WorldWideScience

Sample records for twelfth power repulsion

  1. Playing the role: Power of love and love of power in Shakespeare's Twelfth Night

    Directory of Open Access Journals (Sweden)

    Ljubica Matek

    2014-12-01

    Full Text Available The author uses a methodological approach similar to one of New Historicism to give a new reading of Shakespeare’s comedy Twelfth Night, or What You Will. The play represents both a literary and a historical document which repeats the pattern of appropriating and exercising power used by Queen Elizabeth I. This reading reveals a new interpretative layer of Shakespeare’s seemingly apolitical comedy about mistaken identity and unrequited love which is resolved in a likewise seemingly typical happy ending that includes three marriages. A parallel analysis of text and context will show that Twelfth Night is a socially subversive text which points to the conclusion that masking seems to be a necessary prerequisite for achieving personal and political goals, both in the fictional context of the play and in the historical context of Elizabethan England.

  2. Attractive and Repulsive Particle Swarm Optimization and Random Virus Algorithm for Solving Reactive Power Optimization Problem

    Directory of Open Access Journals (Sweden)

    K. Lenin

    2013-03-01

    Full Text Available Reactive Power Optimization is a complex combinatorial optimization problem involving non-linear function having multiple local minima, non-linear and discontinuous constrains. This paper presents Attractive and repulsive Particle Swarm Optimization (ARPSO and Random Virus Algorithm (RVA in trying to overcome the Problem of premature convergence. RVA and ARPSO is applied to Reactive Power Optimization problem and is evaluated on standard IEEE 30Bus System. The results show that RVA prevents premature convergence to high degree but still keeps a rapid convergence. It gives best solution when compared to Attractive and repulsive Particle Swarm Optimization (ARPSO and Particle Swarm Optimization (PSO.

  3. Neutron Repulsion

    CERN Document Server

    Manuel, Oliver K

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch that locked together these puzzling space-age observations: 1.) Excess 136Xe accompanied primordial helium in the stellar debris that formed the solar system (Fig. 1); 2.) The Sun formed on the supernova core (Fig. 2); 3.) Waste products from the core pass through an iron-rich mantle, selectively carrying lighter elements and lighter isotopes of each element into the photosphere (Figs. 3-4); and 4.) Neutron repulsion powers the Sun and sustains life (Figs. 5-7). Together these findings offer a framework for understanding...

  4. 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 γr-α . Such systems are useful in modeling melting transitions. The limit α→∞ corresponds to the hard sphere gas. A thermodynamic limit exists only for short-range (α>3) and repulsive (γ>0) interactions. The geometric theory solutions for given α>3 , γ>0 , and any constant temperature T have the following properties: (1) the thermodynamics follows from a single function b(ρT-3/α) , where ρ is the density; (2) all solutions are equivalent up to a single scaling constant for ρT-3/α , related to γ 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 α>3 we may include a first-order phase transition, which is expected from computer simulations; and (8) if α→∞ , the density approaches a finite value as the pressure increases to infinity, with the pressure diverging logarithmically in the density difference.

  5. 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.

  6. Neutron Repulsion

    OpenAIRE

    Manuel, Oliver K.

    2011-01-01

    Earth is connected gravitationally, magnetically and electrically to its heat source - a neutron star that is obscured from view by waste products in the photosphere. Neutron repulsion is like the hot filament in an incandescent light bulb. Excited neutrons are emitted from the solar core and decay into hydrogen that glows in the photosphere like a frosted light bulb. Neutron repulsion was recognized in nuclear rest mass data in 2000 as the overlooked source of energy, the keystone of an arch...

  7. 内蒙古自治区“十二五”期间煤电发展空间测算%Calculation of coal power development during the “Twelfth Five Planning” in Inner Mongolia

    Institute of Scientific and Technical Information of China (English)

    卢艳丽; 宋志博

    2015-01-01

    根据内蒙古自治区2010年的 SO2和 NOx 排放现状,结合现行减排政策和排放标准要求,分析“十二五”期间内蒙古现役源的 SO2和 NOx 减排潜力。根据“十二五”SO2和 NOx 总量控制目标,分析新源可用的排放指标空间。测算“十二五”期间非电力行业的污染物排放增量,在此基础上分析电力行业排放指标空间可供发展的新建燃煤机组规模。%According to the SO2 and NOx emission status of the Inner Mongolia in 2010,according to the current emission reduction policies and emission standards, SO2 and NOx emission reduction potential of Inner Mongolia active source analysis of the " Twelfth Five Planning " period. According to the SO2 and NOx total control objectives of the "Twelfth Five Planning ", analysis of space available source emission index. Calculation of the " Twelfth Five Planning " period in nonpower industry increment of pollutant emissions, the scale of the new coal-fired units on the basis of analysis of emission index of electric power industry for the development of space.

  8. Electromagnetic-Repulsion Systems For Deicing Aircraft

    Science.gov (United States)

    Smith, Samuel O.; Zieve, Peter

    1994-01-01

    Improved eddy-current electromagnetic-repulsion deicing systems developed for use on variety of exterior aircraft surfaces like leading edges of wings, engine inlets, propellers, and helicopter rotors. Fit to exterior surfaces, as retrofits or original equipment. Systems light in weight, consume little average power, and capable of protecting against severe icing conditions.

  9. Twelfth degree spline with application to quadrature.

    Science.gov (United States)

    Mohammed, P O; Hamasalh, F K

    2016-01-01

    In this paper existence and uniqueness of twelfth degree spline is proved with application to quadrature. This formula is in the class of splines of degree 12 and continuity order [Formula: see text] that matches the derivatives up to order 6 at the knots of a uniform partition. Some mistakes in the literature are pointed out and corrected. Numerical examples are given to illustrate the applicability and efficiency of the new method.

  10. Magnetic Repulsion: An Introductory Experiment

    Science.gov (United States)

    Romer, Alfred

    1973-01-01

    Discusses the use of a balance assembled from standard laboratory components to conduct an experiment on the repulsion between two bar magnets. Includes an analysis of data on the two-pole and four-pole models. (CC)

  11. Omani Twelfth Grade Students' Most Common Misconceptions in Chemistry

    Science.gov (United States)

    Al-Balushi, Sulaiman M.; Ambusaidi, Abdullah K.; Al-Shuaili, Ali H.; Taylor, Neil

    2012-01-01

    The current study, undertaken in the Sultanate of Oman, explored twelfth grade students' common misconceptions in seven chemistry conceptual areas. The sample included 786 twelfth grade students in Oman while the instrument was a two-tier test called Chemistry Misconceptions Diagnostic Test (CMDT), consisting of 25 items with 12 items…

  12. 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

  13. 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....

  14. Twelfth Thermal and Fluids Analysis Workshop

    Science.gov (United States)

    Majumdar, Alok (Compiler)

    2002-01-01

    The Twelfth Thermal and Fluids Analysis Workshop (TFAWS 01) was held at the Bevill Center, The University of Alabama in Huntsville, Huntsville, Alabama, September 10-14, 2001. The theme for the hands-on training workshop and conference was "Engineering Excellence and Advances in the New Millenium." Forty-five technical papers were presented in four sessions: (1) Thermal Spacecraft/Payloads, (2) Thermal Propulsion/Vehicles, (3) Interdisciplinary Papers, and (4) Fluids Papers. Thirty-nine papers were published in these proceedings. The remaining six papers were not available in electronic format at the time of publication. In addition to the technical papers, there were (a) nine hands-on classes on thermal and flow analyses software, (b) thirteen short courses and product overview lectures, (c) five keynote lectures and, (d) panel discussions consisting of eight presentations. The workshop resulted in participation of 195 persons representing NASA Centers, Government agencies, aerospace industries, academia, software providers, and private corporations.

  15. “Textile Industry Twelfth Five Year Development Plan” issued

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Recently, the "Textile Industry Twelfth Five Year Development Plan" (hereinafter "Plan") has been issued by the Ministry of Industry and Information Technology, has been published to the public. The Plan highlights the restructuring, innovation, brand building

  16. 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.

  17. Characterizing repulsive gravity with curvature eigenvalues

    Science.gov (United States)

    Luongo, Orlando; Quevedo, Hernando

    2014-10-01

    Repulsive gravity has been investigated in several scenarios near compact objects by using different intuitive approaches. Here, we propose an invariant method to characterize regions of repulsive gravity, associated to black holes and naked singularities. Our method is based upon the behavior of the curvature tensor eigenvalues, and leads to an invariant definition of a repulsion radius. The repulsion radius determines a physical region, which can be interpreted as a repulsion sphere, where the effects due to repulsive gravity naturally arise. Further, we show that the use of effective masses to characterize repulsion regions can lead to coordinate-dependent results whereas, in our approach, repulsion emerges as a consequence of the spacetime geometry in a completely invariant way. Our definition is tested in the spacetime of an electrically charged Kerr naked singularity and in all its limiting cases. We show that a positive mass can generate repulsive gravity if it is equipped with an electric charge or an angular momentum. We obtain reasonable results for the spacetime regions contained inside the repulsion sphere whose size and shape depend on the value of the mass, charge and angular momentum. Consequently, we define repulsive gravity as a classical relativistic effect by using the geometry of spacetime only.

  18. Repulsive Casimir Force using metamaterials

    Science.gov (United States)

    Pappakrishnan, Venkatesh K.; Mundru, Pattabhiraju C.; Genov, Dentcho A.

    We investigate conditions for Casimir Force (CF) reversal between two parallel half-space metamaterial plates separated by air or vacuum at ambient temperatures. Practically, the Casimir effect can lead to stiction in nanoscale devices, degradation and decreased performance. While material realizations of repulsive CF has been proposed for high dielectric host materials, so far the CF reversal with air/vacuum as intermediate medium remain challenging. Here, we propose a two plate design based on artificial electromagnetic materials known as metamaterials. This configuration allows a simple analytical treatment that accurately describes the large and short distance asymptotics of CF and allows extraction of important parameters such as lower and upper cutoff gap distances that define the repulsive force window. A parametric study has been performed in terms of the plate's dielectric and magnetic plasma frequencies, plate separation distance and temperature. The parametric domain for achieving CF reversal is identified. If successfully implemented the proposed design could potentially result in frictionless bio-fluid transport devices, quantum levitation and coating for ultra-clean room environment.

  19. Gravitational Repulsion and Dirac Antimatter

    Science.gov (United States)

    Kowitt, Mark E.

    1996-03-01

    Based on an analogy with electron and hole dynamics in semiconductors, Dirac's relativistic electron equation is generalized to include a gravitational interaction using an electromagnetic-type approximation of the gravitational potential. With gravitational and inertial masses decoupled, the equation serves to extend Dirac's deduction of antimatter parameters to include the possibility of gravitational repulsion between matter and antimatter. Consequences for general relativity and related “antigravity” issues are considered, including the nature and gravitational behavior of virtual photons, virtual pairs, and negative-energy particles. Basic cosmological implications of antigravity are explored—in particular, potential contributions to inflation, expansion, and the general absence of detectable antimatter. Experimental and observational tests are noted, and new ones suggested.

  20. Repulsive Casimir Force in Chiral Metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, R.; Zhou, J.; Koschny, Th.; Economou, E.N.; Soukoulis, C.M.

    2009-09-04

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy possibly exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  1. Repulsive Casimir Force in Chiral Metamaterials

    OpenAIRE

    Zhao, R.; J. Zhou; Koschny, Th.; Economou, E. N.; C M Soukoulis

    2009-01-01

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  2. Repulsive Casimir Force in Chiral Metamaterials

    Science.gov (United States)

    Zhao, R.; Zhou, J.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2009-09-01

    We demonstrate theoretically that one can obtain repulsive Casimir forces and stable nanolevitations by using chiral metamaterials. By extending the Lifshitz theory to treat chiral metamaterials, we find that a repulsive force and a minimum of the interaction energy possibly exist for strong chirality, under realistic frequency dependencies and correct limiting values (for zero and infinite frequencies) of the permittivity, permeability, and chiral coefficients.

  3. Modeling Repulsive Gravity with Creation

    Indian Academy of Sciences (India)

    R. G. Vishwakarma; J. V. Narlikar

    2007-03-01

    There is a growing interest among cosmologists for theories with negative energy scalar fields and creation, in order to model a repulsive gravity. The classical steady state cosmology proposed by Bondi, Gold & Hoyle in 1948, was the first such theory which used a negative kinetic energy creation field to invoke creation of matter. We emphasize that creation plays a very crucial role in cosmology and provides a natural explanation to the various explosive phenomena occurring in local ( < 0.1) and extra galactic universe.We exemplify this point of view by considering the resurrected version of this theory – the quasi-steady state theory, which tries to relate creation events directly to the large scale dynamics of the universe and supplies more natural explanations of the observed phenomena. Although the theory predicts a decelerating universe at the present era, it explains successfully the recent SNe Ia observations (which require an accelerating universe in the standard cosmology), as we show in this paper by performing a Bayesian analysis of the data.

  4. Repulsive Casimir and Casimir-Polder Forces

    CERN Document Server

    Milton, Kimball A; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen A

    2012-01-01

    Casimir and Casimir-Polder repulsion have been known for more than 50 years. The general "Lifshitz" configuration of parallel semi-infinite dielectric slabs permits repulsion if they are separated by a dielectric fluid that has a value of permittivity that is intermediate between those of the dielectric slabs. This was indirectly confirmed in the 1970s, and more directly by Capasso's group recently. It has also been known for many years that electrically and magnetically polarizable bodies can experience a repulsive quantum vacuum force. More amenable to practical application are situations where repulsion could be achieved between ordinary conducting and dielectric bodies in vacuum. The status of the field of Casimir repulsion with emphasis on recent developments will be reviewed. Here, stress will be placed on analytic developments, especially of Casimir-Polder (CP) interactions between anisotropically polarizable atoms, and CP interactions between anisotropic atoms and bodies that also exhibit anisotropy, ...

  5. Repulsion between oppositely charged planar macroions.

    Directory of Open Access Journals (Sweden)

    YongSeok Jho

    Full Text Available The repulsive interaction between oppositely charged macroions is investigated using Grand Canonical Monte Carlo simulations of an unrestricted primitive model, including the effect of inhomogeneous surface charge and its density, the depth of surface charge, the cation size, and the dielectric permittivity of solvent and macroions, and their contrast. The origin of the repulsion is a combination of osmotic pressure and ionic screening resulting from excess salt between the macroions. The excess charge over-reduces the electrostatic attraction between macroions and raises the entropic repulsion. The magnitude of the repulsion increases when the dielectric constant of the solvent is lowered (below that of water and/or the surface charge density is increased, in good agreement with experiment. Smaller size of surface charge and the cation, their discreteness and mobility are other factors that enhance the repulsion and charge inversion phenomenons.

  6. Enhancing Casimir repulsion via topological insulator multilayers

    Science.gov (United States)

    Zeng, Ran; Chen, Liang; Nie, Wenjie; Bi, Meihua; Yang, Yaping; Zhu, Shiyao

    2016-08-01

    We propose to observe the enhanced Casimir repulsion between two parallel multilayer walls made of alternating layers of a topological insulator (TI) and a normal insulator. Based on the transfer matrix method, the Fresnel coefficients matrix is generalized to apply to the TI multilayer structure. The Casimir repulsion under the influence of the magnetization orientation in the magnetic coatings on TI layer surfaces, the layer thicknesses, and the topological magnetoelectric polarizability, is investigated. We show that, for the multilayer structures with parallel magnetization on the TI layer surfaces, it is possible to enhance the repulsion by increasing the TI layer number, which is due to the accumulation of the contribution to the repulsion from the polarization rotation effect occurring on each TI layer surface. Generally, in the distance region where there is Casimir attraction between semi-infinite TIs, the force may turn into repulsion in TI multilayer structure, and in the region of repulsion for semi-infinite TI, the repulsive force can be enhanced in magnitude, the enhancement tends to a maximum while the structure contains sufficiently many layers.

  7. Toward an invariant definition of repulsive gravity

    CERN Document Server

    Luongo, Orlando

    2010-01-01

    A remarkable property of naked singularities in general relativity is their repulsive nature. The effects generated by repulsive gravity are usually investigated by analyzing the trajectories of test particles which move in the effective potential of a naked singularity. This method is, however, coordinate and observer dependent. We propose to use the properties of the Riemann tensor in order to establish in an invariant manner the regions where repulsive gravity plays a dominant role. In particular, we show that in the case of the Kerr-Newman singularity and its special subcases the method delivers plausible results.

  8. Twelfth night of 1917 and the Moscow art theatre Twelfth night of 1917 and the Moscow art theatre

    Directory of Open Access Journals (Sweden)

    Arkady Ostrovsky

    2008-04-01

    Full Text Available On 15 September, 1917, in a letter to Nemirovich-Danchenko, Stanislavsky renounced the stage of the Moscow Art Theatre: I cannot think about any other roles, because I will never be able to do anything, at least in the Moscow Art Theatre. Maybe in some other area or some other place I will be able to rise. Of course I do not mean in other theatres, but in the studios. Othello — free!...1 After the tragedy Stanislavsky had endured with Selo Stepanchikovo, he threw himself into Studio work. He started rehearsing Twelfth Night, a play he had put on at the Society of Art and Literature in 1897. The Studio production of Twelfth Night was played on 25 December 1917, two months to the day after the Revolution. A few months later, Nikolai Efros published a book about the First Studio. It was dedicated to The Cricket on the Hearth but the words Efros used to describe the atmosphere in which Dickens’s production had opened were equally suitable for Twelfth Night: ‘You remember what sort of days those were? On 15 September, 1917, in a letter to Nemirovich-Danchenko, Stanislavsky renounced the stage of the Moscow Art Theatre: I cannot think about any other roles, because I will never be able to do anything, at least in the Moscow Art Theatre. Maybe in some other area or some other place I will be able to rise. Of course I do not mean in other theatres, but in the studios. Othello — free!...1 After the tragedy Stanislavsky had endured with Selo Stepanchikovo, he threw himself into Studio work. He started rehearsing Twelfth Night, a play he had put on at the Society of Art and Literature in 1897. The Studio production of Twelfth Night was played on 25 December 1917, two months to the day after the Revolution. A few months later, Nikolai Efros published a book about the First Studio. It was dedicated to The Cricket on the Hearth but the words Efros used to describe the atmosphere in which Dickens’s production had opened

  9. 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.

  10. 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.

  11. Ultralight repulsive dark matter and BEC

    Science.gov (United States)

    Fan, JiJi

    2016-12-01

    Ultralight scalar dark matter with mass at or below the eV scale and pressure from repulsive self-interaction could form a Bose-Einstein condensate in the early Universe and maybe in galaxies as well. It has been suggested to be a possible solution to the cusp/core problem or even to explain MOND phenomenology. In this paper, I initiate a study of possible self-interactions of ultralight scalar dark matter from the particle physics point of view. To protect its mass, the scalar dark matter is identified as a pseudo Nambu-Goldstone boson (pNGB). Quite a few pNGB models with different potentials such as the QCD axion and the dilaton lead to attractive self-interactions. Yet if an axion is a remnant of a 5D gauged U(1) symmetry, its self-interactions could be repulsive provided the masses and charges of the 5D matter contributing to its potential satisfy certain constraints. Collective symmetry breaking could also lead to a repulsive self-interaction yet with too large a strength that is ruled out by Bullet Cluster constraints. I also discuss cosmological and astrophysical constraints on ultralight repulsive dark matter in terms of a parametrization motivated by particle physics considerations.

  12. 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....

  13. 78 FR 8684 - Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S

    Science.gov (United States)

    2013-02-06

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 222, Inmarsat AMS(R)S AGENCY... RTCA Special Committee 222, Inmarsat AMS(R)S. SUMMARY: The FAA is issuing this notice to advise the public of the twelfth meeting of the RTCA Special Committee 222, Inmarsat AMS(R)S. DATES: The...

  14. Twelfth nerve paresis induced by an unusual posterior fossa arachnoid cyst: case report and literature review.

    Science.gov (United States)

    Tarantino, Roberto; Marruzzo, Daniele; Colistra, Davide; Mancarella, Cristina; Delfini, Roberto

    2014-08-01

    There are only three cases of arachnoid cysts inducing twelfth nerve paresis described in English medical literature. We herein report one more instance. Six weeks after surgery, the patient has almost fully recovered. This case underlines the importance of considering the arachnoid cyst as a possible cause of twelfth nerve paresis.

  15. Causal Factors Influencing Adversity Quotient of Twelfth Grade and Third-Year Vocational Students

    Science.gov (United States)

    Pangma, Rachapoom; Tayraukham, Sombat; Nuangchalerm, Prasart

    2009-01-01

    Problem statement: The aim of this research was to study the causal factors influencing students' adversity between twelfth grade and third-year vocational students in Sisaket province, Thailand. Six hundred and seventy two of twelfth grade and 376 third-year vocational students were selected by multi-stage random sampling techniques. Approach:…

  16. Optimal Cooperative Searching Using Purely Repulsive Interactions

    CERN Document Server

    Tani, Noriyuki P; Quint, David A; Gopinathan, Ajay

    2013-01-01

    Foraging, either solitarily or collectively, is a necessary behavior for survival that is demonstrated by many organisms. Foraging can be collectively optimized by utilizing communication between the organisms. Examples of such communication range from high level strategic foraging by animal groups to rudimentary signaling among unicellular organisms. Here we systematically study the simplest form of communication via long range repulsive interactions between two diffusing Brownian searchers on a one-dimensional lattice. We show that the mean first passage time for either of them to reach a fixed target depends non-monotonically on the range of the interaction and can be optimized for a repulsive range that is comparable to the average spacing between searchers. Our results suggest that even the most rudimentary form of collective searching does in fact lower the search time for the foragers suggesting robust mechanisms for search optimization in cellular communities

  17. Repulsive gravity model for dark energy

    CERN Document Server

    Hohmann, Manuel

    2010-01-01

    We construct a multimetric gravity theory containing N >= 3 copies of standard model matter and a corresponding number of metrics. In the Newtonian limit, this theory generates attractive gravitational forces within each matter sector, and repulsive forces of the same strength between matter from different sectors. This result demonstrates that the recently proven no-go theorem that forbids gravity theories of this type in N = 2 cannot be extended beyond the bimetric case. We apply our theory to cosmology and show that the repulsion between different types of matter may induce the observed accelerating expansion of the universe. In this way dark energy can be explained simply by dark copies of the well-understood standard model.

  18. Repulsive gravity model for dark energy

    Science.gov (United States)

    Hohmann, Manuel; Wohlfarth, Mattias N. R.

    2010-05-01

    We construct a multimetric gravity theory containing N≥3 copies of standard model matter and a corresponding number of metrics. In the Newtonian limit, this theory generates attractive gravitational forces within each matter sector and repulsive forces of the same strength between matter from different sectors. This result demonstrates that the recently proven no-go theorem that forbids gravity theories of this type in N=2 cannot be extended beyond the bimetric case. We apply our theory to cosmology and show that the repulsion between different types of matter may induce the observed accelerating expansion of the universe. In this way dark energy can be explained simply by dark copies of the well-understood standard model.

  19. Implications of Cosmic Repulsion for Gravitational Theory

    CERN Document Server

    Mannheim, P D

    1998-01-01

    In this paper we present a general, model independent analysis of a recently detected apparent cosmic repulsion, and discuss its potential implications for gravitational theory. In particular, we show that a negatively spatially curved universe acts like a diverging refractive medium, to thus naturally cause galaxies to accelerate away from each other. Additionally, we show that it is possible for a cosmic acceleration to only be temporary, with some accelerating universes actually being able to subsequently recontract.

  20. 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.

  1. Energy Analysis and law of universal repulsion

    Science.gov (United States)

    Han, Yongquan

    2012-03-01

    My understanding of energy is as follows: energy is invisible; for this reason, from this perspective it is more accurate to define energy as dark energy. Actually, energy must depend on its carrier. If the carrier is visible, the energy is visible; if the carrier is invisible, the energy is invisible. However, energy does exist, for motion is the everlasting theme. Law of universal repulsion ------All objects in the universe repel each other. Repulsion between two objects is directly proportional to the external energy (mv^2) of their relative motion and indirectly proportional to their relative motion radius (one object is in relative rest, while the other one is in relative motion). Application examples: Suppose a man whose mass is100 kg, runs on the earth at a speed of 10 meters per second. The radius of the earth is 637100 meters. The repulsion between the earth and the man is: F=mv^2/r=0.00157N; if his speed reaches the first cosmic speed ( 7.9 km per second ), then calculate: F=mv^2/r=980N, just overcome the gravity of the earth.

  2. Ultralight Repulsive Dark Matter and BEC

    CERN Document Server

    Fan, JiJi

    2016-01-01

    Ultralight scalar dark matter with mass at or below the eV scale and pressure from repulsive self-interaction could form a Bose-Einstein condensate in the early Universe and maybe in galaxies as well. It has been suggested to be a possible solution to the cusp/core problem or even to explain MOND phenomenology. In this paper, I initiate a study of possible self-interactions of ultralight scalar dark matter from the particle physics point of view. To protect its mass, the scalar dark matter is identified as a pseudo Nambu-Goldstone boson (pNGB). Quite a few pNGB models with different potentials such as the QCD axion and the dilaton lead to attractive self-interactions. Yet if an axion is a remnant of a 5D gauged U(1) symmetry, its self-interactions could be repulsive provided the masses and charges of the 5D matter contributing to its potential satisfy certain constraints. Collective symmetry breaking could also lead to a repulsive self-interaction yet with too large a strength that is ruled out by Bullet Clus...

  3. 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.

    2016-07-01

    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.

  4. Integral equation study of soft-repulsive dimeric fluids

    Science.gov (United States)

    Munaò, Gianmarco; Saija, Franz

    2017-03-01

    We study fluid structure and water-like anomalies of a system constituted by dimeric particles interacting via a purely repulsive core-softened potential by means of integral equation theories. In our model, dimers interact through a repulsive pair potential of inverse-power form with a softened repulsion strength. By employing the Ornstein–Zernike approach and the reference interaction site model (RISM) theory, we study the behavior of water-like anomalies upon progressively increasing the elongation λ of the dimers from the monomeric case (λ =0 ) to the tangent configuration (λ =1 ). For each value of the elongation we consider two different values of the interaction potential, corresponding to one and two length scales, with the aim to provide a comprehensive description of the possible fluid scenarios of this model. Our theoretical results are systematically compared with already existing or newly generated Monte Carlo data: we find that theories and simulations agree in providing the picture of a fluid exhibiting density and structural anomalies for low values of λ and for both the two values of the interaction potential. Integral equation theories give accurate predictions for pressure and radial distribution functions, whereas the temperatures where anomalies occur are underestimated. Upon increasing the elongation, the RISM theory still predicts the existence of anomalies; the latter are no longer observed in simulations, since their development is likely precluded by the onset of crystallization. We discuss our results in terms of the reliability of integral equation theories in predicting the existence of water-like anomalies in core-softened fluids.

  5. 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.

  6. 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

  7. Threshold photodetachment in a repulsive potential

    CERN Document Server

    Lindahl, Anton O; Hultgren, Hannes; Kiyan, Igor Yu; Pegg, David J; Walter, C Wesley; Hanstorp, Dag; 10.1103/PhysRevLett.108.033004

    2012-01-01

    We report on the first experimental observation of a new threshold behavior observed in the 5g partial channel in photodetachment of K-. It arises from the repulsive polarization interaction between the detached electron and the residual K(5g) atom, which has a large negative dipole polarizability. In order to account for the observation in the K(5g) channel, we have developed a semiclassical model that predicts an exponential energy dependence for the cross section. The measurements were made with collinear laser-ion beams and a resonance ionization detection scheme.

  8. Casimir-Polder repulsion: Polarizable atoms, cylinders, spheres, and ellipsoids

    CERN Document Server

    Milton, Kimball A; Pourtolami, Nima; Brevik, Iver

    2012-01-01

    Recently, the topic of Casimir repulsion has received a great deal of attention, largely because of the possibility of technological application. The general subject has a long history, going back to the self-repulsion of a conducting spherical shell and the repulsion between a perfect electric conductor and a perfect magnetic conductor. Recently it has been observed that repulsion can be achieved between ordinary conducting bodies, provided sufficient anisotropy is present. For example, an anisotropic polarizable atom can be repelled near an aperture in a conducting plate. Here we provide new examples of this effect, including the repulsion on such an atom moving on a trajectory nonintersecting a conducting cylinder; in contrast, such repulsion does not occur outside a sphere. Classically, repulsion does occur between a conducting ellipsoid placed in a uniform electric field and an electric dipole. The Casimir-Polder force between an anisotropic atom and an anisotropic dielectric semispace does not exhibit r...

  9. Face aftereffects involve local repulsion, not renormalization.

    Science.gov (United States)

    Storrs, Katherine R; Arnold, Derek H

    2015-01-01

    After looking at a photograph of someone for a protracted period (adaptation), a previously neutral-looking face can take on an opposite appearance in terms of gender, identity, and other attributes-but what happens to the appearance of other faces? Face aftereffects have repeatedly been ascribed to perceptual renormalization. Renormalization predicts that the adapting face and more extreme versions of it should appear more neutral after adaptation (e.g., if the adaptor was male, it and hyper-masculine faces should look more feminine). Other aftereffects, such as tilt and spatial frequency, are locally repulsive, exaggerating differences between adapting and test stimuli. This predicts that the adapting face should be little changed in appearance after adaptation, while more extreme versions of it should look even more extreme (e.g., if the adaptor was male, it should look unchanged, while hyper-masculine faces should look even more masculine). Existing reports do not provide clear evidence for either pattern. We overcame this by using a spatial comparison task to measure the appearance of stimuli presented in differently adapted retinal locations. In behaviorally matched experiments we compared aftereffect patterns after adapting to tilt, facial identity, and facial gender. In all three experiments data matched the predictions of a locally repulsive, but not a renormalizing, aftereffect. These data are consistent with the existence of similar encoding strategies for tilt, facial identity, and facial gender.

  10. Instant transformation of learned repulsion into motivational ‘wanting’

    Science.gov (United States)

    Robinson, Mike J.F.; Berridge, Kent C.

    2013-01-01

    Summary Background Learned cues for pleasant rewards 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 past association with reward outcome. Results We demonstrate that cravings are more than merely the product of accumulated pleasure memories: even a repulsive learned cue for unpleasantness can become suddenly desired via activation of mesocorticolimbic circuitry. Rats learned repulsion toward a Pavlovian cue (briefly-inserted metal lever) that always predicted an unpleasant Dead Sea saltiness sensation. Yet upon first re-encounter in a novel sodium depletion state to promote mesocorticolimbic reactivity (reflected by elevated Fos activation in ventral tegmentum, nucleus accumbens, ventral pallidum, and 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 having never yet tasted intense saltiness itself as anything other than disgusting. Conclusions Instant desire transformation of a learned cue contradicts views that Pavlovian desires are based essentially on previously learned values (e.g., prediction error or temporal difference models). Instead desire is re-computed at re-encounter by integrating Pavlovian information with current brain/physiological state. This powerful brain transformation reversed strong learned revulsion into avid attraction. Applied to addiction, related mesocorticolimbic transformations (e.g., drugs, 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. PMID:23375893

  11. Twelfth International Symposium on Recent Advances in Environmental Health Research.

    Science.gov (United States)

    Tchounwou, Paul B

    2016-05-04

    During the past century, environmental hazards have become a major concern, not only to public health professionals, but also to the society at large because of their tremendous health, socio-cultural and economic impacts. Various anthropogenic or natural factors have been implicated in the alteration of ecosystem integrity, as well as in the development of a wide variety of acute and/or chronic diseases in humans. It has also been demonstrated that many environmental agents, acting either independently or in combination with other toxins, may induce a wide range of adverse health outcomes. Understanding the role played by the environment in the etiology of human diseases is critical to designing cost-effective control/prevention measures. This special issue of International Journal of Environmental Research and Public Health includes the proceedings of the Twelfth International Symposium on Recent Advances in Environmental Health Research. The Symposium provided an excellent opportunity to discuss the scientific advances in biomedical, environmental, and public health research that addresses global environmental health issues.

  12. Photodetachment Microscope with Repulsive Coulomb Field

    CERN Document Server

    Golovinski, P A

    2011-01-01

    Investigation of electronic waves with high coherence in photodetachment of a negative ion gives a physical basis to develop the holographic electronic microscopy with high resolution. The interference pattern is considered in the framework of steady-state wave approach. In semiclassical approximation, an outgoing wave is described by the amplitude slowly varying along a trajectory. Quantum description of electron photodetachment from negative ion is formulated with the help of the inhomogeneous Schr\\"odinger equation. Its asymptotic solution is expressed in terms of the Green function that has exact expression for the homogeneous electric field and the Coulomb field. It is demonstrated that repulsive Coulomb field is effective for magnification of the interference pattern at a short distance from an ion. For the first time, as shown for this case, the interference pattern in asymptotic area can be calculated by means of global semiclassical approximation or, a little more roughly, by simple uniform field app...

  13. A Model of Lexical Attraction and Repulsion

    CERN Document Server

    Beeferman, D; Lafferty, G D; Beeferman, Doug; Berger, Adam; Lafferty, John

    1997-01-01

    This paper introduces new methods based on exponential families for modeling the correlations between words in text and speech. While previous work assumed the effects of word co-occurrence statistics to be constant over a window of several hundred words, we show that their influence is nonstationary on a much smaller time scale. Empirical data drawn from English and Japanese text, as well as conversational speech, reveals that the ``attraction'' between words decays exponentially, while stylistic and syntactic contraints create a ``repulsion'' between words that discourages close co-occurrence. We show that these characteristics are well described by simple mixture models based on two-stage exponential distributions which can be trained using the EM algorithm. The resulting distance distributions can then be incorporated as penalizing features in an exponential language model.

  14. 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.

  15. RGM is a repulsive guidance molecule for retinal axons

    DEFF Research Database (Denmark)

    Monnier, Philippe P; Sierra, Ana; Macchi, Paolo;

    2002-01-01

    the temporal half, is guided by repulsive cues expressed in a graded fashion in the optic tectum, part of the midbrain. Here we report the cloning and functional characterization of a membrane-associated glycoprotein, which we call RGM (repulsive guidance molecule). This molecule shares no sequence homology...

  16. Two-dimensional inverted pendulum using repulsive magnetic levitation

    Energy Technology Data Exchange (ETDEWEB)

    Eirich, Max; Ishino, Yuji; Takasaki, Masaya; Mizuno, Takeshi [Saitama Univ. (Japan). Dept. of Mechanical Engineering

    2010-07-01

    The active control of two-degree-of-freedom motion of the repulsive levitated object (floator) is studied. In this system of permanent magnets, the vertical motions of the rotor are passively supported by repulsive forces between the permanent magnets. The inclination angle is actively stabilized using the motion control of additional magnets. (orig.)

  17. Supermassive galactic centre with repulsive gravity

    CERN Document Server

    Marshall, Trevor W

    2013-01-01

    Repulsive gravity has its origin in the 1939 article of Oppenheimer and Snyder which describes a collapsar, that is an idealized star of non-interacting material (dust) collapsing under its own gravity. The stellar material has a final state resembling a football, that is a significant part of it is concentrated in a thin surface shell. An interior pressure is exerted by the strong gravitational field, equivalent to a negative mass. However, the OS solution has been misunderstood, the shell's position being incorrectly identified with the "event horizon" in black-hole theory. By expressing the OS metric in the preferred frame of harmonic coordinates, as advocated by N. Rosen and V. A. Fock, we obtain a description of the gravitational force field and thereby explain the football-like mass distribution. While half the material is concentrated in a shell occupying a small fraction of the radius, some material is spread throughout the interior, unlike the concentration in a black hole singularity. We deal with t...

  18. Cores in Dwarf Galaxies from Fermi Repulsion

    CERN Document Server

    Randall, Lisa; Unwin, James

    2016-01-01

    We show that Fermi repulsion can lead to cored density profiles in dwarf galaxies for sub-keV fermionic dark matter. We treat the dark matter as a quasi-degenerate self-gravitating Fermi gas and calculate its density profile assuming hydrostatic equilibrium. We find that suitable dwarf galaxy cores of larger than 130 pc can be achieved for fermion dark matter with mass in the range 70 eV - 400 eV. While in conventional dark matter scenarios, such sub-keV thermal dark matter would be excluded by free streaming bounds, the constraints are ameliorated in models with dark matter at lower temperature than conventional thermal scenarios, such as the Flooded Dark Matter model that we have previously considered. Modifying the arguments of Tremaine and Gunn we derive a conservative lower bound on the mass of fermionic dark matter of 70 eV and a stronger lower bound from Lyman-$\\alpha$ clouds of about 470 eV, leading to slightly smaller cores than have been observed. We comment on this result and how the tension is rel...

  19. NAEP Fourth-, Eighth-, and Twelfth-Grade Reading Scores by Gender: 2005, 2007, 2009, 2011, 2013

    Science.gov (United States)

    Klecker, Beverly M.

    2014-01-01

    This paper describes a secondary analysis of the National Assessment of Educational Progress (NAEP) reading scores by gender. Data were national public 4th- and 8th-grade reading scores from composite and subscales for 2005, 2007, 2009, 2011, and 2013. Twelfth-grade scores for composite and literary experience from 2005, 2009, and 2013 and gain…

  20. 76 FR 79754 - Twelfth Meeting: RTCA Special Committee 220, Automatic Flight Guidance and Control

    Science.gov (United States)

    2011-12-22

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 220, Automatic Flight Guidance and Control AGENCY: Federal Aviation Administration (FAA), U.S. Department of Transportation (DOT). ACTION... Return to general plenary meeting Review of WG 2 status--progress, issues and plan Review of WG 3...

  1. 78 FR 16031 - Twelfth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems...

    Science.gov (United States)

    2013-03-13

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 225, Rechargeable Lithium Battery and Battery Systems--Small and Medium Size AGENCY: Federal Aviation Administration (FAA), U.S... Lithium Battery and Battery Systems--Small and Medium Size. SUMMARY: The FAA is issuing this notice to...

  2. Attraction-repulsion coupled and energy conserved universe

    CERN Document Server

    Li, Ti-Pei

    2011-01-01

    The discovery of an accelerating cosmic expansion rate implies that, in addition to the attractive gravity of matter, there exist in our universe some other form of energy (dark energy or cosmological constant) producing a repulsive force. The natural interpretation of dark energy is the vacuum energy. However, the density of vacuum energy expected by the quantum field theory is 120 orders of magnitude larger than what allowed by cosmological observations, which is called the cosmological constant problem and remains one of the most significant unsolved problems in fundamental physics. Here we show that the huge discrepancy between theoretical expectation and observational data can be resolved by assuming that our universe is an attraction-repulsion coupled system with energy conservation, and that the pre-inflation vacuum is in balance between attraction and repulsion (a flat Minkowski spacetime, not de Sitter or anti de Sitter). The attraction-repulsion coupling picture can also easily explain why both kind...

  3. Design and analysis of repulsive electrostatic driven MEMS actuators

    Science.gov (United States)

    Yao, Jun; Hu, Fangrong; Cai, Dongmei; Jiang, Wenhan

    2009-02-01

    For many astronomical systems, Adaptive Optics (AO) plays an important role. Here, we report some preliminary studies on MEMS (Micro-Electro-Mechanical-System) Project for micro actuators in AO applications at the Institute of Optics and Electronics, Chinese Academy of Science. This paper presents a few MEMS actuators based on repulsive electrostatic driven mechanism, which can achieve large out-of-plane strokes through eliminating the electrostatic pull-in effect. Design principles, including the layout and the physical dimension of electrodes, and FEA models are illustrated; it provides helpful guidance for designing electrostatic repulsive actuators for being implemented in Deformable Mirrors (DMs). Some repulsive electrostatic driven micro actuators are given, the analysis focus on the displacement versus applied voltage and resonant frequency. Repulsive electrostatic driven actuators can achieve large strokes and high resonant frequencies, they meet the important requirements for DMs.

  4. Repulsive Magnetic Levitation Systems Using Motion Control of Magnets

    OpenAIRE

    水野, 毅; 石野, 裕二; 荒木, 獻次; 大内, 泰平

    1995-01-01

    Repulsive magnetic levitation systems with magnets driven by actuators were studied in this paper. In one system, a levitation magnet was driven in the direction of repulsive force to control the position and vibration of the levitated object. In another, a levitation magnet was moved in the lateral directions to stabilize the system in the manner of an inverted pendulum. The first type was studied experimentally with an experimental setup using a magnetostrictive actuator. The damping charac...

  5. An anisotropic hydrogel with electrostatic repulsion between cofacially aligned nanosheets

    Science.gov (United States)

    Liu, Mingjie; Ishida, Yasuhiro; Ebina, Yasuo; Sasaki, Takayoshi; Hikima, Takaaki; Takata, Masaki; Aida, Takuzo

    2015-01-01

    Machine technology frequently puts magnetic or electrostatic repulsive forces to practical use, as in maglev trains, vehicle suspensions or non-contact bearings. In contrast, materials design overwhelmingly focuses on attractive interactions, such as in the many advanced polymer-based composites, where inorganic fillers interact with a polymer matrix to improve mechanical properties. However, articular cartilage strikingly illustrates how electrostatic repulsion can be harnessed to achieve unparalleled functional efficiency: it permits virtually frictionless mechanical motion within joints, even under high compression. Here we describe a composite hydrogel with anisotropic mechanical properties dominated by electrostatic repulsion between negatively charged unilamellar titanate nanosheets embedded within it. Crucial to the behaviour of this hydrogel is the serendipitous discovery of cofacial nanosheet alignment in aqueous colloidal dispersions subjected to a strong magnetic field, which maximizes electrostatic repulsion and thereby induces a quasi-crystalline structural ordering over macroscopic length scales and with uniformly large face-to-face nanosheet separation. We fix this transiently induced structural order by transforming the dispersion into a hydrogel using light-triggered in situ vinyl polymerization. The resultant hydrogel, containing charged inorganic structures that align cofacially in a magnetic flux, deforms easily under shear forces applied parallel to the embedded nanosheets yet resists compressive forces applied orthogonally. We anticipate that the concept of embedding anisotropic repulsive electrostatics within a composite material, inspired by articular cartilage, will open up new possibilities for developing soft materials with unusual functions.

  6. 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.

  7. 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.

  8. Study of Electromagnetic Repulsion Switch to High Speed Reclosing and Recover Time Characteristics of Superconductor

    Science.gov (United States)

    Koyama, Tomonori; Kaiho, Katsuyuki; Yamaguchi, Iwao; Yanabu, Satoru

    Using a high-temperature superconductor, we constructed and tested a model superconducting fault current limiter (SFCL). The superconductor and vacuum interrupter as the commutation switch were connected in parallel using a bypass coil. When the fault current flows in this equipment, the superconductor is quenched and the current is then transferred to the parallel coil due to the voltage drop in the superconductor. This large current in the parallel coil actuates the magnetic repulsion mechanism of the vacuum interrupter and the current in the superconductor is broken. Using this equipment, the current flow time in the superconductor can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of the parallel coil. This system has many merits. So, we introduced to electromagnetic repulsion switch. There is duty of high speed re-closing after interrupting fault current in the electrical power system. So the SFCL should be recovered to superconducting state before high speed re-closing. But, superconductor generated heat at the time of quench. It takes time to recover superconducting state. Therefore it is a matter of recovery time. In this paper, we studied recovery time of superconductor. Also, we proposed electromagnetic repulsion switch with reclosing system.

  9. Enhanced compressibility due to repulsive interaction in the Harper model

    Science.gov (United States)

    Kraus, Yaacov E.; Zilberberg, Oded; Berkovits, Richard

    2014-04-01

    We study the interplay between a repulsive interaction and an almost staggered on-site potential in one dimension. Specifically, we address the Harper model for spinless fermions with nearest-neighbor repulsion, close to half filling. Using the density matrix renormalization group, we find that, in contrast to standard behavior, the system becomes more compressible as the repulsive interaction is increased. By deriving a low-energy effective model, we unveil the effect of interactions using mean-field analysis: The density of a narrow band around half filling is anticorrelated with the on-site potential, whereas the density of lower occupied bands follows the potential and strengthens it. As a result, the states around half filling are squeezed by the background density, their band becomes flatter, and the compressibility increases.

  10. Of Matter Less Repulsive than a Cosmological Constant

    CERN Document Server

    Cornish, N J; Cornish, Neil J.; Starkman, Glenn D.

    1998-01-01

    The case grows ever stronger that the average density of matter, ordinary and dark, is less than the critical density required for a flat universe. However, most of determinations of the mass density have been dynamical, hence sensitive only to matter which is clustered at or below the scale of the observed dynamical systems. The density may still be critical if there is a dark matter component which is relatively smooth on the scales of galaxies or clusters. Thoughts on this matter have focused on the possibility of an effective cosmological constant or vacuum energy. In this letter we examine an alternative possibility - that there is a second component to the dark matter which has a repulsive self-interaction. We show that given even very weak self-repulsion, this dark matter would remain unclustered. While this repulsive alternative is perhaps aptly named, it is arguably at least as palatable as a cosmological constant.

  11. Charged membrane as a source for repulsive gravity

    CERN Document Server

    Belinski, V; Paolino, A

    2008-01-01

    We demonstrate an alternative (with respect to the ones existing in literature) and more habitual for physicists derivation of exact solution of the Einstein-Maxwell equations for the motion of a charged spherical membrane with tangential tension. We stress that the physically acceptable range of parameters for which the static and stable state of the membrane producing the Reissner-Nordstrom (RN) repulsive gravity effect exists. The concrete realization of such state for the Nambu-Goto membrane is described. The point is that membrane are able to cut out the central naked singularity region and at the same time to join in appropriate way the RN repulsive region. As result we have a model of an everywhere-regular material source exhibiting a repulsive gravitational force in the vicinity of its surface: this construction gives a more sensible physical status to the RN solution in the naked singularity case.

  12. Introduction and session summaries for the proceedings of the twelfth symposium on biotechnology fuels and chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, E. (Oak Ridge National Lab., TN (USA)); Wyman, C.E. (Solar Energy Research Inst., Golden, CO (USA))

    1990-01-01

    This Twelfth Symposium on Biotechnology for Fuels and Chemicals continues to provide an annual forum for researchers from industry, universities, and government laboratories to exchange information on recent developments in emerging bioprocessing technologies. As in the past, innovative processing concepts are stressed that are in the early stages of development. The meeting began with a session on Thermal, Chemical, and Biological Processing, followed by two sessions on Applied Biological Research. Next, topics in Bioengineering Research were presented, and a special session on Biotechnology, Bioengineering, and the Solution of Environmental Problems concluded the Twelfth Symposium. Both presentations and posters provided information exchange among meeting participants, and several discussion groups were organized to consider special topics of interest to the meeting participants. This paper presents a brief description of the discussions.

  13. Repulsive Casimir force between silicon dioxide and superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Phan, Anh D. [Department of Physics, University of South Florida, Tampa, Florida (United States); Viet, N.A. [Institute of Physics, Badinh, Hanoi (Viet Nam)

    2012-06-15

    We present a detailed investigation of the Casimir interaction between the superconductor Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (BSCCO) and silicon dioxide with bromobenzene present in between. We found that the dispersion force is repulsive and the magnitude of the force can be changed by varying the thickness of the object and the temperature. The repulsive force would provide a method to deal with stiction problems and provide much significant from the practical point of view. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Comparison of chiral metamaterial designs for repulsive Casimir force

    Science.gov (United States)

    Zhao, R.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2010-06-01

    In our previous work [R. Zhao, J. Zhou, Th. Koschny, E. N. Economou, and C. M. Soukoulis, Phys. Rev. Lett. 103, 103602 (2009)], we found that repulsive Casimir forces could be realized by using chiral metamaterials if the chirality is strong enough. In this work, we check four different chiral metamaterial designs (i.e., Twisted-Rosettes, Twisted-Crosswires, Four-U-SRRs, and Conjugate-Swastikas) and find that the designs of Four-U-SRRs and Conjugate-Swastikas are the most promising candidates to realize repulsive Casimir force because of their large chirality and the small ratio of structure length scale to resonance wavelength.

  15. Comparison of Chiral Metamaterial Designs for Repulsive Casimir Force

    OpenAIRE

    Zhao, R.; Koschny, Th.; Economou, E. N.; C M Soukoulis

    2009-01-01

    In our previous work [Phys. Rev. Lett. 103, 103602 (2009)], we found that repulsive Casimir forces could be realized by using chiral metamaterials if the chirality is strong enough. In this work, we check four different chiral metamaterial designs (i.e., Twisted-Rosettes, Twisted-Crosswires, Four-U-SRRs, and Conjugate-Swastikas) and find that the designs of Four-U-SRRs and Conjugate-Swastikas are the most promising candidates to realize repulsive Casimir force because of their large chirality...

  16. 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.

  17. 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 ...

  18. Spontaneous symmetry breaking in vortex systems with two repulsive lengthscales

    Science.gov (United States)

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

    2015-01-01

    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. PMID:26492969

  19. Fast Electron Repulsion Integrals for Molecular Coulomb Sturmians

    DEFF Research Database (Denmark)

    Avery, James Emil

    2013-01-01

    of hyperspherical harmonics. A rudimentary software library has been implemented and preliminary benchmarks indicate very good performance: On average 40 ns, or approximately 80 clock cycles, per electron repulsion integral. This makes molecular Coulomb Sturmians competitive with Gaussian type orbitals in terms...

  20. 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.

  1. Homogeneous cooling with repulsive and attractive long-range interactions

    NARCIS (Netherlands)

    Müller, M.K; Masami, Nakagawa; Luding, Stefan

    2009-01-01

    In granular matter, consisting of discrete particles, long-range interactions imply that each of the particles is interacting with all others. For many charged granular materials with Coulomb repulsion or large-scale gravitationally attractive systems, a Molecular Dynamics environment is developed.

  2. 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 a therm...

  3. Repulsive Casimir force from fractional Neumann boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lim, S.C. [Faculty of Engineering, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia)], E-mail: sclim@mmu.edu.my; Teo, L.P. [Faculty of Information Technology, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia); Department of Applied Mathematics, Faculty of Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor Darul Ehsan (Malaysia)], E-mail: lpteo@mmu.edu.my

    2009-08-17

    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.

  4. Electrostatic repulsive out-of-plane actuator using conductive substrate.

    Science.gov (United States)

    Wang, Weimin; Wang, Qiang; Ren, Hao; Ma, Wenying; Qiu, Chuankai; Chen, Zexiang; Fan, Bin

    2016-10-07

    A pseudo-three-layer electrostatic repulsive out-of-plane actuator is proposed. It combines the advantages of two-layer and three-layer repulsive actuators, i.e., fabrication requirements and fill factor. A theoretical model for the proposed actuator is developed and solved through the numerical calculation of Schwarz-Christoffel mapping. Theoretical and simulated results show that the pseudo-three-layer actuator offers higher performance than the two-layer and three-layer actuators with regard to the two most important characteristics of actuators, namely, driving force and theoretical stroke. Given that the pseudo-three-layer actuator structure is compatible with both the parallel-plate actuators and these two types of repulsive actuators, a 19-element two-layer repulsive actuated deformable mirror is operated in pseudo-three-layer electrical connection mode. Theoretical and experimental results demonstrate that the pseudo-three-layer mode produces a larger displacement of 0-4.5 μm for a dc driving voltage of 0-100 V, when compared with that in two-layer mode.

  5. "Magic" surface clustering of borazines driven by repulsive intermolecular forces.

    Science.gov (United States)

    Kervyn, Simon; Kalashnyk, Nataliya; Riello, Massimo; Moreton, Ben; Tasseroul, Jonathan; Wouters, Johan; Jones, Tim S; De Vita, Alessandro; Costantini, Giovanni; Bonifazi, Davide

    2013-07-15

    It's a kind of magic: Hydroxy pentaaryl borazine molecules self-assemble into small clusters (see structure) on Cu(111) surfaces, whereas with symmetric hexaaryl borazine molecules large islands are obtained. Simulations indicate that the observed "magic" cluster sizes result from long-range repulsive Coulomb forces arising from the deprotonation of the B-OH groups of the hydroxy pentaaryl borazine.

  6. Monodisperse Clusters in Charged Attractive Colloids: Linear Renormalization of Repulsion.

    Science.gov (United States)

    Růžička, Štěpán; Allen, Michael P

    2015-08-11

    Experiments done on polydisperse particles of cadmium selenide have recently shown that the particles form spherical isolated clusters with low polydispersity of cluster size. The computer simulation model of Xia et al. ( Nat. Nanotechnol. 2011 , 6 , 580 ) explaining this behavior used a short-range van der Waals attraction combined with a variable long-range screened electrostatic repulsion, depending linearly on the volume of the clusters. In this work, we term this dependence "linear renormalization" of the repulsive term, and we use advanced Monte Carlo simulations to investigate the kinetically slowed down phase separation in a similar but simpler model. We show that amorphous drops do not dissolve and crystallinity evolves very slowly under linear renormalization, and we confirm that low polydispersity of cluster size can also be achieved using this model. The results indicate that the linear renormalization generally leads to monodisperse clusters.

  7. Modeling and strain gauging of eddy current repulsion deicing systems

    Science.gov (United States)

    Smith, Samuel O.

    1993-01-01

    Work described in this paper confirms and extends work done by Zumwalt, et al., on a variety of in-flight deicing systems that use eddy current repulsion for repelling ice. Two such systems are known as electro-impulse deicing (EIDI) and the eddy current repulsion deicing strip (EDS). Mathematical models for these systems are discussed for their capabilities and limitations. The author duplicates a particular model of the EDS. Theoretical voltage, current, and force results are compared directly to experimental results. Dynamic strain measurements results are presented for the EDS system. Dynamic strain measurements near EDS or EIDI coils are complicated by the high magnetic fields in the vicinity of the coils. High magnetic fields induce false voltage signals out of the gages.

  8. Repulsive Magnetic Bearing Using a Piezoelectric Actuator for Stabilization

    Science.gov (United States)

    Mizuno, Takeshi; Aizawa, Mitsunori

    A repulsive magnetic bearing system equipped with a piezoelectric actuator for the motion control of permanent magnets is studied experimentally. In this system, the radial motions of the rotor are passively supported by repulsive forces between permanent magnets. The motion in the axial direction is stabilized by moving the permanent magnets for radial suspension with a piezoelectric actuator. In the experiments, a piezoelectric actuator with a stroke of 200µm was installed first. PD and I-PD controllers were applied to achieve levitation without any mechanical contact. It was experimentally shown that the dynamic characteristics of the levitation system could be adjusted by pole assignment. Next the actuator was replaced by an actuator with a stoke of 90µm. Experimental results demonstrated that the rotor can follow stepwise command signal whose magnitude was within ±20µm.

  9. Holographic superfluid flows with a localized repulsive potential

    CERN Document Server

    Ishibashi, Akihiro; Okamura, Takashi

    2016-01-01

    We investigate a holographic model of superfluid flows with an external repulsive potential. When the strength of the potential is sufficiently weak, we analytically construct two steady superfluid flow solutions. As the strength of the potential is increased, the two solutions merge into a single critical solution at a critical strength, and then disappear above the critical value, as predicted by a saddle-node bifurcation theory. We also analyze the spectral function of fluctuations around the solutions under a certain decoupling approximation.

  10. Short distance repulsion in 3 nucleon forces from perturbative QCD

    OpenAIRE

    Aoki, Sinya; Balog, Janos; Weisz, Peter

    2011-01-01

    We investigate the short distance behavior of 3 nucleon forces (3NF) defined through Nambu--Bethe--Salpeter wave functions, using the operator product expansion(OPE) and calculating anomalous dimensions of 9--quark operators in perturbative QCD. As is the case of NN forces previously considered, we show that 3NF have repulsions at short distance at 1--loop, which becomes exact in the short distance limit thanks to the asymptotic freedom of QCD. Moreover these behaviors are universal in the se...

  11. 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.

  12. A cellular automata evacuation model considering friction and repulsion

    Institute of Scientific and Technical Information of China (English)

    SONG Weiguo; YU Yanfei; FAN Weicheng; Zhang Heping

    2005-01-01

    There exist interactions among pedestrians and between pedestrian and environment in evacuation. These interactions include attraction, repulsion and friction that play key roles in human evacuation behaviors, speed and efficiency. Most former evacuation models focus on the attraction force, while repulsion and friction are not well modeled. As a kind of multi-particle self-driven model, the social force model introduced in recent years can represent those three forces but with low simulation efficiency because it is a continuous model with complex rules. Discrete models such as the cellular automata model and the lattice gas model have simple rules and high simulation efficiency, but are not quite suitable for interactions' simulation. In this paper, a new cellular automata model based on traditional models is introduced in which repulsion and friction are modeled quantitatively. It is indicated that the model can simulate some basic behaviors, e.g.arching and the "faster-is-slower" phenomenon, in evacuation as multi-particle self-driven models, but with high efficiency as the normal cellular automata model and the lattice gas model.

  13. Repulsive Casimir forces with finite-thickness slabs

    Science.gov (United States)

    Zhao, R.; Koschny, Th.; Economou, E. N.; Soukoulis, C. M.

    2011-02-01

    We use the extended Lifshitz theory to study the behaviors of the Casimir forces between finite-thickness effective medium slabs. We first study the interaction between a semi-infinite Drude metal and a finite-thickness magnetic slab with or without substrate. For no substrate, the large distance d dependence of the force is repulsive and goes as 1/d5; for the Drude metal substrate, a stable equilibrium point appears at an intermediate distance that can be tuned by the thickness of the slab. We then study the interaction between two identical chiral metamaterial slabs, with and without substrate. For no substrate, the finite thickness of the slabs D does not significantly influence the repulsive character of the force at short distances, while the attractive character at large distances becomes weaker and behaves as 1/d6; for the Drude metal substrate, the finite thickness of the slabs D does not influence the repulsive force too much at short distances until D=0.05λ0.

  14. Molecular analysis of axon repulsion by the notochord.

    Science.gov (United States)

    Anderson, Christopher N G; Ohta, Kunimasa; Quick, Marie M; Fleming, Angeleen; Keynes, Roger; Tannahill, David

    2003-03-01

    During development of the amniote peripheral nervous system, the initial trajectory of primary sensory axons is determined largely by the action of axon repellents. We have shown previously that tissues flanking dorsal root ganglia, the notochord lying medially and the dermamyotomes lying laterally, are sources of secreted molecules that prevent axons from entering inappropriate territories. Although there is evidence suggesting that SEMA3A contributes to the repellent activity of the dermamyotome, the nature of the activity secreted by the notochord remains undetermined. We have employed an expression cloning strategy to search for axon repellents secreted by the notochord, and have identified SEMA3A as a candidate repellent. Moreover, using a spectrum of different axon populations to assay the notochord activity, together with neuropilin/Fc receptor reagents to block semaphorin activity in collagen gel assays, we show that SEMA3A probably contributes to notochord-mediated repulsion. Sympathetic axons that normally avoid the midline in vivo are also repelled, in part, by a semaphorin-based notochord activity. Although our results implicate semaphorin signalling in mediating repulsion by the notochord, repulsion of early dorsal root ganglion axons is only partially blocked when using neuropilin/Fc reagents. Moreover, retinal axons, which are insensitive to SEMA3A, are also repelled by the notochord. We conclude that multiple factors act in concert to guide axons in this system, and that further notochord repellents remain to be identified.

  15. Casimir-Polder repulsion: Three-body effects

    CERN Document Server

    Milton, Kimball A; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen A; Buhmann, Stefan Yoshi; Scheel, Stefan

    2015-01-01

    In this paper we study an archetypical scenario in which repulsive Casimir-Polder forces between an atom or molecule and two macroscopic bodies can be achieved. This is an extension of previous studies of the interaction between a polarizable atom and a wedge, in which repulsion occurs if the atom is sufficiently anisotropic and close enough to the symmetry plane of the wedge. A similar repulsion occurs if such an atom passes a thin cylinder or a wire. An obvious extension is to compute the interaction between such an atom and two facing wedges, which includes as a special case the interaction of an atom with a conducting screen possessing a slit, or between two parallel wires. To this end we further extend the electromagnetic multiple-scattering formalism for three-body interactions. To test this machinery we reinvestigate the interaction of a polarizable atom between two parallel conducting plates. In that case, three-body effects are shown to be small, and are dominated by three- and four-scattering terms....

  16. When do we need attractive-repulsive intermolecular potentials?

    Energy Technology Data Exchange (ETDEWEB)

    Venkattraman, Ayyaswamy [School of Engineering, University of California, Merced, Merced, CA 95343 (United States)

    2014-12-09

    The role of attractive-repulsive interactions in direct simulation Monte Carlo (DSMC) simulations is studied by comparing with traditional purely repulsive interactions. The larger collision cross section of the long-range LJ potential is shown to result in a higher collision frequency and hence a lower mean free path, by at least a factor of two, for given conditions. This results in a faster relaxation to equilibrium as is shown by comparing the fourth and sixth moments of the molecular velocity distribution obtained using 0-D DSMC simulations. A 1-D Fourier-Couette flow with a large temperature and velocity difference between the walls is used to show that matching transport properties will result in identical solutions using both LJPA and VSS models in the near-continuum regime. However, flows in the transitional regime with Knudsen number, Kn ∼ 0.5 show a dependence on the intermolecular potential in spite of matching the viscosity coefficient due to differences in the collision frequency. Attractive-repulsive potentials should be used when both transport coefficients and collision frequencies should be matched.

  17. Twelfth grade follow-up of the effectiveness of a middle school-based substance abuse prevention program.

    Science.gov (United States)

    Shope, J T; Copeland, L A; Kamp, M E; Lang, S W

    1998-01-01

    A twelfth-grade follow-up afforded the opportunity to assess the long-term effects of substance abuse prevention delivered in sixth and seventh grades. A social pressures resistance skills curriculum implemented by classroom teachers had been evaluated with short-term positive results previously reported. Students completed self-administered questionnaires at sixth grade pre- and posttests, and at seventh and twelfth-grade posttests. Curriculum group students received lessons on alcohol, tobacco (cigarettes and smokeless), marijuana, and cocaine, which were later incorporated into the Michigan Model for Comprehensive School Health Education. This evaluation used data from 262 students who completed all four questionnaires and who received the complete two-year intervention or no intervention. Repeated measures analyses of variance demonstrated that significant effects evident at seventh grade for alcohol use and misuse, as well as cigarette, cocaine, and other drug use were generally not maintained through twelfth grade. Ongoing reinforcement of effective prevention is recommended.

  18. Qinghai Newly Adds 1 Million Tonnes of Copper and 2 Million Tonnes of Lead Zinc In the “Twelfth Five Year Plan” period

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The reporter recently learned from Qinghai Province Geological Prospecting Bureau that Qinghai’s geological prospecting for the"Twelfth Five Year Plan"period had made significant breakthroughs,and newly submitted58 orefields.It has been learned that,during the"Twelfth

  19. Interbilayer repulsion forces between tension-free lipid bilayers from simulation

    NARCIS (Netherlands)

    Smirnova, Y. G.; Aeffner, S.; Risselada, H. J.; Salditt, T.; Marrink, S. J.; Mueller, M.; Knecht, V.

    2013-01-01

    Here we report studies on biologically important intermembrane repulsion forces using molecular dynamics (MD) simulations and experimental (osmotic stress) investigations of repulsion forces between 1-palmitoyl-2-oleyl-sn-glycero-3-phosphocholine bilayers. We show that the repulsion between tension-

  20. The Roots of Fencing from the Twelfth to the Fourteenth Centuries in the French Language Area

    Directory of Open Access Journals (Sweden)

    Dupuis Olivier

    2015-05-01

    Full Text Available This article offers a partial overview on fencing, as recognized through archive records, as well as French epics and romances from the twelfth to the early fourteenth century. In the twelfth century, fencing was only attested through knightly vocabulary as a way to describe actions performed during single combats involving a combination of shield and another weapon, most commonly a sword. Fencing was progressively dissociated from the knightly arts and there were even few mentions of its use by common people. There are archive records from the thirteenth century of individuals bearing the nickname “fencer”, although there is rarely enough context to be certain that they were really practicing the art. At the end of the thirteenth century, archives and narrative fiction show an established fashion for a certain form of fencing with a short round shield, the buckler. This is clearly established in London where surviving manuscripts include many regulations on fencing, however the fashion was also spread in the continent, even though it seems to be less documented.

  1. Before Grosseteste: Roger of Hereford and calendar reform in eleventh- and twelfth-century England.

    Science.gov (United States)

    Moreton, J.

    1995-12-01

    The existence in the West Country - that area of England that is nearest to the Welsh border - in the eleventh and twelfth centuries of a group of scholars with scientific interests has long been recognized. The part that compotus played in the development of these interests was noted, but it has not been studied in any detail. It was here that a proposal for a reform of the ecclesiastical calendar, based not only on the reckoning traditionally attributed to Dionysius Exiguus but relating also to observed phenomena, was arrived at, then verified with the use of newly available scientific ideas from Arabic sources. One reason for the neglect of this topic is that three very important computistical treatises - the eleventh-century Compotus of Gerland and those of Roger of Hereford and the writer who has been identified with a certain "Constabularius", both from the twelfth century - have not been printed. The aim of this article is to explain why the study of compotus flourished in the West Country and then to examine its development in these and related treatises.

  2. 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.

  3. Repulsive Casimir forces with finite-thickness slabs

    OpenAIRE

    Zhao, R.; Koschny, Th.; Economou, E. N.; C M Soukoulis

    2010-01-01

    We use the extended Lifshitz theory to study the behaviors of the Casimir forces between finite-thickness effective medium slabs. We first study the interaction between a semi-infinite Drude metal and a finite-thickness magnetic slab with or without substrate. For no substrate, the large distance $d$ dependence of the force is repulsive and goes as $1/d^5$; for the Drude metal substrate, a stable equilibrium point appears at an intermediate distance which can be tuned by the thickness of the ...

  4. Micro-electromechanical memory bit based on magnetic repulsion

    Science.gov (United States)

    López-Suárez, Miquel; Neri, Igor

    2016-09-01

    A bistable micro-mechanical system based on magnetic repulsion is presented exploring its applicability as memory unit where the state of the bit is encoded in the rest position of a deflected cantilever. The non-linearity induced on the cantilever can be tuned through the magnetic interaction intensity between the cantilever magnet and the counter magnet in terms of geometrical parameters. A simple model provides a sound prediction of the behavior of the system. Finally, we measured the energy required to store a bit of information on the system that, for the considered protocols, is bounded by the energy barrier separating the two stable states.

  5. 76 FR 17473 - Twelfth Meeting: RTCA Special Committee 214: Working Group 78: Standards for Air Traffic Data...

    Science.gov (United States)

    2011-03-29

    ... Federal Aviation Administration Twelfth Meeting: RTCA Special Committee 214: Working Group 78: Standards...: Notice of RTCA Special Committee 214: Working Group 78: Standards for Air Traffic Data Communication... Committee 214: Working Group 78: Standards for Air Traffic Data Communication Services. DATES: The...

  6. Comparison of Political Attitudes of German and American Twelfth Year Students: Perspectives on the Rights of Individuals.

    Science.gov (United States)

    Hepburn, Mary A.

    A broad survey of democratic political attitudes of United States and West German students was developed jointly by the Governmental Education Division of the Vinson Institute of Government at the University of Georgia and the Bundeszentrale fur politische Bildung in Bonn. This survey sought to probe twelfth-year students' attitudes toward…

  7. 75 FR 11116 - Certain Pasta from Italy: Notice of Amended Final Results of the Twelfth Antidumping Duty...

    Science.gov (United States)

    2010-03-10

    ... Results of the Twelfth Administrative Review, 75 FR 6352 (February 9, 2010) (Final Results). We are... Antidumping Duty Changed Circumstances Review and Revocation, in Part, 74 FR 41120 (August 14, 2009). The... clarified its ``automatic assessment''' regulation on May 6, 2003 (68 FR 23954). This clarification...

  8. Exploring the Effect of Reader Response Plus on Twelfth Grade Students with Disabilities' Reading Comprehension and Attitudes toward Reading

    Science.gov (United States)

    Granger, Noelle; Black, Alison; Miller, Jane

    2007-01-01

    The purpose of the study was to examine how reader response journals followed by classroom discussion ("Reader Response Plus") contributed to students' reading comprehension and to their attitudes toward reading. The study was conducted in a rural school in upstate New York. The twelfth grade class that participated in the study…

  9. The Twelfth US Air Force. Tactical and Operational Innovations in the Mediterranean Theater of Operations, 1943-1944

    Science.gov (United States)

    2007-02-01

    Husky was a strategic success, contributing to the resignation of Italian dictator Benito Mussolini on 25 July 1943, and the 30 OPERATION HUSKY AND... Mussolini and the surrender of Italy. The Italian capitulation forced the Germans to defend Italy alone with overstretched forces. The Twelfth Air Force

  10. 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.

  11. Interaction Versus Entropic Repulsion for Low Temperature Ising Polymers

    Science.gov (United States)

    Ioffe, Dmitry; Shlosman, Senya; Toninelli, Fabio Lucio

    2015-03-01

    Contours associated to many interesting low-temperature statistical mechanics models (2D Ising model, (2+1)D SOS interface model, etc) can be described as self-interacting and self-avoiding walks on . When the model is defined in a finite box, the presence of the boundary induces an interaction, that can turn out to be attractive, between the contour and the boundary of the box. On the other hand, the contour cannot cross the boundary, so it feels entropic repulsion from it. In various situations of interest (in Caputo et al. Ann. Probab., arXiv:1205.6884, J. Eur. Math. Soc., arXiv:1302.6941, arXiv:1406.1206, Ioffe and Shlosman, in preparation), a crucial technical problem is to prove that entropic repulsion prevails over the pinning interaction: in particular, the contour-boundary interaction should not modify significantly the contour partition function and the related surface tension should be unchanged. Here we prove that this is indeed the case, at least at sufficiently low temperature, in a quite general framework that applies in particular to the models of interest mentioned above.

  12. An improved density matrix functional by physically motivated repulsive corrections.

    Science.gov (United States)

    Gritsenko, Oleg; Pernal, Katarzyna; Baerends, Evert Jan

    2005-05-22

    An improved density matrix functional [correction to Buijse and Baerends functional (BBC)] is proposed, in which a hierarchy of physically motivated repulsive corrections is employed to the strongly overbinding functional of Buijse and Baerends (BB). The first correction C1 restores the repulsive exchange-correlation (xc) interaction between electrons in weakly occupied natural orbitals (NOs) as it appears in the exact electron pair density rho(2) for the limiting two-electron case. The second correction C2 reduces the xc interaction of the BB functional between electrons in strongly occupied NOs to an exchange-type interaction. The third correction C3 employs a similar reduction for the interaction of the antibonding orbital of a dissociating molecular bond. In addition, C3 applies a selective cancellation of diagonal terms in the Coulomb and xc energies (not for the frontier orbitals). With these corrections, BBC still retains a correct description of strong nondynamical correlation for the dissociating electron pair bond. BBC greatly improves the quality of the BB potential energy curves for the prototype few-electron molecules and in several cases BBC reproduces very well the benchmark ab initio potential curves. The average error of the self-consistent correlation energies obtained with BBC3 for prototype atomic systems and molecular systems at the equilibrium geometry is only ca. 6%.

  13. Forecast of Grain Production of China during the Twelfth Five-Year Plan Period

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    According to the latest revised agricultural economic statistical data in China Statistical Yearbook-2010,by selecting and establishing the square root-treated grey model,the empirical analysis and forecast research on the grain output of China from 2011 to 2015 are conducted.The results show that the grain output of China in 2011 will reach 557.739 million tons,and it will break through 600 million tons at 605.617 million tons in 2015.The persistent and stable grain output will ensure that the national economy develops in normal during the twelfth five-year plan period and remit the world grain crisis efficiently;meanwhile,the problem of exorbitant grain prices should be remitted in some level.

  14. 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.

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

    DEFF Research Database (Denmark)

    Thébault, E.; Finlay, C. C.; Toh, H.

    2015-01-01

    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 maintained since 1968 by a working group of volunteer scientists from several international institutions......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...... and Geophysics/Union Internationale de Géodésie et Géophysique (IUGG/UIGG), an “international organization dedicated to advancing, promoting, and communicating knowledge of the Earth system, its space environment, and the dynamical processes causing change” (http://www.iugg.org/)....

  16. Double asymptotic expansion of three-center electronic repulsion integrals

    Science.gov (United States)

    Alvarez-Ibarra, A.; Köster, A. M.

    2013-07-01

    A double asymptotic expansion for the evaluation of three-center electron repulsion integrals (ERIs) in the long-range limit is presented. For the definition of this limit, a natural division of space based on the atomic coordinates and basis function exponents in utilized. The resulting analytical expression for the calculation of three-center ERIs in the long-range limit are implemented in the density functional theory program deMon2k. Validation and benchmark calculations of n-alkanes, hydrogen saturated graphene sheets and hydrogen saturated diamond blocks are discussed. It is shown that for a sufficient large number of long-range ERIs, the linear scaling regime is reached.

  17. General relativistic polytropes with a repulsive cosmological constant

    CERN Document Server

    Stuchlík, Zdeněk; Novotný, Jan

    2016-01-01

    Spherically symmetric equilibrium configurations of perfect fluid obeying a polytropic equation of state are studied in spacetimes with a repulsive cosmological constant. The configurations are specified in terms of three parameters---the polytropic index $n$, the ratio of central pressure and central energy density of matter $\\sigma$, and the ratio of energy density of vacuum and central density of matter $\\lambda$. The static equilibrium configurations are determined by two coupled first-order nonlinear differential equations that are solved by numerical methods with the exception of polytropes with $n=0$ corresponding to the configurations with a uniform distribution of energy density, when the solution is given in terms of elementary functions. The geometry of the polytropes is conveniently represented by embedding diagrams of both the ordinary space geometry and the optical reference geometry reflecting some dynamical properties of the geodesic motion. The polytropes are represented by radial profiles of...

  18. Phantom energy mediates a long-range repulsive force.

    Science.gov (United States)

    Amendola, Luca

    2004-10-29

    Scalar field models with nonstandard kinetic terms have been proposed in the context of k inflation, of Born-Infeld Lagrangians, of phantom energy and, more in general, of low-energy string theory. In general, scalar fields are expected to couple to matter inducing a new interaction. In this Letter I derive the cosmological perturbation equations and the Yukawa correction to gravity for such general models. I find three interesting results: first, when the field behaves as phantom energy (equation of state less than -1), then the coupling strength is negative, inducing a long-range repulsive force; second, the dark-energy field might cluster on astrophysical scales; third, applying the formalism to a Brans-Dicke theory with a general kinetic term it is shown that its Newtonian effects depend on a single parameter that generalizes the Brans-Dicke constant.

  19. Soliton gyroscopes in media with spatially growing repulsive nonlinearity

    CERN Document Server

    Driben, Rodislav; Malomed, Boris A; Meier, Torsten; Torner, Lluis

    2013-01-01

    We find that the recently introduced model of self-trapping supported by a spatially growing strength of a repulsive nonlinearity gives rise to robust vortex-soliton tori, i.e., three-dimensional vortex solitons, with topological charges S. The family with S=1 is completely stable, while the one with S=2 has alternating regions of stability and instability. The families are nearly exactly reproduced in an analytical form by the Thomas-Fermi approximation (TFA). Unstable states with S=2 and 3 split into persistently rotating pairs or triangles of unitary vortices. Application of a moderate torque to the vortex torus initiates a persistent precession mode, with the torus' axle moving along a conical surface. A strong torque heavily deforms the vortex solitons, but, nonetheless, they restore themselves with the axle oriented according to the vectorial addition of angular momenta.

  20. 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.

  1. Thermodynamic curvature for attractive and repulsive intermolecular forces.

    Science.gov (United States)

    May, Helge-Otmar; Mausbach, Peter; Ruppeiner, George

    2013-09-01

    The thermodynamic curvature scalar R for the Lennard-Jones system is evaluated in phase space, including vapor, liquid, and solid state. We paid special attention to the investigation of R along vapor-liquid, liquid-solid, and vapor-solid equilibria. Because R is a measure of interaction strength, we traced out the line R=0 dividing the phase space into regions with effectively attractive (R0) interactions. Furthermore, we analyzed the dependence of R on the strength of attraction applying a perturbation ansatz proposed by Weeks-Chandler-Anderson. Our results show clearly a transition from R>0 (for poorly repulsive interaction) to R<0 when loading attraction in the intermolecular potential.

  2. 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.

    2016-01-01

    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 interactions facilitate packaging despite increasing the energy of the theoretical optimum spooled DNA conformation. PMID:24996111

  3. 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...

  4. 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.

  5. Roman vs. Arabic Computistics in Twelfth-Century England: A Newly Discovered Source (Collatio Compoti Romani et Arabici).

    Science.gov (United States)

    Nothaft, C Philipp E

    2015-01-01

    A frequently overlooked aspect of the knowledge transfer from Arabic into Latin in the twelfth century is the introduction of the Islamo-Arabic calendar, which confronted Western computists with a radically different scheme of lunar reckoning that was in some ways superior to the 19-year lunar cycle of the Roman Church. One of the earliest sources to properly discuss this new system and compare it to the old one is the anonymous Collatio Compoti Romani et Arabici, found in a manuscript from Tewkesbury Abbey, Gloucestershire. This article contains the first edition and translation of this previously unknown text, preceded by an analysis of its content and sources. As will be argued, the text was written in the second quarter of the twelfth century as a reaction to the astronomical tables of al-Khwāizmī, recently translated by Adelard of Bath, as well as to eclipse observations that had exposed the flaws of the 'Roman' computation.

  6. 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.

  7. Solid-solid transitions induced by repulsive interactions revisited

    Science.gov (United States)

    Navascués, G.; Velasco, E.; Mederos, L.

    2016-10-01

    We revisit a problem already studied 15 years ago by us in collaboration with Stell and Hemmer: the isostructural solid-solid transitions induced by repulsive particle interactions exhibited by classical systems interacting via the Stell-Hemmer potentials. The full phase diagram in the crystal region is obtained by applying a perturbation theory for classical solids used during our collaboration with Stell. Also, the performance of such a theory is now tested by comparing the perturbative phase diagram with that obtained from computer simulations. The latter was calculated using a recently refined method to obtain the free-energy of crystals by means of Monte Carlo simulations. The perturbation theory captures the correct topology and correctly identifies the stable, fcc and bcc, phases. In addition, the theory predicts the occurrence of special points: a point where the two stable structures coexist at the same density, and two critical points terminating the corresponding isostructural phase transitions for fcc and bcc phases. The location of some of these features in the phase diagram is predicted almost quantitatively. However, phase boundaries involving the non-compact bcc phase are much less accurate, a problem that can be traced to the poor representation used for the bcc phase of the reference, hard-sphere, system.

  8. Repulsive forces between looping chromosomes induce entropy-driven segregation.

    Directory of Open Access Journals (Sweden)

    Manfred Bohn

    Full Text Available One striking feature of chromatin organization is that chromosomes are compartmentalized into distinct territories during interphase, the degree of intermingling being much smaller than expected for linear chains. A growing body of evidence indicates that the formation of loops plays a dominant role in transcriptional regulation as well as the entropic organization of interphase chromosomes. Using a recently proposed model, we quantitatively determine the entropic forces between chromosomes. This Dynamic Loop Model assumes that loops form solely on the basis of diffusional motion without invoking other long-range interactions. We find that introducing loops into the structure of chromatin results in a multi-fold higher repulsion between chromosomes compared to linear chains. Strong effects are observed for the tendency of a non-random alignment; the overlap volume between chromosomes decays fast with increasing loop number. Our results suggest that the formation of chromatin loops imposes both compartmentalization as well as order on the system without requiring additional energy-consuming processes.

  9. Slit-Robo Repulsive Signaling Extrudes Tumorigenic Cells from Epithelia.

    Science.gov (United States)

    Vaughen, John; Igaki, Tatsushi

    2016-12-19

    Cells dynamically interact throughout animal development to coordinate growth and deter disease. For example, cell-cell competition weeds out aberrant cells to enforce homeostasis. In Drosophila, tumorigenic cells mutant for the cell polarity gene scribble (scrib) are actively eliminated from epithelia when surrounded by wild-type cells. While scrib cell elimination depends critically on JNK signaling, JNK-dependent cell death cannot sufficiently explain scrib cell extirpation. Thus, how JNK executed cell elimination remained elusive. Here, we show that repulsive Slit-Robo2-Ena signaling exerts an extrusive force downstream of JNK to eliminate scrib cells from epithelia by disrupting E-cadherin. While loss of Slit-Robo2-Ena in scrib cells potentiates scrib tumor formation within the epithelium, Robo2-Ena hyperactivation surprisingly triggers luminal scrib tumor growth following excess extrusion. This extrusive signaling is amplified by a positive feedback loop between Slit-Robo2-Ena and JNK. Our observations provide a potential causal mechanism for Slit-Robo dysregulation in numerous human cancers.

  10. Casimir-Polder repulsion near edges: wedge apex and a screen with an aperture

    CERN Document Server

    Milton, Kimball A; Parashar, Prachi; Pourtolami, Nima; Brevik, Iver; Ellingsen, Simen A

    2011-01-01

    Although repulsive effects have been predicted for quantum vacuum forces between bodies with nontrivial electromagnetic properties, such as between a perfect electric conductor and a perfect magnetic conductor, realistic repulsion seems difficult to achieve. Repulsion is possible if the medium between the bodies has a permittivity in value intermediate to those of the two bodies, but this may not be a useful configuration. Here, inspired by recent numerical work, we initiate analytic calculations of the Casimir-Polder interaction between an atom with anisotropic polarizability and a plate with an aperture. In particular, for a semi-infinite plate, and, more generally, for a wedge, the problem is exactly solvable, and for sufficiently large anisotropy, Casimir-Polder repulsion is indeed possible, in agreement with the previous numerical studies. In order to achieve repulsion, what is needed is a sufficiently sharp edge (not so very sharp, in fact) so that the directions of polarizability of the conductor and t...

  11. 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.

  12. Water anomalous thermodynamics, attraction, repulsion, and hydrophobic hydration

    Science.gov (United States)

    Cerdeiriña, Claudio A.; Debenedetti, Pablo G.

    2016-04-01

    A model composed of van der Waals-like and hydrogen bonding contributions that simulates the low-temperature anomalous thermodynamics of pure water while exhibiting a second, liquid-liquid critical point [P. H. Poole et al., Phys. Rev. Lett. 73, 1632 (1994)] is extended to dilute solutions of nonionic species. Critical lines emanating from such second critical point are calculated. While one infers that the smallness of the water molecule may be a relevant factor for those critical lines to move towards experimentally accessible regions, attention is mainly focused on the picture our model draws for the hydration thermodynamics of purely hydrophobic and amphiphilic non-electrolyte solutes. We first focus on differentiating solvation at constant volume from the corresponding isobaric process. Both processes provide the same viewpoint for the low solubility of hydrophobic solutes: it originates from the combination of weak solute-solvent attractive interactions and the specific excluded-volume effects associated with the small molecular size of water. However, a sharp distinction is found when exploring the temperature dependence of hydration phenomena since, in contrast to the situation for the constant-V process, the properties of pure water play a crucial role at isobaric conditions. Specifically, the solubility minimum as well as enthalpy and entropy convergence phenomena, exclusively ascribed to isobaric solvation, are closely related to water's density maximum. Furthermore, the behavior of the partial molecular volume and the partial molecular isobaric heat capacity highlights the interplay between water anomalies, attraction, and repulsion. The overall picture presented here is supported by experimental observations, simulations, and previous theoretical results.

  13. Power

    DEFF Research Database (Denmark)

    Elmholdt, Claus Westergård; Fogsgaard, Morten

    2016-01-01

    In this chapter, we will explore the dynamics of power in processes of creativity, and show its paradoxical nature as both a bridge and a barrier to creativity in organisations. Recent social psychological experimental research (Slighte, de Dreu & Nijstad, 2011) on the relation between power...... 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...... and floating source for empowering people in the organisation. We will explore and discuss here the potentials, challenges and pitfalls of power in relation to creativity in the life of organisations today. The aim is to demonstrate that power struggles may be utilised as constructive sources of creativity...

  14. General relativistic polytropes with a repulsive cosmological constant

    Science.gov (United States)

    Stuchlík, Zdeněk; Hledík, Stanislav; Novotný, Jan

    2016-11-01

    Spherically symmetric equilibrium configurations of perfect fluid obeying a polytropic equation of state are studied in spacetimes with a repulsive cosmological constant. The configurations are specified in terms of three parameters—the polytropic index n , the ratio of central pressure and central energy density of matter σ , and the ratio of energy density of vacuum and central density of matter λ . The static equilibrium configurations are determined by two coupled first-order nonlinear differential equations that are solved by numerical methods with the exception of polytropes with n =0 corresponding to the configurations with a uniform distribution of energy density, when the solution is given in terms of elementary functions. The geometry of the polytropes is conveniently represented by embedding diagrams of both the ordinary space geometry and the optical reference geometry reflecting some dynamical properties of the geodesic motion. The polytropes are represented by radial profiles of energy density, pressure, mass, and metric coefficients. For all tested values of n >0 , the static equilibrium configurations with fixed parameters n , σ , are allowed only up to a critical value of the cosmological parameter λc=λc(n ,σ ). In the case of n >3 , the critical value λc tends to zero for special values of σ . The gravitational potential energy and the binding energy of the polytropes are determined and studied by numerical methods. We discuss in detail the polytropes with an extension comparable to those of the dark matter halos related to galaxies, i.e., with extension ℓ>100 kpc and mass M >1 012 M⊙ . For such largely extended polytropes, the cosmological parameter relating the vacuum energy to the central density has to be larger than λ =ρvac/ρc˜10-9. We demonstrate that the extension of the static general relativistic polytropic configurations cannot exceed the so-called static radius related to their external spacetime, supporting the idea

  15. Long-range repulsive charged colloids in and out of equilibrium

    Science.gov (United States)

    van der Linden, M. N.

    2013-04-01

    The research described in this thesis focusses on the behaviour of charged colloidal particles with long-range repulsive interactions. The experimental model system we used consisted of sterically stabilised charged poly(methyl methacrylate) (PMMA) colloids suspended in cyclohexyl bromide (CHB). In this low-polar solvent very low ionic concentrations can be achieved, resulting in a large Debye screening length (on the order of the particle diameter), i.e. long-range interactions. The pair interaction in these systems is often modelled by the hard-core repulsive Yukawa (or screened Coulomb) potential, which we used for our computer simulations. In Monte Carlo simulations we investigated the effect of size polydispersity on the crystal-fluid transition. We observed a shift to higher volume fraction of the crystal-fluid transition upon increasing the polydispersity. At high polydispersities parts of the higher charged systems that were initially crystalline became amorphous. The amorphous parts had a higher polydispersity than the crystalline parts, indicating the presence of a terminal polydispersity beyond which the homogeneous crystal phase was no longer stable. We investigated the slow dynamics close to the glass transition as a function of the range of the potential, also in simulations. We determined the long-time structural relaxation time and long-time self-diffusion coefficient, which could be well fitted by a power law predicted by mode-coupling theory (MCT) and by the Vogel-Fulcher-Tammann (VFT) equation. In experiments we used confocal microscopy to study the system quantitatively in 3D on a single-particle level. We performed micro-electrophoresis measurements to determine the surface potential and charge of the PMMA particles at a volume fraction around 0.02. The surface potential was roughly independent of the diameter of the particle and was found to be lower for unlocked particles (steric stabiliser adsorbed to surface) than for locked particles

  16. Acceleration of particles to high energy via gravitational repulsion in the Schwarzschild field

    Science.gov (United States)

    McGruder, Charles H.

    2017-01-01

    Gravitational repulsion is an inherent aspect of the Schwarzschild solution of the Einstein-Hilbert field equations of general relativity. We show that this circumstance means that it is possible to gravitationally accelerate particles to the highest cosmic ray energies.

  17. Dilution and resonance enhanced repulsion in non-equilibrium fluctuation forces

    CERN Document Server

    Bimonte, Giuseppe; Kruger, Matthias; Kardar, Mehran

    2011-01-01

    In equilibrium, forces induced by fluctuations of the electromagnetic field between electrically polarizable objects (microscopic or macroscopic) in vacuum are always attractive. The force may, however, become repulsive for microscopic particles coupled to thermal baths with different temperatures. We demonstrate that this non-equilibrium repulsion can be realized also between macroscopic objects, as planar slabs, if they are kept at different temperatures. It is shown that repulsion can be enhanced by (i) tuning of material resonances in the thermal region, and by (ii) reducing the dielectric contrast due to "dilution". This can lead to stable equilibrium positions. We discuss the realization of these effects for aerogels, yielding repulsion down to sub-micron distances at realistic porosities.

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

    Energy Technology Data Exchange (ETDEWEB)

    Altsybeev, Igor [St. Petersburg State University (Russian Federation)

    2016-01-22

    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.

  19. Performance of repulsive type magnetic bearing system under nonuniform magnetization of permanent magnet

    OpenAIRE

    Ohji, T.; Mukhopadhyay, S. C.; Iwahara, Masayoshi; Yamada, Sotoshi

    2000-01-01

    Permanent magnet bearing system utilizes the repulsive forces between the stator and rotor permanent magnets (PM) for the levitation of the system and it results a simplified axial control scheme. A repulsive type magnetic bearing system based on the above principle was fabricated in our laboratory. Material characteristics and the configuration of the permanent magnets are the central component for this type of bearing system. Due to aging or as both the magnets are repelling each other, the...

  20. Repulsive and Restoring Casimir Forces Based on Magneto-Optical Effect

    Institute of Scientific and Technical Information of China (English)

    ZENG Ran; YANG Ya-Ping

    2011-01-01

    The Casimir force direction tuned by the external magnetic field due to the magneto-optical Voigt effect is investigated. The magneto-optical effect gives rise to the modified frequency-dependent electric permittivity and thus the electromagnetic properties of the materials can be adjusted to satisfy the condition of the formation of repulsive Casimir force. It is found that between the ordinary dielectric slab and magneto-optical material slab, a repulsive force may exist by adjusting the applied magnetic field. The restoring Casimir force can also be obtained if suitable parameter values are taken. For realistic materials, the repulsive and the restoring force is shown to possibly take place at typical distances in microelectromechanical systems.%@@ The Casimir force direction tuned by the external magnetic field due to the magneto-optical Voigt effect is investigated.The magneto-optical effect gives rise to the modified frequency-dependent electric permittivity and thus the electromagnetic properties of the materials can be adjusted to satisfy the condition of the formation of repulsive Casimir force.It is found that between the ordinary dielectric slab and magneto-optical material slab,a repulsive force may exist by adjusting the applied magnetic field.The restoring Casimir force can also be obtained if suitable parameter values are taken.For realistic materials,the repulsive and the restoring force is shown to possibly take place at typical distances in microelectromechanical systems.

  1. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan

    Science.gov (United States)

    de Foy, Benjamin; Lu, Zifeng; Streets, David G.

    2016-01-01

    China’s twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NOx) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO2 trends suggested that there was an increase in NO2 columns in most areas from 2005 to around 2011 which was followed by a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NOx emission inventories which were available up until 2014. This shows the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO2 columns. Satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan. PMID:27786278

  2. Satellite NO2 retrievals suggest China has exceeded its NOx reduction goals from the twelfth Five-Year Plan.

    Science.gov (United States)

    de Foy, Benjamin; Lu, Zifeng; Streets, David G

    2016-10-27

    China's twelfth Five-Year Plan included pollution control measures with a goal of reducing national emissions of nitrogen oxides (NOx) by 10% by 2015 compared with 2010. Multiple linear regression analysis was used on 11-year time series of all nitrogen dioxide (NO2) pixels from the Ozone Monitoring Instrument (OMI) over 18 NO2 hotspots in China. The regression analysis accounted for variations in meteorology, pixel resolution, seasonal effects, weekday variability and year-to-year variability. The NO2 trends suggested that there was an increase in NO2 columns in most areas from 2005 to around 2011 which was followed by a strong decrease continuing through 2015. The satellite results were in good agreement with the annual official NOx emission inventories which were available up until 2014. This shows the value of evaluating trends in emission inventories using satellite retrievals. It further shows that recent control strategies were effective in reducing emissions and that recent economic transformations in China may be having an effect on NO2 columns. Satellite information for 2015 suggests that emissions have continued to decrease since the latest inventories available and have surpassed the goals of the twelfth Five-Year Plan.

  3. Soft repulsive mixtures under gravity: Brazil-nut effect, depletion bubbles, boundary layering, nonequilibrium shaking

    Science.gov (United States)

    Kruppa, Tobias; Neuhaus, Tim; Messina, René; Löwen, Hartmut

    2012-04-01

    A binary mixture of particles interacting via long-ranged repulsive forces is studied in gravity by computer simulation and theory. The more repulsive A-particles create a depletion zone of less repulsive B-particles around them reminiscent to a bubble. Applying Archimedes' principle effectively to this bubble, an A-particle can be lifted in a fluid background of B-particles. This "depletion bubble" mechanism explains and predicts a brazil-nut effect where the heavier A-particles float on top of the lighter B-particles. It also implies an effective attraction of an A-particle towards a hard container bottom wall which leads to boundary layering of A-particles. Additionally, we have studied a periodic inversion of gravity causing perpetuous mutual penetration of the mixture in a slit geometry. In this nonequilibrium case of time-dependent gravity, the boundary layering persists. Our results are based on computer simulations and density functional theory of a two-dimensional binary mixture of colloidal repulsive dipoles. The predicted effects also occur for other long-ranged repulsive interactions and in three spatial dimensions. They are therefore verifiable in settling experiments on dipolar or charged colloidal mixtures as well as in charged granulates and dusty plasmas.

  4. A requirement for filopodia extension toward Slit during Robo-mediated axon repulsion.

    Science.gov (United States)

    McConnell, Russell E; Edward van Veen, J; Vidaki, Marina; Kwiatkowski, Adam V; Meyer, Aaron S; Gertler, Frank B

    2016-04-25

    Axons navigate long distances through complex 3D environments to interconnect the nervous system during development. Although the precise spatiotemporal effects of most axon guidance cues remain poorly characterized, a prevailing model posits that attractive guidance cues stimulate actin polymerization in neuronal growth cones whereas repulsive cues induce actin disassembly. Contrary to this model, we find that the repulsive guidance cue Slit stimulates the formation and elongation of actin-based filopodia from mouse dorsal root ganglion growth cones. Surprisingly, filopodia form and elongate toward sources of Slit, a response that we find is required for subsequent axonal repulsion away from Slit. Mechanistically, Slit evokes changes in filopodium dynamics by increasing direct binding of its receptor, Robo, to members of the actin-regulatory Ena/VASP family. Perturbing filopodium dynamics pharmacologically or genetically disrupts Slit-mediated repulsion and produces severe axon guidance defects in vivo. Thus, Slit locally stimulates directional filopodial extension, a process that is required for subsequent axonal repulsion downstream of the Robo receptor.

  5. Repulsive magnetic levitation-based ocean wave energy harvester with variable resonance: Modeling, simulation and experiment

    Science.gov (United States)

    Masoumi, Masoud; Wang, Ya

    2016-10-01

    This paper investigates a magnetic levitation characteristic used in a vibration based energy harvester, called repulsive magnetic scavenger (RMS). The RMS is capable of harvesting ocean wave energy with a unique repelling permanent magnet array, which provides a stronger and more uniform magnetic field, compared to its attracting magnetic counterparts. The levitating magnets are stacked together around a threaded rod so that the same pole is facing each other. Two fixed magnets placed with one at each end of the RMS provides a collocated harvesting and braking mechanism in the face of high amplitude vibrations. Magnets in the levitated magnet stack are separated by pole pieces which are made of metals to intensify the magnetic field strength. The effect of the thickness and the use of different materials with different permeability for pole pieces is also studied to obtain an optimal energy harvesting efficiency. Moreover, the procedure to find the restoring force applied to the levitating magnet stack is demonstrated. Then, the Duffing vibration equation of the harvester is solved and the frequency response function is calculated for various force amplitudes and electrical damping so as to investigate the effect of these parameters on the response of the system. Furthermore, the effect of the maximum displacement of the moving magnet stack on the natural frequency of the device is studied. And finally, Faraday's law is employed to estimate the output voltage and power of the system under the specified input excitation force. Experiments show that the output emf voltage of the manufactured prototype reaches up to 42 V for an excitation force with the frequency of 9 Hz and the maximum amplitude of 3.4 g.

  6. Isomorphs in the phase diagram of a model liquid without inverse power law repulsion

    DEFF Research Database (Denmark)

    Veldhorst, Arnold Adriaan; Bøhling, Lasse; Dyre, J. C.;

    2012-01-01

    It is demonstrated by molecular dynamics simulations that liquids interacting via the Buckingham potential are strongly correlating, i.e., have regions of their phase diagram where constant-volume equilibrium fluctuations in the virial and potential energy are strongly correlated. A binary...... Buckingham liquid is cooled to a viscous phase and shown to have isomorphs, which are curves in the phase diagram along which structure and dynamics in appropriate units are invariant to a good approximation. To test this, the radial distribution function, and both the incoherent and coherent intermediate...

  7. Academic Adjustment of Gifted and Non-Gifted Ninth-, Tenth-, Eleventh-, and Twelfth-Grade Students Placed in Accelerated Mathematics Courses

    Science.gov (United States)

    Speer, Emily M.

    2013-01-01

    This study investigated the academic adjustment of gifted and non-gifted ninth-, tenth-, eleventh-, and twelfth-grade students placed in accelerated mathematics courses. Using Van Eman's research, the investigation of the social and emotional effects of mathematics acceleration through academic adjustment included the following positive indicators…

  8. Evidence for ferromagnetic instability in a repulsive Fermi gas of ultracold atoms

    CERN Document Server

    Valtolina, G; Amico, A; Burchianti, A; Recati, A; Enss, T; Inguscio, M; Zaccanti, M; Roati, G

    2016-01-01

    Ferromagnetism is among the most spectacular manifestations of interactions within many-body fermion systems. In contrast to weak-coupling phenomena, it requires strong repulsion to develop, making a quantitative description of ferromagnetic materials notoriously difficult. This is especially true for itinerant ferromagnets, where magnetic moments are not localized into a crystal lattice. In particular, it is still debated whether the simplest case envisioned by Stoner of a homogeneous Fermi gas with short-range repulsive interactions can exhibit ferromagnetism at all. In this work, we positively answer this question by studying a clean model system consisting of a binary spin-mixture of ultracold 6Li atoms, whose repulsive interaction is tuned via a Feshbach resonance. We drastically limit detrimental pairing effects that affected previous studies by preparing the gas in a magnetic domain-wall configuration. We reveal the ferromagnetic instability by observing the softening of the spin-dipole collective mode...

  9. Repulsion of polarised particles from anisotropic materials with a near-zero permittivity component

    Institute of Scientific and Technical Information of China (English)

    Francisco J Rodríguez-Fortu(n)o; Anatoly V Zayats

    2016-01-01

    Reduction of adhesion and stiction is crucial for robust operation on nanomechanical and optofluidic devices as well as atom and molecule behaviour near surfaces.It can be achieved using electric charging,magnetic materials or light pressure and optical trapping.Here we show that a particle scattering or emitting in close proximity to an anisotropic substrate can experience a repulsive force if one of the diagonal components of the permittivity tensor is close to zero.We derive an analytic condition for the existence of such repulsive force depending on the optical properties of the substrate.We also demonstrate the effect using realistic anisotropic metamaterial implementations of a substrate.The anisotropic metamaterial approach using metal-dielectric and graphene-dielectric multilayers provides a tuneable spectral range and a very broad bandwidth of electromagnetic repulsion forces,in contrast to isotropic substrates.

  10. Unc5B associates with LARG to mediate the action of repulsive guidance molecule.

    Science.gov (United States)

    Hata, Katsuhiko; Kaibuchi, Kozo; Inagaki, Shinobu; Yamashita, Toshihide

    2009-03-09

    Neuronal axons are guided by attractive and repulsive cues in their local environment. Because the repulsive guidance molecule A (RGMa) was originally identified as an axon repellent in the visual system, diverse functions in the developing and adult central nervous system have been ascribed to it. RGMa binding to its receptor neogenin induces RhoA activation, leading to inhibitory/repulsive behavior and collapse of the neuronal growth cone. However, the precise mechanisms that regulate RhoA activation are poorly understood. In this study, we show that Unc5B, a member of the netrin receptor family, interacts with neogenin as a coreceptor for RGMa. Moreover, leukemia-associated guanine nucleotide exchange factor (LARG) associates with Unc5B to transduce the RhoA signal. Focal adhesion kinase (FAK) is involved in RGMa-induced tyrosine phosphorylation of LARG as well as RhoA activation. These findings uncover the molecular basis for diverse functions mediated by RGMa.

  11. Density dependence of the /s-wave repulsion in pionic atoms

    Science.gov (United States)

    Friedman, E.

    2002-11-01

    Several mechanisms of density dependence of the s-wave repulsion in pionic atoms, beyond the conventional model, are tested by parameter fits to a large (106 points) set of data from 16O to 238U, including 'deeply bound' states in 205Pb. Special attention is paid to the proper choice of nuclear density distributions. A density-dependent isovector scattering amplitude suggested recently by Weise to result from a density dependence of the pion decay constant is introduced and found to account for most of the so-called anomalous repulsion. The presence of such an effect might indicate partial chiral symmetry restoration in dense matter. The anomalous repulsion is fully accounted for when an additional relativistic impulse approximation term is included in the potential.

  12. A new conveyor system based on a passive magnetic levitation unit having repulsive-type magnetic bearings

    Science.gov (United States)

    Ohji, T.; Ichiyama, S.; Amei, K.; Sakui, M.; Yamada, S.

    2004-05-01

    A magnetic repulsive-type conveyor system is proposed as a new application of repulsive-type magnetic bearings, which use repulsive forces between the stator and rotor permanent magnets. The proposed conveyer is composed by aligning many passive magnetic levitation units. Each unit also contains electromagnets to oscillate a levitator shaft in the radial direction. The way of generating vibration and rotation in the conveyance direction was examined by the various excitation methods.

  13. 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.

  14. 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 repu

  15. Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate

    DEFF Research Database (Denmark)

    Jørgensen, Nils B.; Wacker, Lars; Skalmstang, Kristoffer Theis;

    2016-01-01

    for an impurity interacting with a Bose-Einstein condensate (BEC). We measure the energy of the impurity both for attractive and repulsive interactions with the BEC, and find excellent agreement with theories that incorporate three-body correlations, both in the weak-coupling limits and across unitarity. Our...

  16. Motion noise changes directional interaction between transparently moving stimuli from repulsion to attraction.

    Directory of Open Access Journals (Sweden)

    Jennifer L Gaudio

    Full Text Available To interpret visual scenes, visual systems need to segment or integrate multiple moving features into distinct objects or surfaces. Previous studies have found that the perceived direction separation between two transparently moving random-dot stimuli is wider than the actual direction separation. This perceptual "direction repulsion" is useful for segmenting overlapping motion vectors. Here we investigate the effects of motion noise on the directional interaction between overlapping moving stimuli. Human subjects viewed two overlapping random-dot patches moving in different directions and judged the direction separation between the two motion vectors. We found that the perceived direction separation progressively changed from wide to narrow as the level of motion noise in the stimuli was increased, showing a switch from direction repulsion to attraction (i.e. smaller than the veridical direction separation. We also found that direction attraction occurred at a wider range of direction separations than direction repulsion. The normalized effects of both direction repulsion and attraction were the strongest near the direction separation of ∼25° and declined as the direction separation further increased. These results support the idea that motion noise prompts motion integration to overcome stimulus ambiguity. Our findings provide new constraints on neural models of motion transparency and segmentation.

  17. Polymer Brushes that Mimic Repulsive Properties of the Boundary Lubricant Glycoprotein Lubricin

    Science.gov (United States)

    Torres, Jahn; Jay, Gregory; Ni, Qian; Bello, David; Bothun, Geoffrey; Kim, Kyung-Suk

    2011-03-01

    This is a report on the design of tailored functional groups which mimic the repulsive forces at work in the natural-joint boundary lubricant known as lubricin. Lubricin, an amphiphilic polyelectrolyte biomolecule, decreases friction and cellular adhesion by exhibiting surface force fields based on steric hindrance, Debye electrostatic double layer repulsion and hydration repulsive forces. We have identified a physically and chemically stable candidate polymers for anti-fouling coatings that will mimic lubricin's repulsive properties. Synthetic polymer brushes mimicking lubricin have been produced using these polymers grafted onto a glass surfaces. The average adhesive forces for the polymer brushes measured through atomic force microscopy are as low (56.796 +/- 0.796 mN/m), similar to those exhibited by lubricin coated surfaces and on the same order of magnitude as superhydrophobic surfaces. This work was supported by the Coatings/Biofouling Program and the Maritime Sensing Program of the Office of Naval Research as well as the ILIR Program of the Naval Undersea Warfare Center DIVNPT.

  18. Improvement of the repulsive part of the classical interatomic potential for SiC

    CERN Document Server

    Belko, V; Chagarov, E

    2003-01-01

    In order to enable a better description of ballistic and athermal processes occurring in the initial stage of ion-beam-induced defect formation, the repulsive part of the interatomic potentials of Gao and Tersoff is improved. The first modification concerns the two-body part of the potentials. At small interatomic distances it is replaced by the well-tested potential of Ziegler, Biersack and Littmark (ZBL). For repulsive interactions between zero and some 10 electron volt, an exponential spline function is employed to connect the ZBL potential with the two-body part of the Tersoff and the Gao potential. The modified two-body potentials and their first derivatives are continuous and monotonic over the whole range of repulsive interaction. They are in good agreement with data obtained by density-functional-theory calculations. Furthermore, the three-body part of the Tersoff and the Gao potential is modified in order to avoid the strong dependence of repulsive interactions between two atoms on the bond-order par...

  19. Boundary Effects for One-Dimensional Bariev Model with Hard-Core Repulsion

    Institute of Scientific and Technical Information of China (English)

    LIXiao-Jun; YUERui-Hong

    2004-01-01

    For the Bariev model for correlated hopping in one dimension under open boundary conditions, the Bethe ansatz equations are analyzed for both a repulsive and an attractive interaction in several limiting cases, i.e., the ground state, the weak and strong coupling limits. The contributions of the boundary fields to both the magnetic susceptibility and the specific heat are obtained.

  20. Boundary Effects for One-Dimensional Bariev Model with Hard-Core Repulsion

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Jun; YUE Rui-Hong

    2004-01-01

    For the Bariey model for correlated hopping in one dimension under open boundary conditions, the Bethe ansatz equations are analyzed for both a repulsive and an attractive interaction in several limiting cases, i.e., the ground state, the weak and strong coupling limits. The contributions of the boundary fields to both the magnetic susceptibility and the specific heat are obtained.

  1. Disentangling interatomic repulsion and anharmonicity in the viscosity and fragility of glasses

    Science.gov (United States)

    Krausser, J.; Lagogianni, A. E.; Samwer, K.; Zaccone, A.

    2017-03-01

    Within the shoving model of the glass transition, the relaxation time and the viscosity are related to the local cage rigidity. This approach can be extended down to the atomic level in terms of the interatomic interaction or potential of mean force. We applied this approach to both real metallic glass formers and model Lennard-Jones glasses. The main outcome of this analysis is that in metallic glasses the thermal expansion contribution is mostly independent of composition and is uncorrelated with the interatomic repulsion: As a consequence, the fragility increases upon increasing the interatomic repulsion steepness. In the Lennard-Jones glasses, the scenario is opposite: Thermal expansion and interatomic repulsion contributions are strongly correlated, and the fragility decreases upon increasing the repulsion steepness. This framework allows one to tell apart systems where "soft atoms make strong glasses" from those where, instead, "soft atoms make fragile glasses." Hence, it opens up the way for the rational, atomistic tuning of the fragility and viscosity of widely different glass-forming materials all the way from strong to fragile.

  2. 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.

  3. The s-wave repulsion and deeply bound pionic atoms: fact and fancy

    Science.gov (United States)

    Friedman, E.; Gal, A.

    2003-06-01

    Fits to a large data set of pionic atoms show that the 'missing' s-wave repulsion is accounted for when a density dependence suggested recently by Weise is included in the isovector term of the s-wave pion optical potential. The importance of using large data sets is demonstrated and the role of deeply bound pionic atom states is discussed.

  4. Shh signaling guides spatial pathfinding of raphespinal tract axons by multidirectional repulsion

    Institute of Scientific and Technical Information of China (English)

    Lijuan Song; Yuehui Liu; YangYu; Xin Duan; Shening Qi; Yaobo Liu

    2012-01-01

    Relatively little is known about the molecular mechanisms underlying spatial pathfinding in the descending serotonergic raphespinal tract (RST) in the developing spinal cord,one of the most important nerve pathways for pain,sensory and motor functions.We provide evidence that ventral floor plate-secreted Sonic hedgehog (Shh) is responsible for the establishment of decreasing gradients in both the anterior-to-posterior (A-P) and the medialto-lateral (M-L) directions in the ventral spinal cord during serotonergic RST axon projection.Downstream components of the Shh pathway,Patched 1 (Ptch1) and Smoothened (Smo),were expressed in the serotonergic caudal raphe nuclei and enriched in the descending serotonergic RST axons.Diffusible Shh repulsion of serotonergic RST axons was shown to be mediated by Shh-Ptch1 interactions and derepression of Smo.Using a co-culture assay,we showed that A-P graded repulsion mediated by Shh signaling pushed the serotonergic axons caudally through the ventral spinal cord and M-L graded repulsion mediated by Shh signaling simultaneously restricted the serotonergic axons to the ventral and ventral-lateral funiculus.Prominent pathfinding errors of serotonergic RST axons were observed in various Shh,Ptch1 and Smo mutants.We conclude that Shh signaling-mediated multidirectional repulsion is required to push descending serotonergic RST axons in the A-P direction,and to restrict these axons to the ventral and ventral-lateral funiculus in the M-L direction.This is the first demonstration that Shh signalingmediated muitidirectional repulsion of serotonergic RST axons maintains spatial axon pathfinding in the developing spinal cord.

  5. Shh signaling guides spatial pathfinding of raphespinal tract axons by multidirectional repulsion.

    Science.gov (United States)

    Song, Lijuan; Liu, Yuehui; Yu, Yang; Duan, Xin; Qi, Shening; Liu, Yaobo

    2012-04-01

    Relatively little is known about the molecular mechanisms underlying spatial pathfinding in the descending serotonergic raphespinal tract (RST) in the developing spinal cord, one of the most important nerve pathways for pain, sensory and motor functions. We provide evidence that ventral floor plate-secreted Sonic hedgehog (Shh) is responsible for the establishment of decreasing gradients in both the anterior-to-posterior (A-P) and the medial-to-lateral (M-L) directions in the ventral spinal cord during serotonergic RST axon projection. Downstream components of the Shh pathway, Patched 1 (Ptch1) and Smoothened (Smo), were expressed in the serotonergic caudal raphe nuclei and enriched in the descending serotonergic RST axons. Diffusible Shh repulsion of serotonergic RST axons was shown to be mediated by Shh-Ptch1 interactions and derepression of Smo. Using a co-culture assay, we showed that A-P graded repulsion mediated by Shh signaling pushed the serotonergic axons caudally through the ventral spinal cord and M-L graded repulsion mediated by Shh signaling simultaneously restricted the serotonergic axons to the ventral and ventral-lateral funiculus. Prominent pathfinding errors of serotonergic RST axons were observed in various Shh, Ptch1 and Smo mutants. We conclude that Shh signaling-mediated multidirectional repulsion is required to push descending serotonergic RST axons in the A-P direction, and to restrict these axons to the ventral and ventral-lateral funiculus in the M-L direction. This is the first demonstration that Shh signaling-mediated multidirectional repulsion of serotonergic RST axons maintains spatial axon pathfinding in the developing spinal cord.

  6. Interaction of hydrocarbon monolayer surfaces across n-alkanes: A steric repulsion

    Science.gov (United States)

    Herder, Christina E.; Ninham, Barry W.; Christenson, Hugo K.

    1989-05-01

    We present results of force measurements between hydrocarbon monolayer surfaces across n-alkanes (hexane, decane, and tetradecane). The interaction is qualitatively different from that of any previously studied system and, in particular, bears no resemblance to an oscillatory solvation force. Instead, the force is repulsive from about 2.5 nm, with the exception of a shallow minimum just outside a force maximum at 0.8-0.9 nm. At smaller separations the force becomes attractive and there is a weak adhesion at contact. We suggest that the force law is due to a steric effect—a repulsive interaction originating in restrictions on chain conformations of the alkanes at small surface separations. This interaction is accessible via simple mean-field theories. The similarity of the liquid-liquid and liquid-surface interactions allows this to dominate over solvation effects. The results are of significance for interaggregate interactions in lamellar liquid crystals, microemulsions, and surfactant-stabilized dispersions.

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

    CERN Document Server

    Reyes, Luz Marina; Aguilar, José Edgar Madriz; Bellini, Mauricio

    2012-01-01

    We investigate, in the transverse traceless (TT) gauge, the generation of the relic background of gravitational waves, generated during an 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, which 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 is possible to derive 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.

  8. Thermodynamic equivalence of two-dimensional imperfect attractive Fermi and repulsive Bose gases

    Science.gov (United States)

    Napiórkowski, Marek; Piasecki, Jarosław

    2017-06-01

    We consider two-dimensional imperfect attractive Fermi and repulsive Bose gases consisting of spinless point particles whose total interparticle interaction energy is represented by a N2/2 V with a =-aF≤0 for fermions and a =aB≥0 for bosons. We show that, in spite of the attraction, the thermodynamics of a d =2 imperfect Fermi gas remains well defined for 0 ≤aF≤a0=h2/2 π m , and is exactly the same as the one of the repulsive imperfect Bose gas with aB=a0-aF . In particular, for aF=a0 one observes the thermodynamic equivalence of the attractive imperfect Fermi gas and the ideal Bose gas.

  9. Acute behavioral responses to pheromones in C. elegans (adult behaviors: attraction, repulsion).

    Science.gov (United States)

    Jang, Heeun; Bargmann, Cornelia I

    2013-01-01

    The pheromone drop test is a simple and robust behavioral assay to quantify acute avoidance of pheromones in C. elegans, and the suppression of avoidance by attractive pheromones. In the pheromone drop test, water-soluble C. elegans pheromones are individually applied to animals that are freely moving on a large plate. Upon encountering a repellent, each C. elegans animal may or may not try to escape by making a long reversal. The fraction of animals that make a long reversal response indicates the repulsiveness of a given pheromone to a specific genotype/strain of C. elegans. Performing the drop test in the presence of bacterial food enhances the avoidance response to pheromones. Attraction to pheromones can be assayed by the suppression of reversals to repulsive pheromones or by the suppression of the basal reversal rate to buffer.

  10. Fast calculation of two-electron-repulsion integrals: a numerical approach

    CERN Document Server

    Lopes, Pedro E M

    2016-01-01

    An alternative methodology to evaluate two-electron-repulsion integrals based on numerical approximation is proposed. Computational chemistry has branched into two major fields with methodologies based on quantum mechanics and classical force fields. However, there are significant shadowy areas not covered by any of the available methods. Many relevant systems are often too big for traditional quantum chemical methods while being chemically too complex for classical force fields. Examples include systems in nanomedicine, studies of metalloproteins, etc. There is an urgent need to develop fast quantum chemical methods able to study large and complex systems. This work is a proof-of-concept on the numerical techniques required to develop accurate and computationally efficient algorithms for the fast calculation of electron-repulsion integrals, one of the most significant bottlenecks in the extension of quantum chemistry to large systems. All concepts and calculations were developed for the three-center integral...

  11. Synchronization and beam forming in an array of repulsively coupled oscillators.

    Science.gov (United States)

    Rulkov, N F; Tsimring, L; Larsen, M L; Gabbay, M

    2006-11-01

    We study the dynamics of an array of Stuart-Landau oscillators with repulsive coupling. Autonomous network with global repulsive coupling settles on one from a continuum of synchronized regimes characterized by zero mean field. Driving this array by an external oscillatory signal produces a nonzero mean field that follows the driving signal even when the oscillators are not locked to the external signal. At sufficiently large amplitude the external signal synchronizes the oscillators and locks the phases of the array oscillations. Application of this system as a beam-forming element of a phase array antenna is considered. The phase dynamics of the oscillator array synchronization is used to reshape the phases of signals received from the phase array antenna and improve its beam pattern characteristics.

  12. Classical and Quantum Analysis of Repulsive Singularities in Four Dimensional Extended Supergravity

    CERN Document Server

    Gaida, I; Stewart, J M

    1999-01-01

    Non--minimal repulsive singularities (``repulsons'') in extended supergravity theories are investigated. The short distance antigravity properties of the repulsons are tested at the classical and the quantum level by a scalar test--particle. Using a partial wave expansion it is shown that the particle gets totally reflected at the origin. A high frequency incoming particle undergoes a phase shift of $\\frac{\\pi}{2}$. However, the phase shift for a low--frequency particle depends upon the physical data of the repulson. The curvature singularity at a finite distance $r_h$ turns out to be transparent for the scalar test--particle and the coordinate singularity at the origin serves as a repulsive barrier at which particles bounce off.

  13. 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

  14. 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

    Ultracold Fermi gases with tunable interactions provide a test bed for exploring the many-body physics of strongly interacting quantum systems1, 2, 3, 4. Over the past decade, experiments have investigated many intriguing phenomena, and precise measurements of ground-state properties have provided...... benchmarks for the development of theoretical descriptions. Metastable states in Fermi gases with strong repulsive interactions5, 6, 7, 8, 9, 10, 11 represent an exciting area of development. The realization of such systems is challenging, because a strong repulsive interaction in an atomic quantum gas...... implies the existence of a weakly bound molecular state, which makes the system intrinsically unstable against decay. Here we use radio-frequency spectroscopy to measure the complete excitation spectrum of fermionic 40K impurities resonantly interacting with a Fermi sea of 6Li atoms. In particular, we...

  15. Research on ultra-fast vacuum mechanical switch driven by repulsive force actuator

    Science.gov (United States)

    Yuan, Zhao; He, Junjia; Pan, Yuan; Jing, Xin; Zhong, Canyi; Zhang, Ning; Wei, Xiaoguang; Tang, Guangfu

    2016-12-01

    In order to meet the fast operation demands of DC circuit breakers, a high-speed vacuum mechanical switch (VMS) driven by a repulsive force actuator is focused. To improve the drive speed and energy conversion efficiency (ECE) of the actuators, the dynamic characteristics of the double sided coil repulsive force actuators are investigated, and two generalized optimization design methods focusing on the aspect ratio of the driving coils (defined as ARF) and the electrical parameters (defined as EF) are developed. FEM simulation models' simulation and tests of VMS prototypes are conducted to verify the optimization methods. Results prove that the ARF method could improve the ECE of a VMS from 1.05% to 7.55%, and EF method could improve ECE of the same VMS from 1.05% to 6.61%, the combination of ARF and EF could improve the value of VMS's ECE to 10.50%, thus proving the validity and accuracy of the optimization methods.

  16. Controlling the growth of multiple ordered heteromolecular phases by utilizing intermolecular repulsion

    Science.gov (United States)

    Henneke, Caroline; Felter, Janina; Schwarz, Daniel; Stefan Tautz, F.; Kumpf, Christian

    2017-06-01

    Metal/organic interfaces and their structural, electronic, spintronic and thermodynamic properties have been investigated intensively, aiming to improve and develop future electronic devices. In this context, heteromolecular phases add new design opportunities simply by combining different molecules. However, controlling the desired phases in such complex systems is a challenging task. Here, we report an effective way of steering the growth of a bimolecular system composed of adsorbate species with opposite intermolecular interactions--repulsive and attractive, respectively. The repulsive species forms a two-dimensional lattice gas, the density of which controls which crystalline phases are stable. Critical gas phase densities determine the constant-area phase diagram that describes our experimental observations, including eutectic regions with three coexisting phases. We anticipate the general validity of this type of phase diagram for binary systems containing two-dimensional gas phases, and also show that the density of the gas phase allows engineering of the interface structure.

  17. Hydration Repulsion between Carbohydrate Surfaces Mediated by Temperature and Specific Ions

    Science.gov (United States)

    Chen, Hsieh; Cox, Jason R.; Ow, Hooisweng; Shi, Rena; Panagiotopoulos, Athanassios Z.

    2016-06-01

    Stabilizing colloids or nanoparticles in solution involves a fine balance between surface charges, steric repulsion of coating molecules, and hydration forces against van der Waals attractions. At high temperature and electrolyte concentrations, the colloidal stability of suspensions usually decreases rapidly. Here, we report a new experimental and simulation discovery that the polysaccharide (dextran) coated nanoparticles show ion-specific colloidal stability at high temperature, where we observed enhanced colloidal stability of nanoparticles in CaCl2 solution but rapid nanoparticle-nanoparticle aggregation in MgCl2 solution. The microscopic mechanism was unveiled in atomistic simulations. The presence of surface bound Ca2+ ions increases the carbohydrate hydration and induces strongly polarized repulsive water structures beyond at least three hydration shells which is farther-reaching than previously assumed. We believe leveraging the binding of strongly hydrated ions to macromolecular surfaces represents a new paradigm in achieving absolute hydration and colloidal stability for a variety of materials, particularly under extreme conditions.

  18. Observation of repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms

    CERN Document Server

    Scazza, F; Massignan, P; Recati, A; Amico, A; Burchianti, A; Fort, C; Inguscio, M; Zaccanti, M; Roati, G

    2016-01-01

    We employ radio-frequency spectroscopy to investigate a polarized spin-mixture of ultracold ${}^6$Li atoms close to a broad Feshbach scattering resonance. Focusing on the regime of strong repulsive interactions, we observe well-defined coherent quasiparticles even for unitarity-limited interactions. We characterize the many-body system by extracting the key properties of repulsive Fermi polarons: the energy $E_+$, the effective mass $m^*$, the residue $Z$ and the decay rate $\\Gamma$. Above a critical interaction, $E_+$ is found to exceed the Fermi energy of the bath while $m^*$ diverges and even turns negative. Such findings reveal that the paramagnetic Fermi liquid state becomes thermodynamically unstable towards an energetically favored ferromagnetic phase.

  19. Tan's contact and the phase distribution of repulsive Fermi gases: Insights from QCD noise analyses

    CERN Document Server

    Porter, William J

    2016-01-01

    Path-integral analyses originally pioneered in the study of the complex-phase problem afflicting lattice calculations of finite-density quantum chromodynamics are generalized to non-relativistic Fermi gases with repulsive interactions. Using arguments similar to those previously applied to relativistic theories, we show that the analogous problem in nonrelativistic systems manifests itself naturally in Tan's contact as a nontrivial cancellation between terms with varied dependence on extensive thermodynamic quantities. We analyze that case under the assumption of gaussian phase distribution, which is supported by our Monte Carlo calculations and perturbative considerations. We further generalize these results to observables other than the contact, as well as to polarized systems and systems with fixed particle number. Our results are quite general in that they apply to repulsive multi-component fermions, are independent of dimensionality or trapping potential, and hold in the ground state as well as at finite...

  20. Equine maxilar molar exodontia by repulsion: description of two different surgical techniques

    OpenAIRE

    Montero, Javier; Estrada, Juan; Estrada, Ricardo; Vargas, Jose; Somarriba, Miguel; Harrington, Stephanie; Segura, Carlos; Estrada, Manuel

    2013-01-01

    Two modifications of the technique for molar exodontia by repulsion are described. Each clinical case had the first maxilar molar on the left side (tooth number 209) extracted using one of the two modifications. Each surgical procedure was performed by a different veterinary surgeon. Both procedures, although similar, differed in equipment used, surgical approach and postoperative care. The surgical procedure in both patients was performed with the horse in the standing position under the eff...

  1. 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 $...... that cold atoms may be used to study quantum chaos both in the presence and absence of interactions....

  2. Equine maxilar molar exodontia by repulsion: description of two different surgical techniques

    OpenAIRE

    Montero, Javier; Estrada, Juan; Estrada, Ricardo; Vargas, Jose; Somarriba, Miguel; Harrington, Stephanie; Segura, Carlos; Estrada, Manuel

    2013-01-01

    Two modifications of the technique for molar exodontia by repulsion are described. Each clinical case had the first maxilar molar on the left side (tooth number 209) extracted using one of the two modifications. Each surgical procedure was performed by a different veterinary surgeon. Both procedures, although similar, differed in equipment used, surgical approach and postoperative care. The surgical procedure in both patients was performed with the horse in the standing position under the eff...

  3. 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.

  4. Stabilization of thin liquid films by repulsive van der Waals force.

    Science.gov (United States)

    Li, Er Qiang; Vakarelski, Ivan U; Chan, Derek Y C; Thoroddsen, Sigurdur T

    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.

  5. From hydration repulsion to dry adhesion between asymmetric hydrophilic and hydrophobic surfaces.

    Science.gov (United States)

    Kanduč, Matej; Netz, Roland R

    2015-10-01

    Using all-atom molecular dynamics (MD) simulations at constant water chemical potential in combination with basic theoretical arguments, we study hydration-induced interactions between two overall charge-neutral yet polar planar surfaces with different wetting properties. Whether the water film between the two surfaces becomes unstable below a threshold separation and cavitation gives rise to long-range attraction, depends on the sum of the two individual surface contact angles. Consequently, cavitation-induced attraction also occurs for a mildly hydrophilic surface interacting with a very hydrophobic surface. If both surfaces are very hydrophilic, hydration repulsion dominates at small separations and direct attractive force contribution can-if strong enough-give rise to wet adhesion in this case. In between the regimes of cavitation-induced attraction and hydration repulsion we find a narrow range of contact angle combinations where the surfaces adhere at contact in the absence of cavitation. This dry adhesion regime is driven by direct surface-surface interactions. We derive simple laws for the cavitation transition as well as for the transition between hydration repulsion and dry adhesion, which favorably compare with simulation results in a generic adhesion state diagram as a function of the two surface contact angles.

  6. Large attractive depletion interactions in soft repulsive-sphere binary mixtures.

    Science.gov (United States)

    Cinacchi, Giorgio; Martínez-Ratón, Yuri; Mederos, Luis; Navascués, Guillermo; Tani, Alessandro; Velasco, Enrique

    2007-12-07

    We consider binary mixtures of soft repulsive spherical particles and calculate the depletion interaction between two big spheres mediated by the fluid of small spheres, using different theoretical and simulation methods. The validity of the theoretical approach, a virial expansion in terms of the density of the small spheres, is checked against simulation results. Attention is given to the approach toward the hard-sphere limit and to the effect of density and temperature on the strength of the depletion potential. Our results indicate, surprisingly, that even a modest degree of softness in the pair potential governing the direct interactions between the particles may lead to a significantly more attractive total effective potential for the big spheres than in the hard-sphere case. This might lead to significant differences in phase behavior, structure, and dynamics of a binary mixture of soft repulsive spheres. In particular, a perturbative scheme is applied to predict the phase diagram of an effective system of big spheres interacting via depletion forces for a size ratio of small and big spheres of 0.2; this diagram includes the usual fluid-solid transition but, in the soft-sphere case, the metastable fluid-fluid transition, which is probably absent in hard-sphere mixtures, is close to being stable with respect to direct fluid-solid coexistence. From these results, the interesting possibility arises that, for sufficiently soft repulsive particles, this phase transition could become stable. Possible implications for the phase behavior of real colloidal dispersions are discussed.

  7. Vilse, a conserved Rac/Cdc42 GAP mediating Robo repulsion in tracheal cells and axons.

    Science.gov (United States)

    Lundström, Annika; Gallio, Marco; Englund, Camilla; Steneberg, Pär; Hemphälä, Johanna; Aspenström, Pontus; Keleman, Krystyna; Falileeva, Ludmilla; Dickson, Barry J; Samakovlis, Christos

    2004-09-01

    Slit proteins steer the migration of many cell types through their binding to Robo receptors, but how Robo controls cell motility is not clear. We describe the functional analysis of vilse, a Drosophila gene required for Robo repulsion in epithelial cells and axons. Vilse defines a conserved family of RhoGAPs (Rho GTPase-activating proteins), with representatives in flies and vertebrates. The phenotypes of vilse mutants resemble the tracheal and axonal phenotypes of Slit and Robo mutants at the CNS midline. Dosage-sensitive genetic interactions between vilse, slit, and robo mutants suggest that vilse is a component of robo signaling. Moreover, overexpression of Vilse in the trachea of robo mutants ameliorates the phenotypes of robo, indicating that Vilse acts downstream of Robo to mediate midline repulsion. Vilse and its human homolog bind directly to the intracellular domains of the corresponding Robo receptors and promote the hydrolysis of RacGTP and, less efficiently, of Cdc42GTP. These results together with genetic interaction experiments with robo, vilse, and rac mutants suggest a mechanism whereby Robo repulsion is mediated by the localized inactivation of Rac through Vilse.

  8. 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.

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

    Science.gov (United States)

    1976-01-01

    Nigel S. Nicholls Royal Radar Establishment. U.K. David L. Pruitt RCA David V. Turnquist EG&G Inc. Richard L. Verga U.S. Air Force Aero Propulsion...Richard L Verga . Jerrell M. Turner. Wright-Patterson Air Force Base ............................................ 24 Symmetrical Double-Ended Thyratrons In...190 Compact. Ultra High Density. Radar Power Amplifier. Giovanni Scench 4 Paolo Por:io

  10. Impact of writing about mathematics in a humanistic context on mathematical self-concept: A twelfth-grade pilot study

    Directory of Open Access Journals (Sweden)

    Kadijević Đorđe M.

    2004-01-01

    Full Text Available As one’s learning results from a complex interplay among his/her cognitive metacognitive and affective domains, the last of which determines the global context where cognition takes place monitored and controlled by metacognition, the learning outcomes may primarily be interpreted in affective terms. Having in mind a strong positive relation between mathematical self and mathematical achievement as well as that a humanistic approach to mathematics teaching/learning would promote higher mathematical self, this study examined whether writing about mathematics in a humanistic context influences mathematical self. This question was answered by comparing mathematical self of twelfth-grade gymnasium (high-school students who wrote their matura works on mathematical themes (N = 10 with that of their classmates who did that in other subjects (N = 72. A higher mathematical self was found for these ten students, which may be commented with "those who chose to write matura works in mathematics were simply those with higher mathematical self and the writing contributed nothing to the outcome". The values of other control variables measured in grades 9-12 evidence that it is more likely that this finding was influenced by the treatment.

  11. Bypass Flow Computations using a One-Twelfth Symmetric Sector For Normal Operation in a 350 MWth VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato

    2010-10-01

    Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in their construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are computed by varying the gap width from zero to 5 mm, varying the total heat generation rate to examine average and peak radial generation rates and variation of the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation with a gap present. The effect of block shrinkage is actually to decrease maximum fuel temperature compared to a similar reference case.

  12. Bypass Flow Computations using a One-Twelfth Symmetric Sector For Normal Operation in a 350 MWth VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Richard W. Johnson; Hiroyuki Sato

    2012-10-01

    Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in their construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are computed by varying the gap width from zero to 5 mm, varying the total heat generation rate to examine average and peak radial generation rates and variation of the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation with a gap present. The effect of block shrinkage is actually to decrease maximum fuel temperature compared to a similar reference case.

  13. 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

    2017-08-30

    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.

  14. Bypass flow computations using a one-twelfth symmetric sector for normal operation in a 350 MWth prismatic VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Richard W., E-mail: rich.johnson@inl.gov [Idaho National Laboratory, P.O. Box 1625, M.S. 3855, Idaho Falls, ID (United States); Sato, Hiroyuki, E-mail: sato.hiroyuki09@jaea.go.jp [Idaho National Laboratory, P.O. Box 1625, M.S. 3855, Idaho Falls, ID (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer CFD calculations are made of bypass flow between graphite blocks in VHTR. Black-Right-Pointing-Pointer Parameters varied include bypass gap width, heat generation and geometry. Black-Right-Pointing-Pointer Bypass flow causes lateral temperature gradients in graphite block. Black-Right-Pointing-Pointer Bypass flow causes increases in max fuel and coolant temperatures. Black-Right-Pointing-Pointer Bypass flow causes large increase in outlet coolant temperature variation - Abstract: Significant uncertainty exists about the effects of bypass flow in a prismatic gas-cooled very high temperature reactor (VHTR). Bypass flow is the flow in the gaps between prismatic graphite blocks in the core. The gaps are present because of variations in graphite block construction, imperfect installation and expansion and shrinkage from thermal heating and neutron fluence. Calculations are performed using computational fluid dynamics (CFD) for flow of the helium coolant in the gap and coolant channels along with conjugate heat generation and heat transfer in the fuel compacts and core graphite. A commercial CFD code is used for all of the computations. A one-twelfth sector of a standard hexagonal block column is used for the CFD model because of its symmetry. Various scenarios are investigated including varying the gap width, varying the total heat generation between average and peak rates and varying the graphite block geometry to account for the effects of shrinkage caused by irradiation. The calculations are for a 350 MWth prismatic reactor. It is shown that the effect of increasing gap width, while maintaining the same total mass flow rate, causes increased maximum fuel temperature while providing significant cooling to the near-gap region. The maximum outlet coolant temperature variation is increased by the presence of gap flow and also by an increase in total heat generation. The effect of block shrinkage is actually to decrease maximum

  15. pH-programmable self-assembly of plasmonic nanoparticles: hydrophobic interaction versus electrostatic repulsion

    Science.gov (United States)

    Li, Weikun; Kanyo, Istvan; Kuo, Chung-Hao; Thanneeru, Srinivas; He, Jie

    2014-12-01

    We report a general strategy to conceptualize a new design for the pH-programmable self-assembly of plasmonic gold nanoparticles (AuNPs) tethered by random copolymers of poly(styrene-co-acrylic acid) (P(St-co-AA)). It is based on using pH as an external stimulus to reversibly change the surface charge of polymer tethers and to control the delicate balance of interparticle attractive and repulsive interactions. By incorporating -COOH moieties locally within PSt hydrophobic segments, the change in the ionization degree of -COOH moieties can dramatically disrupt the hydrophobic attraction within a close distance. pH acts as a key parameter to control the deprotonation of -COOH moieties and ``programs'' the assembled nanostructures of plasmonic nanoparticles in a stepwise manner. At a higher solution pH where -COOH groups of polymer tethers became highly deprotonated, electrostatic repulsion dominated the self-assembly and favored the formation of end-to-end, anisotropic assemblies, e.g. 1-D single-line chains. At a lower pH, the less deprotonated -COOH groups led to the decrease of electrostatic repulsion and the side-to-side aggregates, e.g. clusters and multi-line chains of AuNPs, became favorable. The pH-programmable self-assembly allowed us to engineer a ``manual'' program for a sequential self-assembly by changing the pH of the solution. We demonstrated that the two-step pH-programmable assembly could generate more sophisticated ``multi-block'' chains using two differently sized AuNPs. Our strategy offers a general means for the programmable design of plasmonic nanoparticles into the specific pre-ordained nanostructures that are potentially useful for the precise control over their plasmon coupling.We report a general strategy to conceptualize a new design for the pH-programmable self-assembly of plasmonic gold nanoparticles (AuNPs) tethered by random copolymers of poly(styrene-co-acrylic acid) (P(St-co-AA)). It is based on using pH as an external stimulus to

  16. Searching for transition paths in multidimensional space with a fixed repulsive bias potential

    Science.gov (United States)

    Trushin, O. S.; Salo, P.; Ala-Nissila, T.; Ying, S. C.

    2004-01-01

    An efficient method for searching for transition paths in a multidimensional configuration space is proposed. It is based on using a fixed, locally repulsive bias potential, which forces the system to move from a given initial state to a different final state. This simple method is very effective in determining nearby configurations and possible transition paths for many-particle systems. Once the approximate transition paths are known, the corresponding activation energies can be computed using, e.g., the nudged elastic band method. The usefulness of the present method is demonstrated for both classical and quantum-mechanical systems.

  17. 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

  18. Observation of Attractive and Repulsive Polarons in a Bose-Einstein Condensate

    DEFF Research Database (Denmark)

    Jørgensen, Nils B.; Wacker, Lars; Skalmstang, Kristoffer Theis

    2016-01-01

    The behavior of a mobile impurity particle interacting with a quantum-mechanical medium is of fundamental importance in physics. Due to the great flexibility of atomic gases, our understanding of the impurity problem has improved dramatically since it was realized experimentally in a particularly...... for an impurity interacting with a Bose-Einstein condensate (BEC). We measure the energy of the impurity both for attractive and repulsive interactions with the BEC, and find excellent agreement with theories that incorporate three-body correlations, both in the weak-coupling limits and across unitarity. Our...

  19. Short-distance repulsion in three-nucleon forces from perturbative quantum chromodynamics

    OpenAIRE

    Aoki, Sinya; Balog, Janos; Weisz, Peter

    2012-01-01

    We investigate the short-distance behavior of three-nucleon forces (3NF) defined through the Nambu–Bethe–Salpeter (NBS) wave functions using the operator product expansion and calculating anomalous dimensions of nine-quark operators in perturbative quantum chromodynamics (QCD). As in the case of NN forces considered previously, we show that 3NF have repulsions at short distance at one-loop, which becomes exact in the short-distance limit thanks to the asymptotic freedom of QCD. Moreover, thes...

  20. Clustering and Synchronization in an Array of Repulsively Coupled Phase Oscillators

    Institute of Scientific and Technical Information of China (English)

    LI Juan; WU Liang; ZHU Shi-Qun

    2007-01-01

    Clustering and synchronization in an array of repulsively coupled phase oscillators are numerically investigated. It is found that oscillators are divided into several clusters according to the symmetry in the structure.Synchronization occurs between oscillators in each cluster, while those oscillators belonging to different clusters remain asynchronous. Such synchronization may collapse for all clusters when the dynamics of only one oscillator is altered properly. The synchronous state may return back after a short period of transient process. This is determined by the strength of the oscillator altered. Its application in the communication of one-to-several is suggested.

  1. Repulsive gravity induced by a conformally coupled scalar field implies a bouncing radiation-dominated universe

    Science.gov (United States)

    Antunes, V.; Novello, M.

    2017-04-01

    In the present work we revisit a model consisting of a scalar field with a quartic self-interaction potential non-minimally (conformally) coupled to gravity (Novello in Phys Lett 90A:347 1980). When the scalar field vacuum is in a broken symmetry state, an effective gravitational constant emerges which, in certain regimes, can lead to gravitational repulsive effects when only ordinary radiation is coupled to gravity. In this case, a bouncing universe is shown to be the only cosmological solution admissible by the field equations when the scalar field is in such broken symmetry state.

  2. The Claustrophobic poetics of the Non-Homes in Repulsion (Roman Polanski, 1965

    Directory of Open Access Journals (Sweden)

    Alberto Román PADILLA DÍAZ

    2017-06-01

    Full Text Available The link between closed and claustrophobic scenery and the twisted mind of the female main characters and their unbalanced psyches is a constant feature in psychological terror movies. Nevertheless, in Roman Polanski’s films, it becomes an obsession which is commonplace throughout his movies. A type of original style is created based on resettings, dark lightings and other architectural transformations of great interest and some semiology, which we might label claustrophobic poetics. The purpose of this paper is to investigate the significance of the scenographicpsychological device of the French director throughout his second film, Repulsion (1965.

  3. Stable suspension and dispersion-induced transitions from repulsive Casimir forces between fluid separated eccentric cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Dalvit, Diego A1 [Los Alamos National Laboratory; Rodriguez, Alejandro W [MASS INST OF TECH; Munday, J N [HARVARD UNIV; Joannopoulos, J D [MASS INST OF TECH

    2008-01-01

    Using accurate numerical methods for finite-size nonplanar objects, we demonstrate a stable mechanical suspension of a silica cylinder within a metallic cylinder separated by ethanol, via a repulsive Casimir force between the silica and the metal. We investigate cylinders with both circular and square cross sections, and show that the latter exhibit a stable orientation as well as a stable position, employing a new method to accurately compute Casimir torques for finite objects. Furthermore, the stable orientation of the square cylinder is shown to undergo an unusual 45 transition as a function of the separation lengthscale, and this transition is explained as a consequence of material dispersion.

  4. Avoiding self-repulsion in density functional description of biased molecular junctions

    Energy Technology Data Exchange (ETDEWEB)

    Baer, Roi [Department of Physical Chemistry and Lise Meitner Minerva-Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)], E-mail: roi.baer@huji.ac.il; Livshits, Ester [Department of Physical Chemistry and Lise Meitner Minerva-Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Neuhauser, Daniel [Department of Physical Chemistry and Lise Meitner Minerva-Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)], E-mail: dxn@chem.ucla.edu

    2006-10-26

    We examine the effects of self-repulsion on the predictions of charge distribution in biased molecular junctions by the local density functional theory methods. This is done using a functional with explicit long-range exchange term effects [R. Baer, D. Neuhauser, Phys. Rev. Lett. 94 (2005) 043002]. We discuss in detail the new density functional, pointing out some of the remaining difficulties in the theory. We find that in weakly coupled junctions (the typical molecular electronics case) local-density functionals fail to describe correctly the charge distribution in the intermediate bias regime.

  5. The repulsive nature of naked singularities from the point of view of quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Batic, D.; Chin, D. [University of West Indies, Department of Mathematics, Kingston 6 (Jamaica); Nowakowski, M. [Universidad de los Andes, Departamento de Fisica, Cra. 1E No. 18A-10, Bogota (Colombia)

    2011-04-15

    We use the Dirac equation coupled to a background metric to examine what happens to quantum-mechanical observables like the probability density and the radial current in the vicinity of a naked singularity of the Reissner-Nordstroem type. We find that the wave function of the Dirac particle is regular in the point of the singularity. We show that the probability density is exactly zero at the singularity reflecting quantum-mechanically the repulsive nature of the naked singularity. Furthermore, the surface integral of the radial current over a sphere in the vicinity of the naked singularity turns out to be also zero. (orig.)

  6. Interplay between electron-phonon interaction and Hubbard repulsion: Bipolaron formation

    Energy Technology Data Exchange (ETDEWEB)

    Nath, S.; Mondal, N. S.; Ghosh, N. K., E-mail: nanda.ku@rediffmail.com [Department of Physics, University of Kalyani, Kalyani-741235, West Bengal (India)

    2015-06-24

    In the weak coupling limit, the 2D Hubbard model extended by on-site (local) and inter-site (long range) electron-phonon (EP) interaction has been investigated within Lanczos method of exact diagonalization (ED). On-site (S0) bipolaron formation has been favored by on-site EP interaction induced effective attraction between electrons. But, inter-site phonon mediated interaction between electrons helps to form both S0 and neighboring site (S1) bipolaron. It is further observed that both types of bipolaron formation are suppressed by on-site Hubbard repulsion.

  7. Oscillator death induced by amplitude-dependent coupling in repulsively coupled oscillators

    Science.gov (United States)

    Liu, Weiqing; Xiao, Guibao; Zhu, Yun; Zhan, Meng; Xiao, Jinghua; Kurths, Jürgen

    2015-05-01

    The effects of amplitude-dependent coupling on oscillator death (OD) are investigated for two repulsively coupled Lorenz oscillators. Based on numerical simulations, it is shown that as constraint strengths on the amplitude-dependent coupling change, an oscillatory state may undergo a transition to an OD state. The parameter regimes of the OD domain are theoretically determined, which coincide well with the numerical results. An electronic circuit is set up to exhibit the transition process to the OD state with an amplitude-dependent coupling. These findings may have practical importance on chaos control and oscillation depression.

  8. A summary of the Proceedings of the Twelfth International Symposium on the Neurobiology and Neuroendocrinology of Aging, Bregenz, Austria July 27-August 1, 2014.

    Science.gov (United States)

    Brown-Borg, Holly M; Borg, Kurt E

    2015-08-01

    A summary of the Twelfth International Symposium on the Neurobiology and Neuroendocrinology of Aging that was held July 27-August 1, 2014 in Bregenz, Austria, is presented. Fifteen of the speakers that presented at the conference submitted review papers covering the topic of their presentation as well as an overview of their respective fields and are included in this special issue. The abstracts from each poster presentation as well as seven of the speakers' abstracts are also included at the end of the preface to the special issue.

  9. 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.

  10. A new model of repulsive force in eddy current separation for recovering waste toner cartridges.

    Science.gov (United States)

    Ruan, Jujun; Xu, Zhenming

    2011-08-15

    Eddy current separation (ECS) is an efficient method for separating aluminum from plastic in crushed waste toner cartridge (TCs). However, in China, ECS quality of aluminum from plastic is rather low in production practice. Repeating separation even manual sorting is required in the production. Improving separation quality of aluminum has been the pressing problem in the recovery of waste TCs. Furthermore, improving ECS quality can reduce the secondary-pollution (furan and dioxin) brought by plastic in later smelting process for the purification of recovered aluminum. Thus, a new model of repulsive force containing impact factors (machine: B(r), k, R, S(m), B(m); material: S(p), V, γ; and operation: ω(m), v, δ) of the separation process was constructed for guiding the ECS process of waste TCs recovering in this paper. For testing whether the model of repulsive force was suitable to guide the ECS, calculation and experiment of detachment angle of aluminum flake were studied. The calculation results of the detachment angles were agreed with the testing experiment. It indicates that the model is suitable for guiding the ECS of waste TCs recovering. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    CERN Document Server

    Nyambuya, G G

    2010-01-01

    This paper is part of a series on the Azimuthally Symmetric Theory of Gravitation (ASTG) which is built on Laplace-Poisson's well known equation. 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 emer...

  12. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Zhou Shi-Qi

    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.

  14. Aggregation pattern transitions by slightly varying the attractive/repulsive function.

    Directory of Open Access Journals (Sweden)

    Zhao Cheng

    Full Text Available Among collective behaviors of biological swarms and flocks, the attractive/repulsive (A/R functional links between particles play an important role. By slightly changing the cutoff distance of the A/R function, a drastic transition between two distinct aggregation patterns is observed. More precisely, a large cutoff distance yields a liquid-like aggregation pattern where the particle density decreases monotonously from the inside to the outwards within each aggregated cluster. Conversely, a small cutoff distance produces a crystal-like aggregation pattern where the distance between each pair of neighboring particles remains constant. Significantly, there is an obvious spinodal in the variance curve of the inter-particle distances along the increasing cutoff distances, implying a legible transition pattern between the liquid-like and crystal-like aggregations. This work bridges the aggregation phenomena of physical particles and swarming of organisms in nature upon revealing some common mechanism behind them by slightly varying their inter-individual attractive/repulsive functions, and may find its potential engineering applications, for example, in the formation design of multi-robot systems and unmanned aerial vehicles (UAVs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, S., E-mail: ohashi@ipcku.kansai-u.ac.j [Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680 (Japan); Kobayashi, S. [Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2009-10-15

    Magnetic levitation using the pinning force of the YBaCuO high-T{sub 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.

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

    Science.gov (United States)

    Ohashi, S.; Kobayashi, S.

    2009-10-01

    Magnetic levitation using the pinning force of the YBaCuO high- Tc 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.

  17. Dynamical Generation of a Repulsive Vector Contribution to the Quark Pressure

    CERN Document Server

    Restrepo, Tulio E; Pinto, Marcus Benghi; Ferrari, Gabriel N

    2014-01-01

    Lattice QCD results for the coefficient $c_2$ appearing in the Taylor expansion of the pressure show that this quantity raises with the temperature towards the Stefan-Boltzmann limit. On the other hand, model approximations predict that when a vector repulsion, parametrized by $G_V$, is present this coefficient reaches a maximum just after $T_c$ and then deviates from the lattice predictions. Recently, this discrepancy has been used as a guide to constrain the (presently unknown) value of $G_V$ within the framework of effective models at large-$N_c$ (LN). In the present investigation we show that, due to finite $N_c$ effects, $c_2$ may also develop a maximum even when $G_V=0$ since a vector repulsive term can be dynamically generated by exchange type of radiative corrections. Here we apply the the Optimized Perturbation Theory (OPT) method to the two flavor Polyakov--Nambu--Jona-Lasinio model (at $G_V=0$) and compare the results with those furnished by lattice simulations an by the LN approximation at $G_V=0$...

  18. 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.)

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

    Directory of Open Access Journals (Sweden)

    Kaoru Miura

    2011-01-01

    Full Text Available 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.

  20. Parametric study of the vibration-induced repulsion or attraction force on a particle in a viscous fluid cell.

    Science.gov (United States)

    Saadatmand, Mehrrad; Kawaji, Masahiro

    2014-04-01

    Experiments and three-dimensional direct numerical simulations were performed to investigate the effects of physical parameters on the repulsion or attraction force affecting the motion of a particle oscillating near a solid wall of a fluid cell under microgravity. The following physical parameters were investigated: fluid cell amplitude, fluid and particle densities, angular frequency of the cell vibration, initial distance between the particle centroid and the closest cell wall, particle radius, and dynamic viscosity. Based on the simulations, a nondimensional relation was developed to relate those physical parameters to the repulsion or attraction force affecting the particle. The relation shows that the repulsion or attraction force is increased by the increase in the cell vibration amplitude and frequency and also the force direction would change from attraction to repulsion above a threshold fluid viscosity. Relations to other physical parameters were also studied and are reported. This paper follows our previous work on the physical mechanism of observed repulsion force on a particle in a viscous fluid cell [M. Saadatmand and M. Kawaji, Phys. Rev. E 88, 023019 (2013)].

  1. Duplication of a Single Neuron in C. elegans Reveals a Pathway for Dendrite Tiling by Mutual Repulsion

    Directory of Open Access Journals (Sweden)

    Zhiqi Candice Yip

    2016-06-01

    Full Text Available Simple cell-cell interactions can give rise to complex cellular patterns. For example, neurons of the same type can interact to create a complex patchwork of non-overlapping dendrite arbors, a pattern known as dendrite tiling. Dendrite tiling often involves mutual repulsion between neighboring neurons. While dendrite tiling is found across nervous systems, the nematode Caenorhabditis elegans has a relatively simple nervous system with few opportunities for tiling. Here, we show that genetic duplication of a single neuron, PVD, is sufficient to create dendrite tiling among the resulting ectopic neurons. We use laser ablation to show that this tiling is mediated by mutual repulsion between neighbors. Furthermore, we find that tiling requires a repulsion signal (UNC-6/Netrin and its receptors UNC-40/DCC and UNC-5 that normally patterns the PVD dendrite arbor. These results demonstrate that an apparently complex cellular pattern can emerge in a simple nervous system merely by increasing neuron number.

  2. Structure, stability, and formation pathways of colloidal gels in systems with short-range attraction and long-range repulsion.

    Science.gov (United States)

    van Schooneveld, Matti M; de Villeneuve, Volkert W A; Dullens, Roel P A; Aarts, Dirk G A L; Leunissen, Mirjam E; Kegel, Willem K

    2009-04-09

    We study colloidal gels formed upon centrifugation of dilute suspensions of spherical colloids (radius 446 nm) that interact through a long-range electrostatic repulsion (Debye length approximately 850 nm) and a short-range depletion attraction (approximately 12.5 nm), by means of confocal scanning laser microscopy (CSLM). In these systems, at low colloid densities, colloidal clusters are stable. Upon increasing the density by centrifugation, at different stages of cluster formation, we show that colloidal gels are formed that significantly differ in structure. While significant single-particle displacements do not occur on the hour time scale, the different gels slowly evolve within several weeks to a similar structure that is at least stable for over a year. Furthermore, while reference systems without long-range repulsion collapse into dense glassy states, the repulsive colloidal gels are able to support external stress in the form of a centrifugal field of at least 9g.

  3. Decreased levels of repulsive guidance molecule A in association with beneficial effects of repeated intrathecal triamcinolone acetonide application in progressive multiple sclerosis patients.

    Science.gov (United States)

    Müller, Thomas; Barghorn, Stefan; Lütge, Sven; Haas, Thomas; Mueller, Reinhold; Gerlach, Bjoern; Öhm, Gabi; Eilert, Katrin; Trommer, Isabel; Mueller, Bernhard K

    2015-06-01

    Repeated intrathecal application of the sustained release steroid triamcinolone acetonide is beneficial in progressive multiple sclerosis patients. Its putative regenerative effect may involve regulation of the repulsive guidance molecule A synthesis. This protein inhibits axonal regeneration and functional recovery. Objectives were to demonstrate the efficacy of four triamcinolone applications every other day in association with repulsive guidance molecule A levels in cerebrospinal fluid. Clinical evaluation was performed at baseline and on each day after a triamcinolone administration in 25 progressive multiple sclerosis patients. Repulsive guidance molecule A concentrations were determined before each triamcinolone application by western blot analysis with quantification. Clinical scores for multiple sclerosis improved, and the maximum walking distance and speed ameliorated in 17 patients. Repulsive guidance molecule A levels declined in these responders. The remaining patients showed no prompt clinical benefit and no decrease of repulsive guidance molecule A concentrations. Decline of repulsive guidance molecule A may reflect regeneration and functional recovery by triamcinolone in progressive multiple sclerosis patients.

  4. Answering Top-k Queries Over a Mixture of Attractive and Repulsive Dimensions

    CERN Document Server

    Ranu, Sayan

    2011-01-01

    In this paper, we formulate a top-k query that compares objects in a database to a user-provided query object on a novel scoring function. The proposed scoring function combines the idea of attractive and repulsive dimensions into a general framework to overcome the weakness of traditional distance or similarity measures. We study the properties of the proposed class of scoring functions and develop efficient and scalable index structures that index the isolines of the function. We demonstrate various scenarios where the query finds application. Empirical evaluation demonstrates a performance gain of one to two orders of magnitude on querying time over existing state-of-the-art top-k techniques. Further, a qualitative analysis is performed on a real dataset to highlight the potential of the proposed query in discovering hidden data characteristics.

  5. Cosmological evolution of a complex scalar field with repulsive or attractive self-interaction

    Science.gov (United States)

    Suárez, Abril; Chavanis, Pierre-Henri

    2017-03-01

    We study the cosmological evolution of a complex scalar field with a self-interaction potential V (|φ |2) , possibly describing self-gravitating Bose-Einstein condensates, using a fully general relativistic treatment. We generalize the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field approximation developed in our previous paper [A. Suárez and P.-H. Chavanis, Phys. Rev. D 92, 023510 (2015), 10.1103/PhysRevD.92.023510]. We establish the general equations governing the evolution of a spatially homogeneous complex scalar field in an expanding background. We show how they can be simplified in the fast oscillation regime (equivalent to the Thomas-Fermi, or semiclassical, approximation) and derive the equation of state of the scalar field in parametric form for an arbitrary potential V (|φ |2) . We explicitly consider the case of a quartic potential with repulsive or attractive self-interaction. For repulsive self-interaction, the scalar field undergoes a stiff matter era followed by a pressureless dark matter era in the weakly self-interacting regime and a stiff matter era followed by a radiationlike era and a pressureless dark matter era in the strongly self-interacting regime. For attractive self-interaction, the scalar field undergoes an inflation era followed by a stiff matter era and a pressureless dark matter era in the weakly self-interacting regime and an inflation era followed by a cosmic stringlike era and a pressureless dark matter era in the strongly self-interacting regime (the inflation era is suggested, not demonstrated). We also find a peculiar branch on which the scalar field emerges suddenly at a nonzero scale factor with a finite energy density. At early times, it behaves as a gas of cosmic strings. At later times, it behaves as dark energy with an almost constant energy density giving rise to a de Sitter evolution. This is due to spintessence. We derive the effective cosmological constant produced by the scalar

  6. Symbolic-numerical Algorithm for Generating Cluster Eigenfunctions: Tunneling of Clusters Through Repulsive Barriers

    CERN Document Server

    Vinitsky, Sergue; Chuluunbaatar, Ochbadrakh; Rostovtsev, Vitaly; Hai, Luong Le; Derbov, Vladimir; Krassovitskiy, Pavel

    2013-01-01

    A model for quantum tunnelling of a cluster comprising A identical particles, coupled by oscillator-type potential, through short-range repulsive potential barriers is introduced for the first time in the new symmetrized-coordinate representation and studied within the s-wave approximation. The symbolic-numerical algorithms for calculating the effective potentials of the close-coupling equations in terms of the cluster wave functions and the energy of the barrier quasistationary states are formulated and implemented using the Maple computer algebra system. The effect of quantum transparency, manifesting itself in nonmonotonic resonance-type dependence of the transmission coefficient upon the energy of the particles, the number of the particles A=2,3,4, and their symmetry type, is analyzed. It is shown that the resonance behavior of the total transmission coefficient is due to the existence of barrier quasistationary states imbedded in the continuum.

  7. Cosmological evolution of a complex scalar field with repulsive or attractive self-interaction

    CERN Document Server

    Suárez, Abril

    2016-01-01

    We study the cosmological evolution of a complex scalar field with a self-interaction potential $V(|\\varphi|^2)$, possibly describing self-gravitating Bose-Einstein condensates, using a fully general relativistic treatment. We generalize the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field approximation developed in our previous paper. We establish the general equations governing the evolution of a spatially homogeneous complex scalar field in an expanding background. We show how they can be simplified in the fast oscillation regime and derive the equation of state of the scalar field in parametric form for an arbitrary potential. We explicitly consider the case of a quartic potential with repulsive or attractive self-interaction and determine the phase diagram of the scalar field. We show that the transition between the weakly self-interacting regime and the strongly self-interacting regime depends on how the scattering length of the bosons compares with their effective Sc...

  8. Bright and Dark Solitons and Breathers in Strongly Repulsive Bose-Einstein Condensates

    CERN Document Server

    Reinhardt, William P; Robbins, Bryce; Clark, Charles W

    2011-01-01

    Collisional dynamics of solitary matter waves of superfluid hard core bosons, consisting of dark and bright non-linear waves as well as supersonic periodic trains, reveals remarkable richness and coherence, with the phase of the condensate playing a key role. Depending upon the condensate density and their relative velocity, two distinctive collisional types emerge: the intuitively expected repulsive collisions due to the hard core boson constraint; and, also collisions in which they "pass through" one another. In addition to confirming the soliton status of both bright and dark solitary waves, our studies reveal a variety of multi-solitons including multiple families of breathers, that can be produced and precisely controlled via quantum phase engineering.

  9. 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.

  10. Designing convex repulsive pair potentials that favor assembly of kagome and snub square lattices

    Science.gov (United States)

    Piñeros, William D.; Baldea, Michael; Truskett, Thomas M.

    2016-08-01

    Building on a recently introduced inverse strategy, isotropic and convex repulsive pair potentials were designed that favor assembly of particles into kagome and equilateral snub square lattices. The former interactions were obtained by a numerical solution of a variational problem that maximizes the range of density for which the ground state of the potential is the kagome lattice. Similar optimizations targeting the snub square lattice were also carried out, employing a constraint that required a minimum chemical potential advantage of the target over select competing structures. This constraint helped to discover isotropic interactions that meaningfully favored the snub square lattice as the ground state structure despite the asymmetric spatial distribution of particles in its coordination shells and the presence of tightly competing structures. Consistent with earlier published results [W. Piñeros et al., J. Chem. Phys. 144, 084502 (2016)], enforcement of greater chemical potential advantages for the target lattice in the interaction optimization led to assemblies with enhanced thermal stability.

  11. Strong energy condition and the repulsive character of f(R) gravity

    CERN Document Server

    Santos, Crislane S; Capozziello, Salvatore; Alcaniz, Jailson S

    2016-01-01

    The Raychaudhuri equation enables to examine the whole spacetime structure without specific solutions of Einstein's equations, playing a central role for the understanding of the gravitational interaction in Cosmology. In General Relativity, without considering a cosmological constant, a non-positive contribution in the Raychaudhuri equation is usually interpreted as the manifestation of the attractive character of gravity. In this case, particular energy conditions -- indeed the strong energy condition -- must be assumed in order to guarantee the attractive character. In the context of f(R) gravity, however, even assuming the standard energy conditions one may have a positive contribution to the Raychaudhuri equation. Besides providing a simple way to explain the observed cosmic acceleration, this fact opens the possibility of a repulsive character of this kind of gravity. In order to discuss physical bounds on f(R) models, we address the attractive/non-attractive character of f(R) gravity considering the Ra...

  12. Bright Solitons in an Atomic Tunnel Array with Either Attractive or Repulsive Atom-Atom Interactions

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-Xue; YOU Jun; WU Ying

    2004-01-01

    @@ Taking a coherent state representation, we derive the nonlinear Schrodinger-type differential-difference equations from the quantized model of an array of traps containing Bose-Einstein condensates and linked by the tunnelling process among the adjacent traps. It is shown that no matter whether two-body interactions among atoms are repulsive or attractive, a nearly uniform atom distribution can evolve into a bright soliton-type localized ensemble of atoms and a lump of atom distribution can also be smeared out by redistributing atoms among traps under appropriate initial phase differences of atoms in adjacent traps. These two important features originate from the tailoring effect of the initial phase conditions in coherent tunnelling processes, which differs crucially from the previous tailoring effect coming mainly from the periodicity of optical lattices.

  13. Inter-domain dipolar repulsion in lipid monolayers with phase coexistence

    CERN Document Server

    Fiori, Elena Rufeil; Banchio, Adolfo J

    2015-01-01

    A great variety of biologically relevant monolayers present phase coexistence characterized by domains formed by lipids in a long-range ordered phase state dispersed in a continuous, disordered phase. Because of the difference in surface densities the domains possess an excess dipolar density with respect to the surrounding liquid phase. In this work we propose an alternative method to measure the dipolar repulsion for neutral lipid monolayers. The procedure is based on the comparison of the radial distribution function, g(r), from experiments and Brownian dynamic (BD) simulations. The domains were modeled as disks with surface dipolar density, whose strength was varied to best describe the experimentally determined monolayer structure. For comparison, the point dipole approximation was also studied. As an example, we applied the method for mixed monolayers with different proportions of distearoylphosphatidylcholine (DSPC) and dimyristoylphosphatidylcholine (DMPC) and obtained the excess dipolar density, whic...

  14. Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory.

    Science.gov (United States)

    Zhang, Xichao; Zhao, G P; Fangohr, Hans; Liu, J Ping; Xia, W X; Xia, J; Morvan, F J

    2015-01-06

    Magnetic skyrmions are promising for building next-generation magnetic memories and spintronic devices due to their stability, small size and the extremely low currents needed to move them. In particular, skyrmion-based racetrack memory is attractive for information technology, where skyrmions are used to store information as data bits instead of traditional domain walls. Here we numerically demonstrate the impacts of skyrmion-skyrmion and skyrmion-edge repulsions on the feasibility of skyrmion-based racetrack memory. The reliable and practicable spacing between consecutive skyrmionic bits on the racetrack as well as the ability to adjust it are investigated. Clogging of skyrmionic bits is found at the end of the racetrack, leading to the reduction of skyrmion size. Further, we demonstrate an effective and simple method to avoid the clogging of skyrmionic bits, which ensures the elimination of skyrmionic bits beyond the reading element. Our results give guidance for the design and development of future skyrmion-based racetrack memory.

  15. Electrostatic repulsion between cucurbit[7]urils can be overcome in [3]pseudorotaxane without adding salts.

    Science.gov (United States)

    Pessêgo, M; Moreira, J A; Rosa da Costa, A M; Corrochano, P; Poblete, F J; Garcia-Rio, L

    2013-04-19

    The host-guest chemistry between cucurbit[7]uril (CB7) and a series of bolaform (Bn) surfactants with different chain lengths, n = 12-22, was the target of our study. [3]Pseudorotaxanes are formed when the alkyl chain of the bolaform has more than 14 carbon atoms. In these cases, two CB7 molecules can be accommodated between the two head groups of the bolaform without addition of electrolytes to the medium. In the case of a bolaform with 12 carbon atoms, the electrostatic repulsion between the carbonyl groups of the CB7 molecules avoids the threading of a second CB7 molecule yielding a mixed structure formed by a [2]pseudorotaxane and an external host-guest complex. The assembly behavior was investigated using NMR spectroscopy, isothermal titration calorimetry (ITC), and kinetic measurements.

  16. Coexistence of Multiple Phases in Magnetized Quark Matter with Vector Repulsion

    CERN Document Server

    Denke, Robson Z

    2015-01-01

    We explore the phase structure of dense magnetized quark matter when a repulsive vector interaction, parametrized by $G_V$, is present. Our results show that for a given magnetic field intensity ($B$) one may find a value of $G_V$ for which quark matter may coexist at three different baryonic density values leading to the appearance of two triple points in the phase diagram which have not been observed before. Another novel result is that at high pressure and low temperature we observe a first order transition which presents a negative slope in the $P-T$ that is reminiscent of the solid-liquid transition line observed within the water phase diagram. These unusual patterns occur for $G_V$ and $B$ values which lie within the range presently considered in many investigations related to the study of magnetars.

  17. Superconductivity in repulsively interacting fermions on a diamond chain: Flat-band-induced pairing

    Science.gov (United States)

    Kobayashi, Keita; Okumura, Masahiko; Yamada, Susumu; Machida, Masahiko; Aoki, Hideo

    2016-12-01

    To explore whether a flat-band system can accommodate superconductivity, we consider repulsively interacting fermions on the diamond chain, a simplest possible quasi-one-dimensional system that contains a flat band. Exact diagonalization and the density-matrix renormalization group are used to show that we have a significant binding energy of a Cooper pair with a long-tailed pair-pair correlation in real space when the total band filling is slightly below 1/3, where a filled dispersive band interacts with the flat band that is empty but close to EF. Pairs selectively formed across the outer sites of the diamond chain are responsible for the pairing correlation. At exactly 1/3-filling an insulating phase emerges, where the entanglement spectrum indicates the particles on the outer sites are highly entangled and topological. These come from a peculiarity of the flat band in which "Wannier orbits" are not orthogonalizable.

  18. Bubble-bound state of triple-stranded DNA: Efimov physics in DNA with repulsion

    Science.gov (United States)

    Maji, Jaya; Seno, Flavio; Trovato, Antonio; Bhattacharjee, Somendra M.

    2017-07-01

    The presence of a thermodynamic phase of a three-stranded DNA, namely, a mixed phase of bubbles of two bound strands and a single one, is established for large dimensions (d≥slant 5 ) by using exact real space renormalization group transformations and exact computations of specific heat for finite length chains. Similar exact computations for the fractal Sierpinski gasket of dimension d  <  2 establish the stability of the phase in the presence of a repulsive three chain interaction. Although, for d  <  2, cooperativity factors for bubbles or noncrossing conditions are needed for the melting transition, the mixed phase may exist even in absence of those. In contrast to the Efimov DNA, where three strands are bound though no two are bound, the mixed phase appears at temperatures less than the two chain melting temperature. Both the Efimov-DNA and the mixed phase are formed essentially due to the strand exchange mechanism.

  19. Repulsive Interaction of Sulfide Layers on Compressor Impeller Blades Remanufactured Through Plasma Spray Welding

    Science.gov (United States)

    Chang, Y.; Zhou, D.; Wang, Y. L.; Huang, H. H.

    2016-12-01

    This study investigated the repulsive interaction of sulfide layers on compressor impeller blades remanufactured through plasma spray welding (PSW). Sulfide layers on the blades made of FV(520)B steel were prepared through multifarious corrosion experiments, and PSW was utilized to remanufacture blade specimens. The specimens were evaluated through optical microscopy, scanning electron microscopy, energy-dispersive spectroscopy, 3D surface topography, x-ray diffraction, ImageJ software analysis, Vicker's micro-hardness test and tensile tests. Results showed a large number of sulfide inclusions in the fusion zone generated by sulfide layers embodied into the molten pool during PSW. These sulfide inclusions seriously degraded the mechanical performance of the blades remanufactured through PSW.

  20. Multimetric extension of the PPN formalism: experimental consistency of repulsive gravity

    CERN Document Server

    Hohmann, Manuel

    2010-01-01

    Recently we discussed a multimetric gravity theory containing several copies of standard model matter each of which couples to its own metric tensor. This construction contained dark matter sectors interacting repulsively with the visible matter sector, and was shown to lead to cosmological late-time acceleration. In order to test the theory with high-precision experiments within the solar system we here construct a simple extension of the parametrized post-Newtonian (PPN) formalism for multimetric gravitational backgrounds. We show that a simplified version of this extended formalism allows the computation of a subset of the PPN parameters from the linearized field equations. Applying the simplified formalism we find that the PPN parameters of our theory do not agree with the observed values, but we are able to improve the theory so that it becomes consistent with experiments of post-Newtonian gravity and still features its promising cosmological properties.

  1. Multimetric extension of the parametrized post-Newtonian formalism: Experimental consistency of repulsive gravity

    Science.gov (United States)

    Hohmann, Manuel; Wohlfarth, Mattias N. R.

    2010-10-01

    Recently we discussed a multimetric gravity theory containing several copies of standard model matter each of which couples to its own metric tensor. This construction contained dark matter sectors interacting repulsively with the visible matter sector and was shown to lead to cosmological late-time acceleration. In order to test the theory with high-precision experiments within the solar system, we here construct a simple extension of the parametrized post-Newtonian (PPN) formalism for multimetric gravitational backgrounds. We show that a simplified version of this extended formalism allows the computation of a subset of the PPN parameters from the linearized field equations. Applying the simplified formalism we find that the PPN parameters of our theory do not agree with the observed values, but we are able to improve the theory so that it becomes consistent with experiments of post-Newtonian gravity and still features its promising cosmological properties.

  2. Analysis and improvement in repulsive force of 630 A frame Moulded Case Circuit Breaker (MCCB

    Directory of Open Access Journals (Sweden)

    Digpalsinh Parmar

    2016-09-01

    Full Text Available Moulded Case Circuit Breaker (MCCB is a protective device used for low voltage protection in the range of 12–1250 A. It is having fast breaking and making ability due to special contact structure. In case of transformer it is generally placed in secondary side and in case of motor protection it is used as backup protection. The existing design is suffering from chattering of contact tip which lead to erosion and in turn affect electrical life. It also reduces interrupting/breaking capacity of MCCB. In this paper, detailed study of the factors and constraints related to repulsion threshold current (Irp and consistency of magnetic release for 630 A MCCB is carried out using Finite Element tool JMAG to find out limitations and scope of design improvements in existing design. The proposed suggestion is validated by testing.

  3. 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.

  4. 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.

  5. Optimal strategies for driving a mobile agent in a "guidance by repulsion" model

    Science.gov (United States)

    Escobedo, R.; Ibañez, A.; Zuazua, E.

    2016-10-01

    We present a guidance by repulsion model based on a driver-evader interaction where the driver, assumed to be faster than the evader, follows the evader but cannot be arbitrarily close to it, and the evader tries to move away from the driver beyond a short distance. The key ingredient allowing the driver to guide the evader is that the driver is able to display a circumvention maneuver around the evader, in such a way that the trajectory of the evader is modified in the direction of the repulsion that the driver exerts on the evader. The evader can thus be driven towards any given target or along a sufficiently smooth path by controlling a single discrete parameter acting on driver's behavior. The control parameter serves both to activate/deactivate the circumvention mode and to select the clockwise/counterclockwise direction of the circumvention maneuver. Assuming that the circumvention mode is more expensive than the pursuit mode, and that the activation of the circumvention mode has a high cost, we formulate an optimal control problem for the optimal strategy to drive the evader to a given target. By means of numerical shooting methods, we find the optimal open-loop control which reduces the number of activations of the circumvention mode to one and which minimizes the time spent in the active mode. Our numerical simulations show that the system is highly sensitive to small variations of the control function, and that the cost function has a nonlinear regime which contributes to the complexity of the behavior of the system, so that a general open-loop control would not be of practical interest. We then propose a feedback control law that corrects from deviations while preventing from an excessive use of the circumvention mode, finding numerically that the feedback law significantly reduces the cost obtained with the open-loop control.

  6. Multiple replica repulsion technique for efficient conformational sampling of biological systems.

    Science.gov (United States)

    Malevanets, Anatoly; Wodak, Shoshana J

    2011-08-17

    Here, we propose a technique for sampling complex molecular systems with many degrees of freedom. The technique, termed "multiple replica repulsion" (MRR), does not suffer from poor scaling with the number of degrees of freedom associated with common replica exchange procedures and does not require sampling at high temperatures. The algorithm involves creation of multiple copies (replicas) of the system, which interact with one another through a repulsive potential that can be applied to the system as a whole or to portions of it. The proposed scheme prevents oversampling of the most populated states and provides accurate descriptions of conformational perturbations typically associated with sampling ground-state energy wells. The performance of MRR is illustrated for three systems of increasing complexity. A two-dimensional toy potential surface is used to probe the sampling efficiency as a function of key parameters of the procedure. MRR simulations of the Met-enkephalin pentapeptide, and the 76-residue protein ubiquitin, performed in presence of explicit water molecules and totaling 32 ns each, investigate the ability of MRR to characterize the conformational landscape of the peptide, and the protein native basin, respectively. Results obtained for the enkephalin peptide reflect more closely the extensive conformational flexibility of this peptide than previously reported simulations. Those obtained for ubiquitin show that conformational ensembles sampled by MRR largely encompass structural fluctuations relevant to biological recognition, which occur on the microsecond timescale, or are observed in crystal structures of ubiquitin complexes with other proteins. MRR thus emerges as a very promising simple and versatile technique for modeling the structural plasticity of complex biological systems. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  7. 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.

  8. Repulsive interatomic potentials for noble gas bombardment of Cu and Ni targets

    Energy Technology Data Exchange (ETDEWEB)

    Karolewski, M.A. [Department of Chemistry, University of Brunei Darussalam, Jalan Tungku Link, Gadong BE 1410 (Brunei Darussalam)]. E-mail: mkarol@fos.ubd.edu.bn

    2006-01-15

    Interatomic potentials that are relevant for noble gas bombardment of Cu and Ni targets have been calculated in the energy region below 10 keV. Potentials are calculated for the diatomic species: NeCu, ArCu, KrCu, Cu{sub 2}, ArNi, Ni{sub 2} and NiCu. The calculations primarily employ density functional theory (with the B3LYP exchange-correlation functional). Potential curves derived from Hartree-Fock theory calculations are also discussed. Scalar relativistic effects have been included via the second-order Douglas-Kroll-Hess (DKH2) method. On the basis of a variational argument, it can be shown that the predicted potential curves represent an upper limit to the true potential curves. The potentials provide a basis for assessing corrections required to the ZBL and Moliere screened Coulombic potentials, which are typically found to be too repulsive below 1-2 keV. These corrections significantly improve the accuracy of the sputter yield predicted by molecular dynamics for Ni(1 0 0), whereas the sputter yield predicted for Cu(1 0 0) is negligibly affected. The validity of the pair potential approximation in the repulsive region of the potential is tested by direct calculation of the potentials arising from the interaction of either an Ar or Cu atom with a Cu{sub 3} cluster. The pairwise approximation represents the Ar-Cu{sub 3} potential energy function with an error <3 eV at all Ar-Cu{sub 3} separations. For Cu-Cu{sub 3}, the pairwise approximation underestimates the potential by ca. 10 eV when the interstitial atom is located near the centre of the cluster.

  9. Self-accelerated universe induced by repulsive effects as an alternative to dark energy and modified gravities

    CERN Document Server

    Luongo, Orlando

    2015-01-01

    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 \\emph{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 d...

  10. 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

    The colloidal stability of charged particles in suspension is often controlled by electrostatic repulsion, which can be rationalized in a semi-quantitative way by the DLVO theory. In the current study, we investigate this approach towards understanding irreversible protein aggregation, using Baci...

  11. Slit-Dependent Endocytic Trafficking of the Robo Receptor Is Required for Son of Sevenless Recruitment and Midline Axon Repulsion.

    Directory of Open Access Journals (Sweden)

    Rebecca K Chance

    2015-09-01

    Full Text Available Understanding how axon guidance receptors are activated by their extracellular ligands to regulate growth cone motility is critical to learning how proper wiring is established during development. Roundabout (Robo is one such guidance receptor that mediates repulsion from its ligand Slit in both invertebrates and vertebrates. Here we show that endocytic trafficking of the Robo receptor in response to Slit-binding is necessary for its repulsive signaling output. Dose-dependent genetic interactions and in vitro Robo activation assays support a role for Clathrin-dependent endocytosis, and entry into both the early and late endosomes as positive regulators of Slit-Robo signaling. We identify two conserved motifs in Robo's cytoplasmic domain that are required for its Clathrin-dependent endocytosis and activation in vitro; gain of function and genetic rescue experiments provide strong evidence that these trafficking events are required for Robo repulsive guidance activity in vivo. Our data support a model in which Robo's ligand-dependent internalization from the cell surface to the late endosome is essential for receptor activation and proper repulsive guidance at the midline by allowing recruitment of the downstream effector Son of Sevenless in a spatially constrained endocytic trafficking compartment.

  12. Integrable one-dimensional N-component fermion model with correlated hopping and hard-core repulsion

    Energy Technology Data Exchange (ETDEWEB)

    Yue Ruihong. E-mail: yue@phy.nw.ed.nc; Schlottmann, P. E-mail: schlottm@phy.fsu.edu

    2002-12-30

    The N-component Bariev model for correlated hopping and a hard-core repulsion is shown to be integrable in one dimension. The solution of the model is obtained within the framework of nested Bethe Ansatz. The ground state integral equations for the densities of the rapidities are derived for repulsive and attractive correlations. In zero-field and for a repulsive interaction the spin excitations are gapped and only the charge sector has a Fermi surface. The properties are then those of a one-component Luttinger liquid. The spin-gaps are gradually closed with increasing magnetic field. For an attractive interaction potential charge bound states (generalized non-local Cooper pairs) are formed and the spin excitations are gapped in zero magnetic field. The ground state properties and the critical exponents of correlation functions are discussed for both, repulsive and attractive, potentials. The string hypothesis is invoked to derive the thermodynamic Bethe Ansatz equations. Some special limits of the thermodynamic equations are analyzed, e.g., the weak and strong interaction cases, and the low and high temperature limits.

  13. Slit-Dependent Endocytic Trafficking of the Robo Receptor Is Required for Son of Sevenless Recruitment and Midline Axon Repulsion.

    Science.gov (United States)

    Chance, Rebecca K; Bashaw, Greg J

    2015-09-01

    Understanding how axon guidance receptors are activated by their extracellular ligands to regulate growth cone motility is critical to learning how proper wiring is established during development. Roundabout (Robo) is one such guidance receptor that mediates repulsion from its ligand Slit in both invertebrates and vertebrates. Here we show that endocytic trafficking of the Robo receptor in response to Slit-binding is necessary for its repulsive signaling output. Dose-dependent genetic interactions and in vitro Robo activation assays support a role for Clathrin-dependent endocytosis, and entry into both the early and late endosomes as positive regulators of Slit-Robo signaling. We identify two conserved motifs in Robo's cytoplasmic domain that are required for its Clathrin-dependent endocytosis and activation in vitro; gain of function and genetic rescue experiments provide strong evidence that these trafficking events are required for Robo repulsive guidance activity in vivo. Our data support a model in which Robo's ligand-dependent internalization from the cell surface to the late endosome is essential for receptor activation and proper repulsive guidance at the midline by allowing recruitment of the downstream effector Son of Sevenless in a spatially constrained endocytic trafficking compartment.

  14. Bipolar outflows as a repulsive gravitational phenomenon——Azimuthally Symmetric Theory of Gravitation(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    Golden Gadzirayi Nyambuya

    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⊙,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⊙,albeit via the disk.Along the equatorial plane,the net force(with the radiation force included)on any material there-on right up to the

  15. Separation of peptides and intact proteins by electrostatic repulsion reversed phase liquid chromatography.

    Science.gov (United States)

    Gritti, Fabrice; Guiochon, Georges

    2014-12-29

    A new brand of BEH-C18 hybrid particles chemically bonded to a leash carrying an amine group permits the implementation of electrostatic repulsive interactions chromatography. Using columns packed with this material, the influence of the concentration of positive charges bonded to the BEH-C18 surface on the overloaded band profiles of a few positively charged peptides and proteins was investigated in the gradient elution mode. Three columns packed with endcapped BEH-C18 particles bonded with three different surface-charge densities (LOW, MEDIUM and HIGH) were used and compared with those provided by a column packed with non-doped, endcapped BEH-C18 particles. The surface concentrations of fixed charges in the LOW, MEDIUM and HIGH columns were estimated at 0.029, 0.050, and 0.064μmol/m(2), for example, about two orders of magnitude smaller than the surface density of bonded C18 chains (2.1μmol/m(2)). Three different mobile phase additives (0.1% v/v of trifluoro-acetic, phosphoric, and formic acid) were used to optimize the purification levels of proteins under different loading conditions. The weak ion-pairing ions (formate and phosphate) generate smaller retention but broader, more fronting band profiles than those eluted with a stronger ion-pairing ion (trifluoroactate). This effect is worse in the presence of fixed charges at the surface of the BEH-C18 particles. This was explained by an enhanced anti-Langmuirian adsorption behavior of the charged proteins in the presence of fixed surface charges. As the protein concentration increases in the bulk, so does the internal ionic strength, the electrostatic repulsive interactions weaken, and retention increases. Band fronting is mostly eliminated by replacing weak ion-pairing acids with TFA with which the adsorption isotherm remains weakly langmuirian. Faster but still complete gradient separation of insulin and myoglobin were achieved with the HIGH column than with the reference neutral column, despite a measurable

  16. Effect of repulsive interactions on the rate of doublet formation of colloidal nanoparticles in the presence of convective transport.

    Science.gov (United States)

    Lattuada, Marco; Morbidelli, Massimo

    2011-03-01

    In this work, we have performed a systematic investigation of the effect of electrostatic repulsive interactions on the aggregation rate of colloidal nanoparticles to from doublets in the presence of a convective transport mechanism. The aggregation rate has been computed by solving numerically the Fuchs-Smoluchowski diffusion-convection equation. Two convective transport mechanisms have been considered: extensional flow field and gravity-induced relative sedimentation. A broad range of conditions commonly encountered in the applications of colloidal dispersions has been analyzed. The relative importance of convective to diffusive contributions has been quantified by using the Peclet number Pe. The simulation results indicate that, in the presence of repulsive interactions, the evolution of the aggregation rate as a function of Pe can always be divided into three distinct regimes, no matter which convective mechanism is considered. At low Pe values the rate of aggregation is independent of convection and is dominated by repulsive interactions. At high Pe values, the rate of aggregation is dominated by convection, and independent of repulsive interactions. At intermediate Pe values, a sharp transition between these two regimes occurs. During this transition, which occurs usually over a 10-100-fold increase in Pe values, the aggregation rate can change by several orders of magnitude. The interval of Pe values where this transition occurs depends upon the nature of the convective transport mechanism, as well as on the height and characteristic lengthscale of the repulsive barrier. A simplified model has been proposed that is capable of quantitatively accounting for the simulations results. The obtained results reveal unexpected features of the effect of ionic strength and particle size on the stability of colloidal suspensions under shear or sedimentation, which have relevant consequences in industrial applications.

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

    Science.gov (United States)

    Ogloblya, O. V.; Kuznietsova, H. M.; Strzhemechny, Y. M.

    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.

  18. 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.

  19. Forecast and Analysis of the Main Indicators for the Development of Ocean Fishery in China during the Twelfth Five-Year Plan Period

    Institute of Scientific and Technical Information of China (English)

    Xianghong; LIN; Zhankun; WANG; Weiling; SONG; Congchun; XU

    2013-01-01

    The ocean fishery is an important part of the marine economy and an important source of human food.The leaders at all levels attach great importance to the development and utilization of ocean fishery resources.Using the regression analysis method,we forecast the main indicators for the development of ocean fishery during the Twelfth Five-Year Plan period.Through the study,it is found that in 2015,the value added of ocean fishery in China is expected to exceed 360 billion yuan,and the output of marine products will exceed 30 million tons.The marine products make stable contribution to the marine economy and the residents’nutrient composition,conducive to maintaining the stable supply of the market and meeting the residents’daily needs for marine products.

  20. 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.

  1. Topography of thalamic projections requires attractive and repulsive functions of Netrin-1 in the ventral telencephalon.

    Directory of Open Access Journals (Sweden)

    Ashton W Powell

    2008-05-01

    Full Text Available Recent studies have demonstrated that the topography of thalamocortical (TC axon projections is initiated before they reach the cortex, in the ventral telencephalon (VTel. However, at this point, the molecular mechanisms patterning the topography of TC projections in the VTel remains poorly understood. Here, we show that a long-range, high-rostral to low-caudal gradient of Netrin-1 in the VTel is required in vivo for the topographic sorting of TC axons to distinct cortical domains. We demonstrate that Netrin-1 is a chemoattractant for rostral thalamic axons but functions as a chemorepulsive cue for caudal thalamic axons. In accordance with this model, DCC is expressed in a high-rostromedial to low-caudolateral gradient in the dorsal thalamus (DTh, whereas three Unc5 receptors (Unc5A-C show graded expression in the reverse orientation. Finally, we show that DCC is required for the attraction of rostromedial thalamic axons to the Netrin-1-rich, anterior part of the VTel, whereas DCC and Unc5A/C receptors are required for the repulsion of caudolateral TC axons from the same Netrin-1-rich region of the VTel. Our results demonstrate that a long-range gradient of Netrin-1 acts as a counteracting force from ephrin-A5 to control the topography of TC projections before they enter the cortex.

  2. Pattern formation with repulsive soft-core interactions: Discrete particle dynamics and Dean-Kawasaki equation

    Science.gov (United States)

    Delfau, Jean-Baptiste; Ollivier, Hélène; López, Cristóbal; Blasius, Bernd; Hernández-García, Emilio

    2016-10-01

    Brownian particles interacting via repulsive soft-core potentials can spontaneously aggregate, despite repelling each other, and form periodic crystals of particle clusters. We study this phenomenon in low-dimensional situations (one and two dimensions) at two levels of description: by performing numerical simulations of the discrete particle dynamics and by linear and nonlinear analysis of the corresponding Dean-Kawasaki equation for the macroscopic particle density. Restricting to low dimensions and neglecting fluctuation effects, we gain analytical insight into the mechanisms of the instability leading to clustering which turn out to be the interplay among diffusion, the intracluster forces, and the forces between neighboring clusters. We show that the deterministic part of the Dean-Kawasaki equation provides a good description of the particle dynamics, including width and shape of the clusters and over a wide range of parameters, and analyze with weakly nonlinear techniques the nature of the pattern-forming bifurcation in one and two dimensions. Finally, we briefly discuss the case of attractive forces.

  3. Delocalization effect of the Hubbard repulsion in two dimensions and exact terms

    Science.gov (United States)

    Gulacsi, Zsolt

    2009-03-01

    The physical reasons explaining the delocalization effect of the Hubbard repulsion U leading in 2D to an insulator to metal transition are analyzed. The study is made in exact terms by deducing exact ground states and ground state expectation values of interest based on a positive semidefinite operator technique [1]. First it is shown that always when this effect is observed, U acts on the background of a macroscopic degeneracy present in a multiband type of system. After this step I demonstrate that acting in such conditions, by strongly diminishing the double occupancy, U spreads out the contributions in the ground state wave function, hence strongly increases the one-particle localization length, and consequently extends the one-particle behavior producing conditions for a delocalization effect [2]. [3pt] References: [1] Z. Gulacsi, D. Vollhardt, Phys. Rev. Lett. 91,186401(2003); Z. Gulacsi, A. Kampf, D. Vollhardt, Phys. Rev. Lett. 99,026404(2007). [2] Z. Gulacsi, Phys. Rev. B77,245113(2008).

  4. Chimeralike states in a network of oscillators under attractive and repulsive global coupling

    Science.gov (United States)

    Mishra, Arindam; Hens, Chittaranjan; Bose, Mridul; Roy, Prodyot K.; Dana, Syamal K.

    2015-12-01

    We report chimeralike states in an ensemble of oscillators using a type of global coupling consisting of two components: attractive and repulsive mean-field feedback. We identify the existence of two types of chimeralike states in a bistable Liénard system; in one type, both the coherent and the incoherent populations are in chaotic states (which we refer to as chaos-chaos chimeralike states) and, in another type, the incoherent population is in periodic state while the coherent population has irregular small oscillation. We find a metastable state in a parameter regime of the Liénard system where the coherent and noncoherent states migrate in time from one to another subpopulation. The relative size of the incoherent subpopulation, in the chimeralike states, remains almost stable with increasing size of the network. The generality of the coupling configuration in the origin of the chimeralike states is tested, using a second example of bistable system, the van der Pol-Duffing oscillator where the chimeralike states emerge as weakly chaotic in the coherent subpopulation and chaotic in the incoherent subpopulation. Furthermore, we apply the coupling, in a simplified form, to form a network of the chaotic Rössler system where both the noncoherent and the coherent subpopulations show chaotic dynamics.

  5. First-order phase transitions in repulsive rigid k-mers on two-dimensional lattices

    Science.gov (United States)

    Pasinetti, P. M.; Romá, F.; Ramirez-Pastor, A. J.

    2012-02-01

    In a previous paper [F. Romá, A. J. Ramirez-Pastor, and J. L. Riccardo, Phys. Rev. B 72, 035444 (2005)], the critical behavior of repulsive rigid rods of length k (k-mers) on a square lattice at half coverage has been studied by using Monte Carlo (MC) simulations. The obtained results indicated that (1) the phase transition occurring in the system is a second-order phase transition for all adsorbate sizes k; and (2) the universality class of the transition changes from 2D Ising-type for monomers (k = 1) to an unknown universality class for k ≥ 2. In the present work, we revisit our previous results together with further numerical evidences, resulting from new extensive MC simulations based on an efficient exchange algorithm and using high-performance computational capabilities. In contrast to our previous conclusions (1) and (2), the new numerical calculations clearly support the occurrence of a first-order phase transition for k ≥ 2. In addition, a similar scenario was found for k-mers adsorbed on the triangular lattice at coverage k/(2k+1).

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

    Science.gov (United States)

    Chiquillo, Emerson

    2017-03-01

    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.

  7. A review of dynamic stability of repulsive-force maglev suspension systems

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Y.; Rote, D.M.

    1998-07-01

    Vehicle dynamics and the need to satisfy ride quality requirements have long been recognized as crucial to the commercial success of passenger-carrying transportation systems. Design concepts for maglev systems are no exception. Early maglev investigators and designers were well aware of the importance of ride quality and took care to ensure that their designs would meet acceptable ride quality standards. In contrast, the dynamic stability of electrodynamic suspension (EDS) systems, which has obvious implications for system safety and cost as well as for ride quality, has not received nearly as much attention. Because of the well-known under-damped nature of EDS suspension systems and the observation of instabilities in laboratory-scale model systems, it is prudent to develop a better understanding of vehicle stability characteristics. The work reported in this was undertaken with the intention of summarizing information that has been accumulated worldwide and that is relevant to dynamic stability of repulsive-force maglev suspension systems, assimilating that information, and gaining an understanding of the factors that influence that stability. Included in the paper is a discussion and comparison of results acquired from some representative tests of large-scale vehicles on linear test tracks, together with analytical and laboratory-scale investigations of stability and dynamics of EDS systems. This paper will also summarize the R and D activities at Argonne National Laboratory (ANL) since 1991 to study the nature of the forces that are operative in an EDS system and the dynamic stability of such systems.

  8. Strong energy condition and the repulsive character of f( R) gravity

    Science.gov (United States)

    Santos, Crislane S.; Santos, Janilo; Capozziello, Salvatore; Alcaniz, Jailson S.

    2017-04-01

    The Raychaudhuri equation enables to examine the whole spacetime structure without specific solutions of Einstein's equations, playing a central role for the understanding of the gravitational interaction in cosmology. In General Relativity, without considering a cosmological constant, a non-positive contribution in the Raychaudhuri equation is usually interpreted as the manifestation of the attractive character of gravity. In this case, particular energy conditions—indeed the strong energy condition—must be assumed in order to guarantee the attractive character. In the context of f( R) gravity, however, even assuming the standard energy conditions one may have a positive contribution to the Raychaudhuri equation. Besides providing a simple way to explain the observed cosmic acceleration, this fact opens the possibility of a repulsive character of this kind of gravity. In order to discuss physical bounds on f( R) models, we address the attractive/non-attractive character of f( R) gravity considering the Raychaudhuri equation and assuming the strong energy condition along with recent estimates of the cosmographic parameters.

  9. Twisted toroidal vortex-solitons in inhomogeneous media with repulsive nonlinearity

    CERN Document Server

    Kartashov, Y V; Shnir, Y; Torner, L

    2014-01-01

    Toroidal modes in the form of so-called Hopfions, with two independent winding numbers, a hidden one (twist, s), which characterizes a circular vortex thread embedded into a three-dimensional soliton, and the vorticity around the vertical axis m, appear in many fields, including the field theory, ferromagnetics, and semi- and superconductors. Such topological states are normally generated in multi-component systems, or as trapped quasi-linear modes in toroidal potentials. We uncover that stable solitons with this structure can be created, without any linear potential, in the single-component setting with the strength of repulsive nonlinearity growing fast enough from the center to the periphery, for both steep and smooth modulation profiles. Toroidal modes with s=1 and vorticity m=0,1,2 are produced. They are stable for m1. An approximate analytical solution is obtained for the twisted ring with s=1, m=0. Under the application of an external torque, it rotates like a solid ring. The setting can be implemented...

  10. Beyond Born-Mayer: Improved models for short-range repulsion in ab initio force fields

    CERN Document Server

    Van Vleet, Mary J; Stone, Anthony J; Schmidt, J R

    2016-01-01

    Short-range repulsion within inter-molecular force fields is conventionally described by either Lennard-Jones (${A}/{r^{12}}$) or Born-Mayer ($A\\exp(-Br)$) forms. Despite their widespread use, these simple functional forms are often unable to describe the interaction energy accurately over a broad range of inter-molecular distances, thus creating challenges in the development of ab initio force fields and potentially leading to decreased accuracy and transferability. Herein, we derive a novel short-range functional form based on a simple Slater-like model of overlapping atomic densities and an iterated stockholder atom (ISA) partitioning of the molecular electron density. We demonstrate that this Slater-ISA methodology yields a more accurate, transferable, and robust description of the short-range interactions at minimal additional computational cost compared to standard Lennard-Jones or Born-Mayer approaches. Finally, we show how this methodology can be adapted to yield the standard Born-Mayer functional for...

  11. 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.

  12. 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.

  13. 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

    2015-01-01

    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. PMID:26029998

  14. Dynamical mean field theory of the repulsive BCS+U model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kwon [School of Physics, Korea Institute for Advanced Study, Seoul 130-722 (Korea, Republic of)], E-mail: kpark@kias.re.kr

    2009-07-15

    The Gutzwiller-projected BCS Hamiltonian is a useful model for high-temperature superconductivity due to its equivalence to the Heisenberg model at half filling and a close connection to the t-J model at moderate doping. In this work, a dynamical mean field theory (DMFT) is developed for the BCS Hamiltonian with d-wave pairing subject to on-site repulsive interaction, U, which we call the BCS+U model. The large-U limit corresponds to the Gutzwiller-projected BCS Hamiltonian. It is shown that the equivalence between the Heisenberg and the Gutzwiller-projected BCS model is a manifestation of a broader duality in the BCS+U model: for any finite U, the local dynamics of the BCS+U model is dual at half filling with respect to the exchange between the hopping parameter, t, and the pairing amplitude, {delta}. It is explicitly demonstrated in our DMFT analysis that the real superconducting gap, determined from the sharp coherence peaks in the local density of states, shows strong renormalization from its bare value as a function of U.

  15. An attraction-repulsion point process model for respiratory syncytial virus infections.

    Science.gov (United States)

    Goldstein, Joshua; Haran, Murali; Simeonov, Ivan; Fricks, John; Chiaromonte, Francesca

    2015-06-01

    How is the progression of a virus influenced by properties intrinsic to individual cells? We address this question by studying the susceptibility of cells infected with two strains of the human respiratory syncytial virus (RSV-A and RSV-B) in an in vitro experiment. Spatial patterns of infected cells give us insight into how local conditions influence susceptibility to the virus. We observe a complicated attraction and repulsion behavior, a tendency for infected cells to lump together or remain apart. We develop a new spatial point process model to describe this behavior. Inference on spatial point processes is difficult because the likelihood functions of these models contain intractable normalizing constants; we adapt an MCMC algorithm called double Metropolis-Hastings to overcome this computational challenge. Our methods are computationally efficient even for large point patterns consisting of over 10,000 points. We illustrate the application of our model and inferential approach to simulated data examples and fit our model to various RSV experiments. Because our model parameters are easy to interpret, we are able to draw meaningful scientific conclusions from the fitted models.

  16. A repulsion mechanism explains magnesium permeation and selectivity in CorA.

    Science.gov (United States)

    Dalmas, Olivier; Sandtner, Walter; Medovoy, David; Frezza, Ludivine; Bezanilla, Francisco; Perozo, Eduardo

    2014-02-25

    Magnesium (Mg(2+)) plays a central role in biology, regulating the activity of many enzymes and stabilizing the structure of key macromolecules. In bacteria, CorA is the primary source of Mg(2+) uptake and is self-regulated by intracellular Mg(2+). Using a gating mutant at the divalent ion binding site, we were able to characterize CorA selectivity and permeation properties to both monovalent and divalent cations under perfused two-electrode voltage clamp. The present data demonstrate that under physiological conditions, CorA is a multioccupancy Mg(2+)-selective channel, fully excluding monovalent cations, and Ca(2+), whereas in absence of Mg(2+), CorA is essentially nonselective, displaying only mild preference against other divalents (Ca(2+) > Mn(2+) > Co(2+) > Mg(2+) > Ni(2)(+)). Selectivity against monovalent cations takes place via Mg(2+) binding at a high-affinity site, formed by the Gly-Met-Asn signature sequence (Gly312 and Asn314) at the extracellular side of the pore. This mechanism is reminiscent of repulsion models proposed for Ca(2+) channel selectivity despite differences in sequence and overall structure.

  17. Three-dimensional electrospun alginate nanofiber mats via tailored charge repulsions.

    Science.gov (United States)

    Bonino, Christopher A; Efimenko, Kirill; Jeong, Sung In; Krebs, Melissa D; Alsberg, Eben; Khan, Saad A

    2012-06-25

    The formation of 3D electrospun mat structures from alginate-polyethylene oxide (PEO) solution blends is reported. These unique architectures expand the capabilities of traditional electrospun mats for applications such as regenerative medicine, where a scaffold can help to promote tissue growth in three dimensions. The mat structures extend off the surface of the flat collector plate without the need of any modifications in the electrospinning apparatus, are self-supported when the electric field is removed, and are composed of bundles of nanofibers. A mechanism for the unique formations is proposed, based on the fiber-fiber repulsions from surface charges on the negatively charged alginate. Furthermore, the role of the electric field in the distribution of alginate within the nanofibers is discussed. X-ray photoelectron spectroscopy is used to analyze the surface composition of the electrospun nanofiber mats and the data is related to cast films made in the absence of the electric field. Further techniques to tailor the 3D architecture and nanofiber morphology by changing the surface tension and relative humidity are also discussed.

  18. Two-dimensional O(3) model at nonzero density: From dual lattice simulations to repulsive bosons

    Science.gov (United States)

    Bruckmann, Falk; Gattringer, Christof; Kloiber, Thomas; Sulejmanpasic, Tin

    2016-12-01

    We discuss the thermodynamics of the O(3) nonlinear sigma model in 1 +1 dimensions at nonzero chemical potential (equivalent to a magnetic field). In its conventional field theory representation the model suffers from a sign problem. By dualizing the model, we are able to fully access the nonzero density regime of an asymptotically free theory with dynamical mass gap at arbitrary chemical potential values. We find a quantum phase transition at zero temperature where as a function of the chemical potential the density assumes a nonzero value. Measuring the spin stiffness we present evidence for a corresponding dynamical critical exponent z close to 2. The low energy O(3) model is conjectured to be described by a massive boson triplet with repulsive interactions. We confirm the universal square-root behavior expected for such a system at low density (and temperature) and compare our data to the results of Bethe Ansatz solutions of the relativistic and nonrelativistic one-dimensional Bose gas. We also comment on a potential Berezinskii-Kosterlitz-Thouless transition at nonzero density.

  19. Hyperon-mixed neutron star with universal many-body repulsion

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Y. [Institute for Physical and Chemical Research (RIKEN), Nishina Center for Accelerator-Based Science, Wako, Saitama (Japan); Furumoto, T. [Ichinoseki College, National Institute of Technology, Ichinoseki, Iwate (Japan); Yasutake, N. [Chiba Institute of Technology, Department of Physics, Chiba (Japan); Rijken, T.A. [University of Nijmegen, IMAPP, Nijmegen (Netherlands)

    2016-02-15

    Neutron stars with large masses ∝ 2M {sub CircleDot} require the hard stiffness of equation of state (EoS) of neutron-star matter. On the other hand, hyperon mixing brings about remarkable softening of EoS. In order to solve this problem, a multi-pomeron exchange potential (MPP) is introduced as a model for the universal many-body repulsion in baryonic systems on the basis of the Extended Soft Core (ESC) baryon-baryon interaction. The strength of MPP is determined by analyzing the nucleus-nucleus scattering with the G -matrix folding model. The interactions in ΛN, ΣN and ΞN channels are shown to be consistent with experimental indications. The EoS in neutron-star matter with hyperon mixing is obtained from ESC in addition of MPP, and mass-radius relations of neutron stars are derived. The maximum mass is shown to reach 2M {sub CircleDot} even in the case of including hyperon mixing on the basis of model-parameters determined by terrestrial experiments. (orig.)

  20. 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.

  1. Repulsive particles under a general external potential: Thermodynamics by neglecting thermal noise

    Science.gov (United States)

    Ribeiro, Mauricio S.; Nobre, Fernando D.

    2016-08-01

    A recent proposal of an effective temperature θ , conjugated to a generalized entropy sq, typical of nonextensive statistical mechanics, has led to a consistent thermodynamic framework in the case q =2 . The proposal was explored for repulsively interacting vortices, currently used for modeling type-II superconductors. In these systems, the variable θ presents values much higher than those of typical room temperatures T , so that the thermal noise can be neglected (T /θ ≃0 ). The whole procedure was developed for an equilibrium state obtained after a sufficiently long-time evolution, associated with a nonlinear Fokker-Planck equation and approached due to a confining external harmonic potential, ϕ (x ) =α x2/2 (α >0 ). Herein, the thermodynamic framework is extended to a quite general confining potential, namely ϕ (x ) =α|x | z/z (z >1 ). It is shown that the main results of the previous analyses hold for any z >1 : (i) The definition of the effective temperature θ conjugated to the entropy s2. (ii) The construction of a Carnot cycle, whose efficiency is shown to be η =1 -(θ2/θ1) , where θ1 and θ2 are the effective temperatures associated with two isothermal transformations, with θ1>θ2 . The special character of the Carnot cycle is indicated by analyzing another cycle that presents an efficiency depending on z . (iii) Applying Legendre transformations for a distinct pair of variables, different thermodynamic potentials are obtained, and furthermore, Maxwell relations and response functions are derived. The present approach shows a consistent thermodynamic framework, suggesting that these results should hold for a general confining potential ϕ (x ) , increasing the possibility of experimental verifications.

  2. Expression of the repulsive SLIT/ROBO pathway in the human endometrium and Fallopian tube.

    Science.gov (United States)

    Duncan, W C; McDonald, S E; Dickinson, R E; Shaw, J L V; Lourenco, P C; Wheelhouse, N; Lee, K-F; Critchley, H O D; Horne, A W

    2010-12-01

    We investigated whether the repulsive SLIT/ROBO pathway is expressed in the endometrium and is negatively regulated during implantation. We also examined whether deficient expression in the Fallopian tube (FT) may predispose to ectopic pregnancy (EP). Endometrium (n = 21) and FT (n = 17) were collected across the menstrual cycle from fertile women with regular cycles. Decidualized endometrium (n = 6) was obtained from women undergoing termination, and FT (n = 6) was obtained from women with EP. SLIT/ROBO expression was quantified by reverse transcription-PCR and protein localized by immunohistochemistry. The regulation of SLIT/ROBO expression in vitro, by sex steroids and hCG, was assessed in endometrial (hTERT-EEpC) epithelial cells, and the effects of Chlamydia trachomatis infection and smoking were studied in oviductal (OE-E6/E7) epithelial cells. Endometrial SLIT3 was highest in the mid-secretory phase (P = 0.0003) and SLIT1,2 and ROBO1 showed a similar trend. ROBO2 was highest in proliferative phase (P = 0.027) and ROBO3,4 showed a similar trend. SLIT2,3 and ROBO1, 4 were lower in decidua compared with mid-secretory endometrium (P ROBOs, excepting ROBO2, were expressed in FT but there were no differences across the cycle or in EP. SLIT/ROBO proteins were localized to endometrial and FT epithelium. Treatment of hTERT-EEpC with a combination of estradiol and medroxyprogesterone acetate inhibited ROBO1 expression (P ROBO interaction during normal development and pregnancy but that it may not be important in the aetiology of EP.

  3. Performing Hong-Ou-Mandel-type numerical experiments with repulsive condensates: The case of dark and dark-bright solitons

    Science.gov (United States)

    Sun, Zhi-Yuan; Kevrekidis, Panayotis G.; Krüger, Peter

    2016-12-01

    The Hong-Ou-Mandel experiment leads indistinguishable photons simultaneously reaching a 50:50 beam splitter to emerge on the same port through a two-photon interference. Motivated by this phenomenon, we consider numerical experiments of the same flavor for classical wave objects in the setting of repulsive condensates. We examine dark solitons interacting with a repulsive barrier, a case in which we find no significant asymmetries in the emerging waves after the collision, presumably due to their topological nature. We also consider case examples of two-component systems, where the dark solitons trap a bright structure in the second component (dark-bright solitary waves). For these, pronounced asymmetries upon collision are possible for the nontopological bright component. We also show an example of a similar phenomenology for ring dark-bright structures in two dimensions.

  4. Efimov Superchemistry:Quantum Dynamical Theory for Coherent Atom-Trimer Conversion in a Repulsive Atomic Bose-Einstein Condensate

    Institute of Scientific and Technical Information of China (English)

    JING Hui; GENG Zhen-Duo

    2008-01-01

    @@ We show that by making a generalized atom-molecule dark state,coherent creation of triatomic molecules can be enhanced in a repulsive atomic Bose-Einstein condensate.The dynamics of heteronuclear trimer creation is significantJy different from the homonuclear case and further enhancement can be realized by controlling its chemical reaction channels,The possibility of manipulating atom-trimer conversion provides an appealing research area for current coherent matter-wave optics.

  5. RESEARCH NOTE WCA repulsive and attractive contributions to the thermodynamic properties at the vapour-liquid equilibrium

    Science.gov (United States)

    Cuadros, F.; Mulero, A.; Faundez, C. A.

    The Lennard-Jones attractive and repulsive contributions of intermolecular forces (as separated in the Weeks-Chandler-Andersen (WCA) theory) to the pressure and chemical potential of coexisting vapour and liquid phases are obtained by using an equation of state recently proposed by us. Some comments are given about the computer simulation results obtained by Plackov and Sadus (1997, Fluid Phase Equilib., 134, 77) using the McQuarrie-Katz separation of the intermolecular potential.

  6. Antagonistic effects of nearest-neighbor repulsion on the superconducting pairing dynamics in the doped Mott insulator regime

    Science.gov (United States)

    Reymbaut, A.; Charlebois, M.; Asiani, M. Fellous; Fratino, L.; Sémon, P.; Sordi, G.; Tremblay, A.-M. S.

    2016-10-01

    The nearest-neighbor superexchange-mediated mechanism for dx2-y2 superconductivity in the one-band Hubbard model faces the challenge that nearest-neighbor Coulomb repulsion can be larger than superexchange. To answer this question, we use cellular dynamical mean-field theory (CDMFT) with a continuous-time quantum Monte Carlo solver to determine the superconducting phase diagram as a function of temperature and doping for on-site repulsion U =9 t and nearest-neighbor repulsion V =0 ,2 t ,4 t . In the underdoped regime, V increases the CDMFT superconducting transition temperature Tcd even though it decreases the superconducting order parameter at low temperature for all dopings. However, in the overdoped regime V decreases Tcd. We gain insight into these paradoxical results through a detailed study of the frequency dependence of the anomalous spectral function, extracted at finite temperature via the MaxEntAux method for analytic continuation. A systematic study of dynamical positive and negative contributions to pairing reveals that even though V has a high-frequency depairing contribution, it also has a low frequency pairing contribution since it can reinforce superexchange through J =4 t2/(U -V ) . Retardation is thus crucial to understanding pairing in doped Mott insulators, as suggested by previous zero-temperature studies. We also comment on the tendency to charge order for large V and on the persistence of d -wave superconductivity over extended-s or s +d wave.

  7. Operating characteristics of superconducting fault current limiter using 24kV vacuum interrupter driven by electromagnetic repulsion switch

    Energy Technology Data Exchange (ETDEWEB)

    Endo, M; Hori, T; Koyama, K; Kaiho, K; Yanabu, S [Tokyo Denki University, 2-2 Kandanishiki-chou Chiyoda-ku Tokyo 101-8457 (Japan); Yamaguchi, I; Arai, K [National Institute of Advanced Industrial Science and Technology(AIST), 1-1-1 Umezono, Tsukuba-shi, Ibaraki 305-8565 (Japan)], E-mail: yanabu@e.dendai.ac.jp

    2008-02-01

    Using a high temperature superconductor, we constructed and tested a model Superconducting Fault Current Limiter (SFCL). SFCL which has a vacuum interrupter with electromagnetic repulsion mechanism. We set out to construct high voltage class SFCL. We produced the electromagnetic repulsion switch equipped with a 24kV vacuum interrupter(VI). There are problems that opening speed becomes late. Because the larger vacuum interrupter the heavier weight of its contact. For this reason, the current which flows in a superconductor may be unable to be interrupted within a half cycles of current. In order to solve this problem, it is necessary to change the design of the coil connected in parallel and to strengthen the electromagnetic repulsion force at the time of opening the vacuum interrupter. Then, the design of the coil was changed, and in order to examine whether the problem is solvable, the current limiting test was conducted. We examined current limiting test using 4 series and 2 parallel-connected YBCO thin films. We used 12-centimeter-long YBCO thin film. The parallel resistance (0.1{omega}) is connected with each YBCO thin film. As a result, we succeed in interrupting the current of superconductor within a half cycle of it. Furthermore, series and parallel-connected YBCO thin film could limit without failure.

  8. Measurement of repulsive force of high Tc materials due to Meissner effect and its two dimensional distribution

    Science.gov (United States)

    Ishigaki, H.; Itoh, M.; Hida, A.; Endo, H.; Oya, T.

    1991-03-01

    As a basic study for magnetic bearings using high-Tc superconductors, evaluations of the materials were conducted. These evaluations included measurements of the repulsive force and lateral restoring force of various kinds of YBCO pellets. Pure air, which was supplied in the process of fabrication, and the presence of Ag in YBCO showed evidence of the effects of increasing the repulsive force. The lateral restoring force which was observed in the lateral displacement of a levitated permanent magnet over YBCO pellets was also affected by pure air and the presence of Ag. A new measuring instrument for magnetic fields was developed by using a highly sensitive force sensor. Because this instrument has the capability of measuring the repulsive force due to the Meissner effect, it was used for evaluating the two-dimensional distribution of superconducting properties. Results show that the pellets had nonuniform superconducting properties. The two-dimensional distribution of residual flux density on the pellets which had been cooled in a magnetic field (field cooling) was also observed by means of the instrument. The mechanism for generating lateral force is discussed in relation to the distribution.

  9. Pedal Power Goes Global. Twelfth Grade Economics Lesson Plan. Schools of California Online Resources for Education (SCORE): Connecting California's Classrooms to the World.

    Science.gov (United States)

    Antillas, Madeline

    Many factors must be considered when a company decides to market its product in another country. It must research the targeted country to determine if there is a demand for the product, decide on product modifications needed to match the new market, and develop a plan to market and distribute the product in this new business environment. In this…

  10. 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

  11. 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

  12. 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.

  13. 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

  14. The screened pseudo-charge repulsive potential in perturbed orbitals for band calculations by DFT+U.

    Science.gov (United States)

    Huang, Bolong

    2017-03-06

    The conventional linear response overestimates the U in DFT+U calculations for solids with fully occupied orbitals. Here, we demonstrate that the challenge arises from the incomplete cancellation of the electron-electron Coulomb repulsion energy under external perturbation. We applied the second charge response, denoted as the "pseudo-charge" model, to offset such residue effects. Counteracting between these two charge response-induced Coulomb potentials, the U parameters are self-consistently obtained by fulfilling the conditions for minimizing the non-Koopmans energy. Moreover, the pseudo-charge-induced repulsive potential shows a screening behavior related to the orbital occupation and is potentially in compliance with the screened exact exchange-correlation of electrons. The resultant U parameters are self-consistent solutions for improved band structure calculations by the DFT+U method. This work extends the validity of the linear response method to both partially and fully occupied orbitals and gives a reference for estimating the Hubbard U parameter prior to other advanced methods. The U parameters were determined in a transferability test using both PBE and hybrid density functional methods, and the results showed that this method is independent of the functional. The electronic structures determined from the hybrid-DFT+U(hybrid) approach are provided. Comparisons are also made with the recently developed self-consistent hybrid-DFT+Uw method.

  15. Dynamics of 2+1 dimensional SOS surfaces above a wall: slow mixing induced by entropic repulsion

    CERN Document Server

    Caputo, Pietro; Martinelli, Fabio; Sly, Allan; Toninelli, Fabio Lucio

    2012-01-01

    We study the Glauber dynamics for the (2+1)D Solid-On-Solid model above a hard wall and below a far away ceiling, on an $L \\times L$ box of $Z^2$ with zero boundary conditions, at large inverse-temperature $\\beta$. It was shown by Bricmont, El-Mellouki and Fr\\"ohlich (1986) that the floor constraint induces an entropic repulsion effect which lifts the surface to an average height $H \\asymp (1/\\beta)\\log L$. As an essential step in understanding the effect of entropic repulsion on the Glauber dynamics we determine the equilibrium height $H$ to within an additive constant: $H=(1/4\\beta)\\log L+O(1)$. We then show that starting from zero initial conditions the surface rises to its final height $H$ through a sequence of metastable transitions between consecutive levels. The time for a transition from height $h=aH $, $a\\in (0,1)$, to height $h+1$ is roughly $\\exp(c L^a)$ for some constant $c>0$. In particular, the mixing time of the dynamics is exponentially large in $L$, i.e., $T_{mix} \\geq e^{c L}$. We also provi...

  16. Exploring the consequences of attractive and repulsive interaction regimes in tapping mode atomic force microscopy of DNA

    Science.gov (United States)

    Round, Andrew N.; Miles, Mervyn J.

    2004-04-01

    Tapping mode atomic force microscopy (TM-AFM) in an ambient environment is a widely employed tool in the field of characterization of materials at the nanoscale. Significant advances have recently been made in the understanding of the physics behind some of the complexities of its operation, the most profound being the prediction and demonstration of the existence of the attractive and repulsive regimes of tip-sample interaction. In this paper we present an investigation of the criteria required for accessing the two imaging regimes, a simple method for controlling the transition between them in situ, and an assessment of their consequences for topographic and phase shift images of DNA. We find that the transition from repulsive to attractive regime imaging is characterized by a large increase in topographic height and concomitant decrease and sign inversion of the phase shift recorded over single molecules of DNA on mica. By varying the frequency at which the cantilever is driven, we can select which regime we wish to operate in routinely and reproducibly. Controlling the tip-sample interaction in this way greatly improves images of fragile nanoscale structures such as single molecules.

  17. Repulsive interactions induced by specific adsorption: Anomalous step diffusivity and inadequacy of nearest-neighbor Ising model. (part I experimental)

    Science.gov (United States)

    Al-Shakran, Mohammad; Kibler, Ludwig A.; Jacob, Timo; Ibach, Harald; Beltramo, Guillermo L.; Giesen, Margret

    2016-09-01

    This is Part I of two closely related papers, where we show that the specific adsorption of anions leads to a failure of the nearest-neighbor Ising model to describe island perimeter curvatures on Au(100) electrodes in dilute KBr, HCl and H2SO4 electrolytes and the therewith derived step diffusivity vs. step orientation. This result has major consequences for theoretical studies aiming at the understanding of growth, diffusion and degradation phenomena. Part I focuses on the experimental data. As shown theoretically in detail in Part II (doi:10.1016/j.susc.2016.03.022), a set of nearest-neighbor and next-nearest-neighbor interaction energies (ɛNN, ɛNNN) can uniquely be derived from the diffusivity of steps along and . We find strong repulsive next-nearest neighbor (NNN) interaction in KBr and HCl, whereas NNN interaction is negligibly for H2SO4. The NNN repulsive interaction energy ɛNNN therefore correlates positively with the Gibbs adsorption energy of the anions. We find furthermore that ɛNNN increases with increasing Br- and Cl- coverage. The results for ɛNN and ɛNNN are quantitatively consistent with the coverage dependence of the step line tension. We thereby establish a sound experimental base for theoretical studies on the energetics of steps in the presence of specific adsorption.

  18. Star polymers: study of fluid-fluid transitions in a system with a repulsive ultrasoft-core

    CERN Document Server

    Verso, F L; Reatto, L

    2003-01-01

    We study a model for star polymers in solution which, in addition to the ultrasoft repulsive interaction of entropic origin, has an attractive interpolymer interaction at longer range. This attraction can arise from a suitable tuning of the solvent and solute properties. For this model we study the phase diagram using mean-field theory and two fluid-state theories, the modified hypernetted chain (MHNC) integral equation and the hierarchical reference theory, and we explore star polymers with a different number of arms f (f = 12, 24, 32, 40). All three theories give the same topology for the phase diagram in the presence of attraction. When the strength of the interaction is strong enough a fluid-fluid phase transition appears but the coexistence curve in the density-temperature (strength of attraction) bifurcates at a triple point into two lines of coexistence terminating at two critical points. This peculiar phase behaviour is related to the unusual form of the repulsive contribution V sub r sub e sub p (r):...

  19. The Twelfth Five-Year Plan of China's dyeing and finishing industry%印染行业“十二五”发展规划

    Institute of Scientific and Technical Information of China (English)

    中国印染行业协会

    2012-01-01

    During the " Eleventh Five-Year" period, the production and marketing of China's dyeing and finishing industry kept sustained growth, structural adjustment gained substantial achievements, energy saving and emission reduction firmly pushed forward. The development model appeared to transform from quantity-oriented growth pattern to quality-oriented one. During the " Twelfth Five-Year" period, the dyeing and finishing industry should put more emphasis on technology advance, product research and development, resource saving and environment protection The industry need to promote the products' quality and added values, increase the production efficiency, reduce the production cost and the pollutant release, improve profitability and the quality and efficiency of economic growth, and speed up the transformation from quantity-oriented growth pattern to quality-oriented one%“十一五”期间,我国印染行业生产销售持续增长,经济效益稳步提高,产业结构调整取得成效,节能减排扎实推进;产业发展从数量型增长向质量效益型增长转变明显.“十二五”期间,印染行业应更加注重科技进步,注重产品研发和市场营销,注重资源节约和环境保护,提升产品质量和附加值,提高生产效率,降低生产成本,减少污染物排放,提升企业的赢利能力和水平,提高经济增长的质量和效益,推动行业由资源数量型增长向质量效益型增长转变.

  20. 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.

  1. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; Ursla Levy; John Sale; Nenad Sarunac

    2006-01-01

    This is the twelfth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, the development of analyses to determine the costs and financial benefits of coal drying was continued. The details of the model and key assumptions being used in the economic evaluation are described in this report and results are shown for a drying system utilizing a combination of waste heat from the condenser and thermal energy extracted from boiler flue gas.

  2. USE OF COAL DRYING TO REDUCE WATER CONSUMED IN PULVERIZED COAL POWER PLANTS

    Energy Technology Data Exchange (ETDEWEB)

    Edward Levy; Harun Bilirgen; Ursla Levy; John Sale; Nenad Sarunac

    2006-01-01

    This is the twelfth Quarterly Report for this project. The background and technical justification for the project are described, including potential benefits of reducing fuel moisture using power plant waste heat, prior to firing the coal in a pulverized coal boiler. During this last Quarter, the development of analyses to determine the costs and financial benefits of coal drying was continued. The details of the model and key assumptions being used in the economic evaluation are described in this report and results are shown for a drying system utilizing a combination of waste heat from the condenser and thermal energy extracted from boiler flue gas.

  3. Testing Nelder-Mead based repulsion algorithms for multiple roots of nonlinear systems via a two-level factorial design of experiments.

    Directory of Open Access Journals (Sweden)

    Gisela C V Ramadas

    Full Text Available This paper addresses the challenging task of computing multiple roots of a system of nonlinear equations. A repulsion algorithm that invokes the Nelder-Mead (N-M local search method and uses a penalty-type merit function based on the error function, known as 'erf', is presented. In the N-M algorithm context, different strategies are proposed to enhance the quality of the solutions and improve the overall efficiency. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm.

  4. Testing Nelder-Mead based repulsion algorithms for multiple roots of nonlinear systems via a two-level factorial design of experiments.

    Science.gov (United States)

    Ramadas, Gisela C V; Rocha, Ana Maria A C; Fernandes, Edite M G P

    2015-01-01

    This paper addresses the challenging task of computing multiple roots of a system of nonlinear equations. A repulsion algorithm that invokes the Nelder-Mead (N-M) local search method and uses a penalty-type merit function based on the error function, known as 'erf', is presented. In the N-M algorithm context, different strategies are proposed to enhance the quality of the solutions and improve the overall efficiency. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm. The main goal of this paper is to use a two-level factorial design of experiments to analyze the statistical significance of the observed differences in selected performance criteria produced when testing different strategies in the N-M based repulsion algorithm.

  5. Dusty plasma microparticle cloud control and rapid electrostatic mutual-repulsion expansion in a DC glow discharge

    Science.gov (United States)

    Gillman, Eric; Amatucci, Bill

    2016-10-01

    Microparticles in plasma discharges rapidly charge up, typically collecting a net negative charge due to the relatively high mobility of electrons compared to ions. Electrostatic forces can be utilized to control charged microparticle behavior and motion in a plasma discharge. In these experiments a metal wire loop is supplied with an electric potential that can be controlled independently from the DC plasma glow discharge electrodes. By varying the voltage on the wire loop, we can attract, trap, manipulate, suspend, and/or repel microparticles that originate from the DC glow discharge. Experiments studied the properties of electrostatic self-repulsion of a cloud of charged microparticles. By pulsing the plasma and controlling wire loop potential, a cloud of trapped microparticles is released and allowed to rapidly expand. A simple force balance simulation code is used as a model to compare and benchmark actual experimental results. This work was supported by the Naval Research Laboratory base program.

  6. Cap mesenchyme cell swarming during kidney development is influenced by attraction, repulsion, and adhesion to the ureteric tip.

    Science.gov (United States)

    Combes, Alexander N; Lefevre, James G; Wilson, Sean; Hamilton, Nicholas A; Little, Melissa H

    2016-10-15

    Morphogenesis of the mammalian kidney requires reciprocal interactions between two cellular domains at the periphery of the developing organ: the tips of the epithelial ureteric tree and adjacent regions of cap mesenchyme. While the presence of the cap mesenchyme is essential for ureteric branching, how it is specifically maintained at the tips is unclear. Using ex vivo timelapse imaging we show that cells of the cap mesenchyme are highly motile. Individual cap mesenchyme cells move within and between cap domains. They also attach and detach from the ureteric tip across time. Timelapse tracks collected for >800 cells showed evidence that this movement was largely stochastic, with cell autonomous migration influenced by opposing attractive, repulsive and cell adhesion cues. The resulting swarming behaviour maintains a distinct cap mesenchyme domain while facilitating dynamic remodelling in response to underlying changes in the tip. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Dual function of Slit2 in repulsion and enhanced migration of trunk, but not vagal, neural crest cells.

    Science.gov (United States)

    De Bellard, Maria Elena; Rao, Yi; Bronner-Fraser, Marianne

    2003-07-21

    Neural crest precursors to the autonomic nervous system form different derivatives depending upon their axial level of origin; for example, vagal, but not trunk, neural crest cells form the enteric ganglia of the gut. Here, we show that Slit2 is expressed at the entrance of the gut, which is selectively invaded by vagal, but not trunk, neural crest. Accordingly, only trunk neural crest cells express Robo receptors. In vivo and in vitro experiments demonstrate that trunk, not vagal, crest cells avoid cells or cell membranes expressing Slit2, thereby contributing to the differential ability of neural crest populations to invade and innervate the gut. Conversely, exposure to soluble Slit2 significantly increases the distance traversed by trunk neural crest cells. These results suggest that Slit2 can act bifunctionally, both repulsing and stimulating the motility of trunk neural crest cells.

  8. Traveling plateaus for a hyperbolic Keller-Segel system with attraction and repulsion: existence and branching instabilities

    CERN Document Server

    Perthame, Benoit; Tang, Min; Vauchelet, Nicolas

    2010-01-01

    How can repulsive and attractive forces, acting on a conservative system, create stable traveling 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 modeling work, where we have shown numerically that branching patterns arise for this system and we have analyzed 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 analyze steady states. Secondly we analyze traveling waves when neglecting the degradation coefficient of the chemo-repellent; the unique wave speed appears thr...

  9. 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.

  10. Comparison of repulsive interatomic potentials calculated with an all-electron DFT approach with experimental data

    Science.gov (United States)

    Zinoviev, A. N.; Nordlund, K.

    2017-09-01

    The interatomic potential determines the nuclear stopping power in materials. Most ion irradiation simulation models are based on the universal Ziegler-Biersack-Littmark (ZBL) potential (Ziegler et al., 1983), which, however, is an average and hence may not describe the stopping of all ion-material combinations well. Here we consider pair-specific interatomic potentials determined experimentally and by density-functional theory simulations with DMol approach (DMol software, 1997) to choose basic wave functions. The interatomic potentials calculated using the DMol approach demonstrate an unexpectedly good agreement with experimental data. Differences are mainly observed for heavy atom systems, which suggests they can be improved by extending a basis set and more accurately considering the relativistic effects. Experimental data prove that the approach of determining interatomic potentials from quasielastic scattering can be successfully used for modeling collision cascades in ion-solids collisions. The data obtained clearly indicate that the use of any universal potential is limited to internuclear distances R < 7 af (af is the Firsov length).

  11. 荆州市基础测绘“十二五”规划编制研究%The Twelfth Five-Year Planning Research of the Basic Surveying and Mapping in Jingzhou

    Institute of Scientific and Technical Information of China (English)

    周勇; 胡冰; 彭李; 石莎

    2012-01-01

    基础测绘是国民经济和社会发展的一项长期的基础性工作。分析了荆州市基础测绘“十一五”期间取得的成绩和存在的问题,阐述了“十二五”期间经济社会发展对基础测绘的需求,提出了基础测绘的发展目标,明确了基础测绘的6项任务,制定了基础测绘重点项目规划,为地市级基础测绘“十二五”规划编制提供思路。%Basic surveying and mapping is a long-term basic and strategic work of the economic and social develop- ment. The paper analyzes the achievements and existing problems of Jingzhou basic surveying and mapping during the E- leventh Five-Year Plan period, describes the needs of economic and social development during the Twelfth Five-year Plan period. It proposes development goals of basic surveying and mapping, defines its six tasks and formulates key pro- jects plan. Ideas for establishing city basic surveying and mapping during the Twelfth Five-Year Plan are presented.

  12. 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.

  13. Research on Affordable Housing Construction of Shanxi Province during the Twelfth Five-year Plan%山西省城镇"十二五"经济适用房研究

    Institute of Scientific and Technical Information of China (English)

    范恩海; 郑婷兰

    2011-01-01

    经济适用房是我国住房保障体系的重要组成部分,"十二五"期间应该加大经济适用房建设力度,以满足城镇中(低)收入家庭的基本住房需求.借助以及市场调查等统计资料,通过分析山西省商品住房市场价格、城镇新增居民家庭人均可支配收入等情况,预测得到经济适用房的保障线标准和保障比例,从而确定出"十二五"期间新增经济适用房的建设数量.%Affordable housing is an important part of China's housing security system. We should intensify affordable housing construction during the twelfth five-year to meet the basic housing demand of low-and middle-income families. With the help of statistical date which quoted from The Clorious 60 Years of Shanxi and market research statistical data through the analysis of the commodity housing market prices and per capita disposable income of urban increased households in Shanxi Province, predicts the security standards and security proportion of affordable housing, so as to determine the increased construction quantity of affordable housing during the twelfth five-year.

  14. 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

  15. 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

  16. Multicritical phase diagrams of the Blume-Emery-Griffiths model with repulsive biquadratic coupling including metastable phases

    Science.gov (United States)

    Ekiz, Cesur; Keskin, Mustafa

    2002-08-01

    We investigate the thermal variations of the spin-1 Blume-Emergy-Griffiths model with the repulsive biquadratic interaction by using the lowest approximation of the cluster-variation method. Besides the stable branches of the order parameters, we obtain the metastable and unstable parts of these curves and also find phase transitions of the metastable branches of the order parameters. 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 the path probability method in order to make sure that we find and define the metastable and unstable branches of the order parameters completely and correctly. This is done by studying the relaxation of the order parameters and as well as expressing the solution of the dynamic equations by means of the flow diagrams. Finally, we present the metastable phase diagrams in addition to the equilibrium phase diagrams in (kT/J,D/J) and (kT/J,K/J) planes.

  17. 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.

  18. 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.

  19. 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.

  20. Impurity in a Bose-Einstein condensate: Study of the attractive and repulsive branch using quantum Monte Carlo methods

    Science.gov (United States)

    Ardila, L. A. Peña; Giorgini, S.

    2015-09-01

    We investigate the properties of an impurity immersed in a dilute Bose gas at zero temperature using quantum Monte Carlo methods. The interactions between bosons are modeled by a hard-sphere potential with scattering length a , whereas the interactions between the impurity and the bosons are modeled by a short-range, square-well potential where both the sign and the strength of the scattering length b can be varied by adjusting the well depth. We characterize the attractive and the repulsive polaron branch by calculating the binding energy and the effective mass of the impurity. Furthermore, we investigate the structural properties of the bath, such as the impurity-boson contact parameter and the change of the density profile around the impurity. At the unitary limit of the impurity-boson interaction, we find that the effective mass of the impurity remains smaller than twice its bare mass, while the binding energy scales with ℏ2n2 /3/m , where n is the density of the bath and m is the common mass of the impurity and the bosons in the bath. The implications for the phase diagram of binary Bose-Bose mixtures at low concentrations are also discussed.

  1. Fluctuations in an ordered c (2×2) two-dimensional lattice-gas system with repulsive interactions

    Science.gov (United States)

    Argyrakis, P.; Chumak, A. A.; Maragakis, M.

    2005-06-01

    Fluctuations of the particle density in an ordered c(2×2) two-dimensional lattice-gas system are studied both analytically and by means of Monte Carlo simulations. The ordering is caused by a strong interparticle repulsive interaction resulting in the second order phase transition. The lattice of adsorption sites is divided into two sublattices (almost filled and almost empty sublattices) each of which contains a small number of structural “defects,” i.e., vacancies and excess particles. The relaxation of the correlation function of fluctuations turns out to be governed by two different functions. This peculiarity is to be contrasted with the traditional fluctuation theory which predicts the existence of a single damping constant, determined by the collective diffusion coefficient. A specific thesis of the proposed approach is that transport phenomena in ordered systems may be described in terms of both displacements and generation-recombination of structural defects. Accordingly, the correlation function of fluctuations depends on diffusion coefficients of two defect species as well as on the generation-recombination frequency. Our theory reduces to the usual one when fluctuations occur under local equilibrium conditions, i.e., for a sufficiently large size of probe areas and not too great values of interaction parameter. The analytical results agree well with those obtained in the Monte Carlo framework.

  2. Motor neuron cell bodies are actively positioned by Slit/Robo repulsion and Netrin/DCC attraction.

    Science.gov (United States)

    Kim, Minkyung; Fontelonga, Tatiana; Roesener, Andrew P; Lee, Haeram; Gurung, Suman; Mendonca, Philipe R F; Mastick, Grant S

    2015-03-01

    Motor neurons differentiate from a ventral column of progenitors and settle in static clusters, the motor nuclei, next to the floor plate. Within these cell clusters, motor neurons receive afferent input and project their axons out to muscle targets. The molecular mechanisms that position motor neurons in the neural tube remain poorly understood. The floor plate produces several types of guidance cues with well-known roles in attracting and repelling axons, including the Slit family of chemorepellents via their Robo receptors, and Netrin1 via its DCC attractive receptor. In the present study we found that Islet1(+) motor neuron cell bodies invaded the floor plate of Robo1/2 double mutant mouse embryos or Slit1/2/3 triple mutants. Misplaced neurons were born in their normal progenitor column, but then migrated tangentially into the ventral midline. Robo1 and 2 receptor expression in motor neurons was confirmed by reporter gene staining and anti-Robo antibody labeling. Mis-positioned motor neurons projected their axons longitudinally within the floor plate, and failed to reach their normal exit points. To test for potential counteracting ventral attractive signals, we examined Netrin-1 and DCC mutants, and found that motor neurons shifted dorsally in the hindbrain and spinal cord, suggesting that Netrin-1/DCC signaling normally attracts motor neurons closer to the floor plate. Our results show that motor neurons are actively migrating cells, and are normally trapped in a static position by Slit/Robo repulsion and Netrin-1/DCC attraction.

  3. Developmental guidance of the retroflex tract at its bending point involves Robo1-Slit2-mediated floor plate repulsion.

    Science.gov (United States)

    Moreno-Bravo, Juan A; Martinez-Lopez, Jesus E; Madrigal, M Pilar; Kim, Minkyung; Mastick, Grant S; Lopez-Bendito, Guillermina; Martinez, Salvador; Puelles, Eduardo

    2016-01-01

    The retroflex tract contains medial habenula efferents that target the hindbrain interpeduncular complex and surrounding areas. This tract displays a singular course. Initially, habenular axons extend ventralwards in front of the pretectum until they reach the basal plate. Next, they avoid crossing the local floor plate, sharply changing course caudalwards (the retroflexion alluded by the tract name) and navigate strictly antero-posteriorly across basal pretectum, midbrain and isthmus. Once they reach rhombomere 1, the habenular axons criss-cross the floor plate several times within the interpeduncular nuclear complex as they innervate it. Here we described the timing and details of growth phenomena as these axons navigate to their target. The first dorsoventral course apparently obeys Ntn1 attraction. We checked the role of local floor plate signaling in the decision to avoid the thalamic floor plate and bend caudalwards. Analyzing the altered floor and basal plates of Gli2 knockout mice, we found a contralateral projection of most habenular axons, plus ulterior bizarre navigation rostralwards. This crossing phenotype was due to a reduced expression of Slit repulsive cues, suggesting involvement of the floor-derived Robo-Slit system in the normal guidance of this tract. Using Slit and Robo mutant mice, open neural tube and co-culture assays, we determined that Robo1-Slit2 interaction is specifically required for impeding that medial habenular axons cross the thalamic floor plate. This pathfinding mechanism is essential to establish the functionally important habenulo-interpeduncular connection.

  4. Slit2 regulates attractive eosinophil and repulsive neutrophil chemotaxis through differential srGAP1 expression during lung inflammation.

    Science.gov (United States)

    Ye, Bu-Qing; Geng, Zhen H; Ma, Li; Geng, Jian-Guo

    2010-11-15

    Directional migration of leukocytes is an essential step in leukocyte trafficking during inflammatory responses. However, the molecular mechanisms governing directional chemotaxis of leukocytes remain poorly understood. The Slit family of guidance cues has been implicated for inhibition of leuocyte migration. We report that Clara cells in the bronchial epithelium secreted Slit2, whereas eosinophils and neutrophils expressed its cell-surface receptor, Robo1. Compared to neutrophils, eosinophils exhibited a significantly lower level of Slit-Robo GTPase-activating protein 1 (srGAP1), leading to activation of Cdc42, recruitment of PI3K to Robo1, enhancment of eotaxin-induced eosinophil chemotaxis, and exaggeration of allergic airway inflammation. Notably, OVA sensitization elicited a Slit2 gradient at so-called bronchus-alveoli axis, with a higher level of Slit2 in the bronchial epithelium and a lower level in the alveolar tissue. Aerosol administration of rSlit2 accelerated eosinophil infiltration, whereas i.v. administered Slit2 reduced eosinophil deposition. In contrast, Slit2 inactivated Cdc42 and suppressed stromal cell-derived factor-1α-induced chemotaxis of neutrophils for inhibiting endotoxin-induced lung inflammation, which were reversed by blockade of srGAP1 binding to Robo1. These results indicate that the newly identified Slit2 gradient at the bronchus-alveoli axis induces attractive PI3K signaling in eosinophils and repulsive srGAP1 signaling in neutrophils through differential srGAP1 expression during lung inflammation.

  5. CSP and takeout genes modulate the switch between attraction and repulsion during behavioral phase change in the migratory locust.

    Directory of Open Access Journals (Sweden)

    Wei Guo

    Full Text Available Behavioral plasticity is the most striking trait in locust phase transition. However, the genetic basis for behavioral plasticity in locusts is largely unknown. To unravel the molecular mechanisms underlying the behavioral phase change in the migratory locust Locusta migratoria, the gene expression patterns over the time courses of solitarization and gregarization were compared by oligonucleotide microarray analysis. Data analysis revealed that several gene categories relevant to peripheral olfactory perception are strongly regulated in a total of 1,444 differentially expressed genes during both time courses. Among these candidate genes, several CSP (chemosensory protein genes and one takeout gene, LmigTO1, showed higher expression in gregarious and solitarious locusts, respectively, and displayed opposite expression trends during solitarization and gregarization. qRT-PCR experiments revealed that most CSP members and LmigTO1 exhibited antenna-rich expressions. RNA interference combined with olfactory behavioral experiments confirmed that the CSP gene family and one takeout gene, LmigTO1, are involved in the shift from repulsion to attraction between individuals during gregarization and in the reverse transition during solitarization. These findings suggest that the response to locust-emitted olfactory cues regulated by CSP and takeout genes is involved in the behavioral phase change in the migratory locust and provide a previously undescribed molecular mechanism linked to the formation of locust aggregations.

  6. Femtosecond optical reflectivity measurements of lattice-mediated spin repulsions in photoexcited LaCoO3 thin films

    Science.gov (United States)

    Bielecki, J.; Rata, A. D.; Börjesson, L.

    2014-01-01

    We present results on the temperature dependence of ultrafast electron and lattice dynamics, measured with pump-probe transient reflectivity experiments, of an epitaxially grown LaCoO3 thin film under tensile strain. Probing spin-polarized transitions into the antibonding eg band provides a measure of the low-spin fraction, both as a function of temperature and time after photoexcitation. It is observed that femtosecond laser pulses destabilize the constant low-spin fraction (˜63%-64%) in equilibrium into a thermally activated state, driven by a subpicosecond change in spin gap Δ. From the time evolution of the low-spin fraction, it is possible to disentangle the thermal and lattice contributions to the spin state. A lattice mediated spin repulsion, identified as the governing factor determining the equilibrium spin state in thin-film LaCoO3, is observed. These results suggests that time-resolved spectroscopy is a sensitive probe of the spin state in LaCoO3 thin films, with the potential to bring forward quantitative insight into the complicated interplay between structure and spin state in LaCoO3.

  7. Bound states in the three-dimensional electron gas with repulsive or attractive test charges: many-body effects

    Science.gov (United States)

    Gold, A.; Ghazali, A.

    1996-09-01

    In the low-density regime bound states between negative (repulsive) test charges are obtained when many-body effects (exchange and correlation) are incorporated in the screening function of the three-dimensional electron gas via the local-field correction. The Schrödinger equation is solved in the momentum space by diagonalizing the corresponding matrix. We also perform variational calculations and find good agreement between the two methods. For high electron density 0953-8984/8/40/006/img5 (0953-8984/8/40/006/img6 is the density parameter) no bound states are found. Below a critical density 0953-8984/8/40/006/img7 the number and the energy of bound states increase with decreasing electron density. For large 0953-8984/8/40/006/img6 the binding energy for the ground state saturates near 0953-8984/8/40/006/img9. We discuss the wave functions of the ground state and of the lowest excited states. We also present results for the effects of exchange and correlation for a positive (attractive) test charge and we discuss results for the ground state and excited states.

  8. Sebaceous lipids are essential for water repulsion, protection against UVB-induced apoptosis and ocular integrity in mice.

    Science.gov (United States)

    Dahlhoff, Maik; Camera, Emanuela; Schäfer, Matthias; Emrich, Daniela; Riethmacher, Dieter; Foster, April; Paus, Ralf; Schneider, Marlon R

    2016-05-15

    Sebocytes, which are characterized by lipid accumulation that leads to cell disruption, can be found in hair follicle-associated sebaceous glands (SGs) or in free SGs such as the Meibomian glands in the eyelids. Because genetic tools that allow targeting of sebocytes while maintaining intact epidermal lipids are lacking, the relevance of sebaceous lipids in health and disease remains poorly understood. Using Scd3, which is expressed exclusively in mature sebocytes, we established a mouse line with sebocyte-specific expression of Cre recombinase. Both RT-PCR analysis and crossing into Rosa26-lacZ reporter mice and Kras(G12D) mice confirmed Cre activity specifically in SGs, with no activity in other skin compartments. Importantly, loss of SCD3 function did not cause detectable phenotypical alterations, endorsing the usefulness of Scd3-Cre mice for further functional studies. Scd3-Cre-induced, diphtheria chain A toxin-mediated depletion of sebaceous lipids resulted in impaired water repulsion and thermoregulation, increased rates of UVB-induced epidermal apoptosis and caused a severe pathology of the ocular surface resembling Meibomian gland dysfunction. This novel mouse line will be useful for further investigating the roles of sebaceous lipids in skin and eye integrity.

  9. “十二五”末江西增产“50亿斤粮”的出路与对策建议%Solutions and Countermeasures for "Increasing Grain Products by 2.5 Billion Kilogram" of Jiangxi in "Twelfth Five - years"

    Institute of Scientific and Technical Information of China (English)

    杨正威; 陈红萍; 颜龙安; 陆朝梁; 熊大建; 龙丘陵

    2012-01-01

    江西省“十二五”规划纲要中提出“十二五”期间我省“新增粮食产量50亿斤”,以策应国家“十二五”“增加1000亿斤粮食”的目标.本文分析了当前江西粮食综合生产能力及存在的问题、粮食生产中有利条件和面临的挑战,提出了“十二五”末江西增产“50亿斤粮”的出路与对策建议.%In order to support the country's target of "increasing the grain products by 50 billion kilogram" in "Twelfth Five -years" , the "Twelfth Five - years" planning program of Jiangxi province put forward "increasing the grain products by 2.5 billion kilogram" in "Twelfth Five-years". This paper analyzed the overall grain production capability, the existing problems, advantages and faced challenges in grain production of Jiangxi at present, and put forward the solutions and countermeasures for "increasing the grain products by 2.5 billion kilogram" of Jiangxi in "Twelfth Five -years".

  10. Repulsive-SVDD Classification

    Science.gov (United States)

    2015-05-22

    Switzerland 2015 T. Cao et al. (Eds.): PAKDD 2015, Part I, LNAI 9077, pp. 277–288, 2015. DOI: 10.1007/978-3-319-18038-0 22 278 P. Nguyen and D. Tran between the...P. Nguyen and D. Tran References 1. Tax, D.M.J., Duin, R.P.W.: Support vector data description. Machine Learning 54(1), 45–66 ( 2004 ) 2. Schlkopf, B

  11. “十二五”期间陕西人身保险市场需求变化研究%Analysis of the Changes in Life Insurance Market Demand of Shaanxi Province During the Twelfth Five-Year

    Institute of Scientific and Technical Information of China (English)

    杨馥; 刘珺

    2012-01-01

    The development of life insurance market in Shaanxi Province will be promoted by the substainable development of Shaanxi's economy and society during the Twelfth Five-Year.The demand of life insurance is key index of the development of lif insurance market.The demand of life insurance market is measured by life insurance premiums in Shaanxi.Based on the data in 1990-2009,this paper provides positive analysis on the demand of life insurance market in Shaanxi by cointegration and logarithm function-model.Following the results,it predicts the trends of life insurance market demands in Shanxi during the Twelfth Five-Year plan,to provide theory basis for life insurance market planning.%"十二五"期间,陕西省经济的持续发展为陕西省人身保险市场的发展提供了有利契机。人身保险需求是度量人身保险市场发展状况的重要指标。文章以陕西省人身保险保费收入作为衡量人身保险市场需求的变量,参考保险密度和保险深度等指标,选取1990—2009年的相关数据,采用协整检验,利用自然对数模型对陕西省人身保险市场需求进行实证分析,并据此对"十二五"期间陕西省人身保险市场需求变化趋势进行预测,旨在为陕西省人身保险业规划提供理论依据。

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

    Directory of Open Access Journals (Sweden)

    Emi Tamechika

    2012-10-01

    Full Text Available 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.

  13. 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.

  14. 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.

  15. 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

    2012-10-17

    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.

  16. Screened spin-1 and -1/2 Kondo effect in a triangular quantum dot system with interdot Coulomb repulsion

    Science.gov (United States)

    Xiong, Yong-Chen; Wang, Wei-Zhong; Luo, Shi-Jun; Yang, Jun-Tao; Huang, Hai-Ming

    2017-03-01

    By means of the numerical renormalization group (NRG) technique, we study the low temperature transport property and the phase transition for a triangular triple quantum dot system, including two centered dots (dot 1 and 2) and one side dot (dot 3). We focus on the effect of interdot repulsion V between two centered dots in a wide range of the interdot hopping tij (i,j = 1,2,3). When the hoppings between the centered dot and the side dot are symmetric, i.e., t13 = t23, and that between two centered dots t12 is small, two centered dots form a spin triplet when V is absent, and a totally screened spin-1 Kondo effect is observed. In this case, one has a spin 1 that is partially screened by the leads as in the usual spin-1 Kondo model, and the remaining spin 1/2 degree of freedom forms a singlet with the side dot. As V is large enough, one of the centered dots is singly occupied, while the other one is empty. The spin-1/2 Kondo effect is found when t13 is small. For large t12, two centered dots form a spin singlet when V = 0, leading to zero conductance. As V is large enough, the spin-1/2 Kondo effect is recovered in the case of small t13. For asymmetric t13≠t23 and small t12, a crossover is found as V increases in comparison with a first order quantum phase transition for the symmetric case. In the regime of large V, the spin-1/2 Kondo effect could also be found when both t13 and t23 are small. We demonstrate the present model is similar to the side-coupled double dot system in some appropriate regimes, and it appears as a possible realization of side-controllable molecular electronics and spintronics devices.

  17. Casimir-Lifshitz interaction between ZnO and SiO2 nanorods in bromobenzene: retardation effects turn the interaction repulsive at intermediate separations

    CERN Document Server

    Boström, Mathias; Baldissera, Gustavo; Persson, Clas; Ninham, Barry W

    2012-01-01

    We consider the interaction between a ZnO nanorod and a SiO2 nanorod in bromobenzene. Using optical data for the interacting objects and ambient we calculate the force - from short-range attractive van der Waals force to intermediate range repulsive Casimir-Lifshitz force to long range entropically driven attraction. The nonretarded van der Waals interaction is attractive at all separations. We demonstrate a retardation driven repulsion at intermediate separations. At short separations (in the nonretarded limit) and at large separations (in the classical limit) the interaction is attractive. These effects can be understood from an analysis of multiple crossings of the dielectric functions of the three media as functions of imaginary frequencies.

  18. Repulsive axon guidance by Draxin is mediated by protein Kinase B (Akt), glycogen synthase kinase-3β (GSK-3β) and microtubule-associated protein 1B.

    Science.gov (United States)

    Meli, Rajeshwari; Weisová, Petronela; Propst, Friedrich

    2015-01-01

    Draxin is an important axon guidance cue necessary for the formation of forebrain commissures including the corpus callosum, but the molecular details of draxin signaling are unknown. To unravel how draxin signals are propagated we used murine cortical neurons and genetic and pharmacological approaches. We found that draxin-induced growth cone collapse critically depends on draxin receptors (deleted in colorectal cancer, DCC), inhibition of protein kinase B/Akt, activation of GSK-3β (glycogen synthase kinase-3β) and the presence of microtubule-associated protein MAP1B. This study, for the first time elucidates molecular events in draxin repulsion, links draxin and DCC to MAP1B and identifies a novel MAP1B-depenent GSK-3β pathway essential for chemo-repulsive axon guidance cue signaling.

  19. Model Fitting Versus Curve Fitting: A Model of Renormalization Provides a Better Account of Age Aftereffects Than a Model of Local Repulsion.

    Science.gov (United States)

    O'Neil, Sean F; Mac, Amy; Rhodes, Gillian; Webster, Michael A

    2015-12-01

    Recently, we proposed that the aftereffects of adapting to facial age are consistent with a renormalization of the perceived age (e.g., so that after adapting to a younger or older age, all ages appear slightly older or younger, respectively). This conclusion has been challenged by arguing that the aftereffects can also be accounted for by an alternative model based on repulsion (in which facial ages above or below the adapting age are biased away from the adaptor). However, we show here that this challenge was based on allowing the fitted functions to take on values which are implausible and incompatible across the different adapting conditions. When the fits are constrained or interpreted in terms of standard assumptions about normalization and repulsion, then the two analyses both agree in pointing to a pattern of renormalization in age aftereffects.

  20. Phosphorylation of Rab-coupling protein by LMTK3 controls Rab14-dependent EphA2 trafficking to promote cell:cell repulsion.

    Science.gov (United States)

    Gundry, Christine; Marco, Sergi; Rainero, Elena; Miller, Bryan; Dornier, Emmanuel; Mitchell, Louise; Caswell, Patrick T; Campbell, Andrew D; Hogeweg, Anna; Sansom, Owen J; Morton, Jennifer P; Norman, Jim C

    2017-03-15

    The Rab GTPase effector, Rab-coupling protein (RCP) is known to promote invasive behaviour in vitro by controlling integrin and receptor tyrosine kinase (RTK) trafficking, but how RCP influences metastasis in vivo is unclear. Here we identify an RTK of the Eph family, EphA2, to be a cargo of an RCP-regulated endocytic pathway which controls cell:cell repulsion and metastasis in vivo. Phosphorylation of RCP at Ser(435) by Lemur tyrosine kinase-3 (LMTK3) and of EphA2 at Ser(897) by Akt are both necessary to promote Rab14-dependent (and Rab11-independent) trafficking of EphA2 which generates cell:cell repulsion events that drive tumour cells apart. Genetic disruption of RCP or EphA2 opposes cell:cell repulsion and metastasis in an autochthonous mouse model of pancreatic adenocarcinoma-whereas conditional knockout of another RCP cargo, α5 integrin, does not suppress pancreatic cancer metastasis-indicating a role for RCP-dependent trafficking of an Eph receptor to drive tumour dissemination in vivo.

  1. Aggregation kinetics of single-walled carbon nanotubes investigated using mechanically wrapped multinuclear complexes: probing the tube-tube repulsive barrier.

    Science.gov (United States)

    Ameen, Anjail A; Giordano, Andrea N; Alston, Jeffrey R; Forney, Michael W; Herring, Natalie P; Kobayashi, Shiho; Ridlen, Shawn G; Subaran, Sarah S; Younts, Thomas J; Poler, J C

    2014-03-28

    The rational design of supraparticle assemblies requires a detailed understanding of directed assembly processes. The stability of dispersions of nanoscale materials, like single-walled carbon nanotubes (SWCNTs), is still not fully understood, nor are the mechanisms of aggregation and assembly. A detailed balance of attractive van der Waals type interactions with various repulsive barrier mechanisms is needed to control the assembly of industrially viable and functional hybrid-nanoscale supraparticles. We report a detailed study of SWCNT dispersion stability and aggregation kinetics as a function of the nature of the coagulant used in various solvent systems. We explore three classes of coagulants that vary in charge, size, shape, solvation energy, and the ability to bind to the SWCNTs. We use these kinetic data to assess the tube-solvent-coagulant-tube interactions. We compare the relative contributions from two types of repulsive barriers. We find that tube-mediated structured solvent around the SWCNTs does not sufficiently describe our measured kinetic data. A DLVO type, electrical double layer repulsion is used to rationalize our observations. The data presented in this paper require a more detailed theoretical understanding of the physico-chemical environment near nanoparticle surfaces such as aggregating SWCNTs.

  2. In Theory: Dark Energy as a Power Source

    Science.gov (United States)

    Nemiroff, Robert J.; Russell, David; Tangmatitham, Matipon

    2017-01-01

    In theory, it is possible to use the dark energy of the universe as a power source. In practice, the amount of energy that could be liberated in a local setting is many orders of magnitude too small to be useful or even detectable. Nevertheless, in the interests of education and amusement, simple machines that could, in theory, extract local power from the gravitationally repulsive cosmological constant are discussed. The gravitational neutral buoyancy distance -- the distance where local Newtonian gravity balances cosmological dark energy in a concordance cosmology -- is computed between two point objects of low mass.

  3. The role of higher-multipolar and repulsive forces in the calculation of collision-broadened line-widths of linear molecules

    Science.gov (United States)

    Varanasi, P.; Sarangi, S.

    1974-01-01

    Collision-broadened line widths in CO-CO2 and CO-O2 collisions have been calculated by incorporating interactions due to octopoles and hexadecapoles and short-range repulsive interactions into Anderson's (1949) theory. It is shown how these higher-order interactions can be manipulated to yield good agreement with experimental data. A critical evaluation of this totally empirical manipulation suggests that a thorough revision of the theory is required for all but simple dipole-dipole interactions. In the process of the evaluation, the values of the multipole moments are discussed.

  4. 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...... reasonably expect that the residual part will be close to one and, consequently, the combinatorial-free volume part will be close to the experimental value. For these solutions the main effect of nonideality comes from size/shape differences rather than energetic ones. Thus, it is reasonable to assume...

  5. Accompanying coordinate expansion and recurrence relation method using a transfer relation scheme for electron repulsion integrals with high angular momenta and long contractions

    Energy Technology Data Exchange (ETDEWEB)

    Hayami, Masao [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Seino, Junji [Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Nakai, Hiromi, E-mail: nakai@waseda.jp [Department of Chemistry and Biochemistry, School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555 (Japan); CREST, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520 (Japan)

    2015-05-28

    An efficient algorithm for the rapid evaluation of electron repulsion integrals is proposed. The present method, denoted by accompanying coordinate expansion and transferred recurrence relation (ACE-TRR), is constructed using a transfer relation scheme based on the accompanying coordinate expansion and recurrence relation method. Furthermore, the ACE-TRR algorithm is extended for the general-contraction basis sets. Numerical assessments clarify the efficiency of the ACE-TRR method for the systems including heavy elements, whose orbitals have long contractions and high angular momenta, such as f- and g-orbitals.

  6. A new result on the existence of periodic solutions for Liénard equations with a singularity of repulsive type.

    Science.gov (United States)

    Lu, Shiping

    2017-01-01

    In this paper, the problem of the existence of a periodic solution is studied for the second order differential equation with a singularity of repulsive type [Formula: see text] where [Formula: see text] is singular at [Formula: see text], φ and h are T-periodic functions. By using the continuation theorem of Manásevich and Mawhin, a new result on the existence of positive periodic solution is obtained. It is interesting that the sign of the function [Formula: see text] is allowed to change for [Formula: see text].

  7. Position-space renormalization-group investigation of the spin-3/2 Blume-Emery-Griffiths model with repulsive biquadratic coupling

    Science.gov (United States)

    Bakchich, A.; El Bouziani, M.

    2001-01-01

    Phase transitions of a four-component lattice gas or spin-3/2 Blume-Emery-Griffiths model, with a single-ion uniaxial anisotropy and nearest-neighbour pair interactions, both bilinear and biquadratic, are investigated for two-dimensional lattices using an approximate renormalization-group approach of the Migdal-Kadanoff type. The set of fixed points and flows provide the characteristic phase diagrams, in the case of repulsive biquadratic interaction, featuring four ordered phases including high-entropy ferrimagnetic and staggered quadrupolar phases. Successive phase transitions and multicritical points are also found.

  8. (光压)斥力相互作用在自然界客观存在的宏观证据%Macro evidence of objective reality of the (light pressure)repulsive force interaction in nature

    Institute of Scientific and Technical Information of China (English)

    宋贯一

    2012-01-01

    It is well known that a large number of stars shed light and radiation through out in the universe. Although discovered and verified in 1901, the solar pressure has not been accepted as a natural power due to the repulsive force (solar pressure) interacted each other performed in macro substance (celestial bodies) , which doesn' t shown under the disguise of solar system (solar radiation pressure). that's to say, whether and what changes of macro movement state of the earth happened under solar pressure is the key to confirm the existence of repulsive force as a natural power. A series discoveries by the author shown as below, solar pressure, earth rotation and revolution consists of natural "rolling mill" similar to metal plastic manufacture, through which the solar energy transferred to the earth and expressed as crustal "crushing extension effect" in term of such coupled mechanism in 1991, solar pressure repulsive force is the only factors to control crustal movement and earthquake in 1999, the existence of solar pressure, earth rotation and revolution and obliquity of the ecliptic constitute a physical mechanism as "wobble" means solar energy coupled in earth-sun system in 1992, solar pressure repulsive force is the key to initiate oscillation of rotation axis and generate pole shift and seasonal changes of velocity of earth rotation in 2006 and 2011. All above mentioned make up persuasive evidences given rise to the natural objectivity of light pressure interaction, which play the equal importance to the cosmic evolution as "gravity".%在宇宙中,众多恒星发出的光线充斥于万物之间.光压虽然早在1901年就被人们发现和试验证实,但一直未把它作为一种客观存在的自然力看待.其原因是(光压)斥力相互作用(自然力)主要表现在宇观物体(天体)上,在太阳系内的(太阳光压)斥力作用下,能否证明地球物质的宏观运动状态发生了变化及发生了什么样的变化,则是人们把(光压)

  9. The learned physician as a charismatic healer: Urso of Salerno (flourished end of twelfth century) on incantations in medicine, magic, and religion.

    Science.gov (United States)

    van der Lugt, Maaike

    2013-01-01

    Urso, the last of the great Salernitan physicians, was both an ardent defender of a theoretical, scientific medicine and the first in the medieval West to propose, in his aphorisms, a rational and naturalistic explanation of the healing power of incantations. The article explores this paradox and provides an in-depth analysis of Urso's highly original and hitherto ignored argument, as well as its intellectual and social background. According to Urso, the efficacy of incantations relies not on the power of words, but on the charismatic physician's "aura"-spirits emanating from his body-and the patient's confidence in and conformity with the physician. Urso compares medical incantations to teaching, fascination, demonic magic, sacraments, and prayer. It is argued that Urso's incursions into theology are both a tactic to defend his bold naturalism against accusations of unorthodoxy and a reflection of his ambition to create a comprehensive "science of everything." Urso's text and an English translation are provided in an appendix.

  10. 我国环保产业“十二五”技术发展重点领域%Key Areas of Technical Development on Environmental Protection Industry in China during the "Twelfth Five-year"

    Institute of Scientific and Technical Information of China (English)

    燕中凯; 尚光旭

    2011-01-01

    基于我国环保产业的发展现状及政策背景,介绍了“十二五”我国环保产业发展重点技术领域及发展方向,包括水污染控制、大气污染控制、固体废弃物处理处置、噪声污染控制、土壤污染控制、重金属污染控制、农村面源污染控制等领域。%Based on the present status and policy background of environmental protection industry in China, the key technical areas and developing orientation on environmental protection industry development during the Twelfth Five-year arepresented, key areas such as water pollution control, air pollution control, solid waste treatment and disposal, noise pollution control, soil pollution control, heavy metal control and area source pollution control in rural areas.

  11. NASA/IEEE MSST 2004 Twelfth NASA Goddard Conference on Mass Storage Systems and Technologies in cooperation with the Twenty-First IEEE Conference on Mass Storage Systems and Technologies

    Science.gov (United States)

    Kobler, Ben (Editor); Hariharan, P. C. (Editor)

    2004-01-01

    MSST2004, the Twelfth NASA Goddard / Twenty-first IEEE Conference on Mass Storage Systems and Technologies has as its focus long-term stewardship of globally-distributed storage. The increasing prevalence of e-anything brought about by widespread use of applications based, among others, on the World Wide Web, has contributed to rapid growth of online data holdings. A study released by the School of Information Management and Systems at the University of California, Berkeley, estimates that over 5 exabytes of data was created in 2002. Almost 99 percent of this information originally appeared on magnetic media. The theme for MSST2004 is therefore both timely and appropriate. There have been many discussions about rapid technological obsolescence, incompatible formats and inadequate attention to the permanent preservation of knowledge committed to digital storage. Tutorial sessions at MSST2004 detail some of these concerns, and steps being taken to alleviate them. Over 30 papers deal with topics as diverse as performance, file systems, and stewardship and preservation. A number of short papers, extemporaneous presentations, and works in progress will detail current and relevant research on the MSST2004 theme.

  12. The Development of Service Outsourcing Industry in Daqing in the Twelfth Five-Year Plan Period%“十二五”时期大庆市服务外包产业发展研究

    Institute of Scientific and Technical Information of China (English)

    赵勤

    2012-01-01

      加快服务外包产业发展是“十二五”时期大庆市加快经济发展方式转变和经济转型的有效途径。目前,大庆市服务外包产业面临着产业竞争力不强、人才制约严重等突出问题。推进服务外包产业发展,要科学谋划发展思路、重点领域和产业布局,实施人才优先战略,加快培育骨干企业,推进产业集聚,提速生产性服务业发展%  Speeding up the development of service outsourcing industry is an effective way to accelerate the transformation of the eco-nomic development pattern and economic restructure in Daqing in the Twelfth Five-Year Plan period. The service outsourcing indus-try in Daqing now faces some serious problems in terms of less competitiveness and severe personnel constraints. In order to promote the development of service outsourcing industry, the authorities should plan the development modes, key areas and industrial distribu-tion in a scientific way; implement talent priority strategies; accelerate cultivating backbone enterprises, advance industrial cluster and quicken the development of producer services.

  13. Thought on the Development of Wuhan Trade Logistics during the Twelfth Five-Year Plan%“十二五”期间武汉市商贸物流发展的思考

    Institute of Scientific and Technical Information of China (English)

    熊文杰

    2011-01-01

    武汉是中国内陆重要的商品物流集散地,武汉商贸物流是全市物流业的重要组成部分,“十一五”以来,武汉商贸物流得到了较大的发展,但依然存在诸多不足,本文根据湖北省、武汉市“十二五”的发展规划,对武汉市“十二五”期间商贸物流的发展提出若干建议。%Wuhan is an important distribution center of commodity in China inland. Its trade logistics is the crucial part of Wuhan logistics industry. Since the Eleventh Five-Year Plan for National Economic and Social Develop- ment, Wuhan trade logistics has greatly developed, while there are still many disadvantages. This paper puts forward some suggestions on the development of Wuhan trade logistics in accordance with the twelfth Five-Year Development Plan.

  14. Review on the Development of Industrial Injury Insurance During the Period of the "Twelfth Five-year"%回顾"十二五"时期工伤保险事业的发展

    Institute of Scientific and Technical Information of China (English)

    刘梅

    2015-01-01

    During the "Twelfth Five-year" period, the industrial injury insurance system has being constantly improved, the level of legalization and standardization has been increased, the coverage has been further expanded, the funds supporting ability has been greatly enhanced, and the standard of treatment has been continuously improved. It has played a positive role in protecting the right of the injured employees, promoting further reform and economic development, and maintaining social harmony and stability.%"十二五"时期,工伤保险制度体系不断完善,工伤保险法制化、规范化水平得到提高,工伤保险制度覆盖范围进一步扩大,基金保障能力大幅增强,待遇水平持续提高,为保障工伤职工合法权益、促进深化改革和经济发展、维护社会和谐稳定发挥了积极作用.

  15. “十二五”时期广东节能潜力与实现途径研究%Potential and Implementation of Guangdong's Energy Conservation in the Twelfth Five-Year Plan Period

    Institute of Scientific and Technical Information of China (English)

    吴宏斌

    2012-01-01

    After calculating the energy-saving potential of Guangdong province, this essay shows the energy intensity per GDP of Guangdong can be reduced by 13.3%-19.2% in the Twelfth Five-Year Plan period. To realize the goal of the energy intensity per GDP reduction of 18% from 2011 up to 2015, it is necessary to establish the fiscal compensation and adjustment mechanism based on the increment of energy consumption.%“十二五”时期,广东的节能潜力即单位GDP能耗下降率的潜在空间在13.3%~19.2%之间,为实现国家下达的5年单位GDP能耗下降18%的节能目标,需在全省范围内建立合理的能源消费增量补偿与调节机制。

  16. Probing the Repulsive Core of the Nucleon-Nucleon Interaction via the He4(e ,e'pN) Triple-Coincidence Reaction

    Science.gov (United States)

    Korover, I.; Muangma, N.; Hen, O.; Shneor, R.; Sulkosky, V.; Kelleher, A.; Gilad, S.; Higinbotham, D. W.; Piasetzky, E.; Watson, J. W.; Wood, S. A.; Aguilera, P.; Ahmed, Z.; Albataineh, H.; Allada, K.; Anderson, B.; Anez, D.; Aniol, K.; Annand, J.; Armstrong, W.; Arrington, J.; Averett, T.; Badman, T.; Baghdasaryan, H.; Bai, X.; Beck, A.; Beck, S.; Bellini, V.; Benmokhtar, F.; Bertozzi, W.; Bittner, J.; Boeglin, W.; Camsonne, A.; Chen, C.; Chen, J.-P.; Chirapatpimol, K.; Cisbani, E.; Dalton, M. M.; Daniel, A.; Day, D.; de Jager, C. W.; De Leo, R.; Deconinck, W.; Defurne, M.; Flay, D.; Fomin, N.; Friend, M.; Frullani, S.; Fuchey, E.; Garibaldi, F.; Gaskell, D.; Gilman, R.; Glamazdin, O.; Gu, C.; Gueye, P.; Hamilton, D.; Hanretty, C.; Hansen, J.-O.; Hashemi Shabestari, M.; Holmstrom, T.; Huang, M.; Iqbal, S.; Jin, G.; Kalantarians, N.; Kang, H.; Khandaker, M.; LeRose, J.; Leckey, J.; Lindgren, R.; Long, E.; Mammei, J.; Margaziotis, D. J.; Markowitz, P.; Marti Jimenez-Arguello, A.; Meekins, D.; Meziani, Z.; Michaels, R.; Mihovilovic, M.; Monaghan, P.; Munoz Camacho, C.; Norum, B.; Nuruzzaman, Pan, K.; Phillips, S.; Pomerantz, I.; Posik, M.; Punjabi, V.; Qian, X.; Qiang, Y.; Qiu, X.; Rakhman, A.; Reimer, P. E.; Riordan, S.; Ron, G.; Rondon-Aramayo, O.; Saha, A.; Schulte, E.; Selvy, L.; Shahinyan, A.; Sirca, S.; Sjoegren, J.; Slifer, K.; Solvignon, P.; Sparveris, N.; Subedi, R.; Tireman, W.; Wang, D.; Weinstein, L. B.; Wojtsekhowski, B.; Yan, W.; Yaron, I.; Ye, Z.; Zhan, X.; Zhang, J.; Zhang, Y.; Zhao, B.; Zhao, Z.; Zheng, X.; Zhu, P.; Zielinski, R.; Jefferson Lab Hall A Collaboration

    2014-07-01

    We studied simultaneously the He4(e ,e'p), He4(e ,e'pp), and He4(e ,e'pn) reactions at Q2=2(GeV/c)2 and xB>1, for an (e ,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A =2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum, in a region where the nucleon-nucleon (NN) force is expected to change from predominantly tensor to repulsive. The abundance of neutron-proton pairs is reduced as the nucleon momentum increases beyond ˜500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum. Our data are compared with calculations of two-nucleon momentum distributions in He4 and discussed in the context of probing the elusive repulsive component of the NN force.

  17. A local approximation of fundamental measure theory incorporated into three dimensional Poisson-Nernst-Planck equations to account for hard sphere repulsion among ions

    CERN Document Server

    Qiao, Yu; Chen, Minxin

    2015-01-01

    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 has a very similar form to one term of the LHS model, but LHS...

  18. SSeCKS/AKAP12 induces repulsion between human prostate cancer and microvessel endothelial cells through the activation of Semaphorin 3F.

    Science.gov (United States)

    Xie, Wen; Su, Wei; Zhang, Lijuan; Shang, Qingkun; Su, Bing

    2017-09-02

    Metastasis remains the primary cause of prostate cancer related death. Cancer cells need to contact endothelial cells and disrupt endothelial junctions to cross the endothelium for invasion and metastasis. The suppression of heterotypic repulsion between cancer and endothelial cells allows cancer cells to invade into the surrounding tissue. Here, we demonstrate that SSeCKS/AKAP12 induced repulsion between human prostate cancer and microvessel endothelial cells, which was mediated by an angiogenesis inhibitor Semaphorin 3F. Moreover, we examined AKAP12 and Semaphorin 3F mRNA expression in 42 prostate cancer and 30 benign prostatic hyperplasia tissue samples, and found that the expression of AKAP12 and Semaphorin 3F mRNA was inversely associated with the degree of aggressiveness of prostate cancer cells and tissues. An ordinal logistic regression analysis indicates that there is a positive association between the expression of AKAP12 and Semaphorin 3F in prostate cancer, suggesting that the activation of Semaphorin 3F by SSeCKS/AKAP12 may be involved in prostate cancer progression and metastasis. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Dissection of two quantitative trait loci for grain weight linked in repulsion on the long arm of chromosome 1 of rice(Oryza sativa L.)

    Institute of Scientific and Technical Information of China (English)

    Liang; Guo; Kai; Wang; Junyu; Chen; Derun; Huang; Yeyang; Fan; Jieyun; Zhuang

    2013-01-01

    Grain weight is a key determinant of grain yield in rice. Three sets of rice populations with overlapping segregating regions in isogenic backgrounds were established in the generations of BC2 F5, BC2 F6 and BC2 F7, derived from Zhenshan 97 and Milyang 46, and used for dissection of quantitative trait loci(QTL) for grain weight. Two QTL linked in repulsion phase on the long arm of chromosome 1 were separated. One was located between simple sequence repeat(SSR) markers RM11437 and RM11615, having a smaller additive effect with the enhancing allele from the maintainer line Zhenshan 97 and a partially dominant effect for increasing grain weight. The other was located between SSR markers RM11615 and RM11800, having a larger additive effect with the enhancing allele from the restorer line Milyang 46 and a partially dominant effect for increasing grain weight. When the two QTL segregated simultaneously, a residual additive effect with the enhancing allele from Milyang 46 and an over-dominance effect for increasing grain weight were detected. This suggests that dominant QTL linked in repulsion phase might play an important role in heterosis in rice. Our study also indicates that the use of populations with overlapping segregating regions in isogenic backgrounds is helpful for the dissection of minor linked QTL.

  20. Power Outages

    Science.gov (United States)

    ... Thunderstorms & Lightning Tornadoes Tsunamis Volcanoes Wildfires Main Content Power Outages This page provides basic safety tips and ... during and after a power outage. Before a Power Outage Build or restock your emergency preparedness kit , ...

  1. Wind Power

    OpenAIRE

    Makhalas, Kharsan Al; Alsehlli, Faisal

    2015-01-01

    This Bachelor thesis has been written at the Blekinge Institute of Technology. This thesis concentrates on the wind power and their components, also the large wind farm is studied. The electrical power is generated by using the power in wind to drive a wind turbine to produce mechanical power. This mechanical power can be converted into electrical power by using electrical induction generators. There are two types of the wind turbines, the horizontal axis and vertical axis wind turbine, where...

  2. Analysis of Characteristics of Micromachined Electrostatic Repulsive Actuator%微加工静电排斥驱动器特性分析

    Institute of Scientific and Technical Information of China (English)

    陶逢刚; 姚军; 汪为民; 庄须叶; 张恒; 胡放荣

    2011-01-01

    基于非均匀电场可产生静电排斥力的原理,设计制造了单元尺寸为300 μm的MEMS静电排斥型离面驱动器.此驱动器不受静电吸合效应的限制,行程较传统静电吸引型驱动器有显著提高.利用表面硅工艺完成了该驱动器的加工.为研究静电排斥型驱动器的动态响应特性,建立了该驱动器的等效模型并利用数值计算方法分析了驱动器的压膜阻尼特性和幅频特性.采用白光干涉仪对微驱动器进行了静态和动态测试,测试结果表明,所设计的MEMS静电排斥驱动器在100V的电压下实现了2.1μm的驱动位移,工作带宽为2kHz,具有较快的响应速度.%Based upon the principle that an asymmetric electric field can generate a repulsive force, a micro out-of-plane electrostatic repulsive actuator with a unit dimension of 300 urn is designed and fabricated. The stroke of this kind of actuator is far larger than the traditional attractive actuators for it is not limited by the "Pull-in" phenomenon. The actuator is prepared using a surface micromachining polysilicon processes. To study the dynamic performance of the actuator, an equivalent model of the electrostatic repulsive micro driver is proposed. The squeeze air film damping -effect and frequency response of the micro driver are analyzed based upon the numerical method. The static and dynamic characteristics of the actuator are tested using a white light interferometer. The results show that the static displacement of this kind of actuator reaches 2.1 μm at 100 V, and the actuator has a wide working bandwidth of 2 kHz and a fast response μ

  3. 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

  4. 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.

  5. Switching between attractive and repulsive Coulomb-interaction-mediated drag in an ambipolar GaAs/AlGaAs bilayer device

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, B.; Croxall, A. F.; Waldie, J., E-mail: jw353@cam.ac.uk; Sfigakis, F.; Farrer, I.; Beere, H. E.; Ritchie, D. A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Das Gupta, K. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Department of Physics, Indian Institute of Technology Bombay, Mumbai 400076 (India)

    2016-02-08

    We present measurements of Coulomb drag in an ambipolar GaAs/AlGaAs double quantum well structure that can be configured as both an electron-hole bilayer and a hole-hole bilayer, with an insulating barrier of only 10 nm between the two quantum wells. Coulomb drag resistivity is a direct measure of the strength of interlayer particle-particle interactions. We explore the strongly interacting regime of low carrier densities (2D interaction parameter r{sub s} up to 14). Our ambipolar device design allows a comparison between the effects of the attractive electron-hole and repulsive hole-hole interactions and also shows the effects of the different effective masses of electrons and holes in GaAs.

  6. High pressure investigations on hydrous magnesium silicate-phase A using first principles calculations: H---H repulsion and changes in hydrogen bond geometry with compression

    Science.gov (United States)

    Poswal, H. K.; Sharma, Surinder; Sikka, S. K.

    2009-09-01

    We have carried out first principles structural relaxation calculations on the hydrous magnesium silicate Phase A (Mg7Si2O8(OH)6) under high pressures. Our results show that phase A does not undergo any phase transition upto ~ 45 GPa. We find that non-bonded H--H distance reaches a limiting value of 1.85 angstrom at about 45 GPa. The H--H repulsive strain releasing mechanism in Phase A is found to be dramatically different from the hydrogen bond bending one that was proposed by Hofmeister et al1 for Phase B. It is based on the reduction of one of the O-H bond distances with compression.

  7. Size-controlled starch nanoparticles prepared by self-assembly with different green surfactant: The effect of electrostatic repulsion or steric hindrance.

    Science.gov (United States)

    Li, Xiaojing; Qin, Yang; Liu, Chengzhen; Jiang, Suisui; Xiong, Liu; Sun, Qingjie

    2016-05-15

    To study the control effect of surfactants in the process of formation of starch nanoparticles by self-assembly, different surfactants (sodium dodecyl sulfate (SDS), polysorbate 80 (Tween 80), and sorbitan monooleate (Span 80) were added during the fabrication of waxy corn starch nanoparticles (WCSNPs) and potato starch nanoparticles (PSNPs), and their characteristics were determined and compared. The results showed that WCSNPs with SDS and Tween 80 had smaller particle size (28-35 nm and 15-24 nm, respectively) than that of WCSNPs (50-120 nm). The surfactants significantly increased the dispersion and thermal stability of nanoparticles. Short-chain amylose debranched from waxy corn starch had a lower degree of polymerization than that debranched from potato starch and were easier to retrograde, resulting in higher gelatinization enthalpy of WCSNPs. However, PSNPs were smaller in size and achieved better stability than WCSNPs due to stronger electrostatic repulsion caused by a higher absolute value of zeta potential.

  8. Analyzing the vibrational response of an AFM cantilever in liquid with the consideration of tip mass by comparing the hydrodynamic and contact repulsive force models in higher modes

    Science.gov (United States)

    Korayem, Moharam Habibnejad; Nahavandi, Amir

    2017-04-01

    This paper investigates the vibration of a tapping-mode Atomic Force Microscope (AFM) cantilever covered with two whole piezoelectric layers in a liquid medium. The authors of this article have already modeled the vibration of a cantilever immersed in liquid over rough surfaces. Five new ideas have been considered for improving the results of the previous work. Mass and damping of a cantilever probe tip have been considered. Since the probe tip of an AFM cantilever has a mass, which can itself affect the natural frequency of vibration, the significance of this mass has been explored. Also, two hydrodynamic force models for analyzing the mass and damping added to a cantilever in liquid medium have been evaluated. In modeling the vibration of a cantilever in liquid, simplifications are made to the theoretical equations used in the modeling, which may make the obtained results different from those in the real case. So, two hydrodynamic force models are introduced and compared with each other. In addition to the already introduced DMT model, the JKR model has been proposed. The forces acting on a probe tip have attractive and repulsive effects. The attractive Van der Waals force can vary depending on the surface smoothness or roughness, and the repulsive contact force, which is independent of the type of surface roughness and usually varies with the hardness or softness of a surface. When the first mode is used in the vibration of an AFM cantilever, the changes of the existing physical parameters in the simulation do not usually produce a significant difference in the response. Thus, three cantilever vibration modes have been investigated. Finally, an analytical approach for obtaining the response of equations is presented which solves the resulting motion equation by the Laplace method and, thus, a time function is obtained for cantilever deflection is determined. Also, using the COMSOL software to model a cantilever in a liquid medium, the computed natural

  9. 民办高校制定“十二五”发展规划的思考%Thinking of Development Outline Making of Non-public Colleges and Universities during "the Twelfth Five-year-plan"

    Institute of Scientific and Technical Information of China (English)

    刘龙刚; 朱海玲

    2011-01-01

    “十二五”时期是我国全面建设小康社会的关键时期,国民经济增长方式的转变、经济社会发展战略的调整对民办高校教育改革和发展提出了新要求,民办高校发展的目标、重点、方式亦将发生深刻变化。本文首先从办学规模、办学模式、办学质量、办学特色、对外交流等五方面分析了民办高校的历程与成就,然后从国民经济增长方式和经济社会发展战略的调整对民办教育产生深远影响、国家中长期教育改革和发展规划纲要为民办高校发展指明了方向、民办高校发展仍然面临诸多自身内部问题等分析了民办高校发展所面临的形势;最后,从体制依托、服务转型、内涵发展、风险防范等四个方面提出了民办高校“十二五”时期发展对策与建议。为民办高校制定和实施“十二五”发展规划提供参考。%"The twelfth five-year-plan" period is a critical period of China's building a moderately prosperous society. National economic growth changes and adjustment of economic and social development strategy put forward new demands for reform and development of nonpublic colleges and universities. The objectives, priorities and methods of their development will also undergo profound changes. Firstly, this paper analyzes the history and achievements in the aspect of school size, school model, school quality, school characteristics, and foreign ex change, etc. Then it analyzes the situation which non-public colleges and universities are facing in the following aspects, e.g. , national economic growth method and adjustment of economic and social development strategy have a profound impact on non-public education, the state long-term education reform and development plan outline points out the direction for the development of non-public colleges and universities, development of private colleges and universities still face many problems within their own

  10. Prospect of agricultural informationization development in China during "the Twelfth Five-Year Plan"%“十二五”时期中国农业信息化发展前瞻

    Institute of Scientific and Technical Information of China (English)

    贺玢

    2012-01-01

    "十二五"时期,中国农业信息化正面临经济快速协调发展、城乡一体化、发展现代农业、新一代信息技术革命等有利机遇,但同时也面临社会认识不到位、农业信息技术产业发展缓慢、农业信息化扶持政策不配套、体制和机制不适应等因素的制约。中国农业信息化的发展趋势是:农业信息化由政府推动向需求拉动转变,农业信息服务向扁平化方向发展,农业信息化由单项技术应用向综合技术集成应用转变。%During the Twelfth Five-year Plan period,China's agricultural informationization faces many opportunities and challenges.First the paper analyzes the opportunities: the rapid economic development,urban-rural integration,the development of modern agriculture,the revolution of new generation information technology.Then the challenges are reviewed: social cognition is beyond the informationization development,agricultural information technology develops slowly,policy support on agricultural informationization does not fit the needs,institutions and mechanisms do not meet the restriction.Then the development tendency is proposed: agricultural informationization will transfer from government promotion to demand promotion,from point-to-point to flat structure,from single technology application to integrated application.

  11. “十二五”中国通胀治理的战略运筹%China's Strategic Operations for Controlling Inflation in the Twelfth Five-year Plan Period

    Institute of Scientific and Technical Information of China (English)

    杨枝煌

    2011-01-01

    China's inflation in the first year of the Twelfth Five-year Plan arises from four main reasons: liquidity overrun,expectation of inflation,input of US dollars,and rise of costs.To control this round of inflation scientifically,we must have an over-all vision and a long-term plan and make good use of economic,political,legal and other measures.In particular,we must work out strategic plans in finance,taxation and administration,relieve the expectation of inflation,use inflation as a tool for economic development and dilute the stress of Renminbi appreciation by inflation.%导致"十二五"开局之年中国通胀主要有四大因素:货币超发、预期催化、美元输入、成本推动。为科学治理此轮通胀,必须具有全局视野和长远眼光,利用经济、政治、法律等综合手段,尤其要在金融、财税、行政方面做出战略规划,控制好通胀的同时控制好通胀预期,把通胀作为经济发展的一种工具,以通胀对冲稀释人民币升值压力。

  12. Research on Tianjin Trade Circulation Industry Development During the Twelfth Five-Year Plan%“十二五”时期天津商贸流通业的发展重点研究

    Institute of Scientific and Technical Information of China (English)

    钱伟荣; 孙春华; 王桂英

    2012-01-01

    根据《天津市商贸流通业发展"十二五"规划》纲要,天津市商贸流通业在"十二五"期间承担着汇聚商业巨头、广泛辐射周边、成为在国内国际具有重要影响的中国北方商贸中心的目标,将建设成为在国内外具有重要影响、独具魅力的中国北方商贸中心和国际性时尚消费之都。本文在分析天津市商贸流通业的现状和存在问题、发展环境与趋势的基础上,提出了今后发展十大重点任务,概括为"实施一战略,构建三体系,开展四工程,完善两机制"。%Based on During the Twelfth Five-Year Plan for the Development of Tianjin Trade Circulation Industry, the said industry will be taking the important part of becoming the business center and international city of fashion consumption in northern China which gathers business tycoons and intensively influences the surrounding areas. The article analyses the present situation, problems and environment of the said industry, putting forward a tentative idea for the ten key tasks which can be generalized into one strategy, three systems, four projects and two systems.

  13. “十二五”时期武汉经济结构转型升级评估%Economic Structure of Wuhan Transformation and Upgrading Assessment During"Twelfth five-year"Period

    Institute of Scientific and Technical Information of China (English)

    汪涛; 汪子奇; 李红艳

    2016-01-01

    通过比较19个副省级以上城市经济结构,结合武汉市“十二五”规划指标完成情况,评估武汉经济结构转型程度,发现武汉经济结构转型进展迟缓,主要原因在于转型动力不足、结构协同呈现明显分化,使得现有经济结构与经济实力、经济增长态势、支撑未来经济持续快速增长需要三个均不匹配。在“十三五”时期,武汉应坚持“五驱并举、协同升级”的思路。%By comparing 19 vice provincial level city economic structure, combined with the planning targets completion of Wuhan during "twelfth five-year" period, assess the extent of the economic structure transformation of Wuhan, found slow progress in economic restructuring, the reason is mainly the transformation underpowered and significant differentiation in col-laborative structure. This leaded to the existing economic structure and economic strength, economic growth, requires of sup-porting the future sustained and rapid economic growth do not match. Wuhan should adhere to the "five drives simultaneously, synergy upgrade "ideas during "thirteen five" period.

  14. Prospect of Biomanufacturing Industry During the Next National Twelfth Five-Year Plan Period%生物制造产业“十二五”时期发展展望

    Institute of Scientific and Technical Information of China (English)

    石维忱

    2011-01-01

    The biomanufacturing industry is the important guarantee to support sustainable development of social economy.Biomanufacturing technology is applied widely in chemical industry,food industry,pharmacy industry,paper industry,textile industry,mining industry,energy industry and environmental protection.Biomanufacturing is of great strategic significance to accelerate economic restructuring,transform growth mode,propel economical development,clean development,and safety development,and establish green and sustainable industrial economy system.The current status and existed problems of biomanufacturing industry were presented.The development strategies,directions,and goals of biomanufacturing industry during the next National Twelfth Five-Year Plan period were proposed.%生物制造产业是支撑社会经济可持续发展的重要保障,生物制造技术广泛应用于化工、食品、制药、造纸、纺织、采矿、能源以及环境保护等许多重要领域.生物制造对于我国加快调整经济结构、转变增长方式,节约发展、清洁发展、安全发展,建立绿色与可持续的产业经济体系具有重大战略意义.论述了生物制造产业的发展现状和存在的问题,并对其在"十二五"期间的发展思路、发展方向、发展目标进行了展望.

  15. Wind power in power systems

    CERN Document Server

    Ackermann, Thomas

    2012-01-01

    The second edition of the highly acclaimed Wind Power in Power Systems has been thoroughly revised and expanded to reflect the latest challenges associated with increasing wind power penetration levels. Since its first release, practical experiences with high wind power penetration levels have significantly increased. This book presents an overview of the lessons learned in integrating wind power into power systems and provides an outlook of the relevant issues and solutions to allow even higher wind power penetration levels. This includes the development of standard wind turbine sim

  16. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    energy at the end-user should also be set up. Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources will be 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 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...

  17. Electric Power

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ China Council for the Promotion of International Trade Electric Power Industry Office (CCPIT Electric Power), one of the pro-fessional industrial branches of China Council for the Promotion of International Trade (CCPIT), was established in 2006.

  18. 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....

  19. Normative Power

    DEFF Research Database (Denmark)

    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....... The second meaning of normative power is as a form of power that is ideational rather than material or physical. The third meaning of normative power is as a characterisation of an ideal type of international actor. Empirical studies of normative forms of power have analysed both the causal and constitutive...... 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...

  20. 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...... 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...... interfaces. The focus of the chapter is on the design of power talk solutions for DC microgrids with droop control. Specifically, the chapter presents the power talk implementation through modification of the droop parameters of the primary control loop, and investigates the design of modulation schemes...

  1. Molecular dynamics simulations of classical stopping power.

    Science.gov (United States)

    Grabowski, Paul E; Surh, Michael P; Richards, David F; Graziani, Frank R; Murillo, Michael S

    2013-11-22

    Molecular dynamics can provide very accurate tests of classical kinetic theory; for example, unambiguous comparisons can be made for classical particles interacting via a repulsive 1/r potential. The plasma stopping power problem, of great interest in its own right, provides an especially stringent test of a velocity-dependent transport property. We have performed large-scale (~10(4)-10(6) particles) molecular dynamics simulations of charged-particle stopping in a classical electron gas that span the weak to moderately strong intratarget coupling regimes. Projectile-target coupling is varied with projectile charge and velocity. Comparisons are made with disparate kinetic theories (both Boltzmann and Lenard-Balescu classes) and fully convergent theories to establish regimes of validity. We extend these various stopping models to improve agreement with the MD data and provide a useful fit to our results.

  2. 基于静电排斥力的大冲程MEMS变形镜%Large-Stroke MEMS Deformable Mirrors Based on Electrostatic-Repulsive-Force

    Institute of Scientific and Technical Information of China (English)

    陈科帆; 姚军; 高福华; 汪为民; 倪祖高

    2011-01-01

    A large-stroke electrostatic-repulsive-force MEMS deformable mirror was designed and fabricated. This deformable mirror was prepared using a surface-micromachining polysilicon process, and consisted of three polysilicon structural layers and a metal reflective layer. Three types of the mirrors with different actuator electrodes arrangements were investigated by finite element analysis, and measured with a scanning white light interferometer. The results show that the displacement of the electrostatic-repulsive-force deformable mirrors is more than 1.7 μm at 200 V, and the stroke of which is larger than that of conventional electrostatic-attractive-force deformable mirrors. Additionally, the deformable mirror has the largest stroke of 2.42 μm at 210 V with the third polysilicon layer as the fringe electrode.%设计并制造了一种基于静电排斥力的大冲程MEMS变形镜,此变形镜采用了三个多晶硅结构层和一个金属反射层的设计.利用表面硅工艺完成了变形镜的加工,结合有限元分析软件和白光干涉仪对三种不同驱动器电极空间分布方式的静电排斥型变形镜进行了分析和研究.测试结果表明,静电排斥型变形镜在200V下能实现1.7 μm以上的位移,冲程较传统静电吸引型变形镜有显著提高.在相同电压下,第三层多晶硅作为边缘电极时的变形镜获得的位移最大,在210 V下达到2.42 μm.

  3. 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

  4. Flower power; Flower-Power

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, Karsten

    2010-08-15

    Scientists of Kassel university developed a concept for producing heat and electric power from grassland biomass. This strategy of decentral heat and power supply will also contribute to conservation goals. (orig.)

  5. Mid-term Evaluation of Hangzhou Environmental Protection Planning during “Twelfth Five-year” Plan%杭州市“十二五”环境保护规划中期评估研究

    Institute of Scientific and Technical Information of China (English)

    叶敏; 卢滨; 施军峰

    2015-01-01

    杭州市“十二五”环保规划已实施过半,为了评估规划的实施效果,根据规划内容分析评估了规划指标、主要任务、重点工程、政策措施等四方面的完成情况,梳理了实施过程中存在的三个问题。一是污染物减排动力依然大,二是环境质量改善任重道远,三是隐性污染威胁环境安全。针对存在问题,提出了强化领导健全机制、落实问责制度、加大“三清”行动(清洁水源、清洁空气、清洁土壤)力度、加大产业转型力度、加强环境依法建设、加大环保投入力度等六项对策措施。%Hangzhou“Twelfth Five-year” environmental protection plan has been implemented for 3 years.In order to eval-uate the effect of planning, three main problems and their corresponding countermeasures have been put forward according to the plan, the index, main tasks, key projects and policy measures.The problems includes large pollutant emissions, difficult to im-prove the quality of the environment , the recessive pollution threatening the safety of the environment.In view of the existing problems, this paper puts forward to 6 countermeasures, such as strengthening the leadership mechanism, implementing the re-sponsibility system, strengthening the “three cleaning action” ( cleaning water action, cleaning air action, cleaning soil action) , strengthening environmental law construction, increasing investment in environmental protection.

  6. 安全生产"十二五"规划若干统计指标考量%Research on several indicators in the twelfth five-year program for work safety

    Institute of Scientific and Technical Information of China (English)

    刘铁民; 任智刚

    2011-01-01

    生产安全事故统计指标是安全生产监督管理及宏观决策重要依据.为进一步完善我国职业伤害统计指标体系,对安全生产规划中若干指标的科学性和实用性以及存在问题进行了探索.在进行初步实验计算、理论分析和国内外安全生产事故主要统计指标特点对比研究后,提出:在该规划指标中调整或删去"亿元国内生产总值死亡率";增加非致死性事故统计数据,以能更好代表职业伤害事故总量;适度应用重特大事故起数指标和提高十万人死亡率统计指标精确性等几点建议.作者认为应加强职业伤害指标体系研究,从而尽快实现我国统计指标与国际接轨,在中重现中国职业伤害统计数据.%Occupational injury indicators play important roles in work safety administration and macro decision-making.To further improve the system of statistical indicators of occupational injury, the scientific and practicability as well as problems about several occupational indicators in the Twelfth Five-year program for work safety were studied.Based on preliminary calculation, theoretical analysis and comparison of main occupational injury indicators at home and abroad, we gave a few suggestions, namely adjusting or deleting the indicator fatal rate per one hundred million GDP, increasing non-fatal accident statistic indicators to better representative of the total occupational injuties, applying indicators of major accidents appropriately and increasing accuracy of the indicator fatal numbers per 100000 workers.We advised that we should strengthen research on occupational injury indicators so as to consistent with international standards of occupational injury statistical indicators soon as possible, and to make occupational injury data of China return in the Yearbook of International Labor Statistics.

  7. 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

  8. Approaching the nucleon-nucleon short-range repulsive core via the 4He(e,e'pN) triple coincidence reaction

    CERN Document Server

    Muangma, I Korover N; Shneor, R; Sulkosky, V; Kelleher, A; Gilad, S; Higinbotham, D W; Watson, E Piasetzky J; Wood, S; Rakhman, Abdurahim; Aguilera, P; Ahmed, Z; Albataineh, H; Allada, K; Anderson, B; Anez, D; Aniol, K; Annand, J; Armstrong, W; Arrington, J; Averett, T; Badman, T; Baghdasaryan, H; Bai, X; Beck, A; Beck, S; Bellini, V; Benmokhtar, F; Bertozzi, W; Bittner, J; Boeglin, W; Camsonne, A; Chen, C; Chen, J -P; Chirapatpimol, K; Cisbani, E; Dalton, M; Daniel, A; Day, D; de Jager, C W; De Leo, R; Deconinck, W; Defurne, M; Flay, D; Fomin, N; Friend, M; Frullani, S; Fuchey, E; Garibaldi, F; Gaskell, D; Gilman, R; Glamazdin, O; Gu, C; Gueye, P; Hamilton, D; Hanretty, C; Hansen, O; Shabestari, M Hashemi; Holmstrom, T; Huang, M; Iqbal, S; Jin, G; Kalantarians, N; Kang, H; Khandaker, M; LeRose, J; Leckey, J; Lindgren, R; Long, E; Mammei, J; Margaziotis, D J; Markowitz, P; Jimenez-Arguello, A Marti; Meekins, D; Meziani, Z; Michaels, R; Mihovilovic, M; Monaghan, P; Camacho, C Munoz; Norum, B; Nuruzzaman,; Pan, K; Phillips, S; Pomerantz, I; Posik, M; Punjabi, V; Qian, X; Qiang, Y; Qiu, X; Reimer, P E; Riordan, S; Ron, G; Rondon-Aramayo, O; Saha, A; Schulte, E; Selvy, L; Shahinyan, A; Sirca, S; Sjoegren, J; Slifer, K; Solvignon, P; Sparveris, N; Subedi, R; Tireman, W; Wang, D; Weinstein, L B; Wojtsekhowski, B; Yan, W; Yaron, I; Ye, Z; Zhan, X; Zhang, J; Zhang, Y; Zhao, B; Zhao, Z; Zheng, X; Zhu, P; Zielinski, R

    2014-01-01

    We measured simultaneously the 4He(eep), 4He(eepp), and 4He(e,e'pn) reactions at Q^2=2 [GeV/c]2 and x_B>1, for a (e,e'p) missing-momentum range of 400 to 830 MeV/c. The knocked-out proton was detected in coincidence with a proton or neutron recoiling almost back to back to the missing momentum, leaving the residual A=2 system at low excitation energy. These data were used to identify two-nucleon short-range correlated pairs and to deduce their isospin structure as a function of missing momentum in a region where the nucleon-nucleon force is expected to change from predominantly tensor to repulsive. Neutron-proton pairs dominate the high-momentum tail of the nucleon momentum distributions, but their abundance is reduced as the nucleon momentum increases beyond ~500 MeV/c. The extracted fraction of proton-proton pairs is small and almost independent of the missing momentum in the range we studied. Our data are compared with ab-initio calculations of two-nucleon momentum distributions in 4He.

  9. The influence of halides in polyoxotitanate cages; dipole moment, splitting and expansion of d-orbitals and electron-electron repulsion.

    Science.gov (United States)

    Hanf, Schirin; Matthews, Peter D; Li, Ning; Luo, He-Kuan; Wright, Dominic S

    2017-01-03

    Metal-doped polyoxotitanate (M-POT) cages have been shown to be efficient single-source precursors to metal-doped titania [TiO2(M)] (state-of-the-art photocatalytic materials) as well as molecular models for the behaviour of dopant metal ions in bulk titania. Here we report the influence halide ions have on the optical and electronic properties of a series of halide-only, and cobalt halide-'doped' POT cages. In this combined experimental and computational study we show that halide ions can have several effects on the band gaps of halide-containing POT cages, influencing the dipole moment (hole-electron separation) and the structure of the valance band edge. Overall, the band gap behaviour stems from the effects of increasing orbital energy moving from F to I down Group 17, as well as crystal-field splitting of the d-orbitals, the potential effects of the Nephelauxetic influence of the halides and electron-electron repulsion.

  10. SrGAP2-Dependent Integration of Membrane Geometry and Slit-Robo-Repulsive Cues Regulates Fibroblast Contact Inhibition of Locomotion.

    Science.gov (United States)

    Fritz, Rafael Dominik; Menshykau, Denis; Martin, Katrin; Reimann, Andreas; Pontelli, Valeria; Pertz, Olivier

    2015-10-12

    Migrating fibroblasts undergo contact inhibition of locomotion (CIL), a process that was discovered five decades ago and still is not fully understood at the molecular level. We identify the Slit2-Robo4-srGAP2 signaling network as a key regulator of CIL in fibroblasts. CIL involves highly dynamic contact protrusions with a specialized actin cytoskeleton that stochastically explore cell-cell overlaps between colliding fibroblasts. A membrane curvature-sensing F-BAR domain pre-localizes srGAP2 to protruding edges and terminates their extension phase in response to cell collision. A FRET-based biosensor reveals that Rac1 activity is focused in a band at the tip of contact protrusions, in contrast to the broad activation gradient in contact-free protrusions. SrGAP2 specifically controls the duration of Rac1 activity in contact protrusions, but not in contact-free protrusions. We propose that srGAP2 integrates cell edge curvature and Slit-Robo-mediated repulsive cues to fine-tune Rac1 activation dynamics in contact protrusions to spatiotemporally coordinate CIL.

  11. 核心词汇折射中国测绘地理信息发展方向标——从国家及各地区“十二五”《纲要》看中国测绘地理信息的发展脉络%The Core Vocabulary of Refraction Mapping Geographic Information Development Direction in China:From National and Regional "Twelfth Five" "Outline" See China Surveying and Mapping Geographic Information Development

    Institute of Scientific and Technical Information of China (English)

    桂德竹; 徐坤; 刘芳

    2013-01-01

    Realization of Surveying and mapping geographic information science development, the government needs to include the local national economic and social development of " Twelfth Five" , and to give strong support and promote. Through the national and regional economic and social development of " Twelfth Five" program related to surveying and mapping geographic information of high frequency vocabulary comparison, analysis of " Twelfth Five" " during our mapping geographic information development direction.%实现测绘地理信息科学发展,需要各级政府将其列入本地区国民经济和社会发展“十二五”规划,并给予强有力的支持和推动.通过国家及各地区的国民经济和社会发展“十二五”规划纲要中有关测绘地理信息的高频词汇比较,解析“十二五”期间我国测绘地理信息的发展方向.

  12. Case Studies in Policy Making. Twelfth Edition

    Science.gov (United States)

    2010-01-01

    Washington or Bogota —for a military build-up without a commensurate effort to address the root causes of the conflict through programs focusing on poverty...been a place of importance at the junction of the Blue and White Nile rivers . Much of the land was converted to Christianity in the sixth century and...government in Darfur, in May 2008, the JEM succeed- ed in striking Omdurman—a town just across the Nile River from the capital, Khartoum. Moreover, when

  13. Reassessing Power

    Institute of Scientific and Technical Information of China (English)

    CHARLES; K.EBINGER; JOHN; P.BANKS

    2011-01-01

    Fukushima accident increases global concern over nuclear safety The accident at the Fukushima Daiichi Nuclear Power Plant in Japan has had an immediate impact on resurgent interest in nuclear power worldwide.Numerous governments have announced plans to re-examine nuclear energy policy and review the safety of their reactors and the adequacy of their regulatory frameworks.

  14. Power Drain

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Rising coal prices mean dwindling profits for China’s power plants. In some cases,they have forced plants to close their doors If electricity prices were not raised together with fuel prices, the country’spower plants could not survive. This isthe common voice of China’s power plants now.

  15. Power Source

    Science.gov (United States)

    Schooley, Michael L.

    2010-01-01

    Principals are powerful: They are the primary catalysts for creating a lasting foundation for learning, driving school and student performance, and shaping the long-term impact of school improvement efforts. Yet few principals would characterize themselves as powerful. Rather, they're self-effacing, adaptable, pragmatic, and quick to share credit…

  16. Diastatic power

    Science.gov (United States)

    diastatic power: Diastatic power, abbreviated DP, is the total activity of malt starch degrading enzymes that hydrolyze starch to fermentable sugars. The starch degrading enzymes contributing to this process are a-amylase, ß-amylase, limit dextrinase, and a-glucosidase. The driving force for DP a...

  17. Power system

    Science.gov (United States)

    Hickam, Christopher Dale

    2008-03-18

    A power system includes a prime mover, a transmission, and a fluid coupler having a selectively engageable lockup clutch. The fluid coupler may be drivingly connected between the prime mover and the transmission. Additionally, the power system may include a motor/generator drivingly connected to at least one of the prime mover and the transmission. The power-system may also include power-system controls configured to execute a control method. The control method may include selecting one of a plurality of modes of operation of the power system. Additionally, the control method may include controlling the operating state of the lockup clutch dependent upon the mode of operation selected. The control method may also include controlling the operating state of the motor/generator dependent upon the mode of operation selected.

  18. Liquid-vapor phase diagram and surface properties in oppositely charged colloids represented by a mixture of attractive and repulsive Yukawa potentials.

    Science.gov (United States)

    Chapela, Gustavo A; del Río, Fernando; Alejandre, José

    2013-02-07

    The liquid-vapor phase diagrams of equal size diameter σ binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Ferńandez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006); A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006)]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length κ. Caballero found stability for values of κσ up to 20 while Fortini reported stability for κσ up to 20 while Fortini reported stability for κσ ≤ 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of κσ. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of κσ > 20 and that the critical temperatures have a maximum value at around κσ = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials.

  19. Nerve repulsion by the lens and cornea during cornea innervation is dependent on Robo-Slit signaling and diminishes with neuron age.

    Science.gov (United States)

    Schwend, Tyler; Lwigale, Peter Y; Conrad, Gary W

    2012-03-01

    The cornea, the most densely innervated tissue on the surface of the body, becomes innervated in a series of highly coordinated developmental events. During cornea development, chick trigeminal nerve growth cones reach the cornea margin at embryonic day (E)5, where they are initially repelled for days from E5 to E8, instead encircling the corneal periphery in a nerve ring prior to entering on E9. The molecular events coordinating growth cone guidance during cornea development are poorly understood. Here we evaluated a potential role for the Robo-Slit nerve guidance family. We found that Slits 1, 2 and 3 expression in the cornea and lens persisted during all stages of cornea innervation examined. Robo1 expression was developmentally regulated in trigeminal cell bodies, expressed robustly during nerve ring formation (E5-8), then later declining concurrent with projection of growth cones into the cornea. In this study we provide in vivo and in vitro evidence that Robo-Slit signaling guides trigeminal nerves during cornea innervation. Transient, localized inhibition of Robo-Slit signaling, by means of beads loaded with inhibitory Robo-Fc protein implanted into the developing eyefield in vivo, led to disorganized nerve ring formation and premature cornea innervation. Additionally, when trigeminal explants (source of neurons) were oriented adjacent to lens vesicles or corneas (source of repellant molecules) in organotypic tissue culture both lens and cornea tissues strongly repelled E7 trigeminal neurites, except in the presence of inhibitory Robo-Fc protein. In contrast, E10 trigeminal neurites were not as strongly repelled by cornea, and presence of Robo-Slit inhibitory protein had no effect. In full, these findings suggest that nerve repulsion from the lens and cornea during nerve ring formation is mediated by Robo-Slit signaling. Later, a shift in nerve guidance behavior occurs, in part due to molecular changes in trigeminal neurons, including Robo1 downregulation

  20. Liquid-vapor phase diagram and surface properties in oppositely charged colloids represented by a mixture of attractive and repulsive Yukawa potentials

    Science.gov (United States)

    Chapela, Gustavo A.; del Río, Fernando; Alejandre, José

    2013-02-01

    The liquid-vapor phase diagrams of equal size diameter σ binary mixtures of screened potentials have been reported for several ranges of interaction using Monte Carlo simulation methods [J. B. Caballero, A. M. Puertas, A. Ferńandez-Barbero, F. J. de las Nieves, J. M. Romero-Enrique, and L. F. Rull, J. Chem. Phys. 124, 054909 (2006), 10.1063/1.2159481; A. Fortini, A.-P. Hynninen, and M. Dijkstra, J. Chem. Phys. 125, 094502 (2006), 10.1063/1.2335453]. Both works report controversial results about the stability of the phase diagram with the inverse Debye screening length κ. Caballero found stability for values of κσ up to 20 while Fortini reported stability for κσ up to 20 while Fortini reported stability for κσ ⩽ 4. In this work a spinodal decomposition process where the liquid and vapor phases coexist through an interface in a slab geometry is used to obtain the phase equilibrium and surface properties using a discontinuous molecular dynamics simulations for mixtures of equal size particles carrying opposite charge and interacting with a mixture of attractive and repulsive Yukawa potentials at different values of κσ. An crude estimation of the triple point temperatures is also reported. The isothermal-isobaric method was also used to determine the phase stability using one phase simulations. We found that liquid-vapor coexistence is stable for values of κσ > 20 and that the critical temperatures have a maximum value at around κσ = 10, in agreement with Caballero et al. calculations. There also exists a controversy about the liquid-vapor envelope stability of the pure component attractive Yukawa model which is also discussed in the text. In addition, details about the equivalence between continuous and discontinuous molecular dynamics simulations are given, in the Appendix, for Yukawa and Lennard-Jones potentials.

  1. Power Talk

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Loh, Poh Chiang

    2016-01-01

    In this paper, a novel communication strategy called Power Talk is introduced to realize the power line communication among the Voltage Source Converters (VSC) of DC MicroGrids (MGs). Each VSC transmits information by changing the control parameters, and receives information by observing the local...... output power. By using common coding schemes, which transform the DC MGs in some familiar communication channels, some important communication challenges can be addressed, such as random load variations and VSCs switching, as it do not need a separate communication channel. For this purpose, two multiple...

  2. Power Preservation

    DEFF Research Database (Denmark)

    Galster, Kjeld

    Power Preservation (Abstract) In the 17th century, just as today, coalitions needed ‘lead nations’. This was assumed to be a power with great military and economic potentials, and Denmark endeavoured to act as such a leader in the Thirty Years War from 1626 to 28. The results were not encouraging...... in the military field and they were disastrous as far as fiscal matters were concerned. Sweden took over the leadership of the protestant side and she took over Denmark’s place amongst the great powers of the Baltic Region. From that time onwards, Danish influence and options on the international stage gradually...... declined. Thus, Denmark of the 17th century is not to be counted amongst the great powers, but since Christian V’s accession to the throne in 1670 Denmark-Norway has developed into one of Europe’s most highly militarised states. Apart from a permanently combat ready navy, the country maintains a standing...

  3. 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

  4. High Power Factor Power Design

    Directory of Open Access Journals (Sweden)

    Zhang Jing-yi

    2013-07-01

    Full Text Available The PFC circuit takes UCC28019 made by TI Company as the core of system control, realize the power factor correction circuit functions, and the circuit power factor can be measured. Through a variety of detection circuit, with the support SCM control. And 30V~36V output voltage regulator can be set; with over-current protection circuits function, and be able to automatically back. Output current, voltage, and little significant value are displayed by display modules.

  5. EphrinA/EphA-induced ectodomain shedding of neural cell adhesion molecule regulates growth cone repulsion through ADAM10 metalloprotease.

    Science.gov (United States)

    Brennaman, Leann H; Moss, Marcia L; Maness, Patricia F

    2014-01-01

    EphrinA/EphA-dependent axon repulsion is crucial for synaptic targeting in developing neurons but downstream molecular mechanisms remain obscure. Here, it is shown that ephrinA5/EphA3 triggers proteolysis of the neural cell adhesion molecule (NCAM) by the metalloprotease a disintegrin and metalloprotease (ADAM)10 to promote growth cone collapse in neurons from mouse neocortex. EphrinA5 induced ADAM10 activity to promote ectodomain shedding of polysialic acid-NCAM in cortical neuron cultures, releasing a ~ 250 kDa soluble fragment consisting of most of its extracellular region. NCAM shedding was dependent on ADAM10 and EphA3 kinase activity as shown in HEK293T cells transfected with dominant negative ADAM10 and kinase-inactive EphA3 (K653R) mutants. Purified ADAM10 cleaved NCAM at a sequence within the E-F loop of the second fibronectin type III domain (Leu(671) -Lys(672) /Ser(673) -Leu(674) ) identified by mass spectrometry. Mutations of NCAM within the ADAM10 cleavage sequence prevented EphA3-induced shedding of NCAM in HEK293T cells. EphrinA5-induced growth cone collapse was dependent on ADAM10 activity, was inhibited in cortical cultures from NCAM null mice, and was rescued by WT but not ADAM10 cleavage site mutants of NCAM. Regulated proteolysis of NCAM through the ephrin5/EphA3/ADAM10 mechanism likely impacts synapse development, and may lead to excess NCAM shedding when disrupted, as implicated in neurodevelopmental disorders such as schizophrenia. PSA-NCAM and ephrinA/EphA3 coordinately regulate inhibitory synapse development. Here, we have found that ephrinA5 stimulates EphA3 kinase and ADAM10 activity to promote PSA-NCAM cleavage at a site in its second FNIII repeat, which regulates ephrinA5-induced growth cone collapse in GABAergic and non-GABAergic neurons. These findings identify a new regulatory mechanism which may contribute to inhibitory connectivity.

  6. Power Down

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Cai Wending and his colleague Xie Changsheng have been living out of a suitcase for the past two months.The pair,managers at a coal-fired power plant in Hunan Province,have been staying in a modest three-star hotel in Jincheng,a small city in Shanxi Province.They are not the only long-term residents of the hotel.Numerous power plant officials have been drawn to Jincheng from across China,all for the same purpose-to buy coal.

  7. Powering up

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    China building the world’s first third-generation nuclear power plants based on American technology Almost 30 years ago, a partial core meltdown occurred in one of the two nuclear reactors at Three Mile llsland Nuclear Generating Station in

  8. Comic Power

    DEFF Research Database (Denmark)

    Tønder, Lars

    2014-01-01

    by skepticism about the enduring contributions of comic acts, and it then goes on to suggest that we turn to an alternative trajectory in democratic theory, one that encourages us to focus on the empowering and pluralizing potential embedded in what I name “comic power.” The wager is that attention...

  9. Power Play

    Institute of Scientific and Technical Information of China (English)

    BRADLEY GARDNER

    2008-01-01

    @@ Bill Emmott's new book,Rivals:How the Power Struggle Between China,India and Japan Will Shape Our Next Decade,is an investigation of the problematic relationship between China,India,and Japan,as two of those countries begin to assert themselves on the world stage,and how the situation could result in all-out conflict.

  10. Power Talk

    DEFF Research Database (Denmark)

    Stefanovic, Cedomir; Popovski, Petar; Angjelichinoski, Marko

    2015-01-01

    , while it is received by processing the bus measurements that units perform. This implies that the communication does not require a dedicated modem, but instead it is piggybacked on top of the power electronics. The communication is challenged by the random fluctuations of the voltage level due...

  11. Power semiconductors

    CERN Document Server

    Kubát, M

    1984-01-01

    The book contains a summary of our knowledge of power semiconductor structures. It presents first a short historic introduction (Chap. I) as well as a brief selection of facts from solid state physics, in particular those related to power semiconductors (Chap. 2). The book deals with diode structures in Chap. 3. In addition to fundamental facts in pn-junction theory, the book covers mainly the important processes of power structures. It describes the emitter efficiency and function of microleaks (shunts). the p +p and n + n junctions, and in particular the recent theory of the pin, pvn and p1tn junctions, whose role appears to be decisive for the forward mode not only of diode structures but also of more complex ones. For power diode structures the reverse mode is the decisive factor in pn-junction breakdown theory. The presentation given here uses engineering features (the multiplication factor M and the experimentally detected laws for the volume and surface of crystals), which condenses the presentation an...

  12. POWER FUNCTIONS

    Institute of Scientific and Technical Information of China (English)

    王雷

    2008-01-01

    <正>A power function of degree n is a function of the form f(x)=ax~n.For large n,it appears that the graph coincide with the x-axis near the origin,but it does not;the graph actually touches the x—axis only at the origin.

  13. Power Shift

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ "We are entering a new era of world history: the end of Western domination and the arrival of the Asian century. The question is: will Washington wake up to this reality?" This is the central premise of Kishore Mahbubani's provocative new book The New Asian Hemisphere: The Irresistible Shift of Global Power to the East.

  14. Power branding

    Energy Technology Data Exchange (ETDEWEB)

    Chambers, A.

    1998-12-31

    For most of its century-long history, electricity was a natural monopoly, due in part to the excessive cost of the necessary infrastructure. In the past decade, however, politics have pushed the industry toward competition and consumer choice. At the same time, technology has been developed that allows consumers to choose their electricity supplier and to track the flow of power through the various grids and lines. In her new book, Power Branding, author and industry expert Ann Chambers examines marketing and branding of electricity -- what it is, how it`s done, what its benefits are for electric utilities, marketers, and even natural gas companies allied with the utilities. She surveys industry leaders who have already taken a dive into the ocean of marketing and offers lessons drawn from their experiences. She also takes a look at other formerly regulated industries -- airlines, telephone, natural gas -- and describes how their rebirth as free-market industries may affect the course of the electric utility industry`s experience. The contents include: Introduction; Basics of branding: Brand image; Value-added services; Southern Company; Duke Energy; UtiliCorp/EnergyOne/Aquila--big and brand; Engage energy; Florida Power and Light Co.; Enron; Convergence; Lessons from the natural gas industry; Lessons from other industries; Conclusion; Resources; Glossary of branding, marketing and Btu convergence; and Major federal legislation affecting the electric power industry.

  15. Poultry power

    Energy Technology Data Exchange (ETDEWEB)

    Loram, G.

    2000-02-01

    This article gives details of the world's largest power plant fired by poultry litter and forestry waste fired in Thetford, UK. The processing of the waste, the injection of the waste by air, the plant operation, and the cleaning of the flue gas are described. The low levels of odour and noise, and the environmental benefits of the plant which produces no methane or carbon dioxide emissions are noted. (uk)

  16. Cyber Power

    Science.gov (United States)

    2010-05-01

    attributed to “patriotic hackers” in Russia who were offended by Estonia’s movement of a World War II monument to Soviet soldiers. In 2008, shortly...internet to mobilize Chinese students to demonstrate against Japan when its officials took positions that offended Chinese views of the 1930s...reduction of power differentials among them. Anyone from a teen age hacker to a major modern government can do damage in cyber space, and as the famous New

  17. Suntech Power

    Institute of Scientific and Technical Information of China (English)

    BRAKLEY GARDNER

    2008-01-01

    @@ Why the new US president could provide a boost for China's largest solar firm Back in the glory days of China investing, Suntech Power (尚德太阳能电力), China's largest solar com-pany, benefited from both inves-tor interest during China's stock market boom, and the growing demand for solar technologies worldwide, as governments be-gan implementing a raft of new measures providing assistance to renewable energy companies.

  18. BRICS Power

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    When Goldman Sachs economist Jim O’Neill coined the acronym BRIC to describe collectively Brazil,Russia,India and China,the world mainly regarded it as one of the easy-come,easy-go terms in economics.A decade later,O’Neill’s concept is not forgotten.It is successfully playing an historic role in representing the shift in global economic power away

  19. Balance of Attraction and Repulsion in Nucleic-Acid Base Stacking: CCSD(T)/Complete-Basis-Set-Limit Calculations on Uracil Dimer and a Comparison with the Force-Field Description

    Energy Technology Data Exchange (ETDEWEB)

    Morgado, Claudio A.; Jurecka, Petr; Svozil, Daniel; Hobza, Pavel; Sponer, Jiri

    2009-06-09

    We have carried out reference quantum-chemical calculations for about 100 geometries of the uracil dimer in stacked conformations. The calculations have been specifically aimed at geometries with unoptimized distances between the monomers including geometries with mutually tilted monomers. Such geometries are characterized by a delicate balance between local steric clashes and local unstacking and had until now not been investigated using reference quantummechanics (QM) methods. Nonparallel stacking geometries often occur in nucleic acids and are of decisive importance, for example, for local conformational variations in B-DNA. Errors in the shortrange repulsion region would have a major impact on potential energy scans which were often used in the past to investigate local geometry variations in DNA. An incorrect description of such geometries may also partially affect molecular dynamics (MD) simulations in applications when quantitative accuracy is required. The reference QM calculations have been carried out using the MP2 method extrapolated to the complete basis-set limit and corrected for higher-order electron-correlation contributions using CCSD(T) calculations with a medium-sized basis set. These reference calculations have been used as benchmark data to test the performance of the DFT-D, SCS(MI)-MP2, and DFTSAPT QM methods and of the AMBER molecular-mechanics (MM) force field. The QM methods show close to quantitative agreement with the reference data, albeit the DFT-D method tends to modestly exaggerate the repulsion of steric clashes. The force field in general also provides a good description of base stacking for the systems studied here. However, for geometries with close interatomic contacts and clashes, the repulsion effects are rather severely exaggerated. The discrepancy reported here should not affect the overall stability of MD simulations and qualitative applications of the force field. However, it may affect the description of subtle

  20. Power optics

    Energy Technology Data Exchange (ETDEWEB)

    Apollonov, V V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2014-02-28

    By using the theory we developed in the early 1970s, a broad range of phenomena is considered for an optical surface of a solid body that is exposed to radiation arbitrarily varying in time and producing temperature fields, thermoelastic stresses and thermal deformations on the surface layer. The examination is based on the relations (which are similar to Duhamel's integral formula from the theory of heat conduction) between the quantities characterising the thermal stress state in any nonstationary regimes of energy input into a solid. A peculiar feature of the analysis of the thermal stress state in this case consists in the fact that this relation comprises time as a parameter, which in turn is a consequence of incoherence of the quasi-stationary problem of thermoelasticity. This phenomenon is particularly important for the optics of high-power, high-pulse repetition rate lasers, which are being actively developed. In the review, we have recently published in Laser Physics, the thermal stress state of a solid is analysed. In this state, time is treated as an independent variable used in differentiation. Such an approach greatly reduces the applicability of the method. The review published contains data on the use of capillary porous structures made of various materials with different degrees of the surface development. Moreover, such structures can be efficiently employed to increase the heat exchange at a temperature below the boiling point of the coolant. In the present review we discuss the dependences of the limiting laser intensities on the duration of a pulse or a pulse train, corresponding to the three stages of the state of the reflecting surface and leading to unacceptable elastic deformations of the surface, to the plastic yield of the material accompanied by the formation of residual stresses and to the melting of the surface layer. We also analyse the problem of heat exchange in the surface layer with a liquid metal coolant pumped through it

  1. Power optics

    Science.gov (United States)

    Apollonov, V. V.

    2014-02-01

    By using the theory we developed in the early 1970s, a broad range of phenomena is considered for an optical surface of a solid body that is exposed to radiation arbitrarily varying in time and producing temperature fields, thermoelastic stresses and thermal deformations on the surface layer. The examination is based on the relations (which are similar to Duhamel's integral formula from the theory of heat conduction) between the quantities characterising the thermal stress state in any nonstationary regimes of energy input into a solid. A peculiar feature of the analysis of the thermal stress state in this case consists in the fact that this relation comprises time as a parameter, which in turn is a consequence of incoherence of the quasi-stationary problem of thermoelasticity. This phenomenon is particularly important for the optics of high-power, high-pulse repetition rate lasers, which are being actively developed. In the review, we have recently published in Laser Physics, the thermal stress state of a solid is analysed. In this state, time is treated as an independent variable used in differentiation. Such an approach greatly reduces the applicability of the method. The review published contains data on the use of capillary porous structures made of various materials with different degrees of the surface development. Moreover, such structures can be efficiently employed to increase the heat exchange at a temperature below the boiling point of the coolant. In the present review we discuss the dependences of the limiting laser intensities on the duration of a pulse or a pulse train, corresponding to the three stages of the state of the reflecting surface and leading to unacceptable elastic deformations of the surface, to the plastic yield of the material accompanied by the formation of residual stresses and to the melting of the surface layer. We also analyse the problem of heat exchange in the surface layer with a liquid metal coolant pumped through it. The

  2. Identification of gas powered motor propulsion group for small unmanned aerial vehicles

    Science.gov (United States)

    Oldziej, Daniel; Walendziuk, Wojciech; Mirek, Karol

    2016-09-01

    The present work aims at the dynamics identification of gas powered motor propulsion applied in remotely piloted aircraft (RPA) of the small or medium class. In subsequent chapters, the criteria indicating the choice of an electric or a gas power system are described. Moreover, the classification and characteristics of gas powered motor propulsions are presented. The main body of the article contains a laboratory stand dedicated to test the fumes from the motor propulsions in order to measure their static and dynamic characteristics. A wireless solution of acquiring the measurement data from the laboratory stand reflecting real working conditions of the repulsion is suggested. In further parts, the dynamics identification is done, and the transfer function of the object is presented.

  3. 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...... electronics is changing from being a minor energy source to be acting as an important power source. By that wind power is also getting an added value....

  4. Power management system

    Science.gov (United States)

    Algrain, Marcelo C.; Johnson, Kris W.; Akasam, Sivaprasad; Hoff, Brian D.

    2007-10-02

    A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

  5. Power Sources for Ultra Low Power Electronics

    Science.gov (United States)

    2000-06-12

    DARPA asked JASON to examine the issue of power sources for low power electronics with a specific emphasis on the properties of nuclear batteries and...integrated power sources combining power and electronics. During the 1998 Summer Study a workshop was held to provide background for the study, with

  6. 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...

  7. Women, Power, and Libraries.

    Science.gov (United States)

    Schuman, Patricia Glass

    1984-01-01

    Discusses the concept of power in the context of women and the library profession, citing views of power by Max Weber, John Kenneth Galbraith, Letty Cottin Pogrebin, and Rosabeth Moss Kantor. Male power and female submission, defining power, organizing for power, and sharing power are highlighted. A 12-item bibliography is included. (EJS)

  8. “十二五”期间城镇供水远传抄表系统应用与发展%Application and development of urban water supply long distance meter reading system during the“twelfth five-year plan”

    Institute of Scientific and Technical Information of China (English)

    刘百德

    2012-01-01

    Based on the introduction of the technical standards and rules, construction and modification for long distance meter reading system, this paper generally analyzed the development of urban long distance meter reading system in recent years. introduced the characteristics and principles of several "directly reading" long distance meter reading system. Combined with the concepts and technologies of "internet of things" and "cloud computing", the developing direction during the "twelfth five-year plan" was brought forward.%在介绍有关远传水表技术规范、标准制定和修订基础上,概要分析了近年城镇供水远传抄表系统的发展情况,介绍了几种“直读”式远传抄表系统的特征原理,结合物联网、云计算的概念和技术,提出在“十二五”期间的发展方向.

  9. Developing Countermeasure of Mining Industry with Tibetan Characteristics in the Twelfth FiveYear Plan Period: Based on the Perspective of Construction of Ecological Tibet%“十二五”时期西藏特色矿产业发展对策研究——基于建设生态西藏的视角

    Institute of Scientific and Technical Information of China (English)

    陈爱东

    2012-01-01

    “十二五”期间,西藏自治区政府明确提出了坚持可持续发展,以构筑重要的生态安全屏障和建设生态西藏为目标.矿产资源作为西藏有战略意义和产业优势的特色产业,必须正确处理生态保护与资源开发的关系,坚持把生态环境承载能力作为发展经济、开发资源的先决条件和基本依据,有序高效利用资源.%In the period of "Twelfth Five-Year Plan", Tibet Autonomous Region government put forward clearly to insist on sustainable development, in order to build the important ecological security barrier and the construction of ecological Tibet as the goal. As mineral resources in Tibet has strategic significance and industrial advantage characteristic industry, we must correctly handle the relationship between ecological protection and resources development, adhere to the ecological environmental carrying capacity as the development of economy, the development of the prerequisite resource and basic basis, orderly and efficient use of resources.

  10. 我国塑料管道行业"十一·五"期间发展概况和"十二·五"期间发展趋势浅析%Review of China Plastics Pipes Industry during the Eleventh Five-year Plan Period and Its Prospect in the Twelfth Five-year Plan Period

    Institute of Scientific and Technical Information of China (English)

    王占杰

    2011-01-01

    This article discussed the development status about the output and export of the domestic plastics pipes industry during the eleventh five-year plan period. The problems of the plastics pipes industry were pointed out. Finally, the development goals and some suggestion of the plastics pipes industry during the twelfth five-year plan period were given.%综述了我国塑料管道行业在"十一·五"期间的发展状况,包括产量及出口情况;简单介绍了塑料管道的应用领域;指出了"十一·五"期间塑料管道行业存在的问题;最后,提出了"十二·五"期间我国塑料管道行业的发展目标,并对今后的发展给出了一些建议.

  11. The Analysis of Acid Rain Characteristics during “Twelfth Five-Year” Period in Songjiang District of Shanghai%上海市松江区“十二五”期间降水的变化特征分析

    Institute of Scientific and Technical Information of China (English)

    周焱

    2016-01-01

    本文通过分析上海市松江区“十二五”期间降水pH值、酸雨频率及化学组分和浓度变化趋势,得出“十二五”期间松江区酸雨由硫酸型向硫酸-硝酸混合型演变的趋势,且降水酸化仍在继续,并对其主要成因进行了分析。建议松江区“十三五”期间在巩固控硫成果的基础上,加大对氮氧化物的控制力度。%In this paper, according to analyzing the acid rain pH, acid rain frequency and the change of the chemical composition and concentration in Songjiang District of Shanghai during“twelfth five-year” period, it is concluded that the acid rain evolved from sulfuric acid type to mixed acid type of nitric acid and sulphuric acid, and the precipitation acidification continuously happened � Also, the main causes of these phenomena were further analysed� Finally, it is suggested to strengthen nitrogen oxide control based on the effect of sulfur control during “thirteenth five-year” period.

  12. 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 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...... renewable energy sources, wind energy, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

  13. 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...... renewable energy sources, wind energy, which by means of power electronics are changing from being minor energy sources to be acting as important power sources in the energy system....

  14. Dynamic power flow controllers

    Science.gov (United States)

    Divan, Deepakraj M.; Prasai, Anish

    2017-03-07

    Dynamic power flow controllers are provided. A dynamic power flow controller may comprise a transformer and a power converter. The power converter is subject to low voltage stresses and not floated at line voltage. In addition, the power converter is rated at a fraction of the total power controlled. A dynamic power flow controller controls both the real and the reactive power flow between two AC sources having the same frequency. A dynamic power flow controller inserts a voltage with controllable magnitude and phase between two AC sources; thereby effecting control of active and reactive power flows between two AC sources.

  15. Power electronics for low power arcjets

    Science.gov (United States)

    Hamley, John A.; Hill, Gerald M.

    1991-01-01

    In anticipation of the needs of future light-weight low-power spacecraft, arcjet power electronics in the 100- to 400-W operating range were developed. Power topologies similar to those in the higher 2-kW and 5- to 30-kW power range were implemented, including a four-transistor bridge-switching circuit, current-mode pulse-width modulated control, and an output current averaging inductor with an integral pulse generation winding. Reduction of switching transients was accomplished using a low inductance power distribution network, and no passive snubber circuits were necessary for power switch protection. Phase shift control of the power bridge was accomplished using an improved pulse width modulation to phase shift converter circuit. These features, along with conservative magnetics designs, allowed power conversion efficiencies of greater than 92.5 percent to be achieved into resistive loads over the entire operating range of the converter.

  16. Hardware Accelerated Power Estimation

    CERN Document Server

    Coburn, Joel; Raghunathan, Anand

    2011-01-01

    In this paper, we present power emulation, a novel design paradigm that utilizes hardware acceleration for the purpose of fast power estimation. Power emulation is based on the observation that the functions necessary for power estimation (power model evaluation, aggregation, etc.) can be implemented as hardware circuits. Therefore, we can enhance any given design with "power estimation hardware", map it to a prototyping platform, and exercise it with any given test stimuli to obtain power consumption estimates. Our empirical studies with industrial designs reveal that power emulation can achieve significant speedups (10X to 500X) over state-of-the-art commercial register-transfer level (RTL) power estimation tools.

  17. 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

  18. Electrical Power Converter

    NARCIS (Netherlands)

    Ferreira, J.A.

    2014-01-01

    Electrical power converter for converting electrical power of a power source connected or connectable at an input to electrical DC-power at an output, wherein between the input and the output a first circuit of submodules is provided, wherein said first circuit of submodules and the power source for

  19. Power flow controller

    NARCIS (Netherlands)

    Ferreira, J.A.; Yuan, Z.; De Haan, S.W.H.

    2008-01-01

    The invention relates to a power flow controller, comprising at least one first converter coupled with a power transmission line, and at least one second converter coupled with a power source, wherein said power source operates at a predeter-mined first frequency and connects to the power transmissi

  20. Wind Power - A Power Source Enabled by Power Electronics

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Chen, Zhe

    2004-01-01

    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 deregul......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 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 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...

  1. 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....

  2. Kansas Power Plants

    Data.gov (United States)

    Kansas Data Access and Support Center — The Kansas Power Plants database depicts, as point features, the locations of the various types of power plant locations in Kansas. The locations of the power plants...

  3. Power and Control in Kathmandu: A Comparison of Attempted Power, Actual Power, and Achieved Power.

    Science.gov (United States)

    Emery, Clifton R; Thapa, Sirjana; Wu, Shali

    2016-05-05

    We argue that the concept of power has been inadvertently sidelined in recent theory and research on husband violence. Three types of relationship power may matter with respect to husband violence: attempted power, actual power, and achieved power. Analyses of a randomly selected representative sample of 270 married or partnered women in Kathmandu showed that actual power was related to husband violence prevalence, severity, and injury. Achieved power was related to husband violence prevalence and severity, and attempted power was related to husband violence injury. Implications are discussed.

  4. Power Service Shops

    Data.gov (United States)

    Federal Laboratory Consortium — TVA's Power Service Shops provides expert repair and maintenance of power system components and large industrial equipment. With world-class maintenance facilities...

  5. 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

  6. 第十二届全运会有效推动社会文明素质全面提升的策略研究%Research of strategies to effectively prompt the comprehensive enhance of the social civilization by Twelfth National Games

    Institute of Scientific and Technical Information of China (English)

    贾文伟

    2013-01-01

      从文化的视角阐述社会文明素质的基本内涵,以辽宁省承办第十二届全运会为契机,探析大型体育赛事对社会文明素质提升的重大作用,从城市理念、民俗文化、文明礼仪、赛场文化、体育旅游、场馆设施和公共体育服务体系等方面提出切实可行、合理有效的大型体育赛事有效推动社会文明素质全面提升的发展策略。为重塑城市新形象,提升举办城市的社会文明发展水平,获取良好的城市文化发展空间提供实践参考。%From a cultural perspective to elaborate the interaction between major sporting events and urban cultural development, by the opportunity of Liaoning Province hosting the Twelfth National Games, to probe the important role of major sporting events to enhance the quality of social civilization, respectively, from the city of philosophy, folk culture, civility, contest culture, sports tourism, sports venues and facilities, and public service system and other aspects, to carry out practical, rational and effective development strategies for major sports events to effectively promote social civilization. Provide practical references to reshape the city's new image, enhance the host city's level of development of social civilization, access to good urban cultural development space.

  7. Human Power Empirically Explored

    NARCIS (Netherlands)

    Jansen, A.J.

    2011-01-01

    Harvesting energy from the users’ muscular power to convert this into electricity is a relatively unknown way to power consumer products. It nevertheless offers surprising opportunities for product designers; human-powered products function independently from regular power infrastructure, are conven

  8. Wind Power Now!

    Science.gov (United States)

    Inglis, David Rittenhouse

    1975-01-01

    The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

  9. Wind Power Now!

    Science.gov (United States)

    Inglis, David Rittenhouse

    1975-01-01

    The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

  10. Distributed Power Flow Controller

    NARCIS (Netherlands)

    Yuan, Z.

    2010-01-01

    In modern power systems, there is a great demand to control the power flow actively. Power flow controlling devices (PFCDs) are required for such purpose, because the power flow over the lines is the nature result of the impedance of each line. Due to the control capabilities of different types of P

  11. Distributed Power Flow Controller

    NARCIS (Netherlands)

    Yuan, Z.

    2010-01-01

    In modern power systems, there is a great demand to control the power flow actively. Power flow controlling devices (PFCDs) are required for such purpose, because the power flow over the lines is the nature result of the impedance of each line. Due to the control capabilities of different types of P

  12. Power oscillation damping controller

    DEFF Research Database (Denmark)

    2012-01-01

    A power oscillation damping controller is provided for a power generation device such as a wind turbine device. The power oscillation damping controller receives an oscillation indicating signal indicative of a power oscillation in an electricity network and provides an oscillation damping control...

  13. Optimal Power Flow with Power Flow Routers

    OpenAIRE

    2016-01-01

    Power flow routing is an emerging control paradigm for the dynamic control of electric power flows. In this paper, we propose a generic model of a power flow router (PFR) and incorporate it into the optimal power flow (OPF) problem. First, a generic PFR architecture is proposed to encapsulate the desired functions of PFRs. Then, the load flow model of PFRs is developed and incorporated into the OPF framework. To pursue global optimality of the non-convex PFR-incorporated OPF (PFR-OPF) problem...

  14. 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

  15. Atmosphere: Power, Critique, Politics

    DEFF Research Database (Denmark)

    Albertsen, Niels

    2016-01-01

    This paper hans three interrelated parts. First, atmosphere is approached through the concept of power. Atmospheres 'grip' us directly or mediate power indirectly by manipulating moods and evoking emotions. How does atmosphere relate to different conceptions of power? Second, atmospheric powers m...... be critiqued. Which conception of critique can be involved? Third, critiquing atmospheric powers can generate political conflict. How does atmospheric disputes relate to conceptions of politics and the political?...

  16. Powering Future Naval Forces

    Science.gov (United States)

    2010-11-01

    Ground Renewable Expeditionary Energy System Bulk Heterojunction Solar Cell 9  Long endurance fuel cell power (26hr flight Nov 2009)  Low noise...Near Mid Long EMRG Solid State Lights for Submarines Power Node Switching Center Perovskite - based Pyroelectrics 3 Power & Energy Technologies...Fuel Power Generation Energy Storage Distribution& Control Power Loads Fuels Chemistry Alternative Fuels Gas Turbine Generators Fuel Cells Aircraft

  17. Mobile Uninterruptible Power Supply

    Science.gov (United States)

    Mears, Robert L.

    1990-01-01

    Proposed mobile unit provides 20 kVA of uninterruptible power. Used with mobile secondary power-distribution centers to provide power to test equipment with minimal cabling, hazards, and obstacles. Wheeled close to test equipment and system being tested so only short cable connections needed. Quickly moved and set up in new location. Uninterruptible power supply intended for tests which data lost or equipment damaged during even transient power failure.

  18. Power in Households: Disentangling Bargaining Power

    NARCIS (Netherlands)

    R. Mabsout (Ramzi); I.P. van 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 fem

  19. Power, stability of power, and creativity

    NARCIS (Netherlands)

    Sligte, Daniel J.; de Dreu, Carsten K. W.; Nijstad, Bernard A.

    2011-01-01

    Power hierarchies are an essential aspect of social organization, create stability and social order, and provide individuals with incentives to climb the hierarchical ladder. Extending previous work on power and creativity, we put forward that this relationship critically depends on both the stabili

  20. Power barges ease Philippines power shortage

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-02-01

    The Navotas barge project has been a cornerstone in helping the Philippines through the power crisis that almost brought the economy to a standstill. Van der Horst`s stake in the project recently reached more than 240 MW with the delivery of the latest of its four power barges. (author)

  1. Green Power Partnership 100 Green Power Users

    Science.gov (United States)

    EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. Partners on this list use green power to meet 100 of their U.S. organization-wide electricity use.

  2. Power and revenge.

    Science.gov (United States)

    Strelan, Peter; Weick, Mario; Vasiljevic, Milica

    2014-09-01

    We took an individual differences approach to explain revenge tendencies in powerholders. Across four experimental studies, chronically powerless individuals sought more revenge than chronically powerful individuals following a high power episode (Studies 1 and 2), when striking a powerful pose (Study 3), and when making a powerful hand gesture (Study 4). This relationship vanished when participants were not exposed to incidental power. A meta-analysis revealed that, relative to a lack of power or a neutral context, exposure to incidental power increased vengeance among the chronically powerless and reduced vengeance among the chronically powerful. These findings add to previous research on relations between power and aggression, and underscore the role of individual differences as a determinant of powerholders' destructive responses.

  3. Dido: Power and Indulgence in Le Roman d’Eneas

    OpenAIRE

    McGregor, Muriel

    2009-01-01

    During the twelfth century, medieval Western Europe experienced a revival of interest in classical literature. Key Greek and Latin texts had been preserved in Rome’s public and private libraries during the collapse of the Roman Empire in the West. In the sixth and seventh centuries, monastic Christian scholars such as Cassiodorus (born ca. 485 AD) and Benedict of Nursia (480 – 547 AD) established scriptoria, places for copying manuscripts, in their monasteries. There they transcribed and stor...

  4. Power Electronics for Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Blaabjerg, Frede

    2016-01-01

    A microgrid (MG) is a stand-alone or grid-connected hybrid renewable system that uses distributed renewable and nonrenewable energy sources and energy storage systems (ESSs) to supply power to local loads. The system is ordinarily based on power electronics, with interface converters allowing...... a continuous supply of power in the presence of variable RES production. This chapter describes some specific features of DC MGs in terms of power architecture, control, and protection. It also reviews several uncommon power electronic interfaces. Regarding control, operation without critical communication...... are explained in this chapter. The chapter concludes with a review of power electronic intensive protection solutions for DC MGs....

  5. Electric power systems

    CERN Document Server

    Weedy, B M; Jenkins, N; Ekanayake, J B; Strbac, G

    2012-01-01

    The definitive textbook for Power Systems students, providing a grounding in essential power system theory while also focusing on practical power engineering applications. Electric Power Systems has been an essential book in power systems engineering for over thirty years. Bringing the content firmly up-to-date whilst still retaining the flavour of Weedy's extremely popular original, this Fifth Edition has been revised by experts Nick Jenkins, Janaka Ekanayake and Goran Strbac. This wide-ranging text still covers all of the fundamental power systems subjects but is now e

  6. Small scale power production

    Energy Technology Data Exchange (ETDEWEB)

    Muoniovaara, M. [IVO International Ltd, Vantaa (Finland)

    1996-12-31

    IVO International is a major constructor of biomass power plants in Finland and abroad. As a subsidiary of Imatran Voima Oy, the largest power utility in Finland, it has designed and constructed ten power plants owned by IVO Group or others capable of burning biomasses. Sizes of the plants vary from the world`s largest condensing peat-fired power plant of 155 MWe to a 6 MWe combined heat and power producing unit. This article describes the biomass power plants designed and constructed by IVO Group 3 refs.

  7. Shipboard electrical power systems

    CERN Document Server

    Patel, Mukund R

    2011-01-01

    Shipboard Electrical Power Systems addresses new developments in this growing field. Focused on the trend toward electrification to power commercial shipping, naval, and passenger vessels, this book helps new or experienced engineers master cutting-edge methods for power system design, control, protection, and economic use of power. Provides Basic Transferable Skills for Managing Electrical Power on Ships or on LandThis groundbreaking book is the first volume of its kind to illustrate optimization of all aspects of shipboard electrical power systems. Applying author Mukund Patel's rare combina

  8. Balancing modern Power System with large scale of wind power

    OpenAIRE

    Basit, Abdul; Altin, Müfit; Hansen, Anca Daniela; Sørensen, Poul Ejnar

    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 s...

  9. Imprisoned in disgust: Roman Polanski's Repulsion

    NARCIS (Netherlands)

    Laine, T.

    2011-01-01

    Noël Carroll has suggested that scary films scare because our emotions are structured by the disgusting and dangerous properties of the films’ monsters. By contrast, this essay argues that some scary films scare through more direct means than can be explained by entertaining in thought, say, the

  10. Coordination Logic for Repulsive Resolution Maneuvers

    Science.gov (United States)

    Narkawicz, Anthony J.; Munoz, Cesar A.; Dutle, Aaron M.

    2016-01-01

    This paper presents an algorithm for determining the direction an aircraft should maneuver in the event of a potential conflict with another aircraft. The algorithm is implicitly coordinated, meaning that with perfectly reliable computations and information, it will in- dependently provide directional information that is guaranteed to be coordinated without any additional information exchange or direct communication. The logic is inspired by the logic of TCAS II, the airborne system designed to reduce the risk of mid-air collisions between aircraft. TCAS II provides pilots with only vertical resolution advice, while the proposed algorithm, using a similar logic, provides implicitly coordinated vertical and horizontal directional advice.

  11. Repulsive force support system feasibility study

    Science.gov (United States)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1987-01-01

    A new concept in magnetic levitation and control is introduced for levitation above a plane. A set of five vertical solenoid magnets mounted flush below the plane supports and controls the model in five degrees of freedom. The compact system of levitation coils is contained in a space 2.4 m (96 in) diameter by 1 m (40 in) deep with the top of the levitation system 0.9 m (36 in) below the center line of the suspended model. The levitated model has a permanent magnet core held in position by the five parallel superconductive solenoids symmetrically located in a circle. The control and positioning system continuously corrects for model position in five dimensions using computer current pulses superimposed on the levitation coil base currents. The conceptual designs include: superconductive and Nd-Fe-B permanent magnet model cores and levitation solenoids of either superconductive, cryoresistive, or room temperature windings.

  12. Technologies. [space power sources

    Science.gov (United States)

    Brandhorst, Henry W., Jr.

    1992-01-01

    Energy technologies to meet the power requirements of future space missions are reviewed. Photovoltaic, solar dynamic, and solar thermal technologies are discussed along with techniques for energy storage and power management and distribution.

  13. Geothermal Power Technologies

    DEFF Research Database (Denmark)

    Montagud, Maria E. Mondejar; Chamorro, C.R.

    2016-01-01

    Although geothermal energy has been widely deployed for direct use in locations with especial geologic manifestations, its potential for power generation has been traditionally underestimated. Recent technology developments in drilling techniques and power conversion technologies from low...

  14. Spacecraft Power Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I project will develop the Spacecraft Power Monitor (SPM) which will use non-intrusive electrical monitoring (NEMO). NEMO transforms the power...

  15. Space Solar Power Program

    Energy Technology Data Exchange (ETDEWEB)

    Arif, H.; Barbosa, H.; Bardet, C.; Baroud, M.; Behar, A.; Berrier, K.; Berthe, P.; Bertrand, R.; Bibyk, I.; Bisson, J.; Bloch, L.; Bobadilla, G.; Bourque, D.; Bush, L.; Carandang, R.; Chiku, T.; Crosby, N.; De Seixas, M.; De Vries, J.; Doll, S.; Dufour, F.; Eckart, P.; Fahey, M.; Fenot, F.; Foeckersperger, S.; Fontaine, J.E.; Fowler, R.; Frey, H.; Fujio, H.; Gasa, J.M.; Gleave, J.; Godoe, J.; Green, I.; Haeberli, R.; Hanada, T.; Ha

    1992-08-01

    Information pertaining to the Space Solar Power Program is presented on energy analysis; markets; overall development plan; organizational plan; environmental and safety issues; power systems; space transportation; space manufacturing, construction, operations; design examples; and finance.

  16. Green Power Markets

    Science.gov (United States)

    The U.S. EPA's Green Power Partnership defines Green power is a subset of renewable energy and represents those renewable energy resources and technologies that provide the highest environmental benefit.

  17. Green Power Communities

    Science.gov (United States)

    GPCs are towns, villages, cities, counties, or tribal governments in which the local government, businesses, and residents collectively use green power in amounts that meet or exceed EPA's Green Power Community purchase requirements.

  18. What Is Green Power?

    Science.gov (United States)

    The U.S. EPA's Green Power Partnership defines Green power is a subset of renewable energy and represents those renewable energy resources and technologies that provide the highest environmental benefit.

  19. Green Power Partner List

    Science.gov (United States)

    The U.S. EPA's Green Power Partnership is a voluntary program designed to reduce the environmental impact of electricity generation by promoting renewable energy. There are thousands of Green Power Partners, all listed on this page.

  20. Soldier System Power Sources

    Science.gov (United States)

    2006-12-31

    squad level, with the fundamental goal of reducing the total mass of the electric power sources carried by a Marine in the Expeditionary Forces while...still meeting all of his electric power demands. To achieve that goal, this work investigated the effectiveness of hybrid power sources composed...variously of batteries, fuel cells, and super capacitors, it developed control algorithms for those hybrid power sources , it assessed the value of

  1. Microwave power engineering applications

    CERN Document Server

    Okress, Ernest C

    2013-01-01

    Microwave Power Engineering, Volume 2: Applications introduces the electronics technology of microwave power and its applications. This technology emphasizes microwave electronics for direct power utilization and transmission purposes. This volume presents the accomplishments with respect to components, systems, and applications and their prevailing limitations in the light of knowledge of the microwave power technology. The applications discussed include the microwave heating and other processes of materials, which utilize the magnetron predominantly. Other applications include microwave ioni

  2. Power Converters for Accelerators

    CERN Document Server

    Visintini, R

    2015-01-01

    Particle accelerators use a great variety of power converters for energizing their sub-systems; while the total number of power converters usually depends on the size of the accelerator or combination of accelerators (including the experimental setup), the characteristics of power converters depend on their loads and on the particle physics requirements: this paper aims to provide an overview of the magnet power converters in use in several facilities worldwide.

  3. Solar mobile power supply

    OpenAIRE

    Hu, Libian

    2014-01-01

    The solar mobile power supply is a comprehensive energy saving and environment protective product. Besides, it consists of solar panels, storage battery and controller as well as other important components. Based on the traditional solar charging circuit, this solar power supply combines the 5V USB interface and 12V adjustable circuit as well as the 220V inverter and power adapter to greatly improve the function of the power system.

  4. Beyond packing of hard spheres: The effects of core softness, non-additivity, intermediate-range repulsion, and many-body interactions on the glass-forming ability of bulk metallic glasses

    Science.gov (United States)

    Zhang, Kai; Fan, Meng; Liu, Yanhui; Schroers, Jan; Shattuck, Mark D.; O'Hern, Corey S.

    2015-11-01

    When a liquid is cooled well below its melting temperature at a rate that exceeds the critical cooling rate Rc, the crystalline state is bypassed and a metastable, amorphous glassy state forms instead. Rc (or the corresponding critical casting thickness dc) characterizes the glass-forming ability (GFA) of each material. While silica is an excellent glass-former with small Rc alloys are typically poor glass-formers with large Rc > 1010 K/s. Only in the past thirty years have bulk metallic glasses (BMGs) been identified with Rc approaching that for silica. Recent simulations have shown that simple, hard-sphere models are able to identify the atomic size ratio and number fraction regime where BMGs exist with critical cooling rates more than 13 orders of magnitude smaller than those for pure metals. However, there are a number of other features of interatomic potentials beyond hard-core interactions. How do these other features affect the glass-forming ability of BMGs? In this manuscript, we perform molecular dynamics simulations to determine how variations in the softness and non-additivity of the repulsive core and form of the interatomic pair potential at intermediate distances affect the GFA of binary alloys. These variations in the interatomic pair potential allow us to introduce geometric frustration and change the crystal phases that compete with glass formation. We also investigate the effect of tuning the strength of the many-body interactions from zero to the full embedded atom model on the GFA for pure metals. We then employ the full embedded atom model for binary BMGs and show that hard-core interactions play the dominant role in setting the GFA of alloys, while other features of the interatomic potential only change the GFA by one to two orders of magnitude. Despite their perturbative effect, understanding the detailed form of the intermetallic potential is important for designing BMGs with cm or greater casting thickness.

  5. The water resources carrying capacity evaluation of Pulandian city during“The national twelfth five-year plan”construction period%普兰店市“十二五”建设期间水资源承载力评价

    Institute of Scientific and Technical Information of China (English)

    洪思扬; 刘欣

    2012-01-01

      In order to full exploit and utilize water resources, optimize the allocation of water resources in Pulandian City, to ensure sustained and stable economic and social development, we conduct the analysis and evaluation of present situation of water resources in Pulandian city and the carrying capacity of water resources during “The national twelfth five-year plan” period in Pulandian City. The results reflect an increasingly prominent con-tradiction between supply and demand. According to the actual condition of Pulandian city and the speed of economic develop-ment, we should try to exploit the existing potential of water conservancy, broaden sources of water resources and reduce expenditure simultaneously, draw up water resources planning with the principle of full consideration of urban and rural life, produc-tion, ecological water usage, to solve the contradiction of water resources supply and demand in urban and rural areas.%  为了更好的开发和利用水资源、优化水资源配置,确保普兰店市经济社会持续稳定的发展,我们对普兰店市水资源现状及“十二五”期间水资源承载能力进行了分析评价,评价结果反映出普兰店市水资源日益突出的供需矛盾。根据普兰店市的实际情况与经济发展速度,应尽量挖掘现有水源工程的潜力,开源节流并举,以充分考虑城乡生活、生产、生态用水的原则下,进行水资源配置规划,以解决城乡水资源供需矛盾。

  6. ASPECTOS LESIONALES MICROSCÓPICOS EN HÍGADOS DE SALMONÍDEOS, PROVENIENTES DE CENTROS DE CULTIVO DE LA Xª A XIIª REGIÓN DE CHILE (1988-1998. MICROSCOPIC LESIONS IN SALMONIDS' LIVERS COMING FROM FARM FISH IN THE TENTH TO TWELFTH REGION OF CHILE (1988-1998

    Directory of Open Access Journals (Sweden)

    V. CUBILLOS

    2001-01-01

    Full Text Available El propósito del presente estudio fue determinar los tipos de lesiones microscópicas en hígados de salmonídeos provenientes de centros de cultivo de la Xª a XIIª Región de Chile en el período 1988-1998. Se seleccionaron cortes histológicos de muestras hepáticas correspondientes a 160 salmones coho (O. kisutch, 92 salmones del Atlántico (S. salar, 13 salmones chinook (O. tschawytscha y 90 truchas arcoiris (O. mykiss. Dichas muestras fueron obtenidas aleatoriamente a fin de determinar la localización de las lesiones en el parénquima, de acuerdo a la teoría de Rappaport (1973. \tAl relacionar los trastornos hepáticos (del crecimiento, circulatorios, degenerativos, inflamatorios y necróticos con su localización en el parénquima, llamó la atención que la mayoría de ellos presentaron localización difusa, acompañada en algunos casos de una segunda localización (periportal, mediozonal o centrolobulillar. En el caso de infiltrado linfoblástico, la localización de las células fue predominantemente periportalThe purpose of this report is to determine the kinds of microscopic lesions present in livers of salmonids grown in fish farms in the Tenth to Twelfth Region, from 1988 until 1998. Selected histological samples corresponding to 160 coho salmons (O. kisutch, 92 Atlantic salmons (S. salar, 13 chinook salmons (O. tschawytscha and 90 rainbow trouts (O. mykiss were observed in order to determine the localization of injuries in the liver parenchyma in the Animal Pathology Institute of the Veterinary Science Faculty. The kinds of pathologies found were classified in relation to their localisation in liver tissue according to the theory of Rappaport (1973 about the microcirculatory hepatic unit. The results of this research indicate that from the total amount of liver samples, the parenchyma localisation of the lesions, when connected to liver disorders (of growth, circulatory, infectious, degenerative, inflammatory and necrotic were

  7. NB Power`s fish handling facilities

    Energy Technology Data Exchange (ETDEWEB)

    Hickman, C. N. [New Brunswick Power, Fredericton, NB (Canada)

    1995-12-31

    Fish handling facilities at the various hydroelectric power generating stations of New Brunswick Power on the St. John River, were described. The facilities described included the fish hoist at the Beechwood Generating Station , the fish ladder at the Tobique Generating Station and a trap and truck operation at the Mactaquac Station. Details of operating arrangements were provided. Operating issues, solutions and ongoing efforts to improve operations further, were discussed. 4 refs., 4 figs.

  8. The Pervasive Power of PowerPoint

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis

    2013-01-01

    allows identification of three distinct PowerPoint subgenres, which differ in how they adapt to the function of project documentation. This paper contributes to organization studies by specifying the boundary conditions under which a genre of professional communication such as PowerPoint can be expected...... to maintain its genre-inherent characteristics even in the face of contradictory organizational requirements and to impose these characteristics on a neighboring domain of organizational communication practices...

  9. Leadership and power

    Directory of Open Access Journals (Sweden)

    V. Kessler

    2010-07-01

    Full Text Available Leadership does not exist without power. Thus we have to reflect on power in order to lay a theoretical foundation for responsible leadership. This interdisciplinary article collects insights from the disciplines of theology, sociology, and crosscultural management. It provides a concise summary of what a Christian leader should know about power in order to use his/her power in an adequate way. The theological reflection reminds us of the fact that, according to the Judeo-Christian tradition, God gave power to humankind (Guardini, 1998. Two opposite dangers are described in this article, namely the abuse of power on the one hand and the misconception of powerlessness as a Christian virtue on the other hand. The sociological section describes different forms of power. Following French and Raven (1960, it introduces seven power bases, which are illustrated by examples from society and the church. The next section describes the different cultural perceptions on power. It shows how the cultural parameter of power distance may influence the appropriate leadership style (Hofstede & Hofstede, 2005. It is argued that our understanding of a right or wrong use of power is strongly influenced by the culture in which we grew up. The article concludes with a list of ethical guidelines on the use of power for responsible Christian leaders.

  10. Aircraft Electric Secondary Power

    Science.gov (United States)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  11. Militarized Thermoelectric Power Sources.

    Science.gov (United States)

    1979-07-01

    Thermoelectric power sources are being developed to provide multifuel, silent, maintenance free tactical power generators for forward area...applications. Recent technology improvements, state of development, and performance characteristics of the 100-Watt and 500-Watt Thermoelectric Power Sources are presented. (Author)

  12. Optical cycle power meter

    DEFF Research Database (Denmark)

    2014-01-01

    A bicycle power meter for measuring power generated when riding a bicycle, the power meter comprising a position-sensitive radiation detector (409) attachable to a component of a crank set (404) of bicycle, and a radiation source (408) attachable to the component of the crank set and configured...

  13. Power Plant Cycling Costs

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N.; Besuner, P.; Lefton, S.; Agan, D.; Hilleman, D.

    2012-07-01

    This report provides a detailed review of the most up to date data available on power plant cycling costs. The primary objective of this report is to increase awareness of power plant cycling cost, the use of these costs in renewable integration studies and to stimulate debate between policymakers, system dispatchers, plant personnel and power utilities.

  14. Nuclear Power in China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China’s vigorous efforts to propel development of nuclear power are paying off as the country’s nuclear power sector advances at an amazing pace. At present, China has set up three enormous nuclear power bases, one each in Qinshan of Zhejiang Province, Dayawan of Guangdong

  15. Power to the People

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Restoring power grids damaged by recent heavy snows is a massive task in the short term and large-scale overhauls of the system could take three to five years Through the mobilization of over 300,000 power company employees, service for 90 percent of the 36,740 power lines damaged by heavy January and February snows has been restored.

  16. The Administrative Power Grab

    Science.gov (United States)

    Sorenson, Richard D.

    2007-01-01

    Administrative power for some school teachers can be an aphrodisiac that can be applied negatively, especially when a leader has devastating instinct for the weaknesses of others. A leader's intellect and heart closes shop and ceases to function when drunk on power. In this article, the author describes how the use of administrative power can be…

  17. The Power of Powerlessness.

    Science.gov (United States)

    Weeks, Gerald; Johnson, Jackie

    1980-01-01

    Power and the paradox of powerlessness are defined in terms of the resource exchange theory of Foa and Foa. Power is conceptualized as the possession of resources, e.g., love, status, and money. The Karpman triangle is used to illustrate the power behind the victim's powerlessness. (Author)

  18. Optimization in power systems

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Geraldo R.M. da [Sao Paulo Univ., Sao Carlos, SP (Brazil). Escola de Engenharia

    1994-12-31

    This paper discusses, partially, the advantages and the disadvantages of the optimal power flow. It shows some of the difficulties of implementation and proposes solutions. An analysis is made comparing the power flow, BIGPOWER/CESP, and the optimal power flow, FPO/SEL, developed by the author, when applied to the CEPEL-ELETRONORTE and CESP systems. (author) 8 refs., 5 tabs.

  19. Wind power soars

    Energy Technology Data Exchange (ETDEWEB)

    Flavin, C. [Worldwatch Inst., Washington, DC (United States)

    1996-12-31

    Opinions on the world market for wind power are presented in this paper. Some data for global wind power generating capacity are provided. European and other markets are discussed individually. Estimated potential for wind power is given for a number of countries. 3 figs.

  20. Power distribution arrangement

    DEFF Research Database (Denmark)

    2010-01-01

    An arrangement and a method for distributing power supplied by a power source to two or more of loads (e.g., electrical vehicular systems) is disclosed, where a representation of the power taken by a particular one of the loads from the source is measured. The measured representation of the amount...