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Sample records for single phase fluid

  1. Even distribution/dividing of single-phase fluids by symmetric bifurcation of flow channels

    International Nuclear Information System (INIS)

    Liu, Hong; Li, Peiwen

    2013-01-01

    Highlights: ► We addressed an issue of distributing a flow to a number of flow channels uniformly. ► The flow distribution is accomplished through bifurcation of channels. ► Some key parameters to the flow distribution uniformity have been identified. ► Flow uniformity was studied for several versions of flow distributor designs. ► A novel fluid packaging device of high efficiency was provided. -- Abstract: This study addresses a fundamental issue of distributing a single-phase fluid flow into a number of flow channels uniformly. A basic mechanism of flow distribution is accomplished through bifurcation of channels that symmetrically split one flow channel into two downstream channels. Applying the basic mechanism, cascades flow distributions are designed to split one flow into a large number of downstream flows uniformly. Some key parameters decisive to the flow distribution uniformity in such a system have been identified, and the flow distribution uniformity of air was studied for several versions of flow distributor designs using CFD analysis. The effect of the key parameters of the flow channel designs to the flow distribution uniformity was investigated. As an example of industrial application, a novel fluid packaging device of high efficiency was proposed and some CFD analysis results for the device were provided. The optimized flow distributor makes a very good uniform flow distribution which will significantly improve the efficiency of fluid packaging. The technology is expected to be of great significance to many industrial devices that require high uniformity of flow distribution

  2. Cryogenic Fluid Transfer Components Using Single Crystal Piezoelectric Actuators, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid transfer components using single crystal piezoelectric actuators are proposed to enable low thermal mass, minimal heat leak, low power consumption...

  3. Cryogenic Fluid Transfer Components Using Single Crystal Piezoelectric Actuators, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid transfer components using single crystal piezoelectric actuators are proposed to enable low thermal mass, minimal heat leak, low power consumption...

  4. An equivalent ground thermal test method for single-phase fluid loop space radiator

    Directory of Open Access Journals (Sweden)

    Xianwen Ning

    2015-02-01

    Full Text Available Thermal vacuum test is widely used for the ground validation of spacecraft thermal control system. However, the conduction and convection can be simulated in normal ground pressure environment completely. By the employment of pumped fluid loops’ thermal control technology on spacecraft, conduction and convection become the main heat transfer behavior between radiator and inside cabin. As long as the heat transfer behavior between radiator and outer space can be equivalently simulated in normal pressure, the thermal vacuum test can be substituted by the normal ground pressure thermal test. In this paper, an equivalent normal pressure thermal test method for the spacecraft single-phase fluid loop radiator is proposed. The heat radiation between radiator and outer space has been equivalently simulated by combination of a group of refrigerators and thermal electrical cooler (TEC array. By adjusting the heat rejection of each device, the relationship between heat flux and surface temperature of the radiator can be maintained. To verify this method, a validating system has been built up and the experiments have been carried out. The results indicate that the proposed equivalent ground thermal test method can simulate the heat rejection performance of radiator correctly and the temperature error between in-orbit theory value and experiment result of the radiator is less than 0.5 °C, except for the equipment startup period. This provides a potential method for the thermal test of space systems especially for extra-large spacecraft which employs single-phase fluid loop radiator as thermal control approach.

  5. Two-phase cooling fluids; Les fluides frigoporteurs diphasiques

    Energy Technology Data Exchange (ETDEWEB)

    Lallemand, A. [Institut National des Sciences Appliquees (INSA), 69 - Lyon (France)

    1997-12-31

    In the framework of the diminution of heat transfer fluid consumption, the concept of indirect refrigerating circuits, using cooling intermediate fluids, is reviewed and the fluids that are currently used in these systems are described. Two-phase cooling fluids advantages over single-phase fluids are presented with their thermophysical characteristics: solid fraction, two-phase mixture enthalpy, thermal and rheological properties, determination of heat and mass transfer characteristics, and cold storage through ice slurry

  6. Study of single- and two-phase fluid transfer between subchannels at Kumamoto University

    International Nuclear Information System (INIS)

    Sadatomi, Michio

    2004-01-01

    Firstly, the definitions of turbulent mixing, void drift and diversion cross-flow, which are three components of fluid transfer between subchannels, are given together with the relations of each component with equilibrium or non-equilibrium two-phase subchannel flows. Secondly, measuring techniques of the three components are briefly presented in turn together with typical measurement results. In turbulent mixing measurement, a tracer injection method has been adopted at Kumamoto University, while an isokinetic discharge method for both void drift an diversion cross-flow measurements. In the experiment of hydraulically non-equilibrium flow with both void drift and/or diversion cross-flow, experimental data on flow redistribution process have been obtained. The data include the axial variations of gas and liquid flow rates and void fraction in each subchannel and pressure difference between the subchannels. After analyzing these variations, some correlations on the void drift and the diversion cross-flow are obtained. Finally, a subchannel analysis code used at Kumamoto University is presented together with the results of its validation test against the experimental data on flow redistribution process mentioned above. The code is based on a two-phase two-fluid model, and is applicable to adiabatic two-phase flows under steady state condition. Basic equations in the code are the conservation equations of mass, axial momentum and lateral momentum, while the constitutive equations include the correlations of void diffusion coefficient, both interfacial and wall friction coefficients for the cross-flow, etc. (author)

  7. Design of Accumulators and Liquid/Gas Charging of Single Phase Mechanically Pumped Fluid Loop Heat Rejection Systems

    Science.gov (United States)

    Bhandari, Pradeep; Dudik, Brenda; Birur, Gajanana; Karlmann, Paul; Bame, David; Mastropietro, A. J.

    2012-01-01

    For single phase mechanically pumped fluid loops used for thermal control of spacecraft, a gas charged accumulator is typically used to modulate pressures within the loop. This is needed to accommodate changes in the working fluid volume due to changes in the operating temperatures as the spacecraft encounters varying thermal environments during its mission. Overall, the three key requirements on the accumulator to maintain an appropriate pressure range throughout the mission are: accommodation of the volume change of the fluid due to temperature changes, avoidance of pump cavitation and prevention of boiling in the liquid. The sizing and design of such an accumulator requires very careful and accurate accounting of temperature distribution within each element of the working fluid for the entire range of conditions expected, accurate knowledge of volume of each fluid element, assessment of corresponding pressures needed to avoid boiling in the liquid, as well as the pressures needed to avoid cavitation in the pump. The appropriate liquid and accumulator strokes required to accommodate the liquid volume change, as well as the appropriate gas volumes, require proper sizing to ensure that the correct pressure range is maintained during the mission. Additionally, a very careful assessment of the process for charging both the gas side and the liquid side of the accumulator is required to properly position the bellows and pressurize the system to a level commensurate with requirements. To achieve the accurate sizing of the accumulator and the charging of the system, sophisticated EXCEL based spreadsheets were developed to rapidly come up with an accumulator design and the corresponding charging parameters. These spreadsheets have proven to be computationally fast and accurate tools for this purpose. This paper will describe the entire process of designing and charging the system, using a case study of the Mars Science Laboratory (MSL) fluid loops, which is en route to

  8. Simulating single-phase and two-phase non-Newtonian fluid flow of a digital rock scanned at high resolution

    Science.gov (United States)

    Tembely, Moussa; Alsumaiti, Ali M.; Jouini, Mohamed S.; Rahimov, Khurshed; Dolatabadi, Ali

    2017-11-01

    Most of the digital rock physics (DRP) simulations focus on Newtonian fluids and overlook the detailed description of rock-fluid interaction. A better understanding of multiphase non-Newtonian fluid flow at pore-scale is crucial for optimizing enhanced oil recovery (EOR). The Darcy scale properties of reservoir rocks such as the capillary pressure curves and the relative permeability are controlled by the pore-scale behavior of the multiphase flow. In the present work, a volume of fluid (VOF) method coupled with an adaptive meshing technique is used to perform the pore-scale simulation on a 3D X-ray micro-tomography (CT) images of rock samples. The numerical model is based on the resolution of the Navier-Stokes equations along with a phase fraction equation incorporating the dynamics contact model. The simulations of a single phase flow for the absolute permeability showed a good agreement with the literature benchmark. Subsequently, the code is used to simulate a two-phase flow consisting of a polymer solution, displaying a shear-thinning power law viscosity. The simulations enable to access the impact of the consistency factor (K), the behavior index (n), along with the two contact angles (advancing and receding) on the relative permeability.

  9. Single-phase CFD applicability for estimating fluid hot-spot locations in a 5 x 5 fuel rod bundle

    International Nuclear Information System (INIS)

    Ikeda, Kazuo; Makino, Yasushi; Hoshi, Masaya

    2006-01-01

    High-thermal performance PWR spacer grids require both of low pressure loss and high critical heat flux (CHF) properties. Therefore, a numerical study using computational fluid dynamics (CFD) was carried out to estimate pressure loss in strap and mixing vane structures. Moreover, a CFD simulation under single-phase flow condition was conducted for one specific condition in a water departure from nucleate boiling (DNB) test to examine the applicability of the CFD model for predicting the CHF rod position. Energy flux around the rod surface in a water DNB test is the sum of the intrinsic energy flux from a rod and the extrinsic energy flux from other rods, and increments of the enthalpy and decrements of flow velocity near the rod surface are assumed to affect CHF performance. CFD makes it possible to model the complicated flow field consisting of a spacer grid and a rod bundle and evaluate the local velocity and enthalpy distribution around the rod surface, which are assumed to determine the initial conditions for the two-phase structure. The results of this study indicate that single-phase CFD can play a significant role in designing PWR spacer grids for improved CHF performance

  10. Fluid-elastic Instability of Helical Tubes Subjected to Single-Phase External Flow and Two-Phase Internal Flow

    International Nuclear Information System (INIS)

    Jong Chull Jo; Myung Jo Jhung; Woong Sik Kim; Hho Jung Kim

    2004-01-01

    This study investigates the fluid-elastic instability characteristics of steam generator helical type tubes in operating nuclear power plants. The thermal-hydraulic conditions of both tube side and shell side flow fields are predicted by a general purpose computational fluid dynamics code employing the finite volume element modeling. To get the natural frequency, corresponding mode shape and participation factor, modal analyses are performed for helical type tubes with various conditions. Investigated are the effects of the helix angle, the number of supports and the status of the inner fluid on the modal, and fluid-elastic instability characteristics of the tubes, which are expressed in terms of the natural frequency, corresponding mode shape, and stability ratio. (authors)

  11. General model of phospholipid bilayers in fluid phase within the single chain mean field theory

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yachong; Baulin, Vladimir A. [Departament d’Enginyeria Química, Universitat Rovira i Virgili, Av. dels Paisos Catalans 26, 43007 Tarragona (Spain); Pogodin, Sergey [Institute of Chemical Research of Catalonia, ICIQ, Av. Paisos Catalans 16, 43007 Tarragona (Spain)

    2014-05-07

    Coarse-grained model for saturated phospholipids: 1,2-didecanoyl-sn-glycero-3-phosphocholine (DCPC), 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and unsaturated phospholipids: 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), 1,2- dioleoyl-sn-glycero-3-phosphocholine (DOPC) is introduced within the single chain mean field theory. A single set of parameters adjusted for DMPC bilayers gives an adequate description of equilibrium and mechanical properties of a range of saturated lipid molecules that differ only in length of their hydrophobic tails and unsaturated (POPC, DOPC) phospholipids which have double bonds in the tails. A double bond is modeled with a fixed angle of 120°, while the rest of the parameters are kept the same as saturated lipids. The thickness of the bilayer and its hydrophobic core, the compressibility, and the equilibrium area per lipid correspond to experimentally measured values for each lipid, changing linearly with the length of the tail. The model for unsaturated phospholipids also fetches main thermodynamical properties of the bilayers. This model is used for an accurate estimation of the free energies of the compressed or stretched bilayers in stacks or multilayers and gives reasonable estimates for free energies. The proposed model may further be used for studies of mixtures of lipids, small molecule inclusions, interactions of bilayers with embedded proteins.

  12. A highly self-adaptive cold plate for the single-phase mechanically pumped fluid loop for spacecraft thermal management

    International Nuclear Information System (INIS)

    Wang, Ji-Xiang; Li, Yun-Ze; Zhang, Hong-Sheng; Wang, Sheng-Nan; Liang, Yi-Hao; Guo, Wei; Liu, Yang; Tian, Shao-Ping

    2016-01-01

    Highlights: • A highly self-adaptive cold plate integrated with paraffin-based actuator is proposed. • Higher operating economy is attained due to an energy-efficient strategy. • A greater compatibility of the current space control system is obtained. • Model was entrenched theoretically to design the system efficiently. • A strong self-adaptability of the cold plate is observed experimentally. - Abstract: Aiming to improve the conventional single-phase mechanically pumped fluid loop applied in spacecraft thermal control system, a novel actively-pumped loop using distributed thermal control strategy was proposed. The flow control system for each branch consists primarily of a thermal control valve integrated with a paraffin-based actuator residing in the front part of each corresponding cold plate, where both coolant’s flow rate and the cold plate’s heat removal capability are well controlled sensitively according to the heat loaded upon the cold plate due to a conversion between thermal and mechanical energies. The operating economy enhances remarkably owing to no energy consumption in flow control process. Additionally, realizing the integration of the sensor, controller and actuator systems, it simplifies structure of the traditional mechanically pumped fluid loop as well. Revolving this novel scheme, mathematical model regarding design process of the highly specialized cold plate was entrenched theoretically. A validating system as a prototype was established on the basis of the design method and the scheduled objective of the controlled temperature (43 °C). Then temperature control performances of the highly self-adaptive cold plate under various operating conditions were tested experimentally. During almost all experiments, the controlled temperature remains within a range of ±2 °C around the set-point. Conclusions can be drawn that this self-driven control system is stable with sufficient fast transient responses and sufficient small steady

  13. Phase-coexistence simulations of fluid mixtures by the Markov Chain Monte Carlo method using single-particle models

    KAUST Repository

    Li, Jun; Calo, Victor M.

    2013-01-01

    models although its deviation in the liquid phase is greater. Since the single-particle model reduces the particle number and avoids the time-consuming Ewald summation used to evaluate Coulomb interactions, the proposed model improves the computational

  14. Computational fluid dynamics simulations of single-phase flow in a filter-press flow reactor having a stack of three cells

    International Nuclear Information System (INIS)

    Sandoval, Miguel A.; Fuentes, Rosalba; Walsh, Frank C.; Nava, José L.; Ponce de León, Carlos

    2016-01-01

    Highlights: • Computational fluid dynamic simulations in a filter-press stack of three cells. • The fluid velocity was different in each cell due to local turbulence. • The upper cell link pipe of the filter press cell acts as a fluid mixer. • The fluid behaviour tends towards a continuous mixing flow pattern. • Close agreement between simulations and experimental data was achieved. - Abstract: Computational fluid dynamics (CFD) simulations were carried out for single-phase flow in a pre-pilot filter press flow reactor with a stack of three cells. Velocity profiles and streamlines were obtained by solving the Reynolds-Averaged Navier-Stokes (RANS) equations with a standard k − ε turbulence model. The flow behaviour shows the appearance of jet flow at the entrance to each cell. At lengths from 12 to 15 cm along the cells channels, a plug flow pattern is developed at all mean linear flow rates studied here, 1.2 ≤ u ≤ 2.1 cm s −1 . The magnitude of the velocity profiles in each cell was different, due to the turbulence generated by the change of flow direction in the last fluid manifold. Residence time distribution (RTD) simulations indicated that the fluid behaviour tends towards a continuous mixing flow pattern, owing to flow at the output of each cell across the upper cell link pipe, which acts as a mixer. Close agreement between simulations and experimental RTD was obtained.

  15. Phase-coexistence simulations of fluid mixtures by the Markov Chain Monte Carlo method using single-particle models

    KAUST Repository

    Li, Jun

    2013-09-01

    We present a single-particle Lennard-Jones (L-J) model for CO2 and N2. Simplified L-J models for other small polyatomic molecules can be obtained following the methodology described herein. The phase-coexistence diagrams of single-component systems computed using the proposed single-particle models for CO2 and N2 agree well with experimental data over a wide range of temperatures. These diagrams are computed using the Markov Chain Monte Carlo method based on the Gibbs-NVT ensemble. This good agreement validates the proposed simplified models. That is, with properly selected parameters, the single-particle models have similar accuracy in predicting gas-phase properties as more complex, state-of-the-art molecular models. To further test these single-particle models, three binary mixtures of CH4, CO2 and N2 are studied using a Gibbs-NPT ensemble. These results are compared against experimental data over a wide range of pressures. The single-particle model has similar accuracy in the gas phase as traditional models although its deviation in the liquid phase is greater. Since the single-particle model reduces the particle number and avoids the time-consuming Ewald summation used to evaluate Coulomb interactions, the proposed model improves the computational efficiency significantly, particularly in the case of high liquid density where the acceptance rate of the particle-swap trial move increases. We compare, at constant temperature and pressure, the Gibbs-NPT and Gibbs-NVT ensembles to analyze their performance differences and results consistency. As theoretically predicted, the agreement between the simulations implies that Gibbs-NVT can be used to validate Gibbs-NPT predictions when experimental data is not available. © 2013 Elsevier Inc.

  16. Phase space density representations in fluid dynamics

    International Nuclear Information System (INIS)

    Ramshaw, J.D.

    1989-01-01

    Phase space density representations of inviscid fluid dynamics were recently discussed by Abarbanel and Rouhi. Here it is shown that such representations may be simply derived and interpreted by means of the Liouville equation corresponding to the dynamical system of ordinary differential equations that describes fluid particle trajectories. The Hamiltonian and Poisson bracket for the phase space density then emerge as immediate consequences of the corresponding structure of the dynamics. For barotropic fluids, this approach leads by direct construction to the formulation presented by Abarbanel and Rouhi. Extensions of this formulation to inhomogeneous incompressible fluids and to fluids in which the state equation involves an additional transported scalar variable are constructed by augmenting the single-particle dynamics and phase space to include the relevant additional variable

  17. Fluid-flow pressure measurements and thermo-fluid characterization of a single loop two-phase passive heat transfer device

    Science.gov (United States)

    Ilinca, A.; Mangini, D.; Mameli, M.; Fioriti, D.; Filippeschi, S.; Araneo, L.; Roth, N.; Marengo, M.

    2017-11-01

    A Novel Single Loop Pulsating Heat Pipe (SLPHP), with an inner diameter of 2 mm, filled up with two working fluids (Ethanol and FC-72, Filling Ratio of 60%), is tested in Bottom Heated mode varying the heating power and the orientation. The static confinement diameter for Ethanol and FC-72, respectively 3.4 mm and 1.7mm, is above and slightly under the inner diameter of the tube. This is important for a better understanding of the working principle of the device very close to the limit between the Loop Thermosyphon and Pulsating Heat Pipe working modes. With respect to previous SLPHP experiments found in the literature, such device is designed with two transparent inserts mounted between the evaporator and the condenser allowing direct fluid flow visualization. Two highly accurate pressure transducers permit local pressure measurements just at the edges of one of the transparent inserts. Additionally, three heating elements are controlled independently, so as to vary the heating distribution at the evaporator. It is found that peculiar heating distributions promote the slug/plug flow motion in a preferential direction, increasing the device overall performance. Pressure measurements point out that the pressure drop between the evaporator and the condenser are related to the flow pattern. Furthermore, at high heat inputs, the flow regimes recorded for the two fluids are very similar, stressing that, when the dynamic effects start to play a major role in the system, the device classification between Loop Thermosyphon and Pulsating Heat Pipe is not that sharp anymore.

  18. Single-Phase PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2017-01-01

    Single-phase phase-locked loops (PLLs) are popular for the synchronization and control of single-phase gridconnected converters. They are also widely used for monitoring and diagnostic purposes in the power and energy areas. In recent years, a large number of single-phase PLLs with different stru......-PLLs). The members of each category are then described and their pros and cons are discussed. This work provides a deep insight into characteristics of different single-phase PLLs and, therefore, can be considered as a reference for researchers and engineers....

  19. A Finite-Volume approach for compressible single- and two-phase flows in flexible pipelines with fluid-structure interaction

    Science.gov (United States)

    Daude, F.; Galon, P.

    2018-06-01

    A Finite-Volume scheme for the numerical computations of compressible single- and two-phase flows in flexible pipelines is proposed based on an approximate Godunov-type approach. The spatial discretization is here obtained using the HLLC scheme. In addition, the numerical treatment of abrupt changes in area and network including several pipelines connected at junctions is also considered. The proposed approach is based on the integral form of the governing equations making it possible to tackle general equations of state. A coupled approach for the resolution of fluid-structure interaction of compressible fluid flowing in flexible pipes is considered. The structural problem is solved using Euler-Bernoulli beam finite elements. The present Finite-Volume method is applied to ideal gas and two-phase steam-water based on the Homogeneous Equilibrium Model (HEM) in conjunction with a tabulated equation of state in order to demonstrate its ability to tackle general equations of state. The extensive application of the scheme for both shock tube and other transient flow problems demonstrates its capability to resolve such problems accurately and robustly. Finally, the proposed 1-D fluid-structure interaction model appears to be computationally efficient.

  20. High-pressure fluid phase equilibria phenomenology and computation

    CERN Document Server

    Deiters, Ulrich K

    2012-01-01

    The book begins with an overview of the phase diagrams of fluid mixtures (fluid = liquid, gas, or supercritical state), which can show an astonishing variety when elevated pressures are taken into account; phenomena like retrograde condensation (single and double) and azeotropy (normal and double) are discussed. It then gives an introduction into the relevant thermodynamic equations for fluid mixtures, including some that are rarely found in modern textbooks, and shows how they can they be used to compute phase diagrams and related properties. This chapter gives a consistent and axiomatic approach to fluid thermodynamics; it avoids using activity coefficients. Further chapters are dedicated to solid-fluid phase equilibria and global phase diagrams (systematic search for phase diagram classes). The appendix contains numerical algorithms needed for the computations. The book thus enables the reader to create or improve computer programs for the calculation of fluid phase diagrams. introduces phase diagram class...

  1. A review of solid-fluid selection options for optical-based measurements in single-phase liquid, two-phase liquid-liquid and multiphase solid-liquid flows

    Science.gov (United States)

    Wright, Stuart F.; Zadrazil, Ivan; Markides, Christos N.

    2017-09-01

    Experimental techniques based on optical measurement principles have experienced significant growth in recent decades. They are able to provide detailed information with high-spatiotemporal resolution on important scalar (e.g., temperature, concentration, and phase) and vector (e.g., velocity) fields in single-phase or multiphase flows, as well as interfacial characteristics in the latter, which has been instrumental to step-changes in our fundamental understanding of these flows, and the development and validation of advanced models with ever-improving predictive accuracy and reliability. Relevant techniques rely upon well-established optical methods such as direct photography, laser-induced fluorescence, laser Doppler velocimetry/phase Doppler anemometry, particle image/tracking velocimetry, and variants thereof. The accuracy of the resulting data depends on numerous factors including, importantly, the refractive indices of the solids and liquids used. The best results are obtained when the observational materials have closely matched refractive indices, including test-section walls, liquid phases, and any suspended particles. This paper reviews solid-liquid and solid-liquid-liquid refractive-index-matched systems employed in different fields, e.g., multiphase flows, turbomachinery, bio-fluid flows, with an emphasis on liquid-liquid systems. The refractive indices of various aqueous and organic phases found in the literature span the range 1.330-1.620 and 1.251-1.637, respectively, allowing the identification of appropriate combinations to match selected transparent or translucent plastics/polymers, glasses, or custom materials in single-phase liquid or multiphase liquid-liquid flow systems. In addition, the refractive indices of fluids can be further tuned with the use of additives, which also allows for the matching of important flow similarity parameters such as density and viscosity.

  2. A novel application of Recursive Equation Method for determining thermodynamic properties of single phase fluids from density and speed-of-sound measurements

    International Nuclear Information System (INIS)

    Lago, S.; Giuliano Albo, P.A.

    2013-01-01

    Highlights: ► A novel method for calculating the isobaric specific heat capacity is presented. ► Heat capacity (C p ) was determined only by speed-of-sound and density measurements. ► (C p ) temperature dependence has been related to speed-of-sound by a new expression. ► Heat capacity for water, nonane, undecane, and rapeseed oil methyl ester are obtained. -- Abstract: The determination of thermal quantities from mechanical properties is still a challenge in the thermodynamic field. In this work, the authors suggest a preliminary numerical calculation which allows to determine the constant pressure specific heat capacity, starting from density and speed-of-sound experimental values, as input data. This method is a variant of the well characterized Recursive Equation Method (REM) [1] and permits to develop empirical equations of state for single phase fluids. In particular, the isobaric specific heat capacity has been obtained, in a wide range of temperatures and pressures, for pure water, n-nonane, n-undecane, and rapeseed oil methyl ester. The results have been compared with those available in the literature, when it was possible. Moreover, the typical uncertainty of heat capacity has been estimated to be in the order of 1.5%; however it has been shown that it can be improved when proper distributions of the experimental points are available

  3. Phase transitions of quadrupolar fluids

    International Nuclear Information System (INIS)

    OShea, S.F.; Dubey, G.S.; Rasaiah, J.C.

    1997-01-01

    Gibbs ensemble simulations are reported for Lennard-Jones particles with embedded quadrupoles of strength Q * =Q/(εσ 5 ) 1/2 =2.0 where ε and σ are the Lennard-Jones parameters. Calculations revealing the effect of the dispersive forces on the liquid endash vapor coexistence were carried out by scaling the attractive r -6 term in the Lennard-Jones pair potential by a factor λ ranging from 0 to 1. Liquid endash vapor coexistence is observed for all values of λ including λ=0 for Q * =2.0, unlike the corresponding dipolar fluid studied by van Leeuwen and Smit et al. [Phys. Rev. Lett. 71, 3991 (1993)] which showed no phase transition below λ=0.35 when the reduced dipole moment μ * =2.0. The simulation data are analyzed to estimate the critical properties of the quadrupolar fluid and their dependence on the strength λ of the dispersive force. The critical temperature and pressure show a clear quadratic dependence on λ, while the density is less confidently identified as being linear in λ. The compressibility is roughly linear in λ. copyright 1997 American Institute of Physics

  4. Single-particle Schroedinger fluid. I. Formulation

    International Nuclear Information System (INIS)

    Kan, K.K.; Griffin, J.J.

    1976-01-01

    The problem of a single quantal particle moving in a time-dependent external potential well is formulated specifically to emphasize and develop the fluid dynamical aspects of the matter flow. This idealized problem, the single-particle Schroedinger fluid, is shown to exhibit already a remarkably rich variety of fluid dynamical features, including compressible flow and line vortices. It provides also a sufficient framework to encompass simultaneously various simplified fluidic models for nuclei which have earlier been postulated on an ad hoc basis, and to illuminate their underlying restrictions. Explicit solutions of the single-particle Schroedinger fluid problem are studied in the adiabatic limit for their mathematical and physical implications (especially regarding the collective kinetic energy). The basic generalizations for extension of the treatment to the many-body Schroedinger fluid are set forth

  5. Thermodynamics phase changes of nanopore fluids

    KAUST Repository

    Islam, Akand W.; Patzek, Tadeusz; Sun, Alexander Y.

    2015-01-01

    The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.

  6. Thermodynamics phase changes of nanopore fluids

    KAUST Repository

    Islam, Akand W.

    2015-07-01

    The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.

  7. Phase equilibria in chemical reactive fluid mixtures

    International Nuclear Information System (INIS)

    Maurer, Gerd

    2011-01-01

    Downstream processing is a major part of nearly all processes in the chemical industries. Most separation processes in the chemical (and related) industries for fluid mixtures are based on phase equilibrium phenomena. The majority of separation processes can be modelled assuming that chemical reactions are of no (or very minor) importance, i.e., assuming that the overall speciation remains unchanged during a separation process. However, there are also a large number of industrially important processes where the thermodynamic properties are influenced by chemical reactions. The phase equilibrium of chemical reactive mixtures has been a major research area of the author's group over nearly 40 years. In this contribution, three examples from that research are discussed. The first example deals with the vapour phase dimerisation of carboxylic acids and its consequences on phase equilibrium phenomena and phase equilibrium predictions. The second example deals with the solubility of sour gases (e.g., carbon dioxide and sulfur dioxide) in aqueous solutions of ammonia. That topic has been of interest for many years, e.g., in relation with the gasification and liquefaction of coal and, more recently, with the removal of carbon dioxide from flue gas in the 'chilled ammonia process'. The third example deals with phase equilibrium phenomena in aqueous solutions of polyelectrolytes. It deals with the phenomenon of 'counter ion condensation' and methods to model the Gibbs free energy of such solutions.

  8. Phase coexistence properties of polarizable Stockmayer fluids

    International Nuclear Information System (INIS)

    Kiyohara, K.; Gubbins, K.E.; Panagiotopoulos, A.Z.

    1997-01-01

    We report the phase coexistence properties of polarizable Stockmayer fluids of reduced permanent dipoles |m 0 * |= 1.0 and 2.0 and reduced polarizabilities α * = 0.00, 0.03, and 0.06, calculated by a series of grand canonical Monte Carlo simulations with the histogram reweighting method. In the histogram reweighting method, the distributions of density and energy calculated in Grand Canonical Monte Carlo simulations are stored in histograms and analyzed to construct the grand canonical partition function of the system. All thermodynamic properties are calculated from the grand partition function. The results are compared with Wertheim close-quote s renormalization perturbation theory. Deviations between theory and simulation results for the coexistence envelope are near 2% for the lower dipole moment and 10% for the higher dipole moment we studied. copyright 1997 American Institute of Physics

  9. SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Pedro Samuel Gomes Medeiros

    2011-09-01

    Full Text Available This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids.

  10. Phase transitions of fluids in heterogeneous pores

    Directory of Open Access Journals (Sweden)

    A. Malijevský

    2016-03-01

    Full Text Available We study phase behaviour of a model fluid confined between two unlike parallel walls in the presence of long range (dispersion forces. Predictions obtained from macroscopic (geometric and mesoscopic arguments are compared with numerical solutions of a non-local density functional theory. Two capillary models are considered. For a capillary comprising two (differently adsorbing walls we show that simple geometric arguments lead to the generalized Kelvin equation locating very accurately capillary condensation, provided both walls are only partially wet. If at least one of the walls is in complete wetting regime, the Kelvin equation should be modified by capturing the effect of thick wetting films by including Derjaguin's correction. Within the second model, we consider a capillary formed of two competing walls, so that one tends to be wet and the other dry. In this case, an interface localized-delocalized transition occurs at bulk two-phase coexistence and a temperature T*(L depending on the pore width L. A mean-field analysis shows that for walls exhibiting first-order wetting transition at a temperature T_{w}, T_{s} > T*(L > T_{w}, where the spinodal temperature Ts can be associated with the prewetting critical temperature, which also determines a critical pore width below which the interface localized-delocalized transition does not occur. If the walls exhibit critical wetting, the transition is shifted below Tw and for a model with the binding potential W(l=A(Tl-2+B(Tl-3+..., where l is the location of the liquid-gas interface, the transition can be characterized by a dimensionless parameter κ=B/(AL, so that the fluid configuration with delocalized interface is stable in the interval between κ=-2/3 and κ ~ -0.23.

  11. Coalescence preference and droplet size inequality during fluid phase segregation

    Science.gov (United States)

    Roy, Sutapa

    2018-02-01

    Using molecular dynamics simulations and scaling arguments, we investigate the coalescence preference dynamics of liquid droplets in a phase-segregating off-critical, single-component fluid. It is observed that the preferential distance of the product drop from its larger parent, during a coalescence event, gets smaller for large parent size inequality. The relative coalescence position exhibits a power-law dependence on the parent size ratio with an exponent q ≃ 3.1 . This value of q is in strong contrast with earlier reports 2.1 and 5.1 in the literature. The dissimilarity is explained by considering the underlying coalescence mechanisms.

  12. Two-phase flow characteristics of HFC and HCFC fluid

    International Nuclear Information System (INIS)

    Ueno, T.; Matsuda, K.; Kusakabe, T.

    1998-01-01

    Some two-phase flow characteristics of HFC and HCFC fluid have been investigated experimentally. Fluids used in this experiment are HCFC22 (hereinafter called 'R22'), HCFC123 (hereinafter called 'R123') and Mixture of HFC fluid (hereinafter called 'R407C'). The fluid R407C are mixture of HFC32, HFC134a and HFC125, and their concentrations are 23wt%, 52wt% and 25wt%, respectively. This paper presents main flow parameters such as void fraction, interfacial velocities, bubble diameter distribution and pressure drop multiplier, which can characterize flow behavior. The void fractions and interfacial velocities were measured at some local positions in the single pipe using the bi-optical probe(hereinafter called 'BOP'). The procedure to calculate the void fraction from the void signals obtained by BOP were adopted the so-called slice method. The effects of slice levels on the void fraction were discussed taking into account bubble diameter. The new correlation of slice level as the function of void fraction has been proposed. The area-averaged void fractions obtained from BOP's void signals using new correlation were compared with void fractions obtained from pressure drops. The area-averaged interfacial velocities were also compared with the superficial gas velocities. It was concluded that the accuracy of BOP measurements are 5% for void fraction and less than 8.5% for interfacial velocity

  13. Immiscible two-phase fluid flows in deformable porous media

    Science.gov (United States)

    Lo, Wei-Cheng; Sposito, Garrison; Majer, Ernest

    Macroscopic differential equations of mass and momentum balance for two immiscible fluids in a deformable porous medium are derived in an Eulerian framework using the continuum theory of mixtures. After inclusion of constitutive relationships, the resulting momentum balance equations feature terms characterizing the coupling among the fluid phases and the solid matrix caused by their relative accelerations. These terms, which imply a number of interesting phenomena, do not appear in current hydrologic models of subsurface multiphase flow. Our equations of momentum balance are shown to reduce to the Berryman-Thigpen-Chen model of bulk elastic wave propagation through unsaturated porous media after simplification (e.g., isothermal conditions, neglect of gravity, etc.) and under the assumption of constant volume fractions and material densities. When specialized to the case of a porous medium containing a single fluid and an elastic solid, our momentum balance equations reduce to the well-known Biot model of poroelasticity. We also show that mass balance alone is sufficient to derive the Biot model stress-strain relations, provided that a closure condition for porosity change suggested by de la Cruz and Spanos is invoked. Finally, a relation between elastic parameters and inertial coupling coefficients is derived that permits the partial differential equations of the Biot model to be decoupled into a telegraph equation and a wave equation whose respective dependent variables are two different linear combinations of the dilatations of the solid and the fluid.

  14. Dynamic Studies of Lung Fluid Clearance with Phase Contrast Imaging

    International Nuclear Information System (INIS)

    Kitchen, Marcus J.; Williams, Ivan; Irvine, Sarah C.; Morgan, Michael J.; Paganin, David M.; Lewis, Rob A.; Pavlov, Konstantin; Hooper, Stuart B.; Wallace, Megan J.; Siu, Karen K. W.; Yagi, Naoto; Uesugi, Kentaro

    2007-01-01

    Clearance of liquid from the airways at birth is a poorly understood process, partly due to the difficulties of observing and measuring the distribution of air within the lung. Imaging dynamic processes within the lung in vivo with high contrast and spatial resolution is therefore a major challenge. However, phase contrast X-ray imaging is able to exploit inhaled air as a contrast agent, rendering the lungs of small animals visible due to the large changes in the refractive index at air/tissue interfaces. In concert with the high spatial resolution afforded by X-ray imaging systems (<100 μm), propagation-based phase contrast imaging is ideal for studying lung development. To this end we have utilized intense, monochromatic synchrotron radiation, together with a fast readout CCD camera, to study fluid clearance from the lungs of rabbit pups at birth. Local rates of fluid clearance have been measured from the dynamic sequences using a single image phase retrieval algorithm

  15. Novel Fluid Preservation System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for a method to preserve blood and urine samples from astronauts collected during flight, Chromologic (CL) proposes to develop a novel Fluid...

  16. Cosmic acceleration from a single fluid description

    Science.gov (United States)

    Capozziello, Salvatore; D'Agostino, Rocco; Luongo, Orlando

    2018-06-01

    We here propose a new class of barotropic factor for matter, motivated by properties of isotropic deformations of crystalline solids. Our approach is dubbed Anton-Schmidt's equation of state and provides a non-vanishing, albeit small, pressure term for matter. The corresponding pressure is thus proportional to the logarithm of universe's volume, i.e. to the density itself since V ∝ρ-1. In the context of solid state physics, we demonstrate that by only invoking standard matter with such a property, we are able to frame the universe speed up in a suitable way, without invoking a dark energy term by hand. Our model extends a recent class of dark energy paradigms named logotropic dark fluids and depends upon two free parameters, namely n and B. Within the Debye approximation, we find that n and B are related to the Grüneisen parameter and the bulk modulus of crystals. We thus show the main differences between our model and the logotropic scenario, and we highlight the most relevant properties of our new equation of state on the background cosmology. Discussions on both kinematics and dynamics of our new model have been presented. We demonstrate that the ΛCDM model is inside our approach, as limiting case. Comparisons with CPL parametrization have been also reported in the text. Finally, a Monte Carlo analysis on the most recent low-redshift cosmological data allowed us to place constraints on n and B. In particular, we found n = -0.147-0.107+0.113 and B = 3 . 54 × 10-3.

  17. Fluid phases of hydrogen-bound states and thermodynamical properties

    International Nuclear Information System (INIS)

    Ebeling, W.; Kraeft, W.D.

    1985-08-01

    The fluid phases of hydrogen and especially the existence of two critical points, the density dependence of the two - particle states and the effective interactions are discussed. An effective Schroedinger equation and a Saha equation are given. (author)

  18. Stability characteristics of a single-phase free convection loop

    Science.gov (United States)

    Creveling, H. F.; De Paz, J. F.; Baladi, J. Y.; Schoenhals, R. J.

    1975-01-01

    Experiments investigating the stability characteristics of a single-phase free convection loop are reported. Results of the study confirm the contention made by previous workers that instabilities near the thermodynamic critical point can occur for ordinary fluids as well as those with unusual behavior in the near-critical region. Such a claim runs counter to traditional beliefs, but it is supported by the observation of such instabilities for water at atmospheric pressure and moderate temperatures in the present work.

  19. Thermo-Fluid Dynamics of Two-Phase Flow

    CERN Document Server

    Ishii, Mamrou

    2011-01-01

    "Thermo-fluid Dynamics of Two-Phase Flow, Second Edition" is focused on the fundamental physics of two-phase flow. The authors present the detailed theoretical foundation of multi-phase flow thermo-fluid dynamics as they apply to: Nuclear reactor transient and accident analysis; Energy systems; Power generation systems; Chemical reactors and process systems; Space propulsion; Transport processes. This edition features updates on two-phase flow formulation and constitutive equations and CFD simulation codes such as FLUENT and CFX, new coverage of the lift force model, which is of part

  20. POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media

    KAUST Repository

    Wang, Yi; Yu, Bo; Sun, Shuyu

    2017-01-01

    Fast prediction modeling via proper orthogonal decomposition method combined with Galerkin projection is applied to incompressible single-phase fluid flow in porous media. Cases for different configurations of porous media, boundary conditions

  1. Preparation of single phase molybdenum boride

    International Nuclear Information System (INIS)

    Camurlu, Hasan Erdem

    2011-01-01

    Highlights: → Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides. → It is intricate to prepare single phase molybdenum borides. → Formation of single phase MoB from MoO 3 + B 2 O 3 + Mg mixtures has not been reported previously. → Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process. - Abstract: The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO 3 , B 2 O 3 and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo 2 B, MoB, MoB 2 and Mo 2 B 5 were found as minor phases. Products of MCS contained a mixture of Mo 2 B, MoB, MoB 2 and Mo. After annealing the MCS product at 1400 deg. C for 3 h, single phase α-MoB was obtained.

  2. A Thermodynamically Consistent Approach to Phase-Separating Viscous Fluids

    Science.gov (United States)

    Anders, Denis; Weinberg, Kerstin

    2018-04-01

    The de-mixing properties of heterogeneous viscous fluids are determined by an interplay of diffusion, surface tension and a superposed velocity field. In this contribution a variational model of the decomposition, based on the Navier-Stokes equations for incompressible laminar flow and the extended Korteweg-Cahn-Hilliard equations, is formulated. An exemplary numerical simulation using C1-continuous finite elements demonstrates the capability of this model to compute phase decomposition and coarsening of the moving fluid.

  3. Measurement of average density and relative volumes in a dispersed two-phase fluid

    Science.gov (United States)

    Sreepada, Sastry R.; Rippel, Robert R.

    1992-01-01

    An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

  4. Sampling device for withdrawing a representative sample from single and multi-phase flows

    Science.gov (United States)

    Apley, Walter J.; Cliff, William C.; Creer, James M.

    1984-01-01

    A fluid stream sampling device has been developed for the purpose of obtaining a representative sample from a single or multi-phase fluid flow. This objective is carried out by means of a probe which may be inserted into the fluid stream. Individual samples are withdrawn from the fluid flow by sampling ports with particular spacings, and the sampling parts are coupled to various analytical systems for characterization of the physical, thermal, and chemical properties of the fluid flow as a whole and also individually.

  5. Scaling of two-phase flow transients using reduced pressure system and simulant fluid

    International Nuclear Information System (INIS)

    Kocamustafaogullari, G.; Ishii, M.

    1987-01-01

    Scaling criteria for a natural circulation loop under single-phase flow conditions are derived. Based on these criteria, practical applications for designing a scaled-down model are considered. Particular emphasis is placed on scaling a test model at reduced pressure levels compared to a prototype and on fluid-to-fluid scaling. The large number of similarty groups which are to be matched between modell and prototype makes the design of a scale model a challenging tasks. The present study demonstrates a new approach to this clasical problen using two-phase flow scaling parameters. It indicates that a real time scaling is not a practical solution and a scaled-down model should have an accelerated (shortened) time scale. An important result is the proposed new scaling methodology for simulating pressure transients. It is obtained by considerung the changes of the fluid property groups which appear within the two-phase similarity parameters and the single-phase to two-phase flow transition prameters. Sample calculations are performed for modeling two-phase flow transients of a high pressure water system by a low-pressure water system or a Freon system. It is shown that modeling is possible for both cases for simulation pressure transients. However, simulation of phase change transitions is not possible by a reduced pressure water system without distortion in either power or time. (orig.)

  6. Single phase induction motor with starting performance

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, M.; Demeter, E. [Research Institute for Electrical Machines, ICPE-ME, Bucharest (Romania); Navrapescu, V. [University `Politehnica` Bucharest, Electrical Engineering Faculty Splaiul Independentei, Bucharest (Romania)

    1997-12-31

    The paper presents problems related to a special type of single phase induction motor. The main novelty consists in the use of a conducting (aluminium casted) shell distributed on the periferic region of the rotor. As a result the starting performance, as well as the rated ones, is much improved in comparison with the conventional construction. (orig.) 4 refs.

  7. Control of Single-Stage Single-Phase PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

  8. Geometry-induced phase transition in fluids: Capillary prewetting

    OpenAIRE

    Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

    2013-01-01

    We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangu...

  9. Lattice Boltzmann model for three-phase viscoelastic fluid flow

    Science.gov (United States)

    Xie, Chiyu; Lei, Wenhai; Wang, Moran

    2018-02-01

    A lattice Boltzmann (LB) framework is developed for simulation of three-phase viscoelastic fluid flows in complex geometries. This model is based on a Rothman-Keller type model for immiscible multiphase flows which ensures mass conservation of each component in porous media even for a high density ratio. To account for the viscoelastic effects, the Maxwell constitutive relation is correctly introduced into the momentum equation, which leads to a modified lattice Boltzmann evolution equation for Maxwell fluids by removing the normal but excess viscous term. Our simulation tests indicate that this excess viscous term may induce significant errors. After three benchmark cases, the displacement processes of oil by dispersed polymer are studied as a typical example of three-phase viscoelastic fluid flow. The results show that increasing either the polymer intrinsic viscosity or the elastic modulus will enhance the oil recovery.

  10. Diffusion in porous structures containing three fluid phases

    International Nuclear Information System (INIS)

    Galani, A.N.; Kainourgiakis, M.E.; Stubos, A.K.; Kikkinides, E.S.

    2005-01-01

    In the present study, the tracer diffusion in porous media filled by three fluid phases (a non-wetting, an intermediate wetting and a wetting phase) is investigated. The disordered porous structure of porous systems like random sphere packing and the North Sea chalk, is represented by three-dimensional binary images. The random sphere pack is generated by a standard ballistic deposition procedure, while the chalk matrix by a stochastic reconstruction technique. Physically sound spatial distributions of the three phases filling the pore space are determined by the use of a simulated annealing algorithm, where those phases are initially randomly distributed in the pore space and trial-and-error swaps are performed in order to attain the global minimum of the total interfacial energy. The acceptance rule for a trial move during the annealing is modified properly improving the efficiency of the technique. The diffusivities of the resulting domains are computed by a random walk method. A parametric study with respect to the pore volume fraction occupied by each fluid phase and the ratio of the diffusivities in the fluid phases is performed. (authors)

  11. Mass transfer processes in crystalline aggregates containing a fluid phase

    NARCIS (Netherlands)

    Visser, H.J.M.

    1999-01-01

    Understanding mass transfer processes in porous crystalline aggregates containing a fluid phase is of major importance for modelling partially molten regions of the Earth's mantle, such as those under mid-ocean spreading ridges. Despite the fact that mid-ocean ridges can be considered the

  12. Mass transfer processes in crystalline aggregates containing a fluid phase

    NARCIS (Netherlands)

    Visser, H.J.M.

    1999-01-01

    Understanding mass transfer processes in porous crystalline aggregates containing a fluid phase is of major importance for modelling partially molten regions of the Earth's mantle, such as those under mid-ocean spreading ridges. Despite the fact that mid-ocean ridges can be considered the simplest

  13. Introduction to investigations of the negative corona and EHD flow in gaseous two-phase fluids

    Science.gov (United States)

    Jerzy, MIZERACZYK; Artur, BERENDT

    2018-05-01

    Research interests have recently been directed towards electrical discharges in multi-phase environments. Natural electrical discharges, such as lightning and coronas, occur in the Earth’s atmosphere, which is actually a mixture of gaseous phase (air) and suspended solid and liquid particulate matters (PMs). An example of an anthropogenic gaseous multi-phase environment is the flow of flue gas through electrostatic precipitators (ESPs), which are generally regarded as a mixture of a post-combustion gas with solid PM and microdroplets suspended in it. Electrical discharges in multi-phase environments, the knowledge of which is scarce, are becoming an attractive research subject, offering a wide variety of possible discharges and multi-phase environments to be studied. This paper is an introduction to electrical discharges in multi-phase environments. It is focused on DC negative coronas and accompanying electrohydrodynamic (EHD) flows in a gaseous two-phase fluid formed by air (a gaseous phase) and solid PM (a solid phase), run under laboratory conditions. The introduction is based on a review of the relevant literature. Two cases will be considered: the first case is of a gaseous two-phase fluid, initially motionless in a closed chamber before being subjected to a negative corona (with the needle-to-plate electrode arrangement), which afterwards induces an EHD flow in the chamber, and the second, of a gaseous two-phase fluid flowing transversely with respect to the needle-to-plate electrode axis along a chamber with a corona discharge running between the electrodes. This review-based introductory paper should be of interest to theoretical researchers and modellers in the field of negative corona discharges in single- or two-phase fluids, and for engineers who work on designing EHD devices (such as ESPs, EHD pumps, and smoke detectors).

  14. Validation of model predictions of pore-scale fluid distributions during two-phase flow

    Science.gov (United States)

    Bultreys, Tom; Lin, Qingyang; Gao, Ying; Raeini, Ali Q.; AlRatrout, Ahmed; Bijeljic, Branko; Blunt, Martin J.

    2018-05-01

    Pore-scale two-phase flow modeling is an important technology to study a rock's relative permeability behavior. To investigate if these models are predictive, the calculated pore-scale fluid distributions which determine the relative permeability need to be validated. In this work, we introduce a methodology to quantitatively compare models to experimental fluid distributions in flow experiments visualized with microcomputed tomography. First, we analyzed five repeated drainage-imbibition experiments on a single sample. In these experiments, the exact fluid distributions were not fully repeatable on a pore-by-pore basis, while the global properties of the fluid distribution were. Then two fractional flow experiments were used to validate a quasistatic pore network model. The model correctly predicted the fluid present in more than 75% of pores and throats in drainage and imbibition. To quantify what this means for the relevant global properties of the fluid distribution, we compare the main flow paths and the connectivity across the different pore sizes in the modeled and experimental fluid distributions. These essential topology characteristics matched well for drainage simulations, but not for imbibition. This suggests that the pore-filling rules in the network model we used need to be improved to make reliable predictions of imbibition. The presented analysis illustrates the potential of our methodology to systematically and robustly test two-phase flow models to aid in model development and calibration.

  15. Fluid-elastic vibration in two-phase cross flow

    International Nuclear Information System (INIS)

    Sasakawa, T.; Serizawa, A.; Kawara, Z.

    2003-01-01

    The present work aims at clarifying the mechanisms of fluid elastic vibration of tube bundles in two-phase cross flow. The experiment is conducted using air-water two-phase flow under atmospheric pressure. The test section is a 1.03m long transparent acrylic square duct with 128 x 128 mm 2 cross section, which consists of 3 rod-rows with 5 rods in each row. The rods are 125mm long aluminum rods with 22 mm in diameter (p/D=1.45). The natural frequency of rod vibration is about 30Hz. The result indicated a diversion of observed trend in vibration behavior depending on two-phase flow patterns either bubbly flow or churn flow. Specifically, in churn flow, the fluid elastic vibration has been observed to occur when the frequency in void fraction fluctuation approached to the natural frequency of the rods, but this was not the case in fluid elastic vibration in bubbly flow. This fact suggests the existence of mechanisms closely coupled with two-phase flow structures depending on the flow patterns, that is, static two-phase character-controlled mechanism in bubbly flow and dynamic character- controlled in churn flow

  16. Load compensation for single phase system using series active filter

    African Journals Online (AJOL)

    user

    Keywords: Active power filter (APF), current source type of harmonic load ... Single phase active filters could attract less attention than three phase due to its low ..... Generalised single-phase p-q theory for active power filtering: simulation and.

  17. Direct numerical simulations of fluid flow, heat transfer and phase changes

    Science.gov (United States)

    Juric, D.; Tryggvason, G.; Han, J.

    1997-01-01

    Direct numerical simulations of fluid flow, heat transfer, and phase changes are presented. The simulations are made possible by a recently developed finite difference/front tracking method based on the one-field formulation of the governing equations where a single set of conservation equations is written for all the phases involved. The conservation equations are solved on a fixed rectangular grid, but the phase boundaries are kept sharp by tracking them explicitly by a moving grid of lower dimension. The method is discussed and applications to boiling heat transfer and the solidification of drops colliding with a wall are shown.

  18. Numerical modeling of two-phase binary fluid mixing using mixed finite elements

    KAUST Repository

    Sun, Shuyu

    2012-07-27

    Diffusion coefficients of dense gases in liquids can be measured by considering two-phase binary nonequilibrium fluid mixing in a closed cell with a fixed volume. This process is based on convection and diffusion in each phase. Numerical simulation of the mixing often requires accurate algorithms. In this paper, we design two efficient numerical methods for simulating the mixing of two-phase binary fluids in one-dimensional, highly permeable media. Mathematical model for isothermal compositional two-phase flow in porous media is established based on Darcy\\'s law, material balance, local thermodynamic equilibrium for the phases, and diffusion across the phases. The time-lag and operator-splitting techniques are used to decompose each convection-diffusion equation into two steps: diffusion step and convection step. The Mixed finite element (MFE) method is used for diffusion equation because it can achieve a high-order and stable approximation of both the scalar variable and the diffusive fluxes across grid-cell interfaces. We employ the characteristic finite element method with moving mesh to track the liquid-gas interface. Based on the above schemes, we propose two methods: single-domain and two-domain methods. The main difference between two methods is that the two-domain method utilizes the assumption of sharp interface between two fluid phases, while the single-domain method allows fractional saturation level. Two-domain method treats the gas domain and the liquid domain separately. Because liquid-gas interface moves with time, the two-domain method needs work with a moving mesh. On the other hand, the single-domain method allows the use of a fixed mesh. We derive the formulas to compute the diffusive flux for MFE in both methods. The single-domain method is extended to multiple dimensions. Numerical results indicate that both methods can accurately describe the evolution of the pressure and liquid level. © 2012 Springer Science+Business Media B.V.

  19. Multi-scale Modeling of Compressible Single-phase Flow in Porous Media using Molecular Simulation

    KAUST Repository

    Saad, Ahmed Mohamed

    2016-01-01

    potential model that accounts for the molecular quadrupole moment of fluids with non-spherical molecules such as CO2. The potential model was used to simulate the thermodynamic equilibrium properties for single-phase and two-phase systems using the canonical

  20. Uniform phases in fluids of hard isosceles triangles: One-component fluid and binary mixtures

    Science.gov (United States)

    Martínez-Ratón, Yuri; Díaz-De Armas, Ariel; Velasco, Enrique

    2018-05-01

    We formulate the scaled particle theory for a general mixture of hard isosceles triangles and calculate different phase diagrams for the one-component fluid and for certain binary mixtures. The fluid of hard triangles exhibits a complex phase behavior: (i) the presence of a triatic phase with sixfold symmetry, (ii) the isotropic-uniaxial nematic transition is of first order for certain ranges of aspect ratios, and (iii) the one-component system exhibits nematic-nematic transitions ending in critical points. We found the triatic phase to be stable not only for equilateral triangles but also for triangles of similar aspect ratios. We focus the study of binary mixtures on the case of symmetric mixtures: equal particle areas with aspect ratios (κi) symmetric with respect to the equilateral one, κ1κ2=3 . For these mixtures we found, aside from first-order isotropic-nematic and nematic-nematic transitions (the latter ending in a critical point): (i) a region of triatic phase stability even for mixtures made of particles that do not form this phase at the one-component limit, and (ii) the presence of a Landau point at which two triatic-nematic first-order transitions and a nematic-nematic demixing transition coalesce. This phase behavior is analogous to that of a symmetric three-dimensional mixture of rods and plates.

  1. Fluid dynamics of cryogenic two-phase flows

    International Nuclear Information System (INIS)

    Verfondern, K.; Jahn, W.

    2004-01-01

    The objective of this study was to examine the flow behavior of a methane hydrate/methane-liquid hydrogen dispersed two-phase fluid through a given design of a moderator chamber for the ESS target system. The calculations under simplified conditions, e.g., taking no account of heat input from outside, have shown that the computer code used, CFX, was able to simulate the behavior of the two-phase flow through the moderator chamber, producing reasonable results up to a certain level of the solid phase fraction, that allowed a continuous flow process through the chamber. Inlet flows with larger solid phase fractions than 40 vol% were found to be a ''problem'' for the computer code. From the computer runs based on fractions between 20 and 40 vol%, it was observed that with increasing solid phase fraction at the inlet, the resulting flow pattern revealed a strong tendency for blockage within the chamber, supported by the ''heavy weight'' of the pellets compared to the carrying liquid. Locations which are prone to the development of such uneven flow behavior are the areas around the turning points in the semispheres and near the exit of the moderator. The considered moderator chamber with horizontal inlet and outlet flow for a solid-liquid two-phase fluid does not seem to be an appropriate design. (orig.)

  2. The mechanism of reequilibration of solids in the presence of a fluid phase

    International Nuclear Information System (INIS)

    Putnis, Andrew; Putnis, Christine V.

    2007-01-01

    The preservation of morphology (pseudomorphism) and crystal structure during the transformation of one solid phase to another is regularly used as a criterion for a solid-state mechanism, even when there is a fluid phase present. However, a coupled dissolution-reprecipitation mechanism also preserves the morphology and transfers crystallographic information from parent to product by epitaxial nucleation. The generation of porosity in the product phase is a necessary condition for such a mechanism as it allows fluid to maintain contact with a reaction interface which moves through the parent phase from the original surface. We propose that interface-coupled dissolution-reprecipitation is a general mechanism for reequilibration of solids in the presence of a fluid phase. - Graphical abstract: A single crystal of KBr is transformed to a porous single crystal of KCl by immersion in saturated KCl solution. The image shows partial transformation of a crystal of KBr (core) to KCl (porous, milky rim) by an interface coupled dissolution-reprecipitation mechanism. The external dimensions and crystallographic orientation of the original crystal are preserved, while a reaction interface moves through the crystal

  3. Single-Use Poly(etheretherketone) Solid-Phase Microextraction-Transmission Mode Devices for Rapid Screening and Quantitation of Drugs of Abuse in Oral Fluid and Urine via Direct Analysis in Real-Time Tandem Mass Spectrometry.

    Science.gov (United States)

    Vasiljevic, Tijana; Gómez-Ríos, Germán Augusto; Pawliszyn, Janusz

    2018-01-02

    The analysis of oral fluid (OF) and urine samples to detect drug consumption has garnered considerable attention as alternative biomatrices. Efficient implementation of microextraction and ambient ionization technologies for rapid detection of target compounds in such biomatrices creates a need for biocompatible devices which can be implemented for in vivo sampling and easily interfaced with mass spectrometry (MS) analyzers. This study introduces a novel solid-phase microextraction-transmission mode (SPME-TM) device made of poly(etheretherketone) (PEEK) mesh that can rapidly detect prohibited substances in biofluids via direct analysis in real-time tandem MS (DART-MS/MS). PEEK mesh was selected due to its biocompatibility, excellent resistance to various organic solvents, and its ability to withstand relatively high temperatures (≤350 °C). The meshes were coated with hydrophilic-lipophilic-balance particle-poly(acrylonitrile) (HLB-PAN) slurry. The robustness of the coated meshes was tested by performing rapid vortex agitation (≥3200 rpm) in LC/MS-grade solvents and by exposing them to the DART source jet stream at typical operational temperatures (∼250-350 °C). PEEK SPME-TM devices proved to be robust and were therefore used to perform ex vivo analysis of drugs of abuse spiked in urine and OF samples. Excellent results were obtained for all analytes under study; furthermore, the tests yielded satisfactory limits of quantitation (median, ∼0.5 ng mL -1 ), linearity (≥0.99), and accuracy (80-120%) over the evaluated range (0.5-200 ng mL -1 ). This research highlights plastic SPME-TM's potential usefulness as a method for rapidly screening for prohibited substances in on-site/in vivo scenarios, such as roadside or workplace drug testing, antidoping controls, and pain management programs.

  4. Geometry-induced phase transition in fluids: capillary prewetting.

    Science.gov (United States)

    Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

    2013-02-01

    We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangular pore exerting long-ranged dispersion forces on the fluid. In the T-μ plane the phase line of the new transition is tangential to the capillary condensation line at the capillary wetting temperature T(cw). The surface phase behavior of the system maps to planar wetting with the phase line of the new transition, termed capillary prewetting, mapping to the planar prewetting line. If capillary condensation is approached isothermally with T>T(cw), the meniscus forms at the capping wall and unbinds continuously, making capillary condensation a second-order phenomenon. We compute the corresponding critical exponent for the divergence of adsorption.

  5. Coupling two-phase fluid flow with two-phase darcy flow in anisotropic porous media

    KAUST Repository

    Chen, J.

    2014-06-03

    This paper reports a numerical study of coupling two-phase fluid flow in a free fluid region with two-phase Darcy flow in a homogeneous and anisotropic porous medium region. The model consists of coupled Cahn-Hilliard and Navier-Stokes equations in the free fluid region and the two-phase Darcy law in the anisotropic porous medium region. A Robin-Robin domain decomposition method is used for the coupled Navier-Stokes and Darcy system with the generalized Beavers-Joseph-Saffman condition on the interface between the free flow and the porous media regions. Obtained results have shown the anisotropic properties effect on the velocity and pressure of the two-phase flow. 2014 Jie Chen et al.

  6. Coupling Two-Phase Fluid Flow with Two-Phase Darcy Flow in Anisotropic Porous Media

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2014-06-01

    Full Text Available This paper reports a numerical study of coupling two-phase fluid flow in a free fluid region with two-phase Darcy flow in a homogeneous and anisotropic porous medium region. The model consists of coupled Cahn-Hilliard and Navier-Stokes equations in the free fluid region and the two-phase Darcy law in the anisotropic porous medium region. A Robin-Robin domain decomposition method is used for the coupled Navier-Stokes and Darcy system with the generalized Beavers-Joseph-Saffman condition on the interface between the free flow and the porous media regions. Obtained results have shown the anisotropic properties effect on the velocity and pressure of the two-phase flow.

  7. Assessment of magnetic fluid stability in non-homogeneous magnetic field of a single-tooth magnetic fluid sealer

    Energy Technology Data Exchange (ETDEWEB)

    Arefyev, I.M.; Demidenko, O.V.; Saikin, M.S.

    2017-06-01

    A special experimental stand has been developed and made to test magnetic fluid. It represents a single-tooth magnetic fluid sealer. The type of dependence of the pressure differential on magnetic fluid sealer operation time is used as a criterion to determine magnetic fluid stability and magnetic fluid sealer service life under such conditions. The siloxane-based magnetic fluid was used as the test sample. The colloidal stability as well as stability of the synthesized magnetic fluid in magnetic fields in static mode were determined. It has been found that the obtained magnetic fluid is stable in static mode and, consequently, can be used to conduct necessary tests on stand. Short-term and life tests on stand have shown that MF remains stable and efficient for at least 360 days of continuous utilization. - Highlights: • An experimental single-tooth magnetic fluid sealer has been developed and made. • The magnetic fluid based on siloxane liquid was used as the test sample. • Short-term and life tests of the magnetic fluid were conducted. • The magnetic fluid stability was determined by necessary tests on stand.

  8. Single-Receiver GPS Phase Bias Resolution

    Science.gov (United States)

    Bertiger, William I.; Haines, Bruce J.; Weiss, Jan P.; Harvey, Nathaniel E.

    2010-01-01

    Existing software has been modified to yield the benefits of integer fixed double-differenced GPS-phased ambiguities when processing data from a single GPS receiver with no access to any other GPS receiver data. When the double-differenced combination of phase biases can be fixed reliably, a significant improvement in solution accuracy is obtained. This innovation uses a large global set of GPS receivers (40 to 80 receivers) to solve for the GPS satellite orbits and clocks (along with any other parameters). In this process, integer ambiguities are fixed and information on the ambiguity constraints is saved. For each GPS transmitter/receiver pair, the process saves the arc start and stop times, the wide-lane average value for the arc, the standard deviation of the wide lane, and the dual-frequency phase bias after bias fixing for the arc. The second step of the process uses the orbit and clock information, the bias information from the global solution, and only data from the single receiver to resolve double-differenced phase combinations. It is called "resolved" instead of "fixed" because constraints are introduced into the problem with a finite data weight to better account for possible errors. A receiver in orbit has much shorter continuous passes of data than a receiver fixed to the Earth. The method has parameters to account for this. In particular, differences in drifting wide-lane values must be handled differently. The first step of the process is automated, using two JPL software sets, Longarc and Gipsy-Oasis. The resulting orbit/clock and bias information files are posted on anonymous ftp for use by any licensed Gipsy-Oasis user. The second step is implemented in the Gipsy-Oasis executable, gd2p.pl, which automates the entire process, including fetching the information from anonymous ftp

  9. Numerical investigation on lateral migration and lift force of single bubble in simple shear flow in low viscosity fluid using volume of fluid method

    International Nuclear Information System (INIS)

    Zhongchun, Li; Xiaoming, Song; Shengyao, Jiang; Jiyang, Yu

    2014-01-01

    Highlights: • A VOF simulation of bubble in low viscosity fluid was conducted. • Lift force in different viscosity fluid had different lateral migration characteristics. • Bubble with different size migrated to different direction. • Shear stress triggered the bubble deformation process and the bubble deformation came along with the oscillation behaviors. - Abstract: Two phase flow systems have been widely used in industrial engineering. Phase distribution characteristics are vital to the safety operation and optimization design of two phase flow systems. Lift force has been known as perpendicular to the bubbles’ moving direction, which is one of the mechanisms of interfacial momentum transfer. While most widely used lift force correlations, such as the correlation of Tomiyama et al. (2002), were obtained by experimentally tracking single bubble trajectories in high viscosity glycerol–water mixture, the applicability of these models into low viscosity fluid, such as water in nuclear engineering system, needs to be further evaluated. In the present paper, bubble in low viscosity fluid in shear flow was investigated in a full 3D numerical simulation and the volume of fluid (VOF) method was applied to capture the interface. The fluid parameter: fluid viscosity, bubble parameter: diameter and external flow parameters: shear stress magnitude and liquid velocity were examined. Comparing with bubble in high viscosity shear flow and bubble in low viscosity still flow, relative large bubble in low viscosity shear flow keep an oscillation way towards the moving wall and experienced a shape deformation process. The oscillation amplitude increased as the viscosity of fluid decreased. Small bubble migrated to the static wall in a line with larger migration velocity than that in high viscosity fluid and no deformation occurred. The shear stress triggered the oscillation behaviors while it had no direct influence with the behavior. The liquid velocity had no effect on

  10. Domain switching in single-phase multiferroics

    Science.gov (United States)

    Jia, Tingting; Cheng, Zhenxiang; Zhao, Hongyang; Kimura, Hideo

    2018-06-01

    Multiferroics are a time-honoured research subject by reason for their tremendous application potential in the information industry, such as in multi-state information storage devices and new types of sensors. An outburst of studies on multiferroicity has been witnessed in the 21st century, although this field has a long research history since the 19th century. Multiferroicity has now become one of the hottest research topics in condensed matter physics and materials science. Numerous efforts have been made to investigate the cross-coupling phenomena among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, and ferroelasticity, especially the coupling between electric and magnetic orderings that would account for the magnetoelectric (ME) effect in multiferroic materials. The magnetoelectric properties and coupling behavior of single phase multiferroics are dominated by their domain structures. It was also noted that, however, the multiferroic materials exhibit very complicated domain structures. Studies on domain structure characterization and domain switching are a crucial step in the exploration of approaches to the control and manipulation of magnetic (electric) properties using an electric (magnetic) field or other means. In this review, following a concise outline of our current basic knowledge on the magnetoelectric (ME) effect, we summarize some important research activities on domain switching in single-phase multiferroic materials in the form of single crystals and thin films, especially domain switching behavior involving strain and the related physics in the last decade. We also introduce recent developments in characterization techniques for domain structures of ferroelectric or multiferroic materials, which have significantly advanced our understanding of domain switching dynamics and interactions. The effects of a series of issues such as electric field, magnetic field, and stress effects on domain switching are been discussed as well. It

  11. Phase separation in fluids exposed to spatially periodic external fields.

    Science.gov (United States)

    Vink, R L C; Archer, A J

    2012-03-01

    When a fluid is confined within a spatially periodic external field, the liquid-vapor transition is replaced by a different transition called laser-induced condensation (LIC) [Götze et al., Mol. Phys. 101, 1651 (2003)]. In d=3 dimensions, the periodic field induces an additional phase, characterized by large density modulations along the field direction. At the triple point, all three phases (modulated, vapor, and liquid) coexist. At temperatures slightly above the triple point and for low (high) values of the chemical potential, two-phase coexistence between the modulated phase and the vapor (liquid) is observed; by increasing the temperature further, both coexistence regions terminate in critical points. In this paper, we reconsider LIC using the Ising model to resolve a number of open issues. To be specific, we (1) determine the universality class of the LIC critical points and elucidate the nature of the correlations along the field direction, (2) present a mean-field analysis to show how the LIC phase diagram changes as a function of the field wavelength and amplitude, (3) develop a simulation method by which the extremely low tension of the interface between modulated and vapor or liquid phase can be measured, (4) present a finite-size scaling analysis to accurately extract the LIC triple point from finite-size simulation data, and (5) consider the fate of LIC in d=2 dimensions.

  12. Studying Validity of Single-Fluid Model in Inertial Confinement Fusion

    International Nuclear Information System (INIS)

    Gu Jian-Fa; Fan Zheng-Feng; Dai Zhen-Sheng; Ye Wen-Hua; Pei Wen-Bing; Zhu Shao-Ping

    2014-01-01

    The validity of single-fluid model in inertial confinement fusion simulations is studied by comparing the results of the multi- and single-fluid models. The multi-fluid model includes the effects of collision and interpenetration between fluid species. By simulating the collision of fluid species, steady-state shock propagation into the thin DT gas and expansion of hohlraum Au wall heated by lasers, the results show that the validity of single-fluid model is strongly dependent on the ratio of the characteristic length of the simulated system to the particle mean free path. When the characteristic length L is one order larger than the mean free path λ, the single-fluid model's results are found to be in good agreement with the multi-fluid model's simulations, and the modeling of single-fluid remains valid. If the value of L/λ is lower than 10, the interpenetration between fluid species is significant, and the single-fluid simulations show some unphysical results; while the multi-fluid model can describe well the interpenetration and mix phenomena, and give more reasonable results. (physics of gases, plasmas, and electric discharges)

  13. Instability of single-phase natural circulation

    International Nuclear Information System (INIS)

    Xie Heng; Zhang Jinling; Jia Dounan

    1997-01-01

    The author has investigated the instability of single-phase flows in natural circulation loops. The momentum equation and energy equation are made dimensionless according to some definitions, and some important dimensionless parameters are gotten. The authors decomposed the mean mass flowrate and temperature into a steady solution and a small disturbance equations. Through solving the disturbance equations, the authors get the neutral stability curves. The authors have studied the effect of the two parameters which represent the ratio of buoyancy force to the friction loss in the loop on the stability of loops. The authors also have studied the effect of the difference of height between the center of heat source and the heat sink on the stability

  14. Density and Phase State of a Confined Nonpolar Fluid

    Science.gov (United States)

    Kienle, Daniel F.; Kuhl, Tonya L.

    2016-07-01

    Measurements of the mean refractive index of a spherelike nonpolar fluid, octamethytetracylclosiloxane (OMCTS), confined between mica sheets, demonstrate direct and conclusive experimental evidence of the absence of a first-order liquid-to-solid phase transition in the fluid when confined, which has been suggested to occur from previous experimental and simulation results. The results also show that the density remains constant throughout confinement, and that the fluid is incompressible. This, along with the observation of very large increases (many orders of magnitude) in viscosity during confinement from the literature, demonstrate that the molecular motion is limited by the confining wall and not the molecular packing. In addition, the recently developed refractive index profile correction method, which enables the structural perturbation inherent at a solid-liquid interface and that of a liquid in confinement to be determined independently, was used to show that there was no measurable excess or depleted mass of OMCTS near the mica surface in bulk films or confined films of only two molecular layers.

  15. Coupling two-phase fluid flow with two-phase darcy flow in anisotropic porous media

    KAUST Repository

    Chen, J.; Sun, S.; Chen, Z.

    2014-01-01

    in the free fluid region and the two-phase Darcy law in the anisotropic porous medium region. A Robin-Robin domain decomposition method is used for the coupled Navier-Stokes and Darcy system with the generalized Beavers-Joseph-Saffman condition

  16. Thermodynamic Property Model of Wide-Fluid Phase Propane

    Directory of Open Access Journals (Sweden)

    I Made Astina

    2007-05-01

    Full Text Available A new thermodynamic property model for propane is expressed in form of the Helmholtz free energy function. It consists of eight terms of the ideal-gas part and eighteen terms of the residual part. Accurate experimental data of fluid properties and theoretical approach from the intermolecular potential were simultaneously considered in the development to insure accuracy and to improve reliability of the equation of state over wide range of pressures and temperatures. Based on the state range of experimental data used in the model development, the validity range is judged from the triple-point of 85.48 K to temperature of 450 K and pressure up to 60 MPa. The uncertainties with respect to different properties are estimated to be 0.03% in ideal-gas isobaric specific heat, 0.2% in liquid phase density, 0.3% in gaseous phase density 1% in specific heats, 0.1% in vapor-pressure except at very low temperatures, 0.05% in saturated-liquid density, 0.02% in speed of sound of the gaseous phase and 1% in speed of sound of the liquid phase.

  17. Numerical simulation of complex multi-phase fluid of casting process and its applications

    Directory of Open Access Journals (Sweden)

    CHEN Li-liang

    2006-05-01

    Full Text Available The fluid of casting process is a typical kind of multi-phase flow. Actually, many casting phenomena have close relationship with the multi-phase flow, such as molten metal filling process, air entrapment, slag movement, venting process of die casting, gas escaping of lost foam casting and so on. Obviously, in order to analyze these phenomena accurately, numerical simulation of the multi-phase fluid is necessary. Unfortunately, so far, most of the commercial casting simulation systems do not have the ability of multi-phase flow modeling due to the difficulty in the multi-phase flow calculation. In the paper, Finite Different Method (FDM technique was adopt to solve the multi-phase fluid model. And a simple object of the muiti-phase fluid was analyzed to obtain the fluid rates of the liquid phase and the entrapped air phase.

  18. Dynamic dielectrophoresis model of multi-phase ionic fluids.

    Directory of Open Access Journals (Sweden)

    Ying Yan

    Full Text Available Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

  19. Dynamic dielectrophoresis model of multi-phase ionic fluids.

    Science.gov (United States)

    Yan, Ying; Luo, Jing; Guo, Dan; Wen, Shizhu

    2015-01-01

    Ionic-based dielectrophoretic microchips have attracted significant attention due to their wide-ranging applications in electro kinetic and biological experiments. In this work, a numerical method is used to simulate the dynamic behaviors of ionic droplets in a microchannel under the effect of dielectrophoresis. When a discrete liquid dielectric is encompassed within a continuous fluid dielectric placed in an electric field, an electric force is produced due to the dielectrophoresis effect. If either or both of the fluids are ionic liquids, the magnitude and even the direction of the force will be changed because the net ionic charge induced by an electric field can affect the polarization degree of the dielectrics. However, using a dielectrophoresis model, assuming ideal dielectrics, results in significant errors. To avoid the inaccuracy caused by the model, this work incorporates the electrode kinetic equation and defines a relationship between the polarization charge and the net ionic charge. According to the simulation conditions presented herein, the electric force obtained in this work has an error exceeding 70% of the actual value if the false effect of net ionic charge is not accounted for, which would result in significant issues in the design and optimization of experimental parameters. Therefore, there is a clear motivation for developing a model adapted to ionic liquids to provide precise control for the dielectrophoresis of multi-phase ionic liquids.

  20. Fluid dynamics of airlift reactors; Two-phase friction factors

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Calvo, E. (Ingenieria Quimica, Facultad de Ciencias, Univ. de Alcala, 28871 Alcala de Henares (Spain))

    1992-10-01

    Airlift loop reactors (ALR) are useful equipment in biotechnology in a wide range of uses, however their design is not a simple task since prediction of fluid dynamics in these reactors is difficult. Most of the different strategies found in the literature in order to predict two main parameters, namely, gas holdup and liquid velocity, are based on energy or momentum balances. The balances include frictional effects, and it is not yet clear how to predict these effects. The objective of this article is to show how criteria corresponding to one-phase flow may be used in order to predict the frictional effects in ALRs. Based on a model proposed by Garcia-Calvo (1989, 1991), we simulated experimental data of liquid velocity profiles and gas holdup obtained by Young et al. in an ALR with two different configurations. Experimental data obtained in other three external ALRs with different shapes and sizes are also simulated.

  1. Lennard-Jones fluids in two-dimensional nano-pores. Multi-phase coexistence and fluid structure

    Science.gov (United States)

    Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

    2014-03-01

    We present a number of fundamental findings on the wetting behaviour of nano-pores. A popular model for fluid confinement is a one-dimensional (1D) slit pore formed by two parallel planar walls and it exhibits capillary condensation (CC): a first-order phase transition from vapour to capillary-liquid (Kelvin shift). Capping such a pore at one end by a third orthogonal wall forms a prototypical two-dimensional (2D) pore. We show that 2D pores possess a wetting temperature such that below this temperature CC remains of first order, above it becomes a continuous phase transition manifested by a slab of capillary-liquid filling the pore from the capping wall. Continuous CC exhibits hysteresis and can be preceded by a first-order capillary prewetting transition. Additionally, liquid drops can form in the corners of the 2D pore (remnant of 2D wedge prewetting). The three fluid phases, vapour, capillary-liquid slab and corner drops, can coexist at the pore triple point. Our model is based on the statistical mechanics of fluids in the density functional formulation. The fluid-fluid and fluid-substrate interactions are dispersive. We analyze in detail the microscopic fluid structure, isotherms and full phase diagrams. Our findings also suggest novel ways to control wetting of nano-pores. We are grateful to the European Research Council via Advanced Grant No. 247031 for support.

  2. Computer analysis of an adiabatic Stirling cryocooler using a two-phase two-component working fluid

    International Nuclear Information System (INIS)

    Renfroe, D.A.; Cheung, C.M.

    1992-01-01

    This paper describes the performance and behavior of a Stirling cyrocooler incorporating a working fluid composed of helium and nitrogen. At the operating temperature of the cryocooler (80 K), the nitrogen component will condense in the freezer section. It is shown that the phase change in the working fluid increased the heat lifted for a given size and weight of machine and the coefficient of performance. The magnitude of these effects was dependent on the mass ratio of nitrogen to helium, phase angle between the compression and expansion processes, and the ratio of the compression space volume to the expansion space volume. The optimum heat lifted performance was obtained for a mass ratio of four parts of nitrogen to one part of helium, a phase angle of approximately 100 degrees, and a volume ratio of two which resulted in a heat lifted increase of 75% over the single phase, 90 degree phase angle configuration. The coefficient of performance showed a 20% improvement

  3. Co-existence of Gel and Fluid Lipid Domains in Single-component Phospholipid Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Clare L [McMaster University; Barrett, M [McMaster University; Toppozini, L [McMaster University; Yamani, Zahra [Canadian Neutron Beam Centre, National Research Council, Chalk River Laboratorie; Kucerka, Norbert [Canadian Neutron Beam Centre and Comelius University (Slovakia); Katsaras, John [ORNL; Fragneto, Giovanna [Institut Laue-Langevin (ILL); Rheinstadter, Maikel C [McMaster University

    2012-01-01

    Lateral nanostructures in membranes, so-called rafts, are believed to strongly influence membrane properties and functions. The experimental observation of rafts has proven difficult as they are thought to be dynamic structures that likely fluctuate on nano- to microsecond time scales. Using neutron diffraction we present direct experimental evidence for the co-existence of gel and fluid lipid domains in a single-component phospholipid membrane made of DPPC as it undergoes its main phase transition. The coherence length of the neutron beam sets a lower limit for the size of structures that can be observed. Neutron coherence lengths between 30 and 242A used in this study were obtained by varying the incident neutron energy and the resolution of the neutron spectrometer. We observe Bragg peaks corresponding to co-existing nanometer sized structures, both in out-of-plane and in-plane scans, by tuning the neutron coherence length. During the main phase transition, instead of a continuous transition that shows a pseudo-critical behavior, we observe the co-existence of gel and fluid domains.

  4. Application of Phase Shifted, Laser Feedback Interferometry to Fluid Physics

    Science.gov (United States)

    Ovryn, Ben; Eppell, Steven J.; Andrews, James H.; Khaydarov, John

    1996-01-01

    We have combined the principles of phase-shifting interferometry (PSI) and laser-feedback interferometry (LFI) to produce a new instrument that can measure both optical path length (OPL) changes and discern sample reflectivity variations. In LFI, coherent feedback of the incident light either reflected directly from a surface or reflected after transmission through a region of interest will modulate the output intensity of the laser. LFI can yield a high signal-to-noise ratio even for low reflectivity samples. By combining PSI and LFI, we have produced a robust instrument, based upon a HeNe laser, with high dynamic range that can be used to measure either static (dc) or oscillatory changes along the optical path. As with other forms of interferometry, large changes in OPL require phase unwrapping. Conversely, small phase changes are limited by the fraction of a fringe that can be measured. We introduce the phase shifts with an electro-optic modulator (EOM) and use either the Carre or Hariharan algorithms to determine the phase and visibility. We have determined the accuracy and precision of our technique by measuring both the bending of a cantilevered piezoelectric bimorph and linear ramps to the EOM. Using PSI, sub-nanometer displacements can be measured. We have combined our interferometer with a commercial microscope and scanning piezoelectric stage and have measured the variation in OPL and visibility for drops of PDMS (silicone oil) on coated single crystal silicon. Our measurement of the static contact angle agrees with the value of 68 deg stated in the literature.

  5. Fast separation of triterpenoid saponins using supercritical fluid chromatography coupled with single quadrupole mass spectrometry.

    Science.gov (United States)

    Huang, Yang; Zhang, Tingting; Zhou, Haibo; Feng, Ying; Fan, Chunlin; Chen, Weijia; Crommen, Jacques; Jiang, Zhengjin

    2016-03-20

    Triterpenoid saponins (TSs) are the most important components of some traditional Chinese medicines (TCMs) and have exhibited valuable pharmacological properties. In this study, a rapid and efficient method was developed for the separation of kudinosides, stauntosides and ginsenosides using supercritical fluid chromatography coupled with single quadrupole mass spectrometry (SFC-MS). The separation conditions for the selected TSs were carefully optimized after the initial screening of eight stationary phases. The best compromise for all compounds in terms of chromatographic performance and MS sensitivity was obtained when water (5-10%) and formic acid (0.05%) were added to the supercritical carbon dioxide/MeOH mobile phase. Beside the composition of the mobile phase, the nature of the make-up solvent for interfacing SFC with MS was also evaluated. Compared to reversed phase liquid chromatography, the SFC approach showed higher resolution and shorter running time. The developed SFC-MS methods were successfully applied to the separation and identification of TSs present in Ilex latifolia Thunb., Panax quinquefolius L. and Panax ginseng C.A. Meyer. These results suggest that this SFC-MS approach could be employed as a useful tool for the quality assessment of natural products containing TSs as active components. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Particles at fluid-fluid interfaces: A new Navier-Stokes-Cahn-Hilliard surface- phase-field-crystal model.

    Science.gov (United States)

    Aland, Sebastian; Lowengrub, John; Voigt, Axel

    2012-10-01

    Colloid particles that are partially wetted by two immiscible fluids can become confined to fluid-fluid interfaces. At sufficiently high volume fractions, the colloids may jam and the interface may crystallize. The fluids together with the interfacial colloids form an emulsion with interesting material properties and offer an important route to new soft materials. A promising approach to simulate these emulsions was presented in Aland et al. [Phys. Fluids 23, 062103 (2011)], where a Navier-Stokes-Cahn-Hilliard model for the macroscopic two-phase fluid system was combined with a surface phase-field-crystal model for the microscopic colloidal particles along the interface. Unfortunately this model leads to spurious velocities which require very fine spatial and temporal resolutions to accurately and stably simulate. In this paper we develop an improved Navier-Stokes-Cahn-Hilliard-surface phase-field-crystal model based on the principles of mass conservation and thermodynamic consistency. To validate our approach, we derive a sharp interface model and show agreement with the improved diffuse interface model. Using simple flow configurations, we show that the new model has much better properties and does not lead to spurious velocities. Finally, we demonstrate the solid-like behavior of the crystallized interface by simulating the fall of a solid ball through a colloid-laden multiphase fluid.

  7. European developments in single phase turbulence for innovative reactors

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, F., E-mail: roelofs@nrg.eu [NRG, Petten (Netherlands); Rohde, M. [DUT, Delft (Netherlands); and others

    2011-07-01

    Thermal-hydraulics is recognized as a key scientific subject in the development of different innovative nuclear reactor systems. From the thermal-hydraulic point of view, different innovative reactors are mainly characterized by their coolants (gas, water, liquid metals and molten salt). They result in specific behavior of flow and heat transfer, which requires specific models and advanced analysis tools. However, many common thermal-hydraulic issues are identified among various innovative nuclear systems. In Europe, such cross-cutting thermal-hydraulics topics are the motivation for the THINS (Thermal-Hydraulics of Innovative Nuclear Systems) project which is sponsored by the European Commission from 2010 to 2014. This paper describes the ongoing developments in an important part of this project devoted to single phase turbulence issues. To this respect, the two main issues have been identified: Non-unity Prandtl number turbulence. In case of liquid metals, molten salts or supercritical fluids, the commonly applied constant turbulent Prandtl number concept is not applicable and robust engineering turbulence models are needed. This paper will report on the progress achieved with respect to the development and validation of turbulence models available in commonly used engineering tools. The paper also reports about the supporting experiments and direct numerical simulations; and, Temperature fluctuations possibly leading to thermal fatigue in innovative reactors. The status is described of a fundamental experiment dealing with the mixing of different density gases in a rectangular channel, an experiment in a more complex geometry of a small mixing plenum using a supercritical fluid, and direct numerical simulations of conjugate heat transfer on temperature fluctuations in liquid metal. (author)

  8. European developments in single phase turbulence for innovative reactors

    International Nuclear Information System (INIS)

    Roelofs, F.; Rohde, M.

    2011-01-01

    Thermal-hydraulics is recognized as a key scientific subject in the development of different innovative nuclear reactor systems. From the thermal-hydraulic point of view, different innovative reactors are mainly characterized by their coolants (gas, water, liquid metals and molten salt). They result in specific behavior of flow and heat transfer, which requires specific models and advanced analysis tools. However, many common thermal-hydraulic issues are identified among various innovative nuclear systems. In Europe, such cross-cutting thermal-hydraulics topics are the motivation for the THINS (Thermal-Hydraulics of Innovative Nuclear Systems) project which is sponsored by the European Commission from 2010 to 2014. This paper describes the ongoing developments in an important part of this project devoted to single phase turbulence issues. To this respect, the two main issues have been identified: Non-unity Prandtl number turbulence. In case of liquid metals, molten salts or supercritical fluids, the commonly applied constant turbulent Prandtl number concept is not applicable and robust engineering turbulence models are needed. This paper will report on the progress achieved with respect to the development and validation of turbulence models available in commonly used engineering tools. The paper also reports about the supporting experiments and direct numerical simulations; and, Temperature fluctuations possibly leading to thermal fatigue in innovative reactors. The status is described of a fundamental experiment dealing with the mixing of different density gases in a rectangular channel, an experiment in a more complex geometry of a small mixing plenum using a supercritical fluid, and direct numerical simulations of conjugate heat transfer on temperature fluctuations in liquid metal. (author)

  9. Single-superfield helical-phase inflation

    Energy Technology Data Exchange (ETDEWEB)

    Ketov, Sergei V., E-mail: ketov@tmu.ac.jp [Department of Physics, Tokyo Metropolitan University, Minami-ohsawa 1-1, Hachioji-shi, Tokyo 192-0397 (Japan); Kavli Institute for the Physics and Mathematics of the Universe (IPMU), The University of Tokyo, Chiba 277-8568 (Japan); Institute of Physics and Technology, Tomsk Polytechnic University, 30 Lenin Ave., Tomsk 634050 (Russian Federation); Terada, Takahiro, E-mail: takahiro@hep-th.phys.s.u-tokyo.ac.jp [Department of Physics, The University of Tokyo, Tokyo 113-0033 (Japan); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany)

    2016-01-10

    Large-field inflation in supergravity requires the approximate global symmetry needed to protect flatness of the scalar potential. In helical-phase inflation, the U(1) symmetry of the Kähler potential is assumed, the phase part of the complex scalar of a chiral superfield plays the role of inflaton, and the radial part is strongly stabilized. The original model of helical phase inflation, proposed by Li, Li and Nanopoulos (LLN), employs an extra (stabilizer) superfield. We propose a more economical new class of the helical phase inflationary models without a stabilizer superfield. As the specific examples, the quadratic, the natural, and the Starobinsky-type inflationary models are studied in our approach.

  10. Evaluating measurement uncertainty in fluid phase equilibrium calculations

    Science.gov (United States)

    van der Veen, Adriaan M. H.

    2018-04-01

    The evaluation of measurement uncertainty in accordance with the ‘Guide to the expression of uncertainty in measurement’ (GUM) has not yet become widespread in physical chemistry. With only the law of the propagation of uncertainty from the GUM, many of these uncertainty evaluations would be cumbersome, as models are often non-linear and require iterative calculations. The methods from GUM supplements 1 and 2 enable the propagation of uncertainties under most circumstances. Experimental data in physical chemistry are used, for example, to derive reference property data and support trade—all applications where measurement uncertainty plays an important role. This paper aims to outline how the methods for evaluating and propagating uncertainty can be applied to some specific cases with a wide impact: deriving reference data from vapour pressure data, a flash calculation, and the use of an equation-of-state to predict the properties of both phases in a vapour-liquid equilibrium. The three uncertainty evaluations demonstrate that the methods of GUM and its supplements are a versatile toolbox that enable us to evaluate the measurement uncertainty of physical chemical measurements, including the derivation of reference data, such as the equilibrium thermodynamical properties of fluids.

  11. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  12. Predicting phase shift effects for vibrating fluid-conveying pipes due to Coriolis forces and fluid pulsation

    DEFF Research Database (Denmark)

    Enz, Stephanie; Thomsen, Jon Juel

    2011-01-01

    to improve accuracy, precision, and robustness of CFMs. A simple mathematical model of a fluid-conveying pipe is formulated and the effect of pulsating fluid flow is analyzed using a multiple time scaling perturbation analysis. The results are simple analytical predictions for the transverse pipe...... and uncontrolled during CFM operation by feedback control. The analytical predictions offer an immediate insight into how fluid pulsation affects phase shift, which is a quantity measured by CFMs to estimate the mass flow, and lead to hypotheses for more complex geometries, i.e. industrial CFMs. The validity...... displacement and approximate axial shift in vibration phase. The analytical predictions are tested against pure numerical solution using representative examples, showing good agreement. Fluid pulsations are predicted not to influence CFM accuracy, since proper signal filtering is seen to allow...

  13. Dynamics of mineral crystallization from precipitated slab-derived fluid phase: first in situ synchrotron X-ray measurements

    Science.gov (United States)

    Malaspina, Nadia; Alvaro, Matteo; Campione, Marcello; Wilhelm, Heribert; Nestola, Fabrizio

    2015-03-01

    Remnants of the fluid phase at ultrahigh pressure (UHP) in subduction environments may be preserved as primary multiphase inclusions in UHP minerals. The mode of crystallization of daughter minerals during precipitation within the inclusion and/or the mechanism of interaction between the fluid at supercritical conditions and the host mineral are still poorly understood from a crystallographic point of view. A case study is represented by garnet-orthopyroxenites from the Maowu Ultramafic Complex (China) deriving from harzburgite precursors metasomatized at ~4 GPa, 750 °C by a silica- and incompatible trace element-rich fluid phase. This metasomatism produced poikilitic orthopyroxene and inclusion-rich garnet porphyroblasts. Solid multiphase primary inclusions in garnet display a size within a few tens of micrometres and negative crystal shapes. Infilling minerals (spinel: 10-20 vol%; amphibole, chlorite, talc, mica: 80-90 vol%) occur with constant volume proportions and derive from trapped solute-rich aqueous fluids. To constrain the possible mode of precipitation of daughter minerals, we performed for the first time a single-crystal X-ray diffraction experiment by synchrotron radiation at Diamond Light Source. In combination with electron probe microanalyses, this measurement allowed the unique identification of each mineral phase and reciprocal orientations. We demonstrated the epitaxial relationship between spinel and garnet and between some hydrous minerals. Such information is discussed in relation to the physico-chemical aspects of nucleation and growth, shedding light on the mode of mineral crystallization from a fluid phase trapped at supercritical conditions.

  14. Unexpectedly normal phase behavior of single homopolymer chains

    International Nuclear Information System (INIS)

    Paul, W.; Strauch, T.; Rampf, F.; Binder, K.

    2007-01-01

    Employing Monte Carlo simulations, we show that the topology of the phase diagram of a single flexible homopolymer chain changes in dependence on the range of an attractive square well interaction between the monomers. For a range of attraction larger than a critical value, the equilibrium phase diagram of the single polymer chain and the corresponding polymer solution phase diagram exhibit vapor (swollen coil, dilute solution), liquid (collapsed globule, dense solution), and solid phases. Otherwise, the liquid-vapor transition vanishes from the equilibrium phase diagram for both the single chain and the polymer solution. This change in topology of the phase diagram resembles the behavior known for colloidal dispersions. The interplay of enthalpy and conformational entropy in the polymer case thus can lead to the same topology of phase diagrams as the interplay of enthalpy and translational entropy in simple liquids

  15. Single-particle density matrix and superfluidity in the two-dimensional Bose Coulomb fluid

    International Nuclear Information System (INIS)

    Minguzzi, A.; Tosi, M.P.; Davoudi, B.

    2002-01-01

    A study by Magro and Ceperley [Phys. Rev. Lett. 73, 826 (1994)] has shown that the ground state of the two-dimensional fluid of charged bosons with logarithmic interactions is not Bose condensed, but exhibits algebraic off-diagonal order in the single-particle density matrix ρ(r). We use a hydrodynamic Hamiltonian expressed in terms of density and phase operators, in combination with an f-sum rule on the superfluid fraction, to reproduce these results and to extend the evaluation of the density matrix to finite temperature T. This approach allows us to treat the liquid as a superfluid in the absence of a condensate. The algebraic decay of the one-body density matrix is due to correlations between phase fluctuations, and we find that the exponent in the power law is determined by the superfluid density n s (T). We also find that the plasmon gap in the single-particle energy spectrum at long wavelengths decreases with increasing T and closes at the critical temperature for the onset of superfluidity

  16. Single-phase convective heat transfer in rod bundles

    International Nuclear Information System (INIS)

    Holloway, Mary V.; Beasley, Donald E.; Conner, Michael E.

    2008-01-01

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids

  17. Single-phase convective heat transfer in rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, Mary V. [Mechanical Engineering Department, United States Naval Academy, 590 Holloway Rd., Annapolis, MD 21402 (United States)], E-mail: holloway@usna.edu; Beasley, Donald E. [Mechanical Engineering Department, Clemson University, Clemson, SC 29634 (United States); Conner, Michael E. [Westinghouse Nuclear Fuel, 5801 Bluff Road, Columbia, SC 29250 (United States)

    2008-04-15

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids.

  18. Comparison of liquid and supercritical fluid chromatography mobile phases for enantioselective separations on polysaccharide stationary phases.

    Science.gov (United States)

    Khater, Syame; Lozac'h, Marie-Anne; Adam, Isabelle; Francotte, Eric; West, Caroline

    2016-10-07

    Analysis and production of enantiomerically pure compounds is a major topic of interest when active pharmaceutical ingredients are concerned. Enantioselective chromatography has become a favourite both at the analytical and preparative scales. High-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) are dominating the scene and are often seen as complementary techniques. Nowadays, for economic and ecologic reasons, SFC may be preferred over normal-phase HPLC (NPLC) as it allows significant reductions in solvent consumption. However, the transfer of NPLC methods to SFC is not always straightforward. In this study, we compare the retention of achiral molecules and separation of enantiomers under supercritical fluid (carbon dioxide with ethanol or isopropanol) and liquid normal-phase (heptane with ethanol or isopropanol) elution modes with polysaccharide stationary phases in order to explore the differences between the retention and enantioseparation properties between the two modes. Chemometric methods (namely quantitative structure-retention relationships and discriminant analysis) are employed to compare the results obtained on a large set of analytes (171 achiral probes and 97 racemates) and gain some understanding on the retention and separation mechanisms. The results indicate that, contrary to popular belief, carbon dioxide - solvent SFC mobile phases are often weaker eluents than liquid mobile phases. It appears that SFC and NPLC elution modes provide different retention mechanisms. While some enantioseparations are unaffected, facilitating the transfer between the two elution modes, other enantioseparations may be drastically different due to different types and strength of interactions contributing to enantioselectivity. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Timing, predictors, and progress of third space fluid accumulation during preliminary phase fluid resuscitation in adult patients with dengue.

    Science.gov (United States)

    Premaratna, R; Ragupathy, A; Miththinda, J K N D; de Silva, H J

    2013-07-01

    Fluid leakage remains the hallmark of dengue hemorrhagic fever (DHF). The applicability of currently recommended predictors of DHF for adults with dengue is questionable as these are based on studies conducted in children. One hundred and two adults with dengue were prospectively followed up to investigate whether home-based or hospital-based early phase fluid resuscitation has an impact on clinical and hematological parameters used for the diagnosis of early or critical phase fluid leakage. In the majority of subjects, third space fluid accumulation (TSFA) was detected on the fifth and sixth days of infection. The quantity and quality of fluids administered played no role in TSFA. A reduction in systolic blood pressure appeared to be more helpful than a reduction in pulse pressure in predicting fluid leakage. TSFA occurred with lower percentage rises in packed cell volume (PCV) than stated in the current recommendations. A rapid reduction in platelets, progressive reduction in white blood cells, percentage rises in Haemoglobin (Hb), and PCV, and rises in aspartate aminotransferase and alanine aminotransferase were observed in patients with TSFA and therefore with the development of severe illness. Clinicians should be aware of the limitations of currently recommended predictors of DHF in adult patients who are receiving fluid resuscitation. Copyright © 2013 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  20. Fluid Phase Separation (FPS) experiment for flight on a space shuttle Get Away Special (GAS) canister

    Science.gov (United States)

    Peters, Bruce; Wingo, Dennis; Bower, Mark; Amborski, Robert; Blount, Laura; Daniel, Alan; Hagood, Bob; Handley, James; Hediger, Donald; Jimmerson, Lisa

    1990-01-01

    The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid which will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on the Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS-42. The design and the production of a fluid phase separation experiment for rapid implementation at low cost is presented.

  1. Reliable Actuator for Cryo Propellant Fluid Control, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Fluid handling applications in cryogenic and extreme environments require reliable actuation technology that can handle extreme temperatures, mechanical bind-up from...

  2. Geometric analysis of the solutions of two-phase flows: two-fluid model

    International Nuclear Information System (INIS)

    Kestin, J.; Zeng, D.L.

    1984-01-01

    This report contains a lightly edited draft of a study of the two-fluid model in two-phase flow. The motivation for the study stems from the authors' conviction that the construction of a computer code for any model should be preceded by a geometrical analysis of the pattern of trajectories in the phase space appropriate for the model. Such a study greatly facilitates the understanding of the phenomenon of choking and anticipates the computational difficulties which arise from the existence of singularities. The report contains a derivation of the six conservation equations of the model which includes a consideration of the simplifications imposed on a one-dimensional treatment by the presence of boundary layers at the wall and between the phases. The model is restricted to one-dimensional adiabatic flows of a single substance present in two phases, but thermodynamic equilibrium between the phases is not assumed. The role of closure conditions is defined but no specific closure conditions, or explicit equations of state, are introduced

  3. Natural circulation in single-phase and two-phase flow

    International Nuclear Information System (INIS)

    Cheung, F.B.; El-Genk, M.S.

    1989-01-01

    Natural circulation usually arises in a closed loop between a heat source and a heat sink were the fluid motion is driven by density difference. It may also occur in enclosures or cavities where the flow is induced primarily by temperature or concentration gradients within the fluid. The subject has recently received special attention by the heat transfer and nuclear reactor safety communities because of it importance to the areas of energy extraction, decay, heat removal in nuclear reactors, solar and geothermal heating, and cooling of electronic equipment. Although many new results and physical insights have been gained of the various natural circulation phenomena, a number of critical issues remain unresolved. These include, for example, transition from laminar to turbulent flow, buoyancy-induced turbulent flow modeling, change of flow regimes, flow field visualization, variable property effects, and flow instability. This symposium volume contains papers presented in the Natural Circulation in Single-Phase and Two-Phase Flow session at the 1989 Winter Annual Meeting of ASME, by authors from different countries including the United States, Japan, Canada, and Brazil. The papers deal with experimental and theoretical studies as well as state-of-the-art reviews, covering a broad spectrum of topics in natural circulation including: variable-conductance thermosyphons, microelectronic chip cooling, natural circulation in anisotropic porous media and in cavities, heat transfer in flat plat solar collectors, shutdown heat removal in fast reactors, cooling of light-water and heavy-water reactors. The breadth of papers contained in this volume clearly reflect the importance of the current interest in natural circulation as a means for passive cooling and heating

  4. A Novel Single Phase Hybrid Switched Reluctance Motor Drive System

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni

    2011-01-01

    In this paper, a novel single phase hybrid switched reluctance motor(SRM) drive system is proposed. It integrated a single phase hybrid SRM and a novel single phase boost converter. This motor can reduce the number of phase switch. And the permanent magnet which is used in the motor can improve...... the performance and efficiency of SR motor. However, the inherent characteristic of this motor is that the negative torque is very sensitive with the excitation current near the turn-on angle. The slow excitation current limits the torque generation region and reduces the average torque. Therefore, a novel single...... phase boost converter is applied to improve the performance of this motor. It is easy to generate a double dclink voltage and dc-link voltage and switch both of them. The voltage of boost capacitor is self balance, so the protective circuit is not need to consider. The fast excitation mode helps hybrid...

  5. Wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes with surface and nonlocal effects

    Science.gov (United States)

    Zhen, Ya-Xin

    2017-02-01

    In this paper, the transverse wave propagation in fluid-conveying viscoelastic single-walled carbon nanotubes is investigated based on nonlocal elasticity theory with consideration of surface effect. The governing equation is formulated utilizing nonlocal Euler-Bernoulli beam theory and Kelvin-Voigt model. Explicit wave dispersion relation is developed and wave phase velocities and frequencies are obtained. The effect of the fluid flow velocity, structural damping, surface effect, small scale effects and tube diameter on the wave propagation properties are discussed with different wave numbers. The wave frequency increases with the increase of fluid flow velocity, but decreases with the increases of tube diameter and wave number. The effect of surface elasticity and residual surface tension is more significant for small wave number and tube diameter. For larger values of wave number and nonlocal parameters, the real part of frequency ratio raises.

  6. Thermal analysis of hybrid single-phase, two-phase and heat pump thermal control system (TCS) for future spacecraft

    International Nuclear Information System (INIS)

    Lee, S.H.; Mudawar, I.; Hasan, Mohammad M.

    2016-01-01

    Highlights: • Hybrid Thermal Control System (H-TCS) is proposed for future spacecraft. • Thermodynamic performance of H-TCS is examined for different space missions. • Operational modes including single-phase, two-phase and heat pump are explored. • R134a is deemed most appropriate working fluid. - Abstract: An urgent need presently exists to develop a new class of versatile spacecraft capable of conducting different types of missions and enduring varying gravitational and temperature environments, including Lunar, Martian and Near Earth Object (NEOs). This study concerns the spacecraft's Thermal Control System (TCS), which tackles heat acquisition, especially from crew and avionics, heat transport, and ultimate heat rejection by radiation. The primary goal of the study is to explore the design and thermal performance of a Hybrid Thermal Control System (H-TCS) that would satisfy the diverse thermal requirements of the different space missions. The H-TCS must endure both ‘cold’ and ‘hot’ environments, reduce weight and size, and enhance thermodynamic performance. Four different operational modes are considered: single-phase, two-phase, basic heat pump and heat pump with liquid-side, suction-side heat exchanger. A thermodynamic trade study is conducted for six different working fluids to assess important performance parameters including mass flow rate of the working fluid, maximum pressure, radiator area, compressor/pump work, and coefficient of performance (COP). R134a is determined to be most suitable based on its ability to provide a balanced compromise between reducing flow rate and maintaining low system pressure, and a moderate coefficient of performance (COP); this fluid is also both nontoxic and nonflammable, and features zero ozone depletion potential (ODP) and low global warming potential (GWP). It is shown how specific mission stages dictate which mode of operation is most suitable, and this information is used to size the radiator for the

  7. Principles of fluid management and stewardship in septic shock: it is time to consider the four D's and the four phases of fluid therapy.

    Science.gov (United States)

    Malbrain, Manu L N G; Van Regenmortel, Niels; Saugel, Bernd; De Tavernier, Brecht; Van Gaal, Pieter-Jan; Joannes-Boyau, Olivier; Teboul, Jean-Louis; Rice, Todd W; Mythen, Monty; Monnet, Xavier

    2018-05-22

    In patients with septic shock, the administration of fluids during initial hemodynamic resuscitation remains a major therapeutic challenge. We are faced with many open questions regarding the type, dose and timing of intravenous fluid administration. There are only four major indications for intravenous fluid administration: aside from resuscitation, intravenous fluids have many other uses including maintenance and replacement of total body water and electrolytes, as carriers for medications and for parenteral nutrition. In this paradigm-shifting review, we discuss different fluid management strategies including early adequate goal-directed fluid management, late conservative fluid management and late goal-directed fluid removal. In addition, we expand on the concept of the "four D's" of fluid therapy, namely drug, dosing, duration and de-escalation. During the treatment of patients with septic shock, four phases of fluid therapy should be considered in order to provide answers to four basic questions. These four phases are the resuscitation phase, the optimization phase, the stabilization phase and the evacuation phase. The four questions are "When to start intravenous fluids?", "When to stop intravenous fluids?", "When to start de-resuscitation or active fluid removal?" and finally "When to stop de-resuscitation?" In analogy to the way we handle antibiotics in critically ill patients, it is time for fluid stewardship.

  8. A facility for the experimental investigation of single substance two phase flow

    International Nuclear Information System (INIS)

    Maeder, P.F.; Dickinson, D.A.; Nikitopoulos, D.E.; DiPippo, R.

    1985-01-01

    The paper describes a research facility dedicated to single-substance two-phase flow. The working fluid is dichlorotetrafluoroethane (or refrigerant R-114), allowing both operation at manageable pressures, temperatures and flowrates, and application of results to practical situations through similarity. Operation is in the blowdown mode. The control and data acquisition systems are fully automated and computer controlled. A range of flow conditions from predominantly liquid flow to high velocity, high void fraction choked flow can be attained

  9. Invasion percolation of single component, multiphase fluids with lattice Boltzmann models

    International Nuclear Information System (INIS)

    Sukop, M.C.; Or, Dani

    2003-01-01

    Application of the lattice Boltzmann method (LBM) to invasion percolation of single component multiphase fluids in porous media offers an opportunity for more realistic modeling of the configurations and dynamics of liquid/vapor and liquid/solid interfaces. The complex geometry of connected paths in standard invasion percolation models arises solely from the spatial arrangement of simple elements on a lattice. In reality, fluid interfaces and connectivity in porous media are naturally controlled by the details of the pore geometry, its dynamic interaction with the fluid, and the ambient fluid potential. The multiphase LBM approach admits realistic pore geometry derived from imaging techniques and incorporation of realistic hydrodynamics into invasion percolation models

  10. Study of a new static mixer for two-phase and single-phase flows

    International Nuclear Information System (INIS)

    Foucrier, Michel

    1996-01-01

    The subject of this work is the study of OptimiX, a new static mixer, which is fully designed using an inverse method taking the final product features as input and based on the physical properties of the fluid to mix. The work began with the construction of an experimental loop which allowed us to qualify the mixer in two-phase and single-phase flow conditions. Next, a chemical method using a new test reaction and a micro-mixing model have been used to further characterise the mixer. This test reaction and the micro-mixing model have been developed by the 'Laboratoire des Sciences du Genie Chimique' of Nancy. The mixer OptimiX has proved to be an excellent device for both macro- and micro-mixing. The capability of this mixer to foster rapid reactions was also demonstrated. The well organised flow pattern of OptimiX, which results from its design, provides it with the unusual feature of being fully calculable. This work emphasizes the internal hydrodynamics of this mixer, justifies the universality of the design procedures, which validation is supported by the completed qualification work. (author) [fr

  11. Theory for added mass of a vibrating circular rod in a two-phase air-water fluid

    International Nuclear Information System (INIS)

    Kohgo, Osamu; Hara, Fumio

    1985-01-01

    It has been well known that there are added mass and attenuation effect due to surrounding fluid in a structure vibrating in the fluid, and those are different according to the density and viscosity of the fluid and the form of the structure. In this study, in order to clarify added mass, the model of the vapor-liquid two-phase fluid with discontinuous density distribution was made. That is, bubbles were assumed to be a bubble column without bending stiffness and mass, and potential analysis was applied to a two-dimensional fluid field composed of a round section beam and the bubble column, thus their relative motion was hydrodynamically analyzed, and the theory for evaluating added mass was developed. The added mass experimentally determined from the response gain of a single round section cantilever when it was oscillated steadily, uniformly and at random in the vapor-liquid two-phase fluid being stationary as a whole and the theoretical result were examined by comparison, and equivalent bubble diameter was considered, thereafter, the validity of the model was examined. (Kako, I.)

  12. A combined single-multiphase flow formulation of the premixing phase using the level set method

    International Nuclear Information System (INIS)

    Leskovar, M.; Marn, J.

    1999-01-01

    The premixing phase of a steam explosion covers the interaction of the melt jet or droplets with the water prior to any steam explosion occurring. To get a better insight of the hydrodynamic processes during the premixing phase beside hot premixing experiments, where the water evaporation is significant, also cold isothermal premixing experiments are performed. The specialty of isothermal premixing experiments is that three phases are involved: the water, the air and the spheres phase, but only the spheres phase mixes with the other two phases whereas the water and air phases do not mix and remain separated by a free surface. Our idea therefore was to treat the isothermal premixing process with a combined single-multiphase flow model. In this combined model the water and air phase are treated as a single phase with discontinuous phase properties at the water air interface, whereas the spheres are treated as usually with a multiphase flow model, where the spheres represent the dispersed phase and the common water-air phase represents the continuous phase. The common water-air phase was described with the front capturing method based on the level set formulation. In the level set formulation, the boundary of two-fluid interfaces is modeled as the zero set of a smooth signed normal distance function defined on the entire physical domain. The boundary is then updated by solving a nonlinear equation of the Hamilton-Jacobi type on the whole domain. With this single-multiphase flow model the Queos isothermal premixing Q08 has been simulated. A numerical analysis using different treatments of the water-air interface (level set, high-resolution and upwind) has been performed for the incompressible and compressible case and the results were compared to experimental measurements.(author)

  13. Diffusion of Supercritical Fluids through Single-Layer Nanoporous Solids: Theory and Molecular Simulations.

    Science.gov (United States)

    Oulebsir, Fouad; Vermorel, Romain; Galliero, Guillaume

    2018-01-16

    With the advent of graphene material, membranes based on single-layer nanoporous solids appear as promising devices for fluid separation, be it liquid or gaseous mixtures. The design of such architectured porous materials would greatly benefit from accurate models that can predict their transport and separation properties. More specifically, there is no universal understanding of how parameters such as temperature, fluid loading conditions, or the ratio of the pore size to the fluid molecular diameter influence the permeation process. In this study, we address the problem of pure supercritical fluids diffusing through simplified models of single-layer porous materials. Basically, we investigate a toy model that consists of a single-layer lattice of Lennard-Jones interaction sites with a slit gap of controllable width. We performed extensive equilibrium and biased molecular dynamics simulations to document the physical mechanisms involved at the molecular scale. We propose a general constitutive equation for the diffusional transport coefficient derived from classical statistical mechanics and kinetic theory, which can be further simplified in the ideal gas limit. This transport coefficient relates the molecular flux to the fluid density jump across the single-layer membrane. It is found to be proportional to the accessible surface porosity of the single-layer porous solid and to a thermodynamic factor accounting for the inhomogeneity of the fluid close to the pore entrance. Both quantities directly depend on the potential of mean force that results from molecular interactions between solid and fluid atoms. Comparisons with the simulations data show that the kinetic model captures how narrowing the pore size below the fluid molecular diameter lowers dramatically the value of the transport coefficient. Furthermore, we demonstrate that our general constitutive equation allows for a consistent interpretation of the intricate effects of temperature and fluid loading

  14. High Energy Single Frequency Resonant Amplifier, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  15. LENA Conversion Foils Using Single-Layer Graphene, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Our key innovation will be the use of single-layer graphene as LENA conversion foils, with appropriate microgrids and nanogrids to support the foils. Phase I...

  16. Non Invasive Instrumentation For Single Event Effects (NIISEE), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — On this Phase 1 project, Adventium will identify and address key hurdles to achieve Radiation Hardening by Software (RHS) for Single Event Effects (SEEs) for modern...

  17. Improvement of Torque Production in Single-Phase Induction Motors

    African Journals Online (AJOL)

    OLUWASOGO

    PID controller. Simulation results show the starting torque of the motor increased by 75% under the developed drive .... The model equations of the capacitor-run single phase induction .... process using the MATLAB pidtool command (Control.

  18. Load compensation for single phase system using series active filter ...

    African Journals Online (AJOL)

    Load compensation for single phase system using series active filter. ... KK Mishra, R Gupta ... load varies from time to time, the non linear load ranging from voltage source type harmonic load (VSHL) dominant to current source type harmonic ...

  19. Reliable Actuator for Cryo Propellant Fluid Control, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid handling applications require a reliable actuation technology that can handle very low temperatures. A novel EM hammer drive technology is proposed...

  20. Passive Devices for Advanced Fluid Management aboard Spacecraft, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Acute challenges are faced by the designers of fluid systems for spacecraft because of the persistently unfamiliar and unforgiving low-g environment. For example,...

  1. Dynamics Assessment of Advanced Single-Phase PLL Structures

    DEFF Research Database (Denmark)

    Golestan, Saeed; Monfarad, Mohammad; Freijedo, Francisco D.

    2013-01-01

    Recently, several advanced phase locked loop (PLL) techniques have been proposed for single-phase applications. Among these, the Park-PLL, and the second order generalized integrator (SOGI) based PLL are very attractive, owing to their simple digital implementation, low computational burden...

  2. Comparative Study of Phase Transformation in Single-Crystal Germanium during Single and Cyclic Nanoindentation

    Directory of Open Access Journals (Sweden)

    Koji Kosai

    2017-11-01

    Full Text Available Single-crystal germanium is a semiconductor material which shows complicated phase transformation under high pressure. In this study, new insight into the phase transformation of diamond-cubic germanium (dc-Ge was attempted by controlled cyclic nanoindentation combined with Raman spectroscopic analysis. Phase transformation from dc-Ge to rhombohedral phase (r8-Ge was experimentally confirmed for both single and cyclic nanoindentation under high loading/unloading rates. However, compared to single indentation, double cyclic indentation with a low holding load between the cycles caused more frequent phase transformation events. Double cyclic indentation caused more stress in Ge than single indentation and increased the possibility of phase transformation. With increase in the holding load, the number of phase transformation events decreased and finally became less than that under single indentation. This phenomenon was possibly caused by defect nucleation and shear accumulation during the holding process, which were promoted by a high holding load. The defect nucleation suppressed the phase transformation from dc-Ge to r8-Ge, and shear accumulation led to another phase transformation pathway, respectively. A high holding load promoted these two phenomena, and thus decreased the possibility of phase transformation from dc-Ge to r8-Ge.

  3. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    DR OKE

    of the wavelet modulated (WM) scheme is that a single synthesis function, derived ... a single-phase H-bridge voltage-source (VS) inverter using MATLAB simulations. ... reconstruction process has been suggested to device a new class of ...

  4. Unconventional phase transitions in a constrained single polymer chain

    International Nuclear Information System (INIS)

    Klushin, L I; Skvortsov, A M

    2011-01-01

    Phase transitions were recognized among the most fascinating phenomena in physics. Exactly solved models are especially important in the theory of phase transitions. A number of exactly solved models of phase transitions in a single polymer chain are discussed in this review. These are three models demonstrating the second order phase transitions with some unusual features: two-dimensional model of β-structure formation, the model of coil–globule transition and adsorption of a polymer chain grafted on the solid surface. We also discuss models with first order phase transitions in a single macromolecule which admit not only exact analytical solutions for the partition function with explicit finite-size effects but also the non-equilibrium free energy as a function of the order parameter (Landau function) in closed analytical form. One of them is a model of mechanical desorption of a macromolecule, which demonstrates an unusual first order phase transition with phase coexistence within a single chain. Features of first and second order transitions become mixed here due to phase coexistence which is not accompanied by additional interfacial free energy. Apart from that, there exist several single-chain models belonging to the same class (adsorption of a polymer chain tethered near the solid surface or liquid–liquid interface, and escape transition upon compressing a polymer between small pistons) that represent examples of a highly unconventional first order phase transition with several inter-related unusual features: no simultaneous phase coexistence, and hence no phase boundary, non-concave thermodynamic potential and non-equivalence of conjugate ensembles. An analysis of complex zeros of partition functions upon approaching the thermodynamic limit is presented for models with and without phase coexistence. (topical review)

  5. Thermo-fluid dynamics of two-phase flow

    CERN Document Server

    Ishii, Mamoru; Ishii, Mamoru; Ishii, M

    2006-01-01

    Provides a very systematic treatment of two phase flow problems from a theoretical perspectiveProvides an easy to follow treatment of modeling and code devlopemnt of two phase flow related phenomenaCovers new results of two phase flow research such as coverage of fuel cells technology.

  6. Smoothed particle hydrodynamics model for phase separating fluid mixtures. I. General equations

    NARCIS (Netherlands)

    Thieulot, C; Janssen, LPBM; Espanol, P

    We present a thermodynamically consistent discrete fluid particle model for the simulation of a recently proposed set of hydrodynamic equations for a phase separating van der Waals fluid mixture [P. Espanol and C.A.P. Thieulot, J. Chem. Phys. 118, 9109 (2003)]. The discrete model is formulated by

  7. Nonlinear free vibration of single walled Carbone NanoTubes conveying fluid

    Directory of Open Access Journals (Sweden)

    Azrar A.

    2014-04-01

    Full Text Available Nonlinear free vibration of single-walled carbon nanotubes (CNTs conveying fluid are modeled and numerically simulated based on von Kármán geometric nonlinearity and Eringen’s nonlocal elasticity theory. The CNTs are modelled as nanobeams where the effects of transverse shear deformation and rotary inertia are considered within the framework of Timoshenko beam theory. The governing equations and boundary conditions are derived using the Hamilton’s principle and the nonlinear equation of motion is solved by the Galerkin’s method. The small scale parameter and the fluid-tube interaction effects on the dynamic behaviours of the CNT-fluid system as well as the instabilities induced by the fluid-velocity can be investigated. The critical fluid-velocity and frequency-amplitude relationships as well as the flutter and divergence instability types and the associated time responses are obtained based on the presented methodological approach.

  8. Single-phase DECT with VNCT compared with three-phase CTU in patients with haematuria

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung Jae; Park, Byung Kwan; Kim, Chan Kyo [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea, Republic of)

    2016-10-15

    To retrospectively evaluate the diagnostic performance of single-phase dual-energy CT (DECT) with virtual non-contrast CT (VNCT) compared with three-phase CT urography (CTU) in patients with haematuria. A total of 296 patients underwent three-phase CTU (NCT at 120 kVp; nephrographic phase and excretory phase DECTs at 140 kVp and 80 kVp) owing to haematuria. Diagnostic performances of CT scans were compared for detecting urothelial tumours and urinary stones. Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU Dose-length product (DLP) was compared in relation to single-phase DECT and three-phase CTU. Sensitivity and specificity for tumour were 95 % (19/20) and 98.9 % (273/276) on CTU, 95 % (19/20) and 98.2 % (271/276) on nephrographic phase DECT, and 90 % (18/20) and 98.2 % (271/276) on excretory phase DECT (P > 0.1). Of the 148 stones detected on NCT, 108 (73 %) and 100 (67.6 %) were detected on nephrographic phase and excretory phase VNCTs, respectively. The mean size of stones undetected on nephrographic and excretory VNCTs was measured as 1.5 ± 0.5 mm and 1.6 ± 0.6 mm, respectively. The mean DLPs of three-phase CTU, nephrographic phase DECT and excretory phase DECT were 1076 ± 248 mGy . cm, 410 ± 98 mGy . cm, and 360 ± 87 mGy . cm, respectively (P < 0.001). Single-phase DECT has a potential to replace three-phase CTU for detecting tumours with a lower radiation dose. (orig.)

  9. Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids

    OpenAIRE

    Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, P. (Petra); Filip, P. (Petr); Vesel, A.

    2011-01-01

    The aim of this paper is to document suitability of plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids. Surface-modified carbonyl iron particles were prepared via their exposure to 50% argon and 50% octafluorocyclobutane plasma. The X-ray photoelectron spectroscopy was used for analysis of chemical bonding states in the surface layer. Plasma-treated particles were adopted for a dispersed phase in magnetorheological (MR) fluids, and the MR behaviour was in...

  10. Fluid and mass transport in a single lymphatic blood vessel

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1987-08-01

    The problem considers the single blood vessel model in pulmonary circulation in the presence of gravitation and mass transfer. The tissue surrounding the blood vessel is modelled as a permeable medium distinct from the blood vessel which is a normal free space. On the assumption that the mass concentration varies slowly at the interface between the blood vessel and the tissue, the problem is tackled by asymptotic approximation. A crucial point of the analysis is the dependence of the flow variables on the permeability K of the tissue in a completely arbitrary manner. A primary conjecture of the study is the intimacy of the pathological pulmonary edema and the parameter K. (author). 4 refs

  11. Development of a single-phase thermosiphon for cold collection and storage of radiative cooling

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dongliang; Martini, Christine Elizabeth; Jiang, Siyu; Ma, Yaoguang; Zhai, Yao; Tan, Gang; Yin, Xiaobo; Yang, Ronggui

    2017-11-01

    A single-phase thermosiphon is developed for cold collection and storage of radiative cooling. Compared to the conventional nocturnal radiative cooling systems that use an electric pump to drive the heat transfer fluid, the proposed single-phase thermosiphon uses the buoyancy force to drive heat transfer fluid. This solution does not require electricity, therefore improving the net gain of the radiative cooling system. A single-phase thermosiphon was built, which consists of a flat panel, a cold collection tank, a water return tube, and a water distribution tank. Considering that outdoor radiative cooling flux is constantly changing (i.e. uncontrollable), an indoor testing facility was developed to provide a controllable cooling flux (comparable to a radiative cooling flux of 100 W/m2) for the evaluation of thermosiphon performance. The testing apparatus is a chilled aluminum flat plate that has a controlled air gap separation relative to the flat panel surface of the thermosiphon to emulate radiative cooling. With an average of 105 W/m2 cooling flux, the 18 liters of water in the thermosiphon was cooled to an average temperature of 12.5 degrees C from an initial temperature of 22.2 degrees C in 2 h, with a cold collection efficiency of 96.8%. The results obtained have demonstrated the feasibility of using a single-phase thermosiphon for cold collection and storage of radiative cooling. Additionally, the effects of the thermosiphon operation conditions, such as tilt angle of the flat panel, initial water temperature, and cooling energy flux, on the performance have been experimentally investigated. Modular design of the single-phase thermosiphon gives flexibility for its scalability. A radiative cooling system with multiple thermosiphon modules is expected to play an important role in cooling buildings and power plant condensers.

  12. Fluid-elastic force measurements acting on a tube bundle in two-phase cross flow

    International Nuclear Information System (INIS)

    Inada, Fumio; Kawamura, Koji; Yasuo, Akira

    1996-01-01

    Fluid-elastic force acting on a square tube bundle of P/D = 1.47 in air-water two-phase cross flow was measured to investigate the characteristics and to clarify whether the fluid elastic vibration characteristics could be expressed using two-phase mixture characteristics. Measured fluid elastic forces were separated into fluid-elastic force coefficients such as added mass, added stiffness, and added damping coefficient. The added damping coefficient was separated into a two-phase damping and a flow-dependent component as in previous research (Carlucci, 1981 and 1983; Pettigrew, 1994). These coefficients were nondimensionalized with two-phase mixture characteristics such as void fraction, mixture density and mixture velocity, which were obtained using the drift-flux model with consideration given to the model. The result was compared with the result obtained with the homogeneous model. It was found that fluid-elastic force coefficients could be expressed with two-phase flow mixture characteristics very well in the experimental result, and that better result can be derived using the slip model as compared to the homogeneous model. Added two-phase flow, which could be expressed as a function of void fraction, where two-phase damping was nondimensionalized with the relative velocity between the gas and liquid phases used as a reference velocity. Using these, the added stiffness coefficient and flow-dependent component of damping could be expressed very well as a function of nondimensional mixture velocity

  13. Deterministic nonlinear phase gates induced by a single qubit

    Science.gov (United States)

    Park, Kimin; Marek, Petr; Filip, Radim

    2018-05-01

    We propose deterministic realizations of nonlinear phase gates by repeating a finite sequence of non-commuting Rabi interactions between a harmonic oscillator and only a single two-level ancillary qubit. We show explicitly that the key nonclassical features of the ideal cubic phase gate and the quartic phase gate are generated in the harmonic oscillator faithfully by our method. We numerically analyzed the performance of our scheme under realistic imperfections of the oscillator and the two-level system. The methodology is extended further to higher-order nonlinear phase gates. This theoretical proposal completes the set of operations required for continuous-variable quantum computation.

  14. Factors that affect the calibration of turbines in single-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Piper, T. C.

    1977-05-01

    Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated.

  15. Factors that affect the calibration of turbines in single-phase flow

    International Nuclear Information System (INIS)

    Piper, T.C.

    1977-05-01

    Basic turbine operation in single-phase flow is related. Causes and relative magnitudes of retarding torque are given for two sizes of turbines when used for water flow measurement. An equation for slip caused by retarding torques is given. Evaluation of turbine slip behavior at the turbine low flow region shows that bearing retarding torques, change in flow patterns, or other effects can predominate in the relatively large changes in the calibration ''constant'' that occurs there. Fluid lubricity is singled out as an important fluid property in certain types of bearings and flow. Temperature induced changes in turbine size are shown to cause calibration changes if a turbine is used at a temperature significantly different than that at which it was calibrated

  16. Study of Mururoa's basaltic massif alteration (French Polynesia): solid and fluid phases analysis and thermodynamical modeling

    International Nuclear Information System (INIS)

    Destrigneville, Christine

    1991-01-01

    The alteration processes occurring in the volcanics of Mururoa have been studied using petrological data on secondary minerals, chemical analyses of the interstitial fluids and isotopic analyses on both minerals and fluids. Chemical and isotopic exchanges were first modelled, then thermodynamical modeling characterized the chemical evolution during the alteration of the secondary assemblage and of the fluid. The main secondary sequences which have been observed in Mururoa volcanics result from the alteration occurring during the lavas setting. Two different processes have been evidenced. The first one is the deuteric alteration with the CO_2-rich magmatic fluid exsolved from the magma and trapped in the vesicles and the olivine microcracks of the lava intrusions. This alteration in a closed system is dominated by the solid phases when the CO_2 molar fraction in the fluid is higher than 0.25. The second process is the alteration of the lavas by seawater or a meteoric fluid. The basaltic flows present alteration assemblages composed of clay minerals and zeolites whose chemical composition has been forced by the fluid composition. Shallowness emissions of lavas result in completely argillized levels. The present interstitial fluids chemistry result from the percolation of seawater in the volcano. In the argillized levels the fluids have interacted with the clay minerals and their chemical compositions have been modified. The important chemical changes in the present interstitial fluids show that the present alteration in the volcano is higher than the fluids circulation. (author) [fr

  17. Predicting phase shift of elastic waves in pipes due to fluid flow and imperfections

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Dahl, Jonas; Fuglede, Niels

    2009-01-01

    . This is relevant for understanding wave propagation in elastic media in general, and for the design and trouble-shooting of phase-shift measuring devices such as Coriolis mass flowmeters in particular. A multiple time scaling perturbation analysis is employed for a simple model of a fluid-conveying pipe......Flexural vibrations of a fluid-conveying pipe is investigated, with special consideration to the spatial shift in phase caused by fluid flow and various imperfections, e.g., non-ideal supports, non-uniform stiffness or mass, non-proportional damping, weak nonlinearity, and flow pulsation...

  18. Hydrodynamics of single- and two-phase flow in inclined rod arrays

    International Nuclear Information System (INIS)

    Ebeling-Koning, D.B.; Todreas, N.E.

    1983-09-01

    Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, and bubble distributions were measured in square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase incline flow a new flow separation phenomena was observed and modeled. A two-region liquid velocity model is developed to explain the experimentally observed phenomena. Fundamental data for bubbles rising in rod arrays were also taken

  19. Micro-analysis of plaque fluid from single-site fasted plaque

    International Nuclear Information System (INIS)

    Vogel, G.L.; Carey, C.M.; Chow, L.C.; Tatevossian, A.

    1990-01-01

    Despite the site-specific nature of caries, nearly all data on the concentration of ions relevant to the level of saturation of plaque fluid with respect to calcium phosphate minerals or enamel are from studies that used pooled samples. A procedure is described for the collection and analysis of inorganic ions relevant to these saturation levels in plaque fluid samples collected from a single surface on a single tooth. Various methods for examining data obtained by this procedure are described, and a mathematical procedure employing potential plots is recommended

  20. Are separate-phase thermal-hydraulic models better than mixture-fluid approaches? It depends. Rather not

    International Nuclear Information System (INIS)

    Hoeld, A.

    2004-01-01

    The thermal-hydraulic theory of single- and especially two-phase flow systems used for plant transient analysis is dominated by separate-phase models. The corresponding mostly very comprehensive codes (TRAC, RELAP, CATHARE, ATHLET etc.) are looked as to be by far more efficient than a 3 eq. mixture-fluid approach and code also if they show deficiencies in describing flow situations within inner loops as for example the distribution into parallel channels (and thus the simulation of 3D thermal-hydraulic phenomena). This may be justified if comparing them to the very simple 'homogeneous equilibrium models (HEM)', but not if looking to the more refined non-homogeneous 'separate-region' mixture-fluid approaches based on appropriate drift-flux correlation packages which can have, on the contrary, enormous advantages with respect to such separate-phase models. Especially if comparing the basic (and starting) eqs. of such theoretical models of both types the differences are remarkable. Single-phase and mixture-fluid models start from genuine conservation eqs. for mass, energy and momentum, demanding (in case of two-phase flow) additionally an adequate drift flux package (in order to get a relation for a fourth independent variable), a heat transfer coefficients package (over the whole range of the possible fields of application) and correlations for single- and two-phase friction. The other types of models are looking at each phase separately with corresponding 'field' eqs. for each phase, connected by exchange (=closure) terms which substitute the classical constitutive packages for drift, heat transfer and friction. That the drift-flux, heat transfer into a coolant channel and friction along a wall and between the phases is described better by a separate-phase approach is at least doubtful. The corresponding mixture-fluid correlations are based over a wide range on a treasure of experience and measurements, their pseudo-stationary treatment can (due to their small time

  1. Single phase inverter for a three phase power generation and distribution system

    Science.gov (United States)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  2. The Single-Phase ProtoDUNE Technical Design Report

    Energy Technology Data Exchange (ETDEWEB)

    Abi, B. [Univ. of Padova (Italy); et al.

    2017-06-21

    ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single-phase LArTPC detector to be built to date. It's technical design is given in this report.

  3. 30 CFR 77.806 - Connection of single-phase loads.

    Science.gov (United States)

    2010-07-01

    ... COAL MINES Surface High-Voltage Distribution § 77.806 Connection of single-phase loads. Single-phase loads, such as transformer primaries, shall be connected phase to phase in resistance grounded systems. ...

  4. 30 CFR 77.905 - Connection of single-phase loads.

    Science.gov (United States)

    2010-07-01

    ... COAL MINES Low- and Medium-Voltage Alternating Current Circuits § 77.905 Connection of single-phase loads. Single-phase loads shall be connected phase-to-phase in resistance grounded systems. ...

  5. Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC.

    Directory of Open Access Journals (Sweden)

    Zachary F Phillips

    Full Text Available We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC, is a single-shot variant of Differential Phase Contrast (DPC, which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps for various in vitro cell samples and c. elegans in a micro-fluidic channel.

  6. Study of the hard-disk system at high densities: the fluid-hexatic phase transition.

    Science.gov (United States)

    Mier-Y-Terán, Luis; Machorro-Martínez, Brian Ignacio; Chapela, Gustavo A; Del Río, Fernando

    2018-06-21

    Integral equations of uniform fluids have been considered unable to predict any characteristic feature of the fluid-solid phase transition, including the shoulder that arises in the second peak of the fluid-phase radial distribution function, RDF, of hard-core systems obtained by computer simulations, at fluid densities very close to the structural two-step phase transition. This reasoning is based on the results of traditional integral approximations, like Percus-Yevick, PY, which does not show such a shoulder in hard-core systems, neither in two nor three dimensions. In this work, we present results of three Ansätze, based on the PY theory, that were proposed to remedy the lack of PY analytical solutions in two dimensions. This comparative study shows that one of those Ansätze does develop a shoulder in the second peak of the RDF at densities very close to the phase transition, qualitatively describing this feature. Since the shoulder grows into a peak at still higher densities, this integral equation approach predicts the appearance of an orientational order characteristic of the hexatic phase in a continuous fluid-hexatic phase transition.

  7. Phase shift effects for fluid conveying pipes with non-ideal supports

    DEFF Research Database (Denmark)

    Dahl, Jonas; Thomsen, Jon Juel

    2008-01-01

    Vibrations of a fluid-conveying pipe with non-ideal supports are investigated with respect to phase shift effects. A numerical Galerkin approach is developed for this general problem, and the use of it exemplified with a investigation of phase shift effects from rotational damping at supports...

  8. A fluid biopsy as investigating technology for the fluid phase of solid tumors

    Science.gov (United States)

    Kuhn, Peter; Bethel, Kelly

    2012-02-01

    , which has shown predictive utility in several cancer types—the blurry outlines of things to come began to coalesce. The field of CTC research is in its adolescence; enumeration and characterization research effort is methodologically varied, vigorously individuated and rich in innovation. The high definition CTC (HD-CTC) assay described herein and applied to several currently relevant research questions about cancer spread represents a new measure of an internal biologic process that will hopefully lead to great advancements in cancer medicine. First, the paper entitled 'Fluid biopsy in patients with metastatic prostate, pancreatic and breast cancers' by Marrinucci et al, represents the initial technical and clinical validation of an enrichment-free assay and demonstrates our ability to identify significant numbers of HD-CTCs in a majority of patients with prostate, breast and pancreatic cancers. It demonstrates very high rates of detection (>50%) in breast, prostate and pancreatic cancer patients with no CTCs found in normal control subjects. The assay detects significantly higher numbers of CTCs than the FDA-approved Cellsearch® assay and shows the presence of clusters of CTCs in many patients. The nature of the clusters is further evaluated in 'Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors' by Cho et al, wherein CTC aggregates are identified in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung (NSCLC), 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors (NBD). Cells contained in CTC aggregates had less area and length, on average, than single CTCs. The nuclear to cytoplasmic (N/C) ratio between single CTCs and CTC aggregates was similar. To assist with translating into patients the substantial cell biology work done using cell line cells instead of human tumor tissue, the paper entitled 'Cytometric

  9. Investigation of effect of single phase electrical faults at LOFT

    International Nuclear Information System (INIS)

    Yeates, J.A.

    1978-01-01

    This LTR presents the general basic engineering facts related to an open phase fault in a three phase power system commonly referred to as a single phase condition. It describes the probable results to electrical motors and describes the LOFT system design factors which minimize the likelihood of such a fault occurring at LOFT. It recognizes that the hazard of such a fault is a realistic threat and notes the types of relays designed to provide protection. Recommendations are made to perform a detailed engineering study to determine the most advantageous protective relay design, and to implement such a design by installation of the necessary devices and controls

  10. Ultrafast electric phase control of a single exciton qubit

    Science.gov (United States)

    Widhalm, Alex; Mukherjee, Amlan; Krehs, Sebastian; Sharma, Nandlal; Kölling, Peter; Thiede, Andreas; Reuter, Dirk; Förstner, Jens; Zrenner, Artur

    2018-03-01

    We report on the coherent phase manipulation of quantum dot excitons by electric means. For our experiments, we use a low capacitance single quantum dot photodiode which is electrically controlled by a custom designed SiGe:C BiCMOS chip. The phase manipulation is performed and quantified in a Ramsey experiment, where ultrafast transient detuning of the exciton energy is performed synchronous to double pulse π/2 ps laser excitation. We are able to demonstrate electrically controlled phase manipulations with magnitudes up to 3π within 100 ps which is below the dephasing time of the quantum dot exciton.

  11. Simultaneous analysis for water- and fat-soluble vitamins by a novel single chromatography technique unifying supercritical fluid chromatography and liquid chromatography.

    Science.gov (United States)

    Taguchi, Kaori; Fukusaki, Eiichiro; Bamba, Takeshi

    2014-10-03

    Chromatography techniques usually use a single state in the mobile phase, such as liquid, gas, or supercritical fluid. Chromatographers manage one of these techniques for their purpose but are sometimes required to use multiple methods, or even worse, multiple techniques when the target compounds have a wide range of chemical properties. To overcome this challenge, we developed a single method covering a diverse compound range by means of a "unified" chromatography which completely bridges supercritical fluid chromatography and liquid chromatography. In our method, the phase state was continuously changed in the following order; supercritical, subcritical and liquid. Moreover, the gradient of the mobile phase starting at almost 100% CO2 was replaced with 100% methanol at the end completely. As a result, this approach achieved further extension of the polarity range of the mobile phase in a single run, and successfully enabled the simultaneous analysis of fat- and water-soluble vitamins with a wide logP range of -2.11 to 10.12. Furthermore, the 17 vitamins were exceptionally separated in 4min. Our results indicated that the use of dense CO2 and the replacement of CO2 by methanol are practical approaches in unified chromatography covering diverse compounds. Additionally, this is a first report to apply the novel approach to unified chromatography, and can open another door for diverse compound analysis in a single chromatographic technique with single injection, single column and single system. Copyright © 2014. Published by Elsevier B.V.

  12. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-[var epsilon] model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.

  13. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems

    International Nuclear Information System (INIS)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-var-epsilon model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results

  14. A Transformer-less Single Phase Inverter For photovoltaic Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Alizadeh, Ebrahim; Qu, Ying

    2017-01-01

    A single phase transformer-less inverter is introduced in this paper. The negative polarities of the input voltage and output terminal have common ground. Therefore, the leakage current problem that is common in PV systems is eliminated naturally. In addition, the proposed inverter has fewer comp...

  15. experimental implementation of single-phase, three-level, sinusoidal

    African Journals Online (AJOL)

    Page 1 ... of many multilevel inverter configurations. This paper presents an experimental report of a simplified topology for single-phase, SPWM, three-level voltage source inverter wit R-L load. To keep the power circuit ... employed in many industrial applications such as variable speed drives, uninterruptible power sup-.

  16. An Asymmetrical Space Vector Method for Single Phase Induction Motor

    DEFF Research Database (Denmark)

    Cui, Yuanhai; Blaabjerg, Frede; Andersen, Gert Karmisholt

    2002-01-01

    Single phase induction motors are the workhorses in low-power applications in the world, and also the variable speed is necessary. Normally it is achieved either by the mechanical method or by controlling the capacitor connected with the auxiliary winding. Any above method has some drawback which...

  17. Single-phase high-entropy alloys. An overview

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, Roksolana; Steurer, Walter [ETH Zurich (Switzerland). Lab. of Crystallography; Sologubenko, Alla [ETH Zurich (Switzerland). Lab. of Nanotechnology

    2015-02-01

    The term 'high-entropy alloys (HEAs)' first appeared about 10 years ago defining alloys composed of n=5-13 principal elements with concentrations of approximately 100/n at.% each. Since then many equiatomic (or near equiatomic) single- and multi-phase multicomponent alloys were developed, which are reported for a combination of tunable properties: high hardness, strength and ductility, oxidation and wear resistance, magnetism, etc. In our paper, we focus on probably single-phase HEAs (solid solutions) out of all HEAs studied so far, discuss ways of their prediction, mechanical properties. In contrast to classical multielement/multiphase alloys, only single-phase multielement alloys (solid solutions) represent the basic concept underlying HEAs as mixing-entropy stabilized homogenous materials. The literature overview is complemented by own studies demonstrating that the alloys CrFeCoNi, CrFeCoNiAl{sub 0.3} and PdFeCoNi homogenized at 1300 and 1100 C, respectively, for 1 week are not single-phase HEAs, but a coherent mixture of two solid solutions.

  18. Solar-Based Boost Differential Single Phase Inverter | Eya | Nigerian ...

    African Journals Online (AJOL)

    Solar-Based Boost Differential Single Phase Inverter. ... Solar-based boost differential inverter is reduced down to 22.37% in closed loop system with the aid of Proportional –integral-Differential (PID) ... The dc power source is photovoltaic cell.

  19. A single phase photovoltaic inverter control for grid connected system

    Indian Academy of Sciences (India)

    This paper presents a control scheme for single phase grid connected photovoltaic (PV) system operating under both grid connected and isolated grid mode. The control techniques include voltage and current control of grid-tie PV inverter. During grid connected mode, grid controls the amplitude and frequency of the PV ...

  20. MOLECULAR SIMULATION OF PHASE EQUILIBRIA FOR COMPLEX FLUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Athanassios Z. Panagiotopoulos

    2009-09-09

    The general area of this project was the development and application of novel molecular simulation methods for prediction of thermodynamic and structural properties of complex polymeric, surfactant and ionic fluids. Over this project period, we have made considerable progress in developing novel algorithms to meet the computational challenges presented by the strong or long-range interactions in these systems and have generated data for well-defined mod-els that can be used to test theories and compare to experimental data. Overall, 42 archival papers and many invited and contributed presentations and lectures have been based on work supported by this project. 6 PhD, 1 M.S. and 2 postdoctoral students have been associated with this work, as listed in the body of the report.

  1. Molecular Simulation Of Phase Equilibria For Complex Fluids

    International Nuclear Information System (INIS)

    Panagiotopoulos, Athanassios Z.

    2009-01-01

    The general area of this project was the development and application of novel molecular simulation methods for prediction of thermodynamic and structural properties of complex polymeric, surfactant and ionic fluids. Over this project period, we have made considerable progress in developing novel algorithms to meet the computational challenges presented by the strong or long-range interactions in these systems and have generated data for well-defined mod-els that can be used to test theories and compare to experimental data. Overall, 42 archival papers and many invited and contributed presentations and lectures have been based on work supported by this project. 6 PhD, 1 M.S. and 2 postdoctoral students have been associated with this work, as listed in the body of the report.

  2. Phase portrait methods for verifying fluid dynamic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, H.B.

    1989-01-01

    As computing resources become more powerful and accessible, engineers more frequently face the difficult and challenging engineering problem of accurately simulating nonlinear dynamic phenomena. Although mathematical models are usually available, in the form of initial value problems for differential equations, the behavior of the solutions of nonlinear models is often poorly understood. A notable example is fluid dynamics: while the Navier-Stokes equations are believed to correctly describe turbulent flow, no exact mathematical solution of these equations in the turbulent regime is known. Differential equations can of course be solved numerically, but how are we to assess numerical solutions of complex phenomena without some understanding of the mathematical problem and its solutions to guide us

  3. Scrutinization of thermal radiation, viscous dissipation and Joule heating effects on Marangoni convective two-phase flow of Casson fluid with fluid-particle suspension

    Science.gov (United States)

    Mahanthesh, B.; Gireesha, B. J.

    2018-03-01

    The impact of Marangoni convection on dusty Casson fluid boundary layer flow with Joule heating and viscous dissipation aspects is addressed. The surface tension is assumed to vary linearly with temperature. Physical aspects of magnetohydrodynamics and thermal radiation are also accounted. The governing problem is modelled under boundary layer approximations for fluid phase and dust particle phase and then Runge-Kutta-Fehlberg method based numeric solutions are established. The momentum and heat transport mechanisms are focused on the result of distinct governing parameters. The Nusselt number is also calculated. It is established that the rate of heat transfer can be enhanced by suspending dust particles in the base fluid. The temperature field of fluid phase and temperature of dust phase are quite reverse for thermal dust parameter. The radiative heat, viscous dissipation and Joule heating aspects are constructive for thermal fields of fluid and dust phases. The velocity of dusty Casson fluid dominates the velocity of dusty fluid while this trend is opposite in the case of temperature. Moreover qualitative behaviour of fluid phase and dust phase temperature/velocity are similar.

  4. protoDUNE-Single Phase and protDUNE-DualPhase

    CERN Multimedia

    Brice, Maximilien

    2016-01-01

    At the EHN1 two big 8m x 8m x8m detector prototypes (protoDUNE-Single Phase and protDUNE-DualPhase) are being constructed. The aim is to test technologies and detector performances for DUNE, a new generation of LBN neutr

  5. Free energy and phase equilibria for the restricted primitive model of ionic fluids from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Orkoulas, G.; Panagiotopoulos, A.Z.

    1994-01-01

    In this work, we investigate the liquid--vapor phase transition of the restricted primitive model of ionic fluids. We show that at the low temperatures where the phase transition occurs, the system cannot be studied by conventional molecular simulation methods because convergence to equilibrium is slow. To accelerate convergence, we propose cluster Monte Carlo moves capable of moving more than one particle at a time. We then address the issue of charged particle transfers in grand canonical and Gibbs ensemble Monte Carlo simulations, for which we propose a biased particle insertion/destruction scheme capable of sampling short interparticle distances. We compute the chemical potential for the restricted primitive model as a function of temperature and density from grand canonical Monte Carlo simulations and the phase envelope from Gibbs Monte Carlo simulations. Our calculated phase coexistence curve is in agreement with recent results of Caillol obtained on the four-dimensional hypersphere and our own earlier Gibbs ensemble simulations with single-ion transfers, with the exception of the critical temperature, which is lower in the current calculations. Our best estimates for the critical parameters are T * c =0.053, ρ * c =0.025. We conclude with possible future applications of the biased techniques developed here for phase equilibrium calculations for ionic fluids

  6. Experimental investigations of single and two-phase flow in a heated rod bundle

    International Nuclear Information System (INIS)

    Barthel, Frank; Franz, Ronald; Hampel, Uwe; Technische Univ. Dresden

    2013-01-01

    An experimental facility for the study of boiling flows in a 3 x 3 rod bundle geometry was setup. The bundle resembles in essential geometrical parts the geometry in a pressurized water reactor fuel element. The facility is operated with a refrigerant fluid. Beside standard instrumentation for temperature, pressure and flow rate we employed particle image velocimetry for single phase flow studies, gamma ray densitometry for integral gas fraction measurement sand ultrafast X-ray tomography for the study of the void dynamics in the cross-section. Moreover extensive thermo-instrumentation allows axial rod surface temperature measurements for the central heated rod. First results will be discussed in this article. (orig.)

  7. Mass sensors with mechanical traps for weighing single cells in different fluids.

    Science.gov (United States)

    Weng, Yaochung; Delgado, Francisco Feijó; Son, Sungmin; Burg, Thomas P; Wasserman, Steven C; Manalis, Scott R

    2011-12-21

    We present two methods by which single cells can be mechanically trapped and continuously monitored within the suspended microchannel resonator (SMR) mass sensor. Since the fluid surrounding the trapped cell can be quickly and completely replaced on demand, our methods are well suited for measuring changes in cell size and growth in response to drugs or other chemical stimuli. We validate our methods by measuring the density of single polystyrene beads and Saccharomyces cerevisiae yeast cells with a precision of approximately 10(-3) g cm(-3), and by monitoring the growth of single mouse lymphoblast cells before and after drug treatment.

  8. Two-fluid model of two-phase flow in a pin bundle of a nuclear reactor

    International Nuclear Information System (INIS)

    Chawla, T.C.; Ishii, M.

    1980-01-01

    By considering two-phase flow as a field which is subdivided into two turbulent single-phase regions with moving boundaries separating the two constituent phases, such that the differential balances for three-dimensional turbulent flow hold for each subregion and for the interface, we perform the Eulerian area averaging over the cross-sectional area of each phase in a given channel and segment averaging of transverse momentum equation along the phase intercepts at the interchannel boundaries. To simplify the governing equations obtained as a result of these operations, we invoke the assumption that the motion of the fluid in each phase is dominantly in axial direction, that is the transverse components of velocity are small compared to axial components. We further assume that the variation of axial component of velocity within a channel is much stronger than the variation along the axial direction. We also assume that similar arguments can also be applied to the variation of enthalpy in a channel. As a result of these considerations, we obtain two sets of continuity, momentum, and energy equations describing motion of each phase in the axial direction. The phasic interaction terms which appear in these equations are governed by interfacial transfer conditions obtained from interface balances. The segment-averaged transverse-momentum equation for each phase provides the governing equation for cross flow. (author)

  9. Long-wave equivalent viscoelastic solids for porous rocks saturated by two-phase fluids

    Science.gov (United States)

    Santos, J. E.; Savioli, G. B.

    2018-04-01

    Seismic waves traveling across fluid-saturated poroelastic materials with mesoscopic-scale heterogeneities induce fluid flow and Biot's slow waves generating energy loss and velocity dispersion. Using Biot's equations of motion to model these type of heterogeneities would require extremely fine meshes. We propose a numerical upscaling procedure to determine the complex and frequency dependent P-wave and shear moduli of an effective viscoelastic medium long-wave equivalent to a poroelastic solid saturated by a two-phase fluid. The two-phase fluid is defined in terms of capillary pressure and relative permeability flow functions. The P-wave and shear effective moduli are determined using harmonic compressibility and shear experiments applied on representative samples of the bulk material. Each experiment is associated with a boundary value problem that is solved using the finite element method. Since a poroelastic solid saturated by a two-phase fluid supports the existence of two slow waves, this upscaling procedure allows to analyze their effect on the mesoscopic-loss mechanism in hydrocarbon reservoir formations. Numerical results show that a two-phase Biot medium model predicts higher attenuation than classic Biot models.

  10. Laser doppler anemometry in single- and two-phase flows

    International Nuclear Information System (INIS)

    Durst, F.

    1976-01-01

    The present report gives an introduction into laser-Doppler anemometry and tries to explain the basic physical principles of this measuring technique. Moire fringe patterns are used in order to visually model LDA-signals and to explain the basic difference in optical systems. It is pointed out that LDA measurements in highly turbulent flows and in two-phase flows should be attempted with direction sensitive instruments only. Some of the optical systems developed by the author and his collaborators are introduced and their functioning in measurements is demonstrated. These measurements embrace investigations in a number of single-phase flows including flames. (orig.) [de

  11. Phase-Shifting Liquid Crystal Interferometers for Microgravity Fluid Physics

    Science.gov (United States)

    Griffin, DeVon W.; Marshall, Keneth L.

    2002-01-01

    The initial focus of this project was to eliminate both of these problems in the Liquid Crystal Point-Diffraction Interferometer (LCPDI). Progress toward that goal will be described, along with the demonstration of a phase shifting Liquid Crystal Shearing Interferometer (LCSI) that was developed as part of this work. The latest LCPDI, other than a lens to focus the light from a test section onto a diffracting microsphere within the interferometer and a collimated laser for illumination, the pink region contained within the glass plates on the rod-mounted platform is the complete interferometer. The total width is approximately 1.5 inches with 0.25 inches on each side for bonding the electrical leads. It is 1 inch high and there are only four diffracting microspheres within the interferometer. As a result, it is very easy to align, achieving the first goal. The liquid crystal electro-optical response time is a function of layer thickness, with thinner devices switching faster due to a reduction in long-range viscoelastic forces between the LC molecules. The LCPDI has a liquid crystal layer thickness of 10 microns, which is controlled by plastic or glass microspheres embedded in epoxy 'pads' at the corners of the device. The diffracting spheres are composed of polystyrene/divinyl benzene polymer with an initial diameter of 15 microns. The spheres deform slightly when the interferometer is assembled to conform to the spacing produced by the microsphere-filled epoxy spacer pads. While the speed of this interferometer has not yet been tested, previous LCPDIs fabricated at the Laboratory for Laser Energetics switched at a rate of approximately 3.3 Hz, a factor of 10 slower than desired. We anticipate better performance when the speed of these interferometers is tested since they are approximately three times thinner. Phase shifting in these devices is a function of the AC voltage level applied to the liquid crystal. As the voltage increases, the dye in the liquid crystal

  12. Hydrodynamics of single- and two-phase flow in inclined rod arrays

    International Nuclear Information System (INIS)

    Todreas, N.E.

    1984-01-01

    Required inputs for thermal-hydraulic codes are constitutive relations for fluid-solid flow resistance, in single-phase flow, and interfacial momentum exchange (relative phase motion), in two-phase flow. An inclined rod array air-water experiment was constructed to study the hydrodynamics of multidimensional porous medium flow in rod arrays. Velocities, pressures, bubble distributions, and void fractions were measured in inline and rotational square rod arrays of P/d = 1.5, at 0, 30, 45, and 90 degree inclinations to the vertical flow direction. Constitutive models for single-phase flow resistance are reviewed, new comprehensive models developed, and an assessment with previously published and new data made. The principle of superimposing one-dimensional correlations proves successful for turbulent single-phase inclined flow. For bubbly two-phase yawed flow through incline rod arrays a new flow separation phenomena was observed and modeled. Bubbles of diameters significantly smaller than the rod diameter travel along the rod axis, while larger diameter bubbles move through the rod array gaps. The outcome is a flow separation not predictable with current interfacial momentum exchange models. This phenomenon was not observed in rotated square rod arrays. Current interfacial momentum exchange models were confirmed for this rod arrangement. Models for the two phase flow resistance multiplier for cross flow were reviewed and compared with data from cross and yawed flow rod arrays. Both drag and lift components of the multiplier were well predicted by the homogenous model. Other models reviewed overpredicted the data by a factor of two

  13. Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

    International Nuclear Information System (INIS)

    Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun

    2006-01-01

    A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors)

  14. Overview of Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    A continuous booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the imperative demand of “clean” power generation from renewables. Grid-connected PV systems will thus become an even more active player in the future mixed power systems, which...... systems. This chapter thus gives an overview of the advancement of power electronics converters in single-phase grid-connected PV systems, being commonly used in residential applications. Demands to single-phase grid-connected PV systems and the general control strategies are also addressed...... are linked together by a vast of power electronics converters and the power grid. In order to achieve a reliable and efficient power generation from PV systems, more stringent demands have been imposed on the entire PV system. It, in return, advances the development of the power converter technology in PV...

  15. Multi-scale Modeling of Compressible Single-phase Flow in Porous Media using Molecular Simulation

    KAUST Repository

    Saad, Ahmed Mohamed

    2016-05-01

    In this study, an efficient coupling between Monte Carlo (MC) molecular simulation and Darcy-scale flow in porous media is presented. The cell-centered finite difference method with a non-uniform rectangular mesh were used to discretize the simulation domain and solve the governing equations. To speed up the MC simulations, we implemented a recently developed scheme that quickly generates MC Markov chains out of pre-computed ones, based on the reweighting and reconstruction algorithm. This method astonishingly reduces the required computational time by MC simulations from hours to seconds. In addition, the reweighting and reconstruction scheme, which was originally designed to work with the LJ potential model, is extended to work with a potential model that accounts for the molecular quadrupole moment of fluids with non-spherical molecules such as CO2. The potential model was used to simulate the thermodynamic equilibrium properties for single-phase and two-phase systems using the canonical ensemble and the Gibbs ensemble, respectively. Comparing the simulation results with the experimental data showed that the implemented model has an excellent fit outperforming the standard LJ model. To demonstrate the strength of the proposed coupling in terms of computational time efficiency and numerical accuracy in fluid properties, various numerical experiments covering different compressible single-phase flow scenarios were conducted. The novelty in the introduced scheme is in allowing an efficient coupling of the molecular scale and Darcy scale in reservoir simulators. This leads to an accurate description of the thermodynamic behavior of the simulated reservoir fluids; consequently enhancing the confidence in the flow predictions in porous media.

  16. Permanent split capacitor single phase electric motor system

    Science.gov (United States)

    Kirschbaum, H.S.

    1984-08-14

    A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation. 4 figs.

  17. Berry-phase blockade in single-molecule magnets

    OpenAIRE

    Gonzalez, Gabriel; Leuenberger, Michael N.

    2006-01-01

    We formulate the problem of electron transport through a single-molecule magnet (SMM) in the Coulomb blockade regime taking into account topological interference effects for the tunneling of the large spin of a SMM. The interference originates from spin Berry phases associated with different tunneling paths. We show that in the case of incoherent spin states it is essential to place the SMM between oppositely spin-polarized source and drain leads in order to detect the spin tunneling in the s...

  18. Single beam Fourier transform digital holographic quantitative phase microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Anand, A., E-mail: arun-nair-in@yahoo.com; Chhaniwal, V. K.; Mahajan, S.; Trivedi, V. [Optics Laboratory, Applied Physics Department, Faculty of Technology and Engineering, M.S. University of Baroda, Vadodara 390001 (India); Faridian, A.; Pedrini, G.; Osten, W. [Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart (Germany); Dubey, S. K. [Siemens Technology and Services Pvt. Ltd, Corporate Technology—Research and Technology Centre, Bangalore 560100 (India); Javidi, B. [Department of Electrical and Computer Engineering, U-4157, University of Connecticut, Storrs, Connecticut 06269-2157 (United States)

    2014-03-10

    Quantitative phase contrast microscopy reveals thickness or height information of a biological or technical micro-object under investigation. The information obtained from this process provides a means to study their dynamics. Digital holographic (DH) microscopy is one of the most used, state of the art single-shot quantitative techniques for three dimensional imaging of living cells. Conventional off axis DH microscopy directly provides phase contrast images of the objects. However, this process requires two separate beams and their ratio adjustment for high contrast interference fringes. Also the use of two separate beams may make the system more vulnerable to vibrations. Single beam techniques can overcome these hurdles while remaining compact as well. Here, we describe the development of a single beam DH microscope providing whole field imaging of micro-objects. A hologram of the magnified object projected on to a diffuser co-located with a pinhole is recorded with the use of a commercially available diode laser and an arrayed sensor. A Fourier transform of the recorded hologram directly yields the complex amplitude at the image plane. The method proposed was investigated using various phase objects. It was also used to image the dynamics of human red blood cells in which sub-micrometer level thickness variation were measurable.

  19. Formation of structural steady states in lamellar/sponge phase-separating fluids under shear flow

    Science.gov (United States)

    Panizza, P.; Courbin, L.; Cristobal, G.; Rouch, J.; Narayanan, T.

    2003-05-01

    We investigate the effect of shear flow on a lamellar-sponge phase-separating fluid when subjected to shear flow. We show the existence of two different steady states (droplets and ribbons structures) whose nature does not depend on the way to reach the two-phase unstable region of the phase diagram (temperature quench or stirring). The transition between ribbons and droplets is shear thickening and its nature strongly depends on what dynamical variable is imposed. If the stress is fixed, flow visualization shows the existence of shear bands at the transition, characteristic of coexistence in the cell between ribbons and droplets. In this shear-banding region, the viscosity oscillates. When the shear rate is fixed, no shear bands are observed. Instead, the transition exhibits a hysteretic behavior leading to a structural bi-stability of the phase-separating fluid under flow.

  20. Spectral decomposition of single-tone-driven quantum phase modulation

    International Nuclear Information System (INIS)

    Capmany, Jose; Fernandez-Pousa, Carlos R

    2011-01-01

    Electro-optic phase modulators driven by a single radio-frequency tone Ω can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of ℎΩ. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F 1 , the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F 1 is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  1. Spectral decomposition of single-tone-driven quantum phase modulation

    Energy Technology Data Exchange (ETDEWEB)

    Capmany, Jose [ITEAM Research Institute, Univ. Politecnica de Valencia, 46022 Valencia (Spain); Fernandez-Pousa, Carlos R, E-mail: c.pousa@umh.es [Signal Theory and Communications, Department of Physics and Computer Science, Univ. Miguel Hernandez, 03202 Elche (Spain)

    2011-02-14

    Electro-optic phase modulators driven by a single radio-frequency tone {Omega} can be described at the quantum level as scattering devices where input single-mode radiation undergoes energy changes in multiples of {h_bar}{Omega}. In this paper, we study the spectral representation of the unitary, multimode scattering operator describing these devices. The eigenvalue equation, phase modulation being a process preserving the photon number, is solved at each subspace with definite number of photons. In the one-photon subspace F{sub 1}, the problem is equivalent to the computation of the continuous spectrum of the Susskind-Glogower cosine operator of the harmonic oscillator. Using this analogy, the spectral decomposition in F{sub 1} is constructed and shown to be equivalent to the usual Fock-space representation. The result is then generalized to arbitrary N-photon subspaces, where eigenvectors are symmetrized combinations of N one-photon eigenvectors and the continuous spectrum spans the entire unit circle. Approximate normalizable one-photon eigenstates are constructed in terms of London phase states truncated to optical bands. Finally, we show that synchronous ultrashort pulse trains represent classical field configurations with the same structure as these approximate eigenstates, and that they can be considered as approximate eigenvectors of the classical formulation of phase modulation.

  2. Phenomena at the QCD phase transition in nonequilibrium chiral fluid dynamics (NχFD)

    Energy Technology Data Exchange (ETDEWEB)

    Nahrgang, Marlene [Duke University, Department of Physics, Durham, NC (United States); Herold, Christoph [Suranaree University of Technology, School of Physics, Nakhon Ratchasima (Thailand)

    2016-08-15

    Heavy-ion collisions performed in the beam energy range accessible by the NICA collider facility are expected to produce systems of extreme net-baryon densities and can thus reach yet unexplored regions of the QCD phase diagram. Here, one expects the phase transition between the plasma of deconfined quarks and gluons and the hadronic matter to be of first order. A discovery of the first-order phase transition would as well prove the existence of the QCD critical point, a landmark in the phase diagram. In order to understand possible signals of the first-order phase transition in heavy-ion collision experiments it is very important to develop dynamical models of the phase transition. Here, we discuss the opportunities of studying dynamical effects at the QCD first-order phase transition within our model of nonequilibrium chiral fluid dynamics. (orig.)

  3. Effect of completion geometry and phasing on single-phase liquid flow behaviour in horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, H.; Sarica, C.; Brill, P. [Tulsa Unov., OK (United States)

    1998-12-31

    The effects of completion geometries and the phasing and density of injection openings in horizontal wells was studied. A total of 1,257 tests were conducted for no fluid injections, no main flow at the test section inlet, and with fluid injection for Reynolds numbers ranging from 4,000 to 60,000 and for influx to main flow rate ratios ranging from 1/5 to 1/2000. Results demonstrated the dramatic effects of completion geometry, phasing density, Reynolds number and main flow rate on the pressure behaviour and therefore on the production behaviour of the well. A general friction factor expression for horizontal wells with multiple injection openings was developed based on the conservation of mass and momentum and using a commercial Computational Fluid Dynamics (CFD) computer program to determine the length of the flow developing region in a horizontal well. A field example is presented to show the importance of using the proper friction factor correlation to calculate the pressure drop in a horizontal well. 32 refs., 4 tabs., 20 figs.

  4. Hybrid Three-Phase/Single-Phase Microgrid Architecture with Power Management Capabilities

    DEFF Research Database (Denmark)

    Sun, Qiuye; Zhou, Jianguo; Guerrero, Josep M.

    2015-01-01

    With the fast proliferation of single-phase distributed generation (DG) units and loads integrated into residential microgrids, independent power sharing per phase and full use of the energy generated by DGs have become crucial. To address these issues, this paper proposes a hybrid microgrid...... architecture and its power management strategy. In this microgrid structure, a power sharing unit (PSU), composed of three single-phase back-to-back (SPBTB) converters, is proposed to be installed at the point of common coupling (PCC). The aim of the PSU is mainly to realize the power exchange and coordinated...... control of load power sharing among phases, as well as to allow fully utilization of the energy generated by DGs. Meanwhile, the method combining the modified adaptive backstepping-sliding mode control approach and droop control is also proposed to design the SPBTB system controllers. With the application...

  5. Study of Two-Phase Heat Transfer in Nano-fluids for Nuclear Applications

    International Nuclear Information System (INIS)

    Kim, S.J.; Truong, B.; Buongiorno, J.; Hu, L.W.; Bang, I.C.

    2006-01-01

    Nano-fluids are engineered colloidal suspensions of nano-particles in a base fluid. We are investigating the two-phase heat transfer behavior of water-based nano-fluids, to evaluate their potential use in nuclear applications, including the PWR primary coolant and PWR and BWR safety systems. A simple pool boiling wire experiment shows that a significant increase in Critical Heat Flux (CHF) can be achieved at modest nano-particle concentrations. For example, the CHF increases by 50% in nano-fluids with alumina nano-particles at 0.001%v concentration. The CHF enhancement appears to correlate with the presence of a layer of nano-particles that builds up on the heated surface during nucleate boiling. A review of the prevalent Departure from Nucleate Boiling (DNB) theories suggests that an alteration of the nucleation site density (brought about by the nano-particle layer) could plausibly explain the CHF enhancement. (authors)

  6. Phase diagram and transport properties for hydrogen-helium fluid planets

    International Nuclear Information System (INIS)

    Stevenson, D.J.; Salpeter, E.E.

    1977-01-01

    Hydrogen and helium are the major constituents of Jupiter and Saturn, and phase transitions can have important effects on the planetary structure. In this paper, the relevant phase diagrams and microscopic transport properties are analyzed in detail. The following paper (Paper II) applies these results to the evolution and present dynamic structure of the Jovian planets.Pure hydrogen is first discussed, especially the nature of the molecular-metallic transition and the melting curves for the two phases. It is concluded that at the temperatures and pressures of interest (Tapprox. =10 4 K, Papprox. =1--10 Mbar), both phases are fluid, but the transition between them might nevertheless be first-order. The insulator-metal transition in helium occurs at a much higher pressure (approx.70 Mbars) and is not of interest.The phase diagrams for both molecular and metallic hydrogen-helium mixtures are discussed. In the metallic mixture, calculations indicate a miscibility gap for T9 or approx. =10 4 K. Immiscibility in the molecular mixture is more difficult to predict but almost certainly occurs at much lower temperatures. A fluid-state model is constructed which predicts the likely topology of the three-dimensional phase diagram. The greater solubility of helium in the molecular phase leads to the prediction that the He/H mass ratio is typically twice as large in the molecular phase as in the coexisting metallic phase. Under these circumstances a ''density inversion'' is possible in which the molecular phase becomes more dense than the metallic phase.The partitioning of minor constituents is also considered: The deuterium/hydrogen mass ratio is essentially the same for all coexisting hydrogen-helium phases, at least for T> or approx. =5000 K. The partitioning of H 2 O, CH 4 , and NH 3 probably favors the molecular (or helium-rich) phase. Substances with high conduction electron density (e.g., Al) may partition into the metallic phase

  7. Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

    KAUST Repository

    Ma, Zhiwei

    2013-05-06

    The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

  8. Phase Behaviors of Reservoir Fluids with Capillary Eff ect Using Particle Swarm Optimization

    KAUST Repository

    Ma, Zhiwei

    2013-01-01

    The study of phase behavior is important for the oil and gas industry. Many approaches have been proposed and developed for phase behavior calculation. In this thesis, an alternative method is introduced to study the phase behavior by means of minimization of Helmholtz free energy. For a system at fixed volume, constant temperature and constant number of moles, the Helmholtz free energy reaches minimum at the equilibrium state. Based on this theory, a stochastic method called Particle Swarm Optimization (PSO) algorithm, is implemented to compute the phase diagrams for several pure component and mixture systems. After comparing with experimental and the classical PT-ash calculation, we found the phase diagrams obtained by minimization of the Helmholtz Free Energy approach match the experimental and theoretical diagrams very well. Capillary effect is also considered in this thesis because it has a significant influence on the phase behavior of reservoir fluids. In this part, we focus on computing the phase envelopes, which consists of bubble and dew point lines. Both fixed and calculated capillary pressure from the Young-Laplace equation cases are introduced to study their effects on phase envelopes. We found that the existence of capillary pressure will change the phase envelopes. Positive capillary pressure reduces the dew point and bubble point temperatures under the same pressure condition, while the negative capillary pressure increases the dew point and bubble point temperatures. In addition, the change of contact angle and pore radius will affect the phase envelope. The effect of the pore radius on the phase envelope is insignificant when the radius is very large. These results may become reference for future research and study. Keywords: Phase Behavior; Particle Swarm Optimization; Capillary Pressure; Reservoir Fluids; Phase Equilibrium; Phase Envelope.

  9. The constitutive distributed parameter model of multicomponent chemical processes in gas, fluid and solid phase

    International Nuclear Information System (INIS)

    Niemiec, W.

    1985-01-01

    In the literature of distributed parameter modelling of real processes is not considered the class of multicomponent chemical processes in gas, fluid and solid phase. The aim of paper is constitutive distributed parameter physicochemical model, constructed on kinetics and phenomenal analysis of multicomponent chemical processes in gas, fluid and solid phase. The mass, energy and momentum aspects of these multicomponent chemical reactions and adequate phenomena are utilized in balance operations, by conditions of: constitutive invariance for continuous media with space and time memories, reciprocity principle for isotropic and anisotropic nonhomogeneous media with space and time memories, application of definitions of following derivative and equation of continuity, to the construction of systems of partial differential constitutive state equations, in the following derivative forms for gas, fluid and solid phase. Couched in this way all physicochemical conditions of multicomponent chemical processes in gas, fluid and solid phase are new form of constitutive distributed parameter model for automatics and its systems of equations are new form of systems of partial differential constitutive state equations in sense of phenomenal distributed parameter control

  10. Computational fluid dynamics simulations of blood flow regularized by 3D phase contrast MRI

    DEFF Research Database (Denmark)

    Rispoli, Vinicius C; Nielsen, Jon; Nayak, Krishna S

    2015-01-01

    BACKGROUND: Phase contrast magnetic resonance imaging (PC-MRI) is used clinically for quantitative assessment of cardiovascular flow and function, as it is capable of providing directly-measured 3D velocity maps. Alternatively, vascular flow can be estimated from model-based computation fluid dyn...

  11. Mathematical well-posedness of a two-fluid equations for bubbly two-phase flows

    International Nuclear Information System (INIS)

    Okawa, Tomio; Kataoka, Isao

    2000-01-01

    It is widely known that two-fluid equations used in most engineering applications do not satisfy the necessary condition for being mathematical well-posed as initial-value problems. In the case of stratified two-phase flows, several researchers have revealed that differential models satisfying the necessary condition are to be derived if the pressure difference between the phases is related to the spatial gradient of the void fraction through the effects of gravity or surface tension. While, in the case of dispersed two-phase flows, no physically reasonable method to derive mathematically well-posed two-fluid model has been proposed. In the present study, particularly focusing on the effect of interfacial pressure terms, we derived the mathematically closed form of the volume-averaged two-fluid model for bubbly two-phase flows. As a result of characteristic analyses, it was shown that the proposed two-fluid equations satisfy the necessary condition of mathematical well-posedness if the void fraction is sufficiently small. (author)

  12. RELAP5 two-phase fluid model and numerical scheme for economic LWR system simulation

    International Nuclear Information System (INIS)

    Ransom, V.H.; Wagner, R.J.; Trapp, J.A.

    1981-01-01

    The RELAP5 two-phase fluid model and the associated numerical scheme are summarized. The experience accrued in development of a fast running light water reactor system transient analysis code is reviewed and example of the code application are given

  13. Investigation on a Novel Discontinuous Pulse-Width Modulation Algorithm for Single-phase Voltage Source Rectifier

    DEFF Research Database (Denmark)

    Qu, Hao; Yang, Xijun; Guo, Yougui

    2014-01-01

    Single-phase voltage source converter (VSC) is an important power electronic converter (PEC), including single-phase voltage source inverter (VSI), single-phase voltage source rectifier (VSR), single-phase active power filter (APF) and single-phase grid-connection inverter (GCI). Single-phase VSC...

  14. Single lipid vesicle assay for characterizing single-enzyme kinetics of phospholipid hydrolysis in a complex biological fluid.

    Science.gov (United States)

    Tabaei, Seyed R; Rabe, Michael; Zetterberg, Henrik; Zhdanov, Vladimir P; Höök, Fredrik

    2013-09-25

    Imaging of individual lipid vesicles is used to track single-enzyme kinetics of phospholipid hydrolysis. The method is employed to quantify the catalytic activity of phospholipase A2 (PLA2) in both pure and complex biological fluids. The measurements are demonstrated to offer a subpicomolar limit of detection (LOD) of human secretory PLA2 (sPLA2) in up to 1000-fold-diluted cerebrospinal fluid (CSF). An additional new feature provided by the single-enzyme sensitivity is that information about both relative concentration variations of active sPLA2 in CSF and the specific enzymatic activity can be simultaneously obtained. When CSF samples from healthy controls and individuals diagnosed with Alzheimer's disease (AD) are analyzed, the specific enzymatic activity is found to be preserved within 7% in the different CSF samples whereas the enzyme concentration differs by up to 56%. This suggests that the previously reported difference in PLA2 activity in CSF samples from healthy and AD individuals originates from differences in the PLA2 expression level rather than from the enzyme activity. Conventional ensemble averaging methods used to probe sPLA2 activity do not allow one to obtain such information. Together with an improvement in the LOD of at least 1 order of magnitude compared to that of conventional assays, this suggests that the method will become useful in furthering our understanding of the role of PLA2 in health and disease and in detecting the pharmacodynamic effects of PLA2-targeting drug candidates.

  15. Analysis of I-Br-Cl in single fluid inclusions by LA-ICP-MS

    Science.gov (United States)

    Giehl, C.; Fusswinkel, T.; Beermann, O.; Garbe-Schönberg, D.; Scholten, L.; Wagner, T.

    2017-12-01

    Halogens are excellent tracers of hydrothermal fluid sources and in-situ LA-ICP-MS analysis of Cl and Br in single fluid inclusions has provided fundamentally new insight into hydrothermal fluid flow and ore formation. There is mounting evidence that enrichment and depletion of Br relative to Cl may be caused by a number of processes beyond seawater evaporation and halite dissolution which cannot be discriminated on the basis of Br/Cl ratios alone. Expanding the analytical capabilities of fluid inclusion LA-ICP-MS analysis to include iodine would allow to discern between selective and coupled enrichment processes of Cl, Br and I, even in geologically complex samples that are inaccessible to bulk extraction techniques. We present iodine concentration data determined by LA-ICP-MS analysis of synthetic fluid inclusions, using the Sca17 scapolite reference material for external standardization (Seo et al., 2011). Iodine concentrations in Sca17 were determined using the Durango apatite standard. Four starting solutions containing I (0.3, 1.5, 27, 78 µg/g), Br (941, 1403, 2868, 4275 µg/g), Na (30.7, 94.7 mg/g), and Cl (50, 137 mg/g) (analyzed by ICP-OES and ICP-MS at CAU Kiel) were prepared by dissolving reagent grade chemical powders in ultra-pure water. Spherical inclusions (up to 40 µm) were synthesized from the starting solutions in pre-cracked, HF-treated synthetic quartz crystals which were placed in gold capsules and equilibrated at 600°C, 100/200 MPa in cold seal pressure vessels. Fluid inclusion LA-ICP-MS analysis (University of Helsinki) yielded average I concentrations in excellent agreement with the starting solutions (27.3 µg/g ± 14 %RSD for the 27 µg/g solution and 77.6 µg/g ± 8.3 %RSD for the 78 µg/g solution). Average Br and I concentrations deviate less than 10 % from solution concentration values. For the low I concentration solutions, the synthetic inclusions were too small to detect I. Thus, given suitable standard materials and sufficient

  16. Ultrasound Microbubble Treatment Enhances Clathrin-Mediated Endocytosis and Fluid-Phase Uptake through Distinct Mechanisms.

    Directory of Open Access Journals (Sweden)

    Farnaz Fekri

    Full Text Available Drug delivery to tumors is limited by several factors, including drug permeability of the target cell plasma membrane. Ultrasound in combination with microbubbles (USMB is a promising strategy to overcome these limitations. USMB treatment elicits enhanced cellular uptake of materials such as drugs, in part as a result of sheer stress and formation of transient membrane pores. Pores formed upon USMB treatment are rapidly resealed, suggesting that other processes such as enhanced endocytosis may contribute to the enhanced material uptake by cells upon USMB treatment. How USMB regulates endocytic processes remains incompletely understood. Cells constitutively utilize several distinct mechanisms of endocytosis, including clathrin-mediated endocytosis (CME for the internalization of receptor-bound macromolecules such as Transferrin Receptor (TfR, and distinct mechanism(s that mediate the majority of fluid-phase endocytosis. Tracking the abundance of TfR on the cell surface and the internalization of its ligand transferrin revealed that USMB acutely enhances the rate of CME. Total internal reflection fluorescence microscopy experiments revealed that USMB treatment altered the assembly of clathrin-coated pits, the basic structural units of CME. In addition, the rate of fluid-phase endocytosis was enhanced, but with delayed onset upon USMB treatment relative to the enhancement of CME, suggesting that the two processes are distinctly regulated by USMB. Indeed, vacuolin-1 or desipramine treatment prevented the enhancement of CME but not of fluid phase endocytosis upon USMB, suggesting that lysosome exocytosis and acid sphingomyelinase, respectively, are required for the regulation of CME but not fluid phase endocytosis upon USMB treatment. These results indicate that USMB enhances both CME and fluid phase endocytosis through distinct signaling mechanisms, and suggest that strategies for potentiating the enhancement of endocytosis upon USMB treatment may

  17. Phase transitions of single polymer chains and of polymer solutions: insights from Monte Carlo simulations

    International Nuclear Information System (INIS)

    Binder, K; Paul, W; Strauch, T; Rampf, F; Ivanov, V; Luettmer-Strathmann, J

    2008-01-01

    The statistical mechanics of flexible and semiflexible macromolecules is distinct from that of small molecule systems, since the thermodynamic limit can also be approached when the number of (effective) monomers of a single chain (realizable by a polymer solution in the dilute limit) is approaching infinity. One can introduce effective attractive interactions into a simulation model for a single chain such that a swollen coil contracts when the temperature is reduced, until excluded volume interactions are effectively canceled by attractive forces, and the chain conformation becomes almost Gaussian at the theta point. This state corresponds to a tricritical point, as the renormalization group theory shows. Below the theta temperature a fluid globule is predicted (at nonzero concentration then phase separation between dilute and semidilute solutions occurs), while at still lower temperature a transition to a solid phase (crystal or glass) occurs. Monte Carlo simulations have shown, however, that the fluid globule phase may become suppressed, when the range of the effective attractive forces becomes too short, with the result that a direct (ultimately first-order) transition from the swollen coil to the solid occurs. This behavior is analogous to the behavior of colloidal particles with a very short range of attractive forces, where liquid-vapor-type phase separation may be suppressed. Analogous first-order transitions from swollen coils to dense rodlike or toroidal structures occur for semiflexible polymers. Finally, the modifications of the behavior discussed when the polymers are adsorbed at surfaces are also mentioned, and possible relations to wetting behavior of polymer solutions are addressed.

  18. An experimental and numerical study of developed single phase axial turbulent flow in a smooth rod bundle

    International Nuclear Information System (INIS)

    Hooper, J.D.

    1977-01-01

    A combined experimental and numerical model of a turbulent single phase coolant, flowing axially along the fuel pins of a nuclear reactor, was developed. The experimental rig represented two interconnected subchannels of a square array at a pitch/diameter ratio of 1.193. Air was the working fluid, and measurements were made of the mean radial velocity profiles, wall shear stress variation, turbulence velocity spectra and intensities. The numerically predicted wall shear distribution and mean velocity profiles, obtained using an empirical two-dimensional mixing length and eddy diffusivity concept to represent fluid turbulence, showed good agreement with the experimental results. (Author)

  19. Simulation of the phenomenon of single-phase and two-phase natural circulation

    International Nuclear Information System (INIS)

    Castrillo, Lazara Silveira

    1998-02-01

    Natural convection phenomenon is often used to remove the residual heat from the surfaces of bodies where the heat is generated e.g. during accidents or transients of nuclear power plants. Experimental study of natural circulation can be done in small scale experimental circuits and the results can be extrapolated for larger operational facilities. The numerical analysis of transients can be carried out by using large computational codes that simulate the thermohydraulic behavior in such facilities. The computational code RELAP5/MOD2, (Reactor Excursion and Leak Analysis Program) was developed by U.S. Nuclear Regulatory Commissions's. Division of Reactor Safety Research with the objective of analysis of transients and postulated accidents in the light water reactor (LWR) systems, including small and large ruptures with loss of coolant accidents (LOCA's). The results obtained by the simulation of single-phase and two-phase natural circulation, using the RELAP5/MOD2, are presented in this work. The study was carried out using the experimental circuit built at the 'Departamento de Engenharia Quimica da Escola Politecnica da Universidade de Sao Paulo'. In the circuit, two experiments were carried out with different conditions of power and mass flow, obtaining a single-phase regime with a level of power of 4706 W and flow of 5.10 -5 m 3 /s (3 l/min) and a two-phase regime with a level of power of 6536 W and secondary flow 2,33.10 -5 m 3 /s (1,4 l/min). The study allowed tio evaluate the capacity of the code for representing such phenomena as well as comparing the transients obtained theoretically with the experimental results. The comparative analysis shows that the code represents fairly well the single-phase transient, but the results for two-phase transients, starting from the nodalization and calibration used for the case single-phase transient, did not reproduce faithfully some experimental results. (author)

  20. Potential pitfalls of single phasing operation in a three phase distribution network

    Energy Technology Data Exchange (ETDEWEB)

    Narayanan, V S

    1986-07-01

    Finding it difficult to cope with the increased demand for electric power, some electricity boards have resorted to single phasing techniques in distribution system. This practice is harmful to the equipment in the power system. Some of the potential dangers associated with this undesirable practice are briefly discussed.

  1. Analysis of single oil-bearing fluid inclusions in mid-Proterozoic sandstones (Roper Group, Australia)

    Science.gov (United States)

    Siljeström, Sandra; Volk, Herbert; George, Simon C.; Lausmaa, Jukka; Sjövall, Peter; Dutkiewicz, Adriana; Hode, Tomas

    2013-12-01

    Hydrocarbons and organic biomarkers extracted from black shales and other carbonaceous sedimentary rocks are valuable sources of information on the biodiversity and environment of early Earth. However, many Precambrian hydrocarbons including biomarkers are suspected of being younger contamination. An alternative approach is to study biomarkers trapped in oil-bearing fluid inclusions by bulk crushing samples and subsequently analysing the extracted hydrocarbons with gas chromatography-mass spectrometry. However, this method does not constrain the hydrocarbons to one particular oil inclusion, which means that if several different generations of oil inclusions are present in the sample, a mix of the content from these oil inclusions will be analysed. In addition, samples with few and/or small inclusions are often below the detection limit. Recently, we showed that it is possible to detect organic biomarkers in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In the present study, single fluid inclusion analysis has been performed on Proterozoic samples for the first time. Four individual oil-bearing fluid inclusions, found in 1430 Ma sandstone from the Roper Superbasin in Northern Australia, were analysed with ToF-SIMS. The ToF-SIMS spectra of the oil in the different inclusions are very similar to each other and are consistent with the presence of n-alkanes/branched alkanes, monocyclic alkanes, bicyclic alkanes, aromatic hydrocarbons, and tetracyclic and pentacyclic hydrocarbons. These results are in agreement with those obtained from bulk crushing of inclusions trapped in the same samples. The capability to analyse the hydrocarbon and biomarker composition of single oil-bearing fluid inclusions is a major breakthrough, as it opens up a way of obtaining molecular compositional data on ancient oils without the ambiguity of the origin of these hydrocarbons. Additionally, this finding suggests that it will be possible

  2. Computational simulation of flow and heat transfer in single-phase natural circulation loops

    International Nuclear Information System (INIS)

    Pinheiro, Larissa Cunha

    2017-01-01

    Passive decay heat removal systems based on natural circulation are essential assets for the new Gen III+ nuclear power reactors and nuclear spent fuel pools. The aim of the present work is to study both laminar and turbulent flow and heat transfer in single-phase natural circulation systems through computational fluid dynamics simulations. The working fluid is considered to be incompressible with constant properties. In the way, the Boussinesq Natural Convection Hypothesis was applied. The model chosen for the turbulence closure problem was the k -- εThe commercial computational fluid dynamics code ANSYS CFX 15.0 was used to obtain the numerical solution of the governing equations. Two single-phase natural circulation circuits were studied, a 2D toroidal loop and a 3D rectangular loop, both with the same boundary conditions of: prescribed heat flux at the heater and fixed wall temperature at the cooler. The validation and verification was performed with the numerical data provided by DESRAYAUD et al. [1] and the experimental data provided by MISALE et al. [2] and KUMAR et al. [3]. An excellent agreement between the Reynolds number (Re) and the modified Grashof number (Gr_m), independently of Prandtl Pr number was observed. However, the convergence interval was observed to be variable with Pr, thus indicating that Pr is a stability governing parameter for natural circulation. Multiple steady states was obtained for Pr = 0,7. Finally, the effect of inclination was studied for the 3D circuit, both in-plane and out-of-plane inclinations were verified for the steady state laminar regime. As a conclusion, the Re for the out-of-plane inclination was in perfect agreement with the correlation found for the zero inclination system, while for the in-plane inclined system the results differ from that of the corresponding vertical loop. (author)

  3. Total robotic radical rectal resection with da Vinci Xi system: single docking, single phase technique.

    Science.gov (United States)

    Tamhankar, Anup Sunil; Jatal, Sudhir; Saklani, Avanish

    2016-12-01

    This study aims to assess the advantages of Da Vinci Xi system in rectal cancer surgery. It also assesses the initial oncological outcomes after rectal resection with this system from a tertiary cancer center in India. Robotic rectal surgery has distinct advantages over laparoscopy. Total robotic resection is increasing following the evolution of hybrid technology. The latest Da Vinci Xi system (Intuitive Surgical, Sunnyvale, USA) is enabled with newer features to make total robotic resection possible with single docking and single phase. Thirty-six patients underwent total robotic resection in a single phase and single docking. We used newer port positions in a straight line. Median distance from the anal verge was 4.5 cm. Median robotic docking time and robotic procedure time were 9 and 280 min, respectively. Median blood loss was 100 mL. One patient needed conversion to an open approach due to advanced disease. Circumferential resection margin and longitudinal resection margins were uninvolved in all other patients. Median lymph node yield was 10. Median post-operative stay was 7 days. There were no intra-operative adverse events. The latest Da Vinci Xi system has made total robotic rectal surgery feasible in single docking and single phase. With the new system, four arm total robotic rectal surgery may replace the hybrid technique of laparoscopic and robotic surgery for rectal malignancies. The learning curve for the new system appears to be shorter than anticipated. Early perioperative and oncological outcomes of total robotic rectal surgery with the new system are promising. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Dimple coalescence and liquid droplets distributions during phase separation in a pure fluid under microgravity.

    Science.gov (United States)

    Oprisan, Ana; Oprisan, Sorinel A; Hegseth, John J; Garrabos, Yves; Lecoutre-Chabot, Carole; Beysens, Daniel

    2014-09-01

    Phase separation has important implications for the mechanical, thermal, and electrical properties of materials. Weightless conditions prevent buoyancy and sedimentation from affecting the dynamics of phase separation and the morphology of the domains. In our experiments, sulfur hexafluoride (SF6) was initially heated about 1K above its critical temperature under microgravity conditions and then repeatedly quenched using temperature steps, the last one being of 3.6 mK, until it crossed its critical temperature and phase-separated into gas and liquid domains. Both full view (macroscopic) and microscopic view images of the sample cell unit were analyzed to determine the changes in the distribution of liquid droplet diameters during phase separation. Previously, dimple coalescences were only observed in density-matched binary liquid mixture near its critical point of miscibility. Here we present experimental evidences in support of dimple coalescence between phase-separated liquid droplets in pure, supercritical, fluids under microgravity conditions. Although both liquid mixtures and pure fluids belong to the same universality class, both the mass transport mechanisms and their thermophysical properties are significantly different. In supercritical pure fluids the transport of heat and mass are strongly coupled by the enthalpy of condensation, whereas in liquid mixtures mass transport processes are purely diffusive. The viscosity is also much smaller in pure fluids than in liquid mixtures. For these reasons, there are large differences in the fluctuation relaxation time and hydrodynamics flows that prompted this experimental investigation. We found that the number of droplets increases rapidly during the intermediate stage of phase separation. We also found that above a cutoff diameter of about 100 microns the size distribution of droplets follows a power law with an exponent close to -2, as predicted from phenomenological considerations.

  5. Beyond the single-file fluid limit using transfer matrix method: Exact results for confined parallel hard squares

    International Nuclear Information System (INIS)

    Gurin, Péter; Varga, Szabolcs

    2015-01-01

    We extend the transfer matrix method of one-dimensional hard core fluids placed between confining walls for that case where the particles can pass each other and at most two layers can form. We derive an eigenvalue equation for a quasi-one-dimensional system of hard squares confined between two parallel walls, where the pore width is between σ and 3σ (σ is the side length of the square). The exact equation of state and the nearest neighbor distribution functions show three different structures: a fluid phase with one layer, a fluid phase with two layers, and a solid-like structure where the fluid layers are strongly correlated. The structural transition between differently ordered fluids develops continuously with increasing density, i.e., no thermodynamic phase transition occurs. The high density structure of the system consists of clusters with two layers which are broken with particles staying in the middle of the pore

  6. Ultrafast Switching Superjunction MOSFETs for Single Phase PFC Applications

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

    2014-01-01

    This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive...... current measurement method, which enables reaching the switching speed limits of these devices. Due to the intrinsic low and non-linear capacitances in vertical SJ MOSFETs, special attention needs to be paid to the gate drive design to minimize oscillations and limit the maximum at turn off. This paper...

  7. Critical flow rate in a single phase flow. Blocking concept

    International Nuclear Information System (INIS)

    Giot, Michel

    1978-01-01

    After referring to the phenomena accompanying the appearance of a critical flow rate in a nozzle and presenting equations governing single phase flows, the critical condition is defined. Several particular cases are then examined; the horizontal and vertical isentropic flow, Fanno's flow and Raleigh's and the isothermal flow. The entropy deviation is calculated on either side of a normal impact. To conclude, the link existing between the concepts of critical flow and the propagation rate of small perturbations is demonstrated. To do so, the method of perturbations, that of Prandtl and that of characteristic directions are applied in turn [fr

  8. Berry-Phase Blockade in Single-Molecule Magnets

    Science.gov (United States)

    González, Gabriel; Leuenberger, Michael N.

    2007-06-01

    We formulate the problem of electron transport through a single-molecule magnet (SMM) in the Coulomb blockade regime taking into account topological interference effects for the tunneling of the large spin of a SMM. The interference originates from spin Berry phases associated with different tunneling paths. We show that, in the case of incoherent spin states, it is essential to place the SMM between oppositely spin-polarized source and drain leads in order to detect the spin tunneling in the stationary current, which exhibits topological zeros as a function of the transverse magnetic field.

  9. Two-phase flow modeling for low concentration spherical particle motion through a Newtonian fluid

    CSIR Research Space (South Africa)

    Smit GJF

    2010-11-01

    Full Text Available the necessity to model the discrete nature of sep- cite this article in press as: G.J.F. Smit et al., Two-phase flow modeling for low concentration spherical particle motion through a ian fluid, Appl. Math. Comput. (2010), doi:10.1016/j.amc.2010.07.055 2... and Ribberin large-scale and long term morphologica Please cite this article in press as: G.J.F. Smit Newtonian fluid, Appl. Math. Comput. (2010), � 2010 Elsevier Inc. All rights reserved. modeling of multiphase flow has increasingly become the subject...

  10. The investigation of a two-layer fluid soliton pair using phase plane analysis

    International Nuclear Information System (INIS)

    Momeni, M.; Moslehi-Fard, M.; Alinejad, H.; Mahmoodi, J.

    2004-01-01

    Nonlinear long waves theory in a two-layer fluid system has been studied. The dynamical equations according to the normalized heights in first order are obtained using the reductive perturbation method and the equations of shallow water in each fluid and taking boundary conditions appropriate into account. Conserve energy form by definition a independent variable is found. By definition a Lyapunov function, the condition for stability are shown. A new technique was used to prove stability as well as existence of soliton pair using phase plane analysis. (author)

  11. Extinction properties of single-walled carbon nanotubes: Two-fluid model

    Energy Technology Data Exchange (ETDEWEB)

    Moradi, Afshin, E-mail: a.moradi@kut.ac.ir [Department of Basic Sciences, Kermanshah University of Technology, Kermanshah, Iran and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran (Iran, Islamic Republic of)

    2014-03-15

    The extinction spectra of a single-walled carbon nanotube are investigated, within the framework of the vector wave function method in conjunction with the hydrodynamic model. Both polarizations of the incident plane wave (TE and TM with respect to the x-z plane) are treated. Electronic excitations on the nanotube surface are modeled by an infinitesimally thin layer of a two-dimensional electron gas represented by two interacting fluids, which takes into account the different nature of the σ and π electrons. Numerical results show that strong interaction between the fluids gives rise to the splitting of the extinction spectra into two peaks in quantitative agreement with the π and σ + π plasmon energies.

  12. An investigation of subchannel analysis models for single-phase and two-phase flow

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Dae Hyun

    1996-01-01

    The governing equations and lateral transport modelings of subchannel analysis code, which is the most widely used tool for the analysis of thermal hydraulics fields in reactor cores, have been thoroughly investigated in this study. The procedure for the derivation of subchannel integral balance equations from the local instantaneous phase equations was investigated by stages. The characteristics of governing equations according to the treatment of phase velocity were studies, and the equations based on the drift-flux equilibrium formulation have been derived. Turbulent mixing and void drift modeling, which affect considerably to the accuracy of subchannel analysis code, have been reviewed. In addition, some representative modelings of single-phase and two-phase turbulent mixing models have been introduced. (author). 5 tabs., 4 figs., 16 refs.

  13. Adaptive nonlinear control of single-phase to three-phase UPS system

    Directory of Open Access Journals (Sweden)

    Kissaoui M.

    2014-01-01

    Full Text Available This work deals with the problems of uninterruptible power supplies (UPS based on the single-phase to three-phase converters built in two stages: an input bridge rectifier and an output three phase inverter. The two blocks are joined by a continuous intermediate bus. The objective of control is threefold: i power factor correction “PFC”, ii generating a symmetrical three-phase system at the output even if the load is unknown, iii regulating the DC bus voltage. The synthesis of controllers has been reached by two nonlinear techniques that are the sliding mode and adaptive backstepping control. The performances of regulators have been validated by numerical simulation in MATLAB / SIMULINK.

  14. Characterization of Single Phase and Two Phase Heat and Momentum Transport in a Spiraling Radial Inow Microchannel Heat Sink

    Science.gov (United States)

    Ruiz, Maritza

    Thermal management of systems under high heat fluxes on the order of hundreds of W/cm2 is important for the safety, performance and lifetime of devices, with innovative cooling technologies leading to improved performance of electronics or concentrating solar photovoltaics. A novel, spiraling radial inflow microchannel heat sink for high flux cooling applications, using a single phase or vaporizing coolant, has demonstrated enhanced heat transfer capabilities. The design of the heat sink provides an inward swirl flow between parallel, coaxial disks that form a microchannel of 1 cm radius and 300 micron channel height with a single inlet and a single outlet. The channel is heated on one side through a conducting copper surface, and is essentially adiabatic on the opposite side to simulate a heat sink scenario for electronics or concentrated photovoltaics cooling. Experimental results on the heat transfer and pressure drop characteristics in the heat sink, using single phase water as a working fluid, revealed heat transfer enhancements due to flow acceleration and induced secondary flows when compared to unidirectional laminar fully developed flow between parallel plates. Additionally, thermal gradients on the surface are small relative to the bulk fluid temperature gain, a beneficial feature for high heat flux cooling applications. Heat flux levels of 113 W/cm2 at a surface temperature of 77 deg C were reached with a ratio of pumping power to heat rate of 0.03%. Analytical models on single phase flow are used to explore the parametric trends of the flow rate and passage geometry on the streamlines and pressure drop through the device. Flow boiling heat transfer and pressure drop characteristics were obtained for this heat sink using water at near atmospheric pressure as the working fluid for inlet subcooling levels ranging from 20 to 80 deg C and mean mass flux levels ranging from 184-716 kg/m. 2s. Flow enhancements similar to singlephase flow were expected, as well

  15. Equilibres de phases dans les systèmes fluides petroliers-eau Phase Equilibria in Oil-Water Systems

    Directory of Open Access Journals (Sweden)

    Peneloux A.

    2006-11-01

    Full Text Available Nous présentons quelques résultats obtenus à partir du logiciel FHYD qui permet le traitement des mélanges eau-fluides pétroliers, avec la détermination de la nature des phases (huile-gaz-eau-hydrate thermodynamiquement stables dans des conditions données de température et de pression, ainsi que de la quantité, de la composition de ces différentes phases et de leurs propriétés. Ce logiciel permet le tracé automatique des diagrammes de phases et nous présentons des exemples, depuis les systèmes binaires (eau-éthane, ternaires (eau-méthane-propane jusqu'aux fluides les plus complexes. La présence de sels (chlorure de sodium dissous est envisagée, ainsi que le calcul des conditions de dépôt du sel solide. Des exemples de problèmes pétroliers sont cités (gaz de séparateur saturé en eau, huile saturée en eau dans les conditions de gisement, huile en présence d'eau salée. Les estimations sur les quantités d'hydrate formées et leurs compositions sont comparées à des données expérimentales et aux résultats obtenus par d'autres logiciels. Le programme FHYD pourrait permettre une représentation plus réaliste de l'évolution des fluides pétroliers et des propriétés de transport de leurs différentes phases dans les modèles de simulation des conduites polyphasiques. This article presents a selection of results obtained with the FHYD program. This software allows simulation of mixtures composed of petroleum fluids and water, with determination of the nature of thermodynamically stable phases (oil-gas-water-hydrate under given conditions of temperature and pressure, along with the quantity, composition and properties of these different phases. Additionally, the program can automatically produce phase diagrams. Several examples of these have been included here, ranging from binary systems (water-ethane and ternary systems (water-methane-propane to the most complex petroleum fluids. The presence of dissolved salts

  16. Differentiating the growth phases of single bacteria using Raman spectroscopy

    Science.gov (United States)

    Strola, S. A.; Marcoux, P. R.; Schultz, E.; Perenon, R.; Simon, A.-C.; Espagnon, I.; Allier, C. P.; Dinten, J.-M.

    2014-03-01

    In this paper we present a longitudinal study of bacteria metabolism performed with a novel Raman spectrometer system. Longitudinal study is possible with our Raman setup since the overall procedure to localize a single bacterium and collect a Raman spectrum lasts only 1 minute. Localization and detection of single bacteria are performed by means of lensfree imaging, whereas Raman signal (from 600 to 3200 cm-1) is collected into a prototype spectrometer that allows high light throughput (HTVS technology, Tornado Spectral System). Accomplishing time-lapse Raman spectrometry during growth of bacteria, we observed variation in the net intensities for some band groups, e.g. amides and proteins. The obtained results on two different bacteria species, i.e. Escherichia coli and Bacillus subtilis clearly indicate that growth affects the Raman chemical signature. We performed a first analysis to check spectral differences and similarities. It allows distinguishing between lag, exponential and stationary growth phases. And the assignment of interest bands to vibration modes of covalent bonds enables the monitoring of metabolic changes in bacteria caused by growth and aging. Following the spectra analysis, a SVM (support vector machine) classification of the different growth phases is presented. In sum this longitudinal study by means of a compact and low-cost Raman setup is a proof of principle for routine analysis of bacteria, in a real-time and non-destructive way. Real-time Raman studies on metabolism and viability of bacteria pave the way for future antibiotic susceptibility testing.

  17. Modelling a single phase voltage controlled rectifier using Laplace transforms

    Science.gov (United States)

    Kraft, L. Alan; Kankam, M. David

    1992-01-01

    The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. It is the intent of this paper to develop a method to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI's HARMFLO program is used as the shell for these models. The results obtained from the model developed in this paper are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented in this paper uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficient of the differential equations which model the line current to the rectifier directly.

  18. Simulation of horizontal pipe two-phase slug flows using the two-fluid model

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Malca, Arturo J. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica. Nucleo de Simulacao Termohidraulica de Dutos (SIMDUT); Nieckele, Angela O. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica

    2005-07-01

    Slug flow occurs in many engineering applications, mainly in the transport of hydrocarbon fluids in pipelines. The intermittency of slug flow causes severe unsteady loading on the pipelines carrying the fluids, which gives rise to design problems. Therefore, it is important to be able to predict the onset and development of slug flow as well as slug characteristics. The present work consists in the simulation of two-phase flow in slug pattern through horizontal pipes using the two-fluid model in its transient and one-dimensional form. The advantage of this model is that the flow field is allowed to develop naturally from a given initial conditions as part of the transient calculation; the slug evolves automatically as a product of the computed flow development. Simulations are then carried out for a large number of flow conditions that lead a slug flow. (author)

  19. Phase-resolved fluid dynamic forces of a flapping foil energy harvester based on PIV measurements

    Science.gov (United States)

    Liburdy, James

    2017-11-01

    Two-dimensional particle image velocimetry measurements are performed in a wind tunnel to evaluate the spatial and temporal fluid dynamic forces acting on a flapping foil operating in the energy harvesting regime. Experiments are conducted at reduced frequencies (k = fc/U) of 0.05 - 0.2, pitching angle of, and heaving amplitude of A / c = 0.6. The phase-averaged pressure field is obtained by integrating the pressure Poisson equation. Fluid dynamic forces are then obtained through the integral momentum equation. Results are compared with a simple force model based on the concept of flow impulse. These results help to show the detailed force distributions, their transient nature and aide in understanding the impact of the fluid flow structures that contribute to the power production.

  20. Preliminary Study of Single-Phase Natural Circulation for Lab-scaled Molten Salt Application

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Yukyung; Kang, Sarah; Kim, In Guk; Seo, Seok Bin; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of); Park, Seong Dae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Advanced reactors such as MSR (FHR), VHTR and AHTR utilized molten salt as a coolant for efficiency and safety which has advantages in higher heat capacity, lower pumping power and scale compared to liquid metal. It becomes more necessary to study on the characteristics of molten salt. However, due to several characteristics such as high operating temperature, large-scale facility and preventing solidification, satisfying that condition for study has difficulties. Thus simulant fluid was used with scaling method for lab-scale experiment. Scaled experiment enables simulant fluid to simulate fluid mechanics and heat transfer behavior of molten salt on lower operating temperature and reduced scale. In this paper, as a proof test of the scaled experiment, simplified single-phase natural circulation loop was designed in a lab-scale and applied to the passive safety system in advanced reactor in which molten salt is considered as a major coolant of the system. For the application of the improved safety system, prototype was based on the primary loop of the test-scale DRACS, the main passive safety system in FHR, developed at the OSU. For preliminary experiment, single-phase natural circulation under low power was performed. DOWTHERM A and DOWTHERM RP were selected as simulant candidates. Then, study of feasibility with simulant was conducted based on the scaling law for heat transfer characteristics and geometric parameters. Additionally, simulation with MARS code and ANSYS-CFX with the same condition of natural circulation was carried out as verification. For the accurate code simulation, thermo-physical properties of DOWTHERM A and RP were developed and implemented into MARS code. In this study, single-phase natural circulation experiment was performed with simulant oil, DOWTHERM RP, based on the passive safety system of FHR. Feasibility of similarity experiment for molten salt with oil simulant was confirmed by scaling method. In addition, simulation with two

  1. Single phase and two-phase flow pressure losses through restrictions, expansions and inserts

    International Nuclear Information System (INIS)

    Glenat, P.; Solignac, P.

    1984-11-01

    We give a selection of methods to predict pressure losses through retrictions, expansions and inserts. In single phase flow, we give the classical method based on the one-dimensional momentum and mass balances. In two-phase flow, we propose the method given by Harshe et al. and an empirical approach suggested by Chisholm. We notice the distinction between long and short inserts depends upon wether or not the vena contracta lies within insert. Finally, we propose three correlations to calculate void fraction through the singularities which have been considered [fr

  2. Single-Phase Phase-Locked Loop Based on Derivative Elements

    DEFF Research Database (Denmark)

    Guan, Qingxin; Zhang, Yu; Kang, Yong

    2017-01-01

    High-performance phase-locked loops (PLLs) are critical for power control in grid-connected systems. This paper presents a new method of designing a PLL for single-phase systems based on derivative elements (DEs). The quadrature signal generator (QSG) is constructed by two DEs with the same...... PLL to achieve high performance when the grid frequency changes rapidly. This paper presents the model of the PLL and a theoretical performance analysis with respect to both the frequency-domain and time-domain behavior. The error arising from the discretization process is also compensated, ensuring...

  3. A Two-Phase Solid/Fluid Model for Dense Granular Flows Including Dilatancy Effects

    Science.gov (United States)

    Mangeney, Anne; Bouchut, Francois; Fernandez-Nieto, Enrique; Narbona-Reina, Gladys

    2015-04-01

    We propose a thin layer depth-averaged two-phase model to describe solid-fluid mixtures such as debris flows. It describes the velocity of the two phases, the compression/dilatation of the granular media and its interaction with the pore fluid pressure, that itself modifies the friction within the granular phase (Iverson et al., 2010). The model is derived from a 3D two-phase model proposed by Jackson (2000) based on the 4 equations of mass and momentum conservation within the two phases. This system has 5 unknowns: the solid and fluid velocities, the solid and fluid pressures and the solid volume fraction. As a result, an additional equation inside the mixture is necessary to close the system. Surprisingly, this issue is inadequately accounted for in the models that have been developed on the basis of Jackson's work (Bouchut et al., 2014). In particular, Pitman and Le replaced this closure simply by imposing an extra boundary condition at the surface of the flow. When making a shallow expansion, this condition can be considered as a closure condition. However, the corresponding model cannot account for a dissipative energy balance. We propose here an approach to correctly deal with the thermodynamics of Jackson's equations. We close the mixture equations by a weak compressibility relation involving a critical density, or equivalently a critical pressure. Moreover, we relax one boundary condition, making it possible for the fluid to escape the granular media when compression of the granular mass occurs. Furthermore, we introduce second order terms in the equations making it possible to describe the evolution of the pore fluid pressure in response to the compression/dilatation of the granular mass without prescribing an extra ad-hoc equation for the pore pressure. We prove that the energy balance associated with this Jackson closure is dissipative, as well as its thin layer associated model. We present several numerical tests for the 1D case that are compared to the

  4. Immiscibility of Fluid Phases at Magmatic-hydrothermal Transition: Formation of Various PGE-sulfide Mineralization for Layered Basic Intrusions

    Science.gov (United States)

    Zhitova, L.; Borisenko, A.; Morgunov, K.; Zhukova, I.

    2007-12-01

    Fluid inclusions in quartz of the Merensky Reef (Bushveld Complex, South Africa) and the Chineisky Pluton (Transbaikal Region, Russia) were studied using cryometry, microthermometry, Raman-spectroscopy, LA ICP- MS, scanning electronic microscopy, gas-chromatography and isotopic methods. This allowed us to document some examples of fluid phase separation resulting in formation of different types of PGE-sulfide mineralization for layered basic intrusions. The results obtained show at least three generations of fluid separated from boiling residual alumosilicate intercumulus liquid of the Merensky Reef. The earliest fluid phase composed of homogenous high-dense methane and nitrogen gas mixture was identified in primary gas and co-existing anomalous fluid inclusions from symplectitic quartz. The next generation, heterophase fluid, composed of brines containing a free low-dense (mostly of carbon dioxide) gas phase, was observed in primary multiphase and coexisting gas-rich inclusions of miarolitic quartz crystals. The latest generation was also a heterophase fluid (low salinity water-salt solution and free low-dense methane gas phase) found in primary water-salt and syngenetic gas inclusions from peripheral zones of miarolitic quartz crystals. For the Chineisky Pluton reduced endocontact magmatogene fluids changed to oxidized low salinity hydrothermal fluids in exocontact zone. This resulted in formation of sulfide-PGE enrichment marginal zones of intrusion. The results obtained give us a possibility to suggest that: 1) Fluid phase separation is a typical feature of magmatogene fluids for layered basic intrusions. 2) Reduced fluids can extract and transport substantial PGE and sulfide concentrations. 3) Oxidation of reduced fluids is one of the most important geochemical barriers causing abundant PGE minerals and sulfides precipitation. This in turn results in both formation of PGE reefs or enriched contact zones of layered basic intrusions. This work was supported by

  5. Ex vivo characterization of pathologic fluids with quantitative phase-contrast computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Vivien, E-mail: vivien.richter@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, Eberhard Karls Universität Tübingen, Hoppe-Seyler-Weg 3, 72076 Tuebingen (Germany); Willner, Marian S., E-mail: marian.willner@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Henningsen, John, E-mail: john.henningsen@tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Birnbacher, Lorenz, E-mail: lorenz.birnbacher@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Marschner, Mathias, E-mail: mathias.marschner@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Herzen, Julia, E-mail: julia.herzen@ph.tum.de [Department of Physics & Institute of Medical Engineering, Technische Universität München, James-Franck-Strasse 1, 85748 Garching (Germany); Kimm, Melanie A., E-mail: melanie.kimm@tum.de [Department of Diagnostic and Interventional Radiology, Technische Universität München, Ismaninger Str. 22, 81675 Munich (Germany); and others

    2017-01-15

    Purpose: X-ray phase-contrast imaging (PCI) provides additional information beyond absorption characteristics by detecting the phase shift of the X-ray beam passing through material. The grating-based system works with standard polychromatic X-ray sources, promising a possible clinical implementation. PCI has been shown to provide additional information in soft-tissue samples. The aim of this study was to determine if ex vivo quantitative phase-contrast computed tomography (PCCT) may differentiate between pathologic fluid collections. Materials and methods: PCCT was performed with the grating interferometry method. A protein serial dilution, human blood samples and 17 clinical samples of pathologic fluid retentions were imaged and correlated with clinical chemistry measurements. Conventional and phase-contrast tomography images were reconstructed. Phase-contrast Hounsfield Units (HUp) were used for quantitative analysis analogously to conventional HU. The imaging was analyzed using overall means, ROI values as well as whole-volume-histograms and vertical gradients. Contrast to noise ratios were calculated between different probes and between imaging methods. Results: HUp showed a very good linear correlation with protein concentration in vitro. In clinical samples, HUp correlated rather well with cell count and triglyceride content. PCI was better than absorption imaging at differentiating protein concentrations in the protein samples as well as at differentiating blood plasma from cellular components. PCI also allowed for differentiation of watery samples (such as lymphoceles) from pus. Conclusion: Phase-contrast computed tomography is a promising tool for the differentiation of pathologic fluids that appear homogenous with conventional attenuation imaging.

  6. US-UK Phase 3 Task 1 Oxidation in Supercritical Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R. [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2017-03-20

    A presentation of the US-UK Phase 3 Task 1 Oxidation in Supercritical Fluids. Includes slides on Supercritical Steam, sCO2 Power Cycles – Indirect, sCO2 Power Cycles – Direct, Experimental Exposures, Alloys, Why Si, Results—Ni-xCr Alloys (5-24Cr), Fatigue Crack Growth$-$Experiment, and Alloys and Samples, Fatigue Crack Growth—Results (H282).

  7. Lattice Boltzmann simulations of liquid crystalline fluids: active gels and blue phases

    OpenAIRE

    Cates, M. E.; Henrich, O.; Marenduzzo, D.; Stratford, K.

    2010-01-01

    Lattice Boltzmann simulations have become a method of choice to solve the hydrodynamic equations of motion of a number of complex fluids. Here we review some recent applications of lattice Boltzmann to study the hydrodynamics of liquid crystalline materials. In particular, we focus on the study of (a) the exotic blue phases of cholesteric liquid crystals, and (b) active gels - a model system for actin plus myosin solutions or bacterial suspensions. In both cases lattice Boltzmann studies have...

  8. Equivalence of two models in single-phase multicomponent flow simulations

    KAUST Repository

    Wu, Yuanqing

    2016-02-28

    In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

  9. Equivalence of two models in single-phase multicomponent flow simulations

    KAUST Repository

    Wu, Yuanqing; Sun, Shuyu

    2016-01-01

    In this work, two models to simulate the single-phase multicomponent flow in reservoirs are introduced: single-phase multicomponent flow model and two-phase compositional flow model. Because the single-phase multicomponent flow is a special case of the two-phase compositional flow, the two-phase compositional flow model can also simulate the case. We compare and analyze the two models when simulating the single-phase multicomponent flow, and then demonstrate the equivalence of the two models mathematically. An experiment is also carried out to verify the equivalence of the two models.

  10. Time domain spectral phase encoding/DPSK data modulation using single phase modulator for OCDMA application.

    Science.gov (United States)

    Wang, Xu; Gao, Zhensen; Kataoka, Nobuyuki; Wada, Naoya

    2010-05-10

    A novel scheme using single phase modulator for simultaneous time domain spectral phase encoding (SPE) signal generation and DPSK data modulation is proposed and experimentally demonstrated. Array- Waveguide-Grating and Variable-Bandwidth-Spectrum-Shaper based devices can be used for decoding the signal directly in spectral domain. The effects of fiber dispersion, light pulse width and timing error on the coding performance have been investigated by simulation and verified in experiment. In the experiment, SPE signal with 8-chip, 20GHz/chip optical code patterns has been generated and modulated with 2.5 Gbps DPSK data using single modulator. Transmission of the 2.5 Gbps data over 34km fiber with BEROCDMA) and secure optical communication applications. (c) 2010 Optical Society of America.

  11. Phase Envelope Calculations for Reservoir Fluids in the Presence of Capillary Pressure

    DEFF Research Database (Denmark)

    Lemus, Diego; Yan, Wei; Michelsen, Michael L.

    2015-01-01

    the bubble and dew point curves but also other quality lines with vapor fractions between 0 and 1. The algorithm has been used to calculate the phase envelopes of binary, multicomponent and reservoir fluid systems for pore radius from 10 to 50 nm. The presence of capillary pressure changes the saturation...... pressures in the whole phase envelope except at the critical point. The bubble point curve shows a negative change while the dew point curve shows positive and negative changes in the upper dew point branch and the lower dew point branch, respectively. In particular, the cricondentherm is also shifted...

  12. Simulating the phosphorus fluid-liquid phase transition up to the critical point

    International Nuclear Information System (INIS)

    Ghiringhelli, Luca M; Meijer, Evert Jan

    2007-01-01

    We report a Car-Parrinello molecular dynamics study of the temperature dependence of the fluid-liquid phase transition in phosphorous, involving the transformation of a molecular fluid phase into a network-like phase. We employed density-functional theory (DFT) with a gradient-corrected functional (B-LYP) to describe the electronic structure and interatomic interactions and performed simulations in a constant pressure ensemble. We spanned a temperature interval ranging from 2500 to 3500 K. With increasing temperature, we found that the structural conversion from the molecular P 4 fluid into the network liquid occurs at decreasing pressures, consistent with experimental observations. At lower temperatures the transition is characterized by a sudden increase of density in the sample. The magnitude of the density change decreases with increasing temperature and vanishes at 3500 K. In the temperature range 3100-3500 K we found signals of near- and super-criticality. We identified local structural changes that serve as seeds triggering the overall structural transition

  13. Simplified paraboloid phase model-based phase tracker for demodulation of a single complex fringe.

    Science.gov (United States)

    He, A; Deepan, B; Quan, C

    2017-09-01

    A regularized phase tracker (RPT) is an effective method for demodulation of single closed-fringe patterns. However, lengthy calculation time, specially designed scanning strategy, and sign-ambiguity problems caused by noise and saddle points reduce its effectiveness, especially for demodulating large and complex fringe patterns. In this paper, a simplified paraboloid phase model-based regularized phase tracker (SPRPT) is proposed. In SPRPT, first and second phase derivatives are pre-determined by the density-direction-combined method and discrete higher-order demodulation algorithm, respectively. Hence, cost function is effectively simplified to reduce the computation time significantly. Moreover, pre-determined phase derivatives improve the robustness of the demodulation of closed, complex fringe patterns. Thus, no specifically designed scanning strategy is needed; nevertheless, it is robust against the sign-ambiguity problem. The paraboloid phase model also assures better accuracy and robustness against noise. Both the simulated and experimental fringe patterns (obtained using electronic speckle pattern interferometry) are used to validate the proposed method, and a comparison of the proposed method with existing RPT methods is carried out. The simulation results show that the proposed method has achieved the highest accuracy with less computational time. The experimental result proves the robustness and the accuracy of the proposed method for demodulation of noisy fringe patterns and its feasibility for static and dynamic applications.

  14. Guidelines for the formulation of Lagrangian stochastic models for particle simulations of single-phase and dispersed two-phase turbulent flows

    Science.gov (United States)

    Minier, Jean-Pierre; Chibbaro, Sergio; Pope, Stephen B.

    2014-11-01

    In this paper, we establish a set of criteria which are applied to discuss various formulations under which Lagrangian stochastic models can be found. These models are used for the simulation of fluid particles in single-phase turbulence as well as for the fluid seen by discrete particles in dispersed turbulent two-phase flows. The purpose of the present work is to provide guidelines, useful for experts and non-experts alike, which are shown to be helpful to clarify issues related to the form of Lagrangian stochastic models. A central issue is to put forward reliable requirements which must be met by Lagrangian stochastic models and a new element brought by the present analysis is to address the single- and two-phase flow situations from a unified point of view. For that purpose, we consider first the single-phase flow case and check whether models are fully consistent with the structure of the Reynolds-stress models. In the two-phase flow situation, coming up with clear-cut criteria is more difficult and the present choice is to require that the single-phase situation be well-retrieved in the fluid-limit case, elementary predictive abilities be respected and that some simple statistical features of homogeneous fluid turbulence be correctly reproduced. This analysis does not address the question of the relative predictive capacities of different models but concentrates on their formulation since advantages and disadvantages of different formulations are not always clear. Indeed, hidden in the changes from one structure to another are some possible pitfalls which can lead to flaws in the construction of practical models and to physically unsound numerical calculations. A first interest of the present approach is illustrated by considering some models proposed in the literature and by showing that these criteria help to assess whether these Lagrangian stochastic models can be regarded as acceptable descriptions. A second interest is to indicate how future

  15. Guidelines for the formulation of Lagrangian stochastic models for particle simulations of single-phase and dispersed two-phase turbulent flows

    International Nuclear Information System (INIS)

    Minier, Jean-Pierre; Chibbaro, Sergio; Pope, Stephen B.

    2014-01-01

    In this paper, we establish a set of criteria which are applied to discuss various formulations under which Lagrangian stochastic models can be found. These models are used for the simulation of fluid particles in single-phase turbulence as well as for the fluid seen by discrete particles in dispersed turbulent two-phase flows. The purpose of the present work is to provide guidelines, useful for experts and non-experts alike, which are shown to be helpful to clarify issues related to the form of Lagrangian stochastic models. A central issue is to put forward reliable requirements which must be met by Lagrangian stochastic models and a new element brought by the present analysis is to address the single- and two-phase flow situations from a unified point of view. For that purpose, we consider first the single-phase flow case and check whether models are fully consistent with the structure of the Reynolds-stress models. In the two-phase flow situation, coming up with clear-cut criteria is more difficult and the present choice is to require that the single-phase situation be well-retrieved in the fluid-limit case, elementary predictive abilities be respected and that some simple statistical features of homogeneous fluid turbulence be correctly reproduced. This analysis does not address the question of the relative predictive capacities of different models but concentrates on their formulation since advantages and disadvantages of different formulations are not always clear. Indeed, hidden in the changes from one structure to another are some possible pitfalls which can lead to flaws in the construction of practical models and to physically unsound numerical calculations. A first interest of the present approach is illustrated by considering some models proposed in the literature and by showing that these criteria help to assess whether these Lagrangian stochastic models can be regarded as acceptable descriptions. A second interest is to indicate how future

  16. Evaluation of the truncated perturbed chain-polar statistical associating fluid theory for complex mixture fluid phase equilibria

    DEFF Research Database (Denmark)

    Karakatsani, Eirini; Kontogeorgis, Georgios; Economou, Ioannis

    2006-01-01

    Perturbed chain-statistical associating fluid theory (PC-SAFT) was extended rigorously to polar fluids based on the theory of Stell and co-workers [Mol. Phys. 1977, 33, 987]. The new PC-PSAFT was simplified to truncated PC-PSAFT (tPC-PSAFT) so that it can be practical for real polar fluid...

  17. MECHANICAL CHARACTERISTICS OF THREE-PHASE INDUCTION MOTORS WITH SINGLE-PHASE POWER SUPPLY

    Directory of Open Access Journals (Sweden)

    V.S. Malyar

    2016-06-01

    Full Text Available Aim. Development of a method for calculating mechanical characteristics of three-phase induction motors with single-phase power supply. Methods. The developed algorithm is based on the high-adequacy mathematical model of motor and projection method for solving the boundary problem for equations of electrical circuits balance presented in the three-phase coordinate system. As a result of asymmetry of power supply to the stator windings, in steady state, flux-linkage and current change according to the periodic law. They are determined by solving the boundary problem. Results. The developed mathematical model allows determining periodic dependence of coordinates as a function of slip and, based on them, mechanical characteristics of motors. Academic novelty. The developed method relies on a completely new mathematical approach to calculation of stationary modes of nonlinear electromagnetic circuits, which allows obtaining periodic solution in a timeless domain. Practical value. Using the developed calculation algorithm, one can select capacitance required to start an induction motor with single-phase power supply and calculate static mechanical characteristics at a given capacitance.

  18. Single Photon Sensitive HgCdTe Avalanche Photodiode Detector (APD), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Leveraging Phase I SBIR successes, in Phase II, a single photon sensitive LIDAR receiver will be fabricated and delivered to NASA. In Phase I, high-gain,...

  19. Dynamics of mineral crystallization at inclusion-garnet interface from precipitated slab-derived fluid phase: first in-situ synchrotron x-ray measurements

    Science.gov (United States)

    Malaspina, Nadia; Alvaro, Matteo; Campione, Marcello; Nestola, Fabrizio

    2015-04-01

    Remnants of the fluid phase at ultrahigh pressure (UHP) in subduction environments may be preserved as primary multiphase inclusions in UHP minerals. These inclusions are frequently hosted by minerals stable at mantle depths, such as garnet, and show the same textural features as fluid inclusions. The mineral infillings of the solid multiphase inclusions are generally assumed to have crystallized by precipitation from the solute load of dense supercritical fluids equilibrating with the host rock. Notwithstanding the validity of this assumption, the mode of crystallization of daughter minerals during precipitation within the inclusion and/or the mechanism of interaction between the fluid at supercritical conditions and the host mineral are still poorly understood from a crystallographic point of view. A case study is represented by garnet orthopyroxenites from the Maowu Ultramafic Complex (China) deriving from harzburgite precursors metasomatised at ~ 4 GPa, 750 °C by a silica- and incompatible trace element-rich fluid phase. This metasomatism produced poikilitic orthopyroxene and inclusion-rich garnet porphyroblasts. Solid multiphase primary inclusions in garnet display a size within a few tens of micrometers and negative crystal shapes. Infilling minerals (spinel: 10-20 vol.%; amphibole, chlorite, talc, mica: 80- 90 vol.%) occur with constant volume ratios and derive from trapped solute-rich aqueous fluids. To constrain the possible mode of precipitation of daughter minerals, we performed for the first time a single-crystal X-ray diffraction experiment by means of Synchrotron Radiation at DLS-Diamond Light Source. In combination with electron probe microanalyses, this measurement allowed the unique identification of each mineral phase and their reciprocal orientations. We demonstrated the epitaxial relationship between spinel and garnet and between some hydrous minerals. Epitaxy drives a first-stage nucleation of spinel under near-to-equilibrium conditions

  20. Structure and single-phase regime of boron carbides

    International Nuclear Information System (INIS)

    Emin, D.

    1988-01-01

    The boron carbides are composed of twelve-atom icosahedral clusters which are linked by direct covalent bonds and through three-atom intericosahedral chains. The boron carbides are known to exist as a single phase with carbon concentrations from about 8 to about 20 at. %. This range of carbon concentrations is made possible by the substitution of boron and carbon atoms for one another within both the icosahedra and intericosahedral chains. The most widely accepted structural model for B 4 C (the boron carbide with nominally 20% carbon) has B/sub 11/C icosahedra with C-B-C intericosahedral chains. Here, the free energy of the boron carbides is studied as a function of carbon concentration by considering the effects of replacing carbon atoms within B 4 C with boron atoms. It is concluded that entropic and energetic considerations both favor the replacement of carbon atoms with boron atoms within the intericosahedral chains, C-B-C→C-B-B. Once the carbon concentration is so low that the vast majority of the chains are C-B-B chains, near B/sub 13/C 2 , subsequent substitutions of carbon atoms with boron atoms occur within the icosahedra, B/sub 11/C→B/sub 12/. Maxima of the free energy occur at the most ordered compositions: B 4 C,B/sub 13/C 2 ,B/sub 14/C. This structural model, determined by studying the free energy, agrees with that previously suggested by analysis of electronic and thermal transport data. These considerations also provide an explanation for the wide single-phase regime found for boron carbides

  1. POD-Galerkin Model for Incompressible Single-Phase Flow in Porous Media

    KAUST Repository

    Wang, Yi

    2017-01-25

    Fast prediction modeling via proper orthogonal decomposition method combined with Galerkin projection is applied to incompressible single-phase fluid flow in porous media. Cases for different configurations of porous media, boundary conditions and problem scales are designed to examine the fidelity and robustness of the model. High precision (relative deviation 1.0 x 10(-4)% similar to 2.3 x 10(-1)%) and large acceleration (speed-up 880 similar to 98454 times) of POD model are found in these cases. Moreover, the computational time of POD model is quite insensitive to the complexity of problems. These results indicate POD model is especially suitable for large-scale complex problems in engineering.

  2. A self-regulating valve for single-phase liquid cooling of microelectronics

    International Nuclear Information System (INIS)

    Donose, Radu; De Volder, Michaël; Peirs, Jan; Reynaerts, Dominiek

    2011-01-01

    This paper reports on the design, optimization and testing of a self-regulating valve for single-phase liquid cooling of microelectronics. Its purpose is to maintain the integrated circuit (IC) at constant temperature and to reduce power consumption by diminishing flow generated by the pump as a function of the cooling requirements. It uses a thermopneumatic actuation principle that combines the advantages of zero power consumption and small size in combination with a high flow rate and low manufacturing costs. The valve actuation is provided by the thermal expansion of a liquid (actuation fluid) which, at the same time, actuates the valve and provides feed-back sensing. A maximum flow rate of 38 kg h −1 passes through the valve for a heat load up to 500 W. The valve is able to reduce the pumping power by up to 60% and it has the capability to maintain the IC at a more uniform temperature.

  3. Numerical simulation of single-phase and multiphase non-Darcy flowin porous and fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yu-Shu

    2000-06-02

    A numerical method as well as a theoretical study of non-Darcy fluid flow of through porous and fractured reservoirs is described. The non-Darcy flow is handled in a three-dimensional, multiphase flow reservoir simulator, while the model formulation incorporates the Forchheimer equation for describing single-phase or multiphase non-Darcy flow and displacement. The numerical scheme has been verified by comparing its results against those of analytical methods. Numerical solutions are used to obtain some insight into the physics of non-Darcy flow and displacement in reservoirs. In addition, several type curves are provided for well-test analyses of non-Darcy flow to demonstrate a methodology for modeling this type of flow in porous and fractured rocks, including flow in geothermal reservoirs.

  4. Prediction of transport phenomena in near and far field: interaction solid phase/fluid phase

    International Nuclear Information System (INIS)

    Mingarro, E.

    1995-01-01

    The prediction of transport phenomena in near and far field is presented in the present report. The study begins with the analysis of solid phases stability: solubility of storage waste: UO 2 and solubility of radionuclides the redox and sorption-desorption conditions are the last aspects studied to predict the transport phenomena

  5. A grid-connected single-phase photovoltaic micro inverter

    Science.gov (United States)

    Wen, X. Y.; Lin, P. J.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.

    2017-11-01

    In this paper, the topology of a single-phase grid-connected photovoltaic (PV) micro-inverter is proposed. The PV micro-inverter consists of DC-DC stage with high voltage gain boost and DC-AC conversion stage. In the first stage, we apply the active clamp circuit and two voltage multipliers to achieve soft switching technology and high voltage gain. In addition, the flower pollination algorithm (FPA) is employed for the maximum power point tracking (MPPT) in the PV module in this stage. The second stage cascades a H-bridge inverter and LCL filter. To feed high quality sinusoidal power into the grid, the software phase lock, outer voltage loop and inner current loop control method are adopted as the control strategy. The performance of the proposed topology is tested by Matlab/Simulink. A PV module with maximum power 300W and maximum power point voltage 40V is applied as the input source. The simulation results indicate that the proposed topology and the control strategy are feasible.

  6. Seismoelectric couplings in a poroelastic material containing two immiscible fluid phases

    Science.gov (United States)

    Jardani, A.; Revil, A.

    2015-08-01

    A new approach of seismoelectric imaging has been recently proposed to detect saturation fronts in which seismic waves are focused in the subsurface to scan its heterogeneous nature and determine saturation fronts. Such type of imaging requires however a complete modelling of the seismoelectric properties of porous media saturated by two immiscible fluid phases, one being usually electrically insulating (for instance water and oil). We combine an extension of Biot dynamic theory, valid for porous media containing two immiscible Newtonian fluids, with an extension of the electrokinetic theory based on the notion of effective volumetric charge densities dragged by the flow of each fluid phase. These effective charge densities can be related directly to the permeability and saturation of each fluid phase. The coupled partial differential equations are solved with the finite element method. We also derive analytically the transfer function connecting the macroscopic electrical field to the acceleration of the fast P wave (coseismic electrical field) and we study the influence of the water content on this coupling. We observe that the amplitude of the co-seismic electrical disturbance is very sensitive to the water content with an increase in amplitude with water saturation. We also investigate the seismoelectric conversions (interface effect) occurring at the water table. We show that the conversion response at the water table can be identifiable only when the saturation contrasts between the vadose and saturated zones are sharp enough. A relatively dry vadose zone represents the best condition to identify the water table through seismoelectric measurements. Indeed, in this case, the coseismic electrical disturbances are vanishingly small compared to the seismoelectric interface response.

  7. Fluid Phase Separation (FPS) experiment for flight on the shuttle in a Get Away Special (GAS) canister: Design and fabrication

    Science.gov (United States)

    1990-01-01

    The separation of fluid phases in microgravity environments is of importance to environmental control and life support systems (ECLSS) and materials processing in space. A successful fluid phase separation experiment will demonstrate a proof of concept for the separation technique and add to the knowledge base of material behavior. The phase separation experiment will contain a premixed fluid that will be exposed to a microgravity environment. After the phase separation of the compound has occurred, small samples of each of the species will be taken for analysis on Earth. By correlating the time of separation and the temperature history of the fluid, it will be possible to characterize the process. The phase separation experiment is totally self-contained, with three levels of containment on all fluids, and provides all necessary electrical power and control. The controller regulates the temperature of the fluid and controls data logging and sampling. An astronaut-activated switch will initiate the experiment and an unmaskable interrupt is provided for shutdown. The experiment has been integrated into space available on a manifested Get Away Special (GAS) experiment, CONCAP 2, part of the Consortium for Materials Complex Autonomous Payload (CAP) Program, scheduled for STS 42 in April 1991. Presented here are the design and the production of a fluid phase separation experiment for rapid implementation at low cost.

  8. Modeling mechanical properties of a shear thickening fluid damper based on phase transition theory

    Science.gov (United States)

    Wei, Minghai; Lin, Kun; Guo, Qian

    2018-03-01

    Shear thickening fluids (STFs) are highly concentrated colloidal suspensions consisting of monodisperse nano-particles suspended in a carrying fluid, and have the capacity to display both flowable and rigid behaviors, when subjected to sudden stimuli. In that process, the external energy that acts on an STF can be dissipated quickly. The aim of this study is to present a dynamic model of a damper filled with STF that can be directly used in control engineering fields. To this end, shear stress during phase transition of the STF material is chosen as an internal variable. A non-convex function with bifurcation behavior is used to describe the phase transitioning of STF by determining the relationship between the behavioral characteristics of the microscopic phase and macroscopic damping force. This model is able to predict force-velocity and force-displacement relationships as functions of the loading frequency. Efficacy of the model is demonstrated via comparison with experimental results from previous studies. In addition, the results confirm the hypothesis regarding the occurrence of STF phase transitioning when subject to shear stress.

  9. 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.

  10. Analysis of flow induced valve operation and pressure wave propagation for single and two-phase flow conditions

    International Nuclear Information System (INIS)

    Nagel, H.

    1986-01-01

    The flow induced valve operation is calculated for single and two-phase flow conditions by the fluid dynamic computer code DYVRO and results are compared to experimental data. The analysis show that the operational behaviour of the valves is not only dependent on the condition of the induced flow, but also the pipe flow can cause a feedback as a result of the induced pressure waves. For the calculation of pressure wave propagation in pipes of which the operation of flow induced valves has a considerable influence it is therefore necessary to have a coupled analysis of the pressure wave propagation and the operational behaviour of the valves. The analyses of the fast transient transfer from steam to two-phase flow show a good agreement with experimental data. Hence even these very high loads on pipes resulting from such fluid dynamic transients can be calculated realistically. (orig.)

  11. Experimental studies in a single-phase parallel channel natural circulation system. Preliminary results

    International Nuclear Information System (INIS)

    Bodkha, Kapil; Pilkhwal, D.S.; Jana, S.S.; Vijayan, P.K.

    2016-01-01

    Natural circulation systems find extensive applications in industrial engineering systems. One of the applications is in nuclear reactor where the decay heat is removed by natural circulation of the fluid under off-normal conditions. The upcoming reactor designs make use of natural circulation in order to remove the heat from core under normal operating conditions also. These reactors employ multiple vertical fuel channels with provision of on-power refueling/defueling. Natural circulation systems are relatively simple, safe and reliable when compared to forced circulation systems. However, natural circulation systems are prone to encounter flow instabilities which are highly undesirable for various reasons. Presence of parallel channels under natural circulation makes the system more complicated. To examine the behavior of parallel channel system, studies were carried out for single-phase natural circulation flow in a multiple vertical channel system. The objective of the present work is to study the flow behavior of the parallel heated channel system under natural circulation for different operating conditions. Steady state and transient studies have been carried out in a parallel channel natural circulation system with three heated channels. The paper brings out the details of the system considered, different cases analyzed and preliminary results of studies carried out on a single-phase parallel channel system.

  12. Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

    Science.gov (United States)

    Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

    2018-04-01

    To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

  13. Enantioselective potential of polysaccharide-based chiral stationary phases in supercritical fluid chromatography.

    Science.gov (United States)

    Kucerova, Gabriela; Kalikova, Kveta; Tesarova, Eva

    2017-06-01

    The enantioselective potential of two polysaccharide-based chiral stationary phases for analysis of chiral structurally diverse biologically active compounds was evaluated in supercritical fluid chromatography using a set of 52 analytes. The chiral selectors immobilized on 2.5 μm silica particles were tris-(3,5-dimethylphenylcarmabate) derivatives of cellulose or amylose. The influence of the polysaccharide backbone, different organic modifiers, and different mobile phase additives on retention and enantioseparation was monitored. Conditions for fast baseline enantioseparation were found for the majority of the compounds. The success rate of baseline and partial enantioseparation with cellulose-based chiral stationary phase was 51.9% and 15.4%, respectively. Using amylose-based chiral stationary phase we obtained 76.9% of baseline enantioseparations and 9.6% of partial enantioseparations of the tested compounds. The best results on cellulose-based chiral stationary phase were achieved particularly with propane-2-ol and a mixture of isopropylamine and trifluoroacetic acid as organic modifier and additive to CO 2 , respectively. Methanol and basic additive isopropylamine were preferred on amylose-based chiral stationary phase. The complementary enantioselectivity of the cellulose- and amylose-based chiral stationary phases allows separation of the majority of the tested structurally different compounds. Separation systems were found to be directly applicable for analyses of biologically active compounds of interest. © 2017 Wiley Periodicals, Inc.

  14. Near-optimality of special periodic protocols for fluid models of single server switched networks with switchover times

    Science.gov (United States)

    Matveev, A. S.; Ishchenko, R.

    2017-11-01

    We consider a generic deterministic time-invariant fluid model of a single server switched network, which consists of finitely many infinite size buffers (queues) and receives constant rate inflows of jobs from the outside. Any flow undergoes a multi-phase service, entering a specific buffer after every phase, and ultimately leaves the network; the route of the flow over the buffers is pre-specified, and flows may merge inside the network. They share a common source of service, which can serve at most one buffer at a time and has to switch among buffers from time to time; any switch consumes a nonzero switchover period. With respect to the long-run maximal scaled wip (work in progress) performance metric, near-optimality of periodic scheduling and service protocols is established: the deepest optimum (that is over all feasible processes in the network, irrespective of the initial state) is furnished by such a protocol up to as small error as desired. Moreover, this can be achieved with a special periodic protocol introduced in the paper. It is also shown that the exhaustive policy is optimal for any buffer whose service at the maximal rate does not cause growth of the scaled wip.

  15. Phase-space analysis of the cosmological 3-fluid problem: families of attractors and repellers

    International Nuclear Information System (INIS)

    Azreg-Aïnou, Mustapha

    2013-01-01

    We perform a phase-space analysis of the cosmological 3-fluid problem consisting of a barotropic fluid with an equation-of-state parameter γ − 1, a pressureless dark matter fluid, plus a scalar field ϕ (representing dark energy) coupled to an exponential potential V = V 0 exp ( − κλϕ). Besides the potential–kinetic scaling solutions, which are not the unique late-time attractors whenever they exist for λ 2 ⩾ 3γ, we derive new attractors where both dark energy and dark matter coexist and the final density is shared in a way independent of the value of γ > 1. The case of a pressureless barotropic fluid (γ = 1) has a one-parameter family of attractors where all components coexist. New one-parameter families of matter–dark matter saddle points and kinetic–matter repellers exist. We investigate the stability of the ten critical points by linearization and/or Lyapunov's theorems and a variant of the theorems formulated in this paper. A solution with two transient periods of acceleration and two transient periods of deceleration is derived. (paper)

  16. Conditions and phase shift of fluid resonance in narrow gaps of bottom mounted caissons

    Science.gov (United States)

    Zhu, Da-tong; Wang, Xing-gang; Liu, Qing-jun

    2017-12-01

    This paper studies the viscid and inviscid fluid resonance in gaps of bottom mounted caissons on the basis of the plane wave hypothesis and full wave model. The theoretical analysis and the numerical results demonstrate that the condition for the appearance of fluid resonance in narrow gaps is kh=(2 n+1)π ( n=0, 1, 2, 3, …), rather than kh= nπ ( n=0, 1, 2, 3, …); the transmission peaks in viscid fluid are related to the resonance peaks in the gaps. k and h stand for the wave number and the gap length. The combination of the plane wave hypothesis or the full wave model with the local viscosity model can accurately determine the heights and the locations of the resonance peaks. The upper bound for the appearance of fluid resonance in gaps is 2 b/ Lreason for the phase shift of the resonance peaks is the inductive factors. The number of resonance peaks in the spectrum curve is dependent on the ratio of the gap length to the grating constant. The heights and the positions of the resonance peaks predicted by the present models agree well with the experimental data.

  17. Thermal Marangoni convection in two-phase flow of dusty Casson fluid

    Science.gov (United States)

    Mahanthesh, B.; Gireesha, B. J.

    2018-03-01

    This paper deals with the thermal Marangoni convection effects in magneto-Casson liquid flow through suspension of dust particles. The transpiration cooling aspect is accounted. The surface tension is assumed to be fluctuating linearly with temperature. The fluid and dust particle's temperature of the interface is chosen as a quadratic function of interface arc length. The governing problem is modelled by conservation laws of mass, momentum and energy for fluid and dust particle phase. Stretching transformation technique is utilized to form ordinary differential equations from the partial differential equations. Later, the numerical solutions based on Runge-Kutta-Fehlberg method are established. The momentum and heat transport distributions are focused on the outcome of distinct governing parameters. The results of Nusselt number is also presented and discussed. It is established that the heat transfer rate is higher in the case of dusty non-Newtonian fluid than dusty Newtonian fluid. The rate of heat transfer can be enhanced by suspending dust particles in a base liquid.

  18. Phase behavior of the modified-Yukawa fluid and its sticky limit.

    Science.gov (United States)

    Schöll-Paschinger, Elisabeth; Valadez-Pérez, Néstor E; Benavides, Ana L; Castañeda-Priego, Ramón

    2013-11-14

    Simple model systems with short-range attractive potentials have turned out to play a crucial role in determining theoretically the phase behavior of proteins or colloids. However, as pointed out by D. Gazzillo [J. Chem. Phys. 134, 124504 (2011)], one of these widely used model potentials, namely, the attractive hard-core Yukawa potential, shows an unphysical behavior when one approaches its sticky limit, since the second virial coefficient is diverging. However, it is exactly this second virial coefficient that is typically used to depict the experimental phase diagram for a large variety of complex fluids and that, in addition, plays an important role in the Noro-Frenkel scaling law [J. Chem. Phys. 113, 2941 (2000)], which is thus not applicable to the Yukawa fluid. To overcome this deficiency of the attractive Yukawa potential, D. Gazzillo has proposed the so-called modified hard-core attractive Yukawa fluid, which allows one to correctly obtain the second and third virial coefficients of adhesive hard-spheres starting from a system with an attractive logarithmic Yukawa-like interaction. In this work we present liquid-vapor coexistence curves for this system and investigate its behavior close to the sticky limit. Results have been obtained with the self-consistent Ornstein-Zernike approximation (SCOZA) for values of the reduced inverse screening length parameter up to 18. The accuracy of SCOZA has been assessed by comparison with Monte Carlo simulations.

  19. Microtomography and pore-scale modeling of two-phase Fluid Distribution

    Energy Technology Data Exchange (ETDEWEB)

    Silin, D.; Tomutsa, L.; Benson, S.; Patzek, T.

    2010-10-19

    Synchrotron-based X-ray microtomography (micro CT) at the Advanced Light Source (ALS) line 8.3.2 at the Lawrence Berkeley National Laboratory produces three-dimensional micron-scale-resolution digital images of the pore space of the reservoir rock along with the spacial distribution of the fluids. Pore-scale visualization of carbon dioxide flooding experiments performed at a reservoir pressure demonstrates that the injected gas fills some pores and pore clusters, and entirely bypasses the others. Using 3D digital images of the pore space as input data, the method of maximal inscribed spheres (MIS) predicts two-phase fluid distribution in capillary equilibrium. Verification against the tomography images shows a good agreement between the computed fluid distribution in the pores and the experimental data. The model-predicted capillary pressure curves and tomography-based porosimetry distributions compared favorably with the mercury injection data. Thus, micro CT in combination with modeling based on the MIS is a viable approach to study the pore-scale mechanisms of CO{sub 2} injection into an aquifer, as well as more general multi-phase flows.

  20. Flow regime classification in air-magnetic fluid two-phase flow.

    Science.gov (United States)

    Kuwahara, T; De Vuyst, F; Yamaguchi, H

    2008-05-21

    A new experimental/numerical technique of classification of flow regimes (flow patterns) in air-magnetic fluid two-phase flow is proposed in the present paper. The proposed technique utilizes the electromagnetic induction to obtain time-series signals of the electromotive force, allowing us to make a non-contact measurement. Firstly, an experiment is carried out to obtain the time-series signals in a vertical upward air-magnetic fluid two-phase flow. The signals obtained are first treated using two kinds of wavelet transforms. The data sets treated are then used as input vectors for an artificial neural network (ANN) with supervised training. In the present study, flow regimes are classified into bubbly, slug, churn and annular flows, which are generally the main flow regimes. To validate the flow regimes, a visualization experiment is also performed with a glycerin solution that has roughly the same physical properties, i.e., kinetic viscosity and surface tension, as a magnetic fluid used in the present study. The flow regimes from the visualization are used as targets in an ANN and also used in the estimation of the accuracy of the present method. As a result, ANNs using radial basis functions are shown to be the most appropriate for the present classification of flow regimes, leading to small classification errors.

  1. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings, phase 2

    Science.gov (United States)

    Sanandres, Luis

    1994-01-01

    The Phase 2 (1994) Annual Progress Report presents two major report sections describing the thermal analysis of tilting- and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings. A literature review on the subject of two-phase flow in fluid film bearings and part of the proposed work for 1995 are also included. The programs delivered at the end of 1994 are named hydroflext and hydrotran. Both codes are fully compatible with the hydrosealt (1993) program. The new programs retain the same calculating options of hydrosealt plus the added bearing geometries, and unsteady flow and transient forced response. Refer to the hydroflext & hydrotran User's Manual and Tutorial for basic information on the analysis and instructions to run the programs. The Examples Handbook contains the test bearing cases along with comparisons with experimental data or published analytical values. The following major tasks were completed in 1994 (Phase 2): (1) extension of the thermohydrodynamic analysis and development of computer program hydroflext to model various bearing geometries, namely, tilting-pad hydrodynamic journal bearings, flexure-pad cylindrical bearings (hydrostatic and hydrodynamic), and cylindrical pad bearings with a simple elastic matrix (ideal foil bearings); (2) improved thermal model including radial heat transfer through the bearing stator; (3) calculation of the unsteady bulk-flow field in fluid film bearings and the transient response of a point mass rotor supported on bearings; and (4) a literature review on the subject of two-phase flows and homogeneous-mixture flows in thin-film geometries.

  2. MR phase imaging and cerebrospinal fluid flow in the head and spine

    International Nuclear Information System (INIS)

    Levy, L.M.; Di Chiro, G.

    1990-01-01

    Motion of the cerebrospinal fluid (CSF) in and around the brain spinal cord was examined in healthy subjects and in a number of patients with abnormalities of the CSF circulation. The pulsatile motion of the CSF was determined by spin echo phase (velocity) imaging, sometimes in combination with gradient echo phase contrast cine. Differences in flow patterns across CSF spaces were observed: Flow reversal in the cerebellomedullary cistern and lumbar area relative to cervical CSF, and in the posterior versus the anterior subarachnoid space in the spinal canal. Flow communication was demonstrated in known communicating cysts or cavities. Differences in flow were also noted across spinal narrowing or block, and across the walls of a variety of cystic lesions in the brain and spinal cord. MR phase imaging of CSF flow provides pathophysiological information of potential clinical importance for the assessment of diseases affecting the CSF circulation. (orig.)

  3. Nonequilibrium phase transitions, fluctuations and correlations in an active contractile polar fluid.

    Science.gov (United States)

    Gowrishankar, Kripa; Rao, Madan

    2016-02-21

    We study the patterning, fluctuations and correlations of an active polar fluid consisting of contractile polar filaments on a two-dimensional substrate, using a hydrodynamic description. The steady states generically consist of arrays of inward pointing asters and show a continuous transition from a moving lamellar phase, a moving aster street, to a stationary aster lattice with no net polar order. We next study the effect of spatio-temporal athermal noise, parametrized by an active temperature TA, on the stability of the ordered phases. In contrast to its equilibrium counterpart, we find that the active crystal shows true long range order at low TA. On increasing TA, the asters dynamically remodel, concomitantly we find novel phase transitions characterized by bond-orientational and polar order upon "heating".

  4. Poly(butylene terephthalate) based novel achiral stationary phase investigated under supercritical fluid chromatography conditions.

    Science.gov (United States)

    Nagai, Kanji; Shibata, Tohru; Shinkura, Satoshi; Ohnishi, Atsushi

    2018-05-11

    Poly(butylene terephthalate) based novel stationary phase (SP), composed of planar aromatic phenyl group together with ester group monomer units, was designed for supercritical fluid chromatography (SFC) use. As expected from its structure, this phase shows planarity recognition of isomeric aromatics and closely similar compounds. Interestingly, for most analytes, the retention behavior of this SP is significantly distinct from that of the 2-ethylpyridine based SPs which is among the most well-known SFC dedicated phases. Although the poly(butylene terephthalate) is coated on silica gel, the performance of the column did not change by using extended range modifiers such as THF, dichloromethane or ethyl acetate and column robustness was confirmed by cycle durability testing. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  5. Analytical prediction of the electromagnetic torques in single-phase and two-phase ac motors

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, M.

    2004-07-01

    The single-phase and two-phase versions of AC motors can be modelled by means of the two-axis (d-q) theory with sufficient accuracy when the equivalent circuit parameters are correctly estimated. This work attempts to present a unified approach to the analytical prediction of the electromagnetic torque of these machines. Classical d-q axes formulation requires that the reference frame should be fixed on the frame where the asymmetries arise, i.e. the stator and rotor. The asynchronous torques that characterize the induction motors are modelled in a stationary reference frame, where the d-q axes coincide with the physical magnetic axes of the stator windings. For the permanent magnet motors, that may exhibit asymmetries on both stator and rotor, the proposed solution includes: a series of frame transformations, followed by symmetrical components decomposition. As in single-phase and two-phase systems the homopolar component is zero; each symmetrical component - negative and positive - is further analysed using d-q axes theory. The superposition principle is employed to consider the magnets and rotor cage effects. The developed models account for the most important asymmetries of the motor configuration. These are, from the stator point of view, different distribution, conductors' dimensions and number of effective turns, non-orthogonal magnetic axes windings and from the rotor point of view, asymmetrical rotor cage, variable reluctance, and permanent magnets effect. The time and space harmonics effect is ignored. Test data are compared with the computed data in order to observe how the simplifying assumptions affect the level of accuracy. The analytical prediction methods make possible torque computation according to the nature of the torque being computed, namely, induction, reluctance and excitation (permanent magnet). The results are available for quasi steady-state, steady-state (rated or synchronous speed) and dynamic analyses. All the developed

  6. Two-Phase Fluid Simulation Using a Diffuse Interface Model with Peng--Robinson Equation of State

    KAUST Repository

    Qiao, Zhonghua; Sun, Shuyu

    2014-01-01

    In this paper, two-phase fluid systems are simulated using a diffusive interface model with the Peng-Robinson equation of state (EOS), a widely used realistic EOS for hydrocarbon fluid in the petroleum industry. We first utilize the gradient theory

  7. Analysis and Design Tools for Fluid-Structure Interaction with Multi-Body Flexible Structures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of this proposal (Phases I and II) is to develop a robust and accurate solver for fluid-structure interaction computations capable of...

  8. Comparison of twin-fluid atomizers using a phase Doppler analyser

    Energy Technology Data Exchange (ETDEWEB)

    Zaremba, Matouš, E-mail: y116215@stud.fme.vutbr.cz, E-mail: y145527@stud.fme.vutbr.cz, E-mail: jedelsky@fme.vutbr.cz, E-mail: jicha@fme.vutbr.cz; Malý, Milan, E-mail: y116215@stud.fme.vutbr.cz, E-mail: y145527@stud.fme.vutbr.cz, E-mail: jedelsky@fme.vutbr.cz, E-mail: jicha@fme.vutbr.cz; Jedelský, Jan, E-mail: y116215@stud.fme.vutbr.cz, E-mail: y145527@stud.fme.vutbr.cz, E-mail: jedelsky@fme.vutbr.cz, E-mail: jicha@fme.vutbr.cz; Jícha, Miroslav, E-mail: y116215@stud.fme.vutbr.cz, E-mail: y145527@stud.fme.vutbr.cz, E-mail: jedelsky@fme.vutbr.cz, E-mail: jicha@fme.vutbr.cz [Brno University of technology, Technická 2896/2, 616 69 Brno (Czech Republic)

    2014-08-06

    The quality of atomization is crucial in combustion processes, especially in cases of highly viscous fuels. Twin-fluid atomizers have been developed for atomizing heavy and waste fuels and they have undergone significant development in the last decades. Nevertheless, in order to design an atomizer for a given industrial application, a comparison of different atomizers at similar operating conditions is required. This paper focuses on the description and comparison of two internally mixed twin-fluid atomizers at the same operating regime. The Y-jet and the Inverse-effervescent atomizers were examined. The phase-Doppler analyzer was used to measure the velocity and size of droplets in a radial profile in the spray. Data were sorted out into classes with respect to the droplet size and the motion analysis was done for both atomizers.

  9. Single-bubble dynamics in pool boiling of one-component fluids

    KAUST Repository

    Xu, Xinpeng; Qian, Tiezheng

    2014-01-01

    We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-bubble dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for bubbles on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the bubble spreading over the heating surface and increase the bubble departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of bubbles on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of bubble nucleation while the surrounding hydrophilic region hinders the continuous bubble spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small bubble departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the bubble nucleation probability increased and the bubble departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013)]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.

  10. Single-bubble dynamics in pool boiling of one-component fluids

    KAUST Repository

    Xu, Xinpeng

    2014-06-04

    We numerically investigate the pool boiling of one-component fluids with a focus on the effects of surface wettability on the single-bubble dynamics. We employed the dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)], a diffuse-interface model for liquid-vapor flows involving liquid-vapor transition in nonuniform temperature fields. We first perform simulations for bubbles on homogeneous surfaces. We find that an increase in either the contact angle or the surface superheating can enhance the bubble spreading over the heating surface and increase the bubble departure diameter as well and therefore facilitate the transition into film boiling. We then examine the dynamics of bubbles on patterned surfaces, which incorporate the advantages of both hydrophobic and hydrophilic surfaces. The central hydrophobic region increases the thermodynamic probability of bubble nucleation while the surrounding hydrophilic region hinders the continuous bubble spreading by pinning the contact line at the hydrophobic-hydrophilic intersection. This leads to a small bubble departure diameter and therefore prevents the transition from nucleate boiling into film boiling. With the bubble nucleation probability increased and the bubble departure facilitated, the efficiency of heat transfer on such patterned surfaces is highly enhanced, as observed experimentally [Int. J. Heat Mass Transfer 57, 733 (2013)]. In addition, the stick-slip motion of contact line on patterned surfaces is demonstrated in one-component fluids, with the effect weakened by surface superheating.

  11. Analysis of the two-fluid model in fully-developed two-phase flow

    International Nuclear Information System (INIS)

    Azpitarte, Osvaldo Enrique

    2003-01-01

    The two fluid model is analysed and applied to solve vertical fully-developed bubbly two-phase flows, both in laminar and turbulent conditions.The laminar model is reduced to two differential equations to solve the gas fraction (ε G ) and the velocity (υ L ).For the turbulent condition, a k - ε model for low Reynolds number is implemented, resulting in a set of differential equations to solve the four variables (ε G , υ L , k and ε) along the whole radial domain (including the laminar sub layer).For laminar condition, the system is initially reduced to a single non-dimensional ordinary equation (O D E) to solve ε G in the central region of the duct, without considering the effect of the wall.The equation is solved using Mathematic a.Analysing the solutions it can be concluded that an exact compensation of the applied pressure gradient with the hydrostatic force ρ e ff g occurs (ρ e ff : effective density of the mixture).This compensation implies that the value of ε G at the center of the duct only depends on the applied pressure gradient (dependency is linear), and that the ε G and υ L profiles are necessarily fl ato The complete problem is dealt numerically through the implementation of a finite element co deo The effect of the walls is included via a model of wall force.When the code is applied to a laminar condition, the conclusions previously obtained solving the O D E are confirmed.It is also possible to analyse the regime in which the pressure gradient is greater than the weight of the pure liquid, in which case a region of strictly zero void fraction develops surrounding the axis of the duct (in upward flow).When the code is applied to a turbulent condition, it is shown that the conclusions obtained for laminar condition can also be applied, but within a range of pressure gradient limited by two transition values (θ 1 and θ 2 ).An analysis of transitions θ 1 and θ 2 allows u s to conclude that their origin is a sudden increase of lateral

  12. Evaluation of single and stack membraneless enzymatic fuel cells based on ethanol in simulated body fluids.

    Science.gov (United States)

    Galindo-de-la-Rosa, J; Arjona, N; Moreno-Zuria, A; Ortiz-Ortega, E; Guerra-Balcázar, M; Ledesma-García, J; Arriaga, L G

    2017-06-15

    The purpose of this work is to evaluate single and double-cell membraneless microfluidic fuel cells (MMFCs) that operate in the presence of simulated body fluids SBF, human serum and blood enriched with ethanol as fuels. The study was performed using the alcohol dehydrogenase enzyme immobilised by covalent binding through an array composed of carbon Toray paper as support and a layer of poly(methylene blue)/tetrabutylammonium bromide/Nafion and glutaraldehyde (3D bioanode electrode). The single MMFC was tested in a hybrid microfluidic fuel cell using Pt/C as the cathode. A cell voltage of 1.035V and power density of 3.154mWcm -2 were observed, which is the highest performance reported to date. The stability and durability were tested through chronoamperometry and polarisation/performance curves obtained at different days, which demonstrated a slow decrease in the power density on day 10 (14%) and day 20 (26%). Additionally, the cell was tested for ethanol oxidation in simulated body fluid (SBF) with ionic composition similar to human blood plasma. Those tests resulted in 0.93V of cell voltage and a power density close to 1.237mWcm -2 . The double cell MMFC (Stack) was tested using serum and human blood enriched with ethanol. The stack operated with blood in a serial connection showed an excellent cell performance (0.716mWcm -2 ), demonstrating the feasibility of employing human blood as energy source. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Single particle detection: Phase control in submicron Hall sensors

    International Nuclear Information System (INIS)

    Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga

    2010-01-01

    We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≅10 8 μ B has been achieved with a 600 nm-wide sensor.

  14. Self-assembled single-phase perovskite nanocomposite thin films.

    Science.gov (United States)

    Kim, Hyun-Suk; Bi, Lei; Paik, Hanjong; Yang, Dae-Jin; Park, Yun Chang; Dionne, Gerald F; Ross, Caroline A

    2010-02-10

    Thin films of perovskite-structured oxides with general formula ABO(3) have great potential in electronic devices because of their unique properties, which include the high dielectric constant of titanates, (1) high-T(C) superconductivity in cuprates, (2) and colossal magnetoresistance in manganites. (3) These properties are intimately dependent on, and can therefore be tailored by, the microstructure, orientation, and strain state of the film. Here, we demonstrate the growth of cubic Sr(Ti,Fe)O(3) (STF) films with an unusual self-assembled nanocomposite microstructure consisting of (100) and (110)-oriented crystals, both of which grow epitaxially with respect to the Si substrate and which are therefore homoepitaxial with each other. These structures differ from previously reported self-assembled oxide nanocomposites, which consist either of two different materials (4-7) or of single-phase distorted-cubic materials that exhibit two or more variants. (8-12) Moreover, an epitaxial nanocomposite SrTiO(3) overlayer can be grown on the STF, extending the range of compositions over which this microstructure can be formed. This offers the potential for the implementation of self-organized optical/ferromagnetic or ferromagnetic/ferroelectric hybrid nanostructures integrated on technologically important Si substrates with applications in magnetooptical or spintronic devices.

  15. SINGLE PHASE ANALYTICAL MODELS FOR TERRY TURBINE NOZZLE

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Haihua; Zhang, Hongbin; Zou, Ling; O' Brien, James

    2016-11-01

    All BWR RCIC (Reactor Core Isolation Cooling) systems and PWR AFW (Auxiliary Feed Water) systems use Terry turbine, which is composed of the wheel with turbine buckets and several groups of fixed nozzles and reversing chambers inside the turbine casing. The inlet steam is accelerated through the turbine nozzle and impacts on the wheel buckets, generating work to drive the RCIC pump. As part of the efforts to understand the unexpected “self-regulating” mode of the RCIC systems in Fukushima accidents and extend BWR RCIC and PWR AFW operational range and flexibility, mechanistic models for the Terry turbine, based on Sandia National Laboratories’ original work, has been developed and implemented in the RELAP-7 code to simulate the RCIC system. RELAP-7 is a new reactor system code currently under development with the funding support from U.S. Department of Energy. The RELAP-7 code is a fully implicit code and the preconditioned Jacobian-free Newton-Krylov (JFNK) method is used to solve the discretized nonlinear system. This paper presents a set of analytical models for simulating the flow through the Terry turbine nozzles when inlet fluid is pure steam. The implementation of the models into RELAP-7 will be briefly discussed. In the Sandia model, the turbine bucket inlet velocity is provided according to a reduced-order model, which was obtained from a large number of CFD simulations. In this work, we propose an alternative method, using an under-expanded jet model to obtain the velocity and thermodynamic conditions for the turbine bucket inlet. The models include both adiabatic expansion process inside the nozzle and free expansion process out of the nozzle to reach the ambient pressure. The combined models are able to predict the steam mass flow rate and supersonic velocity to the Terry turbine bucket entrance, which are the necessary input conditions for the Terry Turbine rotor model. The nozzle analytical models were validated with experimental data and

  16. On heat transfer to pulsatile flow of a two-phase fluid

    Directory of Open Access Journals (Sweden)

    S. P. Chakraborty

    2005-09-01

    Full Text Available The problem of heat transfer to pulsatile flow of a two-phase fluid-particle system contained in a channel bounded by two infinitely long rigid impervious parallel walls has been studied in this paper. The solutions for the steady and the fluctuating temperature distributions are obtained. The rates of heat transfer at the walls are also calculated. The results are discussed numerically with graphical presentations. It is shown that the presence of the particles not only diminishes the steady and unsteady temperature fields but also decreases the reversal of heat flux at the hotter wall irrespective of the influences of other flow parameters.

  17. Parametric numerical investigaion of natural convection in a heat-generating fluid with phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Aksenova, A.E.; Chudanov, V.V.; Strizhov, V.F.; Vabishchevich, P.N. [Institute of Nuclear Safety Russian Academy Science, Moscow (Russian Federation)

    1995-09-01

    Unsteady natural convection of a heat-generating fluid with phase transitions in the enclosures of a square section with isothermal rigid walls is investigated numerically for a wide range of dimensionless parameters. The quasisteady state solutions of conjugate heat and mass transfer problem are compared with available experimental results. Correlation relations for heat flux distributions at the domain boundaries depending on Rayleigh and Ostrogradskii numbers are obtained. It is shown that generally heat transfer is governed both by natural circulation and crust formation phenomena. Results of this paper may be used for analysis of experiments with prototypic core materials.

  18. Prominin-2 expression increases protrusions, decreases caveolae and inhibits Cdc42 dependent fluid phase endocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Raman Deep, E-mail: Takhter.Ramandeep@mayo.edu; Schroeder, Andreas S.; Scheffer, Luana; Holicky, Eileen L.; Wheatley, Christine L.; Marks, David L., E-mail: Marks.david@mayo.edu; Pagano, Richard E.

    2013-05-10

    Highlights: •Prominin-2 expression induced protrusions that co-localized with lipid raft markers. •Prominin-2 expression decreased caveolae, caveolar endocytosis and increased pCav1. •Prominin-2 expression inhibited fluid phase endocytosis by inactivation of Cdc42. •These endocytic effects can be reversed by adding exogenous cholesterol. •Caveolin1 knockdown restored fluid phase endocytosis in Prominin2 expressing cells. -- Abstract: Background: Membrane protrusions play important roles in biological processes such as cell adhesion, wound healing, migration, and sensing of the external environment. Cell protrusions are a subtype of membrane microdomains composed of cholesterol and sphingolipids, and can be disrupted by cholesterol depletion. Prominins are pentaspan membrane proteins that bind cholesterol and localize to plasma membrane (PM) protrusions. Prominin-1 is of great interest as a marker for stem and cancer cells, while Prominin-2 (Prom2) is reportedly restricted to epithelial cells. Aim: To characterize the effects of Prom-2 expression on PM microdomain organization. Methods: Prom2-fluorescent protein was transfected in human skin fibroblasts (HSF) and Chinese hamster ovary (CHO) cells for PM raft and endocytic studies. Caveolae at PM were visualized using transmission electron microscopy. Cdc42 activation was measured and caveolin-1 knockdown was performed using siRNAs. Results: Prom2 expression in HSF and CHO cells caused extensive Prom2-positive protrusions that co-localized with lipid raft markers. Prom2 expression significantly decreased caveolae at the PM, reduced caveolar endocytosis and increased caveolin-1 phosphorylation. Prom2 expression also inhibited Cdc42-dependent fluid phase endocytosis via decreased Cdc42 activation. Effects on endocytosis were reversed by addition of cholesterol. Knockdown of caveolin-1 by siRNA restored Cdc42 dependent fluid phase endocytosis in Prom2-expressing cells. Conclusions: Prom2 protrusions primarily

  19. ESTABLISHED MODES AND STATIC CHARACTERISTICS OF THREE-PHASE ASYNCHRONOUS MOTOR POWERED WITH SINGLE PHASE NETWORK

    Directory of Open Access Journals (Sweden)

    V. S. Malyar

    2016-01-01

    Full Text Available A mathematical model is developed to study the operation of three-phase asynchronous motor with squirrel-cage rotor when the stator winding is powered from a single phase network. To create a rotating magnetic field one of the phases is fed through the capacitor. Due to the asymmetry of power feed not only transients, but the steady-state regimes are dynamic, so they are described by differential equations in any coordinate system. Their study cannot be carried out with sufficient adequacy on the basis of known equivalent circuits and require the use of dynamic parameters. In the mathematical model the state equations of the circuits of the stator and rotor are composed in the stationary three phase coordinate system. Calculation of the established mode is performed by solving the boundary problem that makes it possible to obtain the coordinate dependences over the period, without calculation of the transient process. In order to perform it, the original nonlinear differential equations are algebraized by approximating the variables with the use of cubic splines. The resulting nonlinear system of algebraic equations is a discrete analogue of the initial system of differential equations. It is solved by parameter continuation method. To calculate the static characteristics as a function of a certain variable, the system is analytically differentiated, and then numerically integrated over this variable. In the process of integration, Newton's refinement is performed at each step or at every few steps, making it possible to implement the integration in just a few steps using Euler's method. Jacobi matrices in both cases are the same. To account for the current displacement in the rods of the squirrel-cage rotor, each of them, along with the squirrel-cage rings, is divided in height into several elements. This results in several squirrel-cage rotor windings which are represented by three-phase windings with magnetic coupling between them.

  20. A Well-Posed Two Phase Flow Model and its Numerical Solutions for Reactor Thermal-Fluids Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kadioglu, Samet Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Berry, Ray [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-08-01

    A 7-equation two-phase flow model and its numerical implementation is presented for reactor thermal-fluids applications. The equation system is well-posed and treats both phases as compressible flows. The numerical discretization of the equation system is based on the finite element formalism. The numerical algorithm is implemented in the next generation RELAP-7 code (Idaho National Laboratory (INL)’s thermal-fluids code) built on top of an other INL’s product, the massively parallel multi-implicit multi-physics object oriented code environment (MOOSE). Some preliminary thermal-fluids computations are presented.

  1. A Well-Posed Two Phase Flow Model and its Numerical Solutions for Reactor Thermal-Fluids Analysis

    International Nuclear Information System (INIS)

    Kadioglu, Samet Y.; Berry, Ray; Martineau, Richard

    2016-01-01

    A 7-equation two-phase flow model and its numerical implementation is presented for reactor thermal-fluids applications. The equation system is well-posed and treats both phases as compressible flows. The numerical discretization of the equation system is based on the finite element formalism. The numerical algorithm is implemented in the next generation RELAP-7 code (Idaho National Laboratory (INL)'s thermal-fluids code) built on top of an other INL's product, the massively parallel multi-implicit multi-physics object oriented code environment (MOOSE). Some preliminary thermal-fluids computations are presented.

  2. Numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow

    KAUST Repository

    Zhu, Guangpu

    2018-04-17

    In this paper, we consider the numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow. The nonlinearly coupled model consists of two Cahn-Hilliard type equations and incompressible Navier-Stokes equations. Using the Invariant Energy Quadratization (IEQ) approach, the governing system is transformed into an equivalent form, which allows the nonlinear potentials to be treated efficiently and semi-explicitly. we construct a first and a second-order time marching schemes, which are extremely efficient and easy-to-implement, for the transformed governing system. At each time step, the schemes involve solving a sequence of linear elliptic equations, and computations of phase variables, velocity and pressure are totally decoupled. We further establish a rigorous proof of unconditional energy stability for the semi-implicit schemes. Numerical results in both two and three dimensions are obtained, which demonstrate that the proposed schemes are accurate, efficient and unconditionally energy stable. Using our schemes, we investigate the effect of surfactants on droplet deformation and collision under a shear flow. The increase of surfactant concentration can enhance droplet deformation and inhibit droplet coalescence.

  3. Numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow

    KAUST Repository

    Zhu, Guangpu; Kou, Jisheng; Sun, Shuyu; Yao, Jun; Li, Aifen

    2018-01-01

    In this paper, we consider the numerical approximation of a binary fluid-surfactant phase field model of two-phase incompressible flow. The nonlinearly coupled model consists of two Cahn-Hilliard type equations and incompressible Navier-Stokes equations. Using the Invariant Energy Quadratization (IEQ) approach, the governing system is transformed into an equivalent form, which allows the nonlinear potentials to be treated efficiently and semi-explicitly. we construct a first and a second-order time marching schemes, which are extremely efficient and easy-to-implement, for the transformed governing system. At each time step, the schemes involve solving a sequence of linear elliptic equations, and computations of phase variables, velocity and pressure are totally decoupled. We further establish a rigorous proof of unconditional energy stability for the semi-implicit schemes. Numerical results in both two and three dimensions are obtained, which demonstrate that the proposed schemes are accurate, efficient and unconditionally energy stable. Using our schemes, we investigate the effect of surfactants on droplet deformation and collision under a shear flow. The increase of surfactant concentration can enhance droplet deformation and inhibit droplet coalescence.

  4. Evaluation of an amide-based stationary phase for supercritical fluid chromatography

    Science.gov (United States)

    Borges-Muñoz, Amaris C.; Colón, Luis A.

    2017-01-01

    A relatively new stationary phase containing a polar group embedded in a hydrophobic backbone (i.e., ACE® C18-amide) was evaluated for use in supercritical fluid chromatography. The amide-based column was compared with columns packed with bare silica, C18 silica, and a terminal-amide silica phase. The system was held at supercritical pressure and temperature with a mobile phase composition of CO2 and methanol as cosolvent. The linear solvation energy relationship model was used to evaluate the behavior of these stationary phases, relating the retention factor of selected probes to specific chromatographic interactions. A five-component test mixture, consisting of a group of drug-like molecules was separated isocratically. The results show that the C18-amide stationary phase provided a combination of interactions contributing to the retention of the probe compounds. The hydrophobic interactions are favorable; however, the electron donating ability of the embedded amide group shows a large positive interaction. Under the chromatographic conditions used, the C18-amide column was able to provide baseline resolution of all the drug-like probe compounds in a text mixture, while the other columns tested did not. PMID:27396487

  5. Characterization of Phase Transition in Heisenberg Fluids from Density Functional Theory

    International Nuclear Information System (INIS)

    Li Liangsheng; Li Li; Chen Xiaosong

    2009-01-01

    The phase transition of Heisenberg fluid has been investigated with the density functional theory in mean-field approximation (MF). The matrix of the second derivatives of the grand canonical potential Ω with respect to the particle density fluctuations and the magnetization fluctuations has been investigated and diagonalized. The smallest eigenvalue being 0 signalizes the phase instability and the related eigenvector characterizes this phase transition. We find a Curie line where the order parameter is pure magnetization and a spinodal where the order parameter is a mixture of particle density and magnetization. Along the spinodal, the character of phase instability changes continuously from predominant condensation to predominant ferromagnetic phase transition with the decrease of total density. The spinodal meets the Curie line at the critical endpoint with the reduced density ρ* = ρσ 3 = 0.224 and the reduced temperature T* = kT/ element of = 1.87 (σ is the diameter of Heisenberg hard sphere and element of is the coupling constant).

  6. Unsteady flow of two-phase fluid in circular pipes under applied external magnetic and electrical fields

    International Nuclear Information System (INIS)

    Gedik, Engin; Recebli, Ziyaddin; Kurt, Hueseyin; Kecebas, Ali

    2012-01-01

    The unsteady viscous incompressible and electrically conducting of two-phase fluid flow in circular pipes with external magnetic and electrical field is considered in this present study. Effects of both uniform transverse external magnetic and electrical fields applied perpendicular to the fluid and each other on the two-phase (solid/liquid) unsteady flow is investigated numerically. While iron powders are being used as the first phase of two-phase fluid, pure water was used as the second phase. The system of the derived governing equations, which are based on the Navier-Stokes equations including Maxwell equations, are solved numerically by using Pdex4 function on the Matlab for both phases. The originality of this study is that, in addition to magnetic field, the effect of electrical field on two-phase unsteady fluids is being examined. The magnetic field which is applied on flow decreases the velocity of both phases, whereas the electrical field applied along with magnetic field acted to increase and decrease the velocity values depending on the direction of electrical field. Electrical field alone did not display any impact on two-phase flow. On the other hand, analytical and numerical results are compared and favorable agreements have been obtained. (authors)

  7. CFD simulation of gas and non-Newtonian fluid two-phase flow in anaerobic digesters.

    Science.gov (United States)

    Wu, Binxin

    2010-07-01

    This paper presents an Eulerian multiphase flow model that characterizes gas mixing in anaerobic digesters. In the model development, liquid manure is assumed to be water or a non-Newtonian fluid that is dependent on total solids (TS) concentration. To establish the appropriate models for different TS levels, twelve turbulence models are evaluated by comparing the frictional pressure drops of gas and non-Newtonian fluid two-phase flow in a horizontal pipe obtained from computational fluid dynamics (CFD) with those from a correlation analysis. The commercial CFD software, Fluent12.0, is employed to simulate the multiphase flow in the digesters. The simulation results in a small-sized digester are validated against the experimental data from literature. Comparison of two gas mixing designs in a medium-sized digester demonstrates that mixing intensity is insensitive to the TS in confined gas mixing, whereas there are significant decreases with increases of TS in unconfined gas mixing. Moreover, comparison of three mixing methods indicates that gas mixing is more efficient than mixing by pumped circulation while it is less efficient than mechanical mixing.

  8. Workshop on Two-Phase Fluid Behavior in a Space Environment

    Science.gov (United States)

    Swanson, Theodore D. (Editor); Juhasz, AL (Editor); Long, W. Russ (Editor); Ottenstein, Laura (Editor)

    1989-01-01

    The Workshop was successful in achieving its main objective of identifying a large number of technical issues relating to the design of two-phase systems for space applications. The principal concern expressed was the need for verified analytical tools that will allow an engineer to confidently design a system to a known degree of accuracy. New and improved materials, for such applications as thermal storage and as heat transfer fluids, were also identified as major needs. In addition to these research efforts, a number of specific hardware needs were identified which will require development. These include heat pumps, low weight radiators, advanced heat pipes, stability enhancement devices, high heat flux evaporators, and liquid/vapor separators. Also identified was the need for a centralized source of reliable, up-to-date information on two-phase flow in a space environment.

  9. Rapid purification of diastereoisomers from Piper kadsura using supercritical fluid chromatography with chiral stationary phases.

    Science.gov (United States)

    Xin, Huaxia; Dai, Zhuoshun; Cai, Jianfeng; Ke, Yanxiong; Shi, Hui; Fu, Qing; Jin, Yu; Liang, Xinmiao

    2017-08-04

    Supercritical fluid chromatography (SFC) with chiral stationary phases (CSPs) is an advanced solution for the separation of achiral compounds in Piper kadsura. Analogues and stereoisomers are abundant in natural products, but there are obstacles in separation using conventional method. In this paper, four lignan diastereoisomers, (-)-Galbelgin, (-)-Ganschisandrin, Galgravin and (-)-Veraguensin, from Piper kadsura were separated and purified by chiral SFC. Purification strategy was designed, considering of the compound enrichment, sample purity and purification throughput. Two-step achiral purification method on chiral preparative columns with stacked automated injections was developed. Unconventional mobile phase modifier dichloromethane (DCM) was applied to improve the sample solubility. Four diastereoisomers was prepared at the respective weight of 103.1mg, 10.0mg, 152.3mg and 178.6mg from 710mg extract with the purity of greater than 98%. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Single-phase and two phase bubbly flow in a T connection: theoretical and experimental study

    International Nuclear Information System (INIS)

    Hervieu, Eric

    1988-01-01

    The objective of this research thesis is to highlight the driving factors of the separation of phases of a bubbly flow in a T junction, and to develop a prediction model. In a first part, the author reports the rigorous formulation of equations averaged on the T volume. He shows that it's not possible to solve globally the problem with these equations. Then, he reports a bibliographical study on the modelling of a bubbly flow, and, based upon this study, highlights intrinsic characteristics of the flow, and explains its dynamic mechanisms. He reports the development of the theoretical model, and describes the experimental installation used to validate it. In the third part, he reports the study of the liquid-gas interaction, and presents the adopted approach: study of the behaviour of an isolated bubble within a single-phase flow. Experimentation is used to check theoretical predictions. Results are used to compute phase separation. The obtained results are again compared with experimental results to validate the global relevance of the model [fr

  11. Follicular fluid content and oocyte quality: from single biochemical markers to metabolomics

    Directory of Open Access Journals (Sweden)

    Massobrio Marco

    2009-05-01

    Full Text Available Abstract The assessment of oocyte quality in human in vitro fertilization (IVF is getting increasing attention from embryologists. Oocyte selection and the identification of the best oocytes, in fact, would help to limit embryo overproduction and to improve the results of oocyte cryostorage programs. Follicular fluid (FF is easily available during oocyte pick-up and theorically represents an optimal source on non-invasive biochemical predictors of oocyte quality. Unfortunately, however, the studies aiming to find a good molecular predictor of oocyte quality in FF were not able to identify substances that could be used as reliable markers of oocyte competence to fertilization, embryo development and pregnancy. In the last years, a well definite trend toward passing from the research of single molecular markers to more complex techniques that study all metabolites of FF has been observed. The metabolomic approach is a powerful tool to study biochemical predictors of oocyte quality in FF, but its application in this area is still at the beginning. This review provides an overview of the current knowledge about the biochemical predictors of oocyte quality in FF, describing both the results coming from studies on single biochemical markers and those deriving from the most recent studies of metabolomics

  12. Three-dimensional numerical modeling of turbulent single-phase and two-phase flow in curved pipes

    International Nuclear Information System (INIS)

    Xin, R.C.; Dong, Z.F.; Ebadian, M.A.

    1996-01-01

    In this study, three-dimensional single-phase and two-phase flows in curved pipes have been investigated numerically. Two different pipe configurations were computed. When the results of the single-phase flow simulation were compared with the experimental data, a fairly good agreement was achieved. A flow-developing process has been suggested in single-phase flow, in which the turbulence is stronger near the outer tube wall than near the inner tube wall. For two-phase flow, the Eulerian multiphase model was used to simulate the phase distribution of a three-dimensional gas-liquid bubble flow in curved pipe. The RNG/κ-ε turbulence model was used to determine the turbulence field. An inlet gas void fraction of 5 percent was simulated. The gas phase effects on the liquid phase flow velocity have been examined by comparing the results of single-phase flow and two-phase flow. The findings show that for the downward flow in the U bend, the gas concentrates at the inner portion of the cross section at φ = π/18 - π/6 in most cases. The results of the phase distribution simulation are compared to experimental observations qualitatively and topologically

  13. Single Electron Transistor Platform for Microgravity Proteomics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II program builds from the successful Phase I efforts to demonstrate that Quantum Logic Devices' nanoelectronic platform for biological detection could...

  14. A single-reciprocating-piston two-phase thermofluidic prime-mover

    International Nuclear Information System (INIS)

    Taleb, Aly I.; Timmer, Michael A.G.; El-Shazly, Mohamed Y.; Samoilov, Aleksandr; Kirillov, Valeriy A.; Markides, Christos N.

    2016-01-01

    We explore theoretically a thermodynamic heat-engine concept that has the potential of attaining a high efficiency and power density relative to competing solutions, while having a simple construction with few moving parts and dynamic seals, allowing low capital and operating costs, and long lifetimes. Specifically, an unsteady heat-engine device within which a working fluid undergoes a power cycle featuring phase-change, termed the ‘Evaporative Reciprocating-Piston Engine’ (EPRE) is considered as a potential prime mover for use in combined heat and power (CHP) applications. Based on thermal/fluid-electrical analogies, a theoretical ERPE device is conceptualized initially in the electrical-analogy domain as a linearized, closed-loop active electronic circuit model. The circuit-model representation is designed to potentially exhibit high efficiencies compared to similar, existing two-phase unsteady heat engines. From the simplified circuit model in the electrical domain, and using the thermal/fluid-electrical analogies, one possible configuration of a corresponding physical ERPE device is derived, based on an early prototype of a device currently under development that exhibits some similarities with the ERPE, and used as a physical manifestation of the proposed concept. The corresponding physical ERPE device relies on the alternating phase change of a suitable working-fluid (here, water) to drive a reciprocating displacement of a single vertical piston and to produce sustained oscillations of thermodynamic properties within an enclosed space. Four performance indicators are considered: the operational frequency, the power output, the exergy efficiency, and the heat input/temperature difference imposed externally on the device's heat exchangers that is necessary to sustain oscillations. The effects of liquid inertia, viscous drag, hydrostatic pressure, vapour compressibility and two-phase heat transfer in the various engine components/compartments are

  15. A Multi-Phase Based Fluid-Structure-Microfluidic interaction sensor for Aerodynamic Shear Stress

    Science.gov (United States)

    Hughes, Christopher; Dutta, Diganta; Bashirzadeh, Yashar; Ahmed, Kareem; Qian, Shizhi

    2014-11-01

    A novel innovative microfluidic shear stress sensor is developed for measuring shear stress through multi-phase fluid-structure-microfluidic interaction. The device is composed of a microfluidic cavity filled with an electrolyte liquid. Inside the cavity, two electrodes make electrochemical velocimetry measurements of the induced convection. The cavity is sealed with a flexible superhydrophobic membrane. The membrane will dynamically stretch and flex as a result of direct shear cross-flow interaction with the seal structure, forming instability wave modes and inducing fluid motion within the microfluidic cavity. The shear stress on the membrane is measured by sensing the induced convection generated by membrane deflections. The advantages of the sensor over current MEMS based shear stress sensor technology are: a simplified design with no moving parts, optimum relationship between size and sensitivity, no gaps such as those created by micromachining sensors in MEMS processes. We present the findings of a feasibility study of the proposed sensor including wind-tunnel tests, microPIV measurements, electrochemical velocimetry, and simulation data results. The study investigates the sensor in the supersonic and subsonic flow regimes. Supported by a NASA SBIR phase 1 contract.

  16. Preparation of nanoencapsulated phase change material as latent functionally thermal fluid

    Energy Technology Data Exchange (ETDEWEB)

    Fang Yutang; Kuang Shengyan; Gao Xuenong; Zhang Zhengguo, E-mail: ppytfang@scut.edu.c [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education, South China University of Technology, Guangzhou 510640 (China)

    2009-02-07

    Nanoencapsulated phase change material with polystyrene as the shell and n-octadecane as the core was synthesized using the ultrasonic technique and miniemulsion in situ polymerization. The influences of polymerization factors, including initiator, chain transfer agent (CTA), surfactant, n-octadecane/styrene ratio and hydrophilic co-monomer, on the morphology and thermophysical properties of nanocapsules were systematically investigated. The optimized polymerization conditions were 0.5 wt% of initiator (2,2-azobisisobutyronitrile), 0.4 wt% of CTA (n-dodecyl mercaptan), 2% of composite surfactants which were composed of sodium dodecyl sulfate and poly-(ethylene glycol) monooctylphenyl ether by 1 : 1 in weight ratio, 1 wt% of hydrophilic co-monomer butyl acrylate or 3 wt% of methyl methacrylate and 1 : 1 n-octadecane to styrene in weight ratio. Under these conditions, the z-average size of prepared nanocapsules was 124 nm and the phase change enthalpy was 124.4 kJ kg{sup -1}. The heat capacity was as high as 11.61 kJ kg{sup -1} K{sup -1} at the latex concentration of 20.6 wt%. Thermal stability and viscosity testing show that this fluid had excellent resistance to thermal shock (after 100 cycles, no liquid Oct was observed during heating) and low viscosity (only 3.61 mPa s at the latex concentration of 20.6 wt%), which seems to be promising as a latent functionally thermal fluid.

  17. Single phase flow pressure drop and heat transfer in rectangular metallic microchannels

    International Nuclear Information System (INIS)

    Sahar, Amirah M.; Özdemir, Mehmed R.; Fayyadh, Ekhlas M.; Wissink, Jan; Mahmoud, Mohamed M.; Karayiannis, Tassos G.

    2016-01-01

    Numerical simulations were performed using Fluent 14.5 to investigate single phase flow and conjugate heat transfer in copper rectangular microchannels. Two different configurations were simulated: (1) single channel with hydraulic diameter of 0.561 mm and (2) multichannel configuration consisting of inlet and outlet manifolds and 25 channels with hydraulic diameter of 0.409 mm. In the single channel configuration, four numerical models were investigated namely, 2D thin-wall, 3D thin-wall (heated from the bottom), 3D thin-wall (three side heated) and 3D full conjugate models. In the multichannel configuration, only 3D full conjugate model was used. The simulation results of the single channel configuration were validated using experimental data of water as a test fluid while the results of the multichannel configuration were validated using experimental data of R134a refrigerant. In the multichannel configuration, flow distribution among the channels was also investigated. The 3D thin-wall model simulation was conducted at thermal boundary conditions similar to those assumed in the experimental data reduction (uniform heat flux) and showed excellent agreement with the experimental data. However, the results of the 3D full conjugate model demonstrated that there is a significant conjugate effect and the heat flux is not uniformly distributed along the channel resulting in significant deviation compared to the experimental data (more than 50%). Also, the results demonstrated that there is a significant difference between the 3D thin-wall and full conjugate models. The simulation of the multichannel configuration with an inlet manifold having gradual decrease in cross sectional area achieved very reasonable uniform flow distribution among the channels which will provide uniform heat transfer rates across the base of the microchannels.

  18. Enantioseparation of novel chiral sulfoxides on chlorinated polysaccharide stationary phases in supercritical fluid chromatography.

    Science.gov (United States)

    West, Caroline; Konjaria, Mari-Luiza; Shashviashvili, Natia; Lemasson, Elise; Bonnet, Pascal; Kakava, Rusudan; Volonterio, Alessandro; Chankvetadze, Bezhan

    2017-05-26

    Asymmetric sulfoxides is a particular case of chirality that may be found in natural as well as synthetic products. Twenty-four original molecules containing a sulfur atom as a centre of chirality were analyzed in supercritical fluid chromatography on seven polysaccharide-based chiral stationary phases (CSP) with carbon dioxide - methanol mobile phases. While all the tested CSP provided enantioseparation for a large part of the racemates, chlorinated cellulosic phases proved to be both highly retentive and highly enantioselective towards these species. Favourable structural features were determined by careful comparison of the enantioseparation of the probe molecules. Molecular modelling studies indicate that U-shaped (folded) conformations were most favorable to achieve high enantioresolution on these CSP, while linear (extended) conformations were not so clearly discriminated. For a subset of these species adopting different conformations, a broad range of mobile phase compositions, ranging from 20 to 100% methanol in carbon dioxide, were investigated. While retention decreased continuously in this range, enantioseparation varied in a non-monotonous fashion. Abrupt changes in the tendency curves of retention and selectivity were observed when methanol proportion reaches about 60%, suggesting that a change in the conformation of the analytes and/or chiral selector is occurring at this point. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Heat transfer and velocity characteristics of single- and two-phase flows in a subsonic model gun

    International Nuclear Information System (INIS)

    Bicen, A.F.; Khezzar, L.; Schmidt, M.; Whitelaw, J.H.

    1989-01-01

    Heat transfer and velocity measurements are reported for single- and two-phase flows in the wake of an in-bore projectile propelled by an inert gas at an initial gauge pressure of 8 bars to an exit velocity over 40 m/s in ∼ 33 ms. The results show that with the single phase the turbulent velocity boundary layers occupy over 20% of the barrel radius and that the wall heat transfer increases with distance from the breech and decreases with time during the shot. In the initial chamber, and later in the shot, the heat transfer results are close to those obtained from a convection correlation for a steady turbulent boundary layer, contrary to those at locations swept by the projectile, which are higher by up to 50% throughout the shot. The two-phase flow results show that 55-μm particles with loadings of 1.3% and 4% by volume initially lag the fluid and this lag increases with distance from the breech. Later in the shot the particles catch up and lead the decelerating fluid by an amount that is greater, with the higher particle loading and with a tendency for the particle velocity to increase around the edge of the boundary layer

  20. Consistent scalar and tensor perturbation power spectra in single fluid matter bounce with dark energy era

    Science.gov (United States)

    Bacalhau, Anna Paula; Pinto-Neto, Nelson; Vitenti, Sandro Dias Pinto

    2018-04-01

    perturbations and also for the ratio between tensor and scalar amplitudes, r =T /S ≲0.1 . The amplification of scalar perturbations over tensor perturbations takes place only around the bounce, due to quantum effects, and it would not occur if General Relativity has remained valid throughout this phase. Hence, this is a bouncing model in which a single field induces not only an expanding background dark energy phase but also produces all observed features of cosmological perturbations of quantum mechanical origin at linear order.

  1. Single-step reinitialization and extending algorithms for level-set based multi-phase flow simulations

    Science.gov (United States)

    Fu, Lin; Hu, Xiangyu Y.; Adams, Nikolaus A.

    2017-12-01

    We propose efficient single-step formulations for reinitialization and extending algorithms, which are critical components of level-set based interface-tracking methods. The level-set field is reinitialized with a single-step (non iterative) "forward tracing" algorithm. A minimum set of cells is defined that describes the interface, and reinitialization employs only data from these cells. Fluid states are extrapolated or extended across the interface by a single-step "backward tracing" algorithm. Both algorithms, which are motivated by analogy to ray-tracing, avoid multiple block-boundary data exchanges that are inevitable for iterative reinitialization and extending approaches within a parallel-computing environment. The single-step algorithms are combined with a multi-resolution conservative sharp-interface method and validated by a wide range of benchmark test cases. We demonstrate that the proposed reinitialization method achieves second-order accuracy in conserving the volume of each phase. The interface location is invariant to reapplication of the single-step reinitialization. Generally, we observe smaller absolute errors than for standard iterative reinitialization on the same grid. The computational efficiency is higher than for the standard and typical high-order iterative reinitialization methods. We observe a 2- to 6-times efficiency improvement over the standard method for serial execution. The proposed single-step extending algorithm, which is commonly employed for assigning data to ghost cells with ghost-fluid or conservative interface interaction methods, shows about 10-times efficiency improvement over the standard method while maintaining same accuracy. Despite their simplicity, the proposed algorithms offer an efficient and robust alternative to iterative reinitialization and extending methods for level-set based multi-phase simulations.

  2. Phase II trial of isotonic fluid resuscitation in Kenyan children with severe malnutrition and hypovolaemia

    Directory of Open Access Journals (Sweden)

    Boga Mwanamvua

    2010-10-01

    Full Text Available Abstract Background Children with severe malnutrition who develop shock have a high mortality. Contrary to contemporaneous paediatric practice, current guidelines recommend use of low dose hypotonic fluid resuscitation (half-strength Darrows/5% dextrose (HSD/5D. We evaluated the safety and efficacy of this guideline compared to resuscitation with a standard isotonic solution. Methods A Phase II randomised controlled, safety and efficacy trial in Kenyan children aged over 6 months with severe malnutrition and shock including children with severe dehydration/shock and presumptive septic shock (non-diarrhoeal shock. Eligible children were randomised to HSD/5D or Ringer's Lactate (RL. A maximum of two boluses of 15 ml/kg of HSD/5D were given over two hours (as recommended by guidelines while those randomised to RL received 10 ml/kg aliquots half hourly (maximum 40 ml/kg. Primary endpoint was resolution of shock at 8 and 24 hours. Secondary outcomes included resolution of acidosis, adverse events and mortality. Results 61 children were enrolled: 41 had shock and severe dehydrating diarrhoea, 20 had presumptive septic shock; 69% had decompensated shock. By 8 hours response to volume resuscitation was poor with shock persisting in most children:-HSD/5D 15/22 (68% and RL14/25 (52%, p = 0.39. Oliguria was more prevalent at 8 hours in the HSD/5D group, 9/22 (41%, compared to RL-3/25 (12%, p = 0.02. Mortality was high, HSD/5D-15/26(58% and RL 13/29(45%; p = 0.42. Most deaths occurred within 48 hours of admission. Neither pulmonary oedema nor cardiogenic failure was detected. Conclusions Outcome was universally poor characterised by persistence of shock, oliguria and high case fatality. Isotonic fluid was associated with modest improvement in shock and survival when compared to HSD/5D but inconclusive due to the limitations of design and effectiveness of either resuscitation strategy. Although isotonic fluid resuscitation did not result in cardiogenic heart

  3. Effects of rolling on characteristics of single-phase water flow in narrow rectangular ducts

    International Nuclear Information System (INIS)

    Xing Dianchuan; Yan Changqi; Sun Licheng; Xu Chao

    2012-01-01

    Highlights: ► Mass flow rate and friction pressure drop with different pressure head are compared. ► The effect of pressure head on flow fluctuation is considered theoretically. ► Time-mean and real-time friction pressure drop in different rolling motion are studied. ► Rolling motion influences the fluctuation of friction pressure drop in two aspects. ► New correlation for frictional coefficient in rolling motion is achieved. - Abstract: Experimental and theoretical studies of rolling effects on characteristics of single-phase water flow in narrow rectangular ducts are performed under ambient temperature and pressure. Two types of pressure head are supplied by elevate water tank and pump respectively. The results show that the frictional pressure drop under rolling condition fluctuates periodically, with its amplitude decaying as mean Reynolds number increase and the rolling amplitude decrease, while the amplitude is nearly invariable with rolling period. Rolling motion influences the fluctuation amplitude of frictional pressure drop in two aspects, on the one hand, rolling reduced periodical pulsing flow leads to the fluctuation of the frictional pressure drop, on the other hand, additional force acting on fluid near the wall due to the rolling motion makes local frictional resistance oscillate periodically. The mass flow rate oscillates periodically in rolling motion with the pressure head supplied by water tank, while its fluctuation is so weak that could be neglected for the case of the pressure head supplied by pump. An empirical correlation for the frictional coefficient under rolling condition is achieved, and the experimental data is well correlated. A mathematical model is also developed to study the effect of pressure head on mass flow rate fluctuation in rolling motion. The fluctuation amplitude of the mass flow rate decreases rapidly with a higher pressure head. Comparing with the vertical condition, rolling motion nearly has no effects on

  4. Unravelling the effects of mobile phase additives in supercritical fluid chromatography. Part I: Polarity and acidity of the mobile phase.

    Science.gov (United States)

    West, Caroline; Melin, Jodie; Ansouri, Hassna; Mengue Metogo, Maïly

    2017-04-07

    The mobile phases employed in current supercritical fluid chromatography (SFC) are usually composed of a mixture of pressurized carbon dioxide and a co-solvent. The co-solvent is most often an alcohol and may contain a third component in small proportions, called an additive (acid, base or salt). The polarity of such mobile phase compositions is here re-evaluated with a solvatochromic dye (Nile Red), particularly to assess the contribution of additives. It appears that additives, when employed in usual concentration range (0.1% or 20mM) do not modify the polarity in the immediate environment of the probe. In addition, the combination of carbon dioxide and an alcohol is known to form alkoxylcarbonic acid, supposedly conferring some acidic character to SFC mobile phases. Direct measurements of the apparent pH are impossible, but colour indicators of pH can be used to define the range of apparent pH provided by carbon dioxide-alcohol mixtures, with or without additives. Five colour indicators (Thymol Blue, Bromocresol Green, Methyl Red, Bromocresol Purple, and Bromothymol Blue) were selected to provide a wide range of aqueous pK a values (from 1.7 to 8.9). UV-vis absorption spectra measured in liquid phases of controlled pH were compared to those measured with a diode-array detector employed in SFC, with the help of chemometric methods. Based on these observations, it is concluded that the apparent pH range in carbon dioxide-methanol mobile phases is close to 5. Increasing the proportion of methanol (in the course of a gradient elution for instance) causes decreasing apparent pH. Strong acids can further decrease the apparent pH below 1.7; strong bases have little influence on the apparent pH, probably because, in this range of concentrations, they are titrated by alkoxylcarbonic acid or form ion pairs with alkoxycarbonate. However, bases and salts could stabilize the acidity in the course of gradient runs. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Power coordinated control method with frequency support capability for hybrid single/three-phase microgrid

    DEFF Research Database (Denmark)

    Zhou, Xiaoping; Chen, Yandong; Zhou, Leming

    2018-01-01

    storage unit (ESU) are added into hybrid single/three-phase microgrid, and a power coordinated control method with frequency support capability is proposed for hybrid single/three-phase microgrid in this study. PEU is connected with three single-phase microgrids to coordinate power exchange among three...... phases and provide frequency support for hybrid microgrid. Meanwhile, a power coordinated control method based on the droop control is proposed for PEU to alleviate three-phase power imbalance and reduce voltage fluctuation of hybrid microgrid. Besides, ESU is injected into the DC-link to buffer......Due to the intermittent output power of distributed generations (DGs) and the variability of loads, voltage fluctuation and three-phase power imbalance easily occur when hybrid single/three-phase microgrid operates in islanded mode. To address these issues, the power exchange unit (PEU) and energy...

  6. Staining of fluid-catalytic cracking catalysts: Localising Brønsted acidity within a single catalyst particle

    NARCIS (Netherlands)

    Buurmans, I.L.C.; Ruiz Martinez, J.; van Leeuwen, S.L.; van der Beek, D.; Bergwerff, J.A.; Knowles, W.V.; Vogt, Eelco; Weckhuysen, B.M.

    2012-01-01

    A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components

  7. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

    International Nuclear Information System (INIS)

    Harrison, G.S.; Fountain, M.J.

    1988-01-01

    Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 μg/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

  8. Single phase and two phase erosion corrosion in broilers of gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, G S; Fountain, M J [Operational Engineering Division (Northern Area), Central Electricity Generating Board, Manchester (United Kingdom)

    1988-07-01

    Erosion-corrosion is a phenomenon causing metal wastage in a variety of locations in water and water-steam circuits throughout the power generation industry. Erosion-corrosion can occur in a number of regions of the once-through boiler designs used in the later Magnox and AGR type of gas cooled nuclear reactor. This paper will consider two cases of erosion-corrosion damage (single and two phase) in once through boilers of gas cooled reactors and will describe the solutions that have been developed. The single phase problem is associated with erosion-corrosion damage of mild steel downstream of a boiler inlet flow control orifice. With metal loss rates of up to 1 mm/year at 150 deg. C and pH in the range 9.0-9.4 it was found that 5 {mu}g/kg oxygen was sufficient to reduce erosion-corrosion rates to less than 0.02 mm/year. A combined oxygen-ammonia-hydrazine feedwater regime was developed and validated to eliminate oxygen carryover and hence give protection from stress corrosion in the austenitic section of the AGR once through boiler whilst still providing erosion-corrosion control. Two phase erosion-corrosion tube failures have occurred in the evaporator of the mild steel once through boilers of the later Magnox reactors operating at pressures in the range 35-40 bar. Rig studies have shown that amines dosed in the feedwater can provide a significant reduction in metal loss rates and a tube lifetime assessment technique has been developed to predict potential tube failure profiles in a fully operational boiler. The solutions identified for both problems have been successfully implemented and the experience obtained following implementation including any problems or other benefits arising from the introduction of the new regimes will be presented. Methods for monitoring and evaluating the efficiency of the solutions have been developed and the results from these exercises will also be discussed. Consideration will also be given to the similarities in the metal loss

  9. Single particle Schroedinger fluid and moments of inertia of deformed nuclei

    International Nuclear Information System (INIS)

    Doma, S.B.

    2002-01-01

    The authors have applied the theory of the single-particle Schroedinger fluid to the nuclear collective motion of axially deformed nuclei. A counter example of an arbitrary number of independent nucleons in the anisotropic harmonic oscillator potential at the equilibrium deformation has been also given. Moreover, the ground states of the doubly even nuclei in the s-d shell 20 Ne, 24 Mg, 28 Si, 32 S and 36 Ar are constructed by filling the single-particle states corresponding to the possible values of the number of quanta of excitations n x , n y and n z . Accordingly, the cranking-model, the rigid-body model and the equilibrium-model moments of inertia of these nuclei are calculated as functions of the oscillator parameters ℎω x , ℎω y and ℎω z which are given in terms of the non deformed value ℎω 0 0 , depending on the mass number A, the number of neutrons N, the number of protons Z, and the deformation parameter β. The calculated values of the cranking-model moments of inertia of these nuclei are in good agreement with the corresponding experiential values and show that the considered axially deformed nuclei may have oblate as well as prolate shapes and that the nucleus 24 Mg is the only one which is highly deformed. The rigid-body model and the equilibrium-model moments of inertia of the two nuclei 20 Ne and 24 Mg are also in good agreement with the corresponding experimental values

  10. A Neural Network Approach to Fluid Level Measurement in Dynamic Environments Using a Single Capacitive Sensor

    Directory of Open Access Journals (Sweden)

    Edin TERZIC

    2010-03-01

    Full Text Available A measurement system has been developed using a single tube capacitive sensor to accurately determine the fluid level in vehicular fuel tanks. A novel approach based on artificial neural networks based signal pre-processing and classification has been described in this article. A broad investigation on the Backpropagation neural network and some selected signal pre-processing filters, namely, Moving Mean, Moving Median, and Wavelet Filter has also been presented. An on field drive trial was conducted under normal driving conditions at various fuel volumes ranging from 5 L to 50 L to acquire training samples from the capacitive sensor. A second field trial was conducted to obtain test samples to verify the performance of the neural network. The neural network was trained and verified with 50 % of the training and test samples. The results obtained using the neural network approach having different filtration methods are compared with the results obtained using simple Moving Mean and Moving Median functions. It is demonstrated that the Backpropagation neural network with Moving Median filter produced the most accurate outcome compared with the other signal filtration methods.

  11. Two-dimensional single fluid MHD simulations of plasma opening switches

    International Nuclear Information System (INIS)

    Roderick, N.F.; Payne, S.S.; Peterkin, R.E. Jr.; Frese, M.H.; Hussey, T.W.

    1989-01-01

    Simulations of plasma opening switch have been made using two-dimensional, single fluid, magnetohydrodynamic codes HAM and MACH2. A variety of mechanisms for magnetic field penetration have been investigated. These include plasma convection, classical and microturbulent resistive diffusion, and Hall effect transport. We find that plasma microturbulent models are necessary to explain the broad current channels observed in experiments. Both heuristic and consistent microturbulent models are able to explain observed channel widths and penetration features. The best results are obtained for a consistent model that includes the Buneman, ion acoustic, and lower hybrid microturbulent collision frequencies and threshold conditions. Maximum microturbulent collision frequencies of 5 ω p , are typical. Field transport and current channel profiles are in excellent agreement with experimental observations for GAMBLE I, GAMBLE II, and SUPERMITE experiments. Dominant field penetration mechanisms and center of mass plasma motion are current and density dependent. Including the Hall effect enhanced field penetration. Center of mass motion is negligible for the GAMBLE I experiments but significant for the GAMBLE II conditions. Scaling of plasma opening time with switch length and density can be fit by linear representations for lengths from 0.03 m to 0.24 m and ion densities from 10 18 m -3 to 1.5 times 10 19 m -3 . 15 refs., 7 figs., 1 tab

  12. Liquid-vapour phase behaviour of a polydisperse Lennard-Jones fluid

    International Nuclear Information System (INIS)

    Wilding, Nigel B; Sollich, Peter

    2005-01-01

    We describe a simulation study of the liquid-vapour phase behaviour of a model polydisperse fluid. Particle interactions are given by a Lennard-Jones potential in which polydispersity features both in the particle sizes and the amplitude of their interactions. We address the computational problem of accurately locating the cloud curve for such a system using Monte Carlo simulations within the grand canonical ensemble. The strongly nonlinear variation of the fractional volumes of the phases across the coexistence region precludes naive extrapolation to determine the cloud point density. Instead we propose an improved estimator for the cloud point location and use scaling arguments to predicts its finite-size behaviour. Excellent agreement is found with the simulation results. Application of the method reveals that the measured cloud curve is highly sensitive to the presence of large particles, even when they are extremely rare. This finding is expected to have implications for the reproducibility of experimentally measured phase diagrams in colloids and polymers

  13. Liquid and vapor phase fluids visualization using an exciplex chemical sensor

    International Nuclear Information System (INIS)

    Kim, Jong Uk; Kim, Guang Hoon; Kim, Chang Bum; Suk, Hyyong

    2001-01-01

    Two dimensional slices of the cross-sectional distributions of fuel images in the combustion chamber were visualized quantitatively using a laser-induced exciplex (excited state complex) fluorescence technique. A new exciplex visualization system consisting of 5%DMA (N, N-dimethylaniline) · 5%1, 4,6-TMN (trimethylnaphthalene) in 90% isooctane (2,2,4-trimethylpentane) fuel was employed. In this method, the vapor phase was tagged by the monomer fluorescence while the liquid phase was tracked by the red-shifted exciplex fluorescence with good spectral and spatial resolution. The direct calibration of the fluorescence intensity as a function of the fluorescing dopant concentrations then permitted the determination of quantitative concentration maps of liquid and vapor phases in the fuel. The 308 nm (XeCl) line of the excimer laser was used to excite the doped molecules in the fuel and the resulting fluorescence images were obtained with an ICCD detector as a function time. In this paper, the spectroscopy of the exciplex chemical sensors as well as the optical diagnostic method of the fluid distribution is discussed in detail.

  14. Statistical analysis of entropy generation in longitudinally finned tube heat exchanger with shell side nanofluid by a single phase approach

    Directory of Open Access Journals (Sweden)

    Konchada Pavan Kumar

    2016-06-01

    Full Text Available The presence of nanoparticles in heat exchangers ascertained increment in heat transfer. The present work focuses on heat transfer in a longitudinal finned tube heat exchanger. Experimentation is done on longitudinal finned tube heat exchanger with pure water as working fluid and the outcome is compared numerically using computational fluid dynamics (CFD package based on finite volume method for different flow rates. Further 0.8% volume fraction of aluminum oxide (Al2O3 nanofluid is considered on shell side. The simulated nanofluid analysis has been carried out using single phase approach in CFD by updating the user-defined functions and expressions with thermophysical properties of the selected nanofluid. These results are thereafter compared against the results obtained for pure water as shell side fluid. Entropy generated due to heat transfer and fluid flow is calculated for the nanofluid. Analysis of entropy generation is carried out using the Taguchi technique. Analysis of variance (ANOVA results show that the inlet temperature on shell side has more pronounced effect on entropy generation.

  15. COMMIX-1AR/P: A three-dimensional transient single-phase computer program for thermal hydraulic analysis of single and multicomponent systems. Volume 2, User`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Garner, P.L.; Blomquist, R.N.; Gelbard, E.M.

    1992-09-01

    The COMMIX-1AR/P computer program is designed for analyzing the steady-state and transient aspects of single-phase fluid flow and heat transfer in three spatial dimensions. This version is an extension of the modeling in COMMIX-1A to include multiple fluids in physically separate regions of the computational domain, modeling descriptions for pumps, radiation heat transfer between surfaces of the solids which are embedded in or surround the fluid, a k-{var_epsilon} model for fluid turbulence, and improved numerical techniques. The porous-medium formulation in COMMIX allows the program to be applied to a wide range of problems involving both simple and complex geometrical arrangements. The input preparation and execution procedures are presented for the COMMIX-1AR/P program and several postprocessor programs which produce graphical displays of the calculated results.

  16. Power Based Phase-Locked Loop Under Adverse Conditions with Moving Average Filter for Single-Phase System

    Directory of Open Access Journals (Sweden)

    Menxi Xie

    2017-06-01

    Full Text Available High performance synchronization methord is citical for grid connected power converter. For single-phase system, power based phase-locked loop(pPLL uses a multiplier as phase detector(PD. As single-phase grid voltage is distorted, the phase error information contains ac disturbances oscillating at integer multiples of fundamental frequency which lead to detection error. This paper presents a new scheme based on moving average filter(MAF applied in-loop of pPLL. The signal characteristic of phase error is dissussed in detail. A predictive rule is adopted to compensate the delay induced by MAF, thus achieving fast dynamic response. In the case of frequency deviate from nomimal, estimated frequency is fed back to adjust the filter window length of MAF and buffer size of predictive rule. Simulation and experimental results show that proposed PLL achieves good performance under adverse grid conditions.

  17. Local composition shift of mixed working fluid in gas–liquid flow with phase transition

    International Nuclear Information System (INIS)

    Xu Xiongwen; Liu Jinping; Cao Le; Li Zeyu

    2012-01-01

    Local composition shift is an important characteristic of gas-liquid mixture flow with phase transition. It affects the heat transfer process, stream sonic velocity and the mixture distribution in the thermodynamic cycle. Presently, it is mainly calculated through the empirical models of the void fraction from pure fluid experiments. In this paper, we made efforts to obtain it and its rules basing on conservation equations derivation. The result calculated with propane/i-butane binary mixture was verified by the experiment in the evaporator of a refrigerator. As an extending, it was applied to a ternary mixture with components of methane, propane and butane and more information was presented and analyzed. The calculation approach presented in this paper can be applied any multicomponent mixture, and the rules will be helpful to improve the composition shift theory. - Highlights: ► Local composition shift of mixed working fluid in gas–liquid flow was modelled. ► A solution method for local composition of gas–liquid flow was proposed. ► The solution method was verified by the experimental result. ► Local composition shift mechanism of gas–liquid flow was studied

  18. An Accurate Estimate of the Free Energy and Phase Diagram of All-DNA Bulk Fluids

    Directory of Open Access Journals (Sweden)

    Emanuele Locatelli

    2018-04-01

    Full Text Available We present a numerical study in which large-scale bulk simulations of self-assembled DNA constructs have been carried out with a realistic coarse-grained model. The investigation aims at obtaining a precise, albeit numerically demanding, estimate of the free energy for such systems. We then, in turn, use these accurate results to validate a recently proposed theoretical approach that builds on a liquid-state theory, the Wertheim theory, to compute the phase diagram of all-DNA fluids. This hybrid theoretical/numerical approach, based on the lowest-order virial expansion and on a nearest-neighbor DNA model, can provide, in an undemanding way, a parameter-free thermodynamic description of DNA associating fluids that is in semi-quantitative agreement with experiments. We show that the predictions of the scheme are as accurate as those obtained with more sophisticated methods. We also demonstrate the flexibility of the approach by incorporating non-trivial additional contributions that go beyond the nearest-neighbor model to compute the DNA hybridization free energy.

  19. Fluid simulation of the conduction phase of the plasma erosion opening switch

    International Nuclear Information System (INIS)

    Grossmann, J.M.; Mosher, D.; Ottinger, P.F.

    1987-01-01

    The conduction phase of the plasma erosion openings switch (PEOS) is studied using a 1 1/2-D electromagnetic two-fluid code. The focus of this work is on understanding how two effects, a current-limiting model of electron emission, and the magnetic insulation of electrons at the cathode, determine current conduction in the plasma. Simulations are performed in the parameter regimes of the Gamble I, POP, and PBFA II pulsed power generators, and previous low-density, short-rise time simulations of the PEOS. Fluid code results are compared to a 1-D analytic theory and to the Gamble I and POP experiments. Good agreement between theory and simulation, but mixed agreement between simulation and experiment is found. Experimental Β-field measurements on POP show weaker j x Β compression than the simulation. Current penetration and plasma current channels qualitatively similar to experimental observation are found in the Gamble I regime. However, magnetic insulation of electrons emitted from the cathode bunches the electron flow into narrower current channels than observed experimentally. In several cases, the presence of an electron-scattering or energy-loss mechanism near the cathode must be invoked to overcome magnetic insulation and widen the current channels

  20. Headspace solid-phase microextraction procedures for gas chromatographic analysis of biological fluids and materials.

    Science.gov (United States)

    Mills, G A; Walker, V

    2000-12-01

    Solid-phase microextraction (SPME) is a new solventless sample preparation technique that is finding wide usage. This review provides updated information on headspace SPME with gas chromatographic separation for the extraction and measurement of volatile and semivolatile analytes in biological fluids and materials. Firstly the background to the technique is given in terms of apparatus, fibres used, extraction conditions and derivatisation procedures. Then the different matrices, urine, blood, faeces, breast milk, hair, breath and saliva are considered separately. For each, methods appropriate for the analysis of drugs and metabolites, solvents and chemicals, anaesthetics, pesticides, organometallics and endogenous compounds are reviewed and the main experimental conditions outlined with specific examples. Then finally, the future potential of SPME for the analysis of biological samples in terms of the development of new devices and fibre chemistries and its coupling with high-performance liquid chromatography is discussed.

  1. Thermophysical Properties and Phase Behavior of Fluids for Application in Carbon Capture and Storage Processes.

    Science.gov (United States)

    Trusler, J P Martin

    2017-06-07

    Phase behavior and thermophysical properties of mixtures of carbon dioxide with various other substances are very important for the design and operation of carbon capture and storage (CCS) processes. The available empirical data are reviewed, together with some models for the calculation of these properties. The systems considered in detail are, first, mixtures of carbon dioxide, water, and salts; second, carbon dioxide-rich nonelectrolyte mixtures; and third, mixtures of carbon dioxide with water and amines. The empirical data and the plethora of available models permit the estimation of key fluid properties required in the design and operation of CCS processes. The engineering community would benefit from the further development, and delivery in convenient form, of a small number of these models sufficient to encompass the component slate and operating conditions of CCS processes.

  2. Fractal behavior of single-particle trajectories and isosets in isotropic and anisotropic fluids

    International Nuclear Information System (INIS)

    Kalia, R.K.; Vashishta, P.; de Leeuw, S.W.

    1985-08-01

    Molecular dynamics simulations for a variety of systems in 2 spatial dimensions reveal fractual behavior associated with trajectories and isosets of single particle motion. The fractual dimensions of trajectories and isosets are 2 and 0.5, respectively, irrespective of the nature of the interparticle interaction or thermodynamic state of the system. Recently, we have investigated the fractual behavior of diffusing Ag ions in the superionic phase of Ag 2 S. MD calculations have shown that the Ag ions diffuse anisotropically along certain directions in the lattice of S particles. Fractual dimensions D and anti D for Ag ions are again 2 and 0.5, respectively. These results confirm the universal nature of fractual dimensions of trails and isosets

  3. new topology for single-phase, three-level, spwm vsi with lc filter

    African Journals Online (AJOL)

    level PWM inverter. However, this is not the case with single-phase PWM inverters. In these days, the popular single-phase inverters adopt the full-bridge type using approximate sinusoidal modulation technique. The output voltage in them has two values: zero and pos- itive supply dc voltage levels in the positive half cycle.

  4. Torque Analysis With Saturation Effects for Non-Salient Single-Phase Permanent-Magnet Machines

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Ritchie, Ewen

    2011-01-01

    The effects of saturation on torque production for non-salient, single-phase, permanent-magnet machines are studied in this paper. An analytical torque equation is proposed to predict the instantaneous torque with saturation effects. Compared to the existing methods, it is computationally faster......-element results, and experimental results obtained on a prototype single-phase permanent-magnet machine....

  5. Large conditional single-photon cross-phase modulation

    Science.gov (United States)

    Hosseini, Mahdi; Duan, Yiheng; Vuletić, Vladan

    2016-01-01

    Deterministic optical quantum logic requires a nonlinear quantum process that alters the phase of a quantum optical state by π through interaction with only one photon. Here, we demonstrate a large conditional cross-phase modulation between a signal field, stored inside an atomic quantum memory, and a control photon that traverses a high-finesse optical cavity containing the atomic memory. This approach avoids fundamental limitations associated with multimode effects for traveling optical photons. We measure a conditional cross-phase shift of π/6 (and up to π/3 by postselection on photons that remain in the system longer than average) between the retrieved signal and control photons, and confirm deterministic entanglement between the signal and control modes by extracting a positive concurrence. By upgrading to a state-of-the-art cavity, our system can reach a coherent phase shift of π at low loss, enabling deterministic and universal photonic quantum logic. PMID:27519798

  6. the steady-state performance characteristics of single phase transfer

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... field (SPTF) machine operating in the asynchronous mode from which the performance charac- teristics could be ... motor from a poly-phase induction motor by discon- necting one of its .... tating magnetic field. The pulsating ...

  7. Modeling and analysis of hydrodynamic instabilities in two-phase flow using two-fluid model

    International Nuclear Information System (INIS)

    Zhou, J.; Podowski, M.Z.

    2001-01-01

    Because of the practical importance of two-phase flow instabilities, especially in boiling water nuclear reactor technology, substantial efforts have been made to date to understand the physical phenomena governing such instabilities and to develop computational tools to model the dynamics of marginally-stable/unstable boiling systems. The purpose of this paper is to present an integrated methodology for the analysis of flow-induced instabilities in boiling channels and systems. The major novel aspects of the proposed approach are: (a) it is based on the combined frequency-domain and time-domain methods, the former used to quantify stability margins and to determine the onset of instability conditions, the latter to study the nonlinear system response outside the stability boundaries identified using the nearly-exact results of the frequency-domain analysis; (b) the two-fluid model of two-phase flow has been used for the first time to analytically derive the boiling channel transfer functions for the parallel-channel and channel-to-channel instability modes. In this way, the major characteristics of a boiling system, including the onset-of-instability conditions, can be readily evaluated by using the qualitative frequency-domain approach, whereas the explicit time-domain integration is performed, if necessary, only for the operating conditions that have already been identified as unstable. Both methods use the same physical two-fluid model that, in one case, is linearized and used to derive a rigorous analytical solution in the complex domain, and, in the other case, is solved numerically using an algorithm developed especially for this purpose. The results using both methods have been compared against each other and extensively tested. The testing and validation of the new model included comparisons of the predicted steady-state distributions of major parameters and of the transient channel response against experimental data

  8. Evaluation of two-phase flow solvers using Level Set and Volume of Fluid methods

    Science.gov (United States)

    Bilger, C.; Aboukhedr, M.; Vogiatzaki, K.; Cant, R. S.

    2017-09-01

    Two principal methods have been used to simulate the evolution of two-phase immiscible flows of liquid and gas separated by an interface. These are the Level-Set (LS) method and the Volume of Fluid (VoF) method. Both methods attempt to represent the very sharp interface between the phases and to deal with the large jumps in physical properties associated with it. Both methods have their own strengths and weaknesses. For example, the VoF method is known to be prone to excessive numerical diffusion, while the basic LS method has some difficulty in conserving mass. Major progress has been made in remedying these deficiencies, and both methods have now reached a high level of physical accuracy. Nevertheless, there remains an issue, in that each of these methods has been developed by different research groups, using different codes and most importantly the implementations have been fine tuned to tackle different applications. Thus, it remains unclear what are the remaining advantages and drawbacks of each method relative to the other, and what might be the optimal way to unify them. In this paper, we address this gap by performing a direct comparison of two current state-of-the-art variations of these methods (LS: RCLSFoam and VoF: interPore) and implemented in the same code (OpenFoam). We subject both methods to a pair of benchmark test cases while using the same numerical meshes to examine a) the accuracy of curvature representation, b) the effect of tuning parameters, c) the ability to minimise spurious velocities and d) the ability to tackle fluids with very different densities. For each method, one of the test cases is chosen to be fairly benign while the other test case is expected to present a greater challenge. The results indicate that both methods can be made to work well on both test cases, while displaying different sensitivity to the relevant parameters.

  9. Analysis of two-phase flow inter-subchannel mass and momentum exchanges by the two-fluid model approach

    Energy Technology Data Exchange (ETDEWEB)

    Ninokata, H. [Tokyo Institute of Technology (Japan); Deguchi, A. [ENO Mathematical Analysis, Tokyo (Japan); Kawahara, A. [Kumamoto Univ., Kumamoto (Japan)

    1995-09-01

    A new void drift model for the subchannel analysis method is presented for the thermohydraulics calculation of two-phase flows in rod bundles where the flow model uses a two-fluid formulation for the conservation of mass, momentum and energy. A void drift model is constructed based on the experimental data obtained in a geometrically simple inter-connected two circular channel test sections using air-water as working fluids. The void drift force is assumed to be an origin of void drift velocity components of the two-phase cross-flow in a gap area between two adjacent rods and to overcome the momentum exchanges at the phase interface and wall-fluid interface. This void drift force is implemented in the cross flow momentum equations. Computational results have been successfully compared to experimental data available including 3x3 rod bundle data.

  10. Influence of the pore fluid on the phase velocity in bovine trabecular bone In Vitro: Prediction of the biot model

    Science.gov (United States)

    Lee, Kang Il

    2013-01-01

    The present study aims to investigate the influence of the pore fluid on the phase velocity in bovine trabecular bone in vitro. The frequency-dependent phase velocity was measured in 20 marrow-filled and water-filled bovine femoral trabecular bone samples. The mean phase velocities at frequencies between 0.6 and 1.2 MHz exhibited significant negative dispersions for both the marrow-filled and the water-filled samples. The magnitudes of the dispersions showed no significant differences between the marrow-filled and the water-filled samples. In contrast, replacement of marrow by water led to a mean increase in the phase velocity of 27 m/s at frequencies from 0.6 to 1.2 MHz. The theoretical phase velocities of the fast wave predicted by using the Biot model for elastic wave propagation in fluid-saturated porous media showed good agreements with the measurements.

  11. Computational fluid dynamics modeling of two-phase flow in a BWR fuel assembly

    International Nuclear Information System (INIS)

    Andrey Ioilev; Maskhud Samigulin; Vasily Ustinenko; Simon Lo; Adrian Tentner

    2005-01-01

    Full text of publication follows: The goal of this project is to develop an advanced Computational Fluid Dynamics (CFD) computer code (CFD-BWR) that allows the detailed analysis of the two-phase flow and heat transfer phenomena in a Boiling Water Reactor (BWR) fuel bundle under various operating conditions. This code will include more fundamental physical models than the current generation of sub-channel codes and advanced numerical algorithms for improved computational accuracy, robustness, and speed. It is highly desirable to understand the detailed two-phase flow phenomena inside a BWR fuel bundle. These phenomena include coolant phase changes and multiple flow regimes which directly influence the coolant interaction with fuel assembly and, ultimately, the reactor performance. Traditionally, the best analysis tools for the analysis of two-phase flow phenomena inside the BWR fuel assembly have been the sub-channel codes. However, the resolution of these codes is still too coarse for analyzing the detailed intra-assembly flow patterns, such as flow around a spacer element. Recent progress in Computational Fluid Dynamics (CFD), coupled with the rapidly increasing computational power of massively parallel computers, shows promising potential for the fine-mesh, detailed simulation of fuel assembly two-phase flow phenomena. However, the phenomenological models available in the commercial CFD programs are not as advanced as those currently being used in the sub-channel codes used in the nuclear industry. In particular, there are no models currently available which are able to reliably predict the nature of the flow regimes, and use the appropriate sub-models for those flow regimes. The CFD-BWR code is being developed as a customized module built on the foundation of the commercial CFD Code STAR-CD which provides general two-phase flow modeling capabilities. The paper describes the model development strategy which has been adopted by the development team for the

  12. A Two-Phase Flow Solver for Incompressible Viscous Fluids, Using a Pure Streamfunction Formulation and the Volume of Fluid Technique

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    Accurate multi-phase flow solvers at low Reynolds number are of particular interest for the simulation of interface instabilities in the co-processing of multilayered material. We present a two-phase flow solver for incompressible viscous fluids which uses the streamfunction as the primary variable...... of the flow. Contrary to fractional step methods, the streamfunction formulation eliminates the pressure unknowns, and automatically fulfills the incompressibility constraint by construction. As a result, the method circumvents the loss of temporal accuracy at low Reynolds numbers. The interface is tracked...

  13. A Two-Phase Flow Solver for Incompressible Viscous Fluids, Using a Pure Streamfunction Formulation and the Volume of Fluid Technique

    DEFF Research Database (Denmark)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    2014-01-01

    Accurate multi-phase flow solvers at low Reynolds number are of particular interest for the simulation of interface instabilities in the co-processing of multilayered material. We present a two-phase flow solver for incompressible viscous fluids which uses the streamfunction as the primary variable...... of the flow. Contrary to fractional step methods, the streamfunction formulation eliminates the pressure unknowns, and automatically fulfills the incompressibility constraint by construction. As a result, the method circumvents the loss of temporal accuracy at low Reynolds numbers. The interface is tracked...

  14. 1.26 Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  15. 1.26 Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal is for the development of an innovative compact, high power, and extremely reliable 1.26 micron Ho-doped single frequency fiber laser. The proposed...

  16. Single Molecule Scanning of DNA Radiation Oxidative Damage, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal will develop an assay to map genomic DNA, at the single molecule level and in a nanodevice, for oxidative DNA damage arising from radiation exposure;...

  17. Design of a Subscale Propellant Slag Evaluation Motor Using Two-Phase Fluid Dynamic Analysis

    Science.gov (United States)

    Whitesides, R. Harold; Dill, Richard A.; Purinton, David C.; Sambamurthi, Jay K.

    1996-01-01

    Small pressure perturbations in the Space Shuttle Reusable Solid Rocket Motor (RSRM) are caused by the periodic expulsion of molten aluminum oxide slag from a pool that collects in the aft end of the motor around the submerged nozzle nose during the last half of motor operation. It is suspected that some motors produce more slag than others due to differences in aluminum oxide agglomerate particle sizes that may relate to subtle differences in propellant ingredient characteristics such as particle size distributions or processing variations. A subscale motor experiment was designed to determine the effect of propellant ingredient characteristics on the propensity for slag production. An existing 5 inch ballistic test motor was selected as the basic test vehicle. The standard converging/diverging nozzle was replaced with a submerged nose nozzle design to provide a positive trap for the slag that would increase the measured slag weights. Two-phase fluid dynamic analyses were performed to develop a nozzle nose design that maintained similitude in major flow field features with the full scale RSRM. The 5 inch motor was spun about its longitudinal axis to further enhance slag collection and retention. Two-phase flow analysis was used to select an appropriate spin rate along with other considerations, such as avoiding bum rate increases due to radial acceleration effects. Aluminum oxide particle distributions used in the flow analyses were measured in a quench bomb for RSRM type propellants with minor variations in ingredient characteristics. Detailed predictions for slag accumulation weights during motor bum compared favorably with slag weight data taken from defined zones in the subscale motor and nozzle. The use of two-phase flow analysis proved successful in gauging the viability of the experimental program during the planning phase and in guiding the design of the critical submerged nose nozzle.

  18. Experimental study on the convective heat transfer enhancement in single-phase steam flow by a support grid

    International Nuclear Information System (INIS)

    Kim, Byoung Jae; Kim, Kihwan; Kim, Dong-Eok; Youn, Young-Jung; Park, Jong-Kuk; Moon, Sang-Ki; Song, Chul-Hwa

    2014-01-01

    Highlights: • The convective heat transfer enhancement by support grids is investigated. • Experiments were performed in a square array 2 × 2 rod bundle. • The enhancement was affected not only by the blockage ratio also by the Reynolds number. • For low Reynolds numbers, the enhancement depends on the Reynolds number (Re). • For high Reynolds numbers, the enhancement is nearly independent of Re. - Abstract: Single-phase flow occurs in the fuel rod bundle of a pressurized water reactor, during the normal operation period or at the early stage of the reflood phase in a loss-of-coolant accident scenario. In the former period, the flow is single-phase water flow, but in the latter case, the flow is single-phase steam flow. Support grids are required to maintain a proper geometry configuration of fuel rods within nuclear fuel assemblies. This study was conducted to elucidate the effects of support grids on the convective heat transfer in single-phase steam flow. Experiments were made in a square array 2 × 2 rod bundle. The four electrically-heating rods were maintained by support grids with mixing vanes creating a swirl flow. Two types of support grids were considered in this study. The two types are geometrically similar except the blockage ratio by different mixing vane angles. For all test runs, 2 kW power was supplied to each rod. The working fluid was superheated steam with Re = 2,301–39,594. The axial profile of the rod surface temperatures was measured, and the convective heat transfer enhancement by the presence of the support grids was examined. The peak heat transfer enhancement was a function of not only the blockage ratio but also the Reynolds number. Given the same blockage ratio, the heat transfer enhancement was sensitive to the Reynolds number in laminar flow, whereas it was nearly independent of the Reynolds number in turbulent flow

  19. 16 channel WDM regeneration in a single phase-sensitive amplifier through optical Fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Da Ros, Francesco; Lillieholm, Mads

    2016-01-01

    We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude...

  20. Analysis and MPPT control of a wind-driven three-phase induction generator feeding single-phase utility grid

    Directory of Open Access Journals (Sweden)

    Krishnan Arthishri

    2017-05-01

    Full Text Available In this study, a three-phase diode bridge rectifier and a single-phase voltage source inverter topology has been proposed for feeding single-phase utility grid employing a three-phase induction generator fed from wind energy. A self-excited induction generator configuration has been chosen for wide speed operation of wind turbine system, which gives the scope for extracting maximum power available in the wind. In addition to maximum power point tracking (MPPT, the generator can be loaded to its rated capacity for feeding single-phase utility grid using a three-phase induction machine, whereas it is not possible with existing configurations because of the absence of power converters. For the proposed system, MPPT algorithm has been devised by continuously monitoring the grid current and a proportional resonant controller has been employed for grid synchronisation of voltage source inverter with single-phase grid. A MATLAB/Simulink model of the proposed system has been developed to ascertain its successful working by predetermining the overall performance characteristics. The present proposal has also been tested with sag, swell and distortion in the grid voltage. The control strategy has been implemented using field programmable gate array (FPGA controller with modularised programming approach. The efficacy of the system has been demonstrated with the results obtained from an experimental set-up in the laboratory.

  1. Circadian phase resetting via single and multiple control targets.

    Directory of Open Access Journals (Sweden)

    Neda Bagheri

    2008-07-01

    Full Text Available Circadian entrainment is necessary for rhythmic physiological functions to be appropriately timed over the 24-hour day. Disruption of circadian rhythms has been associated with sleep and neuro-behavioral impairments as well as cancer. To date, light is widely accepted to be the most powerful circadian synchronizer, motivating its use as a key control input for phase resetting. Through sensitivity analysis, we identify additional control targets whose individual and simultaneous manipulation (via a model predictive control algorithm out-perform the open-loop light-based phase recovery dynamics by nearly 3-fold. We further demonstrate the robustness of phase resetting by synchronizing short- and long-period mutant phenotypes to the 24-hour environment; the control algorithm is robust in the presence of model mismatch. These studies prove the efficacy and immediate application of model predictive control in experimental studies and medicine. In particular, maintaining proper circadian regulation may significantly decrease the chance of acquiring chronic illness.

  2. A single-phase model for liquid-feed DMFCs with non-Tafel kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Vera, Marcos [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Avda. de la Universidad 30, 28911 Leganes (Spain)

    2007-09-27

    An isothermal single-phase 3D/1D model for liquid-feed direct methanol fuel cells (DMFC) is presented. Three-dimensional (3D) mass, momentum and species transport in the anode channels and gas diffusion layer is modeled using a commercial, finite-volume based, computational fluid dynamics (CFD) software complemented with user supplied subroutines. The 3D model is locally coupled to a one-dimensional (1D) model accounting for the electrochemical reactions in both the anode and the cathode, which provides a physically sound boundary condition for the velocity and methanol concentration fields at the anode gas diffusion layer/catalyst interface. The 1D model - comprising the membrane-electrode assembly, cathode gas diffusion layer, and cathode channel - assumes non-Tafel kinetics to describe the complex kinetics of the multi-step methanol oxidation reaction at the anode, and accounts for the mixed potential associated with methanol crossover, induced both by diffusion and electro-osmotic drag. Polarization curves computed for various methanol feed concentrations, temperatures, and methanol feed velocities show good agreement with recent experimental results. The spatial distribution of methanol in the anode channels, together with the distributions of current density, methanol crossover and fuel utilization at the anode catalyst layer, are also presented for different opperating conditions. (author)

  3. Effects of solid/liquid phase fractionation on pH and aqueous species molality in subduction zone fluids

    Science.gov (United States)

    Zhong, X.; Galvez, M. E.

    2017-12-01

    Metamorphic fluids are a crucial ingredient of geodynamic evolution, i.e. heat transfer, rock mechanics and metamorphic/metasomatic reactions. During crustal evolution at elevated P and T, rock forming components can be effectively fractionated from the reactive rock system by at least two processes: 1. extraction from porous rocks by liquid phases such as solute-bearing (e.g. Na+, Mg2+) aqueous fluids or partial melts. 2. isolation from effective bulk rock composition due to slow intragranular diffusion in high-P refractory phases such as garnet. The effect of phase fractionation (garnet, partial melt and aqueous species) on fluid - rock composition and properties remain unclear, mainly due to a high demand in quantitative computations of the thermodynamic interactions between rocks and fluids over a wide P-T range. To investigate this problem, we build our work on an approach initially introduced by Galvez et al., (2015) with new functionalities added in a MATLAB code (Rubisco). The fluxes of fractionated components in fluid, melt and garnet are monitored along a typical prograde P-T path for a model crustal pelite. Some preliminary results suggest a marginal effect of fractionated aqueous species on fluid and rock properties (e.g. pH, composition), but the corresponding fluxes are significant in the context of mantle wedge metasomatism. Our work provides insight into the role of high-P phase fractionation on mass redistribution between the surface and deep Earth in subduction zones. Existing limitations relevant to our liquid/mineral speciation/fractionation model will be discussed as well. ReferencesGalvez, M.E., Manning, C.E., Connolly, J.A.D., Rumble, D., 2015. The solubility of rocks in metamorphic fluids: A model for rock-dominated conditions to upper mantle pressure and temperature. Earth Planet. Sci. Lett. 430, 486-498.

  4. Some numerical methods for two-fluid two-phase flows in oil pipes; Quelques methodes numeriques pour les ecoulements diphasiques bi-fluide en conduites petrolieres

    Energy Technology Data Exchange (ETDEWEB)

    Masella, J.M.

    1997-05-29

    This thesis is devoted to the numerical simulation of some two-fluid models describing gas-liquid two-phase flow in pipes. The numerical models developed here can be more generally used in the modelling of a wide class of physical models which can be put under an hyperbolic form. We introduce first two isothermal two-fluid models, composed of a mass balance equation and a momentum equation written in each phase, describing respectively a stratified two-phase flow and a dispersed two-phase flow. These models are hyperbolic under some physical assumptions and can be written under a nonconservative vectorial system. We define and analyse a new numerical finite volume scheme (v{integral}Roe) founded on a linearized Riemann solver. This scheme does not need any analytical calculation and gives good results in the tracking of shocks. We compare this new scheme with the classical Roe scheme. Then we propose and study some numerical models, with and without flux splitting method, which are adapted to the discretization of the two-fluid models. This numerical models are given by a finite volume integration of the equations, and lean on the v{integral} scheme. In order to reducing cpu time, due to the low Mach number of two-phase flows, acoustic waves are implicit. Afterwards we proposed a discretization of boundary conditions, which allows the generation of transient flows in pipe. Some numerical academic and more physical tests show the good behaviour of the numerical methods. (author) 77 refs.

  5. Theoretical modelling and experimental investigation of single-phase and two-phase flow division at a tee-junction

    International Nuclear Information System (INIS)

    Lemonnier, H.; Hervieu, E.

    1991-01-01

    Phase separation in a tee-junction is modelled in the particular case of bubbly-flow. The model is based on a two-dimensional approach and hence, uses local equations. The first step consists in modelling the single-phase flow in the tee-junction. The free streamline theory is used to predict the flow of the continuous phase. The two recirculation zones which are presented in this case are predicted by the model. The second step consists in predicting the gas bubble paths as a result of the actions of the single-phase flow. Finally, the trajectories of gas bubbles are used to predict the separation characteristics of the tee-junction. Each step of the modelling procedure has been carefully tested by an in-depth experimental investigation. Excellent quantitative agreement is obtained between experimental results and model predictions. Moreover, the phase separation phenomenon is found to be clearly described by the model. (orig.)

  6. Implicit approximate Riemann solver for two fluid two phase flow models

    International Nuclear Information System (INIS)

    Raymond, P.; Toumi, I.; Kumbaro, A.

    1993-01-01

    This paper is devoted to the description of new numerical methods developed for the numerical treatment of two phase flow models with two velocity fields which are now widely used in nuclear engineering for design or safety calculations. These methods are finite volumes numerical methods and are based on the use of Approximate Riemann Solver's concepts in order to define convective flux versus mean cell quantities. The first part of the communication will describe the numerical method for a three dimensional drift flux model and the extensions which were performed to make the numerical scheme implicit and to have fast running calculations of steady states. Such a scheme is now implemented in the FLICA-4 computer code devoted to 3-D steady state and transient core computations. We will present results obtained for a steady state flow with rod bow effect evaluation and for a Steam Line Break calculation were the 3-D core thermal computation was coupled with a 3-D kinetic calculation and a thermal-hydraulic transient calculation for the four loops of a Pressurized Water Reactor. The second part of the paper will detail the development of an equivalent numerical method based on an approximate Riemann Solver for a two fluid model with two momentum balance equations for the liquid and the gas phases. The main difficulty for these models is due to the existence of differential modelling terms such as added mass effects or interfacial pressure terms which make hyperbolic the model. These terms does not permit to write the balance equations system in a conservative form, and the classical theory for discontinuity propagation for non-linear systems cannot be applied. Meanwhile, the use of non-conservative products theory allows the study of discontinuity propagation for a non conservative model and this will permit the construction of a numerical scheme for two fluid two phase flow model. These different points will be detailed in that section which will be illustrated by

  7. Self-Assembling, Stable Photonic Bend-Gap Phases in Emulsions of Chiral Nematics with Isotropic Fluids

    Science.gov (United States)

    Huang, Chien-Yueh; Petschek, R. G.

    1998-03-01

    We investigate the possible mesophases in emulsions of chiral nematic liquid crystals with immiscible isotropic fluids and surfactants. The interactions between the orientational fields of the chiral nematics and the surfactant membranes together with the topological constraints affect stability of micellar geometries and produce a new phase diagram. We compare the free energies of various candidate phases. Appropriate, likely realizable conditions on the surfactant and the pitch of the liquid crystal result in thermodynamically stable blue-phase like phases for a relatively wide range of parameters. Processing such emulsions may result in materials with photonic band gaps.

  8. Single-Phase Bundle Flows Including Macroscopic Turbulence Model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Jun; Yoon, Han Young [KAERI, Daejeon (Korea, Republic of); Yoon, Seok Jong; Cho, Hyoung Kyu [Seoul National University, Seoul (Korea, Republic of)

    2016-05-15

    To deal with various thermal hydraulic phenomena due to rapid change of fluid properties when an accident happens, securing mechanistic approaches as much as possible may reduce the uncertainty arising from improper applications of the experimental models. In this study, the turbulence mixing model, which is well defined in the subchannel analysis code such as VIPRE, COBRA, and MATRA by experiments, is replaced by a macroscopic k-e turbulence model, which represents the aspect of mathematical derivation. The performance of CUPID with macroscopic turbulence model is validated against several bundle experiments: CNEN 4x4 and PNL 7x7 rod bundle tests. In this study, the macroscopic k-e model has been validated for the application to subchannel analysis. It has been implemented in the CUPID code and validated against CNEN 4x4 and PNL 7x7 rod bundle tests. The results showed that the macroscopic k-e turbulence model can estimate the experiments properly.

  9. Ultrafast photoinduced structure phase transition in antimony single crystals

    NARCIS (Netherlands)

    Fausti, Daniele; Misochko, Oleg V.; van Loosdrecht, Paul H. M.

    2009-01-01

    Picosecond Raman scattering is used to study the photoinduced ultrafast dynamics in Peierls distorted antimony. We find evidence for an ultrafast nonthermal reversible structural phase transition. Most surprisingly, we find evidence that this transition evolves toward a lower symmetry in contrast to

  10. Method of manufacture of single phase ceramic superconductors

    Science.gov (United States)

    Singh, Jitrenda P.; Poeppel, Roger B.; Goretta, Kenneth C.; Chen, Nan

    1995-01-01

    A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa.sub.2 Cu.sub.3 O.sub.x indicates that sintering kinetics are enhanced at reduced p(O.sub.2) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910.degree. C. increased from 79 to 94% theoretical when p(O.sub.2) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O.sub.2) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910.degree. C resulted in a fine-grain microstructure, with an average grain size of about 4 .mu.m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth. The method of pinning grain boundaries by small scale decompositive products and then annealing to convert its product to the desired phase can be used for other complex asides. Such a microstructure results in reduced microcracking, strengths as high as 230 MPa and high critical current density capacity.

  11. Photon Cascade from a Single Crystal Phase Nanowire Quantum Dot

    DEFF Research Database (Denmark)

    Bouwes Bavinck, Maaike; Jöns, Klaus D; Zieliński, Michal

    2016-01-01

    . We notice that the emission spectra consist often of two peaks close in energy, which we explain with a comprehensive theory showing that the symmetry of the system plays a crucial role for the hole levels forming hybridized orbitals. Our results state that crystal phase quantum dots have promising...

  12. Three-dimensional fluid mechanics of particulate two-phase flows in U-bend and helical conduits

    Science.gov (United States)

    Tiwari, Prashant; Antal, Steven P.; Podowski, Michael Z.

    2006-04-01

    The results of numerous studies performed to date have shown that the performance of various hydraulic systems can be significantly improved by using curved conduit geometries instead of straight tubes. In particular, the formation of Dean vortices, which enhance the development of centrifugal instabilities, has been identified as a factor behind reducing the near-wall concentration buildup in particulate flow devices (e.g., in membrane filtration modules). Still, several issues regarding the effect of conduit curvature on local multidimensional phenomena governing fluid flow still remain open. A related issue is concerned with the impact that conduit geometry makes on the concentration distribution of a dispersed phase in two-phase flows in general, and in particulate flows (solid/liquid or solid/gas suspensions) in particular. It turns out that only very limited efforts have been made in the past to understand the fluid mechanics of such flows via advanced computer simulations. The purpose of this paper is to present the results of full three-dimensional (3D) theoretical and numerical analyses of single- and two-phase dilute particle/liquid flows in U-bend and helical curved conduits. The numerical analysis is based on computational fluid dynamics (CFD) simulations performed using a state-of-the-art multiphase flow computer code, NPHASE. The major issues discussed in the first part of the paper are concerned with the effect of curved/coiled geometry on the evolution of flow field and the associated wall shear. It has been demonstrated that the primary curvature (a common factor for both the U-bend and helix geometries) may cause a substantial asymmetry in the radial distribution of the main flow velocity. This, in turn, leads to a significant, albeit highly nonuniform, increase in the wall shear stress. Specifically, the wall shear around the outer half of tube circumference may become twice the corresponding value for a straight tube, and gradually decrease to

  13. Fluid-structure coupling effects on periodically transient flow of a single-blade sewage centrifugal pump

    International Nuclear Information System (INIS)

    Pei, Ji; Yuan, Shouqi; Yuan, Jianping

    2013-01-01

    A partitioned fluid-structure interaction (FSI) solving strategy that depends on problem characteristics is applied to quantitatively obtain the coupling effects of a fluid-structure system in a single-blade centrifugal pump on the unsteady flow. A two-way coupling method is employed to realize strong FSI effects in the calculation procedure. The successful impeller oscillation measurement using two proximity sensors validated the FSI simulation accuracy in a complicated and practical fluid-structure system having a rotating component. The results show that the hydrodynamic force deviation can be observed in the results for the coupled versus uncoupled cases. Additionally, the coupled unsteady pressure is larger than the uncoupled value for every monitoring point at every impeller rotation position. Comparison results for different monitoring points under an overload condition and partial-load condition display the same regularities. To some extent, this interaction mechanism would affect the accuracy and reliability of the unsteady flow and rotor deflection analysis.

  14. ECO2M: A TOUGH2 Fluid Property Module for Mixtures of Water, NaCl, and CO2, Including Super- and Sub-Critical Conditions, and Phase Change Between Liquid and Gaseous CO2

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, K.

    2011-04-01

    ECO2M is a fluid property module for the TOUGH2 simulator (Version 2.0) that was designed for applications to geologic storage of CO{sub 2} in saline aquifers. It includes a comprehensive description of the thermodynamics and thermophysical properties of H{sub 2}O - NaCl - CO{sub 2} mixtures, that reproduces fluid properties largely within experimental error for temperature, pressure and salinity conditions in the range of 10 C {le} T {le} 110 C, P {le} 600 bar, and salinity from zero up to full halite saturation. The fluid property correlations used in ECO2M are identical to the earlier ECO2N fluid property package, but whereas ECO2N could represent only a single CO{sub 2}-rich phase, ECO2M can describe all possible phase conditions for brine-CO{sub 2} mixtures, including transitions between super- and sub-critical conditions, and phase change between liquid and gaseous CO{sub 2}. This allows for seamless modeling of CO{sub 2} storage and leakage. Flow processes can be modeled isothermally or non-isothermally, and phase conditions represented may include a single (aqueous or CO{sub 2}-rich) phase, as well as two-and three-phase mixtures of aqueous, liquid CO{sub 2} and gaseous CO{sub 2} phases. Fluid phases may appear or disappear in the course of a simulation, and solid salt may precipitate or dissolve. TOUGH2/ECO2M is upwardly compatible with ECO2N and accepts ECO2N-style inputs. This report gives technical specifications of ECO2M and includes instructions for preparing input data. Code applications are illustrated by means of several sample problems, including problems that had been previously solved with TOUGH2/ECO2N.

  15. Interface model coupling in fluid dynamics: application to two-phase flows

    International Nuclear Information System (INIS)

    Galie, Th.

    2009-03-01

    This thesis is devoted to the study of interface model coupling problems in space between different models of compressible flows. We consider one-dimensional problems where the interface is sharp, fixed and separating two regions of space corresponding to the two coupled models. Our goal is to define a coupling condition at the interface and to solve numerically the coupling problem with this condition. After a state of art on the interface model coupling of hyperbolic systems of conservation laws, we propose a new coupling condition by adding in the equations of the coupled problem a measure source term at the interface. We first suppose a given constant weight associated to this source term. Two Riemann solvers are developed and one of them is based on a relaxation approach preserving equilibrium solutions of the coupled problem. This relaxation method is then used in an optimization problem, defined by several motivations at the interface, which permits to calculate a time dynamical weight. In a second part, we develop an approached Riemann solver for a two-phase two-pressure model in the particular case of a two-phase isentropic flow. Such a model contains non conservative terms that we write under the form of measure source terms. The previous relaxation method is thus extended to the case of the two-phase two-pressure model with an a priori estimation of the non conservative term contributions. The method allows us to solve, in the next and last chapter, the coupling problem of a two-fluid two-pressure model with a drift-flux model thanks to the father model approach. (authors)

  16. Quantitative measurement of normal and hydrocephalic cerebrospinal fluid flow using phase contrast cine MR imaging

    International Nuclear Information System (INIS)

    Katayama, Shinji; Asari, Shoji; Ohmoto, Takashi

    1993-01-01

    Measurements of the cerebrospinal fluid (CSF) flow using phase contrast cine magnetic resonance (MR) imaging were performed on a phantom, 12 normal subjects and 20 patients with normal pressure hydrocephalus (NPH). The phantom study demonstrated the applicability of phase contrast in quantitative measurement of the slow flow. The CSF flows of the normal subjects showed a consistent pattern with a to-and-fro movement of the flow in the anterior subarachnoid space at the C2/3 level, and they were dependent on the cardiac cycle in all subjects. However, the patients with NPH showed variable patterns of the CSF pulsatile flow and these patterns could be divided into four types according to velocity and amplitude. The amplitudes of each type were as follows: type 0 (n=1), 87.6 mm; type I (n=2), 58.2 mm (mean); type II (n=6), 48.0±5.0 mm (mean±SEM); and type III (n=11), 19.9±1.8 mm (mean±SEM). The decrease of the amplitudes correlated to a worsening of the clinical symptoms. After the shunting operation, the amplitude of to-and-fro movement of the CSF increased again in the patients with NPH who improved clinically. Some of the type III cases were reclassified type II, I and 0 and also one of the type II cases changed type I after the shunting operation. We conclude that the phase contrast cine MR imaging is a practically and clinically applicable technique for the quantitative measurement of the CSF flow. (author)

  17. Determination and theoretical analysis of supercritical fluid chromatographic retention of polycyclic aromatic hydrocarbons in a polymeric smectic phase

    International Nuclear Information System (INIS)

    Chao Yan; Martire, D.E.

    1992-01-01

    A mean-field lattice model is used to describe the partitioning of blocklike molecules between an isotropic mobile phase and an anisotropic stationary phase in chromatography by applying it to supercritical fluid retention of polycyclic aromatic hydrocarbons in a polymeric smectic phase. This concludes that the logarithm of the capacity factor (1) increases linearly with increasing reciprocal temperature, (2) decreases with increasing mobile phase density more rapidly for solute molecules with a relatively larger contact area with the mobile phase, and (3) is a linear function of the minimum area. The van't Hoff plot slope is also determined to be more negative for solute molecules with a relatively larger ratio of contact area with the stationary phase versus the mobile phase. 18 refs., 9 figs., 5 tabs

  18. Film boiling from spheres in single- and two-phase flow

    International Nuclear Information System (INIS)

    Liu, C.; Theofanous, T.G.; Yuen, W.W.

    1992-01-01

    Experimental data on film boiling heat transfer from single, inductively heated, spheres in single- and two-phase flow (saturated water and steam, respectively) are presented. In the single-phase-flow experiments water velocities ranged from 0.1 to 2.0 m/s; in the two-phase-flow experiments superficial water and steam velocities covered 0.1 to 0.6 m/s and 4 to 10 m/s, respectively. All experiments were run at atmospheric pressure and with sphere temperatures from 900C down to quenching. Limited interpretations of the single-phase- flow data are possible, but the two-phase-flow data are new and unique

  19. Hydrostatic-pressure induced phase transition of phonons in single-walled nanotubes

    International Nuclear Information System (INIS)

    Feng Peng; Meng Qingchao

    2009-01-01

    We study the effect of the hydrostatic pressure on the phonons in single-walled carbon nanotubes (SWNTs) in a magnetic field. We calculate the magnetic moments of the phonons using a functional integral technique, and find that the phonons in SWNTs undergo a pressure-induced phase transition from the paramagnetic phase to the diamagnetic phase under hydrostatic pressure 2 GPa. We explain the mechanism of generating this phase transition.

  20. Binding of monoclonal antibody to protein antigen in fluid phase or bound to solid supports

    Energy Technology Data Exchange (ETDEWEB)

    Kennel, S J

    1982-01-01

    Rat monoclonal antibody (MoAb) to fragment D (FgD) of human fibrinogen was used to characterize the direct binding of antibody to protein in solution or bound to solid supports. Purified IgG, F(ab')/sub 2/ and Fab' were prepared from ascites fluid of hybridoma 104-14B which is a fusion product of spleen cells from a rat immunized with FgD and the mouse myeloma cell line, P3-X63-Ag8. Two-dimensional electrophoresis of radioiodinated antibody preparations demonstrated the presence of hybrid immunoglobulin molecules, but only structures having rat heavy and rat light chains had active antibody combinig sites. The affinity constant for IgG as well as F(ab')/sub 2/ and Fab', 6x10/sup 9/ M/sup -1/, was identical when tested using fluid phase antigen (/sup 125/I-labeled FgD). Affinity constants determined for direct binding of iodinated IgG using FgD immobilized on solid supports showed a slight dependence on the antigen concentration used in the measurement. These values ranged from 0.5x10/sup 9/ M/sup -1/ at high antigen concentrations (1.3x10/sup -7/ M) to 9x10/sup 9/ M/sup -1/ at low antigen concentration (1.3x10/sup -10/ M). Binding constants for F(ab')/sub 2/ and Fab' gave similar results indicating that binding was homogeneous and univalent. The capacity of solid state antigen to bind antibody varied with the method used to bind FgD to the solid support. FgD bound directly to polystyrene plates was least efficient at binding labeled antibody; FgD bound to plates through intermediate carriers poly(L-lysine) was only slightly more efficient, while antigen bound to Sepharose beads by cyanogen bromide activation was the most active.

  1. Analysis of free-surface flows through energy considerations: Single-phase versus two-phase modeling.

    Science.gov (United States)

    Marrone, Salvatore; Colagrossi, Andrea; Di Mascio, Andrea; Le Touzé, David

    2016-05-01

    The study of energetic free-surface flows is challenging because of the large range of interface scales involved due to multiple fragmentations and reconnections of the air-water interface with the formation of drops and bubbles. Because of their complexity the investigation of such phenomena through numerical simulation largely increased during recent years. Actually, in the last decades different numerical models have been developed to study these flows, especially in the context of particle methods. In the latter a single-phase approximation is usually adopted to reduce the computational costs and the model complexity. While it is well known that the role of air largely affects the local flow evolution, it is still not clear whether this single-phase approximation is able to predict global flow features like the evolution of the global mechanical energy dissipation. The present work is dedicated to this topic through the study of a selected problem simulated with both single-phase and two-phase models. It is shown that, interestingly, even though flow evolutions are different, energy evolutions can be similar when including or not the presence of air. This is remarkable since, in the problem considered, with the two-phase model about half of the energy is lost in the air phase while in the one-phase model the energy is mainly dissipated by cavity collapses.

  2. A numerical model of two-phase flow at the micro-scale using the volume-of-fluid method

    Science.gov (United States)

    Shams, Mosayeb; Raeini, Ali Q.; Blunt, Martin J.; Bijeljic, Branko

    2018-03-01

    This study presents a simple and robust numerical scheme to model two-phase flow in porous media where capillary forces dominate over viscous effects. The volume-of-fluid method is employed to capture the fluid-fluid interface whose dynamics is explicitly described based on a finite volume discretization of the Navier-Stokes equations. Interfacial forces are calculated directly on reconstructed interface elements such that the total curvature is preserved. The computed interfacial forces are explicitly added to the Navier-Stokes equations using a sharp formulation which effectively eliminates spurious currents. The stability and accuracy of the implemented scheme is validated on several two- and three-dimensional test cases, which indicate the capability of the method to model two-phase flow processes at the micro-scale. In particular we show how the co-current flow of two viscous fluids leads to greatly enhanced flow conductance for the wetting phase in corners of the pore space, compared to a case where the non-wetting phase is an inviscid gas.

  3. Modeling Temperature Development of Li-ion Battery Packs using Phase Change Materials (PCM) and Fluid Flow

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu; Veje, Christian

    2014-01-01

    This paper presents a dynamic model for simulating the heat generation and the impact of Phase Change Materials (PCMs) on the maximum temperature in LiFePO4 battery cells. The model is constructed by coupling a one-dimensional electro-chemical model with a two-dimensional thermal model and fluid...

  4. High-quality single crystalline NiO with twin phases grown on sapphire substrate by metalorganic vapor phase epitaxy

    Directory of Open Access Journals (Sweden)

    Kazuo Uchida

    2012-12-01

    Full Text Available High-quality single crystalline twin phase NiO grown on sapphire substrates by metalorganic vapor phase epitaxy is reported. X-ray rocking curve analysis of NiO films grown at different temperatures indicates a minimum full width at half maximum of the cubic (111 diffraction peak of 0.107° for NiO film grown at as low as 550 °C. Detailed microstructural analysis by Φ scan X-ray diffraction and transmission electron microscopy reveal that the NiO film consists of large single crystalline domains with two different crystallographic orientations which are rotated relative to each other along the [111] axis by 60°. These single crystal domains are divided by the twin phase boundaries.

  5. Accurate prediction of complex free surface flow around a high speed craft using a single-phase level set method

    Science.gov (United States)

    Broglia, Riccardo; Durante, Danilo

    2017-11-01

    This paper focuses on the analysis of a challenging free surface flow problem involving a surface vessel moving at high speeds, or planing. The investigation is performed using a general purpose high Reynolds free surface solver developed at CNR-INSEAN. The methodology is based on a second order finite volume discretization of the unsteady Reynolds-averaged Navier-Stokes equations (Di Mascio et al. in A second order Godunov—type scheme for naval hydrodynamics, Kluwer Academic/Plenum Publishers, Dordrecht, pp 253-261, 2001; Proceedings of 16th international offshore and polar engineering conference, San Francisco, CA, USA, 2006; J Mar Sci Technol 14:19-29, 2009); air/water interface dynamics is accurately modeled by a non standard level set approach (Di Mascio et al. in Comput Fluids 36(5):868-886, 2007a), known as the single-phase level set method. In this algorithm the governing equations are solved only in the water phase, whereas the numerical domain in the air phase is used for a suitable extension of the fluid dynamic variables. The level set function is used to track the free surface evolution; dynamic boundary conditions are enforced directly on the interface. This approach allows to accurately predict the evolution of the free surface even in the presence of violent breaking waves phenomena, maintaining the interface sharp, without any need to smear out the fluid properties across the two phases. This paper is aimed at the prediction of the complex free-surface flow field generated by a deep-V planing boat at medium and high Froude numbers (from 0.6 up to 1.2). In the present work, the planing hull is treated as a two-degree-of-freedom rigid object. Flow field is characterized by the presence of thin water sheets, several energetic breaking waves and plungings. The computational results include convergence of the trim angle, sinkage and resistance under grid refinement; high-quality experimental data are used for the purposes of validation, allowing to

  6. Single-shot femtosecond-pulsed phase-shifting digital holography.

    Science.gov (United States)

    Kakue, Takashi; Itoh, Seiya; Xia, Peng; Tahara, Tatsuki; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2012-08-27

    Parallel phase-shifting digital holography is capable of three-dimensional measurement of a dynamically moving object with a single-shot recording. In this letter, we demonstrated a parallel phase-shifting digital holography using a single femtosecond light pulse whose central wavelength and temporal duration were 800 nm and 96 fs, respectively. As an object, we set spark discharge in atmospheric pressure air induced by applying a high voltage to between two electrodes. The instantaneous change in phase caused by the spark discharge was clearly reconstructed. The reconstructed phase image shows the change of refractive index of air was -3.7 × 10(-4).

  7. Debris transport evaluation during the blow-down phase of a LOCA using computational fluid dynamics

    International Nuclear Information System (INIS)

    Park, Jong Pil; Jeong, Ji Hwan; Kim, Won Tae; Kim, Man Woong; Park, Ju Yeop

    2011-01-01

    Highlights: → We conducted CFD simulation on the spreading of the coolant in the containment after a break of the hot leg. It is used to estimate the dispersion of the debris within the containment. → It was assumed that the small and fine debris is transported by the discharge flow so that a fraction of the small and fine debris transport can be estimated based on the amount of water. → The break flow was assumed to be a homogeneous two-phase mixture without phase separation. Isenthalpic expansion of the break flow was used to specify the inlet boundary condition of the break flow. → The fraction of the small and fine debris transported to the upper part is 73%; this value is close to the value calculated using 1D lumped-parameter codes by the USNRC and the KINS, respectively, while 48% more than the value shown in the NEI 04-07. - Abstract: The performance of the emergency recirculation water sump under the influence of debris accumulation following a loss-of-coolant accident (LOCA) has long been of safety concern. Debris generation and transport during a LOCA are significantly influenced by the characteristics of the ejected coolant flow. One-dimensional analyses previously have been attempted to evaluate the debris transport during the blow-down phase but the transport evaluation still has large uncertainties. In this work, a computational fluid dynamics (CFD) analysis was utilized to evaluate small and fine debris transport during the blow-down phase of a pressurized water reactor, OPR1000. The coolant ejected from the ruptured hot-leg was assumed to expand in an isenthalpic process. The transport of small and fine debris was assumed to be dominated by water-borne transport, and the transport fractions for the upper and lower parts of the containment were quantified based on the CFD analysis. It was estimated that 73% of small and fine debris is transported to the upper part of the containment. This value is close to the values estimated by nuclear

  8. Molecular theory of chromatography for blocklike solutes in isotropic stationary phases and its application to supercritical fluid chromatographic retention of PAHs

    International Nuclear Information System (INIS)

    Chao Yan; Martire, D.E.

    1992-01-01

    This report discusses a molecular theory of chromatography for blocklike solutes in isotropic stationary phases as an extension to the anisotopic phase approach. Its it applied to gas, liquid, and supercritical fluid chromatography

  9. Initial transformer sizing for single-phase residential load

    International Nuclear Information System (INIS)

    Schneider, K.C.; Hoad, R.F.

    1992-01-01

    The purchase of distribution transformers represents a significant capital investment per year for an electric utility. Choosing the correct thermal and economic size transformer can help control this investment. This paper describes a method for determining the correct economic size of distribution transformers using end-use appliance load profiles and the ANSI/IEEE Standard C57.91-1981 thermal model. Although applied only to single family and multifamily residential load in this paper, the method can be extended to other types of load such as commercial or industrial

  10. A Single Phase to Three Phase PFC Half-Bridge Converter Using BLDC Drive with SPWM Technique.

    OpenAIRE

    Srinu Duvvada; Manmadha Kumar B

    2014-01-01

    In this paper, a buck half-bridge DC-DC converter is used as a single-stage power factor correction (PFC) converter for feeding a voltage source inverter (VSI) based permanent magnet brushless DC motor (BLDC) drive. The front end of this PFC converter is a diode bridge rectifier (DBR) fed from single-phase AC mains. The BLDC is used to drive a compressor load of an air conditioner through a three-phase VSI fed from a controlled DC link voltage. The speed of the compressor is controlled to ach...

  11. A Fuzzy Logic Based Three phase Inverter with Single DC Source for Grid Connected PV System Employing Three Phase Transformer

    OpenAIRE

    Mani, venkatesan; Ramachandran, Rajeswari; N, Deverajan

    2016-01-01

    A fuzzy based three phase inverter with single DC source for grid connected photo voltaic (PV) system employing three phase transformer is presented in this paper. Space Vector Pulse Width Modulation (SVPWM) control scheme is effectively used to generate the appropriate switching sequences to the inverter switches. The intend of the fuzzy logic approach is to meet high quality output, fast response and high robustness. Finally Total Harmonics Distortion (THD) generated by the inverter is comp...

  12. Structural steady states and relaxation oscillations in a two-phase fluid under shear flow: Experiments and phenomenological model

    Science.gov (United States)

    Courbin, L.; Benayad, A.; Panizza, P.

    2006-01-01

    By means of several rheophysics techniques, we report on an extensive study of the couplings between flow and microstructures in a two-phase fluid made of lamellar (Lα) and sponge (L3) phases. Depending on the nature of the imposed dynamical parameter (stress or shear rate) and on the experimental conditions (brine salinity or temperature), we observe several different structural steady states consisting of either multilamellar droplets (with or without a long range order) or elongated (L3) phase domains. Two different astonishing phenomena, shear-induced phase inversion and relaxation oscillations, are observed. We show that (i) phase inversion is related to a shear-induced topological change between monodisperse multilamellar droplets and elongated structures and (ii) droplet size relaxation oscillations result from a shear-induced change of the surface tension between both coexisting (Lα) and (L3) phases. To explain these relaxation oscillations, we present a phenomenological model and compare its numerical predictions to our experimental results.

  13. Qualitative and quantitative analysis of different fluid phase in samples of glass beads by X-ray microtomography

    International Nuclear Information System (INIS)

    Marques, Leonardo C.; Nagata, Rodrigo; Appoloni, Carlos R.; Moreira, Anderson C.; Fernanades, Celso P.

    2011-01-01

    The X-ray microtomography has showed to be a useful tool for studies of inner structure of reservoir rocks. Moreover recent works have used this methodology to visualize different fluid phases present in these microstructures. In this paper X-ray microtomography has been applied to visualize three fluid phases, separately or simultaneously, in addition to a solid phase (glass beads). Two glass beads samples were manufactured and scanned, one with 0.8 mm (GB1) and other with 0.6 mm (GB2) diameter, respectively. The three fluid phases used were air, oil and a water-salt-potassium iodine solution. Two Skyscan scanners were used, both a 1172 model, which employs X-ray tube with W anode and cone beam. This laboratory based equipment is able to provide images of until 1 μm spatial resolution. One microtomograph is located at CENPES/PETROBRAS and has a CCD camera of 10 mega pixels resolution. It was used to measure the GB1 sample at 4.84 μm spatial resolution. The other one is located at LAMIR/UFPR and has a CCD camera of 11 mega pixels resolution. It was used to measure the GB2 sample at 4.99 μm spatial resolution. GB1 sample was set up with three fluid phases and presented 38.0 (2.7) % of total porosity before fluid presence and 3.5 % and 19.8 %, as lower and higher average porosity values, respectively, after to be filled with them. GB2 sample was set up with oil and water-salt-potassium iodine solution separated. It presented 36.7 (1.9) % of total porosity when dried, 18.7 (2.0) % when filled with oil and 0 % when filled with the solution. The 2D images clearly show the presence of the solution in addition to the air and solid phases. They also show that the presence of oil phase is less clear than the solution. When all the phases are present together in the sample it is possible to differentiate all of them. Individual 3D images are shown for each phase present in the sample. The 3D image containing all the phases is also shown. (author)

  14. An Overview of SBIR Phase 2 In-Space Propulsion and Cryogenic Fluids Management

    Science.gov (United States)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing Areas in In-Space Propulsion and Cryogenic Fluids Management which is one of six core competencies at NASA Glenn Research Center. There are nineteen technologies featured with emphasis on a wide spectrum of applications such as high-performance Hall thruster support system, thruster discharge power converter, high-performance combustion chamber, ion thruster design tool, green liquid monopropellant thruster, and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  15. Centrifuge - dewatering of oil sand fluid tailings: phase 2 field-scale test

    Energy Technology Data Exchange (ETDEWEB)

    Seto, Jack T.C. [BGC Engineering Inc (Canada); O' Kane, Mike [O' Kane Consultants Inc (Canada); Donahue, Robert [Applied Geochemical Solutions Engineering (Canada); Lahaie, Rick [Syncrude Canada Ltd (Canada)

    2011-07-01

    In order to reduce the accumulation of oil sand fluid fine tailings (FFT) and to create trafficable surfaces for reclamation, Syncrude Canada Ltd. has been studying several tailings technologies. Centrifuge-dewatering is one such technology. This paper discusses the phase 2 field-scale tests for centrifuge-dewatering of oil sand FFT. In centrifuge-dewatering, FFT is diluted and treated with flocculant, then processed through a centrifuge plant and the high-density underflow is transported to a tailings deposit. This technology has evolved since 2005 from laboratory bench scale tests. More than 10,000 cubic meters of centrifuge cake was treated, produced and transported to ten different deposits over a 12-week period from August to October 2010. The amount of solids in FFT was increased from 30% to 50% by centrifuging. Sampled deposits were tested and instrumented for in situ strength. It can be concluded that the deposits can be strengthened and densified by natural dewatering processes like freeze-thaw action and evaporative drying.

  16. Theoretical and numerical investigations of inverse patchy colloids in the fluid phase

    International Nuclear Information System (INIS)

    Kalyuzhnyi, Yurij V.; Bianchi, Emanuela; Ferrari, Silvano; Kahl, Gerhard

    2015-01-01

    We investigate the structural and thermodynamic properties of a new class of patchy colloids, referred to as inverse patchy colloids (IPCs) in their fluid phase via both theoretical methods and simulations. IPCs are nano- or micro- meter sized particles with differently charged surface regions. We extend conventional integral equation schemes to this particular class of systems: our approach is based on the so-called multi-density Ornstein-Zernike equation, supplemented with the associative Percus-Yevick approximation (APY). To validate the accuracy of our framework, we compare the obtained results with data extracted from NpT and NVT Monte Carlo simulations. In addition, other theoretical approaches are used to calculate the properties of the system: the reference hypernetted-chain (RHNC) method and the Barker-Henderson thermodynamic perturbation theory. Both APY and RHNC frameworks provide accurate predictions for the pair distribution functions: APY results are in slightly better agreement with MC data, in particular at lower temperatures where the RHNC solution does not converge

  17. Improved solid-phase extraction method for systematic toxicological analysis in biological fluids.

    Science.gov (United States)

    Soriano, T; Jurado, C; Menéndez, M; Repetto, M

    2001-03-01

    A method for the simultaneous qualitative and quantitative determination of drugs of abuse (opiates, cocaine, or amphetamines) and prescribed drugs (tricyclic antidepressants, phenotiazines, benzodiazepines, etc.) in biological fluids--blood, urine, bile, and gastric contents--was developed. This procedure involves solid-phase extraction with Bond-Elut Certify columns followed by analysis by gas chromatography-nitrogen-phosphorus detection (GC-NPD) and confirmation by gas chromatography-mass spectrometry (GC-MS), after derivatization, when necessary. Pretreatment was performed on all samples: sonication for 15 min plus enzymatic hydrolysis with beta-glucuronidase in urine. With respect to the internal standards, nalorphine and trihexylamine were used for basic substances, allobarbital for acidic drugs, and prazepam for benzodiazepines. Acidic and basic compounds were extracted from different aliquots of samples at different pH levels: 6-6.5 for the acidic and neutral and 8-8.5 for the basic and the benzodiazepines. Several areas of experimental design were considered in the process of method optimization. These included internal standards, pH, sonication, flow rate and washing solvents. It was found that systematic analysis could be reliably performed using optimized extraction conditions. The recovery rates for the compounds tested were always higher than 61.02%.

  18. Fluid Phase Lipid Areas and Bilayer Thicknesses of Commonly Used Phosphatidylcholines as a Function of Temperature

    International Nuclear Information System (INIS)

    Kucerka, Norbert; Nieh, Mu-Ping; Katsaras, John

    2011-01-01

    The structural parameters of fluid phase bilayers composed of phosphatidylcholines with fully saturated, mixed, and branched fatty acid chains, at several temperatures, have been determined by simultaneously analyzing small-angle neutron and X-ray scattering data. Bilayer parameters, such as area per lipid and overall bilayer thickness have been obtained in conjunction with intrabilayer structural parameters (e.g. hydrocarbon region thickness). The results have allowed us to assess the effect of temperature and hydrocarbon chain composition on bilayer structure. For example, we found that for all lipids there is, not surprisingly, an increase in fatty acid chain trans-gauche isomerization with increasing temperature. Moreover, this increase in trans-gauche isomerization scales with fatty acid chain length in mixed chain lipids. However, in the case of lipids with saturated fatty acid chains, trans-gauche isomerization is increasingly tempered by attractive chain-chain van der Waals interactions with increasing chain length. Finally, our results confirm a strong dependence of lipid chain dynamics as a function of double bond position along fatty acid chains.

  19. Qualification of code-Saturne for thermal-hydraulics single phase nuclear applications

    International Nuclear Information System (INIS)

    Archambeau, F.; Bechaud, C.; Gest, B.; Martin, A.; Sakiz, M.

    2003-01-01

    Code-Saturne is a general finite volume CFD (computational fluid dynamics) code developed by Electricite de France (EDF) under quality assurance for 2- and 3-dimensional simulations, laminar and turbulent flows, conjugate heat transfer (coupling with thermal code SYRTHES), including combustion modelling and a Lagrangian module. A very large range of meshes can be used. The solver relies on a finite volume method on arbitrary meshes (hybrid, with hanging nodes, any type of element). All variables are located at the cell centres. The solver is time marching, with a predictor-corrector scheme for Navier-Stokes equations. Standard Reynolds Average Navier-Stokes modelling (RANS) is included (k-epsilon, RSM). Code-Saturne is used by EDF in various industrial fields such as process engineering, aeraulics, combustion and nuclear applications. The present paper describes the qualification phase carried out during 2001 for single-phase nuclear applications. Indeed, once an industrial product has been released and validated, it is of major importance, especially in this particular field related to safety matters, to demonstrate the ability of the code to help engineers produce satisfactory conclusions to industrial problems. In coherence with analyses and best practice guidelines such as those published by the ERCOFTAC Special Interest Group, it seemed important to base the qualification phase on well defined and documented experimental facilities, sufficiently complex to be representative of industrial studies. Much attention has been devoted to evaluating sensitivity to numerical parameters such as grid refinement, time step... Moreover, the qualification studies have been carried out in real-life conditions, that is in limited time, with industrial limitations on the number of grid cells, and by the teams usually producing such studies, so as to integrate a real industrial process in the qualification phase. Two test cases chosen to assess certain types of flows in PWR

  20. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a tunable single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  1. A High Energy and High Efficiency Spectral Shaping Single Frequency Fiber Laser, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase II project proposes a single frequency high energy fiber laser system for coherent Lidar systems for remote sensing. Current state-of-art...

  2. A Novel Model Predictive Control for Single-Phase Grid-Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2017-01-01

    Single-phase grid-connected inverters with LCL filter are widely used to connect photovoltaic systems to the utility grid. Among the existing control schemes, predictive control methods are faster and more accurate but also more complicated to implement. Recently, the Model Predictive Control (MPC......) algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the MPC approach, all switching states are considered in each switching period to achieve the control objectives. However, since the number of switching states in single-phase inverters is small......, the inverter output current has a high Total Harmonic Distortions (THD). In order to reduce this, this paper presents an improved MPC for single-phase grid-connected inverters. In the proposed approach, the switching algorithm is changed and the number of the switching states is increased by means of virtual...

  3. Standard Specification for Sampling Single-Phase Geothermal Liquid or Steam for Purposes of Chemical Analysis

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1983-01-01

    1.1 This specification covers the basic requirements for equipment to be used for the collection of uncontaminated and representative samples from single-phase geothermal liquid or steam. Geopressured liquids are included. See Fig 1.

  4. High Power Compact Single-Frequency Volume Bragg Er-Doped Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this NASA SBIR Phase I proposal is to develop the prototype of a compact single-frequency mode one longitudinal and one transverse mode laser...

  5. Increased levels of proteins of the acute inflammatory phase in the peritoneal fluid of women with advanced stages of endometriosis.

    Science.gov (United States)

    Polak, Grzegorz; Barczyński, Bartłomiej; Bednarek, Wiesława; Kwaśniewski, Wojciech; Wertell, Iwona; Derewianka-Polak, Magdalena; Makara-Studzińska, Marta; Kotarski, Jan

    2015-06-01

    Most investigators agree that endometriosis is associated with a state of subclinical, non-infectious peritoneal inflammation. The objective of the study was to assess concentrations of two markers of the acute inflammatory phase proteins, haptoglobin and ceruloplasmin, in peritoneal fluid of endometriotic women. 229 women who underwent diagnostic or therapeutic laparoscopy were included in the study Minimal, mild, moderate and severe endometriosis according to ASRM was confirmed in 119 women (study groups), whereas 110 patients suffered from simple serous or dermoid ovarian cysts (reference groups). Haptoglobin and ceruloplasmin concentrations in the peritoneal fluid samples aspirated during laparoscopy were measured using commercially available radial immunodiffusion kits. The concentration of haptoglobin in the peritoneal fluid of women with endometriosis was significantly higher as compared to patients with serous and dermoid ovarian cysts. Significantly higher haptoglobin level was observed in patients with severe and moderate endometriosis as compared to women from both reference groups. No significant difference in the peritoneal fluid ceruloplasmin levels was found between patients with endometriosis and women from reference groups. However, it was noted that ceruloplasmin levels are higher in the subgroup of patients with severe endometriosis as compared to both reference groups and women with mild disease. Our results support the hypothesis that endometriosis is associated with subclinical inflammation within the peritoneal cavity It may be speculated that pro-inflammatory stimuli strong enough to cause an increase in acute inflammatory phase proteins peritoneal fluid concentrations are observed only in the advanced stages of the disease.

  6. A Gas-Kinetic Method for Hyperbolic-Elliptic Equations and Its Application in Two-Phase Fluid Flow

    Science.gov (United States)

    Xu, Kun

    1999-01-01

    A gas-kinetic method for the hyperbolic-elliptic equations is presented in this paper. In the mixed type system, the co-existence and the phase transition between liquid and gas are described by the van der Waals-type equation of state (EOS). Due to the unstable mechanism for a fluid in the elliptic region, interface between the liquid and gas can be kept sharp through the condensation and evaporation process to remove the "averaged" numerical fluid away from the elliptic region, and the interface thickness depends on the numerical diffusion and stiffness of the phase change. A few examples are presented in this paper for both phase transition and multifluid interface problems.

  7. Single dose pharmacokinetics of fenspiride hydrochloride: phase I clinical trial.

    Science.gov (United States)

    Montes, B; Catalan, M; Roces, A; Jeanniot, J P; Honorato, J M

    1993-01-01

    The absolute bioavailability of fenspiride has been studied in twelve healthy volunteers. It was administered IV and orally in single doses of 80 mg fenspiride hydrochloride according to a randomised crossover pattern. Following IV administration, the plasma clearance of fenspiride was about 184 ml.min-1, and its apparent volume of distribution was moderately large (215 l). When given orally as a tablet, fenspiride exhibited fairly slow ab- sorption; the maximum plasma concentration (206 ng.ml-1) was achieved 6 h after administration. The absolute bioavailability was almost complete (90%). The tablet had slow release characteristics. The elimination half-life obtained from the plasma data was 14 to 16 h independent of the route of administration.

  8. Thermal regulation in terrestrial environment using a two-phase fluid loop with capillary pumping; Regulation thermique en environnement terrestre par boucle fluide diphasique a pompage capillaire

    Energy Technology Data Exchange (ETDEWEB)

    Butto, C [Universite Paul Sabatier, LESETH, 31 - Toulouse (France)

    1997-12-31

    Two-phase fluid loops with capillary pumping are particularly interesting silent devices which allow energy savings and do not create any noise pollution (no mechanical vibrations). In terrestrial environment, the gravity field, when judiciously used, allows to improve their performances and thus, their use in thermal regulation of big computers, power electronic components, transformers, etc, is particularly interesting. In this study, the main results concerning the functioning of such a loop in the gravity field are presented and used to highlight the conditions that allow to take advantage of this field and the improvements obtained. (J.S.) 5 refs.

  9. Thermal regulation in terrestrial environment using a two-phase fluid loop with capillary pumping; Regulation thermique en environnement terrestre par boucle fluide diphasique a pompage capillaire

    Energy Technology Data Exchange (ETDEWEB)

    Butto, C. [Universite Paul Sabatier, LESETH, 31 - Toulouse (France)

    1996-12-31

    Two-phase fluid loops with capillary pumping are particularly interesting silent devices which allow energy savings and do not create any noise pollution (no mechanical vibrations). In terrestrial environment, the gravity field, when judiciously used, allows to improve their performances and thus, their use in thermal regulation of big computers, power electronic components, transformers, etc, is particularly interesting. In this study, the main results concerning the functioning of such a loop in the gravity field are presented and used to highlight the conditions that allow to take advantage of this field and the improvements obtained. (J.S.) 5 refs.

  10. Reducing Electromagnetic Interference in a Grid Tied Single Phase Power Inverter

    Science.gov (United States)

    2016-09-01

    With the growing demand for a reliable electrical grid, backup power supplies and energy management systems are a necessity. Systems such as server...ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER INVERTER by Jason Hassan Valiani September 2016 Thesis Advisor: Giovanna Oriti...3. REPORT TYPE AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE REDUCING ELECTROMAGNETIC INTERFERENCE IN A GRID TIED SINGLE PHASE POWER

  11. The scaling of burnout data for a single fluid at a fixed pressure

    International Nuclear Information System (INIS)

    Kirby, G.J.

    1966-12-01

    The success of the scaling factor concept in linking burnout measurements made in two different fluids has been amply demonstrated. This memorandum investigates the possibility of linking measurements made on two different systems in the same fluid. It seems that good accuracy may be obtained for systems whose linear dimensions differ by as much as a factor of two; this offers the possibility of saving very substantial amounts of power in testing reactor fuel element. A novel conclusion is that systems do not need to be geometrically similar in order to be linked by scaling factors. (author)

  12. An adaptive meshfree method for phase-field models of biomembranes. Part II: A Lagrangian approach for membranes in viscous fluids

    OpenAIRE

    Peco, C.; Rosolen, A.; Arroyo, M.

    2013-01-01

    We present a Lagrangian phase-field method to study the low Reynolds number dynamics of vesicles embedded in a viscous fluid. In contrast to previous approaches, where the field variables are the phase-field and the fluid velocity, here we exploit the fact that the phasefield tracks a material interface to reformulate the problem in terms of the Lagrangian motion of a background medium, containing both the biomembrane and the fluid. We discretize the equations in space with maximum-entr...

  13. Searching for Next Single-Phase High-Entropy Alloy Compositions

    Directory of Open Access Journals (Sweden)

    David E. Alman

    2013-10-01

    Full Text Available There has been considerable technological interest in high-entropy alloys (HEAs since the initial publications on the topic appeared in 2004. However, only several of the alloys investigated are truly single-phase solid solution compositions. These include the FCC alloys CoCrFeNi and CoCrFeMnNi based on 3d transition metals elements and BCC alloys NbMoTaW, NbMoTaVW, and HfNbTaTiZr based on refractory metals. The search for new single-phase HEAs compositions has been hindered by a lack of an effective scientific strategy for alloy design. This report shows that the chemical interactions and atomic diffusivities predicted from ab initio molecular dynamics simulations which are closely related to primary crystallization during solidification can be used to assist in identifying single phase high-entropy solid solution compositions. Further, combining these simulations with phase diagram calculations via the CALPHAD method and inspection of existing phase diagrams is an effective strategy to accelerate the discovery of new single-phase HEAs. This methodology was used to predict new single-phase HEA compositions. These are FCC alloys comprised of CoFeMnNi, CuNiPdPt and CuNiPdPtRh, and HCP alloys of CoOsReRu.

  14. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network.

    Science.gov (United States)

    Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan

    2017-08-13

    Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  15. Directed self-assembly of liquid crystalline blue-phases into ideal single-crystals

    Science.gov (United States)

    Martínez-González, Jose A.; Li, Xiao; Sadati, Monirosadat; Zhou, Ye; Zhang, Rui; Nealey, Paul F.; de Pablo, Juan J.

    2017-06-01

    Chiral nematic liquid crystals are known to form blue phases--liquid states of matter that exhibit ordered cubic arrangements of topological defects. Blue-phase specimens, however, are generally polycrystalline, consisting of randomly oriented domains that limit their performance in applications. A strategy that relies on nano-patterned substrates is presented here for preparation of stable, macroscopic single-crystal blue-phase materials. Different template designs are conceived to exert control over different planes of the blue-phase lattice orientation with respect to the underlying substrate. Experiments are then used to demonstrate that it is indeed possible to create stable single-crystal blue-phase domains with the desired orientation over large regions. These results provide a potential avenue to fully exploit the electro-optical properties of blue phases, which have been hindered by the existence of grain boundaries.

  16. Results of single borehole hydraulic testing in the Mizunami Underground Research Laboratory project. Phase 2

    International Nuclear Information System (INIS)

    Daimaru, Shuji; Takeuchi, Ryuji; Onoe, Hironori; Saegusa, Hiromitsu

    2012-09-01

    This report summarize the results of the single borehole hydraulic tests of 79 sections conducted as part of the Construction phase (Phase 2) in the Mizunami Underground Research Laboratory (MIU) Project. The details of each test (test interval depth, geology, etc.) as well as the interpreted hydraulic parameters and analytical method used are presented in this report. (author)

  17. Dynamics Assessment of Grid-Synchronization Algorithms for Single-Phase Grid-Connected Converters

    DEFF Research Database (Denmark)

    Han, Yang; Luo, Mingyu; Guerrero, Josep M.

    2015-01-01

    Several advanced phase-lock-loop (PLL) algorithms have been proposed for single-phase power electronic systems. Among these algorithms, the orthogonal signal generators (OSGs) are widely utilized to generate a set of in-quadrature signals, owing to its benefit of simple digital implementation and...

  18. Comparative Performance Evaluation of Orthogonal-Signal-Generators-Based Single-Phase PLL Algorithms

    DEFF Research Database (Denmark)

    Han, Yang; Luo, Mingyu; Zhao, Xin

    2016-01-01

    The orthogonal signal generator based phase-locked loops (OSG-PLLs) are among the most popular single-phase PLLs within the areas of power electronics and power systems, mainly because they are often easy to be implement and offer a robust performance against the grid disturbances. The main aim o...

  19. Gaussian approximation to single particle correlations at and below the picosecond scale for Lennard-Jones and nanoparticle fluids

    International Nuclear Information System (INIS)

    Van Zon, Ramses; Ashwin, S S; Cohen, E G D

    2008-01-01

    To describe short time (picosecond) and small scale (nanometre) transport in fluids, a Green's function approach was recently developed. This approach relies on an expansion of the distribution of single particle displacements around a Gaussian function, yielding an infinite series of correction terms. Applying a recent theorem (van Zon and Cohen 2006 J. Stat. Phys. 123 1–37) shows that for sufficiently small times the terms in this series become successively smaller, so that truncating the series near or at the Gaussian level might provide a good approximation. In this paper, we derive a theoretical estimate for the time scale at which truncating the series at or near the Gaussian level could be supposed to be accurate for equilibrium nanoscale systems. In order to numerically estimate this time scale, the coefficients for the first few terms in the series are determined in computer simulations for a Lennard-Jones (LJ) fluid, an isotopic LJ mixture and a suspension of a LJ-based model of nanoparticles in a LJ fluid. The results suggest that for LJ fluids an expansion around a Gaussian is accurate at time scales up to a picosecond, while for nanoparticles in suspension (a nanofluid), the characteristic time scale up to which the Gaussian is accurate becomes of the order of 5–10 ps. (invited article)

  20. A two-system, single-analysis, fluid-structure interaction technique for modelling abdominal aortic aneurysms.

    Science.gov (United States)

    Kelly, S C; O'Rourke, M J

    2010-01-01

    This work reports on the implementation and validation of a two-system, single-analysis, fluid-structure interaction (FSI) technique that uses the finite volume (FV) method for performing simulations on abdominal aortic aneurysm (AAA) geometries. This FSI technique, which was implemented in OpenFOAM, included fluid and solid mesh motion and incorporated a non-linear material model to represent AAA tissue. Fully implicit coupling was implemented, ensuring that both the fluid and solid domains reached convergence within each time step. The fluid and solid parts of the FSI code were validated independently through comparison with experimental data, before performing a complete FSI simulation on an idealized AAA geometry. Results from the FSI simulation showed that a vortex formed at the proximal end of the aneurysm during systolic acceleration, and moved towards the distal end of the aneurysm during diastole. Wall shear stress (WSS) values were found to peak at both the proximal and distal ends of the aneurysm and remain low along the centre of the aneurysm. The maximum von Mises stress in the aneurysm wall was found to be 408kPa, and this occurred at the proximal end of the aneurysm, while the maximum displacement of 2.31 mm occurred in the centre of the aneurysm. These results were found to be consistent with results from other FSI studies in the literature.

  1. An Automated High Aspect Ratio Mesher for Computational Fluid Dynamics, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Computational fluid dynamics (CFD) simulations are routinely used while designing, analyzing, and optimizing air- and spacecraft. An important component of CFD...

  2. Single Phase Transformer-less Buck-Boost Inverter with Zero Leakage Current for PV Systems

    DEFF Research Database (Denmark)

    Mostaan, Ali; Abdelhakim, Ahmed; N. Soltani, Mohsen

    2017-01-01

    In this paper, a novel single-stage single-phase transformer-less buck-boost inverter is proposed, in which a reduced number of passive components is used. The proposed inverter combines the conventional buck, boost, and buck-boost converters in one converter in order to obtain a sinusoidal output...

  3. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  4. A Direct Maximum Power Point Tracking Method for Single-Phase Grid Connected PV Inverters

    DEFF Research Database (Denmark)

    EL Aamri, Faicel; Maker, Hattab; Sera, Dezso

    2018-01-01

    in dynamic conditions, especially in low irradiance when the measurement of signals becomes more sensitive to noise. The proposed MPPT is designed for single-phase single-stage grid-connected PV inverters, and is based on estimating the instantaneous PV power and voltage ripples, using second...

  5. Fully tunable 360° microwave photonic phase shifter based on a single semiconductor optical amplifier.

    Science.gov (United States)

    Sancho, Juan; Lloret, Juan; Gasulla, Ivana; Sales, Salvador; Capmany, José

    2011-08-29

    A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

  6. Single-phase cross-mixing measurements in a 4 x 4 rod bundle

    International Nuclear Information System (INIS)

    Yloenen, Arto; Bissels, Wilhelm-Martin; Prasser, Horst-Michael

    2011-01-01

    Highlights: → The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry. → Quantitative information on the turbulent dispersion of the fluid was obtained. → In full spatial and temporal resolution, the data is interesting for the unsteady CFD validation. - Abstract: The wire-mesh sensor technique has been successfully introduced into a fuel rod bundle geometry for the first time. In this context, a dedicated test facility (SUBFLOW) has been designed and constructed at Paul Scherrer Institut (PSI) in a co-operation with the Swiss Federal Institute of Technology (ETH Zuerich). Two wire-mesh sensors designed and built in-house were installed in the upper part of the vertical test section of SUBFLOW, and single-phase experiments on the turbulent mass exchange between neighboring sub-channels were performed. For this purpose, salt tracer was injected locally in one of the sub-channels and conductivity distributions in the bundle measured by the wire-mesh sensor. Both flow rate and distance from the injection point were varied. The latter was achieved by using injection nozzles at different heights. In this way, the sensor located in the upper part of the channel could be used to characterize the progress of the mixing along the flow direction, and the degree of cross-mixing assessed using the quantity of tracer arriving in the neighboring sub-channels. Fluctuations of the tracer concentration in time were used for statistical evaluations, such as the calculation of standard deviations and two-point correlations.

  7. Fabrication of single phase 2D homologous perovskite microplates by mechanical exfoliation

    Science.gov (United States)

    Li, Junze; Wang, Jun; Zhang, Yingjun; Wang, Haizhen; Lin, Gaoming; Xiong, Xuan; Zhou, Weihang; Luo, Hongmei; Li, Dehui

    2018-04-01

    The two-dimensional (2D) Ruddlesden-Popper type perovskites have attracted intensive interest for their great environmental stability and various potential optoelectronic applications. Fundamental understanding of the photophysical and electronic properties of the 2D perovskites with pure single phase is essential for improving the performance of the optoelectronic devices and designing devices with new architectures. Investigating the optical and electronic properties of these materials with pure single phase is required to obtain pure single phase 2D perovskites. Here, we report on an alternative approach to fabricate (C4H9NH3)2(CH3NH3) n-1Pb n I3n+1 microplates with pure single n-number perovskite phase for n  >  2 by mechanical exfoliation. Micro-photoluminescence and absorption spectroscopy studies reveal that the as-synthesized 2D perovskite plates for n  >  2 are comprised by dominant n-number phase and small inclusions of hybrid perovskite phases with different n values, which is supported by excitation power dependent photoluminescence. By mechanical exfoliation method, 2D perovskite microplates with the thickness of around 20 nm are obtained, which surprisingly have single n-number perovskite phase for n  =  2-5. In addition, we have demonstrated that the exfoliated 2D perovskite microplates can be integrated with other 2D layered materials such as boron nitride, and are able to be transferred to prefabricated electrodes for photodetections. Our studies not only provide a strategy to prepare 2D perovskites with a single n-number perovskite phase allowing us to extract the basic optical and electronic parameters of pure phase perovskites, but also demonstrate the possibility to integrate the 2D perovskites with other 2D layered materials to extend the device’s functionalities.

  8. LIDAR forest inventory with single-tree, double- and single-phase procedures

    Science.gov (United States)

    Robert C. Parker; David L. Evans

    2009-01-01

    Light Detection and Ranging (LIDAR) data at 0.5- to 2-m postings were used with doublesample, stratified inventory procedures involving single-tree attribute relationships in mixed, natural, and planted species stands to yield sampling errors (one-half the confidence interval expressed as a percentage of the mean) ranging from ±2.1 percent to ±11.5...

  9. A single grain approach applied to modelling recrystallization kinetics in a single-phase metal

    NARCIS (Netherlands)

    Chen, S.P.; Zwaag, van der S.

    2004-01-01

    A comprehensive model for the recrystallization kinetics is proposed which incorporates both microstructure and the textural components in the deformed state. The model is based on the single-grain approach proposed previously. The influence of the as-deformed grain orientation, which affects the

  10. Performance Evaluation of Low/Zero Voltage Ride-Through Operations for Single-Stage Single-Phase Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zhang, Zhen; Yang, Yongheng; Blaabjerg, Frede

    2017-01-01

    With the fast development of distributed power generations, stability and security have attracted extensive attention in the recent years. As a representative of clean energies, Photovoltaic (PV) systems have been installed extensively worldwide. This drives grid-connected requirements...... to be continuously updated. In current active grid requirements/codes, PV systems should be more intelligent in the considerations of the grid stability, reliability and fault protection. In this paper, two control strategies (i.e., the single-phase PQ control and power phase-angle control) are evaluated for grid...

  11. X-ray quality increasing system controlled by single-chip microcomputer in single phase fluoroscopy unit

    International Nuclear Information System (INIS)

    Wang Qiaolin; Gu Hongmei

    2004-01-01

    Objective: To decrease the amount of radiation that doctor and patient receives by increasing X-ray quality. Methods: Using Single-chip Microcomputer technology, test and modulate AC(Alternating Current) from high voltage generator by IGBT. X-ray tube generates X-rays only at high energy area. Thus the amount of radiation decreases. Results: The tube current decreases remarkably and the amount of radiation that doctor and patient receives decreases effectively. Conclusion: the system can effectively decrease the amount of radiation and is widely applicable to the upgrade of all kinds of single phase X-ray units. (authors)

  12. Nucleate pool boiling, film boiling and single-phase free convection at pressures up to the critical state. Part I: Integral heat transfer for horizontal copper cylinders

    Energy Technology Data Exchange (ETDEWEB)

    Gorenflo, Dieter; Baumhoegger, Elmar; Windmann, Thorsten; Herres, Gerhard [Institut fuer Energie- und Verfahrenstechnik, Universitaet Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany)

    2010-11-15

    Transcritical working cycles for refrigerants have led to increased interest in heat transfer near the Critical State. In general, experimental results for this region differ significantly from those far from it because some fluid properties vary much more there than at a greater distance. In this paper, measurements for two-phase and single-phase free convective heat transfer from an electrically heated copper tube with 25 mm O.D. to refrigerant R125 are discussed for fluid states very close to the Critical Point and far from it. It is shown that heat transfer for film boiling slightly below and for free convection slightly above the critical pressure is very similar. The new - and also previous - experimental data for nucleate boiling, film boiling, and single-phase free convection are compared with calculated results between atmospheric and critical pressure. It can be concluded that the Principle of Corresponding States in its simplest form is very well suited to transfer the results to other refrigerants. In Part II, particular attention will be given to a minimum superheat for nucleate boiling and a maximum superheat for film boiling and single-phase free convection within the circumferential variation of the isobaric wall superheat on the lower parts of the tube. (author)

  13. Similarity analysis and scaling criteria for LWRs under single-phase and two-phase natural circulation

    International Nuclear Information System (INIS)

    Ishii, M.; Kataoka, I.

    1983-03-01

    Scaling criteria for a natural circulation loop under single phase and two-phase flow conditions have been derived. For a single phase case the continuity, integral momentum, and energy equations in one-dimensional area average forms have been used. From this, the geometrical similarity groups, friction number, Richardson number, characteristic time constant ratio, Biot number, and heat source number are obtained. The Biot number involves the heat transfer coefficient which may cause some difficulties in simulating the turbulent flow regime. For a two-phase flow case, the similarity groups obtained from a perturbation analysis based on the one-dimensional drift-flux model have been used. The physical significance of the phase change number, subcooling number, drift-flux number, friction number are discussed and conditions imposed by these groups are evaluated. In the two-phase flow case, the critical heat flux is one of the most important transients which should be simulated in a scale model. The above results are applied to the LOFT facility in case of a natural circulation simulation. Some preliminary conclusions on the feasibility of the facility have been obtained

  14. Similarity analysis and scaling criteria for LWRs under single-phase and two-phase natural circulation

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, M.; Kataoka, I.

    1983-03-01

    Scaling criteria for a natural circulation loop under single phase and two-phase flow conditions have been derived. For a single phase case the continuity, integral momentum, and energy equations in one-dimensional area average forms have been used. From this, the geometrical similarity groups, friction number, Richardson number, characteristic time constant ratio, Biot number, and heat source number are obtained. The Biot number involves the heat transfer coefficient which may cause some difficulties in simulating the turbulent flow regime. For a two-phase flow case, the similarity groups obtained from a perturbation analysis based on the one-dimensional drift-flux model have been used. The physical significance of the phase change number, subcooling number, drift-flux number, friction number are discussed and conditions imposed by these groups are evaluated. In the two-phase flow case, the critical heat flux is one of the most important transients which should be simulated in a scale model. The above results are applied to the LOFT facility in case of a natural circulation simulation. Some preliminary conclusions on the feasibility of the facility have been obtained.

  15. Simultaneous fluid-flow, heat-transfer and solid-stress computation in a single computer code

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, D B [Concentration Heat and Momentum Ltd, London (United Kingdom)

    1998-12-31

    Computer simulation of flow- and thermally-induced stresses in mechanical-equipment assemblies has, in the past, required the use of two distinct software packages, one to determine the forces and the temperatures, and the other to compute the resultant stresses. The present paper describes how a single computer program can perform both tasks at the same time. The technique relies on the similarity of the equations governing velocity distributions in fluids to those governing displacements in solids. The same SIMPLE-like algorithm is used for solving both. Applications to 1-, 2- and 3-dimensional situations are presented. It is further suggested that Solid-Fluid-Thermal, ie SFT analysis may come to replace CFD on the one hand and the analysis of stresses in solids on the other, by performing the functions of both. (author) 7 refs.

  16. Simultaneous fluid-flow, heat-transfer and solid-stress computation in a single computer code

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, D.B. [Concentration Heat and Momentum Ltd, London (United Kingdom)

    1997-12-31

    Computer simulation of flow- and thermally-induced stresses in mechanical-equipment assemblies has, in the past, required the use of two distinct software packages, one to determine the forces and the temperatures, and the other to compute the resultant stresses. The present paper describes how a single computer program can perform both tasks at the same time. The technique relies on the similarity of the equations governing velocity distributions in fluids to those governing displacements in solids. The same SIMPLE-like algorithm is used for solving both. Applications to 1-, 2- and 3-dimensional situations are presented. It is further suggested that Solid-Fluid-Thermal, ie SFT analysis may come to replace CFD on the one hand and the analysis of stresses in solids on the other, by performing the functions of both. (author) 7 refs.

  17. Two-Phase Flow in Wire Coating with Heat Transfer Analysis of an Elastic-Viscous Fluid

    Directory of Open Access Journals (Sweden)

    Zeeshan Khan

    2016-01-01

    Full Text Available This work considers two-phase flow of an elastic-viscous fluid for double-layer coating of wire. The wet-on-wet (WOW coating process is used in this study. The analytical solution of the theoretical model is obtained by Optimal Homotopy Asymptotic Method (OHAM. The expression for the velocity field and temperature distribution for both layers is obtained. The convergence of the obtained series solution is established. The analytical results are verified by Adomian Decomposition Method (ADM. The obtained velocity field is compared with the existing exact solution of the same flow problem of second-grade fluid and with analytical solution of a third-grade fluid. Also, emerging parameters on the solutions are discussed and appropriate conclusions are drawn.

  18. Multiparticle imaging technique for two-phase fluid flows using pulsed laser speckle velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, T.A.

    1992-12-01

    The practical use of Pulsed Laser Velocimetry (PLV) requires the use of fast, reliable computer-based methods for tracking numerous particles suspended in a fluid flow. Two methods for performing tracking are presented. One method tracks a particle through multiple sequential images (minimum of four required) by prediction and verification of particle displacement and direction. The other method, requiring only two sequential images uses a dynamic, binary, spatial, cross-correlation technique. The algorithms are tested on computer-generated synthetic data and experimental data which was obtained with traditional PLV methods. This allowed error analysis and testing of the algorithms on real engineering flows. A novel method is proposed which eliminates tedious, undersirable, manual, operator assistance in removing erroneous vectors. This method uses an iterative process involving an interpolated field produced from the most reliable vectors. Methods are developed to allow fast analysis and presentation of sets of PLV image data. Experimental investigation of a two-phase, horizontal, stratified, flow regime was performed to determine the interface drag force, and correspondingly, the drag coefficient. A horizontal, stratified flow test facility using water and air was constructed to allow interface shear measurements with PLV techniques. The experimentally obtained local drag measurements were compared with theoretical results given by conventional interfacial drag theory. Close agreement was shown when local conditions near the interface were similar to space-averaged conditions. However, theory based on macroscopic, space-averaged flow behavior was shown to give incorrect results if the local gas velocity near the interface as unstable, transient, and dissimilar from the average gas velocity through the test facility.

  19. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2013-01-01

    Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  20. Pleural space infections after image-guided percutaneous drainage of infected intraabdominal fluid collections: a retrospective single institution analysis.

    Science.gov (United States)

    Avella, Diego M; Toth, Jennifer W; Reed, Michael F; Gusani, Niraj J; Kimchi, Eric T; Mahraj, Rickeshvar P; Staveley-O'Carroll, Kevin F; Kaifi, Jussuf T

    2015-04-11

    Percutaneous drainage of infected intraabdominal fluid collections is preferred over surgical drainage due to lower morbidity and costs. However, it can be a challenging procedure and catheter insertion carries the potential to contaminate the pleural space from the abdomen. This retrospective analysis demonstrates the clinical and radiographic correlation between percutaneous drainage of infected intraabdominal collections and the development of iatrogenic pleural space infections. A retrospective single institution analysis of 550 consecutive percutaneous drainage procedures for intraabdominal fluid collections was performed over 24 months. Patient charts and imaging were reviewed with regard to pleural space infections that were attributed to percutaneous drain placements. Institutional review board approval was obtained for conduct of the study. 6/550 (1.1%) patients developed iatrogenic pleural space infections after percutaneous drainage of intraabdominal fluid collections. All 6 patients presented with respiratory symptoms and required pleural space drainage (either by needle aspiration or chest tube placement), 2 received intrapleural fibrinolytic therapy and 1 patient had to undergo surgical drainage. Pleural effusion cultures revealed same bacteria in both intraabdominal and pleural fluid in 3 (50%) cases. A video with a dynamic radiographic sequence demonstrating the contamination of the pleural space from percutaneous drainage of an infected intraabdominal collection is included. Iatrogenic pleural space infections after percutaneous drainage of intraabdominal fluid collections occur at a low incidence, but the pleural empyema can be progressive requiring prompt chest tube drainage, intrapleural fibrinolytic therapy or even surgery. Expertise in intraabdominal drain placements, awareness and early recognition of this complication is critical to minimize incidence, morbidity and mortality in these patients.

  1. Static Analysis of High-Performance Fixed Fluid Power Drive with a Single Positive-Displacement Hydraulic Motor

    Directory of Open Access Journals (Sweden)

    O. F. Nikitin

    2015-01-01

    Full Text Available The article deals with the static calculations in designing a high-performance fixed fluid power drive with a single positive-displacement hydraulic motor. Designing is aimed at using a drive that is under development and yet unavailable to find and record the minimum of calculations and maximum of existing hydraulic units that enable clear and unambiguous performance, taking into consideration an available assortment of hydraulic units of hydraulic drives, to have the best efficiency.The specified power (power, moment and kinematics (linear velocity or angular velocity of rotation parameters of the output element of hydraulic motor determine the main output parameters of the hydraulic drive and the useful power of the hydraulic drive under development. The value of the overall efficiency of the hydraulic drive enables us to judge the efficiency of high-performance fixed fluid power drive.The energy analysis of a diagram of the high-performance fixed fluid power drive shows that its high efficiency is achieved when the flow rate of fluid flowing into each cylinder and the magnitude of the feed pump unit (pump are as nearly as possible.The paper considers the ways of determining the geometric parameters of working hydromotors (effective working area or working volume, which allow a selection of the pumping unit parameters. It discusses the ways to improve hydraulic drive efficiency. Using the principle of holding constant conductivity allows us to specify the values of the pressure losses in the hydraulic units used in noncatalog modes. In case of no exact matching between the parameters of existing hydraulic power modes and a proposed characteristics of the pump unit, the nearest to the expected characteristics is taken as a working version.All of the steps allow us to create the high-performance fixed fluid power drive capable of operating at the required power and kinematic parameters with high efficiency.

  2. System and method for single-phase, single-stage grid-interactive inverter

    Science.gov (United States)

    Liu, Liming; Li, Hui

    2015-09-01

    The present invention provides for the integration of distributed renewable energy sources/storages utilizing a cascaded DC-AC inverter, thereby eliminating the need for a DC-DC converter. The ability to segment the energy sources and energy storages improves the maintenance capability and system reliability of the distributed generation system, as well as achieve wide range reactive power compensation. In the absence of a DC-DC converter, single stage energy conversion can be achieved to enhance energy conversion efficiency.

  3. Thermodynamics of Fluid Polyamorphism

    Directory of Open Access Journals (Sweden)

    Mikhail A. Anisimov

    2018-01-01

    Full Text Available Fluid polyamorphism is the existence of different condensed amorphous states in a single-component fluid. It is either found or predicted, usually at extreme conditions, for a broad group of very different substances, including helium, carbon, silicon, phosphorous, sulfur, tellurium, cerium, hydrogen, and tin tetraiodide. This phenomenon is also hypothesized for metastable and deeply supercooled water, presumably located a few degrees below the experimental limit of homogeneous ice formation. We present a generic phenomenological approach to describe polyamorphism in a single-component fluid, which is completely independent of the molecular origin of the phenomenon. We show that fluid polyamorphism may occur either in the presence or in the absence of fluid phase separation depending on the symmetry of the order parameter. In the latter case, it is associated with a second-order transition, such as in liquid helium or liquid sulfur. To specify the phenomenology, we consider a fluid with thermodynamic equilibrium between two distinct interconvertible states or molecular structures. A fundamental signature of this concept is the identification of the equilibrium fraction of molecules involved in each of these alternative states. However, the existence of the alternative structures may result in polyamorphic fluid phase separation only if mixing of these structures is not ideal. The two-state thermodynamics unifies all the debated scenarios of fluid polyamorphism in different areas of condensed-matter physics, with or without phase separation, and even goes beyond the phenomenon of polyamorphism by generically describing the anomalous properties of fluids exhibiting interconversion of alternative molecular states.

  4. Single-phase and two-phase gas-liquid turbulent mixing between subchannels in a simulated rod bundle

    International Nuclear Information System (INIS)

    Sadatomi, Michio; Kawahara, Akimaro; Sato, Yoshifusa; Tomino, Takayoshi.

    1996-01-01

    This study is concerned with turbulent mixing which is one of the three mechanisms of cross flows between subchannels in a nuclear fuel rod bundle. The channel used in this experiments was a vertical simulated rod bundle having two subchannels connected through 1 to 3 gaps between two rods and/or rod and channel wall. The number of the gaps was changed to investigate the effect of the number on the turbulent mixing. Turbulent mixing rates of air and water and fluctuations of pressure difference between the subchannels were measured for single-phase and two-phase gas-liquid flows under hydrodynamic equilibrium flow conditions. It has been confirmed that the turbulent mixing rate is affected strongly by the fluctuations especially for liquid phase in two-phase slug or churn flow. (author)

  5. Critical velocities in fluid-conveying single-walled carbon nanotubes embedded in an elastic foundation

    Science.gov (United States)

    Rao, Ch. K.; Rao, L. B.

    2017-07-01

    The problem of stability of fluid-conveying carbon nanotubes embedded in an elastic medium is investigated in this paper. A nonlocal continuum mechanics formulation, which takes the small length scale effects into consideration, is utilized to derive the governing fourth-order partial differential equations. The Fourier series method is used for the case of the pinned-pinned boundary condition of the tube. The Galerkin technique is utilized to find a solution of the governing equation for the case of the clamped-clamped boundary. Closed-form expressions for the critical flow velocity are obtained for different values of the Winkler and Pasternak foundation stiffness parameters. Moreover, new and interesting results are also reported for varying values of the nonlocal length parameter. It is observed that the nonlocal length parameter along with the Winkler and Pasternak foundation stiffness parameters exert considerable effects on the critical velocities of the fluid flow in nanotubes.

  6. Characterization and optimization of single-use bioreactors and biopharmaceutical production processes using computational fluid dynamics

    OpenAIRE

    Kaiser, Stephan Christian

    2015-01-01

    Durch die örtliche und zeitliche Modellierung der auftretenden Strömungen bietet die numerische Fluiddynamik (engl. Computational Fluid Dynamics, CFD) das Potenzial detaillierte Untersuchungen der Hydrodynamik in Bioreaktoren durchzuführen. Allerdings sind bisher nur wenige Studien in Verbindung mit Einwegbioreaktoren, die sich durch konstruktiven Besonderheiten von ihren klassischen Gegenspielern aus Glas und/oder Edelstahl unterscheiden, publiziert. Die vorliegende Arbeit soll daher geeigne...

  7. Analytical predictions for vibration phase shifts along fluid-conveying pipes due to Coriolis forces and imperfections

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Dahl, Jonas

    2010-01-01

    -shift measuring devices such as Coriolis mass flowmeters in particular. Small imperfections related to elastic and dissipative support conditions are specifically addressed, but the suggested approach is readily applicable to other kinds of imperfection, e.g. non-uniform stiffness or mass, non......-proportional damping, weak nonlinearity, and flow pulsation. A multiple time scaling perturbation analysis is employed for a simple model of an imperfect fluid-conveying pipe. This leads to simple analytical expressions for the approximate prediction of phase shift, providing direct insight into which imperfections...... the symmetric part of damping as well as non-uniformity in mass or stiffness do not affect phase shift. The validity of such hypotheses can be tested using detailed fluid-structure interaction computer models or laboratory experiments....

  8. Criterion for traffic phases in single vehicle data and empirical test of a microscopic three-phase traffic theory

    International Nuclear Information System (INIS)

    Kerner, Boris S; Klenov, Sergey L; Hiller, Andreas

    2006-01-01

    Based on empirical and numerical microscopic analyses, the physical nature of a qualitatively different behaviour of the wide moving jam phase in comparison with the synchronized flow phase-microscopic traffic flow interruption within the wide moving jam phase-is found. A microscopic criterion for distinguishing the synchronized flow and wide moving jam phases in single vehicle data measured at a single freeway location is presented. Based on this criterion, empirical microscopic classification of different local congested traffic states is performed. Simulations made show that the microscopic criterion and macroscopic spatiotemporal objective criteria lead to the same identification of the synchronized flow and wide moving jam phases in congested traffic. Microscopic models in the context of three-phase traffic theory have been tested based on the microscopic criterion for the phases in congested traffic. It is found that microscopic three-phase traffic models can explain both microscopic and macroscopic empirical congested pattern features. It is obtained that microscopic frequency distributions for vehicle speed difference as well as fundamental diagrams and speed correlation functions can depend on the spatial co-ordinate considerably. It turns out that microscopic optimal velocity (OV) functions and time headway distributions are not necessarily qualitatively different, even if local congested traffic states are qualitatively different. The reason for this is that important spatiotemporal features of congested traffic patterns are lost in these as well as in many other macroscopic and microscopic traffic characteristics, which are widely used as the empirical basis for a test of traffic flow models, specifically, cellular automata traffic flow models

  9. Numerical modeling of two-phase binary fluid mixing using mixed finite elements

    KAUST Repository

    Sun, Shuyu; Firoozabadi, Abbas; Kou, Jisheng

    2012-01-01

    -phase flow in porous media is established based on Darcy's law, material balance, local thermodynamic equilibrium for the phases, and diffusion across the phases. The time-lag and operator-splitting techniques are used to decompose each convection

  10. Single particle analysis based on Zernike phase contrast transmission electron microscopy.

    Science.gov (United States)

    Danev, Radostin; Nagayama, Kuniaki

    2008-02-01

    We present the first application of Zernike phase-contrast transmission electron microscopy to single-particle 3D reconstruction of a protein, using GroEL chaperonin as the test specimen. We evaluated the performance of the technique by comparing 3D models derived from Zernike phase contrast imaging, with models from conventional underfocus phase contrast imaging. The same resolution, about 12A, was achieved by both imaging methods. The reconstruction based on Zernike phase contrast data required about 30% fewer particles. The advantages and prospects of each technique are discussed.

  11. Effect of wortmannin and phorbol ester on Paramecium fluid-phase uptake in the presence of transferrin

    Directory of Open Access Journals (Sweden)

    J Wiejak

    2009-12-01

    Full Text Available The kinetics of the uptake of the fluid phase marker Lucifer Yellow (LY, and its alteration by wortmannin, an inhibitor of phosphatidylinositol-3 kinase (PI-3K, and the PKC modulators: GF 109203 X, an inhibitor, and phorbol ester, an activator was studied in eukaryotic model Paramecium aurelia. Spectrophotometric quantification of LY accumulation was performed in the presence or absence of transferrin, a marker of receptor-mediated endocytosis. Internalization of LY showed a curvilinear kinetics: the high initial rate of LYuptake (575 ng LY/ mg protein /hr decreased almost 5-fold within 15 min, reaching plateau at 126 ng/ mg protein /hr. Transferrin induced a small increase (7.5% in the fluid phase uptake rate (after 5 min followed by a small decrease at longer incubation times. Lucifer Yellow and transferrin (visualized by streptavidin– FITC were localized in Paramecium by 3-D reconstruction by confocal microscopy. LY showed a scattered, diffuse fluorescence typical of fluid phase uptake whereas transferrin accumulated in membrane-surrounded endosomes. Wortmannin did not affect LY accumulation but decreased it when transferrin was present in the incubation medium. This suggests an effect on the transferrin uptake pathway, presumably on the stage of internalization in “mixing” endosomes to which transferrin and LY were targeted. Phorbol ester diminished LY accumulation by 22% and this effect persisted up to 25 min of incubation. PKC inhibitor did not affect LY uptake. However, in the presence of transferrin, the LY uptake increased within the first 15 minutes followed by a rapid 20% decrease in comparison to the control. Such an effect of PKC modulators suggests that PMA action on fluid phase uptake is not directly mediated by PKC.

  12. Investigating the Relationship between Cerebrospinal Fluid and Magnetic Induction Phase Shift in Rabbit Intracerebral hematoma expansion Monitoring by MRI

    OpenAIRE

    Chen, Mingsheng; Yan, Qingguang; Sun, Jian; Jin, Gui; Qin, Mingxin

    2017-01-01

    In a prior study of intracerebral hemorrhage monitoring using magnetic induction phase shift (MIPS), we found that MIPS signal changes occurred prior to those seen with intracranial pressure. However, the characteristic MIPS alert is not yet fully explained. Combining the brain physiology and MIPS theory, we propose that cerebrospinal fluid (CSF) may be the primary factor that leads to hematoma expansion being alerted by MIPS earlier than with intracranial pressure monitoring. This paper inve...

  13. Single-phase ProtoDUNE, the Prototype of a Single-Phase Liquid Argon TPC for DUNE at the CERN Neutrino Platform

    CERN Document Server

    Cavanna, F; Touramanis, C

    2017-01-01

    ProtoDUNE-SP is the single-phase DUNE Far Detector prototype that is under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018. It was proposed to the CERN SPSC in June 2015 (SPSC-P-351) and was approved in December 2015 as experiment NP04 (ProtoDUNE). ProtoDUNE-SP, a crucial part of the DUNE effort towards the construction of the first DUNE 10-kt fiducial mass far detector module (17 kt total LAr mass), is a significant experiment in its own right. With a total liquid argon (LAr) mass of 0.77 kt, it represents the largest monolithic single phase LArTPC detector to be built to date. It is housed in an extension to the EHN1 hall in the North Area, where the CERN NP is providing a new dedicated charged-particle test beamline. ProtoDUNE-SP aims to take its first beam data before the LHC long shutdown (LS2) at the end of 2018. ProtoDUNE-SP prototypes the designs of most of the single-phase DUNE far detector module (DUNE-SP) components at a 1:1 scale, with an extrapolation of abo...

  14. A review of modern advances in analyses and applications of single-phase natural circulation loop in nuclear thermal hydraulics

    International Nuclear Information System (INIS)

    Basu, Dipankar N.; Bhattacharyya, Souvik; Das, P.K.

    2014-01-01

    Highlights: • Comprehensive review of state-of-the-art on single-phase natural circulation loops. • Detailed discussion on growth in solar thermal system and nuclear thermal hydraulics. • Systematic development in scaling methodologies for fabrication of test facilities. • Importance of numerical modeling schemes for stability assessment using 1-D codes. • Appraisal of current trend of research and possible future directions. - Abstract: A comprehensive review of single-phase natural circulation loop (NCL) is presented here. Relevant literature reported since the later part of 1980s has been meticulously surveyed, with occasional obligatory reference to a few pioneering studies originating prior to that period, summarizing the key observations and the present trend of research. Development in the concept of buoyancy-induced flow is discussed, with introduction to flow initiation in an NCL due to instability. Detailed discussion on modern advancement in important application areas like solar thermal systems and nuclear thermal hydraulics are presented, with separate analysis for various reactor designs working on natural circulation. Identification of scaling criteria for designing lab-scale experimental facilities has gone through a series of modification. A systematic analysis of the same is presented, considering the state-of-the-art knowledge base. Different approaches have been followed for modeling single-phase NCLs, including simplified Lorenz system mostly for toroidal loops, 1-D computational modeling for both steady-state and stability characterization and 3-D commercial system codes to have a better flow visualization. Methodical review of the relevant studies is presented following a systematic approach, to assess the gradual progression in understanding of the practical system. Brief appraisal of current research interest is reported, including the use of nanofluids for fluid property augmentation, marine reactors subjected to rolling waves

  15. A review of modern advances in analyses and applications of single-phase natural circulation loop in nuclear thermal hydraulics

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Dipankar N., E-mail: dipankar.n.basu@gmail.com [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati 781039 (India); Bhattacharyya, Souvik; Das, P.K. [Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302 (India)

    2014-12-15

    Highlights: • Comprehensive review of state-of-the-art on single-phase natural circulation loops. • Detailed discussion on growth in solar thermal system and nuclear thermal hydraulics. • Systematic development in scaling methodologies for fabrication of test facilities. • Importance of numerical modeling schemes for stability assessment using 1-D codes. • Appraisal of current trend of research and possible future directions. - Abstract: A comprehensive review of single-phase natural circulation loop (NCL) is presented here. Relevant literature reported since the later part of 1980s has been meticulously surveyed, with occasional obligatory reference to a few pioneering studies originating prior to that period, summarizing the key observations and the present trend of research. Development in the concept of buoyancy-induced flow is discussed, with introduction to flow initiation in an NCL due to instability. Detailed discussion on modern advancement in important application areas like solar thermal systems and nuclear thermal hydraulics are presented, with separate analysis for various reactor designs working on natural circulation. Identification of scaling criteria for designing lab-scale experimental facilities has gone through a series of modification. A systematic analysis of the same is presented, considering the state-of-the-art knowledge base. Different approaches have been followed for modeling single-phase NCLs, including simplified Lorenz system mostly for toroidal loops, 1-D computational modeling for both steady-state and stability characterization and 3-D commercial system codes to have a better flow visualization. Methodical review of the relevant studies is presented following a systematic approach, to assess the gradual progression in understanding of the practical system. Brief appraisal of current research interest is reported, including the use of nanofluids for fluid property augmentation, marine reactors subjected to rolling waves

  16. Plutonium (TRU) transmutation and {sup 233}U production by single-fluid type accelerator molten-salt breeder (AMSB)

    Energy Technology Data Exchange (ETDEWEB)

    Furukaw, Kazuo [Tokai Univ., Kanagawa (Japan); Kato, Yoshio [Japan Atom. Ene. Res. Inst., Ibaraki (Japan); Chigrinov, Sergey E. [Academy of Science, Minsk (Belarus)

    1995-10-01

    For practical/industrial disposition of Pu(TRU) by accelerator facility, not only physical soundness and safety but also the following technological rationality should be required: (1) few R&D items including radiation damage, heat removal and material compatibility; (2) few operation/maintenance/processing works: (3) few reproduction of radioactivity; (4) effective energy production in parallel. This will be achieved by the new modification of Th-fertilizing Single-Fluid type Accelerator Molten-Salt Breeder (AMSB), by which a global nuclear energy strategy for next century might be prepared.

  17. The complete information for phenomenal distributed parameter control of multicomponent chemical processes in gas, fluid and solid phase

    International Nuclear Information System (INIS)

    Niemiec, W.

    1985-01-01

    A constitutive mathematical model of distributed parameters of multicomponent chemical processes in gas, fluid and solid phase is utilized to the realization of phenomenal distributed parameter control of these processes. Original systems of partial differential constitutive state equations, in the following derivative forms /I/, /II/ and /III/ are solved in this paper from the point of view of information for phenomenal distributed parameter control of considered processes. Obtained in this way for multicomponent chemical processes in gas, fluid and solid phase: -dynamical working space-time characteristics/analytical solutions in working space-time of chemical reactors/, -dynamical phenomenal Green functions as working space-time transfer functions, -statical working space characteristics /analytical solutions in working space of chemical reactors/, -statical phenomenal Green functions as working space transfer functions, are applied, as information for realization of constitutive distributed parameter control of mass, energy and momentum aspects of above processes. Two cases are considered by existence of: A/sup o/ - initial conditions, B/sup o/ - initial and boundary conditions, for multicomponent chemical processes in gas, fluid and solid phase

  18. Dynamics of snap-off and pore-filling events during two-phase fluid flow in permeable media.

    Science.gov (United States)

    Singh, Kamaljit; Menke, Hannah; Andrew, Matthew; Lin, Qingyang; Rau, Christoph; Blunt, Martin J; Bijeljic, Branko

    2017-07-12

    Understanding the pore-scale dynamics of two-phase fluid flow in permeable media is important in many processes such as water infiltration in soils, oil recovery, and geo-sequestration of CO 2 . The two most important processes that compete during the displacement of a non-wetting fluid by a wetting fluid are pore-filling or piston-like displacement and snap-off; this latter process can lead to trapping of the non-wetting phase. We present a three-dimensional dynamic visualization study using fast synchrotron X-ray micro-tomography to provide new insights into these processes by conducting a time-resolved pore-by-pore analysis of the local curvature and capillary pressure. We show that the time-scales of interface movement and brine layer swelling leading to snap-off are several minutes, orders of magnitude slower than observed for Haines jumps in drainage. The local capillary pressure increases rapidly after snap-off as the trapped phase finds a position that is a new local energy minimum. However, the pressure change is less dramatic than that observed during drainage. We also show that the brine-oil interface jumps from pore-to-pore during imbibition at an approximately constant local capillary pressure, with an event size of the order of an average pore size, again much smaller than the large bursts seen during drainage.

  19. Flow rate impacts on capillary pressure and interface curvature of connected and disconnected fluid phases during multiphase flow in sandstone

    Science.gov (United States)

    Herring, Anna L.; Middleton, Jill; Walsh, Rick; Kingston, Andrew; Sheppard, Adrian

    2017-09-01

    We investigate capillary pressure-saturation (PC-S) relationships for drainage-imbibition experiments conducted with air (nonwetting phase) and brine (wetting phase) in Bentheimer sandstone cores. Three different flow rate conditions, ranging over three orders of magnitude, are investigated. X-ray micro-computed tomographic imaging is used to characterize the distribution and amount of fluids and their interfacial characteristics. Capillary pressure is measured via (1) bulk-phase pressure transducer measurements, and (2) image-based curvature measurements, calculated using a novel 3D curvature algorithm. We distinguish between connected (percolating) and disconnected air clusters: curvatures measured on the connected phase interfaces are used to validate the curvature algorithm and provide an indication of the equilibrium condition of the data; curvature and volume distributions of disconnected clusters provide insight to the snap-off processes occurring during drainage and imbibition under different flow rate conditions.

  20. Some new possibilities for the diagnostics of single-phase and two-phase plasma jets

    Energy Technology Data Exchange (ETDEWEB)

    Goldfarb, V M

    1979-02-01

    The literature on three classes of methods for the diagnostics of plasma jets is reviewed. These classes include nonintrusive measurements (spectroscopy, refractometry, scatterometry, and plasma velocimetry) intrusive measurements (electrostatic probes and calorimeters) and measurements of solid-phase properties (pyrometry, particle track records, diffractometry, light attenuation measurements, and laser Doppler velocimeters).

  1. Tunable phase transition in single-layer TiSe2 via electric field

    Science.gov (United States)

    Liu, Lei; Zhuang, Houlong L.

    2018-06-01

    Phase transition represents an intriguing physical phenomenon that exists in a number of single-layer transition-metal dichalcogenides. This phenomenon often occurs below a critical temperature and breaks the long-range crystalline order leading to a reconstructed superstructure called the charge-density wave (CDW) structure, which can therefore be recovered by external stimuli such as temperature. Alternatively, we show here that another external stimulation, electric field can also result in the phase transition between the regular and CDW structures of a single-layer transition-metal dichalcogenide. We used single-layer TiSe2 as an example to elucidate the mechanism of the CDW followed by calculations of the electronic structure using a hybrid density functional. We found that applying electric field can tune the phase transition between the 1T and CDW phases of single-layer TiSe2. Our work opens up a route of tuning the phase transition of single-layer materials via electric field.

  2. A Simple and Consistent Equation of State for Sodium in the Single Phase and Two Phase Regions

    International Nuclear Information System (INIS)

    Breton, J.P.

    1976-01-01

    An equation of state valid over an extended temperature and density range has been derived. Then, the following properties have been deduced: coefficient of thermal expansion, isothermal coefficient of bulk compressibility, thermal pressure coefficient, heat capacity at constant pressure, at constant volume, along the saturation curve for liquid, for vapor, heat of vaporization, speed of sound, and finally the Mollier diagram and the entropy diagram. All the obtained properties are thermodynamically consistent and satisfy the basic relations of thermodynamics for both single phase and two-phase regions. Experimental results were always used when available

  3. A simple and consistent equation of state for sodium in the single phase and two phase regions

    International Nuclear Information System (INIS)

    Breton, J.P.

    1976-01-01

    An equation of state valid over an extended temperature and density range has been derived. Then, the following properties have been deduced : coefficient of thermal expansion, isothermal coefficient of bulk compressibility, thermal pressure coefficient, heat capacity at constant pressure, at constant volume, along the saturation curve for liquid, for vapor, heat of vaporization, speed of sound, and finally the Mollier diagram and the entropy diagram. All the obtained properties are thermodynamically consistent and satisfy the basic relations of thermodynamics for both single phase and two-phase regions. Experimental results were always used when available. (auth.)

  4. Variation in supratentorial cerebrospinal fluid production rate in one day. Measurement by nontriggered phase-contrast magnetic resonance imaging

    International Nuclear Information System (INIS)

    Takahashi, Hiroto; Tanaka, Hisashi; Fujita, Norihiko; Murase, Kenya; Tomiyama, Noriyuki

    2011-01-01

    Measuring the cerebrospinal fluid (CSF) production rate is important for understanding the physiology related to normal conditions and neurological disorders. Triggered phase-contrast magnetic resonance imaging (MRI) has been used to measure CSF production rate, but the use of nontriggered phase-contrast MRI has not been reported. The purposes of this study were to assess the feasibility of using nontriggered phase-contrast MRI to measure CSF flow and to determine whether CSF production exhibits circadian rhythm. The feasibility of phase-contrast MRI was assessed with a phantom simulated human cerebral aqueduct. CSF flow through the cerebral aqueduct was measured with nontriggered phase-contrast MRI four times during 1 day in 10 normal volunteers. In the phantom study, linear regression analysis gave the following measured values (ml/h): 0.80 x (value of steady flow)-10.0 for triggered phase-contrast MRI and 1.27 x (value of steady flow)-12.2 for nontriggered phase-contrast MRI. One-factor analysis of variance showed no significant effect of the time of the measurements (P=0.47). The supratentorial CSF production rate was 510±549 ml/day (mean ± SD). Nontriggered phase-contrast MRI provided good estimates of the flow rate in the phantom study. We observed no circadian rhythm in CSF production. (author)

  5. A single photon emission computed tomograph based on a limited dumber of detectors for fluid flow visualization

    International Nuclear Information System (INIS)

    Legoupil, S.

    1999-01-01

    We present in this work a method for fluid flow visualization in a system using radioactive tracers. The method is based on single photon emission computed tomography techniques, applied to a limited number of discrete detectors. We propose in this work a method for the estimation of the transport matrix of photons, associated to the acquisition system. This method is based on the modelization of profiles acquired for a set of point sources located in the imaged volume. Monte Carlo simulations allow to separate scattered photons from those directly collected by the system. The influence of the energy tracer is exposed. The reconstruction method is based on the maximum likelihood - expectation maximization algorithm. An experimental device, based on 36 detectors was realised for the visualization of water circulation in a vessel. A video monitoring allows to visualize the dye water tracer. Dye and radioactive tracers are injected simultaneously in a water flow circulating in the vessel. Reconstructed and video images are compared. Quantitative and qualitative analysis show that fluid flow visualization is feasible with a limited number of detectors. This method can be applied for system involving circulations of fluids. (author)

  6. Integrated Reacting Fluid Dynamics and Predictive Materials Degradation Models for Propulsion System Conditions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Computational fluid dynamics (CFD) simulations are routinely used by NASA to optimize the design of propulsion systems. Current methods for CFD modeling rely on...

  7. Effectiveness of Nitrous Oxide as a Liquid Injection Thrust Vector Control Fluid, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Nitrous Oxide is proposed as an energetic liquid injection thrust vector control fluid for vehicle attitude control during dynamic vehicle maneuvers. Pulled from the...

  8. Subchannel Scale Thermal-Hydraulic Analysis of Rod Bundle Geometry under Single-phase Adiabatic Conditions Using CUPID

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Seok Jong; Park, Goon Cherl; Cho, Hyoung Kyu [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In Korea, subchannel analysis code, MATRA has been developed by KAERI (Korea Atomic Energy Research Institute). MATRA has been used for reactor core T/H design and DNBR (Departure from Nucleate Boiling Ratio) calculation. Also, the code has been successfully coupled with neutronics code and fuel analysis code. However, since major concern of the code is not the accident simulation, some features of the code are not optimized for the accident conditions, such as the homogeneous model for two-phase flow and spatial marching method for numerical scheme. For this reason, in the present study, application of CUPID for the subchannel scale T/H analysis in rod bundle geometry was conducted. CUPID is a component scale T/H analysis code which adopts three dimensional two-fluid three-field model developed by KAERI. In this paper, the validation results of the CUPID code for subchannel scale rod bundle analysis at single phase adiabatic conditions were presented. At first, the physical models required for a subchannel scale analysis were implemented to CUPID. In the future, the scope of validation tests will be extended to diabetic and two phase flow conditions and required models will be implemented into CUPID.

  9. Experimental Comparison Of Working Fluids For Organic Rankine Cycle With Single-Screw Expander

    OpenAIRE

    Gusev, Sergei; Ziviani, Davide; Bell, Ian; De Paepe, Michel; van den Broek, Martijn

    2014-01-01

    This paper describes the behavior of an Organic Rankine Cycle (ORC) fed by a heat source with adaptable temperature and mass flow. For a suitable choice of working fluid, the setting of its evaporation pressure is crucial for the performance of an ORC installation. The higher the evaporation pressure, the higher the cycle efficiency on the one hand, but the lower the energy recovered from the heat source due to a higher outlet temperature on the other hand. An optimum has to be found to achie...

  10. Plasma-treated carbonyl iron particles as a dispersed phase in magnetorheological fluids

    Czech Academy of Sciences Publication Activity Database

    Sedlačík, M.; Pavlínek, V.; Lehocký, M.; Mráček, A.; Grulich, O.; Švrčinová, Petra; Filip, Petr; Vesel, A.

    2011-01-01

    Roč. 387, 1-3 (2011), s. 99-103 ISSN 0927-7757 Grant - others:GA ČR(CZ) GD104/09/H080; OP VaVpI(XE) CZ.1.05/2.1.00/03.0111 Program:GD Institutional research plan: CEZ:AV0Z20600510 Keywords : carbonyl iron * magnetorheological fluid * plasma * viscoelasticity Subject RIV: BK - Fluid Dynamics Impact factor: 2.236, year: 2011

  11. Phase-and-amplitude recovery from a single phase-contrast image using partially spatially coherent x-ray radiation

    Science.gov (United States)

    Beltran, Mario A.; Paganin, David M.; Pelliccia, Daniele

    2018-05-01

    A simple method of phase-and-amplitude extraction is derived that corrects for image blurring induced by partially spatially coherent incident illumination using only a single intensity image as input. The method is based on Fresnel diffraction theory for the case of high Fresnel number, merged with the space-frequency description formalism used to quantify partially coherent fields and assumes the object under study is composed of a single-material. A priori knowledge of the object’s complex refractive index and information obtained by characterizing the spatial coherence of the source is required. The algorithm was applied to propagation-based phase-contrast data measured with a laboratory-based micro-focus x-ray source. The blurring due to the finite spatial extent of the source is embedded within the algorithm as a simple correction term to the so-called Paganin algorithm and is also numerically stable in the presence of noise.

  12. Reliability Evaluation of a Single-phase H-bridge Inverter with Integrated Active Power Decoupling

    DEFF Research Database (Denmark)

    Tang, Junchaojie; Wang, Haoran; Ma, Siyuan

    2016-01-01

    it with the traditional passive DC-link solution. The converter level reliability is obtained by component level electro-thermal stress modeling, lifetime model, Weibull distribution, and Reliability Block Diagram (RBD) method. The results are demonstrated by a 2 kW single-phase inverter application.......Various power decoupling methods have been proposed recently to replace the DC-link Electrolytic Capacitors (E-caps) in single-phase conversion system, in order to extend the lifetime and improve the reliability of the DC-link. However, it is still an open question whether the converter level...... reliability becomes better or not, since additional components are introduced and the loading of the existing components may be changed. This paper aims to study the converter level reliability of a single-phase full-bridge inverter with two kinds of active power decoupling module and to compare...

  13. High Quality Model Predictive Control for Single Phase Grid Connected Photovoltaic Inverters

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2018-01-01

    Single phase grid-connected inverters with LCL filter are widely used to connect the photovoltaic systems to the utility grid. Among the presented control schemes, predictive control methods are faster and more accurate but are more complex to implement. Recently, the model-predictive control...... algorithm for single-phase inverter has been presented, where the algorithm implementation is straightforward. In the proposed approach, all switching states are tested in each switching period to achieve the control objectives. However, since the number of the switching states in single-phase inverter...... is low, the inverter output current has a high total harmonic distortions. In order to reduce the total harmonic distortions of the injected current, this paper presents a high-quality model-predictive control for one of the newest structure of the grid connected photovoltaic inverter, i.e., HERIC...

  14. Hydrodynamic prediction of multidimensional single- and two-phase flow in rod arrays. Progress report, January 1-December 31, 1983

    International Nuclear Information System (INIS)

    Ebeling-Koning, D.B.; Robinson, J.T.; Todreas, N.E.

    1984-01-01

    The objective of this research is to develop comprehensive constitutive models for multidimensional two-phase flow in rod arrays. The constitutive parameters are the solid-fluid flow resistance and the gas-liquid interfacial momentum exchange force. This report covers work in four areas: (1) a correlation for flow resistance across banks of tubes which is independent of rod arrangement has been developed. The correlation was developed from data from three rod arrangements covering a Reynolds number range (based on superficial velocity) of 1 to 40,000; (2) complete pressure drop data for water flows in the laminar region in crossflow and 45 0 inclined rod arrays were taken; (3) the development of a model for the interfacial momentum exchange force in bubbly flows has been completed. This model has been validated against single bubble velocity data in inclined rod arrays. The model has been cast in a form suitable for implementation to two-fluid computer codes; and (4) rise velocities of bubbles in 0 0 , 45 0 , and 90 0 inclined rod arrays have been measured. This data should prove useful for the development of a bubble drag coefficient model for rod arrays

  15. Single-phase liquid flow forced convection under a nearly uniform heat flux boundary condition in microchannels

    KAUST Repository

    Lee, Man; Lee, Yi-Kuen; Zohar, Yitshak

    2012-01-01

    A microchannel heat sink, integrated with pressure and temperature microsensors, is utilized to study single-phase liquid flow forced convection under a uniform heat flux boundary condition. Utilizing a waferbond-and-etch- back technology, the heat source, temperature and pressure sensors are encapsulated in a thin composite membrane capping the microchannels, thus allowing experimentally good control of the thermal boundary conditions. A three-dimensional physical model has been constructed to facilitate numerical simulations of the heat flux distribution. The results indicate that upstream the cold working fluid absorbs heat, while, within the current operating conditions, downstream the warmer working fluid releases heat. The Nusselt number is computed numerically and compared with experimental and analytical results. The wall Nusselt number in a microchannel can be estimated using classical analytical solutions only over a limited range of the Reynolds number, Re: both the top and bottom Nusselt numbers approach 4 for Re < 1, while the top and bottom Nusselt numbers approach 0 and 5.3, respectively, for Re > 100. The experimentally estimated Nusselt number for forced convection is highly sensitive to the location of the temperature measurements used in calculating the Nusselt number. © 2012 IOP Publishing Ltd.

  16. Single-phase liquid flow forced convection under a nearly uniform heat flux boundary condition in microchannels

    KAUST Repository

    Lee, Man

    2012-02-22

    A microchannel heat sink, integrated with pressure and temperature microsensors, is utilized to study single-phase liquid flow forced convection under a uniform heat flux boundary condition. Utilizing a waferbond-and-etch- back technology, the heat source, temperature and pressure sensors are encapsulated in a thin composite membrane capping the microchannels, thus allowing experimentally good control of the thermal boundary conditions. A three-dimensional physical model has been constructed to facilitate numerical simulations of the heat flux distribution. The results indicate that upstream the cold working fluid absorbs heat, while, within the current operating conditions, downstream the warmer working fluid releases heat. The Nusselt number is computed numerically and compared with experimental and analytical results. The wall Nusselt number in a microchannel can be estimated using classical analytical solutions only over a limited range of the Reynolds number, Re: both the top and bottom Nusselt numbers approach 4 for Re < 1, while the top and bottom Nusselt numbers approach 0 and 5.3, respectively, for Re > 100. The experimentally estimated Nusselt number for forced convection is highly sensitive to the location of the temperature measurements used in calculating the Nusselt number. © 2012 IOP Publishing Ltd.

  17. Phase retrieval from a single fringe pattern by using empirical wavelet transform

    International Nuclear Information System (INIS)

    Guo, Xiaopeng; Zhao, Hong; Wang, Xin

    2015-01-01

    Phase retrieval from a single fringe pattern is one of the key tasks in optical metrology. In this paper, we present a new method for phase retrieval from a single fringe pattern based on empirical wavelet transform. In the proposed method, a fringe pattern can be effectively divided into three components: nonuniform background, fringes and random noise, which are described in different sub-pass. So the phase distribution information can be robustly extracted from fringes representing a fundamental frequency component. In simulation and a practical projection fringes test, the performance of the present method is successfully verified by comparing with the conventional wavelet transform method in terms of both image quality and phase estimation errors. (paper)

  18. Algorithms for image recovery calculation in extended single-shot phase-shifting digital holography

    Science.gov (United States)

    Hasegawa, Shin-ya; Hirata, Ryo

    2018-04-01

    The single-shot phase-shifting method of image recovery using an inclined reference wave has the advantages of reducing the effects of vibration, being capable of operating in real time, and affording low-cost sensing. In this method, relatively low reference angles compared with that in the conventional method using phase shift between three or four pixels has been required. We propose an extended single-shot phase-shifting technique which uses the multiple-step phase-shifting algorithm and the corresponding multiple pixels which are the same as that of the period of an interference fringe. We have verified the theory underlying this recovery method by means of Fourier spectral analysis and its effectiveness by evaluating the visibility of the image using a high-resolution pattern. Finally, we have demonstrated high-contrast image recovery experimentally using a resolution chart. This method can be used in a variety of applications such as color holographic interferometry.

  19. Single-phase dual-energy CT urography in the evaluation of haematuria.

    Science.gov (United States)

    Ascenti, G; Mileto, A; Gaeta, M; Blandino, A; Mazziotti, S; Scribano, E

    2013-02-01

    To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic-excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic-excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Single-phase DECT urography with synchronous nephrographic-excretory phase enhancement represents an accurate "all-in-one'' approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol. Copyright © 2012 The Royal College of Radiologists. All rights reserved.

  20. Single-phase dual-energy CT urography in the evaluation of haematuria

    International Nuclear Information System (INIS)

    Ascenti, G.; Mileto, A.; Gaeta, M.; Blandino, A.; Mazziotti, S.; Scribano, E.

    2013-01-01

    Aim: To assess the value of a single-phase dual-energy computed tomography (DECT) urography protocol with synchronous nephrographic–excretory phase enhancement and to calculate the potential dose reduction by omitting the unenhanced scan. Materials and methods: Eighty-four patients referred for haematuria underwent CT urography using a protocol that included single-energy unenhanced and dual-energy contrast-enhanced with synchronous nephrographic–excretory phase scans. DECT-based images [virtual unenhanced (VUE), weighted average, and colour-coded iodine overlay] were reconstructed. Opacification degree by contrast media of the upper urinary tract, and image quality of virtual unenhanced images were independently evaluated using a four-point scale. The diagnostic accuracy in detecting urothelial tumours on DECT-based images was determined. The dose of a theoretical dual-phase single-energy protocol was obtained by multiplying the effective dose of the unenhanced single-energy acquisition by two. Radiation dose saving by omitting the unenhanced scan was calculated. Results: The degree of opacification was scored as optimal or good in 86.9% of cases (k = 0.72); VUE image quality was excellent or good in 83.3% of cases (k = 0.82). Sensitivity, specificity, positive predictive value, and negative predictive value for urothelial tumours detection were 85.7, 98.6, 92.3, and 97.1%. Omission of the unenhanced scan led to a mean dose reduction of 42.7 ± 5%. Conclusion: Single-phase DECT urography with synchronous nephrographic–excretory phase enhancement represents an accurate “all-in-one’’ approach with a radiation dose saving up to 45% compared with a standard dual-phase protocol.

  1. Single-Phase Single-Stage Grid Tied Solar PV System with Active Power Filtering Using Power Balance Theory

    Science.gov (United States)

    Singh, Yashi; Hussain, Ikhlaq; Singh, Bhim; Mishra, Sukumar

    2018-03-01

    In this paper, power quality features such as harmonics mitigation, power factor correction with active power filtering are addressed in a single-stage, single-phase solar photovoltaic (PV) grid tied system. The Power Balance Theory (PBT) with perturb and observe based maximum power point tracking algorithm is proposed for the mitigation of power quality problems in a solar PV grid tied system. The solar PV array is interfaced to a single phase AC grid through a Voltage Source Converter (VSC), which provides active power flow from a solar PV array to the grid as well as to the load and it performs harmonics mitigation using PBT based control. The solar PV array power varies with sunlight and due to this, the solar PV grid tied VSC works only 8-10 h per day. At night, when PV power is zero, the VSC works as an active power filter for power quality improvement, and the load active power is delivered by the grid to the load connected at the point of common coupling. This increases the effective utilization of a VSC. The system is modelled and simulated using MATLAB and simulated responses of the system at nonlinear loads and varying environmental conditions are also validated experimentally on a prototype developed in the laboratory.

  2. Indirect Matrix Converter for Hybrid Electric Vehicle Application with Three-Phase and Single-Phase Outputs

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2015-04-01

    Full Text Available This paper presents an indirect matrix converter (IMC topology for hybrid electric vehicle (HEV application with three-phase and single-phase outputs. The HEV includes mechanical, electrical, control, and electrochemical systems among others. In the mechanical system, a traction motor and a compressor motor are used to drive the HEV. The traction motor and the compressor motor are usually operated as three-phase and single-phase motors, respectively. In this respect, a dual AC-drive system can operate the traction and the compressor motor simultaneously. Furthermore, compared to a conventional dual matrix converter system, the proposed topology can reduce the number of switches that the dual outputs share with a DC-link. The application of this system for HEV has advantages, like long lifetime and reduced volume due to the lack of a DC-link. The proposed control strategy and modulation schemes ensure the sinusoidal input and output waveforms and bidirectional power transmission. The proposed system for the HEV application is verified by simulation and experiments.

  3. A review of single-phase grid-connected inverters for photovoltaic modules

    DEFF Research Database (Denmark)

    Kjaer, Soren Baekhoej; Pedersen, John Kim; Blaabjerg, Frede

    2005-01-01

    -phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out......This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single...

  4. Synchronization in single-phase grid-connected photovoltaic systems under grid faults

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2012-01-01

    The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation and stabil......The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...

  5. Single phase cascaded H5 inverter with leakage current elimination for transformerless photovoltaic system

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Jia, X.; Lu, Z.

    2016-01-01

    Leakage current reduction is one of the important issues for the transformelress PV systems. In this paper, the transformerless single-phase cascaded H-bridge PV inverter is investigated. The common mode model for the cascaded H4 inverter is analyzed. And the reason why the conventional cascade H4...... inverter fails to reduce the leakage current is clarified. In order to solve the problem, a new cascaded H5 inverter is proposed to solve the leakage current issue. Finally, the experimental results are presented to verify the effectiveness of the proposed topology with the leakage current reduction...... for the single-phase transformerless PV systems....

  6. Challenges in thermal design of industrial single-phase power inverter

    Directory of Open Access Journals (Sweden)

    Ninković Predrag

    2016-01-01

    Full Text Available This paper presents the influence of thermal aspects in design process of an industrial single-phase inverter, choice of its topology and components. Stringent design inputs like very high overload level, demand for natural cooling and very wide input voltage range have made conventional circuit topology inappropriate therefore asking for alternative solution. Different power losses calculations in semiconductors are performed and compared, outlining the guidelines how to choose the final topology. Some recommendations in power magnetic components design are given. Based on the final project, a 20kVA single-phase inverter for thermal power plant supervisory and control system is designed and commissioned.

  7. Single-Phase Hybrid Switched Reluctance Motor for Low-Power Low-Cost Applications

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Jakobsen, Uffe

    2011-01-01

    This paper presents a new single-phase, Hybrid Switched Reluctance (HSR) motor for low-cost, low-power, pump or fan drive systems. Its single-phase configuration allows use of a simple converter to reduce the system cost. Cheap ferrite magnets are used and arranged in a special flux concentration...... manner to increase effectively the torque density and efficiency of this machine. The efficiency of this machine is comparable to the efficiency of a traditional permanent magnet machine in the similar power range. The cogging torque, due to the existence of the permanent magnetic field, is beneficially...

  8. An Open-Loop Grid Synchronization Approach for Single-Phase Applications

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Quintero, Juan Carlos Vasquez

    2018-01-01

    in the presence of frequency drifts. This is particularly true in single-phase applications, where the lack of multiple independent input signals makes the implementation of the synchronization technique difficult. The aim of this paper is to develop an effective OLS technique for single-phase power and energy...... applications. The proposed OLS method benefits from a straightforward implementation, a fast dynamic response (a response time less than two cycles of the nominal frequency), and a complete immunity against the DC component in the grid voltage. In addition, the designed OLS method totally blocks (significantly...

  9. Fractional single-phase-lagging heat conduction model for describing anomalous diffusion

    Directory of Open Access Journals (Sweden)

    T.N. Mishra

    2016-03-01

    Full Text Available The fractional single-phase-lagging (FSPL heat conduction model is obtained by combining scalar time fractional conservation equation to the single-phase-lagging (SPL heat conduction model. Based on the FSPL heat conduction model, anomalous diffusion within a finite thin film is investigated. The effect of different parameters on solution has been observed and studied the asymptotic behavior of the FSPL model. The analytical solution is obtained using Laplace transform method. The whole analysis is presented in dimensionless form. Numerical examples of particular interest have been studied and discussed in details.

  10. Modeling and Stability Assessment of Single-Phase Grid Synchronization Techniques

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vasquez, Juan

    2018-01-01

    (GSTs) is of vital importance. This task is most often based on obtaining a linear time-invariant (LTI) model for the GST and applying standard stability tests to it. Another option is modeling and dynamics/stability assessment of GSTs in the linear time-periodic (LTP) framework, which has received...... a very little attention. In this letter, the procedure of deriving the LTP model for single-phase GSTs is first demonstrated. The accuracy of the LTP model in predicting the GST dynamic behavior and stability is then evaluated and compared with that of the LTI one. Two well-known single-phase GSTs, i...

  11. Zero-Voltage Ride-Through Capability of Single-Phase Grid-Connected Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2017-03-01

    Full Text Available Distributed renewable energy systems play an increasing role in today’s energy paradigm. Thus, intensive research activities have been centered on improving the performance of renewable energy systems, including photovoltaic (PV systems, which should be of multiple-functionality. That is, the PV systems should be more intelligent in the consideration of grid stability, reliability, and fault protection. Therefore, in this paper, the performance of single-phase grid-connected PV systems under an extreme grid fault (i.e., when the grid voltage dips to zero is explored. It has been revealed that combining a fast and accurate synchronization mechanism with appropriate control strategies for the zero-voltage ride-through (ZVRT operation is mandatory. Accordingly, the representative synchronization techniques (i.e., the phase-locked loop (PLL methods in the ZVRT operation are compared in terms of detection precision and dynamic response. It shows that the second-order generalized integrator (SOGI-PLL is a promising solution for single-phase systems in the case of fault ride-through. A control strategy by modifying the SOGI-PLL scheme is then introduced to single-phase grid-connected PV systems for ZVRT operation. Simulations are performed to verify the discussions. The results have demonstrated that the proposed method can help single-phase PV systems to temporarily ride through zero-voltage faults with good dynamics.

  12. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    International Nuclear Information System (INIS)

    Serrato, M. G.

    2013-01-01

    located at the Florida International University Applied Research Center, Miami, FL (FIU-ARC). A follow-on fluid injection test was developed to detect fluid and ion migration in a cementitious material/grouted test cube using a limited number of existing embedded sensor systems. This In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) - Phase 3 Fluid Injection Test Summary Report summarizes the test implementation, acquired and processed data, and results from the activated embedded sensor systems used during the fluid injection test. The ISDSN-MSTB Phase 3 Fluid Injection Test was conducted from August 27 through September 6, 2013 at the FIU-ARC ISDSN-MSTB test cube. The fluid injection test activated a portion of the existing embedded sensor systems in the ISDSN-MSTB test cube: Electrical Resistivity Tomography-Thermocouple Sensor Arrays, Advance Tensiometer Sensors, and Fiber Loop Ringdown Optical Sensors. These embedded sensor systems were activated 15 months after initial placement. All sensor systems were remotely operated and data acquisition was completed through the established Sensor Remote Access System (SRAS) hosted on the DOE D&D Knowledge Management Information Tool (D&D DKM-IT) server. The ISDN Phase 3 Fluid Injection Test successfully demonstrated the feasibility of embedding sensor systems to assess moisture-fluid flow and resulting transport potential for contaminate mobility through a cementitious material/grout monolith. The ISDSN embedded sensor systems activated for the fluid injection test highlighted the robustness of the sensor systems and the importance of configuring systems in-depth (i.e., complementary sensors and measurements) to alleviate data acquisition gaps

  13. In Situ Decommissioning Sensor Network, Meso-Scale Test Bed - Phase 3 Fluid Injection Test Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Serrato, M. G.

    2013-09-27

    located at the Florida International University Applied Research Center, Miami, FL (FIU-ARC). A follow-on fluid injection test was developed to detect fluid and ion migration in a cementitious material/grouted test cube using a limited number of existing embedded sensor systems. This In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) - Phase 3 Fluid Injection Test Summary Report summarizes the test implementation, acquired and processed data, and results from the activated embedded sensor systems used during the fluid injection test. The ISDSN-MSTB Phase 3 Fluid Injection Test was conducted from August 27 through September 6, 2013 at the FIU-ARC ISDSN-MSTB test cube. The fluid injection test activated a portion of the existing embedded sensor systems in the ISDSN-MSTB test cube: Electrical Resistivity Tomography-Thermocouple Sensor Arrays, Advance Tensiometer Sensors, and Fiber Loop Ringdown Optical Sensors. These embedded sensor systems were activated 15 months after initial placement. All sensor systems were remotely operated and data acquisition was completed through the established Sensor Remote Access System (SRAS) hosted on the DOE D&D Knowledge Management Information Tool (D&D DKM-IT) server. The ISDN Phase 3 Fluid Injection Test successfully demonstrated the feasibility of embedding sensor systems to assess moisture-fluid flow and resulting transport potential for contaminate mobility through a cementitious material/grout monolith. The ISDSN embedded sensor systems activated for the fluid injection test highlighted the robustness of the sensor systems and the importance of configuring systems in-depth (i.e., complementary sensors and measurements) to alleviate data acquisition gaps.

  14. Isostructural solid-solid phase transition in monolayers of soft core-shell particles at fluid interfaces: structure and mechanics.

    Science.gov (United States)

    Rey, Marcel; Fernández-Rodríguez, Miguel Ángel; Steinacher, Mathias; Scheidegger, Laura; Geisel, Karen; Richtering, Walter; Squires, Todd M; Isa, Lucio

    2016-04-21

    We have studied the complete two-dimensional phase diagram of a core-shell microgel-laden fluid interface by synchronizing its compression with the deposition of the interfacial monolayer. Applying a new protocol, different positions on the substrate correspond to different values of the monolayer surface pressure and specific area. Analyzing the microstructure of the deposited monolayers, we discovered an isostructural solid-solid phase transition between two crystalline phases with the same hexagonal symmetry, but with two different lattice constants. The two phases corresponded to shell-shell and core-core inter-particle contacts, respectively; with increasing surface pressure the former mechanically failed enabling the particle cores to come into contact. In the phase-transition region, clusters of particles in core-core contacts nucleate, melting the surrounding shell-shell crystal, until the whole monolayer moves into the second phase. We furthermore measured the interfacial rheology of the monolayers as a function of the surface pressure using an interfacial microdisk rheometer. The interfaces always showed a strong elastic response, with a dip in the shear elastic modulus in correspondence with the melting of the shell-shell phase, followed by a steep increase upon the formation of a percolating network of the core-core contacts. These results demonstrate that the core-shell nature of the particles leads to a rich mechanical and structural behavior that can be externally tuned by compressing the interface, indicating new routes for applications, e.g. in surface patterning or emulsion stabilization.

  15. Quantum phase transitions in spin-1 X X Z chains with rhombic single-ion anisotropy

    Science.gov (United States)

    Ren, Jie; Wang, Yimin; You, Wen-Long

    2018-04-01

    We explore numerically the inverse participation ratios in the ground state of one-dimensional spin-1 X X Z chains with the rhombic single-ion anisotropy. By employing the techniques of density-matrix renormalization group, effects of the rhombic single-ion anisotropy on various information theoretical measures are investigated, such as the fidelity susceptibility, the quantum coherence, and the entanglement entropy. Their relations with the quantum phase transitions are also analyzed. The phase transitions from the Y -Néel phase to the large-Ex or the Haldane phase can be well characterized by the fidelity susceptibility. The second-order derivative of the ground-state energy indicates all the transitions are of second order. We also find that the quantum coherence, the entanglement entropy, the Schmidt gap, and the inverse participation ratios can be used to detect the critical points of quantum phase transitions. Results drawn from these quantum information observables agree well with each other. Finally we provide a ground-state phase diagram as functions of the exchange anisotropy Δ and the rhombic single-ion anisotropy E .

  16. Fluid-Elastic Instability of U-Tube Bundle in Air-Water Two-Phase Flow

    International Nuclear Information System (INIS)

    Chu, In Cheol; Lee, Chang Hee; Yun, Young Jung; Chung, Heung June

    2007-03-01

    Using steam generator U-tube flow-induced vibration test facility, the flow-induced vibration characteristics of U-tube in row 34-44 and line 71-77 were investigated. Air and water at room temperature and near atmospheric pressure were used as working fluids. In the present experiments, followings were evaluated under two-phase cross-flow condition: the fundamental vibration responses and the critical gap velocity for a fluid-elastic instability of U-tubes, the damping ratio and hydrodynamic mass of U-tubes. In addition, the fluid-elastic instability factor, K, was preliminary assessed using Connors' relation. In the case of the U-tubes which are not supported by partial egg-crate in OPR100 steam generator, it has been found that the vibration displacement of those U-tubes are highly possible to exceed the design limit even by a turbulent excitation mechanism. The damping ratio of U-tubes measured in the present experiments was significantly higher than the OPR1000 steam generator design value. The fluid-elastic instability factor of U-tube bundle obtained in the present experiments were preliminary evaluated to be mostly in the range of 6.5-10.5

  17. The analysis of two-phase flow and heat transfer using a multidimensional, four field, two-fluid model

    International Nuclear Information System (INIS)

    Lahey, Richard T.; Drew, Donald A.

    2001-01-01

    This paper reviews the state-of-the-art in the prediction of multidimensional multiphase flow and heat transfer phenomena using a four field, two-fluid model. It is shown that accurate mechanistic computational fluid dynamic (CFD) predictions are possible for a wide variety of adiabatic and diabatic flows using this computational model. In particular, the model is able to predict the bubbly air/water upflow data of Serizawa (Serizawa, A., 1974. Fluid dynamic characteristics of two-phase flow. Ph.D. thesis, (Nuclear Engineering), Kyoto University, Japan), the downflow data of Wang et al. (Wang, S.K., Lee, S.J., Lahey Jr., R.T., Jones, O.C., 1987. 3-D turbulence structure and phase distribution measurements in bubbly two-phase flows. Int. J. Multiphase Flow 13 (3), 327-343), the isosceles triangle upflow data of Lopez de Bertodano et al. (Lopez de Bertodano, M., Lahey Jr., R.T., Jones, O.C., 1994b. Phase distribution in bubbly two-phase flow in vertical ducts. Int. J. Multiphase Flow 20 (5), 805-818), the heated annular R-113 subcooled boiling data of Velidandala, et al. (Velidandla, V., Pulta, S., Roy, P., Kaira, S.P., 1995. Velocity field in turbulent subcooled boiling flow. ASME Preprint HTD-314, 107-123) and the R-113 CHF data of Hino and Ueda (Hino, R., Ueda, T., 1985. Studies on heat transfer and flow characteristics in subcooled boiling-part 2, flow characteristics. Int. J. Multiphase Flow 11, 283-297). It can also predict external two-phase flows, such as those for spreading two-phase jets (Bonetto, F., Lahey Jr., R.T., 1993. An experimental study on air carryunder due to a plunging liquid jet. Int. J. Multiphase Flow 19 (2), 281-294) and multiphase flows around the hull of naval surface ships (Carrica, P.M., Bonetto, F., Drew, D.A., Lahey, R.T., 1999. A polydispersed model for bubbly two-phase flow around a surface ship. Int. J. Multiphase Flow 25 (2), 257-305)

  18. Effect of phase behavior, density, and isothermal compressibility on the constant-volume heat capacity of ethane + n-pentane mixed fluids in different phase regions

    International Nuclear Information System (INIS)

    Mu, Tiancheng; Liu, Zhimin; Han, Buxing.; Li, Zhonghao; Zhang, Jianling; Zhang, Xiaogang

    2003-01-01

    The phase behavior, density, and constant-volume molar heat capacity (C v,m ) of ethane + n-pentane binary mixtures have been measured in the supercritical region and subcritical region at T=309.45 K. In addition, the isothermal compressibility (κ T ) has been calculated using the density data determined. For a mixed fluid with a composition close to the critical composition, C v,m and κ T increase sharply as the pressure approaches the critical point (CP), the dew point (DP), or the bubble point (BP). However, C v,m is not sensitive to pressure in the entire pressure range if the composition of the mixed fluid is far from the critical composition. To tune the properties of the binary mixtures effectively by pressure, both the composition and the pressure should be close to the critical point of the mixture. The intermolecular interactions in the mixture are also discussed on the basis of the experimental results

  19. Fluid phase equilibria during propylene carbonate synthesis from propylene oxide in carbon dioxide medium

    DEFF Research Database (Denmark)

    Gharnati, Loubna; Musko, Nikolai; Jensen, Anker Degn

    2013-01-01

    -cyclic guanidinium bromide on SBA-15 (HEPCGBr/SBA-15) as catalyst in the absence of any co-catalyst. It was found that the yield was strongly dependent on the amount of CO2 added to the system and that the phase behavior strongly changes along the reaction pathway. The Cubic-Plus-Association (CPA) equation of state...... was used to predict the phase behavior during the reaction and the number and composition of coexisting phases in the multicomponent reaction system were determined. In accordance with the experimental data, the maximum conversion was achieved in the transition region between the two- and the one-phase...... region where a CO2-expanded reactant/product phase (larger volume due to the dissolution of carbon dioxide in the liquid phase) is present. Optimal conditions for performing the reaction have been derived which requires consideration not only of the phase behavior of the starting phase but also...

  20. Circumferential-wave phase velocities for empty, fluid-immersed spherical metal shells

    DEFF Research Database (Denmark)

    Überall, Herbert; Claude Ahyi, A.; Raju, P. K.

    2001-01-01

    Our earlier studies regarding acoustic scattering resonances and the dispersive phase velocities of the surface waves that generate them, have demonstrated the effectiveness of obtaining phase velocity dispersion curves from the known acoustic resonance frequencies, and their accuracy. This possi...

  1. Validation of two-phase CFD models for propellant tank self-pressurization: Crossing fluid types, scales, and gravity levels

    Science.gov (United States)

    Kassemi, Mohammad; Kartuzova, Olga; Hylton, Sonya

    2018-01-01

    This paper examines our computational ability to capture the transport and phase change phenomena that govern cryogenic storage tank pressurization and underscores our strengths and weaknesses in this area in terms of three computational-experimental validation case studies. In the first study, 1g pressurization of a simulant low-boiling point fluid in a small scale transparent tank is considered in the context of the Zero-Boil-Off Tank (ZBOT) Experiment to showcase the relatively strong capability that we have developed in modelling the coupling between the convective transport and stratification in the bulk phases with the interfacial evaporative and condensing heat and mass transfer that ultimately control self-pressurization in the storage tank. Here, we show that computational predictions exhibit excellent temporal and spatial fidelity under the moderate Ra number - high Bo number convective-phase distribution regimes. In the second example, we focus on 1g pressurization and pressure control of the large-scale K-site liquid hydrogen tank experiment where we show that by crossing fluid types and physical scales, we enter into high Bo number - high Ra number flow regimes that challenge our ability to predict turbulent heat and mass transfer and their impact on the tank pressurization correctly, especially, in the vapor domain. In the final example, we examine pressurization results from the small scale simulant fluid Tank Pressure Control Experiment (TCPE) performed in microgravity to underscore the fact that in crossing into a low Ra number - low Bo number regime in microgravity, the temporal evolution of the phase front as affected by the time-dependent residual gravity and impulse accelerations becomes an important consideration. In this case detailed acceleration data are needed to predict the correct rate of tank self-pressurization.

  2. Mathematical modelling and numerical resolution of multi-phase compressible fluid flows problems

    International Nuclear Information System (INIS)

    Lagoutiere, Frederic

    2000-01-01

    This work deals with Eulerian compressible multi-species fluid dynamics, the species being either mixed or separated (with interfaces). The document is composed of three parts. The first parts devoted to the numerical resolution of model problems: advection equation, Burgers equation, and Euler equations, in dimensions one and two. The goal is to find a precise method, especially for discontinuous initial conditions, and we develop non dissipative algorithms. They are based on a downwind finite-volume discretization under some stability constraints. The second part treats of the mathematical modelling of fluids mixtures. We construct and analyse a set of multi-temperature and multi-pressure models that are entropy, symmetrizable, hyperbolic, not ever conservative. In the third part, we apply the ideas developed in the first part (downwind discretization) to the numerical resolution of the partial differential problems we have constructed for fluids mixtures in the second part. We present some numerical results in dimensions one and two. (author) [fr

  3. Modeling Two-Phase Flow and Vapor Cycles Using the Generalized Fluid System Simulation Program

    Science.gov (United States)

    Smith, Amanda D.; Majumdar, Alok K.

    2017-01-01

    This work presents three new applications for the general purpose fluid network solver code GFSSP developed at NASA's Marshall Space Flight Center: (1) cooling tower, (2) vapor-compression refrigeration system, and (3) vapor-expansion power generation system. These systems are widely used across engineering disciplines in a variety of energy systems, and these models expand the capabilities and the use of GFSSP to include fluids and features that are not part of its present set of provided examples. GFSSP provides pressure, temperature, and species concentrations at designated locations, or nodes, within a fluid network based on a finite volume formulation of thermodynamics and conservation laws. This paper describes the theoretical basis for the construction of the models, their implementation in the current GFSSP modeling system, and a brief evaluation of the usefulness of the model results, as well as their applicability toward a broader spectrum of analytical problems in both university teaching and engineering research.

  4. Equation-of-State Modeling of Phase Equilibria in Petroleum Fluids

    DEFF Research Database (Denmark)

    Jørgensen, Marianne

    1996-01-01

    The Soave-Redlich-Kwong (SRK) equation of state was used to investigate and develop several aspects of the modeling of natural petroleum fluids.A new method was presented for numerical evaluation of PVT experiments. This method was used in the estimation of binary interaction parameters. A comphr......The Soave-Redlich-Kwong (SRK) equation of state was used to investigate and develop several aspects of the modeling of natural petroleum fluids.A new method was presented for numerical evaluation of PVT experiments. This method was used in the estimation of binary interaction parameters....... A comphrensive study of pseudoization procedures is presented. It is concluded that the compared methods exhibit results of comparable accuracy, and that six to eight pseudocomponents are needed for optimal representation of petroleum fluids.Finally, it is investigated how well the EOS can represent the VLLE...

  5. Shot-noise-limited monitoring and phase locking of the motion of a single trapped ion.

    Science.gov (United States)

    Bushev, P; Hétet, G; Slodička, L; Rotter, D; Wilson, M A; Schmidt-Kaler, F; Eschner, J; Blatt, R

    2013-03-29

    We perform a high-resolution real-time readout of the motion of a single trapped and laser-cooled Ba+ ion. By using an interferometric setup, we demonstrate a shot-noise-limited measurement of thermal oscillations with a resolution of 4 times the standard quantum limit. We apply the real-time monitoring for phase control of the ion motion through a feedback loop, suppressing the photon recoil-induced phase diffusion. Because of the spectral narrowing in the phase-locked mode, the coherent ion oscillation is measured with a resolution of about 0.3 times the standard quantum limit.

  6. Theory of phase transformation and reorientation in single crystalline shape memory alloys

    International Nuclear Information System (INIS)

    Zhu, J J; Liang, N G; Cai, M; Liew, K M; Huang, W M

    2008-01-01

    A constitutive model, based on an (n+1)-phase mixture of the Mori–Tanaka average theory, has been developed for stress-induced martensitic transformation and reorientation in single crystalline shape memory alloys. Volume fractions of different martensite lattice correspondence variants are chosen as internal variables to describe microstructural evolution. Macroscopic Gibbs free energy for the phase transformation is derived with thermodynamics principles and the ensemble average method of micro-mechanics. The critical condition and the evolution equation are proposed for both the phase transition and reorientation. This model can also simulate interior hysteresis loops during loading/unloading by switching the critical driving forces when an opposite transition takes place

  7. Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

    Science.gov (United States)

    Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

    2018-05-15

    We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

  8. Berry phase of primordial scalar and tensor perturbations in single-field inflationary models

    Science.gov (United States)

    Balajany, Hamideh; Mehrafarin, Mohammad

    2018-06-01

    In the framework of the single-field slow-roll inflation, we derive the Hamiltonian of the linear primordial scalar and tensor perturbations in the form of time-dependent harmonic oscillator Hamiltonians. We find the invariant operators of the resulting Hamiltonians and use their eigenstates to calculate the adiabatic Berry phase for sub-horizon modes in terms of the Lewis-Riesenfeld phase. We conclude by discussing the discrepancy in the results of Pal et al. (2013) [21] for these Berry phases, which is resolved to yield agreement with our results.

  9. Improved state observers for sensorless single phase BLDC-PM motor drives

    DEFF Research Database (Denmark)

    Lepure, Liviu L.; Boldea, Ion; Andreescu, Gheorghe Daniel

    2010-01-01

    Two methods of extracting the rotor position and speed for a sensorless single phase BLDC-PM motor drive by measuring only the phase current are presented here. Both methods are based on a generated orthogonal flux system. The first method extracts the position information by using the tan−1...... function and then an improved observer is created by adding a 4th order harmonic term in the estimated position, while the second method uses a phase locked loop structure. The proposed state observers are detailed using simulation results and then validated by experimental results....

  10. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    International Nuclear Information System (INIS)

    Yu, Xin-Guo; Choi, Ki-Yong

    2015-01-01

    These passive safety systems all rely on the natural circulation to cool down the reactor cores during an accident. Thus, a robust and accurate scaling methodology must be developed and employed to both assist in the design of a scaled-down test facility and guide the tests in order to mimic the natural circulation flow of its prototype. The natural circulation system generally consists of a heat source, the connecting pipes and several heat sinks. Although many applauding scaling methodologies have been proposed during last several decades, few works have been dedicated to systematically analyze and exactly preserve the hydraulic similarity. In the present study, the hydraulic similarity analyses are performed at both system and local level. By this mean, the scaling criteria for the exact hydraulic similarity in a full-pressure model have been sought. In other words, not only the system-level but also the local-level hydraulic similarities are pursued. As the hydraulic characteristics of a fluid system is governed by the momentum equation, the scaling analysis starts with it. A dimensionless integral loop momentum equation is derived to obtain the dimensionless numbers. In the dimensionless momentum equation, two dimensionless numbers, the dimensionless flow resistance number and the dimensionless gravitational force number, are identified along with a unique hydraulic time scale, characterizing the system hydraulic response. A full-height full-pressure model is also made to see which model among the full-height model and reduced-height model can preserve the hydraulic behavior of the prototype. From the dimensionless integral momentum equation, a unique hydraulic time scale, which characterizes the hydraulic response of a single-phase natural circulation system, is identified along with two dimensionless parameters: the dimensionless flow resistance number and the dimensionless gravitational force number. By satisfying the equality of both dimensionless numbers

  11. Scaling Analysis of the Single-Phase Natural Circulation: the Hydraulic Similarity

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xin-Guo; Choi, Ki-Yong [KAERI, Daejeon (Korea, Republic of)

    2015-05-15

    These passive safety systems all rely on the natural circulation to cool down the reactor cores during an accident. Thus, a robust and accurate scaling methodology must be developed and employed to both assist in the design of a scaled-down test facility and guide the tests in order to mimic the natural circulation flow of its prototype. The natural circulation system generally consists of a heat source, the connecting pipes and several heat sinks. Although many applauding scaling methodologies have been proposed during last several decades, few works have been dedicated to systematically analyze and exactly preserve the hydraulic similarity. In the present study, the hydraulic similarity analyses are performed at both system and local level. By this mean, the scaling criteria for the exact hydraulic similarity in a full-pressure model have been sought. In other words, not only the system-level but also the local-level hydraulic similarities are pursued. As the hydraulic characteristics of a fluid system is governed by the momentum equation, the scaling analysis starts with it. A dimensionless integral loop momentum equation is derived to obtain the dimensionless numbers. In the dimensionless momentum equation, two dimensionless numbers, the dimensionless flow resistance number and the dimensionless gravitational force number, are identified along with a unique hydraulic time scale, characterizing the system hydraulic response. A full-height full-pressure model is also made to see which model among the full-height model and reduced-height model can preserve the hydraulic behavior of the prototype. From the dimensionless integral momentum equation, a unique hydraulic time scale, which characterizes the hydraulic response of a single-phase natural circulation system, is identified along with two dimensionless parameters: the dimensionless flow resistance number and the dimensionless gravitational force number. By satisfying the equality of both dimensionless numbers

  12. Derivation of simplified basic equations of gas-liquid two-phase dispersed flow based on two-fluid model

    International Nuclear Information System (INIS)

    Kataoka, Isao; Tomiyama, Akio

    2004-01-01

    The simplified and physically reasonable basic equations for the gas-liquid dispersed flow were developed based on some appropriate assumptions and the treatment of dispersed phase as isothermal rigid particles. Based on the local instant formulation of mass, momentum and energy conservation of the dispersed flow, time-averaged equations were obtained assuming that physical quantities in the dispersed phase are uniform. These assumptions are approximately valid when phase change rate and/or chemical reaction rate are not so large at gas-liquid interface and there is no heat generation in within the dispersed phase. Detailed discussions were made on the characteristics of obtained basic equations and physical meanings of terms consisting the basic equations. It is shown that, in the derived averaged momentum equation, the terms of pressure gradient and viscous momentum diffusion do not appear and, in the energy equation, the term of molecular thermal diffusion heat flux does not appear. These characteristics of the derived equations were shown to be very consistent concerning the physical interpretation of the gas-liquid dispersed flow. Furthermore, the obtained basic equations are consistent with experiments for the dispersed flow where most of averaged physical quantities are obtained assuming that the distributions of those are uniform within the dispersed phase. Investigation was made on the problem whether the obtained basic equations are well-posed or ill-posed for the initial value problem. The eigenvalues of the simplified mass and momentum equations are calculated for basic equations obtained here and previous two-fluid basic equations with one pressure model. Well-posedness and ill-posedness are judged whether the eigenvalues are real or imaginary. The result indicated the newly developed basic equations always constitute the well-posed initial value problem while the previous two-fluid basic equations based on one pressure model constitutes ill

  13. Liquid Phase Deposition of Single-Phase Alpha-Copper-Indium-Diselenide

    Science.gov (United States)

    Hepp, Aloysius F.; Bailey, S.; Cowen, Jonathan; Lucas, L.; Ernst, Frank; Pirouz, P.

    2004-01-01

    The success of exploratory missions in outer space often depends on a highly efficient renewable energy supply, as provided by solar cells. Since future missions will demand large aggregates of solar cells, and space flight is expensive, the solar cells must furthermore be available at low costs and have a long lifetime and high resistance against structural damage introduced by irradiation with high energy electrons and protons. The photovoltaic materials that are presently available only partly fulfill all these requirements. Therefore, we propose to explore a new method for fabricating thin-films for cost-efficient solar cells with very high specific power,high irradiation resistance and long lifetime based on the alpha-phase of the Cu-In-Se system "alpha-CIS."

  14. Single and two-phase flow pressure drop for CANFLEX bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G R; Bullock, D E [Atomic Energy of Canada Limited, Ontario (Canada)

    1999-12-31

    Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)

  15. Single and two-phase flow pressure drop for CANFLEX bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G. R.; Bullock, D. E. [Atomic Energy of Canada Limited, Ontario (Canada)

    1998-12-31

    Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)

  16. Some developments and applications of LES of single phase turbulent flows for nuclear industry

    International Nuclear Information System (INIS)

    Frederic Ducros; Valerie Barthel; Ulrich Bieder; Alexandre Chatelain; Younes Benarafa; Olivier Cioni; Gauthier Fauchet; Philippe Emonot; Patrick Quemere; Bernard Menant; Nicolas Tauveron; Simone Vandroux; Christophe Calvin

    2005-01-01

    Full text of publication follows: The turbulence modelling is an important issue concerning the predictive capability of the CFD codes applied to nuclear reactor safety (NRS), in particular for single-phase flows. Common features of these unsteady high Reynolds number turbulent flows are various regimes (laminar, transitional, fully turbulent) developing in arbitrary complex geometries involving a large extend of standard flow configurations (attached and detached boundary layers, mixing layers, jets in cavity, in cross flows, jet impingement) eventually submitted to buoyancy forces, to dilatation effects and leading to mixing of constituents and temperatures. NRS issues are most of the time related to the eventual knowledge of parietal quantities such as temperature (mean and fluctuating), leading to consider the wall region as a crucial one and to deal with coupled problems. All these features can lead to consider different approaches for turbulence modelling: more or less standard 'Reynolds Average Navier-Stokes equations' closures, Large Eddy Simulations, both of them considered with or without wall functions, with or without large implicit time stepping etc. The development and industrialization of LES as a target of providing 'reference simulations' for NRS are parts of the Trio-U project, developed at CEA for several years [1]. First, the paper presents the current status of LES implementation and some insights on the R and D effort concerning the turbulence modelling. The R and D strategy will be introduced as a result of both the extra-nuclear community know-how on LES and several years of applications of LES for nuclear issues at CEA. It will be shown that LES can be considered as a good candidate to deal with the previous mentioned issues. A large emphasis will be devoted to the R and D on approximate wall conditions, including first the checking of the consistency of standard and advanced wall conditions with LES approach, second specific works dealing

  17. Solid-Phase Extraction Strategies to Surmount Body Fluid Sample Complexity in High-Throughput Mass Spectrometry-Based Proteomics

    Science.gov (United States)

    Bladergroen, Marco R.; van der Burgt, Yuri E. M.

    2015-01-01

    For large-scale and standardized applications in mass spectrometry- (MS-) based proteomics automation of each step is essential. Here we present high-throughput sample preparation solutions for balancing the speed of current MS-acquisitions and the time needed for analytical workup of body fluids. The discussed workflows reduce body fluid sample complexity and apply for both bottom-up proteomics experiments and top-down protein characterization approaches. Various sample preparation methods that involve solid-phase extraction (SPE) including affinity enrichment strategies have been automated. Obtained peptide and protein fractions can be mass analyzed by direct infusion into an electrospray ionization (ESI) source or by means of matrix-assisted laser desorption ionization (MALDI) without further need of time-consuming liquid chromatography (LC) separations. PMID:25692071

  18. Determination of amphetamine-type stimulants in oral fluid by solid-phase microextraction and gas chromatography-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Daniele Z., E-mail: daniele.dzs@dpf.gov.br [Setor Tecnico-Cientifico, Superintendencia Regional do Departamento de Policia Federal no Rio Grande do Sul, 1365 Ipiranga Avenue, Azenha, Zip Code 90160-093 Porto Alegre, Rio Grande do Sul (Brazil); Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil); Boehl, Paula O.; Comiran, Eloisa; Mariotti, Kristiane C. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil); Pechansky, Flavio [Centro de Pesquisa em Alcool e Drogas (CPAD), Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, 2350, Ramiro Barcelos Street, Zip Code 90035-903 Porto Alegre, Rio Grande do Sul (Brazil); Duarte, Paulina C.A.V. [Secretaria Nacional de Politicas sobre Drogas (SENAD), Esplanada dos Ministerios, Block ' A' , 5th floor, Zip Code 70050-907 Brasilia, Distrito Federal (Brazil); De Boni, Raquel [Centro de Pesquisa em Alcool e Drogas (CPAD), Hospital de Clinicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, 2350, Ramiro Barcelos Street, Zip Code 90035-903 Porto Alegre, Rio Grande do Sul (Brazil); Froehlich, Pedro E.; Limberger, Renata P. [Programa de Pos-Graduacao em Ciencias Farmaceuticas, Faculdade de Farmacia, Universidade Federal do Rio Grande do Sul, 2752 Ipiranga Avenue, Santana, Zip Code 90610-000 Porto Alegre, Rio Grande do Sul (Brazil)

    2011-06-24

    Graphical abstract: Highlights: > Propylchloroformate derivatization of amphetamine-type stimulants in oral fluid. > Direct immersion solid-phase microextraction/gas chromatography-mass spectrometry. > Linear range 2(4)-256 ng mL{sup -1}, detection limits 0.5-2 ng mL{sup -1}. > Accuracy 98-112%, precision <15% of RSD, recovery 77-112%. > Importance of residual evaluation in checking model goodness-of-fit. - Abstract: A method for the simultaneous identification and quantification of amphetamine (AMP), methamphetamine (MET), fenproporex (FEN), diethylpropion (DIE) and methylphenidate (MPH) in oral fluid collected with Quantisal{sup TM} device has been developed and validated. Thereunto, in-matrix propylchloroformate derivatization followed by direct immersion solid-phase microextraction and gas chromatography-mass spectrometry were employed. Deuterium labeled AMP was used as internal standard for all the stimulants and analysis was performed using the selected ion monitoring mode. The detector response was linear for the studied drugs in the concentration range of 2-256 ng mL{sup -1} (neat oral fluid), except for FEN, whereas the linear range was 4-256 ng mL{sup -1}. The detection limits were 0.5 ng mL{sup -1} (MET), 1 ng mL{sup -1} (MPH) and 2 ng mL{sup -1} (DIE, AMP, FEN), respectively. Accuracy of quality control samples remained within 98.2-111.9% of the target concentrations, while precision has not exceeded 15% of the relative standard deviation. Recoveries with Quantisal{sup TM} device ranged from 77.2% to 112.1%. Also, the goodness-of-fit concerning the ordinary least squares model in the statistical inference of data has been tested through residual plotting and ANOVA. The validated method can be easily automated and then used for screening and confirmation of amphetamine-type stimulants in drivers' oral fluid.

  19. Single phase computed tomography is equivalent to dual phase method for localizing hyperfunctioning parathyroid glands in patients with primary hyperparathyroidism: a retrospective review

    Directory of Open Access Journals (Sweden)

    Fanny Morón

    2017-08-01

    Full Text Available Objective This study aims to compare the sensitivity of dual phase (non-contrast and arterial versus single phase (arterial CT for detection of hyper-functioning parathyroid glands in patients with primary hyperparathyroidism. Methods The CT scans of thirty-two patients who have biochemical evidence of primary hyperparathyroidism, pathologically proven parathyroid adenomas, and pre-operative multiphase parathyroid imaging were evaluated retrospectively in order to compare the adequacy of single phase vs. dual phase CT scans for the detection of parathyroid adenomas. Results The parathyroid adenomas were localized in 83% of cases on single arterial phase CT and 80% of cases on dual phase CT. The specificity for localization of parathyroid tumor was 96% for single phase CT and 97% for dual phase CT. The results were not significantly different (p = 0.695. These results are similar to those found in the literature for multiphase CT of 55–94%. Conclusions Our study supports the use of a single arterial phase CT for the detection of hyperfunctioning parathyroid adenomas. Advances in knowledge: a single arterial phase CT has similar sensitivity for localizing parathyroid adenomas as dual phase CT and significantly reduces radiation dose to the patient.

  20. An efficiency improved single-phase PFC converter for electric vehicle charger applications

    DEFF Research Database (Denmark)

    Zhu, Dexuan; Tang, Yi; Jin, Chi

    2013-01-01

    This paper presents an efficiency improved single-phase power factor correction (PFC) converter with its target application to plug-in hybrid electric vehicle (PHEV) charging systems. The proposed PFC converter features sinusoidal input current, three-level output characteristic, and wide range...