle out (in-out) and both particles outside (out-out). It is shown that the in-in probability is dominated by the exponential decay, and its decay rate is predicted very well from outgoing boundary conditions. Up to a certain range of interaction strength, the decay of in-out probability is dominated by the single-particle decay mode. The decay mechanisms are adequately described by simple models.

Attractive and repulsive cracks in a heterogeneous material

International Nuclear Information System (INIS)

Cortet, Pierre-Philippe; Huillard, Guillaume; Vanel, Loïc; Ciliberto, Sergio

2008-01-01

We study experimentally the paths of an assembly of cracks growing in interaction in a heterogeneous two-dimensional elastic brittle material submitted to uniaxial stress. For a given initial crack assembly geometry, we observe two types of crack path. The first one corresponds to a repulsion followed by an attraction on one end of the crack and a tip-to-tip attraction on the other end. The second one corresponds to a pure attraction. Only one of the crack path types is observed in a given sample. Thus, selection between the two types appears as a statistical collective process

Minutes of the Twelfth LWR pressure vessel surveillance dosimtery improvement program meeting

International Nuclear Information System (INIS)

1989-01-01

The 1983 Twelfth Light Water Reactor Pressure Vessel Surveillance Dosimetry Improvement Program (LWR-PV-SDIP) Meeting, which was held October 24-28, 1983. Sections 1 through 14 of this report provide documentation of agreements, commitments, and reports that are subject to the approval and concurrence of the participating laboratories and supporting agencies and organizations. Attachment No. 1 provides information on the preparation of a number of NUREG publications that will document the results of various aspects of the LWR-PV-SDIP. For each NUREG publication, a tentative ''Table of Contents'' is provided in addition to suggested interlaboratory writing assignments and camera-ready copy contribution due dates, as appropriate. Attachment No. 2 provides information on planning for the Fifth ASTM-EURATOM Symposium. Attachment No. 3 provides information on an ASTM press release about an MPC-6 meeting and dpa and E > 1 MeV exposure parameters. Attachments No. 4 and 5 provide copies of two LWR-PV-SDIP related papers presented at the Eleventh WRSR Information Meeting, October 24-28, 1983

Repulsive wall potentials for He-(Ne,Ar,Kr,Xe) as inferred from differential cross sections

International Nuclear Information System (INIS)

Nitz, D.E.; Larson, J.; Swanson, K.; Wildgoose, C.

1993-01-01

We have obtained representations of the He-(Ne,Ar,Kr,Xe) ground state repulsive walls using model potentials optimized to fit published absolute differential cross section data for 500 and 1500 eV collisions. The HeNe potential, like the He 2 potentials can be fit using the semi-empirical HFD-B form constrained to cross zero at the proper internuclear separation. For the heavier atoms, this approach is unsuccessful and superior fits are obtained using only the purely repulsive V(r) - A EXP [-αr - βr 2 ] term of the HFD-B potential. Comparison of fitted potentials with previous results will be presented

Role of electrostatic repulsion on colloidal stability of Bacillus halmapalus alpha-amylase

DEFF Research Database (Denmark)

Olsen, Søren Nymand; Andersen, Kim Bruno; Randolf, Theodor

2009-01-01

Bacillus halmapalus α-amylase (BHA) as a model protein. Repulsive forces between partly unfolded monomers were shown to strongly affect aggregation. Adding salt, increasing valence of counter ions or decreasing pH in the direction of pI resulted in a shift in the rate-limiting step from association...

Interaction potential and repulsive force between atoms whose internuclear separations are small

International Nuclear Information System (INIS)

Barbaro, Jacques

1971-01-01

The Thomas-Fermi equation is solved for the homonuclear diatomic molecule. The electronic density and electrostatic potential at each point are used to calculate energies and interaction potentials for very small internuclear separation distances. The repulsive force between atoms is derived by means of the virial theorem. (author) [fr

Measuring the effects of Coulomb repulsion via signal decay in an atmospheric pressure laser ionization ion mobility spectrometer.

Science.gov (United States)

Ihlenborg, Marvin; Schuster, Ann-Kathrin; Grotemeyer, Juergen; Gunzer, Frank

2018-01-01

Using lasers in ion mobility spectrometry offers a lot of advantages compared to standard ionization sources. Especially, the ion yield can be drastically increased. It can, however, reach levels where the Coulomb repulsion leads to unwanted side effects. Here, we investigate how the Coulomb repulsion can be detected apart from the typical signal broadening by measuring effects created already in the reaction region and comparing them with corresponding finite element method simulations.

Separating the effects of repulsive and attractive forces on the phase diagram, interfacial, and critical properties of simple fluids.

Science.gov (United States)

Fuentes-Herrera, M; Moreno-Razo, J A; Guzmán, O; López-Lemus, J; Ibarra-Tandi, B

2016-06-07

Molecular simulations in the canonical and isothermal-isobaric ensembles were performed to study the effect of varying the shape of the intermolecular potential on the phase diagram, critical, and interfacial properties of model fluids. The molecular interactions were modeled by the Approximate Non-Conformal (ANC) theory potentials. Unlike the Lennard-Jones or Morse potentials, the ANC interactions incorporate parameters (called softnesses) that modulate the steepness of the potential in their repulsive and attractive parts independently. This feature allowed us to separate unambiguously the role of each region of the potential on setting the thermophysical properties. In particular, we found positive linear correlation between all critical coordinates and the attractive and repulsive softness, except for the critical density and the attractive softness which are negatively correlated. Moreover, we found that the physical properties related to phase coexistence (such as span of the liquid phase between the critical and triple points, variations in the P-T vaporization curve, interface width, and surface tension) are more sensitive to changes in the attractive softness than to the repulsive one. Understanding the different roles of attractive and repulsive forces on phase coexistence may contribute to developing more accurate models of liquids and their mixtures.

A microelectrostatic repulsive-torque rotation actuator with two-width fingers

International Nuclear Information System (INIS)

Fan, Chao; He, Siyuan

2015-01-01

A microelectrostatic repulsive-torque rotation actuator with two-width fingers is presented. The actuator consists of finger-shaped electrodes and is made of two thin film layers, i.e. one movable layer and one fixed layer. There are two types of finger electrodes, namely constant-width and two-width fingers. The two-width finger has a narrow lower segment and a wide top segment. The constant-width finger has only the narrow lower segment. Each rotation finger has its corresponding aligned and unaligned fixed fingers. The electrostatic repulsive torque is generated and acts on the rotation fingers to rotate them up and away from the substrate. As a result, rotation is not limited by the gap between the movable and fixed layers and the ‘pull-in’ instability is avoided. Thus a large out-of-plane rotation and high operational stability can be achieved. The actuator is suitable for two-layer surface micromachining. The model of the actuator is developed. Prototypes are fabricated and tested. The experimental tests show that the actuator achieved a mechanical rotation of 7.65° at a driving voltage of 150 V. The settling time for a mechanical rotation of 5° is 5.7 ms. (paper)

Swarming and Pattern Formation due to Selective Attraction and Repulsion

OpenAIRE

Romanczuk, Pawel; Schimansky-Geier, Lutz

2012-01-01

We discuss the collective dynamics of self-propelled particles with selective attraction and repulsion interactions. Each particle, or individual, may respond differently to its neighbours depending on the sign of their relative velocity. Thus, it is able to distinguish approaching (coming closer) and retreating (moving away) individuals. This differentiation of the social response is motivated by the response to looming visual stimuli and may be seen as a generalization of the previously pro...

Analysis on Patterns of Globally Coupled Phase Oscillators with Attractive and Repulsive Interactions

Science.gov (United States)

Wang, Peng-Fei; Ruan, Xiao-Dong; Xu, Zhong-Bin; Fu, Xin

2015-11-01

The Hong-Strogatz (HS) model of globally coupled phase oscillators with attractive and repulsive interactions reflects the fact that each individual (oscillator) has its own attitude (attractive or repulsive) to the same environment (mean field). Previous studies on HS model focused mainly on the stable states on Ott-Antonsen (OA) manifold. In this paper, the eigenvalues of the Jacobi matrix of each fixed point in HS model are explicitly derived, with the aim to understand the local dynamics around each fixed point. Phase transitions are described according to relative population and coupling strength. Besides, the dynamics off OA manifold is studied. Supported by the National Basic Research Program of China under Grant No. 2015CB057301, the Applied Research Project of Public Welfare Technology of Zhejiang Province under Grant No. 201SC31109 and China Postdoctoral Science Foundation under Grant No. 2014M560483

Design of 118 MHz twelfth harmonic cavity of APS PAR

International Nuclear Information System (INIS)

Kang, Y.W.; Kustom, R.L.; Bridges, J.F.

1992-01-01

Two radio frequency (RF) cavities are needed in the Positron Accumulator Ring (PAR) of the Advanced Photon Source. One is for the first harmonic frequency at 9.8 MHz, and the other is for the twelfth harmonic frequency at 118 MHz. This note reports on the design of the 118 MHz RF cavity. Computer models are used to find the mode frequencies, impedances, Q-factors, and field distributions in the cavity. The computer codes MAFIA, URMEL, and URMEL-T are useful tools which model and simulate the resonance characteristics of a cavity. These codes employ the finite difference method to solve Maxwell's equations. MAFIA is a three-dimensional problem solver and uses square patches to approximate the inner surface of a cavity. URMEL and URMEL-T are two-dimensional problem solvers and use rectangular and triangular meshes, respectively. URMEL-T and MAFIA can handle problems with arbitrary dielectric materials located inside the boundary. The cavity employs a circularly cylindrical ceramic window to limit the vacuum to the beam pipe. The ceramic window used in the modeling will have a wall thickness of 0.9 cm. This wall thickness is not negligible in determining the resonant frequencies of the cavity. In the following, results of two- and three-dimensional modeling of the cavities using the URMEL-T and MAFIA codes are reported

The chessgame: image, power and the church (late tenth-early twelfth century

Directory of Open Access Journals (Sweden)

Philippe Cordez

2011-12-01

Full Text Available The original in the East, the chessgame was adapted to the Western social and military realities since the tenth century. The codes for the exercise of feudal power were symbolized through the manipulation of its pieces. The analysis of four outside the realm of the chessgame, in the churches of Münster, Aachen, Saint-Denis and Reims, underlines the contribution of chess for the definition of the German Empire and of the French Kingdom.

Slit stimulation recruits Dock and Pak to the roundabout receptor and increases Rac activity to regulate axon repulsion at the CNS midline.

Science.gov (United States)

Fan, Xueping; Labrador, Juan Pablo; Hing, Huey; Bashaw, Greg J

2003-09-25

Drosophila Roundabout (Robo) is the founding member of a conserved family of repulsive axon guidance receptors that respond to secreted Slit proteins. Here we present evidence that the SH3-SH2 adaptor protein Dreadlocks (Dock), the p21-activated serine-threonine kinase (Pak), and the Rac1/Rac2/Mtl small GTPases can function during Robo repulsion. Loss-of-function and genetic interaction experiments suggest that limiting the function of Dock, Pak, or Rac partially disrupts Robo repulsion. In addition, Dock can directly bind to Robo's cytoplasmic domain, and the association of Dock and Robo is enhanced by stimulation with Slit. Furthermore, Slit stimulation can recruit a complex of Dock and Pak to the Robo receptor and trigger an increase in Rac1 activity. These results provide a direct physical link between the Robo receptor and an important cytoskeletal regulatory protein complex and suggest that Rac can function in both attractive and repulsive axon guidance.

Swarming and pattern formation due to selective attraction and repulsion.

Science.gov (United States)

Romanczuk, Pawel; Schimansky-Geier, Lutz

2012-12-06

We discuss the collective dynamics of self-propelled particles with selective attraction and repulsion interactions. Each particle, or individual, may respond differently to its neighbours depending on the sign of their relative velocity. Thus, it is able to distinguish approaching (coming closer) and retreating (moving away) individuals. This differentiation of the social response is motivated by the response to looming visual stimuli and may be seen as a generalization of the previously proposed escape and pursuit interactions motivated by empirical evidence for cannibalism as a driving force of collective migration in locusts and Mormon crickets. The model can account for different types of behaviour such as pure attraction, pure repulsion or escape and pursuit, depending on the values (signs) of the different response strengths. It provides, in the light of recent experimental results, an interesting alternative to previously proposed models of collective motion with an explicit velocity-alignment interaction. We discuss the derivation of a coarse-grained description of the system dynamics, which allows us to derive analytically the necessary condition for emergence of collective motion. Furthermore, we analyse systematically the onset of collective motion and clustering in numerical simulations of the model for varying interaction strengths. We show that collective motion arises only in a subregion of the parameter space, which is consistent with the analytical prediction and corresponds to an effective escape and/or pursuit response.

Gravitational waves during inflation from a 5D large-scale repulsive gravity model

International Nuclear Information System (INIS)

Reyes, Luz M.; Moreno, Claudia; Madriz Aguilar, José Edgar; Bellini, Mauricio

2012-01-01

We investigate, in the transverse traceless (TT) gauge, the generation of the relic background of gravitational waves, generated during the early inflationary stage, on the framework of a large-scale repulsive gravity model. We calculate the spectrum of the tensor metric fluctuations of an effective 4D Schwarzschild-de Sitter metric on cosmological scales. This metric is obtained after implementing a planar coordinate transformation on a 5D Ricci-flat metric solution, in the context of a non-compact Kaluza-Klein theory of gravity. We found that the spectrum is nearly scale invariant under certain conditions. One interesting aspect of this model is that it is possible to derive the dynamical field equations for the tensor metric fluctuations, valid not just at cosmological scales, but also at astrophysical scales, from the same theoretical model. The astrophysical and cosmological scales are determined by the gravity-antigravity radius, which is a natural length scale of the model, that indicates when gravity becomes repulsive in nature.

Gravitational waves during inflation from a 5D large-scale repulsive gravity model

Science.gov (United States)

Reyes, Luz M.; Moreno, Claudia; Madriz Aguilar, José Edgar; Bellini, Mauricio

2012-10-01

We investigate, in the transverse traceless (TT) gauge, the generation of the relic background of gravitational waves, generated during the early inflationary stage, on the framework of a large-scale repulsive gravity model. We calculate the spectrum of the tensor metric fluctuations of an effective 4D Schwarzschild-de Sitter metric on cosmological scales. This metric is obtained after implementing a planar coordinate transformation on a 5D Ricci-flat metric solution, in the context of a non-compact Kaluza-Klein theory of gravity. We found that the spectrum is nearly scale invariant under certain conditions. One interesting aspect of this model is that it is possible to derive the dynamical field equations for the tensor metric fluctuations, valid not just at cosmological scales, but also at astrophysical scales, from the same theoretical model. The astrophysical and cosmological scales are determined by the gravity-antigravity radius, which is a natural length scale of the model, that indicates when gravity becomes repulsive in nature.

Gravitational waves during inflation from a 5D large-scale repulsive gravity model

Energy Technology Data Exchange (ETDEWEB)

Reyes, Luz M., E-mail: luzmarinareyes@gmail.com [Departamento de Matematicas, Centro Universitario de Ciencias Exactas e ingenierias (CUCEI), Universidad de Guadalajara (UdG), Av. Revolucion 1500, S.R. 44430, Guadalajara, Jalisco (Mexico); Moreno, Claudia, E-mail: claudia.moreno@cucei.udg.mx [Departamento de Matematicas, Centro Universitario de Ciencias Exactas e ingenierias (CUCEI), Universidad de Guadalajara (UdG), Av. Revolucion 1500, S.R. 44430, Guadalajara, Jalisco (Mexico); Madriz Aguilar, Jose Edgar, E-mail: edgar.madriz@red.cucei.udg.mx [Departamento de Matematicas, Centro Universitario de Ciencias Exactas e ingenierias (CUCEI), Universidad de Guadalajara (UdG), Av. Revolucion 1500, S.R. 44430, Guadalajara, Jalisco (Mexico); Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, C.P. 7600, Mar del Plata (Argentina); Instituto de Investigaciones Fisicas de Mar del Plata (IFIMAR) - Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) (Argentina)

2012-10-22

We investigate, in the transverse traceless (TT) gauge, the generation of the relic background of gravitational waves, generated during the early inflationary stage, on the framework of a large-scale repulsive gravity model. We calculate the spectrum of the tensor metric fluctuations of an effective 4D Schwarzschild-de Sitter metric on cosmological scales. This metric is obtained after implementing a planar coordinate transformation on a 5D Ricci-flat metric solution, in the context of a non-compact Kaluza-Klein theory of gravity. We found that the spectrum is nearly scale invariant under certain conditions. One interesting aspect of this model is that it is possible to derive the dynamical field equations for the tensor metric fluctuations, valid not just at cosmological scales, but also at astrophysical scales, from the same theoretical model. The astrophysical and cosmological scales are determined by the gravity-antigravity radius, which is a natural length scale of the model, that indicates when gravity becomes repulsive in nature.

Even-parity spin-triplet pairing by purely repulsive interactions for orbitally degenerate correlated fermions

International Nuclear Information System (INIS)

Zegrodnik, M; Bünemann, J; Spałek, J

2014-01-01

We demonstrate the stability of the spin-triplet paired s-wave (with an admixture of extended s-wave) state for the limit of purely repulsive interactions in a degenerate two-band Hubbard model of correlated fermions. The repulsive interactions limit represents an essential extension of our previous analysis (2013 New J. Phys. 15 073050), regarded here as I. We also show that near the half-filling the considered type of superconductivity can coexist with antiferromagnetism. The calculations have been carried out with the use of the so-called statistically consistent Gutzwiller approximation (SGA) for the case of a square lattice. We suggest that the electron correlations in conjunction with the Hund's rule exchange play the crucial role in stabilizing the real-space spin-triplet superconducting state. A sizable hybridization of the bands suppresses the homogeneous paired state. (paper)

Glass transition of repulsive charged rods (fd-viruses).

Science.gov (United States)

Kang, Kyongok

2014-05-14

It has recently been shown that suspensions of long and thin charged fibrous viruses (fd) form a glass at low ionic strengths. The corresponding thick electric double layers give rise to long-ranged repulsive electrostatic interactions, which lead to caging and structural arrest at concentrations far above the isotropic-nematic coexistence region. Structural arrest and freezing of the orientational texture are found to occur at the same concentration. In addition, various types of orientational textures are equilibrated below the glass transition concentration, ranging from a chiral-nematic texture with a large pitch (of about 100 μm), an X-pattern, and a tightly packed domain texture, consisting of helical domains with a relatively small pitch (of about 10 μm) and twisted boundaries. The dynamics of both particles as well as the texture are discussed, below and above the glass transition. Dynamic light scattering correlation functions exhibit two dynamical modes, where the slow mode is attributed to the elasticity of helical domains. On approach of the glass-transition concentration, the slow mode increases in amplitude, while as the amplitudes of the fast and slow mode become equal at the glass transition. Finally, interesting features of the "transient" behaviors of charged fd-rod glass are shown as the initial caging due to structural arrest, the propagation of flow originating from stress release, and the transition to the final metastable glass state. In addition to the intensity correlation function, power spectra are presented as a function of the waiting time, at the zero-frequency limit that may access to the thermal anomalities in a charged system.

Vortical null orbits, repulsive barriers, energy confinement in Kerr metric

Energy Technology Data Exchange (ETDEWEB)

Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; De Felice, F

1978-10-01

The complete analytical description of the null trajectories in the field of a Kerr naked singularity is given. Two peculiar phenomena are described: the existence of repulsive barriers in the r < O world and the existence of null circular bound orbits which surround the singularity in 'shells'. They distribute around the surface at r = m, which is the position of the horizon in the extreme black-hole case; this suggests that a naked singularity 'remembers' the position of the last horizon.

Evidence of central repulsion potential from pionic decay of s-shell Λ-hypernuclei

International Nuclear Information System (INIS)

Kumagai-Fuse, I.; Okabe, S.; Akaishi, Y.

1994-10-01

Pionic decays of A=4 and 5 hypernuclei are discussed to obtain information about a nucleus-Λ potential. Results for the available decay widths support as a whole that the nucleus-Λ potential has central repulsion not only in A=5 but also in A=4 hypernuclei. (author)

Effects of Coulomb repulsion on conductivity of heterojunction carbon nanotube quantum dots with spin-orbital coupling and interacting leads

Energy Technology Data Exchange (ETDEWEB)

Ogloblya, O.V., E-mail: olexandr.ogloblya@gmail.com [Taras Shevchenko National University, 64/13 Volodymyrska St., Kyiv 01601 (Ukraine); Kuznietsova, H.M. [Taras Shevchenko National University, 64/13 Volodymyrska St., Kyiv 01601 (Ukraine); Strzhemechny, Y.M. [Dept. of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States)

2017-01-01

We performed numerical studies for the conductance of a heterojunction carbon nanotube quantum dot (QD) with an extra spin orbital quantum number and a conventional QD in which the electron state is determined only by the spin quantum number. Our computational approach took into account the spin-orbit interaction and the Coulomb repulsion both between electrons on a QD as well as between the QD electron and the contacts. We utilized an approach based on the Keldysh non-equilibrium Green's function formalism as well as the equation of motion technique. We focused on the case of a finite Coulombic on-site repulsion and considered two possible cases of applied voltage: spin bias and conventional bias. For the system of interest we obtained bias spectroscopy diagrams, i.e. contour charts showing dependence of conductivity on two variables - voltage and the energy level position in a QD - which can be controlled by the plunger gate voltage. The finite Coulombic repulsion splits the density of states into two distinct maxima with the energy separation between them controlled by that parameter. It was also shown that an increase of either the value of the on-site Coulomb repulsion in a QD or the parameter of the Coulomb repulsion between the electrons in the QD and the contacts leads to an overall shift of the density of electronic states dependence toward higher energy values. Presence of the QD-lead interaction yields formation of a new pair of peaks in the differential conductance dependence. We also show that existence of four quantum states in a QD leads to abrupt changes in the density of states. These results could be beneficial for potential applications in nanotube-based amperometric sensors.

Pairing from strong repulsion in triangular lattice Hubbard model

Science.gov (United States)

Zhang, Shang-Shun; Zhu, Wei; Batista, Cristian D.

2018-04-01

We propose a pairing mechanism between holes in the dilute limit of doped frustrated Mott insulators. Hole pairing arises from a hole-hole-magnon three-body bound state. This pairing mechanism has its roots on single-hole kinetic energy frustration, which favors antiferromagnetic (AFM) correlations around the hole. We demonstrate that the AFM polaron (hole-magnon bound state) produced by a single hole propagating on a field-induced polarized background is strong enough to bind a second hole. The effective interaction between these three-body bound states is repulsive, implying that this pairing mechanism is relevant for superconductivity.

Repulsively interacting fermions in a two-dimensional deformed trap with spin-orbit coupling

DEFF Research Database (Denmark)

Marchukov, O. V.; Fedorov, D. V.; Jensen, A. S.

2015-01-01

We investigate a two-dimensional system of fermions with two internal (spin) degrees of freedom. It is confined by a deformed harmonic trap and subject to a Zeeman field, Rashba or Dresselhaus one-body spin-orbit couplings and two-body short range repulsion. We obtain self-consistent mean-field $N...

New models for intermolecular repulsion and their application to Van Der Waals complexes and crystals of organic molecules

International Nuclear Information System (INIS)

Tsui, H.H.Y.

2001-01-01

Model intermolecular potentials are required for simulations of molecules in the gas, liquid, or solid phase. The widely used isotropic atom-atom model potentials are empirically fitted and based on the assumptions of transferability, combining rules and that atoms in molecules are spherical. This thesis develops a non-empirical method of modelling repulsion by applying the overlap model, which we show as a general non-empirical method of deriving repulsion potentials for a specific molecule. In this thesis, the repulsion parameters for an exponential atom-atom model potential are obtained from the ab initio charge density of a small organic molecule by making the assumption that the repulsion is proportional to the overlap of a pair of molecules. The proportionality constant is fixed by a limited number of intermolecular perturbation theory (IMPT) calculations. To complete the model potential, the electrostatic interaction is represented by a distributed multipole analysis, and the Slater-Kirkwood formula is used for the dispersion. These non-empirical potentials can reproduce experimental crystal structure when applied to crystal structure prediction of an oxyboryl derivative. A detailed study on further improving the overlap model was carried out for phenol-water, by including other minor intermolecular contributions of charge-transfer and penetration. High quality ab initio calculations on the complex were performed for use in comparison. To compare with experimental data, diffusion Monte Carlo simulations were performed with the potential, so that the effects of anharmonic zero-point motion on structure and energy of the system are included. When the system is too large for an IMPT calculation, the proportionality constant can be determined empirically by fitting the cell volume as shown in our study of crystal structures of chlorothalonil. This is used with an anisotropic repulsion model that has been derived for Cl and N atoms in chlorothalonil. This model

The effective communication methodology and influence of merit information on nuclear power

International Nuclear Information System (INIS)

Oiso, Shinichi

2007-01-01

It was found by the survey the author carried out in 2005 that there is a possibility that even the person who opposes nuclear power generation may change his or her opinion after understanding the advantage of nuclear power. Then, how should merit information be transmitted? Is there a possibility that people feel repulsion after receiving merit information? What is the influence of providing merit information of nuclear power? Those kinds of questions were investigated in 2006. As a result, it was found that the use of magazine and NPO/NGO is effective. The utilization of all-night television broadcasting, iPod, energy environmental education in schools and science cafe have an effect too, especially for young generation. It was also found that 20% or less of the people feel repulsion for providing merit information of nuclear power. Concerning people's attitude towards nuclear power utilization, it was found that the number of those who support nuclear power generation tended to increase significantly by providing information depicting merits or benefits of nuclear power, however, it did not increase by explaining electric power companies' effort to promote nuclear power. Further more, concerning to the image of a nuclear power station site, it became clear that merit information of nuclear power provided positive effect for some items in explaining nuclear power generation. (author)

Quantum Statistics: Is there an effective fermion repulsion or boson attraction?

OpenAIRE

Mullin, W. J.; Blaylock, G.

2003-01-01

Physicists often claim that there is an effective repulsion between fermions, implied by the Pauli principle, and a corresponding effective attraction between bosons. We examine the origins of such exchange force ideas, the validity for them, and the areas where they are highly misleading. We propose that future explanations of quantum statistics should avoid the idea of a effective force completely and replace it with more appropriate physical insights, some of which are suggested here.

Bridge density functional approximation for non-uniform hard core repulsive Yukawa fluid

International Nuclear Information System (INIS)

Zhou Shiqi

2008-01-01

In this work, a bridge density functional approximation (BDFA) (J. Chem. Phys. 112, 8079 (2000)) for a non-uniform hard-sphere fluid is extended to a non-uniform hard-core repulsive Yukawa (HCRY) fluid. It is found that the choice of a bulk bridge functional approximation is crucial for both a uniform HCRY fluid and a non-uniform HCRY fluid. A new bridge functional approximation is proposed, which can accurately predict the radial distribution function of the bulk HCRY fluid. With the new bridge functional approximation and its associated bulk second order direct correlation function as input, the BDFA can be used to well calculate the density profile of the HCRY fluid subjected to the influence of varying external fields, and the theoretical predictions are in good agreement with the corresponding simulation data. The calculated results indicate that the present BDFA captures quantitatively the phenomena such as the coexistence of solid-like high density phase and low density gas phase, and the adsorption properties of the HCRY fluid, which qualitatively differ from those of the fluids combining both hard-core repulsion and an attractive tail. (condensed matter: structure, thermal and mechanical properties)

Repulsive polarons and itinerant ferromagnetism in strongly polarized Fermi gases

DEFF Research Database (Denmark)

Massignan, Pietro; Bruun, Georg

2011-01-01

We analyze the properties of a single impurity immersed in a Fermi sea. At positive energy and scattering lengths, we show that the system possesses a well-defined but metastable excitation, the repulsive polaron, and we calculate its energy, quasiparticle residue and effective mass. From...... polarized (ferromagnetic) domains are then examined for a binary mixture of atoms with a general mass ratio. Our results indicate that mass imbalance lowers the critical interaction strength for phase-separation, but that very short quasiparticle decay times will complicate the experimental observation...

Crossing Over from Attractive to Repulsive Interactions in a Tunneling Bosonic Josephson Junction.

Science.gov (United States)

Spagnolli, G; Semeghini, G; Masi, L; Ferioli, G; Trenkwalder, A; Coop, S; Landini, M; Pezzè, L; Modugno, G; Inguscio, M; Smerzi, A; Fattori, M

2017-06-09

We explore the interplay between tunneling and interatomic interactions in the dynamics of a bosonic Josephson junction. We tune the scattering length of an atomic ^{39}K Bose-Einstein condensate confined in a double-well trap to investigate regimes inaccessible to other superconducting or superfluid systems. In the limit of small-amplitude oscillations, we study the transition from Rabi to plasma oscillations by crossing over from attractive to repulsive interatomic interactions. We observe a critical slowing down in the oscillation frequency by increasing the strength of an attractive interaction up to the point of a quantum phase transition. With sufficiently large initial oscillation amplitude and repulsive interactions, the system enters the macroscopic quantum self-trapping regime, where we observe coherent undamped oscillations with a self-sustained average imbalance of the relative well population. The exquisite agreement between theory and experiments enables the observation of a broad range of many body coherent dynamical regimes driven by tunable tunneling energy, interactions and external forces, with applications spanning from atomtronics to quantum metrology.

Attractive versus repulsive interactions in the Bose-Einstein condensation dynamics of relativistic field theories

Science.gov (United States)

Berges, J.; Boguslavski, K.; Chatrchyan, A.; Jaeckel, J.

2017-10-01

We study the impact of attractive self-interactions on the nonequilibrium dynamics of relativistic quantum fields with large occupancies at low momenta. Our primary focus is on Bose-Einstein condensation and nonthermal fixed points in such systems. For a model system, we consider O (N ) -symmetric scalar field theories. We use classical-statistical real-time simulations as well as a systematic 1 /N expansion of the quantum (two-particle-irreducible) effective action to next-to-leading order. When the mean self-interactions are repulsive, condensation occurs as a consequence of a universal inverse particle cascade to the zero-momentum mode with self-similar scaling behavior. For attractive mean self-interactions, the inverse cascade is absent, and the particle annihilation rate is enhanced compared to the repulsive case, which counteracts the formation of coherent field configurations. For N ≥2 , the presence of a nonvanishing conserved charge can suppress number-changing processes and lead to the formation of stable localized charge clumps, i.e., Q balls.

Coulomb Repulsion Effect in Two-electron Non-adiabatic Tunneling through a One-level redox Molecule

DEFF Research Database (Denmark)

Medvedev, Igor M.; Kuznetsov, Alexander M.; Ulstrup, Jens

2009-01-01

We investigated Coulomb repulsion effects in nonadiabatic (diabatic) two-electron tunneling through a redox molecule with a single electronic level in a symmetric electrochemical contact under ambient conditions, i.e., room temperature and condensed matter environment. The electrochemical contact...

Development and analysis of a twelfth degree and order gravity model for Mars

Science.gov (United States)

Christensen, E. J.; Balmino, G.

1979-01-01

Satellite geodesy techniques previously applied to artificial earth satellites have been extended to obtain a high-resolution gravity field for Mars. Two-way Doppler data collected by 10 Deep Space Network (DSN) stations during Mariner 9 and Viking 1 and 2 missions have been processed to obtain a twelfth degree and order spherical harmonic model for the martian gravitational potential. The quality of this model was evaluated by examining the rms residuals within the fit and the ability of the model to predict the spacecraft state beyond the fit. Both indicators show that more data and higher degree and order harmonics will be required to further refine our knowledge of the martian gravity field. The model presented shows much promise, since it resolves local gravity features which correlate highly with the martian topography. An isostatic analysis based on this model, as well as an error analysis, shows rather complete compensation on a global (long wavelength) scale. Though further model refinements are necessary to be certain, local (short wavelength) features such as the shield volcanos in Tharsis appear to be uncompensated. These are interpreted to place some bounds on the internal structure of Mars.

Two-component fluid membranes near repulsive walls: Linearized hydrodynamics of equilibrium and nonequilibrium states.

Science.gov (United States)

Sankararaman, Sumithra; Menon, Gautam I; Sunil Kumar, P B

2002-09-01

We study the linearized hydrodynamics of a two-component fluid membrane near a repulsive wall, using a model that incorporates curvature-concentration coupling as well as hydrodynamic interactions. This model is a simplified version of a recently proposed one [J.-B. Manneville et al., Phys. Rev. E 64, 021908 (2001)] for nonequilibrium force centers embedded in fluid membranes, such as light-activated bacteriorhodopsin pumps incorporated in phospholipid egg phosphatidyl choline (EPC) bilayers. The pump-membrane system is modeled as an impermeable, two-component bilayer fluid membrane in the presence of an ambient solvent, in which one component, representing active pumps, is described in terms of force dipoles displaced with respect to the bilayer midpoint. We first discuss the case in which such pumps are rendered inactive, computing the mode structure in the bulk as well as the modification of hydrodynamic properties by the presence of a nearby wall. These results should apply, more generally, to equilibrium fluid membranes comprised of two components, in which the effects of curvature-concentration coupling are significant, above the threshold for phase separation. We then discuss the fluctuations and mode structure in the steady state of active two-component membranes near a repulsive wall. We find that proximity to the wall smoothens membrane height fluctuations in the stable regime, resulting in a logarithmic scaling of the roughness even for initially tensionless membranes. This explicitly nonequilibrium result is a consequence of the incorporation of curvature-concentration coupling in our hydrodynamic treatment. This result also indicates that earlier scaling arguments which obtained an increase in the roughness of active membranes near repulsive walls upon neglecting the role played by such couplings may need to be reevaluated.

Twelfth European TRIGA users conference. Papers and abstracts

International Nuclear Information System (INIS)

2008-01-01

The Twelfth European TRIGA Users Conference was held in Pitesti, Romania, on September 28 - October 1, 1992, under the sponsorship of the Institute for Nuclear Research. The papers which follow in this document are presented in the same order as listed in the Conference Program. All papers which were received for publication (44) have been included. Those papers which were presented but not received for publication are presented in abstract form (3). The European TRIGA9 Owners' Group was fortunate to be hosted by the owners and users of the world's largest TRIGA reactor - the 14-MW Romanian research and test reactor. For too many years it has been impossible to enjoy open interactions with the Romanian researchers. By hosting the 1992 European TRIGA Users' Conference in Romania, the Romanians accomplished a breakthrough in the exchange of TRIGA reactor technology. It was very interesting for the Conference attendees from the West to learn about the large scope of excellent work conducted in Romania, especially at the Institute of Nuclear Research in Pitesti. Similarly, it was fortunate that a large attendance of Romanian researchers from many institutes, universities, and government agencies could attend the Conference and interact with their counterparts from outside Romania. The proceedings of the conference were structured onto the following 6 subject matters: - Opening Session and Introduction; - Session I, Operating and Maintenance Experience (10 papers); - Session II, Reactor Physics And Fuel Utilization (11 papers); - Session III, Instrumentation and Control (5 papers); - Session IV, Irradiation Facilities, Experimental Accessories (8 papers); - Session V, Applications, New Development of TRIGA Concept (6 papers). The document is completed with the abstracts of 3 contributions. A number of 19 experts from Austria, Germany, Italy, United States, Turkey, Morocco, England, Slovenia and Albania, that use TRIGA reactors, and Romania attended the conference. The

A brief introduction of the constructing work of national radiation monitoring system during the twelfth five-year

International Nuclear Information System (INIS)

Liu Hua; Zhao Yongkang; Pan Su; Zhang Jiali; Yang Bin

2013-01-01

Radiation monitoring is the technical groundwork of nuclear and radiation safety regulating. In order to overcome the challenges coming with the development of nuclear energy and technology in china, the program of constructing National Radiation Monitoring System (NRMS) was put forward in the twelfth five-year plan of nuclear safety and prevention of radiation pollution, and the view target in 2020. The implementation plan of the constructing of NRMS has been drew up by the Ministry of Environmental Protection in 2012, which including the construction of organization and human resource system, laws and standards system, quality assurance system, technical research and innovation system, and capability insurance system. A brief introduction of the implementation plan was given in the article, the achievements during the eleventh five-year were reviewed, the challenges and working points were analyzed. (authors)

Repulsive Gravity in the Oppenheimer-Snyder Collapsar

Directory of Open Access Journals (Sweden)

Marshall T. W.

2016-07-01

Full Text Available The Oppenheimer-Snyder metric for a collapsing dust ball has a well defined equilib- rium state when the time coordinate goes to plus infinity. The entire ball is contained within the gravitational radius r 0 , but half of its content lies within a thin shell between r 0 and 0 : 94 r 0 . This state has the acausal property that no light ray escapes from it, but if one boundary condition at the surface, which Oppenheimer and Snyder imposed without justification, is removed, then all points in the interior remain in causal contact by null geodesics with the exterior. This modification causes the half shell’s interior radius to increase to 0 : 97 r 0 . Together with the results of a previous article on the den- sity inside a spherosymmetric neutron star, the present results indicate that, in contrast with the universal attraction of Newtonian gravity, General Relativity gives gravitational repulsion at high density.

Phases and amplitudes for a modified repulsive Coulomb field

International Nuclear Information System (INIS)

Chidichimo, M.C.; Davison, T.S.

1990-01-01

The asymptotic form of the radial wave function for positive-energy states is calculated for the case of a repulsive Coulomb field. The cases of a pure Coulomb potential and a modified Coulomb potential are considered. Second-order analytic solutions for the amplitudes and phases are obtained when the modifications to the pure Coulombic potential take the form αr -2 +βr -3 +γr -4 , using the Jeffreys or WKB method. For the case of a pure Coulomb field, numerical results obtained from this method were compared with ''exact'' numerical results that were obtained using the analytic properties of the Coulomb wave functions. Tables are presented to show the conditions under which the method is accurate

Study on a kind of ϕ-Laplacian Liénard equation with attractive and repulsive singularities.

Science.gov (United States)

Xin, Yun; Cheng, Zhibo

2017-01-01

In this paper, by application of the Manasevich-Mawhin continuation theorem, we investigate the existence of a positive periodic solution for a kind of ϕ -Laplacian singular Liénard equation with attractive and repulsive singularities.

Enhancement of spin polarization induced by Coulomb on-site repulsion between localized pz electrons in graphene embedded with line defects.

Science.gov (United States)

Ren, Ji-Chang; Wang, Zhigang; Zhang, Rui-Qin; Ding, Zejun; Van Hove, Michel A

2015-11-11

It is well known that the effect of Coulomb on-site repulsion can significantly alter the physical properties of the systems that contain localized d and/or f electrons. However, little attention has been paid to the Coulomb on-site repulsion between localized p electrons. In this study, we demonstrated that Coulomb on-site repulsion between localized pz electrons also plays an important role in graphene embedded with line defects. It is shown that the magnetism of the system largely depends on the choice of the effective Coulomb on-site parameter Ueff. Ueff at the edges of the defect enhances the exchange splitting, which increases the magnetic moment and stabilizes a ferromagnetic state of the system. In contrast, Ueff at the center of the defect weakens the spin polarization of the system. The behavior of the magnetism is explained with the Stoner criterion and the charge accumulation at the edges of the defect. Based on the linear response approach, we estimate reasonable values of Ueff to be 2.55 eV (2.3 eV) at the center (edges) of the defects. More importantly, using a DFT+U+J method, we find that exchange interactions between localized p electrons also play an important role in the spin polarization of the system. These results imply that Coulomb on-site repulsion is necessary to describe the strong interaction between localized pz electrons of carbon related materials.

Repulsion between oppositely charged rod-shaped macromolecules: Role of overcharging and ionic confinement

Science.gov (United States)

Antila, Hanne S.; Van Tassel, Paul R.; Sammalkorpi, Maria

2017-09-01

The interaction between two oppositely charged rod-shaped macro-ions in a micro-ion solution is investigated via Monte Carlo simulations of the primitive model. The focus is on the asymmetry in rod and/or ion charge, i.e., conditions where oppositely charged objects can repel one another. For equally and oppositely charged rods with asymmetric z:1 micro-ions, repulsion may be induced by overcharging one of the rods with the z valent ions. For asymmetrically charged rods in a symmetric z:z micro-ion solution, a repulsive interaction—at separation of the order of one ion diameter—can arise via an unbalanced osmotic pressure contribution from the ionic atmosphere in the inter-rod space, and an attractive interaction—at a smaller separation—may occur due to a "squeezing out" of the micro-ions from the space between the rods (with a consequent gain in entropy). The thermodynamics of each mechanism is investigated in terms of rod charge and size and micro-ion valence, size, and concentration. Our findings contribute to the understanding of the complex role of charge asymmetry on the interaction of, for example, oppositely charged polyelectrolytes, functionalized nanotubes, and rod-like biomolecules, e.g., viruses.

Effect of the repulsive force in the HTSC-permanent magnet hybrid bearing system

International Nuclear Information System (INIS)

Ohashi, S.; Kobayashi, S.

2009-01-01

Magnetic levitation using the pinning force of the YBaCuO high-T c bulk superconductor (HTSC) materials has an advantage to achieve stable levitation without control. To increase levitation force, the HTSC-permanent magnet hybrid magnetic bearing system is introduced. A circular shaped three phase Nd-Fe-B permanent magnet is installed on the rotor, and HTSC bulk superconductor is set on the stator. The additional permanent magnet is installed under the HTSC. Repulsive force of the permanent magnet is used for levitation, and pinning force between the HTSC and permanent magnet is used for guidance force of the bearing. In this system, relationship between permanent magnet and the HTSC is important. When repulsive force of the permanent magnet is large, pinning force of superconductor is used to keep the rotor position. As a result, stability for the lateral direction is decreased with hybrid system. For levitation force, effect of the hybrid system is not observed with column HTSC. Compared with the ring HTSC results, the following thing is considered. Because there is no space that flux of one permanent magnet acts on the other one with the column HTSC configuration, interaction between two permanent magnets becomes small.

Synergy of cell-cell repulsion and vacuolation in a computational model of lumen formation.

Science.gov (United States)

Boas, Sonja E M; Merks, Roeland M H

2014-03-06

A key step in blood vessel development (angiogenesis) is lumen formation: the hollowing of vessels for blood perfusion. Two alternative lumen formation mechanisms are suggested to function in different types of blood vessels. The vacuolation mechanism is suggested for lumen formation in small vessels by coalescence of intracellular vacuoles, a view that was extended to extracellular lumen formation by exocytosis of vacuoles. The cell-cell repulsion mechanism is suggested to initiate extracellular lumen formation in large vessels by active repulsion of adjacent cells, and active cell shape changes extend the lumen. We used an agent-based computer model, based on the cellular Potts model, to compare and study both mechanisms separately and combined. An extensive sensitivity analysis shows that each of the mechanisms on its own can produce lumens in a narrow region of parameter space. However, combining both mechanisms makes lumen formation much more robust to the values of the parameters, suggesting that the mechanisms may work synergistically and operate in parallel, rather than in different vessel types.

Synergy of cell–cell repulsion and vacuolation in a computational model of lumen formation

Science.gov (United States)

Boas, Sonja E. M.; Merks, Roeland M. H.

2014-01-01

A key step in blood vessel development (angiogenesis) is lumen formation: the hollowing of vessels for blood perfusion. Two alternative lumen formation mechanisms are suggested to function in different types of blood vessels. The vacuolation mechanism is suggested for lumen formation in small vessels by coalescence of intracellular vacuoles, a view that was extended to extracellular lumen formation by exocytosis of vacuoles. The cell–cell repulsion mechanism is suggested to initiate extracellular lumen formation in large vessels by active repulsion of adjacent cells, and active cell shape changes extend the lumen. We used an agent-based computer model, based on the cellular Potts model, to compare and study both mechanisms separately and combined. An extensive sensitivity analysis shows that each of the mechanisms on its own can produce lumens in a narrow region of parameter space. However, combining both mechanisms makes lumen formation much more robust to the values of the parameters, suggesting that the mechanisms may work synergistically and operate in parallel, rather than in different vessel types. PMID:24430123

Observation of attractive and repulsive polarons in a Bose-Einstein condensate

DEFF Research Database (Denmark)

Jørgensen, Nils Byg

2016-01-01

(BEC) has not yet been realized. Here, we use radio frequency spectroscopy of ultracold bosonic 39K atoms to experimentally demonstrate the existence of a well-defined quasiparticle state of an impurity interacting with a BEC. We measure the energy of the impurity both for attractive and repulsive...... interactions, and find excellent agreement with theories that incorporate three-body correlations. The spectral response consists of a well-defined quasiparticle peak at weak coupling, while for increasing interaction strength, the spectrum is strongly broadened and becomes dominated by the many-body continuum...

Ensemble averaged coherent state path integral for disordered bosons with a repulsive interaction (Derivation of mean field equations)

International Nuclear Information System (INIS)

Mieck, B.

2007-01-01

We consider bosonic atoms with a repulsive contact interaction in a trap potential for a Bose-Einstein condensation (BEC) and additionally include a random potential. The ensemble averages for two models of static (I) and dynamic (II) disorder are performed and investigated in parallel. The bosonic many body systems of the two disorder models are represented by coherent state path integrals on the Keldysh time contour which allow exact ensemble averages for zero and finite temperatures. These ensemble averages of coherent state path integrals therefore present alternatives to replica field theories or super-symmetric averaging techniques. Hubbard-Stratonovich transformations (HST) lead to two corresponding self-energies for the hermitian repulsive interaction and for the non-hermitian disorder-interaction. The self-energy of the repulsive interaction is absorbed by a shift into the disorder-self-energy which comprises as an element of a larger symplectic Lie algebra sp(4M) the self-energy of the repulsive interaction as a subalgebra (which is equivalent to the direct product of M x sp(2); 'M' is the number of discrete time intervals of the disorder-self-energy in the generating function). After removal of the remaining Gaussian integral for the self-energy of the repulsive interaction, the first order variations of the coherent state path integrals result in the exact mean field or saddle point equations, solely depending on the disorder-self-energy matrix. These equations can be solved by continued fractions and are reminiscent to the 'Nambu-Gorkov' Green function formalism in superconductivity because anomalous terms or pair condensates of the bosonic atoms are also included into the selfenergies. The derived mean field equations of the models with static (I) and dynamic (II) disorder are particularly applicable for BEC in d=3 spatial dimensions because of the singularity of the density of states at vanishing wavevector. However, one usually starts out from

Twelfth annual meeting of the International Working Group on Fast Reactors. Summary report. Part I

Energy Technology Data Exchange (ETDEWEB)

NONE

1979-05-01

The Twelfth Annual Meeting of the IWGFR was held in accordance with the recommendation of the previous AGM,in Vienna from 27 to 30 March 1979. The meeting was attended by the Member States of the group: France, the Federal Republic of Germany, Italy, Japan, the United Kingdom, and the USA, as well as by representatives from CEC, IAEA and OECD and observer from the USSR. This document includes: review of the IWGFR Activities for the period since the Eleventh Annual Meeting of the Group; preliminary programme of international conference on breeder reactors as a world energy resource and the breeder fuel cycle; list of meetings on atomic energy which may be of interest to the IWGFR Members; IWGFR criteria for supporting some of the international conferences; list of proposed topics for the IWGFR Specialists' Meetings; list of topics for review articles on LMFBR recommended for publication by the IAEA; list of meetings sponsored by the IWGFR; a list of members of the International Working Group on Fast Reactors.

Twelfth annual meeting of the International Working Group on Fast Reactors. Summary report. Part I

International Nuclear Information System (INIS)

1979-05-01

The Twelfth Annual Meeting of the IWGFR was held in accordance with the recommendation of the previous AGM,in Vienna from 27 to 30 March 1979. The meeting was attended by the Member States of the group: France, the Federal Republic of Germany, Italy, Japan, the United Kingdom, and the USA, as well as by representatives from CEC, IAEA and OECD and observer from the USSR. This document includes: review of the IWGFR Activities for the period since the Eleventh Annual Meeting of the Group; preliminary programme of international conference on breeder reactors as a world energy resource and the breeder fuel cycle; list of meetings on atomic energy which may be of interest to the IWGFR Members; IWGFR criteria for supporting some of the international conferences; list of proposed topics for the IWGFR Specialists' Meetings; list of topics for review articles on LMFBR recommended for publication by the IAEA; list of meetings sponsored by the IWGFR; a list of members of the International Working Group on Fast Reactors

Partial synchronization of relaxation oscillators with repulsive coupling in autocatalytic integrate-and-fire model and electrochemical experiments

Science.gov (United States)

Kori, Hiroshi; Kiss, István Z.; Jain, Swati; Hudson, John L.

2018-04-01

Experiments and supporting theoretical analysis are presented to describe the synchronization patterns that can be observed with a population of globally coupled electrochemical oscillators close to a homoclinic, saddle-loop bifurcation, where the coupling is repulsive in the electrode potential. While attractive coupling generates phase clusters and desynchronized states, repulsive coupling results in synchronized oscillations. The experiments are interpreted with a phenomenological model that captures the waveform of the oscillations (exponential increase) followed by a refractory period. The globally coupled autocatalytic integrate-and-fire model predicts the development of partially synchronized states that occur through attracting heteroclinic cycles between out-of-phase two-cluster states. Similar behavior can be expected in many other systems where the oscillations occur close to a saddle-loop bifurcation, e.g., with Morris-Lecar neurons.

Beth-Uhlenbeck approach for repulsive interactions between baryons in a hadron gas

Science.gov (United States)

Vovchenko, Volodymyr; Motornenko, Anton; Gorenstein, Mark I.; Stoecker, Horst

2018-03-01

The quantum mechanical Beth-Uhlenbeck (BU) approach for repulsive hard-core interactions between baryons is applied to the thermodynamics of a hadron gas. The second virial coefficient a2—the "excluded volume" parameter—calculated within the BU approach is found to be temperature dependent, and it differs dramatically from the classical excluded volume (EV) model result. At temperatures T =100 -200 MeV, the widely used classical EV model underestimates the EV parameter for nucleons at a given value of the nucleon hard-core radius by large factors of 3-4. Previous studies, which employed the hard-core radii of hadrons as an input into the classical EV model, have to be re-evaluated using the appropriately rescaled EV parameters. The BU approach is used to model the repulsive baryonic interactions in the hadron resonance gas (HRG) model. Lattice data for the second- and fourth-order net baryon susceptibilities are described fairly well when the temperature dependent BU baryonic excluded volume parameter corresponds to nucleon hard-core radii of rc=0.25 -0.3 fm. Role of the attractive baryonic interactions is also considered. It is argued that HRG model with a constant baryon-baryon EV parameter vN N≃1 fm3 provides a simple yet efficient description of baryon-baryon interaction in the crossover temperature region.

Effect of particle-particle attractive and repulsive interactions on the retention in field-flow fractionation

Czech Academy of Sciences Publication Activity Database

Janča, J.; Berneron, J.-F.; Stejskal, Jaroslav

2010-01-01

Roč. 15, č. 8 (2010), s. 536-543 ISSN 1023-666X R&D Projects: GA AV ČR IAA400500905 Institutional research plan: CEZ:AV0Z40500505 Keywords : attractive and repulsive interactions * colloidal crystals * colloidal particles Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.814, year: 2010

Review - On-chip diamagnetic repulsion in continuous flow

Directory of Open Access Journals (Sweden)

Mark D Tarn, Noriyuki Hirota, Alexander Iles and Nicole Pamme

2009-01-01

Full Text Available We explore the potential of a microfluidic continuous flow particle separation system based on the repulsion of diamagnetic materials from a high magnetic field. Diamagnetic polystyrene particles in paramagnetic manganese (II chloride solution were pumped into a microfluidic chamber and their deflection behaviour in a high magnetic field applied by a superconducting magnet was investigated. Two particle sizes (5 and 10 μm were examined in two concentrations of MnCl2 (6 and 10%. The larger particles were repelled to a greater extent than the smaller ones, and the effect was greatly enhanced when the particles were suspended in a higher concentration of MnCl2. These findings indicate that the system could be viable for the separation of materials of differing size and/or diamagnetic susceptibility, and as such could be suitable for the separation and sorting of small biological species for subsequent studies.

Study of a model Fermi liquid interacting via a hard-core repulsive potential and an attractive tail

International Nuclear Information System (INIS)

Ng, Tai Kai; Singwi, K.S.

1986-02-01

In this paper we present an extensive microscopic study of the collective and single-particle properties of a model Fermi liquid whose particles interact via a repulsive hard-core potential and an attractive tail. The model system is intended to simulate liquid 3 He. The study is based on an approximate scheme of Singwi, Tosi, Land and Sjoelander (STLS) which was devised to treat correlations in Coulomb Fermi liquids. The primary aim of this study is to learn whether the model system is capable of reproducing some of the salient features observed in normal liquid 3 He, and about the role of the repulsive and attractive parts of the potential. We have calculated the Landau parameters F 0 /sup s/ and F 0 /sup a/ and their variation with pressure, the wave number and pressure dependence of the spin-symmetric and spin-anti-symmetric polarization potentials, pressure dependence of the dispersion of the zero sound, the static structure factors and the quasiparticle mass. Although we make no quantitative claims when comparing our calculations with experiments in real liquid 3 He, we do conclude that our model system within the framework of the STLS scheme can account qualitatively for the latter. Besides, since the theory is microscopic in nature and is parameter free, it has enabled us to understand better the role of the repulsive and the attractive parts of the bare potential in determining the properties of liquid 3 He. 27 figs., 2 tabs

Attractive and Repulsive Forces on Particles in Oscillatory Flow

Science.gov (United States)

Agarwal, Siddhansh; Rallabandi, Bhargav; Raju, David; Thameem, Raqeeb; Hilgenfeldt, Sascha

2016-11-01

A large class of oscillating flows gives rise to rectified streaming motion of the fluid. It has recently been shown that particle transport in such flows, excited by bubbles oscillating at ultrasound frequencies, leads to differential displacement and efficient sorting of microparticles by size. We derive a general expression for the instantaneous radial force experienced by a small spherical particle in the vicinity of an oscillating interface, and generalize the radial projection of the Maxey-Riley equation to include this effect. Varying relevant system parameters, we show that the net effect on the particle can be either an attraction to or a repulsion from the bubble surface, depending in particular on the particle size and the particle/fluid density contrast. We demonstrate that these predictions are in agreement with a variety of experiments.

The decay of a false vacuum and the density of states in a random, repulsive potential

International Nuclear Information System (INIS)

Neuberger, H.

1982-01-01

The replica method is applied to a disordered system built out of randomly distributed, purely repulsive scattering centers. The emerging field theoretical model has a classical solution, a bounce, which gives both the leading form of the level density and the typical ground-state wave function. (orig.)

How Confinement-Induced Structures Alter the Contribution of Hydrodynamic and Short-Ranged Repulsion Forces to the Viscosity of Colloidal Suspensions

Directory of Open Access Journals (Sweden)

Meera Ramaswamy

2017-10-01

Full Text Available Confined systems ranging from the atomic to the granular are ubiquitous in nature. Experiments and simulations of such atomic and granular systems have shown a complex relationship between the microstructural arrangements under confinement, the short-ranged particle stresses, and flow fields. Understanding the same correlation between structure and rheology in the colloidal regime is important due to the significance of such suspensions in industrial applications. Moreover, colloidal suspensions exhibit a wide range of structures under confinement that could considerably modify such force balances and the resulting viscosity. Here, we use a combination of experiments and simulations to elucidate how confinement-induced structures alter the relative contributions of hydrodynamic and short-range repulsive forces to produce up to a tenfold change in the viscosity. In the experiments we use a custom-built confocal rheoscope to image the particle configurations of a colloidal suspension while simultaneously measuring its stress response. We find that as the gap decreases below 15 particle diameters, the viscosity first decreases from its bulk value, shows fluctuations with the gap, and then sharply increases for gaps below 3 particle diameters. These trends in the viscosity are shown to strongly correlate with the suspension microstructure. Further, we compare our experimental results to those from two different simulations techniques, which enables us to determine the relative contributions of hydrodynamic and short-range repulsive stresses to the suspension rheology. The first method uses the lubrication approximation to find the hydrodynamic stress and includes a short-range repulsive force between the particles while the second is a Stokesian dynamics simulation that calculates the full hydrodynamic stress in the suspension. We find that the decrease in the viscosity at moderate confinements has a significant contribution from both the

Hebrew and Latin astrology in the twelfth century: the example of the location of pain.

Science.gov (United States)

Burnett, Charles

2010-06-01

The formative period of Latin and Hebrew astrology occurred virtually simultaneously in both cultures. In the second quarter of the twelfth century the terminology of the subject was established and the textbooks which became authoritative were written. The responsibility for this lay almost entirely with two scholars: John of Seville for the Latins, and Abraham ibn Ezra for the Jews. It is unlikely to have been by coincidence that the same developments in astrology occurred in these two cultures. John of Seville and Abraham ibn Ezra were both brought up within the Islamic culture of Spain, and their astrology was Arabic astrology. Moreover, some scholars have thought that John's origins were Jewish, while Ibn Ezra is known to have collaborated with Latin scholars (whose names are not recorded). It cannot be a coincidence that they forged the science of astrology for their respect co-religionists at almost the same time. Yet, very little research has been done on the possible relations between the two scholars. The purpose of this paper is to begin to explore this relationship, and to illustrate it in particular by their shared doctrine concern the location of pain.

Control of charged droplets using electrohydrodynamic repulsion for circular droplet patterning

International Nuclear Information System (INIS)

Kim, Bumjoo; Sung, Jungwoo; Lim, Geunbae; Nam, Hyoryung; Kim, Sung Jae; Joo, Sang W

2011-01-01

We report a novel method to form a circular pattern of monodisperse microdroplets using an electrohydrodynamic repulsion (EDR) mechanism. EDR is a phenomenon of electrostatical bounced microdroplets from an accumulated droplet on a bottom substrate. In addition to a regular EDR system, by placing a ring electrode between the capillary and ground substrate, two separate regions were created. A parameter study of two regions was carried out for droplet formation and falling velocity to control the radius of the generated droplets and the circular patterns independently. Based on energy conservation theory, our experimental results showed that the free-falling region exerted crucial influences on the sizes of the circular patterns

Nucleus-nucleus potential with repulsive core and elastic scattering. Part 1. Nucleus-nucleus interaction potential

International Nuclear Information System (INIS)

Davidovs'ka, O.Yi.; Denisov, V.Yu.; Nesterov, V.O.

2010-01-01

Various approaches for nucleus-nucleus interaction potential evaluation are discussed in details. It is shown that the antisymmetrization of nucleons belonging to different nuclei and the Pauli principle give the essential contribution into the nucleus-nucleus potential at distances, when nuclei are strongly overlapping, and lead to appearance of the repulsive core of nucleus nucleus interaction at small distances between nuclei.

Disassembly Control of Saccharide-Based Amphiphiles Driven by Electrostatic Repulsion.

Science.gov (United States)

Yamada, Taihei; Kokado, Kenta; Sada, Kazuki

2017-03-14

According to the design of disassembly using electrostatic repulsion, novel amphiphiles consisting of a lipophilic ion part and a hydrophilic saccharide part were synthesized via the facile copper-catalyzed click reaction, and their molecular assemblies in water and chloroform were studied. The amphiphiles exhibited a molecular orientation opposite to that of the conventional amphiphiles in each case. ζ Potential measurements indicated that the lipophilic ion part is exposed outside in chloroform. The size of a solvophobic part in the amphiphiles dominates the size of an assembling structure; that is, in water, these amphiphiles tethering different lengths of the saccharide part exhibited almost identical assembling size, whereas in chloroform, the size depends on the length of the saccharide part in the amphiphiles.

Design of Multi Objectives Control Systems to Control Nuclear Reactor Power

International Nuclear Information System (INIS)

Abdelaal, M.M.Z.

2013-01-01

The Egyptian Testing Research Reactor (ETRR-2) nonlinear twelfth order model is linearized and reduced to lower order model. Model order reduction methodologies such as balanced truncation, Schur reduction method, Hankel approximation and Coprime factorization have been used in the reduction process. The reactor actually controlled by PD controller with fixed tuning parameters. LMI state feedback, LMI-pool assignment, H ∞ and observer based controllers based third order model are proposed to be used in the reactor power control instead of the PD controller. A comparison of LMI, LMI-Pole placement,H ∞ control systems and those of based observer relative to the PD controller has been performed which showed better response and disturbance rejection for the proposed controllers.

Preparation and Characterization of Nanofibrillated Cellulose from Bamboo Fiber via Ultrasonication Assisted by Repulsive Effect

Directory of Open Access Journals (Sweden)

Zhijun Hu

2017-01-01

Full Text Available Nanofibrillated celluloses (NFCs have recently drawn much attention because of their exceptional physicochemical properties. However, the existing preparation procedures either produce low yields or severely degrade the cellulose and, moreover, are not energy efficient. The purpose of this study was to develop a novel process using ultrasonic homogenization to isolate fibrils from bamboo fiber (BF with the assistance of negatively charged entities. The obtained samples were characterized by the degree of substitution (DS of carboxymethyl, Fourier-transform infrared (FT-IR spectroscopy, X-ray diffraction (XRD, thermogravimetric analysis, and transmission electron microscopy (TEM. The results showed that an NFC yield could be obtained above 70% through this route. The enzyme hydrolysis could enhance the surface charge of the fiber, and mechanical activation facilitates an increase in the DS. The disintegrating efficiency of the cellulose fibrils significantly depended on the input power of ultrasonication and the DS. FT-IR spectra confirmed the occurrence of the carboxymethylation reaction based on the appearance of the characteristic signal for the carboxyl group. From XRD analysis, it was observed that the presence of the carboxyl groups makes the isolation more efficient attributed to the ionic repulsion between the carboxylate groups of the cellulose chains.

Pairing from dynamically screened Coulomb repulsion in bismuth

Science.gov (United States)

Ruhman, Jonathan; Lee, Patrick A.

2017-12-01

Recently, Prakash et al. have discovered bulk superconductivity in single crystals of bismuth, which is a semimetal with extremely low carrier density. At such low density, we argue that conventional electron-phonon coupling is too weak to be responsible for the binding of electrons into Cooper pairs. We study a dynamically screened Coulomb interaction with effective attraction generated on the scale of the collective plasma modes. We model the electronic states in bismuth to include three Dirac pockets with high velocity and one hole pocket with a significantly smaller velocity. We find a weak-coupling instability, which is greatly enhanced by the presence of the hole pocket. Therefore we argue that bismuth is the first material to exhibit superconductivity driven by retardation effects of Coulomb repulsion alone. By using realistic parameters for bismuth we find that the acoustic plasma mode does not play the central role in pairing. We also discuss a matrix element effect, resulting from the Dirac nature of the conduction band, which may affect Tc in the s -wave channel without breaking time-reversal symmetry.

Repulsion analysis of permanent magnets for the Hoop energy storage system

International Nuclear Information System (INIS)

O, B. H.; Cho, S. B.; Kim, D. I.

1996-01-01

The repulsion force of permanent magnets is studied in order to analyze the instability problem of the rotational motion of a hoop levitated by permanent magnets in the Hoop Energy Storage System (HESS). The hoop of permanent magnets is levitated to remove the mechanical complexities caused by the rotational axis. It is important to maintain stable rotational motion at any speed for the efficiency as well as the safety of the system. To set up the equations of motion, the force of levitation and the source of perturbation are represented in terms of real parameters of the permanent magnets. The instability conditions and various geometric effects of the permanent magnets are analyzed. (author)

Off-shell sensitivity, repulsive correlations and the pion-nucleus optical potential

Energy Technology Data Exchange (ETDEWEB)

Keister, B D [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA). Dept. of Physics

1977-07-01

Repulsive nucleon-nucleon correlations tend to reduce the dependence of pion-nucleus elastic scattering upon the off-shell pion-nucleon dynamics. However, optical potential calculations can in practice be quite sensitive to the particular choice of off-shell model parameters. It is argued that this sensitivity results from the nature of the optical potential as a one-body operator which introduces extra off-shell dependence not found in physical many-body process itself. Thus, one must be very careful in any attempt to extract correlation or off-shell information, or to predict pion-nucleus phase shifts, by means of an optical potential theory. Results of model calculations are presented for purposes of illustration.

Time delay induced different synchronization patterns in repulsively coupled chaotic oscillators

Science.gov (United States)

Yao, Chenggui; Yi, Ming; Shuai, Jianwei

2013-09-01

Time delayed coupling plays a crucial role in determining the system's dynamics. We here report that the time delay induces transition from the asynchronous state to the complete synchronization (CS) state in the repulsively coupled chaotic oscillators. In particular, by changing the coupling strength or time delay, various types of synchronous patterns, including CS, antiphase CS, antiphase synchronization (ANS), and phase synchronization, can be generated. In the transition regions between different synchronous patterns, bistable synchronous oscillators can be observed. Furthermore, we show that the time-delay-induced phase flip bifurcation is of key importance for the emergence of CS. All these findings may light on our understanding of neuronal synchronization and information processing in the brain.

Inquiry into thermodynamic behavior of hard sphere plus repulsive barrier of finite height.

Science.gov (United States)

Zhou, Shiqi; Solana, J R

2009-11-28

A bridge function approximation is proposed to close the Ornstein-Zernike (OZ) integral equation for fluids with purely repulsive potentials. The performance of the bridge function approximation is then tested by applying the approximation to two kinds of repulsive potentials, namely, the square shoulder potential and the triangle shoulder potential. An extensive comparison between simulation and the OZ approach is performed over a wide density range for the fluid phase and several temperatures. It is found that the agreement between the two routes is excellent for not too low temperatures and satisfactory for extremely low temperatures. Then, this globally trustworthy OZ approach is used to investigate the possible existence or not of a liquid anomaly, i.e., a liquid-liquid phase transition at low temperatures and negative values of the thermal expansion coefficient in certain region of the phase diagram. While the existence of the liquid anomaly in the square shoulder potential has been previously predicted by a traditional first-order thermodynamic perturbation theory (TPT), the present investigation indicates that the liquid-liquid phase transition disappears in the OZ approach, so that its prediction by the first-order TPT is only an artifact originating from the low temperature inadequacy of the first-order TPT. However, the OZ approach indeed predicts negative thermal expansion coefficients. The present bridge function approximation, free of adjustable parameters, is suitable to be used within the context of a recently proposed nonhard sphere perturbation scheme.

Raman non-coincidence effect of boroxol ring: The interplay between repulsion and attraction forces in the glassy, supercooled and liquid state

Science.gov (United States)

Kalampounias, Angelos G.; Papatheodorou, George N.

2018-06-01

Temperature dependent Raman spectra of boric oxide have been measured in a temperature range covering the glassy, supercooled and liquid state. The shift of the isotropic band assigned to boroxol rings relative to the anisotropic component upon heating the glass is measured and attributed to the Raman non-coincidence effect. The measured shift is associated with the competition between attraction and repulsion forces with increasing temperature. The relation of dephasing and orientational relaxation times to the non-coincidence effect of the condensed phases has been examined. We discuss our results in the framework of the current phenomenological status of the field in an attempt to separate the attraction and repulsion contributions corresponding to the observed non-coincidence effect.

Synchronisation Induced by Repulsive Interactions in a System of van der Pol Oscillators

Science.gov (United States)

Martins, T. V.; Toral, R.

2011-09-01

We consider a system of identical van der Pol oscillators, globally coupled through their velocities, and study how the presence of competitive interactions affects its synchronisation properties. We will address the question from two points of view. Firstly, we will investigate the role of competitive interactions on the synchronisation among identical oscillators. Then, we will show that the presence of a fraction of repulsive links results in the appearance of macroscopic oscillations at that signal's rhythm, in regions where the individual oscillator is unable to synchronise with a weak external signal.

Repulsive four-body interactions of α particles and quasistable nuclear α -particle condensates in heavy self-conjugate nuclei

Science.gov (United States)

Bai, Dong; Ren, Zhongzhou

2018-05-01

We study the effects of repulsive four-body interactions of α particles on nuclear α -particle condensates in heavy self-conjugate nuclei using a semianalytic approach, and find that the repulsive four-body interactions could decrease the critical number of α particles, beyond which quasistable α -particle condensate states can no longer exist, even if these four-body interactions make only tiny contributions to the total energy of the Hoyle-like state of 16O. Explicitly, we study eight benchmark parameter sets, and find that the critical number Ncr decreases by |Δ Ncr|˜1 -4 from Ncr˜11 with vanishing four-body interactions. We also discuss the effects of four-body interactions on energies and radii of α -particle condensates. Our study can be useful for future experiments to study α -particle condensates in heavy self-conjugate nuclei. Also, the experimental determination of Ncr will eventually help establish a better understanding on the α -particle interactions, especially the four-body interactions.

Son of sevenless directly links the Robo receptor to rac activation to control axon repulsion at the midline.

Science.gov (United States)

Yang, Long; Bashaw, Greg J

2006-11-22

Son of sevenless (Sos) is a dual specificity guanine nucleotide exchange factor (GEF) that regulates both Ras and Rho family GTPases and thus is uniquely poised to integrate signals that affect both gene expression and cytoskeletal reorganization. Here, using genetics, biochemistry, and cell biology, we demonstrate that Sos is recruited to the plasma membrane, where it forms a ternary complex with the Roundabout receptor and the SH3-SH2 adaptor protein Dreadlocks (Dock) to regulate Rac-dependent cytoskeletal rearrangement in response to the Slit ligand. Intriguingly, the Ras and Rac-GEF activities of Sos can be uncoupled during Robo-mediated axon repulsion; Sos axon guidance function depends on its Rac-GEF activity, but not its Ras-GEF activity. These results provide in vivo evidence that the Ras and RhoGEF domains of Sos are separable signaling modules and support a model in which Robo recruits Sos to the membrane via Dock to activate Rac during midline repulsion.

Energy-level repulsion by spin-orbit coupling in two-dimensional Rydberg excitons

Science.gov (United States)

Stephanovich, V. A.; Sherman, E. Ya.; Zinner, N. T.; Marchukov, O. V.

2018-05-01

We study the effects of Rashba spin-orbit coupling on two-dimensional Rydberg exciton systems. Using analytical and numerical arguments we demonstrate that this coupling considerably modifies the wave functions and leads to a level repulsion that results in a deviation from the Poissonian statistics of the adjacent level distance distribution. This signifies the crossover to nonintegrability of the system and hints at the possibility of quantum chaos emerging. Such behavior strongly differs from the classical realization, where spin-orbit coupling produces highly entangled, chaotic electron trajectories in an exciton. We also calculate the oscillator strengths and show that randomization appears in the transitions between states with different total momenta.

Effect of long-range repulsive Coulomb interactions on packing structure of adhesive particles.

Science.gov (United States)

Chen, Sheng; Li, Shuiqing; Liu, Wenwei; Makse, Hernán A

2016-02-14

The packing of charged micron-sized particles is investigated using discrete element simulations based on adhesive contact dynamic model. The formation process and the final obtained structures of ballistic packings are studied to show the effect of interparticle Coulomb force. It is found that increasing the charge on particles causes a remarkable decrease of the packing volume fraction ϕ and the average coordination number 〈Z〉, indicating a looser and chainlike structure. Force-scaling analysis shows that the long-range Coulomb interaction changes packing structures through its influence on particle inertia before they are bonded into the force networks. Once contact networks are formed, the expansion effect caused by repulsive Coulomb forces are dominated by short-range adhesion. Based on abundant results from simulations, a dimensionless adhesion parameter Ad*, which combines the effects of the particle inertia, the short-range adhesion and the long-range Coulomb interaction, is proposed and successfully scales the packing results for micron-sized particles within the latest derived adhesive loose packing (ALP) regime. The structural properties of our packings follow well the recent theoretical prediction which is described by an ensemble approach based on a coarse-grained volume function, indicating some kind of universality in the low packing density regime of the phase diagram regardless of adhesion or particle charge. Based on the comprehensive consideration of the complicated inter-particle interactions, our findings provide insight into the roles of short-range adhesion and repulsive Coulomb force during packing formation and should be useful for further design of packings.

Repulsive atomic gas in a harmonic trap on the border of itinerant ferromagnetism.

Science.gov (United States)

Conduit, G J; Simons, B D

2009-11-13

Alongside superfluidity, itinerant (Stoner) ferromagnetism remains one of the most well-characterized phases of correlated Fermi systems. A recent experiment has reported the first evidence for novel phase behavior on the repulsive side of the Feshbach resonance in a two-component ultracold Fermi gas. By adapting recent theoretical studies to the atomic trap geometry, we show that an adiabatic ferromagnetic transition would take place at a weaker interaction strength than is observed in experiment. This discrepancy motivates a simple nonequilibrium theory that takes account of the dynamics of magnetic defects and three-body losses. The formalism developed displays good quantitative agreement with experiment.

Exact results for the many-body problem in one dimension with repulsive delta-function interaction

International Nuclear Information System (INIS)

Yang, C.N.

1983-01-01

The repulsive δ interaction problem in one dimension for N particles is reduced, through the use of Bethe's hypothesis, to an eigenvalue problem of matrices of the same sizes as the irreducible representations R of the permutation group S/sub N/. For some R's this eigenvalue problem itself is solved by a second use of Bethe's hypothesis, in a generalized form. In particular, the ground-state problem of spin-1/2 fermions is reduced to a generalized Fredholm equation

Energy and climate policy in China's twelfth five-year plan: A paradigm shift

International Nuclear Information System (INIS)

Li Jun; Wang Xin

2012-01-01

The twelfth five-year plan (FYP) endorsed by the People's National Congress in March 2011 plays a crucial role in shaping China's development trajectory over the next decades , and especially for the fulfillment of the 40–45 carbon intensity reduction target by 2020. The plan will condition both the medium and long term perspectives of economic restructuring, rebalance between the inclusive economic growth and environmental objectives, which are compounded by multiple constraints faced by China such as aging population, natural resources depletion, energy supply security and environmental deterioration. This article investigates the major energy and climate targets and actions specified in the 12th FYP to gain insights into the nature and magnitude of challenges and difficulties with regard to the medium and long run economic and environmental policies. It points out that China should articulate sectoral policies with the global climate mitigation targets to avoid long term carbon lock-in. Based on an in-depth analysis of the objectives in the plan, it is argued that the implementation should include mainstreaming developments of appropriate instruments to support cost-effective energy efficiency improvements and carbon intensity reduction in the next five years. - Highlights: ► We investigate the major energy and climate targets and actions specified in the Chinese 12th FYP. ► It points out FYP's implications for energy policy and global climate stabilisation. ► Challenges and difficulties with regard to the medium and long run climate strategies. ► Shift from investment and export-led to consumption led sustainable and inclusive growth model.

First-passage dynamics of linear stochastic interface models: numerical simulations and entropic repulsion effect

Science.gov (United States)

Gross, Markus

2018-03-01

A fluctuating interfacial profile in one dimension is studied via Langevin simulations of the Edwards–Wilkinson equation with non-conserved noise and the Mullins–Herring equation with conserved noise. The profile is subject to either periodic or Dirichlet (no-flux) boundary conditions. We determine the noise-driven time-evolution of the profile between an initially flat configuration and the instant at which the profile reaches a given height M for the first time. The shape of the averaged profile agrees well with the prediction of weak-noise theory (WNT), which describes the most-likely trajectory to a fixed first-passage time. Furthermore, in agreement with WNT, on average the profile approaches the height M algebraically in time, with an exponent that is essentially independent of the boundary conditions. However, the actual value of the dynamic exponent turns out to be significantly smaller than predicted by WNT. This ‘renormalization’ of the exponent is explained in terms of the entropic repulsion exerted by the impenetrable boundary on the fluctuations of the profile around its most-likely path. The entropic repulsion mechanism is analyzed in detail for a single (fractional) Brownian walker, which describes the anomalous diffusion of a tagged monomer of the interface as it approaches the absorbing boundary. The present study sheds light on the accuracy and the limitations of the weak-noise approximation for the description of the full first-passage dynamics.

Inverse Estimation of Surface Radiation Properties Using Repulsive Particle Swarm Optimization Algorithm

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyun Ho [Sejong University, Sejong (Korea, Republic of); Kim, Ki Wan [Agency for Defense Development, Daejeon (Korea, Republic of)

2014-09-15

The heat transfer mechanism for radiation is directly related to the emission of photons and electromagnetic waves. Depending on the participation of the medium, the radiation can be classified into two forms: surface and gas radiation. In the present study, unknown radiation properties were estimated using an inverse boundary analysis of surface radiation in an axisymmetric cylindrical enclosure. For efficiency, a repulsive particle swarm optimization (RPSO) algorithm, which is a relatively recent heuristic search method, was used as inverse solver. By comparing the convergence rates and accuracies with the results of a genetic algorithm (GA), the performances of the proposed RPSO algorithm as an inverse solver was verified when applied to the inverse analysis of the surface radiation problem.

Inverse Estimation of Surface Radiation Properties Using Repulsive Particle Swarm Optimization Algorithm

International Nuclear Information System (INIS)

Lee, Kyun Ho; Kim, Ki Wan

2014-01-01

The heat transfer mechanism for radiation is directly related to the emission of photons and electromagnetic waves. Depending on the participation of the medium, the radiation can be classified into two forms: surface and gas radiation. In the present study, unknown radiation properties were estimated using an inverse boundary analysis of surface radiation in an axisymmetric cylindrical enclosure. For efficiency, a repulsive particle swarm optimization (RPSO) algorithm, which is a relatively recent heuristic search method, was used as inverse solver. By comparing the convergence rates and accuracies with the results of a genetic algorithm (GA), the performances of the proposed RPSO algorithm as an inverse solver was verified when applied to the inverse analysis of the surface radiation problem

Non-spherical particle formation induced by repulsive hydration forces during spray drying

Energy Technology Data Exchange (ETDEWEB)

Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong, E-mail: hdjang@kigam.re.kr; Cho, Kuk, E-mail: kukcho@pusan.ac.kr [Korea Institute of Geoscience and Mineral Resources (Korea, Republic of)

2013-09-15

Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO{sub 2}, TiO{sub 2}, and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying.

Non-spherical particle formation induced by repulsive hydration forces during spray drying

International Nuclear Information System (INIS)

Suh, Yong Jae; Lee, Jin-Woo; Chang, Hankwon; Jang, Hee-Dong; Cho, Kuk

2013-01-01

Non-spherical particles were produced during a spray-drying process, but the exact mechanism of their formation was unknown. The non-spherical particles form when the strength of the colloidal droplets is exceeded by external stress stemming from drag in the velocity gradient. Here, we show that repulsive hydration forces reduce the mechanical strength of the droplets; this is critical to the formation of non-spherical particles. Toroidal or ellipsoidal particles were prepared from low-concentration hydrophilic SiO 2 , TiO 2 , and CuO colloidal solutions, but not from hydrophobic ZnO colloidal solutions. The surface properties of the solid particulates are crucial for the morphology of particles formed during spray drying

Spin–orbit coupling, minimal model and potential Cooper-pairing from repulsion in BiS2-superconductors

Science.gov (United States)

Cobo-Lopez, Sergio; Saeed Bahramy, Mohammad; Arita, Ryotaro; Akbari, Alireza; Eremin, Ilya

2018-04-01

We develop the realistic minimal electronic model for recently discovered BiS2 superconductors including the spin–orbit (SO) coupling based on the first-principles band structure calculations. Due to strong SO coupling, characteristic for the Bi-based systems, the tight-binding low-energy model necessarily includes p x , p y , and p z orbitals. We analyze a potential Cooper-pairing instability from purely repulsive interaction for the moderate electronic correlations using the so-called leading angular harmonics approximation. For small and intermediate doping concentrations we find the dominant instabilities to be {d}{x2-{y}2}-wave, and s ±-wave symmetries, respectively. At the same time, in the absence of the sizable spin fluctuations the intra and interband Coulomb repulsions are of the same strength, which yield the strongly anisotropic behavior of the superconducting gaps on the Fermi surface. This agrees with recent angle resolved photoemission spectroscopy findings. In addition, we find that the Fermi surface topology for BiS2 layered systems at large electron doping can resemble the doped iron-based pnictide superconductors with electron and hole Fermi surfaces maintaining sufficient nesting between them. This could provide further boost to increase T c in these systems.

A novel method for investigating the repulsive and attractive parts of cubic equations of state and the combining rules used with the vdW-1f theory

DEFF Research Database (Denmark)

Kontogeorgis, Georgios; Philippos, Coutsikos; Vassilis, Harismiadis

1998-01-01

A novel method for investigating the performance of the repulsive and attractive terms of a cubic equation of state (EoS) along with different combining rules for the cross covolume (b(12)) and cross-energy (a(12)) parameters used with the van der Waals one-fluid theory is presented. The method...... utilizes the EoS-derived liquid-phase activity coefficient which is separated into a combinatorial-free volume part (gamma(c-fv)), obtained from the repulsive term of the EoS, and a residual one (gamma(res)) obtained from the attractive term. Athermal systems (alkane solutions) are used where we can......(c-fv) values with the experimental ones suggest that the van der Waals (vdW) repulsive term is applicable not only to mixtures with spherical molecules, as originally suggested by van der Waals, but also to very asymmetric ones. On the other hand, the attractive term leads to gamma(res) values that can...

Thermal algebraic-decay charge liquid driven by competing short-range Coulomb repulsion

Science.gov (United States)

Kaneko, Ryui; Nonomura, Yoshihiko; Kohno, Masanori

2018-05-01

We explore the possibility of a Berezinskii-Kosterlitz-Thouless-like critical phase for the charge degrees of freedom in the intermediate-temperature regime between the charge-ordered and disordered phases in two-dimensional systems with competing short-range Coulomb repulsion. As the simplest example, we investigate the extended Hubbard model with on-site and nearest-neighbor Coulomb interactions on a triangular lattice at half filling in the atomic limit by using a classical Monte Carlo method, and find a critical phase, characterized by algebraic decay of the charge correlation function, belonging to the universality class of the two-dimensional XY model with a Z6 anisotropy. Based on the results, we discuss possible conditions for the critical phase in materials.

Development of an innovative reflector drive mechanism using magnetic repulsion force for 4S reactor

International Nuclear Information System (INIS)

Tsuji, K.; Watanabe, M.; Inagaki, H.; Nishikawa, A.; Takahashi, H.; Wakamatsu, M.; Matsumiya, H.; Nishiguchi, Y.

2001-01-01

A small sized fast reactor 4S: (Super Safe Small and Simple) which has a core of 10 - 30 years life time is controlled by reflectors. The reflector is required to be risen at very low speed to make up for the reactivity swing during operation. This report shows the development of an innovative reflector drive mechanism using magnetic repulsion force that can move at a several micrometer per one step. This drive mechanism has a passive shut down capability, and can eliminate reflector drive line. (author)

Differential elastic scattering of He* (21S) by Ar, Kr and Xe: Repulsive rainbows and optical potentials

International Nuclear Information System (INIS)

Martin, D.W.; Gregor, R.W.; Jordan, R.M.; Siska, P.E.

1978-01-01

Elastic scattering angular distributions of He* (2 1 S) with Ar, Kr, and Xe measured in crossed atomic beams at collision energies from 0.4--2.8 kcal/mole are analyzed using a physically motivated optical potential model. The resulting potentials show some features expected on the basis of the analogous Li--rare gas potentials: monotonically increasing van der Waals well depths epsilon in the sequence Ar, Kr, Xe, and nearly constant well position r/sub m/. However, structure occurs in the repulsive parts of the potentials in the form of a local slope maximum (force minimum) at low positive potential energy, as suggested by other studies. The potential energy at the slope maximum decreases monotonically in the Ar, Kr, Xe sequence, while its position increases monotonically. The slope maximum is manifested in the angular distributions through the appearance of rainbow scattering peaks for Ar and Kr at angles well removed from those at which attractive rainbows are expected, with both repulsive and attractive rainbows evident in the same distribution. The resonance widths are constrained to be simple exponentials. Table I contains all potential parameters derived. Reasonably good agreement is obtained between measured total ionization cross sections and quenching rate constants and those calculated from the optical potentials

Understanding valence-shell electron-pair repulsion (VSEPR) theory using origami molecular models

International Nuclear Information System (INIS)

Saraswati, Teguh Endah; Saputro, Sulistyo; Ramli, Murni; Praseptiangga, Danar; Khasanah, Nurul; Marwati, Sri

2017-01-01

Valence-shell electron-pair repulsion (VSEPR) theory is conventionally used to predict molecular geometry. However, it is difficult to explore the full implications of this theory by simply drawing chemical structures. Here, we introduce origami modelling as a more accessible approach for exploration of the VSEPR theory. Our technique is simple, readily accessible and inexpensive compared with other sophisticated methods such as computer simulation or commercial three-dimensional modelling kits. This method can be implemented in chemistry education at both the high school and university levels. We discuss the example of a simple molecular structure prediction for ammonia (NH 3 ). Using the origami model, both molecular shape and the scientific justification can be visualized easily. This ‘hands-on’ approach to building molecules will help promote understanding of VSEPR theory. (paper)

Understanding valence-shell electron-pair repulsion (VSEPR) theory using origami molecular models

Science.gov (United States)

Endah Saraswati, Teguh; Saputro, Sulistyo; Ramli, Murni; Praseptiangga, Danar; Khasanah, Nurul; Marwati, Sri

2017-01-01

Valence-shell electron-pair repulsion (VSEPR) theory is conventionally used to predict molecular geometry. However, it is difficult to explore the full implications of this theory by simply drawing chemical structures. Here, we introduce origami modelling as a more accessible approach for exploration of the VSEPR theory. Our technique is simple, readily accessible and inexpensive compared with other sophisticated methods such as computer simulation or commercial three-dimensional modelling kits. This method can be implemented in chemistry education at both the high school and university levels. We discuss the example of a simple molecular structure prediction for ammonia (NH3). Using the origami model, both molecular shape and the scientific justification can be visualized easily. This ‘hands-on’ approach to building molecules will help promote understanding of VSEPR theory.

Atomic-batched tensor decomposed two-electron repulsion integrals

Science.gov (United States)

Schmitz, Gunnar; Madsen, Niels Kristian; Christiansen, Ove

2017-04-01

We present a new integral format for 4-index electron repulsion integrals, in which several strategies like the Resolution-of-the-Identity (RI) approximation and other more general tensor-decomposition techniques are combined with an atomic batching scheme. The 3-index RI integral tensor is divided into sub-tensors defined by atom pairs on which we perform an accelerated decomposition to the canonical product (CP) format. In a first step, the RI integrals are decomposed to a high-rank CP-like format by repeated singular value decompositions followed by a rank reduction, which uses a Tucker decomposition as an intermediate step to lower the prefactor of the algorithm. After decomposing the RI sub-tensors (within the Coulomb metric), they can be reassembled to the full decomposed tensor (RC approach) or the atomic batched format can be maintained (ABC approach). In the first case, the integrals are very similar to the well-known tensor hypercontraction integral format, which gained some attraction in recent years since it allows for quartic scaling implementations of MP2 and some coupled cluster methods. On the MP2 level, the RC and ABC approaches are compared concerning efficiency and storage requirements. Furthermore, the overall accuracy of this approach is assessed. Initial test calculations show a good accuracy and that it is not limited to small systems.

Gauche effect in 1,2-difluoroethane. Hyperconjugation, bent bonds, steric repulsion.

Science.gov (United States)

Goodman, Lionel; Gu, Hongbing; Pophristic, Vojislava

2005-02-17

Natural bond orbital deletion calculations show that whereas the gauche preference arises from vicinal hyperconjugative interaction between anti C-H bonds and C-F* antibonds, the cis C-H/C-F* interactions are substantial (approximately 25% of the anti interaction). The established significantly >60 degrees FCCF dihedral angle for the equilibrium conformer can then be rationalized in terms of the hyperconjugation model alone by taking into account both anti interactions that maximize near 60 degrees and the smaller cis interactions that maximize at a much larger dihedral angle. This explanation does not invoke repulsive forces to rationalize the 72 degrees equilibrium conformer angle. The relative minimum energy for the trans conformer is the consequence of a balance between decreasing hyperconjugative stabilization and decreasing steric destabilization as the FCCF torsional angle approaches 180 degrees . The torsional coordinate is predicted to be strongly contaminated by CCF bending, with the result that approximately half of the trans --> gauche stabilization energy stems from mode coupling.

Current quantization and fractal hierarchy in a driven repulsive lattice gas.

Science.gov (United States)

Rotondo, Pietro; Sellerio, Alessandro Luigi; Glorioso, Pietro; Caracciolo, Sergio; Cosentino Lagomarsino, Marco; Gherardi, Marco

2017-11-01

Driven lattice gases are widely regarded as the paradigm of collective phenomena out of equilibrium. While such models are usually studied with nearest-neighbor interactions, many empirical driven systems are dominated by slowly decaying interactions such as dipole-dipole and Van der Waals forces. Motivated by this gap, we study the nonequilibrium stationary state of a driven lattice gas with slow-decayed repulsive interactions at zero temperature. By numerical and analytical calculations of the particle current as a function of the density and of the driving field, we identify (i) an abrupt breakdown transition between insulating and conducting states, (ii) current quantization into discrete phases where a finite current flows with infinite differential resistivity, and (iii) a fractal hierarchy of excitations, related to the Farey sequences of number theory. We argue that the origin of these effects is the competition between scales, which also causes the counterintuitive phenomenon that crystalline states can melt by increasing the density.

Current quantization and fractal hierarchy in a driven repulsive lattice gas

Science.gov (United States)

Rotondo, Pietro; Sellerio, Alessandro Luigi; Glorioso, Pietro; Caracciolo, Sergio; Cosentino Lagomarsino, Marco; Gherardi, Marco

2017-11-01

Driven lattice gases are widely regarded as the paradigm of collective phenomena out of equilibrium. While such models are usually studied with nearest-neighbor interactions, many empirical driven systems are dominated by slowly decaying interactions such as dipole-dipole and Van der Waals forces. Motivated by this gap, we study the nonequilibrium stationary state of a driven lattice gas with slow-decayed repulsive interactions at zero temperature. By numerical and analytical calculations of the particle current as a function of the density and of the driving field, we identify (i) an abrupt breakdown transition between insulating and conducting states, (ii) current quantization into discrete phases where a finite current flows with infinite differential resistivity, and (iii) a fractal hierarchy of excitations, related to the Farey sequences of number theory. We argue that the origin of these effects is the competition between scales, which also causes the counterintuitive phenomenon that crystalline states can melt by increasing the density.

Modulating the Electrochemical Performances of Layered Cathode Materials for Sodium Ion Batteries through Tuning Coulombic Repulsion between Negatively Charged TMO2 Slabs.

Science.gov (United States)

Li, Zheng-Yao; Wang, Huibo; Yang, Wenyun; Yang, Jinbo; Zheng, Lirong; Chen, Dongfeng; Sun, Kai; Han, Songbai; Liu, Xiangfeng

2018-01-17

Exploiting advanced layered transition metal oxide cathode materials is of great importance to rechargeable sodium batteries. Layered oxides are composed of negatively charged TMO 2 slabs (TM = transition metal) separated by Na + diffusion layers. Herein, we propose a novel insight, for the first time, to control the electrochemical properties by tuning Coulombic repulsion between negatively charged TMO 2 slabs. Coulombic repulsion can finely tailor the d-spacing of Na ion layers and material structural stability, which can be achieved by employing Na + cations to serve as effective shielding layers between TMO 2 layers. A series of O3-type Na x Mn 1/3 Fe 1/3 Cu 1/6 Mg 1/6 O 2 (x = 1.0, 0.9, 0.8, and 0.7) have been prepared, and Na 0.7 Mn 1/3 Fe 1/3 Cu 1/6 Mg 1/6 O 2 shows the largest Coulombic repulsion between TMO 2 layers, the largest space for Na ion diffusion, the best structural stability, and also the longest Na-O chemical bond with weaker Coulombic attraction, thus leading to the best electrochemical performance. Meanwhile, the thermal stability depends on the Na concentration in pristine materials. Ex situ X-ray absorption (XAS) analysis indicates that Mn, Fe, and Cu ions are all electrochemically active components during insertion and extraction of sodium ion. This study enables some new insights to promote the development of advanced layered Na x TMO 2 materials for rechargeable sodium batteries in the future.

Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties

OpenAIRE

Palacios, M.; Bowen, P.; Kappl, M.; Butt, H. J.; Stuer, M.; Pecharromán, C.; Aschauer, U.; Puertas, F.

2012-01-01

The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag using colloidal probe atomi...

New exact solutions of Einstein's field equations: gravitational force can also be repulsive!

International Nuclear Information System (INIS)

Dietz, W.

1988-01-01

This article has not been written for specialists of exact solutions of Einstein's field equations but for physicists who are interested in nontrivial information on this topic. We recall the history and some basic properties of exact solutions of Einstein's vacuum equations. We show that the field equations for stationary axisymmetric vacuum gravitational fields can be expressed by only one nonlinear differential equation for a complex function. This compact form of the field equations allows the generation of almost all stationary axisymmetric vacuum gravitational fields. We present a new stationary two-body solution of Einstein's equations as an application of this generation technique. This new solution proves the existence of a macroscopic, repulsive spin-spin interaction in general relativity. Some estimates that are related to this new two-body solution are given

Elementary process theory: a formal axiomatic system with a potential application as a foundational framework for physics supporting gravitational repulsion of matter and antimatter

International Nuclear Information System (INIS)

Cabbolet, M.J.T.F.

2010-01-01

Theories of modern physics predict that antimatter having rest mass will be attracted by the earth's gravitational field, but the actual coupling of antimatter with gravitation has not been established experimentally. The purpose of the present research was to identify laws of physics that would govern the universe if antimatter having rest mass would be repulsed by the earth's gravitational field. As a result, a formalized axiomatic system was developed together with interpretation rules for the terms of the language: the intention is that every theorem of the system yields a true statement about physical reality. Seven non-logical axioms of this axiomatic system form the elementary process theory (EPT): this is then a scheme of elementary principles describing the dynamics of individual processes taking place at supersmall scale. It is demonstrated how gravitational repulsion functions in the universe of the EPT, and some observed particles and processes have been formalized in the framework of the EPT. Incompatibility of quantum mechanics (QM) and General Relativity (GR) with the EPT is proven mathematically; to demonstrate applicability to real world problems to which neither QM nor GR applies, the EPT has been applied to a theory of the Planck era of the universe. The main conclusions are that a completely formalized framework for physics has been developed supporting the existence of gravitational repulsion and that the present results give rise to a potentially progressive research program. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Chromatid repulsion associated with Roberts/SC phocomelia syndrome is reduced in malignant cells and not expressed in interspecies somatic-cell hybrids.

Science.gov (United States)

Krassikoff, N E; Cowan, J M; Parry, D M; Francke, U

1986-01-01

Different cell types from a female patient with Roberts/SC phocomelia syndrome were evaluated quantitatively for the presence of repulsion of heterochromatin and satellite regions of mitotic chromosomes. Whereas EBV-transformed lymphoblasts from an established cell line revealed these phenomena at frequencies equal to those in PHA-stimulated lymphocytes and cultured skin fibroblasts, aneuploid cells from a metastatic melanoma displayed them at 50% lower frequency. Cocultivation of the patient's fibroblasts with either an immortal Chinese hamster cell line or with a human male fibroblast strain carrying a t(4;6)(p14;q21) translocation showed that the phenomenon was not corrected or induced by a diffusible factor or by cell-to-cell contact. In each experiment, only the patient's metaphase spreads revealed chromatid repulsion. In fusion hybrids between the patient's fibroblasts and an established Chinese hamster cell line, the human chromosomes behaved perfectly normally, suggesting that the gene product which is missing or mutant in Roberts/SC phocomelia syndrome is supplied by the Chinese hamster genome. Images Fig. 1 Fig. 2 Fig. 3 PMID:3788975

Shakespeare revisité, entre fidélité et parodie : de La Nuit des Rois à Shake de Dan Jemmett Shakespeare Revisited, Between Fidelity and Parody: From Twelfth Night to Shake by Dan Jemmett

Directory of Open Access Journals (Sweden)

Isabelle Schwartz-Gastine

2009-11-01

Full Text Available William Shakespeare himself was a master of re-writing older material as he abundantly used this technique, which was totally justified at the Renaissance, to compose his poems or plays, from various sources whether literary (prose or verse, historical, or any other—and sometimes most unusual—background.The play I am considering in this paper is a very recent re-writing in English by Dan Jemmett (Peter Brook’s son-in-law, but performed in Marie-Paul Remo’s French translation at the Vidy Theatre in Lausanne during the 2001 season. It is called Shake, with a modest sub-title « around Twelfth Night », but which is indeed at the heart of the topic.Through the exploration of three themes: symmetry (of situations, of twin binarities, love’s misunderstanding, and music, I will argue that this comedy, whose title is a mix between the name of the Bard and the etymological meaning of the verb “to shake” as far as traditions are concerned, is faithful to the spirit (rather than the letter of the Shakespearean original in a very healthy comic vein.It is not worth wondering if the spectators fully understood the meaning of this comedy in which the four actors change roles all the time: their frequent bursts of laughter clearly showed that they enjoyed the spirit of the comedy, whether they knew Twelfth Night or not.

Nuclides and isotopes. Twelfth edition

International Nuclear Information System (INIS)

Anon.

1977-01-01

This explanatory booklet was designed to be used with the Chart of the Nuclides. It contains a brief history of the atomic theory of matter: ancient speculations, periodic properties of elements (Mendeleev table), radioactivity, early models of atomic structure, the Bohr atom, quantum numbers, nature of isotopes, artificial radioactivity, and neutron fission. Information on the pre-Fermi (natural) nuclear reactor at Oklo and the search for superheavy elements is given. The booklet also discusses information presented on the Chart and its coding: stable nuclides, metastable states, data display and color, isotopic abundances, neutron cross sections, spins and parities, fission yields, half-life variability, radioisotope power and production data, radioactive decay chains, and elements without names. The Periodic Table of the Elements is appended. 3 figures, 3 tables

Particle-Hole Asymmetry and Brightening of Solitons in a Strongly Repulsive Bose-Einstein Condensate

International Nuclear Information System (INIS)

Balakrishnan, Radha; Satija, Indubala I.; Clark, Charles W.

2009-01-01

We study solitary wave propagation in the condensate of a system of hard-core bosons with nearest-neighbor interactions. For this strongly repulsive system, the evolution equation for the condensate order parameter of the system, obtained using spin-coherent state averages, is different from the usual Gross-Pitaevskii equation (GPE). The system is found to support two kinds of solitons when there is a particle-hole imbalance: a dark soliton that dies out as the velocity approaches the sound velocity and a new type of soliton which brightens and persists all the way up to the sound velocity, transforming into a periodic wave train at supersonic speed. Analogous to the GPE soliton, the energy-momentum dispersion for both solitons is characterized by Lieb II modes.

Study of Concentrations of Available Cations and Anions in PM2.5 in the Air of Twelfth Region of Tehran City

Directory of Open Access Journals (Sweden)

Hossean Arfaeinia

2017-04-01

Full Text Available Background: In the last few decades, the city's air quality has become a major concern; especially there is strong evidence about health effects of particulate matter in urban communities.In addition to suspended particles concentration, the ionic part of suspended particles is also very important, So that some studies  ions like Sulfate is the reson of increasing the respiratory diseases.So the aim of this study was to study of concentration of PM2.5 particles and their ionic componentsincluding major anions and cations in twelfth region of Tehran city in 2013. Materials & Methods: This cross - sectional study was conducted in the air of twelfth region of Tehran. PM2.5 concentration was calculated with sampling by frmOMNITMAmbient Air Sampler with PTFE filter with a diameter of 47 mm and through the weight measurement.Concentration of anions and cations which had associated with PM2.5 particles was read after collected sample preparation and injection to device Ion Chromatography (IC Metrohm 850 model. Correlation matrix was calculated between anions and cations. Data analysis was carried out by Excel and SPSS version 18 and One-Way ANOVA test. Results: The mean daily concentration of PM2.5 particles was 19.41 µg/m3 during the study. One-Way ANOVA test showed a significant difference at the 0.05 level between PM2.5 concentrations on different days of the week. Concentrations for sodium, potassium, ammonium, calcium, magnesium, sulfate, nitrate, chloride were obtained 0.28, 0.06, 0.49, 0.87, 0.63, 56.3, 1.43 and 0.71 µg/m3, respectively, and no value was detected for fluoride and nitrite. Balance between anions and cations were calculated and the correlation coefficient (R2 were obtained 0.972 between the anions and cations. Conclusion The mean concentrations of PM2.5 was higher than the air standards in Iran and WHO guidelines (25 µg/m3 and EPA standards (35 µg/m3. In a study reported that the One-Way ANOVA test between particle

Long-lived force patterns and deformation waves at repulsive epithelial boundaries

Science.gov (United States)

Rodríguez-Franco, Pilar; Brugués, Agustí; Marín-Llauradó, Ariadna; Conte, Vito; Solanas, Guiomar; Batlle, Eduard; Fredberg, Jeffrey J.; Roca-Cusachs, Pere; Sunyer, Raimon; Trepat, Xavier

2017-10-01

For an organism to develop and maintain homeostasis, cell types with distinct functions must often be separated by physical boundaries. The formation and maintenance of such boundaries are commonly attributed to mechanisms restricted to the cells lining the boundary. Here we show that, besides these local subcellular mechanisms, the formation and maintenance of tissue boundaries involves long-lived, long-ranged mechanical events. Following contact between two epithelial monolayers expressing, respectively, EphB2 and its ligand ephrinB1, both monolayers exhibit oscillatory patterns of traction forces and intercellular stresses that tend to pull cell-matrix adhesions away from the boundary. With time, monolayers jam, accompanied by the emergence of deformation waves that propagate away from the boundary. This phenomenon is not specific to EphB2/ephrinB1 repulsion but is also present during the formation of boundaries with an inert interface and during fusion of homotypic epithelial layers. Our findings thus unveil a global physical mechanism that sustains tissue separation independently of the biochemical and mechanical features of the local tissue boundary.

Cell adhesion and growth enabled by biomimetic oligopeptide modification of a polydopamine-poly(ethylene oxide) protein repulsive surface

Czech Academy of Sciences Publication Activity Database

Musílková, Jana; Kotelnikov, Ilya; Novotná, Katarína; Pop-Georgievski, Ognen; Rypáček, František; Bačáková, Lucie; Proks, Vladimír

2015-01-01

Roč. 26, č. 11 (2015), s. 253 ISSN 0957-4530 R&D Projects: GA ČR(CZ) GAP108/11/1857; GA ČR(CZ) GAP108/12/1168; GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 ; RVO:61389013 Keywords : protein repulsive surface * cell adhesion * RGD * endothelial cells Subject RIV: EI - Biotechnology ; Bionics; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 2.272, year: 2015

Amplitude death induced by mixed attractive and repulsive coupling in the relay system

Science.gov (United States)

Zhao, Nannan; Sun, Zhongkui; Xu, Wei

2018-01-01

The amplitude death (AD) phenomenon is found in the relay system in the presence of the mixed couplings composed of attractive coupling and repulsive coupling. The generation mechanism of AD is revealed and shows that the middle oscillator achieving AD is a prerequisite to further suppress oscillation of the outermost oscillators for the paradigmatic Stuart-Landau and Rössler models. Moreover, regarding the Stuart-Landau relay system as a small motif of star network, we also observe that the mixed couplings can facilitate AD state of the whole network system. Particularly, the threshold of coupling strength is invariable with the change of network size. Our findings may shed a new insight to explore the effects of hybrid coupling on complex systems, also provide a new strategy to control dynamic behaviors in engineering science and neuroscience fields.

A conserved neuronal DAF-16/FoxO plays an important role in conveying pheromone signals to elicit repulsion behavior in Caenorhabditis elegans.

Science.gov (United States)

Park, Donha; Hahm, Jeong-Hoon; Park, Saeram; Ha, Go; Chang, Gyeong-Eon; Jeong, Haelim; Kim, Heekyeong; Kim, Sunhee; Cheong, Eunji; Paik, Young-Ki

2017-08-03

Animals use pheromones as a conspecific chemical language to respond appropriately to environmental changes. The soil nematode Caenorhabditis elegans secretes ascaroside pheromones throughout the lifecycle, which influences entry into dauer phase in early larvae, in addition to sexual attraction and aggregation. In adult hermaphrodites, pheromone sensory signals perceived by worms usually elicit repulsion as an initial behavioral signature. However, the molecular mechanisms underlying neuronal pheromone sensory process from perception to repulsion in adult hermaphrodites remain poorly understood. Here, we show that pheromone signals perceived by GPA-3 is conveyed through glutamatergic neurotransmission in which neuronal DAF-16/FoxO plays an important modulatory role by controlling glutaminase gene expression. We further provide evidence that this modulatory role for DAF-16/FoxO seems to be conserved evolutionarily by electro-physiological study in mouse primary hippocampal neurons that are responsible for glutamatergic neurotransmission. These findings provide the basis for understanding the nematode pheromone signaling, which seems crucial for adaptation of adult hermaphrodites to changes in environmental condition for survival.

Attractive and repulsive interactions among methanol molecules in supercritical state investigated by Raman spectroscopy and perturbed hard-sphere theory.

Science.gov (United States)

Saitow, Ken-ichi; Sasaki, Jungo

2005-03-08

The short-range structure of supercritical methanol (CH(3)OH) is investigated by measuring the spontaneous Raman spectra of the C-O stretching mode. The spectra are obtained at a reduced temperature, T(r)=T/T(c)=1.02 (522.9 K), which permits the neat fluid to be studied isothermally as a function of density. As the density increases, the spectral peaks shift toward the lower energy side and the spectra broaden. In the supercritical region, the amount of shifting shows nonlinear density dependence and the width becomes anomalously large. We use the perturbed hard-sphere model to analyze these density dependencies along the vibrational coordinate. The amount of shifting is decomposed into attractive and repulsive components, and the changes in attractive and repulsive energies are evaluated as functions of density and packing fraction, both of which are continuously varied by a factor of 120. Here we show that the shift amount consists principally of the attractive component at all densities, since the attractive energy is about eight times the repulsive energy. The density dependence of the widths is analyzed by calculating homogeneous and inhomogeneous widths as a function of density. The results show that, although vibrational dephasing and density inhomogeneity contribute similarly to the width at low and middle densities, at high density the main contributor turns out to be the vibrational dephasing. We estimate the local density enhancements of supercritical CH(3)OH as function of bulk density by two methods. The results of these analyses show common features, and both the estimated local density enhancements of CH(3)OH are considerably larger than the local density enhancements of simple fluids, i.e., those having nonhydrogen bonding. It is revealed that the local density of supercritical CH(3)OH is 40%-60% greater than the local densities of the simple fluids. We also estimate the local density fluctuation using the obtained values of attractive shift

Superconductivity in a Fermi liquid from repulsive interactions: The role of electron–phonon interaction

International Nuclear Information System (INIS)

Fan, J.D.; Malozovsky, Y.M.

2013-01-01

Highlights: • The sign reversal of pair interaction in momentum space is proved. • It is also shown that electron-phonon interaction in fact leads to the pairing-break effect. • Transition temperature into superconductivity depends on competition between electron-phonon and Coulomb interactions. • Calculated exponent α of the isotope effect shows the possibility equal to, greater or less than 0.5, and even negative. -- Abstract: Based on our previously proven theorem that the interaction between a pair of quasiparticles in the normal Fermi liquid has an opposite sign to the interaction between particles, we consider pair correlation between a pair of quasiparticles when the interaction between particles is repulsive. For the convenience of statements, we have presented in this article once again the proof of the theorem in terms of an exact equation for the thermodynamic potential due to interaction between particles and based on the Green’s function method. Further, we have derived the Landau expansion of the thermodynamic potentials in terms of the variation of the quasiparticle distribution function. We have also derived the expansion of the thermodynamic potential in terms of the variation of an exact single particle (not quasiparticles), these derivations lead to the relationship between the interaction function for two quasiparticles and the interaction energy between two particles as shown. According to the proven theorem the interaction between a pair of quasiparticles is attractive in this case, the pairing – Cooper’s pairing between a pair of quasiparticles is possible. We solve the Bethe–Salpeter type equation for paring of two quasiparticles when both interactions – the Coulomb repulsive and electron–phonon interaction are present. We show that the electron–phonon interaction, in fact, leads to the pair breaking effect, in contrast to the common belief that electron–phonon interaction is the main mechanism for Cooper’s pair

Bipolar outflows as a repulsive gravitational phenomenon - Azimuthally Symmetric Theory of Gravitation (II)

International Nuclear Information System (INIS)

Nyambuya, Golden Gadzirayi

2010-01-01

This paper is part of a series on the Azimuthally Symmetric Theory of Gravitation (ASTG). This theory is built on Laplace-Poisson's well known equation and it has been shown that the ASTG is capable of explaining, from a purely classical physics standpoint, the precession of the perihelion of solar planets as a consequence of the azimuthal symmetry emerging from the spin of the Sun. This symmetry has and must have an influence on the emergent gravitational field. We show herein that the emergent equations from the ASTG, under some critical conditions determined by the spin, do possess repulsive gravitational fields in the polar regions of the gravitating body in question. This places the ASTG on an interesting pedestal to infer the origins of outflows as a repulsive gravitational phenomenon. Outflows are a ubiquitous phenomenon found in star forming systems and their true origin is a question yet to be settled. Given the current thinking on their origin, the direction that the present paper takes is nothing short of an asymptotic break from conventional wisdom; at the very least, it is a complete paradigm shift because gravitation is not at all associated with this process, but rather it is thought to be an all-attractive force that only tries to squash matter together onto a single point. Additionally, we show that the emergent Azimuthally Symmetric Gravitational Field from the ASTG strongly suggests a solution to the supposed Radiation Problem that is thought to be faced by massive stars in their process of formation. That is, at ∼ 8-10 M sun , radiation from the nascent star is expected to halt the accretion of matter. We show that in-falling material will fall onto the equatorial disk and from there, this material will be channeled onto the forming star via the equatorial plane, thus accretion of mass continues well past the value of ∼ 8-10 M sun , albeit via the disk. Along the equatorial plane, the net force (with the radiation force included) on any

Condensed phase QM/MM simulations utilizing the exchange core functions to describe exchange repulsions at the QM boundary region

International Nuclear Information System (INIS)

Umino, Satoru; Takahashi, Hideaki; Morita, Akihiro

2016-01-01

In a recent work, we developed a method [H. Takahashi et al., J. Chem. Phys. 143, 084104 (2015)] referred to as exchange-core function (ECF) approach, to compute exchange repulsion E ex between solute and solvent in the framework of the quantum mechanical (QM)/molecular mechanical (MM) method. The ECF, represented with a Slater function, plays an essential role in determining E ex on the basis of the overlap model. In the work of Takahashi et al. [J. Chem. Phys. 143, 084104 (2015)], it was demonstrated that our approach is successful in computing the hydrogen bond energies of minimal QM/MM systems including a cationic QM solute. We provide in this paper the extension of the ECF approach to the free energy calculation in condensed phase QM/MM systems by combining the ECF and the QM/MM-ER approach [H. Takahashi et al., J. Chem. Phys. 121, 3989 (2004)]. By virtue of the theory of solutions in energy representation, the free energy contribution δμ ex from the exchange repulsion was naturally formulated. We found that the ECF approach in combination with QM/MM-ER gives a substantial improvement on the calculation of the hydration free energy of a hydronium ion. This can be attributed to the fact that the ECF reasonably realizes the contraction of the electron density of the cation due to the deficit of an electron.

A renormalization-group analysis of a spin-1 Ising ferromagnet with competing crystal-field and repulsive biquadratic interactions

International Nuclear Information System (INIS)

Snowman, Daniel P.

2009-01-01

Phase diagrams have been produced and critical exponents calculated for a Blume-Emery-Griffiths system with competing biquadratic and crystal-field interactions with uniform ferromagnetic bilinear interactions. This competition directly effects the clustering and density of nonmagnetic impurities. These results have been produced using renormalization-group methods with a hierarchical lattice. A series of planes of constant, repulsive biquadratic coupling have been probed while varying the temperature and concentration of annealed vacancies in the system. The sinks have been analyzed and interpreted, and critical exponents calculated for the higher order transitions.

Multicritical behavior of the antiferromagnetic Blume-Emery-Griffiths model with the repulsive biquadratic coupling in an external magnetic field

International Nuclear Information System (INIS)

Erdinc, Ahmet; Canko, Osman; Keskin, Mustafa

2006-01-01

We have studied the antiferromagnetic Blume-Emery-Griffiths model with the repulsive biquadratic coupling in an external magnetic field using the lowest approximation of the cluster variation method which is identical to the mean-field approximation. First, we have investigated the thermal variations of the sublattice magnetizations and obtained four different main topological types. Then, we have calculated the phase diagrams and five main different phase diagram topologies are found. Finally, the discussion and comparison of the phase diagrams are made

Multicritical behavior of the antiferromagnetic Blume-Emery-Griffiths model with the repulsive biquadratic coupling in an external magnetic field

Energy Technology Data Exchange (ETDEWEB)

Erdinc, Ahmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: keskin@erciyes.edu.tr

2006-06-15

We have studied the antiferromagnetic Blume-Emery-Griffiths model with the repulsive biquadratic coupling in an external magnetic field using the lowest approximation of the cluster variation method which is identical to the mean-field approximation. First, we have investigated the thermal variations of the sublattice magnetizations and obtained four different main topological types. Then, we have calculated the phase diagrams and five main different phase diagram topologies are found. Finally, the discussion and comparison of the phase diagrams are made.

Mean-field behavior in coupled oscillators with attractive and repulsive interactions.

Science.gov (United States)

Hong, Hyunsuk; Strogatz, Steven H

2012-05-01

We consider a variant of the Kuramoto model of coupled oscillators in which both attractive and repulsive pairwise interactions are allowed. The sign of the coupling is assumed to be a characteristic of a given oscillator. Specifically, some oscillators repel all the others, thus favoring an antiphase relationship with them. Other oscillators attract all the others, thus favoring an in-phase relationship. The Ott-Antonsen ansatz is used to derive the exact low-dimensional dynamics governing the system's long-term macroscopic behavior. The resulting analytical predictions agree with simulations of the full system. We explore the effects of changing various parameters, such as the width of the distribution of natural frequencies and the relative strengths and proportions of the positive and negative interactions. For the particular model studied here we find, unexpectedly, that the mixed interactions produce no new effects. The system exhibits conventional mean-field behavior and displays a second-order phase transition like that found in the original Kuramoto model. In contrast to our recent study of a different model with mixed interactions [Phys. Rev. Lett. 106, 054102 (2011)], the π state and traveling-wave state do not appear for the coupling type considered here.

Dynamics of unvisited sites in the presence of mutually repulsive random walkers

International Nuclear Information System (INIS)

Das, Pratap Kumar; Dasgupta, Subinay; Sen, Parongama

2007-01-01

We have considered the persistence of unvisited sites of a lattice, i.e., the probability S(t) that a site remains unvisited till time t in the presence of mutually repulsive random walkers in one dimension. The dynamics of this system has direct correspondence to that of the domain walls in a certain system of Ising spins where the number of domain walls becomes fixed following a zero-temperature quench. Here we get the result that S(t) ∼ exp(-αt β ) where β is close to 0.5 and α a function of the density of the walkers ρ. The fraction of persistent sites in the presence of independent walkers of density ρ' is known to be S'(t) = exp(-2√(2/π ρ't 1/2 ). We show that a mapping of the interacting walkers' problem to the independent walkers' problem is possible with ρ' = ρ/(1 - ρ) provided ρ' and ρ are small. We also discuss some other intricate results obtained in the interacting walkers' case

Fixed-Wing UAVs Flock Control through Cohesion and Repulsion Behaviours Combined with a Leadership

Directory of Open Access Journals (Sweden)

Cezary Kownacki

2016-02-01

Full Text Available The aim of this paper is to present a novel approach to swarm control of small fixed-wing UAVs, which combines only two flocking behaviours with a leadership feature. In the presented approach, two fundamental rules of Reynolds flocking are applied, i.e., cohesion and repulsion, as the base of a decentralized control of self-organization of the flock. These rules are combined with a leadership feature, which is responsible for a global behaviour of guidance, as in the case of animals. Such a bio-inspired combination allows the achievement of a coherent collective flight of a flock of fixed-wing UAVs without applying formal behaviours of migration and alignment. This highly simplifies an implementation of the algorithm. The presented results include both numerical simulations and experimental flights, which validate the hardware implementation of the approach.

Negative-mass mitigation of Coulomb repulsion for terahertz undulator radiation of electron bunches

Energy Technology Data Exchange (ETDEWEB)

Balal, N.; Magory, E. [Ariel University, Ariel 40700 (Israel); Bandurkin, I. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Bratman, V. L. [Ariel University, Ariel 40700 (Israel); Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, 46 Ulyanov St., Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University of Nizhny Novgorod, 23 Gagarin Avenue, Nizhny Novgorod 603950 (Russian Federation)

2015-10-19

It is proposed to utilize the effect of negative mass for stabilization of the effective axial size of very dense and short electron bunches produced by photo-injector guns by using combined undulator and strong uniform magnetic fields. It has been shown that in the “abnormal” regime, an increase in the electron energy leads to a decrease in the axial velocity of the electron; due to the negative-mass effect, the Coulomb repulsion of electrons leads to their attraction and formation of a fairly stable and compact bunch “nucleus.” An undulator with a strong uniform magnetic field providing the negative-mass effect is designed for an experimental source of terahertz radiation. The use of the negative-mass regime in this experiment should result in a long-pulse coherent spontaneous undulator emission from a short dense moderately relativistic (5.5 MeV) photo-injector electron bunch with a high (up to 20%) efficiency and a narrow frequency spectrum.

Various oscillation patterns in phase models with locally attractive and globally repulsive couplings.

Science.gov (United States)

Sato, Katsuhiko; Shima, Shin-ichiro

2015-10-01

We investigate a phase model that includes both locally attractive and globally repulsive coupling in one dimension. This model exhibits nontrivial spatiotemporal patterns that have not been observed in systems that contain only local or global coupling. Depending on the relative strengths of the local and global coupling and on the form of global coupling, the system can show a spatially uniform state (in-phase synchronization), a monotonically increasing state (traveling wave), and three types of oscillations of relative phase difference. One of the oscillations of relative phase difference has the characteristic of being locally unstable but globally attractive. That is, any small perturbation to the periodic orbit in phase space destroys its periodic motion, but after a long time the system returns to the original periodic orbit. This behavior is closely related to the emergence of saddle two-cluster states for global coupling only, which are connected to each other by attractive heteroclinic orbits. The mechanism of occurrence of this type of oscillation is discussed.

Fiscal transfers based on inputs or outcomes? Lessons from the Twelfth and Thirteenth Finance Commission in India.

Science.gov (United States)

Fan, Victoria Y; Iyer, Smriti; Kapur, Avani; Mahbub, Rifaiyat; Mukherjee, Anit

2018-01-01

There is limited empirical evidence about the efficacy of fiscal transfers for a specific purpose, including for health which represents an important source of funds for the delivery of public services especially in large populous countries such as India. To examine two distinct methodologies for allocating specific-purpose centre-to-state transfers, one using an input-based formula focused on equity and the other using an outcome-based formula focused on performance. We examine the Twelfth Finance Commission (12FC)'s use of Equalization Grants for Health (EGH) as an input-based formula and the Thirteenth Finance Commission (13FC)'s use of Incentive Grants for Health (IGH) as an outcome-based formula. We simulate and replicate the allocation of these two transfer methodologies and examine the consequences of these fiscal transfer mechanisms. The EGH placed conditions for releasing funds, but states varied in their ability to meet those conditions, and hence their allocations varied, eg, Madhya Pradesh received 100% and Odisha 67% of its expected allocation. Due to the design of the IGH formula, IGH allocations were unequally distributed and highly concentrated in 4 states (Manipur, Sikkim, Tamil Nadu, Nagaland), which received over half the national IGH allocation. The EGH had limited impact in achieving equalization, whereas the IGH rewards were concentrated in states which were already doing better. Greater transparency and accountability of centre-to-state allocations and specifically their methodologies are needed to ensure that allocation objectives are aligned to performance. © 2017 The Authors. The International Journal of Health Planning and Management published by John Wiley & Sons Ltd.

Quantum mechanics study of repulsive π-π interaction and flexibility of phenyl moiety in the iron azodioxide complex

Science.gov (United States)

Liu, Yuemin; Liu, Yucheng; Murru, Siva; Tzeng, Nianfeng; Srivastava, Radhey S.

2015-10-01

In this study, repulsive π-π interactions within iron azodioxide complex Fe[Ph(O)NN(O)Ph]3 were quantum mechanically characterized using DFT, MP2 and CCSD(T) methods. Flexibility of six phenyl moieties in this complex structure was also investigated by structural optimization approach using the DFT methods. Our MP2 and CCSD(T) calculations of the closest pair provided interaction energy of 6.62 and 8.29 kcal/mol respectively, which indicate a strongest repulsion among these intra-molecular π-π interactions. Interaction energy of the particular π-π pair calculated from 24 hybrid DFT methods ranges from 4.56 kcal/mol from BHandH method to 15.15 kcal/mol from O3LYP method. Cares should be exercised when interpreting interaction energy and geometry optimization from DFT simulation of systems containing π-π interaction. Comparison between the DFT results and the benchmark CCSD(T) results shows that the DFT calculations of π-π interaction are reasonable but still need to be interpreted with caution. Furthermore, MP2 interaction energy of -44.69 kcal/mol between two substituted π systems/phenyl rings Ph(O)N-moieties suggested that above energetically unfavorable π-π interaction can be compensated by the covalent bond N-N in a single ligand Ph(O)NN(O)Ph, which allows for a reasonable stability across the complex molecules. Optimizations of the entire complex molecule using B3LYP and M06HF methods produced a large variation of π-π distances and orientations, which implied that the complex molecule may perform catalysis at room temperature.

Radio Frequency Power in Plasmas: 12th Topical Conference. Proceedings

International Nuclear Information System (INIS)

Ryan, P.M.; Intrator, T.

1997-01-01

The twelfth Topical Conference on Radio Frequency Power in Plasmas was held in April, 1997, in Georgia, USA under the sponsorship of Oak Ridge National Laboratory of the US Department of Energy, the University of Wisconsin, and the American Physical Society. A large part of the conference was devoted to the ion cyclotron range of frequencies. Radio frequency contributions to the creation and maintenance of transport barriers to both particle and heat flux received a lot of attention. In addition to plasma heating, the use of RF as a versatile tool to drive current, shape profiles and stabilize plasmas was also discussed. The RF systems designs for ITER, ICRF heating advances on helical devices were among the topics of interest, so were progress in ion cyclotron codes, advanced launchers and technology, RF startup, general wave theory and the application of RF plasmas to material processing. A total of 103 papers were presented and are included in these proceedings. Out of these, 54 have been abstracted for the Energy Science and Technology database

Condensed phase QM/MM simulations utilizing the exchange core functions to describe exchange repulsions at the QM boundary region

Energy Technology Data Exchange (ETDEWEB)

Umino, Satoru; Takahashi, Hideaki, E-mail: hideaki@m.tohoku.ac.jp; Morita, Akihiro [Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Miyagi 980-8578 (Japan)

2016-08-28

In a recent work, we developed a method [H. Takahashi et al., J. Chem. Phys. 143, 084104 (2015)] referred to as exchange-core function (ECF) approach, to compute exchange repulsion E{sub ex} between solute and solvent in the framework of the quantum mechanical (QM)/molecular mechanical (MM) method. The ECF, represented with a Slater function, plays an essential role in determining E{sub ex} on the basis of the overlap model. In the work of Takahashi et al. [J. Chem. Phys. 143, 084104 (2015)], it was demonstrated that our approach is successful in computing the hydrogen bond energies of minimal QM/MM systems including a cationic QM solute. We provide in this paper the extension of the ECF approach to the free energy calculation in condensed phase QM/MM systems by combining the ECF and the QM/MM-ER approach [H. Takahashi et al., J. Chem. Phys. 121, 3989 (2004)]. By virtue of the theory of solutions in energy representation, the free energy contribution δμ{sub ex} from the exchange repulsion was naturally formulated. We found that the ECF approach in combination with QM/MM-ER gives a substantial improvement on the calculation of the hydration free energy of a hydronium ion. This can be attributed to the fact that the ECF reasonably realizes the contraction of the electron density of the cation due to the deficit of an electron.

Techno-economic assessment and policy of gas power generation considering the role of multiple stakeholders in China

International Nuclear Information System (INIS)

Dong Jun; Zhang Xu; Xu Xiaolin

2012-01-01

In accordance with the energy planning in China, within the “Twelfth Five-Year” period (2011–2015), the proportion of natural gas among primary energy consumption is expected to increase from the current 4% to 8%. In 2015, about 17 natural gas pipelines will be completed. This paper reviews the current situation of gas power generation, analyzes the main opportunities and obstacles of gas power generation development in China, and conducts a techno-economic assessment of the natural gas power generation, taking into account the role and the interaction of the multiple stakeholders in the natural gas industry chain. Taking a power plant fueled with the natural gas transported by the second West-to-East Pipeline as an example, it is found that the on-grid power price fluctuates upward with the rise of gas price and downward with the increase of annual utilization hours, and the influences of tax policies on the on-grid power price prove to be highly significant. As the analysis and calculation indicate, the environmental benefits of natural gas power generation ought to be strongly emphasized, compared with coal-fired power generation. Finally, this paper puts forward specific policy recommendations, from the perspectives of electricity price, gas price, tax, power grid dispatching, etc. - Highlights: ► Presents the opportunities and obstacles of gas power generation development in China. ► Analyzes the interactions of multiple stakeholders in the natural gas industry chain. ► Conducts a techno-economic assessment on the natural gas power generation. ► Discusses the responsibilities and risks of multiple stakeholders. ► Puts forward policy recommendations, from electricity price, gas price, tax, etc.

Case Studies in Policy Making. Twelfth Edition

Science.gov (United States)

2010-01-01

1185.html. 44. Howard La Franchi , “US Seeks Global Aid for Iraq,” Christian Science Monitor, 21 Jan- uary 2004, 1. 45. Phillips, Losing Iraq, 180. 46...military actions. International trends, such as conflicting norms, globalization , and emerging technology, also play a critical role. The domestic...polarity, or distribution of power within the IPS, whether or not a particular actor possessed weapons of mass destruction, a global dependency on oil

Dragon (repulsive guidance molecule b) inhibits IL-6 expression in macrophages.

Science.gov (United States)

Xia, Yin; Cortez-Retamozo, Virna; Niederkofler, Vera; Salie, Rishard; Chen, Shanzhuo; Samad, Tarek A; Hong, Charles C; Arber, Silvia; Vyas, Jatin M; Weissleder, Ralph; Pittet, Mikael J; Lin, Herbert Y

2011-02-01

Repulsive guidance molecule (RGM) family members RGMa, RGMb/Dragon, and RGMc/hemojuvelin were found recently to act as bone morphogenetic protein (BMP) coreceptors that enhance BMP signaling activity. Although our previous studies have shown that hemojuvelin regulates hepcidin expression and iron metabolism through the BMP pathway, the role of the BMP signaling mediated by Dragon remains largely unknown. We have shown previously that Dragon is expressed in neural cells, germ cells, and renal epithelial cells. In this study, we demonstrate that Dragon is highly expressed in macrophages. Studies with RAW264.7 and J774 macrophage cell lines reveal that Dragon negatively regulates IL-6 expression in a BMP ligand-dependent manner via the p38 MAPK and Erk1/2 pathways but not the Smad1/5/8 pathway. We also generated Dragon knockout mice and found that IL-6 is upregulated in macrophages and dendritic cells derived from whole lung tissue of these mice compared with that in respective cells derived from wild-type littermates. These results indicate that Dragon is an important negative regulator of IL-6 expression in immune cells and that Dragon-deficient mice may be a useful model for studying immune and inflammatory disorders.

Highly excited bound-state resonances of short-range inverse power-law potentials

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Academic College, Jerusalem (Israel)

2017-11-15

We study analytically the radial Schroedinger equation with long-range attractive potentials whose asymptotic behaviors are dominated by inverse power-law tails of the form V(r) = -β{sub n}r{sup -n} with n > 2. In particular, assuming that the effective radial potential is characterized by a short-range infinitely repulsive core of radius R, we derive a compact analytical formula for the threshold energy E{sub l}{sup max} = E{sub l}{sup max}(n, β{sub n}, R), which characterizes the most weakly bound-state resonance (the most excited energy level) of the quantum system. (orig.)

Structure factor of polymers interacting via a short range repulsive potential: Application to hairy wormlike micelles

International Nuclear Information System (INIS)

Massiera, Gladys; Ramos, Laurence; Ligoure, Christian; Pitard, Estelle

2003-01-01

We use the random phase approximation to compute the structure factor S(q) of a solution of chains interacting through a soft and short range repulsive potential V. Above a threshold polymer concentration, whose magnitude is essentially controlled by the range of the potential, S(q) exhibits a peak whose position depends on the concentration. We take advantage of the close analogy between polymers and wormlike micelles and apply our model, using a Gaussian function for V, to quantitatively analyze experimental small angle neutron scattering profiles of solutions of hairy wormlike micelles. These samples, which consist in surfactant self-assembled flexible cylinders decorated by amphiphilic copolymer, provide indeed an appropriate experimental model system to study the structure of sterically interacting polymer solutions

Acidic pH retards the fibrillization of human islet amyloid polypeptide due to electrostatic repulsion of histidines

Science.gov (United States)

Li, Yang; Xu, Weixin; Mu, Yuguang; Zhang, John Z. H.

2013-08-01

The human Islet Amyloid Polypeptide (hIAPP) is the major constituent of amyloid deposits in pancreatic islets of type-II diabetes. IAPP is secreted together with insulin from the acidic secretory granules at a low pH of approximately 5.5 to the extracellular environment at a neutral pH. The increased accumulation of extracellular hIAPP in diabetes indicates that changes in pH may promote amyloid formation. To gain insights and underlying mechanisms of the pH effect on hIAPP fibrillogenesis, all-atom molecular dynamics simulations in explicit solvent model were performed to study the structural properties of five hIAPP protofibrillar oligomers, under acidic and neutral pH, respectively. In consistent with experimental findings, simulation results show that acidic pH is not conducive to the structural stability of these oligomers. This provides a direct evidence for a recent experiment [L. Khemtemourian, E. Domenech, J. P. F. Doux, M. C. Koorengevel, and J. A. Killian, J. Am. Chem. Soc. 133, 15598 (2011)], 10.1021/ja205007j, which suggests that acidic pH inhibits the fibril formation of hIAPP. In addition, a complementary coarse-grained simulation shows the repulsive electrostatic interactions among charged His18 residues slow down the dimerization process of hIAPP by twofold. Besides, our all-atom simulations reveal acidic pH mainly affects the local structure around residue His18 by destroying the surrounding hydrogen-bonding network, due to the repulsive interactions between protonated interchain His18 residues at acidic pH. It is also disclosed that the local interactions nearby His18 operating between adjacent β-strands trigger the structural transition, which gives hints to the experimental findings that the rate of hIAPP fibril formation and the morphologies of the fibrillar structures are strongly pH-dependent.

Harmonically trapped attractive and repulsive spin–orbit and Rabi coupled Bose–Einstein condensates

International Nuclear Information System (INIS)

Chiquillo, Emerson

2017-01-01

Numerically we investigate the ground state of effective one-dimensional spin–orbit (SO) and Rabi coupled two pseudo-spinor Bose–Einstein condensates (BECs) under the effect of harmonic traps. For both signs of the interaction, density profiles of SO and Rabi coupled BECs in harmonic potentials, which simulate a real experimental situation are obtained. The harmonic trap causes a strong reduction of the multi-peak nature of the condensate and it increases its density. For repulsive interactions, the increase of SO coupling results in an uncompressed less dense condensate and with increased multi-peak nature of the density. The increase of Rabi coupling leads to a density increase with an almost constant number of multi-peaks. For both signs of the interaction and negative values of Rabi coupling, the condensate develops a notch in the central point and it seems to a dark-in-bright soliton. In the case of the attractive nonlinearity, an interesting result is the increase of the collapse threshold under the action of the SO and Rabi couplings. (paper)

Repulsive baryonic interactions and lattice QCD observables at imaginary chemical potential

Directory of Open Access Journals (Sweden)

Volodymyr Vovchenko

2017-12-01

Full Text Available The first principle lattice QCD methods allow to calculate the thermodynamic observables at finite temperature and imaginary chemical potential. These can be compared to the predictions of various phenomenological models. We argue that Fourier coefficients with respect to imaginary baryochemical potential are sensitive to modeling of baryonic interactions. As a first application of this sensitivity, we consider the hadron resonance gas (HRG model with repulsive baryonic interactions, which are modeled by means of the excluded volume correction. The Fourier coefficients of the imaginary part of the net-baryon density at imaginary baryochemical potential – corresponding to the fugacity or virial expansion at real chemical potential – are calculated within this model, and compared with the Nt=12 lattice data. The lattice QCD behavior of the first four Fourier coefficients up to T≃185 MeV is described fairly well by an interacting HRG with a single baryon–baryon eigenvolume interaction parameter b≃1 fm3, while the available lattice data on the difference χ2B−χ4B of baryon number susceptibilities is reproduced up to T≃175 MeV. Keywords: Hadron resonance gas, Excluded volume, Imaginary chemical potential

Two-dimensional assemblies of soft repulsive colloids confined at fluid interfaces

Science.gov (United States)

Isa, L.; Buttinoni, I.; Fernandez-Rodriguez, M. A.; Vasudevan, S. A.

2017-07-01

Colloidal systems are an excellent example of a materials class for which interrogating fundamental questions leads to answers of direct applied relevance. In our group, we in particular focus on two-dimensional assemblies of micro- and nano-particles confined at the interface between two fluids, e.g., oil-water. Here, we review our work on systems interacting through soft repulsive forces of different origin, i.e., electrostatic and steric. By starting from the paradigmatic case of charged colloids at an interface, we show how they are both offering great opportunities as model systems to investigate the structural and mechanical response of materials and as versatile patterning tools for surface nanostructuring. We then move to the case of deformable particles interacting via steric contacts. We first examine microgel particles, which we also demonstrate as very promising models for structural investigations and robust elements for tunable nanolithography. We conclude by briefly discussing the case of particles comprising a hard inorganic core and a deformable polymer shell, which maintain some of the advantageous features of microgel particles, but also enable the realization of two-dimensional functional materials. This article offers our perspective on a very active field of research, where many interesting developments are expected in the near future. Contribution to the Focus Issue Self-assemblies of Inorganic and Organic Nanomaterials edited by Marie-Paule Pileni.

Synchronization of coupled active rotators by common noise

Science.gov (United States)

Dolmatova, Anastasiya V.; Goldobin, Denis S.; Pikovsky, Arkady

2017-12-01

We study the effect of common noise on coupled active rotators. While such a noise always facilitates synchrony, coupling may be attractive (synchronizing) or repulsive (desynchronizing). We develop an analytical approach based on a transformation to approximate angle-action variables and averaging over fast rotations. For identical rotators, we describe a transition from full to partial synchrony at a critical value of repulsive coupling. For nonidentical rotators, the most nontrivial effect occurs at moderate repulsive coupling, where a juxtaposition of phase locking with frequency repulsion (anti-entrainment) is observed. We show that the frequency repulsion obeys a nontrivial power law.

Aristocracia y monarquía en los reinos de Castilla y León: el caso de la familia Lara

Directory of Open Access Journals (Sweden)

Simon Doubleday

2001-12-01

Full Text Available Between the twelfth century and the fourteenth, there was a fundamental change in the basis of the Lara family s power. At the outset, their influence derived primarily from personal access to, and control over, the monarch; throughout the twelfth century, the family s wealth rested heavily on possession of the royal offices known as tenencias, which were the principal fruit of courtly influence. But from the middle of the thirteenth century, the aftershocks of the reconquests of Seville and Córdoba, and the expansion of royal administration, meant that symbiosis was increasingly supplanted by a confrontational political climate marked by an acceleration of patrimonial accumulation by aristocratic lineages such as the Laras. The new structure of aristocratic power would long outlast the Lara family itself, surviving well into the modem age and finding expression in a culture in which, more than in any other western European society, the authority and values of nobility were dominant.

Dragon (repulsive guidance molecule b, RGMb) is a novel gene that promotes colorectal cancer growth.

Science.gov (United States)

Shi, Ying; Chen, Guo-Bin; Huang, Xiao-Xiao; Xiao, Chuan-Xing; Wang, Huan-Huan; Li, Ye-Sen; Zhang, Jin-Fang; Li, Shao; Xia, Yin; Ren, Jian-Lin; Guleng, Bayasi

2015-08-21

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers and a major cause of cancer death. However, the molecular mechanisms underlying CRC initiation, growth and metastasis are poorly understood. Dragon (RGMb), a member of the repulsive guidance molecule (RGM) family, has been recently identified as a co-receptor for bone morphogenetic protein (BMP) signaling, but the role of Dragon in CRC development is undefined. Here, we show that Dragon expression was increased in colon cancer tissues compared to control tissues in CAC mouse model and in human patients. Dragon promoted proliferation of CT26.WT and CMT93 colon cancer cells and accelerated tumor growth in the xenograft mouse model. Dragon's action on colon cancer development was mediated via the BMP4-Smad1/5/8 and Erk1/2 pathways. Therefore, our results have revealed that Dragon is a novel gene that promotes CRC growth through the BMP pathway. Dragon may be exploited as a potential therapeutic target for CRC treatment.

The quark model and the nature of the repulsive core of the nucleon-nucleon interaction

International Nuclear Information System (INIS)

Faessler, A.; Fernandez, F.; Luebeck, G.; Shimizu, K.

1982-01-01

The nature of the repulsive core of the nucleon-nucleon is studied in the quark model. The resonating group equation for nucleon-nucleon scattering is solved with the colour Fermi-Breit interaction including further a linear or quadratic confinement potential. It is shown that the colour magnetic interaction which is adjusted to the Δ-nucleon mass splitting favours the orbital symmetry and disfavours the completely symmetric orbital state. For the important orbital symmetry the relative S wave function between the two nucleons has to have a node. In the framework of the resonating group including the NN, ΔΔ and the hidden colour (CC) channels it is shown that this node produces a 3 S and 1 S phase shift which is identical to a hard core phase shift with a hard core radius γ 0 between 0.3 and 0.6 fm depending on the assumed root mean square radius of the quark part of the nucleon. (orig./HSI)

Magnetism of one-dimensional strongly repulsive spin-1 bosons with antiferromagnetic spin-exchange interaction

International Nuclear Information System (INIS)

Lee, J. Y.; Guan, X. W.; Batchelor, M. T.; Lee, C.

2009-01-01

We investigate magnetism and quantum phase transitions in a one-dimensional system of integrable spin-1 bosons with strongly repulsive density-density interaction and antiferromagnetic spin-exchange interaction via the thermodynamic Bethe ansatz method. At zero temperature, the system exhibits three quantum phases: (i) a singlet phase of boson pairs when the external magnetic field H is less than the lower critical field H c1 ; (ii) a ferromagnetic phase of atoms in the hyperfine state |F=1, m F =1> when the external magnetic field exceeds the upper critical field H c2 ; and (iii) a mixed phase of singlet pairs and unpaired atoms in the intermediate region H c1 c2 . At finite temperatures, the spin fluctuations affect the thermodynamics of the model through coupling the spin bound states to the dressed energy for the unpaired m F =1 bosons. However, such spin dynamics is suppressed by a sufficiently strong external field at low temperatures. Thus the singlet pairs and unpaired bosons may form a two-component Luttinger liquid in the strong coupling regime.

Blow-up behavior of ground states for a nonlinear Schrödinger system with attractive and repulsive interactions

Science.gov (United States)

Guo, Yujin; Zeng, Xiaoyu; Zhou, Huan-Song

2018-01-01

We consider a nonlinear Schrödinger system arising in a two-component Bose-Einstein condensate (BEC) with attractive intraspecies interactions and repulsive interspecies interactions in R2. We get ground states of this system by solving a constrained minimization problem. For some kinds of trapping potentials, we prove that the minimization problem has a minimizer if and only if the attractive interaction strength ai (i = 1 , 2) of each component of the BEC system is strictly less than a threshold a*. Furthermore, as (a1 ,a2) ↗ (a* ,a*), the asymptotical behavior for the minimizers of the minimization problem is discussed. Our results show that each component of the BEC system concentrates at a global minimum of the associated trapping potential.

Size-dependent social attraction and repulsion explains the decision of Atlantic cod Gadus morhua to enter baited pots.

Science.gov (United States)

Anders, N; Fernö, A; Humborstad, O-B; Løkkeborg, S; Rieucau, G; Utne-Palm, A C

2017-12-01

The present study tested whether the presence of already retained fishes inside baited fish pots acted as a social attraction and affected the entrance probability of Atlantic cod Gadus morhua in a fjord in northern Norway. Video analysis revealed that the probability of an entrance initially increased with the presence of low numbers of fishes inside the pot, but subsequently decreased at a critical number of caught fishes. The critical number was dependent on the size of the G. morhua attempting to enter. This demonstrates that social attraction and repulsion play a role in G. morhua pot fishing and has important implications for the capture efficiency of fisheries executed with pots. © 2017 The Fisheries Society of the British Isles.

Occupational radiation exposure. Twelfth annual report, 1979

International Nuclear Information System (INIS)

Brooks, B.; McDonald, S.; Richardson, E.

1982-08-01

This report summarizes the occupational exposure data that is maintained in the US Nuclear Regulatory Commission's Radiation Exposure Information and Reports System (REIRS). This report is usually published on an annual basis and is available at all NRC public document rooms. The bulk of the information contained in the report was extracted from annual statistical reports submitted by all NRC licensees subject to the reporting requirements of 10 CFR 20.407. Four categories of licensees - operating nuclear power reactors, fuel fabricators and reprocessors, industrial radiographers, and manufacturers and distributors of specified quantities of byproduct materials - also submit personal identification and exposure information for terminating employees pursuant to 10 CFR 20.408, and some analysis of this data is also presented in this report

The bacterial defensin resistance protein MprF consists of separable domains for lipid lysinylation and antimicrobial peptide repulsion.

Directory of Open Access Journals (Sweden)

Christoph M Ernst

2009-11-01

Full Text Available Many bacterial pathogens achieve resistance to defensin-like cationic antimicrobial peptides (CAMPs by the multiple peptide resistance factor (MprF protein. MprF plays a crucial role in Staphylococcus aureus virulence and it is involved in resistance to the CAMP-like antibiotic daptomycin. MprF is a large membrane protein that modifies the anionic phospholipid phosphatidylglycerol with l-lysine, thereby diminishing the bacterial affinity for CAMPs. Its widespread occurrence recommends MprF as a target for novel antimicrobials, although the mode of action of MprF has remained incompletely understood. We demonstrate that the hydrophilic C-terminal domain and six of the fourteen proposed trans-membrane segments of MprF are sufficient for full-level lysyl-phosphatidylglycerol (Lys-PG production and that several conserved amino acid positions in MprF are indispensable for Lys-PG production. Notably, Lys-PG production did not lead to efficient CAMP resistance and most of the Lys-PG remained in the inner leaflet of the cytoplasmic membrane when the large N-terminal hydrophobic domain of MprF was absent, indicating a crucial role of this protein part. The N-terminal domain alone did not confer CAMP resistance or repulsion of the cationic test protein cytochrome c. However, when the N-terminal domain was coexpressed with the Lys-PG synthase domain either in one protein or as two separate proteins, full-level CAMP resistance was achieved. Moreover, only coexpression of the two domains led to efficient Lys-PG translocation to the outer leaflet of the membrane and to full-level cytochrome c repulsion, indicating that the N-terminal domain facilitates the flipping of Lys-PG. Thus, MprF represents a new class of lipid-biosynthetic enzymes with two separable functional domains that synthesize Lys-PG and facilitate Lys-PG translocation. Our study unravels crucial details on the molecular basis of an important bacterial immune evasion mechanism and it may help

The Weight of Evidence Does Not Support the Listing of Styrene as “Reasonably Anticipated to be a Human Carcinogen” in NTP's Twelfth Report on Carcinogens

Science.gov (United States)

Rhomberg, Lorenz R.; Goodman, Julie E.; Prueitt, Robyn L.

2013-01-01

Styrene was listed as “reasonably anticipated to be a human carcinogen” in the twelfth edition of the National Toxicology Program's Report on Carcinogens based on what we contend are erroneous findings of limited evidence of carcinogenicity in humans, sufficient evidence of carcinogenicity in experimental animals, and supporting mechanistic data. The epidemiology studies show no consistent increased incidence of, or mortality from, any type of cancer. In animal studies, increased incidence rates of mostly benign tumors have been observed only in certain strains of one species (mice) and at one tissue site (lung). The lack of concordance of tumor incidence and tumor type among animals (even within the same species) and humans indicates that there has been no particular cancer consistently observed among all available studies. The only plausible mechanism for styrene-induced carcinogenesis—a non-genotoxic mode of action that is specific to the mouse lung—is not relevant to humans. As a whole, the evidence does not support the characterization of styrene as “reasonably anticipated to be a human carcinogen,” and styrene should not be listed in the Report on Carcinogens. PMID:23335843

Structure and dynamics of soft repulsive colloidal suspensions in the vicinity of the glass transition.

Science.gov (United States)

Crassous, Jérôme J; Casal-Dujat, Lucia; Medebach, Martin; Obiols-Rabasa, Marc; Vincent, Romaric; Reinhold, Frank; Boyko, Volodymyr; Willerich, Immanuel; Menzel, Andreas; Moitzi, Christian; Reck, Bernd; Schurtenberger, Peter

2013-08-20

We use a combination of different scattering techniques and rheology to highlight the link between structure and dynamics of dense aqueous suspensions of soft repulsive colloids in the vicinity of a glass transition. Three different latex formulations with an increasing amount of the hydrophilic component resulting in either purely electrostatically or electrosterically stabilized suspensions are investigated. From the analysis of the static structure factor measured by small-angle X-ray scattering, we derive an effective volume fraction that includes contributions from interparticle interactions. We further investigate the dynamics of the suspensions using 3D cross-correlation dynamic light scattering (3DDLS) and rheology. We analyze the data using an effective hard sphere model and in particular compare the linear viscoelasticity and flow behavior to the predictions of mode coupling theory, which accounts for a purely kinetic glass transition determined by the equilibrium structure factor. We demonstrate that seemingly very different colloidal systems exhibit the same generic behavior when the effects from interparticle interactions are incorporated using an effective volume fraction description.

Superconductor to spin-density-wave transition in quasi-one-dimensional metals with repulsive anisotropic interaction

International Nuclear Information System (INIS)

Rozhkov, A.V.

2007-01-01

A mechanism for superconductivity in a quasi-one-dimensional system with repulsive Ising-anisotropic interaction is studied. The Ising anisotropy opens the gap Δ s in the spin sector of the model. This gap allows the triplet superconductivity and the spin-density wave as the only broken symmetry phases. These phases are separated by the first order transition. The transport properties of the system are investigated in different parts of the phase diagram. The calculation of DC conductivity σ(T) in the high-temperature phase shows that the function σ(T) cannot be used as an indicator of a superconducting ground state: even if σ(T) is a decreasing function at high temperature, yet, the ground state may be insulating spin-density wave; the opposite is also true. The calculation of the spin dynamical structure factor S zz (q, ω) demonstrates that it is affected by the superconducting phase transition in a qualitative fashion: below T c the structure factor develops a gap with a coherent excitation inside this gap

Defining the contributions of permanent electrostatics, Pauli repulsion, and dispersion in density functional theory calculations of intermolecular interaction energies

Energy Technology Data Exchange (ETDEWEB)

Horn, Paul R., E-mail: prhorn@berkeley.edu; Mao, Yuezhi; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division Lawrence Berkeley National Laboratory Berkeley, California 94720 (United States)

2016-03-21

In energy decomposition analysis of Kohn-Sham density functional theory calculations, the so-called frozen (or pre-polarization) interaction energy contains contributions from permanent electrostatics, dispersion, and Pauli repulsion. The standard classical approach to separate them suffers from several well-known limitations. We introduce an alternative scheme that employs valid antisymmetric electronic wavefunctions throughout and is based on the identification of individual fragment contributions to the initial supersystem wavefunction as determined by an energetic optimality criterion. The density deformations identified with individual fragments upon formation of the initial supersystem wavefunction are analyzed along with the distance dependence of the new and classical terms for test cases that include the neon dimer, ammonia borane, water-Na{sup +}, water-Cl{sup −}, and the naphthalene dimer.

Report on the results of the twelfth medical examination of atomic bomb survivors residing in North America

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Yasuji [Hiroshima Prefectural Medical Association (Japan); Ohama, Koso; Fujiwara, Saeko (and others)

2000-06-01

The twelfth medical examination of atomic bomb survivors residing in North America, was conducted in San Francisco and Seattle from May 20 through June 2 1999, and in Los Angeles and Hawaii from June 9 through 23 1999, The examination included an interview, measurement of height, weight, and blood pressure, an ECG, urine and stool tests, blood tests, a physical examination, examination of the breast, thyroid, and rectum by a surgeon, and screening for uterine cancer and a gynecological interview and examination by an obstetrician and gynecologist. The total confirmed number of A-bomb survivors residing in North America as of the end of June 1999 was 1076. Of the 1062 survivors that remained after excluding the 14 subjects whose survey was incomplete, 279 males and 654 females had been exposed in Hiroshima, and 10 males and 119 females in Nagasaki. The peak age at the time of exposure in both sexes was 15-19 years, followed by 10-14 years. The number of survivors exposed <2000 m from the hypocenter was 236, accounting for 21.9% of the total. The confirmed number of survivors exposed in utero was 26. The survivors' age (mean {+-}S.D.) was: 69.0{+-}8.69 years; males, 68.4{+-}80.5 years; females, 69.2{+-}8.91 years. A total of 414 survivors were examined (male 129; female 285; mean age 68.0 years). Approximately 80% of the examinees had experienced at least one general symptom. Many still complain of symptoms that suggest possible posttraumatic stress disorder as a result of exposure to the A-bomb. It will be necessary to consider providing mental health care by psychiatrists beginning with the next examination. The prevalence of life-style diseases has been gradually increased with age. A previous history of cancer was found in 9.2% of the examinees. The most prevalent was of breast cancer, followed by malignant tumors of the colon, rectum, uterus, brain, stomach, and thyroid. The need for cancer screening and promotion of life-style education was keenly felt. (K.H.)

Stability of the Superconducting d-Wave Pairing Toward the Intersite Coulomb Repulsion in CuO_2 Plane

Science.gov (United States)

Val'kov, V. V.; Dzebisashvili, D. M.; Korovushkin, M. M.; Barabanov, A. F.

2018-06-01

Taking into account the real crystalline structure of the CuO_2 plane and the strong spin-fermion coupling, we study the influence of the intersite Coulomb repulsion between holes on the Cooper instability of the spin-polaron quasiparticles in cuprate superconductors. The analysis shows that only the superconducting d-wave pairing is implemented in the whole region of doping, whereas the solutions of the self-consistent equations for the s-wave pairing are absent. It is shown that intersite Coulomb interaction V_1 between the holes located at the nearest oxygen ions does not affect the d-wave pairing, because its Fourier transform V_q vanishes in the kernel of the corresponding integral equation. The intersite Coulomb interaction V_2 of quasiparticles located at the next-nearest oxygen ions does not vanish in the integral equations, however, but it is also shown that the d-wave pairing is robust toward this interaction for physically reasonable values of V_2.

Repulsive energy and the Grueneisen parameter of alkali halides calculated on the basis of a quantum-statistical ab initio theory

International Nuclear Information System (INIS)

Kucharczyk, M.; Olszewski, S.

1982-01-01

The Grueneisen parameter of alkali halides is calculated by an ab initio quantum-statistical method and then compared with the experimental data. The crystal model applied assumes the crystal ions to be compressible but impenetrable spheres. The ions are described with the aid of a modified Thomas-Fermi theory with exchange. At the next step it is possible to calculate the energy needed to transform the system of the non-interacting ions into the ionic system represented by the crystal lattice. This calculation allows for an ab initio estimate of the parameters entering the Born, or the Born-Mayer, repulsive part of the crystal energy. The parameters are then used in the calculation of the Grueneisen parameter and its dependence on the crystal compression. (author)

Repulsive guidance molecule a blockade exerts the immunoregulatory function in DCs stimulated with ABP and LPS.

Science.gov (United States)

Xu, Xuxu; Gao, Yan; Zhai, Zhiyong; Zhang, Shuo; Shan, Fengping; Feng, Juan

2016-08-02

Repulsive guidance molecule a (RGMa) is an axonal guidance molecule that has recently found to exert function in immune system. This study evaluated the function of RGMa in modulation of dendritic cells (DCs) function stimulated with Achyranthes bidentata polysaccharide (ABP) and lipopolysaccharide (LPS) using a RGMa-neutralizing antibody. Compared with the Control-IgG/ABP and Control-IgG/LPS groups, DCs in the Anti-RGMa/ABP and Anti-RGMa/LPS groups 1) showed small, round cells with a few cell processes and organelles, and many pinocytotic vesicles; 2) had decreased MHC II, CD86, CD80, and CD40 expression; 3) displayed the decreased IL-12p70, IL-1β and TNF-α levels and increased IL-10 secretion; 4) had a high percentage of FITC-dextran uptake; and 5) displayed a reduced ability to drive T cell proliferation and reinforced T cell polarization toward a Th2 cytokine pattern. We conclude that DCs treated with RGMa-neutralizing antibodies present with tolerogenic and immunoregulatory characteristics, which provides new insights into further understanding of the function of RGMa.

Projection of the six-quark wave function onto the NN channel and the problem of the repulsive core in the NN interaction

International Nuclear Information System (INIS)

Kusainov, A.M.; Neudatchin, V.G.; Obukhovsky, I.T.

1991-01-01

A modification of the resonating-group method (RGM) is proposed which includes the multiquark shell-model configurations in the nucleon overlap region. The instanton, gluon, and π,σ exchange is taken into account, the interaction constants being consistent with the baryon spectrum. This enables one to cover a wide interval of NN scattering energies up to E lab =2 GeV. The projection of the six-quark wave function onto the NN and other baryon channels is discussed in detail in our approach and in other RGM versions as well, and in this context the problem of repulsive core in the NN forces is discussed

Salt-Dependent DNA-DNA Spacings in Intact Bacteriophage lambda Reflect Relative Importance of DNA Self-Repulsion and Bending Energies

Energy Technology Data Exchange (ETDEWEB)

X Qiu; D Rau; V Parsegian; L Fang; C Knobler; W Gelbart

2011-12-31

Using solution synchrotron x-ray scattering, we measure the variation of DNA-DNA d spacings in bacteriophage {lambda} with mono-, di-, and polyvalent salt concentrations, for wild-type [48.5 x 10{sup 3} base pairs (bp)] and short-genome-mutant (37.8 kbp) strains. From the decrease in d spacings with increasing salt, we deduce the relative contributions of DNA self-repulsion and bending to the energetics of packaged phage genomes. We quantify the DNA-DNA interaction energies within the intact phage by combining the measured d spacings in the capsid with measurements of osmotic pressure in DNA assemblies under the same salt conditions in bulk solution. In the commonly used Tris-Mg buffer, the DNA-DNA interaction energies inside the phage capsids are shown to be about 1 kT/bp, an order of magnitude larger than the bending energies.

Investigation of attractive and repulsive interactions associated with ketones in supercritical CO2, based on Raman spectroscopy and theoretical calculations.

Science.gov (United States)

Kajiya, Daisuke; Saitow, Ken-ichi

2013-08-07

Carbonyl compounds are solutes that are highly soluble in supercritical CO2 (scCO2). Their solubility governs the efficiency of chemical reactions, and is significantly increased by changing a chromophore. To effectively use scCO2 as solvent, it is crucial to understand the high solubility of carbonyl compounds, the solvation structure, and the solute-solvent intermolecular interactions. We report Raman spectroscopic data, for three prototypical ketones dissolved in scCO2, and four theoretical analyses. The vibrational Raman spectra of the C=O stretching modes of ketones (acetone, acetophenone, and benzophenone) were measured in scCO2 along the reduced temperature Tr = T∕Tc = 1.02 isotherm as a function of the reduced density ρr = ρ∕ρc in the range 0.05-1.5. The peak frequencies of the C=O stretching modes shifted toward lower energies as the fluid density increased. The density dependence was analyzed by using perturbed hard-sphere theory, and the shift was decomposed into attractive and repulsive energy components. The attractive energy between the ketones and CO2 was up to nine times higher than the repulsive energy, and its magnitude increased in the following order: acetone attractive energy and optimized the relative configuration between each solute and CO2. According to theoretical calculations for the dispersion energy, the dipole-induced-dipole interaction energy, and the frequency shift due to their interactions, the experimentally determined attractive energy differences in the three solutes were attributed to the dispersion energies that depended on a chromophore attached to the carbonyl groups. It was found that the major intermolecular interaction with the attractive shift varied from dipole-induced dipole to dispersion depending on the chromophore in the ketones in scCO2. As the common conclusion for the Raman spectral measurements and the four theoretical calculations, solute polarizability, modified by the chromophore, was at the core of

Report on the results of the twelfth medical examination of atomic bomb survivors residing in North America

International Nuclear Information System (INIS)

Yamamoto, Yasuji; Ohama, Koso; Fujiwara, Saeko

2000-01-01

The twelfth medical examination of atomic bomb survivors residing in North America, was conducted in San Francisco and Seattle from May 20 through June 2 1999, and in Los Angeles and Hawaii from June 9 through 23 1999, The examination included an interview, measurement of height, weight, and blood pressure, an ECG, urine and stool tests, blood tests, a physical examination, examination of the breast, thyroid, and rectum by a surgeon, and screening for uterine cancer and a gynecological interview and examination by an obstetrician and gynecologist. The total confirmed number of A-bomb survivors residing in North America as of the end of June 1999 was 1076. Of the 1062 survivors that remained after excluding the 14 subjects whose survey was incomplete, 279 males and 654 females had been exposed in Hiroshima, and 10 males and 119 females in Nagasaki. The peak age at the time of exposure in both sexes was 15-19 years, followed by 10-14 years. The number of survivors exposed <2000 m from the hypocenter was 236, accounting for 21.9% of the total. The confirmed number of survivors exposed in utero was 26. The survivors' age (mean ±S.D.) was: 69.0±8.69 years; males, 68.4±80.5 years; females, 69.2±8.91 years. A total of 414 survivors were examined (male 129; female 285; mean age 68.0 years). Approximately 80% of the examinees had experienced at least one general symptom. Many still complain of symptoms that suggest possible posttraumatic stress disorder as a result of exposure to the A-bomb. It will be necessary to consider providing mental health care by psychiatrists beginning with the next examination. The prevalence of life-style diseases has been gradually increased with age. A previous history of cancer was found in 9.2% of the examinees. The most prevalent was of breast cancer, followed by malignant tumors of the colon, rectum, uterus, brain, stomach, and thyroid. The need for cancer screening and promotion of life-style education was keenly felt. (K.H.)

Repulsion forces of superplasticizers on ground granulated blast furnace slag in alkaline media, from AFM measurements to rheological properties

Directory of Open Access Journals (Sweden)

Palacios, M.

2012-12-01

Full Text Available The electrostatic and steric repulsion induced by different superplasticizers on ground granulated blast furnace slag in alkaline media have been studied. The superplasticizers were sulfonated naphthalene, sulfonated melamine, vinyl copolymer, and polycarboxylate- based admixtures. With these superplasticizers the slag suspensions had negative zeta potentials, ranging from -3 to -10 mV. For the first time the adsorbed layer thicknesses for superplasticizers on slag using colloidal probe atomic force microscopy has been measured. To model the interparticle force interactions an effective Hamaker constant was computed from dielectric properties measured on a dense slag sample produced by spark plasma sintering. The obtained results conclude that the dispersion mechanism for all the superplasticizers studied in the present work is mainly dominated by the steric repulsion. Results were then used in a yield stress model, YODEL, to predict the yield stress with and without the superplasticizers. Predictions of the yield stress agreed well with experimental results.

En este trabajo se ha estudiado la repulsión electrostática y estérica inducida por diferentes aditivos superplastificantes en sistemas de escoria de horno alto en medios alcalinos. Se han estudiado aditivos superplastificantes basados en naftaleno, melamina, copolímeros vinílicos y basados en policarboxilato. Estos aditivos inducen en la escoria un potencial zeta negativo, entre -3 y -10 mV. Por primera vez, se ha determinado el grosor de la capa de aditivo adsorbido sobre la escoria mediante microscopía de fuerzas atómicas (AFM. Para modelizar las fuerzas de interacción entre partículas, se ha determinado la constante efectiva de Hamaker de la escoria a partir de las propiedades dieléctricas de una muestra de escoria obtenida mediante sinterización spark plasma sintering. Los resultados obtenidos concluyen que el mecanismo de dispersión de los superplastificantes

Fuel performance annual report for 1989

International Nuclear Information System (INIS)

Bailey, W.J.; Berting, F.M.; Wu, S.

1992-06-01

This annual report, the twelfth in a series, provides a brief description of fuel performance during 1989 in commercial nuclear power plants and an indication of trends. Brief summaries of fuel design changes, fuel surveillance programs, fuel operating experience, fuel problems, high-burnup fuel experience, and items of general significance are provided. References to more detailed information and related US Nuclear Regulatory Commission evaluations are included

Environmental issues of Ukrainian energy sector

International Nuclear Information System (INIS)

Streimikiene, D.

2005-01-01

Ukraine's power sector is the twelfth-largest in the world in terms of installed capacity, with 54 GW and Ukraine still obtains over 50% of its electricity usage from nuclear source. In terms of energy consumption per dollar, Ukraine has one of the highest levels of energy and carbon intensity in the world. The country has very huge energy sector which cause a significant impact on environment

Unconventional superconductivity in a two-dimensional repulsive gas of fermions with spin-orbit coupling

Science.gov (United States)

Wang, Luyang; Vafek, Oskar

2014-02-01

We investigate the superconducting instability of a two-dimensional repulsive Fermi gas with Rashba spin-orbit coupling αR. Using renormalization group approach, we find the superconducting transition temperature as a function of the dimensionless ratio Θ=1}/{2}mαR2/EF where EF = 0 when the smaller Fermi surface shrinks to a (Dirac) point. The general trend is that superconductivity is enhanced as Θ increases, but in an intermediate regime Θ ∼ 0.1, a dome-like behavior appears. At a very small value of Θ, the angular momentum channel jz in which superconductivity occurs is quite high. With increasing Θ, jz decreases with a step of 2 down to jz = 6, after which we find the sequence jz = 6, 4, 6, 2, the last value of which continues to Θ → ∞. In an extended range of Θ, the superconducting gap predominantly resides on the large Fermi surface, while Josephson coupling induces a much smaller gap on the small Fermi surface. Below the superconducting transition temperature, we apply mean field theory to derive the self-consistent equations and find the condensation energies. The state with the lowest condensation energy is an unconventional superconducting state which breaks time-reversal symmetry, and in which singlet and triplet pairings are mixed. In general, these states are topologically nontrivial, and the Chern number of the state with total angular momentum jz is C = 2jz.

Supramolecular "Big Bang" in a Single-Ionic Surfactant/Water System Driven by Electrostatic Repulsion: From Vesicles to Micelles.

Science.gov (United States)

Leclercq, Loïc; Bauduin, Pierre; Nardello-Rataj, Véronique

2017-04-11

In aqueous solution, dimethyldi-n-octylammonium chloride, [DiC 8 ][Cl], spontaneously forms dimers at low concentrations (1-10 mM) to decrease the strength of the hydrophobic-water contact. Dimers represent ideal building blocks for the abrupt edification of vesicles at 10 mM. These vesicles are fully characterized by dynamic and static light scattering, self-diffusion nuclear magnetic resonance, and freeze-fracture transmission electron microscopy. An increase in concentration leads to electrostatic repulsion between vesicles that explode into small micelles at 30 mM. These transitions are detected by means of surface tension, conductivity, and solubility of hydrophobic solutes as well as by isothermal titration microcalorimetry. These unusual supramolecular transitions emerge from the surfactant chemical structure that combines two contradictory features: (i) the double-chain structure tending to form low planar aggregates with low water solubility and (ii) the relatively short chains giving high hydrophilicity. The well-balanced hydrophilic-hydrophobic character of [DiC 8 ][Cl] is then believed to be at the origin of the unusual supramolecular sequence offering new opportunities for drug delivery systems.

Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions.

Science.gov (United States)

Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Paineau, E; Bihannic, I; Davidson, P; Meneau, F; Levitz, P; Michot, L J

2011-05-18

Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.

Rheo-SAXS investigation of shear-thinning behaviour of very anisometric repulsive disc-like clay suspensions

International Nuclear Information System (INIS)

Philippe, A M; Baravian, C; Imperor-Clerc, M; De Silva, J; Davidson, P; Paineau, E; Bihannic, I; Michot, L J; Meneau, F; Levitz, P

2011-01-01

Aqueous suspensions of swelling clay minerals exhibit a rich and complex rheological behaviour. In particular, these repulsive systems display strong shear-thinning at very low volume fractions in both the isotropic and gel states. In this paper, we investigate the evolution with shear of the orientational distribution of aqueous clay suspensions by synchrotron-based rheo-SAXS experiments using a Couette device. Measurements in radial and tangential configurations were carried out for two swelling clay minerals of similar morphology and size, Wyoming montmorillonite and Idaho beidellite. The shear evolution of the small angle x-ray scattering (SAXS) patterns displays significantly different features for these two minerals. The detailed analysis of the angular dependence of the SAXS patterns in both directions provides the average Euler angles of the statistical effective particle in the shear plane. We show that for both samples, the average orientation is fully controlled by the local shear stress around the particle. We then apply an effective approach to take into account multiple hydrodynamic interactions in the system. Using such an approach, it is possible to calculate the evolution of viscosity as a function of shear rate from the knowledge of the average orientation of the particles. The viscosity thus recalculated almost perfectly matches the measured values as long as collective effects are not too important in the system.

BmRobo1a and BmRobo1b control axon repulsion in the silkworm Bombyx mori.

Science.gov (United States)

Li, Xiao-Tong; Yu, Qi; Zhou, Qi-Sheng; Zhao, Xiao; Liu, Zhao-Yang; Cui, Wei-Zheng; Liu, Qing-Xin

2016-02-15

The development of the nervous system is based on the growth and connection of axons, and axon guidance molecules are the dominant regulators during this course. Robo, as the receptor of axon guidance molecule Slit, plays a key role as a conserved repellent cue for axon guidance during the development of the central nervous system. However, the function of Robo in the silkworm Bombyx mori is unknown. In this study, we cloned two novel robo genes in B. mori (Bmrobo1a and Bmrobo1b). BmRobo1a and BmRobo1b lack an Ig and a FNIII domain in the extracellular region and the CC0 and CC2 motifs in the intracellular region. BmRobo1a and BmRobo1b were colocalized with BmSlit in the neuropil. Knock-down of Bmrobo1a and Bmrobo1b by RNA interference (RNAi) resulted in abnormal development of axons. Our results suggest that BmRobo1a and BmRobo1b have repulsive function in axon guidance, even though their structures are different from Robo1 of other species. Copyright © 2015 Elsevier B.V. All rights reserved.

Effective diameters and corresponding states of fluids

Science.gov (United States)

Del Río, Fernando

Effective hard-sphere diameters of fluids with purely repulsive interactions are derived from a generalized corresponding-states principle of Leland, Rowlinson and coworkers. Various alternative definitions are discussed and related. Virial expansions of the effective diameters and their corresponding volumes are obtained and compared with results of perturbation theory. Applications are made to inverse-power potentials, the repulsive part of the Lennard-Jones potential and hard spherocylinders and dumbells.

p -wave superconductivity in weakly repulsive 2D Hubbard model with Zeeman splitting and weak Rashba spin-orbit coupling

Science.gov (United States)

Hugdal, Henning G.; Sudbø, Asle

2018-01-01

We study the superconducting order in a two-dimensional square lattice Hubbard model with weak repulsive interactions, subject to a Zeeman field and weak Rashba spin-orbit interactions. Diagonalizing the noninteracting Hamiltonian leads to two separate bands, and by deriving an effective low-energy interaction we find the mean field gap equations for the superconducting order parameter on the bands. Solving the gap equations just below the critical temperature, we find that superconductivity is caused by Kohn-Luttinger-type interaction, while the pairing symmetry of the bands is indirectly affected by the spin-orbit coupling. The dominating attractive momentum channel of the Kohn-Luttinger term depends on the filling fraction n of the system, and it is therefore possible to change the momentum dependence of the order parameter by tuning n . Moreover, n also determines which band has the highest critical temperature. Rotating the magnetic field changes the momentum dependence from states that for small momenta reduce to a chiral px±i py type state for out-of-plane fields, to a nodal p -wave-type state for purely in-plane fields.

Travelling plateaus for a hyperbolic Keller–Segel system with attraction and repulsion: existence and branching instabilities

International Nuclear Information System (INIS)

Perthame, Benoît; Tang, Min; Vauchelet, Nicolas; Schmeiser, Christian

2011-01-01

How can repulsive and attractive forces, acting on a conservative system, create stable travelling patterns or branching instabilities? We have proposed to study this question in the framework of the hyperbolic Keller–Segel system with logistic sensitivity. This is a model system motivated by experiments on cell communities auto-organization, a field which is also called socio-biology. We continue earlier modelling work, where we have shown numerically that branching patterns arise for this system and we have analysed this instability by formal asymptotics for small diffusivity of the chemo-repellent. Here we are interested in the more general situation, where the diffusivities of both the chemo-attractant and the chemo-repellent are positive. To do so, we develop an appropriate functional analysis framework. We apply our method to two cases. Firstly we analyse steady states. Secondly we analyse travelling waves when neglecting the degradation coefficient of the chemo-repellent; the unique wave speed appears through a singularity cancellation which is the main theoretical difficulty. This shows that in different situations the cell density takes the shape of a plateau. The existence of steady states and travelling plateaus are a symptom of how rich the system is and why branching instabilities can occur. Numerical tests show that large plateaus may split into smaller ones, which remain stable

Theatre Review | Various Authors | Shakespeare in Southern Africa

African Journals Online (AJOL)

Twelfth Night: The Port Elizabeth Shakespearean Festival, February 2004; Macbeth: Directed by Geoffrey Hyland, Maynardville Open Air Theatre, January to. February 2004; The Marowitz Hamlet: Directed by Floyed de Vaal for the University of. Stellenbosch Drama Department, July 2004; Bollywood Twelfth Night: Steven ...

Multicritical dynamical phase diagrams of the kinetic Blume-Emery-Griffiths model with repulsive biquadratic coupling in an oscillating field

Energy Technology Data Exchange (ETDEWEB)

Temizer, Umuet [Department of Physics, Bozok University, 66100 Yozgat (Turkey); Kantar, Ersin [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2008-06-15

We study, within a mean-field approach, the stationary states of the kinetic Blume-Emery-Griffiths model with repulsive biquadratic coupling under the presence of a time-varying (sinusoidal) magnetic field. We employ the Glauber-type stochastic dynamics to construct set of dynamic equations of motion. The behavior of the time dependence of the order parameters and the behavior of the average order parameters in a period, which is also called the dynamic order parameters, as functions of the reduced temperature are investigated. The dynamic phase transition points are calculated and phase diagrams are presented in the reduced magnetic field amplitude and reduced temperature plane. The dynamical transition from one regime to the other can be of first- or second order depending on the region in the phase diagram. According to the values of the crystal field interaction or single-ion anisotropy constant and biquadratic exchange constant, we find 20 fundamental types of phase diagrams which exhibit many dynamic critical points, such as tricritical points, zero-temperature critical points, double critical end points, critical end point, triple point and multicritical point. Moreover, besides a disordered and ordered phases, seven coexistence phase regions exist in the system.

Development of an inverse distance weighted active infrared stealth scheme using the repulsive particle swarm optimization algorithm.

Science.gov (United States)

Han, Kuk-Il; Kim, Do-Hwi; Choi, Jun-Hyuk; Kim, Tae-Kuk

2018-04-20

Treatments for detection by infrared (IR) signals are higher than for other signals such as radar or sonar because an object detected by the IR sensor cannot easily recognize its detection status. Recently, research for actively reducing IR signal has been conducted to control the IR signal by adjusting the surface temperature of the object. In this paper, we propose an active IR stealth algorithm to synchronize IR signals from the object and the background around the object. The proposed method includes the repulsive particle swarm optimization statistical optimization algorithm to estimate the IR stealth surface temperature, which will result in a synchronization between the IR signals from the object and the surrounding background by setting the inverse distance weighted contrast radiant intensity (CRI) equal to zero. We tested the IR stealth performance in mid wavelength infrared (MWIR) and long wavelength infrared (LWIR) bands for a test plate located at three different positions on a forest scene to verify the proposed method. Our results show that the inverse distance weighted active IR stealth technique proposed in this study is proved to be an effective method for reducing the contrast radiant intensity between the object and background up to 32% as compared to the previous method using the CRI determined as the simple signal difference between the object and the background.

Comparative molecular simulation study of low and high density polymer glasses: A competition between attractive and repulsive interactions

Science.gov (United States)

Singh, Jalim; Jose, Prasanth

Results of molecular dynamics simulations of a system of Kremer and Grest linear polymer melts are presented at moderate and high number density. A detailed study of molecular pair distribution function shows that potential of mean force between the molecules has form of Gaussian with an attractive tail at number density ρ = 0.85 (in Lennard-Jones units), which is due to the dominating attractive interactions from temperature T = 0.7. This system shows gelation assisted glass transition, which is interpreted from peaks of molecular structure factor at small wave-numbers. At low temperature, this system phase separate to form dense domains whose local density is high; these domains show many dynamical features of glass transition in monomer and molecular level of relaxation indicating glass transition is assisted by gelation in this system. In the same system, at ρ = 1.0, repulsive interactions dominate, structure does not change even at low temperatures; the system exhibits dynamic heterogeneity and known to undergo glass transition. In this work, we compare and contrast the structure and dynamics of the system near its glass transition. Also, we computed correlation length of systems from the peak value of four-point structural dynamic susceptibility. HPC facility at IIT Mandi.

Inversion of particle size distribution by spectral extinction technique using the attractive and repulsive particle swarm optimization algorithm

Directory of Open Access Journals (Sweden)

Qi Hong

2015-01-01

Full Text Available The particle size distribution (PSD plays an important role in environmental pollution detection and human health protection, such as fog, haze and soot. In this study, the Attractive and Repulsive Particle Swarm Optimization (ARPSO algorithm and the basic PSO were applied to retrieve the PSD. The spectral extinction technique coupled with the Anomalous Diffraction Approximation (ADA and the Lambert-Beer Law were employed to investigate the retrieval of the PSD. Three commonly used monomodal PSDs, i.e. the Rosin-Rammer (R-R distribution, the normal (N-N distribution, the logarithmic normal (L-N distribution were studied in the dependent model. Then, an optimal wavelengths selection algorithm was proposed. To study the accuracy and robustness of the inverse results, some characteristic parameters were employed. The research revealed that the ARPSO showed more accurate and faster convergence rate than the basic PSO, even with random measurement error. Moreover, the investigation also demonstrated that the inverse results of four incident laser wavelengths showed more accurate and robust than those of two wavelengths. The research also found that if increasing the interval of the selected incident laser wavelengths, inverse results would show more accurate, even in the presence of random error.

Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

International Nuclear Information System (INIS)

Premnath, Priyatha; Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, Krishnan

2015-01-01

Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel

Tuning cell adhesion by direct nanostructuring silicon into cell repulsive/adhesive patterns

Energy Technology Data Exchange (ETDEWEB)

Premnath, Priyatha, E-mail: priyatha.premnath@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tavangar, Amirhossein, E-mail: atavanga@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Tan, Bo, E-mail: tanbo@ryerson.ca [Nanocharacterization Laboratory, Department of Aerospace Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada); Venkatakrishnan, Krishnan, E-mail: venkat@ryerson.ca [Micro/Nanofabrication Laboratory, Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5B 2K3 (Canada)

2015-09-10

Developing platforms that allow tuning cell functionality through incorporating physical, chemical, or mechanical cues onto the material surfaces is one of the key challenges in research in the field of biomaterials. In this respect, various approaches have been proposed and numerous structures have been developed on a variety of materials. Most of these approaches, however, demand a multistep process or post-chemical treatment. Therefore, a simple approach would be desirable to develop bio-functionalized platforms for effectively modulating cell adhesion and consequently programming cell functionality without requiring any chemical or biological surface treatment. This study introduces a versatile yet simple laser approach to structure silicon (Si) chips into cytophobic/cytophilic patterns in order to modulate cell adhesion and proliferation. These patterns are fabricated on platforms through direct laser processing of Si substrates, which renders a desired computer-generated configuration into patterns. We investigate the morphology, chemistry, and wettability of the platform surfaces. Subsequently, we study the functionality of the fabricated platforms on modulating cervical cancer cells (HeLa) behaviour. The results from in vitro studies suggest that the nanostructures efficiently repel HeLa cells and drive them to migrate onto untreated sites. The study of the morphology of the cells reveals that cells evade the cytophobic area by bending and changing direction. Additionally, cell patterning, cell directionality, cell channelling, and cell trapping are achieved by developing different platforms with specific patterns. The flexibility and controllability of this approach to effectively structure Si substrates to cell-repulsive and cell-adhesive patterns offer perceptible outlook for developing bio-functionalized platforms for a variety of biomedical devices. Moreover, this approach could pave the way for developing anti-cancer platforms that selectively repel

A Local Approximation of Fundamental Measure Theory Incorporated into Three Dimensional Poisson-Nernst-Planck Equations to Account for Hard Sphere Repulsion Among Ions

Science.gov (United States)

Qiao, Yu; Liu, Xuejiao; Chen, Minxin; Lu, Benzhuo

2016-04-01

The hard sphere repulsion among ions can be considered in the Poisson-Nernst-Planck (PNP) equations by combining the fundamental measure theory (FMT). To reduce the nonlocal computational complexity in 3D simulation of biological systems, a local approximation of FMT is derived, which forms a local hard sphere PNP (LHSPNP) model. In the derivation, the excess chemical potential from hard sphere repulsion is obtained with the FMT and has six integration components. For the integrands and weighted densities in each component, Taylor expansions are performed and the lowest order approximations are taken, which result in the final local hard sphere (LHS) excess chemical potential with four components. By plugging the LHS excess chemical potential into the ionic flux expression in the Nernst-Planck equation, the three dimensional LHSPNP is obtained. It is interestingly found that the essential part of free energy term of the previous size modified model (Borukhov et al. in Phys Rev Lett 79:435-438, 1997; Kilic et al. in Phys Rev E 75:021502, 2007; Lu and Zhou in Biophys J 100:2475-2485, 2011; Liu and Eisenberg in J Chem Phys 141:22D532, 2014) has a very similar form to one term of the LHS model, but LHSPNP has more additional terms accounting for size effects. Equation of state for one component homogeneous fluid is studied for the local hard sphere approximation of FMT and is proved to be exact for the first two virial coefficients, while the previous size modified model only presents the first virial coefficient accurately. To investigate the effects of LHS model and the competitions among different counterion species, numerical experiments are performed for the traditional PNP model, the LHSPNP model, the previous size modified PNP (SMPNP) model and the Monte Carlo simulation. It's observed that in steady state the LHSPNP results are quite different from the PNP results, but are close to the SMPNP results under a wide range of boundary conditions. Besides, in both

Spatiotemporal expression of repulsive guidance molecules (RGMs and their receptor neogenin in the mouse brain.

Directory of Open Access Journals (Sweden)

Dianne M A van den Heuvel

Full Text Available Neogenin has been implicated in a variety of developmental processes such as neurogenesis, neuronal differentiation, apoptosis, migration and axon guidance. Binding of repulsive guidance molecules (RGMs to Neogenin inhibits axon outgrowth of different neuronal populations. This effect requires Neogenin to interact with co-receptors of the uncoordinated locomotion-5 (Unc5 family to activate downstream Rho signaling. Although previous studies have reported RGM, Neogenin, and/or Unc5 expression, a systematic comparison of RGM and Neogenin expression in the developing nervous system is lacking, especially at later developmental stages. Furthermore, information on RGM and Neogenin expression at the protein level is limited. To fill this void and to gain further insight into the role of RGM-Neogenin signaling during mouse neural development, we studied the expression of RGMa, RGMb, Neogenin and Unc5A-D using in situ hybridization, immunohistochemistry and RGMa section binding. Expression patterns in the primary olfactory system, cortex, hippocampus, habenula, and cerebellum were studied in more detail. Characteristic cell layer-specific expression patterns were detected for RGMa, RGMb, Neogenin and Unc5A-D. Furthermore, strong expression of RGMa, RGMb and Neogenin protein was found on several major axon tracts such as the primary olfactory projections, anterior commissure and fasciculus retroflexus. These data not only hint at a role for RGM-Neogenin signaling during the development of different neuronal systems, but also suggest that Neogenin partners with different Unc5 family members in different systems. Overall, the results presented here will serve as a framework for further dissection of the role of RGM-Neogenin signaling during neural development.

Tracer des limites, les franchir. Essai sur la notion de frontière, en Syrie, à la fin du deuxième millénaire avant Jésus-Christ

OpenAIRE

Racine-Dognin, Elisabeth

2015-01-01

If, as we would define it, the word “border” indicates a place of contact and exchanges between two spaces rather than a well-drawn line of separation, numerous borders exist: political, social, cultural, linguistic in an Ancient Near East often characterized as “a world without borders” since it shares the same cuneiform culture. From the fourteenth century BC to the beginning of the twelfth, the Syrian States have belonged to successive spheres of influence of powerful empires, Mitanni, Egy...

Reducing Test Anxiety among 12th Grade Students: Iraqi Kurdistan Region/Soran City as an Example

Science.gov (United States)

Faqe, Chiayee Khorshid; Moheddin, Kurdistan Rafiq; Kakamad, Karwan Kakabra

2016-01-01

This study aims at reducing test anxiety among twelfth grade students at Soran city high schools. Throughout the study both quantitative and qualitative methods used to collect data. The participants were 450 twelfth grade students in five schools at Soran City-Kurdistan region of Iraq. Non-random purposive sampling because the students needed…

Dragon (repulsive guidance molecule RGMb) inhibits E-cadherin expression and induces apoptosis in renal tubular epithelial cells.

Science.gov (United States)

Liu, Wenjing; Li, Xiaoling; Zhao, Yueshui; Meng, Xiao-Ming; Wan, Chao; Yang, Baoxue; Lan, Hui-Yao; Lin, Herbert Y; Xia, Yin

2013-11-01

Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45-66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo.

Effects of repulsive three-body force in 12C + 12C scattering at 100A MeV

Directory of Open Access Journals (Sweden)

W.W. Qu

2015-12-01

Full Text Available The angular distribution of 12C + 12C scattering at an incident energy of 100A MeV has been measured. The elastic and inelastic scatterings in 12C to the excitation energies of up to ∼45 MeV were measured simultaneously for the first time with the high-resolution Grand Raiden spectrometer at the Research Center for Nuclear Physics (RCNP. The angular distributions of the elastic scattering to the ground state (01+ and inelastic scattering to the 4.44 MeV (21+ excited state were precisely obtained in the angular range of 1.0°–7.5° with a step of 0.1°. Additionally, the angular distribution was obtained for the sum of the cross sections for excitation energies above the 4.44 MeV state up to 11 MeV, which includes the 7.65 MeV (02+, 9.64 MeV (31−, and 10.30 MeV (22+ states, in addition to probably the simultaneous excitation of the 4.44 MeV state in the projectile and the target nuclei. Those combined data provide a means to study the effects of channel coupling on the elastic cross section. The observed angular distributions are compared with theoretical calculations based on three double-folding models with complex G-matrix interactions, the CEG07b, MPa, and ESC models. The importance of three-body repulsive forces included in the CEG07b and MPa models will be discussed.

Equation of state and Helmholtz free energy for the atomic system of the repulsive Lennard-Jones particles.

Science.gov (United States)

Mirzaeinia, Ali; Feyzi, Farzaneh; Hashemianzadeh, Seyed Majid

2017-12-07

Simple and accurate expressions are presented for the equation of state (EOS) and absolute Helmholtz free energy of a system composed of simple atomic particles interacting through the repulsive Lennard-Jones potential model in the fluid and solid phases. The introduced EOS has 17 and 22 coefficients for fluid and solid phases, respectively, which are regressed to the Monte Carlo (MC) simulation data over the reduced temperature range of 0.6≤T * ≤6.0 and the packing fraction range of 0.1 ≤ η ≤ 0.72. The average absolute relative percent deviation in fitting the EOS parameters to the MC data is 0.06 and 0.14 for the fluid and solid phases, respectively. The thermodynamic integration method is used to calculate the free energy using the MC simulation results. The Helmholtz free energy of the ideal gas is employed as the reference state for the fluid phase. For the solid phase, the values of the free energy at the reduced density equivalent to the close-packed of a hard sphere are used as the reference state. To check the validity of the predicted values of the Helmholtz free energy, the Widom particle insertion method and the Einstein crystal technique of Frenkel and Ladd are employed. The results obtained from the MC simulation approaches are well agreed to the EOS results, which show that the proposed model can reliably be utilized in the framework of thermodynamic theories.

Long-term mortality benefits of air quality improvement during the twelfth five-year-plan period in 31 provincial capital cities of China

Science.gov (United States)

Liu, Tao; Cai, Yuanyuan; Feng, Baixiang; Cao, Ganxiang; Lin, Hualiang; Xiao, Jianpeng; Li, Xing; Liu, Sha; Pei, Lei; Fu, Li; Yang, Xinyi; Zhang, Bo; Ma, Wenjun

2018-01-01

The severe air pollution across China in the past several years has made the Chinese government recognize its significant impacts on public health and society, and take enormous efforts to improve the air quality all over the country, especially during the Twelfth Five-Year Plan (12th FYP). However, the overall effectiveness of these air pollution control policies remains unclear. In this study, we selected the 31 municipalities and provincial capital cities in mainland China as study settings. We collected the annual average population size, mortality rates (total mortality and mortality due to cardiovascular diseases, respiratory diseases, total cancer, lung cancer and breast cancer) and concentrations of air pollutants (PM10, PM2.5, SO2 and NO2) in each capital city from 2010 to 2015 from national or local Statistical Yearbooks. The effect sizes of air pollutants on mortality were obtained from previously published meta analyses or cohort studies. We first estimated the annual mortality rates attributed to the changes in air pollutant concentrations for every city in each year. Then, we further estimated the mortality benefits in the scenarios where the air quality had reached the grade II levels of Chinese Ambient Air Quality Standards (CAAQS) and World Health Organization (WHO) guidelines. In most capital cities, we observed dominant decreases in air pollutant concentrations during the 12th FYP, particularly from 2013 to 2015, which has led to significant mortality benefits for the public. A total of 121,658 deaths (0.441‰) have been prevented due to the decrease of PM2.5concentrations from 2013 to 2015 in all included cities. The morality benefits were larger in capital cities located in the key regions (the three main regions and ten city groups) than the other cities. In addition, more mortality benefits could be obtained in the future if the air quality reaches the grade II levels of Chinese Ambient Air Quality Standards (CAAQS) or WHO guidelines. We

Dragon (Repulsive Guidance Molecule RGMb) Inhibits E-cadherin Expression and Induces Apoptosis in Renal Tubular Epithelial Cells*

Science.gov (United States)

Liu, Wenjing; Li, Xiaoling; Zhao, Yueshui; Meng, Xiao-Ming; Wan, Chao; Yang, Baoxue; Lan, Hui-Yao; Lin, Herbert Y.; Xia, Yin

2013-01-01

Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45–66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo. PMID:24052264

Modelling and analyses do not support the hypothesis that charging by power-line corona increases lung deposition of airborne particles

International Nuclear Information System (INIS)

Jeffers, D.

2007-01-01

The National Radiological Protection Board's advisory Group on Non-ionising Radiation has recommended further study on the effects of electric charge on the deposition of 0.005-1 μm particles in the lung. Estimates have been made regarding the integrated ion exposure within the corona plume generated by a power line and by ionizers in an intensive care unit. Changes in the charge state of particles with sizes in the range 0.02-13 μm have been calculated for these exposures. The corona plume increases the charge per particle of 0.02 and 0.1 μm particles by the order of 0.1. The ionizers in the intensive care unit produced negative ions-as do power lines under most conditions. Bacteria can carry in the order of 1000 charges (of either sign) and it is shown that the repulsion between such a negatively charged bacterium and negative ions prevents further ion deposition by diffusion charging. Positively charged bacteria can, however, be discharged by the ions which are attracted to them. The data provide no support for the hypothesis that ion exposure, at the levels considered, can increase deposition in the lung. (authors)

ANALISISI AMANAT DAN NILAI-NILAI GURINDAM KEDUA BELAS DONGENG BUJANG SRI LADANG

Directory of Open Access Journals (Sweden)

Suhardi Suhardi

2017-06-01

Full Text Available The purpose of this study was to describe the values ​​Gurindam Twelfth contained in Bujang Sri Ladang fairy tale. This study uses an objective approach, the approach that focuses only on work study itself (fairy tale Bujang Sri Ladang. The method used is descriptive method, which describe the values ​​Gurindam Twelfth contained in Bujang Sri Ladang fairy tale. Data collected by interview, the interviewing community leaders in the city of Tanjungpinang fairytale owner, to obtain data related to the fairy tale Bujang Sri Ladang. Data analysis technique conducted by: (1 describe the synopsis legend Ship Island, (2 describe the mandate of the fabled Bujang Sri Ladang, (3 describe the values ​​Gurindam Twelfth contained in a fairy tale Bujang Sri Ladang, and (4 interprets the value -value Gurindam Twelfth contained in Bujang Sri Ladang fairy tale. The results obtained: Bujang Sri Ladang fairytale field contains: Islamic values, the value of faith, social values, manners and character, introspective, benefits, and ethical values. It is as the result of analyzes performed. Those values ​​are the essential values ​​and become a lifeline of society, especially the Malay community Tanjungpinang city

A 2 Tesla Full Scale High Performance Periodic Permanent Magnet Model for Attractive (228 KN) and repulsive Maglev

Science.gov (United States)

Stekly, Z. J. J.; Gardner, C.; Domigan, P.; Baker, J.; Hass, M.; McDonald, C.; Wu, C.; Farrell, R. A.

1996-01-01

Two 214.5 cm. long high performance periodic (26 cm period) permanent magnet half-assemblies were designed and constructed for use as a wiggler using Nd-B-Fe and vanadium permendur as hard and soft magnetic materials by Field Effects, a division of Intermagnetics General Corporation. Placing these assemblies in a supporting structure with a 2.1 cm pole to pole separation resulted in a periodic field with a maximum value of 2.04 T. This is believed to be the highest field ever achieved by this type of device. The attractive force between the two 602 kg magnet assemblies is 228 kN, providing enough force for suspension of a 45,500 kg vehicle. If used in an attractive maglev system with an appropriate flat iron rail, one assembly will generate the same force with a gap of 1.05 cm leading to a lift to weight ratio of 38.6, not including the vehicle attachment structure. This permanent magnet compares well with superconducting systems which have lift to weight ratios in the range of 5 to 10. This paper describes the magnet assemblies and their measured magnetic performance. The measured magnetic field and resulting attractive magnetic force have a negative spring characteristic. Appropriate control coils are necessary to provide stable operation. The estimated performance of the assemblies in a stable repulsive mode, with eddy currents in a conducting guideway, is also discussed.

Thermodynamics of strongly coupled repulsive Yukawa particles in ambient neutralizing plasma: Thermodynamic instability and the possibility of observation in fine particle plasmas

International Nuclear Information System (INIS)

Totsuji, Hiroo

2008-01-01

The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.

Thermodynamics of strongly coupled repulsive Yukawa particles in ambient neutralizing plasma: Thermodynamic instability and the possibility of observation in fine particle plasmas

Science.gov (United States)

Totsuji, Hiroo

2008-07-01

The thermodynamics is analyzed for a system composed of particles with hard cores, interacting via the repulsive Yukawa potential (Yukawa particulates), and neutralizing ambient (background) plasma. An approximate equation of state is given with proper account of the contribution of ambient plasma and it is shown that there exists a possibility for the total isothermal compressibility of Yukawa particulates and ambient plasma to diverge when the coupling between Yukawa particulates is sufficiently strong. In this case, the system undergoes a transition into separated phases with different densities and we have a critical point for this phase separation. Examples of approximate phase diagrams related to this transition are given. It is emphasized that the critical point can be in the solid phase and we have the possibility to observe a solid-solid phase separation. The applicability of these results to fine particle plasmas is investigated. It is shown that, though the values of the characteristic parameters are semiquantitative due to the effects not described by this model, these phenomena are expected to be observed in fine particle plasmas, when approximately isotropic bulk systems are realized with a very strong coupling between fine particles.

Twelfth annual meeting of the International Working Group on Fast Reactors. Summary report. Part II

Energy Technology Data Exchange (ETDEWEB)

NONE

1979-07-01

Examining several alternative nuclear power scenarios through the long term it showed the comparative needs of advanced reactors for uranium and for supporting services, thereby establishing the basis for further development of uranium resources and specific reactor systems. Even with dramatic increases in known resources, nuclear power would be able to play only a temporary role in satisfying world energy needs. The use of advanced fast breeders can do much to reduce the total rate of depletion of uranium resources. Breeder reactors would provide a virtually inexhaustible source of energy supply within foreseeable extensions of known uranium resources. This document includes status reports on activities related to research, development, construction, operation, experimental data, safety issues of fast breeder reactors in Germany, Italy, European Union, USSR, OECD, Japan, USA, UK, France.

Non-universality of vacuum pressure B in hadrons, mass of dilambda and nonperturbative gluonic contribution to the repulsive NN-interaction core

International Nuclear Information System (INIS)

Kondratyuk, L.A.; Krivoruchenko, M.I.; Shchepkin, M.G.

1987-01-01

Vacuum pressure B 6 for six-quark systems is evaluated from a restriction on the admixture of 6q-bag in the deuteron and from the data on the deuteron magnetic moment. The obtained value of B 6 is approximately twice as much as that for the three-quark systems: B 6 /B 3 =1.8-1.9. In the MIT, ITEP and chiral versions of the bag model, masses of the dilambda and the 6q-bag with the deuteron quantum numbers are calculated. The increase of the bag constant B 6 makes the dilambda mass higher by 270-330 MeV; as a consequence the dilambda is no longer bound. The non-universality of B results in an increasing height of the repulsive NN core, which rises from 300 up to 700 MeV. If the core height is 300 MeV (corresponding to B 6 =B 3 ) the derivetive of the NN scattering phase shift in the 3 S 1 channel changes its sigh at T lab ≅ 450 MeV, in contradiction to the experimental data. The behaviour of the phase shift in the interval 100-700 MeV is in a seasonable agreement with the second variant, B 6 > B 3

Floating Chip Mounting System Driven by Repulsive Force of Permanent Magnets for Multiple On-Site SPR Immunoassay Measurements

Science.gov (United States)

Horiuchi, Tsutomu; Tobita, Tatsuya; Miura, Toru; Iwasaki, Yuzuru; Seyama, Michiko; Inoue, Suzuyo; Takahashi, Jun-ichi; Haga, Tsuneyuki; Tamechika, Emi

2012-01-01

We have developed a measurement chip installation/removal mechanism for a surface plasmon resonance (SPR) immunoassay analysis instrument designed for frequent testing, which requires a rapid and easy technique for changing chips. The key components of the mechanism are refractive index matching gel coated on the rear of the SPR chip and a float that presses the chip down. The refractive index matching gel made it possible to optically couple the chip and the prism of the SPR instrument easily via elastic deformation with no air bubbles. The float has an autonomous attitude control function that keeps the chip parallel in relation to the SPR instrument by employing the repulsive force of permanent magnets between the float and a float guide located in the SPR instrument. This function is realized by balancing the upward elastic force of the gel and the downward force of the float, which experiences a leveling force from the float guide. This system makes it possible to start an SPR measurement immediately after chip installation and to remove the chip immediately after the measurement with a simple and easy method that does not require any fine adjustment. Our sensor chip, which we installed using this mounting system, successfully performed an immunoassay measurement on a model antigen (spiked human-IgG) in a model real sample (non-homogenized milk) that included many kinds of interfering foreign substances without any sample pre-treatment. The ease of the chip installation/removal operation and simple measurement procedure are suitable for frequent on-site agricultural, environmental and medical testing. PMID:23202030

Structural behavior and dynamics of an anomalous fluid between attractive and repulsive walls: templating, molding, and superdiffusion.

Science.gov (United States)

Leoni, Fabio; Franzese, Giancarlo

2014-11-07

Confinement can modify the dynamics, the thermodynamics, and the structural properties of liquid water, the prototypical anomalous liquid. By considering a generic model for anomalous liquids, suitable for describing solutions of globular proteins, colloids, or liquid metals, we study by molecular dynamics simulations the effect that an attractive wall with structure and a repulsive wall without structure have on the phases, the crystal nucleation, and the dynamics of the fluid. We find that at low temperatures the large density of the attractive wall induces a high-density, high-energy structure in the first layer ("templating" effect). In turn, the first layer induces a "molding" effect on the second layer determining a structure with reduced energy and density, closer to the average density of the system. This low-density, low-energy structure propagates further through the layers by templating effect and can involve all the existing layers at the lowest temperatures investigated. Therefore, although the high-density, high-energy structure does not self-reproduce further than the first layer, the structured wall can have a long-range influence thanks to a sequence of templating, molding, and templating effects through the layers. We find that the walls also have an influence on the dynamics of the liquid, with a stronger effect near the attractive wall. In particular, we observe that the dynamics is largely heterogeneous (i) among the layers, as a consequence of the sequence of structures caused by the walls presence, and (ii) within the same layer, due to superdiffusive liquid veins within a frozen matrix of particles near the walls at low temperature and high density. Hence, the partial freezing of the first layer does not correspond necessarily to an effective reduction of the channel's section in terms of transport properties, as suggested by other authors.

Ionization of Rb Rydberg atoms in the attractive nsnp dipole-dipole potential

International Nuclear Information System (INIS)

Park, Hyunwook; Shuman, E. S.; Gallagher, T. F.

2011-01-01

We have observed the ionization of a cold gas of Rb Rydberg atoms which occurs when nsns van der Waals pairs of ns atoms of n≅ 40 on a weakly repulsive potential are transferred to an attractive dipole-dipole nsnp potential by a microwave transition. Comparing the measurements to a simple model shows that the initial 300-μK thermal velocity of the atoms plays an important role. Excitation to a repulsive dipole-dipole potential does not lead to more ionization on a 15-μs time scale than leaving the atoms in the weakly repulsive nsns state. This observation is slightly surprising since a radiative transition must occur to allow ionization in the latter case. Finally, by power broadening of the microwave transition, to allow transitions from the initial nsns state to the nsnp state over a broad range of internuclear spacings, it is possible to accelerate markedly the evolution to a plasma.

Development of thermo-plastic heating and compaction facility

International Nuclear Information System (INIS)

Ko, Dae Hak; Lim, Suk Nam

1998-01-01

Low- and intermediate-level radioactive wastes consist of spent resin, spent filter, concentrated waste and dry active waste(DAW) and they are solidified or packaged into drums or high integrated containers(HICs). DAWs occupy 50 percent of all low- and intermediate-level radioactive wastes generated from nuclear power plants in Korea. Incinerable wastes in the DAWs are about 60 percent. Therefore, it is very important for us to reduce the volume of incinerable wastes in DAWs. Experience of supercompaction turned out that thermo-plastic wastes have a swelling effect after supercompaction process due to their repulsive power. And the thermo-plastic heating and compaction facility has been developed by KEPCO. In conclusion, heating and compaction facility can reduce the volume of DAWs as well as upgrade the quality of treated wastes, because the swelling effect by repulsive power after compaction is removed, final wastes form the shape of block and they have no free-standing water in the wastes. Plan for practical use is that this facility will be installed in other nuclear power plants in Korea in 1999. (Cho, G. S.). 1 tab., 2 figs

Consensus together to jointly promote the safe and efficient development of China's Nuclear industry

International Nuclear Information System (INIS)

Lei Zengguang

2012-01-01

After the development of China's nuclear industry 56 years, and a certain ability to form a strategic advantage for sustainable development, laying a solid foundation for the development of the national nuclear energy. 2011 Japan's Fukushima Daiichi nuclear accident occurred seven. 2011 of the 'Economic and Social Development Twelfth Five Five Year plan' clearly stated: 'on the basis of ensuring efficient and safe development of nuclear power', the development of China's nuclear industry is facing unprecedented opportunities and challenges, requiring the nuclear industry and nuclear academia work together to jointly promote China's nuclear industry safe and efficient, development

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation.

Science.gov (United States)

Andrés, Juan; Berski, Sławomir; Silvi, Bernard

2016-07-07

Probing the electron density transfers during a chemical reaction can provide important insights, making possible to understand and control chemical reactions. This aim has required extensions of the relationships between the traditional chemical concepts and the quantum mechanical ones. The present work examines the detailed chemical insights that have been generated through 100 years of work worldwide on G. N. Lewis's ground breaking paper on The Atom and the Molecule (Lewis, G. N. The Atom and the Molecule, J. Am. Chem. Soc. 1916, 38, 762-785), with a focus on how the determination of reaction mechanisms can be reached applying the bonding evolution theory (BET), emphasizing how curly arrows meet electron density transfers in chemical reaction mechanisms and how the Lewis structure can be recovered. BET that combines the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT) provides a powerful tool providing insight into molecular mechanisms of chemical rearrangements. In agreement with physical laws and quantum theoretical insights, BET can be considered as an appropriate tool to tackle chemical reactivity with a wide range of possible applications. Likewise, the present approach retrieves the classical curly arrows used to describe the rearrangements of chemical bonds for a given reaction mechanism, providing detailed physical grounds for this type of representation. The ideas underlying the valence-shell-electron pair-repulsion (VSEPR) model applied to non-equilibrium geometries provide simple chemical explanations of density transfers. For a given geometry around a central atom, the arrangement of the electronic domain may comply or not with the VSEPR rules according with the valence shell population of the considered atom. A deformation yields arrangements which are either VSEPR defective (at least a domain is missing to match the VSEPR arrangement corresponding to the geometry of the ligands), VSEPR compliant

Why LiFePO4 is a safe battery electrode: Coulomb repulsion induced electron-state reshuffling upon lithiation.

Science.gov (United States)

Liu, Xiaosong; Wang, Yung Jui; Barbiellini, Bernardo; Hafiz, Hasnain; Basak, Susmita; Liu, Jun; Richardson, Thomas; Shu, Guojiun; Chou, Fangcheng; Weng, Tsu-Chien; Nordlund, Dennis; Sokaras, Dimosthenis; Moritz, Brian; Devereaux, Thomas P; Qiao, Ruimin; Chuang, Yi-De; Bansil, Arun; Hussain, Zahid; Yang, Wanli

2015-10-21

LiFePO4 is a battery cathode material with high safety standards due to its unique electronic structure. We performed systematic experimental and theoretical studies based on soft X-ray emission, absorption, and hard X-ray Raman spectroscopy of LixFePO4 nanoparticles and single crystals. The results clearly show a non-rigid electron-state reconfiguration of both the occupied and unoccupied Fe-3d and O-2p states during the (de)lithiation process. We focus on the energy configurations of the occupied states of LiFePO4 and the unoccupied states of FePO4, which are the critical states where electrons are removed and injected during the charge and discharge process, respectively. In LiFePO4, the soft X-ray emission spectroscopy shows that, due to the Coulomb repulsion effect, the occupied Fe-3d states with the minority spin sit close to the Fermi level. In FePO4, the soft X-ray absorption and hard X-ray Raman spectroscopy show that the unoccupied Fe-3d states again sit close to the Fermi level. These critical 3d electron state configurations are consistent with the calculations based on modified Becke and Johnson potentials GGA+U (MBJGGA+U) framework, which improves the overall lineshape prediction compared with the conventionally used GGA+U method. The combined experimental and theoretical studies show that the non-rigid electron state reshuffling guarantees the stability of oxygen during the redox reaction throughout the charge and discharge process of LiFePO4 electrodes, leading to the intrinsic safe performance of the electrodes.

Ionic fluids with r-6 pair interactions have power-law electrostatic screening

International Nuclear Information System (INIS)

Kjellander, Roland; Forsberg, Bjoern

2005-01-01

The decay behaviour of radial distribution functions for large distances r is investigated for classical Coulomb fluids where the ions interact with an r -6 potential (e.g. a dispersion interaction) in addition to the Coulombic and the short-range repulsive potentials (e.g. a hard core). The pair distributions and the density-density (NN), charge-density (QN) and charge-charge (QQ) correlation functions are investigated analytically and by Monte Carlo simulations. It is found that the NN correlation function ultimately decays like r -6 for large r, just as it does for fluids of electroneutral particles interacting with an r -6 potential. The prefactor is proportional to the squared compressibility in both cases. The QN correlations decay in general like r -8 and the QQ correlations like r -10 in the ionic fluid. The average charge density around an ion decays generally like r -8 and the average electrostatic potential like r -6 . This behaviour is in stark contrast to the decay behaviour for classical Coulomb fluids in the absence of the r -6 potential, where all these functions decay exponentially for large r. The power-law decays are, however, the same as for quantum Coulomb fluids. This indicates that the inclusion of the dispersion interaction as an effective r -6 interaction potential in classical systems yields the same decay behaviour for the pair correlations as in quantum ionic systems. An exceptional case is the completely symmetric binary electrolyte for which only the NN correlation has a power-law decay but not the QQ correlations. These features are shown by an analysis of the bridge function

Heat conduction in a chain of colliding particles with a stiff repulsive potential

Science.gov (United States)

Gendelman, Oleg V.; Savin, Alexander V.

2016-11-01

One-dimensional billiards, i.e., a chain of colliding particles with equal masses, is a well-known example of a completely integrable system. Billiards with different particle masses is generically not integrable, but it still exhibits divergence of a heat conduction coefficient (HCC) in the thermodynamic limit. Traditional billiards models imply instantaneous (zero-time) collisions between the particles. We relax this condition of instantaneous impact and consider heat transport in a chain of stiff colliding particles with the power-law potential of the nearest-neighbor interaction. The instantaneous collisions correspond to the limit of infinite power in the interaction potential; for finite powers, the interactions take nonzero time. This modification of the model leads to a profound physical consequence—the probability of multiple (in particular triple) -particle collisions becomes nonzero. Contrary to the integrable billiards of equal particles, the modified model exhibits saturation of the heat conduction coefficient for a large system size. Moreover, the identification of scattering events with triple-particle collisions leads to a simple definition of the characteristic mean free path and a kinetic description of heat transport. This approach allows us to predict both the temperature and density dependencies for the HCC limit values. The latter dependence is quite counterintuitive—the HCC is inversely proportional to the particle density in the chain. Both predictions are confirmed by direct numerical simulations.

A Monte Carlo study of the two-dimensional melting mechanism

NARCIS (Netherlands)

Allen, M.P.; Frenkel, D.; Gignac, W.; Mctaque, J.P.

1983-01-01

We report here a Monte Carlo study of the thermodynamic and structural properties of a two-dimensional system of 2500 particles interacting by a repulsive inverse sixth power potential. Particular effort was made in the melting region, both to identify the defect structures and to ascertain the

Short-time dynamics of lysozyme solutions with competing short-range attraction and long-range repulsion: Experiment and theory

Science.gov (United States)

Riest, Jonas; Nägele, Gerhard; Liu, Yun; Wagner, Norman J.; Godfrin, P. Douglas

2018-02-01

Recently, atypical static features of microstructural ordering in low-salinity lysozyme protein solutions have been extensively explored experimentally and explained theoretically based on a short-range attractive plus long-range repulsive (SALR) interaction potential. However, the protein dynamics and the relationship to the atypical SALR structure remain to be demonstrated. Here, the applicability of semi-analytic theoretical methods predicting diffusion properties and viscosity in isotropic particle suspensions to low-salinity lysozyme protein solutions is tested. Using the interaction potential parameters previously obtained from static structure factor measurements, our results of Monte Carlo simulations representing seven experimental lysoyzme samples indicate that they exist either in dispersed fluid or random percolated states. The self-consistent Zerah-Hansen scheme is used to describe the static structure factor, S(q), which is the input to our calculation schemes for the short-time hydrodynamic function, H(q), and the zero-frequency viscosity η. The schemes account for hydrodynamic interactions included on an approximate level. Theoretical predictions for H(q) as a function of the wavenumber q quantitatively agree with experimental results at small protein concentrations obtained using neutron spin echo measurements. At higher concentrations, qualitative agreement is preserved although the calculated hydrodynamic functions are overestimated. We attribute the differences for higher concentrations and lower temperatures to translational-rotational diffusion coupling induced by the shape and interaction anisotropy of particles and clusters, patchiness of the lysozyme particle surfaces, and the intra-cluster dynamics, features not included in our simple globular particle model. The theoretical results for the solution viscosity, η, are in qualitative agreement with our experimental data even at higher concentrations. We demonstrate that semi

Hydrogen detachment driven by a repulsive 1πσ* state - an electron localization function study of 3-amino-1,2,4-triazole.

Science.gov (United States)

Bil, Andrzej; Latajka, Zdzisław; Biczysko, Malgorzata

2018-02-14

Electron localization function analysis reveals the details of a charge induced hydrogen detachment mechanism of 3-amino-1,2,4-triazole, identified recently to be responsible for phototautomerization of the molecule. In this process vertical excitation to the 1 πσ* state is followed by the barrier-less migration of a H atom along the N-H bond toward the conical intersection with the S0 ground state. The most striking feature revealed for the 1 πσ* state is partial ejection of σ* electrons outside the molecule, even beyond the NH group, at the Franck-Condon point. Further gradual spatial localization of the electron around the proton moving along the N-H stretching coordinate gives a plausible explanation for the repulsive character of the 1 πσ* potential energy surface with the proton wading through the region of space where some negative charge is accumulated ('a virtual acceptor'), dragging some electron density. This mechanism resembles the one postulated for the hydrogen transfer from a donor molecule (D-H) to an acceptor one (A) in a class of vertically excited molecules with a preexisting inter- or intramolecular D-HA motif, even though the acceptor molecule is absent. The present analysis demonstrates also that the bond evolution and changes in the electron density along the excited state reaction path can be effectively studied with the use of an electron localization function.

IEEE Conference Record of 1976 Twelfth Modulator Symposium, New York City, 4-5 February 1976.

Science.gov (United States)

1976-01-01

volt, 7 ampere compactness, no standby power, and competitive economi - rms, thyristor in a TO-S can) was also considered. cally. Correspondence with...VI V, J* t2 OA WN.T18 MM EGMLS WMPL MW .TAE Fts Puuu 2B - GeEMTinn nP CLOSEY WACED PULSE BY A SHAM. SCRTNAEY IIIs~ 2 T Sv1 cAi 4.-JI j 1f -W J1YL’ LJ

Proceedings of the 12th Space Photovoltaic Research and Technology Conference (SPRAT 12)

Science.gov (United States)

1993-01-01

The Twelfth Space Photovoltaic Research and Technology conference was held at the NASA Lewis Research Center from 20 to 22 Oct. 1992. The papers and workshops presented in this volume report substantial progress in a variety of areas in space photovoltaics. Topics covered include: high efficiency GaAs and InP solar cells, GaAs/Ge cells as commercial items, flexible amorphous and thin film solar cells (in the early stages of pilot production), high efficiency multiple bandgap cells, laser power converters, solar cell and array technology, heteroepitaxial cells, betavoltaic energy conversion, and space radiation effects in InP cells. Space flight data on a variety of cells were also presented.

Electromechanical Dynamics Simulations of Superconducting LSM Rocket Launcher System in Attractive-Mode

Science.gov (United States)

Yoshida, Kinjiro; Hayashi, Kengo; Takami, Hiroshi

1996-01-01

Further feasibility study on a superconducting linear synchronous motor (LSM) rocket launcher system is presented on the basis of dynamic simulations of electric power, efficiency and power factor as well as the ascending motions of the launcher and rocket. The advantages of attractive-mode operation are found from comparison with repulsive-mode operation. It is made clear that the LSM rocket launcher system, of which the long-stator is divided optimally into 60 sections according to launcher speeds, can obtain high efficiency and power factor.

Multicritical phase diagrams of the Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: the pair approximation and the path probability method with pair distribution

International Nuclear Information System (INIS)

Keskin, Mustafa; Erdinc, Ahmet

2004-01-01

As a continuation of the previously published work, the pair approximation of the cluster variation method is applied to study the temperature dependences of the order parameters of the Blume-Emery-Griffiths model with repulsive biquadratic coupling on a body centered cubic lattice. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. We study the dynamics of the model by the path probability method with pair distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagram in addition to the equilibrium phase diagram and also the first-order phase transition line for the unstable branches of the quadrupole order parameter is superimposed on the phase diagrams. It is found that the metastable phase diagram and the first-order phase boundary for the unstable quadrupole order parameter always exist at the low temperatures which are consistent with experimental and theoretical works

Treatment of metal-laden hazardous wastes with advanced Clean Coal Technology by-products

Energy Technology Data Exchange (ETDEWEB)

James T. Cobb, Jr.; Ronald D. Neufeld; Jana Agostini

1999-04-12

This twelfth quarterly report describes work done during the twelfth three-month period of the University of Pittsburgh's project on the ``Treatment of Metal-Laden Hazardous Wastes with Advanced Clean Coal Technology By-Products.'' This report describes the activities of the project team during the reporting period. The principal work has focused upon new laboratory evaluation of samples from Phase 1, discussions with MAX Environmental Technologies, Inc., on the field work of Phase 2, preparing and giving presentations, and making and responding to a number of outside contacts.

Estimation of Scatterer Diameter by Normalized Power Spectrum of High-Frequency Ultrasonic RF Echo for Assessment of Red Blood Cell Aggregation

Science.gov (United States)

Fukushima, Taku; Hasegawa, Hideyuki; Kanai, Hiroshi

2011-07-01

Red blood cell (RBC) aggregation, as one of the determinants of blood viscosity, plays an important role in blood rheology, including the condition of blood. RBC aggregation is induced by the adhesion of RBCs when the electrostatic repulsion between RBCs weakens owing to increases in protein and saturated fatty acid levels in blood, excessive RBC aggregation leads to various circulatory diseases. This study was conducted to establish a noninvasive quantitative method for assessment of RBC aggregation. The power spectrum of ultrasonic RF echoes from nonaggregating RBCs, which shows the frequency property of scattering, exhibits Rayleigh behavior. On the other hand, ultrasonic RF echoes from aggregating RBCs contain the components of reflection, which have no frequency dependence. By dividing the measured power spectrum of echoes from RBCs in the lumen by that of echoes from a posterior wall of the vein in the dorsum manus, the attenuation property of the propagating medium and the frequency responses of transmitting and receiving transducers are removed from the former spectrum. RBC aggregation was assessed by the diameter of a scatterer, which was estimated by minimizing the square difference between the measured normalized power spectrum and the theoretical power spectrum. In this study, spherical scatterers with diameters of 5, 11, 15, and 30 µm were measured in basic experiments. The estimated scatterer diameters were close to the actual diameters. Furthermore, the transient change of the scatterer diameters were measured in an in vivo experiment with respect to a 24-year-old healthy male during the avascularization using a cuff. The estimated diameters (12-22 µm) of RBCs during avascularization were larger than the diameters (4-8 µm) at rest and after recirculation. These results show the possibility of the use of the proposed method for noninvasive assessment of RBC aggregation.

Influência de práticas maternas no desenvolvimento motor de lactentes do 6º ao 12º meses de vida Influence of child-rearing practices on infants' motor development between the sixth and twelfth months of life

Directory of Open Access Journals (Sweden)

PL Silva

2006-01-01

Full Text Available CONTEXTO: Práticas maternas são comportamentos específicos, por meio dos quais as mães/cuidadores desempenham suas tarefas maternais. Estas práticas poderiam influenciar o desenvolvimento motor de lactentes. OBJETIVO: verificar a influência de práticas maternas, utilizadas no cuidado diário de lactentes saudáveis, sobre seu desenvolvimento motor do 6º ao 12º meses de vida. MÉTODO: Selecionados 14 lactentes, nascidos a termo e saudáveis, avaliados longitudinalmente no 6º, 9º e 12º meses de vida, utilizando-se a Alberta Infant Motor Scale. Em cada avaliação/idade a mãe respondeu a um questionário fechado sobre práticas, predominantemente adotadas no cuidado diário do lactente durante os períodos de vigília. Considerou-se neste estudo a postura predominantemente adotada pelo lactente, local preferencial de permanência e a forma de carregar o lactente no colo. RESULTADOS: No 9º mês de vida o desempenho motor dos lactentes foi influenciado positivamente pela predominância na postura de quatro apoios, em relação à sentada e prono ou supino e pela permanência no chão em relação ao carrinho de bebê. No 12º mês houve influência positiva da predominância na postura de quatro apoios e em pé. A postura predominante no 6º mês de vida e a forma de carregar o lactente no 6º, 9º e 12º meses de vida não influenciaram o desempenho motor do grupo estudado. CONCLUSÃO: Os resultados sugerem que as práticas que estimulam a adoção da postura de quatro apoios e a utilização do chão como local de permanência influenciam positivamente o desenvolvimento motor de lactentes saudáveis a partir do 6º mês de vida.BACKGROUND: Child-rearing practices are defined as specific behavioral patterns used during maternal duties. These practices could influence infants' motor development. OBJECTIVE: To verify the influence of daily child-rearing practices on the motor development of healthy infants from their sixth to twelfth

Predictors of gender achievement in physical science at the secondary level

Science.gov (United States)

Kozlenko, Brittany Hunter

This study used the 2009 National Assessment of Educational Progress (NAEP) science restricted data-set for twelfth graders. The NAEP data used in this research study is derived from a sample group of 11,100 twelfth grade students that represented a national population of over 3,000,000 twelfth grade students enrolled in science in the United States in 2009. The researcher chose the NAEP data set because it provided a national sample using uniform questions. This study investigated how the factors of socioeconomic status (SES), parental education level, mode of instruction, and affective disposition affect twelfth grade students' physical science achievement levels in school for the sample population and subgroups for gender. The factors mode of instruction and affective disposition were built through factor analysis based on available questions from the student surveys. All four factors were found to be significant predictors of physical science achievement for the sample population. NAEP exams are administered to a national sample that represents the population of American students enrolled in public and private schools. This was a non-experimental study that adds to the literature on factors that impact physical science for both genders. A gender gap is essentially nonexistent at the fourth grade level but appears at the eighth grade level in science based on information from NAEP (NCES, 1997). The results of the study can be used to make recommendation for policy change to diminish this gender gap in the future. Educators need to be using research to make instructional decisions; research-based instruction helps all students.

Non-chiral, molecular model of negative Poisson ratio in two dimensions

International Nuclear Information System (INIS)

Wojciechowski, K W

2003-01-01

A two-dimensional model of tri-atomic molecules (in which 'atoms' are distributed on vertices of equilateral triangles, and which are further referred to as cyclic trimers) is solved exactly in the static (zero-temperature) limit for the nearest-neighbour site-site interactions. It is shown that the cyclic trimers form a mechanically stable and elastically isotropic non-chiral phase of negative Poisson ratio. The properties of the system are illustrated by three examples of atom-atom interaction potentials: (i) the purely repulsive (n-inverse-power) potential, (ii) the purely attractive (n-power) potential and (iii) the Lennard-Jones potential which shows both the repulsive and the attractive part. The analytic form of the dependence of the Poisson ratio on the interatomic potential is obtained. It is shown that the Poisson ratio depends, in a universal way, only on the trimer anisotropy parameter both (1) in the limit of n → ∞ for cases (i) and (ii), as well as (2) at the zero external pressure for any potential with a doubly differentiable minimum, case (iii) is an example

Adaptation of superconducting fault current limiter to high-speed reclosing

International Nuclear Information System (INIS)

Koyama, T.; Yanabu, S.

2009-01-01

Using a high temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor might break in some cases because of its excessive generation of heat. Therefore, it is desirable to interrupt early the current that flows to superconductor. So, we proposed the SFCL using an electromagnetic repulsion switch which is composed of a superconductor, a vacuum interrupter and a by-pass coil, and its structure is simple. Duration that the current flow in the superconductor can be easily minimized to the level of less than 0.5 cycle using this equipment. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. There is duty of high-speed reclosing after interrupting fault current in the electric power system. After the fault current is interrupted, the back-up breaker is re-closed within 350 ms. So, the electromagnetic repulsion switch should return to former state and the superconductor should be recovered to superconducting state before high-speed reclosing. Then, we proposed the SFCL using an electromagnetic repulsion switch which employs our new reclosing function. We also studied recovery time of the superconductor, because superconductor should be recovered to superconducting state within 350 ms. In this paper, the recovery time characteristics of the superconducting wire were investigated. Also, we combined the superconductor with the electromagnetic repulsion switch, and we did performance test. As a result, a high-speed reclosing within 350 ms was proven to be possible.

Assessing the attractive/repulsive force balance in axial cyclohexane C-Hax ···Yax contacts: A combined computational analysis in monosubstituted cyclohexanes.

Science.gov (United States)

Silva Lopez, Carlos; Nieto Faza, Olalla; De Proft, Frank; Kolocouris, Antonios

2016-11-15

The interactions of axial substituents in monosubstituted cyclohexane rings are studied in this work using an array of different computational techniques. Additionally, the anomalous axial preference for some bulky substituents is related to stabilizing dispersion interactions. We find that the C-H ax ···Y ax contacts for various substituents with distances ranging from 2 to ∼5 Å may include attractive dispersion forces that can affect the conformational equilibrium; these forces co-exist with Pauli repulsive forces effected by Y ax group due to van der Waals sphere penetration. At distances between 2 and 3 Å stabilizing electron transfer interactions were calculated and the combination of natural bond orbital and QTAIM analysis showed that, in certain cases, Y ax  =  t Bu, C ax -O or C ax  = O or S ax  = O or C ax  = S this interaction can be characterized as an improper H-bond. DFT-D3 and non-covalent interactions calculations (NCIs) in cyclohexane derivatives with Y ax  = SiOR 3 including H Yax ···H cy surfaces at distances ranging between 4 and 6 Å suggest that dispersion has a clear effect on the experimentally observed stabilization of the axial conformer. NCIs computed from the reduced density gradient help to visually identify and analyze these interactions. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Anterior and posterior capsule densitometry levels after femtosecond laser-assisted cataract surgery

Directory of Open Access Journals (Sweden)

Txomin Alberdi

2018-04-01

Full Text Available AIM: To analyze and compare five different variables over one year follow-up (1wk, 1, 3, 6 and 12mo: anterior capsule (AC, and posterior capsule (PC area densitometry values, AC and PC linear densitometry values, and AC opening area reduction ratio after femtosecond laser-assisted cataract surgery. METHODS: This was a prospective comparative study. Seventy-one patients underwent femtosecond laser-assisted cataract surgery on single eye between June 2014 and December 2015. A 5.0 mm diameter laser assisted anterior capsulotomy was performed on all eyes. In every post-surgery evaluation, AC opacificaction (ACO and PC opacification (PCO density levels were provided by Oculus Pentacam®HR using area and linear densitometry methods. Digital images were captured with a slit-lamp Topcon photographic camera and IMAGEnet® 5 software. The AC opening area on the digital images was measured using the Sketchandcalc area calculator and converted to reduction ratio levels. RESULTS: Using Pearson correlation coefficient (PCC, we found no correlation (r=-0.091, P=0.46 in the twelfth month assessment between the evolution of ACO area densitometry values and PCO area densitometry values considered as independent variables. We found no correlation, using PCC (r=-0.096, P=0.43 between the evolution of ACO linear densitometry values and PCO linear densitometry values, in the twelfth month visit, working both as independent variables. AC linear densitometry levels and AC area densitometry levels continued to grow strongly from sixth to twelfth months. Analysis of the values of AC opening area reduction ratio (1wk, 1, 3, 6, 12mo revealed statistically significant differences between the values of successive examinations but the magnitude of the change decreased. In the final period of monitoring between six and twelve months the magnitude of change was low. CONCLUSION: Our results show strong increases of Scheimpflug ACO densitometry values from the sixth to the

Avian radioecology on a nuclear power station site. Technical progress report, 1 July 1974--30 June 1975

International Nuclear Information System (INIS)

Levy, C.K.

1975-01-01

The continuation of a program demonstrating that free-ranging wild birds can be used to assess environmental radionuclide levels is described. Wild passerine birds are trapped at a nuclear power station site and at two control sites, uniquely marked, non-destructively counted for levels of gamma-emitting radionuclides, and released. Subsequent recapture rates are as high as 80 percent for certain species. Nuclides detected included 40 K, 95 Zr- 95 Nb, 137 Cs, and apparent 131 I, the latter at levels just above detection limits (0.07 pCi/g). Significant variations in mean 137 Cs body burdens in Blue Jays and Bobwhite have been observed between sites less than 6 km apart. A significant temporal decrease in 137 Cs body burdens has been observed in various species of birds only at the reactor site. Vegetation and meteorological studies have been initiated to help explain these body-burden differences. The effective half-life of 137 Cs in the Blue Jay is 6.7 +- 1.5 days. The highest observed level of 95 Zr- 95 Nb (1.08 +- 0.07 pCi/g) was in a Grey Catbird. The effective half-life of the 95 Zr- 95 Nb was 69.9 +- 15 days, corresponding to the physical half-life of this isotope pair (65.5d), and the activity abruptly disappeared after the twelfth day of captivity suggesting that it was present in particulate form either on the feathers or skin, or in the bird's pulmonary system. Inter-laboratory comparisons of radionuclide measurements are reported. The number of birds banded during the current reporting period is 2720, while 2047 specimens were radioassayed, an increase of 9 percent and 313 percent, respectively. An exercise to test the practicality of obtaining avian samples from remote sites (i.e., > 50 miles away) for radionuclide measurement was performed satisfactorily. (U.S.)

Short-term effects of sibutramine on mineral status and selected biochemical parameters in obese women.

Science.gov (United States)

Suliburska, Joanna; Bogdański, Paweł; Szulińska, Monika; Pupek-Musialik, Danuta

2012-11-01

The aim of this study was to assess the effect of sibutramine on mineral status and selected biochemical parameters in obese women. The study was conducted on 24 patients who received 15 mg daily doses of sibutramine for 12 weeks, and on 20 patients who received placebo. At the baseline, after the sixth and twelfth weeks of treatment, body weight and blood pressure were measured, the BMI was calculated, and samples of blood and of first morning urine were collected. Serum lipid profiles, glucose levels, and nitric oxide levels were determined. The iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), and magnesium (Mg) present in the serum and urine samples were assessed. The erythrocyte hemolysate of the patients was use to assay the activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). No changes were observed in BMI, blood pressure, or nitric oxide during the study. After 12 weeks of treatment, a decrease was observed in total cholesterol, LDL cholesterol, triglyceride, glucose, and ferritin levels. GSH-Px and SOD activity increased after 12 weeks of sibutramine treatment. The Mg and Cu increases was observed in serum after the sixth and twelfth weeks of treatment. It was found that the Zn level decreased in serum after the twelfth week. The elimination of Ca, Mg, Fe, Zn, and Cu in urine also declined in the twelfth week. No differences were found in the women taking the placebo. In conclusion, we found that sibutramine had a positive effect on lipid and glucose status in obese women. However, the drug disturbed the balance of minerals, especially Zn and Mg, in the subjects.

Educational Technology: Kindergarten through Twelfth Grade.

Science.gov (United States)

Steinhaus, Kurt A.

This report presents the findings and conclusions of a study of educational technology in New Mexico schools. Designed to provide baseline information to the New Mexico Education Technology Planning Committee, the results of the study will also be used to help make statewide planning decisions concerning educational technology. The findings…

A Brief Analysis on the Way to Promote Modern Logistic Operations of Railway Enterprises

Institute of Scientific and Technical Information of China (English)

Li Zengtang

2011-01-01

@@ According to the "Twelfth Five-year Plan of the Economic and Social Development of Sui Fenhe City", the modern logistics industry has been given great priority.To put it more specially, the development of modern logistics industry should be based on the port strategy, and with the aid of tax-free zone, the Sino-Russian Trans-border co operation zone and land- ocean joint transportation.Therefore, during the "twelfth five-year plan" period, our company should understand how to grasp the opportunity, and establish a management model featuring integrated supply chain, to make it play a more important role to the company's rapid developments.

Contribution of on-site Coulomb repulsion energy to structural, electronic and magnetic properties of SrCoO3 for different space groups: first-principles study

Directory of Open Access Journals (Sweden)

Muhammady Shibghatullah

2018-03-01

Full Text Available We report structural, electronic, and magnetic properties of SrCoO3 in Pm3̅m and P4/mbm space groups, which are calculated by using generalized gradient approximation corrected with on-site Coulomb repulsion U and exchange energies J. The cubic lattice parameter a and local magnetic moments of Co (μCo are optimized by varying U at Co 3d site. Employing ultrasoft pseudopotential, the values of U = 8 eV and J = 0.75 eV are the best choice for Pm3̅m space group. We found the value of μCo = 2.56 μB, which is consistent with the previous results. It was also found that Co 3d, hybridized with O 2p, is the main contributor to ferromagnetic metallic properties. Besides, norm-conserving pseudopotential promotes a, which is in good agreement with experimental result. However, it is not suitable for P4/mbm space group. By using ultrasoft pseudopotential, the value of U = 3 eV (J = 0.75 is the most suitable for P4/mbm group. Ferromagnetic metallic properties, Jahn-Teller distortion, and reasonable lattice parameters have been obtained. This study shows that U has significant contribution to the calculated properties and also points out that P4/mbm space group with US-PP is suitable to describe experimental results.

Laser-induced breakdown spectra of Zn2 molecule in the violet region

Indian Academy of Sciences (India)

The study of excimer and van der Waals molecules such as Hg2, Cd2 and Zn2 are of current interest as they are potential candidates for the possible development of new high power excimer lasers. Group IIB metal dimers (Hg2, Cd2 and Zn2) have essentially repulsive ground states with very shallow van der Walls minima.

Popular participation and public hearing by construction of nuclear power plants

International Nuclear Information System (INIS)

Hokimoto, Ichiro

1977-01-01

One of the urgent problems now confronting the atomic power development is to search a legal measure for obtaining the public acceptance with the premise of understanding and cooperation, and it is discussed. Attention is paid to the present status of Japan, in which the legal system is incomplete, and the administrative process unspecified in laws and ordinances must be considered seriously. The first section deals with the public hearing and its problems concerning the installation of reactors. The list of twelve main problems that were pointed out in the manual of holding the public hearing by the council of Japanese scientists is given. The most important points are as follows: (a) the public hearing must be held at such time that the feed back is possible to reflect the points of discussion to the final determination; (b) enough data and information must be provided and noticed beforehand, and the sufficient opportunity of discussion must be ensured; and (c) the scientists recommended by local inhabitants must be included in order to assist laity, and the points of discussion must be adjusted scientifically. The second section deals with the popular participation in fact. In conclusion, it is said that there are several traps in the ''inhabitant participation'', and it is the danger to change into the ''engineering of consent'' which fulfill buffer functions for expecting and avoiding the repulsion and criticism of inhabitants against the administration. It may be only eyes of scientists to check the dark reversal from the conveyance of will and ideas of inhabitants to the authority. (Iwakiri, K.)

Beginning Power BI with Excel 2013 self-service business intelligence using Power Pivot, Power View, Power Query, and Power Map

CERN Document Server

Clark, Dan

2014-01-01

Understanding your company's data has never been easier than with Microsoft's new Power BI package for Excel 2013. Consisting of four powerful tools-Power Pivot, Power View, Power Query and Power Maps-Power BI makes self-service business intelligence a reality for a wide range of users, bridging the traditional gap between Excel users, business analysts and IT experts and making it easier for everyone to work together to build the data models that can give you game-changing insights into your business. Beginning Power BI with Excel 2013 guides you step by step through the process of analyzin

Report to Congress on abnormal occurrences, January--March 1978

International Nuclear Information System (INIS)

1978-01-01

Section 208 of the Energy Reorganization Act of 1974 identifies an abnormal occurrence as an unscheduled incident or event which the Nuclear Regulatory Commission determines to be significant from the standpoint of public health or safety and requires a quarterly report of such events to be made to Congress. The report, the twelfth in the series, covers the period from January 1 to March 31, 1978. The following incidents or events in that time period were determined by the Commission to be significant and reportable: (1) There was one abnormal occurrence at the 68 nuclear power plants licensed to operate. The event involved insulation failures in containment electrical penetrations. (2) There were no abnormal occurrences at fuel cycle facilities (other than nuclear power plants). (3) There were no abnormal occurrences at other license facilities. (4) There was one abnormal occurrence reported by an Agreement State Licensee. The event involved an overexposure of a radiographer. The report also contains information updating previously reported abnormal occurrences

Issues Regarding the Blandford-Znajek Process as a Gamma-Ray Burst Inner Engine

International Nuclear Information System (INIS)

Lee, Hyun Kyu; Brown, G. E.; Wijers, R. A. M. J.

2000-01-01

Several issues regarding the Blandford-Znajek process are discussed to demonstrate that it can be an effective mechanism for powering gamma-ray bursts. Using a simple circuit analysis, it is argued that the disk power increases the effective power of the black hole accretion disk system, although a part of the disk power can be dissipated into black hole entropy. Within the framework of a force-free magnetosphere with a strong magnetic field, a magnetically dominated MHD flow is found to support the Blandford-Znajek process, and it is demonstrated that the possible magnetic repulsion by the rotating black hole will not affect the efficiency substantially. (c) 2000 The American Astronomical Society

Packings of a charged line on a sphere.

Science.gov (United States)

Alben, Silas

2008-12-01

We find equilibrium configurations of open and closed lines of charge on a sphere, and track them with respect to varying sphere radius. Closed lines transition from a circle to a spiral-like shape through two low-wave-number bifurcations-"baseball seam" and "twist"-which minimize Coulomb energy. The spiral shape is the unique stable equilibrium of the closed line. Other unstable equilibria arise through tip-splitting events. An open line transitions smoothly from an arc of a great circle to a spiral as the sphere radius decreases. Under repulsive potentials with faster-than-Coulomb power-law decay, the spiral is tighter in initial stages of sphere shrinkage, but at later stages of shrinkage the equilibria for all repulsive potentials converge on a spiral with uniform spacing between turns. Multiple stable equilibria of the open line are observed.

Wind Power - A Power Source Enabled by Power Electronics

DEFF Research Database (Denmark)

Blaabjerg, Frede; Chen, Zhe

2004-01-01

. The deregulation of energy has lowered the investment in bigger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. The production, distribution and the use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should be set up...... the conventional, fossil (and short term) based energy sources to renewable energy sources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...

Introduction into thermodynamics. From elements to technical applications. 13. rev. and enl. ed.

International Nuclear Information System (INIS)

Cerbe, G.; Hoffmann, H.J.

2002-01-01

This textbook has been proved for more than 30 years and has been regularly revised and updated. Thus, recent developments in energy conversion and environmental protection have constantly been taken into account. Tabulated values and standards reflect the current state of things. The book's basic concept was maintained without change from the first to the twelfth edition: leading over from well-founded thermodynamic theory to technical applications, closeness to practice because of many examples with solutions and tasks with solution results, the opportunity for self-study with 130 examples, 135 tasks and 175 control questions with answers, and high usability because of many tables and direct-information diagrams. The 13th edition was actualised and enhanced by combined-cycle power plants and fuel cells. (orig./GL) [de

Non-chiral, auxetic system of noncentrosymmetric molecules in two dimensions

International Nuclear Information System (INIS)

Wojciechowski, K.W.

2002-12-01

A two-dimensional model of tri-atomic molecules (which 'atoms' are distributed on vertices of equilateral triangles, and which are further referred to as cyclic trimers) is solved exactly in the static (zero-temperature) limit for the nearest-neighbor site-site interactions. It is shown that the cyclic trimers (noncentrosymmetric by the definition) can form a mechanically stable and elastically isotropic non-chiral phase of negative Poisson ratio. The properties of the system are illustrated by three examples of the atom-atom interaction potentials: (i) the purely repulsive (n-inverse-power) potential, (ii) the purely attractive (n-power) potential and (iii) the Lennard-Jones-like potential which shows both the repulsive and the attractive part. The analytic form of the dependence of the Poisson ratio on the interatomic potential is obtained. It is shown that the Poisson ratio depends, in a universal way, only on the trimer anisotropy parameter both (1) in the limit of n → ∞ for the cases (i) and (ii), as well as (2) at the zero external pressure for any potential with a doubly differentiable minimum, the case (iii) is an example. (author)

Efficiency of rejection-free methods for dynamic Monte Carlo studies of off-lattice interacting particles

KAUST Repository

Guerra, Marta L.; Novotny, M. A.; Watanabe, Hiroshi; Ito, Nobuyasu

2009-01-01

We calculate the efficiency of a rejection-free dynamic Monte Carlo method for d -dimensional off-lattice homogeneous particles interacting through a repulsive power-law potential r-p. Theoretically we find the algorithmic efficiency in the limit of low temperatures and/or high densities is asymptotically proportional to ρ (p+2) /2 T-d/2 with the particle density ρ and the temperature T. Dynamic Monte Carlo simulations are performed in one-, two-, and three-dimensional systems with different powers p, and the results agree with the theoretical predictions. © 2009 The American Physical Society.

Efficiency of rejection-free methods for dynamic Monte Carlo studies of off-lattice interacting particles

KAUST Repository

Guerra, Marta L.

2009-02-23

We calculate the efficiency of a rejection-free dynamic Monte Carlo method for d -dimensional off-lattice homogeneous particles interacting through a repulsive power-law potential r-p. Theoretically we find the algorithmic efficiency in the limit of low temperatures and/or high densities is asymptotically proportional to ρ (p+2) /2 T-d/2 with the particle density ρ and the temperature T. Dynamic Monte Carlo simulations are performed in one-, two-, and three-dimensional systems with different powers p, and the results agree with the theoretical predictions. © 2009 The American Physical Society.

Using Curved Crystals to Study Terrace-Width Distributions.

Science.gov (United States)

Einstein, Theodore L.

Recent experiments on curved crystals of noble and late transition metals (Ortega and Juurlink groups) have renewed interest in terrace width distributions (TWD) for vicinal surfaces. Thus, it is timely to discuss refinements of TWD analysis that are absent from the standard reviews. Rather than by Gaussians, TWDs are better described by the generalized Wigner surmise, with a power-law rise and a Gaussian decay, thereby including effects evident for weak step repulsion: skewness and peak shifts down from the mean spacing. Curved crystals allow analysis of several mean spacings with the same substrate, so that one can check the scaling with the mean width. This is important since such scaling confirms well-established theory. Failure to scale also can provide significant insights. Complicating factors can include step touching (local double-height steps), oscillatory step interactions mediated by metallic (but not topological) surface states, short-range corrections to the inverse-square step repulsion, and accounting for the offset between adjacent layers of almost all surfaces. We discuss how to deal with these issues. For in-plane misoriented steps there are formulas to describe the stiffness but not yet the strength of the elastic interstep repulsion. Supported in part by NSF-CHE 13-05892.

Power program and nuclear power

International Nuclear Information System (INIS)

Chernilin, Yu.F.

1990-01-01

Main points of the USSR power program and the role of nuclear power in fuel and power complex of the country are considered. Data on dynamics of economic indices of electric power generation at nuclear power plants during 1980-1988 and forecasts till 2000 are presented. It is shown that real cost of 1 kW/h of electric power is equal to 1.3-1.8 cop., and total reduced cost is equal to 1.8-2.4 cop

Proceedings of the Adaptive Sensor Array Processing Workshop (12th) Held in Lexington, MA on 16-18 March 2004 (CD-ROM)

National Research Council Canada - National Science Library

James, F

2004-01-01

...: The twelfth annual workshop on Adaptive Sensor Array Processing presented a diverse agenda featuring new work on adaptive methods for communications, radar and sonar, algorithmic challenges posed...

Introduction to electrical power and power electronics

CERN Document Server

Patel, Mukund R

2012-01-01

Power Generation, Distribution, and Utilization AC Power Fundamentals Common Aspects of Power Equipments AC Generator AC and DC Motors Transformer Power Cable Power Distribution Fault Current Analysis System ProtectionEconomic Use of PowerElectrochemical BatteryPower Electronics and Motor Drives Power Electronics Devices DC-DC Converters AC-DC-AC Converters Variable-Frequency Drives Quality of Power Power Converter CoolingAppendixIndex

Firm-level determinants of energy and carbon intensity in China

International Nuclear Information System (INIS)

Cao, Jing; Karplus, Valerie J.

2014-01-01

In recent years, China's leaders have sought to coordinate official energy intensity reduction targets with new targets for carbon dioxide (CO 2 ) intensity reduction. The Eleventh Five-Year Plan (2006–2010) included for the first time a binding target for energy intensity, while a binding target for CO 2 intensity was included later in the Twelfth Five-Year Plan (2011–2015). Using panel data for a sample of industrial firms in China covering 2005 to 2009, we investigate the drivers of energy intensity reduction (measured in terms of direct primary energy use and electricity use) and associated CO 2 intensity reduction. Rising electricity prices were associated with decreases in electricity intensity and increases in primary energy intensity, consistent with a substitution effect. Overall, we find that energy intensity reduction by industrial firms during the Eleventh Five-Year Plan translated into more than proportional CO 2 intensity reduction because reducing coal use—in direct industrial use as well as in the power sector—was a dominant abatement strategy. If similar dynamics characterize the Twelfth Five-Year Plan (2011–2015), the national 17 percent CO 2 intensity reduction target may not be difficult to meet—and the 16 percent energy intensity reduction target may result in significantly greater CO 2 intensity reduction. - Highlights: • We describe China's Eleventh Five-Year Plan energy policies. • We examine the drivers of energy, electricity and carbon intensity reduction. • Higher electricity prices correlated with reductions in industrial electricity intensity. • Energy intensity reduction efforts were effective at reducing carbon intensity

76 FR 43723 - Certain Foam Footwear; Final Commission Determination of Violation; Issuance of a General...

Science.gov (United States)

2011-07-21

... as to the trade dress allegation on September 11, 2006. A twelfth respondent, Old Dominion Footwear..., advertising, distributing, offering for sale, transferring (except for exportation), and soliciting U.S...

Power theories for improved power quality

CERN Document Server

Pasko, Marian

2012-01-01

Power quality describes a set of parameters of electric power and the load’s ability to function properly under specific conditions. It is estimated that problems relating to power quality costs the European industry hundreds of billions of Euros annually. In contrast, financing for the prevention of these problems amount to fragments of these costs. Power Theories for Improved Power Quality addresses this imbalance by presenting and assessing a range of methods and problems related to improving the quality of electric power supply. Focusing particularly on active compensators and the DSP based control algorithms, Power Theories for Improved Power Quality introduces the fundamental problems of electrical power. This introduction is followed by chapters which discuss: •‘Power theories’ including their historical development and application to practical problems, •operational principles of active compensator’s DSP control based algorithms using examples and results from laboratory research, and •t...

Collective modes in simple melts: Transition from soft spheres to the hard sphere limit.

Science.gov (United States)

Khrapak, Sergey; Klumov, Boris; Couëdel, Lénaïc

2017-08-11

We study collective modes in a classical system of particles with repulsive inverse-power-law (IPL) interactions in the fluid phase, near the fluid-solid coexistence (IPL melts). The IPL exponent is varied from n = 10 to n = 100 to mimic the transition from moderately soft to hard-sphere-like interactions. We compare the longitudinal dispersion relations obtained using molecular dynamic (MD) simulations with those calculated using the quasi-crystalline approximation (QCA) and find that this simple theoretical approach becomes grossly inaccurate for [Formula: see text]. Similarly, conventional expressions for high-frequency (instantaneous) elastic moduli, predicting their divergence as n increases, are meaningless in this regime. Relations of the longitudinal and transverse elastic velocities of the QCA model to the adiabatic sound velocity, measured in MD simulations, are discussed for the regime where QCA is applicable. Two potentially useful freezing indicators for classical particle systems with steep repulsive interactions are discussed.

Multicritical phase diagrams of the ferromagnetic spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: The cluster variation method and the path probability method with the point distribution

Energy Technology Data Exchange (ETDEWEB)

Keskin, Mustafa [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)], E-mail: keskin@erciyes.edu.tr; Canko, Osman [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)

2008-01-15

We study the thermal variations of the ferromagnetic spin-3/2 Blume-Emery-Griffiths (BEG) model with repulsive biquadratic coupling by using the lowest approximation of the cluster variation method (LACVM) in the absence and presence of the external magnetic field. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. The classification of the stable, metastable and unstable states is made by comparing the free energy values of these states. We also study the dynamics of the model by using the path probability method (PPM) with the point distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagrams in addition to the equilibrium phase diagrams in the (kT/J, K/J) and (kT/J, D/J) planes. It is found that the metastable phase diagrams always exist at the low temperatures, which are consistent with experimental and theoretical works.

Multicritical phase diagrams of the ferromagnetic spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases: The cluster variation method and the path probability method with the point distribution

International Nuclear Information System (INIS)

Keskin, Mustafa; Canko, Osman

2008-01-01

We study the thermal variations of the ferromagnetic spin-3/2 Blume-Emery-Griffiths (BEG) model with repulsive biquadratic coupling by using the lowest approximation of the cluster variation method (LACVM) in the absence and presence of the external magnetic field. We obtain metastable and unstable branches of the order parameters besides the stable branches and phase transitions of these branches are investigated extensively. The classification of the stable, metastable and unstable states is made by comparing the free energy values of these states. We also study the dynamics of the model by using the path probability method (PPM) with the point distribution in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. We present the metastable phase diagrams in addition to the equilibrium phase diagrams in the (kT/J, K/J) and (kT/J, D/J) planes. It is found that the metastable phase diagrams always exist at the low temperatures, which are consistent with experimental and theoretical works

Dynamic phase transition and multicritical dynamic phase diagrams of the kinetic spin-3/2 Blume Emery Griffiths model with repulsive biquadratic coupling under a time-dependent oscillating external field

Science.gov (United States)

Deviren, Bayram; Keskin, Mustafa; Canko, Osman

2008-03-01

We extend our recent paper [O. Canko, B. Deviren, M. Keskin, J. Phys.: Condens. Mater 118 (2006) 6635] to present a study, within a mean-field approach, the stationary states of the kinetic spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic interaction under the presence of a time varying (sinusoidal) magnetic field. We found that the dynamic phase diagrams of the present work exhibit more complex, richer and more topological different types of phase diagrams than our recent paper. Especially, the obtained dynamic phase diagrams show the ferrimagnetic ( i) phase in addition to the ferromagnetic ±3/2 ( f), ferromagnetic ±1/2 ( f), antiquadrupolar or staggered ( a) and disordered ( d) phases, and the f+i, f+d, i+d, f+i+d, a+d and/or f+i+a coexistence regions in addition to the f+f, f+d, f+a, f+d and/or f+a+d coexistence regions, depending on interaction parameters. Moreover, the phase diagrams exhibit dynamic zero-temperature critical, critical end, double critical end, multicritical, and/or pentacritical special points in addition to the dynamic tricritical, double critical end point, triple, quadruple and/or tetracritical special points that depending on the interaction parameters.

Economics of nuclear electricity

International Nuclear Information System (INIS)

Frederick, G.

1997-01-01

On the sites of Tihange and Doel in Belgium, a total of seven nuclear generating units with an aggregate installed power of 5807 MWe are operated. Construction of another unit at Doel was postponed indefinitely in 1988 after the Chernobyl accident. Electrabel holds a 25% interest in the Chooz B-1 and B-2 nuclear generating units under construction in France near the Belgian border. In terms of gross installed nuclear generating capacity worldwide, Belgium holds twelfth place; when ranked according to the contribution to public electricity supply, the country holds third place with a 57% share. Before decisions are taken about future nuclear power plants, above all the fuel costs of gas-fired cogeneration plants and the capital costs of nuclear power plants must be weighed. Current evaluation of all costs shows the use of nuclear power for electricity generation to be ten percent more expensive than that of natural gas. However, those responsible in the power supply industry feel that this short-term competitive situation is only one factor out of many others, such as safety issues, diversification in sourcing and deliveries, climatic influences, and employment. The development and construction of advanced reactors will result in the desired cost reduction and lead to a new era of nuclear power, also in Europe. (orig.) [de

Wind power - a power source now enabled by power electronics

DEFF Research Database (Denmark)

Blaabjerg, Frede; Iov, Florin

2007-01-01

energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...

Comparison between Different Power Sources for Emergency Power Supply at Nuclear Power Plants

International Nuclear Information System (INIS)

Lenasson, Magnus

2015-01-01

Currently the Swedish nuclear power plants are using diesel generator sets and to some extent gas turbines as their emergency AC power sources and batteries as their emergency DC power sources. In the laws governing Swedish nuclear activity, no specific power sources are prescribed. On the other hand, diversification of safety functions should be considered, as well as simplicity and reliability in the safety systems. So far the choices of emergency power sources have been similar between different power plants, and therefore this project investigated a number of alternative power sources and if they are suitable for use as emergency power on nuclear power plants. The goals of the project were to: - Define the parameters that are essential for rending a power source suitable for use at a nuclear power plant. - Present the characteristics of a number of power sources regarding the defined parameters. - Compile the suitability of the different power sources. - Make implementation suggestions for the less conventional of the investigated power sources. (unconventional in the investigated application) 10 different power sources in total have been investigated and to various degrees deemed suitable Out of the 10 power sources, diesel generators, batteries and to some extent gas turbines are seen as conventional technology at the nuclear power plants. In relation to them the other power sources have been assessed regarding diversification gains, foremost with regards to external events. The power sources with the largest diversification gains are: Internal steam turbine, Hydro power, Thermoelectric generators. The work should first and foremost put focus on the fact that under the right circumstances there are power sources that can complement conventional power sources and yield substantial diversification gains. This paper is a shortened version of the report 'Comparison between different power sources for emergency power supply at nuclear power plants'. The

76 FR 63612 - National Committee on Foreign Medical Education and Accreditation Meeting

Science.gov (United States)

2011-10-13

..., 550 Twelfth Street, SW., Washington, DC 20202. Due to security restrictions, all attendees must pre... the Federal Register and the Code of Federal Regulations is available via the Federal Digital System...

Acoustic attraction, repulsion and radiation force cancellation on a pair of rigid particles with arbitrary cross-sections in 2D: Circular cylinders example

Science.gov (United States)

Mitri, F. G.

2017-11-01

The acoustic radiation forces arising on a pair of sound impenetrable cylindrical particles of arbitrary cross-sections are derived. Plane progressive, standing or quasi-standing waves with an arbitrary incidence angle are considered. Multiple scattering effects are described using the multipole expansion formalism and the addition theorem of cylindrical wave functions. An effective incident acoustic field on a particular object is determined, and used with the scattered field to derive closed-form analytical expressions for the radiation force vector components. The mathematical expressions for the radiation force components are exact, and have been formulated in partial-wave series expansions in cylindrical coordinates involving the angle of incidence, the reflection coefficient forming the progressive or the (quasi)standing wave field, the addition theorem, and the expansion coefficients. Numerical examples illustrate the analysis for two rigid circular cross-sections immersed in a non-viscous fluid. Computations for the dimensionless radiation force functions are performed with emphasis on varying the angle of incidence, the interparticle distance, the sizes of the particles as well as the characteristics of the incident field. Depending on the interparticle distance and angle of incidence, one of the particles yields neutrality; it experiences no force and becomes unresponsive (i.e., ;invisible;) to the linear momentum transfer of the effective incident field due to multiple scattering cancellation effects. Moreover, attractive or repulsive forces between the two particles may arise depending on the interparticle distance, the angle of incidence and size parameters of the particles. This study provides a complete analytical method and computations for the axial and transverse radiation force components in multiple acoustic scattering encompassing the cases of plane progressive, standing or quasi-standing waves of arbitrary incidence by a pair of scatterers

The power of PowerPoint.

Science.gov (United States)

Niamtu , J

2001-08-01

Carousel slide presentations have been used for academic and clinical presentations since the late 1950s. However, advances in computer technology have caused a paradigm shift, and digital presentations are quickly becoming standard for clinical presentations. The advantages of digital presentations include cost savings; portability; easy updating capability; Internet access; multimedia functions, such as animation, pictures, video, and sound; and customization to augment audience interest and attention. Microsoft PowerPoint has emerged as the most popular digital presentation software and is currently used by many practitioners with and without significant computer expertise. The user-friendly platform of PowerPoint enables even the novice presenter to incorporate digital presentations into his or her profession. PowerPoint offers many advanced options that, with a minimal investment of time, can be used to create more interactive and professional presentations for lectures, patient education, and marketing. Examples of advanced PowerPoint applications are presented in a stepwise manner to unveil the full power of PowerPoint. By incorporating these techniques, medical practitioners can easily personalize, customize, and enhance their PowerPoint presentations. Complications, pitfalls, and caveats are discussed to detour and prevent misadventures in digital presentations. Relevant Web sites are listed to further update, customize, and communicate PowerPoint techniques.

Water Power Research | Water Power | NREL

Science.gov (United States)

Water Power Research Water Power Research NREL conducts water power research; develops design tools ; and evaluates, validates, and supports the demonstration of innovative water power technologies. Photo of a buoy designed around the oscillating water column principle wherein the turbine captures the

An overview-probabilistic safety analysis for research reactors

International Nuclear Information System (INIS)

Liu Jinlin; Peng Changhong

2015-01-01

For long-term application, Probabilistic Safety Analysis (PSA) has proved to be a valuable tool for improving the safety and reliability of power reactors. In China, 'Nuclear safety and radioactive pollution prevention 'Twelfth Five Year Plan' and the 2020 vision' raises clearly that: to develop probabilistic safety analysis and aging evaluation for research reactors. Comparing with the power reactors, it reveals some specific features in research reactors: lower operating power, lower coolant temperature and pressure, etc. However, the core configurations may be changed very often and human actions play an important safety role in research reactors due to its specific experimental requirement. As a result, there is a necessary to conduct the PSA analysis of research reactors. This paper discusses the special characteristics related to the structure and operation and the methods to develop the PSA of research reactors, including initiating event analysis, event tree analysis, fault tree analysis, dependent failure analysis, human reliability analysis and quantification as well as the experimental and external event evaluation through the investigation of various research reactors and their PSAs home and abroad, to provide the current situation and features of research reactors PSAs. (author)

Power control device of an atomic power plant

International Nuclear Information System (INIS)

Ootsuka, Shiro; Ito, Takero.

1980-01-01

Purpose: To improve the power controllability of an atomic power plant by improving the controllability, response and stability of the recirculation flow rate. Constitution: The power control device comprises a power detector of the reactor, which detects and operates the reactor power from the thermal power, neutron flux or the process quantity controlling the same, and a deviation detector which seeks deviation between the power signal of the power detector and the power set value of the reactor or power station. By use of the power control device constituted in this manner, the core flow rate is regulated by the power signal of the deviation detector thereby to control the power. (Aizawa, K.)

DC power supplies power management and surge protection for power electronic systems

CERN Document Server

Kularatna, Nihal

2011-01-01

Modern electronic systems, particularly portable consumer electronic systems and processor based systems, are power hungry, compact, and feature packed. This book presents the most essential summaries of the theory behind DC-DC converter topologies of both linear and switching types. The text discusses power supply characteristics and design specifications based on new developments in power management techniques and modern semiconductors entering into the portable electronics market. The author also addresses off-the-line power supplies, digital control of power supply, power supply protection

diagnosing the diagnostics: misconceptions of twelfth grade ...

African Journals Online (AJOL)

Preferred Customer

In the area of chemical research, a significant number of studies involving ... be introduced as similar concepts in early high school (3). Second, the ..... misconceptions about physics concepts in Yasin, K. (2004), a M.Sc. dissertation thesis.

Power generation by nuclear power plants

International Nuclear Information System (INIS)

Bacher, P.

2004-01-01

Nuclear power plays an important role in the world, European (33%) and French (75%) power generation. This article aims at presenting in a synthetic way the main reactor types with their respective advantages with respect to the objectives foreseen (power generation, resources valorization, waste management). It makes a fast review of 50 years of nuclear development, thanks to which the nuclear industry has become one of the safest and less environmentally harmful industry which allows to produce low cost electricity: 1 - simplified description of a nuclear power generation plant: nuclear reactor, heat transfer system, power generation system, interface with the power distribution grid; 2 - first historical developments of nuclear power; 3 - industrial development and experience feedback (1965-1995): water reactors (PWR, BWR, Candu), RBMK, fast neutron reactors, high temperature demonstration reactors, costs of industrial reactors; 4 - service life of nuclear power plants and replacement: technical, regulatory and economical lifetime, problems linked with the replacement; 5 - conclusion. (J.S.)

Autonomous power networks based power system

International Nuclear Information System (INIS)

Jokic, A.; Van den Bosch, P.P.J.

2006-01-01

This paper presented the concept of autonomous networks to cope with this increased complexity in power systems while enhancing market-based operation. The operation of future power systems will be more challenging and demanding than present systems because of increased uncertainties, less inertia in the system, replacement of centralized coordinating activities by decentralized parties and the reliance on dynamic markets for both power balancing and system reliability. An autonomous network includes the aggregation of networked producers and consumers in a relatively small area with respect to the overall system. The operation of an autonomous network is coordinated and controlled with one central unit acting as an interface between internal producers/consumers and the rest of the power system. In this study, the power balance problem and system reliability through provision of ancillary services was formulated as an optimization problem for the overall autonomous networks based power system. This paper described the simulation of an optimal autonomous network dispatching in day ahead markets, based on predicted spot prices for real power, and two ancillary services. It was concluded that large changes occur in a power systems structure and operation, most of them adding to the uncertainty and complexity of the system. The introduced concept of an autonomous power network-based power system was shown to be a realistic and consistent approach to formulate and operate a market-based dispatch of both power and ancillary services. 9 refs., 4 figs

Quark model and equivalent local potential

International Nuclear Information System (INIS)

Takeuchi, Sachiko; Shimizu, Kiyotaka

2002-01-01

In this paper, we investigate the short-range repulsion given by the quark cluster model employing an inverse scattering problem. We find that the local potential which reproduces the same phase shifts as those given by the quark cluster model has a strong repulsion at short distances in the NN 1 S 0 channel. There, however, appears an attractive pocket at very short distances due to a rather weak repulsive behavior at very high energy. This repulsion-attractive-pocket structure becomes more manifest in the channel which has an almost forbidden state, ΣN(T=3/2) 3 S 1 . In order to see what kinds of effects are important to reproduce the short-range repulsion in the quark cluster model, we investigate the contribution coming from the one-gluon-exchange potential and the normalization separately. It is clarified that the gluon exchange constructs the short-range repulsion in the NN 1 S 0 while the quark Pauli-blocking effect governs the feature of the repulsive behavior in the ΣN(T=3/2) 3 S 1 channel

Wilson and Gisvold's textbook of organic medicinal and pharmaceutical chemistry

National Research Council Canada - National Science Library

Wilson, Charles Owens; Beale, John Marlowe; Block, John H

2011-01-01

... and chemistry students as well as practicing pharmacists. Fully updated for the Twelfth Edition, the book begins with the fundamental principles of chemistry, biochemistry, and biology that underlie the discipline of medicinal chemistry...

An Enhanced Islanding Microgrid Reactive Power, Imbalance Power, and Harmonic Power Sharing Scheme

DEFF Research Database (Denmark)

He, Jinwei; Lin, Yun Wei; Blaabjerg, Frede

2015-01-01

To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through online virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power, or harmonic power is added to the conventional real power...

Electric power system / emergency power supply

International Nuclear Information System (INIS)

Dorn, P.G.

1980-01-01

One factor of reliability of reactor safety systems is the integrity of the power supply. The purpose of this paper is a review and a discussion of the safety objectives required for the planning, licensing, manufacture and erection of electrical power systems and components. The safety aspects and the technical background of the systems for - the electric auxiliary power supply system and - the emergency power supply system are outlined. These requirements result specially from the safety standards which are the framework for the studies of safety analysis. The overall and specific requirements for the electrical power supply of the safety systems are demonstrated on a 1300 MW standard nuclear power station with a pressurized water reactor. (orig.)

Wind power in modern power systems

DEFF Research Database (Denmark)

Chen, Zhe

2013-01-01

In recent years, wind power is experiencing a rapid growth, and large-scale wind turbines/wind farms have been developed and connected to power systems. However, the traditional power system generation units are centralized located synchronous generators with different characteristics compared...... with wind turbines. This paper presents an overview of the issues about integrating large-scale wind power plants into modern power systems. Firstly, grid codes are introduced. Then, the main technical problems and challenges are presented. Finally, some possible technical solutions are discussed....

Stockholm Power Tech. Power systems

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-11-01

The proceedings from this symposium is presented in six volumes: Invited speakers` sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

Stockholm Power Tech. Power systems

International Nuclear Information System (INIS)

1995-01-01

The proceedings from this symposium is presented in six volumes: Invited speakers' sessions; Power systems; Power electronics; High-voltage technology; Electrical machines and drives; and Information and control systems. This report covers the power systems volume. Separate abstracts have been prepared for 141 of the 145 papers in this volume

Status of LAMPF

International Nuclear Information System (INIS)

Rosen, L.

1979-01-01

Crucial aspects of the LAMPF operation and its scientific programs during 1978 are discussed and evaluated. This report is from a talk given at the Twelfth LAMPF Users Meeting, Novermber 13 and 14, 1978

A MEMS electret generator with electrostatic levitation for vibration-driven energy-harvesting applications

International Nuclear Information System (INIS)

Suzuki, Yuji; Miki, Daigo; Edamoto, Masato; Honzumi, Makoto

2010-01-01

In this paper, we propose a passive gap-spacing control method in order to avoid stiction between top and bottom structures in in-plane sensor/actuator/generator applications. A patterned electret using a high-performance perfluoro polymer material is employed to induce a repulsive electrostatic force. An out-of-plane repulsive force is successfully demonstrated with our early prototype, in both air and liquid. By using the present electret-based levitation method to keep the air gap, a MEMS electret generator has been developed for energy-harvesting applications. A dual-phase electrode arrangement is adopted in order to reduce the horizontal electrostatic damping force. With the present prototype, about 0.5 µW is obtained for both phases of the generator, resulting in a total power output of 1.0 µW at an acceleration of 2 g with 63 Hz. With our electromechanical model of the generator, we have confirmed that the model can mimic the response of the generator prototype

Transverse momentum distribution in the Nielsen-Olesen model

Energy Technology Data Exchange (ETDEWEB)

Sakai, S [Tokyo Univ. of Education (Japan). Dept. of Physics

1976-05-01

The power dependence in the inclusive ksub(T)-distribution in the large ksub(T)-region is derived in the extended hadron model of Nielsen and Olesen without relying upon hard scattering of hadron constituents. The ksub(T)-dependence behaves like -- -ln ksub(T) when ksub(T) is small, then it becomes exp(-..gamma..ksub(T)) in the medium ksub(T) region (ksub(T)<=1.5(GeV/c)), and further it changes to behave like (ksub(T))sup(-n(ksub(T)), when ksub(T) becomes much larger. Our ksub(T)-dependence is consistent with the experimental data. This ksub(T)-distribution is derived by the strong repulsive force between two vortex lines (identified as hadron). This repulsive force is caused by the pressure of the spontaneously broken vacuum state which is necessary to confine the vector field. Our model on the ksub(T)-distribution is very analogous to the production of massive resonances and their successive decay.

Thermodynamic curvature of soft-sphere fluids and solids

Science.gov (United States)

Brańka, A. C.; Pieprzyk, S.; Heyes, D. M.

2018-02-01

The influence of the strength of repulsion between particles on the thermodynamic curvature scalar R for the fluid and solid states is investigated for particles interacting with the inverse power (r-n) potential, where r is the pair separation and 1 /n is the softness. Exact results are obtained for R in certain limiting cases, and the R behavior determined for the systems in the fluid and solid phases. It is found that in such systems the thermodynamic curvature can be positive for very soft particles, negative for steeply repulsive (or large n ) particles across almost the entire density range, and can change sign between negative and positive at a certain density. The relationship between R and the form of the interaction potential is more complex than previously suggested, and it may be that R is an indicator of the relative importance of energy and entropy contributions to the thermodynamic properties of the system.

Thermoelectric power generator for variable thermal power source

Science.gov (United States)

Bell, Lon E; Crane, Douglas Todd

2015-04-14

Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Emergency power systems at nuclear power plants

International Nuclear Information System (INIS)

1982-01-01

This Guide applies to nuclear power plants for which the total power supply comprises normal power supply (which is electric) and emergency power supply (which may be electric or a combination of electric and non-electric). In its present form the Guide provides general guidance for all types of emergency power systems (EPS) - electric and non-electric, and specific guidance (see Appendix A) on the design principles and the features of the emergency electric power system (EEPS). Future editions will include a second appendix giving specific guidance on non-electric power systems. Section 3 of this Safety Guide covers information on considerations that should be taken into account relative to the electric grid, the transmission lines, the on-site electrical supply system, and other alternative power sources, in order to provide high overall reliability of the power supply to the EPS. Since the nuclear power plant operator does not usually control off-site facilities, the discussion of methods of improving off-site reliability does not include requirements for facilities not under the operator's control. Sections 4 to 11 of this Guide provide information, recommendations and requirements that would apply to any emergency power system, be it electric or non-electric

ITER EDA newsletter. V. 9, no. 6

International Nuclear Information System (INIS)

2000-06-01

This newsletter contains the reports of the twelfth meeting of the ITER physics expert group on diagnostics and the 14. international conference on plasma-surface interactions in controlled fusion devices. Individual abstracts have been prepared

Power Burst Facility: power oscillation problem

International Nuclear Information System (INIS)

Lussie, W.G.; Wadkins, R.P.; Wells, R.A.

1975-01-01

In late 1973 PBF achieved a power level of 15 MW. During this period of operation fluctuations in reactor power were observed. Many possible causes of these fluctuations were considered and a number of nuclear and non-nuclear tests were conducted. Initial instrumentation installed in the core showed coolant outlet temperature variations of 10 0 F for several fuel cannisters and approximately 10 percent power variations at 15 MW. Power spectral density analysis showed a predominant frequency of 0.05 to 0.06 HZ. The testing program to determine the cause of the power oscillations is described

A means to a cleaner environment: energy efficient platinum-containing fuel cells to be introduced commercially in the early 1990s

Energy Technology Data Exchange (ETDEWEB)

Anon,

1991-01-01

The twelfth National Fuel Cell Seminar held in Phoenix, Arizona, U.S.A. from 26th to 28th November 1990, was attended by 450 delegates from 17 countries, representing both developers and potential users worldwide. ''Fuel Cells - An Answer to a Cleaner Environment'' was the key theme running throughout the conference. This was strongly linked to the firm belief that fuel cells would make an important contribution to the world's energy needs over the next ten years as economically viable fuel cell power plants become commercialised. The conference heard that platinum containing phosphoric acid fuel cells (PAFC) are soon to be produced on a commercial basis. Both Fuji and Toshiba announced that they had opened PAFC production facilities in Japan during 1990. The key progress regarding development of Proton Exchange Membrane Fuel Cells (PEMFC) was the announcement of a U.S. Government sponsored programme, to be led to General Motors, to produce a PEMFC powered motor vehicle. The conference reflected the growing extent of the multi-national collaborations that are now underway to develop fuel cell technologies. (author).

A RWMAC commentary on the Science Policy Research Unit report: UK nuclear decommissioning policy: time for decision

International Nuclear Information System (INIS)

1994-04-01

Chapter 4 of the RWMAC's Twelfth Annual Report discussed nuclear power plant decommissioning strategy. One of the RWMAC's conclusions was that the concept of financial provisioning for power station decommissioning liabilities, which might be passed on to society several generations into the future, deserved further study. A specification for such a study was duly written (Annex 2) and, following consideration of tendered responses, the Science Policy Research Unit (SPRU) at Sussex University, was contracted to carry out the work. The SPRU report stands as a SPRU analysis of the subject. This separate short RWMAC report, which is being released at the same time as the SPRU report, presents the RWMAC's own commentary on the SPRU study. The RWMAC has identified five main issues which should be addressed when deciding on a nuclear plant decommissioning strategy. These are: the technical approach to decommissioning, the basis of financial provisions, treatment of risk, segregation of management of funds, and the need for a wider environmental view. These issues are addressed in this RWMAC report. (author)

Coal: a human history

Energy Technology Data Exchange (ETDEWEB)

Freese, B.

2002-12-01

Prized as 'the best stone in Britain' by Roman invaders who carved jewellery out of it, coal has transformed societies, powered navies, fueled economies, and expanded frontiers. It made China a twelfth-century superpower, inspired the writing of the Communist Manifesto, and helped the northern states win the American Civil War. Yet the mundane mineral that built our global economy - and even today powers our electrical plants - has also caused death, disease, and environmental destruction. As early as 1306, King Edward I tried to ban coal (unsuccessfully) because its smoke became so obnoxious. Its recent identification as a primary cause of global warming has made it a cause celebre of a new kind. In this book, Barbara Freese takes us on an historical journey that begins three hundred million years ago and spans the globe. From the 'Great Stinking Fogs' of London to the rat-infested coal mines of Pennsylvania, from the impoverished slums of Manchester to the toxic city streets of Beijing, this book describes an ordinary substance that has done extraordinary things.

PowerFactory applications for power system analysis

CERN Document Server

Gonzalez-Longatt, Francisco

2014-01-01

This book presents a comprehensive set of guidelines and applications of DIgSILENT PowerFactory, an advanced power system simulation software package, for different types of power systems studies. Written by specialists in the field, it combines expertise and years of experience in the use of DIgSILENT PowerFactory with a deep understanding of power systems analysis. These complementary approaches therefore provide a fresh perspective on how to model, simulate and analyse power systems. It presents methodological approaches for modelling of system components, including both classical and non-

Cost of nuclear power generation judged by power rate

International Nuclear Information System (INIS)

Hirai, Takaharu

1981-01-01

According to estimation guidance, power rates in general are the proper cost plus the specific compensation and adjustment addition. However, the current system of power rates is of power-source development promotion type involving its tax. The structure of power rate determination must be restudied now especially in connection of nuclear power generation. The cost of nuclear power generation as viewed from power rate is discussed as follows: the fear of military application of power plants, rising plant construction costs, the loophole in fuel cost calculation, unreasonable unit power cost, depreciation and repair cost, business compensation, undue business compensation in nuclear power, the costs of nuclear waste management, doubt concerning nuclear power cost, personnel, pumping-up and power transmission costs in nuclear power, energy balance analysis, nuclear power viewed in entropy, the suppression of power consumption. (J.P.N.)

An accurate autonomous islanding microgrid reactive power, imbalance power and harmonic power sharing scheme

DEFF Research Database (Denmark)

He, Jinwei; Li, Yun Wei; Blaabjerg, Frede

2013-01-01

To address inaccurate power sharing problems in autonomous islanding microgrids, an enhanced droop control method through adaptive virtual impedance adjustment is proposed. First, a term associated with DG reactive power, imbalance power or harmonic power is added to the conventional real power...

Smart Power Supply for Battery-Powered Systems

Science.gov (United States)

Krasowski, Michael J.; Greer, Lawrence; Prokop, Norman F.; Flatico, Joseph M.

2010-01-01

A power supply for battery-powered systems has been designed with an embedded controller that is capable of monitoring and maintaining batteries, charging hardware, while maintaining output power. The power supply is primarily designed for rovers and other remote science and engineering vehicles, but it can be used in any battery alone, or battery and charging source applications. The supply can function autonomously, or can be connected to a host processor through a serial communications link. It can be programmed a priori or on the fly to return current and voltage readings to a host. It has two output power busses: a constant 24-V direct current nominal bus, and a programmable bus for output from approximately 24 up to approximately 50 V. The programmable bus voltage level, and its output power limit, can be changed on the fly as well. The power supply also offers options to reduce the programmable bus to 24 V when the set power limit is reached, limiting output power in the case of a system fault detected in the system. The smart power supply is based on an embedded 8051-type single-chip microcontroller. This choice was made in that a credible progression to flight (radiation hard, high reliability) can be assumed as many 8051 processors or gate arrays capable of accepting 8051-type core presently exist and will continue to do so for some time. To solve the problem of centralized control, this innovation moves an embedded microcontroller to the power supply and assigns it the task of overseeing the operation and charging of the power supply assets. This embedded processor is connected to the application central processor via a serial data link such that the central processor can request updates of various parameters within the supply, such as battery current, bus voltage, remaining power in battery estimations, etc. This supply has a direct connection to the battery bus for common (quiescent) power application. Because components from multiple vendors may have

77 FR 46044 - Steel Wire Garment Hangers From the Socialist Republic of Vietnam: Preliminary Determination of...

Science.gov (United States)

2012-08-02

... NME country, section 773(c)(1) of the Act directs it to base NV, in most circumstances, on the NME...); Certain Pasta from Italy: Notice of Final Results of the Twelfth Administrative Review, 75 FR 6352...

L'expression orale apres treize ans d'immersion francaise (Oral Expression After Thirteen Years of French Immersion).

Science.gov (United States)

Pellerin, Micheline; Hammerly, Hector

1986-01-01

Conversations with six twelfth graders who had been in French immersion since kindergarten found a high rate of incorrect sentences, suggesting a faulty interlanguage fossilized at grade six and a need for immersion program revision. (MSE)

Effect of the integrated approach of yoga therapy on platelet count and uric acid in pregnancy: A multicenter stratified randomized single-blind study

Directory of Open Access Journals (Sweden)

R Jayashree

2013-01-01

Conclusion: Antenatal integrated yoga from the twelfth week is safe and effective in promoting a healthy progression of platelets and uric acid in women with high-risk pregnancy, pointing to healthy hemodilution and better physiological adaptation.

Compensating active power imbalances in power system with large-scale wind power penetration

DEFF Research Database (Denmark)

Basit, Abdul; Hansen, Anca Daniela; Altin, Müfit

2016-01-01

Large-scale wind power penetration can affectthe supply continuity in the power system. This is a matterof high priority to investigate, as more regulating reservesand specified control strategies for generation control arerequired in the future power system with even more highwind power penetrat...

Military power requirements and backup power considerations

International Nuclear Information System (INIS)

Botts, T.E.

1986-01-01

All US Air Force (USAF) facilities have certain critical power requirements that must be met in order to carry out their mission successfully. Internal USAF studies have shown that the mission can degrade precipitously as the available power decreases below the mission critical level. Now, more than ever before, the military and private industry are finding that certain functions, such as automated data processing and automated process control, respond catastrophically to power reductions. Furthermore, increased reliance on electrical power means, in the case of the Air Force, that critical power requirements are anticipated to increase by half over the next 15 yr. For these reasons and others, the USAF is investigating several means of improving the availability of electric power under adverse conditions above that which can be provided by an off-base supplier. Among the approaches to this problem being pursued at this time are a program to improve all sorts of generator sets on a service-wide basis and the Multimegawatt Terrestrial Power (MTP) Program, which is pursuing the design and testing of a small dedicated nuclear power source to provide critical mission power. The purpose of this paper is to provide some insight into some of the issues associated with USAF power programs

Real-time impact of power balancing on power system operation with large scale integration of wind power

DEFF Research Database (Denmark)

Basit, Abdul; Hansen, Anca Daniela; Sørensen, Poul Ejnar

2017-01-01

Highly wind power integrated power system requires continuous active power regulation to tackle the power imbalances resulting from the wind power forecast errors. The active power balance is maintained in real-time with the automatic generation control and also from the control room, where...... power system model. The power system model takes the hour-ahead regulating power plan from power balancing model and the generation and power exchange capacities for the year 2020 into account. The real-time impact of power balancing in a highly wind power integrated power system is assessed...

Hybrid wind power balance control strategy using thermal power, hydro power and flow batteries

OpenAIRE

Gelažanskas, Linas; Baranauskas, Audrius; Gamage, Kelum A.A.; Ažubalis, Mindaugas

2016-01-01

The increased number of renewable power plants pose threat to power system balance. Their intermittent nature makes it very difficult to predict power output, thus either additional reserve power plants or new storage and control technologies are required. Traditional spinning reserve cannot fully compensate sudden changes in renewable energy power generation. Using new storage technologies such as flow batteries, it is feasible to balance the variations in power and voltage within very short...

Power manager and method for managing power

NARCIS (Netherlands)

Burchard, A.T.; Kersten, G.; Molnos, A.M.; Milutinovic, A.; Goossens, K.G.W.; Steffens, E.F.M.

2009-01-01

A power manager (106) and method for managing the power supplied to an electronic device is provided. Furthermore, a system wherein the power supplied to an electronic device is managed is provided. The power manager (106) is operative to monitor a hardware monitor (104) during a monitoring time

Wireless powering for low-power distributed sensors

Directory of Open Access Journals (Sweden)

Popović Zoya B.

2006-01-01

Full Text Available In this paper, an overview of the field of wireless powering is presented with an emphasis on low-power applications. Several rectenna elements and arrays are discussed in more detail: (1 a 10-GHz array for powering sensors in aircraft wings; (2 a single antenna in the 2.4-GHz ISM band for low-power assisted-living sensors; and (3 a broadband array for power harvesting in the 2-18GHz frequency range.

Impacts of Wind Power on Power System Stability

NARCIS (Netherlands)

Vittal, E.; Keane, A.; Slootweg, J.G.; Kling, W.L.; Ackermann, T.

2012-01-01

This chapter examines how wind power will impact the stability of power systems. It focuses on the three aspects of power system stability: voltage stability, rotor angle stability and frequency stability. It completes a detailed analysis as to how wind power in power systems will impact the

Chickenpox and Shingles Tests

Science.gov (United States)

... Wu, A. (© 2006). Tietz Clinical Guide to Laboratory Tests , Fourth Edition: Saunders Elsevier, St. Louis, MO. Pp 1623. Forbes, B. et. al. (© 2007). Bailey & Scott's Diagnostic Microbiology , Twelfth Edition: Mosby Elsevier Press, St. Louis, MO. ...

Nuclear power/water pumping-up composite power plant

International Nuclear Information System (INIS)

Okamura, Kiyoshi.

1995-01-01

In a nuclear power/water pumping-up composite power plant, a reversible pump for pumping-up power generation connected to a steam turbine is connected to an upper water reservoir and a lower water reservoir. A pumping-up steam turbine for driving the turbine power generator, a hydraulic pump for driving water power generator by water flowing from the upper water reservoir and a steam turbine for driving the pumping-up pump by steams from a nuclear reactor are disposed. When power demand is small during night, the steam turbine is rotated by steams of the reactor, to pump up the water in the lower water reservoir to the upper water reservoir by the reversible pump. Upon peak of power demand during day time, power is generated by the steams of the reactor, as well as the reversible pump is rotated by the flowing water from the upper water reservoir to conduct hydraulic power generation. Alternatively, hydraulic power generation is conducted by flowing water from the upper reservoir. Since the number of energy conversion steps in the combination of nuclear power generation and pumping-up power generation is reduced, energy loss is reduced and utilization efficiency can be improved. (N.H.)

Comprehensive Power Losses Model for Electronic Power Transformer

DEFF Research Database (Denmark)

Yue, Quanyou; Li, Canbing; Cao, Yijia

2018-01-01

and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self-losses......The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...

Comprehensive Power Losses Model for Electronic Power Transformer

DEFF Research Database (Denmark)

Yue, Quanyou; Li, Canbing; Cao, Yijia

2018-01-01

The electronic power transformer (EPT) has highe rpower losses than the conventional transformer. However, the EPT can correct the power factor, compensate the unbalanced current and reduce the line power losses in the distribution network.Therefore, the higher losses of the EPT and the consequent...... reduced power losses in the distribution network require a comprehensive consideration when comparing the power losses of theEPT and conventional transformer. In this paper, a comprehensive power losses analysis model for the EPT in distribution networks is proposed. By analyzing the EPT self......-losses and considering the impact of the non-unity power factor and the three-phase unbalanced current, the overall power losses in the distribution network when using the EPT to replace the conventional transformer is analyzed, and the conditions in which the application of the EPT can cause less power losses...

Selectivity of power system protections at power swings in power system

Directory of Open Access Journals (Sweden)

Jan Machowski

2012-12-01

Full Text Available The paper discusses out-of-step protection systems such as: generator pole slip protections, out of step tripping protections, distance protections of step-up transformer, distance protections of transmission lines and transformers, power swing blocking, and special out-of-step protection. It is shown that all these protections make up a protection system, to which a setting concept uniform for the entire power system has to be applied. If a power system is inappropriately equipped with these protections, or their settings are inappropriate, they may operate unselectively, thus contributing to the development of power system blackouts. In the paper the concepts for a real power system are given for the two stages: target stage fully compliant with selectivity criteria, and transitional stage between the current and target stages.

Power Ramp Limitation capabilities of Large PV Power Plants with Active Power Reserves

DEFF Research Database (Denmark)

Bogdan, Craciun; Kerekes, Tamas; Sera, Dezso

2017-01-01

Power Ramp Limitation (PRL) is likely to become a requirement for large scale photovoltaic power plants (LPVPPs) in order to allow the increase of PV penetration levels. Especially in islands with reduced inertia capability, this problem is more stringent: high power ramp can be caused by either...... fast irradiance changes or other participant generators for example wind power, or loads. In order to compensate for the power mismatch, LPVPPs must use Active Power Reserve (APR), by either curtailment or auxiliary storage. The paper proposes a PRL control structure for dynamic APR sizing...... and deployment. The selected test case is the power system of Puerto Rico (PREPA), modeled using the modified IEEE 12 bus benchmark system, with different levels of PV penetration. It is shown that LPVPP with PRL can effectively reduce the ramping rate of the participating generators. Considering that the large...

Wind power integration into the automatic generation control of power systems with large-scale wind power

Directory of Open Access Journals (Sweden)

Abdul Basit

2014-10-01

Full Text Available Transmission system operators have an increased interest in the active participation of wind power plants (WPP in the power balance control of power systems with large wind power penetration. The emphasis in this study is on the integration of WPPs into the automatic generation control (AGC of the power system. The present paper proposes a coordinated control strategy for the AGC between combined heat and power plants (CHPs and WPPs to enhance the security and the reliability of a power system operation in the case of a large wind power penetration. The proposed strategy, described and exemplified for the future Danish power system, takes the hour-ahead regulating power plan for generation and power exchange with neighbouring power systems into account. The performance of the proposed strategy for coordinated secondary control is assessed and discussed by means of simulations for different possible future scenarios, when wind power production in the power system is high and conventional production from CHPs is at a minimum level. The investigation results of the proposed control strategy have shown that the WPPs can actively help the AGC, and reduce the real-time power imbalance in the power system, by down regulating their production when CHPs are unable to provide the required response.

Predictive Value of Glasgow Coma Score and Full Outline of Unresponsiveness Score on the Outcome of Multiple Trauma Patients.

Science.gov (United States)

Baratloo, Alireza; Shokravi, Masumeh; Safari, Saeed; Aziz, Awat Kamal

2016-03-01

The Full Outline of Unresponsiveness (FOUR) score was developed to compensate for the limitations of Glasgow coma score (GCS) in recent years. This study aimed to assess the predictive value of GCS and FOUR score on the outcome of multiple trauma patients admitted to the emergency department. The present prospective cross-sectional study was conducted on multiple trauma patients admitted to the emergency department. GCS and FOUR scores were evaluated at the time of admission and at the sixth and twelfth hours after admission. Then the receiver operating characteristic (ROC) curve, sensitivity, specificity, as well as positive and negative predictive value of GCS and FOUR score were evaluated to predict patients' outcome. Patients' outcome was divided into discharge with and without a medical injury (motor deficit, coma or death). Finally, 89 patients were studied. Sensitivity and specificity of GCS in predicting adverse outcome (motor deficit, coma or death) were 84.2% and 88.6% at the time of admission, 89.5% and 95.4% at the sixth hour and 89.5% and 91.5% at the twelfth hour, respectively. These values for the FOUR score were 86.9% and 88.4% at the time of admission, 89.5% and 100% at the sixth hour and 89.5% and 94.4% at the twelfth hour, respectively. Findings of this study indicate that the predictive value of FOUR score and GCS on the outcome of multiple trauma patients admitted to the emergency department is similar.

Wind power integration into the automatic generation control of power systems with large-scale wind power

DEFF Research Database (Denmark)

Basit, Abdul; Hansen, Anca Daniela; Altin, Müfit

2014-01-01

Transmission system operators have an increased interest in the active participation of wind power plants (WPP) in the power balance control of power systems with large wind power penetration. The emphasis in this study is on the integration of WPPs into the automatic generation control (AGC......) of the power system. The present paper proposes a coordinated control strategy for the AGC between combined heat and power plants (CHPs) and WPPs to enhance the security and the reliability of a power system operation in the case of a large wind power penetration. The proposed strategy, described...... and exemplified for the future Danish power system, takes the hour-ahead regulating power plan for generation and power exchange with neighbouring power systems into account. The performance of the proposed strategy for coordinated secondary control is assessed and discussed by means of simulations for different...

A Review of Power Electronics for Wind Power

Institute of Scientific and Technical Information of China (English)

Zhe CHEN

2011-01-01

The paper reviews the power electronic applications for wind energy systems.Main wind turbine systems with different generators and power electronic converters are described.The electrical topologies of wind farms with power electronic conversion are discussed.Power electronic applications for improving the performance of wind turbines and wind farms in power systems have been illustrated.

Power

DEFF Research Database (Denmark)

Elmholdt, Claus Westergård; Fogsgaard, Morten

2016-01-01

and creativity suggests that when managers give people the opportunity to gain power and explicate that there is reason to be more creative, people will show a boost in creative behaviour. Moreover, this process works best in unstable power hierarchies, which implies that power is treated as a negotiable....... It is thus a central point that power is not necessarily something that breaks down and represses. On the contrary, an explicit focus on the dynamics of power in relation to creativity can be productive for the organisation. Our main focus is to elaborate the implications of this for practice and theory...

Dynamic influences of wind power on the power system

Energy Technology Data Exchange (ETDEWEB)

Rosas, Pedro

2003-03-01

The thesis first presents the basics influences of wind power on the power system stability and quality by pointing out the main power quality issues of wind power in a small-scale case and following, the expected large-scale problems are introduced. Secondly, a dynamic wind turbine model that supports power quality assessment of wind turbines is presented. Thirdly, an aggregate wind farm model that support power quality and stability analysis from large wind farms is presented. The aggregate wind farm model includes the smoothing of the relative power fluctuation from a wind farm compared to a single wind turbine. Finally, applications of the aggregate wind farm model to the power systems are presented. The power quality and stability characteristics influenced by large-scale wind power are illustrated with three cases. In this thesis, special emphasis has been given to appropriate models to represent the wind acting on wind farms. The wind speed model to a single wind turbine includes turbulence and tower shadow effects from the wind and the rotational sampling turbulence due to the rotation of the blades. In a park scale, the wind speed model to the wind farm includes the spatial coherence between different wind turbines. Here the wind speed model is applied to a constant rotational speed wind turbine/farm, but the model is suitable to variable speed wind turbine/farm as well. The cases presented here illustrate the influences of the wind power on the power system quality and stability. The flicker and frequency deviations are the main power quality parameters presented. The power system stability concentrates on the voltage stability and on the power system oscillations. From the cases studied, voltage and the frequency variations were smaller than expected from the large-scale wind power integration due to the low spatial correlation of the wind speed. The voltage quality analysed in a Brazilian power system and in the Nordel power system from connecting large

AC Power Local Network with Multiple Power Routers

Directory of Open Access Journals (Sweden)

Ryo Takahashi

2013-12-01

Full Text Available Controlling power flow and achieving appropriate matching between power sources and loads according to the quality of energy is expected to be one of the approaches to reduce wasted energy consumption. A power router, proposed recently, has the capability of realizing circuit switching in a power distribution network. This study focuses on the feasibility of an AC power routing network system composed of multiple power routers. To evaluate the feasibility, we experimentally confirm the circuit switching operation of the parallel and series configurations of the power routers, so that the network system can be designed by the combination of parallel and series configurations.

Phase Coexistence in Two-Dimensional Passive and Active Dumbbell Systems

Science.gov (United States)

Cugliandolo, Leticia F.; Digregorio, Pasquale; Gonnella, Giuseppe; Suma, Antonio

2017-12-01

We demonstrate that there is a macroscopic coexistence between regions with hexatic order and regions in the liquid or gas phase over a finite interval of packing fractions in active dumbbell systems with repulsive power-law interactions in two dimensions. In the passive limit, this interval remains finite, similar to what has been found in two-dimensional systems of hard and soft disks. We did not find discontinuous behavior upon increasing activity from the passive limit.

Maps for the future.

Directory of Open Access Journals (Sweden)

Cristina D’Alessandro-Scarpari

2005-05-01

Full Text Available Geographers’ relations with maps have a long story of attraction and repulsion. The map has always fascinated Geographers (even before the institutionalization of the discipline as a powerful tool, able to demarcate territories, to produce different visions of them and to transform them by the actions they may cause or influence. Sometimes for strategic reasons Geographers have also denigrated cartography as a secondary and technical form of knowledge, a tool merely for understanding and ...

Similarities and differences between conventional power and nuclear power

International Nuclear Information System (INIS)

Wang Yingrong

2011-01-01

As the implementation of the national guideline of 'proactively promoting nuclear power development', especially after China decided in 2006 to introduce Westinghouse's AP1000 technology, some of the power groups specialized in conventional power generation, have been participating in the preliminary work and construction of nuclear power projects in certain degrees. Meanwhile, such traditional nuclear power corporations as China National Nuclear Corporation (CNNC) and China Guangdong Nuclear Power Corporation (CGNPC) have also employed some employees with conventional power generation experience. How can these employees who have long been engaged in conventional power generation successfully adapt to the new work pattern, ideology, knowledge, thinking mode and proficiency of nuclear power, so that they can fit in with the work requirements of nuclear power and become qualified as soon as possible? By analyzing the technological, managerial and cultural features of nuclear power, as well as some issues to be kept in mind when engaged in nuclear power, this paper intends to make some contribution to the nuclear power development in the specific period. (author)

Critical thinking skills profile of high school students in learning chemistry

Directory of Open Access Journals (Sweden)

Budi Utami

2017-08-01

Full Text Available Critical thinking skill is the priority in the goals of education. In this case, the critical thinking has the higher process, such as analyzing, synthesizing, evaluating, drawing conclusion and reflecting which enables the individual to make the reasonable assessment both in the classroom and in the daily life.  This research is aimed to determine the students’ critical thinking skill in learning Chemistry at senior high school. This research used descriptive method in which the instruments were developed based on the indicators of critical thinking skill. The population of this research was 100 students of tenth, eleventh and twelfth grade from senior high schools in Surakarta which was chosen using cluster random sampling technique. The result of the research shows that the students of tenth, eleventh and twelfth grade have adequate critical thinking skills.

Balancing modern Power System with large scale of wind power

DEFF Research Database (Denmark)

Basit, Abdul; Altin, Müfit; Hansen, Anca Daniela

2014-01-01

Power system operators must ensure robust, secure and reliable power system operation even with a large scale integration of wind power. Electricity generated from the intermittent wind in large propor-tion may impact on the control of power system balance and thus deviations in the power system...... frequency in small or islanded power systems or tie line power flows in interconnected power systems. Therefore, the large scale integration of wind power into the power system strongly concerns the secure and stable grid operation. To ensure the stable power system operation, the evolving power system has...... to be analysed with improved analytical tools and techniques. This paper proposes techniques for the active power balance control in future power systems with the large scale wind power integration, where power balancing model provides the hour-ahead dispatch plan with reduced planning horizon and the real time...

Pragmatic power

CERN Document Server

Eccles, William

2008-01-01

Pragmatic Power is focused on just three aspects of the AC electrical power system that supplies and moves the vast majority of electrical energy nearly everywhere in the world: three-phase power systems, transformers, and induction motors. The reader needs to have had an introduction to electrical circuits and AC power, although the text begins with a review of the basics of AC power. Balanced three-phase systems are studied by developing their single-phase equivalents. The study includes a look at how the cost of ""power"" is affected by reactive power and power factor. Transformers are cons

Power System Operation with Large Scale Wind Power Integration

DEFF Research Database (Denmark)

Suwannarat, A.; Bak-Jensen, B.; Chen, Z.

2007-01-01

to the uncertain nature of wind power. In this paper, proposed models of generations and control system are presented which analyze the deviation of power exchange at the western Danish-German border, taking into account the fluctuating nature of wind power. The performance of the secondary control of the thermal......The Danish power system starts to face problems of integrating thousands megawatts of wind power, which produce in a stochastic behavior due to natural wind fluctuations. With wind power capacities increasing, the Danish Transmission System Operator (TSO) is faced with new challenges related...... power plants and the spinning reserves control from the Combined Heat and Power (CHP) units to achieve active power balance with the increased wind power penetration is presented....

Investigating power control in autonomous power systems with increasing wind power penetration

Energy Technology Data Exchange (ETDEWEB)

Margaris, Ioannis D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Hansen, Anca D.; Sorensen, Poul [Risoe National Laboratory, Roskilde (Denmark). Wind Energy Dept.; Hatziargyriou, Nikos D. [National Technical Univ. of Athens (Greece). Electric Energy Systems Lab.; Public Power Corporation S.A., Athens (Greece)

2009-07-01

Increasing levels of wind penetration in autonomous power systems has set intensively high standards with respect to wind turbine technology during the last years. Special features of non-interconnected power systems make security issues rather critical, as the operation of large wind farms like conventional power plants is becoming a necessity. This paper includes the study case of Rhodos island, in Greece, where rapidly increasing wind penetration has started to impose serious security issues for the immediate future. The scenarios studied here correspond to reference year of study 2012 and include wind farms with three different wind turbine technologies - namely Doubly Fed Induction Generator (DFIG), Permanent Magnet Synchronous Generator (PMSG) and Active Stall Induction Generator (ASIG) based wind turbines. Aggregated models of the wind farms are being used and results for different load cases are being analyzed and discussed. The ability of wind farms to assist in some of the power system control services traditionally carried out by conventional synchronous generation is being investigated and discussed. The power grid of the island, including speed governors and automatic voltage regulators, is simulated in the dedicated power system simulation program Power Factory from DIgSILENT. (orig.)

Sexual aggression when power is new: Effects of acute high power on chronically low-power individuals.

Science.gov (United States)

Williams, Melissa J; Gruenfeld, Deborah H; Guillory, Lucia E

2017-02-01

Previous theorists have characterized sexually aggressive behavior as an expression of power, yet evidence that power causes sexual aggression is mixed. We hypothesize that power can indeed create opportunities for sexual aggression-but that it is those who chronically experience low power who will choose to exploit such opportunities. Here, low-power men placed in a high-power role showed the most hostility in response to a denied opportunity with an attractive woman (Studies 1 and 2). Chronically low-power men and women given acute power were the most likely to say they would inappropriately pursue an unrequited workplace attraction (Studies 3 and 4). Finally, having power over an attractive woman increased harassment behavior among men with chronic low, but not high, power (Study 5). People who see themselves as chronically denied power appear to have a stronger desire to feel powerful and are more likely to use sexual aggression toward that end. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Power system stabilizer control for wind power to enhance power system stability

OpenAIRE

Domínguez García, José Luís; Gomis Bellmunt, Oriol; Bianchi, Fernando Daniel; Sumper, Andreas

2011-01-01

The paper presents a small signal stability analysis for power systems with wind farm interaction. Power systems have damping oscillation modes that can be excited by disturbance or fault in the grid. The power converters of the wind farms can be used to reduce these oscillations and make the system more stable. These ideas are explored to design a power system stabilized (PSS) for a network with conventional generators and a wind farm in order to increase the damping of the oscillation...

Wind farm - A power source in future power systems

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede

2009-01-01

wind turbines and wind farms, and then introduces the wind power development and wind farms. An optimization platform for designing electrical systems of offshore wind farms is briefed. The major issues related to the grid connection requirements and the operation of wind turbines/farms in power......The paper describes modern wind power systems, introduces the issues of large penetration of wind power into power systems, and discusses the possible methods of making wind turbines/farms act as a power source, like conventional power plants in power systems. Firstly, the paper describes modern...... systems are illustrated....

Low Power Design with High-Level Power Estimation and Power-Aware Synthesis

CERN Document Server

Ahuja, Sumit; Shukla, Sandeep Kumar

2012-01-01

Low-power ASIC/FPGA based designs are important due to the need for extended battery life, reduced form factor, and lower packaging and cooling costs for electronic devices. These products require fast turnaround time because of the increasing demand for handheld electronic devices such as cell-phones, PDAs and high performance machines for data centers. To achieve short time to market, design flows must facilitate a much shortened time-to-product requirement. High-level modeling, architectural exploration and direct synthesis of design from high level description enable this design process. This book presents novel research techniques, algorithms,methodologies and experimental results for high level power estimation and power aware high-level synthesis. Readers will learn to apply such techniques to enable design flows resulting in shorter time to market and successful low power ASIC/FPGA design. Integrates power estimation and reduction for high level synthesis, with low-power, high-level design; Shows spec...

Fungal Tests

Science.gov (United States)

... Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 1569, 1570, 1532, 1616. Forbes, B. et. al. (© 2007). Bailey & Scott's Diagnostic Microbiology, Twelfth Edition: Mosby Elsevier Press, St. Louis, Missouri. ...

California's K-12 Public Schools. How Are They Doing?

National Research Council Canada - National Science Library

Carroll, Stephen J; Krop, Cathy; Arkes, Jeremy; Morrison, Peter A; Flanagan, Ann

2005-01-01

... are no longer performing as well as they did previously or as well as schools in other states. The primary objective of our study was to look closely at California's public system of kindergarten through twelfth grade (K-12...

A Review of Power Electronics for Wind Power

DEFF Research Database (Denmark)

Chen, Zhe

2011-01-01

The paper reviews the power electronic applications for wind energy systems. Main wind turbine systems with different generators and power electronic converters are described. The electrical topologies of wind farms with power electronic conversion are discussed. Power electronic applications...

Power generation costs. Coal - nuclear power

International Nuclear Information System (INIS)

1979-01-01

This supplement volume contains 17 separate chapters investigating the parameters which determine power generation costs on the basis of coal and nuclear power and a comparison of these. A detailed calculation model is given. The complex nature of this type of cost comparison is shown by a review of selected parameter constellation for coal-fired and nuclear power plants. The most favourable method of power generation can only be determined if all parameters are viewed together. One quite important parameter is the load factor, or rather the hours of operation. (UA) 891 UA/UA 892 AMO [de

Power Electronics

DEFF Research Database (Denmark)

Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

2008-01-01

is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

Nuclear and thermal power plant power ramping capability

International Nuclear Information System (INIS)

Golovach, E.A.

1983-01-01

The possibilities of step power increase by NPP and TPP units under emergency conditions of power grids operation are considered. The data analysis has shown that power units ramping capability with WWER-440, WWER-1000 and RBMK-1000 reactors is higher than that of 300 MW power units on fossil fuel, at the initial time interval (0-30 s). These NPP power units satisfy as to ramping capability the energy system requirements. Higher NPP power units ramping capability is explained by the fact that relative pressure before turbine valves is decreased less than in straight-through boilers while the steam volumes time constant of steam separator-superheaters is less than that of intermediate superheatings. Higher power unit ramping capability with WWER-440 and RBMK-1000 reactors as compared with the WWER-1000 reactor is pointed out as well as the increase of WWER-1000 power unit capability using high-speed turbines

Some power uprate issues in nuclear power plants

International Nuclear Information System (INIS)

Tipping, Philip

2008-01-01

Issues and themes concerned with nuclear power plant uprating are examined. Attention is brought to the fact that many candidate nuclear power plants for uprating have anyway been operated below their rated power for a significant part of their operating life. The key issues remain safety and reliability in operation at all times, irrespective of the nuclear power plant's chronological or design age or power rating. The effects of power uprates are discussed in terms of material aspects and expected demands on the systems, structures and components. The impact on operation and maintenance methods is indicated in terms of changes to the ageing surveillance programmes. Attention is brought to the necessity checking or revising operator actions after power up-rating has been implemented

Power market model with energy- and power dimension

International Nuclear Information System (INIS)

Johnsen, T.A.; Larsen, B.M.

1995-01-01

This report discusses a mathematical model of the Norwegian power market. The year is divided into three seasons. Each season is subdivided into a high-load period and a low-load period according to the demand. High-load occurs in daytime on workdays while low-load occurs at night and on holidays. The model is intended to be a tool for studying variations in prices, production, demand and trade throughout the year in a market of free competition. The model establishes equilibrium prices of electricity in Norway in high-load and low-load periods. Equilibrium prices with added transport tariffs and charges give customer an indication of the cost of using electricity. And the equilibrium prices indicate to the power producers the value of further energy or power capacity. Examples of calculations using the model show that extended export and import between Norway and other countries affect power prices and production in Norway. In the examples, power intensive industry and wood processing are subjected to market prices on energy. World market prices which give unilateral power export in the high-load periods cause the Norwegian power prices to rise strongly. If to the export from Norway in periods of high-load there corresponds import in periods of low-load, then the pressure on the prices in the power market is significantly reduced. A more extensive power exchange implies that foreign power producers may use the Norwegian power system to avoid large variations in their thermal power production. 23 refs., 21 figs., 1 tab

Fuel-cell based power generating system having power conditioning apparatus

Science.gov (United States)

Mazumder, Sudip K.; Pradhan, Sanjaya K.

2010-10-05

A power conditioner includes power converters for supplying power to a load, a set of selection switches corresponding to the power converters for selectively connecting the fuel-cell stack to the power converters, and another set of selection switches corresponding to the power converters for selectively connecting the battery to the power converters. The power conveners output combined power that substantially optimally meets a present demand of the load.

High impact data visualization with Power View, Power Map, and Power BI

CERN Document Server

Aspin, Adam

2014-01-01

High Impact Data Visualization with Power View, Power Map, and Power BI helps you take business intelligence delivery to a new level that is interactive, engaging, even fun, all while driving commercial success through sound decision-making. Learn to harness the power of Microsoft's flagship, self-service business intelligence suite to deliver compelling and interactive insight with remarkable ease. Learn the essential techniques needed to enhance the look and feel of reports and dashboards so that you can seize your audience's attention and provide them with clear and accurate information. Al

77 FR 3454 - Notice of Submission for OMB Review

Science.gov (United States)

2012-01-24

... twelfth grade public and private school teachers, principals, schools, library media centers, and school... public school districts, principals, schools, teachers and school libraries, the survey estimates are state-representative. For public charter schools, principals, teachers, and school libraries, the survey...

Nuclear power and other thermal power

International Nuclear Information System (INIS)

Bakke, J.

1978-01-01

Some philosophical aspects of mortality statistics are first briefly mentioued, then the environmental problems of, first, nuclear power plants, then fossil fuelled power plants are summarised. The effects of releases of carbon dioxide, sulphur dioxide and nitrogen oxides are briefly discussed. The possible health effects of radiation from nuclear power plants and those of gaseous and particulate effluents from fossil fuel plants are also discussed. It is pointed out that in choosing between alternative evils the worst course is to make no choice at all, that is, failure to install thermal power plants will lead to isolated domestic burning of fossil fuels which is clearly the worst situation regarding pollution. (JIW)

Bidding Strategy of Virtual Power Plant with Energy Storage Power Station and Photovoltaic and Wind Power

Directory of Open Access Journals (Sweden)

Zhongfu Tan

2018-01-01

Full Text Available For the virtual power plants containing energy storage power stations and photovoltaic and wind power, the output of PV and wind power is uncertain and virtual power plants must consider this uncertainty when they participate in the auction in the electricity market. In this context, this paper studies the bidding strategy of the virtual power plant with photovoltaic and wind power. Assuming that the upper and lower limits of the combined output of photovoltaic and wind power are stochastically variable, the fluctuation range of the day-ahead energy market and capacity price is stochastically variable. If the capacity of the storage station is large enough to stabilize the fluctuation of the output of the wind and photovoltaic power, virtual power plants can participate in the electricity market bidding. This paper constructs a robust optimization model of virtual power plant bidding strategy in the electricity market, which considers the cost of charge and discharge of energy storage power station and transmission congestion. The model proposed in this paper is solved by CPLEX; the example results show that the model is reasonable and the method is valid.

Recent development of levitation melting equipment; Fuyo yokai sochi (CCLM) no shinten

Energy Technology Data Exchange (ETDEWEB)

Tadano, H.; Kainuma, K. [Fuji Electric Furnace Co. Ltd., Mie (Japan)

1998-05-10

Fuji Electric Co., Ltd., is advancing its research and development efforts for cold crucible levitation melting (CCLM) equipment in which metal is caused to be levitated in the air and is melted. Such a unit consists of a water-cooled copper crucible, a water-cooled coil installed to surround the crucible, and a high-frequency power source. Eddy currents are induced in the crucible and metal upon application of a high-frequency current to the coil, and electromagnetic repulsion is generated between the eddy currents. When the force of repulsion is greater than the force of gravity acting on the metal, the metal leaves the crucible to be levitated in the air. At the same time, the metal is heated by the Joule heat produced by the eddy currents, and is melted. So far, for the stabilized levitation melting of a kilogram-level amount of metal, a double power source excitation system has been adopted and the crucible bottom configuration has been optimized. Also, non-contact tapping of molten metal from the bottom and increase of the molten metal amount to the 50 kilogram level have been achieved, these for the industrialization of the technology. Already available on the market are equipment for large-capacity CCLM, continuous casting CCLM, and the high-vacuum CCLM. 5 refs., 13 figs., 3 tabs.

Power Quality in DC Power Distribution Systems and Microgrids

Directory of Open Access Journals (Sweden)

Stephen Whaite

2015-05-01

Full Text Available This review paper discusses power quality considerations for direct current (DC electric power distribution systems, particularly DC microgrids. First, four selected sample DC architectures are discussed to provide motivation for the consideration of power quality in DC systems. Second, a brief overview of power quality challenges in conventional alternating current (AC distribution systems is given to establish the field of power quality. Finally, a survey of literature addressing power quality issues in DC systems is presented, and necessary power quality considerations in DC distribution system design and operation are discussed.

Economic Operation of Power Systems with Significant Wind Power Penetration

DEFF Research Database (Denmark)

Farashbashi-Astaneh, Seyed-Mostafa

This dissertation addresses economic operation of power systems with high penetration of wind power. Several studies are presented to address the economic operation of power systems with high penetration of variable wind power. The main concern in such power systems is high variability...... and unpredictability. Unlike conventional power plants, the output power of a wind farm is not controllable. This brings additional complexity to operation and planning of wind dominant power systems. The key solution in face of wind power uncertainty is to enhance power system flexibility. The enhanced flexibility......, cooperative wind-storage operation is studied. Lithium-Ion battery units are chosen as storage units. A novel formulation is proposed to investigate optimal operation of a storage unit considering power system balancing conditions and wind power imbalances. An optimization framework is presented to increase...

Liberation of electric power and nuclear power generation

International Nuclear Information System (INIS)

Yajima, Masayuki

2000-01-01

In Japan, as the Rule on Electric Business was revised after an interval of 35 years in 1995, and a competitive bid on new electric source was adopted after 1996 fiscal year, investigation on further competition introduction to electric power market was begun by establishment of the Basic Group of the Electric Business Council in 1997. By a report proposed on January, 1999 by the Group, the Rule was revised again on March, 1999 to start a partial liberation or retail of the electric power from March, 2000. From a viewpoint of energy security and for solution of global environmental problem in Japan it has been decided to positively promote nuclear power in future. Therefore, it is necessary to investigate how the competition introduction affects to development of nuclear power generation and what is a market liberation model capable of harmonizing with the development on liberation of electric power market. Here was elucidated on effect of the introduction on previous and future nuclear power generation, after introducing new aspects of nuclear power problems and investigating characteristic points and investment risks specific to the nuclear power generation. And, by investigating some possibilities to development of nuclear power generation under liberation models of each market, an implication was shown on how to be future liberation on electric power market in Japan. (G.K.)

Balancing computation and communication power in power constrained clusters

Science.gov (United States)

Piga, Leonardo; Paul, Indrani; Huang, Wei

2018-05-29

Systems, apparatuses, and methods for balancing computation and communication power in power constrained environments. A data processing cluster with a plurality of compute nodes may perform parallel processing of a workload in a power constrained environment. Nodes that finish tasks early may be power-gated based on one or more conditions. In some scenarios, a node may predict a wait duration and go into a reduced power consumption state if the wait duration is predicted to be greater than a threshold. The power saved by power-gating one or more nodes may be reassigned for use by other nodes. A cluster agent may be configured to reassign the unused power to the active nodes to expedite workload processing.

Critical success factors for BOT electric power projects in China: Thermal power versus wind power

Energy Technology Data Exchange (ETDEWEB)

Zhao, Zhen-Yu. [School of Business Administration, North China Electric Power University, Beijing 102206 (China); Zuo, Jian; Zillante, George [School of Natural and Built Environments, University of South Australia, Adelaide 5001 (Australia); Wang, Xin-Wei [Shandong Nuclear Power Equipment Manufacturing Co. Ltd, Haiyang, Shandong 265118 (China)

2010-06-15

Chinese electric power industry has adopted Build-Operate-Transfer (BOT) approach in a number of projects to alleviate the pressure of sole state-owned investment. The Chinese government has taken enormous efforts to create an environment to facilitate the application of BOT approach in electric power projects. Moreover, the growing attention on the sustainability issues puts the traditional major source of electricity - thermal power project under more strict scrutiny. As a result, various renewable energy projects, particularly the wind power projects have involved private sector funds. Both thermal power and wind power projects via BOT approach have met with a varying degree of success. Therefore, it is imperative to understand the factors contributing towards the success of both types of BOT power projects. Using an extensive literature survey, this paper identifies 31 success factors under 5 categories for Chinese BOT electric power projects. This is followed by a questionnaire survey to exam relative significance of these factors. The results reveal the different levels of significance of success factors for BOT thermal power projects versus wind power projects. Finally, survey results were analyzed to explore the underlying construction and distributions among the identified success factors. This study provides a valuable reference for all involved parties that are interested in developing BOT electric power projects in China. (author)

An ecological solution in power development strategy: hydroelectric Power

International Nuclear Information System (INIS)

Ionescu, S.; Teodorescu, D.

1994-01-01

One of the fundamental criteria in establishing the power development strategy is represented by the environmental protection. Besides increasing the power efficiency for users, the hydro power stands for a handy alternative to generate thermal power. Comparatively, if hydro power is properly planed and developed, it could allow conservation of fossil fuel resources (as it makes use of a renewable resources) and avoids air and water pollution and in addition would lead to certain positive effects upon the natural and anthropic environment (flood routing, optimizes the power supply-demand relationship, and so on). By making use of the data available in the international specific literature and the information on the power development strategy in Romania the effects incurred by hydro power are both qualitatively and quantitatively emphasized as compared to alternative power generation by fossil fuel combustion. The proposal is made to adopt certain law regulations as well as a methodology to evaluate the general efficiency of various types of power generating devices suiting the particular conditions of Romania and taking into account the social cost as well as environmental effects. Hence a power development strategy could be undertaking at the national level provided it meets the requirements of both power system and environment protection. (Author)

Alternative off-site power supply improves nuclear power plant safety

International Nuclear Information System (INIS)

Gjorgiev, Blaže; Volkanovski, Andrija; Kančev, Duško; Čepin, Marko

2014-01-01

Highlights: • Additional power supply for mitigation of the station blackout event in NPP is used. • A hydro power plant is considered as an off-site alternative power supply. • An upgrade of the probabilistic safety assessment from its traditional use is made. • The obtained results show improvement of nuclear power plant safety. - Abstract: A reliable power system is important for safe operation of the nuclear power plants. The station blackout event is of great importance for nuclear power plant safety. This event is caused by the loss of all alternating current power supply to the safety and non-safety buses of the nuclear power plant. In this study an independent electrical connection between a pumped-storage hydro power plant and a nuclear power plant is assumed as a standpoint for safety and reliability analysis. The pumped-storage hydro power plant is considered as an alternative power supply. The connection with conventional accumulation type of hydro power plant is analysed in addition. The objective of this paper is to investigate the improvement of nuclear power plant safety resulting from the consideration of the alternative power supplies. The safety of the nuclear power plant is analysed through the core damage frequency, a risk measure assess by the probabilistic safety assessment. The presented method upgrades the probabilistic safety assessment from its common traditional use in sense that it considers non-plant sited systems. The obtained results show significant decrease of the core damage frequency, indicating improvement of nuclear safety if hydro power plant is introduced as an alternative off-site power source

Power Talk

DEFF Research Database (Denmark)

Angjelichinoski, Marko; Stefanovic, Cedomir; Popovski, Petar

2016-01-01

A standard way to realize communication in microgrid control is to use an external communication network, such as modems for wireless or power-line communication, whose implementation may be inefficient in terms of deployment cost, complexity, and system stability. In this chapter we present......, while its reliability and availability draw on the reliability and availability of the microgrid power transmission system....... a communication solution, denoted as power talk, which is solely based on the use of the existing microgrid power equipment (i.e., power electronics and buses). The pivotal idea is to modulate information in the power-related parameters of the microgrid buses by use of the flexibility of power electronic...

Switching power converters medium and high power

CERN Document Server

Neacsu, Dorin O

2013-01-01

An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

Power in Households: Disentangling Bargaining Power

OpenAIRE

Mabsout, Ramzi; Staveren, Irene

2009-01-01

textabstractIntroduction Within the household bargaining literature, bargaining power is generally understood in terms of economic resources, such as income or assets. Empirical analyses of women’s bargaining power in households in developed and developing countries find that, in general, higher female incomes lead to higher bargaining power, which in turn tends to increase women’s relative wellbeing (Quisumbing, 2003). For assets, the empirical literature comes up with similar results, indic...

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-26

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-01

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

Power conditioning unit for photovoltaic power systems

Science.gov (United States)

Beghin, G.; Nguyen Phuoc, V. T.

Operational features and components of a power conditioning unit for interconnecting solar cell module powers with a utility grid are outlined. The two-stage unit first modifies the voltage to desired levels on an internal dc link, then inverts the current in 2 power transformers connected to a vector summation control to neutralize harmonic distortion up to the 11th harmonic. The system operates in parallel with the grid with extra inductors to absorb line-to-line voltage and phase differences, and permits peak power use from the PV array. Reactive power is gained internally, and a power system controller monitors voltages, frequencies, and currents. A booster preregulator adjusts the input voltage from the array to provide voltage regulation for the inverter, and can commutate 450 amps. A total harmonic distortion of less than 5 percent is claimed, with a rating of 5 kVA, 50/60 Hz, 3-phase, and 4-wire.

When Power Shapes Interpersonal Behavior: Low Relationship Power Predicts Men’s Aggressive Responses to Low Situational Power

Science.gov (United States)

Overall, Nickola C.; Hammond, Matthew D.; McNulty, James K.; Finkel, Eli J.

2016-01-01

When does power in intimate relationships shape important interpersonal behaviors, such as psychological aggression? Five studies tested whether possessing low relationship power was associated with aggressive responses, but (1) only within power-relevant relationship interactions when situational power was low, and (2) only by men because masculinity (but not femininity) involves the possession and demonstration of power. In Studies 1 and 2, men lower in relationship power exhibited greater aggressive communication during couples’ observed conflict discussions, but only when they experienced low situational power because they were unable to influence their partner. In Study 3, men lower in relationship power reported greater daily aggressive responses toward their partner, but only on days when they experienced low situational power because they were either (a) unable to influence their partner or (b) dependent on their partner for support. In Study 4, men who possessed lower relationship power exhibited greater aggressive responses during couples’ support-relevant discussions, but only when they had low situational power because they needed high levels of support. Study 5 provided evidence for the theoretical mechanism underlying men’s aggressive responses to low relationship power. Men who possessed lower relationship power felt less manly on days they faced low situational power because their partner was unwilling to change to resolve relationship problems, which in turn predicted greater aggressive responses to their partner. These results demonstrate that fully understanding when and why power is associated with interpersonal behavior requires differentiating between relationship and situational power. PMID:27442766

Power oscillation suppression by robust SMES in power system with large wind power penetration

International Nuclear Information System (INIS)

Ngamroo, Issarachai; Cuk Supriyadi, A.N.; Dechanupaprittha, Sanchai; Mitani, Yasunori

2009-01-01

The large penetration of wind farm into interconnected power systems may cause the severe problem of tie-line power oscillations. To suppress power oscillations, the superconducting magnetic energy storage (SMES) which is able to control active and reactive powers simultaneously, can be applied. On the other hand, several generating and loading conditions, variation of system parameters, etc., cause uncertainties in the system. The SMES controller designed without considering system uncertainties may fail to suppress power oscillations. To enhance the robustness of SMES controller against system uncertainties, this paper proposes a robust control design of SMES by taking system uncertainties into account. The inverse additive perturbation is applied to represent the unstructured system uncertainties and included in power system modeling. The configuration of active and reactive power controllers is the first-order lead-lag compensator with single input feedback. To tune the controller parameters, the optimization problem is formulated based on the enhancement of robust stability margin. The particle swarm optimization is used to solve the problem and achieve the controller parameters. Simulation studies in the six-area interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions

Power oscillation suppression by robust SMES in power system with large wind power penetration

Science.gov (United States)

Ngamroo, Issarachai; Cuk Supriyadi, A. N.; Dechanupaprittha, Sanchai; Mitani, Yasunori

2009-01-01

The large penetration of wind farm into interconnected power systems may cause the severe problem of tie-line power oscillations. To suppress power oscillations, the superconducting magnetic energy storage (SMES) which is able to control active and reactive powers simultaneously, can be applied. On the other hand, several generating and loading conditions, variation of system parameters, etc., cause uncertainties in the system. The SMES controller designed without considering system uncertainties may fail to suppress power oscillations. To enhance the robustness of SMES controller against system uncertainties, this paper proposes a robust control design of SMES by taking system uncertainties into account. The inverse additive perturbation is applied to represent the unstructured system uncertainties and included in power system modeling. The configuration of active and reactive power controllers is the first-order lead-lag compensator with single input feedback. To tune the controller parameters, the optimization problem is formulated based on the enhancement of robust stability margin. The particle swarm optimization is used to solve the problem and achieve the controller parameters. Simulation studies in the six-area interconnected power system with wind farms confirm the robustness of the proposed SMES under various operating conditions.

Is power-space a continuum? Distance effect during power judgments.

Science.gov (United States)

Jiang, Tianjiao; Zhu, Lei

2015-12-01

Despite the increasing evidence suggesting that power processing can activate vertical space schema, it still remains unclear whether this power-space is dichotomic or continuous. Here we tested the nature of the power-space by the distance effect, a continuous property of space cognition. In two experiments, participants were required to judge the power of one single word (Experiment 1) or compare the power of two words presented in pairs (Experiment 2). The power distance was indexed by the absolute difference of power ratings. Results demonstrated that reaction time decreased with the power distance, whereas accuracy increased with the power distance. The findings indicated that different levels of power were presented as different vertical heights, implying that there was a common mechanism underlying space and power cognition. Copyright © 2015 Elsevier Inc. All rights reserved.

Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i3.8046 Use of alternative media and different types of recipients in a laboratory culture of Ankistrodesmus gracilis (Reinsch Korshikov (Chlorophyceae - doi: 10.4025/actascibiolsci.v33i3.8046

Directory of Open Access Journals (Sweden)

Flávia de Almeida Berchielli

2011-07-01

Full Text Available A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12 and in two alternative culture media, NPK (20-5-20 and macrophyte (Eichhornia crassipes + NPK, in three different types of recipients (fiberglass, carboy and plastic bag. First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1 in a fiberglass recipient. However, highest density (p 12 (122.87 x 105 cells mL-1 in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05 in culture media in the three recipients. Protein and fiber were similar (p > 0.05 in the treatments, but lipids were higher (p -1 in NPK (p A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the laboratory.A laboratory culture of Ankistrodesmus gracilis algae was evaluated by studying the biology of the species and its chemical composition in a traditional medium (CHU12 and in two alternative culture media, NPK (20-5-20 and macrophyte (Eichhornia crassipes + NPK, in three different types of recipients (fiberglass, carboy and plastic bag. First peak in the growth curve of Ankistrodesmus gracilis occurred on the ninth day in macrophyte + NPK medium (74.16 x 105 cells mL-1 in a fiberglass recipient. However, highest density (p 12 (122.87 x 105 cells mL-1 in a plastic bag on the twelfth day. Cell density was over 70 x 105 cells mL-1 starting on the twelfth day. Growth rate of A. gracilis was similar (p > 0.05 in culture media in the three recipients. Protein and fiber were similar (p > 0.05 in the treatments, but lipids were higher (p -1 in NPK (p A. gracilis cultured in three types of recipients. Costs are low, occupying less space when cultured in plastic bags and in the

The electric power engineering handbook power systems

CERN Document Server

2012-01-01

Power Systems, Third Edition (part of the five-volume set, The Electric Power Engineering Handbook) covers all aspects of power system protection, dynamics, stability, operation, and control. Under the editorial guidance of L.L. Grigsby, a respected and accomplished authority in power engineering, and section editors Andrew Hanson, Pritindra Chowdhuri, Gerry Sheble, and Mark Nelms, this carefully crafted reference includes substantial new and revised contributions from worldwide leaders in the field. This content provides convenient access to overviews and detailed information on a diverse arr

Power electronics and control for wind power systems

DEFF Research Database (Denmark)

Iov, Florin; Blaabjerg, Frede

2009-01-01

energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...

Normative Power

DEFF Research Database (Denmark)

's normative power than any other academic journal, including a special issue on "What Kind of Power?" in 2006. As the leading journal in the debate, this special issue brings together seven normative power articles published in JEPP since the 2006 special issue, together with Ian Manners' ‘Normative power......The social sciences have many different understandings of ‘normative power', but in European Union (EU) studies normative power has three particular meanings. The first meaning of normative power is its emphasis on normative theory, that is, how we judge and justify truth claims in social science...... effects of EU relations with the world in areas ranging from inter-regional relations, through traditional diplomacy, to environmental politics. Research areas of particular interest include the study of the interplay between physical, material and normative forms of power, as well as the constitutive...

Agent-based power sharing scheme for active hybrid power sources

Science.gov (United States)

Jiang, Zhenhua

The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

Power in Bourdieu and Foucault: considerations about symbolic power and disciplinary power

Directory of Open Access Journals (Sweden)

Tiago Barros Rosa

2017-06-01

Full Text Available This article aims to present some of conceptions about power, which are present in the thoughts of two contemporary classics from Social Science: Pierre Bourdieu and Michel Foucault. Most specifically, we will analyze the foundations of the notions of symbolic power and disciplinary power, developed, respectively, on their work. Despite the theoretical and methodological differences in both authors, we attend to approach the distinct notions of power in their scientific projects and to confront them to the currently dominant tendency, whose fundamental assumption are supported by the Weberian theory. The idea of imposition of will, as discussed in Weber’s classic formulation of power, brings in itself, indelibly, the awareness, calculation and intentionality by the social actors. Both Foucault and Bordieu, the individuals - subjects and social agents – are conditioned and constrained by external relation and forces, which are often not consciously perceived.

Characteristics of The Magnet Wheel As A Magnetic Levitation Device of Induction Type

OpenAIRE

藤井, 信男; 小川, 幸吉; 松本, 敏雄; Nobuo, FUJII; Kokichi, OGAWA; Toshio, MATSUMOTO; 九州大学; 大分大学; 安川電機; Kyushu University; Oita University; Yaskawa Electric Co., Ltd.

1996-01-01

A new type of magnetic wheel called the "magnet wheel" has been proposed. The magnet wheel has both magnetic levitation and linear drive functions combined into one. In the magnet wheel, the permanent magnets are rotated over the conducting plate so that an induction type of repulsive lift force is obtained. To produce thrust from the drag torque which is simultaneously induced with the lift force, the "tilt type" and "partial overlap type" magnet wheels have been proposed. Poor power factor ...

Integrating wind power in the (French) power system

International Nuclear Information System (INIS)

Pellen, A.

2007-03-01

RTE and EDF have no other technological option than to restrain the contribution of the French wind power fleet to base-load generation where it comes in direct competition with the nuclear power plants. The author aims to explain this situation and answer the following questions. Why the fossil fueled reactor fleet in France will not be affected by an evolution of the wind power capacity? Why, in France electric power generation-demand SYSTEM wind power cannot be a substitute for fossil fueled thermal units? (A.L.B.)

Power quality in power systems and electrical machines

CERN Document Server

Fuchs, Ewald

2015-01-01

The second edition of this must-have reference covers power quality issues in four parts, including new discussions related to renewable energy systems. The first part of the book provides background on causes, effects, standards, and measurements of power quality and harmonics. Once the basics are established the authors move on to harmonic modeling of power systems, including components and apparatus (electric machines). The final part of the book is devoted to power quality mitigation approaches and devices, and the fourth part extends the analysis to power quality solutions for renewable

Influence of Family Processes, Motivation, and Beliefs about Intelligence on Creative Problem Solving of Scientifically Talented Individuals

Science.gov (United States)

Cho, Seokhee; Lin, Chia-Yi

2011-01-01

Predictive relationships among perceived family processes, intrinsic and extrinsic motivation, incremental beliefs about intelligence, confidence in intelligence, and creative problem-solving practices in mathematics and science were examined. Participants were 733 scientifically talented Korean students in fourth through twelfth grades as well as…

Digital assessment-driven examples-based mathematics for computer science students

NARCIS (Netherlands)

Heck, A.; Brouwer, N.; Amado, N.; Carreira, S.

2015-01-01

nnovation, inclusion, sharing and diversity are some of the words that briefly and suitably characterize the ICTMT series of biennial international conferences - the International Conference on Technology in Mathematics Teaching. Being the twelfth of a series which began in Birmingham, UK, in 1993,

Physical Attractiveness, Attitude Similarity, and Length of Acquaintance as Contributors to Interpersonal Attraction Among Adolescents

Science.gov (United States)

Cavior, Norman; And Others

1975-01-01

Tenth and twelfth grade males and females who knew each other judged, within grade levels, their classmates on physical attractiveness (PA), perceived attitude similarity (PAS), and interpersonal attraction (IA). Regression analyses supported the hypotheses that PA and PAS are positively correlated. (Author)

Advances in geophysical technologies for the exploration and safe mining of deep gold ore bodies in the Witwatersrand basin, South Africa

CSIR Research Space (South Africa)

Durrheim, RJ

2013-08-01

Full Text Available -1 Proceedings of the Twelfth Biennial Meeting of the Society for Geology Applied to Mineral Deposits, Uppsala, Sweden, 12-15 August 2013 Advances in geophysical technologies for the exploration and safe mining of deep gold ore bodies in the Witwatersrand...

Environmental Education and K-12 Student Outcomes: A Review and Analysis of Research

Science.gov (United States)

Ardoin, Nicole M.; Bowers, Alison W.; Roth, Noelle Wyman; Holthuis, Nicole

2018-01-01

Many practitioners and researchers describe academic and environmental benefits of environmental education for kindergarten through twelfth grade (K-12) students. To consider the empirical underpinnings of those program descriptions, we systematically analyzed the peer-reviewed literature (1994-2013), focusing on outcomes of environmental…

Experimental Analysis of a Coupled Energy Harvesting System with Monostable and Bistable Configuration

International Nuclear Information System (INIS)

Hoffmann, D; Folkmer, B; Manoli, Y

2014-01-01

In this paper we present experimental results from an energy harvesting system with two coupled energy harvesters. The energy conversion mechanism of the two coupled energy harvesters is based on the electromagnetic principle. The coupling is generated by two magnets in a repulsive arrangement. In this manner a bistable configuration can be obtained if the gap between the magnets is sufficiently small. We demonstrate that the total power output can be increased in comparison to a linear reference system, if specific conditions are fulfilled. In this respect, the highest power output occurs in the nonlinear region of a monostable system configuration, mostly near the transition to a bistable configuration. On the other hand, the results also indicate, that a bistable operating mode does not necessarily enhance the power output of the coupled system

Adaptive Reactive Power Control of PV Power Plants for Improved Power Transfer Capability under Ultra-Weak Grid Conditions

DEFF Research Database (Denmark)

Yang, Dongsheng; Wang, Xiongfei; Liu, Fangcheng

2018-01-01

with the unity power factor. Then, considering the reactive power compensation from PV inverters, the minimum SCR in respect to Power Factor (PF) is derived, and the optimized coordination of the active and reactive power is exploited. It is revealed that the power transfer capability of PV power plant under...... of a 200 MW PV power plant demonstrate that the proposed method can ensure the rated power transfer of PV power plant with the SCR of 1.25, provided that the PV inverters are operated with the minimal PF=0.9.......This paper analyzes the power transfer limitation of the PV power plant under the ultra-weak grid condition, i.e., when the Short-Circuit Ratio (SCR) is close to 1. It explicitly identifies that a minimum SCR of 2 is required for the PV power plant to deliver the rated active power when operating...