Bose-Einstein condensation and chiral phase transition in linear sigma model

International Nuclear Information System (INIS)

Shu Song; Li Jiarong

2005-01-01

With the linear sigma model, we have studied Bose-Einstein condensation and the chiral phase transition in the chiral limit for an interacting pion system. A μ-T phase diagram including these two phenomena is presented. It is found that the phase plane has been divided into three areas: the Bose-Einstein condensation area, the chiral symmetry broken phase area and the chiral symmetry restored phase area. Bose-Einstein condensation can occur either from the chiral symmetry broken phase or from the restored phase. We show that the onset of the chiral phase transition is restricted in the area where there is no Bose-Einstein condensation

String-net condensation: A physical mechanism for topological phases

International Nuclear Information System (INIS)

Levin, Michael A.; Wen Xiaogang

2005-01-01

We show that quantum systems of extended objects naturally give rise to a large class of exotic phases--namely topological phases. These phases occur when extended objects, called ''string-nets,'' become highly fluctuating and condense. We construct a large class of exactly soluble 2D spin Hamiltonians whose ground states are string-net condensed. Each ground state corresponds to a different parity invariant topological phase. The models reveal the mathematical framework underlying topological phases: tensor category theory. One of the Hamiltonians--a spin-1/2 system on the honeycomb lattice--is a simple theoretical realization of a universal fault tolerant quantum computer. The higher dimensional case also yields an interesting result: we find that 3D string-net condensation naturally gives rise to both emergent gauge bosons and emergent fermions. Thus, string-net condensation provides a mechanism for unifying gauge bosons and fermions in 3 and higher dimensions

A Local Condensation Analysis Representing Two-phase Annular Flow in Condenser/radiator Capillary Tubes

Science.gov (United States)

Karimi, Amir

1991-01-01

NASA's effort for the thermal environmental control of the Space Station Freedom is directed towards the design, analysis, and development of an Active Thermal Control System (ATCS). A two phase, flow through condenser/radiator concept was baselined, as a part of the ATCS, for the radiation of space station thermal load into space. The proposed condenser rejects heat through direct condensation of ATCS working fluid (ammonia) in the small diameter radiator tubes. Analysis of the condensation process and design of condenser tubes are based on the available two phase flow models for the prediction of flow regimes, heat transfer, and pressure drops. The prediction formulas use the existing empirical relationships of friction factor at gas-liquid interface. An attempt is made to study the stability of interfacial waves in two phase annular flow. The formulation is presented of a stability problem in cylindrical coordinates. The contribution of fluid viscosity, surface tension, and transverse radius of curvature to the interfacial surface is included. A solution is obtained for Kelvin-Helmholtz instability problem which can be used to determine the critical and most dangerous wavelengths for interfacial waves.

Condensation shocks in high momentum two-phase flows in condensing injectors

International Nuclear Information System (INIS)

Anand, G.; Christensen, R.N.

1993-01-01

This study presents a phenomenological and mathematical model of condensation shocks in high momentum two-phase flows in condensing injectors. The characteristics of the shock were related to the mode of vapor bubble collapse. Using cavitation terminology, the bubble collapse can be classified as inertially controlled or thermally controlled. Inertial bubble collapse occurs rapidly whereas, a thermally controlled collapse results in a significantly longer collapse time. The interdependence between the bubble collapse mode and the momentum and pressure of the flow, was analyzed in this study. For low-temperature-high-velocity flows a steep pressure rise with complete condensation was obtained. For a high-temperature-low velocity flow with noncondensables, low pressure recovery with incomplete condensation was observed. These trends are in agreement with previous experimental observations

Cold storage condensation heat recovery system with a novel composite phase change material

International Nuclear Information System (INIS)

Xia, Mingzhu; Yuan, Yanping; Zhao, Xudong; Cao, Xiaoling; Tang, Zhonghua

2016-01-01

Highlights: • Cold storage condensation heat recovery system using PCM was proposed. • CW with a phase change temperature of nearly 80 °C was selected as the potential PCM. • The optimal mass ratio between the CW and EG was 10:1. • The thermal and physical performances of the CW/EG were investigated. • The thermal reliability was demonstrated by 1000 cycles. - Abstract: Using condensation heat from cold storage refrigeration systems to provide heat for domestic hot water preparation and industrial hot water supply promotes energy conservation. However, few studies have investigated cold storage condensation heat recovery using phase change materials (PCMs). In this study, a cold storage condensation heat recovery system that uses PCMs has been designed and analysed. According to the principle of energy cascade recycling, different operation modes could be effectively switched to recycle condensation heat. Furthermore, a novel and suitable phase change composite material is developed for cold storage condensation heat recovery, which has a relatively large latent heat, high thermal conductivity, and an appropriate phase change temperature (i.e. 80 °C). With carnauba wax (CW) as the PCM and expanded graphite (EG) as the additive, a composite was developed with an optimal mass ratio of CW:EG = 10:1. The thermal and physical properties and the interior structure of the composite were then investigated using a scanning electron microscope (SEM), thermal constants analyser (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting and solidification processes and accelerated thermal cycling were also conducted. It was found that at the optimal mass ratio of 10:1, the temperatures of the CW/EG composite in the melting and solidification processes were 81.98 °C and 80.43 °C, respectively, while the corresponding latent heats were 150.9 J/g and 142.6 J/g, respectively

The phase transition to an inhomogeneous condensate state

International Nuclear Information System (INIS)

Voskresensky, D.N.

1984-01-01

The Lagrangian (free energy) of the model with a complex scalar order parameter in which the phase transition to an inhomogeneous condensate state exists is constructed in the coordinate representation. In the case of condensation of charged particles (for example paired electrons) interaction with the electromagnetic field is included. The excitation spectrum in the presence of the condensate is found. The oscillations are strongly anisotropic. It is shown that superfluidity is absent for an uncharged system but that the charged one has the property of superconductivity. The important role of thermal fluctuations is demonstrated. They drastically change the behaviour of the condensate system. The condensation in a finite system is considered. A study is carried out for the behaviour of an inhomogeneous condensate in magnetic field. It is shown that the inhomogeneous condensate is a type II superconductor with Ginzburg-Landau parameter kappa >> 1, but that the structure of the mixed state of the system is unusual - consisting of plane layers of the normal phase, when Hsub(c1)< H< H'sub(c2). The distribution of condensate in the strong magnetic field H'sub(c2)< H< Hsub(c2) is also studied. (Auth.)

Oscillatory solitons and time-resolved phase locking of two polariton condensates

International Nuclear Information System (INIS)

Christmann, Gabriel; Tosi, Guilherme; Baumberg, Jeremy J; Berloff, Natalia G; Tsotsis, Panagiotis; Eldridge, Peter S; Hatzopoulos, Zacharias; Savvidis, Pavlos G

2014-01-01

When pumped nonresonantly, semiconductor microcavity polaritons form Bose–Einstein condensates that can be manipulated optically. Using tightly-focused excitation spots, radially expanding condensates can be formed in close proximity. Using high time resolution streak camera measurements we study the time dependent properties of these macroscopic coherent states. By coupling this method with interferometry we observe directly the phase locking of two independent condensates in time, showing the effect of polariton–polariton interactions. We also directly observe fast spontaneous soliton-like oscillations of the polariton cloud trapped between the pump spots, which can be either dark or bright solitons. This transition from dark to bright is a consequence of the change of sign of the nonlinearity which we propose is due to the shape of the polariton dispersion leading to either positive or negative polariton effective mass. (paper)

Hot atom chemistry of monovalent atoms in organic condensed phases

International Nuclear Information System (INIS)

Stoecklin, G.

1975-01-01

The advantages and disadvantages of hot atom studies in condensed organic phases are considered, and recent advances in condensed phase organic hot atom chemistry of recoil tritium and halogen atoms are discussed. Details are presented of the present status and understanding of liquid phase hot atom chemistry and also that of organic solids. The consequences of the Auger effect in condensed organic systems are also considered. (author)

Heat and mass transfer with condensation in capillary porous bodies.

Science.gov (United States)

Larbi, Salah

2014-01-01

The purpose of this present work is related to wetting process analysis caused by condensation phenomena in capillary porous material by using a numerical simulation. Special emphasis is given to the study of the mechanism involved and the evaluation of classical theoretical models used as a predictive tool. A further discussion will be given for the distribution of the liquid phase for both its pendular and its funicular state and its consequence on diffusion coefficients of the mathematical model used. Beyond the complexity of the interaction effects between vaporisation-condensation processes on the gas-liquid interfaces, the comparison between experimental and numerical simulations permits to identify the specific contribution and the relative part of mass and energy transport parameters. This analysis allows us to understand the contribution of each part of the mathematical model used and to simplify the study.

Heat and Mass Transfer with Condensation in Capillary Porous Bodies

Directory of Open Access Journals (Sweden)

Salah Larbi

2014-01-01

Full Text Available The purpose of this present work is related to wetting process analysis caused by condensation phenomena in capillary porous material by using a numerical simulation. Special emphasis is given to the study of the mechanism involved and the evaluation of classical theoretical models used as a predictive tool. A further discussion will be given for the distribution of the liquid phase for both its pendular and its funicular state and its consequence on diffusion coefficients of the mathematical model used. Beyond the complexity of the interaction effects between vaporisation-condensation processes on the gas-liquid interfaces, the comparison between experimental and numerical simulations permits to identify the specific contribution and the relative part of mass and energy transport parameters. This analysis allows us to understand the contribution of each part of the mathematical model used and to simplify the study.

Operando Spectroscopy of the Gas-Phase Aldol Condensation of Propanal over Solid Base Catalysts

NARCIS (Netherlands)

Hernández-giménez, Ana M.; Ruiz-martínez, Javier; Puértolas, Begoña; Pérez-ramírez, Javier; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

2017-01-01

The gas-phase aldol condensation of propanal, taken as model for the aldehyde components in bio-oils, has been studied with a combined operando set-up allowing to perform FT-IR & UV–Vis diffuse reflectance spectroscopy (DRS) with on-line mass spectrometry (MS). The selected solid base catalysts, a

Mass-spectral investigations of vaporization process of the condensed zinc phosphates

International Nuclear Information System (INIS)

Lopatin, S.L; Sinyayev, V.A.; Shugurov, S.M.

2005-01-01

There are the data of high temperature mass-spectrum experiment concerning of thermal decomposition of zinc cyclotriphosphate and zinc diphosphate presented in the given article. It is shown the both salts dissociate into phosphorus oxides, oxygen, and atomic zinc. Correlation between partial pressure of vapor components and composition of condensed phase are described. Effects of temperature and duration of the vaporization process on vapor composition are presented as well. Standard enthalpy of ZnPO 3 molecule decomposition into atoms is calculated. [author

Numerical Method based on SIMPLE Algorithm for a Two-Phase Flow with Non-condensable Gas

International Nuclear Information System (INIS)

Kim, Jong Tae

2009-08-01

In this study, a numerical method based on SIMPLE algorithm for a two-phase flow with non-condensable gas has been developed in order to simulate thermal hydraulics in a containment of a nuclear power plant. As governing equations, it adopts a two-fluid three-field model for the two-phase flows. The three fields include gas, drops, and continuous liquid. The gas field can contains vapor and non-condensable gases such as air and hydrogen. In order to resolve mixing phenomena of gas species, gas transport equations for each species base on the gas mass fractions are solved with gas phase governing equations such as mass, momentum and energy equations. Methods to evaluate the properties of the gas species were implemented in the code. They are constant or polynomial function based a user input and a property library from Chemkin and JANAF table for gas specific heat. Properties for the gas mixture which are dependent on mole fractions of the gas species were evaluated by a mix rule

Chiral condensate from the twisted mass Dirac operator spectrum

International Nuclear Information System (INIS)

Cichy, Krzysztof; Jansen, Karl; Cyprus Univ., Nicosia

2013-03-01

We present the results of our computation of the chiral condensate with N f =2 and N 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 f =2 and N f =2+1+1 dynamical flavours.

Condensed phase preparation of 2,3-pentanedione

Science.gov (United States)

Miller, D.J.; Perry, S.M.; Fanson, P.T.; Jackson, J.E.

1998-11-03

A condensed phase process for the preparation of purified 2,3-pentanedione from lactic acid and an alkali metal lactate is described. The process uses elevated temperatures between about 200 to 360 C for heating a reaction mixture of lactic acid and an alkali metal lactate to produce the 2,3-pentanedione in a reaction vessel. The 2,3-pentanedione produced is vaporized from the reaction vessel and condensed with water. 5 figs.

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.

Investigations of effect of phase change mass transfer rate on cavitation process with homogeneous relaxation model

Energy Technology Data Exchange (ETDEWEB)

He, Zhixia; Zhang, Liang; Saha, Kaushik; Som, Sibendu; Duan, Lian; Wang, Qian

2017-12-01

The super high fuel injection pressure and micro size of nozzle orifice has been an important development trend for the fuel injection system. Accordingly, cavitation transient process, fuel compressibility, amount of noncondensable gas in the fuel and cavitation erosion have attracted more attention. Based on the fact of cavitation in itself is a kind of thermodynamic phase change process, this paper takes the perspective of the cavitation phase change mass transfer process to analyze above mentioned phenomenon. The two-phase cavitating turbulent flow simulations with VOF approach coupled with HRM cavitation model and U-RANS of standard k-ε turbulence model were performed for investigations of cavitation phase change mass transfer process. It is concluded the mass transfer time scale coefficient in the Homogenous Relaxation Model (HRM) representing mass transfer rate should tend to be as small as possible in a condition that ensured the solver stable. At very fast mass transfer rate, the phase change occurs at very thin interface between liquid and vapor phase and condensation occurs more focused and then will contribute predictably to a more serious cavitation erosion. Both the initial non-condensable gas in fuel and the fuel compressibility can accelerate the cavitation mass transfer process.

Vortices in a rotating dark matter condensate

International Nuclear Information System (INIS)

Yu, Rotha P; Morgan, Michael J

2002-01-01

We examine vortices in a self-gravitating dark matter Bose-Einstein condensate (BEC), consisting of ultra-low mass scalar bosons that arise during a late-time cosmological phase transition. Rotation of the dark matter BEC imprints a background phase gradient on the condensate, which establishes a harmonic trap potential for vortices. A numerical simulation of vortex dynamics shows that the vortex number density, n v ∝ r -1 , resulting in a flat velocity profile for the dark matter condensate. (letter to the editor)

INTENSIFICATION OF HEAT- AND MASS TRANSFER IN EVAPORATION - CONDENSATION DEVICES

Directory of Open Access Journals (Sweden)

A. G. Kulakov

2005-01-01

Full Text Available Results of investigation of capillary structure properties used in evaporation – condensation devices are presented.Constructive solutions for intensification of heat transfer in evaporation and condensation heat exchangers are offered. The obtained heat transfer experimental data at film-type vapor conden-sation are generalized in criterion form.Description of general rule of heat and mass transfer processes in miniature heat pipes with three various capillary structures at wide range of operating parameters is given in the paper.

Molecular simulation of steady-state evaporation and condensation in the presence of a non-condensable gas

Science.gov (United States)

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.

Condensation During Nuclear Reactor Loca

International Nuclear Information System (INIS)

Rihan, Y.; Teamah, M.; Sorour, M.; Soliman, S.

2008-01-01

Two-phase channel flow with condensation is a common phenomenon occurs in a number of nuclear reactor accident scenarios. It also plays an important role during the operation of the safety coolant injection systems in advanced nuclear reactors. Semiempirical correlations and simple models based on the analogy between heat and mass transfer processes have been previously applied. Rigorous models, compatible with the state-of-the-art numerical algorithms used in thermal-hydraulic computer codes, are scare, and are of great interest. The objective of this research is to develop a method for modeling condensation, with noncondensable gases, compatible with the state-of-the-art numerical methods for the solution of multi-phase field equations. A methodology for modeling condensation, based on the stagnant film theory, and compatible with the reviewed numerical algorithms, is developed. The model treats the coupling between the heat and mass transfer processes, and allows for an implicit treatment of the mass and momentum exchange terms as the gas-liquid interphase, without iterations. The developed model was used in the application of loss of coolant in pressurized water reactor accidents

Disorder Induced Dynamic Equilibrium Localization and Random Phase Steps of Bose—Einstein Condensates

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)

Characterization of condensed phase nitric acid particles formed in the gas phase

Institute of Scientific and Technical Information of China (English)

Long Jia; Yongfu Xu

2011-01-01

The formation of nitric acid hydrates has been observed in a chamber during the dark reaction of NO2 with O3 in the presence of air.The size of condensed phase nitric acid was measured to be 40-100 nm and 20-65 nm at relative humidity (RH) ≤ 5％ and RH = 67％ under our experimental conditions, respectively.The nitric acid particles were collected on the glass fiber membrane and their chemical compositions were analyzed by infrared spectrum.The main components of nitric acid hydrates in particles are HNO3·3H2O and NO3-·xH2O (x≥ 4) at low RH, whereas at high RH HNO3·H2O, HNO3·2H2O, HNO3·3H2O and NO3-·xH2O (x≥ 4) all exist in the condensed phase.At high RH HNO3·xH2O (x ≤ 3) collected on the glass fiber membrane is greatly increased, while NO3-·xH2O (x ≥4) decreased, compared with low RH.To the best of our knowledge, this is the first time to report that condensed phase nitric acid can be generated in the gas phase at room temperature.

Evaporation and Condensation Flows of a Vapor-Gas Mixture from or onto the Condensed Phase with an Internal Structure

National Research Council Canada - National Science Library

Onishi, Yoshimoto; Yamada, Ken

2005-01-01

Transient motions of a vapor-gas mixture due to the evaporation and condensation processes from or onto the plane condensed phase, with a temperature field as its internal structure, have been studied...

Constructing a unique two-phase compressibility factor model for lean gas condensates

Energy Technology Data Exchange (ETDEWEB)

Moayyedi, Mahmood; Gharesheikhlou, Aliashghar [Research Institute of Petroleum Industry (RIPI), Tehran (Iran, Islamic Republic of); Azamifard, Arash; Mosaferi, Emadoddin [Amirkabir University of Technology (AUT), Tehran (Iran, Islamic Republic of)

2015-02-15

Generating a reliable experimental model for two-phase compressibility factor in lean gas condensate reservoirs has always been demanding, but it was neglected due to lack of required experimental data. This study presents the main results of constructing the first two-phase compressibility factor model that is completely valid for Iranian lean gas condensate reservoirs. Based on a wide range of experimental data bank for Iranian lean gas condensate reservoirs, a unique two-phase compressibility factor model was generated using design of experiments (DOE) method and neural network technique (ANN). Using DOE, a swift cubic response surface model was generated for two-phase compressibility factor as a function of some selected fluid parameters for lean gas condensate fluids. The proposed DOE and ANN models were finally validated using four new independent data series. The results showed that there is a good agreement between experimental data and the proposed models. In the end, a detailed comparison was made between the results of proposed models.

Constructing a unique two-phase compressibility factor model for lean gas condensates

International Nuclear Information System (INIS)

Moayyedi, Mahmood; Gharesheikhlou, Aliashghar; Azamifard, Arash; Mosaferi, Emadoddin

2015-01-01

Generating a reliable experimental model for two-phase compressibility factor in lean gas condensate reservoirs has always been demanding, but it was neglected due to lack of required experimental data. This study presents the main results of constructing the first two-phase compressibility factor model that is completely valid for Iranian lean gas condensate reservoirs. Based on a wide range of experimental data bank for Iranian lean gas condensate reservoirs, a unique two-phase compressibility factor model was generated using design of experiments (DOE) method and neural network technique (ANN). Using DOE, a swift cubic response surface model was generated for two-phase compressibility factor as a function of some selected fluid parameters for lean gas condensate fluids. The proposed DOE and ANN models were finally validated using four new independent data series. The results showed that there is a good agreement between experimental data and the proposed models. In the end, a detailed comparison was made between the results of proposed models

Effective-mass analysis of Bose-Einstein condensates in optical lattices: Stabilization and levitation

International Nuclear Information System (INIS)

Pu, H.; Zhang, W.; Meystre, P.; Baksmaty, L.O.; Bigelow, N.P.

2003-01-01

We investigate the time evolution of a Bose-Einstein condensate in a periodic optical potential. Using an effective mass formalism, we study the equation of motion for the envelope function modulating the Bloch states of the lattice potential. In particular, we show how the negative effective-mass affects the dynamics of the condensate

Opportunities for sub-laser-cycle spectroscopy in condensed phase

International Nuclear Information System (INIS)

Ivanov, Misha; Smirnova, Olga

2013-01-01

Highlights: ► We discuss how sub-cycle attosecond spectroscopy can be extended from gas to condensed phase. ► We show that attosecond streaking measurements can be applied to bound electrons. ► We discuss time-resolving the formation of band structure in laser fields. - Abstract: To a large extent, progress of attosecond spectroscopy in the gas phase has been driven by designing approaches where time-resolution is not limited by the pulse duration. Instead, the time resolution comes from exploiting the sensitivity of electronic response to the oscillations of the electric field in the laser pulse and attosecond control over these oscillations. This paper discusses perspectives and opportunities for transporting the ideas of sub-cycle spectroscopy from gas to condensed phase

Condensed matter physics

CERN Document Server

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.

Analytical methodologies for broad metabolite coverage of exhaled breath condensate.

Science.gov (United States)

Aksenov, Alexander A; Zamuruyev, Konstantin O; Pasamontes, Alberto; Brown, Joshua F; Schivo, Michael; Foutouhi, Soraya; Weimer, Bart C; Kenyon, Nicholas J; Davis, Cristina E

2017-09-01

Breath analysis has been gaining popularity as a non-invasive technique that is amenable to a broad range of medical uses. One of the persistent problems hampering the wide application of the breath analysis method is measurement variability of metabolite abundances stemming from differences in both sampling and analysis methodologies used in various studies. Mass spectrometry has been a method of choice for comprehensive metabolomic analysis. For the first time in the present study, we juxtapose the most commonly employed mass spectrometry-based analysis methodologies and directly compare the resultant coverages of detected compounds in exhaled breath condensate in order to guide methodology choices for exhaled breath condensate analysis studies. Four methods were explored to broaden the range of measured compounds across both the volatile and non-volatile domain. Liquid phase sampling with polyacrylate Solid-Phase MicroExtraction fiber, liquid phase extraction with a polydimethylsiloxane patch, and headspace sampling using Carboxen/Polydimethylsiloxane Solid-Phase MicroExtraction (SPME) followed by gas chromatography mass spectrometry were tested for the analysis of volatile fraction. Hydrophilic interaction liquid chromatography and reversed-phase chromatography high performance liquid chromatography mass spectrometry were used for analysis of non-volatile fraction. We found that liquid phase breath condensate extraction was notably superior compared to headspace extraction and differences in employed sorbents manifested altered metabolite coverages. The most pronounced effect was substantially enhanced metabolite capture for larger, higher-boiling compounds using polyacrylate SPME liquid phase sampling. The analysis of the non-volatile fraction of breath condensate by hydrophilic and reverse phase high performance liquid chromatography mass spectrometry indicated orthogonal metabolite coverage by these chromatography modes. We found that the metabolite coverage

Three-dimensional two-phase mass transport model for direct methanol fuel cells

International Nuclear Information System (INIS)

Yang, W.W.; Zhao, T.S.; Xu, C.

2007-01-01

A three-dimensional (3D) steady-state model for liquid feed direct methanol fuel cells (DMFC) is presented in this paper. This 3D mass transport model is formed by integrating five sub-models, including a modified drift-flux model for the anode flow field, a two-phase mass transport model for the porous anode, a single-phase model for the polymer electrolyte membrane, a two-phase mass transport model for the porous cathode, and a homogeneous mist-flow model for the cathode flow field. The two-phase mass transport models take account the effect of non-equilibrium evaporation/ condensation at the gas-liquid interface. A 3D computer code is then developed based on the integrated model. After being validated against the experimental data reported in the literature, the code was used to investigate numerically transport behaviors at the DMFC anode and their effects on cell performance

Anomalous interfacial tension temperature dependence of condensed phase drops in magnetic fluids

Science.gov (United States)

Ivanov, Aleksey S.

2018-05-01

Interfacial tension temperature dependence σ(T) of the condensed phase (drop-like aggregates) in magnetic fluids undergoing field induced phase transition of the "gas-liquid" type was studied experimentally. Numerical analysis of the experimental data has revealed the anomalous (if compared to ordinary one-component fluids) behavior of the σ(T) function for all tested magnetic colloid samples: the condensed phase drops at high T ≈ 75 C exhibit higher σ(T) than the drops condensed at low T ≈ 20 C. The σ(T) behavior is explained by the polydispersity of magnetic colloids: at high T, only the largest colloidal particles are able to take part in the field induced condensation; thus, the increase of T causes the growth of the average particle diameters inside the drop-like aggregates, what in its turn results in the growth of σ(T). The result is confirmed by qualitative theoretical estimations and qualitative experimental observation of the condensed phase "evaporation" process after the applied magnetic field is removed: the drops that are formed due to capillary instability of the drop-like aggregates retract by one order of magnitude faster at high T, and the evaporation of the drops slows down at high T.

Fermion condensation quantum phase transition versus conventional quantum phase transitions

International Nuclear Information System (INIS)

Shaginyan, V.R.; Han, J.G.; Lee, J.

2004-01-01

The main features of fermion condensation quantum phase transition (FCQPT), which are distinctive in several aspects from that of conventional quantum phase transition (CQPT), are considered. We show that in contrast to CQPT, whose physics in quantum critical region is dominated by thermal and quantum fluctuations and characterized by the absence of quasiparticles, the physics of a Fermi system near FCQPT or undergone FCQPT is controlled by the system of quasiparticles resembling the Landau quasiparticles. Contrary to the Landau quasiparticles, the effective mass of these quasiparticles strongly depends on the temperature, magnetic fields, density, etc. This system of quasiparticles having general properties determines the universal behavior of the Fermi system in question. As a result, the universal behavior persists up to relatively high temperatures comparatively to the case when such a behavior is determined by CQPT. We analyze striking recent measurements of specific heat, charge and heat transport used to study the nature of magnetic field-induced QCP in heavy-fermion metal CeCoIn 5 and show that the observed facts are in good agreement with our scenario based on FCQPT and certainly seem to rule out the critical fluctuations related with CQPT. Our general consideration suggests that FCQPT and the emergence of novel quasiparticles near and behind FCQPT and resembling the Landau quasiparticles are distinctive features intrinsic to strongly correlated substances

Quark masses from quark-gluon condensates in a modified perturbative QCD

CERN Document Server

Cabo-Montes de Oca, Alejandro

2003-01-01

In this note, it is argued that the mass matrix for the six quarks can be generated in first approximation by introducing fermion condensates on the same lines as was done before for gluons, within the modified perturbative expansion for QCD proposed in former works. Thus, the results point in the direction of the conjectured link of the approximate `Democratic' symmetry of the quark mass matrix and `gap' effects similar to the ones occuring in superconductivity. The condensates are introduced here non-dynamically and therefore the question of the possibility for their spontaneous generation remains open. However, possible ways out of the predicted lack of the `Democratic' symmetry of the condensates resulting from the spontaneous breaking of the flavour symmetry are suggested. They come from an analysis based on the Cornwall--Jackiw--Tomboulis (CJT) effective potential for composite operators

Experimental Investigation of Flow Condensation in Microgravity

Science.gov (United States)

Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.;

Phase-driven collapse of the Cooper condensate in a nanosized superconductor

Science.gov (United States)

Ronzani, Alberto; D'Ambrosio, Sophie; Virtanen, Pauli; Giazotto, Francesco; Altimiras, Carles

2017-12-01

Superconductivity can be understood in terms of a phase transition from an uncorrelated electron gas to a condensate of Cooper pairs in which the relative phases of the constituent electrons are coherent over macroscopic length scales. The degree of correlation is quantified by a complex-valued order parameter, whose amplitude is proportional to the strength of the pairing potential in the condensate. Supercurrent-carrying states are associated with nonzero values of the spatial gradient of the phase. The pairing potential and several physical observables of the Cooper condensate can be manipulated by means of temperature, current bias, dishomogeneities in the chemical composition, or application of a magnetic field. Here we show evidence of complete suppression of the energy gap in the local density of quasiparticle states (DOS) of a superconducting nanowire upon establishing a phase difference equal to π over a length scale comparable to the superconducting coherence length. These observations are consistent with a complete collapse of the pairing potential in the center of the wire, in accordance with theoretical modeling based on the quasiclassical theory of superconductivity in diffusive systems. Our spectroscopic data, fully exploring the phase-biased states of the condensate, highlight the profound effect that extreme phase gradients exert on the amplitude of the pairing potential. Moreover, the sharp magnetic response (up to 27 mV/Φ0) observed near the onset of the superconducting gap collapse regime is exploited to realize magnetic flux detectors with noise-equivalent resolution as low as 260 n Φ0/√{Hz} .

Quantum mechanical force fields for condensed phase molecular simulations

Science.gov (United States)

Giese, Timothy J.; York, Darrin M.

2017-09-01

Molecular simulations are powerful tools for providing atomic-level details into complex chemical and physical processes that occur in the condensed phase. For strongly interacting systems where quantum many-body effects are known to play an important role, density-functional methods are often used to provide the model with the potential energy used to drive dynamics. These methods, however, suffer from two major drawbacks. First, they are often too computationally intensive to practically apply to large systems over long time scales, limiting their scope of application. Second, there remain challenges for these models to obtain the necessary level of accuracy for weak non-bonded interactions to obtain quantitative accuracy for a wide range of condensed phase properties. Quantum mechanical force fields (QMFFs) provide a potential solution to both of these limitations. In this review, we address recent advances in the development of QMFFs for condensed phase simulations. In particular, we examine the development of QMFF models using both approximate and ab initio density-functional models, the treatment of short-ranged non-bonded and long-ranged electrostatic interactions, and stability issues in molecular dynamics calculations. Example calculations are provided for crystalline systems, liquid water, and ionic liquids. We conclude with a perspective for emerging challenges and future research directions.

Maintenance of order in a moving strong condensate

International Nuclear Information System (INIS)

Whitehouse, Justin; Costa, André; Blythe, Richard A; Evans, Martin R

2014-01-01

We investigate the conditions under which a moving condensate may exist in a driven mass transport system. Our paradigm is a minimal mass transport model in which n − 1 particles move simultaneously from a site containing n > 1 particles to the neighbouring site in a preferred direction. In the spirit of a zero-range process the rate u(n) of this move depends only on the occupation of the departure site. We study a hopping rate u(n) = 1 + b/n α numerically and find a moving strong condensate phase for b > b c (α) for all α > 0. This phase is characterised by a condensate that moves through the system and comprises a fraction of the system's mass that tends to unity. The mass lost by the condensate as it moves is constantly replenished from the trailing tail of low occupancy sites that collectively comprise a vanishing fraction of the mass. We formulate an approximate analytical treatment of the model that allows a reasonable estimate of b c (α) to be obtained. We show numerically (for α = 1) that the transition is of mixed order, exhibiting a discontinuity in the order parameter as well as a diverging length scale as b↘b c . (paper)

Implementation and validation of a condensation model in ANSYS

International Nuclear Information System (INIS)

Lehmkuhl, J.; Kelm, S.; Allelein, H.J.; Forschungszentrum Juelich

2012-01-01

During design-based beyond-design accidents large amounts of steam and hydrogen are released onto the containment. The knowledge on the local distribution of gases and atmospheric conditions is therefore necessary for the design of safety systems or emergency measures. Condensation processes have a significant influence on the thermal hydraulics, the hydrogen combustion and the aerosol behavior in the containment. The presented one-phase condensation model was developed for an effective CFD modeling of condensation processes in ANSYS CFX for accident analyses. Based on the assumption that wall condensation is mainly determined by the mass transport the assumption of thermal equilibrium can be used for one-phase calculations. The modeling concept is applicable for wall and volume condensation and has been implemented.

To the generalization of experimental data on heat and mass transfer in evaporation and condensation

International Nuclear Information System (INIS)

Berman, L.D.

1980-01-01

Similarity equations for heat-and-mass transfer in binary gas or steam-gas layers in the processes of liquid evaporation, condensation and desublimation of vapours, desorption and absorption and porous body cooling are considered. It is accepted that steam-gas components obey to the equation of ideal gas state and that evaporation and condensation condititons permit to neglect the influence of compressability of gas (steam-gas) mixture, non-isothermality of boundary layer and interphase kinetic resistance to mass transfer onto the interfaces. It is concluded that the results of considered experimental and theoretical investigations of the above processes are in a satisfactory agreement and show insignificance of the effect of hydrodynamic conditions determining the regime of main steam-gas mixture flow on relative heat-and-mass transfer coefficients. According to the theoretical calculation results with increase of the factor of M steam-gas mixture non-uniformity mass transfer intensity in evaporation decreases, while in condensation it grows, but M effect on the mass transfer coefficient is rather small and sowhat increases in the case of a turbulent boundary layer evaporation. In condensation it is less than in evaporation

Phase Transitions of the Polariton Condensate in 2D Dirac Materials.

Science.gov (United States)

Lee, Ki Hoon; Lee, Changhee; Min, Hongki; Chung, Suk Bum

2018-04-13

For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon (e-ph) coupling can lead to the hybridizations of the exciton and the cavity photon known as polaritons, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped two-dimensional Dirac material such as the transition metal dichalcogenide MoS_{2} or WSe_{2}. Specifically, in forming the polariton, the e-ph coupling from the optical selection rule due to the Berry phase can compete against the Coulomb electron-electron (e-e) interaction. We find that this competition gives rise to a rich phase diagram for the polariton condensate involving both topological and symmetry breaking phase transitions, with the former giving rise to the quantum anomalous Hall and the quantum spin Hall phases.

Phase Transitions of the Polariton Condensate in 2D Dirac Materials

Science.gov (United States)

Lee, Ki Hoon; Lee, Changhee; Min, Hongki; Chung, Suk Bum

2018-04-01

For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon (e -ph) coupling can lead to the hybridizations of the exciton and the cavity photon known as polaritons, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped two-dimensional Dirac material such as the transition metal dichalcogenide MoS2 or WSe2 . Specifically, in forming the polariton, the e -ph coupling from the optical selection rule due to the Berry phase can compete against the Coulomb electron-electron (e -e ) interaction. We find that this competition gives rise to a rich phase diagram for the polariton condensate involving both topological and symmetry breaking phase transitions, with the former giving rise to the quantum anomalous Hall and the quantum spin Hall phases.

Investigation into the determination of trimethylarsine in natural gas and its partitioning into gas and condensate phases using (cryotrapping)/gas chromatography coupled to inductively coupled plasma mass spectrometry and liquid/solid sorption techniques

International Nuclear Information System (INIS)

Krupp, E.M.; Johnson, C.; Rechsteiner, C.; Moir, M.; Leong, D.; Feldmann, J.

2007-01-01

Speciation of trialkylated arsenic compunds in natural gas, pressurized and stable condensate samples from the same gas well was performed using (Cryotrapping) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry. The major species in all phases investigated was found to be trimethylarsine with a highest concentration of 17.8 ng/L (As) in the gas phase and 33.2 μg/L (As) in the stable condensate phase. The highest amount of trimethylarsine (121 μg/L (As)) was found in the pressurized condensate, along with trace amounts of non-identified higher alkylated arsines. Volatile arsenic species in natural gas and its related products cause concern with regards to environment, safety, occupational health and gas processing. Therefore, interest lies in a fast and simple field method for the determination of volatile arsenicals. Here, we use simple liquid and solid sorption techniques, namely absorption in silver nitrate solution and adsorption on silver nitrate impregnated silica gel tubes followed by total arsenic determination as a promising tool for field monitoring of volatile arsenicals in natural gas and gas condensates. Preliminary results obtained for the sorption-based methods show that around 70% of the arsenic is determined with these methods in comparison to volatile arsenic determination using GC-ICP-MS. Furthermore, an inter-laboratory- and inter-method comparison was performed using silver nitrate impregnated silica tubes on 14 different gas samples with concentrations varying from below 1 to 1000 μg As/m 3 natural gas. The results obtained from the two laboratories differ in a range of 10 to 60%, but agree within the order of magnitude, which is satisfactory for our purposes

Phase transitions of W condensation for the universe with finite fermion density

International Nuclear Information System (INIS)

Kalashnikov, O.K.; Perez Rojas, H.; Institute of Cybernetics, Mathematics and Physics, Cuban Academy of Sciences, Havana, Cuba)

1989-01-01

The phase diagrams of W condensation are established in the electroweak theory with a finite fermion density under conditions of neutral and electric charge conservation. We found for the universe with a zero neutral charge density that the W condensate occurs at any small fermion density ρ. This appears at first near the point of symmetry restoration. This condensate exists only in the finite-temperature region and evaporates completely or partially, when the temperature goes to zero

Gravitational effects of condensate dark matter on compact stellar objects

International Nuclear Information System (INIS)

Li, X.Y.; Wang, F.Y.; Cheng, K.S.

2012-01-01

We study the gravitational effect of non-self-annihilating dark matter on compact stellar objects. The self-interaction of condensate dark matter can give high accretion rate of dark matter onto stars. Phase transition to condensation state takes place when the dark matter density exceeds the critical value. A compact degenerate dark matter core is developed and alter the structure and stability of the stellar objects. Condensate dark matter admixed neutron stars is studied through the two-fluid TOV equation. The existence of condensate dark matter deforms the mass-radius relation of neutron stars and lower their maximum baryonic masses and radii. The possible effects on the Gamma-ray Burst rate in high redshift are discussed

A simple modelling of mass diffusion effects on condensation with noncondensable gases for the CATHARE Code

Energy Technology Data Exchange (ETDEWEB)

Coste, P.; Bestion, D. [Commissariat a l Energie Atomique, Grenoble (France)

1995-09-01

This paper presents a simple modelling of mass diffusion effects on condensation. In presence of noncondensable gases, the mass diffusion near the interface is modelled using the heat and mass transfer analogy and requires normally an iterative procedure to calculate the interface temperature. Simplifications of the model and of the solution procedure are used without important degradation of the predictions. The model is assessed on experimental data for both film condensation in vertical tubes and direct contact condensation in horizontal tubes, including air-steam, Nitrogen-steam and Helium-steam data. It is implemented in the Cathare code, a french system code for nuclear reactor thermal hydraulics developed by CEA, EDF, and FRAMATOME.

Flows of a Vapor due to Phase Change Processes at the Condensed Phases with Temperature Fields as their Internal Structures

National Research Council Canada - National Science Library

Onishi, Yoshimoto; Ooshida, Takeshi

2005-01-01

Transient to steady motions of a vapor caused by the evaporation and condensation processes occurring at the condensed phases placed in parallel have been studied based on the Boltzmann equation of BGK type...

Sub-shot-noise phase sensitivity with a Bose-Einstein condensate Mach-Zehnder interferometer

International Nuclear Information System (INIS)

Pezze, L.; Smerzi, A.; Collins, L.A.; Berman, G.P.; Bishop, A.R.

2005-01-01

Bose-Einstein condensates (BEC), with their coherence properties, have attracted wide interest for their possible application to ultraprecise interferometry and ultraweak force sensors. Since condensates, unlike photons, are interacting, they may permit the realization of specific quantum states needed as input of an interferometer to approach the Heisenberg limit, the supposed lower bound to precision phase measurements. To this end, we study the sensitivity to external weak perturbations of a representative matter-wave Mach-Zehnder interferometer whose input are two Bose-Einstein condensates created by splitting a single condensate in two parts. The interferometric phase sensitivity depends on the specific quantum state created with the two condensates, and, therefore, on the time scale of the splitting process. We identify three different regimes, characterized by a phase sensitivity Δθ scaling with the total number of condensate particles N as (i) the standard quantum limit Δθ∼1/N 1/2 (ii) the sub shot-noise Δθ∼1/N 3/4 , and the (iii) the Heisenberg limit Δθ∼1/N. However, in a realistic dynamical BEC splitting, the 1/N limit requires a long adiabaticity time scale, which is hardly reachable experimentally. On the other hand, the sub-shot-noise sensitivity Δθ∼1/N 3/4 can be reached in a realistic experimental setting. We also show that the 1/N 3/4 scaling is a rigorous upper bound in the limit N→∞, while keeping constant all different parameters of the bosonic Mach-Zehnder interferometer

Recommendations for the presentation of infrared absorption spectra in data collections condensed phases

CERN Document Server

Becker, E D

2013-01-01

Recommendations for the Presentation of Infrared Absorption Spectra in Data Collections-A. Condensed Phases presents the recommendations related to the infrared spectra of condensed phase materials that are proposed for permanent retention in data collections. These recommendations are based on two reports published by the Coblentz Society. This book emphasizes the three levels of quality evaluation for infrared spectra as designated by the Coblentz Society, including critically defined physical data, research quality analytical spectra, and approved analytical spectra. This text discusses the

Organic condensation: a vital link connecting aerosol formation to cloud condensation nuclei (CCN) concentrations

Science.gov (United States)

Riipinen, I.; Pierce, J. R.; Yli-Juuti, T.; Nieminen, T.; Häkkinen, S.; Ehn, M.; Junninen, H.; Lehtipalo, K.; Petäjä, T.; Slowik, J.; Chang, R.; Shantz, N. C.; Abbatt, J.; Leaitch, W. R.; Kerminen, V.-M.; Worsnop, D. R.; Pandis, S. N.; Donahue, N. M.; Kulmala, M.

2011-04-01

Atmospheric aerosol particles influence global climate as well as impair air quality through their effects on atmospheric visibility and human health. Ultrafine (<100 nm) particles often dominate aerosol numbers, and nucleation of atmospheric vapors is an important source of these particles. To have climatic relevance, however, the freshly nucleated particles need to grow in size. We combine observations from two continental sites (Egbert, Canada and Hyytiälä, Finland) to show that condensation of organic vapors is a crucial factor governing the lifetimes and climatic importance of the smallest atmospheric particles. We model the observed ultrafine aerosol growth with a simplified scheme approximating the condensing species as a mixture of effectively non-volatile and semi-volatile species, demonstrate that state-of-the-art organic gas-particle partitioning models fail to reproduce the observations, and propose a modeling approach that is consistent with the measurements. We find that roughly half of the mass of the condensing mass needs to be distributed proportional to the aerosol surface area (thus implying that the condensation is governed by gas-phase concentration rather than the equilibrium vapour pressure) to explain the observed aerosol growth. We demonstrate the large sensitivity of predicted number concentrations of cloud condensation nuclei (CCN) to these interactions between organic vapors and the smallest atmospheric nanoparticles - highlighting the need for representing this process in global climate models.

Wetting phase transition of two segregated Bose–Einstein condensates restricted by a hard wall

Energy Technology Data Exchange (ETDEWEB)

Thu, Nguyen Van [Department of Physics, Hanoi Pedagogical University No. 2, Hanoi (Viet Nam); Phat, Tran Huu [Vietnam Atomic Energy Commission, 59 Ly Thuong Kiet, Hanoi (Viet Nam); Song, Pham The, E-mail: thesong80@icloud.com [Tay Bac University, Son La (Viet Nam)

2016-04-01

Highlights: • System of two segregated Bose–Einstein condensates limited by a wall is studied. • Double-parabola approximation is applied to Gross–Pitaevskii theory. • Interface tension and wetting phase diagram are established. - Abstract: The wetting phase transition in the system of two segregated Bose–Einstein condensates (BECs) restricted by a hard wall is studied by means of the double-parabola approximation (DPA) applied to the Gross–Pitaevskii (GP) theory. We found the interfacial tension and the wetting phase diagram which depend weakly on the spatial restriction.

Fast atom bombardment mass spectrometry of condensed tannin sulfonate derivatives

Science.gov (United States)

J.J. Karchesy; L.Y. Foo; Richard W. Hemingway; E. Barofsky; D.F. Barofsky

1989-01-01

Condensed tannin sulfonate derivatives were studied by fast atom bombardment mass spectrometry (FAB-MS) to assess the feasibility of using this technique for determining molecular weight and structural information about these compounds. Both positive- and negative-ion spectra provided useful data with regard to molecular weight, cation species present, and presence of...

The Condensation effect on the two-phase flow stability

International Nuclear Information System (INIS)

Abdou Mohamed, Hesham Nagah

2005-01-01

A one-dimensional analytical model has been developed to be used for the linear analysis of density-wave oscillations in a parallel heated channel and a natural circulation loop.The heater and the riser sections are divided into a single-phase and a two-phase region.The two-phase region is represented by the drift-flux model. The model accounts for aphasic slip and subcooled boiling.The localized friction at the heater and the riser exit is treated considering the two-phase mixture.Also the effects of the condensation in the riser and the change in the system pressure have been studied.The exact equation for the heated channel and the total loop pressure drop is perturbed around the steady state.he stability characteristics of the heated channel and the loop are investigated using the Root finding method criterion.The results are summarized on instability maps in the plane of subcooled boiling number vs. phase change number (i.e., inlet subcooling vs. heater heat flux).The predictions of the model are compared with experimental results published in open literature. The results show that, the treatment effect of localized friction in two-phase mixtures stabilizes the system and improves the agreement of the calculations with the experimental results.For a parallel heated channel, the results indicate a more stable system with high inlet restriction, low outlet restriction, and high inlet velocity. And for a natural circulation loop, an increase in the inlet restriction broadened the range of the continuous circulation mode and stabilized the system, a decrease in the exit restriction or the liquid charging level shifted to the right the range of the continuous circulation mode and stabilized the system and an increase in the riser condensation shifted to the right the range of the continuous circulation mode and stabilized the system.The results show that the model agrees well with the available experimental data. In particular, the results show the significance of

Temperature-Dependent Change of Packing Structure of Condensed-Phase in a Micro-Phase Separated Langmuir Monolayer Studied by Grazing-Incidence X-ray Diffraction

Energy Technology Data Exchange (ETDEWEB)

Iimura, Ken-ichi [Department of Applied Chemisty, Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Utsunomiya (Japan); Kato, Teiji [Department of Applied Chemisty, Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya 321-8585, Utsunomiya (Japan); Brezesinski, Gerald [Max-Planck Instutite of Colloids and Interfaces, Research Campus Golm, D-14476 Potsdam (Germany)

2007-10-15

Packing structure of condensed-phase in a binary mixed Langmuir monolayer of behenic acid (C22) and perfluoro-2,5,8-trimethyl-3,6,9-trioxadodecanoic acid (PFPE) on a cadmium acetate aqueous solution was studied by grazing incidence X-ray diffraction (GIXD) as a function of the subphase temperature. The measurements were made during temperature scan at a fixed molecular area to explain the morphological change of the condensed-phase domains due to a thermal treatment reported previously. Analysis of GIXD data implies that the condensed-phase domains are composed of only the C22 molecules perpendicularly oriented and very closely packed in a centered rectangular unit cell with orthorhombic distortion at low temperatures. As the temperature increases the area occupied by molecule increases, and above 25 deg. C the lattice becomes disordered, which would allow morphological transformation of the condensed-phase domains. The process of packing structure change is almost reversible except for non-equilibrium phases observed for the monolayer spread at a low temperature, 5.5 deg. C.

Temperature-Dependent Change of Packing Structure of Condensed-Phase in a Micro-Phase Separated Langmuir Monolayer Studied by Grazing-Incidence X-ray Diffraction

International Nuclear Information System (INIS)

Iimura, Ken-ichi; Kato, Teiji; Brezesinski, Gerald

2007-01-01

Packing structure of condensed-phase in a binary mixed Langmuir monolayer of behenic acid (C22) and perfluoro-2,5,8-trimethyl-3,6,9-trioxadodecanoic acid (PFPE) on a cadmium acetate aqueous solution was studied by grazing incidence X-ray diffraction (GIXD) as a function of the subphase temperature. The measurements were made during temperature scan at a fixed molecular area to explain the morphological change of the condensed-phase domains due to a thermal treatment reported previously. Analysis of GIXD data implies that the condensed-phase domains are composed of only the C22 molecules perpendicularly oriented and very closely packed in a centered rectangular unit cell with orthorhombic distortion at low temperatures. As the temperature increases the area occupied by molecule increases, and above 25 deg. C the lattice becomes disordered, which would allow morphological transformation of the condensed-phase domains. The process of packing structure change is almost reversible except for non-equilibrium phases observed for the monolayer spread at a low temperature, 5.5 deg. C

Revisiting shape selectivity in liquid chromatography for polycyclic aromatic hydrocarbons (PAHs) - six-ring and seven-ring Cata-condensed PAH isomers of molecular mass 328 Da and 378 Da.

Science.gov (United States)

Oña-Ruales, Jorge O; Sander, Lane C; Wilson, Walter B; Wise, Stephen A

2018-01-01

The relationship of reversed-phase liquid chromatography (RPLC) retention on a polymeric C 18 stationary phase and the shape of polycyclic aromatic hydrocarbons (PAHs) was investigated for three-ring to seven-ring cata-condensed isomers. We report the first RPLC separation for six-ring and seven-ring cata-condensed PAH isomers. Correlations of LC retention and shape parameters (length-to-breath ratio, L/B and thickness, T) were investigated for 2 three-ring isomers (molecular mass 178 Da), 5 four-ring isomers (molecular mass 228 Da), 11 five-ring isomers (molecular mass 278 Da), 17 six-ring isomers (molecular mass 328 Da), and 20 seven-ring isomers (molecular mass 378 Da). Significant linear correlations were found for all isomer groups (r = 0.71 to 0.94). Nonplanarity of the PAH isomers was found to influence retention (i.e., nonplanar isomers eluting earlier than expected based on L/B) and linear correlations of retention vs. T for isomer groups containing nonplanar isomers were significant (r = 0.71 to 0.86). Graphical abstract.

Condensation and dissociation rates for gas phase metal clusters from molecular dynamics trajectory calculations

Science.gov (United States)

Yang, Huan; Goudeli, Eirini; Hogan, Christopher J.

2018-04-01

In gas phase synthesis systems, clusters form and grow via condensation, in which a monomer binds to an existing cluster. While a hard-sphere equation is frequently used to predict the condensation rate coefficient, this equation neglects the influences of potential interactions and cluster internal energy on the condensation process. Here, we present a collision rate theory-molecular dynamics simulation approach to calculate condensation probabilities and condensation rate coefficients. We use this approach to examine atomic condensation onto 6-56-atom Au and Mg clusters. The probability of condensation depends upon the initial relative velocity (v) between atom and cluster and the initial impact parameter (b). In all cases, there is a well-defined region of b-v space where condensation is highly probable, and outside of which the condensation probability drops to zero. For Au clusters with more than 10 atoms, we find that at gas temperatures in the 300-1200 K range, the condensation rate coefficient exceeds the hard-sphere rate coefficient by a factor of 1.5-2.0. Conversely, for Au clusters with 10 or fewer atoms and for 14- and 28-atom Mg clusters, as cluster equilibration temperature increases, the condensation rate coefficient drops to values below the hard-sphere rate coefficient. Calculations also yield the self-dissociation rate coefficient, which is found to vary considerably with gas temperature. Finally, calculations results reveal that grazing (high b) atom-cluster collisions at elevated velocity (>1000 m s-1) can result in the colliding atom rebounding (bounce) from the cluster surface or binding while another atom dissociates (replacement). The presented method can be applied in developing rate equations to predict material formation and growth rates in vapor phase systems.

Numerical simulation of gas-liquid two-phase flow behavior with condensation heat transfer

International Nuclear Information System (INIS)

Takamori, Kazuhide; Murase, Michio; Baba, Yoshikazu; Aihara, Tsuyoshi.

1995-01-01

In this study, condensation heat transfer experiments were performed in order to verify a condensation heat transfer model coupled with a three-dimensional two-phase flow analysis. In the heat transfer model, the liquid film flow rate on the heat transfer tubes was calculated by a mass balance equation and the liquid film thickness was calculated from the liquid film flow rate using Nusselt's laminar flow model and Fujii's equation for steam velocity effect. In the experiments, 112 horizontal staggered tubes with an outer diameter of 16 mm and length of 0.55 m were used. Steam and spray water were supplied to the test section, and inlet quality was controlled by the spray water flow rate. The temperature was 100degC and the pressure was 0.1 MPa. The overall heat transfer coefficients were measured for inlet quality of 13-100%. From parameter calculations for the falling liquid film ratio from the upper tubes to the lower tubes, the calculated overall heat transfer coefficients agreed with the data to within ±5% at the falling liquid film ratio of 0.7. (author)

Summer Research Institute Interfacial and Condensed Phase Chemical Physics

Energy Technology Data Exchange (ETDEWEB)

Barlow, Stephan E.

2004-10-01

Pacific Northwest National Laboratory (PNNL) hosted its first annual Summer Research Institute in Interfacial and Condensed Phase Chemical Physics from May through September 2004. During this period, fourteen PNNL scientists hosted sixteen young scientists from eleven different universities. Of the sixteen participants, fourteen were graduate students; one was transitioning to graduate school; and one was a university faculty member.

Influence of Capillary Condensation Effects on Mass Transport through Porous Membranes

Czech Academy of Sciences Publication Activity Database

Uchytil, Petr; Petričkovič, Roman; Thomas, S.; Siedel-Morgenstern, A.

2003-01-01

Roč. 33, č. 3 (2003), s. 273-281 ISSN 1383-5866 R&D Projects: GA ČR GA104/01/0945 Institutional research plan: CEZ:AV0Z4072921 Keywords : capillary condensation * mass transport * gas separation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.355, year: 2003

Mass and heat transfers in injecting-condensers; Transfert de masse et de chaleur dans les injecteurs-condenseurs

Energy Technology Data Exchange (ETDEWEB)

Mikasser, S.

2004-02-15

This study develops a physic and thermodynamic investigation of the condensing-injector that allow understanding the assumption of operating and the various physics phenomena intervening. Then, an experimental study concerning the small size condensing-injector was proposed. Lastly, the modelling of the flows were approached in two forms: a total modelling 0D of the condensing-injector and a modelling 1D of the mixing chamber. Thus, tree analytical formulations were employed for distinct flow patterns in the mixing chamber. The first part (heterogeneous flow) is a two-phase flow model based on a system in 6 equations of transport coupled with an equation of the witness fraction. The second part (scattered flow) resumes the homogeneous mode that composed of 3 equations of transport. The occurrence of shock phenomena is possible in the throat of the mixing chamber; so the analytical formulation of the condensation shock is described according to conditions shock that based on the balance equations. All these models are validated using the experimental results. (author)

Flue gas condensation in oxyfuel power plants. Heat- and mass transfer measurements and experimental validation of an efficient condensation concept; Rauchgaskondensation in Oxyfuel-Kraftwerken. Waerme- und Stoffuebergangsmessungen sowie experimentelle Validierung eines effizienten Kondensationskonzepts

Energy Technology Data Exchange (ETDEWEB)

Raindl, Markus

2010-12-06

Condensation of a steam-inert gas mixture in an Oxyfuel condenser differs significantly from condensation of pure steam: condenser pressure and rest gas content increase dramatically, heat- and mass transfer coefficients are lower and oversaturation of the steam-inert gas mixture yields to fog formation. In the context of this thesis, therefore, at first the optimal ranges of working parameters for Oxyfuel processes calculated. In the following some heat flux measurements were carried out on a horizontal, crossflow pipe to validate various heat- and mass transfer theories. Building on these results a new, efficient condensation concept was developed to reduce fog formation. The final results of the measurements with a laboratory model show great performance regarding fog reduction and condensation efficiency. (orig.)

A condensed-mass advection based model for the simulation of liquid polar stratospheric clouds

Directory of Open Access Journals (Sweden)

D. Lowe

2003-01-01

Full Text Available We present a condensed-mass advection based model (MADVEC designed to simulate the condensation/evaporation of liquid polar stratospheric cloud (PSC particles. A (Eulerian-in-radius discretization scheme is used, making the model suitable for use in global or mesoscale chemistry and transport models (CTMs. The mass advection equations are solved using an adaption of the weighted average flux (WAF scheme. We validate the numerical scheme using an analytical solution for multicomponent aerosols. The physics of the model are tested using a test case designed by Meilinger et al. (1995. The results from this test corroborate the composition gradients across the size distribution under rapid cooling conditions that were reported in earlier studies.

Condensation of atmospheric moisture from tropical maritime air masses as a freshwater resource.

Science.gov (United States)

Gerard, R D; Worzel, J L

1967-09-15

A method is proposed whereby potable water may be obtained by condensing moisture from the atmosphere in suitable seashore or island areas. Deep, cold, offshore seawater is used as a source of cold and is pumped to condensers set up on shore to intercept the flow of highly humid, tropical, maritime air masses. This air, when cooled, condenses moisture, which is conducted away and stored for use as a water supply. Windmill-driven generators would supply low-cost power for the operation. Side benefits are derived by using the nutritious deep water to support aquiculture in nearby lagoons or to enhance the productivity of the outfall area. Additional benefits are derived from the condenser as an air-conditioning device for nearby residents. The islands of the Caribbean are used as an example of a location in the trade-winds belt where nearly optimum conditions for the operation of this system can be found.

Study on condensation of biomass pyrolysis gas by spray bio-oil droplets

Energy Technology Data Exchange (ETDEWEB)

Xie, Kun; Cheng, Wen-Long [University of Science and Technology of China (China)], email: wlcheng@ustc.edu.cn; Chen, Jing [Anhui Electric Power Design Institute (China); Shi, Wen-Jing [Anhui Heli Co., Ltd (China)

2011-07-01

This is a study of bio-oil generated by fast pyrolysis; a biomass feedstock is heated to pyrolyze at a rapid rate, the gas pyrolyzed is then condensed rapidly. The interesting result is a potential alternative fuel oil. An analysis was made of the effects of the initial pyrolysis gas temperatures, the initial bio-oil droplets temperatures and diameters, and the flow ratio of the gas and the liquid droplets on the heat and mass transfer between the gas and the liquid droplets. A few criterion equations were achieved with respect to the spray condenser. This paper established the gas-liquid phase equilibrium of an aqueous multi-composition system and the spray condensation model coupling heat and mass transfer. Model calculation and analysis showed that: spray condensation can effectively cool the high-temperature pyrolysis gas quickly; with gas liquid flowing, mass transfer rate reduces; and the relationship of gas and liquid flow ratio can achieve good accuracy.

Chiral density wave versus pion condensation at finite density and zero temperature

Science.gov (United States)

Andersen, Jens O.; Kneschke, Patrick

2018-04-01

The quark-meson model is often used as a low-energy effective model for QCD to study the chiral transition at finite temperature T , baryon chemical potential μB , and isospin chemical potential μI . We determine the parameters of the model by matching the meson and quark masses, as well as the pion decay constant to their physical values using the on shell (OS) and modified minimal subtraction (MS ¯ ) schemes. In this paper, the existence of different phases at zero temperature is studied. In particular, we investigate the competition between an inhomogeneous chiral condensate and a homogeneous pion condensate. For the inhomogeneity, we use a chiral-density wave ansatz. For a sigma mass of 600 MeV, we find that an inhomogeneous chiral condensate exists only for pion masses below approximately 37 MeV. We also show that due to our parameter fixing, the onset of pion condensation takes place exactly at μIc=1/2 mπ in accordance with exact results.

Separate effects tests for GOTHIC condensation and evaporative heat transfer models

International Nuclear Information System (INIS)

George, T.L.; Singh, A.

1994-01-01

The GOTHIC computer program, under development at EPRI/NAI, is a general purpose thermal hydraulics computer program for design, licensing, safety and operating analysis of nuclear containments and other confinement buildings. The code solves a nine equation model for three dimensional multiphase flow with separate mass, momentum and energy equations for vapor, liquid and drop phases. The vapor phase can be a gas mixture of steam and non-condensing gases. The phase balance equations are coupled by mechanistic and empirical models for interface mass, energy and momentum transfer that cover the entire flow regime from bubbly flow to film/drop flow. A variety of heat transfer correlations are available to model the fluid coupling to active and passive solid conductors. This paper focuses on the application of GOTHIC to two separate effects tests; condensation heat transfer on a vertical flat plate with varying bulk velocity, steam concentration and temperature, and evaporative heat transfer from a hot pool to a dry (superheated) atmosphere. Comparisons with experimental data is included for both tests. Results show the validity of two condensation heat transfer correlations as incorporated into GOTHIC and the interfacial heat and mass transfer models for the range of the experimental test conditions. Comparisons are also made for lumped versus multidimensional modeling for buoyancy controlled flow with evaporative heat transfer. (author). 13 refs., 1 tab., 10 figs

Separate effects tests for GOTHIC condensation and evaporative heat transfer models

International Nuclear Information System (INIS)

George, T.L.; Singh, A.

1996-01-01

The GOTHIC computer program, under development at NAI for EPRI, is a general purpose thermal hydraulics computer program for design, licensing, safety and operating analysis of nuclear containments and other confinement buildings. The code solves a nine-equation model for three-dimensional multiphase flow with separate mass, momentum and energy equations for vapor, liquid and drop phases. The vapor phase can be a gas mixture of steam and non-condensing gases. The phase balance equations are coupled by mechanistic and empirical models for interface mass, energy and momentum transfer that cover the entire flow regime from bubbly flow to film-drop flow. A variety of heat transfer correlations are available to model the fluid coupling to active and passive solid conductors. This paper focuses on the application of GOTHIC to two separate effects tests: condensation heat transfer on a vertical flat plate with varying bulk velocity, steam concentration and temperature, and evaporative heat transfer from a hot pool to a dry (superheated) atmosphere. Comparisons with experimental data are included for both tests. Results show the validity of two condensation heat transfer correlations as incorporated into GOTHIC and the interfacial heat and mass transfer models for the range of the experimental test conditions. Comparisons are also made for lumped vs. multidimensional modeling for buoyancy-controlled flow with evaporative heat transfer. (orig.)

Phase collapse and revival of a 1-mode Bose-Einstein condensate induced by an off-resonant optical probe field and superselection rules

Science.gov (United States)

Arruda, L. G. E.; Prataviera, G. A.; de Oliveira, M. C.

2018-02-01

Phase collapse and revival for Bose-Einstein condensates are nonlinear phenomena appearing due to atomic collisions. While it has been observed in a general setting involving many modes, for one-mode condensates its occurrence is forbidden by the particle number superselection rule (SSR), which arises because there is no phase reference available. We consider a single mode atomic Bose-Einstein condensate interacting with an off-resonant optical probe field. We show that the condensate phase revival time is dependent on the atom-light interaction, allowing optical control on the atomic collapse and revival dynamics. Incoherent effects over the condensate phase are included by considering a continuous photo-detection over the probe field. We consider conditioned and unconditioned photo-counting events and verify that no extra control upon the condensate is achieved by the probe photo-detection, while further inference of the atomic system statistics is allowed leading to a useful test of the SSR on particle number and its imposition on the kind of physical condensate state.

Phase zone plates as condensers for the Gottingen scanning x-ray microscope

International Nuclear Information System (INIS)

Hilkenbach, R.; Thieme

1987-01-01

With the Gottingen scanning x-ray microscope the synchrotron source is image by x-ray optics into a monochromatic small scan spot, through which a specimen can be moved. Hereby one part of the optics, the condenser zone plate and a pinhole, works as a linear monochromator in the wavelength region of λ = 2.36 nm to λ = 4.5 nm. The efficiency of such a condenser should be as high as possible to minimize the loss of radiation. Phase zone plates have a four times higher efficiency in the first order of diffraction than amplitude zone plates. Two condenser zone plates, KZP4 and KZP5, have been constructed so that they are well suited for the use in the scanning microscope. These zone plates have been made holographically by superposing two wavefronts of laser light in an specific designed optical arrangement and exposing the zone plate structure into a photoresist. Using reactive ion etching (RIE) the structure has been transformed into Germanium. The thickness of the zone plate has been chosen to show at λ = 2.36 nm a phase effect. The efficiency has been measured at the Berliner Elektronenspeircherring Gesellschaft fur Synchrotronstrahlung m.b.H., Berlin

Analysis and comparison of biomass pyrolysis/gasification condensates: Final report

Energy Technology Data Exchange (ETDEWEB)

Elliott, D.C.

1986-06-01

This report provides results of chemical and physical analysis of condensates from eleven biomass gasification and pyrolysis systems. The samples were representative of the various reactor configurations being researched within the Department of Energy, Biomass Thermochemical Conversion program. The condensates included tar phases and aqueous phases. The analyses included gross compositional analysis (elemental analysis, ash, moisture), physical characterization (pour point, viscosity, density, heat of combustion, distillation), specific chemical analysis (gas chromatography/mass spectrometry, infrared spectrophotometry, proton and carbon-13 nuclear magnetic resonance spectrometry) and biological activity (Ames assay and mouse skin tumorigenicity tests). These results are the first step of a longer term program to determine the properties, handling requirements, and utility of the condensates recovered from biomass gasification and pyrolysis. The analytical data demonstrates the wide range of chemical composition of the organics recovered in the condensates and suggests a direct relationship between operating temperature and chemical composition of the condensates. A continuous pathway of thermal degradation of the tar components as a function of temperature is proposed. Variations in the chemical composition of the organic components in the tars are reflected in the physical properties of tars and phase stability in relation to water in the condensate. The biological activity appears to be limited to the tars produced at high temperatures. 56 refs., 25 figs., 21 tabs.

Anisotropic properties of phase separation in two-component dipolar Bose-Einstein condensates

Science.gov (United States)

Wang, Wei; Li, Jinbin

2018-03-01

Using Crank-Nicolson method, we calculate ground state wave functions of two-component dipolar Bose-Einstein condensates (BECs) and show that, due to dipole-dipole interaction (DDI), the condensate mixture displays anisotropic phase separation. The effects of DDI, inter-component s-wave scattering, strength of trap potential and particle numbers on the density profiles are investigated. Three types of two-component profiles are present, first cigar, along z-axis and concentric torus, second pancake (or blood cell), in xy-plane, and two non-uniform ellipsoid, separated by the pancake and third two dumbbell shapes.

Topological susceptibility and chiral condensate with Nf=2+1+1 dynamical flavors of maximally twisted mass fermions

International Nuclear Information System (INIS)

Cichy, K.

2012-03-01

We study the 'spectral projector' method for the computation of the chiral condensate and the topological susceptibility, using N f =2+1+1 dynamical flavors of maximally twisted mass Wilson fermions. In particular, we perform a study of the quark mass dependence of the chiral condensate Σ and topological susceptibility χ top in the range 270 MeV π top in the quenched approximation where we match the lattice spacing to the N f =2+1+1 dynamical simulations. Using the Kaon, η and η' meson masses computed on the N f =2+1+1 ensembles, we then perform a preliminary test of the Witten-Veneziano relation.

Studies of cluster-assembled materials: From gas phase to condensed phase

Science.gov (United States)

Gao, Lin

Clusters, defined as "a number of similar things that occur together" in Webster's dictionary, has different meanings depending on the given subject. To physicists and chemists, the word cluster means "a group of atoms or molecules formed by interactions ranging from very weak van der Waals interactions to strong ionic bonds." Unlike molecules, which are made by nature and are stable under ambient conditions, clusters discovered in a laboratory are often metastable. Molecules have specific stoichiometry, whereas the cluster's composition can usually be altered atom by atom. Thus, clusters can be taken as intrinsically "artificial molecules" with considerably more tunabilities in their properties. Research into the relative stability and instability of clusters has in recent years become a very active research area, especially following the study by Khanna and Castleman that first suggested that by varying size and composition, clusters can expand the periodic table to the 3 rd-dimension; that is, clusters can mimic the chemistry of atoms and may, therefore, be used as the building blocks of new materials. The discovery of Met-Cars has drawn worldwide interests and has been actively investigated by researchers from a variety of fields, including physics, chemistry and material science. However, the unsuccessful search for a solvent capable of isolating Met-Cars has impeded progress in characterizing the material in the condensed state and, hence, limited its potential applications as a novel nanoscale material. An alternative method involving the deposition of mass-gated species and the subsequent structural investigation via Transmission Electron Microscopy (TEM) has been employed. With particularly interesting results, soft-landed deposits of zirconium Met-Cars were found to form a face-centered-cubic (FCC) structure with a lattice parameter ˜ 15A. The production of Met-Cars is conducted with the direct laser vaporization (DLV) of metal/graphite composite pellets

Goldstone boson condensation and effects of the axial anomaly in color superconductivity

Energy Technology Data Exchange (ETDEWEB)

Basler, Hannes Gregor Steffen

2011-01-12

One of the central objects of interest in high energy physics is the phase diagram of strongly interacting matter, the behavior of quarks and gluons in dependence of temperature and chemical potential. At very high densities and low temperatures it is expected that quarks form a superconductor, the so-called color superconductor. Such a color superconductor might be realized in the inner core of a neutron star. To study the phase structure of a color superconductor under neutron star conditions the Nambu-Jona-Lasinio model is used. The diquark condensates appearing in a color superconductor may break the original symmetries and give rise to Goldstone bosons. In this work we study the possible condensation of these Goldstone bosons. On the level of diquark condensates the condensation of Goldstone bosons is realized by a rotation of scalar into pseudoscalar diquark condensates. The phase diagram is studied, including pseudoscalar diquark condensates, for several different values of the lepton number chemical potential. The masses and thereby the condensation of the Goldstone bosons is effected by a six-point interaction that breaks the axial U(1) symmetry. Usually this six-point interaction is implemented in the NJL model in such a way that is does not effect the diquark sector. This can be fixed by adding an second six-point interaction term to the NJL Lagrangian. The coupling strength of this new interaction term has a great influence on the phase digram. In this context also the effect on the chiral phase transition is studied. (orig.)

Phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles: Specific characteristics of the condensed phases.

Science.gov (United States)

Vollhardt, D

2015-08-01

For understanding the role of amide containing amphiphiles in inherently complex biological processes, monolayers at the air-water interface are used as simple biomimetic model systems. The specific characteristics of the condensed phases and phase transition in insoluble and adsorbed monolayers of amide amphiphiles are surveyed to highlight the effect of the chemical structure of the amide amphiphiles on the interfacial interactions in model monolayers. The mesoscopic topography and/or two-dimensional lattice structures of selected amino acid amphiphiles, amphiphilic N-alkylaldonamide, amide amphiphiles with specific tailored headgroups, such as amide amphiphiles based on derivatized ethanolamine, e.g. acylethanolamines (NAEs) and N-,O-diacylethanolamines (DAEs) are presented. Special attention is devoted the dominance of N,O-diacylated ethanolamine in mixed amphiphilic acid amide monolayers. The evidence that a first order phase transition can occur in adsorption layers and that condensed phase domains of mesoscopic scale can be formed in adsorption layers was first obtained on the basis of the experimental characteristics of a tailored amide amphiphile. New thermodynamic and kinetic concepts for the theoretical description of the characteristics of amide amphiphile's monolayers were developed. In particular, the equation of state for Langmuir monolayers generalized for the case that one, two or more phase transitions occur, and the new theory for phase transition in adsorbed monolayers are experimentally confirmed at first by amide amphiphile monolayers. Despite the significant progress made towards the understanding the model systems, these model studies are still limited to transfer the gained knowledge to biological systems where the fundamental physical principles are operative in the same way. The study of biomimetic systems, as described in this review, is only a first step in this direction. Copyright © 2014 Elsevier B.V. All rights reserved.

Measurement of liquid-liquid equilibria for condensate + glycol and condensate + glycol + water systems

DEFF Research Database (Denmark)

Riaz, Muhammad; Kontogeorgis, Georgios; Stenby, Erling Halfdan

2011-01-01

,2-ethanediol (MEG) + condensate and MEG + water + condensate systems at temperatures from (275 to 323) K at atmospheric pressure. The condensate used in this work is a stabilized natural gas condensate from an offshore field in the North Sea. Compositional analysis of the natural gas condensate was carried out...... by gas chromatography, and detailed separation of individual condensate's components has been carried out. Approximately 85 peaks eluting before nonane were identified by their retention time. Peak areas were converted to mass fraction using 1-heptene as an internal standard. The components were divided...... into boiling range groups from hexane to nonane. Paraffinic (P), naphthenic (N), and aromatic (A) distributions were obtained for the boiling point fractions up to nonane. The average molar mass and the overall density of the condensate were measured experimentally. For the mutual solubility of MEG...

Condensation heat transfer and pressure drop of R-410A in a 7.0 mm O.D. microfin tube at low mass fluxes

Science.gov (United States)

Kim, Nae-Hyun

2016-12-01

R-410A condensation heat transfer and pressure drop data are provided for a 7.0 mm O.D. microfin tube at low mass fluxes (50-250 kg/m2 s). The heat transfer coefficient of the microfin tube shows a minimum behavior with the mass flux. At a low mass flux, where flow pattern is stratified, condensation induced by surface tension by microfins overwhelms condensation induced by shear, and the heat transfer coefficient decreases as mass flux increases. At a high mass flux, where flow pattern is annular, condensation induced by shear governs the heat transfer, and the heat transfer coefficient increases as mass flux increases. The pressure drop of the microfin tube is larger than that of the smooth tube at the annular flow regime. On the contrary, the pressure drop of the smooth tube is larger than that of the microfin tube at the stratified flow regime.

Exotic phases in neutron stars

International Nuclear Information System (INIS)

Li, A.; Burgio, G.F.; Lombardo, U.; Peng, G.X.

2008-01-01

The appearance of exotic phases in neutron stars is studied. The possible transition from hadron to quark phase is studied within the density dependent mass quark model, and the kaon condensation within the Nelson and Kaplan model. In both cases a microscopic approach is adopted for dense hadron matter. From the study of the possible coexistence between the two phases it is found that the hybrid phase may strongly hinder the onset of kaon condensation. (author)

Analysis and comparison of biomass pyrolysis/gasification condensates: an interim report

Energy Technology Data Exchange (ETDEWEB)

Elliott, D.C.

1985-09-01

This report provides results of chemical and physical analysis of condensates from eleven biomass gasification and pyrolysis systems. The analyses were performed in order to provide more detailed data concerning these condensates for the different process research groups and to allow a determination of the differences in properties of the condensates as a function of reactor environment. The samples were representative of the various reactor configurations being researched within the Department of Energy, Biomass Thermochemical Conversion program. The condensates included tar phases, aqueous phases and, in some cases, both phases depending on the output of the particular reactor system. The analyses included gross compositional analysis (elemental analysis, ash, moisture), physical characterization (pour point, viscosity, density, heat of combustion, distillation), specific chemical analysis (gas chromatography/mass spectrometry, infrared spectrophotometry, proton and carbon-13 nuclear magnetic resonance spectrometry) and biological activity (Ames assay). The analytical data demonstrate the wide range of chemical composition of the organics recovered in the condensates and suggests a direct relationship between operating temperature and chemical composition of the condensates. A continuous pathway of thermal degradation of the tar components as a function of temperature is proposed. Variations in the chemical composition of the organic components in the tars are reflected in the physical properties of tars and phase stability in relation to water in the condensate. The biological activity appears to be limited to the tars produced at high temperatures as a result of formation of polycyclic aromatic hydrocarbons in high concentrations. 55 refs., 13 figs., 6 tabs.

Comparing the mechanism of water condensation and evaporation in glassy aerosol.

Science.gov (United States)

Bones, David L; Reid, Jonathan P; Lienhard, Daniel M; Krieger, Ulrich K

2012-07-17

Atmospheric models generally assume that aerosol particles are in equilibrium with the surrounding gas phase. However, recent observations that secondary organic aerosols can exist in a glassy state have highlighted the need to more fully understand the kinetic limitations that may control water partitioning in ambient particles. Here, we explore the influence of slow water diffusion in the condensed aerosol phase on the rates of both condensation and evaporation, demonstrating that significant inhibition in mass transfer occurs for ultraviscous aerosol, not just for glassy aerosol. Using coarse mode (3-4 um radius) ternary sucrose/sodium chloride/aqueous droplets as a proxy for multicomponent ambient aerosol, we demonstrate that the timescale for particle equilibration correlates with bulk viscosity and can be ≫10(3) s. Extrapolation of these timescales to particle sizes in the accumulation mode (e.g., approximately 100 nm) by applying the Stokes-Einstein equation suggests that the kinetic limitations imposed on mass transfer of water by slow bulk phase diffusion must be more fully investigated for atmospheric aerosol. Measurements have been made on particles covering a range in dynamic viscosity from  10(13) Pa s. We also retrieve the radial inhomogeneities apparent in particle composition during condensation and evaporation and contrast the dynamics of slow dissolution of a viscous core into a labile shell during condensation with the slow percolation of water during evaporation through a more homogeneous viscous particle bulk.

Condensation induced non-condensable accumulation in a non-vented horizontal pipe connected with an elbow and a vertical pipe

International Nuclear Information System (INIS)

Stevanovic, V.D.; Stosic, Z.V.; Stoll, U.

2005-01-01

In this paper the radiolytic gases (hydrogen and oxygen) accumulation is investigated numerically for the pipe geometry consisting of a horizontal pipe closed at one end, and connected via a downward directed elbow with a vertical pipe open at its bottom end. This configuration is a typical part of many pipeline systems or measuring lines. The steam inside the pipes is condensed due to heat losses to the surrounding atmosphere, the condensate is drained and the concentration of the remaining noncondensable radiolytic gases is increased. Three dimensional numerical simulations are performed with the thermal-hydraulic and physico-chemical code HELIO, especially developed for the simulation and analyses of radiolytic gases accumulation in pipelines. The HELIO code model is based on the mass, momentum and energy conservation equations for the gas mixture and wall condensate film flow, as well as on the transport equations for non-condensable diffusion and convection. At the liquid film surface, the phases are coupled through the no-slip velocity condition and the mass transfer due to steam condensation and non-condensable absorption and degassing. Obtained numerical results show the gas mixture and condensate liquid film flow fields. In case of here analyzed geometry, the gas mixture circulates in the elbow and the horizontal pipe due to buoyancy forces induced by concentration and related density differences. The circulation flow prevents the formation of the radiolytic gases concentration front. The non-condensable radiolytic gases are transported from the pipe through the open end by the mechanisms of diffusion and convection. The analyzed geometry is the same as in case of venting pipe mounted on the steam pipeline. The results are of practical importance since they show that radiolytic gases accumulation does not occur in the geometry of the venting pipes. (authors)

Structures of the particles of the condensed dispersed phase in solid fuel combustion products plasma

International Nuclear Information System (INIS)

Samaryan, A.A.; Chernyshev, A.V.; Nefedov, A.P.; Petrov, O.F.; Fortov, V.E.; Mikhailov, Yu.M.; Mintsev, V.B.

2000-01-01

The results of experimental investigations of a type of dusty plasma which has been least studied--the plasma of solid fuel combustion products--were presented. Experiments to determine the parameters of the plasma of the combustion products of synthetic solid fuels with various compositions together with simultaneous diagnostics of the degree of ordering of the structures of the particles of the dispersed condensed phase were performed. The measurements showed that the charge composition of the plasma of the solid fuels combustion products depends strongly on the easily ionized alkali-metal impurities which are always present in synthetic fuel in one or another amount. An ordered arrangement of the particles of a condensed dispersed phase in structures that form in a boundary region between the high-temperature and condensation zones was observed for samples of aluminum-coated solid fuels with a low content of alkali-metal impurities

Statistical quantization of GUT models and phase diagrams of W condensation for the Universe with finite fermion density

International Nuclear Information System (INIS)

Kalashnikov, O.K.; Razumov, L.V.; Perez Rojas, H.

1990-01-01

The problems of statistical quantization for grand-unified-theory models are studied using as an example the Weinberg-Salam model with finite fermion density under the conditions of neutral and electric charge conservation. The relativistic R γ gauge with an arbitrary parameter is used and the one-loop effective potential together with its extremum equations are found. We demonstrate (and this is our main result) that the thermodynamic potential obtained from the effective one, after the mass shell for ξ is used, remains gauge dependent if all temperature ranges (not only the leading high-temperature terms) are considered. The contradiction detected within the calculational scheme is eliminated after the redefinition of the model studied is made with the aid of the terms which are proportional to the ''non-Abelian'' chemical potential and equal to zero identically when the unitary gauge is fixed. The phase diagrams of the W condensation are established and all their peculiarities are displayed. We found for the universe with a zero neutral charge density that the W condensate occurs at any small fermion density ρ and appears at first near the point of symmetry restoration. For all ρ≠0 this condensate exists only in the finite-temperature domain and evaporates completely or partially when T goes to zero

Heat transfer degradation during condensation of non-azeotropic mixtures

Science.gov (United States)

Azzolin, M.; Berto, A.; Bortolin, S.; Del, D., Col

2017-11-01

International organizations call for a reduction of the HFCs production and utilizations in the next years. Binary or ternary blends of hydroflourocarbons (HFCs) and hydrofluoroolefins (HFOs) are emerging as possible substitutes for high Global Warming Potential (GWP) fluids currently employed in some refrigeration and air-conditioning applications. In some cases, these mixtures are non-azeotropic and thus, during phase-change at constant pressure, they present a temperature glide that, for some blends, can be higher than 10 K. Such temperature variation during phase change could lead to a better matching between the refrigerant and the water temperature profiles in a condenser, thus reducing the exergy losses associated with the heat transfer process. Nevertheless, the additional mass transfer resistance which occurs during the phase change of zeotropic mixtures leads to a heat transfer degradation. Therefore, the design of a condenser working with a zeotropic mixture poses the problem of how to extend the correlations developed for pure fluids to the case of condensation of mixtures. Experimental data taken are very helpful in the assessment of design procedures. In the present paper, heat transfer coefficients have been measured during condensation of zeotropic mixtures of HFC and HFO fluids. Tests have been carried out in the test rig available at the Two Phase Heat Transfer Lab of University of Padova. During the condensation tests, the heat is subtracted from the mixture by using cold water and the heat transfer coefficient is obtained from the measurement of the heat flux on the water side, the direct measurements of the wall temperature and saturation temperature. Tests have been performed at 40°C mean saturation temperature. The present experimental database is used to assess predictive correlations for condensation of mixtures, providing valuable information on the applicability of available models.

Heat-transfer enhancement of two-phase closed thermosyphon using a novel cross-flow condenser

Science.gov (United States)

Aghel, Babak; Rahimi, Masoud; Almasi, Saeed

2017-03-01

The present study reports the heat-transfer performance of a two-phase closed thermosyphon (TPCT) equipped with a novel condenser. Distillated water was used as working fluid, with a volumetric liquid filling ratio of 75 %. An increase in heat flux was used to measure the response of the TPCT, including variations in temperature distribution, thermal resistance, average temperature of each section of TPCT and overall thermal difference. Results show that for various power inputs from 71 to 960 W, the TPCT with the novel condenser had a lower wall-temperature difference between the evaporator and condenser sections than did the unmodified TPCT. Given the experimental data for heat-transfer performance, it was found that the thermal resistance in the TPCT equipped with the proposed condenser was between 10 and 17 % lower than in the one without.

Numerical Study of Condensation Heat Exchanger Design in a Subcooled Pool: Correlation Investigation

International Nuclear Information System (INIS)

Lee, Hee Joon; Ju, Yun Jae; Kang, Han Ok; Lee, Tae Ho; Park, Cheon Tae

2012-01-01

Generally the condensation heat exchanger has higher heat transfer coefficient compared to the single phase heat exchanger, so has been widely applied to the cooling systems of energy plant. Recently vertical or horizontal type condensation heat exchangers are being studied for the application to secondary passive cooling system of nuclear plants. Lee and Lee investigated the existing condensation correlation to the experiment for heat exchanger in saturated pool. They concluded Traviss' correlation showed most satisfactory results for the heat transfer coefficient and mass flow rate in a saturated water pool. In this study, a thermal sizing program of vertical condensation heat exchanger to design, TSCON(Thermal Sizing of CONdenser) was validated with the existing experimental data of condensation heat exchanger in a subcooled pool for pure steam condensation

Efficient, Long-Life Biocidal Condenser, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity. Condensing surfaces must be...

Large scale electronic structure calculations in the study of the condensed phase

NARCIS (Netherlands)

van Dam, H.J.J.; Guest, M.F.; Sherwood, P.; Thomas, J.M.H.; van Lenthe, J.H.; van Lingen, J.N.J.; Bailey, C.L.; Bush, I.J.

2006-01-01

We consider the role that large-scale electronic structure computations can now play in the modelling of the condensed phase. To structure our analysis, we consider four distict ways in which today's scientific targets can be re-scoped to take advantage of advances in computing resources: 1. time to

A Facile, Choline Chloride/Urea Catalyzed Solid Phase Synthesis of Coumarins via Knoevenagel Condensation

Directory of Open Access Journals (Sweden)

Hosanagara N. Harishkumar

2011-01-01

Full Text Available The influence of choline chloride/urea ionic liquid in solid phase on the Knoevenagel condensation is demonstrated. The active methylene compounds such as meldrum’s acid, diethylmalonate, ethyl cyanoacetate, dimethylmalonate, were efficiently condensed with various salicylaldehydes in presence of choline chloride/urea ionic liquid without using any solvents or additional catalyst. The reaction is remarkably facile because of the air and water stability of the catalyst, and needs no special precautions. The reactions were completed within 1hr with excellent yields (95%. The products formed were sufficiently pure, and can be easily recovered. The use of ionic liquid choline chloride/urea in solid phase offered several significant advantages such as low cost, greater selectivity and easy isolation of products.

Examination of transient characteristics of two-phase natural circulation within a Freon-113 boiling/condensation loop

International Nuclear Information System (INIS)

Tanimoto, K.; Ishii, M.

1998-01-01

Transient characteristics of two-phase natural circulation within a Freon-113 loop with a large condenser have been examined mainly focused on the flashing phenomenon. General behavior was described and parametric studies were performed. The items observed were the period and duration of flashing, peak flow rate, amount of flow carryover per flashing, lowest-peak liquid level within the condenser, and the peak void distribution in the riser section. The parameters considered were the heater power input, valve friction at the heater inlet (simulating the loopwise friction), condenser cooling, degree of subcooling at the heater inlet, and the heat loss to the surroundings. As a whole, the heater power input, valve friction, and the rate of condenser cooling played important roles in flashing while the other effects being marginal. In general, the flow appeared to be more unstable with the larger condensing surface which causes the condensation-induced flashing. (orig.)

Numerical investigation of convective condensation with the presence of non-condensable gases in a vertical tube

Energy Technology Data Exchange (ETDEWEB)

Fu, Wen [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Li, Xiaowei, E-mail: lixiaowei@tsinghua.edu.cn [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wu, Xinxin [Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Corradini, Michael L. [Department of Engineering Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2016-02-15

Highlights: • Gas mixture convective condensation in vertical tubes were simulated using FLUENT code. • The simulation results matched well with experimental data. • The detailed velocity field and species distribution were investigated. • The suction factors predicted by CFD models were compared with the classical correlations. • The effects of air and helium on steam condensation were compared. - Abstract: Steam condensation is degraded when non-condensable gases are present. Convective condensation of steam–air mixture and steam–helium mixture in vertical tubes were simulated using the CFD code FLUENT. The condensation process was modeled by defining source terms for the mass, momentum, species and energy conservation equations. Several cases with various steam mass fractions were simulated, the results matched well with the experimental data. Detailed velocity field and species distribution were investigated. The radial velocity was clearly represented, and the suction effect was modeled, which needs to be accounted for when using the heat and mass transfer analogy theory. The Nusselt and Sherwood numbers predicted by CFD models were compared with the classical correlations, and the suction effects were analyzed. The suction effect is proportional to steam mass fraction, while the suction factor is little affected by the Reynolds number. For forced convection flow in this work, the buoyant force can be neglected, so the larger diffusion coefficient of steam–helium mixture would improve the steam condensation compared to steam–air mixture. The condensation mass fluxes of steam–helium mixture and steam–air mixture are almost the same at relatively high steam inlet molar fraction (≥90%).

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.)

Method of measuring interface area of activated carbons in condensed phase

Science.gov (United States)

Dmitriyev, D. S.; Agafonov, D. V.; Kiseleva, E. A.; Mikryukova, M. A.

2018-01-01

In this work, we investigated the correlation between the heat of wetting of super-capacitor electrode material (activated carbon) with condensed phases (electrolytes based on homologous series of phosphoric acid esters) and the capacity of the supercapacitor. The surface area of the electrode-electrolyte interface was calculated according to the obtained correlations using the conventional formula for calculating the capacitance of a capacitor.

Numerical analysis for simulation of condensing vapor bubble using CFD-ACE+

International Nuclear Information System (INIS)

Goyal, P.; Dutta, Anu; Singh, R.K.

2014-01-01

The motion of bubbles is very complex. They may be subject to break-up or coalescence and may appear to move with a spiraling, zigzagging or rocking behavior. Recently, many studies have been carried out to numerically simulate the rising bubble in various conditions by using VOF approach. However, all the above studies were limited to adiabatic bubble where heat and mass transfer between the phases were not considered. In the present work, an attempt was made to capture the behaviour of condensing bubble flowing in a channel, by using commercial CFD code CFD-ACE+ through VOF model. A User-Defined Function was developed to simulate interfacial heat and mass transfer during condensation. The effect of condensation on bubble behavior was analyzed by comparing the behavior of condensing bubble with that of adiabatic bubble. For validation of CFD-ACE UDF of bubble condensation, a comparison was made with the literature quoted experimental data and it agreed well. Through this work an emphasis was put on VOF module along with the development of an UDF for bubble condensation in CFD-ACE+ code. This theoretical study is motivated by the future CFD application and the intent to investigate the capabilities of the CFD-ACE+ package. (author)

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.

Gluon-ghost condensate of mass dimension 2 in the Curci-Ferrari gauge

International Nuclear Information System (INIS)

Dudal, D.; Verschelde, H.; Lemes, V.E.R.; Sarandy, M.S.; Sorella, S.P.; Picariello, M.

2003-01-01

The effective potential for an on-shell BRST invariant gluon-ghost condensate of mass dimension 2 in the Curci-Ferrari gauge in SU(N) Yang-Mills is analysed by combining the local composite operator technique with the algebraic renormalization. We pay attention to the gauge parameter independence of the vacuum energy obtained in the considered framework and discuss the Landau gauge as an interesting special case

Polariton condensation phase diagram in wide-band-gap planar microcavities: GaN versus ZnO

Science.gov (United States)

Jamadi, O.; Réveret, F.; Mallet, E.; Disseix, P.; Médard, F.; Mihailovic, M.; Solnyshkov, D.; Malpuech, G.; Leymarie, J.; Lafosse, X.; Bouchoule, S.; Li, F.; Leroux, M.; Semond, F.; Zuniga-Perez, J.

2016-03-01

The polariton condensation phase diagram is compared in GaN and ZnO microcavities grown on mesa-patterned silicon substrate. Owing to a common platform, these microcavities share similar photonic properties with large quality factors and low photonic disorder, which makes it possible to determine the optimal spot diameter and to realize a thorough phase diagram study. Both systems have been investigated under the same experimental conditions. The experimental results and the subsequent analysis reveal clearly that longitudinal optical phonons have no influence in the thermodynamic region of the condensation phase diagram, while they allow a strong (slight) decrease of the polariton lasing threshold in the trade-off zone (kinetic region). Phase diagrams are compared with numerical simulations using Boltzmann equations, and are in satisfactory agreement. A lower polariton lasing threshold has been measured at low temperature in the ZnO microcavity, as is expected due to a larger Rabi splitting. This study highlights polariton relaxation mechanisms and their importance in polariton lasing.

Exact mquark ≠ 0 condensates in QCD1+1(NC → ∞)

International Nuclear Information System (INIS)

Burkardt, M.

1994-01-01

In the limit of an infinite number of colors, we derive an analytic expression for the quark condensation in QCD 1+1 as a function of the quark mass and the gauge coupling constant. For zero quark mass, a nonvanishing quark condensate is obtained. Nevertheless, we prove that there is no phase transition as a function of the quark mass. It is furthermore shown that the expansion of left-angle 0|bar ψψ|0 right-angle in the gauge coupling has zero radius of convergence but that the perturbation series is Borel summable with finite radius of convergence. The nonanalytic behavior m q →0 ∼ -N C √G 2 can only be obtained by summing the perturbation series to infinite order

Nonlinear optical response in condensed phases : A microscopic theory using the multipolar Hamiltonian

NARCIS (Netherlands)

Knoester, Jasper; Mukamel, Shaul

1990-01-01

A general scheme is presented for calculating the nonlinear optical response in condensed phases that provides a unified picture of excitons, polaritons, retardation, and local-field effects in crystals and in disordered systems. A fully microscopic starting point is taken by considering the

Computation of the chiral condensate using Nf=2 and Nf=2+1+1 dynamical flavors of twisted mass fermions

International Nuclear Information System (INIS)

Cichy, K.; Jansen, K.; Shindler, A.; Forschungszentrum Juelich; Forschungszentrum Juelich

2013-12-01

We apply the spectral projector method, recently introduced by Giusti and Luescher, to compute the chiral condensate using N f =2 and N f =2+1+1 dynamical flavors of maximally twisted mass fermions. We present our results for several quark masses at three different lattice spacings which allows us to perform the chiral and continuum extrapolations. In addition we report our analysis on the O(a) improvement of the chiral condensate for twisted mass fermions. We also study the effect of the dynamical strange and charm quarks by comparing our results for N f =2 and N f =2+1+1 dynamical flavors.

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.

Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

Directory of Open Access Journals (Sweden)

Azhar Hashmi

2016-09-01

Full Text Available The hydroxypivaldehyde (HPA precursor intermediate for the synthesis of neopentyl glycol (NPG is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

Cross-Aldol condensation of isobutyraldehyde and formaldehyde using phase transfer catalyst

OpenAIRE

Azhar Hashmi

2016-01-01

The hydroxypivaldehyde (HPA) precursor intermediate for the synthesis of neopentyl glycol (NPG) is prepared by novel cross Aldol condensation of isobutyraldehyde and formaldehyde at 20 °C using benzyltrimethylammonium hydroxide, a basic phase transfer catalyst. A feed mole ratio of 1.1:1.0:0.04 (isobutyraldehyde:formaldehyde:benzyltrimethylammonium hydroxide) afforded hydroxypivaldehyde as white solid in almost quantitative yield with ∼100% selectivity.

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

Quantum phase transition of Bose-Einstein condensates on a nonlinear ring lattice

International Nuclear Information System (INIS)

Zhou Zhengwei; Zhang Shaoliang; Zhou Xiangfa; Guo Guangcan; Zhou Xingxiang; Pu Han

2011-01-01

We study the phase transitions in a one-dimensional Bose-Einstein condensate on a ring whose atomic scattering length is modulated periodically along the ring. By using a modified Bogoliubov method to treat such a nonlinear lattice in the mean-field approximation, we find that the phase transitions are of different orders when the modulation period is 2 and greater than 2. We further perform a full quantum mechanical treatment based on the time-evolving block decimation algorithm which confirms the mean-field results and reveals interesting quantum behavior of the system. Our studies yield important knowledge of competing mechanisms behind the phase transitions and the quantum nature of this system.

Can hydrodynamic contact line paradox be solved by evaporation-condensation?

Science.gov (United States)

Janeček, V; Doumenc, F; Guerrier, B; Nikolayev, V S

2015-12-15

We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation-condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid-liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact line singularity. The liquid mass is conserved: evaporation existing on a part of the meniscus and condensation occurring over another part compensate exactly each other. However, numerical estimations carried out for three common fluids (ethanol, water and glycerol) at the ambient conditions show that the characteristic length scales are tiny. Copyright © 2015 Elsevier Inc. All rights reserved.

2005 Annual Report Summer Research Institute Interfacial and Condensed Phase Chemical Physics

Energy Technology Data Exchange (ETDEWEB)

Barlow, Stephan E.

2005-11-15

The Pacific Northwest National Laboratory (PNNL) hosted its second annual Summer Research Institute in Interfacial and Condensed Phase Chemical Physics from May through September 2005. During this period, sixteen PNNL scientists hosted fourteen young scientists from eleven different universities. Of the fourteen participants, twelve were graduate students; one was a postdoctoral fellow; and one was a university faculty member.

Antikaon condensation in neutron stars by a new nonlinear mean-field model

CERN Document Server

Miyazaki, K

2005-01-01

We have investigated both the K^- and \\bar{K}^0 condensations in beta-equilibrated neutron star (NS) matter using the relativistic mean-field model with the renormalized meson-baryon coupling constants. Adopting the antikaon optical potential of -120MeV, our model predicts the K^- condensation as the second-order phase transition inside the neutron star of maximum mass, while the deeper potential than -160MeV is ruled out. This is in contrast to the result of the density-dependent hadron field theory. Our model also predicts remarkable softening of the equation of state by the \\bar{K}^0 condensation at high densities. Although this is contrasted with the result of the nonlinear Walecka model, only the K^- condensation can be formed in NSs.

Intermolecular interactions in the condensed phase: Evaluation of semi-empirical quantum mechanical methods.

Science.gov (United States)

Christensen, Anders S; Kromann, Jimmy C; Jensen, Jan H; Cui, Qiang

2017-10-28

To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy in solution is computed via a thermodynamic cycle that integrates dimer binding energy in the gas phase at the coupled cluster level and solute-solvent interaction with density functional theory; the estimated uncertainty of such calculated interaction energy is ±1.5 kcal/mol. The dataset is used to benchmark the performance of a set of semi-empirical quantum mechanical (SQM) methods that include DFTB3-D3, DFTB3/CPE-D3, OM2-D3, PM6-D3, PM6-D3H+, and PM7 as well as the HF-3c method. We find that while all tested SQM methods tend to underestimate binding energies in the gas phase with a root-mean-squared error (RMSE) of 2-5 kcal/mol, they overestimate binding energies in the solution phase with an RMSE of 3-4 kcal/mol, with the exception of DFTB3/CPE-D3 and OM2-D3, for which the systematic deviation is less pronounced. In addition, we find that HF-3c systematically overestimates binding energies in both gas and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need to be treated in a balanced fashion.

Intermolecular interactions in the condensed phase: Evaluation of semi-empirical quantum mechanical methods

Science.gov (United States)

Christensen, Anders S.; Kromann, Jimmy C.; Jensen, Jan H.; Cui, Qiang

2017-10-01

To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy in solution is computed via a thermodynamic cycle that integrates dimer binding energy in the gas phase at the coupled cluster level and solute-solvent interaction with density functional theory; the estimated uncertainty of such calculated interaction energy is ±1.5 kcal/mol. The dataset is used to benchmark the performance of a set of semi-empirical quantum mechanical (SQM) methods that include DFTB3-D3, DFTB3/CPE-D3, OM2-D3, PM6-D3, PM6-D3H+, and PM7 as well as the HF-3c method. We find that while all tested SQM methods tend to underestimate binding energies in the gas phase with a root-mean-squared error (RMSE) of 2-5 kcal/mol, they overestimate binding energies in the solution phase with an RMSE of 3-4 kcal/mol, with the exception of DFTB3/CPE-D3 and OM2-D3, for which the systematic deviation is less pronounced. In addition, we find that HF-3c systematically overestimates binding energies in both gas and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need to be treated in a balanced fashion.

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

Vortex-induced phase slip dissipation in a torioidal Bose-Einstein condensate flowing through a barrier

Energy Technology Data Exchange (ETDEWEB)

Collins, Lee A [Los Alamos National Laboratory

2009-01-01

We study the phase slips superfluid dissipation mechanism with a BEC flowing through a repulsive barrier inside a torus. The barrier is adiabatically raised across the annulus while the condensate is flowing with a finite quantized angular momentum. We found that, at a critical height, a vortex reaches the barrier moving radially from the inner region to eventually circulate along the annulus. At a slightly higher barrier, an anti-vortex also enters into the annulus from the outward region. The vortex and anti-vortex decrease the total angular momentum by leaving behind their respective paths a 2{pi} phase slip. When they collide or orbit along the same loop, the condensate suffers a global 2{pi} phase slip and the total angular momentum decreases by one quantum. The analysis is based on numerical simulations of the dynamical Gross-Pitaevskii equation both in two- and three-dimensions, the latter with the experimental parameters of the torus trap recently created at the NIST institute.

Affleck-Dine baryogenesis, condensate fragmentation and gravitino dark matter in gauge-mediation with a large messenger mass

International Nuclear Information System (INIS)

Doddato, Francesca; McDonald, John

2011-01-01

We study the conditions for successful Affleck-Dine baryogenesis and the origin of gravitino dark matter in GMSB models. AD baryogenesis in GMSB models is ruled out by neutron star stability unless Q-balls are unstable and decay before nucleosynthesis. Unstable Q-balls can form if the messenger mass scale is larger than the flat-direction field Φ when the condensate fragments. We provide an example based on AD baryogenesis along a d = 6 flat direction for the case where m 3/2 ≈ 2GeV, as predicted by gravitino dark matter from Q-ball decay. Using a phenomenological GMSB potential which models the Φ dependence of the SUSY breaking terms, we numerically solve for the evolution of Φ and show that the messenger mass can be sufficiently close to the flat-direction field when the condensate fragments. We compute the corresponding reheating temperature and the baryonic charge of the condensate fragments and show that the charge is large enough to produce late-decaying Q-balls which can be the origin of gravitino dark matter

Aromaticity of benzene in condensed phases. A case of a benzene-water system

Science.gov (United States)

Zborowski, Krzysztof K.

2014-05-01

A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

Switching moving boundary models for two-phase flow evaporators and condensers

Science.gov (United States)

Bonilla, Javier; Dormido, Sebastián; Cellier, François E.

2015-03-01

The moving boundary method is an appealing approach for the design, testing and validation of advanced control schemes for evaporators and condensers. When it comes to advanced control strategies, not only accurate but fast dynamic models are required. Moving boundary models are fast low-order dynamic models, and they can describe the dynamic behavior with high accuracy. This paper presents a mathematical formulation based on physical principles for two-phase flow moving boundary evaporator and condenser models which support dynamic switching between all possible flow configurations. The models were implemented in a library using the equation-based object-oriented Modelica language. Several integrity tests in steady-state and transient predictions together with stability tests verified the models. Experimental data from a direct steam generation parabolic-trough solar thermal power plant is used to validate and compare the developed moving boundary models against finite volume models.

Theoretical and computational studies of non-equilibrium and non-statistical dynamics in the gas phase, in the condensed phase and at interfaces.

Science.gov (United States)

Spezia, Riccardo; Martínez-Nuñez, Emilio; Vazquez, Saulo; Hase, William L

2017-04-28

In this Introduction, we show the basic problems of non-statistical and non-equilibrium phenomena related to the papers collected in this themed issue. Over the past few years, significant advances in both computing power and development of theories have allowed the study of larger systems, increasing the time length of simulations and improving the quality of potential energy surfaces. In particular, the possibility of using quantum chemistry to calculate energies and forces 'on the fly' has paved the way to directly study chemical reactions. This has provided a valuable tool to explore molecular mechanisms at given temperatures and energies and to see whether these reactive trajectories follow statistical laws and/or minimum energy pathways. This themed issue collects different aspects of the problem and gives an overview of recent works and developments in different contexts, from the gas phase to the condensed phase to excited states.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).

Manipulation of a Bose-Einstein condensate by a time-averaged orbiting potential using phase jumps of the rotating field

NARCIS (Netherlands)

Cleary, P.W.; Hijmans, T.W.; Walraven, J.T.M.

2010-01-01

We report on the manipulation of the center-of-mass motion ("sloshing") of a Bose-Einstein condensate in a time-averaged orbiting potential (TOP) trap. We start with a condensate at rest in the center of a static trapping potential. When suddenly replacing the static trap with a TOP trap centered

Characterization of simultaneous heat and mass transfer phenomena for water vapour condensation on a solid surface in an abiotic environment--application to bioprocesses.

Science.gov (United States)

Tiwari, Akhilesh; Kondjoyan, Alain; Fontaine, Jean-Pierre

2012-07-01

The phenomenon of heat and mass transfer by condensation of water vapour from humid air involves several key concepts in aerobic bioreactors. The high performance of bioreactors results from optimised interactions between biological processes and multiphase heat and mass transfer. Indeed in various processes such as submerged fermenters and solid-state fermenters, gas/liquid transfer need to be well controlled, as it is involved at the microorganism interface and for the control of the global process. For the theoretical prediction of such phenomena, mathematical models require heat and mass transfer coefficients. To date, very few data have been validated concerning mass transfer coefficients from humid air inflows relevant to those bioprocesses. Our study focussed on the condensation process of water vapour and developed an experimental set-up and protocol to study the velocity profiles and the mass flux on a small size horizontal flat plate in controlled environmental conditions. A closed circuit wind tunnel facility was used to control the temperature, hygrometry and hydrodynamics of the flow. The temperature of the active surface was controlled and kept isothermal below the dew point to induce condensation, by the use of thermoelectricity. The experiments were performed at ambient temperature for a relative humidity between 35-65% and for a velocity of 1.0 ms⁻¹. The obtained data are analysed and compared to available theoretical calculations on condensation mass flux.

Non-Markovian response of ultrafast coherent electronic ring currents in chiral aromatic molecules in a condensed phase

International Nuclear Information System (INIS)

Mineo, H.; Lin, S. H.; Fujimura, Y.; Xu, J.; Xu, R. X.; Yan, Y. J.

2013-01-01

Results of a theoretical study on non-Markov response for femtosecond laser-driven coherent ring currents in chiral aromatic molecules embedded in a condensed phase are presented. Coherent ring currents are generated by coherent excitation of a pair of quasi-degenerated π-electronic excited states. The coherent electronic dynamical behaviors are strongly influenced by interactions between the electronic system and phonon bath in a condensed phase. Here, the bath correlation time is not instantaneous but should be taken to be a finite time in ultrashort time-resolved experiments. In such a case, Markov approximation breaks down. A hierarchical master equation approach for an improved semiclassical Drude dissipation model was adopted to examine the non-Markov effects on ultrafast coherent electronic ring currents of (P)-2,2 ′ -biphenol in a condensed phase. Time evolution of the coherent ring current derived in the hierarchical master equation approach was calculated and compared with those in the Drude model in the Markov approximation and in the static limit. The results show how non-Markovian behaviors in quantum beat signals of ring currents depend on the Drude bath damping constant. Effects of temperatures on ultrafast coherent electronic ring currents are also clarified

The Effect of Quark Mass and α-α Term on qq Condensation in QCD Vacuum

Institute of Scientific and Technical Information of China (English)

YANG Sheng-Dong; ZHOU Zhi-Ning; YANG Ze-Sen

2001-01-01

Beginning with the QCD Lagrangian in the global color symmetry model, we have derived a Hamiltonian including the lowest order current-current coupling. Taking instantaneous quadratic interaction kernel and using the Bogoliubov-Valatin transformation, we have got an effective Hamiltonian for computation. This Hamiltonian is similar to that introduced by Le Yaouanc et al., except that the α-α term has been considered here. We calculated the qq condensation in the BCS type of vacuum with quark mass and α-α term included. Our calculation shows that the value of qq condensation has increased by at least 10% with the α-α term included.``

2006 Annual Report Summer Research Institute Interfacial and Condensed Phase Chemical Physics

Energy Technology Data Exchange (ETDEWEB)

Avery, Nikki B.; Barlow, Stephan E.

2006-11-10

The Pacific Northwest National Laboratory (PNNL) hosted its third annual Summer Research Institute in Interfacial and Condensed Phase Chemical Physics from May through September 2006. During this period, twenty PNNL scientists hosted twenty-seven scientists from twenty-five different universities. Of the twenty-seven participants, one was a graduating senior; twenty-one were graduate students; one was a postdoctoral fellow; and four were university faculty members.

Dynamics of inhomogeneous chiral condensates

Science.gov (United States)

Carlomagno, Juan Pablo; Krein, Gastão; Kroff, Daniel; Peixoto, Thiago

2018-01-01

We study the dynamics of the formation of inhomogeneous chirally broken phases in the final stages of a heavy-ion collision, with particular interest on the time scales involved in the formation process. The study is conducted within the framework of a Ginzburg-Landau time evolution, driven by a free energy functional motivated by the Nambu-Jona-Lasinio model. Expansion of the medium is modeled by one-dimensional Bjorken flow and its effect on the formation of inhomogeneous condensates is investigated. We also use a free energy functional from a nonlocal Nambu-Jona-Lasinio model which predicts metastable phases that lead to long-lived inhomogeneous condensates before reaching an equilibrium phase with homogeneous condensates.

Coherent Control of Multiphoton Transitions in the Gas and Condensed Phases with Shaped Ultrashort Pulses

International Nuclear Information System (INIS)

Dantus, Marcos

2008-01-01

Controlling laser-molecule interactions has become an integral part of developing devices and applications in spectroscopy, microscopy, optical switching, micromachining and photochemistry. Coherent control of multiphoton transitions could bring a significant improvement of these methods. In microscopy, multi-photon transitions are used to activate different contrast agents and suppress background fluorescence; coherent control could generate selective probe excitation. In photochemistry, different dissociative states are accessed through two, three, or more photon transitions; coherent control could be used to select the reaction pathway and therefore the yield-specific products. For micromachining and processing a wide variety of materials, femtosecond lasers are now used routinely. Understanding the interactions between the intense femtosecond pulse and the material could lead to technologically important advances. Pulse shaping could then be used to optimize the desired outcome. The scope of our research program is to develop robust and efficient strategies to control nonlinear laser-matter interactions using ultrashort shaped pulses in gas and condensed phases. Our systematic research has led to significant developments in a number of areas relevant to the AMO Physics group at DOE, among them: generation of ultrashort phase shaped pulses, coherent control and manipulation of quantum mechanical states in gas and condensed phases, behavior of isolated molecules under intense laser fields, behavior of condensed phase matter under intense laser field and implications on micromachining with ultrashort pulses, coherent control of nanoparticles their surface plasmon waves and their nonlinear optical behavior, and observation of coherent Coulomb explosion processes at 10 16 W/cm 2 . In all, the research has resulted in 36 publications (five journal covers) and nine invention disclosures, five of which have continued on to patenting

2007 Annual Report Summer Research Institute Interfacial and Condensed Phase Chemical Physics

Energy Technology Data Exchange (ETDEWEB)

Beck, Kenneth M.

2007-10-31

The Pacific Northwest National Laboratory (PNNL) hosted its fourth annual Summer Research Institute in Interfacial and Condensed Phase Chemical Physics from April through September 2007. During this time, 21 PNNL scientists hosted 23 participants from 20 different universities. Of the 23 participants, 20 were graduate students, 1 was a postdoctoral fellow, and 2 were university faculty members. This report covers the essense of the program and the research the participants performed.

A study of the condensation of a high-velocity vapor jet on a coflowing turbulent liquid jet

Science.gov (United States)

Ovsiannikov, V. A.; Levin, A. A.

A method for the experimental determination of the local value of the heat transfer coefficient under conditions of jet condensation is proposed which employs a heat balance expression in differential form. The method is used in an experimental study of the heat transfer characteristics of the condensation of a high-velocity coaxial jet of a slightly superheated (3 percent) steam on a coflowing cylindrical turbulent water jet. In the experiment, the relative velocities reach hundreds of m/s; the temperature nonequilibrium of the phases is high, as is the steam flow mass density during the initial contact; heat transfer between the phases is significant. The results can be used as the basis for determining experimental criterial dependences for jet condensation.

An order-by-disorder process in the cyclic phase of spin-2 condensate with a weak magnetic field

International Nuclear Information System (INIS)

Zheng, Gong-Ping; Xu, Lei-Kuan; Qin, Shuai-Feng; Jian, Wen-Tian; Liang, J.-Q.

2013-01-01

We present in this paper a model study on the “order-by-disorder” process in the cyclic phase of spin-2 condensate, which forms a family of incommensurable, spiral degenerate ground states. On the basis of the ordering mechanism of entropic splitting, it is demonstrated that the energy corrections resulting from quantum fluctuations of disorder lift the accidental degeneracy of the cyclic configurations and thus lead to an eventual spiral order called the cyclic order. The order-by-disorder phenomenon is then realized even if the magnetic field exists. Finally, we show that our theoretic observations can be verified experimentally by direct detection of the cyclic order in the 87 Rb condensate of a spin-2 manifold with a weak magnetic field. -- Highlights: •A model for the order-by-disorder process in the cyclic phase of spin-2 condensate is presented. •The second-order quantum fluctuations of the mean-field states are studied. •The energy corrections lift the accidental degeneracy of the cyclic configurations. •The order-by-disorder phenomenon is realized even if a magnetic field exists. •The theoretic observations can be verified experimentally for 87 Rb condensate

Implementation of wall film condensation model to two-fluid model in component thermal hydraulic analysis code CUPID - 15237

International Nuclear Information System (INIS)

Lee, J.H.; Park, G.C.; Cho, H.K.

2015-01-01

In the containment of a nuclear reactor, the wall condensation occurs when containment cooling system and structures remove the mass and energy release and this phenomenon is of great importance to ensure containment integrity. If the phenomenon occurs in the presence of non-condensable gases, their accumulation near the condensate film leads to significant reduction in heat transfer during the condensation. This study aims at simulating the wall film condensation in the presence of non-condensable gas using CUPID, a computational multi-fluid dynamics code, which is developed by the Korea Atomic Energy Research Institute (KAERI) for the analysis of transient two-phase flows in nuclear reactor components. In order to simulate the wall film condensation in containment, the code requires a proper wall condensation model and liquid film model applicable to the analysis of the large scale system. In the present study, the liquid film model and wall film condensation model were implemented in the two-fluid model of CUPID. For the condensation simulation, a wall function approach with heat and mass transfer analogy was applied in order to save computational time without considerable refinement for the boundary layer. This paper presents the implemented wall film condensation model and then, introduces the simulation result using CUPID with the model for a conceptual condensation problem in a large system. (authors)

Gas condensate--raw material for producing liquid paraffin hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Aliyeva, R.B.; Alikishi-Zade, G.Yu.; Kuliyev, A.M.; Leonidov, A.N.; Pereverzev, A.N.

1980-01-01

The problem of efficient utilization of gas condensates as raw material for removal of a valuable product, liquid paraffins, is examined. A classification of gas condensates is given which is used as raw material for removing these hydrocarbons: gas condensate with high content of n-alkanes (25-40 mass percent), with average content (18-25 mass percent), with low content (12-18 mass percent), light weight fractions compositions, which do not contain fractions up to 200/sup 0/, and also, content ofless than 12% n-alkanes. Gas condensate I-III groups are 30% of the total reserve of gas condensate. Liquid paraffins hydrocarbons, produced from fractions of diesel fuel, which has been removed from Shatlyk gas condensate under conditions which simulate virtual processes of caramide deparaffinization meet all requirements without additional refining.

CFD Modeling of Wall Steam Condensation: Two-Phase Flow Approach versus Homogeneous Flow Approach

International Nuclear Information System (INIS)

Mimouni, S.; Mechitoua, N.; Foissac, A.; Hassanaly, M.; Ouraou, M.

2011-01-01

The present work is focused on the condensation heat transfer that plays a dominant role in many accident scenarios postulated to occur in the containment of nuclear reactors. The study compares a general multiphase approach implemented in NEPTUNE C FD with a homogeneous model, of widespread use for engineering studies, implemented in Code S aturne. The model implemented in NEPTUNE C FD assumes that liquid droplets form along the wall within nucleation sites. Vapor condensation on droplets makes them grow. Once the droplet diameter reaches a critical value, gravitational forces compensate surface tension force and then droplets slide over the wall and form a liquid film. This approach allows taking into account simultaneously the mechanical drift between the droplet and the gas, the heat and mass transfer on droplets in the core of the flow and the condensation/evaporation phenomena on the walls. As concern the homogeneous approach, the motion of the liquid film due to the gravitational forces is neglected, as well as the volume occupied by the liquid. Both condensation models and compressible procedures are validated and compared to experimental data provided by the TOSQAN ISP47 experiment (IRSN Saclay). Computational results compare favorably with experimental data, particularly for the Helium and steam volume fractions.

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

Condensing heat transfer following a loss-of-coolant accident

International Nuclear Information System (INIS)

Krotiuk, W.J.; Rubin, M.B.

1978-01-01

A new method for calculating the steam mass condensation energy removal rates on cold surfaces in contact with an air-steam mixture has been developed. This method is based on the principles of mass diffusion of steam from an area of high concentration to the condensing surface, which is an area of low steam concentration. This new method of calculating mass condensation has been programmed into the CONTEMPT-LT Mod 26 computer code, which calculates the pressure and temperature transients inside a light water reactor containment following a loss-of-coolant accident. The condensing heat transfer coefficient predicted by the mass diffusion method is compared to existing semi-empirical correlations and to the experimental results of the Carolinas Virginia Tube Reactor Containment natural decay test. Closer agreement with test results is shown in the calculation of containment pressure, temperature, and heat sink surface temperature using the mass diffusion condensation method than when using any existing semi-empirical correlation

The effect of non-condensable gas on direct contact condensation of steam/air mixture

International Nuclear Information System (INIS)

Lee, H. C.; Park, S. K.; Kim, M. H.

1998-01-01

To investigate the effects of noncondensable gas on the direct contact film condensation of vapor mixture, a series of experiments has been carried out. The rectangular duct inclined 87.deg. to the horizontal plane was used for this experiment. The average heat transfer coefficient of the steam-air mixture was obtained at the atmospheric pressure with four main parameters, air-mass fraction, vapor velocity, film Reynolds number,and the degree of water film subcooling having an influence on the condensation heat transfer coefficient. With the analysis on 88 cases of experiments, a correlation of the average Nusselt number for direct contact film condensation of steam-air mixture at a vertical wall proposed as functions of film Reynolds number, mixture Reynolds number, air mass fraction, and Jacob number. The average heat transfer coefficient for steam-air mixture condensation decreased significantly while air mass fraction increases with the same inlet mixture velocity and inlet film temperature. The average heat transfer coefficients also decreased with the degree of film subcooling increasing and were scarcely affected by film Reynolds number below the mixture Reynolds number about 30,000

Pionic atom as a probe of origin of the Hadron Mass. Quantitative evaluation of the chiral condensate in a nuclear medium

International Nuclear Information System (INIS)

Suzuki, Ken; Itahashi, Kenta; Hirenzaki, Satoru

2005-01-01

Spontaneous breaking of chiral symmetry is believed to be the mechanism which endows nucleus their large masses. The order parameter of the symmetry breaking is the chiral condensate, whose magnitude is predicted to decrease linearly as the nuclear density is increased. The reduction of quark condensate was quantitatively studied from recent precise measurement of deeply bound pionic 1s states on three tin (Sn) isotopes. We made use of the Gell-Mann-Oakes-Renner relation which connects the magnitude of quark-codensate to a pion decay constant, and then used the Tomozawa-Weinberg relation which relates the pion decay constant to an isovector strength of the pion-nucleus potential. The potential strength was determined by fitting the measured pionic 1s-state binding energies. The result shows that the quark-condensate strength is reduced by about 35% at normal nuclear density, compared with the ''vacuum'' value obtained from pionic hydrogen X-ray measurements. This is the first quantitative deduction of the quark condensate modification at finite nuclear density, and is an important step towards understanding the origin of hadron masses. (author)

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)

Numerical analyses of a water pool under loadings caused by a condensation induced water hammer

Energy Technology Data Exchange (ETDEWEB)

Timperi, A.; Paettikangas, T.; Calonius, K.; Tuunanen, J.; Poikolainen, J.; Saarenheimo, A. [VTT Industrial Systems (Finland)

2004-03-01

Three-dimensional simulations of a rapidly condensing steam bubble in a water pool have been performed by using the commercial computational fluid dynamics (CFD) code Star-CD. The condensing bubble was modelled by using a mass sink in a single-phase calculation. The pressure load on the wall of the pool was determined and transferred to the structural analyses code ABAQUS. The analyses were done for a test pool at Lappeenranta University of Technology. The structural integrity of the pool during steam experiments was investigated by assuming as a test load the rapid condensation of a steam bubble with a diameter of 20 cm. The mass sink for modelling the collapse of the bubble was deter-mined from the potential theory of incompressible fluid. The rapid condensation of the bubble within 25 ms initiated a strong condensation water hammer. The maximum amplitude of the pressure load on the pool wall was approximately 300 kPa. The loads caused by the high compression waves lasted only about 0.4 ms. The loadings caused by larger bubbles or more rapid collapse could not be calculated with the present method. (au)

Quark-antiquark condensates in the hadronic phase

International Nuclear Information System (INIS)

Tawfik, A.; Toublan, D.

2005-01-01

We use a hadron resonance gas model to calculate the quark-antiquark condensates for light (up and down) and strange quark flavors at finite temperatures and chemical potentials. At zero chemical potentials, we find that at the temperature where the light quark-antiquark condensates entirely vanish the strange quark-antiquark condensate still keeps a relatively large fraction of its value in the vacuum. This is in agreement with results obtained in lattice simulations and in chiral perturbation theory at finite temperature and zero chemical potentials. Furthermore, we find that this effect slowly disappears at larger baryon chemical potential. These results might have significant consequences for our understanding of QCD at finite temperatures and chemical potentials. Concretely, our results imply that there might be a domain of temperatures where chiral symmetry is restored for light quarks, but still broken for strange quark that persists at small chemical potentials. This might have practical consequences for heavy ion collision experiments

Refrigeration. Heat Transfer. Part I: Evaporators and Condensers

DEFF Research Database (Denmark)

Knudsen, Hans-Jørgen Høgaard

2002-01-01

The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation.......The note gives an introduction to heat transfer with phase shift. Pool Boiling, Flow Boiling, Condensation....

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.

Performance of a passive emergency heat removal system of advanced reactors in two-phase flow and with high concentration of non-condensable

International Nuclear Information System (INIS)

Macedo, Luiz Alberto

2008-01-01

The research and the development of passive emergency cooling systems are necessary for the new generation of thermo-nuclear systems. Some basic information on the operation of these systems require the research of some relative processes to the natural circulation, mainly in conditions of two-phase flow involving processes of condensation in the presence of non-condensable gases, because many found situations are new. The experimental facility called Bancada de Circulacao Natural (BCN) was used for the realization of tests with diverse concentrations of non-condensable and power levels. The non-condensable gas present in the circuit decreases the rate of heat transfer for the secondary of the heat exchanger, determining low efficiency of the heat exchanger. High concentration of non-condensable in the vapor condensation, determines negative pressure, and cause the inversion of the flow in the circuit. The initial concentration of non-condensable and the geometry of the circuit, in the inlet of the heat exchanger, determines the establishment of transitory with two-phase flow. The BCN was performed with the computational code of Analysis of Accidents and Thermal-Hydraulics RELAP5/MOD 3.3 and, the calculated values had been compared with the experimental data, presenting good agreement for small non-condensable concentrations. The values calculated for high concentrations of non-condensable had been satisfactory after the circuit to have reached the temperature of saturation in the electric heater. (author)

Performance of evaporative condensers

Energy Technology Data Exchange (ETDEWEB)

Ettouney, Hisham M.; El-Dessouky, Hisham T.; Bouhamra, Walid; Al-Azmi, Bader

2001-07-01

Experimental investigation is conducted to study the performance of evaporative condensers/coolers. The analysis includes development of correlations for the external heat transfer coefficient and the system efficiency. The evaporative condenser includes two finned-tube heat exchangers. The system is designed to allow for operation of a single condenser, two condensers in parallel, and two condensers in series. The analysis is performed as a function of the water-to-air mass flow rate ratio (L/G) and the steam temperature. Also, comparison is made between the performance of the evaporative condenser and same device as an air-cooled condenser. Analysis of the collected data shows that the system efficiency increases at lower L/G ratios and higher steam temperatures. The system efficiency for various configurations for the evaporative condenser varies between 97% and 99%. Lower efficiencies are obtained for the air-cooled condenser, with values between 88% and 92%. The highest efficiency is found for the two condensers in series, followed by two condensers in parallel and then the single condenser. The parallel condenser configuration can handle a larger amount of inlet steam and can provide the required system efficiency and degree of subcooling. The correlation for the system efficiency gives a simple tool for preliminary system design. The correlation developed for the external heat transfer coefficient is found to be consistent with the available literature data. (Author)

Entropy generation in a condenser and related correlations

Directory of Open Access Journals (Sweden)

Askowski Rafał

2015-06-01

Full Text Available The paper presents an analysis of relations describing entropy generation in a condenser of a steam unit. Connections between entropy generation, condenser ratio, and heat exchanger effectiveness, as well as relations implied by them are shown. Theoretical considerations allowed to determine limits of individual parameters which describe the condenser operation. Various relations for average temperature of the cold fluid were compared. All the proposed relations were verified against data obtained using a simulator and actual measurement data from a 200 MW unit condenser. Based on data from a simulator it was examined how the sum of entropy rates, steam condenser effectiveness, terminal temperature difference and condenser ratio vary with the change in the inlet cooling water temperature, mass flow rate of steam and the cooling water mass flow rate.

Fluid flow behaviour of gas-condensate and near-miscible fluids at the pore scale

Energy Technology Data Exchange (ETDEWEB)

Dawe, Richard A. [Department of Chemical Engineering, University of West Indies, St. Augustine (Trinidad and Tobago); Grattoni, Carlos A. [Department of Earth Science and Engineering, Imperial College, London, SW7 2BP (United Kingdom)

2007-02-15

Retrograde condensate reservoir behaviour is complex with much of the detailed mechanisms of the multiphase fluid transport and mass transfer between the phases within the porous matrix still speculative. Visual modelling of selected processes occurring at the pore level under known and controlled boundary conditions can give an insight to fluid displacements at the core scale and help the interpretation of production behaviour at reservoir scale. Visualisation of the pore scale two-phase flow mechanisms has been studied experimentally at low interfacial tensions, < 0.5 mN/m, using a partially miscible fluid system in glass visual micro models. As the interfacial tension decreases the balance between fluid-fluid forces (interfacial, spreading and viscous) and fluid-solid interactions (wettability and viscous interactions) changes. Data measurements in the laboratory, particularly relative permeability, will therefore always be difficult especially for condensate fluids just below their dew point. What is certain is that gas production from a gas-condensate leads to condensate dropout when pressure falls below the dew point, either within the wellbore or, more importantly, in the reservoir. This paper illustrates some pore scale physics, particularly interfacial phenomena at low interfacial tension, which has relevance to appreciating the flow of condensate fluids close to their dew point either near the wellbore (which affects well productivity) or deep inside the reservoir (which affects condensate recovery). (author)

Rotational symmetry breaking and topological phase transition in the exciton-polariton condensate of gapped 2D Dirac material

Science.gov (United States)

Lee, Ki Hoon; Lee, Changhee; Jeong, Jae-Seung; Min, Hongki; Chung, Suk Bum

For the quantum well in an optical microcavity, the interplay of the Coulomb interaction and the electron-photon coupling can lead to the emergence of bosonic quasiparticles consisting of the exciton and the cavity photon known as polariton, which can form the Bose-Einstein condensate above a threshold density. Additional physics due to the nontrivial Berry phase comes into play when the quantum well consists of the gapped Dirac material such as the transition metal dichalcogenide (TMD) MoS2 or WTe2. Specifically, in forming excitons, the electron-photon coupling from the optical selection rule due to the Berry phase competes against, rather than cooperates with, the Coulomb interaction. We find that this competition gives rise to the spontaneous breaking of the rotational symmetry in the polariton condensate and also drives topological phase transition, both novel features in polariton condensation. We also investigate the possible detection of this competition through photoluminescence. This work was supported in part by the Institute for Basic Science of Korea (IBS) under Grant IBS-R009-Y1 and by the National Research Foundation of Korea (NRF) under the Basic Science Research Program Grant No. 2015R1D1A1A01058071.

The Effect of Capillary Number on a Condensate Blockage in Gas Condensate Reservoirs

OpenAIRE

Saifon DAUNGKAEW; Alain C GRINGARTEN

2004-01-01

In the petroleum industry, gas condensate reservoirs are becoming more common as exploration targets. However, there is a lack of knowledge of the reservoir behaviour mainly due to its complexity in the near wellbore region, where two phases, i.e. reservoir gas and condensate coexist when the wellbore pressure drops below the dew point pressure. The condensation process causes a reduction of the gas productivity (1). It has been reported in the literature that there is an increasing gas mobil...

Computation of the chiral condensate using N{sub f}=2 and N{sub f}=2+1+1 dynamical flavors of twisted mass fermions

Energy Technology Data Exchange (ETDEWEB)

Cichy, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Garcia-Ramos, E. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany); Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Shindler, A. [Forschungszentrum Juelich (Germany). IAS; Forschungszentrum Juelich (Germany). IKP; Forschungszentrum Juelich (Germany). JCHP; Collaboration: European Twisted Mass Collaboration

2013-12-15

We apply the spectral projector method, recently introduced by Giusti and Luescher, to compute the chiral condensate using N{sub f}=2 and N{sub f}=2+1+1 dynamical flavors of maximally twisted mass fermions. We present our results for several quark masses at three different lattice spacings which allows us to perform the chiral and continuum extrapolations. In addition we report our analysis on the O(a) improvement of the chiral condensate for twisted mass fermions. We also 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 flavors.

Atomic-phase interference devices based on ring-shaped Bose-Einstein condensates: Two-ring case

International Nuclear Information System (INIS)

Anderson, B.P.; Dholakia, K.; Wright, E.M.

2003-01-01

We theoretically investigate the ground-state properties and quantum dynamics of a pair of adjacent ring-shaped Bose-Einstein condensates that are coupled via tunneling. This device, which is the analog of a symmetric superconducting quantum interference device, is the simplest version of what we term an atomic-phase interference device (APHID). The two-ring APHID is shown to be sensitive to rotation

Accounting for the Effect of Noncondensing Gases on Interphasic Heat and Mass Transfer in the Two-Fluid Model Used in the KORSAR Code

Science.gov (United States)

Yudov, Yu. V.

2018-03-01

A model is presented of the interphasic heat and mass transfer in the presence of noncondensable gases for the KORSAR/GP design code. This code was developed by FGUP NITI and the special design bureau OKB Gidropress. It was certified by Rostekhnadzor in 2009 for numerical substantiation of the safety of reactor installations with VVER reactors. The model is based on the assumption that there are three types of interphasic heat and mass transfer of the vapor component: vapor condensation or evaporation on the interphase under any thermodynamic conditions of the phases, pool boiling of the liquid superheated above the saturation temperature at the total pressure, and spontaneous condensation in the volume of gas phase supercooled below the saturation temperature at the vapor partial pressure. Condensation and evaporation on the interphase continuously occur in a two-phase flow and control the time response of the interphase heat and mass transfer. Boiling and spontaneous condensation take place only at the metastable condition of the phases and run at a quite high speed. The procedure used for calculating condensation and evaporation on the interphase accounts for the combined diffusion and thermal resistance of mass transfer in all regimes of the two-phase flow. The proposed approach accounts for, in a natural manner, a decrease in the rate of steam condensation (or generation) in the presence of noncondensing components in the gas phase due to a decrease (or increase) in the interphase temperature relative to the saturation temperature at the vapor partial pressure. The model of the interphase heat transfer also accounts for the processes of dissolution or release of noncondensing components in or from the liquid. The gas concentration at the interphase and on the saturation curve is calculated by the Henry law. The mass transfer coefficient in gas dissolution is based on the heat and mass transfer analogy. Results are presented of the verification of the

Solid‐Phase Synthesis of Structurally Diverse Heterocycles by an Amide–Ketone Condensation/N‐Acyliminium Pictet–Spengler Sequence

DEFF Research Database (Denmark)

Komnatnyy, Vitaly V.; Givskov, Michael Christian; Nielsen, Thomas Eiland

2012-01-01

An efficient approach for the solid‐phase synthesis of structurally diverse heterocyclic compounds is presented. Under acidic reaction conditions, peptidic levulinamides undergo intramolecular ketone–amide condensation reactions to form cyclic N‐acyliminium intermediates. In the presence...

Half-space problem of unsteady evaporation and condensation of polyatomic gas

Science.gov (United States)

Inaba, Masashi; Yano, Takeru

2016-11-01

On the basis of polyatomic version of the ellipsoidal-statistical Bhatnager-Gross-Krook (ES-BGK) model, we consider time-periodic gas flows in a semi-infinite expanse of an initially equilibrium polyatomic gas (methanol) bounded by its planar condensed phase. The kinetic boundary condition at the vapor-liquid interface is assumed to be the complete condensation condition with periodically time-varying macroscopic variables (temperature, saturated vapor density and velocity of the interface), and the boundary condition at infinity is the local equilibrium distribution function. The time scale of variation of macroscopic variables is assumed to be much larger than the mean free time of gas molecules, and the variations of those from a reference state are assumed to be sufficiently small. We numerically investigate thus formulated time-dependent half-space problem for the polyatomic version of linearized ES-BGK model equation with the finite difference method for the case of the Strouhal number Sh=0.01 and 0.1. It is shown that the amplitude of the mass flux at the interface is the maximum, and the phase difference in time between the mass flux and v∞ - vℓ (v∞: vapor velocity at infinity, vℓ: velocity of the vapor-liquid interface) is the minimum absolute value, when the phase difference in time between the liquid surface temperature (the saturated vapor density) and the velocity of interface is close to zero.

Bose-Einstein condensation of photons in a 'white-wall' photon box

International Nuclear Information System (INIS)

Klaers, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin

2011-01-01

Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. Here we report on the realization of a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a 'white-wall' photon box. The cavity mirrors provide a trapping potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by multiple scattering off the dye molecules. Signatures for a BEC upon increased photon density are: a spectral distribution that shows Bose-Einstein distributed photon energies with a macroscopically populated peak on top of a broad thermal wing, the observed threshold of the phase transition showing the predicted absolute value and scaling with resonator geometry, and condensation appearing at the trap centre even for a spatially displaced pump spot.

Bose-Einstein condensation of photons in a 'white-wall' photon box

Science.gov (United States)

Klärs, Jan; Schmitt, Julian; Vewinger, Frank; Weitz, Martin

2011-01-01

Bose-Einstein condensation, the macroscopic ground state occupation of a system of bosonic particles below a critical temperature, has been observed in cold atomic gases and solid-state physics quasiparticles. In contrast, photons do not show this phase transition usually, because in Planck's blackbody radiation the particle number is not conserved and at low temperature the photons disappear in the walls of the system. Here we report on the realization of a photon Bose-Einstein condensate in a dye-filled optical microcavity, which acts as a "white-wall" photon box. The cavity mirrors provide a trapping potential and a non-vanishing effective photon mass, making the system formally equivalent to a two-dimensional gas of trapped massive bosons. Thermalization of the photon gas is reached in a number conserving way by multiple scattering off the dye molecules. Signatures for a BEC upon increased photon density are: a spectral distribution that shows Bose-Einstein distributed photon energies with a macroscopically populated peak on top of a broad thermal wing, the observed threshold of the phase transition showing the predicted absolute value and scaling with resonator geometry, and condensation appearing at the trap centre even for a spatially displaced pump spot.

Dual approaches for defects condensation

Energy Technology Data Exchange (ETDEWEB)

Rougemont, Romulo; Grigorio, Leonardo de Souza; Wotzasek, Clovis [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Guimaraes, Marcelo Santos [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil)

2009-07-01

Full text. Due to the fact that the QCD running coupling constant becomes larger as we go into the low energy (or large distance) limit of the theory, a perturbative treatment of its infrared (IR) region is impossible. In particular, a formal mathematical demonstration of color confinement and a complete physical understanding of the exact mechanism that confines quarks and gluons are two missing points in our current knowledge of the IR-QCD. It was known that due to the Meissner effect of expulsion of magnetic fields in a electric condensate that usual superconductors should confine magnetic monopoles. That point led to the conjecture that the QCD vacuum could be a condensate of chromomagnetic monopoles, a dual superconductor (DSC). Such a chromomagnetic condensate should be responsible for the dual Meissner effect which is expected to lead to the confinement of color charges immersed in this medium. In dual superconductor models of color confinement, magnetic monopoles appear as topological defects in points of the space where the abelian projection becomes singular. Also, condensation of other kinds of defects such as vortices in superfluids and line-like defects in solids are responsible for a great variety of phase transitions, which once more proves the relevance of the subject. In the present work we review two methods that allow us to approach the condensation of defects: the Kleinert Mechanism (KM) and the Julia-Toulouse Mechanism (JTM). We show that in the limit where the vortex gauge field goes to zero, which we identify as the signature of the condensation of defects in the dual picture, these are two equivalent dual prescriptions for obtaining an effective theory for a phase where defects are condensed, starting from the fundamental theory defined in the normal phase where defects are diluted. (author)

Current-phase relation of a Bose-Einstein condensate flowing through a weak link

International Nuclear Information System (INIS)

Piazza, F.; Smerzi, A.; Collins, L. A.

2010-01-01

We study the current-phase relation of a Bose-Einstein condensate flowing through a repulsive square barrier by solving analytically the one-dimensional Gross-Pitaevskii equation. The barrier height and width fix the current-phase relation j(δφ), which tends to j∼cos(δφ/2) for weak barriers and to the Josephson sinusoidal relation j∼sin(δφ) for strong barriers. Between these two limits, the current-phase relation depends on the barrier width. In particular, for wide-enough barriers, we observe two families of multivalued current-phase relations. Diagrams belonging to the first family, already known in the literature, can have two different positive values of the current at the same phase difference. The second family, new to our knowledge, can instead allow for three different positive currents still corresponding to the same phase difference. Finally, we show that the multivalued behavior arises from the competition between hydrodynamic and nonlinear-dispersive components of the flow, the latter due to the presence of a soliton inside the barrier region.

Containment condensing heat transfer

International Nuclear Information System (INIS)

Gido, R.G.; Koestel, A.

1983-01-01

This report presents a mechanistic heat-transfer model that is valid for large scale containment heat sinks. The model development is based on the determination that the condensation is controlled by mass diffusion through the vapor-air boundary layer, and the application of the classic Reynolds' analogy to formulate expressions for the transfer of heat and mass based on hydrodynamic measurements of the momentum transfer. As a result, the analysis depends on the quantification of the shear stress (momentum transfer) at the interface between the condensate film and the vapor-air boundary layer. In addition, the currently used Tagami and Uchida test observations and their range of applicability are explained

Heat and mass transfer in porous media phase separation at temperatures below the lambda-point of He-4

Science.gov (United States)

Yuan, S. W. K.; Frederking, T. H. K.

1986-01-01

Newtonian fluid motion, coupled to heat transfer via latent heat of phase transition, is well known from numerous studies of condensation and boiling. Considerably less knowledge is available for vapor-liquid phase separation in the absence of gravity effect on the transport phenomena. The present studies are focused on heat and mass transfer associated with vapor-liquid phase separation required for long-term storage of the cryogen liquid He II in space vessels. Though space conditions are the dominant mode of interest in advanced equipment, e.g. IR telescopes, the systems may be operated in principle during terrestrial conditions. The latter are considered in the present work. It emphasizes the linear regime including an extrapolation based on variable thermophysical properties. Data taken with a phase separation approach show departures from the linear regime prediction. They agree with a transport equation proposed for the nonlinear, turbulent regime.

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.

SLAC synchronous condenser

International Nuclear Information System (INIS)

Corvin, C.

1995-06-01

A synchronous condenser is a synchronous machine that generates reactive power that leads real power by 90 degrees in phase. The leading reactive power generated by the condenser offsets or cancels the normal lagging reactive power consumed by inductive and nonlinear loads at the accelerator complex. The quality of SLAC's utility power is improved with the addition of the condenser. The inertia of the condenser's 35,000 pound rotor damps and smoothes voltage excursions on two 12 kilovolt master substation buses, improving voltage regulation site wide. The condenser absorbs high frequency transients and noise in effect ''scrubbing'' the electric system power at its primary distribution source. In addition, the condenser produces a substantial savings in power costs. Federal and investor owned utilities that supply electric power to SLAC levy a monthly penalty for lagging reactive power delivered to the site. For the 1993 fiscal year this totaled over $285,000 in added costs for the year. By generating leading reactive power on site, thereby reducing total lagging reactive power requirements, a substantial savings in electric utility bills is achieved. Actual savings of $150,000 or more a year are possible depending on experimental operations

Universal Themes of Bose-Einstein Condensation

Science.gov (United States)

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

Reactive simulation of the chemistry behind the condensed-phase ignition of RDX from hot spots.

Science.gov (United States)

Joshi, Kaushik L; Chaudhuri, Santanu

2015-07-28

Chemical events that lead to thermal initiation and spontaneous ignition of the high-pressure phase of RDX are presented using reactive molecular dynamics simulations. In order to initiate the chemistry behind thermal ignition, approximately 5% of RDX crystal is subjected to a constant temperature thermal pulse for various time durations to create a hot spot. After application of the thermal pulse, the ensuing chemical evolution of the system is monitored using reactive molecular dynamics under adiabatic conditions. Thermal pulses lasting longer than certain time durations lead to the spontaneous ignition of RDX after an incubation period. For cases where the ignition is observed, the incubation period is dominated by intermolecular and intramolecular hydrogen transfer reactions. Contrary to the widely accepted unimolecular models of initiation chemistry, N-N bond dissociations that produce NO2 species are suppressed in the condensed phase. The gradual temperature and pressure increase in the incubation period is accompanied by the accumulation of short-lived, heavier polyradicals. The polyradicals contain intact triazine rings from the RDX molecules. At certain temperatures and pressures, the polyradicals undergo ring-opening reactions, which fuel a series of rapid exothermic chemical reactions leading to a thermal runaway regime with stable gas-products such as N2, H2O and CO2. The evolution of the RDX crystal throughout the thermal initiation, incubation and thermal runaway phases observed in the reactive simulations contains a rich diversity of condensed-phase chemistry of nitramines under high-temperature/pressure conditions.

Spatial energy distribution around energetic ions in condensed phases. Study by thermoluminescence

International Nuclear Information System (INIS)

Montret-Brugerolle, M.

1980-01-01

One describes a model that allows the calculation of the spatial energy distribution around a heavy ion trajectory within the physical step of the phenomena involved (10 -13 s). Experimental data are collected in order to chek the model in the condensed phase. The experimental procedure is thermoluminescence (TL). LiF : Mg, Ti, CaF 2 : Dy and CaF 2 : Mn crystals are irradiated with 60 Co-γ rays and with heavy ions: He, Ne, Cu, Kr of various incident energies. An extensive study of the TL light induced by heavy ions bombardment is carried out as a function of the energy and density of the impinging ions. It is shown that the different response observed with respect to γ-irradiation is due neither to TL traps destruction nor to the recombination of a larger amount of charge-carriers. Experimental data and those obtained from the distribution of energy density are compared, and the agreement is satisfactory. Hence, it is thought that the model may be extended to condensed media [fr

Photothermal experiments on condensed phase samples of agricultural interest : optical and thermal characterization

OpenAIRE

Favier, J.P.

1997-01-01

A rapidly increasing number of photothermal (PT) techniques has had a considerable impact on agriculture and environmental sciences in the last decade. It was the purpose of the work described here to develop and apply new PT techniques in this specific field of research.

Chapter I is a general introduction with an overview of PT techniques used in this research. Two different photoacoustic (PA) techniques used for optical characterization of a variety of condensed phase sa...

Theoretical studying the stability of steady-state regime of a channel with a coolant condensation

International Nuclear Information System (INIS)

Savikhin, O.G.

1987-01-01

Based on the boiling channel stability theory, the channel steady-state stability with the coolant condensation is studied. Condensable coolants are used in the NPP steam-separator superheaters as well as in cryogenic technique. Under certain conditions the coolant flow rate and temperature fluctuations may be excited in the parallel channel system with coolant condensation, which produce a sufficient effect on the heat exchange equipment operation reliability. To describe unsteady processes of heat and mass transfer in the channel, a homogeneous two-phase flow one dimensional model is used. The results obtained allow one to make a conclusion concerning the effect of some parameters on condensing channel steady-state regime stability: reduction of inlet and outlet unheated communication length, pressure drop increase at the outlet plate and its reduction at the inlet one lead to the increase of stability margin

Mechanical ventilation with heated humidifiers: measurements of condensed water mass within the breathing circuit according to ventilatory settings

International Nuclear Information System (INIS)

Schena, E; Saccomandi, P; Cappelli, S; Silvestri, S

2013-01-01

Heated wire humidifiers (HWHs) are widely used to heat and humidify gases during mechanical ventilation. The control strategy implemented on commercial HWHs, based on maintaining constant gas temperature at the chamber outlet, shows weaknesses: humidifying performances depend on environmental temperature and ventilatory settings, and often condensation occurs. Herein, we analyzed in vitro HWH performances focusing on the condensation amount according to ventilatory settings. We used a physical model to define the parameters which mainly influence the HWH performances. In order to investigate the influence of minute volume (MV) and frequency rate (f r ) on condensation, the other influencing parameters were kept constant during experiments, and we introduced a novel approach to estimate the condensation. The method, based on measuring the condensed vapor mass (Δm), provided more objective information than the visual-based scale used in previous studies. Thanks to both the control of other influencing factors and the accurate Δm measures, the investigation showed the Δm increase with MV and f r . Substantial condensation after 7 h of ventilation and the influence of MV and f r on Δm (i.e., Δm = 3 g at MV = 1.5 L min −1 and f r = 8 bpm and Δm = 9.4 g at MV = 8 L min −1 and f r = 20 bpm) confirm the weaknesses of 'single-point temperature' control strategies. (paper)

Molecular equilibrium with condensation

International Nuclear Information System (INIS)

Sharp, C.M.; Huebner, W.F.

1990-01-01

Minimization of the Gibbs energy of formation for species of chemical elements and compounds in their gas and condensed phases determines their relative abundances in a mixture in chemical equilibrium. The procedure is more general and more powerful than previous abundance determinations in multiphase astrophysical mixtures. Some results for astrophysical equations of state are presented, and the effects of condensation on opacity are briefly indicated. 18 refs

Characteristic size and mass of galaxies in the Bose–Einstein condensate dark matter model

Directory of Open Access Journals (Sweden)

Jae-Weon Lee

2016-05-01

Full Text Available We study the characteristic length scale of galactic halos in the Bose–Einstein condensate (or scalar field dark matter model. Considering the evolution of the density perturbation we show that the average background matter density determines the quantum Jeans mass and hence the spatial size of galaxies at a given epoch. In this model the minimum size of galaxies increases while the minimum mass of the galaxies decreases as the universe expands. The observed values of the mass and the size of the dwarf galaxies are successfully reproduced with the dark matter particle mass m≃5×10−22 eV. The minimum size is about 6×10−3m/Hλc and the typical rotation velocity of the dwarf galaxies is O(H/m c, where H is the Hubble parameter and λc is the Compton wave length of the particle. We also suggest that ultra compact dwarf galaxies are the remnants of the dwarf galaxies formed in the early universe.

Phenomenology of renormalons and the OPE from lattice regularization: The gluon condensate and the heavy quark pole mass

Energy Technology Data Exchange (ETDEWEB)

Bali, Gunnar S. [Institut für Theoretische Physik, Universität Regensburg, D-93040 Regensburg (Germany); Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pineda, Antonio [Grup de Física Teòrica and IFAE, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain)

2016-01-22

We study the operator product expansion of the plaquette (gluon condensate) and the self-energy of an infinitely heavy quark. We first compute their perturbative expansions to order α{sup 35} and α{sup 20}, respectively, in the lattice scheme. In both cases we reach the asymptotic regime where the renormalon behavior sets in. Subtracting the perturbative series, we obtain the leading non-perturbative corrections of their respective operator product expansions. In the first case we obtain the gluon condensate and in the second the binding energy of the heavy quark in the infinite mass limit. The results are fully consistent with the expectations from renormalons and the operator product expansion.

HPLC, NMR and MALDI-TOF MS Analysis of Condensed Tannins from Lithocarpus glaber Leaves with Potent Free Radical Scavenging Activity

OpenAIRE

Zhang, Liang Liang; Lin, Yi Ming

2008-01-01

Using acid-catalyzed degradation in the presence of cysteamine, the condensed tannins from Lithocarpus glaber leaves were characterized, following thiolysis, by means of reversed-phase HPLC, 13C-NMR and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analyses. The thiolysis reaction products showed the presence of the procyanidin (PC) and prodelphinidin (PD) structures. The 13C-NMR spectrum revealed that the condensed tannins were comprised of PD (7...

The Impact of Condensed-Phase Viscosity on Multiphase Oxidation Kinetics Involving O3, NO3, and OH

Science.gov (United States)

Li, J.; Forrester, S. M.; Knopf, D. A.

2017-12-01

Organic aerosol (OA) particles are ubiquitous in the atmosphere and have a significant influence on air quality, human health, cloud formation processes and global climate. By now it is well-recognized that organic particulate species can be amorphous in nature, existing in liquid, semi-solid and solid (glassy) phase states. The phase state is modulated by particle composition and environmental conditions such as relative humidity and temperature. These modifications can influence particle viscosity and molecular diffusion and, therefore, impact the reactive uptake of gas-phase oxidants and radicals by the organic substrate. In this study, we determined the reactive uptake coefficients (γ) of O3 by canola oil, NO3 by levoglucosan (LEV) and a LEV/xylitol mixture, and OH by glucose/sulfuric acid mixtures and glucose/1,2,6-hexanetriol mixtures under dry conditions and for temperatures ranging from 293 K to 213 K. Uptake coefficients have been measured employing a chemical ionization mass spectrometer coupled to a temperature-controlled rotating-wall flow reactor. Glass transition temperatures (Tg) of applied substrates were estimated by the Gordon-Taylor equation. Phase states were qualitatively probed via poking experiment using a temperature-controlled cooling stage. Shattering of the substrates indicated the formation of a glassy state. Results show a significant impact of condensed phase state on reactive uptake kinetics whereby γ changed most profoundly around estimated Tg. For example, γ decreases from 6.5×10-4 to 1.9 ×10-5 for O3 uptake by canola oil and from 8.3×10-4 to 3.1×10-4 for NO3 uptake by the LEV/xylitol mixture, respectively. The decrease in γ will be discussed with regard to phase state, desorption lifetime, and Arrhenius temperature dependence of reaction rates. First results of OH uptakes at low temperatures are presented, together with a discussion of the relevant atmospheric implications.

Behavior of the antiferromagnetic phase transition near the fermion condensation quantum phase transition in YbRh{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Shaginyan, V.R., E-mail: vrshag@thd.pnpi.spb.r [Petersburg Nuclear Physics Institute, RAS, Gatchina 188300 (Russian Federation); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Amusia, M.Ya. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Popov, K.G. [Komi Science Center, Ural Division, RAS, Syktyvkar 167982 (Russian Federation)

2010-01-11

Low-temperature specific-heat measurements on YbRh{sub 2}Si{sub 2} at the second order antiferromagnetic (AF) phase transition reveal a sharp peak at T{sub N}=72 mK. The corresponding critical exponent alpha turns out to be alpha=0.38, which differs significantly from that obtained within the framework of the fluctuation theory of second order phase transitions based on the scale invariance, where alphaapprox =0.1. We show that under the application of magnetic field the curve of the second order AF phase transitions passes into a curve of the first order ones at the tricritical point leading to a violation of the critical universality of the fluctuation theory. This change of the phase transition is generated by the fermion condensation quantum phase transition. Near the tricritical point the Landau theory of second order phase transitions is applicable and gives alphaapprox =1/2. We demonstrate that this value of alpha is in good agreement with the specific-heat measurements.

Boilers, evaporators, and condensers

International Nuclear Information System (INIS)

Kakac, S.

1991-01-01

This book reports on the boilers, evaporators and condensers that are used in power plants including nuclear power plants. Topics included are forced convection for single-phase side heat exchangers, heat exchanger fouling, industrial heat exchanger design, fossil-fuel-fired boilers, once through boilers, thermodynamic designs of fossil fuel-first boilers, evaporators and condensers in refrigeration and air conditioning systems (with respect to reducing CFC's) and nuclear steam generators

The Solar Photosphere: Evidence for Condensed Matter

Directory of Open Access Journals (Sweden)

Robitaille P. M.

2006-04-01

Full Text Available The stellar equations of state treat the Sun much like an ideal gas, wherein the photosphere is viewed as a sparse gaseous plasma. The temperatures inferred in the solar interior give some credence to these models, especially since it is counterintuitive that an object with internal temperatures in excess of 1 MK could be existing in the liquid state. Nonetheless, extreme temperatures, by themselves, are insufficient evidence for the states of matter. The presence of magnetic fields and gravity also impact the expected phase. In the end, it is the physical expression of a state that is required in establishing the proper phase of an object. The photosphere does not lend itself easily to treatment as a gaseous plasma. The physical evidence can be more simply reconciled with a solar body and a photosphere in the condensed state. A discussion of each physical feature follows: (1 the thermal spectrum, (2 limb darkening, (3 solar collapse, (4 the solar density, (5 seismic activity, (6 mass displacement, (7 the chromosphere and critical opalescence, (8 shape, (9 surface activity, (10 photospheric/coronal flows, (11 photospheric imaging, (12 the solar dynamo, and (13 the presence of Sun spots. The explanation of these findings by the gaseous models often requires an improbable combination of events, such as found in the stellar opacity problem. In sharp contrast, each can be explained with simplicity by the condensed state. This work is an invitation to reconsider the phase of the Sun.

Proton mixing in -condensed phase of neutron star matter

Energy Technology Data Exchange (ETDEWEB)

Takatsuka, Tatsuyuki

1984-08-01

The mixing of protons in neutron star matter under the occurrence of condensation is studied in the framework of the ALS (Alternating Layer Spin) model and with the effective interaction approach. It is found that protons are likely to mix under the situation and cause a remarkable energy gain from neutron matter as the density increases. The extent of proton mixing becomes larger by about a factor (1.5-2.5) according to the density rho asymptotically equals (2-5)rho0, rho0 being the nuclear density, as compared with that for the case without pion condensation. The reason can be attributed to the two-dimensional nature of the Fermi gas state characteristic of the nucleon system under condensation.

Water interactions with condensed organic phases: a combined experimental and theoretical study of molecular-level processes

Science.gov (United States)

Johansson, Sofia M.; Kong, Xiangrui; Thomson, Erik S.; Papagiannakopoulos, Panos; Pettersson, Jan B. C.; Lovrić, Josip; Toubin, Céline

2016-04-01

Water uptake on aerosol particles modifies their chemistry and microphysics with important implications for air quality and climate. A large fraction of the atmospheric aerosol consists of organic aerosol particles or inorganic particles with condensed organic components. Here, we combine laboratory studies using the environmental molecular beam (EMB) method1 with molecular dynamics (MD) simulations to characterize water interactions with organic surfaces in detail. The over-arching aim is to characterize the mechanisms that govern water uptake, in order to guide the development of physics-based models to be used in atmospheric modelling. The EMB method enables molecular level studies of interactions between gases and volatile surfaces at near ambient pressure,1 and the technique may provide information about collision dynamics, surface and bulk accommodation, desorption and diffusion kinetics. Molecular dynamics simulations provide complementary information about the collision dynamics and initial interactions between gas molecules and the condensed phase. Here, we focus on water interactions with condensed alcohol phases that serve as highly simplified proxies for systems in the environment. Gas-surface collisions are in general found to be highly inelastic and result in efficient surface accommodation of water molecules. As a consequence, surface accommodation of water can be safely assumed to be close to unity under typical ambient conditions. Bulk accommodation is inefficient on solid alcohol and the condensed materials appear to produce hydrophobic surface structures, with limited opportunities for adsorbed water to form hydrogen bonds with surface molecules. Accommodation is significantly more efficient on the dynamic liquid alcohol surfaces. The results for n-butanol (BuOH) are particularly intriguing where substantial changes in water accommodation taking place over a 10 K interval below and above the BuOH melting point.2 The governing mechanisms for the

Investigations on the Steam Condensation in a Vertical Tube Geometry

Energy Technology Data Exchange (ETDEWEB)

Hwang, Ji-Hwan; Jerng, Dong-wook [Chung-Ang University, Seoul (Korea, Republic of)

2016-10-15

In case of accidents that threats containment integrity, such as Station Black Out (SBO), it is able to depressurize containment using exterior-surface condensation in presence of non-condensable gases, which is named as Passive Containment Cooling System (PCCS). It is very important to precisely predict heat removal capability PCCS, as it affects safety and economics. The effect of curvature is not yet experimentally and numerically studied. It is reported that the effect of curvature exists at single-phase condition, yet it is not studied that if it can applicable to two-phase condensation in presence of non-condensables. In this paper, various experimental data are collected to analyze if it is able to observe curvature effect. However, it is hard to analyze experimental data, as the geometry, experimental conditions and means of measurement differs. To check if the differences between experiments are curvature effect, each experiment is compared with CFD simulation result using a commercial CFD code, STAR-CCM+. In this paper, with correlations derived from prior studies, we found the existence of curvature effect under PCCS operating condition. However, it is unable to find out a clear curvature effect at experiment data as they scatter much. As a means of comparison reference between experiment, CFD code is used. From comparison between CFD and experiment, we could confirm the existence of curvature effect. However, measured heat transfer coefficients of Kawakubo’s experiment are relatively low, whereas Dehbi’s measurement data are relatively high. Also, considering that usage of eq. overly supplies steam to condensing shell region, heat transfer coefficients of Pan Tong’s measured relatively high, but not as much that of Dehbi’s. A further experimental identification is needed for evaluation. Currently, CFD code calculates the curvature effect. Overall trend versus air mass fraction is similar with average of experiment.

Spectroscopy of dark soliton states in Bose-Einstein condensates

International Nuclear Information System (INIS)

Bongs, K; Burger, S; Hellweg, D; Kottke, M; Dettmer, S; Rinkleff, T; Cacciapuoti, L; Arlt, J; Sengstock, K; Ertmer, W

2003-01-01

Experimental and numerical studies of the velocity field of dark solitons in Bose-Einstein condensates are presented. The formation process after phase imprinting as well as the propagation of the emerging soliton are investigated using spatially resolved Bragg spectroscopy of soliton states in Bose-Einstein condensates of 87 Rb. A comparison of experimental data to results from numerical simulations of the Gross-Pitaevskii equation clearly identifies the flux underlying a dark soliton propagating in a Bose-Einstein condensate. The results allow further optimization of the phase imprinting method for creating collective excitations of Bose-Einstein condensates

Virtual mass effects in two-phase flow. Topical report

International Nuclear Information System (INIS)

Cheng, L.Y.; Drew, D.A.; Lahey, R.T. Jr.

1978-03-01

The effect of virtual mass on phase separation during the acceleration of a two-phase mixture was studied. Virtual mass can be regarded as an induced inertia on the dispersed phase which is accelerating relative to the continuous phase, and it was found that the virtual mass acceleration is objective, implying an invariance with respect to reference frame. An objective form of the virtual acceleration was derived and required parameters were determined for limiting cases. Analyses determined that experiments on single bubble nozzle/diffuser flow cannot readily discriminate between various virtual mass acceleration models

Numerical modeling of condensation from vapor-gas mixtures for forced down flow inside a tube

International Nuclear Information System (INIS)

Yuann, R.Y.; Schrock, V.E.; Chen, Xiang, M.

1995-01-01

Laminar film condensation is the dominant heat transfer mode inside tubes. In the present paper direct numerical simulation of the detailed transport process within the steam-gas core flow and in the condensate film is carried out. The problem was posed as an axisymmetric two dimensional (r, z) gas phase inside an annular condensate film flow with an assumed smooth interface. The fundamental conservation equations were written for mass, momentum, species concentration and energy in the gaseous phase with effective diffusion parameters characterizing the turbulent region. The low Reynolds number two equation κ-ε model was employed to determine the eddy diffusion coefficients. The liquid film was described by similar formulation without the gas species equation. An empirical correlation was employed to correct for the effect of film waviness on the interfacial shear. A computer code named COAPIT (Condensation Analysis Program Inside Tube) was developed to implement numerical solution of the fundamental equations. The equations were solved by a marching technique working downstream from the entrance of the condensing section. COAPIT was benchmarked against experimental data and overall reasonable agreement was found for the key parameters such as heat transfer coefficient and tube inner wall temperature. The predicted axial development of radial profiles of velocity, composition and temperature and occurrence of metastable vapor add insight to the physical phenomena

Numerical modeling of condensation from vapor-gas mixtures for forced down flow inside a tube

Energy Technology Data Exchange (ETDEWEB)

Yuann, R Y [Taiwan Power Company, Taipei (Taiwan, Province of China); Schrock, V E [Univ. of California, Berkeley, CA (United States); Chen, Xiang

1995-09-01

Laminar film condensation is the dominant heat transfer mode inside tubes. In the present paper direct numerical simulation of the detailed transport process within the steam-gas core flow and in the condensate film is carried out. The problem was posed as an axisymmetric two dimensional (r, z) gas phase inside an annular condensate film flow with an assumed smooth interface. The fundamental conservation equations were written for mass, momentum, species concentration and energy in the gaseous phase with effective diffusion parameters characterizing the turbulent region. The low Reynolds number two equation {kappa}-{epsilon} model was employed to determine the eddy diffusion coefficients. The liquid film was described by similar formulation without the gas species equation. An empirical correlation was employed to correct for the effect of film waviness on the interfacial shear. A computer code named COAPIT (Condensation Analysis Program Inside Tube) was developed to implement numerical solution of the fundamental equations. The equations were solved by a marching technique working downstream from the entrance of the condensing section. COAPIT was benchmarked against experimental data and overall reasonable agreement was found for the key parameters such as heat transfer coefficient and tube inner wall temperature. The predicted axial development of radial profiles of velocity, composition and temperature and occurrence of metastable vapor add insight to the physical phenomena.

Phase-locking in quantum and classical oscillators: polariton condensates, lasers, and arrays of Josephson junctions

OpenAIRE

EASTHAM, PAUL

2003-01-01

PUBLISHED We connect three phenomena in which a coherent electromagnetic field could be generated: polariton condensation, phase-locking in arrays of underdamped Josephson junctions, and lasing. All these phenomena have been described using Dicke-type models of spins coupled to a single photon mode. These descriptions may be distinguished by whether the spins are quantum or classical, and whether they are strongly or weakly damped.

Investigating tunable KRb gases and Bose-Einstein condensates

DEFF Research Database (Denmark)

Jørgensen, Nils Byg

2015-01-01

We present the production of dual-species Bose-Einstein condensates of 39K and 87Rb with tunable interactions. A dark spontaneous force optical trap was used for 87Rb to reduce the losses in 39K originating from light-assisted collisions in the magneto optical trapping phase. Using sympathetic...... for dual-species condensates with tunable interactions. Employing the dual-species condensates, the miscible to immiscible phase transition was investigated. By applying an empirical model, the transition was used to determine the background scattering length. Two species quantum gases with tunable...

Models of coherent exciton condensation

International Nuclear Information System (INIS)

Littlewood, P B; Eastham, P R; Keeling, J M J; Marchetti, F M; Simons, B D; Szymanska, M H

2004-01-01

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers

Models of coherent exciton condensation

Energy Technology Data Exchange (ETDEWEB)

Littlewood, P B [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Eastham, P R [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Keeling, J M J [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Marchetti, F M [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Simons, B D [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom); Szymanska, M H [Theory of Condensed Matter, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)

2004-09-08

That excitons in solids might condense into a phase-coherent ground state was proposed about 40 years ago, and has been attracting experimental and theoretical attention ever since. Although experimental confirmation has been hard to come by, the concepts released by this phenomenon have been widely influential. This tutorial review discusses general aspects of the theory of exciton and polariton condensates, focusing on the reasons for coherence in the ground state wavefunction, the BCS to Bose crossover(s) for excitons and for polaritons, and the relationship of the coherent condensates to standard lasers.

3-dimensional lattice studies of the electroweak phase transition at MHiggs∼ 70 GeV

International Nuclear Information System (INIS)

Guertler, M.; Perlt, H.; Schiller, A.; Ilgenfritz, E.M.; Kripfganz, J.

1996-06-01

We study the electroweak phase transition by lattice simulations of an effective 3-dimensional theory, for a Higgs mass of about 70 GeV. Exploiting, among others, a variant of the equal weight criterion of phase equilibrium, we obtain transition temperature, latent heat and surface tension, and compare with M H ∼35 GeV. In the broken phase masses and Higgs condensates are compared to perturbation theory. For the symmetric phase, bound state masses and the static force are determined. (orig.)

Investigation of the condensing vapor bubble behavior through CFD simulation

International Nuclear Information System (INIS)

Sablania, Sidharth; Verma, Akash; Goyal, P.; Dutta, Anu; Singh, R.K.

2013-09-01

In nuclear systems the sub-cooled boiling flow is an important problem due to the behavior of condensing vapor bubble which has a large effect on the heat transfer characteristics as well as pressure drops and flow instability. The sub-cooled boiling flows become very complex and dynamic phenomena by the vapor bubble-water interaction. This happens due to the boiling/condensation, break-up, and coalescence of the bubble and needs to be addressed for characterizing the above mentioned flow parameters. There have been many researches to analyze the behavior of bubble experimentally and analytically. However, it is very difficult to get complete information about the behavior of bubble because of ever changing interface between vapor and water phase due to bubble condensation/evaporation Therefore, it is necessary to carry out a CFD simulation for better understanding the complex phenomenon of the bubble behavior. The present work focuses on the simulation of condensing bubble in subcooled boiling flow using (Volume of Fluid) VOF method in the CFD code CFD-ACE+. In order to simulate the heat and mass transfer through the bubble interface, CFD modeling for the bubble condensation was developed by modeling the source terms in the governing equations of VOF model using the User-Defined Function (UDF) in CFD-ACE+ code. The effect of condensation on bubble behavior was analyzed by comparing the behavior of condensing bubble with that of adiabatic bubble. It was observed that the behavior of condensing bubble was different from that of non condensing bubble in respect of bubble shape, diameter, velocity etc. The results obtained from the present simulation in terms of various parameters such as bubble velocity, interfacial area and bubble volume agreed well with the reported experimental results verified with FLUENT code in available literature. Hence, this CFD-ACE+ simulation of single bubble condensation will be a useful computational fluid dynamics tool for analyzing the

Wetting and Capillary Condensation as Means of Protein Organization in Membranes

DEFF Research Database (Denmark)

Gil, Tamir; Sabra, Mads Christian; Ipsen, John Hjorth

1997-01-01

Wetting and capillary condensation are thermodynamic phenomena in which the special affinity of interfaces to a thermodynamic phase, relative to the stable bulk phase, leads to the stabilization of a wetting phase at the interfaces. Wetting and capillary condensation are here proposed as mechanisms...

Novel Quantum Condensates in Excitonic Matter

International Nuclear Information System (INIS)

Littlewood, P. B.; Keeling, J. M. J.; Simons, B. D.; Eastham, P. R.; Marchetti, F. M.; Szymanska, M. H.

2009-01-01

These lectures interleave discussion of a novel physical problem of a new kind of condensate with teaching of the fundamental theoretical tools of quantum condensed matter field theory. Polaritons and excitons are light mass composite bosons that can be made inside solids in a number of different ways. As bosonic particles, they are liable to make a phase coherent ground state - generically called a Bose-Einstein condensate (BEC) - and these lectures present some models to describe that problem, as well as general approaches to the theory. The focus is very much to explain how mean-field-like approximations that are often presented heuristically can be derived in a systematic fashion by path integral methods. Going beyond the mean field theory then produces a systematic approach to calculation of the excitation energies, and the derivation of effective low energy theories that can be generalised to more complex dynamical and spatial situations than is practicable for the full theory, as well as to study statistical properties beyond the semi-classical regime. in particular, for the polariton problem, it allows one to connect the regimes of equilibrium BEC and non-equilibrium laser. The lectures are self-sufficient, but not highly detailed. The methodological aspects are covered in standard quantum field theory texts and the presentation here is deliberately cursory: the approach will be closest to the book of Altland and Simons. Since these lectures concern a particular type of condensate, reference should also be made to texts on BEC, for example by Pitaevskii and Stringari. A recent theoretically focussed review of polariton systems covers many of the technical issues associated with the polariton problem in greater depth and provides many further references.

Condensation in gas transmission pipelines. Phase behavior of mixtures of hydrogen with natural gas

Energy Technology Data Exchange (ETDEWEB)

Schouten, J.A.; Michels, J.P.J. [Amsterdam Univ. (Netherlands). Van der Waals-Zeeman Inst.; Rosmalen, R.J. van [Energy, Roden (Netherlands)

2005-05-01

Several pressure and temperature reductions occur along gas transmission lines. Since the pressure and temperature conditions of the natural gas in the pipeline are often close to the dew point curve, liquid dropout can occur. Injection of hydrogen into the natural gas will change the phase envelope and thus the liquid dropout. This condensation of the heavy hydrocarbons requires continuous operational attention and a positive effect of hydrogen may affect the decision to introduce hydrogen. In this paper we report on calculations of the amount of condensate in a natural gas and in this natural gas mixed with 16.7% hydrogen. These calculations have been performed at conditions prevailing in gas transport lines. The results will be used to discuss the difference in liquid dropout in a natural gas and in a mixture with hydrogen at pressure reduction stations, at crossings under waterways, at side-branching, and at separators in the pipelines. (author)

Stepwise Bose-Einstein Condensation in a Spinor Gas.

Science.gov (United States)

Frapolli, C; Zibold, T; Invernizzi, A; Jiménez-García, K; Dalibard, J; Gerbier, F

2017-08-04

We observe multistep condensation of sodium atoms with spin F=1, where the different Zeeman components m_{F}=0,±1 condense sequentially as the temperature decreases. The precise sequence changes drastically depending on the magnetization m_{z} and on the quadratic Zeeman energy q (QZE) in an applied magnetic field. For large QZE, the overall structure of the phase diagram is the same as for an ideal spin-1 gas, although the precise locations of the phase boundaries are significantly shifted by interactions. For small QZE, antiferromagnetic interactions qualitatively change the phase diagram with respect to the ideal case, leading, for instance, to condensation in m_{F}=±1, a phenomenon that cannot occur for an ideal gas with q>0.

Bose-Einstein condensation of excitons in Cu2O

International Nuclear Information System (INIS)

Snoke, D.W.

1990-01-01

Free excitons provide the only experimental system other than helium in which the behavior of particles with mass is known to follow Bose-Einstein statistics. Experimental observations are presented of the kinetic energy distribution of excitons in the direct-gap semiconductor Cu 2 O, both the triplet orthoexciton state and the singlet paraexciton state. The density and temperature of the exciton gas closely follow the phase boundary for Bose-Einstein condensation. At the highest densities, the lower-lying paraexcitons take on an anomalous energy distribution with a sharp, high-energy edge. This odd distribution of particle energies may be associated with Bose-Einstein condensation into a state with nonzero momentum. Indeed, the excitons leave the region of their creation at supersonic velocities. In addition to the experimental observations, theoretical models are presented for several aspects of this nonequilibrium system. The equilibration of a nearly-ideal boson gas is modeled, finding that a significant time is required for the approach to condensation. The temperature and density of the excitons in steady state are modeled based on known classical kinetic effects in semiconductors, and the effects of Bose-Einstein statistics on these processes estimated

Bosonization with inclusion of the gluon condensate

International Nuclear Information System (INIS)

Ebert, D.; Volkov, M.K.

1994-01-01

The effects of the gluon condensate on the quark condensate and on masses and coupling constants of composite mesons are discussed within a QCD-motivated Nambu-Jona-Lasinio model for zero temperature as well as for the case of finite temperature and baryon number density. (orig.)

The physics of exciton-polariton condensates

CERN Document Server

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...

Titanium application to power plant condensers

International Nuclear Information System (INIS)

Itoh, H.

1987-01-01

Recently, the growth of operating performance and construction plan of titanium-tubed condensers in thermal and unclear power plants has been very impressive. High-quality, thinner welded titanium tubes used for cooling tubes, matching design specifications of condensers, have been stably supplied through mass production. It now can be said that various technical problems for titanium-tubed condensers have been solved, but data on operating performance in large-scale commercial plants are still scarce, and site-by-site information needs be exchanged more frequently and on a larger scale. Projects to replace existing condenser cooling tubes with those of corrosion-resistant titanium have been actively furthered, with the only remaining barrier to full employment being cost effectiveness. It is hoped that condenser and tube manufacturers will conduct more joint value analyses

Condensation with two constraints and disorder

Science.gov (United States)

Barré, J.; Mangeolle, L.

2018-04-01

We consider a set of positive random variables obeying two additive constraints, a linear and a quadratic one; these constraints mimic the conservation laws of a dynamical system. In the simplest setting, without disorder, it is known that such a system may undergo a ‘condensation’ transition, whereby one random variable becomes much larger than the others; this transition has been related to the spontaneous appearance of non linear localized excitations in certain nonlinear chains, called breathers. Motivated by the study of breathers in a disordered discrete nonlinear Schrödinger equation, we study different instances of this problem in presence of a quenched disorder. Unless the disorder is too strong, the phase diagram looks like the one without disorder, with a transition separating a fluid phase, where all variables have the same order of magnitude, and a condensed phase, where one variable is much larger than the others. We then show that the condensed phase exhibits various degrees of ‘intermediate symmetry breaking’: the site hosting the condensate is chosen neither uniformly at random, nor is it fixed by the disorder realization. Throughout the article, our heuristic arguments are complemented with direct Monte Carlo simulations.

Where do winds come from? A new theory on how water vapor condensation influences atmospheric pressure and dynamics

Science.gov (United States)

Makarieva, A. M.; Gorshkov, V. G.; Sheil, D.; Nobre, A. D.; Li, B.-L.

2013-01-01

Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power - this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

Models for assessing the relative phase velocity in a two-phase flow. Status report

International Nuclear Information System (INIS)

Schaffrath, A.; Ringel, H.

2000-06-01

The knowledge of slip or drift flux in two phase flow is necessary for several technical processes (e.g. two phase pressure losses, heat and mass transfer in steam generators and condensers, dwell period in chemical reactors, moderation effectiveness of two phase coolant in BWR). In the following the most important models for two phase flow with different phase velocities (e.g. slip or drift models, analogy between pressure loss and steam quality, ε - ε models and models for the calculation of void distribution in reposing fluids) are classified, described and worked up for a further comparison with own experimental data. (orig.)

Condensation heat transfer of a feed-water heater and improvement of its performance

International Nuclear Information System (INIS)

Takamori, Kazuhide; Murase, Michio; Baba, Yoshikazu; Aihara, Tsuyoshi

1995-01-01

In this study, a condensation heat transfer model, coupled with a three-dimensional two-phase flow analysis, was developed. In the heat transfer model, the liquid film flow rate on the heat transfer tubes was calculated by a mass balance equation and the liquid film thickness was calculated from the liquid film flow rate using Nusselt's laminar flow model and Fujii's equation for the steam velocity effect. The model was verified by condensation heat transfer experiments. In the experiments, 112 horizontal, staggered tubes with an outer diameter of 16mm and length of 0.55m were used. The calculated over-all heat transfer coefficients agreed with the data within ±5% under the inlet quality conditions of 13-100%. Based on a three-dimensional two-phase flow analysis, an improved feed-water heater with support plates, which have flow holes between the upper and lower tube bundles, was designed. The total heat exchange capacity of the improved feed-water heater increased about 6%. (author)

Heat transfer during condensation of HFC-134a and R-404A inside of a horizontal smooth and micro-fin tube

Energy Technology Data Exchange (ETDEWEB)

Sapali, S N [Govt. College of Engineering, Department of Mechanical Engineering, Shivaji Nagar, Pune, Maharashtra 411 005 (India); Patil, Pradeep A [AISSMS College of Engineering, Pune University, Mechanical Engineering Department, Kennedy Road, Near R.T.O., Pune, Maharashtra 411 001 (India)

2010-11-15

In recent small and medium capacity refrigeration systems, the condenser tubes are provided with micro-fins from inside. The vapour refrigerant at the compressor outlet and the condenser inlet is in superheat state. As it advances in the condenser it is in two phases and at the outlet it is in sub cooled liquid. The heat transfer coefficient (HTC) during condensation of HFC-134a and R-404A in a smooth (8.56 mm ID) and micro-fin tubes (8.96 mm ID) are experimentally investigated. Different from previous studies, the present experiments are performed for various condensing temperatures, with superheating and sub cooling and using hermetically sealed compressor. The test runs are done at average saturated condensing temperatures ranging from 35 C to 60 C. The mass fluxes are between 90 and 800 kg m{sup -2} s{sup -1}. The experimental results indicate that the average HTC increases with mass flux but decreases with increasing condensing temperature for both smooth and micro-fin tubes. The average condensation HTCs of HFC-134a and R-404A for the micro-fin tubes were 1.5-2.5 and 1.3-2 times larger than that in smooth tube respectively. The HTCs for R-404A are less than that of HFC-134a. New correlations based on the data gathered during the experimentation for predicting condensation HTCs are proposed for wide range of operating conditions. (author)

Experimental investigation of condensation and mixing during venting of a steam / non-condensable gas mixture into a pressure suppression pool

Energy Technology Data Exchange (ETDEWEB)

De Walsche, C.; Cachard, F. de

2000-07-01

Experiments have been performed in the LINX facility to investigate condensation and mixing phenomena in pressure Suppression Pools (SPs), in the context of the European Simplified Boiling Water Reactor (ESBWR) study. As a contribution to the TEPSS project of the 4th European Framework Programme, eight medium-scale, separate-effect tests were carried out in which constant steam/air flow rates were injected below the surface of a two-metre diameter water pool, maintained at constant pressure, through a large downward vent. The vessel pressure was regulated, the pool temperature rising until equilibrium conditions with the incoming gas were reached. The SP temperature distribution was measured, as well as the inlet and outlet gas flow rates, and the overall condensation rate was estimated using mass and heat balances. The test matrix was based on steam mass floret and air mass fraction of the injected gas, the vent immersion depth, and the vessel pressure. Overall, the condensation was shown to be efficient for all tests performed, even for high non-condensable gas concentrations of the injected gas. Thermal stratification above the vent outlet was shown to be moderate. The tests performed allowed a better understanding to be gained of the mechanisms of condensation and mixing in the SP and Wetwell, and results were incorporated into an ORACLE database, to be used for further model development. (authors)

Effect of design and operation parameters on heat transfer coefficient in condensers

International Nuclear Information System (INIS)

Eskin, N.; Arslan, G.; Balci, T.

2009-01-01

Accurate and optimum usage of energy sources is gaining importance all over the world due to the increase of energy need and limited energy sources. Increasing condenser efficiency, reduce both the dimensions and the material usage and also the investment cost of the devices. This can be maintained by increasing the heat transfer coefficient in condensers. Generally, tubes having plain inner surfaces are mounted horizontally in serpentine type condenser applications and due to the performance loss results from the congestion in serpentine connections, vertical tube mounting is not preferred. Due to the complexity of the two-phase flow, a single set of correlation for heat transfer cannot be used. Average and local heat transfer coefficient for condensers are determined. Moreover, for each experiments flow pattern is determined and the validity of the correlations are compared according to that flow pattern. In Table 2, some of the experiments for R134a are listed. Local heat transfer coefficient is also important for condenser design. As a result, to design effective condensers the accuracy of the correlations is very important. When all the experiments are taken into account, it is seen that deviation of the correlations differs according to the refrigerant type, tube dimensions, mass flux, saturation temperature and flow pattern. For high mass flux (>400 kg/m 2 s) Traviss (1973) correlation failed. For small diameters (<3.14 mm) Tandon (1985) correlation estimate the heat transfer coefficient with a high deviation. Most accurate results are obtained for Akers et al. (1959), M.M. Shah (1978), Cavallini and Zecchlin (1974), J.R. Thome - J. El Hajal - A. Cavallini (2003) correlations. For high mass flux and annular flow, M.M. Shah (1978) correlation estimates the heat transfer coefficient with high precision. However, as the tube diameter decrease, this deviation increases. For small tube diameter such as 0.691 mm Cavallini and Zecchlin (1974) gives the most

QCD under extreme conditions. Inhomogeneous condensation

Energy Technology Data Exchange (ETDEWEB)

Heinz, Achim

2014-10-15

Almost 40 years after the first publication on the phase diagram of quantum chromodynamics (QCD) big progress has been made but many questions are still open. This work covers several aspects of low-energy QCD and introduces advanced methods to calculate selected parts of the QCD phase diagram. Spontaneous chiral symmetry breaking as well as its restoration is a major aspect of QCD. Two effective models, the Nambu-Jona-Lasinio (NJL) model and the linear σ-model, are widely used to describe the QCD chiral phase transition. We study the large-N{sub c} behavior of the critical temperature T{sub c} for chiral symmetry restoration in the framework of both models. While in the NJL model T{sub c} is independent of N{sub c} (and in agreement with the expected QCD scaling), the scaling behavior in the linear σ-model reads T{sub c} ∝ N{sup 1/2}{sub c}. However, this mismatch can be corrected: phenomenologically motivated temperature-dependent parameters or the extension with the Polyakov-loop renders the scaling in the linear σ-model compatible with the QCD scaling. The requirement that the chiral condensate which is the order parameter of the chiral symmetry is constant in space is too restrictive. Recent studies on inhomogeneous chiral condensation in cold, dense quark matter suggest a rich crystalline structure. These studies feature models with quark degrees of freedom. In this thesis we investigate the formation of the chiral density wave (CDW) in the framework of the so-called extended linear sigma model (eLSM) at high densities and zero temperature. The eLSM is a modern development of the linear σ-model which contains scalar, pseudoscalar, vector, as well as axial-vector mesons, and in addition, a light tetraquark state. The nucleon and its chiral partner are introduced as parity doublets in the mirror assignment. The model describes successfully the vacuum phenomenology and nuclear matter ground-state properties. As a result we find that an inhomogeneous phase

Condensation of exciton polaritons

International Nuclear Information System (INIS)

Kasprzak, J.

2006-10-01

Because of their unique property of bringing pure quantum effects into the real world scale, phase transitions towards condensed phases - like Bose-Einstein condensation (BEC), superfluidity, and superconductivity - have always fascinated scientists. The BEC, appearing upon cooling a gas of bosons below a critical temperature, has been given a striking demonstration in dilute atomic gases of rubidium atoms at temperatures below 200 nK. By confining photons in a semiconductor micro-cavity, and strongly coupling them to electronic excitations, one may create polaritons. These bosonic quasi-particles are 10 9 times lighter than rubidium atoms, thus theoretically allowing a BEC at standard cryogenic temperatures. Here we detail a comprehensive set of experiments giving compelling evidence for a BEC of polaritons. Above a critical density, we observe massive occupation of the ground state, developing from a thermalized and saturated distribution of the polariton population at (16-20) K. We demonstrate as well the existence of a critical temperature for this transition. The spontaneous onset of a coherent state is manifested by the increase of temporal coherence, the build-up of long-range spatial coherence and the reduction of the thermal noise observed in second order coherence experiments. The marked linear polarization of the emission from the condensate is also measured. All of these findings indicate the spontaneous onset of a macroscopic quantum phase. (author)

Characteristics of Vacuum Freeze Drying with Utilization of Internal Cooling and Condenser Waste Heat for Sublimation

Directory of Open Access Journals (Sweden)

Muhammad Alhamid

2013-09-01

Full Text Available Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing by internal cooling prevents evaporation until the mass of the specimen is 0.47 g and promotes transition of the specimen into the solid phase.

Interstellar silicate analogs for grain-surface reaction experiments: Gas-phase condensation and characterization of the silicate dust grains

Energy Technology Data Exchange (ETDEWEB)

Sabri, T.; Jäger, C. [Laboratory Astrophysics Group of the Max Planck Institute for Astronomy at the Friedrich Schiller University Jena Institute of Solid State Physics, Helmholtzweg 3, D-07743 Jena (Germany); Gavilan, L.; Lemaire, J. L.; Vidali, G. [Observatoire de Paris/Université de Cergy-Pontoise, 5 mail Gay Lussac, F-95000 Cergy-Pontoise (France); Mutschke, H. [Laboratory Astrophysics Group of the Astrophysical Institute and University Observatory, Friedrich Schiller University Jena Schillergässchen 3, D-07743 Jena (Germany); Henning, T., E-mail: tolou.sabri@uni-jena.de [Max Planck Institute for Astronomy Königstuhl 17, D-69117 Heidelberg (Germany)

2014-01-10

Amorphous, astrophysically relevant silicates were prepared by laser ablation of siliceous targets and subsequent quenching of the evaporated atoms and clusters in a helium/oxygen gas atmosphere. The described gas-phase condensation method can be used to synthesize homogeneous and astrophysically relevant silicates with different compositions ranging from nonstoichiometric magnesium iron silicates to pyroxene- and olivine-type stoichiometry. Analytical tools have been used to characterize the morphology, composition, and spectral properties of the condensates. The nanometer-sized silicate condensates represent a new family of cosmic dust analogs that can generally be used for laboratory studies of cosmic processes related to condensation, processing, and destruction of cosmic dust in different astrophysical environments. The well-characterized silicates comprising amorphous Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4}, as well as the corresponding crystalline silicates forsterite and fayalite, produced by thermal annealing of the amorphous condensates, have been used as real grain surfaces for H{sub 2} formation experiments. A specifically developed ultra-high vacuum apparatus has been used for the investigation of molecule formation experiments. The results of these molecular formation experiments on differently structured Mg{sub 2}SiO{sub 4} and Fe{sub 2}SiO{sub 4} described in this paper will be the topic of the next paper of this series.

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D.; Schilling, Katherine A.; Loza, Christine L.; Craven, Jill S.; Zuend, Andreas; Ziemann, Paul J.; Seinfeld, John H.

2013-01-01

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process. PMID:23818634

Size distribution dynamics reveal particle-phase chemistry in organic aerosol formation.

Science.gov (United States)

Shiraiwa, Manabu; Yee, Lindsay D; Schilling, Katherine A; Loza, Christine L; Craven, Jill S; Zuend, Andreas; Ziemann, Paul J; Seinfeld, John H

2013-07-16

Organic aerosols are ubiquitous in the atmosphere and play a central role in climate, air quality, and public health. The aerosol size distribution is key in determining its optical properties and cloud condensation nucleus activity. The dominant portion of organic aerosol is formed through gas-phase oxidation of volatile organic compounds, so-called secondary organic aerosols (SOAs). Typical experimental measurements of SOA formation include total SOA mass and atomic oxygen-to-carbon ratio. These measurements, alone, are generally insufficient to reveal the extent to which condensed-phase reactions occur in conjunction with the multigeneration gas-phase photooxidation. Combining laboratory chamber experiments and kinetic gas-particle modeling for the dodecane SOA system, here we show that the presence of particle-phase chemistry is reflected in the evolution of the SOA size distribution as well as its mass concentration. Particle-phase reactions are predicted to occur mainly at the particle surface, and the reaction products contribute more than half of the SOA mass. Chamber photooxidation with a midexperiment aldehyde injection confirms that heterogeneous reaction of aldehydes with organic hydroperoxides forming peroxyhemiacetals can lead to a large increase in SOA mass. Although experiments need to be conducted with other SOA precursor hydrocarbons, current results demonstrate coupling between particle-phase chemistry and size distribution dynamics in the formation of SOAs, thereby opening up an avenue for analysis of the SOA formation process.

Condensation of bosons with Rashba-Dresselhaus spin-orbit coupling

International Nuclear Information System (INIS)

Baym, Gordon; Ozawa, Tomoki

2014-01-01

Cold atomic Bose-Einstein systems in the presence of simulated Rashba- Dresselhaus spin-orbit coupling exhibit novel physical features. With pure in-plane Rashba coupling the system is predicted in Bogoliubov-Hartree-Fock to have a stable Bose condensate below a critical temperature, even though the effective density of states is two-dimensional. In addition the system has a normal state at all temperatures. We review here the new physics when the system has such spin-orbit coupling, and discuss the nature of the finite temperature condensation phase transition from the normal to condensed phases.

Neutron stars with kaon condensation in relativistic effective model

International Nuclear Information System (INIS)

Wu, Chen; Ma, Yugang; Qian, Weiliang; Yang, Jifeng

2013-01-01

Relativistic mean-field theory with parameter sets FSUGold and IU-FSU is extended to study the properties of neutron star matter in β equilibrium by including Kaon condensation. The mixed phase of normal baryons and Kaon condensation cannot exist in neutron star matter for the FSUGold model and the IU-FSU model. In addition, it is found that when the optical potential of the K - in normal nuclear matter U K ≳ -100 MeV, the Kaon condensation phase is absent in the inner cores of the neutron stars. (author)

Diffusion layer modeling for condensation with multi-component noncondensable gases

International Nuclear Information System (INIS)

Peterson, P.F.

1999-01-01

Many condensation problems involving noncondensable gases have multiple noncondensable species, for example air (with nitrogen, oxygen, and other gases); and other problems where light gases like hydrogen may mix with heavier gases like nitrogen. Particularly when the binary mass diffusion coefficients of the noncondensable species are substantially different, the noncondensable species tend to segregate in the condensation boundary layer. This paper presents a fundamental analysis of the mass transport with multiple noncondensable species, identifying a simple method to calculate an effective mass diffusion coefficient that can be used with the simple diffusion layer model, and discusses in detail the effects of using mass and mole based quantities, and various simplifying approximations, on predicted condensation rates. The results are illustrated with quantitative examples to demonstrate the potential importance of multi-component noncondensable gas effects

Contact condensation effects in the main coolant pipe

International Nuclear Information System (INIS)

Haefner, W.; Fischer, K.

1990-01-01

Contact condensation effects may occur in a pressurized water reactor (PWR) after a loss of coolant accident (LOCA) when emergency core cooling (ECC) water is injected contact with escaping steam which is generated within the core. The condensation which takes place may cause a sudden depressurization leading to the formation of water slugs. The interaction between the transient condensation and the inertia of the flow may also result in large amplitude flow and pressure oscillations. These contact condensation effects are of great importance for the mass flow distribution and the coolant water supply to the reactor core. To examine those complex processes, large computer codes are necessary. The development and verification of analytical models requires greatly simplified flow boundary conditions from experiments and a sufficiently large base of experimental data. Separate models have been developed for interfacial exchange of mass, momentum and energy with respect to the associated flow regime. Therefore, an adequate description of the condensation process requires the modeling of two different topics: the prediction of the flow regime and the calculation of the interfacial exchange. (author)

The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

KAUST Repository

Alshaarawi, Amjad; Bisetti, Fabrizio

2015-01-01

A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

KAUST Repository

Alshaarawi, Amjad

2015-03-01

A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

Scattering of atoms on a Bose-Einstein condensate

International Nuclear Information System (INIS)

Poulsen, Uffe V.; Moelmer, Klaus

2003-01-01

We study the scattering properties of a Bose-Einstein condensate held in a finite depth well when the incoming particles are identical to the ones in the condensate. We calculate phase shifts and corresponding transmission and reflection coefficients, and we show that the transmission times can be negative, i.e., the atomic wave packet seemingly leaves the condensate before it arrives

Numerical Analysis of Integral Characteristics for the Condenser Setups of Independent Power-Supply Sources with the Closed-Looped Thermodynamic Cycle

Directory of Open Access Journals (Sweden)

Vysokomorny Vladimir S.

2016-01-01

Full Text Available The mathematical model of heat and mass transfer processes with phase transition is developed. It allows analyzing of integral characteristics for the condenser setup of independent power-supply plant with the organic Rankine cycle. Different kinds of organic liquids can be used as a coolant and working substance. The temperatures of the working liquid at the condenser outlet under different values of outside air temperature are determined. The comparative analysis of the utilization efficiency of different cooling systems and organic coolants is carried out.

Numerical Analysis of Integral Characteristics for the Condenser Setups of Independent Power-Supply Sources with the Closed-Looped Thermodynamic Cycle

Directory of Open Access Journals (Sweden)

Olga V. Vysokomornaya

2015-01-01

Full Text Available The mathematical model of heat and mass transfer processes with phase transition is developed. It allows analysis of integral characteristics for the condenser setup of independent power-supply plant with the organic Rankine cycle. Different kinds of organic liquids can be used as a coolant and working substance. The temperatures of the working liquid at the condenser outlet under different values of outside air temperature are determined. The comparative analysis of the utilization efficiency of different cooling systems and organic coolants is carried out.

Angular distribution and atomic effects in condensed phase photoelectron spectroscopy

International Nuclear Information System (INIS)

Davis, R.F.

1981-11-01

A general concept of condensed phase photoelectron spectroscopy is that angular distribution and atomic effects in the photoemission intensity are determined by different mechanisms, the former being determined largely by ordering phenomena such as crystal momentum conservation and photoelectron diffraction while the latter are manifested in the total (angle-integrated) cross section. In this work, the physics of the photoemission process is investigated in several very different experiments to elucidate the mechanisms of, and correlation between, atomic and angular distribution effects. Theoretical models are discussed and the connection betweeen the two effects is clearly established. The remainder of this thesis, which describes experiments utilizing both angle-resolved and angle-integrated photoemission in conjunction with synchrotron radiation in the energy range 6 eV less than or equal to h ν less than or equal to 360 eV and laboratory sources, is divided into three parts

Computational simulations of direct contact condensation as the driving force for water hammer

International Nuclear Information System (INIS)

Ceuca, Sabin-Cristian

2015-01-01

An analysis, based on Computer Simulations of the Direct Contact Condensation as the Driving Force for the Condensation Induced Water Hammer phenomenon is performed within this thesis. The goal of the work is to develop a mechanistic HTC model, with predictive capabilities for the simulation of horizontal or nearly horizontal two-phase ows with complex patterns including the e ect of interfacial heat and mass transfer. The newly developed HTC model was implemented into the system code ATHLET and into the CFD tools ANSYS CFX and OpenFOAM. Validation calculations have been performed for horizontal or nearly horizontal ows, where simulation results have been compared against the local measurement data such as void and temperature or area averaged data delivered by a wire mesh sensor.

Computational simulations of direct contact condensation as the driving force for water hammer

Energy Technology Data Exchange (ETDEWEB)

Ceuca, Sabin-Cristian

2015-04-27

An analysis, based on Computer Simulations of the Direct Contact Condensation as the Driving Force for the Condensation Induced Water Hammer phenomenon is performed within this thesis. The goal of the work is to develop a mechanistic HTC model, with predictive capabilities for the simulation of horizontal or nearly horizontal two-phase ows with complex patterns including the e ect of interfacial heat and mass transfer. The newly developed HTC model was implemented into the system code ATHLET and into the CFD tools ANSYS CFX and OpenFOAM. Validation calculations have been performed for horizontal or nearly horizontal ows, where simulation results have been compared against the local measurement data such as void and temperature or area averaged data delivered by a wire mesh sensor.

Biomolecular condensates: organizers of cellular biochemistry.

Science.gov (United States)

Banani, Salman F; Lee, Hyun O; Hyman, Anthony A; Rosen, Michael K

2017-05-01

Biomolecular condensates are micron-scale compartments in eukaryotic cells that lack surrounding membranes but function to concentrate proteins and nucleic acids. These condensates are involved in diverse processes, including RNA metabolism, ribosome biogenesis, the DNA damage response and signal transduction. Recent studies have shown that liquid-liquid phase separation driven by multivalent macromolecular interactions is an important organizing principle for biomolecular condensates. With this physical framework, it is now possible to explain how the assembly, composition, physical properties and biochemical and cellular functions of these important structures are regulated.

Vortex sorter for Bose-Einstein condensates

International Nuclear Information System (INIS)

Whyte, Graeme; Veitch, John; Courtial, Johannes; Oehberg, Patrik

2004-01-01

We have designed interferometers that sort Bose-Einstein condensates into their vortex components. The Bose-Einstein condensates in the two arms of the interferometer are rotated with respect to each other through fixed angles; different vortex components then exit the interferometer in different directions. The method we use to rotate the Bose-Einstein condensates involves asymmetric phase imprinting and is itself new. We have modeled rotation through fixed angles and sorting into vortex components with even and odd values of the topological charge of two-dimensional Bose-Einstein condensates in a number of states (pure or superposition vortex states for different values of the scattering length). Our scheme may have applications for quantum information processing

Essence of the Vacuum Quark Condensate

International Nuclear Information System (INIS)

Brodsky, Stanley

2010-01-01

We show that the chiral-limit vacuum quark condensate is qualitatively equivalent to the pseudoscalar meson leptonic decay constant in the sense that they are both obtained as the chiral-limit value of well-defined gauge-invariant hadron-to-vacuum transition amplitudes that possess a spectral representation in terms of the current-quark mass. Thus, whereas it might sometimes be convenient to imagine otherwise, neither is essentially a constant mass-scale that fills all spacetime. This means, in particular, that the quark condensate can be understood as a property of hadrons themselves, which is expressed, for example, in their Bethe-Salpeter or light-front wavefunctions.

Energy condensed packaged systems. Composition, production, properties

Directory of Open Access Journals (Sweden)

Igor L. Kovalenko

2015-03-01

Full Text Available In this paper it is presented the substantiation of choice of fuel phase composition and optimal technology of emulsion production on the basis of binary solution of ammonium and calcium nitrates, which provide the obtaining of energy condensed packaged systems with specified properties. The thermal decomposition of energy condensed systems on the basis of ammonium nitrate is investigated. It is shown that the fuel phase of emulsion systems should be based on esters of polyunsaturated acids or on combinations thereof with petroleum products. And ceresin or petroleum wax can be used as the structuring additive. The influence of the technology of energy condensed systems production on the physicochemical and detonation parameters of emulsion explosives is considered. It is shown the possibility of obtaining of emulsion systems with dispersion of 1.3...1.8 microns and viscosity higher than 103 Pa∙s in the apparatus of original design. The sensitizing effect of chlorinated paraffin CP-470 on the thermolysis of energy condensed emulsion system is shown. The composition and production technology of energy condensed packaged emulsion systems of mark Ukrainit-P for underground mining in mines not dangerous on gas and dust are developed.

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.)

Spontaneous formation of quantized vortices in Bose-Einstein condensates

Science.gov (United States)

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

Deepak Condenser Model (DeCoM)

Science.gov (United States)

Patel, Deepak

2013-01-01

Development of the DeCoM comes from the requirement of analyzing the performance of a condenser. A component of a loop heat pipe (LHP), the condenser, is interfaced with the radiator in order to reject heat. DeCoM simulates the condenser, with certain input parameters. Systems Improved Numerical Differencing Analyzer (SINDA), a thermal analysis software, calculates the adjoining component temperatures, based on the DeCoM parameters and interface temperatures to the radiator. Application of DeCoM is (at the time of this reporting) restricted to small-scale analysis, without the need for in-depth LHP component integrations. To efficiently develop a model to simulate the LHP condenser, DeCoM was developed to meet this purpose with least complexity. DeCoM is a single-condenser, single-pass simulator for analyzing its behavior. The analysis is done based on the interactions between condenser fluid, the wall, and the interface between the wall and the radiator. DeCoM is based on conservation of energy, two-phase equations, and flow equations. For two-phase, the Lockhart- Martinelli correlation has been used in order to calculate the convection value between fluid and wall. Software such as SINDA (for thermal analysis analysis) and Thermal Desktop (for modeling) are required. DeCoM also includes the ability to implement a condenser into a thermal model with the capability of understanding the code process and being edited to user-specific needs. DeCoM requires no license, and is an open-source code. Advantages to DeCoM include time dependency, reliability, and the ability for the user to view the code process and edit to their needs.

Characteristics of pressure gradients in downflow condensing of nitrogen in plain, brazed aluminium, plate-fin heat exchanger passages

International Nuclear Information System (INIS)

Robertson, J.M.; Blundell, N.; Clarke, R.H.

1987-01-01

Measurements of the total two-phase gradients have been made during the downflow condensing of nitrogen in a vertical plain, plate-fin test-section. The results show that pressure recovery occurs only at very low qualities, at low mass flux the falling film is smooth and at high mass flux it is rough. A relationship between the apparent film roughness and the calculated film thickness has been established. The implications for designers of heat exchangers are discussed

Comparison of approaches for measuring the mass accommodation coefficient for the condensation of water and sensitivities to uncertainties in thermophysical properties.

Science.gov (United States)

Miles, Rachael E H; Reid, Jonathan P; Riipinen, Ilona

2012-11-08

We compare and contrast measurements of the mass accommodation coefficient of water on a water surface made using ensemble and single particle techniques under conditions of supersaturation and subsaturation, respectively. In particular, we consider measurements made using an expansion chamber, a continuous flow streamwise thermal gradient cloud condensation nuclei chamber, the Leipzig Aerosol Cloud Interaction Simulator, aerosol optical tweezers, and electrodynamic balances. Although this assessment is not intended to be comprehensive, these five techniques are complementary in their approach and give values that span the range from near 0.1 to 1.0 for the mass accommodation coefficient. We use the same semianalytical treatment to assess the sensitivities of the measurements made by the various techniques to thermophysical quantities (diffusion constants, thermal conductivities, saturation pressure of water, latent heat, and solution density) and experimental parameters (saturation value and temperature). This represents the first effort to assess and compare measurements made by different techniques to attempt to reduce the uncertainty in the value of the mass accommodation coefficient. Broadly, we show that the measurements are consistent within the uncertainties inherent to the thermophysical and experimental parameters and that the value of the mass accommodation coefficient should be considered to be larger than 0.5. Accurate control and measurement of the saturation ratio is shown to be critical for a successful investigation of the surface transport kinetics during condensation/evaporation. This invariably requires accurate knowledge of the partial pressure of water, the system temperature, the droplet curvature and the saturation pressure of water. Further, the importance of including and quantifying the transport of heat in interpreting droplet measurements is highlighted; the particular issues associated with interpreting measurements of condensation

Theory of decoherence in Bose-Einstein condensate interferometry

Energy Technology Data Exchange (ETDEWEB)

Dalton, B J [ARC Centre for Quantum-Atom Optics and Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne, Victoria 3122 (Australia)

2007-05-15

A full treatment of decoherence and dephasing effects in BEC interferometry has been developed based on using quantum correlation functions for treating interferometric effects. The BEC is described via a phase space distribution functional of the Wigner type for the condensate modes and the positive P type for the non-condensate modes. Ito equations for stochastic condensate and non-condensate field functions replace the functional Fokker-Planck equation for the distribution functional and stochastic averages of field function products determine the quantum correlation functions.

Interference of an array of independent Bose-Einstein condensates

International Nuclear Information System (INIS)

Hadzibabic, Zoran; Stock, Sabine; Battelier, Baptiste; Bretin, Vincent; Dalibard, Jean

2004-01-01

We have observed high-contrast matter wave interference between 30 Bose-Einstein condensates with uncorrelated phases. Interferences were observed after the independent condensates were released from a one-dimensional optical lattice and allowed to overlap. This phenomenon is explained with a simple theoretical model, which generalizes the analysis of the interference of two condensates

Gas condensate reservoir performance : part 1 : fluid characterization

Energy Technology Data Exchange (ETDEWEB)

Thomas, F.B.; Bennion, D.B. [Hycal Energy Research Laboratories Ltd., Calgary, AB (Canada); Andersen, G. [ChevronTexaco, Calgary, AB (Canada)

2006-07-01

Phase behaviour in gas condensate reservoirs is sensitive to changes in pressure and temperature, which can lead to significant errors in fluid characterization. The challenging task of characterizing in situ fluids in gas condensate reservoirs was discussed with reference to the errors that occur as a result of the complex coupling between phase behavior and geology. This paper presented techniques for reservoir sampling and characterization and proposed methods for minimizing errors. Errors are often made in the classification of dew point systems because engineering criteria does not accurately represent the phase behavior of the reservoir. For example, the fluid of a certain condensate yield may be categorized as a wet gas rather than a retrograde condensate fluid. It was noted that the liquid yield does not dictate whether the fluid is condensate or wet gas, but rather where the reservoir temperature is situated in the pressure temperature phase loop. In order to proceed with a viable field development plan and optimization, the reservoir fluid must be understood. Given that gas productivity decreases with liquid drop out in the near wellbore region, capillary pressure plays a significant role in retrograde reservoirs. It was noted that well understood parameters will lead to a better assessment of the amount of hydrocarbon in place, the rate at which the resource can be produced and optimization strategies as the reservoir matures. It was concluded that multi-rate sampling is the best method to use in sampling fluids since the liquid yield changes as a function of rate. Although bottom-hole sampling in gas condensate reservoirs may be problematic, it should always be performed to address any concerns for liquid-solid separation. Produced fluids typically reveal a specific signature that informs the operator of in situ properties. This paper presented examples that pertain to wet versus retrograde condensate behavior and the presence of an oil zone. The

Magnon Bose-Einstein condensation and spin superfluidity.

Science.gov (United States)

Bunkov, Yuriy M; Volovik, Grigory E

2010-04-28

Bose-Einstein condensation (BEC) is a quantum phenomenon of formation of a collective quantum state in which a macroscopic number of particles occupy the lowest energy state and thus is governed by a single wavefunction. Here we highlight the BEC in a magnetic subsystem--the BEC of magnons, elementary magnetic excitations. The magnon BEC is manifested as the spontaneously emerging state of the precessing spins, in which all spins precess with the same frequency and phase even in an inhomogeneous magnetic field. The coherent spin precession was observed first in superfluid (3)He-B and this domain was called the homogeneously precessing domain (HPD). The main feature of the HPD is the induction decay signal, which ranges over many orders of magnitude longer than is prescribed by the inhomogeneity of magnetic field. This means that spins precess not with a local Larmor frequency, but coherently with a common frequency and phase. This BEC can also be created and stabilized by continuous NMR pumping. In this case the NMR frequency plays the role of a magnon chemical potential, which determines the density of the magnon condensate. The interference between two condensates has also been demonstrated. It was shown that HPD exhibits all the properties of spin superfluidity. The main property is the existence of a spin supercurrent. This spin supercurrent flows separately from the mass current. Transfer of magnetization by the spin supercurrent by a distance of more than 1 cm has been observed. Also related phenomena have been observed: the spin current Josephson effect; the phase-slip processes at the critical current; and the spin current vortex--a topological defect which is the analog of a quantized vortex in superfluids and of an Abrikosov vortex in superconductors; and so on. It is important to mention that the spin supercurrent is a magnetic phenomenon, which is not directly related to the mass superfluidity of (3)He: it is the consequence of a specific

Demonstration of Nautilus Centripetal Capillary Condenser Technology

Science.gov (United States)

Wheeler, RIchard; Tang, Linh; Wambolt, Spencer; Golliher, Eric; Agui, Juan

2016-01-01

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

Gravitino Condensates in the Early Universe and Inflation

CERN Document Server

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...

Mixed fermion-photon condensate in strongly coupled quantum electrodynamics

International Nuclear Information System (INIS)

Gusynin, V.P.; Kushnir, V.A.

1989-01-01

The existence of a new mixed fermion-photon condensate breaking chiral symmetry in strongly coupled phase of quantum electrodynamics is shown. An analytical expression for the renormalized condensate is obtained. 20 refs.; 2 figs

Fermion condensation and gapped domain walls in topological orders

Energy Technology Data Exchange (ETDEWEB)

Wan, Yidun [Department of Physics and Center for Field Theory and Particle Physics, Fudan University,Shanghai 200433 (China); Collaborative Innovation Center of Advanced Microstructures, Nanjing University,Nanjing 210093 (China); Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada); Wang, Chenjie [Perimeter Institute for Theoretical Physics,Waterloo N2L 2Y5, Ontario (Canada)

2017-03-31

We study fermion condensation in bosonic topological orders in two spatial dimensions. Fermion condensation may be realized as gapped domain walls between bosonic and fermionic topological orders, which may be thought of as real-space phase transitions from bosonic to fermionic topological orders. This picture generalizes the previous idea of understanding boson condensation as gapped domain walls between bosonic topological orders. While simple-current fermion condensation was considered before, we systematically study general fermion condensation and show that it obeys a Hierarchy Principle: a general fermion condensation can always be decomposed into a boson condensation followed by a minimal fermion condensation. The latter involves only a single self-fermion that is its own anti-particle and that has unit quantum dimension. We develop the rules of minimal fermion condensation, which together with the known rules of boson condensation, provides a full set of rules for general fermion condensation.

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

Energy Technology Data Exchange (ETDEWEB)

Buschman, Francis X., E-mail: Francis.Buschman@unnpp.gov; Aumiller, David L.

2017-02-15

condensation heat transfer model. In the current work, mass and energy balance equations are solved in a marching scheme in each sub-grid node along the path of the jet trajectory. Jet specific condensation heat transfer closure relations are used. The jet sub-grid method has been implemented as a boundary condition in an in-house version of the sub-channel analysis code COBRA-TF (COBRA-IE). COBRA-IE fluid nodes provide the required vapor and noncondensable gas conditions for the heat transfer solution. The sub-grid model solves the liquid side heat transfer and the condensation rates for each volume in the sub-grid solution. These terms are summed along all of the sub-grid cells that pass through each COBRA-IE control volume to provide mass and energy transfer rates for the COBRA-IE solution. Results using the new jet injection boundary condition show an improved ability to simulate jet condensation experimental data.

Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

International Nuclear Information System (INIS)

Buschman, Francis X.; Aumiller, David L.

2017-01-01

condensation heat transfer model. In the current work, mass and energy balance equations are solved in a marching scheme in each sub-grid node along the path of the jet trajectory. Jet specific condensation heat transfer closure relations are used. The jet sub-grid method has been implemented as a boundary condition in an in-house version of the sub-channel analysis code COBRA-TF (COBRA-IE). COBRA-IE fluid nodes provide the required vapor and noncondensable gas conditions for the heat transfer solution. The sub-grid model solves the liquid side heat transfer and the condensation rates for each volume in the sub-grid solution. These terms are summed along all of the sub-grid cells that pass through each COBRA-IE control volume to provide mass and energy transfer rates for the COBRA-IE solution. Results using the new jet injection boundary condition show an improved ability to simulate jet condensation experimental data.

Mathematical simulation of the process of condensing natural gas

OpenAIRE

Tastandieva G.M.

2015-01-01

Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the...

R404A condensing under forced flow conditions inside smooth, microfin and cross-hatched horizontal tubes

Energy Technology Data Exchange (ETDEWEB)

Infante Ferreira, C A; Nan, X [Delft University of Technology (Netherlands). Laboratory for Refrigeration and Indoor Climate Control; Newell, T A; Chato, J C [University of Illinois, Urbana, IL (United States). Dept. of Mechanical and Industrial Engineering

2003-06-01

Two-phase heat transfer coefficient characteristics of R404A condensing under forced flow conditions inside smooth, microfin and cross-hatched horizontal tubes are experimentally investigated. Experimental parameters include a lubricating polyol ester oil concentration varied from 0 to 4%. The test runs were done at average inlet saturated condensing temperatures of 40{sup o}C. The inlet vapor was kept at saturation (quality = 1.0). The mass fluxes were between 200 and 600 kg/m{sup 2}s, and the heat fluxes were selected to obtain a quality of 0.0 at the outlet of the test section, varying from 5 to 45 kW/m{sup 2}. The heat transfer enhancement factor varied between 1.8 and 2.4 for both microfin and cross-hatched tubes. The larger values applied for larger mass fluxes for the cross-hatched tube and smaller mass fluxes for the microfin tube. Enhancement factors increased as oil concentration increased up to oil concentrations of 2%. For higher oil concentrations the enhancement decreased especially at high mass fluxes, the cross-hatched tube being less sensitive to oil contamination. Pressure drop in the test section increased by approximately 25% as the oil concentration increased from 0 to 4%. The results from the experiments are compared with those calculated from correlations reported in the literature. Moreover, modified correlations for the condensation heat transfer coefficient are proposed for practical applications. (author)

Bioanalysis of underivatized amino acids in non-invasive exhaled breath condensate samples using liquid chromatography coupled with tandem mass spectrometry.

Science.gov (United States)

Konieczna, Lucyna; Pyszka, Magdalena; Okońska, Magdalena; Niedźwiecki, Maciej; Bączek, Tomasz

2018-03-23

Exhaled breath condensate (EBC) is receiving increased attention as a novel, entirely non-invasive technique for collecting biomarker samples. This increased attention is due to the fact that EBC is simple, effort independent, rapid, can be repeated frequently, and can be performed on young children and patients suffering from a variety of diseases. By having a subject breathe tidally through a cooling system for 15-20 min, a sufficient amount of condensate is collected for analysis of biomarkers in clinical studies. However, bioanalysis of EBC involves an unavoidable sample preparation step due to the low concentration of its components. Thus, there is a need for a new and more sensitive analytical method of assessing EBC samples. While researchers have considered analyses of single and small quantities of amino acids - for example, those connected with leukemia - no one has previously attempted to simultaneously analyze a panel of 23 amino acids. Moreover, the present study is well-justified, as prior studies focusing on single amino acids and leukemia at the moment of diagnosis and during chemotherapy (33 days of treatment) are inconsistent. In the present study, amino acids were separated using an XBridge Amide column (3 mm × 100 mm, 3.5 μm). The mobile phase consisted of 10 mM of ammonium buffer in water with a pH of 3 (Phase A) and 10 mM ammonium buffer in acetonitrile (Phase B) under gradient program elution. The analytes were detected in electrospray positive ionization mode. Under optimal conditions, the proposed method exhibited limits of quantification (LOQ) in the range of 0.05-0.5 ng/mL, and good linearity, with the determination coefficient (R 2 ) falling between 0.9904 and 0.9998. The accuracy in human exhaled breath condensate samples ranged between 93.3-113.3% for the 23 studied amino acids, with intra- and inter-day coefficient of variation (CVs) of 0.13-9.92% and 0.17-10.53%, respectively. To demonstrate the liquid

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

In-stack condensible particulate matter measurement and permitting issues

International Nuclear Information System (INIS)

Corio, L.A.; Sherwell, J.

1997-01-01

Based on the results of recent epidemiological studies and assessments of the causes of visibility degradation, EPA is proposing to regulate PM2.5 emissions. PM can be classified as either filterable or condensible PM. Condensible PM includes sulfates, such as sulfuric acid. Sulfates typically account for at least half of the total dry fine PM mass in the atmosphere. Power plant SO x -based emissions make a significant contribution to ambient fine PM levels in the eastern US. Although much of this mass is derived from secondary chemical reactions in the atmosphere, a portion of this sulfate is emitted directly from stacks as condensible PM. The potential condensible PM fraction associated with coal-burning boiler emissions is somewhat uncertain. The characterization of PM emissions from these sources has been, until recently, based on in-stack filterable PM measurements only. To determine the relative magnitude of condensible PM emissions and better understand condensible PM measurement issues, a review and analysis of actual EPA Method 202 results and state-developed hybrid condensible PM methods were conducted. A review of available Method 202 results for several coal-burning boilers showed that the condensible PM, on average, comprises 60% of the total PM10. A review of recent results for state-developed measurement methods for condensible PM for numerous coal-burning boilers indicated that condensible PM accounted for, on average, approximately 49% of total PM. Caution should be exercised in the use of these results because of the seemingly unresolved issue of artifact formation, which may bias the Method 202 and state-developed methods results on the high side. Condensible PM10 measurement results and issues, and potential ramifications of including condensible PM10 emissions in the PSD permit review process are discussed. Selected power plants in Maryland are discussed as examples

Finite temperature effects in Bose-Einstein condensed dark matter halos

International Nuclear Information System (INIS)

Harko, Tiberiu; Madarassy, Enikö J.M.

2012-01-01

Once the critical temperature of a cosmological boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Zero temperature condensed dark matter can be described as a non-relativistic, Newtonian gravitational condensate, whose density and pressure are related by a barotropic equation of state, with barotropic index equal to one. In the present paper we analyze the effects of the finite dark matter temperature on the properties of the dark matter halos. We formulate the basic equations describing the finite temperature condensate, representing a generalized Gross-Pitaevskii equation that takes into account the presence of the thermal cloud. The static condensate and thermal cloud in thermodynamic equilibrium is analyzed in detail, by using the Hartree-Fock-Bogoliubov and Thomas-Fermi approximations. The condensed dark matter and thermal cloud density and mass profiles at finite temperatures are explicitly obtained. Our results show that when the temperature of the condensate and of the thermal cloud are much smaller than the critical Bose-Einstein transition temperature, the zero temperature density and mass profiles give an excellent description of the dark matter halos. However, finite temperature effects may play an important role in the early stages of the cosmological evolution of the dark matter condensates

A hybrid formulation for the numerical simulation of condensed phase explosives

Science.gov (United States)

Michael, L.; Nikiforakis, N.

2016-07-01

In this article we present a new formulation and an associated numerical algorithm, for the simulation of combustion and transition to detonation of condensed-phase commercial- and military-grade explosives, which are confined by (or in general interacting with one or more) compliant inert materials. Examples include confined rate-stick problems and interaction of shock waves with gas cavities or solid particles in explosives. This formulation is based on an augmented Euler approach to account for the mixture of the explosive and its products, and a multi-phase diffuse interface approach to solve for the immiscible interaction between the mixture and the inert materials, so it is in essence a hybrid (augmented Euler and multi-phase) model. As such, it has many of the desirable features of the two approaches and, critically for our applications of interest, it provides the accurate recovery of temperature fields across all components. Moreover, it conveys a lot more physical information than augmented Euler, without the complexity of full multi-phase Baer-Nunziato-type models or the lack of robustness of augmented Euler models in the presence of more than two components. The model can sustain large density differences across material interfaces without the presence of spurious oscillations in velocity and pressure, and it can accommodate realistic equations of state and arbitrary (pressure- or temperature-based) reaction-rate laws. Under certain conditions, we show that the formulation reduces to well-known augmented Euler or multi-phase models, which have been extensively validated and used in practice. The full hybrid model and its reduced forms are validated against problems with exact (or independently-verified numerical) solutions and evaluated for robustness for rate-stick and shock-induced cavity collapse case-studies.

Bose-Einstein condensation in real space

International Nuclear Information System (INIS)

Valencia, J.J.; Llano, M. de; Solis, M.A.

2004-01-01

We show how Bose-Einstein condensation (BEC) occurs not only in momentum space but also in coordinate (or real) space. Analogies between the isotherms of a van der Waals classical gas of extended (or finite-diameter) identical atoms and the point (or zero-diameter) particles of an ideal BE gas allow concluding that, in contrast with the classical case, the volume per particle vanishes in the pure BE condensate phase precisely because the boson diameters are zero. Thus a BE condensate forms in real space without exhibiting a liquid branch as does the classical gas. (Author)

Bose-Einstein condensation and long-range phase coherence in the many-particle Schroedinger wave function

International Nuclear Information System (INIS)

Mayers, J.

2001-01-01

The properties of the many-particle Schroedinger wave function Ψ are examined in the presence of Bose-Einstein condensation (BEC). It is shown that it is possible to define, in terms of Ψ, a function ψ(r-vector vertical bar s-vector), which can be regarded as the single-particle wave function of an arbitrary particle for a fixed configuration s-vector of all other particles. It is shown that ψ(r-vector|s-vector) plays an analogous role to the field operator of standard field-theoretical treatments of superfluidity. It is shown that in the presence of a Bose-Einstein condensate fraction f, ψ(r-vector|s-vector) must be nonzero and phase coherent within at least a fraction f of the total volume of the N-particle system for essentially all s-vector. Examination of the form of variational many-particle wave functions shows that in liquid 4 He, ψ(r-vector|s-vector) extends throughout the spaces left between the hard cores of the other atoms at s-vector. By contrast, in the absence of BEC, ψ(r-vector|s-vector) in the ground state must be nonzero only over a localized region of space. It is shown that in order for long-range phase coherence in ψ(r-vector|s-vector) to be maintained in the presence of velocity fields, any circulation must be quantized over macroscopic length scales. Some numerical calculations of the properties and fluctuations of liquid helium are presented. These suggest that the approach outlined in this paper may have significant advantages for the numerical calculations of the properties of Bose-Einstein condensed systems. The properties of ψ(r-vector|s-vector) are used to show that there is no general connection between the static structure factor and the size of the Bose-Einstein condensate fraction in a Bose fluid. It is suggested that the observed connection in liquid 4 He is due to the creation of vacancies in the liquid structure, which are required so that ψ(r-vector vertical bar s-vector) can delocalize, in the presence of hard

Investigation of the effect of pressure increasing in condensing heat-exchanger

Science.gov (United States)

Murmanskii, I. B.; Aronson, K. E.; Brodov, Yu M.; Galperin, L. G.; Ryabchikov, A. Yu.; Brezgin, D. V.

2017-11-01

The effect of pressure increase was observed in steam condensation in the intermediate coolers of multistage steam ejector. Steam pressure increase for ejector cooler amounts up to 1.5 kPa in the first ejector stage, 5 kPa in the second and 7 kPa in the third one. Pressure ratios are equal to 2.0, 1.3 and 1.1 respectively. As a rule steam velocities at the cooler inlets do not exceed 40…100 m/s and are subsonic in all regimes. The report presents a computational model that describes the effect of pressure increase in the cooler. The steam entering the heat exchanger tears the drops from the condensate film flowing down vertical tubes. At the inlet of heat exchanger the steam flow capturing condensate droplets forms a steam-water mixture in which the sound velocity is significantly reduced. If the flow rate of steam-water mixture in heat exchanger is greater than the sound velocity, there occurs a pressure shock in the wet steam. On the basis of the equations of mass, momentum and energy conservation the authors derived the expressions for calculation of steam flow dryness degree before and after the shock. The model assumes that droplet velocity is close to the velocity of the steam phase (slipping is absent); drops do not come into thermal interaction with the steam phase; liquid phase specific volume compared to the volume of steam is neglected; pressure shock is calculated taking into account the gas-dynamic flow resistance of the tube bundle. It is also assumed that the temperature of steam after the shock is equal to the saturation temperature. The calculations have shown that the rise of steam pressure and temperature in the shock results in dryness degree increase. For calculated flow parameters the velocity value before the shock is greater than the sound velocity. Thus, on the basis of generally accepted physics knowledge the computational model has been formulated for the effect of steam pressure rise in the condensing heat exchanger.

3D Imaging of Water-Drop Condensation on Hydrophobic and Hydrophilic Lubricant-Impregnated Surfaces

Science.gov (United States)

Kajiya, Tadashi; Schellenberger, Frank; Papadopoulos, Periklis; Vollmer, Doris; Butt, Hans-Jürgen

2016-04-01

Condensation of water from the atmosphere on a solid surface is an ubiquitous phenomenon in nature and has diverse technological applications, e.g. in heat and mass transfer. We investigated the condensation kinetics of water drops on a lubricant-impregnated surface, i.e., a micropillar array impregnated with a non-volatile ionic liquid. Growing and coalescing drops were imaged in 3D using a laser scanning confocal microscope equipped with a temperature and humidity control. Different stages of condensation can be discriminated. On a lubricant-impregnated hydrophobic micropillar array these are: (1) Nucleation on the lubricant surface. (2) Regular alignment of water drops between micropillars and formation of a three-phase contact line on a bottom of the substrate. (3) Deformation and bridging by coalescence which eventually leads to a detachment of the drops from the bottom substrate. The drop-substrate contact does not result in breakdown of the slippery behaviour. Contrary, on a lubricant-impregnated hydrophilic micropillar array, the condensed water drops replace the lubricant. Consequently, the surface loses its slippery property. Our results demonstrate that a Wenzel-like to Cassie transition, required to maintain the facile removal of condensed water drops, can be induced by well-chosen surface hydrophobicity.

Analysis study of the condensation heat transfer coefficient in the presence of noncondensable on PCCS vertical condenser tube using MARS-KS

Energy Technology Data Exchange (ETDEWEB)

Choi, Dong jae; Jang, Yeong jun; Lee, Yeon-Gun [Jeju National University, Jeju (Korea, Republic of); Kim, Sin [Chung-Ang University, Seoul (Korea, Republic of)

2015-10-15

The Passive Containment Cooling System (PCCS) to be introduced in advanced LWRs removes released energy to an external heat sink by a naturally driven flow. Containment through the condensation heat transfer phenomenon in the event of the loss of coolant accident (LOCA) or main steam line break (MSLB). As the released steam pressurizes the containment, the PCCS will activate to transport the decay heat In this study, a numerical analysis of the condensation heat transfer coefficients on the PCCS condenser tube is conducted using the MARS-KS code. The condensation heat transfer coefficients are obtained from JNU condensation tests performed on a 1000 long and 40 mm O.D. tube. The analysis condition covers 2 and 4 bar for the air mass fraction ranging from 0.1 to 0.8. The JNU single vertical condensation experimental results, Uchida's and Dehbi's correlation compared with the MARS-KS code's results at 2 and 4 bar. Experimental results and MARS-KS predicted heat transfer coefficient is different from the thermal resistances and Wall subcooling. An average relative error is 18.8% and 15% at 2 and 4 bar, respectively. Uchida's correlation is considered the noncondensable gas mass fraction only. Therefore, that is lower than MARS-KS results at 4 bar. Dehbi's correlation affected by ratio of the height-to-diameter, so its results are higher condensation heat transfer coefficient than MARS-KS predicted results.

Industrial aspects of gas-liquid two-phase flow

International Nuclear Information System (INIS)

Hewitt, G.F.

1977-01-01

The lecture begins by reviewing the various types of plant in which two phase flow occurs. Specifically, boiling plant, condensing plant and pipelines are reviewed, and the various two phase flow problems occurring in them are described. Of course, many other kinds of chemical engineering plant involve two phase flow, but are somewhat outside the scope of this lecture. This would include distillation columns, vapor-liquid separators, absorption towers etc. Other areas of industrial two phase flow which have been omitted for space reasons from this lecture are those concerned with gas/solids, liquid/solid and liquid/liquid flows. There then follows a description of some of the two phase flow processes which are relevant in industrial equipment and where special problems occur. The topics chosen are as follows: (1) pressure drop; (2) horizontal tubes - separation effects non-uniformites in heat transfer coefficient, effect of bends on dryout; (3) multicomponent mixtures - effects in pool boiling, mass transfer effects in condensation and Marangoni effects; (4) flow distribution - manifold problems in single phase flow, separation effects at a single T-junction in two phase flow and distribution in manifolds in two phase flow; (5) instability - oscillatory instability, special forms of instability in cryogenic systems; (6) nucleate boiling - effect of variability of surface, unresolved problems in forced convective nucleate boiling; and (7) shell side flows - flow patterns, cross flow boiling, condensation in cross flow

The effect of the number of condensed phases modeled on aerosol behavior during an induced steam generator tube rupture sequence

International Nuclear Information System (INIS)

Bixler, N.E.; Schaperow, J.H.

1998-06-01

VICTORIA is a mechanistic computer code designed to analyze fission product behavior within a nuclear reactor coolant system (RCS) during a severe accident. It provides detailed predictions of the release of radioactive and nonradioactive materials from the reactor core and transport and deposition of these materials within the RCS. A recently completed independent peer review of VICTORIA, while confirming the overall adequacy of the code, recommended a number of modeling improvements. One of these recommendations, to model three rather than a single condensed phase, is the focus of the work reported here. The recommendation has been implemented as an option so that either a single or three condensed phases can be treated. Both options have been employed in the study of fission product behavior during an induced steam generator tube rupture sequence. Differences in deposition patterns and mechanisms predicted using these two options are discussed

Vector condensate model of electroweak interactions

International Nuclear Information System (INIS)

Cynolter, G.; Pocsik, G.

1997-01-01

Motivated by the fact that the Higgs is not seen, a new version of the standard model is proposed where the scalar doublet is replaced by a vector doublet and its neutral member forms a nonvanishing condensate. Gauge fields are coupled to the new vector fields B in a gauge invariant way leading to mass terms for the gauge fields by condensation. The model is presented and some implications are discussed. (K.A.)

Capillary condensation between disks in two dimensions

DEFF Research Database (Denmark)

Gil, Tamir; Ipsen, John Hjorth

1997-01-01

Capillary condensation between two two-dimensional wetted circular substrates (disks) is studied by an effective free energy description of the wetting interface. The interfacial free-energy potential is developed on the basis of the theory for the wetting of a single disk, where interfacial...... capillary fluctuations play a dominant role. A simple approximative analytical expression of the interfacial free energy is developed and is validated numerically. The capillary condensation is characterized by the analysis of the coverage of the condensed phase, its stability, and asymptotic behaviors...

On the existence of combined condensation of neutral and charged pions in neutron matter

International Nuclear Information System (INIS)

Muto, Takumi; Tatsumi, Toshitaka

1987-01-01

Combined condensation of neutral and charged pions at high-density neutron matter is studied in an approach based on the chiral symmetry. Energy density in the combined π 0 -π c condensed phase to be considered as most energetically favored is derived in a realistic calculation, where we take into account the isobar Δ (1232) degrees of freedom, baryon-baryon short-range correlations described in terms of the Landau-Migdal parameter g', and form factors in the π-baryon vertex. Characteristic features of this phase are discussed in comparison with those of the pure π 0 or the pure π c condensation. The combined π 0 -π c condensed phase sets in at baryon density (3 ∼ 5) times the nuclear density ρ 0 depending on g' after the appearance of the pure π c condensed phase. (author)

Condensed matter physics

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)

Chiral phase transition of three flavor QCD with nonzero magnetic field using standard staggered fermions

Science.gov (United States)

Tomiya, Akio; Ding, Heng-Tong; Mukherjee, Swagato; Schmidt, Christian; Wang, Xiao-Dan

2018-03-01

Lattice simulations for (2+1)-flavor QCD with external magnetic field demon-strated that the quark mass is one of the important parameters responsible for the (inverse) magnetic catalysis. We discuss the dependences of chiral condensates and susceptibilities, the Polyakov loop on the magnetic field and quark mass in three degenerate flavor QCD. The lattice simulations are performed using standard staggered fermions and the plaquette action with spatial sizes Nσ = 16 and 24 and a fixed temporal size Nτ = 4. The value of the quark masses are chosen such that the system undergoes a first order chiral phase transition and crossover with zero magnetic field. We find that in light mass regime, the quark chiral condensate undergoes magnetic catalysis in the whole temperature region and the phase transition tend to become stronger as the magnetic field increases. In crossover regime, deconfinement transition temperature is shifted by the magnetic field when quark mass ma is less than 0:4. The lattice cutoff effects are also discussed.

Effect of non-condensation gas on pressure oscillation of submerged steam jet condensation

International Nuclear Information System (INIS)

Zhao, Quanbin; Cong, Yuelei; Wang, Yingchun; Chen, Weixiong; Chong, Daotong; Yan, Junjie

2016-01-01

Highlights: • Oscillation intensity of steam–air jet increases with rise of water temperature. • Oscillation intensity reduces obviously when air is mixed. • Both first and second dominant frequencies decrease with rise of air mass fraction. • Air has little effect on power of 1st & 2nd frequency bands under low temperature. • The maximum oscillation power occurs under case of A = 1% and T ⩾ 50 °C. - Abstract: The effect of air with low mass fraction on the oscillation intensity and oscillation frequency of a submerged steam jet condensation is investigated under stable condensation region. With air mixing in steam, an obvious dynamic pressure peak appears along the jet direction. The intensity peak increases monotonously with the rise of steam mass flux and water temperature. Peak position moves downstream with the rise of air mass fraction. Moreover, when compared with that of pure steam jet, the oscillation intensity clearly decreases as air is mixed. However, when water temperature is lower than approximately 45 °C, oscillation intensity increases slightly with the rise of air mass fraction, and when water temperature is higher than 55 °C, the oscillation intensity decreases greatly with the rise of air mass fraction. Both the first and second dominant frequencies decrease with rise of air mass fraction. Finally, effect of air mass fractions on the oscillation power of the first and second dominant frequency bands shows similar trends. Under low water temperature, the mixed air has little effect on the oscillation power of both first and second frequency bands. However, when water temperature is high, the oscillation power of both first and second frequency bands appears an obvious peak when air mass fraction is about 1%. With further rise of air mass fraction, the oscillation power decreases gradually.

Study on UF6 condensing receiving system improvement

International Nuclear Information System (INIS)

Zhang Zhenxing; Li Yingfeng; Li Zhenfeng; He Ping; Wang Yanping; Tian Yushan

2012-01-01

In order to improve receiving capacity of UF 6 condensing system, the pressure release mode is changed through modifying gas phase inlet of the first-grade condenser, thus pressure release time is reduced from 13.1 h to 8.1 h. Be- cause of improvement of utility condensers of the two product lines, both the flexibility of feeding nitrogen and the emergency capacity of condensers are improved greatly. And modification of fluid transferring and sampling system make the remains in system transfer flexibly. The practise shows that metal direct recovery rises to the extent, and capacity of the first-grade condensing receiving system improves 8.4%, which strongly guarantees fluorination production safely, continuously and stably run. (authors)

Ultrastructural organization of premature condensed chromosomes at S-phase as observed by atomic force microscopy

International Nuclear Information System (INIS)

Fan Yihui; Zhang Xiaohong; Bai Jing; Mao Renfang; Zhang Chunyu; Lei Qingquan; Fu Songbin

2007-01-01

In this study, we used calyculin A to induce premature condensed chromosomes (PCC). S-phase PCC is as 'pulverized' appearance when viewed by light microscopy. Then, we applied atomic force microscopy (AFM) to investigate the ultrastructual organization of S-phase PCC. S-phase PCC shows ridges and grooves as observed by AFM. After trypsin treatment, chromosome surface roughness is increased and chromosome thickness is decreased. At high magnification, the ridges are composed of densely packed 30 nm chromatin fibers which form chromosome axis. Around the ridges, many 30 nm chromatin fibers radiate from center. Some of the 30 nm chromatin fibers are free ends. The grooves are not real 'gap', but several 30 nm chromatin fibers which connect two ridges and form 'grid' structure. There are four chromatin fibers detached from chromosome: two free straight 30 nm chromatin fibers, one loop chromatin fiber and one straight combining with loop chromatin fiber. These results suggested that the S-phase PCC was high-order organization of 30 nm chromatin fibers and the 30 nm chromatin fibers could exist as loops and free ends

Dark matter as the Bose-Einstein condensation in loop quantum cosmology

International Nuclear Information System (INIS)

Atazadeh, K.; Mousavi, M.; Darabi, F.

2016-01-01

We consider the FLRW universe in a loop quantum cosmological model filled with radiation, baryonic matter (with negligible pressure), dark energy, and dark matter. The dark matter sector is supposed to be of Bose-Einstein condensate type. The Bose-Einstein condensation process in a cosmological context by supposing it as an approximate first-order phase transition, has already been studied in the literature. Here, we study the evolution of the physical quantities related to the early universe description such as the energy density, temperature, and scale factor of the universe, before, during, and after the condensation process. We also consider in detail the evolution era of the universe in a mixed normal-condensate dark matter phase. The behavior and time evolution of the condensate dark matter fraction is also analyzed. (orig.)

Merging of independent condensates: disentangling the Kibble-Zurek mechanism

Science.gov (United States)

Ville, Jean-Loup; Aidelsburger, Monika; Saint-Jalm, Raphael; Nascimbene, Sylvain; Beugnon, Jerome; Dalibard, Jean

2017-04-01

An important step in the study of out-of-equilibrium physics is the Kibble-Zurek theory which describes a system after a quench through a second-order phase transition. This was studied in our group with a temperature quench across the normal-to-superfluid phase transition in an annular trap geometry, inducing the formation of supercurrents. Their magnitude and direction were detected by measuring spiral patterns resulting from the interference of the ring-shaped condensate with a central reference disk. According to the KZ mechanism domains of phase are created during the quench, with a characteristic size depending of its duration. In our case this results in a stochastic formation of supercurrents depending on the relative phases of the domains. As a next step of this study, we now design ourselves the patches thanks to our tunable trapping potential. We control both the number of condensates to be merged (from one to twelve) and their merging time. We report an increase of the vorticity in the ring for an increased number of patches compatible with a random phase model. We further investigate the time required by the phase to homogenize between two condensates.

Finite-momentum condensation in a pumped microcavity

International Nuclear Information System (INIS)

Brierley, R. T.; Eastham, P. R.

2010-01-01

We calculate the absorption spectra of a semiconductor microcavity into which a nonequilibrium exciton population has been pumped. We predict strong peaks in the spectrum corresponding to collective modes analogous to the Cooper modes in superconductors and fermionic atomic gases. These modes can become unstable, leading to the formation of off-equilibrium quantum condensates. We calculate a phase diagram for condensation and show that the dominant instabilities can be at a finite momentum. Thus we predict the formation of inhomogeneous condensates, similar to Fulde-Ferrel-Larkin-Ovchinnikov states.

Advanced Heat/Mass Exchanger Technology for Geothermal and Solar Renewable Energy Systems

Energy Technology Data Exchange (ETDEWEB)

Greiner, Miles [Univ. of Nevada, Reno, NV (United States); Childress, Amy [Univ. of Nevada, Reno, NV (United States); Hiibel, Sage [Univ. of Nevada, Reno, NV (United States); Kim, Kwang [Univ. of Nevada, Reno, NV (United States); Park, Chanwoo [Univ. of Nevada, Reno, NV (United States); Wirtz, Richard [Univ. of Nevada, Reno, NV (United States)

2014-12-16

Northern Nevada has abundant geothermal and solar energy resources, and these renewable energy sources provide an ample opportunity to produce economically viable power. Heat/mass exchangers are essential components to any energy conversion system. Improvements in the heat/mass exchange process will lead to smaller, less costly (more efficient) systems. There is an emerging heat transfer technology, based on micro/nano/molecular-scale surface science that can be applied to heat/mass exchanger design. The objective is to develop and characterize unique coating materials, surface configurations and membranes capable of accommodating a 10-fold increase in heat/mass exchanger performance via phase change processes (boiling, condensation, etc.) and single phase convective heat/mass transfer.

Accretion of Ghost Condensate by Black Holes

Energy Technology Data Exchange (ETDEWEB)

Frolov, A

2004-06-02

The intent of this letter is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as tenth of a solar mass per second for 10MeV-scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

Phase Diagram for Magnon Condensate in Yttrium Iron Garnet Film

Science.gov (United States)

Li, Fuxiang; Saslow, Wayne M.; Pokrovsky, Valery L.

2013-01-01

Recently, magnons, which are quasiparticles describing the collective motion of spins, were found to undergo Bose-Einstein condensation (BEC) at room temperature in films of Yttrium Iron Garnet (YIG). Unlike other quasiparticle BEC systems, this system has a spectrum with two degenerate minima, which makes it possible for the system to have two condensates in momentum space. Recent Brillouin Light Scattering studies for a microwave-pumped YIG film of thickness d = 5 μm and field H = 1 kOe find a low-contrast interference pattern at the characteristic wavevector Q of the magnon energy minimum. In this report, we show that this modulation pattern can be quantitatively explained as due to unequal but coherent Bose-Einstein condensation of magnons into the two energy minima. Our theory predicts a transition from a high-contrast symmetric state to a low-contrast non-symmetric state on varying the d and H, and a new type of collective oscillation. PMID:23455849

Heat transfer during forced convection condensation inside horizontal tube

Energy Technology Data Exchange (ETDEWEB)

Tandon, T.N. [M.M.M. Engineering College, Gorakhpur, Uttar Pradesh (India). Dept. of Mechanical Engineering; Varma, H.K.; Gupta, C.P. [Roorkee Univ., Uttar Pradesh (India). Dept. of Mechanical and Industrial Engineering

1995-03-01

This paper presents the results of an experimental investigation on heat transfer behaviour during forced convection condensation inside a horizontal tube for wavy, semi-annular and annular flows. A qualitative study was made of the effect of various parameters - refrigerant mass flux, vapour quality, condensate film temperature drop and average vapour mass velocity - on average condensing-heat transfer coefficient. Akers-Rosson correlations have been found to predict the heat transfer coefficients within {+-} 25% for the entire range of data. A closer examination of the data revealed that the nature of the relation for the heat transfer coefficient changes from annular and semi-annular flow to wavy flow. Akers-Rosson correlations with changed constant and power have been recommended for the two flow regimes. (author)

Efimov States of Heavy Impurities in a Bose-Einstein Condensate

DEFF Research Database (Denmark)

Zinner, Nikolaj Thomas

2013-01-01

We consider the problem of two heavy impurity particles embedded in a gas of weakly-interacting light mass bosonic particles in the condensed state. Using the Bogoliubov approach to describe the bosonic gas and the Born-Oppenheimer approximation for the three-body dynamics, we calculate the modif......We consider the problem of two heavy impurity particles embedded in a gas of weakly-interacting light mass bosonic particles in the condensed state. Using the Bogoliubov approach to describe the bosonic gas and the Born-Oppenheimer approximation for the three-body dynamics, we calculate...... the modification to the heavy-heavy two-body potential due to the presence of the condensate. For the case of resonant interaction between the light bosons and the impurities, we present (semi)-analytical results for the potential in the limit of a large condensate coherence length. In particular, we find...

Field induced magnetic phase transition as a magnon Bose Einstein condensation

Directory of Open Access Journals (Sweden)

Teodora Radu et al

2007-01-01

Full Text Available We report specific heat, magnetocaloric effect and magnetization measurements on single crystals of the frustrated quasi-2D spin -½ antiferromagnet Cs2CuCl4 in the external magnetic field 0≤B≤12 T along a-axis and in the temperature range 0.03 K≤T≤6 K. Decreasing the applied magnetic field B from high fields leads to the closure of the field induced gap in the magnon spectrum at a critical field Bcsimeq8.44 T and a long-range incommensurate state below Bc. In the vicinity of Bc, the phase transition boundary is well described by the power law TN~(Bc-B1/phi with the measured critical exponent phisimeq1.5. These findings provide experimental evidence that the scaling law of the transition temperature TN can be described by the universality class of 3D Bose–Einstein condensation (BEC of magnons.

Quantitative investigation of free radicals in bio-oil and their potential role in condensed-phase polymerization.

Science.gov (United States)

Kim, Kwang Ho; Bai, Xianglan; Cady, Sarah; Gable, Preston; Brown, Robert C

2015-03-01

We report on the quantitative analysis of free radicals in bio-oils produced from pyrolysis of cellulose, organosolv lignin, and corn stover by EPR spectroscopy. Also, we investigated their potential role in condensed-phase polymerization. Bio-oils produced from lignin and cellulose show clear evidence of homolytic cleavage reactions during pyrolysis that produce free radicals. The concentration of free radicals in lignin bio-oil was 7.5×10(20)  spin g(-1), which was 375 and 138 times higher than free-radical concentrations in bio-oil from cellulose and corn stover. Pyrolytic lignin had the highest concentration in free radicals, which could be a combination of carbon-centered (benzyl radicals) and oxygen-centered (phenoxy radicals) organic species because they are delocalized in a π system. Free-radical concentrations did not change during accelerated aging tests despite increases in molecular weight of bio-oils, suggesting that free radicals in condensed bio-oils are stable. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulation of steam condensation in the presence of noncondensable gases in horizontal condenser tubes using RELAP5 for advanced nuclear reactors

International Nuclear Information System (INIS)

Macedo, Luiz Alberto; Torres, Walmir Maximo

2009-01-01

Horizontal heat exchangers are used in advanced light water nuclear reactors in their passive cooling systems, such as residual heat removal (RHRS) and passive containment cooling system (PCCS). Condensation studies of steam and noncondensable gases mixtures in these heat exchangers are very important due to the phenomena multidimensional nature and the condensate stratification effects. This work presents a comparison between simulation results and experimental data in steady state conditions for some inlet pressure, steam and noncondensable gases (air) inlet mass fractions. The test section is three meters long and consists of two concentric tubes containing pressure, temperature and flow rate sensors. The internal tube, called condenser, contains steam-air mixture flow and external tube is a counter current cooler with water flow rate at low temperature. This test section was modeled and simulations were performed with RELAP5 code. Experimental tests were carried out for 200 to 400 kPa inlet pressure and 5, 10, 15 and 20% of inlet air mass fractions. Comparisons between experimental data and simulation results are presented for 200 and 400 kPa pressure conditions and showed good agreement. However, for 400 kPa inlet steam pressure and inlet air mass fractions above 5%, the simulated temperatures are lower than the experimental data at the final third from the inlet condenser tube, indicating a code overestimation of heat transfer coefficient. New correlations for heat transfer coefficient in these steam-air conditions must be theoretical and experimentally studied and implemented in RELAP5 code for better representing the condensation phenomena. (author)

The influence of N-7 guanine modifications on the strength of Watson-Crick base pairing and guanine N-1 acidity: Comparison of gas-phase and condensed-phase trends

Czech Academy of Sciences Publication Activity Database

Burda, J. V.; Šponer, Jiří; Hrabáková, J.; Zeizinger, M.; Leszczynski, J.

2003-01-01

Roč. 107, č. 22 (2003), s. 5349-5356 ISSN 1520-6106 R&D Projects: GA MŠk ME 517; GA MŠk LN00A016 Grant - others:Wellcome Trust(GB) GR067507MF; ONR(US) N00034-03-1-0116; National Science Foundation(US) CREST 9805465 Institutional research plan: CEZ:AV0Z5004920 Keywords : Watson-Crick base pairing * guanines * gas-phase and condensed-phase trends Subject RIV: BO - Biophysics Impact factor: 3.679, year: 2003

Simulating condensation on microstructured surfaces using Lattice Boltzmann Method

Science.gov (United States)

Alexeev, Alexander; Vasyliv, Yaroslav

2017-11-01

We simulate a single component fluid condensing on 2D structured surfaces with different wettability. To simulate the two phase fluid, we use the athermal Lattice Boltzmann Method (LBM) driven by a pseudopotential force. The pseudopotential force results in a non-ideal equation of state (EOS) which permits liquid-vapor phase change. To account for thermal effects, the athermal LBM is coupled to a finite volume discretization of the temperature evolution equation obtained using a thermal energy rate balance for the specific internal energy. We use the developed model to probe the effect of surface structure and surface wettability on the condensation rate in order to identify microstructure topographies promoting condensation. Financial support is acknowledged from Kimberly-Clark.

Quasiparticle picture of high-temperature superconductors in the frame of a Fermi liquid with the fermion condensate

International Nuclear Information System (INIS)

Amusia, M. Ya.; Shaginyan, V. R.

2001-01-01

A model of a Fermi liquid with the fermion condensate (FC) is applied to the consideration of quasiparticle excitations in high-temperature superconductors, in their superconducting and normal states. Within our model the appearance of the fermion condensate presents a quantum phase transition that separates the regions of normal and strongly correlated electron liquids. Beyond the phase transition point the quasiparticle system is divided into two subsystems, one containing normal quasiparticles and the other-fermion condensate localized at the Fermi surface and characterized by almost dispersionless single-particle excitations. In the superconducting state the quasiparticle dispersion in systems with FC can be presented by two straight lines, characterized by effective masses M FC * and M L * , respectively, and intersecting near the binding energy, which is of the order of the superconducting gap. This same quasiparticle picture persists in the normal state, thus manifesting itself over a wide range of temperatures as new energy scales. Arguments are presented that fermion systems with FC have features of a 'quantum protectorate' [R. B. Laughlin and D. Pines, Proc. Natl. Acad. Sci. U.S.A. >97, 28 (2000); P. W. Anderson, cond-mat/0007185 (unpublished); cond-mat/0007287 (unpublished)

Molecular hydrogen emission from cold condensations in NGC 2440

International Nuclear Information System (INIS)

Reay, N.K.; Walton, N.A.

1988-01-01

Observations are reported of the ν = 1-0 S(1) line of molecular hydrogen in the high-excitation planetary nebula NGC 2440. The emission is particularly strong at the positions of the two bright condensations which lie well within the H II region and close to the position of the very hot T ≅ 350 000 K central star. The emission is consistent with an excited molecular hydrogen mass of ≅ 2-4 x 10 -5 solar mass in the condensations, and the total mass of excited molecular hydrogen associated with the H II region is estimated to be ≅ 6.1 x 10 -3 solar mass. We show that radiation pressure from the central star is insufficient to excite the S(1) line emission. (author)

Condensed matter analogues of cosmology

Science.gov (United States)

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

Bose-Einstein condensates in atomic gases: simple theoretical results

International Nuclear Information System (INIS)

Castin, Y.

2001-01-01

The author presents the theory of the Bose-Einstein condensation along with a discussion of experimental tests. The author deals successively with the following topics: - the ideal Bose gas in a trap (first in a harmonic trap and then in a more general trap), - a model for the atomic interaction, - interacting Bose gas in the Hartree-Fock approximation, - properties of the condensate wavefunction, - the Gross-Pitaevskii equation, - Bogoliubov approach and thermodynamical stability, - phase coherence properties at the Bose-Einstein condensate, and - symmetry-breaking description of condensates. (A.C.)

Numerical modeling of counter-current condensation in a Black Liquor Gasification plant

International Nuclear Information System (INIS)

Risberg, Mikael; Gebart, Rikard

2013-01-01

Pressurized Entrained flow High Temperature Black Liquor Gasification is a novel technique to recover the inorganic chemicals and available energy in black liquor originating from kraft pulping. The gasifier has a direct quench that quickly cools the raw syngas when it leaves the hot reactor by spraying the gas with a water solution. As a result, the raw syngas becomes saturated with steam. Typically the gasifier operates at 30 bar which corresponds to a dew point of about 235 °C and a steam concentration in the saturated syngas that is about 3 times higher than the total concentration of the other species in the syngas. After the quench cooler the syngas is passed through a counter-current condenser where the raw syngas is cooled and most of the steam is condensed. The condenser consists of several vertical tubes where reflux condensation occurs inside the tubes due to water cooling of the tubes on the shell-side. A large part of the condensation takes place inside the tubes on the wall and results in a counterflow of water driven by gravity through the counter current condenser. In this study a computational fluid dynamics model is developed for the two-phase fluid flow on the tube-side of the condenser and for the single phase flow of the shell-side. The two-phase flow was treated using an Euler–Euler formulation with closure correlations for heat flux, condensation rate and pressure drop inside the tubes. The single-phase model for the shell side uses closure correlations for the heat flux and pressure drop. Predictions of the model are compared with results from experimental measurements in a condenser used in a 3 MW Black Liquor Gasification development plant. The results are in good agreement with the limited experimental data that has been collected in the experimental gasifier. However, more validation data is necessary before a definite conclusion can be drawn about the predictive capability of the code. -- Highlights: • A multi-phase model for a

Triplet--Triplet Absorption Spectra of Organic Molecules in Condensed Phases

International Nuclear Information System (INIS)

Carmichael, I.; Hug, G.L.

1986-01-01

We present a compilation of spectral parameters associated with triplet--triplet absorption of organic molecules in condensed media. The wavelengths of maximum absorbance and the corresponding extinction coefficients, where known, have been critically evaluated. Other data, for example, lifetimes, energies and energy transfer rates, relevant to the triplet states of these molecules are included by way of comments but have not been subjected to a similar scrutiny. Work in the gas phase has been omitted, as have theoretical studies. We provide an introduction to triplet state processes in solution and solids, developing the conceptual background and offering an historical perspective on the detection and measurement of triplet state absorption. Techniques employed to populate the triplet state are reviewed and the various approaches to the estimation of the extinction coefficient of triplet--triplet absorption are critically discussed. A statistical analysis of the available data is presented and recommendations for a hierarchical choice of extinction coefficients are made. Data collection is expected to be complete through the end of 1984. Compound name, molecular formula and author indexes are appended

Condensation model for the ESBWR passive condensers

International Nuclear Information System (INIS)

Revankar, S. T.; Zhou, W.; Wolf, B.; Oh, S.

2012-01-01

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

The finite temperature QCD phase transition and the thermodynamic equation of state. An investigation employing lattice QCD with Nf=2 twisted mass quarks

International Nuclear Information System (INIS)

Burger, Florian

2012-01-01

In this thesis we report about an investigation of the finite temperature crossover/phase transition of quantum chromodynamics and the evaluation of the thermodynamic equation of state. To this end the lattice method and the Wilson twisted mass discretisation of the quark action are used. This formulation is known to have an automatic improvement of lattice artifacts and thus an improved continuum limit behaviour. This work presents first robust results using this action for the non-vanishing temperature case. We investigate the chiral limit of the two flavour phase transition with several small values of the pion mass in order to address the open question of the order of the transition in the limit of vanishing quark mass. For the currently simulated pion masses in the range of 300 to 700 MeV we present evidence that the finite temperature transition is a crossover transition rather than a genuine phase transition. The chiral limit is investigated by comparing the scaling of the observed crossover temperature with the mass including several possible scenarios. Complementary to this approach the chiral condensate as the order parameter for the spontaneous breaking of chiral symmetry is analysed in comparison with the O(4) universal scaling function which characterises a second order transition. With respect to thermodynamics the equation of state is obtained from the trace anomaly employing the temperature integral method which provides the pressure and energy density in the crossover region. The continuum limit of the trace anomaly is studied by considering several values of N τ and the tree-level correction technique.

Evaluation of the genotoxic and cytotoxic potential of mainstream whole smoke and smoke condensate from a cigarette containing a novel carbon filter.

Science.gov (United States)

Bombick, D W; Bombick, B R; Ayres, P H; Putnam, K; Avalos, J; Borgerding, M F; Doolittle, D J

1997-09-01

A novel carbon filter has been developed which primarily reduces the amount of certain vapor phase constituents of tobacco smoke with greater efficiency than the charcoal filters of cigarettes currently in the market. In vitro indicators of genotoxic and cytotoxic potential were used to compare the cigarette smoke condensate (particulate phase) or whole cigarette smoke (vapor phase and particulate phase) from cigarettes containing the novel carbon filter with smoke condensate or whole smoke from commercial or prototype cigarettes not containing the novel carbon filter. Ames bacterial mutagenicity, sister chromatid exchange (SCE) in Chinese hamster ovary (CHO) cells, and neutral red cytotoxicity assays in CHO cells were utilized to assess the genotoxic and cytotoxic potential of the cigarette smoke condensates. SCE and neutral red cytotoxicity assays were utilized to assess the genotoxic and cytotoxic potential of the whole smoke. As expected, the novel carbon filter did not significantly affect the genotoxic or cytotoxic activity of the smoke condensate, although we did observe that the use of low-nitrogen tobacco reduced the mutagenicity of the condensate in Salmonella typhimurium strain TA98. However, the whole smoke from cigarettes containing the novel carbon filter demonstrated significant reductions in genotoxic and cytotoxic potential compared to cigarettes without the novel carbon filter. The toxicity of the smoke was correlated (r = 0.7662 for cytotoxicity and r = 0.7562 for SCE induction) to the aggregate mass of several vapor phase components (acetone, acetaldehyde, acrolein, acrylonitrile, 1,3-butadiene, ammonia, NOx, HCN, benzene, isoprene, and formaldehyde) in the smoke of the cigarettes utilized in this study. In conclusion, this novel carbon filter, which significantly reduced the amount of carbonyls and other volatiles in mainstream cigarette smoke, resulted in significant reductions in the genotoxic and cytotoxic activity of the smoke as measured

The quark and gluon condensates in the Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Ebert, D.; Volkov, M.K.

1991-10-01

Systematic study of the role of the nonperturbative gluon condensate arising in a QCD motivated NJL model is presented. The effects of the gluon condensate on meson coupling constants, the pion decay constant, quark condensate and mass formulae are investigated. An interesting result is the decrease of the scale Λ of chiral symmetry breaking. (author). 21 refs

Wettability modified nanoporous ceramic membrane for simultaneous residual heat and condensate recovery

Science.gov (United States)

Hu, H. W.; Tang, G. H.; Niu, D.

2016-06-01

Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

Wettability modified nanoporous ceramic membrane for simultaneous residual heat and condensate recovery.

Science.gov (United States)

Hu, H W; Tang, G H; Niu, D

2016-06-07

Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

A CFD study of wave influence on film steam condensation in the presence of non-condensable gas

Energy Technology Data Exchange (ETDEWEB)

Wang, Xianmao, E-mail: xm-wang11@mails.tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Chang, Huajian, E-mail: changhj@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Corradini, Michael, E-mail: corradini@engr.wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2016-08-15

Highlights: • A condensation model is incorporated in the ANSYS FLUENT. • Different turbulence models are evaluated for flows over wavy surfaces. • Wavy surfaces with and without moving velocities are used to model the wave. • Various wavy surfaces with different wave heights and wavelengths are selected. • Wave influence on film steam condensation is investigated. - Abstract: Steam condensation plays an important role in removing heat from the containment of a nuclear plant during postulated accidents. However, due to the presence of non-condensable gases such as air and hydrogen in the containment, the condensation rate can decrease dramatically. Under certain conditions, the condensate film on the cold containment walls can affect the overall heat transfer rate. The wavy interface of the condensate film is a factor and is usually believed to enhance the condensation rate, since the waves can both increase the interfacial area and disturb the non-condensable gas boundary layer. However, it is not clear how to properly account for this factor and what is its quantitative influence in experiments. In this work, a CFD approach is applied to study the wave effects on film condensation in the presence of non-condensable gas. Wavy surfaces with and without moving velocities are used to replace the wavy interface of the falling film. A condensation model is incorporated in the ANSYS FLUENT simulation and a realizable k–ε turbulence model is applied. Various wavy surfaces with different wave heights and wavelengths are selected to conduct numerical experiments with a wide range of gas velocities. The results show that the wave structure can enhance condensation rate up to ten percent mainly due to the alteration of local flow structures in the gas phase. The increments of the condensation rate due to the wavy interface can vary with different gas velocities. The investigation shows that a multiplication factor accounts for the wave effects on film

Quark condensation, induced symmetry breaking and color superconductivity at high density

International Nuclear Information System (INIS)

Langfeld, Kurt; Rho, Mannque

1999-01-01

The phase structure of hadronic matter at high density relevant to the physics of compact stars and relativistic heavy-ion collisions is studied in a low-energy effective quark theory. The relevant phases that figure are (1) chiral condensation, (2) diquark color condensation (color superconductivity) and (3) induced Lorentz-symmetry breaking (''ISB''). For a reasonable strength for the effective four-Fermi current-current interaction implied by the low-energy effective quark theory for systems with a Fermi surface we find that the ''ISB'' phase sets in together with chiral symmetry restoration (with the vanishing quark condensate) at a moderate density while color superconductivity associated with scalar diquark condensation is pushed up to an asymptotic density. Consequently, color superconductivity seems rather unlikely in heavy-ion collisions although it may play a role in compact stars. Lack of confinement in the model makes the result of this analysis only qualitative but the hierarchy of the transitions we find seems to be quite robust

Condensers

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

Disorder-Induced Order in Two-Component Bose-Einstein Condensates

International Nuclear Information System (INIS)

Niederberger, A.; Schulte, T.; Wehr, J.; Lewenstein, M.; Sanchez-Palencia, L.; Sacha, K.

2008-01-01

We propose and analyze a general mechanism of disorder-induced order in two-component Bose-Einstein condensates, analogous to corresponding effects established for XY spin models. We show that a random Raman coupling induces a relative phase of π/2 between the two BECs and that the effect is robust. We demonstrate it in one, two, and three dimensions at T=0 and present evidence that it persists at small T>0. Applications to phase control in ultracold spinor condensates are discussed

Mathematical simulation of the process of condensing natural gas

Science.gov (United States)

Tastandieva, G. M.

2015-01-01

Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of "cooling down" liquefied natural gas in terms of its partial evaporation with low cost energy.

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.

Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation & Condensation at a Liquid/Vapor Interface

Science.gov (United States)

Stewart, Mark E. M.

2017-01-01

This paper presents an analysis and simulation of evaporation and condensation at a motionless liquid/vapor interface. A 1-D model equation, emphasizing heat and mass transfer at the interface, is solved in two ways, and incorporated into a subgrid interface model within a CFD simulation. Simulation predictions are compared with experimental data from the CPST Engineering Design Unit tank, a cryogenic fluid management test tank in 1-g. The numerical challenge here is the physics of the liquid/vapor interface; pressurizing the ullage heats it by several degrees, and sets up an interfacial temperature gradient that transfers heat to the liquid phase-the rate limiting step of condensation is heat conducted through the liquid and vapor. This physics occurs in thin thermal layers O(1 mm) on either side of the interface which is resolved by the subgrid interface model. An accommodation coefficient of 1.0 is used in the simulations which is consistent with theory and measurements. This model is predictive of evaporation/condensation rates, that is, there is no parameter tuning.

Bose-Einstein Condensation of Long-Lifetime Polaritons in Thermal Equilibrium.

Science.gov (United States)

Sun, Yongbao; Wen, Patrick; Yoon, Yoseob; Liu, Gangqiang; Steger, Mark; Pfeiffer, Loren N; West, Ken; Snoke, David W; Nelson, Keith A

2017-01-06

The experimental realization of Bose-Einstein condensation (BEC) with atoms and quasiparticles has triggered wide exploration of macroscopic quantum effects. Microcavity polaritons are of particular interest because quantum phenomena such as BEC and superfluidity can be observed at elevated temperatures. However, polariton lifetimes are typically too short to permit thermal equilibration. This has led to debate about whether polariton condensation is intrinsically a nonequilibrium effect. Here we report the first unambiguous observation of BEC of optically trapped polaritons in thermal equilibrium in a high-Q microcavity, evidenced by equilibrium Bose-Einstein distributions over broad ranges of polariton densities and bath temperatures. With thermal equilibrium established, we verify that polariton condensation is a phase transition with a well-defined density-temperature phase diagram. The measured phase boundary agrees well with the predictions of basic quantum gas theory.

Condensing species from flue gas in Puertollano gasification power plant, Spain

Energy Technology Data Exchange (ETDEWEB)

Oriol Font; Xavier Querol; Felica Plana; Pilar Coca; Silvia Burgos; Francisco Garcia Pena [Institute of Earth Sciences ' Jaume Almera' , Barcelona (Spain). Environmental Geology

2006-10-15

The occurrence and distribution of trace elements (Pb, Zn, As, Ge, Cd, Tl, Bi, Sn, and also Ni, Fe and V) in condensates arising from coal gasification was investigated through the study of samples physically deposited on the gas cooling system from the Puertollano IGCC 335 MW power plant. These highly metal enriched samples are suitable for a comprehensive evaluation of the mode of occurrence of these elements in IGCC fly ash. Pb, Zn, Ge, and Fe sulfides, Ni-Fe arsenides, Ge and V oxides as well as traces of K chloride and Pb, Zn and Fe sulfates were determined as the major bearing phases for these elements. Three condensation zones were differentiated as function of the condensation temperatures and metal content: 1. Pb zone (520-750{sup o}C), characterized by the dominance of galena (70-90% of the main crystalline phases), and by the condensation of pyrrhotite and nickeline. 2. Ge-Zn-Pb zone (520-470{sup o}C), with sphalerite and wurzite being the dominant crystalline phases (over 40%), and Ge compounds, GeS{sub 2} and GeO{sub 2}, reaching 30% of the bulk condensates. 3. Zn zone (300-400{sup o}C), characterized by the dominance of Zn sulfides (over 85% of the main crystalline phases). The results obtained from these highly metalliferous condensates show similar forms of occurrence for the studied elements to those obtained in the bulk Puertollano IGCC fly ash (by using XAFS spectroscopy), where the contents of these elements are much lower. Furthermore, the sequential condensation of sulfides during coal gasification is similar to that from volcanic fumaroles, and may thus promote a better understanding of volcanic deposits. 23 refs., 7 figs., 5 tabs.

Dynamics of the Bose-Einstein condensate: quasi-one-dimension and beyond

International Nuclear Information System (INIS)

Carr, Lincoln D.; Leung, Mary Ann; Mills College, Oakland, CA 94613-1301; Reinhardt, William P.; Department of Chemistry, University of Washington, Seattle, WA 98195-1700

2000-01-01

It is shown that the quasi-one-dimensional Bose-Einstein condensate is experimentally accessible and rich in intriguing phenomena. We demonstrate numerically and analytically the existence, stability and perturbation-induced dynamics of all types of stationary states of the quasi-one-dimensional nonlinear Schroedinger equation for both repulsive and attractive cases. Among our results are: the connection between stationary states and solitons; creation of vortices from such states; manipulation of such states with simple phase profiles; demonstration of the fragility of the condensate phase in response to shock; and a robust stabilization of the attractive Bose-Einstein condensate. (author)

Thermodynamic entanglement of magnonic condensates

Science.gov (United States)

Yuan, H. Y.; Yung, Man-Hong

2018-02-01

Over the past decade, significant progress has been achieved to create Bose-Einstein condensates (BECs) of magnetic excitations, i.e., magnons, at room temperature, which is a novel quantum many-body system with a strong spin-spin correlation, and contains potential applications in magnonic spintronics. For quantum information science, the magnonic condensates can become an attractive source of quantum entanglement, which plays a central role in most of the quantum information processing tasks. Here we theoretically study the entanglement properties of a magnon gas above and below the condensation temperature. We show that the thermodynamic entanglement of the spins is a manifestation of the off-diagonal long-range order; the entanglement of the condensate does not vanish, even if the spins are separated by an infinitely long distance, which is fundamentally distinct from the normal magnetic ordering below the Curie temperature. In addition, the phase-transition point occurs when the derivative of the entanglement changes abruptly. These results provide a theoretical foundation for a future investigation of the magnon BEC in terms of quantum entanglement.

Orthogonality Catastrophe as a prerequisite for the irreversible decay of the global relative phase of a two-component Bose-Einstein condensate

Science.gov (United States)

Birman, Joseph L.; Kuklov, A. B.

2001-05-01

The concept of the orthogonality catastrophe (OC), which has been introduced previously for one component condensate ( A.B. Kuklov, J.L. Birman, PRA 63), 013609 (2001), is applied to the two-component condensate. The evolution of the global relative phase, which is created by the rf-pulse, is studied under the condition of no exchange of bosons between the components after the pulse. It is shown that the normal component does not induce the OC. Instead, it produces a reversible thermal dephasing, which competes with the quantum phase diffusion (QPD) effect (E.M.Wright, et al, PRL 77), 2158(1996). The thermal dephasing results from the thermal ensemble averaging, and the corresponding dephasing rate is controlled by the two-body interaction and temperature as well as by the closeness to the intrinsic su(2) symmetry, so that no dephasing exists in the case of the exact symmetry (A.B. Kuklov, J.L. Birman, PRL 85), 5488 (2000). The reversible nature of the thermal dephasing as well as of the QPD can be revealed in the atomic echo effect. The role of external noise in erasing the phase memory is discussed as well.

Sakai-Sugimoto model, tachyon condensation and chiral symmetry breaking

International Nuclear Information System (INIS)

Dhar, Avinash; Nag, Partha

2008-01-01

We modify the Sakai-Sugimoto model of chiral symmetry breaking to take into account the open string tachyon which stretches between the flavour D8-branes and D8-bar-branes. There are several reasons of consistency for doing this: (i) Even if it might be reasonable to ignore the tachyon in the ultraviolet where the flavour branes and antibranes are well separated and the tachyon is small, it is likely to condense and acquire large values in the infrared where the branes meet. This takes the system far away from the perturbatively stable minimum of the Sakai-Sugimoto model; (ii) The bifundamental coupling of the tachyon to fermions of opposite chirality makes it a suitable candidate for the quark mass and chiral condensate parameters. We show that the modified Sakai-Sugimoto model with the tachyon present has a classical solution satisfying all the desired consistency properties. In this solution chiral symmetry breaking coincides with tachyon condensation. We identify the parameters corresponding to the quark mass and the chiral condensate and also briefly discuss the mesonic spectra

Gravitationally Unstable Condensations Revealed by ALMA in the TUKH122 Prestellar Core in the Orion A Cloud

Science.gov (United States)

Ohashi, Satoshi; Sanhueza, Patricio; Sakai, Nami; Kandori, Ryo; Choi, Minho; Hirota, Tomoya; Nguyễn-Lu’o’ng, Quang; Tatematsu, Ken’ichi

2018-04-01

We have investigated the TUKH122 prestellar core in the Orion A cloud using ALMA 3 mm dust continuum, N2H+ (J = 1‑0), and CH3OH ({J}K={2}K-{1}K) molecular-line observations. Previous studies showed that TUKH122 is likely on the verge of star formation because the turbulence is almost dissipated and chemically evolved among other starless cores in the Orion A cloud. By combining ALMA 12 m and ACA data, we recover extended emission with a resolution of ∼5″ corresponding to 0.01 pc and identify six condensations with a mass range of 0.1–0.4 M ⊙ and a radius of ≲0.01 pc. These condensations are gravitationally bound following a virial analysis and are embedded in the filament, including the elongated core with a mass of ∼29 M ⊙ and a radial density profile of r ‑1.6 derived by Herschel. The separation of these condensations is ∼0.035 pc, consistent with the thermal Jeans length at a density of 4.4 × 105 cm‑3. This density is similar to the central part of the core. We also find a tendency for the N2H+ molecule to deplete at the dust peak condensation. This condensation may be beginning to collapse because the line width becomes broader. Therefore, the fragmentation still occurs in the prestellar core by thermal Jeans instability, and multiple stars are formed within the TUKH122 prestellar core. The CH3OH emission shows a large shell-like distribution and surrounds these condensations, suggesting that the CH3OH molecule formed on dust grains is released into the gas phase by nonthermal desorption such as photoevaporation caused by cosmic-ray-induced UV radiation.

Condensate cosmology: Dark energy from dark matter

International Nuclear Information System (INIS)

Bassett, Bruce A.; Parkinson, David; Kunz, Martin; Ungarelli, Carlo

2003-01-01

Imagine a scenario in which the dark energy forms via the condensation of dark matter at some low redshift. The Compton wavelength therefore changes from small to very large at the transition, unlike quintessence or metamorphosis. We study cosmic microwave background (CMB), large scale structure, supernova and radio galaxy constraints on condensation by performing a four parameter likelihood analysis over the Hubble constant and the three parameters associated with Q, the condensate field: Ω Q , w f and z t (energy density and equation of state today, and redshift of transition). Condensation roughly interpolates between ΛCDM (for large z t ) and SCDM (low z t ) and provides a slightly better fit to the data than ΛCDM. We confirm that there is no degeneracy in the CMB between H and z t and discuss the implications of late-time transitions for the Lyman-α forest. Finally we discuss the nonlinear phase of both condensation and metamorphosis, which is much more interesting than in standard quintessence models

Accretion of a ghost condensate by black holes

International Nuclear Information System (INIS)

Frolov, Andrei V.

2004-01-01

The intent of this paper is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as a tenth of a solar mass per second for 10 MeV scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model

Optimisation of condenser design in waste immobilisation plants (WIP`s)

Energy Technology Data Exchange (ETDEWEB)

Rajani, G; Ozarde, P D; Gandhi, P M [Waste Management Projects Division, Bhabha Atomic Research Centre, Mumbai (India)

1994-06-01

The situation under study is vertical heat exchanger with steam as the condensing vapour and NO{sub x} gases as the non condensible gas. The presence of even a small quantity of non-condensible gas in the condensible vapour has a profound influence on the resistance to heat transfer in the region of liquid-vapour heat transfer. Heat transfer coefficients go on reducing progressively, making condensers prohibitively bulky and hence optimisation of condensers is necessary for carrying out design calculations. The condenser has been divided into segments and for each segment, momentum and energy equations have been established and solved. Finally the average value for overall mass transfer coefficients has been calculated. Parametric studies giving the influence of sub cooling gases, water temperature, exit temperature etc. have been studied. (author). 5 refs., 5 figs., 2 tabs.

Pair condensation and bound states in fermionic systems

International Nuclear Information System (INIS)

Sedrakian, Armen; Clark, John W.

2006-01-01

We study the finite temperature-density phase diagram of an attractive fermionic system that supports two-body (dimer) and three-body (trimer) bound states in free space. Using interactions characteristic for nuclear systems, we obtain the critical temperature T c2 for the superfluid phase transition and the limiting temperature T c3 for the extinction of trimers. The phase diagram features a Cooper-pair condensate in the high-density, low-temperature domain which, with decreasing density, crosses over to a Bose condensate of strongly bound dimers. The high-temperature, low-density domain is populated by trimers whose binding energy decreases toward the density-temperature domain occupied by the superfluid and vanishes at a critical temperature T c3 >T c2

Condensation Analysis of Steam/Air Mixtures in Horizontal Tubes

International Nuclear Information System (INIS)

Lee, Kwon Yeong; Bae, Sung Won; Kim, Moo Hwan

2008-01-01

Perhaps the most common flow configuration in which a convective condensation occurs is a flow in a horizontal circular tube. This configuration is encountered in air-conditioning and refrigeration condensers as well as condensers in Rankine power cycles. Although a convective condensation is also sometimes contrived to occur in a co-current vertical downward flow, a horizontal flow is often preferred because the flow can be repeatedly passed through the heat exchanger core in a serpentine fashion without trapping liquid or vapor in the return bends. Many researchers have investigated a in-tube condensation for horizontal heat exchangers. However, almost all of them obtained tube section-averaged data without a noncondensable gas. Recently, Wu and Vierow have experimentally studied the condensation of steam in a horizontal heat exchanger with air present. In order to measure the condenser tube inner surface temperatures and to calculate the local heat fluxes, they developed an innovative thermocouple design that allowed for nonintrusive measurements. Here we developed a theoretical model using the heat and mass analogy to analyze a steam condensation with a noncondensable gas in horizontal tubes

Nonlocal Quantum Effects with Bose-Einstein Condensates

International Nuclear Information System (INIS)

Laloee, F.; Mullin, W. J.

2007-01-01

We study theoretically the properties of two Bose-Einstein condensates in different spin states, represented by a double Fock state. Individual measurements of the spins of the particles are performed in transverse directions, giving access to the relative phase of the condensates. Initially, this phase is completely undefined, and the first measurements provide random results. But a fixed value of this phase rapidly emerges under the effect of the successive quantum measurements, giving rise to a quasiclassical situation where all spins have parallel transverse orientations. If the number of measurements reaches its maximum (the number of particles), quantum effects show up again, giving rise to violations of Bell type inequalities. The violation of Bell-Clauser-Horne-Shimony-Holt inequalities with an arbitrarily large number of spins may be comparable (or even equal) to that obtained with two spins

Quantum condensates and topological bosons in coupled light-matter excitations

Energy Technology Data Exchange (ETDEWEB)

Janot, Alexander

2016-02-29

Motivated by the sustained interest in Bose Einstein condensates and the recent progress in the understanding of topological phases in condensed matter systems, we study quantum condensates and possible topological phases of bosons in coupled light-matter excitations, so-called polaritons. These bosonic quasi-particles emerge if electronic excitations (excitons) couple strongly to photons. In the first part of this thesis a polariton Bose Einstein condensate in the presence of disorder is investigated. In contrast to the constituents of a conventional condensate, such as cold atoms, polaritons have a finite life time. Then, the losses have to be compensated by continued pumping, and a non-thermal steady state can build up. We discuss how static disorder affects this non-equilibrium condensate, and analyze the stability of the superfluid state against disorder. We find that disorder destroys the quasi-long range order of the condensate wave function, and that the polariton condensate is not a superfluid in the thermodynamic limit, even for weak disorder, although superfluid behavior would persist in small systems. Furthermore, we analyze the far field emission pattern of a polariton condensate in a disorder environment in order to compare directly with experiments. In the second part of this thesis features of polaritons in a two-dimensional quantum spin Hall cavity with time reversal symmetry are discussed. We propose a topological invariant which has a nontrivial value if the quantum spin Hall insulator is topologically nontrivial. Furthermore, we analyze emerging polaritonic edge states, discuss their relation to the underlying electronic structure, and develop an effective edge state model for polaritons.

Kinetics of mineral condensation in the solar nebula

International Nuclear Information System (INIS)

Grove, T.L.

1987-01-01

A natural extension of the type of gas-mineral-melt condensation experiments is to study the gas-mineral-melt reaction process by controlling the reaction times of appropriate gas compositions with silicate materials. In a condensing and vaporizing gas-solid system, important processes that could influence the composition of and speciation in the gas phase are the kinetics of vaporization of components from silicate crystals and melts. The high vacuum attainable in the space station would provide an environment for studying these processes at gas pressures much lower than those obtainable in experimental devices operated at terrestrial conditions in which the gas phase and mineral or melt would be allowed to come to exchange equilibrium. Further experiments would be performed at variable gas flow rates to simulate disequilibrium vapor fractionation. In this type of experiment it is desirable to analyze directly the species in the gas phase in equilibrium with the condensed silicate material. This analytical method would provide a direct determination of the species present in the gas phase. Currently, the notion of gas speciation is based on calculations from thermodynamic data. The proposed experiments require similar furnace designs and use similar experimental starting compositions, pressures, and temperatures as those described by Mysen

Blockage-induced condensation controlled by a local reaction

Science.gov (United States)

Cirillo, Emilio N. M.; Colangeli, Matteo; Muntean, Adrian

2016-10-01

We consider the setup of stationary zero range models and discuss the onset of condensation induced by a local blockage on the lattice. We show that the introduction of a local feedback on the hopping rates allows us to control the particle fraction in the condensed phase. This phenomenon results in a current versus blockage parameter curve characterized by two nonanalyticity points.

QCD-motivated Nambu-Jona-Lasinio model with quark and gluon condensates

International Nuclear Information System (INIS)

Ebert, D.; Volkov, M.K.

1991-01-01

We present a systematic study of the role of the nonperturbative gluon condensate arising in a QCD-motivated NJL model. The effects of the gluon condensate on induced meson couplings, the pion decay constant, quark condensate and mass formulae are investigated. An interesting result is the change of the scale Λ of chiral symmetry breaking and of the universal four-quark coupling κ. (orig.)

Quantum chemical approach for condensed-phase thermochemistry (V): Development of rigid-body type harmonic solvation model

Science.gov (United States)

Tarumi, Moto; Nakai, Hiromi

2018-05-01

This letter proposes an approximate treatment of the harmonic solvation model (HSM) assuming the solute to be a rigid body (RB-HSM). The HSM method can appropriately estimate the Gibbs free energy for condensed phases even where an ideal gas model used by standard quantum chemical programs fails. The RB-HSM method eliminates calculations for intra-molecular vibrations in order to reduce the computational costs. Numerical assessments indicated that the RB-HSM method can evaluate entropies and internal energies with the same accuracy as the HSM method but with lower calculation costs.

Vector condensate and AdS soliton instability induced by a magnetic field

International Nuclear Information System (INIS)

Cai, Rong-Gen; Li, Li; Li, Li-Fang; Wu, You

2014-01-01

We continue to study the holographic p-wave superconductor model in the Einstein-Maxwell-complex vector field theory with a non-minimal coupling between the complex vector field and the Maxwell field. In this paper we work in the AdS soliton background which describes a conformal field theory in the confined phase and focus on the probe approximation. We find that an applied magnetic field can lead to the condensate of the vector field and the AdS soliton instability. As a result, a vortex lattice structure forms in the spatial directions perpendicular to the applied magnetic field. As a comparison, we also discuss the vector condensate in the Einstein-SU(2) Yang-Mills theory and find that in the setup of the present paper, the Einstein-Maxwell-complex vector field model is a generalization of the SU(2) model in the sense that the vector field has a general mass and gyromagnetic ratio

Condensation heat transfer on natural convection at the high pressure

International Nuclear Information System (INIS)

Jong-Won, Kim; Hyoung-Kyoun, Ahn; Goon-Cherl, Park

2007-01-01

The Regional Energy Research Institute for the Next Generation is to develop a small scale electric power system driven by an environment-friendly and stable small nuclear reactor. REX-10 has been developed to assure high system safety in order to be placed in densely populated region and island. REX-10 adopts the steam-gas pressurizer to assure the inherent safety. The thermal-hydraulic phenomena in the steam-gas pressurizer are very complex. Especially, the condensation heat transfer with noncondensable gas on the natural convection is important to evaluate the pressurizer behavior. However, there have been few investigations on the condensation in the presence of noncondensable gas at the high pressure. In this study, the theoretical model is developed to estimate the condensation heat transfer at the high pressure using heat and mass transfer analogy. The analysis results show good agreement with correlations and experimental data. It is found that the condensation heat transfer coefficient increases as the total pressure increases or the mass fraction of the non-condensable gas decreases. In addition, the heat transfer coefficient no more increases over the specific pressure

Coexistence of hyperon and π condensation in neutron stars

International Nuclear Information System (INIS)

Isshiki, Akinori

2000-01-01

We consider the coexistence of hyperon and π condensation in neutron stars. The coexistence phase may occur because of the strong ΛΣπ coupling. Hyperon can appear under π condensation, because short range repulsion reduce the π-baryon p wave attraction. The system approaches the Fermi gas because of this reduction. (author)

Condensation of the steam in the horizontal steam line during cold water flooding

International Nuclear Information System (INIS)

Strubelj, L.; Tiselj, I.

2006-01-01

Direct contact condensation and condensation induced water-hammer in a horizontal pipe was experimentally investigated at PMK-2 test facility of the Hungarian Atomic Energy Research Institute KFKI. The experiment is preformed in the horizontal section of the steam line of the PMK-2 integral test facility. As liquid water floods the horizontal part of the pipeline, the counter current horizontally stratified flow is being observed. During the flooding of the steam line, the vapour-liquid interface area increases and therefore the vapour condensation rate and the vapour velocity also increase. Similar phenomena can occur in the cold/hot leg of the primary loop of PWR nuclear power plant during loss of coolant accident, when emergency core cooling system is activated. Water level at one cross-section and four local void fraction and temperature at the top of steam line was measured and compared with simulation. Condensed steam increases the water temperature that is why the local temperature measurements are the most important information, from which condensation rate can be estimated, since mass of condensed steam was not measured. Free surface simulation of the experiment with thermal phase change model is presented. Surface renewal concept with small eddies is used for calculation of heat transfer coefficient. With surface renewal theory we did not get results similar to experiment, that is why heat transfer coefficient was increased by factor 20. In simulation with heat transfer coefficient calculated with surface renewal concept bubble entrapment is due to reflection of the wave from the end of the pipe. When heat transfer coefficient is increased, condensation rate and steam velocity are also increased, bubble entrapment is due to Kelvin-Helmholtz instability of the free surface, and the results become similar to the measurements. (author)

Transition from condensation-induced counter-current flow to dispersed flow

International Nuclear Information System (INIS)

Gale, J.; Tiselj, I.

2004-01-01

Model of transition from the horizontally stratified condensation-induced counter-current flow to slug flow has been analyzed with computer code WAHA and compared to the experimental data obtained in the steamline of the PMK2 test facility of Hungarian Atomic Energy Institute. The experiment was performed in the steamline initially filled with hot vapor that was gradually flooded with cold liquid. Successful simulation of the condensation-induced water hammer that follows the transition, requires accurate description of the horizontally stratified and slug flow regimes and criteria for transition between both flow regimes. Current version of the WAHA code, not verified for the condensation induced type of the water hammer, predicts the water-hammer pressure peak that exceeds 600 bar, while the measured pressure is p m = 170 ± 50 bar. Sensitivity analysis of the inter-phase exchange terms and transition conditions, pointed to the most important closure relations for heat, mass and momentum transfer. The main conclusion of the analysis is large uncertainty of the simulations: minor modification of the crucial correlations can lead to a severe water-hammer in one case, or to the 'calm' transient without pressure peaks in the other case. Large uncertainty is observed in experiments. The same simulation was performed also with RELAP5 code. However, no water hammer was predicted. (author)

Synchronous Condenser Allocation for Improving System Short Circuit Ratio

DEFF Research Database (Denmark)

Jia, Jundi; Yang, Guangya; Nielsen, Arne Hejde

2018-01-01

With converter-based renewable energy sources increasingly integrated into power systems and conventional power plants gradually phased out, future power systems will experience reduced short circuit strength. The deployment of synchronous condensers can serve as a potential solution. This paper...... presents an optimal synchronous condenser allocation method for improving system short circuit ratio at converter point of common coupling using a modified short circuit analysis approach. The total cost of installing new synchronous condensers is minimized while the system short circuit ratios...

Comparative study during condensation of R152 a and R134 a with presence of non-condensable gas inside a vertical tube

Science.gov (United States)

Charef, Adil; Feddaoui, M'barek; Najim, Monssif; Meftah, Hicham

2018-04-01

A computational study of the liquid film condensation from vapour-gas mixtures of HFC refrigerants inside a vertical tube is performed. The external wall of the tube is subjected to constant temperature. The model uses an implicit finite difference method to solve the governing equations for the liquid film and gas flow together including the boundary and interfacial matching conditions. Parametric computations were realised to examine the effects of inlet Reynolds number, tube length, and inlet temperature of the gas mixtures on the condensation mechanism. A comparative study between the results obtained for studied R152 a and R134 a with presence of non-condensable gas is made. The predicted results indicate that the condensation of R152 a-air corresponds to a higher accumulated condensation m c d and local heat transfer coefficient h T when compared to R134 a-air in the same conditions. Increasing the inlet Reynolds number or the tube length improve the condensation. Additionally, lower non-condensable gas in R152 a - a i r substantially enhances the heat and mass exchanges.

Mathematical simulation of the process of condensing natural gas

Directory of Open Access Journals (Sweden)

Tastandieva G.M.

2015-01-01

Full Text Available Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of “cooling down” liquefied natural gas in terms of its partial evaporation with low cost energy.

Condensation in models with factorized and pair-factorized stationary states

International Nuclear Information System (INIS)

Evans, M R; Waclaw, B

2015-01-01

Non-equilibrium real-space condensation is a phenomenon in which a finite fraction of some conserved quantity (mass, particles, etc) becomes spatially localized. We review two popular stochastic models of hopping particles that lead to condensation and whose stationary states assume a factorized form: the zero-range process and the misanthrope process, and their various generalizations. We also introduce a new model—a misanthrope process with parallel dynamics—that exhibits condensation and has a pair-factorized stationary state

Quasiparticle picture of high-temperature superconductors in the frame of a Fermi liquid with the fermion condensate

Energy Technology Data Exchange (ETDEWEB)

Amusia, M. Ya.; Shaginyan, V. R.

2001-06-01

A model of a Fermi liquid with the fermion condensate (FC) is applied to the consideration of quasiparticle excitations in high-temperature superconductors, in their superconducting and normal states. Within our model the appearance of the fermion condensate presents a quantum phase transition that separates the regions of normal and strongly correlated electron liquids. Beyond the phase transition point the quasiparticle system is divided into two subsystems, one containing normal quasiparticles and the other{emdash}fermion condensate localized at the Fermi surface and characterized by almost dispersionless single-particle excitations. In the superconducting state the quasiparticle dispersion in systems with FC can be presented by two straight lines, characterized by effective masses M{sub FC}{sup *} and M{sub L}{sup *}, respectively, and intersecting near the binding energy, which is of the order of the superconducting gap. This same quasiparticle picture persists in the normal state, thus manifesting itself over a wide range of temperatures as new energy scales. Arguments are presented that fermion systems with FC have features of a {open_quotes}quantum protectorate{close_quotes} [R. B. Laughlin and D. Pines, Proc. Natl. Acad. Sci. U.S.A. >97, 28 (2000); P. W. Anderson, cond-mat/0007185 (unpublished); cond-mat/0007287 (unpublished)].

Investigation of Interfacial Phenomena During Condensation of Humid Air on a Horizontal Substrate

Directory of Open Access Journals (Sweden)

Tiwari Akhilesh

2013-12-01

Full Text Available The condensation phenomenon of humid air on solid substrates can occur in many applications, and it is known as one of the most difficult problem to deal with for the improvement of the quality of air in a closed environment. The present study was motivated by the investigation of the coupling between ventilation and condensation inside controlled ecological life support systems (CELSS, as it has an important role for higher plants growth in greenhouses and living conditions in manned spacecraft cabins, particularly in long duration space flights or in future space bases. It is well known that the enhancement of the gas exchange with leaves and the growth of plants are dependent on the organoleptic and/or the surrounding thermo-physical factors. Insufficient air movement around plants and condensation on plant leaves generally limit their growth by suppressing the gas diffusion in the leaf boundary-layer thereby decreasing photosynthetic and transpiration rates. Thus, the optimization of a CELSS will require the control of the airflow and concomitant gas/liquid transfer at the plant surfaces. The experimental and theoretical modeling of CELSS requires a comprehensive understanding of the micro to the macro levels of liquid gas phase transfer. Hence, an experimental set-up was developed at 1-g to evaluate the mass transfer coefficients due to condensation of humid air on specific geometries in well controlled environmental conditions. The goal was to establish correlations between the fluxes of mass and heat, the relative humidity and the mean flow for the development of theoretical models based on local transfer coefficients. The experiments were performed at ambient temperature, with a relative humidity between 35-70% and for a velocity range of 1.0-3.0 m.s−1.

HPLC, NMR and MALDI-TOF MS analysis of condensed tannins from Lithocarpus glaber leaves with potent free radical scavenging activity.

Science.gov (United States)

Zhang, Liang Liang; Lin, Yi Ming

2008-12-04

Using acid-catalyzed degradation in the presence of cysteamine, the condensed tannins from Lithocarpus glaber leaves were characterized, following thiolysis, by means of reversed-phase HPLC, 13C-NMR and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analyses. The thiolysis reaction products showed the presence of the procyanidin (PC) and prodelphinidin (PD) structures. The 13C-NMR spectrum revealed that the condensed tannins were comprised of PD (72.4%) and PC (27.6%), and with a greater content of cis configuration rather than the trans configuration of C2-C3. The MALDI-TOF MS analysis proved the presence of PD units, and the maximum degree of polymerization (DP) was an undecamer. The antioxidant activity of condensed tannins from L. glaber leaves was evaluated by using a free radical scavenging activity assay.

Advances in high pressure research in condensed matter: proceedings of the international conference on condensed matter under high pressures

International Nuclear Information System (INIS)

Sikka, S.K.; Gupta, Satish C.; Godwal, B.K.

1997-01-01

The use of pressure as a thermodynamic variable for studying condensed matter has become very important in recent years. Its main effect is to reduce the volume of a substance. Thus, in some sense, it mimics the phenomena taking place during the cohesion of solids like pressure ionization, modifications in electronic properties and phase changes etc. Some of the phase changes under pressure lead to synthesis of new materials. The recent discovery of high T c superconductivity in YBa 2 Cu 3 O 7 may be indirectly attributed to the pressure effect. In applied fields like simulation of reactor accident, design of inertial confinement fusion schemes and for understanding the rock mechanical effects of shock propagation in earth due to underground nuclear explosions, the pressure versus volume relations of condensed matter are a vital input. This volume containing the proceedings of the International Conference on Condensed Matter Under High Pressure covers various aspects of high pressure pertaining to equations of state, phase transitions, electronic, optical and transport properties of solids, atomic and molecular studies, shock induced reactions, energetic materials, materials synthesis, mineral physics, geophysical and planetary sciences, biological applications and food processing and advances in experimental techniques and numerical simulations. Papers relevant to INIS are indexed separately

From cation to oxide: hydroxylation and condensation of aqueous complexes

International Nuclear Information System (INIS)

Jolivet, J.P.

1997-01-01

Hydroxylation, condensation and precipitation of metal cations in aqueous solution are briefly reviewed. Hydroxylation of aqueous complexes essentially depends on the format charge (oxidation state), the size and the pH of the medium. It is the step allowing the condensation reaction. Depending on the nature of complexes (aqua-hydroxo, oxo-hydroxo), the. mechanism of condensation is different, olation or ox-olation respectively. The first one leads to poly-cations or hydroxides more or less stable against dehydration. The second one leads to poly-anions or oxides. Oligomeric species (poly-cations, poly-anions) are form from charged monomer complexes while the formation of solid phases requires non-charged precursors. Because of their high lability, charged oligomers are never the precursors of solids phases. The main routes for the formation of solid phases from solution are studied with two important and representative elements, Al and Si. For Al 3+ ions, different methods (base addition in solution, thermo-hydrolysis, hydrothermal synthesis) are discussed in relation to the crystal structure of the solid phase obtained. For silicic species condensing by ox-olation, the role of acid or base catalysis on the morphology of gels is studied. The influence of complexing ligands on the processes and on the characteristics of solids (morphology of particles, basic salts and polymetallic oxides formation) is studied. (author)

Reflection Patterns Generated by Condensed-Phase Oblique Detonation Interaction with a Rigid Wall

Science.gov (United States)

Short, Mark; Chiquete, Carlos; Bdzil, John; Meyer, Chad

2017-11-01

We examine numerically the wave reflection patterns generated by a detonation in a condensed phase explosive inclined obliquely but traveling parallel to a rigid wall as a function of incident angle. The problem is motivated by the characterization of detonation-material confiner interactions. We compare the reflection patterns for two detonation models, one where the reaction zone is spatially distributed, and the other where the reaction is instantaneous (a Chapman-Jouguet detonation). For the Chapman-Jouguet model, we compare the results of the computations with an asymptotic study recently conducted by Bdzil and Short for small detonation incident angles. We show that the ability of a spatially distributed reaction energy release to turn flow streamlines has a significant impact on the nature of the observed reflection patterns. The computational approach uses a shock-fit methodology.

Condensates in quantum chromodynamics and the cosmological constant

Science.gov (United States)

Brodsky, Stanley J.; Shrock, Robert

2011-01-01

Casher and Susskind [Casher A, Susskind L (1974) Phys Rev 9:436–460] have noted that in the light-front description, spontaneous chiral symmetry breaking is a property of hadronic wavefunctions and not of the vacuum. Here we show from several physical perspectives that, because of color confinement, quark and gluon condensates in quantum chromodynamics (QCD) are associated with the internal dynamics of hadrons. We discuss condensates using condensed matter analogues, the Anti de Sitter/conformal field theory correspondence, and the Bethe–Salpeter–Dyson–Schwinger approach for bound states. Our analysis is in agreement with the Casher and Susskind model and the explicit demonstration of “in-hadron” condensates by Roberts and coworkers [Maris P, Roberts CD, Tandy PC (1998) Phys Lett B 420:267–273], using the Bethe–Salpeter–Dyson–Schwinger formalism for QCD-bound states. These results imply that QCD condensates give zero contribution to the cosmological constant, because all of the gravitational effects of the in-hadron condensates are already included in the normal contribution from hadron masses.

Condensation phenomena in two-flavor scalar QED at finite chemical potential

CERN Document Server

Schmidt, Alexander; Gattringer, Christof

2014-01-01

We study condensation in two-flavored, scalar QED with non-degenerate masses at finite chemical potential. The conventional formulation of the theory has a sign problem at finite density which can be solved using an exact reformulation of the theory in terms of dual variables. We perform a Monte Carlo simulation in the dual representation and observe a condensation at a critical chemical potential $\\mu_c$. After determining the low-energy spectrum of the theory we try to establish a connection between $\\mu_c$ and the mass of the lightest excitation of the system, which are naively expected to be equal. It turns out, however, that the relation of the critical chemical potential to the mass spectrum in this case is non-trivial: Taking into account the form of the condensate and making some simplifying assumptions we suggest an adequate explanation which is supported by numerical results.

A macrothermodynamic approach to the limit of reversible capillary condensation.

Science.gov (United States)

Trens, Philippe; Tanchoux, Nathalie; Galarneau, Anne; Brunel, Daniel; Fubini, Bice; Garrone, Edoardo; Fajula, François; Di Renzo, Francesco

2005-08-30

The threshold of reversible capillary condensation is a well-defined thermodynamic property, as evidenced by corresponding states treatment of literature and experimental data on the lowest closure point of the hysteresis loop in capillary condensation-evaporation cycles for several adsorbates. The nonhysteretical filling of small mesopores presents the properties of a first-order phase transition, confirming that the limit of condensation reversibility does not coincide with the pore critical point. The enthalpy of reversible capillary condensation can be calculated by a Clausius-Clapeyron approach and is consistently larger than the condensation heat in unconfined conditions. Calorimetric data on the capillary condensation of tert-butyl alcohol in MCM-41 silica confirm a 20% increase of condensation heat in small mesopores. This enthalpic advantage makes easier the overcoming of the adhesion forces by the capillary forces and justifies the disappearing of the hysteresis loop.

The effect of the condensed-phase environment on the vibrational frequency shift of a hydrogen molecule inside clathrate hydrates.

Science.gov (United States)

Powers, Anna; Scribano, Yohann; Lauvergnat, David; Mebe, Elsy; Benoit, David M; Bačić, Zlatko

2018-04-14

We report a theoretical study of the frequency shift (redshift) of the stretching fundamental transition of an H 2 molecule confined inside the small dodecahedral cage of the structure II clathrate hydrate and its dependence on the condensed-phase environment. In order to determine how much the hydrate water molecules beyond the confining small cage contribute to the vibrational frequency shift, quantum five-dimensional (5D) calculations of the coupled translation-rotation eigenstates are performed for H 2 in the v=0 and v=1 vibrational states inside spherical clathrate hydrate domains of increasing radius and a growing number of water molecules, ranging from 20 for the isolated small cage to over 1900. In these calculations, both H 2 and the water domains are treated as rigid. The 5D intermolecular potential energy surface (PES) of H 2 inside a hydrate domain is assumed to be pairwise additive. The H 2 -H 2 O pair interaction, represented by the 5D (rigid monomer) PES that depends on the vibrational state of H 2 , v=0 or v=1, is derived from the high-quality ab initio full-dimensional (9D) PES of the H 2 -H 2 O complex [P. Valiron et al., J. Chem. Phys. 129, 134306 (2008)]. The H 2 vibrational frequency shift calculated for the largest clathrate domain considered, which mimics the condensed-phase environment, is about 10% larger in magnitude than that obtained by taking into account only the small cage. The calculated splittings of the translational fundamental of H 2 change very little with the domain size, unlike the H 2 j = 1 rotational splittings that decrease significantly as the domain size increases. The changes in both the vibrational frequency shift and the j = 1 rotational splitting due to the condensed-phase effects arise predominantly from the H 2 O molecules in the first three complete hydration shells around H 2 .

The effect of the condensed-phase environment on the vibrational frequency shift of a hydrogen molecule inside clathrate hydrates

Science.gov (United States)

Powers, Anna; Scribano, Yohann; Lauvergnat, David; Mebe, Elsy; Benoit, David M.; Bačić, Zlatko

2018-04-01

We report a theoretical study of the frequency shift (redshift) of the stretching fundamental transition of an H2 molecule confined inside the small dodecahedral cage of the structure II clathrate hydrate and its dependence on the condensed-phase environment. In order to determine how much the hydrate water molecules beyond the confining small cage contribute to the vibrational frequency shift, quantum five-dimensional (5D) calculations of the coupled translation-rotation eigenstates are performed for H2 in the v =0 and v =1 vibrational states inside spherical clathrate hydrate domains of increasing radius and a growing number of water molecules, ranging from 20 for the isolated small cage to over 1900. In these calculations, both H2 and the water domains are treated as rigid. The 5D intermolecular potential energy surface (PES) of H2 inside a hydrate domain is assumed to be pairwise additive. The H2-H2O pair interaction, represented by the 5D (rigid monomer) PES that depends on the vibrational state of H2, v =0 or v =1 , is derived from the high-quality ab initio full-dimensional (9D) PES of the H2-H2O complex [P. Valiron et al., J. Chem. Phys. 129, 134306 (2008)]. The H2 vibrational frequency shift calculated for the largest clathrate domain considered, which mimics the condensed-phase environment, is about 10% larger in magnitude than that obtained by taking into account only the small cage. The calculated splittings of the translational fundamental of H2 change very little with the domain size, unlike the H2 j = 1 rotational splittings that decrease significantly as the domain size increases. The changes in both the vibrational frequency shift and the j = 1 rotational splitting due to the condensed-phase effects arise predominantly from the H2O molecules in the first three complete hydration shells around H2.

Coherence properties of exciton polariton OPO condensates in one and two dimensions

International Nuclear Information System (INIS)

Spano, R; Cuadra, J; Tosi, G; Antón, C; Lingg, C A; Sanvitto, D; Martín, M D; Viña, L; Eastham, P R; Van der Poel, M; Hvam, J M

2012-01-01

We give an overview of the coherence properties of exciton-polariton condensates generated by optical parametric scattering. Different aspects of the first-order coherence (g (1) ) have been investigated. The spatial coherence extension of a two-dimensional (2D) polariton system, below and at the parametric threshold, demonstrates the development of a constant phase coherence over the entire condensate, once the condensate phase transition takes place. The effect on coherence of the photonic versus excitonic nature of the condensates is also examined. The coherence of a quasi-1D trap, composed of a line defect, is studied, showing the detrimental effect of reduced dimensionality on the establishment of the long range order. In addition, the temporal coherence decay, g (1) (τ), reveals a fast decay in contrast with the 2D case. The situation of a quasi-1D condensate coexisting with a 2D one is also presented. (paper)

Numerical Analysis of Solitary Wave Influence on the Film-wise Condensation in Presence of Non-Condensable Gases

International Nuclear Information System (INIS)

Krzysztof Karkoszka; Henryk Anglart

2006-01-01

This paper is dealing with the analysis of condensation in presence of non-condensable gas on a laminar liquid film falling down on a vertical smooth surface. Particular interest is focused on the influence of solitary waves on the condensation process. Solutions to the pressure, velocity, temperature and additional scalar variable fields are obtained numerically by solving two -- dimensional Navier - Stokes equations formulated in a general coordinate system and applying the artificial compressibility method. The whole system of equations together with adequate boundary conditions is implemented using the finite difference method and solved in the Matlab R code. Both implicit Crank - Nicolson and Euler schemes for the time derivatives are initially used and the latter one is chosen as a more stable. All computations are carried out with prescribed geometry for a film and gas domains and a special attention is focused mainly on the modelling of the influence of the interfacial boundary conditions on the heat transfer process between gaseous mixture and liquid phases. Description of the physical, mathematical and numerical models and several examples of the solutions are presented. Conclusions on the wave hydrodynamics influence on the heat transfer during phase change process are drawn. (authors)

QCD-motivated Nambu-Jona-Lasinio model with quark and gluon condensates

International Nuclear Information System (INIS)

Ebert, D.; Volkov, M.K.

1991-01-01

A systematic study of the role of the nonperturbative gluon condensate arising in a QCD-motivated Nambu-Jona-Lasinio model is presented. The effects of the gluon condensate on induced meson couplings, the pion decay constant, quark condensate and mass formulae are investigated. An interesting result is the change of the scale Λ of chiral symmetry breaking and of the universal four-quark coupling constant κ. 20 refs

q-bar q condensate for light quarks beyond the chiral limit

International Nuclear Information System (INIS)

Williams, R.; Fischer, C.S.; Pennington, M.R.

2007-01-01

We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate

Application of mixture length turbulence models in the domain of condensation; Application des modeles de turbulence de longueur de melange dans le domaine de la condensation

Energy Technology Data Exchange (ETDEWEB)

Louahlia, H.; Panday, P.K. [Institut de Genie Energetique, 90 - Belfort (France)

1997-12-31

This paper presents a comparison between turbulence models based on Prandtl theory and applied to the problem of pure fluids condensation. A theoretical model is defined which allows to determine the physical characteristics of condensation between two vertical or horizontal flat plates. The total heat flux exchanged at the wall and the mean Nusselt number are calculated using several closure models in the liquid and vapor phases. Calculation results obtained for the R123 condensation between two vertical plates show that the Pletcher`s model or the Groenwald and Kroeger`s one applied to the vapor flow and the Von Karman`s model used for the liquid film predict thermal fluxes close to the measured ones. It has been noticed also that the condensation heat transfer is underestimated in the laminar model. In the case of the R113 condensation on an horizontal flat plate, the mean Nusselt numbers estimated in the Pletcher`s model applied to both phases are close to the measurements performed by Lu and Suryanarayana. (J.S.) 12 refs.

Condensation of nano-refrigerant inside a horizontal tube

Science.gov (United States)

Darzi, Milad; Sadoughi, M. K.; Sheikholeslami, M.

2018-05-01

In this paper, condensing pressure drop of refrigerant-based nanofluid inside a tube is studied. Isobutene was selected as the base fluid while CuO nanoparticles were utilized to prepare nano-refrigerant. However, for the feasibility of nanoparticle dispersion into the refrigerant, Polyester oil (POE) was utilized as lubricant oil and added to the pure refrigerant by 1% mass fraction. Various values of mass flux, vapor quality, concentration of nanoparticle are investigated. Results indicate that adding nanoparticles leads to enhance frictional pressure drop. Nanoparticles caused larger pressure drop penalty at relatively lower vapor qualities which may be attributed to the existing condensation flow pattern such that annular flow is less influenced by nanoparticles compared to intermittent flow regime.

Pion condensation in cold dense matter and neutron stars

International Nuclear Information System (INIS)

Haensel, P.; Proszynski, M.

1982-01-01

We study possible influence, on the neutron star structure, of a pion condensation occurring in cold dense matter. Several equations of state with pion-condensed phase are considered. The models of neutron stars are calculated and confronted with existing observational data on pulsars. Such a confrontation appears to rule out the models of dense matter with an abnormal self-bound state, and therefore it seems to exclude the possibility of the existence of abnormal superheavy neutron nuclei and abnormal neutron stars with a liquid pion-condensed surface

NUCLEAR CONDENSATE AND HELIUM WHITE DWARFS

Energy Technology Data Exchange (ETDEWEB)

Bedaque, Paulo F.; Berkowitz, Evan [Maryland Center for Fundamental Physics, Department of Physics, University of Maryland, College Park, MD (United States); Cherman, Aleksey, E-mail: bedaque@umd.edu, E-mail: evanb@umd.edu, E-mail: a.cherman@damtp.cam.ac.uk [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA (United Kingdom)

2012-04-10

We consider a high-density region of the helium phase diagram, where the nuclei form a Bose-Einstein condensate rather than a classical plasma or a crystal. Helium in this phase may be present in helium-core white dwarfs. We show that in this regime there is a new gapless quasiparticle not previously noticed, arising when the constraints imposed by gauge symmetry are taken into account. The contribution of this quasiparticle to the specific heat of a white dwarf core turns out to be comparable in a range of temperatures to the contribution from the particle-hole excitations of the degenerate electrons. The specific heat in the condensed phase is two orders of magnitude smaller than in the uncondensed plasma phase, which is the ground state at higher temperatures, and four orders of magnitude smaller than the specific heat that an ion lattice would provide, if formed. Since the specific heat of the core is an important input for setting the rate of cooling of a white dwarf star, it may turn out that such a change in the thermal properties of the cores of helium white dwarfs has observable implications.

NUCLEAR CONDENSATE AND HELIUM WHITE DWARFS

International Nuclear Information System (INIS)

Bedaque, Paulo F.; Berkowitz, Evan; Cherman, Aleksey

2012-01-01

We consider a high-density region of the helium phase diagram, where the nuclei form a Bose-Einstein condensate rather than a classical plasma or a crystal. Helium in this phase may be present in helium-core white dwarfs. We show that in this regime there is a new gapless quasiparticle not previously noticed, arising when the constraints imposed by gauge symmetry are taken into account. The contribution of this quasiparticle to the specific heat of a white dwarf core turns out to be comparable in a range of temperatures to the contribution from the particle-hole excitations of the degenerate electrons. The specific heat in the condensed phase is two orders of magnitude smaller than in the uncondensed plasma phase, which is the ground state at higher temperatures, and four orders of magnitude smaller than the specific heat that an ion lattice would provide, if formed. Since the specific heat of the core is an important input for setting the rate of cooling of a white dwarf star, it may turn out that such a change in the thermal properties of the cores of helium white dwarfs has observable implications.

Interconversion of pollutants from the gaseous to the condensed phase. Technical progress report - brief summary of recent findings, March 1, 1983-August 31, 1983

International Nuclear Information System (INIS)

1983-01-01

Purpose of the studies were to provide new information on the interconversion of pollutants from the gaseous to the condensed phase. More information were obtained on mechanisms of cluster formation, leading to the production of prenucleation embryos, rates of phase transformation, and the thermochemical properties and photochemical stability of the species involved. Systems studied included nitric acid, ammonia, sulfuric acid, carbonic acid, etc

interThermalPhaseChangeFoam—A framework for two-phase flow simulations with thermally driven phase change

Directory of Open Access Journals (Sweden)

Mahdi Nabil

2016-01-01

Full Text Available The volume-of-fluid (VOF approach is a mature technique for simulating two-phase flows. However, VOF simulation of phase-change heat transfer is still in its infancy. Multiple closure formulations have been proposed in the literature, each suited to different applications. While these have enabled significant research advances, few implementations are publicly available, actively maintained, or inter-operable. Here, a VOF solver is presented (interThermalPhaseChangeFoam, which incorporates an extensible framework for phase-change heat transfer modeling, enabling simulation of diverse phenomena in a single environment. The solver employs object oriented OpenFOAM library features, including Run-Time-Type-Identification to enable rapid implementation and run-time selection of phase change and surface tension force models. The solver is packaged with multiple phase change and surface tension closure models, adapted and refined from earlier studies. This code has previously been applied to study wavy film condensation, Taylor flow evaporation, nucleate boiling, and dropwise condensation. Tutorial cases are provided for simulation of horizontal film condensation, smooth and wavy falling film condensation, nucleate boiling, and bubble condensation. Validation and grid sensitivity studies, interfacial transport models, effects of spurious currents from surface tension models, effects of artificial heat transfer due to numerical factors, and parallel scaling performance are described in detail in the Supplemental Material (see Appendix A. By incorporating the framework and demonstration cases into a single environment, users can rapidly apply the solver to study phase-change processes of interest.

interThermalPhaseChangeFoam-A framework for two-phase flow simulations with thermally driven phase change

Science.gov (United States)

Nabil, Mahdi; Rattner, Alexander S.

The volume-of-fluid (VOF) approach is a mature technique for simulating two-phase flows. However, VOF simulation of phase-change heat transfer is still in its infancy. Multiple closure formulations have been proposed in the literature, each suited to different applications. While these have enabled significant research advances, few implementations are publicly available, actively maintained, or inter-operable. Here, a VOF solver is presented (interThermalPhaseChangeFoam), which incorporates an extensible framework for phase-change heat transfer modeling, enabling simulation of diverse phenomena in a single environment. The solver employs object oriented OpenFOAM library features, including Run-Time-Type-Identification to enable rapid implementation and run-time selection of phase change and surface tension force models. The solver is packaged with multiple phase change and surface tension closure models, adapted and refined from earlier studies. This code has previously been applied to study wavy film condensation, Taylor flow evaporation, nucleate boiling, and dropwise condensation. Tutorial cases are provided for simulation of horizontal film condensation, smooth and wavy falling film condensation, nucleate boiling, and bubble condensation. Validation and grid sensitivity studies, interfacial transport models, effects of spurious currents from surface tension models, effects of artificial heat transfer due to numerical factors, and parallel scaling performance are described in detail in the Supplemental Material (see Appendix A). By incorporating the framework and demonstration cases into a single environment, users can rapidly apply the solver to study phase-change processes of interest.

Linking the gaseous and the condensed phases of matter: The slow electron and its interactions

International Nuclear Information System (INIS)

Christophorou, L.G.

1993-01-01

The interfacing of the gaseous and the condensed phases of matter as effected by interphase and cluster studies on the behavior of key reactions involving slow electrons either as reacting initial particles or as products of the reactions themselves is discussed. Emphasis is placed on the measurement of both the cross sections and the energetics involved, although most of the available information to date is on the latter. The discussion is selectively focussed on electron scattering (especially the role of negative ion states in gases, clusters, and dense matter), ionization, electron attachment and photodetachment. The dominant role of the electric polarization of the medium is emphasized

Condensation in a Square Minichannel: Application of the VOF Method

CERN Document Server

Bortolin, V; Del Col, Davide

2014-01-01

A number of steady-state numerical simulations of condensation of R134a at mass fluxes of 400 kg m−2 s−1 and 800 kg m−2 s−1 inside a 1-mm square cross section minichannel are proposed here and compared against simulations in a circular cross section channel with the same hydraulic diameter. The volume of fluid (VOF) method is used to track the vapor–liquid interface, and the effects of interfacial shear stress, surface tension, and gravity are taken into account. A uniform wall temperature is fixed as a boundary condition. At both mass velocities the liquid film and the vapor core are treated as turbulent; a low-Re form of the SST k-ω model has been used for the modeling of turbulence through both the liquid and vapor phases. Numerical simulations are validated against experimental data. The influence of the surface tension on the shape of the vapor–liquid interface may provide some heat transfer enhancement in a square cross section minichannel, but this depends on the mass flux and it may be no...

Excitonic condensation for the surface states of topological insulator bilayers

International Nuclear Information System (INIS)

Wang Zhigang; Fu Zhenguo; Zhang Ping; Hao Ningning

2012-01-01

We propose a generic topological insulator bilayer (TIB) system to study the excitonic condensation with self-consistent mean-field (SCMF) theory. We show that the TIB system presents the crossover behavior from the Bardeen-Cooper-Schrieffer (BCS) limit to the Bose-Einstein condensation (BEC) limit. Moreover, in comparison with traditional semiconductor systems, we find that for the present system the superfluid property in the BEC phase is more sensitive to electron-hole density imbalance and the BCS phase is more robust. Applying this TIB model to the Bi 2 Se 3 -family material, we find that the BEC phase is most likely to be observed in experiment. We also calculate the critical temperature for the Bi 2 Se 3 -family TIB system, which is ∼100 K. More interestingly, one can expect this relative high-temperature excitonic condensation, since our calculated SCMF critical temperature is approximately equal to the Kosterlitz-Thouless transition temperature. (paper)

Steam condensation induced water hammer simulations for different pipelines

International Nuclear Information System (INIS)

Barna, I.F.; Ezsol, G.

2011-01-01

We investigate steam condensation induced water hammer (CIWH) phenomena and present theoretical results for different kind of pipelines. We analyze the process with the WAHA3 model based on two-phase flow six first-order partial differential equations that present one dimensional, surface averaged mass, momentum and energy balances. A second order accurate high-resolution shock-capturing numerical scheme was applied with different kind of limiters in the numerical calculations. At first, we present calculations for various pipelines in the VVER-440-312 type nuclear reactor. Our recent calculation clearly shows that the six conditions of Griffith are only necessary conditions for CIWH but not sufficient. As second results we performed calculations for various geometries and compare with the theory of Chun. (author)

Steam condensation on finned tubes, in the presence of non-condensable gases and aerosols: Influence of impaction, diffusiophoresis and settling on aerosol deposition

International Nuclear Information System (INIS)

Munoz-Cobo, J.L.; Pena, J.; Herranz, L.E.; Perez-Navarro, A.

2005-01-01

This paper presents a mechanistic model to predict the steam condensation on containment finned tube heat exchangers in the presence of non-condensable gases (NC) and aerosols. The total thermal resistance from the bulk gas to the coolant is formulated as a parallel combination of the convective and condensation gas resistances coupled in series to those of condensate layer, the aerosol fouling layer, the wall, and the coolant. The condensate layer thermal resistance is calculated by means of an Adamek-based condensation model. The aerosol fouling layer is computed based on diffusiophoresis, settling and impaction mechanisms. The gas mixture (steam plus NC) thermal resistance is formulated based on a diffusion layer modeling. Finally, this paper presents a Montecarlo method implemented in the FORTRAN code TAEROSOL that is able to compute the amount of aerosol mass that is deposited by impaction on the top of the finned tubes. The model results are compared with the available experimental data of the CONGA European project

Interplay between kaon condensation and hyperons in highly dense matter

International Nuclear Information System (INIS)

Muto, Takumi

2008-01-01

The possible coexistence and/or competition of kaon condensation with hyperons are investigated in hyperonic matter, where hyperons are mixed in the ground state of neutron-star matter. The formulation is based on the effective chiral Lagrangian for the kaon-baryon interaction and the nonrelativistic baryon-baryon interaction model. First, the onset condition of the s-wave kaon condensation realized from hyperonic matter is reexamined. It is shown that the usual assumption of the continuous phase transition is not always kept valid in the presence of the negatively charged hyperons (Σ - ). Second, the equation of state (EOS) of the kaon-condensed phase in hyperonic matter is discussed. In the case of the stronger kaon-baryon attractive interaction, it is shown that a local energy minimum with respect to the baryon number density appears as a result of considerable softening of the EOS due to both kaon condensation and hyperon mixing and recovering of the stiffness of the EOS at very high densities. This result implies a possible existence of self-bound objects with kaon condensates on any scale from an atomic nucleus to a neutron star

Time-of-flight expansion of binary Bose–Einstein condensates at finite temperature

Science.gov (United States)

Lee, K. L.; Jørgensen, N. B.; Wacker, L. J.; Skou, M. G.; Skalmstang, K. T.; Arlt, J. J.; Proukakis, N. P.

2018-05-01

Ultracold quantum gases provide a unique setting for studying and understanding the properties of interacting quantum systems. Here, we investigate a multi-component system of 87Rb–39K Bose–Einstein condensates (BECs) with tunable interactions both theoretically and experimentally. Such multi-component systems can be characterized by their miscibility, where miscible components lead to a mixed ground state and immiscible components form a phase-separated state. Here we perform the first full simulation of the dynamical expansion of this system including both BECs and thermal clouds, which allows for a detailed comparison with experimental results. In particular we show that striking features emerge in time-of-flight (TOF) for BECs with strong interspecies repulsion, even for systems which were separated in situ by a large gravitational sag. An analysis of the centre of mass positions of the BECs after expansion yields qualitative agreement with the homogeneous criterion for phase-separation, but reveals no clear transition point between the mixed and the separated phases. Instead one can identify a transition region, for which the presence of a gravitational sag is found to be advantageous. Moreover, we analyse the situation where only one component is condensed and show that the density distribution of the thermal component also shows some distinct features. Our work sheds new light on the analysis of multi-component systems after TOF and will guide future experiments on the detection of miscibility in these systems.

Interaction of a Bose–Einstein condensate and a superconductor via eddy currents

International Nuclear Information System (INIS)

Sapina, Igor; Dahm, Thomas

2013-01-01

We study center-of-mass oscillations of a dipolar Bose–Einstein condensate in the vicinity of a superconducting surface. We show that the magnetic field of the magnetic dipoles induces eddy currents in the superconductor, which act back on the Bose–Einstein condensate. This leads to a shift of its oscillation frequency and to an anharmonic coupling of the Bose–Einstein condensate with the superconductor. The anharmonicity creates a coupling to one of the collective modes of the condensate that can be resonantly enhanced if the parameters of the condensate are chosen properly. This provides a new physical mechanism to couple a Bose–Einstein condensate and a superconductor, which becomes significant for 52 Cr, 168 Er or 164 Dy condensates in superconducting microtraps. (paper)

Recondensation phenomena of a hot two-phase fluid in the presence of non condensable gases

International Nuclear Information System (INIS)

Berthoud, G.

1983-09-01

The condensation rates obtained during the expansion of a large hot bubble containing non condensable gases in its cold liquid is studied. The failure of theories derived from the Nusselt model for liquid metals led to use the kinetic theory of condensation. The additionnal resistance due to the presence of non condensable gases is expressed by the vapor diffusion through the layer of gases which accumulates at the interface. This model is then used to interprete experiments [fr

An experimental and numerical study into turbulent condensing steam jets in air

Energy Technology Data Exchange (ETDEWEB)

Oerlemans, S. [Faculty of Applied Physics Eindhoven, Univ. of Technology Eindhoven (Netherlands); Badie, R. [Philips Research Laboratories Eindhoven (Netherlands); Dongen, M.E.H. van [Faculty of Applied Physics, Eindhoven Univ. of Technology (Netherlands)

2001-07-01

Temperatures, velocities, and droplet sizes are measured in turbulent condensing steam jets produced by a facial sauna, for varying nozzle diameters and varying initial velocities (Re=3,600-9,200). The release of latent heat due to droplet condensation causes the temperature in the two-phase jet to be significantly higher than in a single-phase jet. At some distance from the nozzle, droplets reach a maximum size and start to evaporate again, which results in a change in sign of latent heat release. The distance of maximum size is determined from droplet size measurements. The experimental results are compared with semi-analytical expressions and with a fully coupled numerical model of the turbulent condensing steam jet. The increase in centreline temperature due to droplet condensation is successfully predicted. (orig.)

Bose–Einstein condensation in the Rindler space

Directory of Open Access Journals (Sweden)

Shingo Takeuchi

2015-11-01

Full Text Available Based on the Unruh effect, we calculate the critical acceleration of the Bose–Einstein condensation in a free complex scalar field at finite density in the Rindler space. Our model corresponds to an ideal gas performing constantly accelerating motion in a Minkowski space–time at zero-temperature, where the gas is composed of the complex scalar particles and it can be thought to be in a thermal-bath with the Unruh temperature. In the accelerating frame, the model will be in the Bose–Einstein condensation state at low acceleration; on the other hand, there will be no condensation at high acceleration by the thermal excitation brought into by the Unruh effect. Our critical acceleration is the one at which the Bose–Einstein condensation begins to appear in the accelerating frame when we decrease the acceleration gradually. To carry out the calculation, we assume that the critical acceleration is much larger than the mass of the particle.

The Effects of a Macromolecular Charring Agent with Gas Phase and Condense Phase Synergistic Flame Retardant Capability on the Properties of PP/IFR Composites

Science.gov (United States)

Chen, Hongda; Wang, Jihui; Ding, Anxin; Han, Xia; Sun, Ziheng

2018-01-01

In order to improve the efficiency of intumescent flame retardants (IFRs), a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine) (PETAT) with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP) in combination with ammonium polyphosphate (APP) via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR), and 1H nuclear magnetic resonance (NMR) spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) and thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR). The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI) values before and after soaking, underwritten laboratory-94 (UL-94) vertical burning test, cone calorimetric test (CCT), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS), and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR), total heat release (THR), and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame

The Effects of a Macromolecular Charring Agent with Gas Phase and Condense Phase Synergistic Flame Retardant Capability on the Properties of PP/IFR Composites

Directory of Open Access Journals (Sweden)

Hongda Chen

2018-01-01

Full Text Available In order to improve the efficiency of intumescent flame retardants (IFRs, a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine (PETAT with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP in combination with ammonium polyphosphate (APP via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR, and 1H nuclear magnetic resonance (NMR spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG and thermogravimetry–Fourier transform infrared spectroscopy (TG-FTIR. The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI values before and after soaking, underwritten laboratory-94 (UL-94 vertical burning test, cone calorimetric test (CCT, scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS, and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR, total heat release (THR, and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame

The Effects of a Macromolecular Charring Agent with Gas Phase and Condense Phase Synergistic Flame Retardant Capability on the Properties of PP/IFR Composites.

Science.gov (United States)

Chen, Hongda; Wang, Jihui; Ni, Aiqing; Ding, Anxin; Han, Xia; Sun, Ziheng

2018-01-11

In order to improve the efficiency of intumescent flame retardants (IFRs), a novel macromolecular charring agent named poly(ethanediamine-1,3,5-triazine-p-4-amino-2,2,6,6-tetramethylpiperidine) (PETAT) with gas phase and condense phase synergistic flame-retardant capability was synthesized and subsequently dispersed into polypropylene (PP) in combination with ammonium polyphosphate (APP) via a melt blending method. The chemical structure of PETAT was investigated by Fourier transform infrared spectroscopy (FTIR), and ¹H nuclear magnetic resonance (NMR) spectroscopy. Thermal properties of the PETAT and IFR systems were tested by thermogravimetric-derivative thermogravimetric analysis (TGA-DTG) and thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR). The mechanical properties, thermal stability, flame-retardant properties, water resistance, and structures of char residue in flame-retardant composites were characterized using tensile and flexural strength property tests, TGA, limiting oxygen index (LOI) values before and after soaking, underwritten laboratory-94 (UL-94) vertical burning test, cone calorimetric test (CCT), scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDXS), and FTIR. The results indicated that PETAT was successfully synthesized, and when the ratio of APP to PETAT was 2:1 with 25 wt % loading, the novel IFR system could reduce the deterioration of tensile strength and enhance the flexural strength of composites. Meanwhile, the flame-retardant composite was able to pass the UL-94 V-0 rating with an LOI value of 30.3%, and the peak of heat release rate (PHRR), total heat release (THR), and material fire hazard values were considerably decreased compared with others. In addition, composites also exhibited excellent water resistance properties compared with traditional IFR composites. SEM-EDXS and FTIR analyses of the char residues, as well as TG-FTIR analyses of IFR were used to investigate the flame

Chromosome condensation and radiation-induced G2 arrest studied by the induction of premature chromosome condensation following cell fusion

International Nuclear Information System (INIS)

Mitchell, J.B.; Bedford, J.S.

1978-01-01

When mitotic and interphase cells are fused together, the chromosomes of the interphase cell sometimes condense prematurely. The phenomenon of premature chromosome condensation (PCC) was utilized in investigating the problem of whether the chromosomes of cells suffering a radiation-induced G 2 delay are capable of condensation. Colcemide-arrested mitotic cells were fused with synchronized G 2 cells, and with irradiated cells suffering a G 2 delay. The frequency of PCC in mitotic X G 2 binucleate cells was determined. This was compared to the PCC frequency in an unirradiated synchronized population rich in G 2 cells after fusion with mitotic cells. Flash-labelling with 3 HTdR and autoradiography allowed S-phase cells to be eliminated. The frequency of G 2 PCCs was not significantly different for the irradiated G 2 -delayed or unirradiated cells. From these results it was concluded that the chromosomes of cells suffering a G 2 arrest are capable of condensation, although the involvement of the condensation process in radiation-induced G 2 delay could not be ruled out. (author)

Natural Occurrence of Aldol Condensation Products in Valencia Orange Oil.

Science.gov (United States)

Abreu, Ingo; Da Costa, Neil C; van Es, Alfred; Kim, Jung-A; Parasar, Uma; Poulsen, Mauricio L

2017-12-01

Cold pressed orange oils contain predominantly d-limonene (approximately 95%) and various other lower concentration monoterpenes, sesquiterpenes, sinensals plus 3 key aliphatic aldehydes: hexanal, octanal. and decanal. The aldol self-condensation products or "dimers" for each aldehyde have been postulated as being present at low concentrations in the oil. However, to date only the hexanal dimer has been previously reported. In this paper, cold pressed Valencia orange oil was fractionally distilled/folded and analyzed by GC and high resolution GC-MS to detect these compounds on 2 different capillary column phases. Subsequently the hexanal, octanal, and decanal self-aldol condensation products, 2-butyl-2-octenal, 2-hexyl-2-decenal, and 2-octyl-2-dodecenal, respectively, were detected in the folded oil. These predominantly trans configuration isomeric compounds were synthesized, to confirm them as being present in nature and evaluated organoleptically by a panel of evaluators. To further confirm the mechanism of their formation, the enriched oil was made into a simple beverage to show the effect on the formation of these aldol compounds under acidic conditions. Finally aliphatic aldehydes from hexanal to undecanal were reacted together in various combinatorial pairs to give an additional 33 self and mixed aldol condensation products, some of which were also detected in the folded oil. This paper discloses the structural elucidation and synthesis of 8 novel aldol condensation products found at trace concentrations in citrus and leading to a further 31 mass spectrally determined aldol products. Sensory evaluations and application of some of these components were demonstrated in a model citrus beverage. © 2017 Institute of Food Technologists®.

Galaxy formation-a condensation process just after recombination

International Nuclear Information System (INIS)

Lessner, G.

1998-01-01

A scenario of galaxy formation is put forward which is a process of sudden condensation just after recombination. It is essentially based on the fact that the cosmic-matter gas after recombination is a general relativistic Boltzmann gas which runs within a few 10 6 years into a tate very close to collision-dominated equilibrium. The mass spectrum of axially symmetric condensation 'drops' extends from the lower limit M ≅ 10 5 M to the upper limit M ≅ 10 12 M. The lower-limit masses are spheres whereas the upper-limit masses are thin pancakes. These pancakes contract within a time of about 2.5 · 10 9 y to rotating spiral galaxies with ordinary proportions. In this final state they have a redshift z ≅ 3. At an earlier time during their contraction they are highly active and are observed with a redshift z ≅ 5

Dispersion Engineering of Bose-Einstein Condensates

Science.gov (United States)

Khamehchi, Mohammad Amin

The subject of this dissertation is engineering the dispersion relation for dilute Bose-Einstein condensates (BECs). When a BEC is immersed into suitably tailored laser fields its dispersion can be strongly modified. Prominent examples for such laser fields include optical lattice geometries and Raman dressing fields. The ability to engineer the dispersion of a BEC allows for the investigation of a range of phenomena related to quantum hydrodynamics and condensed matter. In the first context, this dissertation studies the excitation spectrum of a spin-orbit coupled (SOC) BEC. The spin-orbit coupling is generated by " dressing" the atoms with two Raman laser fields. The excitation spectrum has a Roton-like feature that can be altered by tuning the Raman laser parameters. It is demonstrated that the Roton mode can be softened, but it does not reach the ground state energy for the experimental conditions we had. Furthermore, the expansion of SOC BECs in 1D is studied by relaxing the trap allowing the BEC to expand in the SOC direction. Contrary to the findings for optical lattices, it is observed that the condensate partially occupies quasimomentum states with negative effective mass, and therefore an abrupt deceleration is observed although the mean field force is along the direction of expansion. In condensed-matter systems, a periodic lattice structure often plays an important role. In this context, an alternative to the Raman dressing scheme can be realized by coupling the s- and p- bands of a static optical lattice via a weak moving lattice. The bands can be treated as pseudo-spin states. It is shown that similar to the dispersion relation of a Raman dressed SOC, the quasimomentum of the ground state is different from zero. Coherent coupling of the SOC dispersion minima can lead to the realization of the stripe phase even though it is not the thermodynamic ground state of the system. Along the lines of studying the hydrodynamics of BECs, three novel

Nucleation and condensation in the primitive solar nebula

International Nuclear Information System (INIS)

Cameron, A.G.W.; Fegley, M.B.

1982-01-01

It is pointed out that the primitive solar nebula may be modeled using the frictionally induced transport theory of Lynden-Bell and Pringle (1974) if the principal frictional mechanism within the nebula is turbulent viscosity. The present investigation is concerned with the construction of a model of a section of the primitive solar nebula as a basis for the study of nucleation and condensation processes within this section. The construction involves a relatively simple application of the Lynden-Bell and Pringle theory subject to steady mass flow conditions. The calculations which are conducted in connection with the investigation indicate that by the time the gas in the primitive solar nebula has become sufficiently supercooled to nucleate condensation centers, several different compounds, including the magnesium silicates forsterite and enstatite (MgSiO 3 ), will probably be able to condense on the growing condensation center

Temperature dependence of the coherence in polariton condensates

Science.gov (United States)

Rozas, E.; Martín, M. D.; Tejedor, C.; Viña, L.; Deligeorgis, G.; Hatzopoulos, Z.; Savvidis, P. G.

2018-02-01

We present a time-resolved experimental study of the temperature effect on the coherence of traveling polariton condensates. The simultaneous detection of their emission both in real and reciprocal space allows us to fully monitor the condensates' dynamics. We obtain fringes in reciprocal space as a result of the interference between polariton wave packets (WPs) traveling with the same speed. The periodicity of these fringes is inversely proportional to the spatial distance between the interfering WPs. In a similar fashion, we obtain interference fringes in real space when WPs traveling in opposite directions meet. The visibility of both real- and reciprocal-space interference fringes rapidly decreases with increasing temperature and vanishes. A theoretical description of the phase transition, considering the coexistence of condensed and noncondensed particles, for an out-of-equilibrium condensate such as ours is still missing, yet a comparison with theories developed for atomic condensates allows us to infer a critical temperature for the BEC-like transition when the visibility goes to zero.

Ferroelectricity by Bose-Einstein condensation in a quantum magnet.

Science.gov (United States)

Kimura, S; Kakihata, K; Sawada, Y; Watanabe, K; Matsumoto, M; Hagiwara, M; Tanaka, H

2016-09-26

The Bose-Einstein condensation is a fascinating phenomenon, which results from quantum statistics for identical particles with an integer spin. Surprising properties, such as superfluidity, vortex quantization or Josephson effect, appear owing to the macroscopic quantum coherence, which spontaneously develops in Bose-Einstein condensates. Realization of Bose-Einstein condensation is not restricted in fluids like liquid helium, a superconducting phase of paired electrons in a metal and laser-cooled dilute alkali atoms. Bosonic quasi-particles like exciton-polariton and magnon in solids-state systems can also undergo Bose-Einstein condensation in certain conditions. Here, we report that the quantum coherence in Bose-Einstein condensate of the magnon quasi particles yields spontaneous electric polarization in the quantum magnet TlCuCl 3 , leading to remarkable magnetoelectric effect. Very soft ferroelectricity is realized as a consequence of the O(2) symmetry breaking by magnon Bose-Einstein condensation. The finding of this ferroelectricity will open a new window to explore multi-functionality of quantum magnets.

Field theoretic consistency of QCD operator product expansion contributions from chiral non-invariant condensates

International Nuclear Information System (INIS)

Elias, V.; Steele, T.G.

1987-01-01

Several field theoretic aspects of the operator product expansion (OPE) augmentation of QCD have been examined. Gauge independence of quark self-energies at the mass shell corresponding to the mass m (characterizing the OPE expansion parameter m/p) has been verified to all orders of the OPE for dimension 3 and 5 chiral symmetry breaking condensates. Similarly, the necessary transversality of the quark condensate contribution to the gluon self-energy has been verified, provided that propagator masses appearing in the self-energy are equilibrated with the OPE mass parameter m

Condensation of an ideal gas obeying non-Abelian statistics.

Science.gov (United States)

Mirza, Behrouz; Mohammadzadeh, Hosein

2011-09-01

We consider the thermodynamic geometry of an ideal non-Abelian gas. We show that, for a certain value of the fractional parameter and at the relevant maximum value of fugacity, the thermodynamic curvature has a singular point. This indicates a condensation such as Bose-Einstein condensation for non-Abelian statistics and we work out the phase transition temperature in various dimensions.

Two-fluid model with droplet size distribution for condensing steam flows

International Nuclear Information System (INIS)

Wróblewski, Włodzimierz; Dykas, Sławomir

2016-01-01

The process of energy conversion in the low pressure part of steam turbines may be improved using new and more accurate numerical models. The paper presents a description of a model intended for the condensing steam flow modelling. The model uses a standard condensation model. A physical and a numerical model of the mono- and polydispersed wet-steam flow are presented. The proposed two-fluid model solves separate flow governing equations for the compressible, inviscid vapour and liquid phase. The method of moments with a prescribed function is used for the reconstruction of the water droplet size distribution. The described model is presented for the liquid phase evolution in the flow through the de Laval nozzle. - Highlights: • Computational Fluid Dynamics. • Steam condensation in transonic flows through the Laval nozzles. • In-house CFD code – two-phase flow, two-fluid monodispersed and polydispersed model.

Dark matter as a Bose-Einstein Condensate: the relativistic non-minimally coupled case

International Nuclear Information System (INIS)

Bettoni, Dario; Colombo, Mattia; Liberati, Stefano

2014-01-01

Bose-Einstein Condensates have been recently proposed as dark matter candidates. In order to characterize the phenomenology associated to such models, we extend previous investigations by studying the general case of a relativistic BEC on a curved background including a non-minimal coupling to curvature. In particular, we discuss the possibility of a two phase cosmological evolution: a cold dark matter-like phase at the large scales/early times and a condensed phase inside dark matter halos. During the first phase dark matter is described by a minimally coupled weakly self-interacting scalar field, while in the second one dark matter condensates and, we shall argue, develops as a consequence the non-minimal coupling. Finally, we discuss how such non-minimal coupling could provide a new mechanism to address cold dark matter paradigm issues at galactic scales

Two-phase pressurized thermal shock investigations using a 3D two-fluid modeling of stratified flow with condensation

International Nuclear Information System (INIS)

Yao, W.; Coste, P.; Bestion, D.; Boucker, M.

2003-01-01

In this paper, a local 3D two-fluid model for a turbulent stratified flow with/without condensation, which can be used to predict two-phase pressurized thermal shock, is presented. A modified turbulent K- model is proposed with turbulence production induced by interfacial friction. A model of interfacial friction based on a interfacial sublayer concept and three interfacial heat transfer models, namely, a model based on the small eddies controlled surface renewal concept (HDM, Hughes and Duffey, 1991), a model based on the asymptotic behavior of the Eddy Viscosity (EVM), and a model based on the Interfacial Sublayer concept (ISM) are implemented into a preliminary version of the NEPTUNE code based on the 3D module of the CATHARE code. As a first step to apply the above models to predict the two-phase thermal shock, the models are evaluated by comparison of calculated profiles with several experiments: a turbulent air-water stratified flow without interfacial heat transfer; a turbulent steam-water stratified flow with condensation; turbulence induced by the impact of a water jet in a water pool. The prediction results agree well with the experimental data. In addition, the comparison of three interfacial heat transfer models shows that EVM and ISM gave better prediction results while HDM highly overestimated the interfacial heat transfers compared to the experimental data of a steam water stratified flow

Heavy quark condensates from dynamically borken flavour symmetry

International Nuclear Information System (INIS)

Elliott, T.; King, S.F.

1992-01-01

We study the dynamics of top quark condensation induced by gauge interactions resulting from a broken flavour symmetry. The gap equation in dressed ladder approximation is solved numerically to obtain directly the top quark mass. The new high energy dynamics reduces the prediction of m t somewhat, but the usual problems of m t being too large and fine tuning remain. In order to solve these problems we extend our discussion to include fourth generation quark condensates. (orig.)

Quantum Hall effect with small numbers of vortices in Bose-Einstein condensates

Science.gov (United States)

Byrnes, Tim; Dowling, Jonathan P.

2015-08-01

When vortices are displaced in Bose-Einstein condensates (BECs), the Magnus force gives the system a momentum transverse in the direction to the displacement. We show that BECs in long channels with vortices exhibit a quantization of the current response with respect to the spatial vortex distribution. The quantization originates from the well-known topological property of the phase around a vortex; it is an integer multiple of 2 π . In a way similar to that of the integer quantum Hall effect, the current along the channel is related to this topological phase and can be extracted from two experimentally measurable quantities: the total momentum of the BEC and the spatial distribution. The quantization is in units of m /2 h , where m is the mass of the atoms and h is Planck's constant. We derive an exact vortex momentum-displacement relation for BECs in long channels under general circumstances. Our results present the possibility that the configuration described here can be used as a novel way of measuring the mass of the atoms in the BEC using a topological invariant of the system. If an accurate determination of the plateaus are experimentally possible, this gives the possibility of a topological quantum mass standard and precise determination of the fine structure constant.

Physics through the 1990s: condensed-matter physics

International Nuclear Information System (INIS)

1986-01-01

The volume presents the current status of condensed-matter physics from developments since the 1970s to opportunities in the 1990s. Topics include electronic structure, vibrational properties, critical phenomena and phase transitions, magnetism, semiconductors, defects and diffusion, surfaces and interfaces, low-temperature physics, liquid-state physics, polymers, nonlinear dynamics, instabilities, and chaos. Appendices cover the connections between condensed-matter physics and applications of national interest, new experimental techniques and materials, laser spectroscopy, and national facilities for condensed-matter physics research. The needs of the research community regarding support for individual researchers and for national facilities are presented, as are recommendations for improved government-academic-industrial relations

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

Science.gov (United States)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2017-12-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

Science.gov (United States)

Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

2018-06-01

Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

Quark condensate contributions to the gluon self-energy and the ρ meson sum rule

International Nuclear Information System (INIS)

Steele, T.G.

1989-01-01

The operator-product expansion will be employed to obtain the lowest-order, quark condensate component of both the gluon self-energy and the ρ meson correlation function to all orders in the quark mass parameter. Field-theoretic aspects of the self-energy and correlation function will be considered, and physical effects to the quark condensate upon gluon mass generation will be examined. (orig.)

Ice condenser containment analysis with the GOTHIC code

International Nuclear Information System (INIS)

Yadon, T.P.

1996-01-01

Analytical methodologies have recently been developed by Duke Power Company (Duke) to calculate the thermodynamic response of the ice condenser containment buildings at the McGuire and Catawba Nuclear Stations to high-energy line breaks. The GOTHIC computer code (Version 4.0) was utilized for these analyses. In the ice condenser containment design, a large mass of ice stored within the containment building is used to absorb the energy released from high-energy line breaks, thereby limiting the peak pressure and temperature in the containment building to within design limits. The McGuire and Catawba Nuclear Stations (both two-unit, 3411 MWth four-loop Westinghouse plants) are of the ice condenser containment design

How to fix a broken symmetry: quantum dynamics of symmetry restoration in a ferromagnetic Bose-Einstein condensate

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

Sensitivity analysis and economic optimization studies of inverted five-spot gas cycling in gas condensate reservoir

OpenAIRE

Shams Bilal; Yao Jun; Zhang Kai; Zhang Lei

2017-01-01

Gas condensate reservoirs usually exhibit complex flow behaviors because of propagation response of pressure drop from the wellbore into the reservoir. When reservoir pressure drops below the dew point in two phase flow of gas and condensate, the accumulation of large condensate amount occurs in the gas condensate reservoirs. Usually, the saturation of condensate accumulation in volumetric gas condensate reservoirs is lower than the critical condensate saturation that causes trapping of large...

Modelling of the processes of heat and mass transfer in adiabatic steam and drop flows

International Nuclear Information System (INIS)

Andrizhievskij, A.A.; Mikhalevich, A.A.; Nesterenko, V.B.; Trifonov, A.G.

1983-01-01

The mathematical models for investigating the local and integral characteristics of heat and mass transfer processes during simultaneous motion of adiabatic steam and drop flow and a flux of impurity particles are given. The mathematical model is constrUcted on the basis of one-dimensional stationary eqUations of conservation of mass, thermal energy and momentum of liquid and vapor phases. Dispersion composition of condensed moisture is described by the Nukiyama-Tanasava distribution function formed taking into account the Veber number critical value. Equations of motion and mass balance conservation for impurity particles are included into the mathematical model. These equations are considered as additional inactive phase

Increased ionization supports growth of aerosols into cloud condensation nuclei

DEFF Research Database (Denmark)

Svensmark, H.; Enghoff, M. B.; Shaviv, N. J.

2017-01-01

Ions produced by cosmic rays have been thought to influence aerosols and clouds. In this study, the effect of ionization on the growth of aerosols into cloud condensation nuclei is investigated theoretically and experimentally. We show that the mass-flux of small ions can constitute an important...... and find good agreement with theory. Ion-induced condensation should be of importance not just in Earth’s present day atmosphere for the growth of aerosols into cloud condensation nuclei under pristine marine conditions, but also under elevated atmospheric ionization caused by increased supernova activity....

Condensation of Methane in the Metal-Organic Framework IRMOF-1: Evidence for Two Critical Points.

Science.gov (United States)

Höft, Nicolas; Horbach, Jürgen

2015-08-19

Extensive grand canonical Monte Carlo simulations in combination with successive umbrella sampling are used to investigate the condensation of methane in the nanoporous crystalline material IRMOF-1. Two different types of novel condensation transitions are found, each of them ending in a critical point: (i) a fluid-fluid transition at higher densities (the analog of the liquid-gas transition in the bulk) and (ii) a phase transition at low densities on the surface of the IRMOF-1 structure. The nature of these transitions is different from the usual capillary condensation in thin films and cylindrical pores where the coexisting phases are confined in one or two of the three spatial dimensions. In contrast to that, in IRMOF-1 the different phases can be described as bulk phases that are inhomogeneous due to the presence of the metal-organic framework. As a consequence, the condensation transitions in IRMOF-1 belong to the three-dimensional (3D) Ising universality class.

Study of condensation of refrigerants in a micro-channel for development of future compact micro-channel condensers

Science.gov (United States)

Chowdhury, Sourav

2009-12-01

Mini- and micro-channel technology has gained considerable ground in the recent years in industry and is favored due to its several advantages stemming from its high surface to volume ratio and high values of proof pressure it can withstand. Micro-channel technology has paved the way to development of highly compact heat exchangers with low cost and mass penalties. In the present work, the issues related to the sizing of compact micro-channel condensers have been explored. The considered designs encompass both the conventional and MEMS fabrication techniques. In case of MEMS-fabricated micro-channel condenser, wet etching of the micro-channel structures, followed by bonding of two such wafers with silicon nitride layers at the interface was attempted. It was concluded that the silicon nitride bonding requires great care in terms of high degree of surface flatness and absence of roughness and also high degree of surface purity and thus cannot be recommended for mass fabrication. Following this investigation, a carefully prepared experimental setup and test micro-channel with hydraulic diameter 700 mum and aspect ratio 7:1 was fabricated and overall heat transfer and pressure drop aspects of two condensing refrigerants, R134a and R245fa were studied at a variety of test conditions. To the best of author's knowledge, so far no data has been reported in the literature on condensation in such high aspect ratio micro-channels. Most of the published experimental works on condensation of refrigerants are concerning conventional hydraulic diameter channels (> 3mm) and only recently some experimental data has been reported in the sub-millimeter scale channels for which the surface tension and viscosity effects play a dominant role and the effect of gravity is diminished. It is found that both experimental data and empirically-derived correlations tend to under-predict the present data by an average of 25%. The reason for this deviation could be because a high aspect ratio

Enhancement of Condensation Heat Transfer Rate of the Air-Steam Mixture on a Passive Condenser System Using Annular Fins

Directory of Open Access Journals (Sweden)

Yeong-Jun Jang

2017-11-01

Full Text Available This paper presents an experimental investigation on the enhancement of the heat transfer rate of steam condensation on the external surfaces of a vertical tube with annular fins. A cylindrical condenser tube, which is 40 mm in outer diameter and 1000 mm in length, with annular disks of uniform cross-sectional area is fabricated in the manner of ensuring perfect contact between the base surface and fins. A total of 13 annular fins of 80 mm diameter were installed along the tube height in order to increase the effective heat transfer area by 85%. Through a series of condensation tests for the air-steam mixture under natural convection conditions, the heat transfer data was measured in the pressure range of between 2 and 5 bar, and the air mass fraction from 0.3 to 0.7. The rates of heat transfer of the finned tube are compared to those that are measured on a bare tube to demonstrate the enhanced performance by extended surfaces. In addition, based on the experimental results and the characteristics of steam condensation, the applicability of finned tubes to a large condenser system with a bundle layout is evaluated.

Colored condensates deep inside neutron stars

Directory of Open Access Journals (Sweden)

Blaschke David

2014-01-01

Full Text Available It is demonstrated how in the absence of solutions for QCD under conditions deep inside compact stars an equation of state can be obtained within a model that is built on the basic symmetries of the QCD Lagrangian, in particular chiral symmetry and color symmetry. While in the vacuum the chiral symmetry is spontaneously broken, it gets restored at high densities. Color symmetry, however, gets broken simultaneously by the formation of colorful diquark condensates. It is shown that a strong diquark condensate in cold dense quark matter is essential for supporting the possibility that such states could exist in the recently observed pulsars with masses of 2 Mʘ.

Artificial neural network analysis of a refrigeration system with an evaporative condenser

Energy Technology Data Exchange (ETDEWEB)

Ertunc, H.M. [Department of Mechatronics Engineering, Kocaeli University, 41040 Kocaeli (Turkey); Hosoz, M. [Department of Mechanical Education, Kocaeli University, 41380 Kocaeli (Turkey)

2006-04-01

This paper describes an application of artificial neural networks (ANNs) to predict the performance of a refrigeration system with an evaporative condenser. In order to gather data for training and testing the proposed ANN, an experimental refrigeration system with an evaporative condenser was set up. Then, steady-state test runs were conducted varying the evaporator load, air and water flow rates passing through the condenser and both dry and wet bulb temperatures of the air stream entering the condenser. Utilizing some of the experimental data, an ANN model for the system based on standard backpropagation algorithm was developed. The ANN was used for predicting various performance parameters of the system, namely the condenser heat rejection rate, refrigerant mass flow rate, compressor power, electric power input to the compressor motor and the coefficient of performance. The ANN predictions usually agree well with the experimental values with correlation coefficients in the range of 0.933-1.000, mean relative errors in the range of 1.90-4.18% and very low root mean square errors. Results show that refrigeration systems, even complex ones involving concurrent heat and mass transfer such as systems with an evaporative condenser, can alternatively be modelled using ANNs within a high degree of accuracy. [Author].

Improvements to TRAC models of condensing stratified flow. Pt. 1

International Nuclear Information System (INIS)

Zhang, Q.; Leslie, D.C.

1991-12-01

Direct contact condensation in stratified flow is an important phenomenon in LOCA analyses. In this report, the TRAC interfacial heat transfer model for stratified condensing flow has been assessed against the Bankoff experiments. A rectangular channel option has been added to the code to represent the experimental geometry. In almost all cases the TRAC heat transfer coefficient (HTC) over-predicts the condensation rates and in some cases it is so high that the predicted steam is sucked in from the normal outlet in order to conserve mass. Based on their cocurrent and countercurrent condensing flow experiments, Bankoff and his students (Lim 1981, Kim 1985) developed HTC models from the two cases. The replacement of the TRAC HTC with either of Bankoff's models greatly improves the predictions of condensation rates in the experiment with cocurrent condensing flow. However, the Bankoff HTC for countercurrent flow is preferable because it is based only on the local quantities rather than on the quantities averaged from the inlet. (author)

Experimental facility with two-phase flow and with high concentration of non-condensable gases for research and development of emergency cooling system of advanced nuclear reactors

International Nuclear Information System (INIS)

Macedo, Luiz Alberto; Baptista Filho, Benedito Dias

2006-01-01

The development of emergency cooling passive systems of advanced nuclear reactors requires the research of some relative processes to natural circulation, in two-phase flow conditions involving condensation processes in the presence of non-condensable gases. This work describes the main characteristics of the experimental facility called Bancada de Circulacao Natural (BCN), designed for natural circulation experiments in a system with a hot source, electric heater, a cold source, heat exchanger, operating with two-phase flow and with high concentration of noncondensable gas, air. The operational tests, the data acquisition system and the first experimental results in natural circulation are presented. The experiments are transitory in natural circulation considering power steps. The distribution of temperatures and the behavior of the flow and of the pressure are analyzed. The experimental facility, the instrumentation and the data acquisition system demonstrated to be adapted for the purposes of research of emergency cooling passive systems, operating with two-phase flow and with high concentration of noncondensable gases. (author)

Supersymmetry breaking by gaugino condensation

International Nuclear Information System (INIS)

Casas, J.A.

1991-01-01

We briefly review the status and some of the recent work on supersymmetry breaking by gaugino condensation effects in the context of superstring theories. This issue is intimately related to the structure of the effective potential coming from superstrings. Minimization of this not only allows to find the scale of supersymmetry breaking, but also to determine dynamically other fundamental parameters of the theory, in particular the gauge coupling constant at the unification point and the expectation values of the moduli which give the size and shape of the compactified space. In a multiple condensate scenario these get reasonable values which may, in turn, lead to a determination of the family mass hierarchy. Some directions for future work are examined too. (author). 23 refs

Phase separation of a Lennard-Jones fluid interacting with a long, condensed polymer chain: implications for the nuclear body formation near chromosomes.

Science.gov (United States)

Oh, Inrok; Choi, Saehyun; Jung, YounJoon; Kim, Jun Soo

2015-08-28

Phase separation in a biological cell nucleus occurs in a heterogeneous environment filled with a high density of chromatins and thus it is inevitably influenced by interactions with chromatins. As a model system of nuclear body formation in a cell nucleus filled with chromatins, we simulate the phase separation of a low-density Lennard-Jones (LJ) fluid interacting with a long, condensed polymer chain. The influence of the density variation of LJ particles above and below the phase boundary and the role of attractive interactions between LJ particles and polymer segments are investigated at a fixed value of strong self-interaction between LJ particles. For a density of LJ particles above the phase boundary, phase separation occurs and a dense domain of LJ particles forms irrespective of interactions with the condensed polymer chain whereas its localization relative to the polymer chain is determined by the LJ-polymer attraction strength. Especially, in the case of moderately weak attractions, the domain forms separately from the polymer chain and subsequently associates with the polymer chain. When the density is below the phase boundary, however, the formation of a dense domain is possible only when the LJ-polymer attraction is strong enough, for which the domain grows in direct contact with the interacting polymer chain. In this work, different growth behaviors of LJ particles result from the differences in the density of LJ particles and in the LJ-polymer interaction, and this work suggests that the distinct formation of activity-dependent and activity-independent nuclear bodies (NBs) in a cell nucleus may originate from the differences in the concentrations of body-specific NB components and in their interaction with chromatins.

Coherent magnon optics in a ferromagnetic spinor Bose-Einstein condensate.

Science.gov (United States)

Marti, G Edward; MacRae, Andrew; Olf, Ryan; Lourette, Sean; Fang, Fang; Stamper-Kurn, Dan M

2014-10-10

We measure the dispersion relation, gap, and magnetic moment of a magnon in the ferromagnetic F = 1 spinor Bose-Einstein condensate of (87)Rb. From the dispersion relation we measure an average effective mass 1.033(2)(stat)(10)(sys) times the atomic mass, as determined by interfering standing and running coherent magnon waves within the dense and trapped condensed gas. The measured mass is higher than theoretical predictions of mean-field and beyond-mean-field Beliaev theory for a bulk spinor Bose gas with s-wave contact interactions. We observe a magnon energy gap of h × 2.5(1)(stat)(2)(sys) Hz, which is consistent with the predicted effect of magnetic dipole-dipole interactions. These dipolar interactions may also account for the high magnon mass. The effective magnetic moment of -1.04(2)(stat)(8)(sys) times the atomic magnetic moment is consistent with mean-field theory.

Comparison of tubeside condensation and evaporation characteristics of smooth and enhanced heat transfer 1EHT tubes

International Nuclear Information System (INIS)

Kukulka, David J.; Smith, Rick; Li, Wei

2015-01-01

Results are presented here from an experimental investigation that was performed to evaluate the inside condensation and evaporation heat transfer of R410A, R22 and R32 that took place in a 12.7 mm (0.5 in) O.D. horizontal copper tube at low mass fluxes. Tubes considered in this evaluation consisted of a smooth tube (inner diameter 11.43 mm) and a newly developed enhanced surface Vipertex™ 1EHT tube. Heat transfer enhancement is an important factor in obtaining energy efficiency improvements in a variety of heat transfer applications. Utilization of enhanced heat transfer tubes is often utilized in the development of high performance air conditioning and refrigeration systems. Vipertex™ has designed and produced these surfaces through three dimensional material surface modifications which produces flow optimized, enhanced heat transfer tubes that increase heat transfer. Heat transfer enhancement plays an important role in improving energy efficiencies and developing high performance thermal systems. This study details the evaluation of the in-tube evaporation and condensation that takes place in these tubes over a wide range of conditions. The test apparatus utilized included a straight horizontal test section with an active length heated by water circulated in the surrounding annulus. Constant heat flux was maintained and refrigerant quality varied. In-tube evaporation measurements of R22, R32 and R410A are reported for evaporation at 10 °C with mass flow rates in the range of 15–40 kg h"−"1. Single phase measurements are reported for mass flow rates from 15 kg h"−"1 to 80 kg h"−"1. Condensation tests were conducted at a saturation temperature of 47 °C, with an inlet quality of 0.8 and an outlet quality of 0.1. In a comparison to smooth tubes, the average heat transfer coefficients for the Vipertex 1EHT tube exceeded those of a smooth tube. Average evaporation and condensation heat transfer coefficients for R22, R32 and R410A in the 1EHT

On Localized Vapor Pressure Gradients Governing Condensation and Frost Phenomena.

Science.gov (United States)

Nath, Saurabh; Boreyko, Jonathan B

2016-08-23

Interdroplet vapor pressure gradients are the driving mechanism for several phase-change phenomena such as condensation dry zones, interdroplet ice bridging, dry zones around ice, and frost halos. Despite the fundamental nature of the underlying pressure gradients, the majority of studies on these emerging phenomena have been primarily empirical. Using classical nucleation theory and Becker-Döring embryo formation kinetics, here we calculate the pressure field for all possible modes of condensation and desublimation in order to gain fundamental insight into how pressure gradients govern the behavior of dry zones, condensation frosting, and frost halos. Our findings reveal that in a variety of phase-change systems the thermodynamically favorable mode of nucleation can switch between condensation and desublimation depending upon the temperature and wettability of the surface. The calculated pressure field is used to model the length of a dry zone around liquid or ice droplets over a broad parameter space. The long-standing question of whether the vapor pressure at the interface of growing frost is saturated or supersaturated is resolved by considering the kinetics of interdroplet ice bridging. Finally, on the basis of theoretical calculations, we propose that there exists a new mode of frost halo that is yet to be experimentally observed; a bimodal phase map is developed, demonstrating its dependence on the temperature and wettability of the underlying substrate. We hope that the model and predictions contained herein will assist future efforts to exploit localized vapor pressure gradients for the design of spatially controlled or antifrosting phase-change systems.

Continuous condensation in nanogrooves

Science.gov (United States)

Malijevský, Alexandr

2018-05-01

We consider condensation in a capillary groove of width L and depth D , formed by walls that are completely wet (contact angle θ =0 ), which is in a contact with a gas reservoir of the chemical potential μ . On a mesoscopic level, the condensation process can be described in terms of the midpoint height ℓ of a meniscus formed at the liquid-gas interface. For macroscopically deep grooves (D →∞ ), and in the presence of long-range (dispersion) forces, the condensation corresponds to a second-order phase transition, such that ℓ ˜(μcc-μ ) -1 /4 as μ →μcc - where μc c is the chemical potential pertinent to capillary condensation in a slit pore of width L . For finite values of D , the transition becomes rounded and the groove becomes filled with liquid at a chemical potential higher than μc c with a difference of the order of D-3. For sufficiently deep grooves, the meniscus growth initially follows the power law ℓ ˜(μcc-μ ) -1 /4 , but this behavior eventually crosses over to ℓ ˜D -(μ-μc c) -1 /3 above μc c, with a gap between the two regimes shown to be δ ¯μ ˜D-3 . Right at μ =μc c , when the groove is only partially filled with liquid, the height of the meniscus scales as ℓ*˜(D3L) 1 /4 . Moreover, the chemical potential (or pressure) at which the groove is half-filled with liquid exhibits a nonmonotonic dependence on D with a maximum at D ≈3 L /2 and coincides with μc c when L ≈D . Finally, we show that condensation in finite grooves can be mapped on the condensation in capillary slits formed by two asymmetric (competing) walls a distance D apart with potential strengths depending on L . All these predictions, based on mesoscopic arguments, are confirmed by fully microscopic Rosenfeld's density functional theory with a reasonable agreement down to surprisingly small values of both L and D .

Electronically excited and ionized states in condensed phase: Theory and applications

Science.gov (United States)

Sadybekov, Arman

Predictive modeling of chemical processes in silico is a goal of XXI century. While robust and accurate methods exist for ground-state properties, reliable methods for excited states are still lacking and require further development. Electronically exited states are formed by interactions of matter with light and are responsible for key processes in solar energy harvesting, vision, artificial sensors, and photovoltaic applications. The greatest challenge to overcome on our way to a quantitative description of light-induced processes is accurate inclusion of the effect of the environment on excited states. All above mentioned processes occur in solution or solid state. Yet, there are few methodologies to study excited states in condensed phase. Application of highly accurate and robust methods, such as equation-of-motion coupled-cluster theory EOM-CC, is limited by a high computational cost and scaling precluding full quantum mechanical treatment of the entire system. In this thesis we present successful application of the EOM-CC family of methods to studies of excited states in liquid phase and build hierarchy of models for inclusion of the solvent effects. In the first part of the thesis we show that a simple gasphase model is sufficient to quantitatively analyze excited states in liquid benzene, while the latter part emphasizes the importance of explicit treatment of the solvent molecules in the case of glycine in water solution. In chapter 2, we use a simple dimer model to describe exciton formation in liquid and solid benzene. We show that sampling of dimer structures extracted from the liquid benzene is sufficient to correctly predict exited-state properties of the liquid. Our calculations explain experimentally observed features, which helped to understand the mechanism of the excimer formation in liquid benzene. Furthermore, we shed light on the difference between dimer configurations in the first solvation shell of liquid benzene and in unit cell of solid

Structure of Nonlocal quark vacuum condensate in non-perturbative QCD vacuum

International Nuclear Information System (INIS)

Xiang Qianfei; Ma Weixing; Zhou Lijuan; Jiang Weizhou

2014-01-01

Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions A_f and B_f given usually by the solutions of the DSEs of quark propagator, is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions A_f and B_f are given by the parameterized quark propagator functions σ_v"f (p"2) and σ_s"f (p"2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation. (authors)

Magnetic flux penetration and destruction of pion condensates

Energy Technology Data Exchange (ETDEWEB)

Harrington, B J; Shepard, H K [New Hampshire Univ., Durham (USA). Dept. of Physics

1976-08-30

It is shown that an external magnetic field can destroy a pion condensate or lead to a vortex ground state similar to the mixed phase of a type II superconductor. Critical magnetic fields, determined for the ground state phases of the sigma model, are comparable to those which may be present in neutron stars.

CFD modelling of condensers for freeze-drying processes

Indian Academy of Sciences (India)

Freeze-drying; condenser; CFD simulation; mathematical modelling; ... it is used for the stabilization and storage of delicate, heat-sensitive materials .... The effect of the surface mass transfer has been included in the continuity equation and.

The modelling of wall condensation with noncondensable gases for the containment codes

Energy Technology Data Exchange (ETDEWEB)

Leduc, C.; Coste, P.; Barthel, V.; Deslandes, H. [Commissariat a l`Energi Atomique, Grenoble (France)

1995-09-01

This paper presents several approaches in the modelling of wall condensation in the presence of noncondensable gases for containment codes. The lumped-parameter modelling and the local modelling by 3-D codes are discussed. Containment analysis codes should be able to predict the spatial distributions of steam, air, and hydrogen as well as the efficiency of cooling by wall condensation in both natural convection and forced convection situations. 3-D calculations with a turbulent diffusion modelling are necessary since the diffusion controls the local condensation whereas the wall condensation may redistribute the air and hydrogen mass in the containment. A fine mesh modelling of film condensation in forced convection has been in the developed taking into account the influence of the suction velocity at the liquid-gas interface. It is associated with the 3-D model of the TRIO code for the gas mixture where a k-{xi} turbulence model is used. The predictions are compared to the Huhtiniemi`s experimental data. The modelling of condensation in natural convection or mixed convection is more complex. As no universal velocity and temperature profile exist for such boundary layers, a very fine nodalization is necessary. More simple models integrate equations over the boundary layer thickness, using the heat and mass transfer analogy. The model predictions are compared with a MIT experiment. For the containment compartments a two node model is proposed using the lumped parameter approach. Heat and mass transfer coefficients are tested on separate effect tests and containment experiments. The CATHARE code has been adapted to perform such calculations and shows a reasonable agreement with data.

Capillary Condensation with a Grain of Salt.

Science.gov (United States)

Yarom, Michal; Marmur, Abraham

2017-11-21

Capillary condensation (CC), namely, the formation from the vapor of a stable phase of drops below the saturation pressure, is a prevalent phenomenon. It may occur inside porous structures or between surfaces of particles. CC between surfaces, a liquid "bridge", is of particular practical interest because of its resulting adhesive force. To date, studies have focused on pure water condensation. However, nonvolatile materials, such as salts and surfactants, are prevalent in many environments. In the current study, the effect of these contaminants on CC is investigated from a thermodynamic point of view. This is done by computing the Gibbs energy of such systems and developing the modified Kelvin equation, based on the Kohler theory. The results demonstrate that nonvolatile solutes may have a number of major effects, including an increase in the critical radius and the stabilization of the newly formed phase.

Capillary Condensation of Liquid 4He in Aerogel on Cooling Through λ Point

International Nuclear Information System (INIS)

Miyashita, W.; Yoneyama, K.; Kato, H.; Nomura, R.; Okuda, Y.

2006-01-01

Capillary condensation of liquid 4He in silica aerogel with a 90% porosity was investigated visually. The initial condition of the experiment was such that liquid 4He was present in the sample cell but not in the aerogel. This situation was realized by introducing the liquid into the cell at a fast rate to avoid liquefaction in the aerogel. The free surface of the liquid rose up in the cell with filling and eventually reached the bottom of the aerogel. Then, the aerogel absorbed the liquid by capillary condensation. The height of the liquid in the aerogel rose with time t roughly as t1/2 in the normal fluid phase. This behavior was consistent with the Washburn model. When the system was cooled through the λ point during the condensation, the liquid height started to rise faster in the superfluid phase with a constant velocity of about 0.3 mm/sec. The dynamics of capillary condensation was strongly dependent on whether the liquid 4He was in the normal or the superfluid phase

The axion mass in modular invariant supergravity

International Nuclear Information System (INIS)

Butter, Daniel; Gaillard, Mary K.

2005-01-01

When supersymmetry is broken by condensates with a single condensing gauge group, there is a nonanomalous R-symmetry that prevents the universal axion from acquiring a mass. It has been argued that, in the context of supergravity, higher dimension operators will break this symmetry and may generate an axion mass too large to allow the identification of the universal axion with the QCD axion. We show that such contributions to the axion mass are highly suppressed in a class of models where the effective Lagrangian for gaugino and matter condensation respects modular invariance (T-duality)

Signatures of exciton condensation in a transition metal dichalcogenide

Science.gov (United States)

Kogar, Anshul; Rak, Melinda S.; Vig, Sean; Husain, Ali A.; Flicker, Felix; Joe, Young Il; Venema, Luc; MacDougall, Greg J.; Chiang, Tai C.; Fradkin, Eduardo; van Wezel, Jasper; Abbamonte, Peter

2017-12-01

Bose condensation has shaped our understanding of macroscopic quantum phenomena, having been realized in superconductors, atomic gases, and liquid helium. Excitons are bosons that have been predicted to condense into either a superfluid or an insulating electronic crystal. Using the recently developed technique of momentum-resolved electron energy-loss spectroscopy (M-EELS), we studied electronic collective modes in the transition metal dichalcogenide semimetal 1T-TiSe2. Near the phase-transition temperature (190 kelvin), the energy of the electronic mode fell to zero at nonzero momentum, indicating dynamical slowing of plasma fluctuations and crystallization of the valence electrons into an exciton condensate. Our study provides compelling evidence for exciton condensation in a three-dimensional solid and establishes M-EELS as a versatile technique sensitive to valence band excitations in quantum materials.

An analysis of some basic studies on the condensation in the presence of non-condensable along a plane plate

International Nuclear Information System (INIS)

Vernier, P.; Dalbe, M.

1984-01-01

Our study aims at facilitating the calculation of vapour condensation rate in the containment vessel of a PWR system in the event of a LOCA. Emphasis is placed on filmwise condensation because of its prime importance in such events. We have restricted ourselves to the steady-state regimes. The previous studies consider a laminar film, coupled with a vapour-air mixture laminar boundary layer, which are developed under the action of body and/or pressure forces. It has been show that, depending on the air mass fraction, the condensation rate reduces drastically as a result of the diffusion phenomena. Moreover the effects of the vapour superheating have been discussed. When film and/or boundary layer are turbulents, there is no satisfactory theory but only experimental correlations. Owing to the effect of suction (condensation), the correlations for the various transfers from the boundary layer must be corrected by some factors stemming from the ''film theory''. One should be able to treat the coupling between the turbulent film and the boundary layer by the integral method [fr

Molecular fossils in Cretaceous condensate from western India

Science.gov (United States)