Dynamics of moduli and gaugino condensates in an expanding universe
International Nuclear Information System (INIS)
Papineau, C.; Ramos-Sanchez, S.; Postma, M.
2009-08-01
We study dynamical moduli stabilization driven by gaugino condensation in supergravity. In the presence of background radiation, there exists a region of initial conditions leading to successful stabilization. We point out that most of the allowed region corresponds to initial Hubble rate H close to the scale of condensation Λ, which is the natural cutoff of the effective theory. We first show that including the condensate dynamics sets a strong bound on the initial conditions. We then find that (complete) decoupling of the condensate happens at H about two orders of magnitude below Λ. This bound implies that in the usual scenario with the condensate integrated out, only the vicinity of the minimum leads to stabilization. Finally, we discuss the effects of thermal corrections. (orig.)
The Dynamics of Aerosols in Condensational Scrubbers
DEFF Research Database (Denmark)
Johannessen, Jens Tue; Christensen, Jan A.; Simonsen, Ole
1997-01-01
A mathematical model for the simulation of the dynamics of aerosol change in condensational scrubbers and scrubbing condensers is proposed. The model is applicable for packed column gas/liquid contact when plug flow can be assumed. The model is compared with experimental data for particle removal...... in a pilot plant condensational scrubber. The model can satisfactorily predict particle growth and particle deposition by diffusional, convective and inertial mechanisms for a wide range of conditions. The parameters of principal importance for the model precision are identified and a procedure...
Temporal dynamics of Bose-condensed gases
Energy Technology Data Exchange (ETDEWEB)
Trujillo Martinez, Mauricio
2014-03-19
We perform a detailed quantum dynamical study of non-equilibrium trapped, interacting Bose-condensed gases. We investigate Josephson oscillations between interacting Bose-Einstein condensates confined in a finite size double-well trap and the non-trivial time evolution of a coherent state placed at the center of a two dimensional optical lattice. For the Josephson oscillations three time scales appear. We find that Josephson junction can sustain multiple undamped oscillations up to a characteristic time scale τ{sub c} without exciting atoms out of the condensates. Beyond the characteristic time scale τ{sub c} the dynamics of the junction are governed by fast, non-condensed particles assisted Josephson tunnelling as well as the collisions between non-condensed particles. In the non-condensed particles dominated regime we observe strong damping of the oscillations due to inelastic collisions, equilibrating the system leading to an effective loss of details of the initial conditions. In addition, we predict that an initially self-trapped BEC state will be destroyed by these fast dynamics. The time evolution of a coherent state released at the center of a two dimensional optical lattice shows a ballistic expansion with a decreasing expansion velocity for increasing two-body interactions strength and particle number. Additionally, we predict that if the two-body interactions strength exceeds a certain value, a forerunner splits up from the expanding coherent state. We also observe that this system, which is prepared far from equilibrium, can evolve to a quasistationary non-equilibrium state.
Simulating coronal condensation dynamics in 3D
Moschou, S. P.; Keppens, R.; Xia, C.; Fang, X.
2015-12-01
We present numerical simulations in 3D settings where coronal rain phenomena take place in a magnetic configuration of a quadrupolar arcade system. Our simulation is a magnetohydrodynamic simulation including anisotropic thermal conduction, optically thin radiative losses, and parametrised heating as main thermodynamical features to construct a realistic arcade configuration from chromospheric to coronal heights. The plasma evaporation from chromospheric and transition region heights eventually causes localised runaway condensation events and we witness the formation of plasma blobs due to thermal instability, that evolve dynamically in the heated arcade part and move gradually downwards due to interchange type dynamics. Unlike earlier 2.5D simulations, in this case there is no large scale prominence formation observed, but a continuous coronal rain develops which shows clear indications of Rayleigh-Taylor or interchange instability, that causes the denser plasma located above the transition region to fall down, as the system moves towards a more stable state. Linear stability analysis is used in the non-linear regime for gaining insight and giving a prediction of the system's evolution. After the plasma blobs descend through interchange, they follow the magnetic field topology more closely in the lower coronal regions, where they are guided by the magnetic dips.
Competition between Bose-Einstein Condensation and Spin Dynamics.
Naylor, B; Brewczyk, M; Gajda, M; Gorceix, O; Maréchal, E; Vernac, L; Laburthe-Tolra, B
2016-10-28
We study the impact of spin-exchange collisions on the dynamics of Bose-Einstein condensation by rapidly cooling a chromium multicomponent Bose gas. Despite relatively strong spin-dependent interactions, the critical temperature for Bose-Einstein condensation is reached before the spin degrees of freedom fully thermalize. The increase in density due to Bose-Einstein condensation then triggers spin dynamics, hampering the formation of condensates in spin-excited states. Small metastable spinor condensates are, nevertheless, produced, and they manifest in strong spin fluctuations.
Pion condensation and neutron star dynamics
International Nuclear Information System (INIS)
Kaempfer, B.
1983-01-01
The question of formation of pion condensate via a phase transition in nuclear matter, especially in the core of neutron stars is reviewed. The possible mechanisms and the theoretical restrictions of pion condensation are summarized. The effects of ultradense equation of state and density jumps on the possible condensation phase transition are investigated. The possibilities of observation of condensation process are described. (D.Gy.)
Condensation and Wetting Dynamics on Micro/Nano-Structured Surfaces
Olceroglu, Emre
Because of their adjustable wetting characteristics, micro/nanostructured surfaces are attractive for the enhancement of phase-change heat transfer where liquid-solid-vapor interactions are important. Condensation, evaporation, and boiling processes are traditionally used in a variety of applications including water harvesting, desalination, industrial power generation, HVAC, and thermal management systems. Although they have been studied by numerous researchers, there is currently a lack of understanding of the underlying mechanisms by which structured surfaces improve heat transfer during phase-change. This PhD dissertation focuses on condensation onto engineered surfaces including fabrication aspect, the physics of phase-change, and the operational limitations of engineered surfaces. While superhydrophobic condensation has been shown to produce high heat transfer rates, several critical issues remain in the field. These include surface manufacturability, heat transfer coefficient measurement limitations at low heat fluxes, failure due to surface flooding at high supersaturations, insufficient modeling of droplet growth rates, and the inherent issues associated with maintenance of non-wetted surface structures. Each of these issues is investigated in this thesis, leading to several contributions to the field of condensation on engineered surfaces. A variety of engineered surfaces have been fabricated and characterized, including nanostructured and hierarchically-structured superhydrophobic surfaces. The Tobacco mosaic virus (TMV) is used here as a biological template for the fabrication of nickel nanostructures, which are subsequently functionalized to achieve superhydrophobicity. This technique is simple and sustainable, and requires no applied heat or external power, thus making it easily extendable to a variety of common heat transfer materials and complex geometries. To measure heat transfer rates during superhydrophobic condensation in the presence of non-condensable
Model for dynamical chiral symmetry breaking and quark condensate
International Nuclear Information System (INIS)
Nekrasov, M.L.; Rochev, V.E.
1986-01-01
In the framework of the model, proposed earlier to describe nonperturbative QCD, the singularity of the type 1/k 4 in the gluon propagator is shown to result in dynamical chiral symmetry breaking and appearance of quark condensate. The value, obtained for quark condensate, is close to the phenomenological one
Ultrafast Dynamics of Chemical Reactions in Condensed Phase ...
Indian Academy of Sciences (India)
Ultrafast Dynamics of Chemical Reactions in Condensed Phase: Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond. Dipak K. Palit Radaition & Photochemistry Division Bhabha Atomic Research Centre Mumbai 400 085, India.
International Nuclear Information System (INIS)
Andrieux, M.B.
1984-01-01
Characteristics of the condenser cooling waters of various French 900 MW nuclear power plants. Design and description of various types of condensers: condensers feeded directly with river water, condensers feeded by cooling towers, condensers feeded with sea water of brackish water. Presentation of the main problems encountered with the brass bundles (ammoniacal corrosion, erosion of the peripheral tubes, vibrations of the tubes), with the titanium bundles, with the tubular plates, the tubes-tubular plates assemblies, the coatings of the condenser water chamber (sea water), the vapor by-pass and with the air inlet. Analysis of the in service performances such as condensation pressure, oxygen content and availability [fr
Classification of quench-dynamical behaviors in spinor condensates
Daǧ, Ceren B.; Wang, Sheng-Tao; Duan, L.-M.
2018-02-01
Thermalization of isolated quantum systems is a long-standing fundamental problem where different mechanisms are proposed over time. We contribute to this discussion by classifying the diverse quench-dynamical behaviors of spin-1 Bose-Einstein condensates, which includes well-defined quantum collapse and revivals, thermalization, and certain special cases. These special cases are either nonthermal equilibration with no revival but a collapse even though the system has finite degrees of freedom or no equilibration with no collapse and revival. Given that some integrable systems are already shown to demonstrate the weak form of eigenstate thermalization hypothesis (ETH), we determine the regions where ETH holds and fails in this integrable isolated quantum system. The reason behind both thermalizing and nonthermalizing behaviors in the same model under different initial conditions is linked to the discussion of "rare" nonthermal states existing in the spectrum. We also propose a method to predict the collapse and revival time scales and find how they scale with the number of particles in the condensate. We use a sudden quench to drive the system to nonequilibrium and hence the theoretical predictions given in this paper can be probed in experiments.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
Energy Technology Data Exchange (ETDEWEB)
Gasenzer, Thomas [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); ExtreMe Matter Institute EMMI, GSI, Planckstraße 1, D-64291 Darmstadt (Germany); McLerran, Larry [Physics Department, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Physics Department, China Central Normal University, Wuhan (China); Pawlowski, Jan M.; Sexty, Dénes [Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg (Germany); ExtreMe Matter Institute EMMI, GSI, Planckstraße 1, D-64291 Darmstadt (Germany)
2014-10-15
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates.
Gauge turbulence, topological defect dynamics, and condensation in Higgs models
International Nuclear Information System (INIS)
Gasenzer, Thomas; McLerran, Larry; Pawlowski, Jan M.; Sexty, Dénes
2014-01-01
The real-time dynamics of topological defects and turbulent configurations of gauge fields for electric and magnetic confinement are studied numerically within a 2+1D Abelian Higgs model. It is shown that confinement is appearing in such systems equilibrating after a strong initial quench such as the overpopulation of the infrared modes. While the final equilibrium state does not support confinement, metastable vortex defect configurations appearing in the gauge field are found to be closely related to the appearance of physically observable confined electric and magnetic charges. These phenomena are seen to be intimately related to the approach of a non-thermal fixed point of the far-from-equilibrium dynamical evolution, signaled by universal scaling in the gauge-invariant correlation function of the Higgs field. Even when the parameters of the Higgs action do not support condensate formation in the vacuum, during this approach, transient Higgs condensation is observed. We discuss implications of these results for the far-from-equilibrium dynamics of Yang–Mills fields and potential mechanisms of how confinement and condensation in non-Abelian gauge fields can be understood in terms of the dynamics of Higgs models. These suggest that there is an interesting new class of dynamics of strong coherent turbulent gauge fields with condensates
Stochastic dynamics of a trapped Bose-Einstein condensate
Duine, R.A.; Stoof, H.T.C.
2001-01-01
We present a variational solution of the Langevin field equation describing the nonequilibrium dynamics of a harmonically trapped Bose-Einstein condensate. If the thermal cloud remains in equilibrium at all times, we find that the equations of motion for the parameters in our variational ansatz are
Classical Dynamics of Excitations of Bose Condensates in Anisotropic Traps
Graham, Robert
This lecture discusses some aspects of the dynamics of the collective and single-particle excitations at zero temperature of Bose-Einstein condensates of alkali-vapors in magnetic traps. We shall discuss those aspects which can be understood by taking the short-wavelength or 'eikonal' limit of the excitations. Trapped Bose-Einstein condensates can be excited experimentally either directly via periodic modulations of the trap potential or by scattering light off the condensate. My discussion here will closely follow some theoretical work published in [1-3] that has recently been done in collaboration with Andras Csordas and Peter Szepfalusy at the Research Institute for solid State Physics and Optics in Budapest, Hungary and with Martin Fliesser at the University of Essen, Germany.
Modeling non-adiabatic photoexcited reaction dynamics in condensed phases
International Nuclear Information System (INIS)
Coker, D.F.
2003-01-01
Reactions of photoexcited molecules, ions, and radicals in condensed phase environments involve non-adiabatic dynamics over coupled electronic surfaces. We focus on how local environmental symmetries can effect non-adiabatic coupling between excited electronic states and thus influence, in a possibly controllable way, the outcome of photo-excited reactions. Semi-classical and mixed quantum-classical non-adiabatic molecular dynamics methods, together with semi-empirical excited state potentials are used to probe the dynamical mixing of electronic states in different environments from molecular clusters, to simple liquids and solids, and photo-excited reactions in complex reaction environments such as zeolites
Ultrafast Dynamics of Chemical Reactions in Condensed Phase ...
Indian Academy of Sciences (India)
Ultrafast Dynamics of Chemical Reactions in Condensed Phase: Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond · PowerPoint Presentation · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19.
Inflation via Gravitino Condensation in Dynamically Broken Supergravity
Alexandre, Jean; Mavromatos, Nick E
2015-01-01
Gravitino-condensate-induced inflation via the super-Higgs effect is a UV-motivated scenario for both inflating the early universe and breaking local supersymmetry dynamically, entirely independent of any coupling to external matter. As an added benefit, this also removes the (as of yet unobserved) massless Goldstino associated to global supersymmetry breaking from the particle spectrum. In this review we detail the pertinent properties and outline previously hidden details of the various steps required in this context in order to make contact with current inflationary phenomenology. The class of models of SUGRA we use to exemplify our approach are minimal four-dimensional N=1 supergravity and conformal extensions thereof (with broken conformal symmetry). Therein, the gravitino condensate itself can play the role of the inflaton, however the requirement of slow-roll necessitates unnaturally large values of the wave-function renormalisation. Nevertheless, there is an alternative scenario that may provide Staro...
International Symposium on Dynamics of Ordering Processes in Condensed Matter
Furukawa, H
1988-01-01
The International Symposium on Dynamics of Ordering Processes in Condensed Matter was held at the Kansai Seminar House, Kyoto, for four days, from 27 to 30 August 1987, under the auspices of the Physical Soci ety of Japan. The symposium was financially supported by the four orga nizations and 45 companies listed on other pages in this volume. We are very grateful to all of them and particularly to the greatest sponsor, the Commemorative Association for the Japan World Exposition 1970. A total Df 22 invited lectures and 48 poster presentations were given and 110 participants attended from seven nations. An objective of the Symposium was to review and extend our present understanding of the dynamics of ordering processes in condensed matters, (for example, alloys, polymers and fluids), that are brought to an un stable state by sudden change of such external parameters as temperature and pressure. A second objective, no less important, was to identify new fields of science that might be investigated by sim...
Dynamics of Low-Energy Electron Induced Reactions in Condensed
Boyer, Michael; Soe, Chanmyaemyae; Chamberlain, Kristal; Shyur, Yomay; Arumainayagam, Christopher
2011-03-01
We present insights into the dynamics of low-energy electron-induced reactions in thin films of methanol (CH3 OH). Low-energy electrons in matter can initiate chemical reactions though electron impact ionization of a molecule, electron impact excitation of a molecule, or through dissociation of a transient negative ion formed by electron attachment to a molecule. Our studies focus on the dynamics by which low-energy electron interaction with condensed methanol initiates chemical reactions which lead to the formation of methoxymethanol (CH3 O CH2 OH) and ethylene glycol (HO CH2 CH2 OH). The results of our post-irradiation temperature programmed desorption experiments indicate that both products can form from irradiating methanol with electrons at subionization energies. In addition, we find evidence that dissociative electron attachment plays a role in the formation of methoxymethanol but not in ethylene glycol.
Wang, Kai; Hu, Tao; Hassabou, Abdel H.; Spinnler, Markus; Polifke, Wolfgang
2013-01-01
Condensers serve as important components for humidification-dehumidification (HDH) desalination plants. Based on the interpenetration continua approach with volume averaging technique, a mathematical dynamic model for analyzing the heat and mass transfer within direct contact condensers with co-current or countercurrent flow arrangement was developed. It was validated against the experimental data from a small scale HDH desalination system. Comparisons including the productivities and the temperature profiles of gas, liquid, and solid phases show good agreement with the measurements. Phase change material (PCM) melting processes have little effect on water production rate for co-current flow arrangement, but the condenser packed with PCM capsules have higher water production rates than that packed with air capsules packed under given conditions. The relative humidity profile of the bulk gas shows contrary trend with the gas temperature profile. The direct contact condenser with countercurrent flow arrangement can provide much better heat and mass transfer between gas and water and produce about 16.3% more fresh water than the same condenser with co-current flow arrangement in 4 h under given conditions.
Collapsing dynamics of attractive Bose-Einstein condensates
DEFF Research Database (Denmark)
Bergé, L.; Juul Rasmussen, J.
2002-01-01
The self-similar collapse of 3D and quasi-2D atom condensates with negative scattering length is examined. 3D condensates are shown to blow up following the scenario of weak collapse, for which 3-body recombination weakly dissipates the atoms. In contrast, 2D condensates undergo a strong collapse...
Dynamical pion production via parametric resonance from disoriented chiral condensates
Hiro-Oka, Hideaki; Minakata, Hisakazu
2000-04-01
We discuss a dynamical mechanism of pion production from disoriented chiral condensates. It leads to an explosive production of pions via the parametric resonance mechanism, which is similar to the reheating mechanism in inflationary cosmology. Classically it is related with the instability in the solutions of the Mathieu equation and we explore the quantum aspects of the mechanism. We show that nonlinearities and back reactions can be ignorable for a sufficiently long time under the small amplitude approximations of background σ oscillations, which may be appropriate for the late stage of a nonequilibrium phase transition. It allows us to obtain an explicit quantum state of the produced pions and σ, the squeezed state of BCS type. Single particle distributions and two pion correlation functions are computed within these approximations. The results obtained illuminate the characteristic features of multipion states produced through the parametric amplification mechanism. In particular, two pion correlations of various charge combinations contain back-to-back correlations which cannot be masked by the identical particle interference effect. We suggest that the parametric resonance mechanism might be a cause of the long lasting amplification of low-momentum modes in linear sigma model simulations.
Coherent inflationary dynamics for Bose-Einstein condensates crossing a quantum critical point
Feng, Lei; Clark, Logan W.; Gaj, Anita; Chin, Cheng
2017-12-01
Quantum phase transitions, transitions between many-body ground states, are of extensive interest in research ranging from condensed-matter physics to cosmology1-4. Key features of the phase transitions include a stage with rapidly growing new order, called inflation in cosmology5, followed by the formation of topological defects6-8. How inflation is initiated and evolves into topological defects remains a hot topic of debate. Ultracold atomic gas offers a pristine and tunable platform to investigate quantum critical dynamics9-21. We report the observation of coherent inflationary dynamics across a quantum critical point in driven Bose-Einstein condensates. The inflation manifests in the exponential growth of density waves and populations in well-resolved momentum states. After the inflation stage, extended coherent dynamics is evident in both real and momentum space. We present an intuitive description of the quantum critical dynamics in our system and demonstrate the essential role of phase fluctuations in the formation of topological defects.
Control for dynamics of two coupled Bose-Einstein condensate solitons by potential deviation
Energy Technology Data Exchange (ETDEWEB)
Li Hong [Department of Physics, Hubei Normal University, Huangshi (China); School of Mechanical and Electronic Engineering, Huangshi Institute of Technology, Huangshi (China)], E-mail: lihong-hust@hust.edu.cn; Wang, D.N. [Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong (China)
2008-06-15
The control of the potential deviation for two coupled Bose-Einstein condensate solitons is investigated by the variational approach, and the effects of the potential deviation on dynamics of the two Bose-Einstein condensate solitons are discussed. The potential deviation resets the stationary state, affects the existence time, and changes the switching and self-trapping effect on the Bose-Einstein condensate solitons. The results are confirmed by the evolution of the atom population transferring ratio, and demonstrate a new way to guide the motion of the two Bose-Einstein condensate solitons.
Sakowski, Barbara; Edwards, Daryl; Dickens, Kevin
2014-01-01
Modeling droplet condensation via CFD codes can be very tedious, time consuming, and inaccurate. CFD codes may be tedious and time consuming in terms of using Lagrangian particle tracking approaches or particle sizing bins. Also since many codes ignore conduction through the droplet and or the degradating effect of heat and mass transfer if noncondensible species are present, the solutions may be inaccurate. The modeling of a condensing spray chamber where the significant size of the water droplets and the time and distance these droplets take to fall, can make the effect of droplet conduction a physical factor that needs to be considered in the model. Furthermore the presence of even a relatively small amount of noncondensible has been shown to reduce the amount of condensation [Ref 1]. It is desirable then to create a modeling tool that addresses these issues. The path taken to create such a tool is illustrated. The application of this tool and subsequent results are based on the spray chamber in the Spacecraft Propulsion Research Facility (B2) located at NASA's Plum Brook Station that tested an RL-10 engine. The platform upon which the condensation physics is modeled is SINDAFLUINT. The use of SINDAFLUINT enables the ability to model various aspects of the entire testing facility, including the rocket exhaust duct flow and heat transfer to the exhaust duct wall. The ejector pumping system of the spray chamber is also easily implemented via SINDAFLUINT. The goal is to create a transient one dimensional flow and heat transfer model beginning at the rocket, continuing through the condensing spray chamber, and finally ending with the ejector pumping system. However the model of the condensing spray chamber may be run independently of the rocket and ejector systems detail, with only appropriate mass flow boundary conditions placed at the entrance and exit of the condensing spray chamber model. The model of the condensing spray chamber takes into account droplet
Prethermalization in the cooling dynamics of an impurity in a Bose-Einstein condensate
Lausch, Tobias; Widera, Artur; Fleischhauer, Michael
2018-02-01
We discuss the cooling dynamics of heavy impurity atoms in a Bose-Einstein condensate (BEC) by emission of Cherenkov phonons from scattering with the condensate. In a weakly interacting low-temperature condensate, different scattering processes result in a separation of time scales of the thermalization dynamics. Prethermalized states are formed with distinct regions of impurity momenta determined by the mass ratio of impurity and BEC atoms. This can be employed to detect the mass renormalization of the impurity upon the formation of a polaron and paves the way to preparing nonequilibrium impurity-momentum distributions.
Dynamical Evolution of the Scalar Condensate in Heavy Ion Collisions
Csernai, Laszlo P.; Jeon, Sangyong; Kapusta, Joseph I.; Csernai, Laszlo P.; Ellis, Paul J.; Jeon, Sangyong; Kapusta, Joseph I.
2000-01-01
We derive the effective coarse-grained field equation for the scalar condensate of the linear sigma model in a simple and straightforward manner using linear response theory. In general, the necessary response functions cannot be obtained in perturbation theory but require a summation of ladder diagrams. We estimate these response functions using direct physical reasoning. The field equation is solved for hot matter undergoing either one or three dimensional expansion and cooling in the aftermath of a high energy nuclear collision. The results show that the time constant for returning the scalar condensate to thermal equilibrium is of order 2 fm/c.
Dynamical pions and kaons in the glueball condensate vacuum
Energy Technology Data Exchange (ETDEWEB)
Hansson, T.H.; Klabuar, D.; Zahed, I.
1987-07-01
The model for pions as collective modes in the glueball condensate vacuum is extended to incorporate time-independent fields and massive quarks. The quark mass dependence of
Energy Band and Josephson Dynamics of Spin-Orbit Coupled Bose-Einstein Condensates
Zhang, Xin; Yu, Zi-Fa; Xue, Ju-Kui
2015-10-01
We theoretically investigate the energy band structure and Josephson dynamics of a spin-orbit coupled Bose-Einstein condensate in a double-well potential. We study the energy band structure and the corresponding tunneling dynamics of the system by properly adjusting the SO coupling, Raman coupling, Zeeman field and atomic interactions. The coupled effects of SO coupling, Raman coupling, Zeeman field and atomic interactions lead to the appearance of complex energy band structure including the loop structure. Particularly, the emergence of the loop structure in energy band also depends on SO coupling, Raman coupling, Zeeman field and atomic interactions. Correspondingly, the Josephson dynamics of the system are strongly related to the energy band structure. Especially, the emergence of the loop structure results in complex tunneling dynamics, including suppression-revival transitions and self-trapping of atoms transfer between two spin states and two wells. This engineering provides a possible means for studying energy level and corresponding dynamics of two-species SO coupled BECs. Supported by the National Natural Science Foundation of China under Grant Nos. 11274255 and 11305132, by Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20136203110001, by the Natural Science Foundation of Gansu province under Grant No. 2011GS04358, and by Creation of Science and Technology of Northwest Normal University under Grant Nos. NWNU-KJCXGC-03-48, NWNU-LKQN-12-12
Spatial dynamics and spin squeezing in Bose-Einstein condensates
International Nuclear Information System (INIS)
Thanvanthri, Sulakshana; Dutton, Zachary
2007-01-01
We develop a cumulant based formalism to deterministically calculate the lowest order quantum fluctuations of a two-component Bose-Einstein condensate. We use this to study spin squeezing induced by the atom-atom interaction nonlinearity. Our formalism naturally accounts for the multimode spatial description of the condensate, extending previous spin squeezing work which assumed a single spatial mode. We study spin squeezing in both the miscible and immiscible (phase separating) regimes for the scattering lengths. In the miscible regime, we find the squeezing parameter deviates very little from the single spatial mode approach, while in the phase separating regime, we find the squeezing is slightly reduced, though significant squeezing still occurs
Thermodynamics and Dynamics of Bose condensation in a quasi-homogeneous gas
Navon, Nir; Schmidutz, Tobias; Gotlibovych, Igor; Gaunt, Alexander; Robert-de-Saint-Vincent, Martin; Smith, Robert; Hadzibabic, Zoran
2014-05-01
We present an experimental study of the thermodynamics and dynamics of Bose-Einstein condensation (BEC) in an optical-box trap. We first characterize the critical point for BEC, and observe saturation of the thermal component in a partially condensed cloud, in agreement with Einstein's textbook picture of a purely statistical phase transition. We also observed the quantum Joule-Thomson effect, namely isoenthalpic cooling of a non-interacting gas. We then investigate the dynamics of Bose condensation in the box potential following a rapid temperature quench through the phase transition, and focus on the time-evolution of the condensed fraction, the coherence length and the mean-field shift, that we probe via Bragg spectroscopy.
International Nuclear Information System (INIS)
Duan Ya-Fan; Xu Zhen; Qian Jun; Sun Jian-Fang; Jiang Bo-Nan; Hong Tao
2011-01-01
We numerically analyze the dynamic behavior of Bose—Einstein condensate (BEC) in a one-dimensional disordered potential before it completely loses spatial quantum coherence. We find that both the disorder statistics and the atom interactions produce remarkable effects on localization. We also find that the single phase of the initial condensate is broken into many small pieces while the system approaches localization, showing a counter-intuitive step-wise phase but not a thoroughly randomized phase. Although the condensates as a whole show less flow and expansion, the currents between adjacent phase steps retain strong time dependence. Thus we show explicitly that the localization of a finite size Bose—Einstein condensate is a dynamic equilibrium state. (general)
International Nuclear Information System (INIS)
Ruostekoski, J.; Dutton, Zachary
2007-01-01
We study dynamical and energetic instabilities in the transport properties of Bloch waves for atomic multicomponent Bose-Einstein condensates in optical lattices in the tight-binding limit. We obtain stability criteria analytically, as a function of superfluid velocities and interaction parameters, in several cases, for two-component and spinor condensates. In the two-species case we find that the presence of the other condensate component can stabilize the superfluid flow of an otherwise unstable condensate and that the free space dynamical miscibility condition of the two species can be reversed by tuning the superfluid flow velocities. In spin-1 condensates, we find the steady-state Bloch wave solutions and characterize their stability criteria. We find that generally more regions of dynamical instability arise for the polar than for the ferromagnetic solutions. In the presence of magnetic Zeeman shifts, we find a richer variety of condensate solutions and find that the linear Zeeman shift can stabilize the superfluid flow in several cases of interest
Spin tunnelling dynamics for spin-1 Bose-Einstein condensates in a swept magnetic field
International Nuclear Information System (INIS)
Wang Guanfang; Fu Libin; Liu Jie
2008-01-01
We investigate the spin tunnelling of spin-1 Bose-Einstein condensates in a linearly swept magnetic field with a mean-field treatment. We focus on the two typical alkali Bose atoms 87 Rb and 23 Na condensates and study their tunnelling dynamics according to the sweep rates of the external magnetic fields. In the adiabatic (i.e. slowly sweeping) and sudden (i.e. fast sweeping) limits, no tunnelling is observed. For the case of moderate sweep rates, the tunnelling dynamics is found to be very sensitive to the sweep rates, so the plots of tunnelling probability versus sweep rate only become resolvable at a resolution of 10 -4 G s -1 . Moreover, a conserved quantity standing for the magnetization in experiments is found to affect dramatically the dynamics of the spin tunnelling. Theoretically we have given a complete interpretation of the above findings, and our studies could stimulate the experimental study of spinor Bose-Einstein condensates
International Nuclear Information System (INIS)
1976-07-01
The ICECON computer code provides a method for conservatively calculating the long term back pressure transient in the containment resulting from a hypothetical Loss-of-Coolant Accident (LOCA) for PWR plants including ice condenser containment systems. The ICECON computer code was developed from the CONTEMPT/LT-022 code. A brief discussion of the salient features of a typical ice condenser containment is presented. Details of the ice condenser models are explained. The corrections and improvements made to CONTEMPT/LT-022 are included. The organization of the code, including the calculational procedure, is outlined. The user's manual, to be used in conjunction with the CONTEMPT/LT-022 user's manual, a sample problem, a time-step study (solution convergence) and a comparison of ICECON results with the results of the NSSS vendor are presented. In general, containment pressure calculated with the ICECON code agree with those calculated by the NSSS vendor using the same mass and energy release rates to the containment
A variational approach to Bogoliubov excitations and dynamics of dipolar Bose–Einstein condensates
International Nuclear Information System (INIS)
Kreibich, Manuel; Main, Jörg; Wunner, Günter
2013-01-01
We investigate the stability properties and the dynamics of Bose–Einstein condensates with axial symmetry, especially with dipolar long-range interaction, using both simulations on grids and variational calculations. We present an extended variational ansatz which is applicable for axial symmetry and show that this ansatz can reproduce the lowest eigenfrequencies of the Bogoliubov spectrum, and also the corresponding eigenfunctions. Our variational ansatz is capable of describing the roton instability of pancake-shaped dipolar condensates for arbitrary angular momenta. After investigating the linear regime we apply the ansatz to determine the dynamics and show how the angular collapse is correctly described within the variational framework. (paper)
Phase-space methods for the spin dynamics in condensed matter systems
Hurst, Jérôme; Hervieux, Paul-Antoine; Manfredi, Giovanni
2017-03-01
Using the phase-space formulation of quantum mechanics, we derive a four-component Wigner equation for a system composed of spin- fermions (typically, electrons) including the Zeeman effect and the spin-orbit coupling. This Wigner equation is coupled to the appropriate Maxwell equations to form a self-consistent mean-field model. A set of semiclassical Vlasov equations with spin effects is obtained by expanding the full quantum model to first order in the Planck constant. The corresponding hydrodynamic equations are derived by taking velocity moments of the phase-space distribution function. A simple closure relation is proposed to obtain a closed set of hydrodynamic equations. This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'.
Dynamics of Bose-Einstein condensates in novel optical potentials
Energy Technology Data Exchange (ETDEWEB)
Kueber, Johannes
2014-07-21
Matter wave interferometry offers a novel approach for high precision measurements, such as the determination of physical constants like the local gravity constant g or the fine-structure constant. Since its early demonstration, it has become an important tool in the fields of fundamental and applied physics. The present work covers the implementation of matter wave interferometers as well as the creation of novel guiding potentials for ultra-cold ensembles of atoms and Bose-Einstein condensates for this purpose. In addition, novel techniques for the manipulation of atoms with Bragg lattices are presented, serving as elements for interferometry. The measurements in this work are performed with a Bose-Einstein condensate of 25000 {sup 87}rubidium atoms created in a crossed optical dipole trap. The crossed optical dipole trap is loaded from a magneto-optical trap and allows a measurement every 25 s. This work introduces the novel technique of double Bragg diffraction as a tool for atom optics for the first time experimentally. The creation of beamsplitters and mirrors for advanced interferometric measurements is characterized. An in depth discussion on the momentum distribution of atomic clouds and its influence on double Bragg diffraction is given. Additionally experimental results for higher-order Bragg diffraction are explained and double Bragg diffraction is used to implement a full Ramsey-type interferometer. A second central result of this work is the implementation of novel guiding structures for ultra-cold atoms. These structures are created with conical refraction, an effect that occurs when light is guided along one of the optical axis of a bi-axial crystal. The conical refraction crystal used to operate the novel trapping geometries is a KGd(WO{sub 4}){sub 2} crystal that has been specifically cut orthogonal to one of the optical axis. Two regimes are discussed in detail: the creation of a toroidal matter wave guide and the implementation of a three
Vortex dynamics in coherently coupled Bose-Einstein condensates
Calderaro, Luca; Fetter, Alexander L.; Massignan, Pietro; Wittek, Peter
2017-02-01
In classical hydrodynamics with uniform density, vortices move with the local fluid velocity. This description is rewritten in terms of forces arising from the interaction with other vortices. Two such positive straight vortices experience a repulsive interaction and precess in a positive (anticlockwise) sense around their common centroid. A similar picture applies to vortices in a two-component, two-dimensional uniform Bose-Einstein condensate (BEC) coherently coupled through rf Rabi fields. Unlike the classical case, however, the rf Rabi coupling induces an attractive interaction and two such vortices with positive signs now rotate in the negative (clockwise) sense. Pairs of counter-rotating vortices are instead found to translate with uniform velocity perpendicular to the line joining their cores. This picture is extended to a single vortex in a two-component trapped BEC. Although two uniform vortex-free components experience familiar Rabi oscillations of particle-number difference, such behavior is absent for a vortex in one component because of the nonuniform vortex phase. Instead the coherent Rabi coupling induces a periodic vorticity transfer between the two components.
Dynamics of a trapped Bose-Einstein condensate in the presence of a one-dimensional optical lattice
Cataliotti, F S; Ferlaino, F; Fort, C; Maddaloni, P; Inguscio, M
2003-01-01
We explore the dynamics of a Bose-Einstein condensate created in the combined potential of a far-detuned laser standing wave superimposed to a 3D harmonic magnetic potential. We report the investigation of low-lying collective modes showing that the macroscopic dynamics along the optical lattice is strongly modified, resulting in a shift of the dipole and quadrupole mode frequencies depending on the height of the optical lattice, whereas the transverse breathing mode, occurring perpendicularly to the lattice axis, is not perturbed. The experimental findings are compared with the theoretical treatment that generalizes the hydrodynamic equation of superfluids for a weakly interacting Bose gas to include the effects of the periodic potential. We show that the array of condensates trapped in the optical wells and driven by the harmonic magnetic potential is equivalent to an array of Josephson junctions. In the regime of 'small' amplitude dipole oscillation the system performs a collective motion and we investigat...
Advances in chemical physics dynamical processes in condensed matter
Evans, Myron W
2009-01-01
Transport Properties and Soliton Models for Polyacetylene (M. Andretta, et al.). Development and Application of the Theory of Brownian Motion (W. Coffey). The Fading of Memory During the Regression of Structural Fluctuations (L. Dissado, et al.). Cooperative Molecular Behavior and Field Effects on Liquids: Experimental Considerations (G. Evans). A Review and Computer Simulation of the Molecular Dynamics of a Series of Specific Molecular Liquids (M. Evans and G. Evans). Recent Advances in Molecular-Dynamics Computer Simulation (D. Fincham and D. Heyes). Nonadiabatic Scattering Probl
Decoherence dynamics in interferometry with one-dimensional bose-einstein condensates
DEFF Research Database (Denmark)
Schumm, Thorsten; Hofferberth, Sebastian; Schmiedmayer, Jörg
2007-01-01
We perform interferometry with one-dimensional Bose-Einstein condensates in a double well potential. Using dressed adiabatic potentials on an atomchip, we dynamically split BECs, imposing a macroscopic coherence on the system. Fluctuations of the order parameter are revealed as local shifts in th...
Bright soliton dynamics in spin orbit-Rabi coupled Bose-Einstein condensates
Vinayagam, P. S.; Radha, R.; Bhuvaneswari, S.; Ravisankar, R.; Muruganandam, P.
2017-09-01
We investigate the dynamics of a spin-orbit (SO) coupled BECs in a time dependent harmonic trap and show the dynamical system to be completely integrable by constructing the Lax pair. We then employ gauge transformation approach to witness the rapid oscillations of the condensates for a relatively smaller value of SO coupling in a time independent harmonic trap compared to their counterparts in a transient trap. Keeping track of the evolution of the condensates in a transient trap during its transition from confining to expulsive trap, we notice that they collapse in the expulsive trap. We further show that one can manipulate the scattering length through Feshbach resonance to stretch the lifetime of the confining trap and revive the condensate. Considering a SO coupled state as the initial state, the numerical simulation indicates that the reinforcement of Rabi coupling on SO coupled BECs generates the striped phase of the bright solitons and does not impact the stability of the condensates despite destroying the integrability of the dynamical system.
Collapse Dynamics of an Attractive Box-Trapped Bose-Einstein Condensate
Eigen, Christoph; Gaunt, Alexander; Navon, Nir; Hadzibabic, Zoran; Smith, Robert
2016-05-01
We study the collapse dynamics of an attractive Bose-Einstein condensate confined in an optical box potential. After initiating the collapse (by suddenly changing the interaction to sufficiently negative) the wave-function shrinks in an accelerating manner. At some point (the collapse time), there is a sudden loss of atoms due to three-body recombination and an almost simultaneous emission of a shell of atoms with excess kinetic energy leaving the remnant condensate. We find that the collapse time, which we observe to vary over two orders of magnitude, can be expressed as a universal function of atom number, interaction strength and box size. Furthermore, we measure how the energy of the emitted shell and the remnant condensate atom number vary across this parameter space. In certain finely tuned conditions we observe a striking and unexplained bifurcation of possible outcomes.
Nagayama, Gyoko; Takematsu, Masaki; Mizuguchi, Hirotaka; Tsuruta, Takaharu
2015-07-07
The structure and thermodynamic properties of the liquid-vapor interface are of fundamental interest for numerous technological implications. For simple molecules, e.g., argon and water, the molecular condensation/evaporation behavior depends strongly on their translational motion and the system temperature. Existing molecular dynamics (MD) results are consistent with the theoretical predictions based on the assumption that the liquid and vapor states in the vicinity of the liquid-vapor interface are isotropic. Additionally, similar molecular condensation/evaporation characteristics have been found for long-chain molecules, e.g., dodecane. It is unclear, however, whether the isotropic assumption is valid and whether the molecular orientation or the chain length of the molecules affects the condensation/evaporation behavior at the liquid-vapor interface. In this study, MD simulations were performed to study the molecular condensation/evaporation behavior of the straight-chain alkanes, i.e., butane, octane, and dodecane, at the liquid-vapor interface, and the effects of the molecular orientation and chain length were investigated in equilibrium systems. The results showed that the condensation/evaporation behavior of chain molecules primarily depends on the molecular translational energy and the surface temperature and is independent of the molecular chain length. Furthermore, the orientation at the liquid-vapor interface was disordered when the surface temperature was sufficiently higher than the triple point and had no significant effect on the molecular condensation/evaporation behavior. The validity of the isotropic assumption was confirmed, and we conclude that the condensation/evaporation coefficients can be predicted by the liquid-to-vapor translational length ratio, even for chain molecules.
Dynamics of dark-bright solitons in cigar-shaped Bose-Einstein condensates
Energy Technology Data Exchange (ETDEWEB)
Middelkamp, S. [Zentrum fuer Optische Quantentechnologien, Universitaet Hamburg, 22761 Hamburg (Germany); Chang, J.J.; Hamner, C. [Washington State University, Department of Physics and Astronomy, Pullman, WA 99164 (United States); Carretero-Gonzalez, R. [Nonlinear Physics Group, Escuela Tecnica Superior de Ingenieria Informatica, Departamento de Fisica Aplicada I, Universidad de Sevilla, Avda. Reina Mercedes s/n, 41012 Sevilla (Spain); Kevrekidis, P.G., E-mail: kevrekid@gmail.co [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-4515 (United States); Achilleos, V.; Frantzeskakis, D.J. [Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 157 84 (Greece); Schmelcher, P. [Zentrum fuer Optische Quantentechnologien, Universitaet Hamburg, 22761 Hamburg (Germany); Engels, P. [Washington State University, Department of Physics and Astronomy, Pullman, WA 99164 (United States)
2011-01-17
We explore the stability and dynamics of dark-bright (DB) solitons in two-component elongated Bose-Einstein condensates by developing effective one-dimensional vector equations and solving the three-dimensional Gross-Pitaevskii equations. A strong dependence of the oscillation frequency and of the stability of the DB soliton on the atom number of its components is found; importantly, the wave may become dynamically unstable even in the 1D regime. As the atom number in the dark-soliton-supporting component is further increased, spontaneous symmetry breaking leads to oscillatory dynamics in the transverse degrees of freedom. Moreover, the interactions of two DB solitons are investigated with an emphasis on the importance of their relative phases. Experimental results showcasing multiple DB soliton oscillations and a DB-DB collision in a Bose-Einstein condensate consisting of two hyperfine states of {sup 87}Rb confined in an elongated optical dipole trap are presented.
MOLOCH computer code for molecular-dynamics simulation of processes in condensed matter
Directory of Open Access Journals (Sweden)
Derbenev I.V.
2011-01-01
Full Text Available Theoretical and experimental investigation into properties of condensed matter is one of the mainstreams in RFNC-VNIITF scientific activity. The method of molecular dynamics (MD is an innovative method of theoretical materials science. Modern supercomputers allow the direct simulation of collective effects in multibillion atom sample, making it possible to model physical processes on the atomistic level, including material response to dynamic load, radiation damage, influence of defects and alloying additions upon material mechanical properties, or aging of actinides. During past ten years, the computer code MOLOCH has been developed at RFNC-VNIITF. It is a parallel code suitable for massive parallel computing. Modern programming techniques were used to make the code almost 100% efficient. Practically all instruments required for modelling were implemented in the code: a potential builder for different materials, simulation of physical processes in arbitrary 3D geometry, and calculated data processing. A set of tests was developed to analyse algorithms efficiency. It can be used to compare codes with different MD implementation between each other.
Mordik, S N
2002-01-01
The third-order transfer matrices are calculated for an electrostatic toroidal sector condenser using a rigorously conserved matrix method that implies the conservation of the beam phase volume at each step in the calculations. The transfer matrices (matrizants) obtained, include the fringing-field effect due to the stray fields. In the case of a rectangular distribution of the field components along the optical axis, the analytical expressions for all aberration coefficients, including the dispersion ones, are derived accurate to the third-order terms. In simulations of real fields with the stray field width other than zero, a smooth distribution of the field components is used for which similar aberration coefficients were calculated by means of the conserved numerical method . It has been found that for a smooth model, as the stray field width tends to zero, the aberration coefficients approach the corresponding aberration values in the rectangular model.
Chen, Sow-Hsin; Baglioni, Piero
2006-09-01
This special issue of Journal of Physics: Condensed Matter gathers together a series of contributions presented at the workshop entitled `Topics in the Application of Scattering Methods to Investigate the Structure and Dynamics of Soft Condensed Matter' held at Pensione Bencista, Fiesole, Italy, a wonderful Italian jewel tucked high in the hills above Florence. This immaculate 14th century villa is a feast for the eyes with antiques and original artwork everywhere you turn, and a stunning view of Florence, overlooking numerous villas and groves of olive trees. The meeting consisted of about 40 invited talks delivered by a selected group of prominent physicists and chemists from the USA, Mexico, Europe and Asia working in the fields of complex and glassy liquids. The topics covered by the talks included: simulations on the liquid-liquid transition phenomenon dynamic crossover in deeply supercooled confined water thermodynamics and dynamics of complex fluids dynamics of interfacial water structural arrest transitions in colloidal systems structure and dynamics in complex systems structure of supramolecular assemblies The choice of topics is obviously heavily biased toward the current interests of the two organizers of the workshop, in view of the fact that one of the incentives for organizing the meeting was to celebrate Sow-Hsin Chen’s life-long scientific activities on the occasion of his 70th birthday. The 21 articles presented in this issue are a state-of-the-art description of the different aspects reported at the workshop from all points of view---experimental, theoretical and numerical. The interdisciplinary nature of the talks should make this special issue of interest to a broad community of scientists involved in the study of the properties of complex fluids, soft condensed matter and disordered glassy systems. We are grateful to the Consorzio per lo Sviluppo dei Sistemi a Grande Interfase (CSGI), Florence, Italy and to the Materials Science Program of
Ernst, Timothy C.; Zigan, James A.
2017-06-20
The disclosure describes a non-condensable gas collection, detection, and removal system for a WHR system that helps to maintain cycle efficiency of the WHR system across the life of an engine system associated with the WHR system. A storage volume is configured to collect non-condensable gas received from the working fluid circuit, and a release valve is configured to selectively release non-condensable gas contained within the storage volume.
Gas dynamics, optics and chemistry of an aircraft condensable wake
Energy Technology Data Exchange (ETDEWEB)
Grinats, E.S.; Kashevarov, A.V.; Stasenko, A.L. [Central Aerohydrodynamic Inst., Zhukovsky (Russian Federation)
1997-12-31
Prediction of the properties of a jet-and-vortex wake from an individual airplane is of great interest as the first step to assessment of the possible global changes in the atmosphere due to the world civil aviation. Several mathematical models of the different regions of an aircraft wake and corresponding numerical results are presented. The axisymmetric exhaust jet was simulated on the base of the well-known k-{epsilon} model of turbulence. Jet chemistry was investigated on the base of kinetic scheme of the gas phase reactions of enriched by including chemisorption by water droplets of several species and by taking into account of the photochemical processes. In the 3D far wake model, the numerical results for distribution of species exhausted by the engines and entrapped by the velocity field of two parallel vortices are shown. (R.P.) 7 refs.
Dynamical creation of complex vector solitons in spinor Bose-Einstein condensates
International Nuclear Information System (INIS)
Xiong Bo; Gong Jiangbin
2010-01-01
By numerical simulations of the Gross-Pitaevskii mean-field equations, we show that the dynamical creation of stable complex vector solitons in a homogeneous spin-1 Bose-Einstein condensate can be achieved by applying a localized magnetic field for a certain duration, with the initial uniform density prepared differently for the formation of different vector solitons. In particular, it is shown that stable dark-bright-dark vector solitons, dark-bright-bright vector solitons, and other analogous solutions can be dynamically created. It is also found that the peak intensity and the group velocity of the vector solitons thus generated can be tuned by adjusting the applied magnetic field. Extensions of our approach also allow for the creation of vector-soliton chains or the pumping of many vector solitons. The results can be useful for possible vector-soliton-based applications of dilute Bose-Einstein condensates.
Effective one-component description of two-component Bose-Einstein condensate dynamics
International Nuclear Information System (INIS)
Dutton, Zachary; Clark, Charles W.
2005-01-01
We investigate dynamics in two-component Bose-Einstein condensates in the context of coupled Gross-Pitaevskii equations and derive results for the evolution of the total density fluctuations. Using these results, we show how, in many cases of interest, the dynamics can be accurately described with an effective one-component Gross-Pitaevskii equation for one of the components, with the trap and interaction coefficients determined by the relative differences in the scattering lengths. We discuss the model in various regimes, where it predicts breathing excitations, and the formation of vector solitons. An effective nonlinear evolution is predicted for some cases of current experimental interest. We then apply the model to construct quasistationary states of two-component condensates
Dynamics of vortex assisted metal condensation in superfluid helium.
Popov, Evgeny; Mammetkuliyev, Muhammet; Eloranta, Jussi
2013-05-28
Laser ablation of copper and silver targets immersed in bulk normal and superfluid (4)He was studied through time-resolved shadowgraph photography. In normal fluid, only a sub-millimeter cavitation bubble is created and immediate formation of metal clusters is observed within a few hundred microseconds. The metal clusters remain spatially tightly focused up to 15 ms, and it is proposed that this observation may find applications in particle image velocimetry. In superfluid helium, the cavitation bubble formation process is distinctly different from the normal fluid. Due to the high thermal conductivity and an apparent lag in the breakdown of superfluidity, about 20% of the laser pulse energy was transferred directly into the liquid and a large gas bubble, up to several millimeters depending on laser pulse energy, is created. The internal temperature of the gas bubble is estimated to exceed 9 K and the following bubble cool down period therefore includes two separate phase transitions: gas-normal liquid and normal liquid-superfluid. The last stage of the cool down process was assigned to the superfluid lambda transition where a sudden formation of large metal clusters is observed. This is attributed to high vorticity created in the volume where the gas bubble previously resided. As shown by theoretical bosonic density functional theory calculations, quantized vortices can trap atoms and dimers efficiently, exhibiting static binding energies up to 22 K. This, combined with hydrodynamic Bernoulli attraction, yields total binding energies as high as 35 K. For larger clusters, the static binding energy increases as a function of the volume occupied in the liquid to minimize the surface tension energy. For heliophobic species an energy barrier develops as a function of the cluster size, whereas heliophilics show barrierless entry into vortices. The present theoretical and experimental observations are used to rationalize the previously reported metal nanowire assembly in
International Nuclear Information System (INIS)
Ibrahim, Oussama; Fardoun, Farouk; Younes, Rafic; Louahlia-Gualous, Hasna
2014-01-01
This paper presents a dynamic simulation model to predict the performance of an ASHPWH (air source heat pump water heater). The developed model is used to assess its performance in the Lebanese context. It is shown that for the four Lebanese climatic zones, the expected monthly values of the average COP (coefficient of performance) varies from 2.9 to 5, leading to high efficiencies compared with conventional electric water heaters. The energy savings and GHG (greenhouse gas) emissions reduction are investigated for each zone. Furthermore, it is recommended to use the ASHPWH during the period of highest daily ambient temperatures (noon or afternoon), assuming that the electricity tariff and hot water loads are constant. In addition, an optimal management model for the ASHPWH is developed and applied for a typical winter day of Beirut. Moreover, the developed dynamic model of ASHPWH is used to compare the performance of three similar systems that differ only with the condenser geometry, where results show that using mini-condenser geometries increase the COP (coefficient of performance) and consequently, more energy is saved as well as more GHG emissions are reduced. In addition, the condenser “surface compactness” is increased giving rise to an efficient compact heat exchanger. - Highlights: • Numerical modeling and experimental validation for ASHPWH (air source heat pump water heater). • Optimization of the ASHPWH-condenser length. • Comparison of the ASHPWH with conventional electric water heater according to energy efficiency and green gas house emissions. • Development of an energetic-economic optimal management model for ASHPWH. • Energetic and environmental assessment of ASHPWH with mini-tubes condensers
Dynamics of double-well Bose–Einstein condensates subject to external Gaussian white noise
International Nuclear Information System (INIS)
Zheng Hanlei; Hao Yajiang; Gu Qiang
2013-01-01
Dynamical properties of the Bose–Einstein condensate in a double-well potential subject to Gaussian white noise are investigated by numerically solving the time-dependent Gross–Pitaevskii equation. The Gaussian white noise is used to describe influence of the random environmental disturbance on the double-well condensate. Dynamical evolutions from three different initial states, the Josephson oscillation state, the running phase and π-mode macroscopic quantum self-trapping states, are considered. It is shown that the system is rather robust with respect to the weak noise whose strength is small and change rate is high. If the evolution time is sufficiently long, the weak noise will finally drive the system to evolve from high-energy states to low-energy states, but in a manner rather different from the energy-dissipation effect. In the presence of strong noise with either large strength or slow change rate, the double-well condensate may exhibit very irregular dynamical behaviours. (paper)
Effects of non-condensable gas on the dynamic oscillations of cavitation bubbles
Zhang, Yuning
2016-11-01
Cavitation is an essential topic of multiphase flow with a broad range of applications. Generally, there exists non-condensable gas in the liquid and a complex vapor/gas mixture bubble will be formed. A rigorous prediction of the dynamic behavior of the aforementioned mixture bubble is essential for the development of a complete cavitation model. In the present paper, effects of non-condensable gas on the dynamic oscillations of the vapor/gas mixture bubble are numerically investigated in great detail. For the completeness, a large parameter zone (e.g. bubble radius, frequency and ratio between gas and vapor) is investigated with many demonstrating examples. The mechanisms of mass diffusion are categorized into different groups with their characteristics and dominated regions given. Influences of non-condensable gas on the wave propagation (e.g. wave speed and attenuation) in the bubbly liquids are also briefly discussed. Specifically, the minimum wave speed is quantitatively predicted in order to close the pressure-density coupling relationship usually employed for the cavitation modelling. Finally, the application of the present finding on the development of cavitation model is demonstrated with a brief discussion of its influence on the cavitation dynamics. This work was financially supported by the National Natural Science Foundation of China (Project No.: 51506051).
The Dynamics of Partial Cavities and Effect of Non-Condensable Gas
Makiharju, Simo A.; Ganesh, Harish; Ceccio, Steven L.
2015-11-01
Partial cavitation is encountered in a variety of common applications, from fuel injectors to lifting surfaces, and in general it has detrimental effects on the system wear and performance. Partial cavities undergoing auto-oscillation can cause large pressure oscillations, unsteady hydrodynamic loading, and significant noise. In the present study, experiments were conducted focusing on the dynamics of shedding cavities forming in a canonical geometry (downstream of a wedge apex). The inlet cavitation number was fixed at 2.0 and the Reynolds number based on the hydraulic diameter was 6x105. The effects of dissolved gas content and of non-condensable gas injection into the cavity were carefully studied utilizing dynamic pressure transducers and x-ray densitometry. Gas was injected either immediately downstream of the wedge's apex or further downstream into mid-cavity. The gas injected near the wedge apex was found to end up in the separated shear layer, and relatively miniscule amounts of gas were enough to significantly reduce the vapor production rate and dampen the cavity's auto-oscillations. In addition, the results suggest that non-condensable gas injection can cause the shedding mechanism to switch from one dominated by condensation shock to one dominated by re-entrant liquid jet. Work supported by the Office of Naval Research Grant N00014-14-1-0292, program manager Dr. Ki-Han Kim.
Thermalization of the quark-gluon plasma and dynamical formation of Bose-Einstein Condensate
International Nuclear Information System (INIS)
Liao, Jinfeng
2013-01-01
We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the pre-equilibrium gluonic matter ( g lasma ) is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an emergent property of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop the kinetic approach for describing this highly overpopulated system and find approximate scaling solutions as well as numerically study the onset of condensation. Finally we also discuss possible phenomenological implications.
Kibble-Zurek dynamics in an array of coupled binary Bose condensates
Xu, Jun; Wu, Shuyuan; Qin, Xizhou; Huang, Jiahao; Ke, Yongguan; Zhong, Honghua; Lee, Chaohong
2016-03-01
Universal dynamics of spontaneous symmetry breaking is central to understanding the universal behavior of spontaneous defect formation in various systems from the early universe, condensed-matter systems to ultracold atomic systems. We explore the universal real-time dynamics in an array of coupled binary atomic Bose-Einstein condensates in optical lattices, which undergo a spontaneous symmetry breaking from the symmetric Rabi oscillation to the broken-symmetry self-trapping. In addition to Goldstone modes, there exist gapped Higgs modes whose excitation gap vanishes at the critical point. In the slow passage through the critical point, we analytically find that the symmetry-breaking dynamics obeys the Kibble-Zurek mechanism. From the scalings of bifurcation delay and domain formation, we numerically extract two Kibble-Zurek exponents, b1=ν/(1+ν z) and b2=1/(1+ν z) , which give the static correlation-length critical exponent ν and the dynamic critical exponent z. Our approach provides an efficient way for the simultaneous determination of the critical exponents ν and z for a continuous phase transition.
Rossi, Mariana; Liu, Hanchao; Paesani, Francesco; Bowman, Joel; Ceriotti, Michele
2014-11-14
Including quantum mechanical effects on the dynamics of nuclei in the condensed phase is challenging, because the complexity of exact methods grows exponentially with the number of quantum degrees of freedom. Efforts to circumvent these limitations can be traced down to two approaches: methods that treat a small subset of the degrees of freedom with rigorous quantum mechanics, considering the rest of the system as a static or classical environment, and methods that treat the whole system quantum mechanically, but using approximate dynamics. Here, we perform a systematic comparison between these two philosophies for the description of quantum effects in vibrational spectroscopy, taking the Embedded Local Monomer model and a mixed quantum-classical model as representatives of the first family of methods, and centroid molecular dynamics and thermostatted ring polymer molecular dynamics as examples of the latter. We use as benchmarks D2O doped with HOD and pure H2O at three distinct thermodynamic state points (ice Ih at 150 K, and the liquid at 300 K and 600 K), modeled with the simple q-TIP4P/F potential energy and dipole moment surfaces. With few exceptions the different techniques yield IR absorption frequencies that are consistent with one another within a few tens of cm(-1). Comparison with classical molecular dynamics demonstrates the importance of nuclear quantum effects up to the highest temperature, and a detailed discussion of the discrepancies between the various methods let us draw some (circumstantial) conclusions about the impact of the very different approximations that underlie them. Such cross validation between radically different approaches could indicate a way forward to further improve the state of the art in simulations of condensed-phase quantum dynamics.
Directory of Open Access Journals (Sweden)
M. D. Petters
2008-10-01
Full Text Available The ability of a particle to serve as a cloud condensation nucleus in the atmosphere is determined by its size, hygroscopicity and its solubility in water. Usually size and hygroscopicity alone are sufficient to predict CCN activity. Single parameter representations for hygroscopicity have been shown to successfully model complex, multicomponent particles types. Under the assumption of either complete solubility, or complete insolubility of a component, it is not necessary to explicitly include that component's solubility into the single parameter framework. This is not the case if sparingly soluble materials are present. In this work we explicitly account for solubility by modifying the single parameter equations. We demonstrate that sensitivity to the actual value of solubility emerges only in the regime of 2×10^{−1}–5×10^{−4}, where the solubility values are expressed as volume of solute per unit volume of water present in a saturated solution. Compounds that do not fall inside this sparingly soluble envelope can be adequately modeled assuming they are either infinitely soluble in water or completely insoluble.
Pierre, Sadrach; Duke, Jessica R.; Hele, Timothy J. H.; Ananth, Nandini
2017-12-01
We investigate the mechanisms of condensed phase proton-coupled electron transfer (PCET) using Mapping-Variable Ring Polymer Molecular Dynamics (MV-RPMD), a recently developed method that employs an ensemble of classical trajectories to simulate nonadiabatic excited state dynamics. Here, we construct a series of system-bath model Hamiltonians for the PCET, where four localized electron-proton states are coupled to a thermal bath via a single solvent mode, and we employ MV-RPMD to simulate state population dynamics. Specifically, for each model, we identify the dominant PCET mechanism, and by comparing against rate theory calculations, we verify that our simulations correctly distinguish between concerted PCET, where the electron and proton transfer together, and sequential PCET, where either the electron or the proton transfers first. This work represents a first application of MV-RPMD to multi-level condensed phase systems; we introduce a modified MV-RPMD expression that is derived using a symmetric rather than asymmetric Trotter discretization scheme and an initialization protocol that uses a recently derived population estimator to constrain trajectories to a dividing surface. We also demonstrate that, as expected, the PCET mechanisms predicted by our simulations are robust to an arbitrary choice of the initial dividing surface.
A Time-Splitting and Sine Spectral Method for Dynamics of Dipolar Bose-Einstein Condensate
Directory of Open Access Journals (Sweden)
Si-Qi Li
2013-01-01
Full Text Available A two-component Bose-Einstein condensate (BEC described by two coupled a three-dimension Gross-Pitaevskii (GP equations is considered, where one equation has dipole-dipole interaction while the other one has only the usual s-wave contact interaction, in a cigar trap. The time-splitting and sine spectral method in space is proposed to discretize the time-dependent equations for computing the dynamics of dipolar BEC. The singularity in the dipole-dipole interaction brings significant difficulties both in mathematical analysis and in numerical simulations. Numerical results are given to show the efficiency of this method.
A study of helicopter stability and control including blade dynamics
Zhao, Xin; Curtiss, H. C., Jr.
1988-01-01
A linearized model of rotorcraft dynamics has been developed through the use of symbolic automatic equation generating techniques. The dynamic model has been formulated in a unique way such that it can be used to analyze a variety of rotor/body coupling problems including a rotor mounted on a flexible shaft with a number of modes as well as free-flight stability and control characteristics. Direct comparison of the time response to longitudinal, lateral and directional control inputs at various trim conditions shows that the linear model yields good to very good correlation with flight test. In particular it is shown that a dynamic inflow model is essential to obtain good time response correlation, especially for the hover trim condition. It also is shown that the main rotor wake interaction with the tail rotor and fixed tail surfaces is a significant contributor to the response at translational flight trim conditions. A relatively simple model for the downwash and sidewash at the tail surfaces based on flat vortex wake theory is shown to produce good agreement. Then, the influence of rotor flap and lag dynamics on automatic control systems feedback gain limitations is investigated with the model. It is shown that the blade dynamics, especially lagging dynamics, can severly limit the useable values of the feedback gain for simple feedback control and that multivariable optimal control theory is a powerful tool to design high gain augmentation control system. The frequency-shaped optimal control design can offer much better flight dynamic characteristics and a stable margin for the feedback system without need to model the lagging dynamics.
DEFF Research Database (Denmark)
Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund
2014-01-01
The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...
DEFF Research Database (Denmark)
Nielsen, Toke Rammer; Rose, Jørgen; Kragh, Jesper
2009-01-01
must be calculated under conditions with condensation and freezing. This article presents a dynamic model of a counter flow air to air heat exchanger taking into account condensation and freezing and melting of ice. The model is implemented in Simulink and results are compared to measurements......In cold climates heat recovery in the ventilation system is essential to reduce heating energy demand. Condensation and freezing occur often in efficient heat exchangers used in cold climates. To develop efficient heat exchangers and defrosting strategies for cold climates, heat and mass transfer...... on a prototype heat exchanger for cold climates....
Dynamics and Interaction of Quantized Vortex Lines in Trapped Bose-Einstein Condensates
Dalfovo, Franco; Serafini, Simone; Iseni, Elena; Bienaimé, Tom; Bisset, Russell N.; Lamporesi, Giacomo; Ferrari, Gabriele; Galantucci, Luca; Barenghi, Carlo F.
2017-04-01
We report experimental and numerical observations of the dynamics and the interaction of 3D quantum vortex filaments in a cigar-shaped atomic Bose-Einstein condensate. Vortices are spontaneously created by the Kibble-Zurek mechanism by quenching the system across the BEC transition. We then use an innovative imaging technique which exploits self-interference effects of out-coupled atoms in order to extract both the position and orientation of vortex lines from a temporal sequence of absorption images. We combine experiments and numerical Gross-Pitaevskii simulations to study the interaction between two vortices approaching at various relative speeds and angles. We show that the interaction between vortex lines in a finite system is rather different from the one in infinite uniform superfluids. In particular, the presence of boundaries induce new effects, such as rebounds, double reconnections, and ejections. These processes may play an important role in the dynamics of trapped condensates in multi-vortex and turbulent-like configurations, and, on a wider perspective, they can represent novel keys for better understanding the behavior of superfluids near boundaries.
Population and phase dynamics of F=1 spinor condensates in an external magnetic field
International Nuclear Information System (INIS)
Romano, D.R.; Passos, E.J.V. de
2004-01-01
We show that the classical dynamics underlying the mean-field description of homogeneous mixtures of spinor F=1 Bose-Einstein condensates in an external magnetic field is integrable as a consequence of number conservation and axial symmetry in spin space. The population dynamics depends only on the quadratic term of the Zeeman energy and on the strength of the spin-dependent term of the atom-atom interaction. We determine the equilibrium populations as function of the ratio of these two quantities and the miscibility of the hyperfine components in the ground state spinors are thoroughly discussed. Outside the equilibrium, the populations are always a periodic function of time where the periodic motion can be a libration or a rotation. Our studies also indicate the absence of metastability
Quantum mechanical simulations of condensed-phase decomposition dynamics in molten RDX
Schweigert, Igor
2013-06-01
A reaction model for condensed-phase decomposition of RDX under pressures up to several GPa is needed to support mesoscale simulations of the energetic material's sensitivity to thermal and shock loading. A prerequisite to developing such a model is the identification of the chemical pathways that control the rate of the initial dissociation and the subsequent decomposition of molecular fragments. We use quantum mechanics based molecular dynamics simulations to follow the decomposition dynamics under high-pressure conditions and to identify the reaction mechanisms. This presentation will describe current applications to the liquid-phase decomposition of molten RDX. This work was supported by the Naval Research Laboratory, by the Office of Naval Research, and by the DOD High Performance Computing Modernization Program Software Application Institute for Multiscale Reactive Modeling of Insensitive Munitions.
Many-body quantum dynamics in the decay of bent dark solitons of Bose-Einstein condensates
Katsimiga, G. C.; Mistakidis, S. I.; Koutentakis, G. M.; Kevrekidis, P. G.; Schmelcher, P.
2017-12-01
The beyond mean-field (MF) dynamics of a bent dark soliton (BDS) embedded in a two-dimensional repulsively interacting Bose-Einstein condensate is explored. We examine the case of a single BDS comparing the MF dynamics to a correlated approach, the multi-configuration time-dependent Hartree method for bosons. Dynamical snaking of this bent structure is observed, signaling the onset of fragmentation which becomes significant during the vortex nucleation. In contrast to the MF approximation ‘filling’ of the vortex core is observed, leading in turn to the formation of filled-core vortices, instead of the MF vortex-antivortex pairs. The resulting smearing effect in the density is a rather generic feature, occurring when solitonic structures are exposed to quantum fluctuations. Here, we show that this filling owes its existence to the dynamical building of an antidark structure developed in the next-to-leading order orbital. We further demonstrate that the aforementioned beyond MF dynamics can be experimentally detected using the variance of single shot measurements. Additionally, a variety of excitations including vortices, oblique dark solitons, and open ring dark soliton-like structures building upon higher-lying orbitals is observed. We demonstrate that signatures of the higher-lying orbital excitations emerge in the total density, and can be clearly captured by inspecting the one-body coherence. In the latter context, the localization of one-body correlations exposes the existence of the multi-orbital vortex-antidark structure.
Miljkovic, Nenad; Enright, Ryan; Wang, Evelyn N
2012-02-28
Condensation on superhydrophobic nanostructured surfaces offers new opportunities for enhanced energy conversion, efficient water harvesting, and high performance thermal management. These surfaces are designed to be Cassie stable and favor the formation of suspended droplets on top of the nanostructures as compared to partially wetting droplets which locally wet the base of the nanostructures. These suspended droplets promise minimal contact line pinning and promote passive droplet shedding at sizes smaller than the characteristic capillary length. However, the gas films underneath such droplets may significantly hinder the overall heat and mass transfer performance. We investigated droplet growth dynamics on superhydrophobic nanostructured surfaces to elucidate the importance of droplet morphology on heat and mass transfer. By taking advantage of well-controlled functionalized silicon nanopillars, we observed the growth and shedding behavior of suspended and partially wetting droplets on the same surface during condensation. Environmental scanning electron microscopy was used to demonstrate that initial droplet growth rates of partially wetting droplets were 6× larger than that of suspended droplets. We subsequently developed a droplet growth model to explain the experimental results and showed that partially wetting droplets had 4-6× higher heat transfer rates than that of suspended droplets. On the basis of these findings, the overall performance enhancement created by surface nanostructuring was examined in comparison to a flat hydrophobic surface. We showed these nanostructured surfaces had 56% heat flux enhancement for partially wetting droplet morphologies and 71% heat flux degradation for suspended morphologies in comparison to flat hydrophobic surfaces. This study provides insights into the previously unidentified role of droplet wetting morphology on growth rate, as well as the need to design Cassie stable nanostructured surfaces with tailored droplet
Kim, Jae In; Na, Sungsoo; Eom, Kilho
2011-01-15
Normal mode analysis (NMA) with coarse-grained model, such as elastic network model (ENM), has allowed the quantitative understanding of protein dynamics. As the protein size is increased, there emerges the expensive computational process to find the dynamically important low-frequency normal modes due to diagonalization of massive Hessian matrix. In this study, we have provided the domain decomposition-based structural condensation method that enables the efficient computations on low-frequency motions. Specifically, our coarse-graining method is established by coupling between model condensation (MC; Eom et al., J Comput Chem 2007, 28, 1400) and component mode synthesis (Kim et al., J Chem Theor Comput 2009, 5, 1931). A protein structure is first decomposed into substructural units, and then each substructural unit is coarse-grained by MC. Once the NMA is implemented to coarse-grained substructural units, normal modes and natural frequencies for each coarse-grained substructural unit are assembled by using geometric constraints to provide the normal modes and natural frequencies for whole protein structure. It is shown that our coarse-graining method enhances the computational efficiency for analysis of large protein complexes. It is clearly suggested that our coarse-graining method provides the B-factors of 100 large proteins, quantitatively comparable with those obtained from original NMA, with computational efficiency. Moreover, the collective behaviors and/or the correlated motions for model proteins are well delineated by our suggested coarse-grained models, quantitatively comparable with those computed from original NMA. It is implied that our coarse-grained method enables the computationally efficient studies on conformational dynamics of large protein complex.
Dynamical criteria for a unified gauge theory (including gravity)
International Nuclear Information System (INIS)
1979-01-01
It is shown that local gauge invariance together with dynamical (and possibly Higgs) symmetry breaking can be taken as a basis for a unified gauge theory including gravity. The criterion for the breakdown of the linear gauge symmetry of the space-time sector turns out to be the absence of a prior geometry. The usual postulates of general relativity, such as general coordinate invariance, etc., follow from the above two criteria. Gravity actions that are natural from the point of view are discussed. The extension to superspace relevant to gauge supergroups is also given, including a large number of linear and quadratic superspace invariants
International Nuclear Information System (INIS)
Damski, Bogdan; Zurek, Wojciech H
2008-01-01
We discuss the dynamics of a quantum phase transition in a spin-1 Bose-Einstein condensate when it is driven from the magnetized broken-symmetry phase to the unmagnetized 'symmetric' polar phase. We determine where the condensate goes out of equilibrium as it approaches the critical point, and compute the condensate magnetization at the critical point. This is done within a quantum Kibble-Zurek scheme traditionally employed in the context of symmetry-breaking quantum phase transitions. Then we study the influence of the non-equilibrium dynamics near a critical point on the condensate magnetization. In particular, when the quench stops at the critical point, nonlinear oscillations of magnetization occur. They are characterized by a period and an amplitude that are inversely proportional. If we keep driving the condensate far away from the critical point through the unmagnetized 'symmetric' polar phase, the amplitude of magnetization oscillations slowly decreases reaching a nonzero asymptotic value. That process is described by an equation that can be mapped onto the classical mechanical problem of a particle moving under the influence of harmonic and 'anti-friction' forces whose interplay leads to surprisingly simple fixed-amplitude oscillations. We obtain several scaling results relating the condensate magnetization to the quench rate, and verify numerically all analytical predictions
Dynamics of a period-3 pattern-loaded Bose-Einstein condensate in an optical lattice
International Nuclear Information System (INIS)
Rey, A.-M.; Blakie, P.B.; Clark, Charles W.
2003-01-01
We discuss the dynamics of a Bose-Einstein condensate initially loaded into every third site of an optical lattice using a description based upon the discrete nonlinear Schroedinger equation. An analytic solution is developed for the case of a periodic initial condition and is compared with numerical simulations for more general initial configurations. We show that mean field effects in this system can cause macroscopic quantum self-trapping, a phenomenon already predicted for double-well systems. In the presence of a uniform external potential, the atoms exhibit generalized Bloch oscillations which can be interpreted in terms of the interference of three different Bloch states. We also discuss how the momentum distribution of the system can be used as an experimental signature of the macroscopic self-trapping effect
Generation of dark solitons and their instability dynamics in two-dimensional condensates
Verma, Gunjan; Rapol, Umakant D.; Nath, Rejish
2017-04-01
We analyze numerically the formation and the subsequent dynamics of two-dimensional matter wave dark solitons in a Thomas-Fermi rubidium condensate using various techniques. An initially imprinted sharp phase gradient leads to the dynamical formation of a stationary soliton as well as very shallow gray solitons, whereas a smooth gradient only creates gray solitons. The depth and hence, the velocity of the soliton is provided by the spatial width of the phase gradient, and it also strongly influences the snake-instability dynamics of the two-dimensional solitons. The vortex dipoles stemming from the unstable soliton exhibit rich dynamics. Notably, the annihilation of a vortex dipole via a transient dark lump or a vortexonium state, the exchange of vortices between either a pair of vortex dipoles or a vortex dipole and a single vortex, and so on. For sufficiently large width of the initial phase gradient, the solitons may decay directly into vortexoniums instead of vortex pairs, and also the decay rate is augmented. Later, we discuss alternative techniques to generate dark solitons, which involve a Gaussian potential barrier and time-dependent interactions, both linear and periodic. The properties of the solitons can be controlled by tuning the amplitude or the width of the potential barrier. In the linear case, the number of solitons and their depths are determined by the quench time of the interactions. For the periodic modulation, a transient soliton lattice emerges with its periodicity depending on the modulation frequency, through a wave number selection governed by the local Bogoliubov spectrum. Interestingly, for sufficiently low barrier potential, both Faraday pattern and soliton lattice coexist. The snake instability dynamics of the soliton lattice is characteristically modified if the Faraday pattern is present.
Rykaczewski, Konrad; Chinn, Jeff; Walker, Marlon L; Scott, John Henry J; Chinn, Amy; Jones, Wanda
2011-12-27
Nanoparticles adsorbed onto the surface of a drop can fully encapsulate the liquid, creating a robust and durable soft solid with superhydrophobic characteristics referred to as a liquid marble. Artificially created liquid marbles have been studied for about a decade but are already utilized in some hair and skin care products and have numerous other potential applications. These soft solids are usually formed in small quantity by depositing and rolling a drop of liquid on a layer of hydrophobic particles but can also be made in larger quantities in an industrial mixer. In this work, we demonstrate that microscale liquid marbles can also form through self-assembly during water condensation on a superhydrophobic surface covered with a loose layer of hydrophobic nanoparticles. Using in situ environmental scanning electron microscopy and optical microscopy, we study the dynamics of liquid marble formation and evaporation as well as their interaction with condensing water droplets. We demonstrate that the self-assembly of nanoparticle films into three-dimensional liquid marbles is driven by multiple coalescence events between partially covered droplets and is aided by surface flows causing rapid nanoparticle film redistribution. We also show that droplet and liquid marble coalescence can occur due to liquid-to-liquid contact or squeezing of the two objects into each other as a result of compressive forces from surrounding droplets and marbles. Irrelevant of the mechanism, coalescence of marbles and drops can cause their rapid movement across and rolling off the edge of the surface. We also demonstrate that the liquid marbles randomly moving across the surface can be captured and immobilized by hydrophilic surface patterns.
Dynamics and Matter-Wave Solitons in Bose-Einstein Condensates with Two- and Three-Body Interactions
Directory of Open Access Journals (Sweden)
Jing Chen
2014-01-01
Full Text Available By means of similarity transformation, this paper proposes the matter-wave soliton solutions and dynamics of the variable coefficient cubic-quintic nonlinear Schrödinger equation arising from Bose-Einstein condensates with time-dependent two- and three-body interactions. It is found that, under the effect of time-dependent two- and three-body interaction and harmonic potential with time-dependent frequency, the density of atom condensates will gradually diminish and finally collapse.
Crosta, M.
2012-04-10
We show that the perturbative nonlinearity associated with three-atom interactions, competing with standard two-body repulsive interactions, can change dramatically the evolution of one-dimensional (1D) dispersive shock waves in a Bose-Einstein condensate. In particular, we prove the existence of a rich crossover dynamics, ranging from the formation of multiple shocks regularized by nonlinear oscillations culminating in coexisting dark and antidark matter waves to 1D-soliton collapse. For a given scattering length, all these different regimes can be accessed by varying the density of atoms in the condensate.
Energy Technology Data Exchange (ETDEWEB)
Sakhel, Asaad R., E-mail: asaad.sakhel@fet.edu.jo [Department of Physics and Basic Sciences, Faculty of Engineering Technology, Balqa Applied University, Amman 11134 (Jordan); Abdus-Salam International Center for Theoretical Physics, Strada Costiera 11, 34151 Trieste (Italy)
2016-07-15
The dynamics of a Bose–Einstein condensate are examined numerically in the presence of a one-dimensional bichromatic optical lattice (BCOL) with external harmonic confinement in the strongly interacting regime. The condensate is excited by a focusing stirring red laser. Two realizations of the BCOL are considered, one with a rational and the other with an irrational ratio of the two constituting wave lengths. The system is simulated by the time-dependent Gross Pitaevskii equation that is solved using the Crank Nicolson method in real time. It is found that for a weak BCOL, the long-time averaged physical observables of the condensate respond only very weakly (or not at all) to changes in the secondary OL depth V{sub 1} showing that under these conditions the harmonic trap plays a dominant role in governing the dynamics. However, for a much larger strength of the BCOL, the response is stronger as it begins to compete with the external harmonic trap, such that the frequency of Bloch oscillations of the bosons rises with V{sub 1} yielding higher time-averages. Qualitatively there is no difference between the dynamics of the condensate resulting from the use of a rational or irrational ratio of the wavelengths since the external harmonic trap washes it out. It is further found that in the presence of an external harmonic trap, the BCOL acts in favor of superflow.
Energy Technology Data Exchange (ETDEWEB)
Hanai, Ryo; Littlewood, Peter B.; Ohashi, Yoji
2017-09-01
We present a stability analysis on a driven-dissipative electron-hole condensate in the BCS (Bardeen-Cooper-Schrieffer)-BEC (Bose-Einstein-condensation)-crossover region. Extending the combined BCS-Leggett theory with the generalized random phase approximation (GRPA) to the non-equilibrium case by employing the Keldysh formalism, we show that the pumping-and-decay of carriers causes a depairing effect on excitons. This phenomenon gives rise to an attractive interaction between excitons in the BEC regime, as well as a supercurrent that anomalously flows anti-parallel to ∇θ(r) (where θ(r) is the phase of the condensate) in the BCS regime, both leading to dynamical instabilities of an exciton-BEC.
International Nuclear Information System (INIS)
Gupta, Moumita; Dastidar, Krishna Rai
2009-01-01
We study the dynamics of the atomic and molecular Bose-Einstein condensates (BECs) of 87 Rb in a spherically symmetric trap coupled by stimulated Raman photoassociation process. Considering the higher order nonlinearity in the atom-atom interaction we analyze the dynamics of the system using coupled modified Gross-Pitaevskii (MGP) equations and compare it with mean-field coupled Gross-Pitaevskii (GP) dynamics. Considerable differences in the dynamics are obtained in these two approaches at large scattering length, i.e., for large values of peak-gas parameter x pk ≥10 -3 . We show how the dynamics of the coupled system is affected when the atom-molecule and molecule-molecule interactions are considered together with the atom-atom interaction and also when the strengths of these three interactions are increased. The effect of detuning on the efficiency of conversion of atomic fractions into molecules is demonstrated and the feasibility of maximum molecular BEC formation by varying the Raman detuning parameter at different values of time is explored. Thus by varying the Raman detuning and the scattering length for atom-atom interaction one can control the dynamics of the coupled atomic-molecular BEC system. We have also solved coupled Gross-Pitaevskii equations for atomic to molecular condensate formation through magnetic Feshbach resonance in a BEC of 85 Rb. We found similar features for oscillations between atomic and molecular condensates noted in previous theoretical study and obtained fairly good agreement with the evolution of total atomic condensate observed experimentally.
Camp, Piet
1985-01-01
The 1984 Advanced Study Institute on "Electronic Structure, Dynamics and Quantum Structural Properties of Condensed Matter" took place at the Corsendonk Conference Center, close to the City of Antwerpen, from July 16 till 27, 1984. This NATO Advanced Study Institute was motivated by the research in my Institute, where, in 1971, a project was started on "ab-initio" phonon calculations in Silicon. I~ is my pleasure to thank several instances and people who made this ASI possible. First of all, the sponsor of the Institute, the NATO Scientific Committee. Next, the co-sponsors: Agfa-Gevaert, Bell Telephone Mfg. Co. N.V., C & A, Esso Belgium·, CDC Belgium, Janssens Pharmaceutica, Kredietbank and the Scientific Office of the U.S. Army. Special thanks are due to Dr. P. Van Camp and Drs. H. Nachtegaele, who, over several months, prepared the practical aspects of the ASI with the secretarial help of Mrs. R.-M. Vandekerkhof. I also like to. thank Mrs. M. Cuyvers who prepared and organized the subject and material ...
Dynamic and energetic stabilization of persistent currents in Bose-Einstein condensates
Law, Kody
2014-05-09
We study conditions under which vortices in a highly oblate harmonically trapped Bose-Einstein condensate (BEC) can be stabilized due to pinning by a blue-detuned Gaussian laser beam, with particular emphasis on the potentially destabilizing effects of laser beam positioning within the BEC. Our approach involves theoretical and numerical exploration of dynamically and energetically stable pinning of vortices with winding number up to S=6, in correspondence with experimental observations. Stable pinning is quantified theoretically via Bogoliubov-de Gennes excitation spectrum computations and confirmed via direct numerical simulations for a range of conditions similar to those of experimental observations. The theoretical and numerical results indicate that the pinned winding number, or equivalently the winding number of the superfluid current about the laser beam, decays as a laser beam of fixed intensity moves away from the BEC center. Our theoretical analysis helps explain previous experimental observations and helps define limits of stable vortex pinning for future experiments involving vortex manipulation by laser beams.
DNA condensation by TmHU studied by optical tweezers, AFM and molecular dynamics simulations
Olbrich, Carsten; Brutzer, Hergen; Salomo, Mathias; Kleinekathöfer, Ulrich; Keyser, Ulrich F.; Kremer, Friedrich
2010-01-01
The compaction of DNA by the HU protein from Thermotoga maritima (TmHU) is analysed on a single-molecule level by the usage of an optical tweezers-assisted force clamp. The condensation reaction is investigated at forces between 2 and 40 pN applied to the ends of the DNA as well as in dependence on the TmHU concentration. At 2 and 5 pN, the DNA compaction down to 30% of the initial end-to-end distance takes place in two regimes. Increasing the force changes the progression of the reaction until almost nothing is observed at 40 pN. Based on the results of steered molecular dynamics simulations, the first regime of the length reduction is assigned to a primary level of DNA compaction by TmHU. The second one is supposed to correspond to the formation of higher levels of structural organisation. These findings are supported by results obtained by atomic force microscopy. PMID:22210966
Rabi dynamics of coupled atomic and molecular Bose-Einstein condensates
International Nuclear Information System (INIS)
Ishkhanyan, Artur; Chernikov, G.P.; Nakamura, Hiroki
2004-01-01
The dynamics of coherent Rabi oscillations in coupled atomic and molecular Bose-Einstein condensates is considered taking into account the atom-atom, atom-molecule, and molecule-molecule elastic interactions. The exact solution for the molecule formation probability is derived in terms of the elliptic functions. The two-dimensional space of the involved parameters intensity and detuning is analyzed and divided into two regions where the Rabi oscillations show different characteristics. A resonance curve is found, on which the molecular formation probability monotonically increases as a function of time. The maximum value of the final transition probability on this curve is 1/2 (i.e., total transition to the molecular state) and it is achieved at high field intensities starting from a minimal threshold defined by the interspecies interaction scattering lights. The explicit form of the resonance curve is determined, and it is shown that the resonance frequency position reveals a nonlinear dependence on the Rabi frequency of the applied field. A singular point is found on the resonance curve, where a power-law time evolution of the system is observed
Energy Technology Data Exchange (ETDEWEB)
Mamontov, Eugene [ORNL; O' Neill, Hugh Michael [ORNL
2014-01-01
Recent studies have outlined the use of eutectic solution of lithium chloride in water to study microscopic dynamics of lysozyme in an aqueous solvent that is remarkably similar to pure water in many respects, yet allows experiments over a wide temperature range without the solvent crystallization. The eutectic point in (H2O)R(LiCl) system corresponds to R 7.3, and it is of interest to investigate whether less concentrated aqueous solutions of LiCl could be employed in low-temperature studies of a solvated protein. We have investigated a range of concentrations of lysozyme and LiCl in aqueous solutions to identify systems that do not show phase separation and avoid solvent crystallization on cooling down. Compared to the lysozyme concentration in solution, the concentration of LiCl in the aqueous solvent plays the major role in determining systems suitable for low-temperature studies. We have observed interesting and rich phase behavior reminiscent of reentrant condensation of proteins.
Effect of Non-Condensable Gas on Cavity Dynamics and Sheet to Cloud Transition
Makiharju, Simo; Ganesh, Harish; Ceccio, Steven
2014-11-01
Partial cavitation occurs in numerous industrial and naval applications. Cavities on lifting surfaces, in cryogenic rocket motors or in fuel injectors can damage equipment and in general be detrimental to the system performance, especially as partial cavities can undergo auto-oscillation causing large pressure pulsations, unsteady loading of machinery and generate significant noise. In the current experiments incipient, intermittent cloud shedding and fully shedding cavities forming in the separated flow region downstream of a wedge were investigated. The Reynolds number based on hydraulic diameter was of the order of one million. Gas was injected directly into the cavitation region downstream of the wedge's apex or into the recirculating region such that with the same amount of injected gas less ended up in the shear layer. The cavity dynamics were studied with and without gas injection. The hypothesis to be tested were that i) relatively miniscule amounts of gas introduced into the shear layer at the cavity interface can reduce vapor production and ii) gas introduced into the separated region can dampen the auto oscillations. The authors also examined whether the presence of gas can switch the shedding mechanism from one dominated by condensation shock to one dominantly by re-entrant jet. The work was supported by ONR Grant Number N00014-11-1-0449.
A novel modelling approach for condensing boilers based on hybrid dynamical systems
Satyavada, H.; Baldi, S.
2016-01-01
Condensing boilers use waste heat from flue gases to pre-heat cold water entering the boiler. Flue gases are condensed into liquid form, thus recovering their latent heat of vaporization, which results in as much as 10%–12% increase in efficiency. Modeling these heat transfer phenomena is crucial to
Motion of condensates in non-Markovian zero-range dynamics
Hirschberg, Ori; Mukamel, David; Schütz, Gunter M.
2012-08-01
The condensation transition in a non-Markovian zero-range process is studied in one and higher dimensions. In the mean-field approximation, corresponding to infinite-range hopping, the model exhibits condensation with a stationary condensate, as in the Markovian case, but with a modified phase diagram. In the case of nearest-neighbor hopping, the condensate is found to drift by means of a ‘slinky’ motion from one site to the next. The mechanism of the drift is explored numerically in detail. A modified model with nearest-neighbor hopping which allows exact calculation of the steady state is introduced. The steady state of this model is found to be a product measure, and the condensate is stationary.
Motion of condensates in non-Markovian zero-range dynamics
International Nuclear Information System (INIS)
Hirschberg, Ori; Mukamel, David; Schütz, Gunter M
2012-01-01
The condensation transition in a non-Markovian zero-range process is studied in one and higher dimensions. In the mean-field approximation, corresponding to infinite-range hopping, the model exhibits condensation with a stationary condensate, as in the Markovian case, but with a modified phase diagram. In the case of nearest-neighbor hopping, the condensate is found to drift by means of a ‘slinky’ motion from one site to the next. The mechanism of the drift is explored numerically in detail. A modified model with nearest-neighbor hopping which allows exact calculation of the steady state is introduced. The steady state of this model is found to be a product measure, and the condensate is stationary. (paper)
Including dynamic CO2 intensity with demand response
International Nuclear Information System (INIS)
Stoll, Pia; Brandt, Nils; Nordström, Lars
2014-01-01
Hourly demand response tariffs with the intention of reducing or shifting loads during peak demand hours are being intensively discussed among policy-makers, researchers and executives of future electricity systems. Demand response rates have still low customer acceptance, apparently because the consumption habits requires stronger incentive to change than any proposed financial incentive. An hourly CO 2 intensity signal could give customers an extra environmental motivation to shift or reduce loads during peak hours, as it would enable co-optimisation of electricity consumption costs and carbon emissions reductions. In this study, we calculated the hourly dynamic CO 2 signal and applied the calculation to hourly electricity market data in Great Britain, Ontario and Sweden. This provided a novel understanding of the relationships between hourly electricity generation mix composition, electricity price and electricity mix CO 2 intensity. Load shifts from high-price hours resulted in carbon emission reductions for electricity generation mixes where price and CO 2 intensity were positively correlated. The reduction can be further improved if the shift is optimised using both price and CO 2 intensity. The analysis also indicated that an hourly CO 2 intensity signal can help avoid carbon emissions increases for mixes with a negative correlation between electricity price and CO 2 intensity. - Highlights: • We present a formula for calculating hybrid dynamic CO 2 intensity of electricity generation mixes. • We apply the dynamic CO 2 Intensity on hourly electricity market prices and generation units for Great Britain, Ontario and Sweden. • We calculate the spearman correlation between hourly electricity market price and dynamic CO 2 intensity for Great Britain, Ontario and Sweden. • We calculate carbon footprint of shifting 1 kWh load daily from on-peak hours to off-peak hours using the dynamic CO 2 intensity. • We conclude that using dynamic CO 2 intensity for
Nonequilibrium chiral fluid dynamics including dissipation and noise
International Nuclear Information System (INIS)
Nahrgang, Marlene; Herold, Christoph; Bleicher, Marcus; Leupold, Stefan
2011-01-01
We present a consistent theoretical approach for the study of nonequilibrium effects in chiral fluid dynamics within the framework of the linear σ model with constituent quarks. Treating the quarks as an equilibrated heat bath, we use the influence functional formalism to obtain a Langevin equation for the σ field. This allows us to calculate the explicit form of the damping coefficient and the noise correlators. For a self-consistent derivation of both the dynamics of the σ field and the quark fluid, we have to employ the 2PI (two-particle irreducible) effective action formalism. The energy dissipation from the field to the fluid is treated in the exact formalism of the 2PI effective action where a conserved energy-momentum tensor can be constructed. We derive its form and comment on approximations generating additional terms in the energy-momentum balance of the entire system.
International Nuclear Information System (INIS)
Vignolo, P.; Chiofalo, M.L.; Tosi, M.P.; Succi, Sauro
2002-01-01
We present a new numerical method for studying the dynamics of quantum fluids composed of a Bose-Einstein condensate and a cloud of bosonic or fermionic atoms in a mean-field approximation. The method combines an explicit time-marching algorithm, previously developed for Bose-Einstein condensates in a harmonic or optical-lattice potential, with a particle-in-cell approach to the equation of motion for the one-body Wigner distribution function in the cold-atom cloud. The method is tested against known analytical results on the free expansion of a fermion cloud from a cylindrical harmonic trap and is validated by examining how the expansion of the fermionic cloud is affected by the simultaneous expansion of a condensate. We then present original calculations on a condensate and a thermal cloud inside a harmonic well and a superposed optical lattice, by addressing the free expansion of the two components and their oscillations under an applied harmonic force. These results are discussed in the light of relevant theories and experiments
Alshaarawi, Amjad; Zhou, Kun; Scribano, Gianfranco; Attili, Antonio; Bisetti, Fabrizio; Clean Combustion Research Center Team
2013-11-01
The effect of residence time on the formation and growth of a condensating aerosol is simulated in a Hiemenz-type stagnation flow setup, for which a unique and well-defined time scale characterizes the velocity field. In this configuration, a hot stream saturated with dibutyle phthalate (DBP) vapor mixes with a cold dry stream. A mixing layer forms at the stagnation plane triggering supersaturation and droplets are generated by homogeneous nucleation. Aerosol dynamics are simulated using the Quadrature Method of Moments (QMOM). Two regimes related to the flow residence time are observed, i.e., a nucleation regime and a condensation regime. The nucleation regime, at short residence times, is characterized by the consumption of DBP vapor into droplets having a negligible effect on the vapor phase. In this regime, both the number density and volume fraction of droplets increase with residence time. In the condensation regime, at long residence times, vapor condensation consumes the vapor phase considerably. For longer residence times, more vapor is consumed, resulting in lower number densities due to the lower nucleation rates, whereas the volume fraction saturates.
Dynamic hysteresis modeling including skin effect using diffusion equation model
Energy Technology Data Exchange (ETDEWEB)
Hamada, Souad, E-mail: souadhamada@yahoo.fr [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Louai, Fatima Zohra, E-mail: fz_louai@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Nait-Said, Nasreddine, E-mail: n_naitsaid@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Benabou, Abdelkader, E-mail: Abdelkader.Benabou@univ-lille1.fr [L2EP, Université de Lille1, 59655 Villeneuve d’Ascq (France)
2016-07-15
An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.
International Nuclear Information System (INIS)
Rey, Ana Maria; Hu, B.L.; Roura, Albert; Calzetta, Esteban; Clark, Charles W.
2004-01-01
In this work a two-particle irreducible (2PI) closed-time-path (CTP) effective action is used to describe the nonequilibrium dynamics of a Bose-Einstein condensate selectively loaded into every third site of a one-dimensional optical lattice. The motivation of this work is the recent experimental realization of this system. Patterned loading methods may be useful for quantum computing with trapped atoms. This system also serves to illustrate many basic issues in nonequilibrium quantum-field theory pertaining to the dynamics of quantum correlations and fluctuations which goes beyond the capability of a mean-field theory. By numerically evolving in time the initial-state configuration using the Bose-Hubbard Hamiltonian an exact quantum solution is available for this system in the case of few atoms and wells. One can also use it to test various approximate methods. Under the 2PI CTP scheme with this initial configuration, three different approximations are considered: (a) the Hartree-Fock-Bogoliubov (HFB) approximation (b) the next-to-leading-order 1/N expansion of the 2PI effective action up to second order in the interaction strength, and (c) a second-order perturbative expansion in the interaction strength. We present detailed comparisons between these approximations and determine their range of validity by contrasting them with the exact many-body solution for a moderate number of atoms and wells. As a general feature we observe that because the second-order 2PI approximations include multiparticle scattering in a systematic way, they are able to capture damping effects exhibited in the exact solution, which a mean-field collisionless approach fails to produce. While the second-order approximations show a clear improvement over the HFB approximation, our numerical results show that they fail at late times, when interaction effects are significant
Phase separation and dynamics of two-component Bose-Einstein condensates
DEFF Research Database (Denmark)
Lee, Kean Loon; Jørgensen, Nils Byg; Liu, I-Kang
2016-01-01
The miscibility of two interacting quantum systems is an important testing ground for the understanding of complex quantum systems. Two-component Bose-Einstein condensates enable the investigation of this scenario in a particularly well controlled setting. In a homogeneous system, the transition...... critically on atom numbers. We demonstrate how monitoring of damping rates and frequencies of dipole oscillations enables the experimental mapping of the phase diagram by numerical implementation of a fully self-consistent finite-temperature kinetic theory for binary condensates. The change in damping rate...
Dynamics of Phase Coherence Onset in Bose Condensates of Photons by Incoherent Phonon Emission
Snoke, D. W.; Girvin, S. M.
2013-04-01
Recent experiments with photons equilibrating inside a dye medium in a cavity have raised the question of whether Bose condensation can occur in a system with only incoherent interaction with phonons in a bath but without particle-particle interaction. Analytical calculations analogous to those done for a system with particle-particle interactions indicate that a system of bosons interacting only with incoherent phonons can indeed undergo Bose condensation and furthermore can exhibit spontaneous amplification of quantum coherence. We review the basic theory for these calculations.
Bao, Weizhu
2013-01-01
We propose a simple, efficient, and accurate numerical method for simulating the dynamics of rotating Bose-Einstein condensates (BECs) in a rotational frame with or without longrange dipole-dipole interaction (DDI). We begin with the three-dimensional (3D) Gross-Pitaevskii equation (GPE) with an angular momentum rotation term and/or long-range DDI, state the twodimensional (2D) GPE obtained from the 3D GPE via dimension reduction under anisotropic external potential, and review some dynamical laws related to the 2D and 3D GPEs. By introducing a rotating Lagrangian coordinate system, the original GPEs are reformulated to GPEs without the angular momentum rotation, which is replaced by a time-dependent potential in the new coordinate system. We then cast the conserved quantities and dynamical laws in the new rotating Lagrangian coordinates. Based on the new formulation of the GPE for rotating BECs in the rotating Lagrangian coordinates, a time-splitting spectral method is presented for computing the dynamics of rotating BECs. The new numerical method is explicit, simple to implement, unconditionally stable, and very efficient in computation. It is spectral-order accurate in space and second-order accurate in time and conserves the mass on the discrete level. We compare our method with some representative methods in the literature to demonstrate its efficiency and accuracy. In addition, the numerical method is applied to test the dynamical laws of rotating BECs such as the dynamics of condensate width, angular momentum expectation, and center of mass, and to investigate numerically the dynamics and interaction of quantized vortex lattices in rotating BECs without or with the long-range DDI.Copyright © by SIAM.
Weiss, M.; Dittmar, L.; Junginger, H.M.; Patel, M.K.; Blok, K.
2009-01-01
High costs often prevent the market diffusion of novel and efficient energy technologies. Monitoring cost and price decline for these technologies is thus important in order to establish effective energy policy. Here, we present experience curves and cost-benefit analyses for condensing gas boilers
International Nuclear Information System (INIS)
Abdullaev, F.Kh.; Kamchatnov, A.M.; Konotop, V.V.; Brazhnyi, V.A.
2003-01-01
Evolution of periodic matter waves in one-dimensional Bose-Einstein condensates with time-dependent scattering length is described. It is shown that variation of the effective nonlinearity is a powerful tool for controlled generation of bright and dark solitons starting with periodic waves
Aeroelastic modal dynamics of wind turbines including anisotropic effects
Energy Technology Data Exchange (ETDEWEB)
Fisker Skjoldan, P.
2011-03-15
Several methods for aeroelastic modal analysis of a rotating wind turbine are developed and used to analyse the modal dynamics of two simplified models and a complex model in isotropic and anisotropic conditions. The Coleman transformation is used to enable extraction of the modal frequencies, damping, and periodic mode shapes of a rotating wind turbine by describing the rotor degrees of freedom in the inertial frame. This approach is valid only for an isotropic system. Anisotropic systems, e.g., with an unbalanced rotor or operating in wind shear, are treated with the general approaches of Floquet analysis or Hill's method which do not provide a unique reference frame for observing the modal frequency, to which any multiple of the rotor speed can be added. This indeterminacy is resolved by requiring that the periodic mode shape be as constant as possible in the inertial frame. The modal frequency is thus identified as the dominant frequency in the response of a pure excitation of the mode observed in the inertial frame. A modal analysis tool based directly on the complex aeroelastic wind turbine code BHawC is presented. It uses the Coleman approach in isotropic conditions and the computationally efficient implicit Floquet analysis in anisotropic conditions. The tool is validated against system identifications with the partial Floquet method on the nonlinear BHawC model of a 2.3 MW wind turbine. System identification results show that nonlinear effects on the 2.3 MW turbine in most cases are small, but indicate that the controller creates nonlinear damping. In isotropic conditions the periodic mode shape contains up to three harmonic components, but in anisotropic conditions it can contain an infinite number of harmonic components with frequencies that are multiples of the rotor speed. These harmonics appear in calculated frequency responses of the turbine. Extreme wind shear changes the modal damping when the flow is separated due to an interaction between
Dynamic Analysis of Wind Turbines Including Soil-Structure Interaction
DEFF Research Database (Denmark)
Harte, M.; Basu, B.; Nielsen, Søren R.K.
2012-01-01
blades and includes the effect of centrifugal stiffening due to rotation. The foundation of the structure is modeled as a rigid gravity based foundation with two DOF whose movement is related to the surrounding soil by means of complex impedance functions generated using cone model. Transfer functions...... for displacement of the turbine system are obtained and the modal frequencies of the combined turbine-foundation system are estimated. Simulations are presented for the MDOF turbine structure subjected to wind loading for different soil stiffness conditions. Steady state and turbulent wind loading, developed using...... blade element momentum theory and the Kaimal spectrum, have been considered. Soil stiffness and damping properties acquired from DNV/Risø standards are used as a comparison. The soil-structure interaction is shown to affect the response of the wind turbine. This is examined in terms of the turbine...
Condensation-induced kinematics and dynamics of cyclones, hurricanes and tornadoes
International Nuclear Information System (INIS)
Makarieva, A.M.; Gorshkov, V.G.
2009-01-01
A universal equation is obtained for air pressure and wind velocity in cyclones, hurricanes and tornadoes as dependent on the distance from the center of the considered wind pattern driven by water vapor condensation. The obtained theoretical estimates of the horizontal profiles of air pressure and wind velocity, eye and wind wall radius in hurricanes and tornadoes and maximum values of the radial, tangential and vertical velocity components are in good agreement with empirical evidence.
Study of the Condensed Matter Dynamics by the Deep Inelastic Neutron Technique
International Nuclear Information System (INIS)
Blostein, Juan Jeronimo
2004-01-01
In this work we describe the motivations that originated the eVS technique, and we explain why this technique is particularly useful to study the dynamics of nuclei in different systems.We expose the fundamentals of the convolution formalism usually employed for the data treatment of this technique, which is based on the assumption that the energy of the detected neutrons is fixed by the resonant filter. In this thesis it is presented for the first time the exact formalism that describes the experimentally obtained spectra for thin samples, which considers all pairs of initial and final energies compatible with the flight paths, in clear contrast with the mentioned hypothesis of fixed final energy .In the light of the exact formalism, the analysis presented in the this thesis reveals flaws in the convolution formalism employed for the experimental data treatment.This analysis shows that the deficient descriptions of the different peaks observed in the time of flight scale produce errors in the magnitudes usually informed as results of an eVS experiment, i.e.: intensity of isolated peaks, intensities of peaks not totally resolved, effective temperatures and momentum distributions.To expose the basic reason of such deficiencies, an the exact formalism is employed to analyze the final energy distributions responsible of the observed intensities in the different time channels.We conclude that for each time channel, it is not a well-defined energy, but a whole energy distribution the responsible to produce the observed spectrum.We show that such energy distributions are not determined only by the filter's resonance, but depend strongly on the time of flight due to kinematic and dynamic reasons, not taken into account in the usual data treatment.We analyze examples where the use of the convolution approximation leads to erroneous results, and we show them to have a similar behavior than claimed anomalous results published in several papers, which ascribe them to new
International Nuclear Information System (INIS)
Zhang Chunyi; Gao Yitian; Meng Xianghua; Li Juan; Xu Tao; Wei Guangmei; Zhu Hongwu
2006-01-01
The phenomena of the trapped Bose-Einstein condensates related to matter waves and nonlinear atom optics can be governed by a variable-coefficient Korteweg-de Vries (vc-KdV) model with additional terms contributed from the inhomogeneity in the axial direction and the strong transverse confinement of the condensate, and such a model can also be used to describe the water waves propagating in a channel with an uneven bottom and/or deformed walls. In this paper, with the help of symbolic computation, the bilinear form for the vc-KdV model is obtained and some exact solitonic solutions including the N-solitonic solution in explicit form are derived through the extended Hirota method. We also derive the auto-Baecklund transformation, nonlinear superposition formula, Lax pairs and conservation laws of this model. Finally, the integrability of the variable-coefficient model and the characteristic of the nonlinear superposition formula are discussed
Indekeu, Joseph O.; Van Thu, Nguyen; Lin, Chang-You; Phat, Tran Huu
2018-04-01
The localized low-energy interfacial excitations, or interfacial Nambu-Goldstone modes, of phase-segregated binary mixtures of Bose-Einstein condensates are investigated analytically. To this end a double-parabola approximation (DPA) is performed on the Lagrangian density in Gross-Pitaevskii theory for a system in a uniform potential. This DPA entails a model in which analytic expressions are obtained for the excitations underlying capillary waves or ripplons for arbitrary strength K (>1 ) of the phase segregation. The dispersion relation ω (k ) ∝k3 /2 is derived directly from the Bogoliubov-de Gennes equations in the limit that the wavelength 2 π /k is much larger than the interface width. The proportionality constant in the dispersion relation provides the static interfacial tension. A correction term in ω (k ) of order k5 /2 is calculated analytically within the DPA model. The combined result is tested against numerical diagonalization of the exact Bogoliubov-de Gennes equations. Satisfactory agreement is obtained in the range of physically relevant wavelengths. The ripplon dispersion relation is relevant to state-of-the-art experiments using (quasi)uniform optical-box traps. Furthermore, within the DPA model explicit expressions are obtained for the structural deformation of the interface due to the passing of the capillary wave. It is found that the amplitude of the wave is enhanced by an amount that is quadratic in the ratio of the phase velocity ω /k to the sound velocity c . For generic mixtures consisting of condensates with unequal healing lengths, an additional modulation is predicted of the common value of the condensate densities at the interface.
Soliton dynamics for trapped Bose-Einstein condensate with higher-order interaction
Directory of Open Access Journals (Sweden)
Ying Wang
2017-08-01
Full Text Available We model the three-dimensional (3D trapped Bose-Einstein condensate with the Gross-Pitaevskii equation (GPE incorporating higher-order nonlinear interaction effects. Based on the F-expansion method and self-similar approach, we analytically derive the exact soliton solutions of the 3D GPE, identifying the oscillatory mode under certain experimental settings. The oscillatory kinetic parameter values we obtained coincide very well with those reported in previous work, which is based on the variational approach, showing the applicability of the theoretical treatment presented in this work.
Synchronization and Stabilization of Chaotic Dynamics in a Quasi-1D Bose-Einstein Condensate
Directory of Open Access Journals (Sweden)
B. A. Idowu
2013-01-01
Full Text Available A nonlinear control is proposed for the exponential stabilization and synchronization of chaotic behaviour in a model of Bose-Einstein condensate (BEC. The active control technique is designed based on Lyapunov stability theory and Routh-Hurwitz criteria. The control design approach in both cases guarantees the stability of the controlled states. Whereas the synchronization of two identical BEC in their chaotic states can be realized using the scheme; a suitable controller is also capable of driving the otherwise chaotic oscillation to a stable state which could be expected in practice. The effectiveness of this technique is theoretically and numerically demonstrated.
Gluon transport equation with effective mass and dynamical onset of Bose–Einstein condensation
International Nuclear Information System (INIS)
Blaizot, Jean-Paul; Jiang, Yin; Liao, Jinfeng
2016-01-01
We study the transport equation describing a dense system of gluons, in the small scattering angle approximation, taking into account medium-generated effective masses of the gluons. We focus on the case of overpopulated systems that are driven to Bose–Einstein condensation on their way to thermalization. The presence of a mass modifies the dispersion relation of the gluon, as compared to the massless case, but it is shown that this does not change qualitatively the scaling behavior in the vicinity of the onset.
Condensation in insulated homes
Energy Technology Data Exchange (ETDEWEB)
Wiley, R A
1978-05-28
A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)
Condensate of massive graviton and dark matter
Aoki, Katsuki; Maeda, Kei-ichi
2018-01-01
We study coherently oscillating massive gravitons in the ghost-free bigravity theory. This coherent field can be interpreted as a condensate of the massive gravitons. We first define the effective energy-momentum tensor of the coherent massive gravitons in a curved spacetime. We then study the background dynamics of the universe and the cosmic structure formation including the effects of the coherent massive gravitons. We find that the condensate of the massive graviton behaves as a dark matt...
Knight, Chris; Maupin, C Mark; Izvekov, Sergei; Voth, Gregory A
2010-10-12
In this report, a general methodology is presented for the parametrization of a reactive force field using data from a condensed phase ab initio molecular dynamics (AIMD) simulation. This algorithm allows for the creation of an empirical reactive force field that accurately reproduces the underlying ab initio reactive surface while providing the ability to achieve long-time statistical sampling for large systems not possible with AIMD alone. In this work, a model for the hydrated excess proton is constructed where the hydronium cation and proton hopping portions of the model are statistically force-matched to the results of Car-Parrinello Molecular Dynamics (CPMD) simulations. The flexible nature of the algorithm also allows for the use of the more accurate classical simple point-charge flexible water (SPC/Fw) model to describe the water-water interactions while utilizing the ab initio data to create an overall multistate molecular dynamics (MS-MD) reactive model of the hydrated excess proton in water. The resulting empirical model for the system qualitatively reproduces thermodynamic and dynamic properties calculated from the ab initio simulation while being in good agreement with experimental results and previously developed multistate empirical valence bond (MS-EVB) models. The present methodology, therefore, bridges the AIMD technique with the MS-MD modeling of reactive events, while incorporating key strengths of both.
Tunneling dynamics of Bose—Einstein condensates with higher-order interactions in optical lattice
Tie, Lu; Xue, Ju-Kui
2011-12-01
The nonlinear Landau—Zener tunneling and nonlinear Rabi oscillations of Bose—Einstein condensate (BEC) with higher-order atomic interaction between the Bloch bands in an accelerating optical lattice are discussed. Within the two-level model, the tunneling probability of BEC with higher-order atomic interaction between Bloch bands is obtained. We finds that the tunneling rate is closely related to the higher-order atomic interaction. Furthermore, the nonlinear Rabi oscillations of BEC with higher-order atomic interaction between the bands are discussed by imposing a periodic modulation on the level bias. Analytical expressions of the critical higher-order atomic interaction for suppressing/enhancing the Rabi oscillations are obtained. It is shown that the critical value strongly depends on the modulation parameters (i.e., the modulation amplitude and frequency) and the strength of periodic potential.
Ge, Ni-Na; Wei, Yong-Kai; Zhao, Feng; Chen, Xiang-Rong; Ji, Guang-Fu
2014-07-01
The electronic structure and initial decomposition in high explosive HMX under conditions of shock loading are examined. The simulation is performed using quantum molecular dynamics in conjunction with multi-scale shock technique (MSST). A self-consistent charge density-functional tight-binding (SCC-DFTB) method is adapted. The results show that the N-N-C angle has a drastic change under shock wave compression along lattice vector b at shock velocity 11 km/s, which is the main reason that leads to an insulator-to-metal transition for the HMX system. The metallization pressure (about 130 GPa) of condensed-phase HMX is predicted firstly. We also detect the formation of several key products of condensed-phase HMX decomposition, such as NO2, NO, N2, N2O, H2O, CO, and CO2, and all of them have been observed in previous experimental studies. Moreover, the initial decomposition products include H2 due to the C-H bond breaking as a primary reaction pathway at extreme condition, which presents a new insight into the initial decomposition mechanism of HMX under shock loading at the atomistic level.
Gotlibovych, Igor; Schmidutz, Tobias F.; Gaunt, Alexander L.; Navon, Nir; Smith, Robert P.; Hadzibabic, Zoran
2014-06-01
We study the properties of an atomic Bose-Einstein condensate produced in an optical-box potential, using high-resolution Bragg spectroscopy. For a range of box sizes, up to 70μm, we directly observe Heisenberg-limited momentum uncertainty of the condensed atoms. We measure the condensate interaction energy with a precision of kB×100 pK and study, both experimentally and numerically, the dynamics of its free expansion upon release from the box potential. All our measurements are in good agreement with theoretical expectations for a perfectly homogeneous condensate of spatial extent equal to the size of the box, which also establishes the uniformity of our optical-box system on a sub-nK energy scale.
Modelling of condensation phenomena
International Nuclear Information System (INIS)
Jeong, Jae Jun; Chang, Won Pyo
1996-07-01
Condensation occurs when vapor is cooled sufficiently below the saturation temperature to induce the nucleation of droplets. Such nucleation may occur homogeneously within the vapor or heterogeneously on entrained particular matter. Heterogeneous nucleation may occur on the walls of the system, where the temperature is below the saturation temperature. There are two forms of heterogeneous condensation, drop-wise and film-wise. Another form of condensation occurs when vapor directly contacts to subcooled liquid. In nuclear power plant systems, all forms of condensation may occur during normal operation or accident conditions. In this work the modelling of condensation is surveyed, including the Nusselts' laminar film condensation theory in 1916, Rohsenow's turbulent film condensation model in 1950s, and Chen's models in 1987. Major attention is paid on the film condensation models among various research results because of its importance in engineering applications. It is found that theory, experiment, and empirical correlations for film condensation are well established, but research for drop-wise and direct-contact condensation are not sufficient yet. Condensation models in the best-estimate system codes such as RELAP5/MOD3 and CATHARE2 are also investigated. 3 tabs., 11 figs., 36 refs. (Author)
International Nuclear Information System (INIS)
Chen Yan; Chen Yong; Zhang Kezhi
2009-01-01
We study the dynamic behaviour of Bose-Einstein condensates with two- and three-atom interactions in optical lattices with analytical and numerical methods. It is found that the steady-state relative population displays tuning-fork bifurcation when the system parameters are changed to certain critical values. In particular, the existence of the three-body interaction not only transforms the bifurcation point of the system but also greatly affects the macroscopic quantum self-trapping behaviours associated with the critically stable steady-state solution. In addition, we investigated the influence of the initial conditions, three-body interaction, and the energy bias on the macroscopic quantum self-trapping. Finally, by applying the periodic modulation on the energy bias, we observed that the relative population oscillation exhibits a process from order to chaos, via a series of period-doubling bifurcations.
Simple Simulations of DNA Condensation
Energy Technology Data Exchange (ETDEWEB)
STEVENS,MARK J.
2000-07-12
Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.
Ge, Ni-Na; Wei, Yong-Kai; Ji, Guang-Fu; Chen, Xiang-Rong; Zhao, Feng; Wei, Dong-Qing
2012-11-26
We have performed quantum-based multiscale simulations to study the initial chemical processes of condensed-phase octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under shock wave loading. A self-consistent charge density-functional tight-binding (SCC-DFTB) method was employed. The results show that the initial decomposition of shocked HMX is triggered by the N-NO(2) bond breaking under the low velocity impact (8 km/s). As the shock velocity increases (11 km/s), the homolytic cleavage of the N-NO(2) bond is suppressed under high pressure, the C-H bond dissociation becomes the primary pathway for HMX decomposition in its early stages. It is accompanied by a five-membered ring formation and hydrogen transfer from the CH(2) group to the -NO(2) group. Our simulations suggest that the initial chemical processes of shocked HMX are dependent on the impact velocity, which gain new insights into the initial decomposition mechanism of HMX upon shock loading at the atomistic level, and have important implications for understanding and development of energetic materials.
Doute, S.; Lopes-Gautier, R.; Smythe, W. D.; Kamp, L. W.; Carlson, R.
2001-01-01
Near Infrared Mapping Spectrometer data acquired during the I24, 25, and 27 Io's Fly-bys by Galileo are analyzed to map the SO2 frost abundance and granularity. This allows a better understanding of the dynamics and evolution of gas condensation around volcanic plumes. Additional information is contained in the original extended abstract.
Proceedings: Condenser technology conference
International Nuclear Information System (INIS)
Tsou, J.L.; Mussalli, Y.G.
1991-08-01
Seam surface condenser and associated systems performance strongly affects availability and heat rate in nuclear and fossil power plants. Thirty-six papers presented at a 1990 conference discuss research results, industry experience, and case histories of condenser problems and solutions. This report contains papers on life extension, performance improvement, corrosion and failure analysis, fouling prevention, and recommendation for future R ampersand D. The information represents recent work on condenser problems and solutions to improve the procurement, operation, and maintenance functions of power plant personnel. Several key points follow: A nuclear and a fossil power plant report show that replacing titanium tube bundles improves condenser availability and performance. One paper reports 10 years of experience with enhanced heat transfer tubes in utility condensers. The newly developed enhanced condenser tubes could further improve condensing heat transfer. A new resistance summation method improves the accuracy of condenser performance prediction, especially for stainless steel and titanium tubed condensers. Several papers describe improved condenser fouling monitoring techniques, including a review of zebra mussel issues
Czech Academy of Sciences Publication Activity Database
Buchholz, M.; Goletz, Ch. M.; Grossman, F.; Schmidt, B.; Heyda, J.; Jungwirth, Pavel
2012-01-01
Roč. 116, č. 46 (2012), s. 11199-11210 ISSN 1089-5639 R&D Projects: GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : semiclassical molecular dynamics * cluster * wavepacket * coherence * spectra Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.771, year: 2012
International Nuclear Information System (INIS)
Liu, Chao-Fei; Lu, Min; Liu, Wei-Qing
2012-01-01
The Rabi coupling between two components of Bose–Einstein condensates is used to controllably change ordinary dark soliton into dynamic vector dark soliton or ordinary vector dark soliton. When all inter- and intraspecies interactions are equal, the dynamic vector dark soliton is exactly constructed by two sub-dark-solitons, which oscillate with the same velocity and periodically convert with each other. When the interspecies interactions deviate from the intraspecies ones, the whole soliton can maintain its essential shape, but the sub-dark-soliton becomes inexact or is broken. This study indicates that the Rabi coupling can be used to obtain various vector dark solitons. -- Highlights: ► We consider the Rabi coupling to affect the dark soliton in BECs. ► We examine the changes of the initial dark solitons. ► The structure of the soliton depends on the inter- and intraspecies interactions strength. ► The Rabi coupling can be used to obtain various vector dark solitons.
Daub, Christopher D; Cann, Natalie M
2012-11-01
We study small clusters of water or methanol containing a single Ca(2+), Na(+), or Cl(-) ion with classical molecular dynamics simulations, using models that incorporate polarizability via the Drude oscillator framework. Evaporation and condensation of solvent from these clusters is examined in two systems, (1) for isolated clusters initially prepared at different temperatures and (2) those with a surrounding inert (Ar) gas of varying temperature. We examine these clusters over a range of sizes, from almost bare ions up to 40 solvent molecules. We report data on the evaporation and condensation of solvent from the clusters and argue that the observed temperature dependence of evaporation in the smallest clusters demonstrates that the presence of heated gas alone cannot, in most cases, solely account for bare ion production in electrospray ionization (ESI), neglecting the key contribution of the electric field. We also present our findings on the structure and energetics of the clusters as a function of size. Our data agree well with the abundant literature on hydrated ion clusters and offer some novel insight into the structure of methanol and ion clusters, especially those with a Cl(-) anion, where we observe the presence of chain-like structures of methanol molecules. Finally, we provide some data on the reparameterizations necessary to simulate ions in methanol using the separately developed Drude oscillator models for methanol and for ions in water.
International Nuclear Information System (INIS)
Aldiyarov, A.; Aryutkina, M.; Drobyshev, A.; Kaikanov, M.; Kurnosov, V.
2009-01-01
An IR spectrometric investigation of the dynamic glass transition of ethanol from the rotationally disordered crystal to the orientationally disordered crystal is carried out. The samples considered are thin films formed from the gas phase at a substrate temperature of T=16 K. The measurements are performed using the experimental apparatus which has been described in detail in our recent work. The sample thickness was d=2 μm, and the typical rate of annealing is approximately 10 K/min. The results are compared with the phase diagram of solid ethanol proposed by M.A. Ramos et al. We observe good agreement between the temperature intervals of existence of the amorphous and crystalline states. The low-temperature amorphous phase (12-70 K) is described by the present authors as amorphous solid ethanol by analogy with the amorphous solid water
Orville, Harold D.; Chen, Jeng-Ming
1982-12-01
This study attempts to isolate the dynamic and microphysical effects of seeding. A two-dimensional, time-dependent cloud model has been used to simulate silver iodide (AgI) seeding of convective clouds. Two major dynamic effects (latent heat of fusion and condensate loading) are separated through a sequence of differential processes to examine their individual effect. A High Plains sounding is used for the tests.The effects of condensate loading and latent heat of fusion are due to natural processes as well as to cloud seeding. Separate discussions and comparisons are made of both processes. Condensate loading has the greater influence on cloud development.A method of differencing the results from different cases is used to illustrate the overall seeding effects and to isolate those portions of the latent heat of fusion and loading effects which are due solely to ice-phase cloud seeding. The results indicate significant fusion and loading effects due to seeding, but at 10 min or so after the seeding. Glaciation via accretional freezing of the cloud water is accomplished at this time. Direct seeding glaciation of this vigorous cloud within a minute or so of seeding time is not accomplished.The model results show a natural cloud system that consists of three cloud cycles during the period of integration (covering a real-time period of about one hour). The first cloud cycle is produced by a model thermal and humidity perturbation, the two second-cycle clouds are set off by the acceleration stage of the first cloud, and the third-cycle clouds are initiated by downdraft outflow induced by falling precipitation in the boundary layer. Major cloud growth and precipitation formation are caused by interactions of the second-cycle clouds with the first cloud.The seeded cloud system, although identical to the unseeded system until seeding is simulated (at 19 min of simulated real-time), forms precipitation earlier than the unseeded system and produces four cloud cycles during
Advances in studying order and dynamics in condensed matter by NMR
Energy Technology Data Exchange (ETDEWEB)
Voda, M.A.
2006-07-13
In this thesis, molecular transport in liquid samples is studied in terms of susceptibility induced magnetic field inhomogeneities and spectral distortions for interdiffusion in binary mixtures. Molecular order and dynamics are topics for two different soft solids, natural rubber and polyurethane. The influence of the mixture heterogeneity on the magnetic field homogeneity was investigated in terms of a spatial and time-dependent magnetic susceptibility. The effect of the heterogeneous distribution of magnetic susceptibility in liquid mixtures on the static and rf field homogeneity was simulated together with the corresponding spectral distortions. The problem of low magnetic field homogeneity provided by the Halbach type of magnets is discussed. The design of modified Halbach magnets is studied in order to increase the field homogeneity. The work was focused on two types of Halbach magnets, consisting of 16 and 24 magnet blocks, respectively. Different modifications were applied to these magnet designs, and the field homogeneity was significantly improved. The changes induced in molecular dynamics and order in stretched elastomers was investigated using multispin moments edited by multiple-quantum NMR. The main purpose of this part is to investigate the changes in proton residual dipolar coupling and the sensitivity of multiple quantum coherences of higher order for cross-linked natural rubber under uniaxial deformation. The effect of uniaxial deformation of a natural rubber band was investigated by measurements of second van Vleck moments and fourth moments edited by double-quantum and triple-quantum coherences, respectively. A spin diffusion experiment was employed for the elucidation of the morphology and domain sizes of a series of polyurethane samples. A proton DQ dipolar filer was used to select the magnetization of the rigid phase. The most probable morphology is three-dimensional for the TPU samples with a high content in HS as was established by a
Advances in studying order and dynamics in condensed matter by NMR
International Nuclear Information System (INIS)
Voda, M.A.
2006-01-01
In this thesis, molecular transport in liquid samples is studied in terms of susceptibility induced magnetic field inhomogeneities and spectral distortions for interdiffusion in binary mixtures. Molecular order and dynamics are topics for two different soft solids, natural rubber and polyurethane. The influence of the mixture heterogeneity on the magnetic field homogeneity was investigated in terms of a spatial and time-dependent magnetic susceptibility. The effect of the heterogeneous distribution of magnetic susceptibility in liquid mixtures on the static and rf field homogeneity was simulated together with the corresponding spectral distortions. The problem of low magnetic field homogeneity provided by the Halbach type of magnets is discussed. The design of modified Halbach magnets is studied in order to increase the field homogeneity. The work was focused on two types of Halbach magnets, consisting of 16 and 24 magnet blocks, respectively. Different modifications were applied to these magnet designs, and the field homogeneity was significantly improved. The changes induced in molecular dynamics and order in stretched elastomers was investigated using multispin moments edited by multiple-quantum NMR. The main purpose of this part is to investigate the changes in proton residual dipolar coupling and the sensitivity of multiple quantum coherences of higher order for cross-linked natural rubber under uniaxial deformation. The effect of uniaxial deformation of a natural rubber band was investigated by measurements of second van Vleck moments and fourth moments edited by double-quantum and triple-quantum coherences, respectively. A spin diffusion experiment was employed for the elucidation of the morphology and domain sizes of a series of polyurethane samples. A proton DQ dipolar filer was used to select the magnetization of the rigid phase. The most probable morphology is three-dimensional for the TPU samples with a high content in HS as was established by a
Dynamical friction in condensed matter. Progress report, April 15, 1982-December 15, 1982
International Nuclear Information System (INIS)
Sokoloff, J.B.; Perry, C.H.
1982-12-01
We have performed molecular dynamical calculations on a model for sliding charge density waves interacting with impurities, in order to understand the narrow band noise spectrum and metastability observed in niobium triselenate. We have also studied localization of electron and phonon states due to incommensurability in crystals containing two incommensurate periodic potentials such as crystals with charge density waves and ionic conductors. We are presently considering localization in the electron in a magnetic field and a periodic potential problem, which maps into the problem of an electron in two incommensurate periodic potentials discussed in the last sentence. ir, Raman, inelastic and quasi-elastic neutron scattering studies of ZrO 2 -Y 2 O 3 have been measured on samples with 0,3,4,9,12,16, and 20 weight percent yttria have been completed as a function of temperature from 10 to 1700 0 K. Their ir and Raman active frequencies, oscillator strengths and life-times have been obtained from the data. These studies also provided values for the temperature dependent oxygen-vacancy self diffusion constant, hopping times, activation energies and conductivities. The temperature dependence of the elastic constants C 11 , C 12 and C 14 , the lattice parameter and the static dielestic constant for cubic zirconia were measured from the neutron and ir data. Polarized ir and Raman light scattering studies of the one dimensional conductor hollandite K/sub 1.7/Mg/sub 0.85/Ti/sub 7.15/O 16 have been undertaken. Measurements have also been made down to 10 0 K and up to 1000 0 K
Quartet condensation of fermions.
Talukdar, Aseem; Ma, Michael; Zhang, Fu-Chun
2007-10-01
We investigate quartet condensation in fermion systems with four internal states. This is the generalization of the well known BCS superconductor formed by Cooper pair (CP) condensation. Physical examples include spin-3/2 fermionic atoms, bi-layered systems with electrons and holes, quadra-layer spin polarized electron hole system, and two band electronic system. We derive the Landau Ginzberg (LG) free energy for such system in terms of the CP amplitudes. The LG free energy is found to contain attractive interactions among different types of CP's. This will allow them to form bound states of CP's called Cooper quartets (CQ). Using a variational calculation based on the Bogoliubov inequality, we find that CQ condensation may be favored over pair condensation at low temperature. We also study the pairing structures in such systems when pair condensation is preferred.
International Nuclear Information System (INIS)
Masuda, Fujio
1980-01-01
Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)
Bracegirdle, Ann; Clayden, Jonathan; Lai, Lai Wah
2008-01-01
Summary Atropisomeric biaryl aldehydes undergo diastereoselective condensation with (?)-ephedrine and with a proline-derived diamine, with selectivity highly dependent on solvent, temperature and reaction conditions. Levels of thermodynamic control up to 5:1 may be obtained by heating the diamine with the aldehyde in a sealed tube. Alternatively, crystallisation-induced dynamic transformation allows isolation of a single diastereoisomer in up to 85% yield. Hydrolysis and reduction of the majo...
Singh, Badri Nath; Achary, V Mohan Murali; Panditi, Varakumar; Sopory, Sudhir K; Reddy, Malireddy K
2017-08-01
The topoisomerase II expression varies as a function of cell proliferation. Maximal topoisomerase II expression was tightly coupled to S phase and G2/M phase via both transcriptional and post-transcriptional regulation. Investigation in meiosis using pollen mother cells also revealed that it is not the major component of meiotic chromosomes, it seems to diffuse out once meiotic chromosomal condensation is completed. Synchronized tobacco BY-2 cell cultures were used to study the role of topoisomerase II in various stages of the cell cycle. Topoisomerase II transcript accumulation was observed during the S- and G2/M- phase of cell cycle. This biphasic expression pattern indicates the active requirement of topoisomerase II during these stages of the cell cycle. Through immuno-localization of topoisomerase II was observed diffusely throughout the nucleoplasm in interphase nuclei, whereas, the nucleolus region exhibited a more prominent immuno-positive staining that correlated with rRNA transcription, as shown by propidium iodide staining and BrUTP incorporation. The immuno-staining analysis also showed that topoisomerase II is the major component of mitotic chromosomes and remain attached to the chromosomes during cell division. The inhibition of topoisomerase II activity using specific inhibitors revealed quite dramatic effect on condensation of chromatin and chromosome individualization from prophase to metaphase transition. Partially condensed chromosomes were not arranged on metaphase plate and chromosomal perturbations were observed when advance to anaphase, suggesting the importance of topoisomerase II activity for proper chromosome condensation and segregation during mitosis. Contrary, topoisomerase II is not the major component of meiotic chromosomes, even though mitosis and meiosis share many processes, including the DNA replication, chromosome condensation and precisely regulated partitioning of chromosomes into daughter cells. Even if topoisomerase II is
Kovalev, Vadim M.; Tse, Wang-Kong
2017-11-01
We develop a microscopic theory for the relaxation dynamics of an optically pumped two-level system (TLS) coupled to a bath of weakly interacting Bose gas. Using Keldysh formalism and diagrammatic perturbation theory, expressions for the relaxation times of the TLS Rabi oscillations are derived when the boson bath is in the normal state and the Bose–Einstein condensate (BEC) state. We apply our general theory to consider an irradiated quantum dot coupled with a boson bath consisting of a two-dimensional dipolar exciton gas. When the bath is in the BEC regime, relaxation of the Rabi oscillations is due to both condensate and non-condensate fractions of the bath bosons for weak TLS-light coupling and pre dominantly due to the non-condensate fraction for strong TLS-light coupling. Our theory also shows that a phase transition of the bath from the normal to the BEC state strongly influences the relaxation rate of the TLS Rabi oscillations. The TLS relaxation rate is approximately independent of the pump field frequency and monotonically dependent on the field strength when the bath is in the low-temperature regime of the normal phase. Phase transition of the dipolar exciton gas leads to a non-monotonic dependence of the TLS relaxation rate on both the pump field frequency and field strength, providing a characteristic signature for the detection of BEC phase transition of the coupled dipolar exciton gas.
Wen, Lin; Zhang, Xiao-Fei; Hu, Ai-Yuan; Zhou, Jing; Yu, Peng; Xia, Lei; Sun, Qing; Ji, An-Chun
2018-03-01
We investigate the dynamics of bright-bright solitons in one-dimensional two-component Bose-Einstein condensates with Raman-induced spin-orbit coupling, via the variational approximation and the numerical simulation of Gross-Pitaevskii equations. For the uniform system without trapping potential, we obtain two population balanced stationary solitons. By performing the linear stability analysis, we find a Goldstone eigenmode and an oscillation eigenmode around these stationary solitons. Moreover, we derive a general dynamical solution to describe the center-of-mass motion and spin evolution of the solitons under the action of spin-orbit coupling. The effects of a harmonic trap have also been discussed.
Some concepts in condensed phase chemical kinetics
International Nuclear Information System (INIS)
Adelman, S.A.
1986-01-01
Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms
Misra, Prasanta K
2012-01-01
Physics of Condensed Matter is designed for a two-semester graduate course on condensed matter physics for students in physics and materials science. While the book offers fundamental ideas and topic areas of condensed matter physics, it also includes many recent topics of interest on which graduate students may choose to do further research. The text can also be used as a one-semester course for advanced undergraduate majors in physics, materials science, solid state chemistry, and electrical engineering, because it offers a breadth of topics applicable to these majors. The book be
Path-integral isomorphic Hamiltonian for including nuclear quantum effects in non-adiabatic dynamics
Tao, Xuecheng; Shushkov, Philip; Miller, Thomas F.
2018-03-01
We describe a path-integral approach for including nuclear quantum effects in non-adiabatic chemical dynamics simulations. For a general physical system with multiple electronic energy levels, a corresponding isomorphic Hamiltonian is introduced such that Boltzmann sampling of the isomorphic Hamiltonian with classical nuclear degrees of freedom yields the exact quantum Boltzmann distribution for the original physical system. In the limit of a single electronic energy level, the isomorphic Hamiltonian reduces to the familiar cases of either ring polymer molecular dynamics (RPMD) or centroid molecular dynamics Hamiltonians, depending on the implementation. An advantage of the isomorphic Hamiltonian is that it can easily be combined with existing mixed quantum-classical dynamics methods, such as surface hopping or Ehrenfest dynamics, to enable the simulation of electronically non-adiabatic processes with nuclear quantum effects. We present numerical applications of the isomorphic Hamiltonian to model two- and three-level systems, with encouraging results that include improvement upon a previously reported combination of RPMD with surface hopping in the deep-tunneling regime.
Confinement contains condensates
DEFF Research Database (Denmark)
Brodsky, S. J.; Roberts, C. D.; Shrock, R.
2012-01-01
Dynamical chiral symmetry breaking and its connection to the generation of hadron masses has historically been viewed as a vacuum phenomenon. We argue that confinement makes such a position untenable. If quark-hadron duality is a reality in QCD, then condensates, those quantities that have common...... evidence and incidentally expose misconceptions in a recent Comment....
Condenser assembly system for an appliance
Energy Technology Data Exchange (ETDEWEB)
Litch, Andrew David
2017-10-17
An appliance includes a compact condenser assembly formed with at least two separately and independently produced wire on tube condensers. Each of the at least two wire on tube condensers has a condenser inlet and a condenser outlet. The at least two wire on tube condensers are at least substantially locked and positioned in a matingly engaged configuration forming a compact condenser assembly. The at least two wire on tube condensers are configured to be operationally connected in at least one of a parallel configuration, a series configuration, a selectable configuration, and a bypass configuration.
Including Memory Friction in Single- and Two-State Quantum Dynamics Simulations.
Brown, Paul A; Messina, Michael
2016-03-03
We present a simple computational algorithm that allows for the inclusion of memory friction in a quantum dynamics simulation of a small, quantum, primary system coupled to many atoms in the surroundings. We show how including a memory friction operator, F̂, in the primary quantum system's Hamiltonian operator builds memory friction into the dynamics of the primary quantum system. We show that, in the harmonic, semi-classical limit, this friction operator causes the classical phase-space centers of a wavepacket to evolve exactly as if it were a classical particle experiencing memory friction. We also show that this friction operator can be used to include memory friction in the quantum dynamics of an anharmonic primary system. We then generalize the algorithm so that it can be used to treat a primary quantum system that is evolving, non-adiabatically on two coupled potential energy surfaces, i.e., a model that can be used to model H atom transfer, for example. We demonstrate this approach's computational ease and flexibility by showing numerical results for both harmonic and anharmonic primary quantum systems in the single surface case. Finally, we present numerical results for a model of non-adiabatic H atom transfer between a reactant and product state that includes memory friction on one or both of the non-adiabatic potential energy surfaces and uncover some interesting dynamical effects of non-memory friction on the H atom transfer process.
Zhang, Zhao-Hui; Mu, Shu-Mei; Guo, Ming-Shen; Wu, Jiang-Li; Li, Yan-Qin; Zhang, Han; Wang, Ying; Kang, Xian-Jiang
2016-04-28
Histones and histone phosphorylation play vital roles during animal spermatogenesis and spermatozoa maturation. The dynamic distribution of histones H2A and H4 and phosphorylated H2A and H4 at serine 1 (HS1ph) was explored in mammalian and Decapoda germ cells, with a special focus on the distribution of H2A, H4 and HS1ph between mouse condensed spermatozoa chromatin and crab non-condensed spermatozoa chromatin. The distribution of histone marks was also analysed in mature spermatozoa with different chromatin structures. Histone H2A and H4 marks were closely associated with the relatively loose chromatin structure in crab spermatozoa. The significant decrease in the HS1ph signal during spermatogenesis suggests that eliminating most of these epigenetic marks in the nucleusis closely associated with spermatozoa maturity.
Solano, Carlos J F; Pothula, Karunakar R; Prajapati, Jigneshkumar D; De Biase, Pablo M; Noskov, Sergei Yu; Kleinekathöfer, Ulrich
2016-05-10
All-atom molecular dynamics simulations have a long history of applications studying ion and substrate permeation across biological and artificial pores. While offering unprecedented insights into the underpinning transport processes, MD simulations are limited in time-scales and ability to simulate physiological membrane potentials or asymmetric salt solutions and require substantial computational power. While several approaches to circumvent all of these limitations were developed, Brownian dynamics simulations remain an attractive option to the field. The main limitation, however, is an apparent lack of protein flexibility important for the accurate description of permeation events. In the present contribution, we report an extension of the Brownian dynamics scheme which includes conformational dynamics. To achieve this goal, the dynamics of amino-acid residues was incorporated into the many-body potential of mean force and into the Langevin equations of motion. The developed software solution, called BROMOCEA, was applied to ion transport through OmpC as a test case. Compared to fully atomistic simulations, the results show a clear improvement in the ratio of permeating anions and cations. The present tests strongly indicate that pore flexibility can enhance permeation properties which will become even more important in future applications to substrate translocation.
Ishiyama, Tatsuya; Yano, Takeru; Fujikawa, Shigeo
2004-01-01
The kinetic boundary condition for the Boltzmann equation at an interface between a polyatomic vapor and its liquid phase is investigated by the numerical method of molecular dynamics, with particular emphasis on the functional form of the evaporation part of the boundary condition, including the evaporation coefficient. The present study is an extension of a previous one for argon [Ishiyama, Yano, and Fujikawa, Phys. Fluids 16, 2899 (2004)] to water and methanol, typical examples of polyatom...
Hasan, Mohammad Nasim; Rabbi, Kazi Fazle; Sabah, Arefiny; Ahmed, Jannat; Kuri, Subrata Kumar; Rakibuzzaman, S. M.
2017-06-01
Investigation of Molecular level phase change phenomena are becoming important in heat and mass transfer research at a very high rate, driven both by the need to understand certain fundamental phenomena as well as by a plethora of new and forthcoming applications in the areas of micro- and nanotechnologies. Molecular dynamics simulation has been carried out to go through the evaporation and condensation characteristics of thin liquid argon film in Nano-scale confinement. In the present study, a cuboid system is modeled for understanding the Nano-scale physics of simultaneous evaporation and condensation. The cuboid system consists of hot and cold parallel platinum plates at the bottom and top ends. The fluid comprised of liquid argon film at the bottom plate and vapor argon in between liquid argon and upper plate of the domain. Three different simulation domains have been created here: (i) Both platinum plates are considered flat, (ii) Upper plate consisting of transverse slots of low height and (iii) Upper plate consisting of transverse slots of bigger height. Considering hydrophilic nature of top and bottom plates, two different high temperatures of the hot wall was set and an observation was made on normal and explosive vaporizations and their impacts on thermal transport. For all the structures, equilibrium molecular dynamics (EMD) was performed to reach equilibrium state at 90 K. Then the lower wall is set to two different temperatures like 110 K and 250 K for all three models to perform non-equilibrium molecular dynamics (NEMD). For vaporization, higher temperature of the hot wall led to faster transport of the liquid argon as a cluster moving from hot wall to cold wall. But excessive temperature causes explosive boiling which seems not good for heat transportation because of less phase change. In case of condensation, an observation was made which indicates that the nanostructured transverse slots facilitate condensation. Two factors affect the rate of
Condensate of massive graviton and dark matter
Aoki, Katsuki; Maeda, Kei-ichi
2018-02-01
We study coherently oscillating massive gravitons in the ghost-free bigravity theory. This coherent field can be interpreted as a condensate of the massive gravitons. We first define the effective energy-momentum tensor of the coherent massive gravitons in a curved spacetime. We then study the background dynamics of the Universe and the cosmic structure formation including the effects of the coherent massive gravitons. We find that the condensate of the massive graviton behaves as a dark matter component of the Universe. From the geometrical point of view the condensate is regarded as a spacetime anisotropy. Hence, in our scenario, dark matter is originated from the tiny deformation of the spacetime. We also discuss a production of the spacetime anisotropy and find that the extragalactic magnetic field of a primordial origin can yield a sufficient amount for dark matter.
The NSF Condensed Matter Physics Program
Sokol, Paul
The Condensed Matter Physics (CMP) program in the NSF Division of Materials Research (DMR) supports experimental, as well as combined experiment and theory projects investigating the fundamental physics behind phenomena exhibited by condensed matter systems. CMP is the largest Individual Investigator Award program in DMR and supports a broad portfolio of research spanning both hard and soft condensed matter. Representative research areas include: 1) phenomena at the nano- to macro-scale including: transport, magnetic, and optical phenomena; classical and quantum phase transitions; localization; electronic, magnetic, and lattice structure or excitations; superconductivity; topological insulators; and nonlinear dynamics. 2) low-temperature physics: quantum fluids and solids; 1D & 2D electron systems. 3) soft condensed matter: partially ordered fluids, granular and colloid physics, liquid crystals, and 4) understanding the fundamental physics of new states of matter as well as the physical behavior of condensed matter under extreme conditions e.g., low temperatures, high pressures, and high magnetic fields. In this talk I will review the current CMP portfolio and discuss future funding trends for the program. I will also describe recent activities in the program aimed at addressing the challenges facing current and future principal investigators.
Kasamatsu, Kenichi; Eto, Minoru; Nitta, Muneto
2016-01-01
We study the interaction and dynamics of two half-quantized vortices in two-component Bose-Einstein condensates. Using the Padé approximation for the vortex core profile, we calculate the intervortex potential, whose asymptotic form for a large distance has been derived by Eto et al. [Phys. Rev. A 83, 063603 (2011), 10.1103/PhysRevA.83.063603]. Through numerical simulations of the two-dimensional Gross-Pitaevskii equations, we reveal different kinds of dynamical trajectories of the vortices depending on the combinations of signs of circulations and the intercomponent density coupling. Under the adiabatic limit, we derive the equations of motion for the vortex coordinates, in which the motion is caused by the balance between Magnus force and the intervortex forces. The initial velocity of the vortex motion can be explained quantitatively by this point vortex approximation, but understanding the long-time behavior of the dynamics needs more consideration beyond our model.
Hiragami-Hamada, Kyoko; Soeroes, Szabolcs; Nikolov, Miroslav; Wilkins, Bryan; Kreuz, Sarah; Chen, Carol; De La Rosa-Velázquez, Inti A.; Zenn, Hans Michael; Kost, Nils; Pohl, Wiebke; Chernev, Aleksandar; Schwarzer, Dirk; Jenuwein, Thomas; Lorincz, Matthew; Zimmermann, Bastian; Walla, Peter Jomo; Neumann, Heinz; Baubec, Tuncay; Urlaub, Henning; Fischle, Wolfgang
2016-01-01
Histone H3 trimethylation of lysine 9 (H3K9me3) and proteins of the heterochromatin protein 1 (HP1) family are hallmarks of heterochromatin, a state of compacted DNA essential for genome stability and long-term transcriptional silencing. The mechanisms by which H3K9me3 and HP1 contribute to chromatin condensation have been speculative and controversial. Here we demonstrate that human HP1β is a prototypic HP1 protein exemplifying most basal chromatin binding and effects. These are caused by dimeric and dynamic interaction with highly enriched H3K9me3 and are modulated by various electrostatic interfaces. HP1β bridges condensed chromatin, which we postulate stabilizes the compacted state. In agreement, HP1β genome-wide localization follows H3K9me3-enrichment and artificial bridging of chromatin fibres is sufficient for maintaining cellular heterochromatic conformation. Overall, our findings define a fundamental mechanism for chromatin higher order structural changes caused by HP1 proteins, which might contribute to the plastic nature of condensed chromatin. PMID:27090491
Richter, Martin; Marquetand, Philipp; González-Vázquez, Jesús; Sola, Ignacio; González, Leticia
2011-05-10
We present a semiclassical surface-hopping method which is able to treat arbitrary couplings in molecular systems including all degrees of freedom. A reformulation of the standard surface-hopping scheme in terms of a unitary transformation matrix allows for the description of interactions like spin-orbit coupling or transitions induced by laser fields. The accuracy of our method is demonstrated in two systems. The first one, consisting of two model electronic states, validates the semiclassical approach in the presence of an electric field. In the second one, the dynamics in the IBr molecule in the presence of spin-orbit coupling after laser excitation is investigated. Due to an avoided crossing that originates from spin-orbit coupling, IBr dissociates into two channels: I + Br((2)P3/2) and I + Br*((2)P1/2). In both systems, the obtained results are in very good agreement with those calculated from exact quantum dynamical simulations.
Directory of Open Access Journals (Sweden)
2008-12-01
Full Text Available Atropisomeric biaryl aldehydes undergo diastereoselective condensation with (−-ephedrine and with a proline-derived diamine, with selectivity highly dependent on solvent, temperature and reaction conditions. Levels of thermodynamic control up to 5:1 may be obtained by heating the diamine with the aldehyde in a sealed tube. Alternatively, crystallisation-induced dynamic transformation allows isolation of a single diastereoisomer in up to 85% yield. Hydrolysis and reduction of the major diastereoisomeric product of the reaction yields atropisomeric biaryls in >99:1 enantiomeric ratios.
Izmailov, I. A.; Naumov, V. V.; Kochelap, V. A.
2013-11-01
The kinetics of the superluminescence of lead atoms, Pb 3 P {1/0} → 1 D 2 (722.9 nm) and 3 P {1/0} → 3 P 2 (405.8 nm), at the fast adiabatic expansion and cooling of the detonation products of lead azide Pb(N3)2 in vacuum has been studied. The effects of the condensation and scattering of light from drop clusters in an optically active heterophase medium has been analyzed in order to interpret the experiments in laser detonation plasma-dynamic systems based on metal azides.
International Nuclear Information System (INIS)
Beretta, M.; Pilon, R.; Mut, F.
2002-01-01
Aim: To develop a procedure for the creation of nuclear medicine reports containing static and dynamic images. The reason for implementing this technique is the lack of adequate solutions for an electronic format of nuclear medicine results allowing for rapid transmission via e-mail, specially in the case of dynamic and gated SPECT studies, since functional data is best presented in dynamic mode. Material and Methods: Clinical images were acquired in static, whole body, dynamic and gated mode, corresponding to bone studies, diuretic renogram, radionuclide cystography and gated perfusion SPECT, as well as respective time-activity curves. Image files were imported from a dedicated nuclear medicine computer system (Elscint XPert) to a Windows-based PC through a standard ethernet network with TCP-IP communications protocol, using a software developed by us which permits the conversion from the manufacturer's original format into a bitmap format (.bmp) compatible with commercially available PC software. For cardiac perfusion studies, background was subtracted prior to transferring to reduce the amount of information in the file; this was not done for other type of studies because useful data could be eliminated. Dynamic images were then processed using commercial software to create animated files and stored in .gif format. Static images were re-sized and stored in .jpg format. Original color or gray scale was always preserved. All the graphic material was then merged with a previously prepared report text using HTML format. The report also contained reference diagrams to facilitate interpretation. The whole report was then compressed into a self-extractable file, ready to be sent by electronic mail. Reception of the material was visually checked for data integrity including image quality by two experienced nuclear medicine physicians. Results: The report presented allows for simultaneous visualization of the text, diagrams and images either static, dynamic, gated or
Butler, Jason E.; Shaqfeh, Eric S. G.
2005-01-01
Using methods adapted from the simulation of suspension dynamics, we have developed a Brownian dynamics algorithm with multibody hydrodynamic interactions for simulating the dynamics of polymer molecules. The polymer molecule is modeled as a chain composed of a series of inextensible, rigid rods with constraints at each joint to ensure continuity of the chain. The linear and rotational velocities of each segment of the polymer chain are described by the slender-body theory of Batchelor [J. Fluid Mech. 44, 419 (1970)]. To include hydrodynamic interactions between the segments of the chain, the line distribution of forces on each segment is approximated by making a Legendre polynomial expansion of the disturbance velocity on the segment, where the first two terms of the expansion are retained in the calculation. Thus, the resulting linear force distribution is specified by a center of mass force, couple, and stresslet on each segment. This method for calculating the hydrodynamic interactions has been successfully used to simulate the dynamics of noncolloidal suspensions of rigid fibers [O. G. Harlen, R. R. Sundararajakumar, and D. L. Koch, J. Fluid Mech. 388, 355 (1999); J. E. Butler and E. S. G. Shaqfeh, J. Fluid Mech. 468, 204 (2002)]. The longest relaxation time and center of mass diffusivity are among the quantities calculated with the simulation technique. Comparisons are made for different levels of approximation of the hydrodynamic interactions, including multibody interactions, two-body interactions, and the "freely draining" case with no interactions. For the short polymer chains studied in this paper, the results indicate a difference in the apparent scaling of diffusivity with polymer length for the multibody versus two-body level of approximation for the hydrodynamic interactions.
Transient Response Dynamic Module Modifications to Include Static and Kinetic Friction Effects
Misel, J. E.; Nenno, S. B.; Takahashi, D.
1984-01-01
A methodology that supports forced transient response dynamic solutions when both static and kinetic friction effects are included in a structural system model is described. Modifications that support this type of nonlinear transient response solution are summarized for the transient response dynamics (TRD) NASTRAN module. An overview of specific modifications for the NASTRAN processing subroutines, INITL, TRD1C, and TRD1D, are described with further details regarding inspection of nonlinear input definitions to define the type of nonlinear solution required, along with additional initialization requirements and specific calculation subroutines to successfully solve the transient response problem. The extension of the basic NASTRAN nonlinear methodology is presented through several stages of development to the point where constraint equations and residual flexibility effects are introduced into the finite difference Newmark-Beta recurrsion formulas. Particular emphasis is placed on cost effective solutions for large finite element models such as the Space Shuttle with friction degrees of freedom between the orbiter and payloads mounted in the cargo bay. An alteration to the dynamic finite difference equations of motion is discussed, which allows one to include friction effects at reasonable cost for large structural systems such as the Space Shuttle. Data are presented to indicate the possible impact of transient friction loads to the payload designer for the Space Shuttle. Transient response solution data are also included, which compare solutions without friction forces and those with friction forces for payloads mounted in the Space Shuttle cargo bay. These data indicate that payload components can be sensitive to friction induced loads.
Homogeneous cosmologies as group field theory condensates
Energy Technology Data Exchange (ETDEWEB)
Gielen, Steffen [Perimeter Institute for Theoretical Physics,31 Caroline St. N., Waterloo, Ontario N2L 2Y5 (Canada); Oriti, Daniele; Sindoni, Lorenzo [Max Planck Institute for Gravitational Physics (Albert Einstein Institute),Am Mühlenberg 1, 14476 Golm (Germany)
2014-06-03
We give a general procedure, in the group field theory (GFT) formalism for quantum gravity, for constructing states that describe macroscopic, spatially homogeneous universes. These states are close to coherent (condensate) states used in the description of Bose-Einstein condensates. The condition on such states to be (approximate) solutions to the quantum equations of motion of GFT is used to extract an effective dynamics for homogeneous cosmologies directly from the underlying quantum theory. The resulting description in general gives nonlinear and nonlocal equations for the ‘condensate wavefunction’ which are analogous to the Gross-Pitaevskii equation in Bose-Einstein condensates. We show the general form of the effective equations for current quantum gravity models, as well as some concrete examples. We identify conditions under which the dynamics becomes linear, admitting an interpretation as a quantum-cosmological Wheeler-DeWitt equation, and give its semiclassical (WKB) approximation in the case of a kinetic term that includes a Laplace-Beltrami operator. For isotropic states, this approximation reproduces the classical Friedmann equation in vacuum with positive spatial curvature. We show how the formalism can be consistently extended from Riemannian signature to Lorentzian signature models, and discuss the addition of matter fields, obtaining the correct coupling of a massless scalar in the Friedmann equation from the most natural extension of the GFT action. We also outline the procedure for extending our condensate states to include cosmological perturbations. Our results form the basis of a general programme for extracting effective cosmological dynamics directly from a microscopic non-perturbative theory of quantum gravity.
International Nuclear Information System (INIS)
Hamazaki, Ryoichi.
1992-01-01
The condensator of the present invention has a condensate return pipe for returning condensates formed by concentration of steams in a bundle of heat transfer tubes. A flow rate control valve is disposed to the return pipe, and the opening degree of the control valve is controlled by a valve opening degree control device which receives a reactor pressure signal under control. The valve opening degree control device outputs a control signal of 0% valve opening degree when reactor pressure is lower than the lowermost control value and outputs control signal of 100% value opening degree if it is greater than the uppermost control value. On the other hand, when it is between the lowermost value and the uppermost value, it outputs a control signal for demanding an opening degree in proportion to the difference between the reactor pressure and the lowermost control value. Since it is thus controlled, even if steams and condensaes are circulated as they are by natural convection, there is no worry that reactor pressure lowers excessively and no operator's manual handling is necessary. (T.M.)
Conceptualizing a Dynamic Fall Risk Model Including Intrinsic Risks and Exposures.
Klenk, Jochen; Becker, Clemens; Palumbo, Pierpaolo; Schwickert, Lars; Rapp, Kilan; Helbostad, Jorunn L; Todd, Chris; Lord, Stephen R; Kerse, Ngaire
2017-11-01
Falls are a major cause of injury and disability in older people, leading to serious health and social consequences including fractures, poor quality of life, loss of independence, and institutionalization. To design and provide adequate prevention measures, accurate understanding and identification of person's individual fall risk is important. However, to date, the performance of fall risk models is weak compared with models estimating, for example, cardiovascular risk. This deficiency may result from 2 factors. First, current models consider risk factors to be stable for each person and not change over time, an assumption that does not reflect real-life experience. Second, current models do not consider the interplay of individual exposure including type of activity (eg, walking, undertaking transfers) and environmental risks (eg, lighting, floor conditions) in which activity is performed. Therefore, we posit a dynamic fall risk model consisting of intrinsic risk factors that vary over time and exposure (activity in context). eHealth sensor technology (eg, smartphones) begins to enable the continuous measurement of both the above factors. We illustrate our model with examples of real-world falls from the FARSEEING database. This dynamic framework for fall risk adds important aspects that may improve understanding of fall mechanisms, fall risk models, and the development of fall prevention interventions. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Sakmann, Kaspar
2010-07-21
In this thesis, the physics of trapped, interacting Bose-Einstein condensates is analyzed by solving the many-body Schroedinger equation. Particular emphasis is put on coherence, fragmentation and reduced density matrices. First, the ground state of a trapped Bose-Einstein condensate and its correlation functions are obtained. Then the dynamics of a bosonic Josephson junction is investigated by solving the time-dependent many-body Schroedinger equation numerically exactly. These are the first exact results in literature in this context. It is shown that the standard approximations of the field, Gross-Pitaevskii theory and the Bose-Hubbard model fail at weak interaction strength and within their range of expected validity. For stronger interactions the dynamics becomes strongly correlated and a new equilibration phenomenon is discovered. By comparison with exact results it is shown that a symmetry of the Bose- Hubbard model between attractive and repulsive interactions must be considered an artefact of the model. A conceptual innovation of this thesis are time-dependent Wannier functions. Equations of motion for time-dependent Wannier functions are derived from the variational principle. By comparison with exact results it is shown that lattice models can be greatly improved at little computational cost by letting the Wannier functions of a lattice model become time-dependent. (orig.)
International Nuclear Information System (INIS)
Liang, Z.X.; Zhang, Z.D.; Liu, W.M.
2005-01-01
We present a family of exact solutions of the one-dimensional nonlinear Schroedinger equation which describes the dynamics of a bright soliton in Bose-Einstein condensates with the time-dependent interatomic interaction in an expulsive parabolic potential. Our results show that, under a safe range of parameters, the bright soliton can be compressed into very high local matter densities by increasing the absolute value of the atomic scattering length, which can provide an experimental tool for investigating the range of validity of the one-dimensional Gross-Pitaevskii equation. We also find that the number of atoms in the bright soliton keeps dynamic stability: a time-periodic atomic exchange is formed between the bright soliton and the background
Marder, Michael P
2010-01-01
This Second Edition presents an updated review of the whole field of condensed matter physics. It consolidates new and classic topics from disparate sources, teaching not only about the effective masses of electrons in semiconductor crystals and band theory, but also about quasicrystals, dynamics of phase separation, why rubber is more floppy than steel, granular materials, quantum dots, Berry phases, the quantum Hall effect, and Luttinger liquids.
Energy Technology Data Exchange (ETDEWEB)
Bruno, A.; Sarica, C.; Chen, H.; Volk, M. [Tulsa Univ., OK (United States)
2008-07-01
This study examined the paraffin deposition for dispersed flows of oil and water and proposed a flow assurance tool for the analysis of production systems. First, paraffin deposition was investigated under two-phase oil-water flow conditions to determine the effect that water concentration has on the deposition process. A newly modified model was then proposed to better predict paraffin deposition compared to currently available models. Two different crude oils with very different physical properties, notably South Pelto Crude Oil and Garden Banks Condensate, were studied in a small-scale flow loop at the Tulsa University Paraffin Deposition Project. A total of 8 oil-water deposition tests, 2 single-phase deposition tests, and 2 inversion point tests were conducted. Four different water cuts were selected for each fluid. The deposit thickness showed a decreasing trend with increasing water cuts for both the South Pelto oil and Garden Banks condensate tests. There was no deposit in South Pelto's water, but the Garden Banks condensate test with 85 per cent water cut generated a very thin and hard deposit film, indicating that there must be a different deposition mechanism other than the ones based on conventional diffusion theory. A reduction in Reynolds number also resulted in a lower paraffin content of the deposits. The volume fraction of water in the deposit was lower than the initial water cut of the mixture for both fluids. Garden Banks had less water fraction in the deposit compared to South Pelto. The preliminary oil-water paraffin deposition model developed by Couto was validated against experimental data. Several modifications were proposed in order to consider water concentration in the deposit and changes in the diffusion coefficient for water dominated flows. Model predictions were in fairly good agreement with experimental results. 1 ref.
Statistical physics and condensed matter
International Nuclear Information System (INIS)
2003-01-01
This document is divided into 4 sections: 1) General aspects of statistical physics. The themes include: possible geometrical structures of thermodynamics, the thermodynamical foundation of quantum measurement, transport phenomena (kinetic theory, hydrodynamics and turbulence) and out of equilibrium systems (stochastic dynamics and turbulence). The techniques involved here are typical of applied analysis: stability criteria, mode decomposition, shocks and stochastic equations. 2) Disordered, glassy and granular systems: statics and dynamics. The complexity of the systems can be studied through the structure of their phase space. The geometry of this phase space is studied in several works: the overlap distribution can now be computed with a very high precision; the boundary energy between low lying states does not behave like in ordinary systems; and the Edward's hypothesis of equi-probability of low lying metastable states is invalidated. The phenomenon of aging, characteristic of glassy dynamics, is studied in several models. Dynamics of biological systems or of fracture is shown to bear some resemblance with that of disordered systems. 3) Quantum systems. The themes include: mesoscopic superconductors, supersymmetric approach to strongly correlated electrons, quantum criticality and heavy fermion compounds, optical sum rule violation in the cuprates, heat capacity of lattice spin models from high-temperature series expansion, Lieb-Schultz-Mattis theorem in dimension larger than one, quantum Hall effect, Bose-Einstein condensation and multiple-spin exchange model on the triangular lattice. 4) Soft condensed matter and biological systems. Path integral representations are invaluable to describe polymers, proteins and self-avoiding membranes. Using these methods, problems as diverse as the titration of a weak poly-acid by a strong base, the denaturation transition of DNA or bridge-hopping in conducting polymers have been addressed. The problems of RNA folding has
Hamiltonian and Lagrangian dynamics of charged particles including the effects of radiation damping
Qin, Hong; Burby, Joshua; Davidson, Ronald; Fisch, Nathaniel; Chung, Moses
2015-11-01
The effects of radiation damping (radiation reaction) on accelerating charged particles in modern high-intensity accelerators and high-intensity laser beams have becoming increasingly important. Especially for electron accelerators and storage rings, radiation damping is an effective mechanism and technique to achieve high beam luminosity. We develop Hamiltonian and Lagrangian descriptions of the classical dynamics of a charged particle including the effects of radiation damping in the general electromagnetic focusing channels encountered in accelerators. The direct connection between the classical Hamiltonian and Lagrangian theories and the more fundamental QED description of the synchrotron radiation process is also addressed. In addition to their theoretical importance, the classical Hamiltonian and Lagrangian theories of the radiation damping also enable us to numerically integrate the dynamics using advanced structure-preserving geometric algorithms. These theoretical developments can also be applied to runaway electrons and positrons generated during the disruption or startup of tokamak discharges. This research was supported by the U.S. Department of Energy (DE-AC02-09CH11466).
On the Necessity of Including Joint Passive Dynamics in the Impedance Control of Robotic Legs
Directory of Open Access Journals (Sweden)
Juan Carlos Arevalo
2014-07-01
Full Text Available Bioinspired quadruped robots are among the best robot designs for field missions over the complex terrain encountered in extraterrestrial landscapes and disaster scenarios caused by natural and human-made catastrophes, such as those caused by nuclear power plant accidents and radiological emergencies. For such applications, the performance characteristics of the robots should include high mobility, adaptability to the terrain, the ability to handle a large payload and good endurance. Nature can provide inspiration for quadruped designs that are well suited for traversing complex terrain. Horse legs are an example of a structure that has evolved to exhibit good performance characteristics. In this paper, a leg design exhibiting the key features of horse legs is briefly described. This leg is an underactuated mechanism because it has two actively driven degrees of freedom (DOFs and one passively driven DOF. In this work, two control laws intended to be use in the stan ce phase are described: a control law that considers passive mechanism dynamics and a second law that neglects these dynamics. The performance of the two control laws is experimentally evaluated and compared. The results indicate that the first control law better achieves the control goal; however, the use of the second is not completely unjustified.
Wai, Rong-Jong; Muthusamy, Rajkumar
2013-02-01
This paper presents the design and analysis of an intelligent control system that inherits the robust properties of sliding-mode control (SMC) for an n-link robot manipulator, including actuator dynamics in order to achieve a high-precision position tracking with a firm robustness. First, the coupled higher order dynamic model of an n-link robot manipulator is briefy introduced. Then, a conventional SMC scheme is developed for the joint position tracking of robot manipulators. Moreover, a fuzzy-neural-network inherited SMC (FNNISMC) scheme is proposed to relax the requirement of detailed system information and deal with chattering control efforts in the SMC system. In the FNNISMC strategy, the FNN framework is designed to mimic the SMC law, and adaptive tuning algorithms for network parameters are derived in the sense of projection algorithm and Lyapunov stability theorem to ensure the network convergence as well as stable control performance. Numerical simulations and experimental results of a two-link robot manipulator actuated by DC servo motors are provided to justify the claims of the proposed FNNISMC system, and the superiority of the proposed FNNISMC scheme is also evaluated by quantitative comparison with previous intelligent control schemes.
Statistical physics including applications to condensed matter
Hermann, Claudine
2005-01-01
Statistical Physics bridges the properties of a macroscopic system and the microscopic behavior of its constituting particles, otherwise impossible due to the giant magnitude of Avogadro's number. Numerous systems of today's key technologies -- as e.g. semiconductors or lasers -- are macroscopic quantum objects; only statistical physics allows for understanding their fundamentals. Therefore, this graduate text also focuses on particular applications such as the properties of electrons in solids with applications, and radiation thermodynamics and the greenhouse effect.
Multi-Objective Dynamic Economic Dispatch of Microgrid Systems Including Vehicle-to-Grid
Directory of Open Access Journals (Sweden)
Haitao Liu
2015-05-01
Full Text Available Based on the characteristics of electric vehicles (EVs, this paper establishes the load models of EVs under the autonomous charging mode and the coordinated charging and discharging mode. Integrating the EVs into a microgrid system which includes wind turbines (WTs, photovoltaic arrays (PVs, diesel engines (DEs, fuel cells (FCs and a storage battery (BS, this paper establishes multi-objective economic dispatch models of a microgrid, including the lowest operating cost, the least carbon dioxide emissions, and the lowest pollutant treatment cost. After converting the multi-objective functions to a single objective function by using the judgment matrix method, we analyze the dynamic economic dispatch of the microgrid system including vehicle-to-grid (V2G with an improved particle swarm optimization algorithm under different operation control strategies. With the example system, the proposed models and strategies are verified and analyzed. Simulation results show that the microgrid system with EVs under the coordinated charging and discharging mode has better operation economics than the autonomous charging mode. Meanwhile, the greater the load fluctuation is, the higher the operating cost of the microgrid system is.
Isihara, A
2007-01-01
More than a graduate text and advanced research guide on condensed matter physics, this volume is useful to plasma physicists and polymer chemists, and their students. It emphasizes applications of statistical mechanics to a variety of systems in condensed matter physics rather than theoretical derivations of the principles of statistical mechanics and techniques. Isihara addresses a dozen different subjects in separate chapters, each designed to be directly accessible and used independently of previous chapters. Topics include simple liquids, electron systems and correlations, two-dimensional
Excitations of Bose-Einstein condensates at finite temperatures
International Nuclear Information System (INIS)
Rusch, M.
2000-01-01
Recent experimental observations of collective excitations of Bose condensed atomic vapours have stimulated interest in the microscopic description of the dynamics of a Bose-Einstein condensate confined in an external potential. We present a finite temperature field theory for collective excitations of trapped Bose-Einstein condensates and use a finite-temperature linear response formalism, which goes beyond the simple mean-field approximation of the Gross-Pitaevskii equation. The effect of the non-condensed thermal atoms we include using perturbation theory in a quasiparticle basis. This presents a simple scheme to understand the interaction between condensate and non-condensed atoms and enables us to include the effect the condensate has on collision dynamics. At first we limit our treatment to the case of a spatially homogeneous Bose gas. We include the effect of pair and triplet anomalous averages and thus obtain a gapless theory for the excitations of a weakly interacting system, which we can link to well known results for Landau and Beliaev damping rates. A gapless theory for trapped systems with a static thermal component follows straightforwardly. We then investigate finite temperature excitations of a condensate in a spherically symmetric harmonic trap. We avoid approximations to the density of states and thus emphasise finite size aspects of the problem. We show that excitations couple strongly to a restricted number of modes, giving rise to resonance structure in their frequency spectra. Where possible we derive energy shifts and lifetimes of excitations. For one particular mode, the breathing mode, the effects of the discreteness of the system are sufficiently pronounced that the simple picture of an energy shift and width fails. Experiments in spherical traps have recently become feasible and should be able to test our detailed quantitative predictions. (author)
Bose-Einstein Condensation in Complex Networks
Energy Technology Data Exchange (ETDEWEB)
Bianconi, Ginestra; Barabasi, Albert-Laszlo
2001-06-11
The evolution of many complex systems, including the World Wide Web, business, and citation networks, is encoded in the dynamic web describing the interactions between the system's constituents. Despite their irreversible and nonequilibrium nature these networks follow Bose statistics and can undergo Bose-Einstein condensation. Addressing the dynamical properties of these nonequilibrium systems within the framework of equilibrium quantum gases predicts that the {open_quotes}first-mover-advantage,{close_quotes} {open_quotes}fit-get-rich,{close_quotes} and {open_quotes}winner-takes-all{close_quotes} phenomena observed in competitive systems are thermodynamically distinct phases of the underlying evolving networks.
Bose-Einstein Condensation in Complex Networks
International Nuclear Information System (INIS)
Bianconi, Ginestra; Barabasi, Albert-Laszlo
2001-01-01
The evolution of many complex systems, including the World Wide Web, business, and citation networks, is encoded in the dynamic web describing the interactions between the system's constituents. Despite their irreversible and nonequilibrium nature these networks follow Bose statistics and can undergo Bose-Einstein condensation. Addressing the dynamical properties of these nonequilibrium systems within the framework of equilibrium quantum gases predicts that the 'first-mover-advantage,' 'fit-get-rich,' and 'winner-takes-all' phenomena observed in competitive systems are thermodynamically distinct phases of the underlying evolving networks
Sumner, Isaiah; Iyengar, Srinivasan S
2007-10-18
We have introduced a computational methodology to study vibrational spectroscopy in clusters inclusive of critical nuclear quantum effects. This approach is based on the recently developed quantum wavepacket ab initio molecular dynamics method that combines quantum wavepacket dynamics with ab initio molecular dynamics. The computational efficiency of the dynamical procedure is drastically improved (by several orders of magnitude) through the utilization of wavelet-based techniques combined with the previously introduced time-dependent deterministic sampling procedure measure to achieve stable, picosecond length, quantum-classical dynamics of electrons and nuclei in clusters. The dynamical information is employed to construct a novel cumulative flux/velocity correlation function, where the wavepacket flux from the quantized particle is combined with classical nuclear velocities to obtain the vibrational density of states. The approach is demonstrated by computing the vibrational density of states of [Cl-H-Cl]-, inclusive of critical quantum nuclear effects, and our results are in good agreement with experiment. A general hierarchical procedure is also provided, based on electronic structure harmonic frequencies, classical ab initio molecular dynamics, computation of nuclear quantum-mechanical eigenstates, and employing quantum wavepacket ab initio dynamics to understand vibrational spectroscopy in hydrogen-bonded clusters that display large degrees of anharmonicities.
Quantum three-body reaction dynamics including the geometric phase effect
International Nuclear Information System (INIS)
Wu, Y.S.M.
1992-01-01
Accurate quantum mechanical reactive scattering calculations within the framework of symmetrized hyperspherical coordinate techniques are presented for several processes involving collisions of an electron with a hydrogen atom and an atom with a diatomic molecule in three-dimensional space, and the collinear collision of an atom with a diatomic molecule. In addition to the interest of the processes themselves, the results are compared with previous experimental and theoretical results in such a way as to provide tests of the general usefulness of the methods used. The general theory for the calculation of accurate differential cross sections in the reactive collision of an atom with a diatomic molecule including the geometric phase effect in three-dimensional space is described. This methodology has permitted, for the first time, the calculation of integral and differential cross sections over a significantly larger range of collision energies (up to 2.6 eV total energy) than previously possible for the system H + H 2 . The authors present numerical solutions of the quantum mechanical streamlines of probability current density for collinear atom-diatom reactions. It is used to study the barrier height dependence of dynamics on the Cl + HCl reaction
Energy Technology Data Exchange (ETDEWEB)
Noda, Yohei, E-mail: noda.yohei@jaea.go.jp [Quantum Beam Science Centre, Sector of Nuclear Science Research, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan); Kumada, Takayuki [Quantum Beam Science Centre, Sector of Nuclear Science Research, Kansai Photon Science Institute, Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Yamaguchi, Daisuke; Shamoto, Shin-ichi [Quantum Beam Science Centre, Sector of Nuclear Science Research, Japan Atomic Energy Agency, Shirakata-Shirane, Tokai, Ibaraki 319-1195 (Japan)
2015-03-11
We investigated the dynamic nuclear polarization (DNP) of typical thermosetting polymers (two-component type epoxy resins; Araldite{sup ®} Standard or Araldite{sup ®} Rapid) doped with a (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO) radical. The doping process was developed by carefully considering the decomposition of TEMPO during the solidification of the epoxy resin. The TEMPO electron spin in each two-component paste decayed slowly, which was favorable for our study. Furthermore, despite the dissolved TEMPO, the mixture of the two-component paste successfully solidified. With the resulting TEMPO-doped epoxy-resin samples, DNP experiments at 1.2 K and 3.35 T indicated a magnitude of a proton-spin polarization up to 39%. This polarization is similar to that (35%) obtained for TEMPO-doped polystyrene (PS), which is often used as a standard sample for DNP. To combine this solidification of TEMPO-including mixture with a resin-casting technique enables a creation of polymeric target materials with a precise and complex structure.
J. Rodnizki, D. Berkovits, K. Lavie, I. Mardor, A. Shor and Y. Yanay (Soreq NRC, Yavne), K. Dunkel, C. Piel (ACCEL, Bergisch Gladbach), A. Facco (INFN/LNL, Legnaro, Padova), V. Zviagintsev (TRIUMF, Vancouver)
AbstractBeam dynamics simulations of SARAF (Soreq Applied Research Accelerator Facility) superconducting RF linear accelerator have been performed in order to establish the accelerator design. The multi-particle simulation includes 3D realistic electromagnetic field distributions, space charge forces and fabrication, misalignment and operation errors. A 4 mA proton or deuteron beam is accelerated up to 40 MeV with a moderated rms emittance growth and a high real-estate gradient of 2 MeV/m. An envelope of 40,000 macro-particles is kept under a radius of 1.1 cm, well below the beam pipe bore radius. The accelerator design of SARAF is proposed as an injector for the EURISOL driver accelerator. The Accel 176 MHZ β0=0.09 and β0=0.15 HWR lattice was extended to 90 MeV based on the LNL 352 MHZ β0=0.31 HWR. The matching between both lattices ensures smooth transition and the possibility to extend the accelerator to the required EURISOL ion energy.
International Nuclear Information System (INIS)
Noda, Yohei; Kumada, Takayuki; Yamaguchi, Daisuke; Shamoto, Shin-ichi
2015-01-01
We investigated the dynamic nuclear polarization (DNP) of typical thermosetting polymers (two-component type epoxy resins; Araldite ® Standard or Araldite ® Rapid) doped with a (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO) radical. The doping process was developed by carefully considering the decomposition of TEMPO during the solidification of the epoxy resin. The TEMPO electron spin in each two-component paste decayed slowly, which was favorable for our study. Furthermore, despite the dissolved TEMPO, the mixture of the two-component paste successfully solidified. With the resulting TEMPO-doped epoxy-resin samples, DNP experiments at 1.2 K and 3.35 T indicated a magnitude of a proton-spin polarization up to 39%. This polarization is similar to that (35%) obtained for TEMPO-doped polystyrene (PS), which is often used as a standard sample for DNP. To combine this solidification of TEMPO-including mixture with a resin-casting technique enables a creation of polymeric target materials with a precise and complex structure
Condensation coefficient of water in a weak condensation state
International Nuclear Information System (INIS)
Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo
2008-01-01
The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].
Condensation coefficient of water in a weak condensation state
Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo
2008-07-01
The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].
Evaporation and condensation at a liquid methanol surface
Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke
1994-07-01
The dynamics of evaporation and condensation at a flat liquid surface of methanol were studied under the liquidvapor equilibrium condition at room temperature with molecular dynamics computer simulation techniques. Analysis of molecular trajectories shows that the condensation coefficient is 89%. It suggests that only a tenth of incident vapor molecules are reflected at the liquid surface, contrary to a prediction of a classical transition state theory. To investigate the potential barrier of the evaporation-condensation process, a particle insertion method was applied and the local chemical potential near the surface was evaluated. The calculated chemical potential is constant in the whole region including the surface layer and no potential barrier is observed in the vincinity of the surface, which casts strong doubt on the explanation of a transition state theory.
The importance of including dynamic soil-structure interaction into wind turbine simulation codes
DEFF Research Database (Denmark)
Damgaard, Mads; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo
2014-01-01
is examined. The optimal order of the models is determined and implemented into the aeroelastic code HAWC2, where the dynamic response of a 5.0 MW wind turbine is evaluated. In contrast to the fore-aft vibrations, the inclusion of soil-structure interaction is shown to be critical for the side-side vibrations......A rigorous numerical model, describing a wind turbine structure and subsoil, may contain thousands of degrees of freedom, making the approach computationally inefficient for fast time domain analysis. In order to meet the requirements of real-time calculations, the dynamic impedance...... of the wind turbine structure....
Situational effects of the school factors included in the dynamic model of educational effectiveness
Creerners, Bert; Kyriakides, Leonidas
We present results of a longitudinal study in which 50 schools, 113 classes and 2,542 Cypriot primary students participated. We tested the validity of the dynamic model of educational effectiveness and especially its assumption that the impact of school factors depends on the current situation of
Condensation of water vapor in the gravitational field
Energy Technology Data Exchange (ETDEWEB)
Gorshkov, V. G.; Makarieva, A. M.; Nefiodov, A. V., E-mail: anef@thd.pnpi.spb.ru [Konstantinov Petersburg Nuclear Physics Institute (Russian Federation)
2012-10-15
Physical peculiarities of water vapor condensation under conditions of hydrostatic equilibrium are considered. The power of stationary dynamic air fluxes and the vertical temperature distribution caused by condensation on large horizontal scales are estimated.
Theoretical Investigations of Trapped Interacting Bose-Einstein Condensates
National Research Council Canada - National Science Library
You, Li
1999-01-01
.... Primary topics being addressed are: (1) To understand the properties of atomic Bose-Einstein condensates, in particular, the low energy excitations, dynamics of Bose-Einstein condensation, vortex states creation and detection. (2...
The dynamics of tritium - including OBT- in the aquatic food chain
International Nuclear Information System (INIS)
Galeriu, D.; Heling, R.; Melintescu, A.
2005-01-01
Full text: Tritiated water spills by nuclear installations result in uptake in aquatic organisms. The radionuclide uptake model BURN (developed by NRG, modified), considers not only tritium as tritiated water (HTO) but also the conversion into organically bound tritium (OBT). Comparison with the original BURN model showed that the modified model gave more realistic results in terms of concentration levels, and consequently for dose assessment as result of ingestion of fishery products. For more accurate modelling, seasonal effects and half-life estimates as a function of body weight and water temperature must be taken into account. A first attempt is given, although limited empirical data gives reason to further investigation of this significant effect. At present, there are no dynamic models which take into account the metabolic regulation of tritium in plants and animals. In the RODOS system for instance, developed within the EC-project in the past decade, in biological uptake models such as LAKECO (freshwater) and BURN (marine environment) tritium is treated as other radionuclides. Previously the BURN model was modified in order to cope with the metabolic regulation of hydrogen and tritium. In this paper the further development considering seasonality and a metabolic model for OBT loss rate in fish is presented. The importance of considering the specificity of the tritium metabolic pathways was illustrated by comparing the tritium uptake model with the initial BURN model, in which the behaviour of tritium is not different from other radionuclides. Using tritium model, the total tritium concentration in the organism decreased in proportion to the decrease in the river water, to a level where OBT in fish was predominant and slowly varying. Note the difference in the OBT concentration between a winter and a summer release (temperature effect). BURN predicted the integrated total tritium concentration in fish for the first year more than 200 times higher than the
Modeling of the dynamics of wind to power conversion including high wind speed behavior
DEFF Research Database (Denmark)
Litong-Palima, Marisciel; Bjerge, Martin Huus; Cutululis, Nicolaos Antonio
2016-01-01
This paper proposes and validates an efficient, generic and computationally simple dynamic model for the conversion of the wind speed at hub height into the electrical power by a wind turbine. This proposed wind turbine model was developed as a first step to simulate wind power time series...... speed shutdowns and restarts are represented as on–off switching rules that govern the output of the wind turbine at extreme wind speed conditions. The model uses the concept of equivalent wind speed, estimated from the single point (hub height) wind speed using a second-order dynamic filter...... measurements available from the DONG Energy offshore wind farm Horns Rev 2. Copyright © 2015 John Wiley & Sons, Ltd....
Multi-Body Dynamics Including the Effects of Flexibility and Compliance.
1980-04-01
21. Galliday, C. L., Jr., and Hermani, H., "An Approach to Analyzing Biped Locomotion Dynamics and Designing Robot Locomotion Controls," IEEE... robots , manipulators, and teleoperators. 4 ’ 45 T4 REFERENCES 1. Abdelnour, T. A., Passerello, C. E., and Huston, R. L., "An Analytical Analysis of...Synthesis of Biped Locomotion Machines," ed. and Bio. Enstineering, Vol. 8, pp. 465-476, 1970. 20. Frisch, H. P., "A Vector-Dyadic Development of the
International Nuclear Information System (INIS)
Hwang, I.T.; Ting, K.
1987-01-01
Dynamic response of liquid storage tanks considering the hydrodynamic interactions due to earthquake ground motion has been extensively studied. Several finite element procedures, such as Balendra et. al. (1982) and Haroun (1983), have been devoted to investigate the dynamic interaction between the deformable wall of the tank and the liquid. Further, if the geometry of the storage tank can not be described by axi-symmetric case, the tank wall and the fluid domain must be discretized by three dimensional finite elements to investigate the fluid-structure-interactions. Thus, the need of large computer memory and expense of vast computer time usually make this analysis impractical. To demonstrate the accuracy and reliability of the solution technique developed herein, the dynamic behavior of ground-supported, deformed, cylindrical tank with incompressible fluid conducted by Haroun (1983) are analyzed. Good correlations of hydrodynamic pressure distribution between the computed results with the referenced solutions are noted. The fluid compressibility significantly affects the hydrodynamic pressures of the liquid-tank-interactions and the work which is done on this discussion is still little attention. Thus, the influences of the compressibility of the liquid on the reponse of the liquid storage due to ground motion are then drawn. By the way, the complex-valued frequency response functions for hydrodynamic forces of Haroun's problem are also displayed. (orig./GL)
Situational effects of the school factors included in the dynamic model of educational effectiveness
Directory of Open Access Journals (Sweden)
Bert Creemers
2009-08-01
Full Text Available We present results of a longitudinal study in which 50 schools, 113 classes and 2,542 Cypriot primary students participated. We tested the validity of the dynamic model of educational effectiveness and especially its assumption that the impact of school factors depends on the current situation of the school and on the type of problems/difficulties the school is facing. Reference is made to the methods used to test this assumption of the dynamic model by measuring school effectiveness in mathematics, Greek language, and religious education over two consecutive school years. The main findings are as follows. School factors were found to have situational effects. Specifically, the development of a school policy for teaching and the school evaluation of policy for teaching were found to have stronger effects in schools where the quality of teaching at classroom level was low. Moreover, time stability in the effectiveness status of schools was identified and thereby changes in the functioning of schools were found not to have a significant impact on changes in the effectiveness status of schools. Implications of the findings for the development of the dynamic model and suggestions for further research are presented.
Dropwise condensation originating
International Nuclear Information System (INIS)
Croix, J.-M.
1975-01-01
Both principal modes of steam condensation (film or dropwise condensation) are surveyed. Available results are exposed as for contact angle measurements, and the heat transfer mechanisms proposed. The efficiency of the dropwise condensation mode is illustrated from the excellent results obtained in the laboratory by J.M. NIEZBORALA, using an organic compound (fluorinated disulfide) for originating the condensation [fr
The Human Bathtub: Safety and Risk Predictions Including the Dynamic Probability of Operator Errors
International Nuclear Information System (INIS)
Duffey, Romney B.; Saull, John W.
2006-01-01
Reactor safety and risk are dominated by the potential and major contribution for human error in the design, operation, control, management, regulation and maintenance of the plant, and hence to all accidents. Given the possibility of accidents and errors, now we need to determine the outcome (error) probability, or the chance of failure. Conventionally, reliability engineering is associated with the failure rate of components, or systems, or mechanisms, not of human beings in and interacting with a technological system. The probability of failure requires a prior knowledge of the total number of outcomes, which for any predictive purposes we do not know or have. Analysis of failure rates due to human error and the rate of learning allow a new determination of the dynamic human error rate in technological systems, consistent with and derived from the available world data. The basis for the analysis is the 'learning hypothesis' that humans learn from experience, and consequently the accumulated experience defines the failure rate. A new 'best' equation has been derived for the human error, outcome or failure rate, which allows for calculation and prediction of the probability of human error. We also provide comparisons to the empirical Weibull parameter fitting used in and by conventional reliability engineering and probabilistic safety analysis methods. These new analyses show that arbitrary Weibull fitting parameters and typical empirical hazard function techniques cannot be used to predict the dynamics of human errors and outcomes in the presence of learning. Comparisons of these new insights show agreement with human error data from the world's commercial airlines, the two shuttle failures, and from nuclear plant operator actions and transient control behavior observed in transients in both plants and simulators. The results demonstrate that the human error probability (HEP) is dynamic, and that it may be predicted using the learning hypothesis and the minimum
Condensate growth in trapped Bose gates
Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.
2000-01-01
We study the dynamics of condensate fromation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field efects in the condensed and the noncondensed parts of the gas.
Condensate growth in trapped Bose gases
Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.
2000-01-01
We study the dynamics of condensate formation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field effects in the condensed and the noncondensed parts of the gas.
Tunneling of trapped-atom Bose condensates
Indian Academy of Sciences (India)
Tunneling of trapped-atom Bose condensates. SUBODH R SHENOY. Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, Trieste 34100, Italy. Abstract. We obtain the dynamics in number and phase difference, for Bose condensates that tun- nel between two wells of a double-well atomic trap, using the ...
End-To-End Simulation of Launch Vehicle Trajectories Including Stage Separation Dynamics
Albertson, Cindy W.; Tartabini, Paul V.; Pamadi, Bandu N.
2012-01-01
The development of methodologies, techniques, and tools for analysis and simulation of stage separation dynamics is critically needed for successful design and operation of multistage reusable launch vehicles. As a part of this activity, the Constraint Force Equation (CFE) methodology was developed and implemented in the Program to Optimize Simulated Trajectories II (POST2). The objective of this paper is to demonstrate the capability of POST2/CFE to simulate a complete end-to-end mission. The vehicle configuration selected was the Two-Stage-To-Orbit (TSTO) Langley Glide Back Booster (LGBB) bimese configuration, an in-house concept consisting of a reusable booster and an orbiter having identical outer mold lines. The proximity and isolated aerodynamic databases used for the simulation were assembled using wind-tunnel test data for this vehicle. POST2/CFE simulation results are presented for the entire mission, from lift-off, through stage separation, orbiter ascent to orbit, and booster glide back to the launch site. Additionally, POST2/CFE stage separation simulation results are compared with results from industry standard commercial software used for solving dynamics problems involving multiple bodies connected by joints.
Luo, Rutao; Piovoso, Michael J.; Martinez-Picado, Javier; Zurakowski, Ryan
2012-01-01
Mathematical models based on ordinary differential equations (ODE) have had significant impact on understanding HIV disease dynamics and optimizing patient treatment. A model that characterizes the essential disease dynamics can be used for prediction only if the model parameters are identifiable from clinical data. Most previous parameter identification studies for HIV have used sparsely sampled data from the decay phase following the introduction of therapy. In this paper, model parameters are identified from frequently sampled viral-load data taken from ten patients enrolled in the previously published AutoVac HAART interruption study, providing between 69 and 114 viral load measurements from 3–5 phases of viral decay and rebound for each patient. This dataset is considerably larger than those used in previously published parameter estimation studies. Furthermore, the measurements come from two separate experimental conditions, which allows for the direct estimation of drug efficacy and reservoir contribution rates, two parameters that cannot be identified from decay-phase data alone. A Markov-Chain Monte-Carlo method is used to estimate the model parameter values, with initial estimates obtained using nonlinear least-squares methods. The posterior distributions of the parameter estimates are reported and compared for all patients. PMID:22815727
Energy Technology Data Exchange (ETDEWEB)
Raaberg, Martin [Dynasim AB, Lund (Sweden); Tuszynski, Jan [Sycon Energikonsult AB, Malmoe (Sweden)
2002-04-01
The project reported here aimed to test the suitability of existing computer tools for modelling of energy processes. The suggested use for the models are at the early tests and validations of new, refurbished or modernised thermal plants. The technique presented in this report should be applicable for clarification of the scope of delivery and testing for both the process and tile control system. The validation process can thus be simplified, allowing risk reduction and predictability of the commissioning. The main delays and economical misfortune often occurs during commissioning. This report should prove the feasibility of the purchase routines where purchaser, vendor and quality inspection will use a common model of the process to validate system requirements and specifications. Later on it is used to validate structure and predefine testing. Thanks to agreement on the common model, early tests can be conducted on complex systems, minimizing the investment risks. The modelling reported here concerns the direct condenser at Sandvik 11, power and heating plant owned by Vaexjoe Energi AB in Sweden. We have chosen the direct condenser because it is an existing, well-documented and well-defined subsystem of high complexity in both structure and operation. Heavy transients made commissioning and test runs of similar condensers throughout Sweden costly and troublesome. The work resulted in an open, general, and physically correct model. The model can easily be re-dimensioned through physical parameters of common use. The control system modelled corresponds to the actual control system at the Sandvik II plant. Any improvement or deep validation of the controllers was not included in this work. The suitability is shown through four simulation cases. Three cases are based on a registered plant operation during a turbine trip. The first test case uses present plant data, the second an old steam valve actuator and the third uses the old actuator and an error in level
Three-dimensional parallel vortex rings in Bose-Einstein condensates
International Nuclear Information System (INIS)
Crasovan, Lucian-Cornel; Perez-Garcia, Victor M.; Danaila, Ionut; Mihalache, Dumitru; Torner, Lluis
2004-01-01
We construct three-dimensional structures of topological defects hosted in trapped wave fields, in the form of vortex stars, vortex cages, parallel vortex lines, perpendicular vortex rings, and parallel vortex rings, and we show that the latter exist as robust stationary, collective states of nonrotating Bose-Einstein condensates. We discuss the stability properties of excited states containing several parallel vortex rings hosted by the condensate, including their dynamical and structural stability
Directory of Open Access Journals (Sweden)
Korhan Ozgan
2013-01-01
Full Text Available Dynamic analysis of foundation plate-beam systems with transverse shear deformation is presented using modified Vlasov foundation model. Finite element formulation of the problem is derived by using an 8-node (PBQ8 finite element based on Mindlin plate theory for the plate and a 2-node Hughes element based on Timoshenko beam theory for the beam. Selective reduced integration technique is used to avoid shear locking problem for the evaluation of the stiffness matrices for both the elements. The effect of beam thickness, the aspect ratio of the plate and subsoil depth on the response of plate-beam-soil system is analyzed. Numerical examples show that the displacement, bending moments and shear forces are changed significantly by adding the beams.
Research progress of control of condensate depression for condenser
Liu, Ying; Liang, Run; Li, Fengyu
2017-08-01
It is introduced that significance and structure of the condensate depression control system. In accordance with controller devised procedure, we analyze and elaborate how to construct the lumped parameter and dynamic mathematical model which possesses distinct physics significance. Neural network model being called black-box model is also introduced. We analyze and contrast the control technique of condensate depression as conventional PI control, fuzzy PI control and fuzzy control. It is indicated that if the controller of condensate depression were devised inappropriate, while the steam discharged of turbine varying by a large margin, would result in the rotation rate of cooling water circulating pump accelerating at a great lick even to trigger the galloping danger which is less impressive for the units operating safely.
Duran-Olivencia, Miguel A.; Goddard, Ben; Kalliadasis, Serafim
2015-11-01
Over the last few decades the classical density-functional theory (DFT) and its dynamic extensions (DDFTs) have become a remarkably powerful tool in the study of colloidal fluids. Recently there has been extensive research to generalise all previous DDFTs finally yielding a general DDFT equation (for spherical particles) which takes into account both inertia and hydrodynamic interactions (HI) which strongly influence non-equilibrium properties. The present work will be devoted to a further generalisation of such a framework to systems of anisotropic particles. To this end, the kinetic equation for the Brownian particle distribution function is derived starting from the Liouville equation and making use of Zwanzig's projection-operator techniques. By averaging over all but one particle, a DDFT equation is finally obtained with some similarities to that for spherical colloids. However, there is now an inevitable translational-rotational coupling which affects the diffusivity of asymmetric particles. Lastly, in the overdamped (high friction) limit the theory is notably simplified leading to a DDFT equation which agrees with previous derivations. We acknowledge financial support from European Research Council via Advanced Grant No. 247031.
International Nuclear Information System (INIS)
Masumitsu, Isao; Ito, Tomoaki; Kajio, Shozo; Takayama, Toshio; Ishikawa, Yasuyuki
1992-01-01
Condensate treatment system is installed for purifying condensate in thermal and nuclear power stations. Once-through boilers appeared, and in order to maintain the high purity water quality of condensate, condensate desalting facilities were installed in 1962 in Japan. There are the single type using condensate desalting facility only and the combined type of condensate prefilter and condensate desalting facility. The purpose of installing condensate treatment system is to remove corrosion products and ion components generated from the structural materials of plants and to remove sea water composition if it leaks. The general steam-condensate system in thermal power plants is explained. A standard JIS B 8223 'Quality of feedwater and boiler water for boilers' is instituted. The water treatment for boilers is carried out by the treatment of makeup feed, chemical treatment in boilers and blow. In the case of once-through boilers, blow cannot be done, accordingly, very high purity water is required. Condensate prefilter, condensate desalting facility, the watching of condensate treatment system and the operation in combined water treatment are reported. Also the condensate prefilters and the condensate desalting facilities for BWR and PWR plants are described. (K.I.)
Recent developments in Bose-Einstein condensation
Energy Technology Data Exchange (ETDEWEB)
Kalman, G.
1997-09-22
This paper contains viewgraphs on developments on Bose-Einstein condensation. Some topics covered are: strongly coupled coulomb systems; standard response functions of the first and second kind; dynamical mean field theory; quasi localized charge approximation; and the main equations.
Enhanced UWB Radio Channel Model for Short-Range Communication Scenarios Including User Dynamics
DEFF Research Database (Denmark)
Kovacs, Istvan Zsolt; Nguyen, Tuan Hung; Eggers, Patrick Claus F.
2005-01-01
channel model represents an enhancement of the existing IEEE 802.15.3a/4a PAN channel model, where antenna and user-proximity effects are not included. Our investigations showed that significant variations of the received wideband power and time-delay signal clustering are possible due the human body...
Lin, Raymond Chao
The handling qualities evaluation of nonlinear aircraft systems is an area of concern in loss-of-control (LOC) prevention. The Get Transfer Function (GetTF) method was demonstrated for evaluating the handling qualities of flight control systems and aircraft containing nonlinearities. NASA's Generic Transport Model (GTM), a nonlinear model of a civilian jet transport aircraft, was evaluated. Using classical techniques, the stability, control, and augmentation (SCAS) systems were designed to control pitch rate, roll rate, and airspeed. Hess's structural pilot model was used to model pilot dynamics in pitch and roll-attitude tracking. The simulated task was simultaneous tracking of, both, pitch and roll attitudes. Eight cases were evaluated: 1) gain increase of pitch-attitude command signal, 2) gain increase of roll-attitude command signal, 3) gain reduction of elevator command signal, 4) backlash in elevator actuator, 5) combination 3 and 4 in elevator actuator, 6) gain reduction of aileron command signal, 7) backlash in aileron actuator, and 8) combination of 6 and 7 in aileron actuator. The GetTF method was used to estimate the transfer function approximating a linear relationship between the proprioceptive signal of the pilot model and the command input. The transfer function was then used to predict the handling qualities ratings (HQR) and pilot-induced oscillation ratings (PIOR). The HQR is based on the Cooper-Harper rating scale. In pitch-attitude tracking, the nominal aircraft is predicted to have Level 2* HQRpitch and 2 exercise was also conducted to validate the structural pilot model.
Dynamic 2D-barcodes for multi-device Web session migration including mobile phones
DEFF Research Database (Denmark)
Alapetite, Alexandre
2010-01-01
are covered in the article, including a possible migration from a mobile device to a computer (opposite direction), and between two or more mobile phones (possibly back and forth). The results show that this HCI approach is inexpensive, efficient, and works with most camera-phones on the market; the author......This article introduces a novel Web architecture that supports session migration in multi-device Web applications, particularly the case when a user starts a Web session on a computer and wishes to continue on a mobile phone. The proposed solution for transferring the needed session identifiers...
Dynamic elastic-plastic behaviour of a frame including coupled bending and torsion
International Nuclear Information System (INIS)
Messmer, S.; Sayir, M.
1989-01-01
The full time response of a space frame under impact loading perpendicular to the frame plane is discussed. Theoretical solutions and experimental results are presented and compared. A space frame clamped at its two ends is loaded by a 0.22 lead bullet that hits a mass in the middle of the transversal beam of the frame. The loading time is about 40 to 60 μs and the resulting linear momentum of the impact in the experiment is 0.5 to 1 N s. The time response of this frame can be divided in four phases where different physical effects are dominant: (a) The loading phase where elastic wave motion dominates the time response. Because of the high impact forces, plastic deformation occurs in the vicinity of the mass and must be included in a theoretical model. The influence of reflections at the corners on the time response is shown in theory and experiment. (b) The evolution phase. Within this phase, a plastic collapse mechanism develops. Most of this phase is dominated by elastic deformation but local plastic deformations beside the mass are also present. Because many reflections at corners, clamps and the mass occur within this phase, a modal analysis method is used to predict time histories. (c) The plastic phase with plastic zones at the clamps. The phase sets in after the bending wave reaches the clamps. It is characterized by plastic deformation near the clamps and elastic deformation of the other parts of the frame. We used a modal analysis including plastic 'modes' to get accurate results. (d) The elastic vibration phase
Ge, Ni-Na; Wei, Yong-Kai; Song, Zhen-Fei; Chen, Xiang-Rong; Ji, Guang-Fu; Zhao, Feng; Wei, Dong-Qing
2014-07-24
Molecular dynamics simulations in conjunction with multiscale shock technique (MSST) are performed to study the initial chemical processes and the anisotropy of shock sensitivity of the condensed-phase HMX under shock loadings applied along the a, b, and c lattice vectors. A self-consistent charge density-functional tight-binding (SCC-DFTB) method was employed. Our results show that there is a difference between lattice vector a (or c) and lattice vector b in the response to a shock wave velocity of 11 km/s, which is investigated through reaction temperature and relative sliding rate between adjacent slipping planes. The response along lattice vectors a and c are similar to each other, whose reaction temperature is up to 7000 K, but quite different along lattice vector b, whose reaction temperature is only up to 4000 K. When compared with shock wave propagation along the lattice vectors a (18 Å/ps) and c (21 Å/ps), the relative sliding rate between adjacent slipping planes along lattice vector b is only 0.2 Å/ps. Thus, the small relative sliding rate between adjacent slipping planes results in the temperature and energy under shock loading increasing at a slower rate, which is the main reason leading to less sensitivity under shock wave compression along lattice vector b. In addition, the C-H bond dissociation is the primary pathway for HMX decomposition in early stages under high shock loading from various directions. Compared with the observation for shock velocities V(imp) = 10 and 11 km/s, the homolytic cleavage of N-NO2 bond was obviously suppressed with increasing pressure.
2011-01-01
Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS) model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV) loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves. PMID:21942971
Directory of Open Access Journals (Sweden)
Moonen Marie
2011-09-01
Full Text Available Abstract Background Valve dysfunction is a common cardiovascular pathology. Despite significant clinical research, there is little formal study of how valve dysfunction affects overall circulatory dynamics. Validated models would offer the ability to better understand these dynamics and thus optimize diagnosis, as well as surgical and other interventions. Methods A cardiovascular and circulatory system (CVS model has already been validated in silico, and in several animal model studies. It accounts for valve dynamics using Heaviside functions to simulate a physiologically accurate "open on pressure, close on flow" law. However, it does not consider real-time valve opening dynamics and therefore does not fully capture valve dysfunction, particularly where the dysfunction involves partial closure. This research describes an updated version of this previous closed-loop CVS model that includes the progressive opening of the mitral valve, and is defined over the full cardiac cycle. Results Simulations of the cardiovascular system with healthy mitral valve are performed, and, the global hemodynamic behaviour is studied compared with previously validated results. The error between resulting pressure-volume (PV loops of already validated CVS model and the new CVS model that includes the progressive opening of the mitral valve is assessed and remains within typical measurement error and variability. Simulations of ischemic mitral insufficiency are also performed. Pressure-Volume loops, transmitral flow evolution and mitral valve aperture area evolution follow reported measurements in shape, amplitude and trends. Conclusions The resulting cardiovascular system model including mitral valve dynamics provides a foundation for clinical validation and the study of valvular dysfunction in vivo. The overall models and results could readily be generalised to other cardiac valves.
Condensate and feedwater systems, pumps, and water chemistry. Volume seven
International Nuclear Information System (INIS)
Anon.
1986-01-01
Subject matter includes condensate and feedwater systems (general features of condensate and feedwater systems, condenser hotwell level control, condensate flow, feedwater flow), pumps (principles of fluid flow, types of pumps, centrifugal pumps, positive displacement pumps, jet pumps, pump operating characteristics) and water chemistry (water chemistry fundamentals, corrosion, scaling, radiochemistry, water chemistry control processes, water pretreatment, PWR water chemistry, BWR water chemistry, condenser circulating water chemistry
Condensed Matter Nuclear Science
Biberian, Jean-Paul
2006-02-01
of analysis of Ti foil after glow discharge with deuterium / I. B. Savvatimova and D. V. Gavritenkov. Enhancement mechanisms of low-energy nuclear reactions / F. A. Gareev, I. E. Zhidkova, and Y. L. Ratis. Co-deposition of palladium with hydrogen isotopes / J. Dash and A. Ambadkar. Variation of the concentration of isotopes copper and zinc in human plasmas of patients affected by cancer / A. Triassi. Transmutation of metal at low energy in a confined plasma in water / D. Cirillo and V. Iorio. The conditions and realization of self-similar Coulomb collapse of condensed target and low-energy laboratory nucleosynthesis / S. V. Adamenko and V. I. Vysotskii. The spatial structure of water and the problem of controlled low-energy nuclear reactions in water matrix / V. I. Vysotskii and A. A. Kornilova. Experiments on controlled decontamination of water mixture of longlived active isotopes in biological cells / V. I. Vysotskii. Assessment of the biological effects of "strange" radiation / E. A. Pryakhin ... [et al.]. Possible nuclear transmutation of nitrogen in the earth's atmosphere / M. Fukuhara. Evidences on the occurrence of LENR-type processes in alchemical transmutations / J. Pérez-Pariente. History of the discovery of transmutation at Texas A&M University / J. O.-M. Bockris -- 4. Theory. Quantum electrodynamics. Concerning the modeling of systems in terms of quantum electro dynamics: the special case of "cold fusion" / M. Abyaneh ... [et al.]. Screening. Theoretical model of the probability of fusion between deuterons within deformed lattices with microcracks at room temperature / F. Fulvio. Resonant tunnelling. Effective interaction potential in the deuterium plasma and multiple resonance scattering / T. Toimela. Multiple scattering theory and condensed matter nuclear science - "super-absorption" in a crystal latice / X. Z. Li ... [et al.]. Ion band states. Framework for understanding LENR processes, using conventional condensed matter physics / S. R. Chubb. I
International Nuclear Information System (INIS)
Jones, Richard A L
2002-01-01
and formulated through the current percolation model and the Flory-Stockmayer model. The next two chapters consider the molecular order in soft condensed matter. The rich complexity of liquid crystals is emphasized and the Frederiks transition is described in relation to liquid crystal displays. The crystallinity in polymers is discussed and its usual semi-crystallinity presented as a consequence of entanglement and timescales. The next chapter describes the self-assembly of phases and the great importance of the self-assembly phenomenon in solutions of amphiphilic molecules is largely discussed in several specific phenomena. The book ends with a chapter devoted to the description of soft matter realizations in nature. Special attention is paid to the components and structure of life: nucleic acids, proteins, polysaccharides and membranes. There are two appendixes recalling the basic concepts of thermodynamics and statistical mechanics. In each chapter, several problems are included, and solutions to a selection of them are given. The bibliography proposed is pertinent and each chapter gives details of further reading, mostly addressed to known books on the topic. The presentation of the book is good. Throughout the book, the relevant, basic or new concepts of each topic are typed in bold characters and succinctly defined. The figures are abundant and adequately illustrate the text either by plots of experimental data or by computed predictions from models. Many schematic representations of structures, molecular distributions or arrangements are also included. In summary, the author has succeeded in producing a scientifically rigorous book of affordable size (around 200 pages) that is well illustrated (about 120 figures) and written in a fluent style that describes the many different physical phenomena involved in soft condensed matter. (book review)
Ice condenser experimental plan
International Nuclear Information System (INIS)
Kannberg, L.D.; Piepel, G.F.; Owczarski, P.C.; Liebetrau, A.M.
1986-01-01
An experimental plan is being developed to validate the computer code ICEDF. The code was developed to estimate the extent of aerosol retention in the ice compartments of pressurized water reactor ice condenser containment systems during severe accidents. The development of the experimental plan began with review of available information on the conditions under which the code will be applied. Computer-generated estimates of thermohydraulic and aerosol conditions entering the ice condenser were evaluated and along with other information, used to generate design criteria. The design criteria have been used for preliminary test assembly design and for generation of statistical test designs. Consideration of the phenomena to be evaluated in the testing program, as well as equipment and measurement limitations, have led to changes in the design criteria and to subsequent changes in the test assembly design and statistical test design. The overall strategy in developing the experimental plan includes iterative generation and evaluation of candidate test designs using computer codes for statistical test design and ICEDF for estimation of experimental results. Estimates of experimental variability made prior to actual testing will be verified by replicate testing at preselected design points
Energy Technology Data Exchange (ETDEWEB)
Zerfass, Christian; Buchko, Garry W.; Shaw, Wendy J.; Hobe, Stephan; Paulsen, Harold
2017-08-24
The silica forming repeat R5 of sil1 from Cylindrotheca fusiformis was the blueprint for the design of P5S3, a 50-residue peptide which can be produced in large amounts by recombinant bacterial expression. It contains five protein kinase A target sites and is highly cationic due to 10 lysine and 10 arginine residues. In the presence of supersaturated ortho silicic acid P5S3 strongly enhances silica-formation whereas it retards the dissolution of amorphous silica (SiO2) at globally undersaturated concentrations. The secondary structure of P5S3 during these different functions was studied by circular dichroism (CD), complemented by nuclear magnetic resonance (NMR) studies of the peptide in the absence of silicate. The NMR studies of dual-labeled (13C, 15N) P5S3 revealed a disordered structure at pH 2.8 and 4.5. Within the pH range of 4.5 to 9.5, the CD data verified the disordered secondary structure but also suggested the presence of some polyproline II character in the absence of silicic acid. Upon silicic acid polymerization and during dissolution of preformed silica, the CD spectrum of P5S3 indicated partial transition into an α-helical conformation which was transient during silica-dissolution. Consequently, the secondary structural changes observed for P5S3 correlate with the presence of oli-gomeric/polymeric silicic acid, presumably due to P5S3-silicic acid interactions. These interactions appear, at least in part, ionic in nature since dodecylsulfate micelles, which are negatively charged, cause similar conformational shifts to P5S3 in the absence of silica while ß-D-dodecyl maltoside micelles, which are neutral, do not. Thus, P5S3 influences both the condensation of silicic acid into silica and its decondensation back to silicic acid. Moreover, the dynamics of these pro-cesses may be indirectly monitored by following structural changes to P5S3 with CD spectroscopy.
International Nuclear Information System (INIS)
Yamamoto, Michiyoshi; Oosumi, Katsumi; Takashima, Yoshie; Mitani, Shinji.
1982-01-01
Purpose: To decrease the frequency for the backwash and regeneration operations due to the increase in the differential pressure resulted from claddings captured in a mixed floor type desalter, and decrease the amount of radioactive liquid wastes of claddings from the condensate systems by removing claddings with electromagnetic filters. Constitution: In an existent plant, a valves is disposed between a condensate pump and a mixed floor type desalter. A pipeway is branched from a condensate pipe between the condensate pipe and the valve, through which condensates are transferred by a pump to an electromagnetic filter such as of a high gradient type electromagntic filter to remove claddings, then returned to a condensate pipe between the valve and the mixed floor type desalter and, thereafter, are removed with ionic components in the mixed floor type desalter and fed to the reactor. (Yoshino, Y.)
Soliton resonance in bose-einstein condensate
Zak, Michail; Kulikov, I.
2002-01-01
A new phenomenon in nonlinear dispersive systems, including a Bose-Einstein Condensate (BEC), has been described. It is based upon a resonance between an externally induced soliton and 'eigen-solitons' of the homogeneous cubic Schrodinger equation. There have been shown that a moving source of positive /negative potential induces bright /dark solitons in an attractive / repulsive Bose condensate.
Tunneling of trapped-atom Bose condensates
Indian Academy of Sciences (India)
Abstract. We obtain the dynamics in number and phase difference, for Bose condensates that tun- nel between two wells of a double-well atomic trap, using the (nonlinear) Gross–Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamil- tonian corresponds to that ...
Tunneling of trapped-atom Bose condensates
Indian Academy of Sciences (India)
We obtain the dynamics in number and phase difference, for Bose condensates that tunnel between two wells of a double-well atomic trap, using the (nonlinear) Gross–Pitaevskii equation. The dynamical equations are of the canonical form for the two conjugate variables, and the Hamiltonian corresponds to that of a ...
Scrutinizing the pion condensed phase
Energy Technology Data Exchange (ETDEWEB)
Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)
2017-02-15
When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)
On inflation in the presence of a gaugino condensate
International Nuclear Information System (INIS)
Lebedev, Oleg; Papineau, Chloe
2009-07-01
We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)
On inflation in the presence of a gaugino condensate
International Nuclear Information System (INIS)
Lebedev, Oleg; Papineau, Chloe; Postma, Marieke
2010-01-01
We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.
On inflation in the presence of a gaugino condensate
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Oleg; Papineau, Chloe [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Theory Group; Postma, Marieke [NIKHEF, Amsterdam (Netherlands)
2009-07-15
We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe. (orig.)
On inflation in the presence of a gaugino condensate
Energy Technology Data Exchange (ETDEWEB)
Lebedev, Oleg [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Papineau, Chloe, E-mail: chloe.papineau@desy.d [DESY Theory Group, Notkestrasse 85, D-22607 Hamburg (Germany); Postma, Marieke [NIKHEF, Kruislaan 409, 1098 Amsterdam (Netherlands)
2010-02-08
We study the effect of inflation on gaugino condensation in supergravity. Unless the Hubble scale H is significantly below the gaugino condensation scale, the gaugino condensate is a dynamical variable which cannot be integrated out. For a sufficiently high H, the gaugino condensate evolves to zero which in turn leads to dilaton/moduli destabilization. In practice, this often occurs at the Hubble rate about an order of magnitude below the gaugino condensation scale. This effect is independent of the specifics of moduli stabilization and thus places model-independent constraints on inflationary scenarios. It also applies more generally to any periods of fast expansion in the early Universe.
Gluon condensation and modelling of quark confinement in QCD-motivated Nambu-Jona-Lasinio model
International Nuclear Information System (INIS)
Bel'kov, A.A.; Ebert, D.; Emel'yanenko, A.V.
1992-01-01
The possibility of modelling of a quark propagator without poles realizing quark confinement is considered on the basis of a nonperturbative gluon propagator including gluon condensation and a dynamical gluon mass. The property of spontaneous chiral symmetry breaking is retained providing us with a reasonable pattern of low-lying meson properties. 2 figs.; 1 tab
Condensed matter analogues of cosmology
Kibble, Tom; Srivastava, Ajit
2013-10-01
It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the
Pamadi, Bandu N.; Toniolo, Matthew D.; Tartabini, Paul V.; Roithmayr, Carlos M.; Albertson, Cindy W.; Karlgaard, Christopher D.
2016-01-01
The objective of this report is to develop and implement a physics based method for analysis and simulation of multi-body dynamics including launch vehicle stage separation. The constraint force equation (CFE) methodology discussed in this report provides such a framework for modeling constraint forces and moments acting at joints when the vehicles are still connected. Several stand-alone test cases involving various types of joints were developed to validate the CFE methodology. The results were compared with ADAMS(Registered Trademark) and Autolev, two different industry standard benchmark codes for multi-body dynamic analysis and simulations. However, these two codes are not designed for aerospace flight trajectory simulations. After this validation exercise, the CFE algorithm was implemented in Program to Optimize Simulated Trajectories II (POST2) to provide a capability to simulate end-to-end trajectories of launch vehicles including stage separation. The POST2/CFE methodology was applied to the STS-1 Space Shuttle solid rocket booster (SRB) separation and Hyper-X Research Vehicle (HXRV) separation from the Pegasus booster as a further test and validation for its application to launch vehicle stage separation problems. Finally, to demonstrate end-to-end simulation capability, POST2/CFE was applied to the ascent, orbit insertion, and booster return of a reusable two-stage-to-orbit (TSTO) vehicle concept. With these validation exercises, POST2/CFE software can be used for performing conceptual level end-to-end simulations, including launch vehicle stage separation, for problems similar to those discussed in this report.
Wai, Rong-Jong; Yang, Zhi-Wei
2008-10-01
This paper focuses on the development of adaptive fuzzy neural network control (AFNNC), including indirect and direct frameworks for an n-link robot manipulator, to achieve high-precision position tracking. In general, it is difficult to adopt a model-based design to achieve this control objective due to the uncertainties in practical applications, such as friction forces, external disturbances, and parameter variations. In order to cope with this problem, an indirect AFNNC (IAFNNC) scheme and a direct AFNNC (DAFNNC) strategy are investigated without the requirement of prior system information. In these model-free control topologies, a continuous-time Takagi-Sugeno (T-S) dynamic fuzzy model with online learning ability is constructed to represent the system dynamics of an n-link robot manipulator. In the IAFNNC, an FNN estimator is designed to tune the nonlinear dynamic function vector in fuzzy local models, and then, the estimative vector is used to indirectly develop a stable IAFNNC law. In the DAFNNC, an FNN controller is directly designed to imitate a predetermined model-based stabilizing control law, and then, the stable control performance can be achieved by only using joint position information. All the IAFNNC and DAFNNC laws and the corresponding adaptive tuning algorithms for FNN weights are established in the sense of Lyapunov stability analyses to ensure the stable control performance. Numerical simulations and experimental results of a two-link robot manipulator actuated by dc servomotors are given to verify the effectiveness and robustness of the proposed methodologies. In addition, the superiority of the proposed control schemes is indicated in comparison with proportional-differential control, fuzzy-model-based control, T-S-type FNN control, and robust neural fuzzy network control systems.
DEFF Research Database (Denmark)
Malterud, Kirsti
2012-01-01
To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies.......To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies....
International Nuclear Information System (INIS)
Jaksch, D
2003-01-01
The Gross-Pitaevskii equation, named after one of the authors of the book, and its large number of applications for describing the properties of Bose-Einstein condensation (BEC) in trapped weakly interacting atomic gases, is the main topic of this book. In total the monograph comprises 18 chapters and is divided into two parts. Part I introduces the notion of BEC and superfluidity in general terms. The most important properties of the ideal and the weakly interacting Bose gas are described and the effects of nonuniformity due to an external potential at zero temperature are studied. The first part is then concluded with a summary of the properties of superfluid He. In Part II the authors describe the theoretical aspects of BEC in harmonically trapped weakly interacting atomic gases. A short and rather rudimentary chapter on collisions and trapping of atomic gases which seems to be included for completeness only is followed by a detailed analysis of the ground state, collective excitations, thermodynamics, and vortices as well as mixtures of BECs and the Josephson effect in BEC. Finally, the last three chapters deal with topics of more recent interest like BEC in optical lattices, low dimensional systems, and cold Fermi gases. The book is well written and in fact it provides numerous useful and important relations between the different properties of a BEC and covers most of the aspects of ultracold weakly interacting atomic gases from the point of view of condensed matter physics. The book contains a comprehensive introduction to BEC for physicists new to the field as well as a lot of detail and insight for those already familiar with this area. I therefore recommend it to everyone who is interested in BEC. Very clearly however, the intention of the book is not to provide prospects for applications of BEC in atomic physics, quantum optics or quantum state engineering and therefore the more practically oriented reader might sometimes wonder why exactly an equation is
Chromosome condensation and segmentation
International Nuclear Information System (INIS)
Viegas-Pequignot, E.M.
1981-01-01
Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr
Condensation in complex geometries
International Nuclear Information System (INIS)
Lauro, F.
1975-01-01
A mathematical evaluation of the condensation exchange coefficient can only succeds for well specified cases: small upright or inclined plates, horizontal tubes, small height vertical tubes. Among the main hypotheses accounted for this mathematical development in the case of the condensate, a laminar flow and uniform surface temperature are always considered. In practice certain shapes of surfaces significantly increase the heat transfer during the vapor condensation on a surface wet by the condensate. Such surfaces are rough surfaces such as the condensate is submitted to surface tension effects, negligeable for plane or large curvature surfaces, and the nature of the material may play an important role (temperature gradients). Results from tests on tubes with special shapes, performed in France or out of France, are given [fr
Huang, T W; Zhou, C T; He, X T
2013-05-01
Plasma defocusing and higher-order Kerr effects on multiple filamentation and pattern formation of ultrashort laser pulse propagation in air are investigated. Linear analyses and numerical results show that these two saturable nonlinear effects can destroy the coherent evolution of the laser field, and small-scale spatial turbulent structures rapidly appear. For the two-dimensional case, numerical simulations show that blow-up-like solutions, spatial chaos, and pseudorecurrence can appear at higher laser intensities if only plasma defocusing is included. These complex patterns result from the stochastic evolution of the higher- or shorter-wavelength modes of the laser light spectrum. From the viewpoint of nonlinear dynamics, filamentation can be attributed to the modulational instability of these spatial incoherent localized structures. Furthermore, filament patterns associated with multiphoton ionization of the air molecules with and without higher-order Kerr effects are compared.
Holography, Gravity and Condensed Matter
Energy Technology Data Exchange (ETDEWEB)
Hartnoll, Sean [Stanford Univ., CA (United States). Dept. of Physics
2017-12-20
Over the five years of funding from this grant, I produced 26 publications. These include a book-long monograph on "Holographic Quantum Matter" that is currently in press with MIT press. The remainder were mostly published in Physical Review Letters, the Journal of High Energy Physics, Nature Physics, Classical and Quantum Gravity and Physical Review B. Over this period, the field of holography applied to condensed matter physics developed from a promising theoretical approach to a mature conceptual and practical edifice, whose ideas were realized in experiments. My own work played a central role in this development. In particular, in the final year of this grant, I co-authored two experimental papers in which ideas that I had developed in earlier years were shown to usefully describe transport in strongly correlated materials — these papers were published in Science and in the Proceedings of the National Academy of Sciences (obviously my contribution to these papers was theoretical). My theoretical work in this period developed several new directions of research that have proven to be influential. These include (i) The construction of highly inhomogeneous black hole event horizons, realizing disordered fixed points and describing new regimes of classical gravity, (ii) The conjecture of a bound on diffusivities that could underpin transport in strongly interacting media — an idea which may be proven in the near future and has turned out to be intimately connected to studies of quantum chaos in black holes and strongly correlated media, (iii) The characterization of new forms of hydrodynamic transport, e.g. with phase-disordered order parameters. These studies pertain to key open questions in our understanding of how non-quasiparticle, intrinsically strongly interacting systems can behave. In addition to the interface between holography and strongly interacting condensed matter systems, I made several advances on understanding the role of entanglement in quantum
Film condensation on non-isothermal vertical plates
Brouwers, Jos
1989-01-01
An analytical study is presented of the condensation of a pure saturated vapour on a cooled channel plate, including the interaction between the cooling liquid, the condensate and the vapour. The governing equations of co-, counter- and cross-current condensation are derived, set dimensionless and
Dynamical behaviors of Rb-E2F pathway including negative feedback loops involving miR449.
Yan, Fang; Liu, Haihong; Hao, Junjun; Liu, Zengrong
2012-01-01
MiRNAs, which are a family of small non-coding RNAs, regulate a broad array of physiological and developmental processes. However, their regulatory roles have remained largely mysterious. E2F is a positive regulator of cell cycle progression and also a potent inducer of apoptosis. Positive feedback loops in the regulation of Rb-E2F pathway are predicted and shown experimentally. Recently, it has been discovered that E2F induce a cluster of miRNAs called miR449. In turn, E2F is inhibited by miR449 through regulating different transcripts, thus forming negative feedback loops in the interaction network. Here, based on the integration of experimental evidence and quantitative data, we studied Rb-E2F pathway coupling the positive feedback loops and negative feedback loops mediated by miR449. Therefore, a mathematical model is constructed based in part on the model proposed in Yao-Lee et al. (2008) and nonlinear dynamical behaviors including the stability and bifurcations of the model are discussed. A comparison is given to reveal the implication of the fundamental differences of Rb-E2F pathway between regulation and deregulation of miR449. Coherent with the experiments it predicts that miR449 plays a critical role in regulating the cell cycle progression and provides a twofold safety mechanism to avoid excessive E2F-induced proliferation by cell cycle arrest and apoptosis. Moreover, numerical simulation and bifurcation analysis shows that the mechanisms of the negative regulation of miR449 to three different transcripts are quite distinctive which needs to be verified experimentally. This study may help us to analyze the whole cell cycle process mediated by other miRNAs more easily. A better knowledge of the dynamical behaviors of miRNAs mediated networks is also of interest for bio-engineering and artificial control.
Dynamical behaviors of Rb-E2F pathway including negative feedback loops involving miR449.
Directory of Open Access Journals (Sweden)
Fang Yan
Full Text Available MiRNAs, which are a family of small non-coding RNAs, regulate a broad array of physiological and developmental processes. However, their regulatory roles have remained largely mysterious. E2F is a positive regulator of cell cycle progression and also a potent inducer of apoptosis. Positive feedback loops in the regulation of Rb-E2F pathway are predicted and shown experimentally. Recently, it has been discovered that E2F induce a cluster of miRNAs called miR449. In turn, E2F is inhibited by miR449 through regulating different transcripts, thus forming negative feedback loops in the interaction network. Here, based on the integration of experimental evidence and quantitative data, we studied Rb-E2F pathway coupling the positive feedback loops and negative feedback loops mediated by miR449. Therefore, a mathematical model is constructed based in part on the model proposed in Yao-Lee et al. (2008 and nonlinear dynamical behaviors including the stability and bifurcations of the model are discussed. A comparison is given to reveal the implication of the fundamental differences of Rb-E2F pathway between regulation and deregulation of miR449. Coherent with the experiments it predicts that miR449 plays a critical role in regulating the cell cycle progression and provides a twofold safety mechanism to avoid excessive E2F-induced proliferation by cell cycle arrest and apoptosis. Moreover, numerical simulation and bifurcation analysis shows that the mechanisms of the negative regulation of miR449 to three different transcripts are quite distinctive which needs to be verified experimentally. This study may help us to analyze the whole cell cycle process mediated by other miRNAs more easily. A better knowledge of the dynamical behaviors of miRNAs mediated networks is also of interest for bio-engineering and artificial control.
Condensed matter research using pulsed neutron sources: a bibliography
International Nuclear Information System (INIS)
Mildner, D.F.R.; Stirling, G.C.
1976-05-01
This report is an updated revision of RL-75-095 'Condensed Matter Research Using Pulsed Neutron Sources: A Bibliography'. As before, the survey lists published papers concerning (a) the production of high intensity neutron pulses suitable for thermal neutron scattering research, (b) moderating systems for neutron thermalization and pulse shaping, (c) techniques and instrumentation for diffraction and inelastic scattering at pulsed sources, and (d) their application to research problems concerning the structural and dynamical properties of condensed matter. Papers which deal with the white beam time-of-flight technique at steady state reactors have also been included. A number of scientists have brought to the author's attention papers which have been published since the previous edition. They are thanked and encouraged to continue the cooperation so that the bibliography may be updated periodically. (author)
National Research Council Canada - National Science Library
Ameel, Timothy
1999-01-01
.... Evaporators and condensers for meso-scale energy systems will most likely be constructed of microchannels due to the microfabrication constraints that limit most structures to two-dimensional planar geometries...
Min, Byeng R; Solaiman, Sandra; Shange, Raymon; Eun, Jong-Su
2014-01-01
Eighteen Kiko-cross meat goats (n = 6) were used to collect gastrointestinal (GI) bacteria and methanogenic archaea for diversity measures when fed condensed tannin-containing pine bark (PB). Three dietary treatments were tested: control diet (0% PB and 30% wheat straw (WS); 0.17% condensed tannins (CT) dry matter (DM)); 15% PB and 15% WS (1.6% CT DM), and 30% PB and 0% WS (3.2% CT DM). A 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing technique was used to characterize and elucidate changes in GI bacteria and methanogenic archaea diversity among the diets. Proteobacteria was the most dominant phylum in goats with mean relative abundance values ranging from 39.7 (30% PB) to 46.5% (control) and 47.1% (15% PB). Other phyla individually accounted for fewer than 25% of the relative abundance observed. Predominant methanogens were Methanobrevibacter (75, 72, and 49%), Methanosphaera (3.3, 2.3, and 3.4%), and Methanobacteriaceae (1.2, 0.6, and 0.7%) population in control, 15, and 30% PB, respectively. Among methanogens, Methanobrevibacter was linearly decreased (P = 0.05) with increasing PB supplementation. These results indicate that feeding PB selectively altered bacteria and methanogenic archaeal populations in the GI tract of goats.
Directory of Open Access Journals (Sweden)
Byeng R. Min
2014-01-01
Full Text Available Eighteen Kiko-cross meat goats (n=6 were used to collect gastrointestinal (GI bacteria and methanogenic archaea for diversity measures when fed condensed tannin-containing pine bark (PB. Three dietary treatments were tested: control diet (0% PB and 30% wheat straw (WS; 0.17% condensed tannins (CT dry matter (DM; 15% PB and 15% WS (1.6% CT DM, and 30% PB and 0% WS (3.2% CT DM. A 16S rDNA bacterial tag-encoded FLX amplicon pyrosequencing technique was used to characterize and elucidate changes in GI bacteria and methanogenic archaea diversity among the diets. Proteobacteria was the most dominant phylum in goats with mean relative abundance values ranging from 39.7 (30% PB to 46.5% (control and 47.1% (15% PB. Other phyla individually accounted for fewer than 25% of the relative abundance observed. Predominant methanogens were Methanobrevibacter (75, 72, and 49%, Methanosphaera (3.3, 2.3, and 3.4%, and Methanobacteriaceae (1.2, 0.6, and 0.7% population in control, 15, and 30% PB, respectively. Among methanogens, Methanobrevibacter was linearly decreased (P=0.05 with increasing PB supplementation. These results indicate that feeding PB selectively altered bacteria and methanogenic archaeal populations in the GI tract of goats.
Directory of Open Access Journals (Sweden)
Laurent Coudeville
Full Text Available BACKGROUND: Prior economic evaluations of adult and adolescent vaccination strategies against pertussis have reached disparate conclusions. Using static approaches only, previous studies failed to analytically include the indirect benefits derived from herd immunity as well as the impact of vaccination on the evolution of disease incidence over time. METHODS: We assessed the impact of different pertussis vaccination strategies using a dynamic compartmental model able to consider pertussis transmission. We then combined the results with economic data to estimate the relative cost-effectiveness of pertussis immunization strategies for adolescents and adults in the US. The analysis compares combinations of programs targeting adolescents, parents of newborns (i.e. cocoon strategy, or adults of various ages. RESULTS: In the absence of adolescent or adult vaccination, pertussis incidence among adults is predicted to more than double in 20 years. Implementing an adult program in addition to childhood and adolescent vaccination either based on 1 a cocoon strategy and a single booster dose or 2 a decennial routine vaccination would maintain a low level of pertussis incidence in the long run for all age groups (respectively 30 and 20 cases per 100,000 person years. These strategies would also result in significant reductions of pertussis costs (between -77% and -80% including additional vaccination costs. The cocoon strategy complemented by a single booster dose is the most cost-effective one, whereas the decennial adult vaccination is slightly more effective in the long run. CONCLUSIONS: By providing a high level of disease control, the implementation of an adult vaccination program against pertussis appears to be highly cost-effective and often cost-saving.
Belashov, Vasily
We study numerically the interaction of the vortex structures in the continuum, and, specifically, in fluids and plasmas in two-dimensional approximation, when the Euler-type equations are applicable, namely: begin{center} e_{i}d_{t}x_{i}=d_{y}_{i}H/B, e_{i}d_{t}y_{i}=-d_{x}_{i}H/B, d_{m}=d/dm; d_{t}rho+vnablarho=0, v= - [z, nablapsi]/B; Deltapsi - f = - phi where e_{i} is the strength (circulation) of discrete vortex or the charge per unit length of the filaments, phi is a z-component of vorticity zeta or charge density rho, and psi is a stream function or potential for the two-dimensional flow of inviscid fluid and guiding-centre plasma, respectively, and H is a Hamiltonian. Note, that in the continuum (fluid) model B=1 in the Hamiltonian eqs. Function f=0 for the continuum or quasi-particles (filaments) with Coulomb interaction models, and f=k(2) psi for a screened Coulomb interaction model. We consider here only case f=0, and generalization of our approximation for f=k(2) psi is rather trivial. For numerical simulation we used the contour dynamics method, to some extent modified. We fulfilled a number of the series of numerical simulations for study of two-vortex inter-action, the interaction in the N-vortex systems, including interaction between the vortex structures and the dust particles, and also interaction of two three-dimensional plane-rotating vortex structures within the framework of many-layer model of medium, in dependence on some parameters: initial distance between vortices, value and sign of their vorticities, and spatial configuration of the vortex system. The results obtained showed that for all cases in dependence on initial conditions two regimes of the interaction can be observed, namely: weak interaction with quasi-stationary evolution and active interaction with the "phase intermixing", when the evolution can lead to formation of complex forms of vorticity regions. The theoretical explanation of the effects, which we observed, is given on
Explosion of a collapsing Bose-Einstein condensate
Duine, R.A.; Stoof, H.T.C.
2001-01-01
We show that elastic collisions between atoms in a Bose-Einstein condensate with attractive interactions can lead to an explosion that ejects a large fraction of the collapsing condensate. We study variationally the dynamics of this explosion and find excellent agreement with recent experiments on
Explosion of a Collapsing Bose-Einstein Condensate
Duine, R.A.; Stoof, H.T.C.
2000-01-01
we show that elastic collisions between atoms in an Bose-Einstein condensate with attractive interactions lead to an explosion that ejects a large fraction of the collapsing condensate. We study variationally the dynamics of thes explosion and find excellent agreement with recent experiments on
Directory of Open Access Journals (Sweden)
Holger Cartarius
2013-01-01
Full Text Available We investigate the Gross-Pitaevskii equation for a Bose-Einstein condensate in a PT symmetric double-well potential by means of the time-dependent variational principle and numerically exact solutions. A one-dimensional and a fully three-dimensional setup are used. Stationary states are determined and the propagation of wave function is investigated using the time-dependent Gross-Pitaevskii equation. Due to the nonlinearity of the Gross-Pitaevskii equation the potential dependson the wave function and its solutions decide whether or not the Hamiltonian itself is PT symmetric. Stationary solutions with real energy eigenvalues fulfilling exact PT symmetry are found as well as PT broken eigenstates with complex energies. The latter describe decaying or growing probability amplitudes and are not true stationary solutions of the time-dependent Gross-Pitaevskii equation. However, they still provide qualitative information about the time evolution of the wave functions.
International Nuclear Information System (INIS)
Iwami, Hiroshi.
1981-01-01
Purpose: To control the dissolved oxygen concentration in water of a condensate feeding system to a desired level. Constitution: Coolant is fed to a nuclear reactor through a route from the steam exit of the reactor and by way of turbine, turbine condensator, condensate pump, condensate desalinator, feedwater heater and feed pump. Steam extraction lines are branched from the turbines, and pipeways are further branched from the steam extraction lines for feeding steam by way of extraction steam injection valves to steam-water mixers disposed on the upstream of the feedwater heater. On the downstream of the feedwater heater, is provided a dissolved oxygen concentration meter, the indication value of which controls the opening degree of the steam injection valves which, in turn, controls the opening degree of the steam feed valves for the feedwater heater to adjust the amount for the injection steams. Accordingly, the dissolved oxygen concentration in the water of the condensate feeding system can be controlled by the inclusion of steams with high dissolved oxygen concentration into the feedwater system from the turbine steam extraction lines by way of the mixers. (Furukawa, Y.)
Evaporation and condensation at a liquid surface. II. Methanol
Matsumoto, Mitsuhiro; Yasuoka, Kenji; Kataoka, Yosuke
1994-11-01
The rates of evaporation and condensation of methanol under the vapor-liquid equilibrium condition at the temperature of 300 and 350 K are investigated with a molecular dynamics computer simulation. Compared with the argon system (reported in part I), the ratio of self-reflection is similar (˜10%), but the ratio of molecule exchange is several times larger than the argon, which suggests that the conventional assumption of condensation as a unimolecular process completely fails for associating fluids. The resulting total condensation coefficient is 20%-25%, and has a quantitative agreement with a recent experiment. The temperature dependence of the evaporation-condensation behavior is not significant.
Inflation induced by Gravitino Condensation in Supergravity
Ellis, John
2013-01-01
We discuss the emergence of an inflationary phase in supergravity with the super-Higgs effect due to dynamical spontaneous breaking of supersymmetry, in which the role of the inflaton is played by the gravitino condensate. Realistic models compatible with the Planck satellite CMB data are found in conformal supergravity scenarios with dynamical gravitino masses that are small compared to the Planck mass, as could be induced by a non-trivial vacuum expectation value of the dilaton superfield of appropriate magnitude.
Iliev, Oleg P.
2013-05-15
Paper production is a problem with significant importance for society; it is also a challenging topic for scientific investigation. This study is concerned with the simulation of the pressing section of a paper machine. A two-dimensional model is developed to account for the water flow within the pressing zone. A Richards-type equation is used to describe the flow in the unsaturated zone. The dynamic capillary pressure-saturation relation is adopted for the paper production process. The mathematical model accounts for the coexistence of saturated and unsaturated zones in a multilayer computational domain. The discretization is performed by the MPFA-O method. Numerical experiments are carried out for parameters that are typical of the production process. The static and dynamic capillary pressure-saturation relations are tested to evaluate the influence of the dynamic capillary effect. © 2013 Springer Science+Business Media Dordrecht.
Directory of Open Access Journals (Sweden)
Poulomi Ray
Full Text Available Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF, Bone Morphogenetic Protein (BMP and Transforming Growth Factor beta (TGF-β signaling pathways. Rho Kinase (ROCK-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis.
Ray, Poulomi; Chapman, Susan C.
2015-01-01
Skeletal condensation occurs when specified mesenchyme cells self-organize over several days to form a distinctive cartilage template. Here, we determine how and when specified mesenchyme cells integrate mechanical and molecular information from their environment, forming cartilage condensations in the pharyngeal arches of chick embryos. By disrupting cytoskeletal reorganization, we demonstrate that dynamic cell shape changes drive condensation and modulate the response of the condensing cells to Fibroblast Growth Factor (FGF), Bone Morphogenetic Protein (BMP) and Transforming Growth Factor beta (TGF-β) signaling pathways. Rho Kinase (ROCK)-driven actomyosin contractions and Myosin II-generated differential cell cortex tension regulate these cell shape changes. Disruption of the condensation process inhibits the differentiation of the mesenchyme cells into chondrocytes, demonstrating that condensation regulates the fate of the mesenchyme cells. We also find that dorsal and ventral condensations undergo distinct cell shape changes. BMP signaling is instructive for dorsal condensation-specific cell shape changes. Moreover, condensations exhibit ventral characteristics in the absence of BMP signaling, suggesting that in the pharyngeal arches ventral morphology is the ground pattern. Overall, this study characterizes the interplay between cytoskeletal dynamics and molecular signaling in a self-organizing system during tissue morphogenesis. PMID:26237312
Suppressing Ice Nucleation of Supercooled Condensate with Biphilic Topography
Hou, Youmin; Yu, Miao; Shang, Yuhe; Zhou, Peng; Song, Ruyuan; Xu, Xiaonan; Chen, Xuemei; Wang, Zuankai; Yao, Shuhuai
2018-02-01
Preventing or minimizing ice formation in supercooled water is of prominent importance in many infrastructures, transportation, and cooling systems. The overall phase change heat transfer on icephobic surfaces, in general, is intentionally sacrificed to suppress the nucleation of water and ice. However, in a condensation frosting process, inhibiting freezing without compromising the water condensation has been an unsolved challenge. Here we show that this conflict between anti-icing and efficient condensation cooling can be resolved by utilizing biphilic topography with patterned high-contrast wettability. By creating a varying interfacial thermal barrier underneath the supercooled condensate, the biphilic structures tune the nucleation rates of water and ice in the sequential condensation-to-freezing process. Our experimental and theoretical investigation of condensate freezing dynamics further unravels the correlation between the onset of droplet freezing and its characteristic radius, offering a new insight for controlling the multiphase transitions among vapor, water, and ice in supercooled conditions.
Douté, Sylvain; Lopes, Rosaly; Kamp, Lucas W.; Carlson, Robert; Schmitt, Bernard; Galileo NIMS Team
2002-08-01
We analyze a series of spectral image cubes acquired by the Galileo Near Infrared Mapping Spectrometer (NIMS) over the Prometheus region of Io. We use SO 2 frost, a volatile compound ubiquitous on the surface, as a tracer to understand various thermodynamic and volcanic processes acting in this equatorial region. Here we develop a new method to derive, from the 12-wavelength NIMS products, the distribution and physical properties of solid SO 2. This method is based on the inversion of a bidirectional reflectance model on two observed spectral ratios sensitive to (1) the areal abundance of SO 2 and (2) its mean grain size. As a result, reliable and consistent maps of SO 2 abundance and granularity are obtained which can be correlated to distinguish four different physical units. The distribution of these SO 2 units indicates zones of condensation, metamorphism, and sublimation linked with the thermodynamic and volcanic processes of interest. Our maps depict equatorial plains undisturbed by any kind of vigorous volcanic activity over 35-40% of their surface. Elsewhere, 10-20% of the equatorial plains display abnormally low frost coverage which may imply the recent presence of positive thermal anomalies with temperatures in the range 110-200 K. Hot-spots such as Prometheus, Culann, Surya, and Tupan (to mention the most persistent) emit a great variety of gases, some of which will condense at Io's surface near their source regions. Associated fields of freshly condensed SO 2 are easily observed, and deposits of more refractory compounds with higher (e.g., S 8) or lower (e.g., NaCl) molecular weight must also be present (although their exact nature is unknown). Three different mechanisms of emission are proposed for the volatile compounds and supported by the distribution maps. These are (a) the interaction between flowing lava and preexisting volatile deposits on the surface, (b) direct degassing from the lava, an d (c) the eruption of a liquid aquifer from underground
Guillemin, Ernst A
2013-01-01
An eminent electrical engineer and authority on linear system theory presents this advanced treatise, which approaches the subject from the viewpoint of classical dynamics and covers Fourier methods. This volume will assist upper-level undergraduates and graduate students in moving from introductory courses toward an understanding of advanced network synthesis. 1963 edition.
Tanabe, M.; Wakui, H.; Sogabe, M.; Matsumoto, N.; Tanabe, Y.
2010-06-01
A combined multibody and finite element approach is given to solve the dynamic interaction of a Shinkansen train (high-speed train in Japan) and the railway structure including post-derailment during an earthquake effectively. The motion of the train is expressed in multibody dynamics. Efficient mechanical models to express interactions between wheel and track structure including post-derailment are given. Rail and track elements expressed in multibody dynamics and FEM are given to solve contact problems between wheel and long railway components effectively. The motion of a railway structure is modeled with various finite elements and rail and track elements. The computer program has been developed for the dynamic interaction analysis of a Shinkansen train and railway structure including post derailment during an earthquake. Numerical examples are demonstrated.
Kasinsky, H E; Ellis, S; Martens, G; Ausió, J
2014-12-01
During early-to-middle spermiogenesis in multicellular, internally fertilizing charalean green algae (Chara fibrosa, Chara vulgaris, Chara tomentosa, Nitella missouriensis), patterning of chromatin/nucleoplasm in developing spermatid nuclei changes from granules → fibers → contorted lamellae → condensed chromatin. Cytochemical, immunocytochemical, electrophoretic studies on C. vulgaris and C. tomentosa spermatids (Kwiatkowska, Poplonska) and amino acid analysis of protamines in Chara corallina sperm (Reynolds, Wolfe), indicate that more positively charged protamines replace histones directly during spermiogenesis, not indirectly through other intermediate transitional proteins as in internally fertilizing neogastropods and sharks with more ordered spermatid lamellae. We hypothesize that such lamellar-mediated patterning is due to liquid-liquid phase separation by spinodal decomposition. This is a spontaneous thermodynamic process that involves diffusive instability of a lamellar chromatin network, a dominant pattern repeat distance and bicontinuity of chromatin/nucleoplasm phases. C. vulgaris sperm show contorted lamellae in the posterior region, whereas C. corallina sperm display contorted peripheral lamellae and interior fibrils. Among internally fertilizing liverworts, which may have evolved from Zygnematales, mid-spermatid nuclei lack lamellae. Instead they display self-coiled chromatin rods in Blasia pusilla, contain short chromatin tubules in Haplomitrium hookeri resembling those in internally fertilizing mosses and a hornwort and indirectly replace histones with protamines in Marchantia polymorpha. Copyright © 2014. Published by Elsevier Ltd.
International Nuclear Information System (INIS)
Anon.
1985-01-01
The condensed matter physics research in the Physics Department of Risoe National Laboratory is predominantly experimental utilising diffraction of neutrons and x-rays. The research topics range from studies of structure, excitations and phase transitions in model systems to studies of ion transport, texture and recrystallization kinetics with a more applied nature. (author)
Modular invariant gaugino condensation
Energy Technology Data Exchange (ETDEWEB)
Gaillard, M.K.
1991-05-09
The construction of effective supergravity lagrangians for gaugino condensation is reviewed and recent results are presented that are consistent with modular invariance and yield a positive definite potential of the noscale type. Possible implications for phenomenology are briefly discussed. 29 refs.
Indian Academy of Sciences (India)
have quoted, London noted that at the density of liquid helium, the temperature for Bose-Einstein condensation of an ideal gas would be about three degrees above absolute zero.4 Liquid helium shows new properties below 2.1 degrees Kelvin [3]. London boldly suggested that these new properties were a consequence of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 12. Bose-Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. Volume 10 Issue 12 December 2005 pp 142-147. Fulltext. Click here to view fulltext PDF. Permanent link:
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 4. Bose–Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. General Article Volume 5 Issue 4 April 2000 pp 46-51. Fulltext. Click here to view fulltext PDF. Permanent link:
Indian Academy of Sciences (India)
Bose-Einstein Condensation. Vasant Natarajan is at the. Department of Physics,. Indian Institute of. Science. His current research involves trapping of atoms to carry out high precision tests of fundamental physics. He has earlier worked on high precision mass spectrom- etry and on the focussing of atomic beams by laser.
International Nuclear Information System (INIS)
1990-01-01
This is a summary of condensed matter physics in Brazil. It discusses as well, the perspectives and financing evolved in this research area for the next decade. It is specially concerned with semiconductors, magnetic materials, superconductivity, polymers, glasses, crystals ceramics, statistical physics, magnetic resonance and Moessbauer spectroscopy. (A.C.A.S.)
Indian Academy of Sciences (India)
Electrons in Condensed Matter. T V Ramakrishnan. Introduction. A hundred years ago, J J Thomson tore light negatively charged particles out of many different kinds of atoms by subjecting them to strong electric fields in discharge tubes. He showed that the same particle (with identical charge e and charge to mass ratio ...
DEFF Research Database (Denmark)
Johansen, Per; Rømer, Daniel; Andersen, Torben Ole
2014-01-01
The increasing interest in hydraulic transmissions in wind and wave energy applications has created an incentive for the development of high efficiency fluid power machinery. Modeling and analysis of fluid power machinery loss mechanisms are necessary in order to accommodate this demand. At present...... fully coupled thermo-elastic models has been used to simulate and study loss mechanisms in various tribological interfaces. Consequently, a reasonable focus of further development is to couple the interface models and the rigid body mechanics of fluid power machinery. The focus of the current paper...... is a multibody dynamics model of a radial piston fluid power motor, which connects the rigid bodies through models of the transient hydrodynamic lubrication pressure in the joint clearance. A finite volume approach is used to model the pressure dynamics of the fluid film lubrication. The model structure...
Blower, Sally; Go, Myong-Hyun
2011-01-01
Abstract Mathematical models are useful tools for understanding and predicting epidemics. A recent innovative modeling study by Stehle and colleagues addressed the issue of how complex models need to be to ensure accuracy. The authors collected data on face-to-face contacts during a two-day conference. They then constructed a series of dynamic social contact networks, each of which was used to model an epidemic generated by a fast-spreading airborne pathogen. Intriguingly, Stehle and colleagu...
Modelling of film condensation in presence of non condensable gases
International Nuclear Information System (INIS)
Genevieve Geffraye; Dominique Bestion; Vladimir Kalitvianski
2005-01-01
Full text of publication follows: This paper presents recent developments in the modelling of the condensation due to heat removal from a wall with a possible presence of hydrogen, nitrogen, or air. This work is mainly concerned with nuclear reactor safety with particular reference to situations related to new reactor design, cold shutdown state and severe accident analysis. Film condensation of steam in presence of nitrogen and helium in a tube has been investigated in the COTURNE experiment in a rather large range of parameters, pressure (from 0.1 to 7 Mpa), heat flux (0.1 to 6 W/cm 2 ), mass fraction of noncondensable gas (0 to 1) and also in presence of superheated steam. The experiment represents a Steam Generator tube of a Pressurised Water Reactor and can simulate both co-current or countercurrent flow of steam and water.The models are implemented in the CATHARE code used for nuclear reactor thermal-hydraulics. The code uses two mass balance equations for liquid and gas, two momentum balance equations for liquid and gas and two energy balance equations for liquid and gas. Additional mass transport equations can be added for each non condensable gas. Heat transfers from wall to liquid film, from liquid to interface and gas to interface are modelled. The liquid film heat transfer coefficient is first investigated in pure saturated steam conditions in the pressure range from 0.1 to 7 Mpa. The CATHARE film condensation model in pure steam conditions is derived from Chen's correlation. Chen proposes a general correlation for the film condensation, covering the wavy-laminar and the turbulent film regimes and taking into account the interfacial friction effect. A large data base of laminar film regime was used including COTURNE data other available data found in the literature. The analysis of these data base suggests an influence of the liquid Reynolds number, according to the Nusselt theory, and also of the Eoetvoes number, with surface tension effects. A
Directory of Open Access Journals (Sweden)
Faezeh sadat Tabatabai Amiri
2012-10-01
Full Text Available The purpose of this research was to make exam the indexing and ranking of XML content objects containing Dublin Core and MARC 21 metadata elements in dynamic online information environments by general search engines and comparing them together in a comparative-analytical approach. 100 XML content objects in two groups were analyzed: those with DCXML elements and those with MARCXML elements were published in website http://www.marcdcmi.ir. from late Mordad 1388 till Khordad 1389. Then the website was introduced to Google and Yahoo search engines. Google search engine was able to retrieve fully all the content objects during the study period through their Dublin Core and MARC 21 metadata elements; Yahoo search engine, however, did not respond at all. The indexing of metadata elements embedded in content objects in dynamic online information environments and different between indexing and ranking of them were examined. Findings showed all Dublin Core and MARC 21 metadata elements by Google search engine were indexed. And there was not observed difference between indexing and ranking DCXML and MARCXML metadata elements in dynamic online information environments by Google search engine.
DEFF Research Database (Denmark)
Róg, Tomasz; Orłowski, Adam; Llorente, Alicia
2016-01-01
In this Data in Brief article we provide a data package of GROMACS input files for atomistic molecular dynamics simulations of multicomponent, asymmetric lipid bilayers using the OPLS-AA force field. These data include 14 model bilayers composed of 8 different lipid molecules. The lipids present......, and cholesterol, while the extracellular leaflet is composed of SM, PC and cholesterol discussed in Van Meer et al. (2008) [2]. The provided data include lipids' topologies, equilibrated structures of asymmetric bilayers, all force field parameters, and input files with parameters describing simulation conditions...
Johnson, T H; Yuan, Y; Bao, W; Clark, S R; Foot, C; Jaksch, D
2016-06-17
We investigate cold bosonic impurity atoms trapped in a vortex lattice formed by condensed bosons of another species. We describe the dynamics of the impurities by a bosonic Hubbard model containing occupation-dependent parameters to capture the effects of strong impurity-impurity interactions. These include both a repulsive direct interaction and an attractive effective interaction mediated by the Bose-Einstein condensate. The occupation dependence of these two competing interactions drastically affects the Hubbard model phase diagram, including causing the disappearance of some Mott lobes.
Brinkmann, Ralf Peter
2015-12-01
The electric field in radio-frequency driven capacitively coupled plasmas (RF-CCP) is studied, taking thermal (finite electron temperature) and dynamic (finite electron mass) effects into account. Two dimensionless numbers are introduced, the ratios ε ={λ\\text{D}}/l of the electron Debye length {λ\\text{D}} to the minimum plasma gradient length l (typically the sheath thickness) and η ={ω\\text{RF}}/{ω\\text{pe}} of the RF frequency {ω\\text{RF}} to the electron plasma frequency {ω\\text{pe}} . Assuming both numbers small but finite, an asymptotic expansion of an electron fluid model is carried out up to quadratic order inclusively. An expression for the electric field is obtained which yields (i) the space charge field in the sheath, (ii) the generalized Ohmic and ambipolar field in the plasma, and (iii) a smooth interpolation for the transition in between. The new expression is a direct generalization of the Advanced Algebraic Approximation (AAA) proposed by the same author (2009 J. Phys. D: Appl. Phys. 42 194009), which can be recovered for η \\to 0 , and of the established Step Model (SM) by Godyak (1976 Sov. J. Plasma Phys. 2 78), which corresponds to the simultaneous limits η \\to 0 , ε \\to 0 . A comparison of the hereby proposed Smooth Step Model (SSM) with a numerical solution of the full dynamic problem proves very satisfactory.
Energy Technology Data Exchange (ETDEWEB)
Blaizot, Jean-Paul [Institut de Physique Théorique, CNRS/URA 2306, CEA Saclay, F-91191 Gif-sur-Yvette (France); Liao, Jinfeng [Physics Dept. and CEEM, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); McLerran, Larry [Physics Dept., Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Physics Department, China Central Normal University, Wuhan (China)
2014-11-15
To understand the evolution of a dense system of gluons, such as those produced in the early stages of ultra-relativistic heavy ion collisions, is an important and challenging problem. We describe the approach to thermal equilibrium using the small angle approximation for gluon scattering in a Boltzmann equation that includes the effects of Bose statistics. The role of Bose statistical factors in amplifying the rapid growth of the population of the soft modes is essential. With these factors properly taken into account, one finds that elastic scattering alone provides an efficient mechanism for populating soft modes, and in fact leads to rapid infrared local thermalization. Furthermore, recent developments suggest that high initial overpopulation plays a key role and may lead to dynamical Bose–Einstein condensation. The kinetics of condensation is an interesting problem in itself. By solving the transport equation for initial conditions with a large enough initial phase-space density the equilibrium state contains a Bose condensate, and we present numerical evidence that such over-occupied systems reach the onset of Bose–Einstein condensation in a finite time. It is also found that the approach to condensation is characterized by a scaling behavior. Finally we discuss a number of extensions of the present study.
International Nuclear Information System (INIS)
Blaizot, Jean-Paul; Liao, Jinfeng; McLerran, Larry
2014-01-01
To understand the evolution of a dense system of gluons, such as those produced in the early stages of ultra-relativistic heavy ion collisions, is an important and challenging problem. We describe the approach to thermal equilibrium using the small angle approximation for gluon scattering in a Boltzmann equation that includes the effects of Bose statistics. The role of Bose statistical factors in amplifying the rapid growth of the population of the soft modes is essential. With these factors properly taken into account, one finds that elastic scattering alone provides an efficient mechanism for populating soft modes, and in fact leads to rapid infrared local thermalization. Furthermore, recent developments suggest that high initial overpopulation plays a key role and may lead to dynamical Bose–Einstein condensation. The kinetics of condensation is an interesting problem in itself. By solving the transport equation for initial conditions with a large enough initial phase-space density the equilibrium state contains a Bose condensate, and we present numerical evidence that such over-occupied systems reach the onset of Bose–Einstein condensation in a finite time. It is also found that the approach to condensation is characterized by a scaling behavior. Finally we discuss a number of extensions of the present study
Influence of non condensable gases on condenser performance. Bibliographical study
International Nuclear Information System (INIS)
Phong, Vinh
1970-09-01
The author proposes a synthesis of a bibliographical study on condenser performance, and more particularly on the influence of non-condensables on these performance. He distinguishes experimental studies, and analytical or theoretical studies. As far as experimental studies are concerned, he discusses various factors: influence of the rate of non condensables and of scan rate, influence of condenser geometry, influence of the exchanged heat flow, influence of the operational pressure, empirical correlations. As far as analytical studies on the influence of non-condensables are concerned, the author discusses and comments diffusion laws, and some specific studies [fr
Chemical equilibrium of ablation materials including condensed species
Stroud, C. W.; Brinkley, K. L.
1975-01-01
Equilibrium is determined by finding chemical composition with minimum free energy. Method of steepest descent is applied to quadratic representation of free-energy surface. Solution is initiated by selecting arbitrary set of mole fractions, from which point on free-energy surface is computed.
Research Status of Evaporative Condenser
Wang, Feifei; Yang, Yongan
2018-02-01
Reducing energy consumption, saving water resources, recycling cool water are main directions of China’s development. Evaporative condenser using latent heat reduces water resources waste, with energy-saving advantages. This paper reviews the research status of evaporative condenser at home and abroad, and introduces the principle, classification, various influencing factors of evaporative condenser, and puts forward the future research direction.
Ab Initio Molecular Dynamics Study of the Very Short O-H···O Hydrogen Bonds in the Condensed Phases.
Durlak, Piotr; Latajka, Zdzisław
2013-01-08
In this paper are presented the results of theoretical studies of the structure and proton motion in very short O···O intramolecular hydrogen bonds in two molecular crystals. A comparison was conducted between 3-cyano-2,4-pentanedione (I) and 4-cyano-2,2,6,6-tetramethyl-3,5-heptanedione (II) in the solid state. The dynamics of proton motion in the O-H···O hydrogen bond were investigated in he NVT ensemble at 298 and 50 K, respectively, for crystals I and II using Car-Parrinello and path integral molecular dynamics. Very large delocalization of the bridging proton was noted especially in the path integral simulation where quantum effects are taken into account. The infrared spectrum was calculated, and a comparative vibrational analysis was performed. CPMD vibrational results appear to be in qualitative agreement with the experimental ones.
Directory of Open Access Journals (Sweden)
E.C. Biscaia Junior
2001-06-01
Full Text Available A dynamic kinetic-diffusive model for the extraction of metallic ions from aqueous liquors using liquid surfactant membranes is proposed. The model incorporates undesirable intrinsic phenomena such as swelling and breakage of the emulsion globules that have to be controlled during process operation. These phenomena change the spatial location of the chemical reaction during the course of extraction, resulting in a transient moving boundary problem. The orthogonal collocation method was used to transform the partial differential equations into an ordinary differential equation set that was solved by an implicit numerical routine. The model was found to be numerically stable and reliable in predicting the behaviour of zinc extraction with acidic extractant for long residence times.
Recovery of condensate water quality in power generator's surface condenser
Kurniawan, Lilik Adib
2017-03-01
In PT Badak NGL Plant, steam turbines are used to drive major power generators, compressors, and pumps. Steam exiting the turbines is condensed in surface condensers to be returned to boilers. Therefore, surface condenser performance and quality of condensate water are very important. One of the recent problem was caused by the leak of a surface condenser of Steam Turbine Power Generator. Thesteam turbine was overhauled, leaving the surface condenser idle and exposed to air for more than 1.5 years. Sea water ingress due to tube leaks worsens the corrosionof the condenser shell. The combination of mineral scale and corrosion product resulting high conductivity condensate at outlet condenser when we restarted up, beyond the acceptable limit. After assessing several options, chemical cleaning was the best way to overcome the problem according to condenser configuration. An 8 hour circulation of 5%wt citric acid had succeed reducing water conductivity from 50 μmhos/cm to below 5 μmhos/cm. The condensate water, then meets the required quality, i.e. pH 8.3 - 9.0; conductivity ≤ 5 μmhos/cm, therefore the power generator can be operated normally without any concern until now.
Asymmetric condensed dark matter
Energy Technology Data Exchange (ETDEWEB)
Aguirre, Anthony; Diez-Tejedor, Alberto, E-mail: aguirre@scipp.ucsc.edu, E-mail: alberto.diez@fisica.ugto.mx [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA, 95064 (United States)
2016-04-01
We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.
Quantum monodromy in trapped Bose condensates
International Nuclear Information System (INIS)
Waalkens, H.
2002-01-01
Bose-Einstein condensation of ultra cold atoms is typically realized in magnetic traps which effectively lead to an axially symmetric harmonic potential. This letter shows that the spectrum of collective vibrational modes of a repulsive condensate in a prolate potential displays a defect known as quantum monodromy. The monodromy is analysed on the basis of the dynamics of quasiparticles. In terms of the quasiparticles the regime of collective modes or the so-called hydrodynamic regime is characterized through kinetic energies much smaller than the chemical potential. In this limit the classical dynamics of the quasiparticles is integrable. The monodromy is quantitatively described by a monodromy matrix that is calculated from classical actions. (authors)
Development status of condensed cluster fusion theory
International Nuclear Information System (INIS)
Takahashi, Akito
2015-01-01
The condensed cluster fusion theory has been developed since 1989, under the view that dynamic ordering processes of confined transient clusters of D(H)-particles in catalytic surface sites, vacancies and global mesoscopic potential well of metal nanoparticles may induce simultaneous multi-body fusion reactions. One thorough answer is obtained for the condensation motion of clusters under platonic symmetry like 4D(H)/TSC, 6D(H)/RDC and 8D(H)/RDC and their fusion reaction rates. Theoretical analysis for initial dynamic clustering process on/in catalytic sites is still speculative and under searching a technique to combine the electron density functional method and the QM Langevin method. (author)
Bouncing cosmologies from quantum gravity condensates
Oriti, Daniele; Sindoni, Lorenzo; Wilson-Ewing, Edward
2017-02-01
We show how the large-scale cosmological dynamics can be obtained from the hydrodynamics of isotropic group field theory condensate states in the Gross-Pitaevskii approximation. The correct Friedmann equations are recovered in the classical limit for some choices of the parameters in the action for the group field theory, and quantum gravity corrections arise in the high-curvature regime causing a bounce which generically resolves the big-bang and big-crunch singularities.
Condensation of steam in horizontal pipes: model development and validation
International Nuclear Information System (INIS)
Szijarto, R.
2015-01-01
This thesis submitted to the Swiss Federal Institute of Technology ETH in Zurich presents the development and validation of a model for the condensation of steam in horizontal pipes. Condensation models were introduced and developed particularly for the application in the emergency cooling system of a Gen-III+ boiling water reactor. Such an emergency cooling system consists of slightly inclined horizontal pipes, which are immersed in a cold water tank. The pipes are connected to the reactor pressure vessel. They are responsible for a fast depressurization of the reactor core in the case of accident. Condensation in horizontal pipes was investigated with both one-dimensional system codes (RELAP5) and three-dimensional computational fluid dynamics software (ANSYS FLUENT). The performance of the RELAP5 code was not sufficient for transient condensation processes. Therefore, a mechanistic model was developed and implemented. Four models were tested on the LAOKOON facility, which analysed direct contact condensation in a horizontal duct
Yang, Bin; Lai, Wen-Sheng
2009-06-01
The relative stability of fcc and bcc solid solutions and amorphous phase with different compositions in the Cu-Al system is studied by molecular dynamics simulations with n-body potentials. For Cu1-xAlx alloys, the calculations show that the fcc solid solution has the lowest energies in the composition region with x 0.72, while the bee solid solution has the lowest energies in the central composition range, in agreement with the ball-milling experiments that a single bcc solid solution with 0.30 < x < 0.70 is obtained. The evolution of structures in solid solutions and amorphous phase is studied by the coordination number (CN) and bond-length analysis so as to unveil the underlying physics. It is found that the energy sequence among three phases is determined by the competition in energy change originating from the bond length and CNs (or the number of bonds).
Wickramasinghe, Gammadde Hewa Ishan Maduka; Rathnayake, Pilimathalawe Panditharathna Attanayake Mudiyanselage Samith Indika; Chandrasekharan, Naduviladath Vishvanath; Weerasinghe, Mahindagoda Siril Samantha; Wijesundera, Ravindra Lakshman Chundananda; Wijesundera, Wijepurage Sandhya Sulochana
2017-06-21
between the amino acid residues of BGLI and cellobiose are mainly involved in the integrity of enzyme-substrate association. The BGLI activity was remarkably higher in the genomic DNA clone compared to the cDNA clone. Cellobiose was successfully fermented into ethanol by the recombinant S.cerevisiae genomic DNA clone. It has the potential to be used in the industrial production of ethanol as it is capable of simultaneous saccharification and fermentation of cellobiose. Homology modeling, docking studies and molecular dynamics simulation studies will provide a realistic model for further studies in the modification of active site residues which could be followed by mutation studies to improve the catalytic action of BGLI.
International Nuclear Information System (INIS)
Sapoval, B.
1988-01-01
The 1988 progress report of the laboratory of the Condensed Matter Physics (Polytechnic School, France), is presented. The Laboratory activities are related to the physics of semiconductors and disordered phases. The electrical and optical properties of the semiconductors, mixed conductor, superionic conductors and ceramics, are studied. Moreover, the interfaces of those systems and the sol-gel inorganic polymerization phenomena, are investigated. The most important results obtained, concern the following investigations: the electrochemical field effect transistor, the cathodoluminescence, the low energy secondary electrons emission, the fluctuations of a two-dimensional diffused junction and the aerogels [fr
Monastyrsky, M I
2006-01-01
This book reports new results in condensed matter physics for which topological methods and ideas are important. It considers, on the one hand, recently discovered systems such as carbon nanocrystals and, on the other hand, new topological methods used to describe more traditional systems such as the Fermi surfaces of normal metals, liquid crystals and quasicrystals. The authors of the book are renowned specialists in their fields and present the results of ongoing research, some of it obtained only very recently and not yet published in monograph form.
Steam condensation modelling in aerosol codes
International Nuclear Information System (INIS)
Dunbar, I.H.
1986-01-01
The principal subject of this study is the modelling of the condensation of steam into and evaporation of water from aerosol particles. These processes introduce a new type of term into the equation for the development of the aerosol particle size distribution. This new term faces the code developer with three major problems: the physical modelling of the condensation/evaporation process, the discretisation of the new term and the separate accounting for the masses of the water and of the other components. This study has considered four codes which model the condensation of steam into and its evaporation from aerosol particles: AEROSYM-M (UK), AEROSOLS/B1 (France), NAUA (Federal Republic of Germany) and CONTAIN (USA). The modelling in the codes has been addressed under three headings. These are the physical modelling of condensation, the mathematics of the discretisation of the equations, and the methods for modelling the separate behaviour of different chemical components of the aerosol. The codes are least advanced in area of solute effect modelling. At present only AEROSOLS/B1 includes the effect. The effect is greater for more concentrated solutions. Codes without the effect will be more in error (underestimating the total airborne mass) the less condensation they predict. Data are needed on the water vapour pressure above concentrated solutions of the substances of interest (especially CsOH and CsI) if the extent to which aerosols retain water under superheated conditions is to be modelled. 15 refs
Spermine Condenses DNA, but Not RNA Duplexes
Energy Technology Data Exchange (ETDEWEB)
Katz, Andrea M.; Tolokh, Igor S.; Pabit, Suzette A.; Baker, Nathan; Onufriev, Alexey V.; Pollack, Lois
2017-01-01
Interactions between the polyamine spermine and nucleic acids drive important cellular processes. Spermine condenses DNA, and some RNAs such as poly(rA):poly(rU). A large fraction of the spermine present in cells is bound to RNA, but apparently does not condense it. Here, we study the effect of spermine binding to short duplex RNA and DNA and compare our findings with predictions of molecular dynamics simulations. When small numbers of spermine are introduced, RNA with a designed sequence, containing a mixture of 14 GC pairs and 11 AU pairs, resists condensation relative to DNA of an equivalent sequence or to 25 base pair poly(rA):poly(rU) RNA. Comparison of wide-angle x-ray scattering profiles with simulation suggests that spermine is sequestered deep within the major groove of mixed sequence RNA, preventing condensation by limiting opportunities to bridge to other molecules as well as stabilizing the RNA by locking it into a particular conformation. In contrast, for DNA, simulations suggest that spermine binds external to the duplex, offering opportunities for intermolecular interaction. The goal of this study is to explain how RNA can remain soluble, and available for interaction with other molecules in the cell, despite the presence of spermine at concentrations high enough to precipitate DNA.
Energy Technology Data Exchange (ETDEWEB)
Macedo Muth, Javier; Sandoval Pena, Ramon [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)
1988-12-31
This article shows a non-lineal mathematical model for the condensate, and feed water systems and for feed water heater drains at the Laguna Verde Nuclear Power Station for its simulation in real time. The model allows the calculation of flows and pressures in all the piping system and equipment that integrate the systems. It was obtained by using the force unbalance in the fluid concept and is capable of reproducing its dynamic behavior through variations induced by the different operation modes and more common failures. The final model objective is to form part of the Laguna Verde simulator that will be used for operator training of this Nuclear Power Plant. [Espanol] En este articulo se muestra un modelo matematico no lineal de los sistemas de condensado, agua de alimentacion y drenes de calentadores de la central nuclear de Laguna Verde para su simulacion en tiempo real. El modelo permite calcular los flujos y las presiones en toda la red de tuberias y equipos que integran los sistemas. Se obtuvo utilizando el concepto de desbalance de fuerzas en el fluido, y es capaz de reproducir su comportamiento dinamico ante variaciones inducidas por los diversos modos de operacion y fallas mas comunes. El objetivo final del modelo es formar parte del simulador de Laguna Verde que se empleara para el adiestramiento de los operadores de dicha central nuclear.
Bose-Einstein condensation of atomic gases
International Nuclear Information System (INIS)
Anglin, J. R.; Ketterle, W.
2003-01-01
The early experiments on Bose-Einstein condensation in dilute atomic gases accomplished three longstanding goals. First, cooling of neutral atoms into their motional state, thus subjecting them to ultimate control, limited only by Heisenberg uncertainty relation. Second, creation of a coherent sample of atoms, in which all occupy the same quantum states, and the realization of atom lasers - devices that output coherent matter waves. And third, creation of gaseous quantum fluid, with properties that are different from the quantum liquids helium-3 and helium-4. The field of Bose-Einstein condensation of atomic gases has continued to progress rapidly, driven by the combination of new experimental techniques and theoretical advances. The family of quantum degenerate gases has grown, and now includes metastable and fermionic atoms. condensates have become an ultralow-temperature laboratory for atom optics, collisional physics and many-body physics, encompassing phonons, superfluidity, quantized vortices, Josephson junctions and quantum phase transitions. (author)
Condensed medium neutron-diffraction study in JINR
International Nuclear Information System (INIS)
Balagurov, A.M.; Natkanets, I.; Ostanevich, Yu.M.
1986-01-01
A brief review of development of neutron diffraction investigations into condensed media in JINR is given. Structural neutron diffraction and dynamics of condensed media are considered. Commissioning of the IBR-2 reactor allowed one to investigate segnetoelectric and segnetoelastic crystals, conduct first experiments on neutron diffraction, using a monocrystal of myoglobin muscle protein. Texture neutron diffraction method is being developed. Simultaneously with the start-up activities, development of methods for experiments on the neutron inelastic scattering has begun. Two different experimental problems were solved: elementary excitation spectrum investigation and search for Bose-condensate. The growth of the JINR science and technology potential is accompanied by a rapid expansion of international cooperation
Polariton Bose condensate in an open system: Ab initio approach
Elistratov, A. A.; Lozovik, Yu. E.
2018-01-01
In the framework of path-integral formalism and Keldysh technique for a nonequilibrium system we explore the kinetics of the polariton condensate in a quantum well embedded in an optical microcavity. We take into account pumping and leakage of excitons and photons. We make an ab initio derivation of the equations governing the dynamics of the condensates and reservoirs and show that the real open polariton system has a non-Markovian character at times comparable to the Rabi oscillation period.
Liquid oil production from shale gas condensate reservoirs
Energy Technology Data Exchange (ETDEWEB)
Sheng, James J.
2018-04-03
A process of producing liquid oil from shale gas condensate reservoirs and, more particularly, to increase liquid oil production by huff-n-puff in shale gas condensate reservoirs. The process includes performing a huff-n-puff gas injection mode and flowing the bottom-hole pressure lower than the dew point pressure.
Ferminoic physics in dipolariton condensates.
Su, Jung-Jung; Kim, Na Young; Yamamoto, Yoshihisa; Macdonald, Allan H
2014-03-21
An exciton polariton is an extremely light bosonic quasiparticle that is composed of an exciton and a photon. We report on a theoretical study of exciton-polariton condensation in a system with tunnel-coupled quantum wells. Because their excitons can carry an electric dipole moment, these systems have been referred to as dipolariton condensates. We use a fermionic mean-field theory that can address quantum well and other internal exciton degrees of freedom to describe the new physics present in dipolariton condensates. We find that the role of underlying fermonic degrees of freedom is enhanced and predict that metallic condensates can occur at high carrier densities.
Microgravity condensing heat exchanger
Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)
2011-01-01
A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.
Faraday waves in Bose-Einstein condensates
International Nuclear Information System (INIS)
Nicolin, Alexandru I.; Carretero-Gonzalez, R.; Kevrekidis, P. G.
2007-01-01
Motivated by recent experiments on Faraday waves in Bose-Einstein condensates we investigate both analytically and numerically the dynamics of cigar-shaped Bose-condensed gases subject to periodic modulation of the strength of the transverse confinement. We offer a fully analytical explanation of the observed parametric resonance, based on a Mathieu-type analysis of the non-polynomial Schroedinger equation. The theoretical prediction for the pattern periodicity versus the driving frequency is directly compared to the experimental data, yielding good qualitative and quantitative agreement between the two. These results are corroborated by direct numerical simulations of both the one-dimensional non-polynomial Schroedinger equation and of the fully three-dimensional Gross-Pitaevskii equation
Energy Technology Data Exchange (ETDEWEB)
Castleman, A.W. Jr.
1994-10-01
Chemical reactions that proceed following either a photophysical or ionizing event, are directly influenced by the mechanisms of energy transfer and dissipation away from the site of absorption. Neighboring solvent or solute molecules can affect this by collisional deactivation (removal of energy), through effects in which dissociating molecules are kept in relatively close proximity for comparatively long periods of time due to the presence of the solvent, and in other ways where the solvent influences the energetics of the reaction coordinate. Research on clusters offers promise of elucidating the molecular details of these processes. The studies have focused on providing critical information on problems in radiation biology through investigations of reactions of molecules which simulate functional groups in biological systems, as they proceed following the absorption of ionizing radiation. The overall objective of the program has been to undertake basic underpinning research that contributes to a quantification of the behavior of radionuclides and pollutants associated with advanced energy activities after these materials emanate from their source and are transferred through the environment to the biota and human receptor. Some of the studies have dealt with the interaction of electromagnetic radiation with matter yielding new data that finds value in assessing photoinduced transformation of pollutants including reactions which take place on aerosol particles, as well as those of species which become transformed into aerosols as a result of their chemical and physical interactions.
Benedetto, E; Borburgh, J; Carli, C; Martini, M; Forte, V
2014-01-01
The CERN PS Booster will be upgraded with an H- injection system. The chicanemagnets for the injection bump ramp-down in 5 ms and generate eddy currents in the inconel vacuum chamber which perturb the homogeneity of the magnetic field. The multipolar field components are extracted from 3D OPERA simulations and are included in the lattice model. The -beating correction is computed all along the ramp and complete tracking simulations including space-charge are performed to evaluate the impact of these perturbations and correction on beam dynamics.
Supersymmetry is afraid of condensates
Directory of Open Access Journals (Sweden)
G. Domokos
1983-01-01
Full Text Available Supersymmetry is never broken by pair condensates of chiral superfields: the supersymmetry breaking part of Green's functions satisfies an equation which always has an identically vanishing solution. Hence any phase containing pair condensates is unstable due to its positive vacuum energy.
Response of Bose-Einstein condensates to external perturbations at finite temperature
International Nuclear Information System (INIS)
Morgan, S.A.
2004-01-01
We present a theory of the linear response of a Bose-Einstein-condensed gas to external perturbations at finite temperature. The theory developed here is the basis of a recent quantitative explanation of the measurements of condensate excitations and decay rates made at JILA [D. S. Jin et al., Phys. Rev. Lett. 78, 764 (1997)]. The formalism is based on a dynamic, number-conserving, mean-field scheme and is valid in the collisionless limit of well-defined quasiparticles. The theory is gapless, consistent with the generalized Kohn theorem for the dipole modes, and includes the time-dependent normal and anomalous averages, Beliaev and Landau processes, and all relevant finite-size effects. The important physical process where the thermal cloud is driven directly by the external perturbation is explicitly included. This is required for consistency with the dipole modes and is also needed to explain the JILA observations
Lombardo, Giuseppe M.; Portalone, Gustavo; Colapietro, Marcello; Rescifina, Antonio; Punzo, Francesco
2011-05-01
The ability of caffeic acid to act as antioxidant against hyperoxo-radicals as well as its recently found therapeutic properties in the treatment of hepatocarcinoma, still make this compound, more than 20 years later the refinement of its crystal structure, object of study. It belongs to the vast family of humic substances, which play a key role in the biodegradation processes and easily form complexes with ions widely diffused in the environment. This class of compounds is therefore interesting for potential environmental chemistry applications concerning the possible complexation of heavy metals. Our study focused on the characterization of caffeic acid as a starting necessary step, which will be followed in the future by the application of our findings on the study of the properties of caffeate anion interaction with heavy metal ions. To reach this goal, we applied a low cost approach - in terms of computational time and resources - aimed at the achievement of a high resolution, robust and trustable structure using the X-ray single crystal data, recollected with a higher resolution, as touchstone for a detailed check. A comparison between the calculations carried out with density functional theory (DFT), Hartree-Fock (HF) method and post SCF second order Møller-Plesset perturbation method (MP2), at the 6-31G ** level of the theory, molecular mechanics (MM) and molecular dynamics (MD) was performed. As a consequence we explained on one hand the possible reasons for the pitfalls of the DFT approach and on the other the benefits of using a good and robust force field developed for condensed phases, as AMBER, with MM and MD. The reliability of the latter, highlighted by the overall agreement extended up to the anisotropic displacement parameters calculated by means of MD and the ones gathered by X-ray measurements, makes it very promising for the above-mentioned goals.
Lindblom, Erik; Press-Kristensen, Kåre; Vanrolleghem, Peter A; Mikkelsen, Peter S; Henze, Mogens
2009-07-01
The perspective of this work is to develop a model, which can be used to better understand and optimize wastewater treatment plants that are able to remove xenobiotic organic compounds (XOCs) in combination with removal of traditional pollutants. Results from dynamic experiments conducted with the endocrine disrupting XOC bisphenol-A (BPA) in an activated sludge process with real wastewater were used to hypothesize an ASM-based process model including aerobic growth of a specific BPA-degrading microorganism and sorption of BPA to sludge. A parameter estimation method was developed, which simultaneously utilizes steady-state background concentrations and dynamic step response data, as well as conceptual simplifications of the plant configuration. Validation results show that biodegradation of BPA is sensitive to operational conditions before and during the experiment and that the proposed model structure is capable of capturing important characteristics of the observed BPA removal, thus increasing the potential for generalizing knowledge obtained from plant specific experiments.
Róg, Tomasz; Orłowski, Adam; Llorente, Alicia; Skotland, Tore; Sylvänne, Tuulia; Kauhanen, Dimple; Ekroos, Kim; Sandvig, Kirsten; Vattulainen, Ilpo
2016-06-01
In this Data in Brief article we provide a data package of GROMACS input files for atomistic molecular dynamics simulations of multicomponent, asymmetric lipid bilayers using the OPLS-AA force field. These data include 14 model bilayers composed of 8 different lipid molecules. The lipids present in these models are: cholesterol (CHOL), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine (POPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylethanolamine (POPE), 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidyl-ethanolamine (SOPE), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (POPS), 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidylserine (SOPS), N-palmitoyl-D-erythro-sphingosyl-phosphatidylcholine (SM16), and N-lignoceroyl-D-erythro-sphingosyl-phosphatidylcholine (SM24). The bilayers׳ compositions are based on lipidomic studies of PC-3 prostate cancer cells and exosomes discussed in Llorente et al. (2013) [1], showing an increase in the section of long-tail lipid species (SOPS, SOPE, and SM24) in the exosomes. Former knowledge about lipid asymmetry in cell membranes was accounted for in the models, meaning that the model of the inner leaflet is composed of a mixture of PC, PS, PE, and cholesterol, while the extracellular leaflet is composed of SM, PC and cholesterol discussed in Van Meer et al. (2008) [2]. The provided data include lipids׳ topologies, equilibrated structures of asymmetric bilayers, all force field parameters, and input files with parameters describing simulation conditions (md.mdp). The data is associated with the research article "Interdigitation of Long-Chain Sphingomyelin Induces Coupling of Membrane Leaflets in a Cholesterol Dependent Manner" (Róg et al., 2016) [3].
Universal properties of relaxation and diffusion in condensed matter
International Nuclear Information System (INIS)
Ngai K L
2017-01-01
By and large the research communities today are not fully aware of the remarkable universality in the dynamic properties of many-body relaxation/diffusion processes manifested in experiments and simulations on condensed matter with diverse chemical compositions and physical structures. I shall demonstrate the universality first from the dynamic processes in glass-forming systems. This is reinforced by strikingly similar properties of different processes in contrasting interacting systems all having nothing to do with glass transition. The examples given here include glass-forming systems of diverse chemical compositions and physical structures, conductivity relaxation of ionic conductors (liquid, glassy, and crystalline), translation and orientation ordered phase of rigid molecule, and polymer chain dynamics. Universality is also found in the change of dynamics when dimension is reduced to nanometer size in widely different systems. The remarkable universality indicates that many-body relaxation/diffusion is governed by fundamental physics to be unveiled. One candidate is classical chaos on which the coupling model is based, Universal properties predicted by this model are in accord with diverse experiments and simulations. (paper)
CONVECTION IN CONDENSIBLE-RICH ATMOSPHERES
Energy Technology Data Exchange (ETDEWEB)
Ding, F. [Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637 (United States); Pierrehumbert, R. T., E-mail: fding@uchicago.edu [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom)
2016-05-01
Condensible substances are nearly ubiquitous in planetary atmospheres. For the most familiar case—water vapor in Earth’s present climate—the condensible gas is dilute, in the sense that its concentration is everywhere small relative to the noncondensible background gases. A wide variety of important planetary climate problems involve nondilute condensible substances. These include planets near or undergoing a water vapor runaway and planets near the outer edge of the conventional habitable zone, for which CO{sub 2} is the condensible. Standard representations of convection in climate models rely on several approximations appropriate only to the dilute limit, while nondilute convection differs in fundamental ways from dilute convection. In this paper, a simple parameterization of convection valid in the nondilute as well as dilute limits is derived and used to discuss the basic character of nondilute convection. The energy conservation properties of the scheme are discussed in detail and are verified in radiative-convective simulations. As a further illustration of the behavior of the scheme, results for a runaway greenhouse atmosphere for both steady instellation and seasonally varying instellation corresponding to a highly eccentric orbit are presented. The latter case illustrates that the high thermal inertia associated with latent heat in nondilute atmospheres can damp out the effects of even extreme seasonal forcing.
Condensation of F-Actin by Dimensional Reduction
Bruinsma, Robijn; Christian, Cyron; Mueller, Kei; Bausch, Andreas; Wall, Wolfgang
2012-02-01
We present a Brownian Dynamics simulation of the equilibrium condensation of F-actin in the presence of linker molecules. The filaments are modeled as worm-like chains, using finite element analysis. At low linker concentrations, the systems forms a gel whose physical properties do not depend on the linker molecules. If the linker concentration is increased then for isotropic linkers only a single mode of condensation is encountered: bundle formation. If the linker molecules impose a preferential angle between F-actin filaments, then condensation takes place either into a either a hexatic or squaratic two-dimensional liquid crystal phase or into a heterogeneous cluster. Condensation is driven by competition between linker and filament entropy, which imposes dimensional reduction on the F-actin aggregate.
Gravitino Condensates in the Early Universe and Inflation
Mavromatos, Nick E
2015-01-01
We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry (supergravity), entirely independent of any coupling to external matter. The goldstino mode associated with the breaking of (global) supersymmetry is "eaten" by the gravitino field, which becomes massive (via its own vacuum condensation) and breaks the local supersymmetry (supergravity) dynamically. The most natural association of gravitino condensates with inflation proceeds in an indirect way, via a Starobinsky-inflation-type phase. The higher-order curvature corrections of the (quantum) effective action of gravitino condensates induced by integrating out massive gravitino degrees of freedom in a curved space-time background, in the broken-supergravity phase, are responsible for inducing a scalar mode which inflates the Universe. The scenario is in agreement with Planck data phenomenology in a natural and phenomen...
Experimental study of steam condensation regime map for simplified spargers
International Nuclear Information System (INIS)
Kim, Y. S.; Yoon, Y. J.; Song, C. H.; Park, C. K.; Kang, H. S.; Jun, H. K.
2003-01-01
An experimental study was conducted to produce a condensation regime map for single-hole and 4-hole steam spargers using GIRLS facility. The regime map for a single-hole sparger was derived using parameters such as the frequency and magnitude of the dynamic pressure. For 4-hole sparager, the regime map was derived using the trends of sound and dynamic pressure. Using the single-hole and 4-hole data, a steam jet condensation regime map was suggested with respect to pool temperature and steam mass flux
Chiral condensate from the twisted mass Dirac operator spectrum
Energy Technology Data Exchange (ETDEWEB)
Cichy, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Garcia-Ramos, Elena [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany); Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Collaboration: European Twisted Mass Collaboration
2013-03-15
We present the results of our computation of the chiral condensate with N{sub f}=2 and N{sub f}=2+1+1 flavours of maximally twisted mass fermions. The condensate is determined from the Dirac operator spectrum, applying the spectral projector method proposed by Giusti and Luescher. We use 3 lattice spacings and several quark masses at each lattice spacing to reliably perform the chiral and continuum extrapolations. We study the effect of the dynamical strange and charm quarks by comparing our results for N{sub f}=2 and N{sub f}=2+1+1 dynamical flavours.
Pions as collective modes in the glueball condensate vacuum
Energy Technology Data Exchange (ETDEWEB)
Hansson, T.H.; Zahed, I.
1987-07-01
The glueball condensate vacuum model is extended to incorporate the effects of light quarks. The resulting model exhibits spontaneous breaking of chiral SU(2)/sub f/ symmetry, and has a new kind of collective excitations, pions, which are distinct from the usual bag-model-type states. The dynamics of the pions are described by a sigma model, and the parameters
Landau damping in trapped Bose condensed gases
Energy Technology Data Exchange (ETDEWEB)
Jackson, B; Zaremba, E [Department of Physics, Queen' s University, Kingston, ON K7L 3N6 (Canada)
2003-07-01
We study Landau damping in dilute Bose-Einstein condensed gases in both spherical and prolate ellipsoidal harmonic traps. We solve the Bogoliubov equations for the mode spectrum in both of these cases, and calculate the damping by summing over transitions between excited quasiparticle states. The results for the spherical case are compared to those obtained in the Hartree-Fock (HF) approximation, where the excitations take on a single-particle character, and excellent agreement between the two approaches is found. We have also taken the semiclassical limit of the HF approximation and obtain a novel expression for the Landau damping rate involving the time-dependent self-diffusion function of the thermal cloud. As a final approach, we study the decay of a condensate mode by making use of dynamical simulations in which both the condensate and thermal cloud are evolved explicitly as a function of time. A detailed comparison of all these methods over a wide range of sample sizes and trap geometries is presented.
High gliding fluid power generation system with fluid component separation and multiple condensers
Mahmoud, Ahmad M; Lee, Jaeseon; Radcliff, Thomas D
2014-10-14
An example power generation system includes a vapor generator, a turbine, a separator and a pump. In the separator, the multiple components of the working fluid are separated from each other and sent to separate condensers. Each of the separate condensers is configured for condensing a single component of the working fluid. Once each of the components condense back into a liquid form they are recombined and exhausted to a pump that in turn drives the working fluid back to the vapor generator.
Condenser retubing-criteria manual
International Nuclear Information System (INIS)
Impagliazzo, A.M.; Bell, R.J.; Curlett, P.L.; Gordon, H.L.
1982-05-01
The objective of this document is to provide engineering assistance to utilities involved in retubing steam surface condensers with corrosion-resistant materials, such as titanium, and the recently developed high alloy pit-resistant steels. Field tests and recent operating experience have shown titanium and at least one of the high alloy pit-resistant steels to be virtually immune to the usual forms of corrosion occurring in steam surface condensers. This, together with the trend toward elimination of copper alloys in the circulating water system, has caused many utilities to retube their condensers with these materials
Bose condensation in (random traps
Directory of Open Access Journals (Sweden)
V.A. Zagrebnov
2009-01-01
Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.
Bubbler condenser related research work. Present situation
International Nuclear Information System (INIS)
2001-02-01
Intensive discussions within the OECD Support Group on 'VVER-440 Bubbler Condenser Containment Research Work' between 1991 and 1994 demonstrated the need for supplementary research work to achieve an adequate level of basic knowledge. In 1994, the European Commission (EC) asked for a specific 'VVER-440/213 Bubble Condenser Qualification Feasibility Study', which was finished early in 1996, confirming the need for additional research in this field. The Feasibility study formed the basis for the Bubble Condenser Experimental Qualification Project (BCEQ) with two separate experimental activities to be executed within the frame of the PHARE/TACIS 2.13/95 project of the European Commission. A first activity served to study the thermal-hydraulic phenomena and the associated structure dynamic interactions. This part of the project was performed at EREC, in Elektrogorsk, Russia. The design of the test facility was based on the prototypical bubbler condenser configuration for the Hungarian Paks nuclear power plant. A second activity addressed the structural integrity of certain components of the bubbler condenser steel structures under DBA-typical conditions. This part of the project was performed at VUEZ, in Levice, Slovak Republic. The design of the components of this facility was based on the structural properties of the Dukovany and/or Bohunice nuclear power plants. A third component of the BCEQ project was specified later asking for analytical studies, which should be supported by a number of small-scale separate effects tests to be performed at SVUSS, in Bechovice, Czech Republic. The main experimental and analytical results of the BCEQ test campaigns have been presented and discussed within the frame of the 4. meeting of the Technical Advisory Committee to the BCEQ (Bubble Condenser Experimental Qualification) Project in Brussels in December 1999 and on occasion of the 11. OECD Support Group Meeting in Berlin in April 2000. The discussions had evidenced several
Ardita, I. N.; Subagia, I. W. A.
2018-01-01
The condensate water produced by indoor a split air conditioning is usually not utilized and thrown away into the environment. The result of measurement shows that the temperature of condensate water produced by split air conditioning is quite low, that is 19-22 °C at the rate of 16-20 mL / min and it has PH balance. Under such conditions, Air Condensate produced by split air conditioning should still be recovered as an additional cooling medium on the condenser. This research will re-investigate the use of condensate water as an intermittent additional cooling of the condenser to increase the cooling capacity and performance of the air conditioning system. This research is done by experimental method whose implementation includes; designing and manufacturing of experimental equipment, mounting measuring tools, experimental data retrieval, data processing and yield analysis. The experimental results show that the use of condensate water as an intermittent additional cooling medium on split air conditioning condenser can increase the refrigeration effect about 2%, cooling capacity about 4% and 7% of COP system. Experimental results also show a decrease in power consumption in the system compressor about 3%
Dissipative phenomena in condensed matter some applications
Dattagupta, Sushanta
2004-01-01
From the field of nonequilibrium statistical physics, this graduate- and research-level volume treats the modeling and characterization of dissipative phenomena. A variety of examples from diverse disciplines like condensed matter physics, materials science, metallurgy, chemical physics etc. are discussed. Dattagupta employs the broad framework of stochastic processes and master equation techniques to obtain models for a wide range of experimentally relevant phenomena such as classical and quantum Brownian motion, spin dynamics, kinetics of phase ordering, relaxation in glasses, dissipative tunneling. It provides a pedagogical exposition of current research material and will be useful to experimentalists, computational physicists and theorists.
A color magnetic vortex condensate in QCD
International Nuclear Information System (INIS)
Ambjoern, J.; Olesen, P.
1980-03-01
It is shown that there exists a very close analogy between a lattice of vorticies in a superconductor near the critical field and a condensate of color magnetic flux tubes due to the unstable mode in QCD. This analogy makes it possible to identify a dynamical Higgs field in QCD. It is shown that the color magnetic flux tubes are quantized in terms of the center group Z(2) in the SU(2) case. In the case of SU(N) it is possible to select a color direction of the field such that one has Z(N) quantization. (Auth.)
Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study
Energy Technology Data Exchange (ETDEWEB)
Pajunen, A. J.; Tedeschi, A. R.
2012-09-18
This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments.
Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study
International Nuclear Information System (INIS)
Pajunen, A. J.; Tedeschi, A. R.
2012-01-01
This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report. The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments
Efficient, Long-Life Biocidal Condenser Project
National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity in manned modules. Condensing surfaces...
Steam generators, turbines, and condensers. Volume six
International Nuclear Information System (INIS)
Anon.
1986-01-01
Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make?), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries)
Instability and dynamics of volatile thin films
Ji, Hangjie; Witelski, Thomas P.
2018-02-01
Volatile viscous fluids on partially wetting solid substrates can exhibit interesting interfacial instabilities and pattern formation. We study the dynamics of vapor condensation and fluid evaporation governed by a one-sided model in a low-Reynolds-number lubrication approximation incorporating surface tension, intermolecular effects, and evaporative fluxes. Parameter ranges for evaporation-dominated and condensation-dominated regimes and a critical case are identified. Interfacial instabilities driven by the competition between the disjoining pressure and evaporative effects are studied via linear stability analysis. Transient pattern formation in nearly flat evolving films in the critical case is investigated. In the weak evaporation limit unstable modes of finite-amplitude nonuniform steady states lead to rich droplet dynamics, including flattening, symmetry breaking, and droplet merging. Numerical simulations show that long-time behaviors leading to evaporation or condensation are sensitive to transitions between filmwise and dropwise dynamics.
Computational condensed matter physics
Indian Academy of Sciences (India)
However, the electronic structure based investigations of structural stabilities at high pressures involve tedious trial and error effort, which is avoided in the ab initio molecular dynamics simulations. ... Thus in some sense, it mimics the phenomena taking place during the cohesion of solids. Therefore significant changes are ...
OPTIMAL EVAPORATING AND CONDENSING TEMPERATURES ...
African Journals Online (AJOL)
ORC) in a hot and humid environment. A theoretical procedure is proposed for the determination of the optimal evaporation temperature (OET) and optimal condensing temperature (OCT) of a subcritical ORC plant, which is based on ...
Solar engineering - a condensed course
Energy Technology Data Exchange (ETDEWEB)
Broman, Lars
2011-11-15
The document represents the material covered in a condensed two-week course focusing on the most important thermal and PV solar energy engineering topics, while also providing some theoretical background.
Condensed Matter Nuclear Science
Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro
Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation
Dual-phase reactor plant with partitioned isolation condenser
Hui, Marvin M.
1992-01-01
A nuclear energy plant housing a boiling-water reactor utilizes an isolation condenser in which a single chamber is partitioned into a distributor plenum and a collector plenum. Steam accumulates in the distributor plenum and is conveyed to the collector plenum through an annular manifold that includes tubes extending through a condenser pool. The tubes provide for a transfer of heat from the steam, forming a condensate. The chamber has a disk-shaped base, a cylindrical sidewall, and a semispherical top. This geometry results in a compact design that exhibits significant performance and cost advantages over prior designs.
International Nuclear Information System (INIS)
Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K.
1991-09-01
This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m 3 /s resulted in stable thermal stratification whereas flows less than 0.1 m 3 /s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs
Energy Technology Data Exchange (ETDEWEB)
Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K. (Pacific Northwest Lab., Richland, WA (United States))
1991-09-01
This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between {approximately}0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m{sup 3}/s resulted in stable thermal stratification whereas flows less than 0.1 m{sup 3}/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs.
Goodman, Lawrence E
2001-01-01
Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.
Niepel, Mario; Molloy, Kelly R.; Williams, Rosemary; Farr, Julia C.; Meinema, Anne C.; Vecchietti, Nicholas; Cristea, Ileana M.; Chait, Brian T.; Rout, Michael P.; Strambio-De-Castillia, Caterina
2013-01-01
The basket of the nuclear pore complex (NPC) is generally depicted as a discrete structure of eight protein filaments that protrude into the nucleoplasm and converge in a ring distal to the NPC. We show that the yeast proteins Mlp1p and Mlp2p are necessary components of the nuclear basket and that they also embed the NPC within a dynamic protein network, whose extended interactome includes the spindle organizer, silencing factors, the proteasome, and key components of messenger ribonucleoproteins (mRNPs). Ultrastructural observations indicate that the basket reduces chromatin crowding around the central transporter of the NPC and might function as a docking site for mRNP during nuclear export. In addition, we show that the Mlps contribute to NPC positioning, nuclear stability, and nuclear envelope morphology. Our results suggest that the Mlps are multifunctional proteins linking the nuclear transport channel to multiple macromolecular complexes involved in the regulation of gene expression and chromatin maintenance. PMID:24152732
International Nuclear Information System (INIS)
2003-11-01
Safety analysis is an important tool for justifying the safety of nuclear power plants. Typically, this type of analysis is performed by means of system computer codes with one dimensional approximation for modelling real plant systems. However, in the nuclear area there are issues for which traditional treatment using one dimensional system codes is considered inadequate for modelling local flow and heat transfer phenomena. There is therefore increasing interest in the application of three dimensional computational fluid dynamics (CFD) codes as a supplement to or in combination with system codes. There are a number of both commercial (general purpose) CFD codes as well as special codes for nuclear safety applications available. With further progress in safety analysis techniques, the increasing use of CFD codes for nuclear applications is expected. At present, the main objective with respect to CFD codes is generally to improve confidence in the available analysis tools and to achieve a more reliable approach to safety relevant issues. An exchange of views and experience can facilitate and speed up progress in the implementation of this objective. Both the International Atomic Energy Agency (IAEA) and the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (OECD/NEA) believed that it would be advantageous to provide a forum for such an exchange. Therefore, within the framework of the Working Group on the Analysis and Management of Accidents of the NEA's Committee on the Safety of Nuclear Installations, the IAEA and the NEA agreed to jointly organize the Technical Meeting on the Use of Computational Fluid Dynamics Codes for Safety Analysis of Reactor Systems, including Containment. The meeting was held in Pisa, Italy, from 11 to 14 November 2002. The publication constitutes the report of the Technical Meeting. It includes short summaries of the presentations that were made and of the discussions as well as conclusions and
Condensation En Film Liquidesur Une Surface Verticale Bordant Un ...
African Journals Online (AJOL)
This study aims to obtain the necessary information for the characterization and the precision of the dynamics of the condensation phenomenon in order to ... show the effect of the permeability porous medium and inclination of the principal axes on the liquid film thickness, liquid mass flow rate and surface heat transfer rate.
Neutrons for matter exploration: neutron spectroscopy in condensed matter physics
International Nuclear Information System (INIS)
Kahn, R.
1997-01-01
The physical properties and the various uses of neutrons for characterizing structures (through neutron diffraction) and condensed matter dynamics (through Doppler effect), are reviewed. Results and potential observations are given for the different methods: neutron diffraction, small angle scattering, reflectometry, neutron inelastic scattering. The two CEA laboratories where these studies may be carried out are presented
Spontaneous symmetry breaking in spinor Bose-Einstein condensates
DEFF Research Database (Denmark)
Scherer, Manuel; Lücke, Bernd; Peise, Jan
2013-01-01
We present an analytical model for the theoretical analysis of spin dynamics and spontaneous symmetry breaking in a spinor Bose-Einstein condensate (BEC). This allows for an excellent intuitive understanding of the processes and provides good quantitative agreement with the experimental results...
Anomalous heat transport and condensation in convection of cryogenic helium
Czech Academy of Sciences Publication Activity Database
Urban, Pavel; Schmoranzer, D.; Hanzelka, Pavel; Sreenivasan, K. R.; Skrbek, L.
2013-01-01
Roč. 110, č. 20 (2013), s. 8036-8039 ISSN 0027-8424 R&D Projects: GA ČR GPP203/12/P897 Institutional support: RVO:68081731 Keywords : two-phase convection * temperature inversion * condensation * rain formation Subject RIV: BK - Fluid Dynamics Impact factor: 9.809, year: 2013
Laser Processed Condensing Heat Exchanger Technology Development
Hansen, Scott; Wright, Sarah; Wallace, Sarah; Hamilton, Tanner; Dennis, Alexander; Zuhlke, Craig; Roth, Nick; Sanders, John
2017-01-01
The reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. The Laser Processed Condensing Heat Exchanger project aims to solve these problems through the use of femtosecond laser processed surfaces, which have unique wetting properties and potentially exhibit anti-microbial growth properties. These surfaces were investigated to identify if they would be suitable candidates for a replacement CHX surface. Among the areas researched in this project include microbial growth testing, siloxane flow testing in which laser processed surfaces were exposed to siloxanes in an air stream, and manufacturability.
Fidelity of a Bose-Einstein condensates
International Nuclear Information System (INIS)
Liu Jie; Zhang Chuanwei; Niu Qian; Li Baowen
2006-01-01
We investigate fidelity for the quantum evolution of a Bose-Einstein condensate and reveal its general property with a simple model. We find the fidelity decay with time in various ways depending on the form of initial states as well as on mean-field dynamics. When the initial state is a coherent state, the fidelity decays with time in the ways of exponential, Gaussian, and power-law, having a close relation to the classical mean-field dynamics. With the initial state prepared as a maximally entangled state, we find the behavior of fidelity has no classical correspondence and observe a novel behavior of the fidelity: periodic revival, where the period is inversely proportional to the number of bosons and the perturbation strength. An experimental observation of the fidelity decay is suggested
Continuous condensation device for vapors in the atmosphere
International Nuclear Information System (INIS)
Tricot, M.
1983-01-01
The continuous condensation device for vapors from the atmosphere is such those in which this atmosphere circulates in contact with a cold source involving the condensation of these vapors. It includes a thermoelectric module using the Peltier effect; the hot side is bonded to a heat sink and the cold side is in contact with an insulated condensation chamber in which flows the atmosphere charged with vapors to be condensated. The condensation chamber has a metallic structure through which a low voltage direct current is passed; this structure has small blades with holes, through which the condensate flows under gravity in the lower part of the chamber which have a hole to evacuate this liquid. The thermoelectric module comprises an assembly of thermocouples made of an array of alloy plates. The temperature inside the condensation chamber is maintained at just above 0 0 C. This device is used for the sampling of atmosphere water especially in the determination of tritium content of the atmosphere around nuclear installations [fr
Entanglement phases as holographic duals of anyon condensates
Duivenvoorden, Kasper; Iqbal, Mohsin; Haegeman, Jutho; Verstraete, Frank; Schuch, Norbert
2017-06-01
Anyon condensation forms a mechanism that allows us to relate different topological phases. We study anyon condensation in the framework of projected entangled pair states (PEPS) where topological order is characterized through local symmetries of the entanglement. We show that anyon condensation is in one-to-one correspondence to the behavior of the virtual entanglement state at the boundary (i.e., the entanglement spectrum) under those symmetries, which encompasses both symmetry breaking and symmetry protected (SPT) order, and we use this to characterize all anyon condensations for Abelian double models through the structure of their entanglement spectrum. We illustrate our findings with the Z4 double model, which can give rise to both toric code and doubled semion order through condensation, distinguished by the SPT structure of their entanglement. Using the ability of our framework to directly measure order parameters for condensation and deconfinement, we numerically study the phase diagram of the model, including direct phase transitions between the doubled semion and the toric code phase, which are not described by anyon condensation.
Kinetic theory of collective exitations and damping in Bose-Einstein condensed gases
Al Khawaja, U.; Stoof, H.T.C.
2000-01-01
We calculate the frequencies and damping rates of the low-lying collective modes of a Bose-Einstein condensed gas at nonzero temperature. We use a complex nonlinear Schrödinger equation to determine the dynamics of the condensate atoms. In this manner we take into account both collisions between
Kinetic theory of collective excitations and damping in Bose-Einstein condensed gases
Al Khawaja, U.; Stoof, H.T.C.
2000-01-01
We calculate the frequencies and damping rates of the low-lying collective modes of a Bose-Einstein condensed gas at nonzero temperature. We use a complex nonlinear Schrödinger equation to determine the dynamics of the condensate atoms, and couple it to a Boltzmann equation for the noncondensate
Condensation: the new deal; Condensation: la nouvelle donne
Energy Technology Data Exchange (ETDEWEB)
NONE
2002-06-01
The principle of condensation boilers is based on the recovery of the latent heat of the steam generated by the combustion of natural gas. This technology was introduced in France at the end of the 80's but failed in its promise because of the complexity of the equipments available at that time. Today, constructors' offer is more mature and reliable and the context has changed. This technology can conciliate three goals: a mastery of energy consumptions, the comfort of the user and the respect of environment. This meeting organized by the research center of Gaz de France (Cegibat), was a good opportunity to makes a status of the market of individual condensation systems in France and in Europe, to present the situation of this technology today and the 10 golden rules for the fitting and maintenance of individual condensation boilers, and to present some technical references, examples and results of today's offer. (J.S.)
Multiple atomic dark solitons in cigar-shaped Bose-Einstein condensates
International Nuclear Information System (INIS)
Theocharis, G.; Kevrekidis, P. G.; Weller, A.; Ronzheimer, J. P.; Gross, C.; Oberthaler, M. K.; Frantzeskakis, D. J.
2010-01-01
We consider the stability and dynamics of multiple dark solitons in cigar-shaped Bose-Einstein condensates. Our study is motivated by the fact that multiple matter-wave dark solitons may naturally form in such settings as per our recent work [Phys. Rev. Lett. 101, 130401 (2008)]. First, we study the dark soliton interactions and show that the dynamics of well-separated solitons (i.e., ones that undergo a collision with relatively low velocities) can be analyzed by means of particle-like equations of motion. The latter take into regard the repulsion between solitons (via an effective repulsive potential) and the confinement and dimensionality of the system (via an effective parabolic trap for each soliton). Next, based on the fact that stationary, well-separated dark multisoliton states emerge as a nonlinear continuation of the appropriate excited eigenstates of the quantum harmonic oscillator, we use a Bogoliubov-de Gennes analysis to systematically study the stability of such structures. We find that for a sufficiently large number of atoms, multiple soliton states are dynamically stable, while for a small number of atoms, we predict a dynamical instability emerging from resonance effects between the eigenfrequencies of the soliton modes and the intrinsic excitation frequencies of the condensate. Finally, we present experimental realizations of multisoliton states including a three-soliton state consisting of two solitons oscillating around a stationary one and compare the relevant results to the predictions of the theoretical mean-field model.
Resource Letter HCMP-1: History of Condensed Matter Physics
Martin, Joseph D.
2017-02-01
This Resource Letter provides a guide to the literature on the history of condensed matter physics, including discussions of the development of the field and strategies for approaching its complicated historical trajectory. Following the presentation of general resources, journal articles and books are cited for the following topics: conceptual development; institutional and community structure; social, cultural, and political history; and connections between condensed matter physics and technology.
Film Condensation of Steam on Externally Finned Horizontal Tubes.
1985-03-01
34. 7 e - Fin Height -F - Property Function g - Acceleration of Gravity G - Condensate Flow Rate Gf - Rate of Condensate Formation h - Steam...interaction of gravitational and surface-tension forces lead to complex - three-dimensional flow patterns, which are further dependent on fin spacing, height...and thickness. Other variables include heat flux, vapor shear, tube diameter, fin shape and fuid properties just to name a few. In view ofL the
Global variability of cloud condensation nuclei concentrations
Makkonen, Risto; Krüger, Olaf
2017-04-01
Atmospheric aerosols can influence cloud optical and dynamical processes by acting as cloud condensation nuclei (CCN). Globally, these indirect aerosol effects are significant to the radiative budget as well as a source of high uncertainty in anthropogenic radiative forcing. While historically many global climate models have fixed CCN concentrations to a certain level, most state-of-the-art models calculate aerosol-cloud interactions with sophisticated methodologies based on interactively simulated aerosol size distributions. However, due to scarcity of atmospheric observations simulated global CCN concentrations remain poorly constrained. Here we assess global CCN variability with a climate model, and attribute potential trends during 2000-2010 to changes in emissions and meteorological fields. Here we have used ECHAM5.5-HAM2 with model M7 microphysical aerosol model. The model has been upgraded with a secondary organic aerosol (SOA) scheme including ELVOCs. Dust and sea salt emissions are calculated online, based on wind speed and hydrology. Each experiment is 11 years, analysed after a 6-month spin-up period. The MODIS CCN product (Terra platform) is used to evaluate model performance throughout 2000-2010. While optical remote observation of CCN column includes several deficiencies, the products serves as a proxy for changes during the simulation period. In our analysis we utilize the observed and simulated vertical column integrated CCN concentration, and limit our analysis only over marine regions. Simulated annual CCN column densities reach 2ṡ108 cm-2 near strong source regions in central Africa, Arabian Sea, Bay of Bengal and China sea. The spatial concentration gradient in CCN(0.2%) is steep, and column densities drop to pattern of high temporal correlation is found over North Atlantic ocean, extending throughout Europe and up to Gulf of Mexico. All of these regions show a generally decreasing trend throughout the decade in control simulations and MODIS
Exploring the thermodynamics of Bose-Einstein condensation in a homogeneous atomic gas
Schmidutz, Tobias; Gotlibovych, Igor; Gaunt, Alexander; Smith, Robert; Hadzibabic, Zoran
2013-05-01
Atomic Bose-Einstein condensates have traditionally been produced in harmonic traps and only very recently it became possible to attain condensation in a homogeneous gas [A.L. Gaunt et al., arXiv:1212.4453]. In this talk we will present our new experimental results on the thermodynamics of condensation in a homogeneous weakly interacting Bose gas. We perform a systematic study of the tuning of the critical temperature with system parameters, the saturation of the thermal components in a partially condensed sample, and the total energy of the gas. We also study the dynamics of cooling in a uniform gas.
Sonic black holes in dilute Bose-Einstein condensates
Garay, L. J.; Anglin, J. R.; Cirac, J. I.; Zoller, P.
2000-01-01
The sonic analog of a gravitational black hole in dilute-gas Bose-Einstein condensates is investigated. It is shown that there exist both dynamically stable and unstable configurations which, in the hydrodynamic limit, exhibit behaviors completely analogous to that of gravitational black holes. The dynamical instabilities involve the creation of quasiparticle pairs in positive and negative energy states. We illustrate these features in two qualitatively different one-dimensional models, namel...
Bose-Einstein condensation of light: general theory.
Sob'yanin, Denis Nikolaevich
2013-08-01
A theory of Bose-Einstein condensation of light in a dye-filled optical microcavity is presented. The theory is based on the hierarchical maximum entropy principle and allows one to investigate the fluctuating behavior of the photon gas in the microcavity for all numbers of photons, dye molecules, and excitations at all temperatures, including the whole critical region. The master equation describing the interaction between photons and dye molecules in the microcavity is derived and the equivalence between the hierarchical maximum entropy principle and the master equation approach is shown. The cases of a fixed mean total photon number and a fixed total excitation number are considered, and a much sharper, nonparabolic onset of a macroscopic Bose-Einstein condensation of light in the latter case is demonstrated. The theory does not use the grand canonical approximation, takes into account the photon polarization degeneracy, and exactly describes the microscopic, mesoscopic, and macroscopic Bose-Einstein condensation of light. Under certain conditions, it predicts sub-Poissonian statistics of the photon condensate and the polarized photon condensate, and a universal relation takes place between the degrees of second-order coherence for these condensates. In the macroscopic case, there appear a sharp jump in the degrees of second-order coherence, a sharp jump and kink in the reduced standard deviations of the fluctuating numbers of photons in the polarized and whole condensates, and a sharp peak, a cusp, of the Mandel parameter for the whole condensate in the critical region. The possibility of nonclassical light generation in the microcavity with the photon Bose-Einstein condensate is predicted.
Cieplak-Rotowska, Maja K.; Tarnowski, Krzysztof; Rubin, Marcin; Fabian, Marc R.; Sonenberg, Nahum; Dadlez, Michal; Niedzwiecka, Anna
2018-01-01
The human GW182 protein plays an essential role in micro(mi)RNA-dependent gene silencing. miRNA silencing is mediated, in part, by a GW182 C-terminal region called the silencing domain, which interacts with the poly(A) binding protein and the CCR4-NOT deadenylase complex to repress protein synthesis. Structural studies of this GW182 fragment are challenging due to its predicted intrinsically disordered character, except for its RRM domain. However, detailed insights into the properties of proteins containing disordered regions can be provided by hydrogen-deuterium exchange mass spectrometry (HDX/MS). In this work, we applied HDX/MS to define the structural state of the GW182 silencing domain. HDX/MS analysis revealed that this domain is clearly divided into a natively unstructured part, including the CCR4-NOT interacting motif 1, and a distinct RRM domain. The GW182 RRM has a very dynamic structure, since water molecules can penetrate the whole domain in 2 h. The finding of this high structural dynamics sheds new light on the RRM structure. Though this domain is one of the most frequently occurring canonical protein domains in eukaryotes, these results are - to our knowledge - the first HDX/MS characteristics of an RRM. The HDX/MS studies show also that the α2 helix of the RRM can display EX1 behavior after a freezing-thawing cycle. This means that the RRM structure is sensitive to environmental conditions and can change its conformation, which suggests that the state of the RRM containing proteins should be checked by HDX/MS in regard of the conformational uniformity. [Figure not available: see fulltext.
Perrier, Erica T; Pavol, Michael J; Hoffman, Mark A
2011-07-01
The purpose of this research was to compare the effects of a warm-up with static vs. dynamic stretching on countermovement jump (CMJ) height, reaction time, and low-back and hamstring flexibility and to determine whether any observed performance deficits would persist throughout a series of CMJs. Twenty-one recreationally active men (24.4 ± 4.5 years) completed 3 data collection sessions. Each session included a 5-minute treadmill jog followed by 1 of the stretch treatments: no stretching (NS), static stretching (SS), or dynamic stretching (DS). After the jog and stretch treatment, the participant performed a sit-and-reach test. Next, the participant completed a series of 10 maximal-effort CMJs, during which he was asked to jump as quickly as possible after seeing a visual stimulus (light). The CMJ height and reaction time were determined from measured ground reaction forces. A treatment × jump repeated-measures analysis of variance for CMJ height revealed a significant main effect of treatment (p = 0.004). The CMJ height was greater for DS (43.0 cm) than for NS (41.4 cm) and SS (41.9 cm) and was not less for SS than for NS. Analysis also revealed a significant main effect of jump (p = 0.005) on CMJ height: Jump height decreased from the early to the late jumps. The analysis of reaction time showed no significant effect of treatment. Treatment had a main effect (p flexibility, however. Flexibility was greater after both SS and DS compared to after NS, with no difference in flexibility between SS and DS. Athletes in sports requiring lower-extremity power should use DS techniques in warm-up to enhance flexibility while improving performance.
Introduction. Cosmology meets condensed matter.
Kibble, T W B; Pickett, G R
2008-08-28
At first sight, low-temperature condensed-matter physics and early Universe cosmology seem worlds apart. Yet, in the last few years a remarkable synergy has developed between the two. It has emerged that, in terms of their mathematical description, there are surprisingly close parallels between them. This interplay has been the subject of a very successful European Science Foundation (ESF) programme entitled COSLAB ('Cosmology in the Laboratory') that ran from 2001 to 2006, itself built on an earlier ESF network called TOPDEF ('Topological Defects: Non-equilibrium Field Theory in Particle Physics, Condensed Matter and Cosmology'). The articles presented in this issue of Philosophical Transactions A are based on talks given at the Royal Society Discussion Meeting 'Cosmology meets condensed matter', held on 28 and 29 January 2008. Many of the speakers had participated earlier in the COSLAB programme, but the strength of the field is illustrated by the presence also of quite a few new participants.
Condensational theory of stationary tornadoes
International Nuclear Information System (INIS)
Makarieva, A.M.; Gorshkov, V.G.; Nefiodov, A.V.
2011-01-01
Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated. -- Highlights: → Water vapor condensation causes a logarithmic drop of air pressure towards tornado center. → The first ever theoretical description of tornado velocities is obtained. → The maximum vortex velocity grows logarithmically with decreasing tornado eye radius. → Air motion with high velocities can only develop in sufficiently large condensation areas.
Observation of a modulational instability in Bose-Einstein condensates
Everitt, P. J.; Sooriyabandara, M. A.; Guasoni, M.; Wigley, P. B.; Wei, C. H.; McDonald, G. D.; Hardman, K. S.; Manju, P.; Close, J. D.; Kuhn, C. C. N.; Szigeti, S. S.; Kivshar, Y. S.; Robins, N. P.
2017-10-01
We observe the breakup dynamics of an elongated cloud of condensed 85Rb atoms placed in an optical waveguide. The number of localized spatial components observed in the breakup is compared with the number of solitons predicted by a plane-wave stability analysis of the nonpolynomial nonlinear Schrödinger equation, an effective one-dimensional approximation of the Gross-Pitaevskii equation for cigar-shaped condensates. It is shown that the numbers predicted from the fastest growing sidebands are consistent with the experimental data, suggesting that modulational instability is the key underlying physical mechanism driving the breakup.
Transition to instability in a kicked Bose-Einstein condensate
International Nuclear Information System (INIS)
Zhang Chuanwei; Raizen, Mark G.; Liu Jie; Niu Qian
2004-01-01
A periodically kicked ring of a Bose-Einstein condensate is considered as a nonlinear generalization of the quantum kicked rotor. For weak interactions between atoms, periodic motion (antiresonance) becomes quasiperiodic (quantum beating) but remains stable. There exists a critical strength of interactions beyond which quasiperiodic motion becomes chaotic, resulting in an instability of the condensate manifested by exponential growth in the number of noncondensed atoms. Similar behavior is observed for dynamically localized states (essentially quasiperiodic motions), where stability remains for weak interactions but is destroyed by strong interactions
Bose-Einstein condensation in an ultra-hot gas of pumped magnons.
Serga, Alexander A; Tiberkevich, Vasil S; Sandweg, Christian W; Vasyuchka, Vitaliy I; Bozhko, Dmytro A; Chumak, Andrii V; Neumann, Timo; Obry, Björn; Melkov, Gennadii A; Slavin, Andrei N; Hillebrands, Burkard
2014-03-11
Bose-Einstein condensation of quasi-particles such as excitons, polaritons, magnons and photons is a fascinating quantum mechanical phenomenon. Unlike the Bose-Einstein condensation of real particles (like atoms), these processes do not require low temperatures, since the high densities of low-energy quasi-particles needed for the condensate to form can be produced via external pumping. Here we demonstrate that such a pumping can create remarkably high effective temperatures in a narrow spectral region of the lowest energy states in a magnon gas, resulting in strikingly unexpected transitional dynamics of Bose-Einstein magnon condensate: the density of the condensate increases immediately after the external magnon flow is switched off and initially decreases if it is switched on again. This behaviour finds explanation in a nonlinear 'evaporative supercooling' mechanism that couples the low-energy magnons overheated by pumping with all the other thermal magnons, removing the excess heat, and allowing Bose-Einstein condensate formation.
Condensation of sodium on a micromachined surface for AMTEC
International Nuclear Information System (INIS)
Crowley, C.J.; Izenson, M.G.
1993-01-01
A novel condenser component is being developed to enable Alkali Metal Thermal to Electric Conversion (AMTEC) technology to achieve two critical goals: (1) optimization of conversion efficiency and (2) microgravity fluid management. The first goal is achieved by minimizing parasitic radiation heat transfer losses for condensers with a large view factor to the high-temperature β double-prime-alumina surface. The condenser geometry includes a specially designed, micromachined surface where large capillary forces are used to manage the fluid distribution to accomplish the second goal. We present and discuss the results of separate effects experiments investigating the wetting and condensation behavior of sodium on this capillary surface. Test results show that the micromachined surface maintains a smooth, high reflective film of liquid sodium on the surface, which implies reduced parasitic losses and increased conversion efficiencies in AMTEC cells. Accomplishing this in an adverse gravity gradient demonstrates the potential for management of the fluid even under spacecraft acceleration conditions
Condensation Heat Transfer Performance of Nano- Engineered Cu Surfaces
Kim, Hyunsik; Nam, Youngsuk
2014-11-01
We investigated condensate mobility and resulting heat transfer performance on Cu based water repellent surfaces including hydrophobic, superhydrophobic and oil-infused surfaces. We observed the transient microscale condensation behaviours up to 3 hours with controlling the supersaturation level at 1.64. We experimentally characterized the nucleation density, droplet size distribution and growth rate, and then incorporated them into the developed condensation heat transfer model to compare the condensation heat transfer performance of each surface. Due to the spontaneous coalescence induced jumping, superhydrophobic surface can maintain the high heat transfer performance while other surfaces show a gradual decrease in heat transfer performance due to the increase in the thermal resistance across the growing droplets. We also quantified each thermal resistance values from the vapor to the surface through the droplets to find out the relative importance of each thermal resistance term.
Ignatova, V A; Katardjiev, I V
2003-01-01
The redistribution of the elements as a result of atomic relocations produced by the ions and the recoils due to the ballistic and transport processes is investigated by making use of a dynamic Monte Carlo code. Phenomena, such as radiation-enhanced diffusion (RED) and bombardment-induced segregation (BIS) triggered by the ion bombardment may also contribute to the migration of atoms within the target. In order to include both RED and BIS in the code, we suggest an approach which is considered as an extension of the binary collision approximation, i.e. it takes place 'simultaneously' with the cascade and acts as a correction to the particle redistribution for low energies. Both RED and BIS models are based on the common approach to treat the transport processes as a result of a random migration of point defects (vacancies and interstitials) according to a probability given by a pre-defined Gaussian. The models are tested and the influence of the diffusion and segregation is illustrated in the cases of 12 keV ...
Directory of Open Access Journals (Sweden)
Shaun Patrick Murphy
2014-07-01
Full Text Available The nuclear envelope (NE plays an essential role in meiotic telomere behavior and links the cytoplasm and nucleoplasm during homologous chromosome pairing and recombination in many eukaryotic species. Resident NE proteins including SUN (Sad-1/UNC-84 and KASH (Klarsicht/ANC-1/Syne-homology domain proteins are known to interact forming the Linker of Nucleoskeleton and Cytoskeleton (LINC complex that connects chromatin to the cytoskeleton. To investigate the possible cross-kingdom conservation of SUN protein functions in plant meiosis, we immunolocalized maize SUN2 using 3D microscopy of pollen mother cells from maize (Zea mays L., a large-genome plant model with a canonical NE zygotene-stage telomere bouquet. We detected SUN2 at the nuclear periphery and found that it exhibited a distinct belt-like structure that transitioned to a half-belt during the zygotene stage and back to a full belt during and beyond the pachytene stage. The zygotene-stage half-belt SUN structure was shown by 3D immuno-FISH to include the NE-associated telomere cluster that defines the bouquet stage and coincides with homologous chromosome synapsis. Microtubule and filamentous actin staining patterns did not show any obvious belt or a retracted-like structure other than a general enrichment of tubulin staining distributed widely around the nucleus and throughout the cytoplasm. Genetic disruption of the meiotic SUN belt staining patterns with three different meiosis-specific mutants, desynaptic (dy1, asynaptic1 (as1, and divergent spindle1 (dv1 provides additional evidence for the role of the nuclear envelope in meiotic chromosome behavior. Taking into account all of the observations from this study, we propose that the maize SUN belt is directly or indirectly involved in meiotic telomere dynamics, chromosome synapsis, and possibly integration of signals and forces across the meiotic prophase nuclear envelope.
Electronic Pumping of Quasiequilibrium Bose-Einstein-Condensed Magnons
Bender, Scott A.; Duine, Rembert A.; Tserkovnyak, Yaroslav
2012-06-01
We theoretically investigate spin transfer between a system of quasiequilibrated Bose-Einstein-condensed magnons in an insulator in direct contact with a conductor. While charge transfer is prohibited across the interface, spin transport arises from the exchange coupling between insulator and conductor spins. In a normal insulator phase, spin transport is governed solely by the presence of thermal and spin-diffusive gradients; the presence of Bose-Einstein condensation (BEC), meanwhile, gives rise to a temperature-independent condensate spin current. Depending on the thermodynamic bias of the system, spin may flow in either direction across the interface, engendering the possibility of a dynamical phase transition of magnons. We discuss the experimental feasibility of observing a BEC steady state (fomented by a spin Seebeck effect), which is contrasted to the more familiar spin-transfer-induced classical instabilities.
The chiral condensate in matter
International Nuclear Information System (INIS)
Brockmann, R.; Weise, W.
1995-01-01
The change of the chiral condensate in dense matter is discussed. Especially the higher order terms in the density of nuclear matter are evaluated (in the relativistic Brueckner-Hartree-Fock approach). Implications for nuclear physics and relativistic heavy ion collisions are discussed, such as the strong Dirac scalar mean field that results from the density dependence of . (orig.)
KAON CONDENSATION IN NEUTRON STARS.
Energy Technology Data Exchange (ETDEWEB)
RAMOS,A.; SCHAFFNER-BIELICH,J.; WAMBACH,J.
2001-04-24
We discuss the kaon-nucleon interaction and its consequences for the change of the properties of the kaon in the medium. The onset of kaon condensation in neutron stars under various scenarios as well its effects for neutron star properties are reviewed.
Approaching Bose-Einstein Condensation
Ferrari, Loris
2011-01-01
Bose-Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial…
Comparison of condensation correlations in CATHARE for modelling isolation condenser experiment
International Nuclear Information System (INIS)
Sorjonen, J.; Kalli, H.
1996-01-01
CATHARE is a thermal-hydraulic computer code developed at the Centre d'Etudes Nucleaires de Grenoble (CENG) for nuclear power plant safety analysis. Behaviour of a new Cathare condensation correlation have been studied. The code has been applied to Isolation Condenser (IC) experiment conducted in PIPER-ONE facility. PIPER-ONE simulates a General Electric BWR-6 with volume and height scaling ratios 1/2200 and 1/1, respectively. The facility is installed at Dipartimento di Costruzioni Meccaniche e Nucleari of Pisa University. The facility was equipped with an once-through heat exchanger immersed in a pool of ambient temperature water, installed roughly 10 m above the core, in the aim to reproduce qualitatively the phenomenologies expected for Isolation Condenser in the Simplified BWR (SBWR). Experiment PO-IC-02 included two subsequent power levels with initial pressure of 5.1 MPa. The IC was active during the whole experiment except in the time period between the two different power levels. A previous calculation of above mentioned experiment by Cathare2 V1.3E showed some lacks in the condensation correlation of the code. A new correlation has been developed in Centre d'Etudes Nucleaires de Grenoble (CENG). The new calculation of the PO-IC-02 experiment by Cathare2 Vl.3U 1 with the new correlation gave results consistent with the experiment in the condensing zone of the IC. Also the overall pressure trend was reproduced with estimated heat losses to the environment. A comparison with previously obtained Relap5/Mod3. 1 results is also shown in the present document. (author) (18 refs.)
Implementation of quantum logic gates using coupled Bose-Einstein condensates
Energy Technology Data Exchange (ETDEWEB)
Luiz, F.S. [Universidade Federal de Sao Carlos (UFSCar), Sao Carlos, SP (Brazil). Departamento de Fisica; Duzzioni, E.I. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Fisica; Sanz, L., E-mail: lsanz@infis.ufu.br [Universidade Federal de Uberlandia (UFU), MG (Brazil). Instituto de Fisica
2015-10-15
In this work, we are interested in the implementation of single-qubit gates on coupled Bose-Einstein condensates (BECs). The system, a feasible candidate for a qubit, consists of condensed atoms in different hyperfine levels coupled by a two-photon transition. It is well established that the dynamics of coupled BECs can be described by the two-mode Hamiltonian that takes into account the confinement potential of the trap and the effects of collisions associated with each condensate. Other effects, such as collisions between atoms belonging to different BECs and detuning, are included in this approach. We demonstrate how to implement two types of quantum logic gates: population-transfer gates (NOT, Ŷ, and Hadamard), which require a population inversion between hyperfine levels, and phase gates (Z{sup ^}, Ŝ and T{sup ^}), which require self-trapping. We also discuss the experimental feasibility by evaluating the robustness of quantum gates against variations of physical parameters outside of the ideal conditions for the implementation of each quantum logic gate. (author)
Spagnol, Stephen T.; Dahl, Kris Noel
2016-01-01
The linear sequence of DNA encodes access to the complete set of proteins that carry out cellular functions. Yet, much of the functionality appropriate for each cell is nested within layers of dynamic regulation and organization, including a hierarchy of chromatin structural states and spatial arrangement within the nucleus. There remain limitations in our understanding of gene expression within the context of nuclear organization from an inability to characterize hierarchical chromatin organization in situ. Here we demonstrate the use of fluorescence lifetime imaging microscopy (FLIM) to quantify and spatially resolve chromatin condensation state using cell-permeable, DNA-binding dyes (Hoechst 33342 and PicoGreen). Through in vitro and in situ experiments we demonstrate the sensitivity of fluorescence lifetime to condensation state through the mechanical effects that accompany the structural changes and are reflected through altered viscosity. The establishment of FLIM for resolving and quantifying chromatin condensation state opens the door for single-measurement mechanical studies of the nucleus and for characterizing the role of genome structure and organization in nuclear processes that accompany physiological and pathological changes. PMID:26765322
Modeling of Kerena Emergency Condenser
Bryk, Rafał; Schmidt, Holger; Mull, Thomas; Wagner, Thomas; Ganzmann, Ingo; Herbst, Oliver
2017-12-01
KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA) was built in Karlstein, Germany. The emergency condenser (EC) system transfers heat from the reactor pressure vessel (RPV) to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA). The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.
Modeling of Kerena Emergency Condenser
Directory of Open Access Journals (Sweden)
Bryk Rafał
2017-12-01
Full Text Available KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA was built in Karlstein, Germany. The emergency condenser (EC system transfers heat from the reactor pressure vessel (RPV to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA. The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.
Construction of the blowdown and condensation loop
Energy Technology Data Exchange (ETDEWEB)
Park, Choon Kyung; Song, Chul Kyung; Cho, Seok; Chun, S. Y.; Chung, Moon Ki
1997-12-01
The blowdown and condensation loop (B and C loop) has been constructed to get experimental data for designing the safety depressurization system (SDS) and steam sparger which are considered to implement in the Korea Next Generation Reactor (KNGR). In this report, system description on the B and C loop is given in detail, which includes the drawings and technical specification of each component, instrumentation and control system, and the operational procedures and the results of the performance testing. (author). 7 refs., 11 tabs., 48 figs.
Potentially Prebiotic Syntheses of Condensed Phosphates
Keefe, Anthony D.; Miller, Stanley L.
1996-01-01
In view of the importance of a prebiotic source of high energy phosphates, we have investigated a number of potentially prebiotic processes to produce condensed phosphates from orthophosphate and cyclic trimetaphosphate from tripolyphosphate. The reagents investigated include polymerizing nitriles, acid anhydrides, lactones, hexamethylene tetramine and carbon suboxide. A number of these processes give substantial yields of pyrophosphate from orthophosphate and trimetaphosphate from tripolyphosphate. Although these reactions may have been applicable in local areas, they are not sufficiently robust to have been of importance in the prebiotic open ocean.
Hidden Scale Invariance in Condensed Matter
DEFF Research Database (Denmark)
Dyre, J. C.
2014-01-01
. This means that the phase diagram becomes effectively one-dimensional with regard to several physical properties. Liquids and solids with isomorphs include most or all van der Waals bonded systems and metals, as well as weakly ionic or dipolar systems. On the other hand, systems with directional bonding...... (hydrogen bonds or covalent bonds) or strong Coulomb forces generally do not exhibit hidden scale invariance. The article reviews the theory behind this picture of condensed matter and the evidence for it coming from computer simulations and experiments...
Yield stress materials in soft condensed matter
Bonn, Daniel; Denn, Morton M.; Berthier, Ludovic; Divoux, Thibaut; Manneville, Sébastien
2017-07-01
A comprehensive review is presented of the physical behavior of yield stress materials in soft condensed matter, which encompasses a broad range of materials from colloidal assemblies and gels to emulsions and non-Brownian suspensions. All these disordered materials display a nonlinear flow behavior in response to external mechanical forces due to the existence of a finite force threshold for flow to occur: the yield stress. Both the physical origin and rheological consequences associated with this nonlinear behavior are discussed and an overview is given of experimental techniques available to measure the yield stress. Recent progress is discussed concerning a microscopic theoretical description of the flow dynamics of yield stress materials, emphasizing, in particular, the role played by relaxation time scales, the interplay between shear flow and aging behavior, the existence of inhomogeneous shear flows and shear bands, wall slip, and nonlocal effects in confined geometries.
Liang, Zhi; Keblinski, Pawel
2018-02-01
Using molecular dynamics simulations, we study evaporation and condensation of fluid Ar in the presence of a non-condensable Ne gas in a nanochannel. The evaporation and condensation are driven by the temperature difference, ΔTL, between the evaporating and condensing liquid surfaces. The steady-state evaporation and condensation fluxes (JMD) are also affected by the Ne concentration, ρNe, and the nanochannel length. We find that across a wide range of ΔTL and ρNe, JMD is in good agreement with the prediction from Stefan's law and from Schrage relationships. Furthermore, for ΔTL less than ˜20% of the absolute average temperature, we find that both steady-state heat and mass fluxes are proportional to ΔTL. This allows us to determine the interfacial resistance to the heat and mass transfer and compare it with the corresponding resistances in the gas phase. In this context, we derive an analytical expression for the effective thermal conductivity of the gas region in the nanochannel and the mass transport interfacial resistance equivalent length, i.e., the length of the nanochannel for which the resistance to the mass flow is the same as the interfacial resistance to the mass flow.
POTENTIAL DIMETHYLMERCURY CONCENTRATION IN WATER & ORGANIC CONDENSATE
Energy Technology Data Exchange (ETDEWEB)
MEACHAM, J.E.
2004-12-28
This document bounds potential dimethylmercury concentration in water or organic condensate that might form in ventilation systems or cooler tank regions. Dimethylmercury concentrations were extremely low and would be below drinking water standards in the water condensate.
Design of spiral fin type condenser for hydrogen cryogenic distillation column
International Nuclear Information System (INIS)
Iwai, Yasunori; Nishi, Masataka; Yamanishi, Toshihiko
2005-08-01
The purpose of this paper is the proposal of new concept condenser for hydrogen cryogenic distillation column of Hydrogen Isotope Separation System (ISS) in a fusion reactor, and the establishment of numerical evaluation method of the hydrogen isotope inventory in the condenser. A large amount of hydrogen isotopes including high concentration of tritium, radioactive hydrogen isotope, has been handled in the cryogenic distillation column. Therefore, from the safety point of view, cryogenic coolant tube was commonly arranged to surround the condensed area to prevent the mixing of tritium into the coolant. This inevitable arrangement leads the difficulty in the minimization of the condenser. The scale of condenser has influence on the scale of the ISS and its earthquake-resistance. The spiral fin type condenser, which introduces fins inside it and in coolant tube to enhance heat exchange, is proposed as a new concept condenser for hydrogen cryogenic distillation column to miniaturize the condenser. The volume of spiral fin type condenser is estimated to become less than half of that of coil tube type condenser currently in use. Accordingly, it is found that the adoption of spiral fin type condenser realizes the significant miniaturization of the ISS. Moreover, the numerical evaluation method of the hydrogen isotope inventory in the condenser is proposed. The validity of this method was confirmed by the experimental data. The synthetic design of the condenser for the hydrogen cryogenic distillation column is achieved by the combination of the proposed new concept condenser with the numerical evaluation method of the hydrogen isotope inventory. (author)
Charge Screening in a Charged Condensate
International Nuclear Information System (INIS)
Gabadadze, Gregory; Rosen, Rachel A.
2009-01-01
We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.
Computations for a condenser. Experimental results
International Nuclear Information System (INIS)
Walden, Jean.
1975-01-01
Computations for condensers are presented with experimental results. The computations are concerned with the steam flux at the condenser input, and inside the tube bundle. Experimental results are given for the flux inside the condenser sleeve and the flow passing through the tube bundle [fr
Direct, nondestructive observation of a Bose condensate
Andrews, M.R.; Mewes, M.O.; van Druten, N.J.; Durfee, D.S.; Kurn, D.M.; Ketterle, W.
1996-01-01
The spatial observation of a Bose condensate is reported. Dispersive light scattering was used to observe the separation between the condensed and normal components of the Bose gas inside a magnetic trap. This technique is nondestructive, and about a hundred images of the same condensate can be
Droplet size distribution in condensing flow
Sidin, R.S.R.
2009-01-01
In this thesis, the problem of predicting the droplet size distribution in condensing ow is in- vestigated numerically and analytically. The work focuses on two types of problems: one where condensation occurs during the transonic expansion of a vapor-mixture, and a second one where condensation
DEFF Research Database (Denmark)
Walther, Jens Honore; Karvounis, Nikolas; Pang, Kar Mun
2016-01-01
on the sulfuric acid gas phase. A linear correlation is found between the fuel sulfur content and the sulfuric acid condensation rate. The initial in-cylinder water content is found not to affect the sulfuric acid condensation but it has a high impact on water condensation. The scavenging pressure level shows...... an inverse correlation between pressure and condensation rate due to change in the flame propagation speed. Finally, increasing the cylinder liner temperature significantly decreases water condensation but has a negligible influence on the condensation of sulfuric acid.......We present results from computational fluid dynamics simulations of the condensation of sulfuric acid (H2SO4) and water (H2O) in a large two-stroke marine diesel engine. The model uses a reduced n-heptane skeletal chemical mechanism coupled with a sulfur subsetto simulate the combustion process...
Fundamentals of condensed matter physics
Cohen, Marvin L
2016-01-01
Based on an established course and covering the fundamentals, central areas, and contemporary topics of this diverse field, Fundamentals of Condensed Matter Physics is a much-needed textbook for graduate students. The book begins with an introduction to the modern conceptual models of a solid from the points of view of interacting atoms and elementary excitations. It then provides students with a thorough grounding in electronic structure as a starting point to understand many properties of condensed matter systems - electronic, structural, vibrational, thermal, optical, transport, magnetic and superconductivity - and methods to calculate them. Taking readers through the concepts and techniques, the text gives both theoretically and experimentally inclined students the knowledge needed for research and teaching careers in this field. It features 200 illustrations, 40 worked examples and 150 homework problems for students to test their understanding. Solutions to the problems for instructors are available at w...
International Nuclear Information System (INIS)
Lemmon, E.C.; MacKay, D.B.
1978-01-01
LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation
Energy Technology Data Exchange (ETDEWEB)
Lemmon, E.C.; MacKay, D.B.
1978-05-26
LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation.
Advances in condensed matter optics
Chen, Liangyao; Jiang, Xunya; Jin, Kuijuan; Liu, Hui; Zhao, Haibin
2015-01-01
This book describes some of the more recent progresses and developmentsin the study of condensed matter optics in both theoretic and experimental fields.It will help readers, especially graduate students and scientists who are studying and working in the nano-photonic field, to understand more deeply the characteristics of light waves propagated in nano-structure-based materials with potential applications in the future.
Accelerators for condensed matter research
International Nuclear Information System (INIS)
Williams, P.R.
1990-01-01
The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)
Theory of laminar film condensation
Fujii, Tetsu
1991-01-01
Since the petroleum crisis in the 1970s, a lot of effort to save energy was made in industry, and remarkable achievements have been made. In the research and development concerning thermal energy, however, it was clar ified that one of the most important problems was manufacturing con densing systems with smaller size and higher performance. To solve this problem we need a method which synthesizes selections_ of the type of con denser, cooling tube and its arrangement, assessment of fouling on the cooling surfaces, consideration of transient characteristics of a condenser, etc. The majority of effort, however, has been to devise a surface element which enhances the heat transfer coefficient in condensation of a single or multicomponent vapor. Condensation phenomena are complexly affected by a lot of physical property values, and accordingly the results of theo retical research are expressed with several dimensionless parameters. On the other hand, the experimental research is limited to those with som...
Kaniyamattam, K; Elzo, M A; Cole, J B; De Vries, A
2016-10-01
The objective of this study was to develop a daily stochastic dynamic dairy simulation model that included multitrait genetics and to evaluate the effects of reduced genetic models and various reproduction and selection strategies on the genetic, technical, and financial performance of a dairy herd. The 12 correlated genetic traits included in the 2014 lifetime net merit (NM$) index were modeled for each animal. For each animal, a true breeding value (TBV) for each trait was calculated as the average of the sire's and dam's TBV, plus a fraction of the inbreeding and Mendelian sampling variability. Similarly, an environmental component for each trait was calculated and was partitioned into a permanent and a daily (temporary) effect. The combined TBV and environmental effects were converted into the phenotypic performance of each animal. Hence, genetics and phenotypic performances were associated. Estimated breeding values (EBV) were also simulated. Genetic trends for each trait for the service sire were based on expected trends in US Holsteins. Surplus heifers were culled based on various ranking criteria to maintain a herd size of 1,000 milking cows. In the first 8 scenarios, culling of surplus heifers was either random or based on the EBV of NM$. Four different genetic models, depending on the presence or absence of genetic trends or genetic and environmental correlations, or both, were evaluated to measure the effect of excluding multitrait genetics on animal performance. In the last 5 scenarios, the full genetic model was used and culling of surplus heifers was either random or based on the EBV of NM$ or the EBV of milk. Sexed semen use and reliability of the EBV were also varied. Each scenario was simulated for 15yr into the future. Results showed that genetic models without all 12 genetic trends and genetic and environmental correlations provided biased estimates of the genetic, technical, and financial performance of the dairy herd. Average TBV of NM$ of all
Equation of state of warm condensed matter
Energy Technology Data Exchange (ETDEWEB)
Barbee, T.W., III; Young, D.A.; Rogers, F.J.
1998-03-01
Recent advances in computational condensed matter theory have yielded accurate calculations of properties of materials. These calculations have, for the most part, focused on the low temperature (T=0) limit. An accurate determination of the equation of state (EOS) at finite temperature also requires knowledge of the behavior of the electron and ion thermal pressure as a function of T. Current approaches often interpolate between calculated T=0 results and approximations valid in the high T limit. Plasma physics-based approaches are accurate in the high temperature limit, but lose accuracy below T{approximately}T{sub Fermi}. We seek to ``connect up`` these two regimes by using ab initio finite temperature methods (including linear-response[1] based phonon calculations) to derive an equation of state of condensed matter for T{<=}T{sub Fermi}. We will present theoretical results for the principal Hugoniot of shocked materials, including carbon and aluminum, up to pressures P>100 GPa and temperatures T>10{sup 4}K, and compare our results with available experimental data.
Theory and design of heat exchanger : shell and tube condenser and reboiler
International Nuclear Information System (INIS)
Min, Ui Dong
1996-02-01
This book gives descriptions of shell and tube heat exchanger including from, sorts, structure like shell and shell side, channel, and sliding bar, basic design of heat exchanger, flow-induced vibration, shell side condenser, tube side condenser and design of basic structure of condenser by types, selection of reboiler type, kettle type reboiler, internal reboiler, pump through reboiler, design of reboiler like kettle and internal reboiler, and horizontal and vertical thermosyphon reboiler.
Cole, David J.
2012-04-01
An existing driver-vehicle model with neuromuscular dynamics is improved in the areas of cognitive delay, intrinsic muscle dynamics and alpha-gamma co-activation. The model is used to investigate the influence of steering torque feedback and neuromuscular dynamics on the vehicle response to lateral force disturbances. When steering torque feedback is present, it is found that the longitudinal position of the lateral disturbance has a significant influence on whether the driver's reflex response reinforces or attenuates the effect of the disturbance. The response to angle and torque overlay inputs to the steering system is also investigated. The presence of the steering torque feedback reduced the disturbing effect of torque overlay and angle overlay inputs. Reflex action reduced the disturbing effect of a torque overlay input, but increased the disturbing effect of an angle overlay input. Experiments on a driving simulator showed that measured handwheel angle response to an angle overlay input was consistent with the response predicted by the model with reflex action. However, there was significant intra- and inter-subject variability. The results highlight the significance of a driver's neuromuscular dynamics in determining the vehicle response to disturbances.
Direct contact condensation induced transition from stratified to slug flow
International Nuclear Information System (INIS)
Strubelj, Luka; Ezsoel, Gyoergy; Tiselj, Iztok
2010-01-01
Selected condensation-induced water hammer experiments performed on PMK-2 device were numerically modelled with three-dimensional two-fluid models of computer codes NEPTUNE C FD and CFX. Experimental setup consists of the horizontal pipe filled with the hot steam that is being slowly flooded with cold water. In most of the experimental cases, slow flooding of the pipe was abruptly interrupted by a strong slugging and water hammer, while in the selected experimental runs performed at higher initial pressures and temperatures that are analysed in the present work, the transition from the stratified into the slug flow was not accompanied by the water hammer pressure peak. That makes these cases more suitable tests for evaluation of the various condensation models in the horizontally stratified flows and puts them in the range of the available CFD (Computational Fluid Dynamics) codes. The key models for successful simulation appear to be the condensation model of the hot vapour on the cold liquid and the interfacial momentum transfer model. The surface renewal types of condensation correlations, developed for condensation in the stratified flows, were used in the simulations and were applied also in the regions of the slug flow. The 'large interface' model for inter-phase momentum transfer model was compared to the bubble drag model. The CFD simulations quantitatively captured the main phenomena of the experiments, while the stochastic nature of the particular condensation-induced water hammer experiments did not allow detailed prediction of the time and position of the slug formation in the pipe. We have clearly shown that even the selected experiments without water hammer present a tough test for the applied CFD codes, while modelling of the water hammer pressure peaks in two-phase flow, being a strongly compressible flow phenomena, is beyond the capability of the current CFD codes.
Reflux condensation behavior in SBLOCA tests of ATLAS facility
International Nuclear Information System (INIS)
Kim, Yeon-Sik; Park, Hyun-Sik; Cho, Seok; Choi, Ki-Yong; Kang, Kyoung-Ho
2017-01-01
Highlights: • Behavior of a reflux condensation heat transfer was investigated for SBLOCA tests. • Behavior of the reflux condensate in HL, SG inlet plenum, and U-tubes were evaluated. • Concept of a steam moisturizing phenomenon was introduced and discussed. • Test data and MARS calculations were compared and discussed on the reflux condensate. - Abstract: The behavior of the reflux condensation heat transfer in a hot side steam generator (SG) U-tubes during a cold leg (CL) pipe and a direct vessel injection (DVI) line break in small break loss-of-coolant accident (SBLOCA) tests of the ATLAS facility was investigated including MARS code calculations. Among the SBLOCA tests, a 6″-CL pipe and 50%-DVI line break SBLOCA test were selected to investigate the behavior of the reflux condensation. A reflux condensation heat transfer seemed to occur from the time the SG U-tubes were half-empty to near the loop seal clearing (LSC). It was found that a transition regime existed between the reflux condensation heat transfer and reverse heat transfer. The remaining reflux condensate in SG U-tubes owing to the counter-current flow limit (CCFL) phenomenon and a separating effect of liquid carry-over and/or entrainment with steam moisturizing seemed to affect the thermal-hydraulic behavior of the transition regime. It was also found that the steam flowrate of the loop pipings and SG U-tubes seemed to have a strong effect on the duration time of the transition regime, e.g., a larger steam flowrate results in a longer duration. From a comparison of the reflux condensation behavior between the ATLAS tests and MARS code calculations, overall qualitative agreements were found between the two cases. The largest discrepancies were found in the SG inlet plenum water level between the two cases, and the authors suggest that the combination effects of the remaining reflux condensate in SG U-tubes and a separating effect of liquid carry-over and/or entrainment with steam
International Nuclear Information System (INIS)
Raghavan, S.; Smerzi, A.; Fantoni, S.; Shenoy, S.R.
2001-03-01
We discuss the coherent atomic oscillations between two weakly coupled Bose-Einstein condensates. The weak link is provided by a laser barrier in a (possibly asymmetric) double-well trap or by Raman coupling between two condensates in different hyperfine levels. The boson Josephson junction (BJJ) dynamics is described by the two-mode nonlinear Gross-Pitaevskii equation that is solved analytically in terms of elliptic functions. The BJJ, being a neutral, isolated system, allows the investigations of dynamical regimes for the phase difference across the junction and for the population imbalance that are not accessible with superconductor Josephson junctions (SJJ's). These include oscillations with either or both of the following properties: (i) the time-averaged value of the phase is equal to π (π-phase oscillations); (ii) the average population imbalance is nonzero, in states with macroscopic quantum self-trapping. The (nonsinusoidal) generalization of the SJJ ac and plasma oscillations and the Shapiro resonance can also be observed. We predict the collapse of experimental data (corresponding to different trap geometries and the total number of condensate atoms) onto a single universal curve for the inverse period of oscillations. Analogies with Josephson oscillations between two weakly coupled reservoirs of 3 He-B and the internal Josephson effect in 3 He-A are also discussed. (author)
Universal Themes of Bose-Einstein Condensation
Proukakis, Nick P.; Snoke, David W.; Littlewood, Peter B.
2017-04-01
Foreword; List of contributors; Preface; Part I. Introduction: 1. Universality and Bose-Einstein condensation: perspectives on recent work D. W. Snoke, N. P. Proukakis, T. Giamarchi and P. B. Littlewood; 2. A history of Bose-Einstein condensation of atomic hydrogen T. Greytak and D. Kleppner; 3. Twenty years of atomic quantum gases: 1995-2015 W. Ketterle; 4. Introduction to polariton condensation P. B. Littlewood and A. Edelman; Part II. General Topics: Editorial notes; 5. The question of spontaneous symmetry breaking in condensates D. W. Snoke and A. J. Daley; 6. Effects of interactions on Bose-Einstein condensation R. P. Smith; 7. Formation of Bose-Einstein condensates M. J. Davis, T. M. Wright, T. Gasenzer, S. A. Gardiner and N. P. Proukakis; 8. Quenches, relaxation and pre-thermalization in an isolated quantum system T. Langen and J. Schmiedmayer; 9. Ultracold gases with intrinsic scale invariance C. Chin; 10. Berezinskii-Kosterlitz-Thouless phase of a driven-dissipative condensate N. Y. Kim, W. H. Nitsche and Y. Yamamoto; 11. Superfluidity and phase correlations of driven dissipative condensates J. Keeling, L. M. Sieberer, E. Altman, L. Chen, S. Diehl and J. Toner; 12. BEC to BCS crossover from superconductors to polaritons A. Edelman and P. B. Littlewood; Part III. Condensates in Atomic Physics: Editorial notes; 13. Probing and controlling strongly correlated quantum many-body systems using ultracold quantum gases I. Bloch; 14. Preparing and probing chern bands with cold atoms N. Goldman, N. R. Cooper and J. Dalibard; 15. Bose-Einstein condensates in artificial gauge fields L. J. LeBlanc and I. B. Spielman; 16. Second sound in ultracold atomic gases L. Pitaevskii and S. Stringari; 17. Quantum turbulence in atomic Bose-Einstein condensates N. G. Parker, A. J. Allen, C. F. Barenghi and N. P. Proukakis; 18. Spinor-dipolar aspects of Bose-Einstein condensation M. Ueda; Part IV. Condensates in Condensed Matter Physics: Editorial notes; 19. Bose
International Nuclear Information System (INIS)
Bandurski, Th.; Huggenberger, M.; Dreier, J.; Aubert, C.; Putz, F.; Gamble, R.E.; Yadigaroglu, G.
2001-01-01
Recently passive cooling systems have been designed for the long-term decay heat removal from the containment of Advanced Light Water Reactors. In particular, the long-term LOCA response of the Passive Containment Cooling System (PCCS) for the General Electric European Simplified Boiling Water Reactor (ESBWR) has been tested in the large-scale PANDA facility. The PANDA tests achieved the dual objectives of improving confidence in the performance of the passive heat removal mechanisms underlying the design of the system, and extending the database available for containment analysis code qualification. The tests conducted subject the PCCS to a variety of conditions representing design-basis and beyond-design-basis accident conditions. These include operation in the presence of both heavier and lighter than steam non-condensable gases, as well as a variety of asymmetric and challenging start-up conditions. The present paper addresses the transient distribution of non-condensables in PANDA, and their effect on (passive) condenser performance. (author)
Energy Technology Data Exchange (ETDEWEB)
Bandurski, Th.; Huggenberger, M.; Dreier, J.; Aubert, C.; Putz, F.; Gamble, R.E.; Yadigaroglu, G
2001-03-01
Recently passive cooling systems have been designed for the long-term decay heat removal from the containment of Advanced Light Water Reactors. In particular, the long-term LOCA response of the Passive Containment Cooling System (PCCS) for the General Electric European Simplified Boiling Water Reactor (ESBWR) has been tested in the large-scale PANDA facility. The PANDA tests achieved the dual objectives of improving confidence in the performance of the passive heat removal mechanisms underlying the design of the system, and extending the database available for containment analysis code qualification. The tests conducted subject the PCCS to a variety of conditions representing design-basis and beyond-design-basis accident conditions. These include operation in the presence of both heavier and lighter than steam non-condensable gases, as well as a variety of asymmetric and challenging start-up conditions. The present paper addresses the transient distribution of non-condensables in PANDA, and their effect on (passive) condenser performance. (author)
Directory of Open Access Journals (Sweden)
Ahmad Mamandi
2011-01-01
Full Text Available In this study, the nonlinear vibrations analysis of an inclined pinned-pinned self-weight Timoshenko beam made of linear, homogenous and isotropic material with a constant cross section and finite length subjected to a traveling mass/force with constant velocity is investigated. The nonlinear coupled partial differential equations of motion for the rotation of warped cross section, longitudinal and transverse displacements are derived using the Hamilton's principle. These nonlinear coupled PDEs are solved by applying the Galerkin's method to obtain dynamic responses of the beam. The dynamic magnification factor and normalized time histories of mid-point of the beam are obtained for various load velocity ratios and the outcome results have been compared to the results with those obtained from linear solution. The influence of the large deflections caused by a stretching effect due to the beam's fixed ends is captured. It was seen that existence of quadratic-cubic nonlinear terms in the nonlinear governing coupled PDEs of motion causes stiffening (hardening behavior of the dynamic responses of the self-weight beam under the act of a traveling mass as well as equivalent concentrated moving force. Furthermore, in a case where the object leaves the beam, its planar motion path is derived and the targeting accuracy is investigated and compared with those from the rigid solution assumption.
Kral, Q.; Thébault, P.; Charnoz, S.
2013-10-01
Context. In most current debris disc models, the dynamical and the collisional evolutions are studied separately with N-body and statistical codes, respectively, because of stringent computational constraints. In particular, incorporating collisional effects (especially destructive collisions) into an N-body scheme has proven a very arduous task because of the exponential increase of particles it would imply. Aims: We present here LIDT-DD, the first code able to mix both approaches in a fully self-consistent way. Our aim is for it to be generic enough to be applied to any astrophysical case where we expect dynamics and collisions to be deeply interlocked with one another: planets in discs, violent massive breakups, destabilized planetesimal belts, bright exozodiacal discs, etc. Methods: The code takes its basic architecture from the LIDT3D algorithm for protoplanetary discs, but has been strongly modified and updated to handle the very constraining specificities of debris disc physics: high-velocity fragmenting collisions, radiation-pressure affected orbits, absence of gas that never relaxes initial conditions, etc. It has a 3D Lagrangian-Eulerian structure, where grains of a given size at a given location in a disc are grouped into super-particles or tracers whose orbits are evolved with an N-body code and whose mutual collisions are individually tracked and treated using a particle-in-a-box prescription designed to handle fragmenting impacts. To cope with the wide range of possible dynamics for same-sized particles at any given location in the disc, and in order not to lose important dynamical information, tracers are sorted and regrouped into dynamical families depending on their orbits. A complex reassignment routine that searches for redundant tracers in each family and reassignes them where they are needed, prevents the number of tracers from diverging. Results: The LIDT-DD code has been successfully tested on simplified cases for which robust results have
Condensation on slippery asymmetric bumps
Park, Kyoo-Chul; Kim, Philseok; Grinthal, Alison; He, Neil; Fox, David; Weaver, James C.; Aizenberg, Joanna
2016-03-01
Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be
Dry coolers and air-condensing units (Review)
Milman, O. O.; Anan'ev, P. A.
2016-03-01
The analysis of factors affecting the growth of shortage of freshwater is performed. The state and dynamics of the global market of dry coolers used at electric power plants are investigated. Substantial increase in number and maximum capacity of air-cooled condensers, which have been put into operation in the world in recent years, are noted. The key reasons facilitating the choice of developers of the dry coolers, in particular the independence of the location of thermal power plant from water sources, are enumerated. The main steam turbine heat removal schemes using air cooling are considered, their comparison of thermal efficiency is assessed, and the change of three important parameters, such as surface area of heat transfer, condensate pump flow, and pressure losses in the steam exhaust system, are estimated. It is shown that the most effective is the scheme of direct steam condensation in the heat-exchange tubes, but other schemes also have certain advantages. The air-cooling efficiency may be enhanced much more by using an air-cooling hybrid system: a combination of dry and wet cooling. The basic applied constructive solutions are shown: the arrangement of heat-exchange modules and the types of fans. The optimal mounting design of a fully shopassembled cooling system for heat-exchange modules is represented. Different types of heat-exchange tubes ribbing that take into account the operational features of cooling systems are shown. Heat transfer coefficients of the plants from different manufacturers are compared, and the main reasons for its decline are named. When using evaporative air cooling, it is possible to improve the efficiency of air-cooling units. The factors affecting the faultless performance of dry coolers (DC) and air-condensing units (ACU) and the ways of their elimination are described. A high velocity wind forcing reduces the efficiency of cooling systems and creates preconditions for the development of wind-driven devices. It is noted that
Integral Reactor Containment Condensation Model and Experimental Validation
Energy Technology Data Exchange (ETDEWEB)
Wu, Qiao [Oregon State Univ., Corvallis, OR (United States); Corradini, Michael [Univ. of Wisconsin, Madison, WI (United States)
2016-05-02
gas mass fraction. (4) The average condensation heat transfer coefficients measured from the water condensation rates through energy balance analysis are appropriate, however, with considerable uncertainties due to the heat loss and temperature distribution on the containment wall. With the consideration of the side wall conduction effects, the results indicate that the measured heat transfer coefficients in the tests is about 20% lower than the prediction of Dehbi’s correlation, mainly due to the side wall conduction effects. The investigation also indicates an increase in the condensation heat transfer coefficient at high containment pressure conditions, but the uncertainties invoked with this method appear to be substantial. (5) Non-condensable gas in the tests has little effects on the condensation heat transfer at high elevation measurement ports. It does affect the bottom measurements near the water level position. The results suggest that the heavier non-condensable gas is accumulated in the lower portion of the containment due to stratification in the narrow containment space. The overall effects of the non-condensable gas on the heat transfer process should thus be negligible for tall containments of narrow condensation spaces in most SMR designs. Therefore, the previous correlations with noncondensable gas effects are not appropriate to those small SMR containments due to the very poor mixing of steam and non-condensable gas. The MELCOR simulation results agree with the experimental data reasonably well. However, it is observed that the MELCOR overpredicts the heat flux for all analyzed tests. The MELCOR predicts that the heat fluxes for CCT’s approximately range from 30 to 45 kW/m2 whereas the experimental data (averaged) ranges from about 25 to 40 kW/m2. This may be due to the limited availability of liquid film models included in MELCOR. Also, it is believed that due to complex test geometry, measured temperature gradients across the heat transfer
Quantum tunnelling in condensed media
Kagan, Yu
1992-01-01
The essays in this book deal with of the problem of quantum tunnelling and related behavior of a microscopic or macroscopic system, which interacts strongly with an ""environment"" - this being some form of condensed matter. The ""system"" in question need not be physically distinct from its environment, but could, for example, be one particular degree of freedom on which attention is focussed, as in the case of the Josephson junction studied in several of the papers. This general problem has been studied in many hundreds, if not thousands, of articles in the literature, in contexts as diverse
Energy Technology Data Exchange (ETDEWEB)
Lebech, B. [ed.
2001-03-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 2000 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au)
Energy Technology Data Exchange (ETDEWEB)
Bechgaard, K.; Clausen, K.N.; Feidenhans`l, R.; Johannsen, I. [eds.
1999-04-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical properties of materials. The principal activities in the year 1998 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au) 2 tabs., 142 ills., 169 refs.
International Nuclear Information System (INIS)
Nielsen, M.; Bechgaard, K.; Clausen, K.N.; Feidenhans'l, R.; Johannsen, I.
1998-01-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 1997 are presented in this progress report. The research in physics in concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems in undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au)
International Nuclear Information System (INIS)
Bechgaard, K.; Clausen, K.N.; Feidenhans'l, R.; Johannsen, I.
1999-04-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical properties of materials. The principal activities in the year 1998 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au)
International Nuclear Information System (INIS)
Lebech, B.
2000-02-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 1999 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au)
Energy Technology Data Exchange (ETDEWEB)
Nielsen, M.; Bechgaard, K.; Clausen, K.N.; Feidenhans`l, R.; Johannsen, I. [eds.
1998-01-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 1997 are presented in this progress report. The research in physics in concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scale structures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems in undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au). 129 ills., 213 refs.
Energy Technology Data Exchange (ETDEWEB)
Lebech, B. [ed.
2000-02-01
The Condensed Matter Physics and Chemistry Department is concerned with both fundamental and applied research into the physical and chemical properties of materials. The principal activities in the year 1999 are presented in this progress report. The research in physics is concentrated on neutron and x-ray scattering measurements and the problems studied include two- and three-dimensional structures, magnetic ordering and spin dynamics, superconductivity, phase transitions and nano-scalestructures. The research in chemistry includes chemical synthesis and physico-chemical investigation of small molecules and polymers, with emphasis on polymers with new optical properties, block copolymers, surface-modified polymers, and supramolecular structures. Theoretical work related to these problems is undertaken, including Monte Carlo simulations, computer simulation of molecules and polymers and methods of data analysis. (au)
Charged ρ Meson Condensate in Neutron Stars within RMF Models
Directory of Open Access Journals (Sweden)
Konstantin A. Maslov
2017-12-01
Full Text Available Knowledge of the equation of state (EoS of cold and dense baryonic matter is essential for the description of properties of neutron stars (NSs. With an increase of the density, new baryon species can appear in NS matter, as well as various meson condensates. In previous works, we developed relativistic mean-field (RMF models with hyperons and Δ -isobars, which passed the majority of known experimental constraints, including the existence of a 2 M ⊙ neutron star. In this contribution, we present results of the inclusion of ρ − -meson condensation into these models. We have shown that, in one class of the models (so-called KVOR-based models, in which the additional stiffening procedure is introduced in the isoscalar sector, the condensation gives only a small contribution to the EoS. In another class of the models (MKVOR-based models with additional stiffening in isovector sector, the condensation can lead to a first-order phase transition and a substantial decrease of the NS mass. Nevertheless, in all resulting models, the condensation does not spoil the description of the experimental constraints.
Aerosol simulation including chemical and nuclear reactions
International Nuclear Information System (INIS)
Marwil, E.S.; Lemmon, E.C.
1985-01-01
The numerical simulation of aerosol transport, including the effects of chemical and nuclear reactions presents a challenging dynamic accounting problem. Particles of different sizes agglomerate and settle out due to various mechanisms, such as diffusion, diffusiophoresis, thermophoresis, gravitational settling, turbulent acceleration, and centrifugal acceleration. Particles also change size, due to the condensation and evaporation of materials on the particle. Heterogeneous chemical reactions occur at the interface between a particle and the suspending medium, or a surface and the gas in the aerosol. Homogeneous chemical reactions occur within the aersol suspending medium, within a particle, and on a surface. These reactions may include a phase change. Nuclear reactions occur in all locations. These spontaneous transmutations from one element form to another occur at greatly varying rates and may result in phase or chemical changes which complicate the accounting process. This paper presents an approach for inclusion of these effects on the transport of aerosols. The accounting system is very complex and results in a large set of stiff ordinary differential equations (ODEs). The techniques for numerical solution of these ODEs require special attention to achieve their solution in an efficient and affordable manner. 4 refs
Vortices and ring solitons in Bose-Einstein condensates
International Nuclear Information System (INIS)
Carr, L. D.; Clark, Charles W.
2006-01-01
The form and stability properties of axisymmetric and spherically symmetric stationary states in two and three dimensions, respectively, are elucidated for Bose-Einstein condensates. These states include the ground state, central vortices, and radial excitations of both. The latter are called ring solitons in two dimensions and spherical shells in three. The nonlinear Schroedinger equation is taken as the fundamental model; both extended and harmonically trapped condensates are considered. It is found that the instability times of ring solitons can be long compared to experimental time scales, making them effectively stable over the lifetime of an experiment
Langmuir condensation by spontaneous scattering off electrons in two dimensions
International Nuclear Information System (INIS)
Ziebell, L F; Yoon, P H; Gaelzer, R; Pavan, J
2012-01-01
In a pair of recent papers (Ziebell et al 2008 Phys. Plasmas 15 032303, 2008 Plasma Phys. Control. Fusion 50 085011) it was shown, within the context of weak turbulence theory, that the Langmuir turbulence generated by the bump-in-tail instability does not lead to Langmuir condensation (or accumulation of wave energy and momentum in the long-wavelength regime) in two dimensions. The present analysis finds that it is important to include the spontaneous scattering off Langmuir turbulence of the electrons, which is ignored in the customary literature when compared with a similar process involving ions, in order to recover the condensation of Langmuir waves in two dimensions. (paper)
Proceedings of condensed papers on alternate energy sources
Energy Technology Data Exchange (ETDEWEB)
Veziroglu, T.N. (ed.)
1979-01-01
The conference covers the results of research and developments which have taken place during the last 2 years. It includes sessions on solar energy, ocean thermal energy, wind energy, hydro power, nuclear breeders and nuclear fusion, synthetic fuels from coal or waste, hydrogen production and uses. The volume of the Proceedings presents the papers and lectures in condensed format grouped by their subjects under 40 technical sessions. Condensed papers are presented for the 336 presentations; abstracts have previously appeared in the DOE Energy Data Base for 33 of the full-length papers.
Critical illumination condenser for x-ray lithography
Cohen, S.J.; Seppala, L.G.
1998-04-07
A critical illumination condenser system is disclosed, particularly adapted for use in extreme ultraviolet (EUV) projection lithography based on a ring field imaging system and a laser produced plasma source. The system uses three spherical mirrors and is capable of illuminating the extent of the mask plane by scanning either the primary mirror or the laser plasma source. The angles of radiation incident upon each mirror of the critical illumination condenser vary by less than eight (8) degrees. For example, the imaging system in which the critical illumination condenser is utilized has a 200 {micro}m source and requires a magnification of 26. The three spherical mirror system constitutes a two mirror inverse Cassegrain, or Schwarzschild configuration, with a 25% area obstruction (50% linear obstruction). The third mirror provides the final pupil and image relay. The mirrors include a multilayer reflective coating which is reflective over a narrow bandwidth. 6 figs.
Reconnection–Condensation Model for Solar Prominence Formation
Energy Technology Data Exchange (ETDEWEB)
Kaneko, Takafumi [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Yokoyama, Takaaki, E-mail: kaneko@isee.nagoya-u.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
2017-08-10
We propose a reconnection–condensation model in which topological change in a coronal magnetic field via reconnection triggers radiative condensation, thereby resulting in prominence formation. Previous observational studies have suggested that reconnection at a polarity inversion line of a coronal arcade field creates a flux rope that can sustain a prominence; however, they did not explain the origin of cool dense plasmas of prominences. Using three-dimensional magnetohydrodynamic simulations, including anisotropic nonlinear thermal conduction and optically thin radiative cooling, we demonstrate that reconnection can lead not only to flux rope formation but also to radiative condensation under a certain condition. In our model, this condition is described by the Field length, which is defined as the scale length for thermal balance between radiative cooling and thermal conduction. This critical condition depends weakly on the artificial background heating. The extreme ultraviolet emissions synthesized with our simulation results have good agreement with observational signatures reported in previous studies.
Preoperational test report, primary ventilation condenser cooling system
International Nuclear Information System (INIS)
Clifton, F.T.
1997-01-01
This represents the preoperational test report for the Primary Ventilation Condenser Cooling System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system uses a closed chilled water piping loop to provide offgas effluent cooling for tanks AY101, AY102, AZ1O1, AZ102; the offgas is cooled from a nominal 100 F to 40 F. Resulting condensation removes tritiated vapor from the exhaust stack stream. The piping system includes a package outdoor air-cooled water chiller with parallel redundant circulating pumps; the condenser coil is located inside a shielded ventilation equipment cell. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System
Preoperational test report, primary ventilation condenser cooling system
Energy Technology Data Exchange (ETDEWEB)
Clifton, F.T.
1997-10-29
This represents the preoperational test report for the Primary Ventilation Condenser Cooling System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system uses a closed chilled water piping loop to provide offgas effluent cooling for tanks AY101, AY102, AZ1O1, AZ102; the offgas is cooled from a nominal 100 F to 40 F. Resulting condensation removes tritiated vapor from the exhaust stack stream. The piping system includes a package outdoor air-cooled water chiller with parallel redundant circulating pumps; the condenser coil is located inside a shielded ventilation equipment cell. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.
On scalar condensate baryogenesis model
International Nuclear Information System (INIS)
Kiriloval, D.P.; Valchanov, T.V.
2004-09-01
We discuss the scalar field condensate baryogenesis model, which is among the baryogenesis scenarios preferred today, compatible with inflation. According to that model a complex scalar field φ, carrying baryon charge B≠0 is generated at inflation. The baryon excess in the Universe results from the φ decay at later stages of Universe evolution (T 15 GeV). We updated the model's parameters range according to the current observational cosmological constraints and analyzed numerically φ evolution after the inflationary stage till its decay φ → qq-barlγ. During that period oscillated with a decreasing amplitude due to Universe expansion and particle production processes due to the coupling of the field to fermions gφf 1 f 2 . It was shown that particle creation processes play an essential role for evolution and its final value. It may lead to a considerable decrease of the field's amplitude for large g and/or large H values, which reflects finally into strong damping of the baryon charge carried by the condensate. The analysis suggests that for a natural range of the model's parameters the observed value of the baryon asymmetry can be obtained and the model can serve as a successful baryogenesis model, compatible with inflation. (author)
Condensation induced water hammer safety
Energy Technology Data Exchange (ETDEWEB)
Gintner, M.A.
1997-03-10
Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer.
Muonic Chemistry in Condensed Matter
2002-01-01
When polarized muons (@m|+) stop in condensed matter, muonic atoms are formed in the final part of their range, and direct measurements of the @m|+-spin polarization are possible via the asymmetric decay into positrons. The hyperfine interaction determines the characteristic precession frequencies of the @m|+ spin in muonium, @w(Mu). Such frequencies can be altered by the interactions of the muonium's electron spin with the surrounding medium. The measurement of @w(Mu) in a condensed system is known often to provide unique information regarding the system. \\\\ \\\\ In particular, the use of muonium atoms as a light isotope of the simple reactive radical H|0 allows the investigation of fast reactions of radicals over a typical time scale 10|-|9~@$<$~t~@$<$~10|-|5~sec, which is determined by the instrumental resolution at one end and by the @m|+ lifetime at the other. \\\\ \\\\ In biological macromolecules transient radicals, such as the constituents of DNA itself, exist on a time scale of sub-microseconds, acco...
Magnon condensation and spin superfluidity
Bunkov, Yury M.; Safonov, Vladimir L.
2018-04-01
We consider the Bose-Einstein condensation (BEC) of quasi-equilibrium magnons which leads to spin superfluidity, the coherent quantum transfer of magnetization in magnetic material. The critical conditions for excited magnon density in ferro- and antiferromagnets, bulk and thin films, are estimated and discussed. It was demonstrated that only the highly populated region of the spectrum is responsible for the emergence of any BEC. This finding substantially simplifies the BEC theoretical analysis and is surely to be used for simulations. It is shown that the conditions of magnon BEC in the perpendicular magnetized YIG thin film is fulfillied at small angle, when signals are treated as excited spin waves. We also predict that the magnon BEC should occur in the antiferromagnetic hematite at room temperature at much lower excited magnon density compared to that of ferromagnetic YIG. Bogoliubov's theory of Bose-Einstein condensate is generalized to the case of multi-particle interactions. The six-magnon repulsive interaction may be responsible for the BEC stability in ferro- and antiferromagnets where the four-magnon interaction is attractive.
Condensation induced water hammer safety
International Nuclear Information System (INIS)
Gintner, M.A.
1997-01-01
Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer
Maury, Olivier; Poggiale, Jean-Christophe
2013-05-07
Individual metabolism, predator-prey relationships, and the role of biodiversity are major factors underlying the dynamics of food webs and their response to environmental variability. Despite their crucial, complementary and interacting influences, they are usually not considered simultaneously in current marine ecosystem models. In an attempt to fill this gap and determine if these factors and their interaction are sufficient to allow realistic community structure and dynamics to emerge, we formulate a mathematical model of the size-structured dynamics of marine communities which integrates mechanistically individual, population and community levels. The model represents the transfer of energy generated in both time and size by an infinite number of interacting fish species spanning from very small to very large species. It is based on standard individual level assumptions of the Dynamic Energy Budget theory (DEB) as well as important ecological processes such as opportunistic size-based predation and competition for food. Resting on the inter-specific body-size scaling relationships of the DEB theory, the diversity of life-history traits (i.e. biodiversity) is explicitly integrated. The stationary solutions of the model as well as the transient solutions arising when environmental signals (e.g. variability of primary production and temperature) propagate through the ecosystem are studied using numerical simulations. It is shown that in the absence of density-dependent feedback processes, the model exhibits unstable oscillations. Density-dependent schooling probability and schooling-dependent predatory and disease mortalities are proposed to be important stabilizing factors allowing stationary solutions to be reached. At the community level, the shape and slope of the obtained quasi-linear stationary spectrum matches well with empirical studies. When oscillations of primary production are simulated, the model predicts that the variability propagates along the
Spontaneous formation of quantized vortices in Bose-Einstein condensates
Weiler, Chad Nathan
Phase transitions abound in the physical world, from the subatomic length scales of quark condensation to the decoupling forces in the early universe. In the Bose-Einstein condensation phase transition, a gas of trapped bosonic atoms is cooled to a critical temperature. Below this temperature, a macroscopic number of atoms suddenly starts to occupy a single quantum state; these atoms comprise the Bose-Einstein condensate (BEC). The dynamics of the BEC phase transition are the focus of this dissertation and the experiments described here have provided new information on the details of BEC formation. New theoretical developments are proving to be valuable tools for describing BEC phase transition dynamics and interpreting new experimental results. With their amenability to optical manipulation and probing along with the advent of new microscopic theories, BECs provide an important new avenue for gaining insight into the universal dynamics of phase transitions in general. Spontaneous symmetry breaking in the system's order parameter may be one result of cooling through a phase transition. A potential consequence of this is the spontaneous formation of topological defects, which in a BEC appear as vortices. We experimentally observed and characterized the spontaneous formation of vortices during BEC growth. We attribute vortex creation to coherence length limitations during the initial stages of the phase transition. Parallel to these experimental observations, theory collaborators have used the Stochastic Gross-Pitaevski Equation formalism to simulate the growth of a condensate from a thermal cloud. The experimental and theoretical statistical results of the spontaneous formation of vortex cores during the growth of the condensate are in good quantitative agreement with one another, supporting our understanding of the dynamics of the phase transition. We believe that our results are also qualitatively consistent with the Kibble-Zurek mechanism, a universal model for
Bio-oil fractionation and condensation
Brown, Robert C; Jones, Samuel T; Pollard, Anthony
2013-07-02
A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.
The physics of exciton-polariton condensates
Lagoudakis, Konstantinos
2013-01-01
In 2006 researchers created the first polariton Bose-Einstein condensate at 19K in the solid state. Being inherently open quantum systems, polariton condensates open a window into the unpredictable world of physics beyond the “fifth state of matter”: the limited lifetime of polaritons renders polariton condensates out-of-equilibrium and provides a fertile test-bed for non-equilibrium physics. This book presents an experimental investigation into exciting features arising from this non-equilibrium behavior. Through careful experimentation, the author demonstrates the ability of polaritons to synchronize and create a single energy delocalized condensate. Under certain disorder and excitation conditions the complete opposite case of coexisting spatially overlapping condensates may be observed. The author provides the first demonstration of quantized vortices in polariton condensates and the first observation of fractional vortices with full phase and amplitude characterization. Finally, this book investigate...
Condensed phase decomposition and gas phase combustion of hydrazinium nitroformate
Dragomir, O.E.; Tummers, M.J.; Veen, E.H. van; Heijden, A.E.D.M. van der; Roekaerts, D.J.E.M.
2009-01-01
This paper presents the results of a series of experiments on the condensed phase decomposition and the gas phase combustion of hydrazinium nitroformate (HNF). The experiments include SEM analysis of quenched samples that showed evidence of the formation of a foam layer. FTIR spectrometry and mass
Boronic acids facilitate rapid oxime condensations at neutral pH
Schmidt, Pascal; Stress, Cedric; Gillingham, Dennis
2015-01-01
We report here the discovery and development of boron-assisted oxime formation as a powerful connective reaction for chemical biology. Oximes proximal to boronic acids form in neutral aqueous buffer with rate constants of more than 104 M−1 s−1, the largest to date for any oxime condensation. Boron's dynamic coordination chemistry confers an adaptability that seems to aid a number of elementary steps in the oxime condensation. In addition to applications in bioconjugation, the emerging importa...
Toth, Laszlo Daniel
2013-05-01
The well-known phenomenon of the formation of a Bose-Einstein condensate (BEC), a striking consequence of the Bose-Einstein statistics, has been traditionally linked to an ensemble of ultra-cold gas molecules. However, classical systems can also exhibit condensation effects; in the field of photonics, for example, signatures of this condensation in the mode dynamics (\\'light condensation\\', LC) have been theoretically investigated and experimentally observed in various types of multimode lasers [1,2 and ref. therein]. © 2013 IEEE.
THE STABILITY OF VAPOR CONDENSATION EQUILIBRIUM
SHIMIN ZHANG
2005-01-01
The system must get across an energy peak of unstable equilibrium during the condensation of pure vapor; as the supersaturated extent of vapor increases and the temperature decreases, the energy peak shortens and vapor condensation becomes easier. The system must get across an energy peak of unstable equilibrium first, and then get into an energy valley of stable equilibrium during the condensation of impure vapor; as the partial pressure of vapor decreases, the energy peak becomes taller, th...
Nonlinear behavior of the radiative condensation instability
International Nuclear Information System (INIS)
McCarthy, D.; Drake, J.F.
1991-01-01
An investigation of the nonlinear behavior of the radiative condensation instability is presented in a simple one-dimensional magnetized plasma. It is shown that the radiative condensation is typically a nonlinear instability---the growth of the instability is stronger once the disturbance reaches finite amplitude. Moreover, classical parallel thermal conduction is insufficient by itself to saturate the instability. Radiative collapse continues until the temperature in the high density condensation falls sufficiently to reduce the radiation rate
Physics of hollow Bose-Einstein condensates
Padavić, Karmela; Sun, Kuei; Lannert, Courtney; Vishveshwara, Smitha
2016-01-01
Bose-Einstein condensate shells, while occurring in ultracold systems of coexisting phases and potentially within neutron stars, have yet to be realized in isolation on Earth due to the experimental challenge of overcoming gravitational sag. Motivated by the expected realization of hollow condensates by the space-based Cold Atomic Laboratory in microgravity conditions, we study a spherical condensate undergoing a topological change from a filled sphere to a hollow shell. We argue that the col...
Energy Technology Data Exchange (ETDEWEB)
Blocklet, D. [Hopital Universitaire Erasme, Univ. Libre de Bruxelles (Belgium); Martin, P. [Hopital Universitaire Brugmann, Univ. Libre de Bruxelles (Belgium); Schoutens, A. [Hopital Universitaire Erasme, Univ. Libre de Bruxelles (Belgium); Verhas, M. [Hopital Universitaire Brugmann, Univ. Libre de Bruxelles (Belgium); Hooghe, L. [Hopital Universitaire Brugmann, Univ. Libre de Bruxelles (Belgium); Kinnaert, P. [Hopital Universitaire Erasme, Univ. Libre de Bruxelles (Belgium)
1997-01-01
The aims of this study were to determine which of the analytical techniques described for this method time-activity curves analysis of dynamic structures corresponds best with surgical findings, and to ascertain the potential overall contribution of presurgical scintigraphy. 55P patients were studied, 34 of whom presented with primary hyperparathyroidism (HPT) and 21 with secondary HPT. After a 925 MBq injection of technetium-99m MIBI, a 40-min dynamic acquisition was performed and static images were acquired at 5, 20, 40 and 120 min using a gamma camera equipped with a pinhole collimator. Sensitivity was 84.4%, 74% and 65% in adenoma and 76%, 66.6% and 45% in hyperplasia for 15`-120`, FADS and TACs, respectively. Surgical accuracy was 72%, 56% and 59% in adenoma and 53%, 30% and 22% in hyperplasia for 15`-120`, FADS and TACs, respectively. The visual comparison method scored best in all cases. FADS was found to be sensitive in cases of adenoma but was handicapped by more false-positive localizations. TACs were particular inefficient in hyperplasia. With respect to the detection of adenomas, we found a relationship between the gland weight and scintigraphic positivity. This dependence was not found in hyperplasia. The poorer results obtained with all techniques for surgical accuracy can be explained by the need for a complete scintigraphic description of all pathological glands found by the surgeon in a patient. This study demonstrates that the 15`-120` visual comparison method is more efficient However, it was less efficient than neck exploration by an experienced surgeon. (orig./ vhe) (orig.). With 4 figs., 4 tabs.
Dissipation-Managed Bright Soliton in a 1D Bose-Einstein Condensate in an Optical-Lattice Potential
International Nuclear Information System (INIS)
Zhou Zheng; Yu Huiyou; Ao Shengmei; Yan Jiaren
2010-01-01
We study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-one-dimensional Bose-Einstein condensate by including an imaginary three-body recombination loss term and an imaginary linear feeding one in the Gross-Pitaevskii equation, trapped in a shallow optical-lattice potential. Based on the direct approach of perturbation theory for the nonlinear Schroedinger equation, we demonstrate that the height (as well as width) of bright soliton may have little change through selecting experimental parameters. (general)
Vortex-vortex interactions in toroidally trapped Bose-Einstein condensates
Schulte, T.; Santos, L.; Sanpera, A.; Lewenstein, M.
2002-01-01
We analyze the vortex dynamics and vortex-vortex interactions in Bose-Einstein condensates confined in toroidal traps. We show that this particular geometry strongly distorts the vortex dynamics. The numerically calculated vortex trajectories are well explained by an analytical calculation based on image method and conformal mapping. Finally, the dissipation effects are discussed.
Out of equilibrium phase transitions and a toy model for disoriented chiral condensates
International Nuclear Information System (INIS)
Bedaque, P.F.; Das, A.
1993-07-01
We study the dynamics of a second order phase transition in a situation that mimics a sudden quench to a temperature below the critical temperature in a model with dynamical symmetry breaking. In particular we show that the domains of correlated values of the condensate grow as √t and that this result seems to be largely model independent. (author). 9 refs
Advances in modelling of condensation phenomena
Energy Technology Data Exchange (ETDEWEB)
Liu, W.S.; Zaltsgendler, E. [Ontario Hydro Nuclear, Toronto (Canada); Hanna, B. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)
1997-07-01
The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described.
Strangeness condensation and ''clearing'' of the vacuum
International Nuclear Information System (INIS)
Brown, G.E.; Kubodera, Kuniharu; Rho, M.; State Univ. of New York, Stony Brook
1987-01-01
We show that a substantial amount of strange quark-antiquark pair condensates in the nucleon required by the πN sigma term implies that kaons could condense in nuclear matter at a density about three times that of normal nuclear matter. This phenomenon can be understood as the ''cleansing'' of qanti q condensates from the QCD vacuum by a dense nuclear matter, resulting in a (partial) restoration of the chiral symmetry explicitly broken in the vacuum. It is suggested that the condensation signals a new phase distinct from that of quark plasma and that of ordinary dense hadronic matter. (orig.)
Kinetic Isotopic Fractionation of Cd and Zn During Condensation
Cloquet, C.; Carignan, J.; Libourel, G.
2005-12-01
The development of MC-ICPMS allowed to measure precisely isotopic compositions of transitional metals with a resolution generally better than +/- 0.15 per mil per atomic mass unit. The isotopic composition of such metals (Zn, Cd, Cu) varies in terrestrial and extra-terrestrial samples resulting most probably from phase transformations (solid-gas-solid) and/or biogenic fractionation. Up to now, very few experiments were conducted in order to document isotope fractionation during evaporation and condensation of metals. In this study, we report Cd and Zn elemental and isotopic variations measured in fly ashes collected from an urban waste combustor (UWC) equipped with various ash and flue gas filtration devices, including a heat transfer system. In the evacuation system, temperature drop from ca. 900 to 250 degree Celsius. This temperature range allows the evaporation and then condensation of Cd and Zn and probably fusion and oxido-reduction reactions. Indeed, the composition of combustion residues clearly indicates that most of the cadmium and part of the zinc were evacuated in the flue gases. Chemical analysis of the fly ashes collected along the thermal gradient suggest a massive condensation of semi-volatile elements such as Cd and Zn just above the heat transfer plate, which behave as a cold point in the evacuation system. As a first approximation, Cd and Zn contents are directly related to the amount metal condensates on more refractory particles. Leaching experiments on different fly ashes thermodynamic calculations confirmed the occurrence of soluble Cd and Zn salt condensates. The cadmium and Zn isotopic composition of bulk, leachate and residue samples provided variations as large as 1 per mil for delta 114Cd (114Cd/110Cd ratio) and up to 0.5 per mil for delta 66Zn (66Zn/64Zn ratio). Both Cd and Zn delta values are positively correlated to concentrations. According to the position of samples in the thermal gradient of the evacuation system, we suggest that
PAC Spectrometer for Condensed Matter Investigation
Brudanin, V B; Kochetov, O I; Korolev, N A; Milanov, M; Ostrovsky, I V; Pavlov, V N; Salamatin, A V; Timkin, V V; Velichkov, A I; Fomicheva, L N; Tsvyaschenko, A V; Akselrod, Z Z
2005-01-01
A four-detector spectrometer of perturbed angular $\\gamma \\gamma $ correlations is developed for investigation of hyperfine interactions in condensed matter. It allows measurements with practically any types of detectors. A unique circuit design involving a specially developed Master PAC unit combined with a computer allows a substantially higher efficiency, reduced setup time and simpler operation in comparison with traditional PAC spectrometers. A cryostat and a high-temperature oven allow measurements in the temperature range from 120 to 1300 K. An encased electromagnet makes it possible to generate a magnetic field up to 2 T on a sample. The measurement system includes a press with a specially designed high-pressure chamber allowing on-line PAC measurements in samples under pressure up to 60 GPa.
Fragmented-condensate solid of dipolar excitons
Andreev, S. V.
2017-05-01
We discuss a possible link between the recently observed macroscopic ordering of ultracold dipolar excitons (MOES) and the phenomenon of supersolidity. In the dilute limit we predict a stable supersolid state for a quasi-one-dimensional system of bosonic dipoles characterized by two- and three-body contact repulsion. We phenomenologically extend our theory to the strongly-correlated regime and find a critical value of the contact interaction parameter at which the supersolid exhibits a quantum phase transition to a fragmented state. The wavelength of the fragmented-condensate solid is defined by the balance between the quantum pressure and the entropy due to fluctuations of the relative phases between the fragments. Our model appears to be in good agreement with the relevant experimental data, including the very recent results on commensurability effect and wavelength of the MOES.
Atomic lattice excitons: from condensates to crystals
International Nuclear Information System (INIS)
Kantian, A; Daley, A J; Toermae, P; Zoller, P
2007-01-01
We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed by fermionic atoms in two bands of an optical lattice. Such a system provides a clean set-up, with tunable masses and interactions, to study fundamental properties of excitons including exciton condensation. We also find that for a large effective mass ratio between particles and holes, effective long-range interactions can mediate the formation of an exciton crystal, for which superfluidity is suppressed. Using a combination of mean-field treatments, bosonized theory based on a Born-Oppenheimer approximation, and one-dimensional (1D) numerical computation, we discuss the properties of ALEs under varying conditions, and discuss in particular their preparation and measurement
Atomic lattice excitons: from condensates to crystals
Energy Technology Data Exchange (ETDEWEB)
Kantian, A [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Daley, A J [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria); Toermae, P [Nanoscience Center, Department of Physics, University of Jyvaeskylae, PO Box 35, FIN-40014 (Finland); Zoller, P [Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences, A-6020 Innsbruck (Austria)
2007-11-15
We discuss atomic lattice excitons (ALEs), bound particle-hole pairs formed by fermionic atoms in two bands of an optical lattice. Such a system provides a clean set-up, with tunable masses and interactions, to study fundamental properties of excitons including exciton condensation. We also find that for a large effective mass ratio between particles and holes, effective long-range interactions can mediate the formation of an exciton crystal, for which superfluidity is suppressed. Using a combination of mean-field treatments, bosonized theory based on a Born-Oppenheimer approximation, and one-dimensional (1D) numerical computation, we discuss the properties of ALEs under varying conditions, and discuss in particular their preparation and measurement.
EPA's Environmental Technology Verification Program has tested New Condensator Inc.'s Condensator Diesel Engine Retrofit Crankcase Ventilation System. Brake specific fuel consumption (BSFC), the ratio of engine fuel consumption to the engine power output, was evaluated for engine...
Sakurai-Yageta, Mika; Maruyama, Tomoko; Suzuki, Takashi; Ichikawa, Kazuhisa; Murakami, Yoshinori
2015-01-01
Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation. PMID:25780926
Sakurai-Yageta, Mika; Maruyama, Tomoko; Suzuki, Takashi; Ichikawa, Kazuhisa; Murakami, Yoshinori
2015-01-01
Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10 min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation.
Elucidation of polymer induced DNA condensation. Visualisation at the single molecular level
International Nuclear Information System (INIS)
Martin, Alison Laura
2002-01-01
formation, this question has been addressed in two ways. Firstly, in an attempt to form intermediates of the condensation process, DNA has been exposed to cationic moieties over a range of cationic charge to DNA nucleotide ratios. The morphologies of the resulting complexes have been analysed, and hypotheses have been constructed, regarding the mechanisms of DNA condensate formation. The second methodology adopted involved the visualisation of the formation of DNA condensates in real time. DNA-cation complexes have been visualised in a near in situ environment, allowing dynamic tertiary conformational change of individual DNA condensates to be observed. The investigations presented here are among the first to utilise atomic force microscopy, operating in an aqueous environment, to elucidate DNA condensate morphology and dynamic conformational change in real time, and to apply atomic force microscopy in the characterisation of potential gene delivery vectors. (author)
Birbarah, Patrick; Li, Zhaoer; Pauls, Alexander; Miljkovic, Nenad
2015-07-21
Superhydrophobic micro/nanostructured surfaces for dropwise condensation have recently received significant attention due to their potential to enhance heat transfer performance by shedding positively charged water droplets via coalescence-induced droplet jumping at length scales below the capillary length and allowing the use of external electric fields to enhance droplet removal and heat transfer, in what has been termed electric-field-enhanced (EFE) jumping-droplet condensation. However, achieving optimal EFE conditions for enhanced heat transfer requires capturing the details of transport processes that is currently lacking. While a comprehensive model has been developed for condensation on micro/nanostructured surfaces, it cannot be applied for EFE condensation due to the dynamic droplet-vapor-electric field interactions. In this work, we developed a comprehensive physical model for EFE condensation on superhydrophobic surfaces by incorporating individual droplet motion, electrode geometry, jumping frequency, field strength, and condensate vapor-flow dynamics. As a first step toward our model, we simulated jumping droplet motion with no external electric field and validated our theoretical droplet trajectories to experimentally obtained trajectories, showing excellent temporal and spatial agreement. We then incorporated the external electric field into our model and considered the effects of jumping droplet size, electrode size and geometry, condensation heat flux, and droplet jumping direction. Our model suggests that smaller jumping droplet sizes and condensation heat fluxes require less work input to be removed by the external fields. Furthermore, the results suggest that EFE electrodes can be optimized such that the work input is minimized depending on the condensation heat flux. To analyze overall efficiency, we defined an incremental coefficient of performance and showed that it is very high (∼10(6)) for EFE condensation. We finally proposed mechanisms
Quasiparticles in condensed matter systems
Wölfle, Peter
2018-03-01
Quasiparticles are a powerful concept of condensed matter quantum theory. In this review, the appearence and the properties of quasiparticles are presented in a unifying perspective. The principles behind the existence of quasiparticle excitations in both quantum disordered and ordered phases of fermionic and bosonic systems are discussed. The lifetime of quasiparticles is considered in particular near a continuous classical or quantum phase transition, when the nature of quasiparticles on both sides of a transition into an ordered state changes. A new concept of critical quasiparticles near a quantum critical point is introduced, and applied to quantum phase transitions in heavy fermion metals. Fractional quasiparticles in systems of restricted dimensionality are reviewed. Dirac quasiparticles emerging in so-called Dirac materials are discussed. The more recent discoveries of topologically protected chiral quasiparticles in topological matter and Majorana quasiparticles in topological superconductors are briefly reviewed.
Imamoto, Takuya; Endoh, Tetsuo
2014-01-01
The scalability study and the impact of the self-heating effect (SHE) on memory operation of the bulk vertical-channel field effect diode (FED) type capacitorless one transistor (1T) dynamic random access memory (DRAM) cell are investigated via device simulator for the first time. The vertical-channel FED type 1T-DRAM cell shows the excellent hold characteristics (100 ms at 358 K of ambient temperature) with large enough read current margin (1 µA/cell) even when silicon pillar diameter (D) is scaled down from 20 to 12 nm. It is also shown that by employing the vertical-channel FED type, maximum lattice temperature in the memory cell due to SHE (T_{\\text{L}}^{\\text{Max}}) can be suppressed to a negligible small value and only reach 300.6 from 300 K ambient temperature due to the low lateral electric field, while the vertical-channel bipolar junction transistor (BJT) type 1T-DRAM shows significant SHE (T_{\\text{L}}^{\\text{Max}} = 330.6 K). Moreover, this excellent thermal characteristic can be maintained even when D is scaled down from 20 to 12 nm.
Directory of Open Access Journals (Sweden)
Woochul Nam
Full Text Available Kinesins are molecular motors which walk along microtubules by moving their heads to different binding sites. The motion of kinesin is realized by a conformational change in the structure of the kinesin molecule and by a diffusion of one of its two heads. In this study, a novel model is developed to account for the 2D diffusion of kinesin heads to several neighboring binding sites (near the surface of microtubules. To determine the direction of the next step of a kinesin molecule, this model considers the extension in the neck linkers of kinesin and the dynamic behavior of the coiled-coil structure of the kinesin neck. Also, the mechanical interference between kinesins and obstacles anchored on the microtubules is characterized. The model predicts that both the kinesin velocity and run length (i.e., the walking distance before detaching from the microtubule are reduced by static obstacles. The run length is decreased more significantly by static obstacles than the velocity. Moreover, our model is able to predict the motion of kinesin when other (several motors also move along the same microtubule. Furthermore, it suggests that the effect of mechanical interaction/interference between motors is much weaker than the effect of static obstacles. Our newly developed model can be used to address unanswered questions regarding degraded transport caused by the presence of excessive tau proteins on microtubules.
Possibility of removing condensate and scattered oil from gas-condensate field during bed flooding
Energy Technology Data Exchange (ETDEWEB)
Belkina, N.A.; Yagubov, M.S.
1984-01-01
The problem is set of evaluating the possible removal from the bed of scattered oil and condensate during flooding of the bed. For this purpose, an experimental study was made of the displacement by water from the porous medium of the oil and condensate saturating it. The obtained experimental results permit evaluation of the possible removal from the gas-condensate bed of scattered oil and condensate during flooding of the bed.
Accident localization system with jet condensers for VVER 440-V 230 NPP at Jaslovske Bohunice
International Nuclear Information System (INIS)
Murani, J.
1995-01-01
The operational safety of the V1 nuclear power plant (NPP) is unsatisfactory and does not correspond to present requirements as to nuclear safety. Further NPP operation after 1995 is conditional on nuclear safety enhancement to a level comparable with that in West European countries. This aim should be achieved by a principal reconstruction involving in addition to others also backfitting the V1 NPP with technical facilities aimed at coping with a design basis accident (DBA).To cope with such an accident the Power Equipment Research Institute (VUEZ) designed an accident localization system with jet condensers. This system consists of (a) an air trap (one for each unit, mutually interconnected) with an expansion bell enclosed within, placed on a plate with 200 pipes of jet condensers passing through, and (b) a connecting duct between the hermetic zone and the air trap. The vertical jet condenser is an essential element of the system designed for steam condensation. Apart from condensation it serves as a water seal separating units 1 and 2.Demonstration tests of the jet condenser (model 1:1) condensing function were carried out at the testing unit of the All-Union Research Institute for NPP Operation (VNIIAES), Moscow in Kashir, 11-22 September 1992. These experiments proved the jet condenser ability to ensure complete condensation of the steam produced. Experimental verification of the sealing function (model 1:1) was carried out at the testing unit of the VUEZ Tlmace. These experiments concerning the dynamics and overpressure in the free space above the pool were close to the conditions in the air trap during DBA. The jet condenser height was proved to be sufficient to ensure the sealing function. Design and experimental work has been implemented in close cooperation with Russian experts Mr. V.N. Bulynin from the VNIIAES, Moscow, and Mr. M.V. Kuznecov from the Scientific and Engineering Center for Nuclear and Radiological Safety, Moscow. (orig.)
Thermalization and Bose-Einstein Condensation in Overpopulated Glasma
Energy Technology Data Exchange (ETDEWEB)
Blaizot, Jean-Paul; Gelis, François [Institut de Physique Théorique (URA 2306 du CNRS), CEA/DSM/Saclay, 91191, Gif-sur-Yvette Cedex (France); Liao, Jinfeng [Physics Department and CEEM, Indiana University, 2401 N Milo B. Sampson Lane, Bloomington, IN 47408 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); McLerran, Larry [Physics Department, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); RIKEN BNL Research Center, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States); Venugopalan, Raju [Physics Department, Bldg. 510A, Brookhaven National Laboratory, Upton, NY 11973 (United States)
2013-05-02
We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the far-from-equilibrium gluonic matter (“Glasma”) is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an emergent property of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop a kinetic approach for describing its evolution toward thermalization as well as the onset of condensation.
Thermalization and Bose-Einstein Condensation in Overpopulated Glasma
International Nuclear Information System (INIS)
Blaizot, Jean-Paul; Gelis, François; Liao, Jinfeng; McLerran, Larry; Venugopalan, Raju
2013-01-01
We report recent progress on understanding the thermalization of the quark-gluon plasma during the early stage in a heavy ion collision. The initially high overpopulation in the far-from-equilibrium gluonic matter (“Glasma”) is shown to play a crucial role. The strongly interacting nature (and thus fast evolution) naturally arises as an emergent property of this pre-equilibrium matter where the intrinsic coupling is weak but the highly occupied gluon states coherently amplify the scattering. A possible transient Bose-Einstein Condensate is argued to form dynamically on a rather general ground. We develop a kinetic approach for describing its evolution toward thermalization as well as the onset of condensation
Fuller, Robert G., Ed.; And Others
This is part of a series of 42 Calculus Based Physics (CBP) modules totaling about 1,000 pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized course in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…
DEFF Research Database (Denmark)
Lindblom, Erik Ulfson; Press-Kristensen, Kåre; Vanrolleghem, P.A.
2009-01-01
with the endocrine disrupting XOC bisphenol-A (BPA) in an activated sludge process with real wastewater were used to hypothesize an ASM-based process model including aerobic growth of a specific BPA-degrading microorganism and sorption of BPA to sludge. A parameter estimation method was developed, which...
Connections between quantum chromodynamics and condensed ...
Indian Academy of Sciences (India)
Abstract. Features of QCD can be seen qualitatively in certain condensed matter systems. Recently some of the analyses that originated in condensed matter physics have found applications in QCD. Using examples we discuss some of the connections between the two fields and show how progress can be made by ...
Collision of Bose Condensate Dark Matter structures
International Nuclear Information System (INIS)
Guzman, F. S.
2008-01-01
The status of the scalar field or Bose condensate dark matter model is presented. Results about the solitonic behavior in collision of structures is presented as a possible explanation to the recent-possibly-solitonic behavior in the bullet cluster merger. Some estimates about the possibility to simulate the bullet cluster under the Bose Condensate dark matter model are indicated.
Effective thermal conductivity of condensed polymeric nanofluids ...
Indian Academy of Sciences (India)
Thermal properties of polymeric nanosolids, obtained by condensing the corresponding nanofluids, are investigated using photothermal techniques. The heat transport properties of two sets of polyvinyl alcohol (PVA) based nanosolids, TiO2/PVA and Cu/PVA, prepared by condensing the respective nanofluids, which are ...
Quantum monodromy in trapped Bose condensates
Waalkens, H.
2002-01-01
Bose-Einstein condensation of ultra cold atoms is typically realized in magnetic traps which effectively lead to an axially symmetric harmonic potential. This letter shows that the spectrum of collective vibrational modes of a repulsive condensate in a prolate potential displays a defect known as
Born-Kothari Condensation for Fermions
Directory of Open Access Journals (Sweden)
Arnab Ghosh
2017-09-01
Full Text Available In the spirit of Bose–Einstein condensation, we present a detailed account of the statistical description of the condensation phenomena for a Fermi–Dirac gas following the works of Born and Kothari. For bosons, while the condensed phase below a certain critical temperature, permits macroscopic occupation at the lowest energy single particle state, for fermions, due to Pauli exclusion principle, the condensed phase occurs only in the form of a single occupancy dense modes at the highest energy state. In spite of these rudimentary differences, our recent findings [Ghosh and Ray, 2017] identify the foregoing phenomenon as condensation-like coherence among fermions in an analogous way to Bose–Einstein condensate which is collectively described by a coherent matter wave. To reach the above conclusion, we employ the close relationship between the statistical methods of bosonic and fermionic fields pioneered by Cahill and Glauber. In addition to our previous results, we described in this mini-review that the highest momentum (energy for individual fermions, prerequisite for the condensation process, can be specified in terms of the natural length and energy scales of the problem. The existence of such condensed phases, which are of obvious significance in the context of elementary particles, have also been scrutinized.
Dropwise Condensation Enhancement on Geometric Features
Zhao, Yajing; Preston, Daniel J.; Lu, Zhengmao; Wang, Evelyn N.
Dropwise condensation, which has been demonstrated to exhibit a 5-7X higher heat transfer coefficient compared with state-of-the-art filmwise condensation, contributes to energy savings in a wide range of applications such as desalination systems, steam cycles and dew harvesting. In order to enhance dropwise condensation performance, previous studies have investigated the effects of surface geometric features on droplet growth rates and found that bumps protruding from surfaces can effectively promote dropwise condensation. In this work, we show that while bumps on surfaces enable droplets to grow faster in some cases, there are also cases where bumps on surfaces actually degrade dropwise condensation. We numerically simulated and experimentally demonstrated that even the same surface geometric feature can exert completely opposite effects on dropwise condensation of water under two different working conditions (pure vapor vs. air vapor mixture). This phenomenon is explained by comparing the heat and mass transfer resistance of the surface structure to that of the vapor transport during dropwise condensation. We expect that the fundamental understanding developed in this study will provide useful guidelines for relevant condensation applications.
Legenbauer, Tanja; Vocks, Silja; Betz, Sabrina; Puigcerver, Maria Jose Baguena; Benecke, Andrea; Troje, Nikolaus F.; Ruddel, Heinz
2011-01-01
Various components of body image were measured to assess body image disturbances in patients with obesity. To overcome limitations of previous studies, a photo distortion technique and a biological motion distortion device were included to assess static and dynamic aspects of body image. Questionnaires assessed cognitive-affective aspects, bodily…
Perspective: chemical dynamics simulations of non-statistical reaction dynamics.
Ma, Xinyou; Hase, William L
2017-04-28
Non-statistical chemical dynamics are exemplified by disagreements with the transition state (TS), RRKM and phase space theories of chemical kinetics and dynamics. The intrinsic reaction coordinate (IRC) is often used for the former two theories, and non-statistical dynamics arising from non-IRC dynamics are often important. In this perspective, non-statistical dynamics are discussed for chemical reactions, with results primarily obtained from chemical dynamics simulations and to a lesser extent from experiment. The non-statistical dynamical properties discussed are: post-TS dynamics, including potential energy surface bifurcations, product energy partitioning in unimolecular dissociation and avoiding exit-channel potential energy minima; non-RRKM unimolecular decomposition; non-IRC dynamics; direct mechanisms for bimolecular reactions with pre- and/or post-reaction potential energy minima; non-TS theory barrier recrossings; and roaming dynamics.This article is part of the themed issue 'Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces'. © 2017 The Author(s).
Assessment of the controllability of condensible emissions. Final report
Energy Technology Data Exchange (ETDEWEB)
Shareef, G.S.; Waddell, J.T.
1990-10-01
The report gives results of a study to gain insights into the condensible emissions area from an air toxics perspective, with emphasis on controllability and chemical composition of these emissions. The study: compiled existing data on condensible emissions; determined the chemical composition of condensible emissions, where possible; identified source categories that are major emitters of condensibles; evaluated the effectiveness of various control devices in reducing condensible emissions; and evaluated how the performance of currently available control technologies can be improved to better control condensible emissions. Two data bases were developed: the Condensibles Data Base contains 43 emission source categories; the Specialized Condensibles Data Base focuses on the chemical composition of condensible emissions.
Organic Aerosols as Cloud Condensation Nuclei
Hudson, J. G.
2002-05-01
The large organic component of the atmospheric aerosol contributes to both natural and anthropogenic cloud condensation nuclei (CCN). Moreover, some organic substances may reduce droplet surface tension (Facchini et al. 1999), while others may be partially soluble (Laaksonen et al. 1998), and others may inhibit water condensation. The interaction of organics with water need to be understood in order to better understand the indirect aerosol effect. Therefore, laboratory CCN spectral measurements of organic aerosols are presented. These are measurements of the critical supersaturation (Sc), the supersaturation needed to produce an activated cloud droplet, as a function of the size of the organic particles. Substances include sodium lauryl (dodecyl) sulfate, oxalic, adipic, pinonic, hexadecanedioic, glutaric, stearic, succinic, phthalic, and benzoic acids. These size-Sc relationships are compared with theoretical and measured size-Sc relationships of common inorganic compounds (e.g., NaCl, KI, ammonium and calcium sulfate). Unlike most inorganics some organics display variations in solubility per unit mass as a function of particle size. Those showing relatively greater solubility at smaller sizes may be attributable to surface tension reduction, which is greater for less water dilution, as is the case for smaller particles, which are less diluted at the critical sizes. This was the case for sodium dodecyl sulfate, which does reduce surface tension. Relatively greater solubility for larger particles may be caused by greater dissolution at the higher dilutions that occur with larger particles; this is partial solubility. Measurements are also presented of internal mixtures of various organic and inorganic substances. These measurements were done with two CCN spectrometers (Hudson 1989) operating simultaneously. These two instruments usually displayed similar results in spite of the fact that they have different flow rates and supersaturation profiles. The degree of
Capillary Condensation in 8 nm Deep Channels.
Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David
2018-02-01
Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.
International Nuclear Information System (INIS)
Shooshtari, S.H. Rajaee; Shahsavand, A.
2017-01-01
Natural gases provide around a quarter of energy consumptions around the globe. Supersonic separators (3S) play multifaceted role in natural gas industry processing, especially for water and hydrocarbon dew point corrections. These states of the art devices have minimum energy requirement and favorable process economy compared to conventional facilities. Their relatively large pressure drops may limit their application in some situations. To maximize the energy recovery of the dew point correction facility, the pressure loss across the 3S unit should be minimized. The optimal structure of 3s unit (including shock wave location and diffuser angle) is selected using simultaneous combination of normal shock occurrence and condensation in the presence of nucleation and growth processes. The condense-free gas enters the non-isentropic normal shock wave. The simulation results indicate that the normal shock location, pressure recovery coefficient and onset position strongly vary up to a certain diffuser angle (β = 8°) with the maximum pressure recovery of 0.88 which leads to minimum potential energy loss. Computational fluid dynamic simulations show that separation of boundary layer does not happen for the computed optimal value of β and it is essentially constant when the inlet gas temperatures and pressures vary over a relatively broad range. - Highlights: • Supersonic separators have found numerous applications in oil and gas industries. • Maximum pressure recovery is crucial for such units to maximize energy efficiency. • Simultaneous condensation and shock wave occurrence are studied for the first time. • Diverging nozzle angle of 8° can provide maximum pressure recovery of 0.88. • The optimal diffuser angle remains constant over a broad range of inlet conditions.
Lagrangian condensation microphysics with Twomey CCN activation
Grabowski, Wojciech W.; Dziekan, Piotr; Pawlowska, Hanna
2018-01-01
We report the development of a novel Lagrangian microphysics methodology for simulations of warm ice-free clouds. The approach applies the traditional Eulerian method for the momentum and continuous thermodynamic fields such as the temperature and water vapor mixing ratio, and uses Lagrangian super-droplets to represent condensed phase such as cloud droplets and drizzle or rain drops. In other applications of the Lagrangian warm-rain microphysics, the super-droplets outside clouds represent unactivated cloud condensation nuclei (CCN) that become activated upon entering a cloud and can further grow through diffusional and collisional processes. The original methodology allows for the detailed study of not only effects of CCN on cloud microphysics and dynamics, but also CCN processing by a cloud. However, when cloud processing is not of interest, a simpler and computationally more efficient approach can be used with super-droplets forming only when CCN is activated and no super-droplet existing outside a cloud. This is possible by applying the Twomey activation scheme where the local supersaturation dictates the concentration of cloud droplets that need to be present inside a cloudy volume, as typically used in Eulerian bin microphysics schemes. Since a cloud volume is a small fraction of the computational domain volume, the Twomey super-droplets provide significant computational advantage when compared to the original super-droplet methodology. Additional advantage comes from significantly longer time steps that can be used when modeling of CCN deliquescence is avoided. Moreover, other formulation of the droplet activation can be applied in case of low vertical resolution of the host model, for instance, linking the concentration of activated cloud droplets to the local updraft speed. This paper discusses the development and testing of the Twomey super-droplet methodology, focusing on the activation and diffusional growth. Details of the activation implementation
Condensing boiler applications in the process industry
International Nuclear Information System (INIS)
Chen, Qun; Finney, Karen; Li, Hanning; Zhang, Xiaohui; Zhou, Jue; Sharifi, Vida; Swithenbank, Jim
2012-01-01
Major challenging issues such as climate change, energy prices and fuel security have focussed the attention of process industries on their energy efficiency and opportunities for improvement. The main objective of this research study was to investigate technologies needed to exploit the large amount of low grade heat available from a flue gas condensing system through industrial condensing boilers. The technology and application of industrial condensing boilers in various heating systems were extensively reviewed. As the condensers require site-specific engineering design, a case study was carried out to investigate the feasibility (technically and economically) of applying condensing boilers in a large scale district heating system (40 MW). The study showed that by recovering the latent heat of water vapour in the flue gas through condensing boilers, the whole heating system could achieve significantly higher efficiency levels than conventional boilers. In addition to waste heat recovery, condensing boilers can also be optimised for emission abatement, especially for particle removal. Two technical barriers for the condensing boiler application are corrosion and return water temperatures. Highly corrosion-resistant material is required for condensing boiler manufacture. The thermal design of a 'case study' single pass shell-and-tube condensing heat exchanger/condenser showed that a considerable amount of thermal resistance was on the shell-side. Based on the case study calculations, approximately 4900 m 2 of total heat transfer area was required, if stainless steel was used as a construction material. If the heat transfer area was made of carbon steel, then polypropylene could be used as the corrosion-resistant coating material outside the tubes. The addition of polypropylene coating increased the tube wall thermal resistance, hence the required heat transfer area was approximately 5800 m 2 . Net Present Value (NPV) calculations showed that the choice of a carbon
2008 Summer Research Institute Interfacial and Condensed Phase Chemical Physics Annual Report
Energy Technology Data Exchange (ETDEWEB)
Garrett, Bruce C.; Tonkyn, Russell G.; Avery, Nachael B.
2008-11-01
For the fifth year, the Pacific Northwest National Laboratory in Richland, Washington, invited graduate students, postdoctoral fellows, university faculty, and students entering graduate students from around the world to participate in the Summer Research Institute in Interfacial and Condensed Phase Chemical Physics. The institute offers participants the opportunity to gain hands-on experience in top-notch research laboratories while working along internationally respected mentors. Of the 38 applicants, 20 were accepted for the 8- to 10-week program. The participants came from universities as close as Seattle and Portland and as far away as Germany and Singapore. At Pacific Northwest National Laboratory, the 20 participants were mentored by 13 scientists. These mentors help tailor the participant’s experience to the needs of that person. Further, the mentors provide guidance on experimental and theoretical techniques, research design and completion, and other aspects of scientific careers in interfacial and condensed phase chemical physics. The research conducted at the institute can result in tangible benefits for the participants. For example, many have co-authored papers that have been published in peer-reviewed journals, including top-rated journals such as Science. Also, they have presented their research at conferences, such as the Gordon Research Conference on Dynamics at Surfaces and the AVS national meeting. Beyond that, many of the participants have started building professional connections with researchers at Pacific Northwest National Laboratory, connections that will serve them well during their careers.
Condensing economizers for small coal-fired boilers and furnaces
Energy Technology Data Exchange (ETDEWEB)
Butcher, T.A.; Litzke, W.
1994-01-01
Condensing economizers increase the thermal efficiency of boilers by recovering sensible and latent heat from exhaust gas. These economizers are currently being used commercially for this purpose in a wide range of applications. Performance is dependent upon application-specific factors affecting the utility of recovered heat. With the addition of a condensing economizer boiler efficiency improvements up to 10% are possible. Condensing economizers can also capture flue gas particulates. In this work, the potential use of condensing economizers for both efficiency improvement and control of particulate emissions from small, coal water slurry-fired boilers was evaluated. Analysis was done to predict heat transfer and particulate capture by mechanisms including: inertial impaction, interception, diffusion, thermophoretic forces, and condensation growth. Shell-and-tube geometries were considered with flue gas on the outside of Teflon-covered tubes. Experimental studies were done with both air- and water-cooled economizers refit to a small boiler. Two experimental arrangements were used including oil-firing with injection of flyash upstream of the economizer and direct coal water slurry firing. Firing rates ranged from 27 to 82 kW (92,000 to 280,000 Btu/hr). Inertial impaction was found to be the most important particulate capture mechanism and removal efficiencies to 95% were achieved. With the addition of water sprays directly on the first row of tubes, removal efficiencies increased to 98%. Use of these sprays adversely affects heat recovery. Primary benefits of the sprays are seen to be the addition of small impaction sites and future design improvements are suggested in which such small impactors are permanently added to the highest velocity regions of the economizer. Predicted effects of these added impactors on particulate removal and pressure drop are presented.
Charged ρ-meson condensation in neutron stars
Kolomeitsev, E. E.; Maslov, K. A.; Voskresensky, D. N.
2018-02-01
We extend relativistic mean-field models with hadron masses and meson-baryon coupling constants dependent on the scalar field σ, including hyperons and Δ (1232) baryons, to incorporate a possibility of the charged ρ meson condensation in neutron star matter. The influence of the ρ- condensation on the equation of state proves to be strongly model dependent. In our models of one type (KVORcut-based ones) the ρ- condensation arises by a second-order phase transition above a critical density and the maximum value of the neutron star mass diminishes only slightly. The matter composition changes more significantly. In our models of other type (MKVOR*-based ones), if the system is considered at fixed density, the ρ- condensation arises by a second-order phase transition at the baryon density n = nc,ρ(II) and at a slightly higher density n = nc,ρ(I) there occurs a first-order phase transition. In a neutron star matter starting with a density n matter composition. Dependence of the results on a choice of the ρ meson scaling functions for the effective ρ meson mass and coupling constants is also investigated.
Nitrogen condensation in Titan's atmosphere under contemporary atmospheric composition
Tokano, Tetsuya
2017-06-01
Temperature profiles of Titan's atmosphere obtained by Cassini radio occultations approach the nitrogen condensation temperature curve at some places. This raises the question as to whether nitrogen, Titan's main atmospheric constituent, might condense in some seasons and areas contrary to previous perception. To address this question, possible areas and seasons of nitrogen condensation are searched for by a global climate model. The model is run under the present atmospheric pressure and composition but under various orbital configurations including the present one. Under the present orbital configuration the polar temperature at either pole becomes lowest around the northern autumnal equinox one season after aphelion. Liquid nitrogen clouds may appear in this season between 30 and 40 km altitude at least near the south pole, presumably embedded in icy methane clouds. Any falling nitrogen rain is likely to entirely evaporate before reaching the surface and thus does not affect the seasonal cycle of surface pressure. Seasonal nitrogen condensation is more frequent and intense when Saturn's orbital eccentricity is larger and hence the heliocentric distance at aphelion is larger. Nevertheless, orbital parameter variations alone are not capable of flooding the surface with liquid nitrogen or causing large fluctuations of the surface pressure.
Vortices in spin-orbit-coupled Bose-Einstein condensates
International Nuclear Information System (INIS)
Radic, J.; Sedrakyan, T. A.; Galitski, V.; Spielman, I. B.
2011-01-01
Realistic methods to create vortices in spin-orbit-coupled Bose-Einstein condensates are discussed. It is shown that, contrary to common intuition, rotation of the trap containing a spin-orbit condensate does not lead to an equilibrium state with static vortex structures but gives rise instead to nonequilibrium behavior described by an intrinsically time-dependent Hamiltonian. We propose here the following alternative methods to induce thermodynamically stable static vortex configurations: (i) to rotate both the lasers and the anisotropic trap and (ii) to impose a synthetic Abelian field on top of synthetic spin-orbit interactions. Effective Hamiltonians for spin-orbit condensates under such perturbations are derived for most currently known realistic laser schemes that induce synthetic spin-orbit couplings. The Gross-Pitaevskii equation is solved for several experimentally relevant regimes. The new interesting effects include spatial separation of left- and right-moving spin-orbit condensates, the appearance of unusual vortex arrangements, and parity effects in vortex nucleation where the topological excitations are predicted to appear in pairs. All these phenomena are shown to be highly nonuniversal and depend strongly on a specific laser scheme and system parameters.
Assessment of ice-condenser containment performance issues
International Nuclear Information System (INIS)
Nourbakhsh, H.P.; Lehner, J.R.; Lane, J.
1990-01-01
Containment performance plays a dominant role in the assessment of risk associated with severe accidents. The primary concerns for containment performance are how well the containment can withstand the pressure and temperature loads associated with severe core damage accidents and whether or not the containment is bypassed. The objective of this paper is to summarize an issue characterization study performed by Brookhaven National Laboratory for an ice-condenser containment during severe accidents. This study was the first to focus in a coordinated way on the challenges and improvements relevant to an ice-condenser containment and provides a comprehensive statement of the relevant issues that can be used in the US Nuclear Regulatory Commission (NRC) staff's evaluation processes and by utilities during their individual plant examinations. The types of pressurized water reactor ice-condenser containment challenges that have been identified in past probabilistic risk assessments, including the second draft of the NUREG-1150 risk analysis for Sequoyah, are summarized and arranged according to the containment function objectives they threaten. A list of proposed potential improvements for an ice-condenser containment is given
Contribution to the study of unsteady condensation in transonic flow
International Nuclear Information System (INIS)
Collignan, B.; Laali, A.R.
1993-12-01
The aim of this thesis is the study of transonic steam flows with condensation, especially at high pressure. This study includes a numerical part an experimental one. The modelling has consisted of introducing a spontaneous condensation model in a one-dimensional Euler code using steam-water thermodynamic tables. Calculations, performed with this code, are in good agreement with experimental results at low pressure. The experimental study has been undertaken on a high pressure experimental loop installed at the Bugey nuclear power plant. We have studied steam flows in nozzles. The results obtained show that a partial heterogeneous condensation occurs in these flows. This proportion is stronger if the expansion rate of the flow is low and if the inlet pressure is high. However, a correction factor is obtained for high pressure nucleation rate model from experimental results. No unsteady condensation has been observed for flows between 15 bars and 50 bars with the steam available at Bugey power plant. (authors). figs., 71 refs., 6 annexes
Condensing embryology teaching: alternative perspectives
Directory of Open Access Journals (Sweden)
Hasan M
2018-03-01
Full Text Available Mohammad Hasan, Syed Maaz Tariq, Syed Ali Haider Department of MBBS, Jinnah Sindh Medical University, Karachi, PakistanWe read the article “Condensing embryology teaching for medical students: can it be taught in 2 hours?” by Kazzazi and Bartlett quite attentively. The authors were successful in mentioning an effective mode of teaching embryology. Embryology is indeed an important subject that forms the base for appreciating anatomy and has immense practical implementations in different parts of medicine, for example, in pediatrics and ENT surgery. However, it is often neglected and is only taught in preclinical years.1 The authors proposed a method for teaching embryology splendidly from their perspective; therefore, we felt the need to expand the discussion from the perspective of third-year medical students who have just completed their preclinical years. Hence, we would like to mention few limitations to this study as well.Authors’ replyFawz Kazzazi, Jonathan Bartlett School of Clinical Medicine, University of Cambridge, Cambridge, UKWe read with interest the response letter by Hasan et al. We must first commend the editor and journal on their great ability to unify the medical community and extend topics for debate internationally.View the original paper by Kazzazi and Bartlett.
Topology and condensed matter physics
Mj, Mahan; Bandyopadhyay, Abhijit
2017-01-01
This book introduces aspects of topology and applications to problems in condensed matter physics. Basic topics in mathematics have been introduced in a form accessible to physicists, and the use of topology in quantum, statistical and solid state physics has been developed with an emphasis on pedagogy. The aim is to bridge the language barrier between physics and mathematics, as well as the different specializations in physics. Pitched at the level of a graduate student of physics, this book does not assume any additional knowledge of mathematics or physics. It is therefore suited for advanced postgraduate students as well. A collection of selected problems will help the reader learn the topics on one's own, and the broad range of topics covered will make the text a valuable resource for practising researchers in the field. The book consists of two parts: one corresponds to developing the necessary mathematics and the other discusses applications to physical problems. The section on mathematics is a qui...
Direct contact condensation in packed beds
Energy Technology Data Exchange (ETDEWEB)
Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)
2006-12-15
A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)
Emergency condensator for BWR type reactor
International Nuclear Information System (INIS)
Ubakai, Yoichi; Narumi, Yuichi; Sakata, Yuji.
1992-01-01
An emergency condensator is constituted with heat transfer pipes, a steam chamber, an upper pipe plate, a lower pipe plate and a condensate chamber. The upper pipe plate is secured by supports, and a steam pipe is connected to the upper pipe plate. A condensate pipeline and a incondensible gas vent pipe are disposed to the condensate chamber. Taking thermal expansion of the steam pipes and thermal expansion of the heat transfer pipes into consideration, the heat transfer pipe is made as an L-shaped pipe having a vertical portion and a horizontal portion so as to absorb each of the thermal expansion smoothly. The L-shaped heat transfer pipes are constituted as a bundle of pipes having the end portions thereof secured to the upper pipe plate and the lower pipe plate. The emergency condensator is disposed in a emergency condensator pool chamber. Cooling water in contact with the outer side of the L-shaped heat transfer pipes is the pool water in the pool chamber, and the condensator chamber is disposed in concrete walls of the pool chamber. With such a constitution, stress due to thermal expansion of the heat transfer pipes is mitigated, and heat transfer performance, earth quake resistance and maintenancability are improved. (I.N.)
Low-temperature Condensation of Carbon
Krasnokutski, S. A.; Goulart, M.; Gordon, E. B.; Ritsch, A.; Jäger, C.; Rastogi, M.; Salvenmoser, W.; Henning, Th.; Scheier, P.
2017-10-01
Two different types of experiments were performed. In the first experiment, we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium, while in the second experiment, we studied the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high temperatures, supposedly higher than 1000°C, during condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperature condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers. Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via the addition of carbon atoms to H2 and CO molecules ({{C}}+{{{H}}}2\\to {HCH},{HCH}+{CO}\\to {{OCCH}}2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.
Motion of vortices in inhomogeneous Bose-Einstein condensates
Groszek, Andrew J.; Paganin, David M.; Helmerson, Kristian; Simula, Tapio P.
2018-02-01
We derive a general and exact equation of motion for a quantized vortex in an inhomogeneous two-dimensional Bose-Einstein condensate. This equation expresses the velocity of a vortex as a sum of local ambient density and phase gradients in the vicinity of the vortex. We perform Gross-Pitaevskii simulations of single-vortex dynamics in both harmonic and hard-walled disk-shaped traps, and find excellent agreement in both cases with our analytical prediction. The simulations reveal that, in a harmonic trap, the main contribution to the vortex velocity is an induced ambient phase gradient, a finding that contradicts the commonly quoted result that the local density gradient is the only relevant effect in this scenario. We use our analytical vortex velocity formula to derive a point-vortex model that accounts for both density and phase contributions to the vortex velocity, suitable for use in inhomogeneous condensates. Although good agreement is obtained between Gross-Pitaevskii and point-vortex simulations for specific few-vortex configurations, the effects of nonuniform condensate density are in general highly nontrivial, and are thus difficult to efficiently and accurately model using a simplified point-vortex description.
Development and Evaluation of a Sandia Cooler-based Refrigerator Condenser
Energy Technology Data Exchange (ETDEWEB)
Johnson, Terry A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kariya, Harumichi Arthur [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Leick, Michael T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zimmerman, Mark D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Li, Manjie [Univ. of Maryland, College Park, MD (United States); Du, Yilin [Univ. of Maryland, College Park, MD (United States); Lee, Hoseong [Univ. of Maryland, College Park, MD (United States); Hwang, Yunho [Univ. of Maryland, College Park, MD (United States); Radermacher, Reinhard [Univ. of Maryland, College Park, MD (United States)
2015-07-01
This report describes the first design of a refrigerator condenser using the Sandia Cooler, i.e. air - bearing supported rotating heat - sink impeller. The project included ba seline performance testing of a residential refrigerator, analysis and design development of a Sandia Cooler condenser assembly including a spiral channel baseplate, and performance measurement and validation of this condenser system as incorporated into the residential refrigerator. Comparable performance was achieved in a 60% smaller volume package. The improved modeling parameters can now be used to guide more optimized designs and more accurately predict performance.
Galimberti, Daria Ruth; Milani, Alberto; Gaigeot, Marie-Pierre; Radice, Stefano; Tonelli, Claudio; Picozzi, Rosaldo; Castiglioni, Chiara
2017-08-01
First-principles molecular dynamics (FPMD) simulations in the framework of Density Functional Theory (DFT) are carried out for the prediction of the infrared spectrum of the fluorinated molecule ClCF2CF(CF3)OCF2CH3 in liquid and gas phase. This molecule is characterized by a flexible structure, allowing the co-existence of several stable conformers, that differ by values of the torsional angles. FPMD computed spectra are compared to the experimental ones, and to Boltzmann weighted IR spectra based on gas phase calculations.
Vapor condensation onto a non-volatile liquid drop
Energy Technology Data Exchange (ETDEWEB)
Inci, Levent; Bowles, Richard K., E-mail: richard.bowles@usask.ca [Department of Chemistry, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5C9 (Canada)
2013-12-07
Molecular dynamics simulations of miscible and partially miscible binary Lennard–Jones mixtures are used to study the dynamics and thermodynamics of vapor condensation onto a non-volatile liquid drop in the canonical ensemble. When the system volume is large, the driving force for condensation is low and only a submonolayer of the solvent is adsorbed onto the liquid drop. A small degree of mixing of the solvent phase into the core of the particles occurs for the miscible system. At smaller volumes, complete film formation is observed and the dynamics of film growth are dominated by cluster-cluster coalescence. Mixing into the core of the droplet is also observed for partially miscible systems below an onset volume suggesting the presence of a solubility transition. We also develop a non-volatile liquid drop model, based on the capillarity approximations, that exhibits a solubility transition between small and large drops for partially miscible mixtures and has a hysteresis loop similar to the one observed in the deliquescence of small soluble salt particles. The properties of the model are compared to our simulation results and the model is used to study the formulation of classical nucleation theory for systems with low free energy barriers.
Active condensation of water by plants
Directory of Open Access Journals (Sweden)
Prokhorov Alexey Anatolievich
2013-10-01
Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.
Quark virtuality and QCD vacuum condensates
International Nuclear Information System (INIS)
Zhou Lijuan; Ma Weixing
2004-01-01
Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions