WorldWideScience

Sample records for stage separation simulation

  1. End-To-End Simulation of Launch Vehicle Trajectories Including Stage Separation Dynamics

    Science.gov (United States)

    Albertson, Cindy W.; Tartabini, Paul V.; Pamadi, Bandu N.

    2012-01-01

    The development of methodologies, techniques, and tools for analysis and simulation of stage separation dynamics is critically needed for successful design and operation of multistage reusable launch vehicles. As a part of this activity, the Constraint Force Equation (CFE) methodology was developed and implemented in the Program to Optimize Simulated Trajectories II (POST2). The objective of this paper is to demonstrate the capability of POST2/CFE to simulate a complete end-to-end mission. The vehicle configuration selected was the Two-Stage-To-Orbit (TSTO) Langley Glide Back Booster (LGBB) bimese configuration, an in-house concept consisting of a reusable booster and an orbiter having identical outer mold lines. The proximity and isolated aerodynamic databases used for the simulation were assembled using wind-tunnel test data for this vehicle. POST2/CFE simulation results are presented for the entire mission, from lift-off, through stage separation, orbiter ascent to orbit, and booster glide back to the launch site. Additionally, POST2/CFE stage separation simulation results are compared with results from industry standard commercial software used for solving dynamics problems involving multiple bodies connected by joints.

  2. Transient Simulations of Gas-Oil-Water Separation Plants

    Directory of Open Access Journals (Sweden)

    Tor S. Schei

    1991-01-01

    Full Text Available A set of mathematical models for the dynamic simulation of offshore processing plants is developed. Each process unit is modeled separately, and the various models are integrated into a system for the simulation of an entire plant. The purpose of the simulation system is to study the effects of various disturbances and investigate appropriate control strategies. Important variables subject to control are pressure, flow rate, temperature, vessel liquid level and compressor speed. In separators the rate of interfacial mass transfer between the liquid and vapour phases at non-equilibrium is modeled as a first order time lag. The vapour liquid equilibrium ratio is linearized with respect to variations in pressure and temperature for each separator stage. A realistic scenario is chosen in order to demonstrate the capabilities of the simulation system.

  3. Numerical simulation of radial compressor stage

    Science.gov (United States)

    Syka, T.; Luňáček, O.

    2013-04-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  4. Numerical simulation of radial compressor stage

    OpenAIRE

    Luňáček O.; Syka T.

    2013-01-01

    Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  5. Numerical simulation of radial compressor stage

    Directory of Open Access Journals (Sweden)

    Luňáček O.

    2013-04-01

    Full Text Available Article describes numerical simulations of air flow in radial compressor stage in NUMECA CFD software. In simulations geometry variants with and without seals are used. During tasks evaluating was observed seals influence on flow field and performance parameters of compressor stage. Also is described CFDresults comparison with results from design software based on experimental measurements and monitoring of influence of seals construction on compressor stage efficiency.

  6. Multicomponent isotope separation in matched abundance ratio cascades composed of stages with large separation factors

    International Nuclear Information System (INIS)

    Von Halle, E.

    1987-06-01

    The concept of the matched abundance ratio cascade and the system of equations for performing multicomponent productivity calculations upon them has proven extremely useful for analyzing the behavior of gaseous diffusion plants in which the stage separation factors are very nearly equal to unity. Recent interest in the gas centrifuge process, in which the separation factor of a single centrifuge can be relatively large, makes desirable the extension of the theory of the matched abundance ratio cascade to cascades composed of stages with large separation factors. Equations permit the calculation of the productivity for simple cascades composed of stages with large separation factors. The concentration gradient of each of the isotopic species present can be calculated and the cascade description can be determined. An illustrative example dealing with the separation of the isotopes of tungsten in a cascade composed of gas centrifuges is included

  7. Equilibrium-Staged Separations Using Matlab and Mathematica

    Science.gov (United States)

    Binous, Housam

    2008-01-01

    We show a new approach, based on the utilization of Matlab and Mathematica, for solving liquid-liquid extraction and binary distillation problems. In addition, the author shares his experience using these two softwares to teach equilibrium staged separations at the National Institute of Applied Sciences and Technology. (Contains 7 figures.)

  8. Development of RLV-TD Stage Separation System

    Science.gov (United States)

    Mohan, Ganesh; Rao, Y. Naga Sreenivasa; Prakash, P.; Subramanian, U. A.; Purushothaman, P.; Premdas, M.; Abraham, Baby; Kishorenath, V.; Jayachandran, T.

    2017-12-01

    Hyper Sonic Experiment (HEX-01), with main focus on the aero thermodynamic characterization and end to end autonomous mission management, is the first in a series of demonstrators planned by ISRO for the development of a Reusable Launch Vehicle (RLV). This paper gives the evolution of the split collet based separation system used in the separation of the spent booster stage from the RLV-Technology Demonstrator Vehicle (TDV). The separation mechanism is very compact, yet has a very high load bearing capacity. The design details and the challenges faced during flight qualification of the system are discussed in this paper. There are a lot of promising areas where this system can be used.

  9. Reliability Omnipotent Analysis For First Stage Separator On The Separation Process Of Gas, Oil And Water

    International Nuclear Information System (INIS)

    Sony Tjahyani, D. T.; Ismu W, Puradwi; Asmara Santa, Sigit

    2001-01-01

    Reliability of industry can be evaluated based on two aspects which are risk and economic aspects. From these points, optimation value can be determined optimation value. Risk of the oil refinery process are fire and explosion, so assessment of this system must be done. One system of the oil refinery process is first stage separator which is used to separate gas, oil and water. Evaluation of reliability for first stage separator system has been done with FAMECA and HAZap method. The analysis results, the probability of fire and explosion of 1.1x10 - 2 3 /hour and 1.2x10 - 1 1 /hour, respectively. The reliability value of the system is high because each undesired event is anticipated with safety system or safety component

  10. CFD Simulations of Soap Separation; CFD-simulering av avsaapning

    Energy Technology Data Exchange (ETDEWEB)

    Birkestad, Per

    2010-07-01

    A part of Vaermeforsk, the 'Skogsindustriella programmet', has identified the possibility to increase the production of tall oil, and hence the competitiveness, in Swedish pulp mills through an increase in the efficiency of the soap separation tanks. Currently, soap is extracted from the black liquor through a sedimentation process where the less dense soap rise to the top of the liquor tank where it is removed through a over-flow ducting at the top of the tank. Vaermeforsk seeks a better understanding of the detailed flow and the separation mechanisms within the liquor tanks and has initiated a study of computational fluid dynamics (CFD) of the tanks. The aim of the study has been threefold; To develop CFD-methods for use in the study of soap separation processes, to investigate the detailed flow within two Swedish liquor tanks and one North American soap skimmer and lastly to develop new design rules for use in future designs of soap separation tanks. The project shows that CFD is a useful tool for the investigation of black liquor and soap flow within a soap separation tank. The CFD simulations of three existing liquor tanks show that the previously used design-rules based on surface loads are inadequate as the actual flow velocities within the tanks are two orders of magnitude larger than those previously used as reference (the surface load). The CFD simulations also show that the black liquor flow, and hence the soap separation, is very sensitive to density variations on the black liquor inlet and temperature variations as small as 1 deg C can significantly affect the liquor flow.

  11. Reynolds averaged simulation of unsteady separated flow

    International Nuclear Information System (INIS)

    Iaccarino, G.; Ooi, A.; Durbin, P.A.; Behnia, M.

    2003-01-01

    The accuracy of Reynolds averaged Navier-Stokes (RANS) turbulence models in predicting complex flows with separation is examined. The unsteady flow around square cylinder and over a wall-mounted cube are simulated and compared with experimental data. For the cube case, none of the previously published numerical predictions obtained by steady-state RANS produced a good match with experimental data. However, evidence exists that coherent vortex shedding occurs in this flow. Its presence demands unsteady RANS computation because the flow is not statistically stationary. The present study demonstrates that unsteady RANS does indeed predict periodic shedding, and leads to much better concurrence with available experimental data than has been achieved with steady computation

  12. Polymer solution phase separation: Microgravity simulation

    Science.gov (United States)

    Cerny, Lawrence C.; Sutter, James K.

    1989-01-01

    In many multicomponent systems, a transition from a single phase of uniform composition to a multiphase state with separated regions of different composition can be induced by changes in temperature and shear. The density difference between the phase and thermal and/or shear gradients within the system results in buoyancy driven convection. These differences affect kinetics of the phase separation if the system has a sufficiently low viscosity. This investigation presents more preliminary developments of a theoretical model in order to describe effects of the buoyancy driven convection in phase separation kinetics. Polymer solutions were employed as model systems because of the ease with which density differences can be systematically varied and because of the importance of phase separation in the processing and properties of polymeric materials. The results indicate that the kinetics of the phase separation can be performed viscometrically using laser light scattering as a principle means of following the process quantitatively. Isopycnic polymer solutions were used to determine the viscosity and density difference limits for polymer phase separation.

  13. Membrane Modeling, Simulation and Optimization for Propylene/Propane Separation

    KAUST Repository

    Alshehri, Ali

    2015-06-01

    , product purity and the recovery ratio. These findings were utilized to develop simple and accurate empirical correlations to predict the attainability behavior in real membranes, which showed good agreement with experimental and simulation results for various applications. Furthermore, the attainability of the most promising two and three-stage membrane systems are discussed by considering the complete well mixed assumption. The same behaviors that describe single-stage attainability are also recognized for multiple-stages. This discussion leads to a major discovery regarding the nature of the relationship between the attainability parameters in a multiple-stage membrane system with that of a single-stage system. Study of the economics of the multiple-stage membrane process for propylene/propane separation identifies the technology as a potential alternative to the conventional distillation process, even at the existing membrane performance, but conditionally at low to moderate membrane cost and sufficient durability. To study the energy efficiency of membrane retrofitting to an existing distillation process, a shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane and distillation processes. It was discovered that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage, when selectivity is low, the membrane process is not competitive to the distillation process. At the second medium selectivity stage, the membrane/distillation hybrid system can help to reduce the energy consumption; the higher the membrane selectivity the lower the energy requirement. The energy conservation is further improved as the pressure ratio increases. At the third stage, when both the selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit, resulting in a significant reduction in energy consumption

  14. Numerical simulation of separated flows in channels

    Science.gov (United States)

    Louda, Petr; Příhoda, Jaromír; Sváček, Petr; Kozel, Karel

    2012-04-01

    The work deals with numerical modelling of turbulent flows in channels with an expansion of the cross-section where flow separation and reattachment occur. The performance of several eddy viscosity models and an explicit algebraic Reynolds stress model (EARSM) is studied. The used test cases are flows in channels with various backward facing steps where the step is perpendicular or inclined and the top wall is parallel or deflected. Furthermore, a channel with the circular ramp is considered. The numerical solution is achieved by the finite volume method or by the finite element method. The results of both numerical approaches are compared.

  15. Simulation of Pressure-swing Distillation for Separation of Ethyl Acetate-Ethanol-Water

    Science.gov (United States)

    Yang, Jing; Zhou, Menglin; Wang, Yujie; Zhang, Xi; Wu, Gang

    2017-12-01

    In the light of the azeotrope of ethyl acetate-ethanol-water, a process of pressure-swing distillation is proposed. The separation process is simulated by Aspen Plus, and the effects of theoretical stage number, reflux ratio and feed stage about the pressure-swing distillation are optimized. Some better process parameters are as follows: for ethyl acetate refining tower, the pressure is 500.0 kPa, theoretical stage number is 16, reflux ratio is 0.6, feed stage is 5; for crude ethanol tower, the pressure is 101.3 kPa, theoretical stage number is 15, reflux ratio is 0.3, feed stage is 4; for ethanol tower, the pressure is 101.3 kPa, theoretical stage number is 25, reflux ratio is 1.2, feed stage is 10. The mass fraction of ethyl acetate in the bottom of the ethyl acetate refining tower reaches 0.9990, the mass fraction of ethanol in the top of the ethanol tower tower reaches 0.9017, the mass fraction of water in the bottom of the ethanol tower tower reaches 0.9622, and there is also no ethyl acetate in the bottom of the ethanol tower. With laboratory tests, experimental results are in good agreement with the simulation results, which indicates that the separation of ethyl acetate ethanol water can be realized by the pressure-swing distillation separation process. Moreover, it has certain practical significance to industrial practice.

  16. The genetic covariance between life cycle stages separated by metamorphosis.

    Science.gov (United States)

    Aguirre, J David; Blows, Mark W; Marshall, Dustin J

    2014-08-07

    Metamorphosis is common in animals, yet the genetic associations between life cycle stages are poorly understood. Given the radical changes that occur at metamorphosis, selection may differ before and after metamorphosis, and the extent that genetic associations between pre- and post-metamorphic traits constrain evolutionary change is a subject of considerable interest. In some instances, metamorphosis may allow the genetic decoupling of life cycle stages, whereas in others, metamorphosis could allow complementary responses to selection across the life cycle. Using a diallel breeding design, we measured viability at four ontogenetic stages (embryo, larval, juvenile and adult viability), in the ascidian Ciona intestinalis and examined the orientation of additive genetic variation with respect to the metamorphic boundary. We found support for one eigenvector of G: (gobsmax ), which contrasted larval viability against embryo viability and juvenile viability. Target matrix rotation confirmed that while gobsmax shows genetic associations can extend beyond metamorphosis, there is still considerable scope for decoupled phenotypic evolution. Therefore, although genetic associations across metamorphosis could limit that range of phenotypes that are attainable, traits on either side of the metamorphic boundary are capable of some independent evolutionary change in response to the divergent conditions encountered during each life cycle stage. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  17. Simulation models for food separation by adsorption process

    African Journals Online (AJOL)

    Separation of simulated industrial food products, by method of adsorption, has been studied. A thermodynamic approach has been applied to study the liquid adsorption where benzene and cyclohexane have been used to simulate edible oils in a system that employs silica gel as the adsorbent. Different models suggested ...

  18. Simulation models for food separation by adsorption process | Aoyi ...

    African Journals Online (AJOL)

    Separation of simulated industrial food products, by method of adsorption, has been studied. A thermodynamic approach has been applied to study the liquid adsorption where benzene and cyclohexane have been used to simulate edible oils in a system that employs silica gel as the adsorbent. Different models suggested ...

  19. Optimizing Chromatographic Separation: An Experiment Using an HPLC Simulator

    Science.gov (United States)

    Shalliker, R. A.; Kayillo, S.; Dennis, G. R.

    2008-01-01

    Optimization of a chromatographic separation within the time constraints of a laboratory session is practically impossible. However, by employing a HPLC simulator, experiments can be designed that allow students to develop an appreciation of the complexities involved in optimization procedures. In the present exercise, a HPLC simulator from "JCE…

  20. A Two-Stage MMSE Beamformer for Underdetermined Signal Separation

    Czech Academy of Sciences Publication Activity Database

    Koldovský, Zbyněk; Tichavský, Petr; Phan, A. H.; Cichocki, A.

    2013-01-01

    Roč. 20, č. 12 (2013), s. 1227-1230 ISSN 1070-9908 Grant - others:GA ČR(CZ) GAP103/11/1947 Program:GA Institutional support: RVO:67985556 Keywords : beamforming * underdetermined mixtures * blind source separation Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.639, year: 2013 http://library.utia.cas.cz/separaty/2014/SI/koldovsky-0424112.pdf

  1. Transient Modeling of High Altitude Rocket Stage Separation (Preprint)

    Science.gov (United States)

    2007-07-31

    examined flow over moving microbeams using both continuum (Navier-Stokes) and kinetic (DSMC) approaches. There is therefore a large gap between the...403–441. 3Gallis, M.A., Torczinki, J.R., “Simulation of moving microbeams with the Direct Simulation Monte Carlo method,” AIAA Paper 2003-4013...Performance Computing Applications” AMOS 2003 Technical Conference , 10 September, Maui, Hawaii, 2003. 21 of 21 American Institute of Aeronautics and Astronautics Distribution A: Approved for public release; distribution unlimited

  2. Simulation of startup period of hydrogen isotope separation distillation column

    International Nuclear Information System (INIS)

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, Eh.P.

    2003-01-01

    Kinetic procedure for the mathematical simulation of start-up regime of rectification columns for molecular hydrogen isotope separation was developed. Nonstationary state (start-up period) of separating column for rectification of multi-component mixture was calculated. Full information on equilibrium and kinetic physicochemical properties of components in separating mixtures was used for the calculations. Profile of concentration of components by height of column in task moment of time was calculated by means of differential equilibriums of nonstationary mass transfer. Calculated results of nonstationary state of column by the 2 m height, 30 mm diameter during separation of the mixture: 5 % protium, 70 % deuterium, 25 % tritium were illustrated [ru

  3. Simulation and comparison of equilibrium and nonequilibrium stage ...

    African Journals Online (AJOL)

    In the present study, two distinctly different approaches are followed for modelling of reactive distillation column, the equilibrium stage model and the nonequilibrium stage model. These models are simulated with a computer code developed in the present study using MATLAB programming. In the equilibrium stage models, ...

  4. Structural integration of separation and reaction systems: I. Integration of stage-wise processes

    Directory of Open Access Journals (Sweden)

    Mitrović Milan

    2002-01-01

    Full Text Available The structural integration of separation processes, using multifunctional equipment, has been studied on four stage-wise liquid-liquid separations extraction, absorption, distillation, adsorption and on some combinations of these processes. It was shown for stage - wise processes that the ultimate aim of equipment integration is 3-way integration (by components by steps and by stages and that membrane multiphase contactors present concerning the equipment optimal solutions in many cases. First, by using partially integrated equipment and, later by developing fully integrated systems it was experimentally confirmed that structural 3-way integration produces much higher degrees of component separations and component enrichments in compact and safe equipment.

  5. Numerical simulation of the separating performance of hydrocyclones

    Energy Technology Data Exchange (ETDEWEB)

    Ba, Z.S.; Wang, H.L. [Institute of Pressure Vessel and Process Equipment, East China University of Science and Technology, Shanghai (China)

    2006-10-15

    The flow behavior in hydrocyclones is quite complex. The Computational Fluid Dynamics (CFD) method was used to simulate the flow fields inside a hydrocyclone in order to improve its separation efficiency. The RSM turbulent model (Reynolds Stress Model), which abandons the isotropic eddy-viscosity hypothesis, was used to analyze the highly swirling flow fields in hydrocyclones. The ASM Model (Algebraic Slip Mixture Model) was used to simulate the separation performance. The volume fraction distribution and grade efficiency curve are given. The separating efficiency for 60 {mu}m water particles is more than 90 %. The majority of 60 {mu}m water particles are carried to the underflow. An increase in particle size will improve the efficiency by increasing the centrifugal force on the particles. Based on the simulation, the effects of the overflow tube dimensions on the separation performance were studied. The overflow tube dimensions of the hydrocyclone were modified, and the results showed that the Reynolds Stress Model successfully predicted the characteristics of the flow, and the simulated performances were in good agreement with those obtained by tests. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  6. Simulation Model of Membrane Gas Separator Using Aspen Custom Modeler

    Energy Technology Data Exchange (ETDEWEB)

    Song, Dong-keun [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Shin, Gahui; Yun, Jinwon; Yu, Sangseok [Chungnam Nat’l Univ., Daejeon (Korea, Republic of)

    2016-12-15

    Membranes are used to separate pure gas from gas mixtures. In this study, three different types of mass transport through a membrane were developed in order to investigate the gas separation capabilities of a membrane. The three different models typically used are a lumped model, a multi-cell model, and a discretization model. Despite the multi-cell model producing similar results to a discretization model, the discretization model was selected for this investigation, due to the cell number dependence of a multi-cell model. The mass transport model was then used to investigate the effects of pressure difference, flow rate, total exposed area, and permeability. The results showed that the pressure difference increased with the stage cut, but the selectivity was a trade-off for the increasing pressure difference. Additionally, even though permeability is an important parameter, the selectivity and stage cut of the membrane converged as permeability increased.

  7. Used nuclear fuel separations process simulation and testing

    International Nuclear Information System (INIS)

    Pereira, C.; Krebs, J.F.; Copple, J.M.; Frey, K.E.; Maggos, L.E.; Figueroa, J.; Willit, J.L.; Papadias, D.D.

    2013-01-01

    Recent efforts in separations process simulation at Argonne have expanded from the traditional focus on solvent extraction flowsheet design in order to capture process dynamics and to simulate other components, processing and systems of a used nuclear fuel reprocessing plant. For example, the Argonne Model for Universal Solvent Extraction (AMUSE) code has been enhanced to make it both more portable and more readily extensible. Moving away from a spreadsheet environment makes the addition of new species and processes simpler for the expert user, which should enable more rapid implementation of chemical models that simulate evolving processes. The dyAMUSE (dynamic AMUSE) version allows the simulation of transient behavior across an extractor. Electrochemical separations have now been modeled using spreadsheet codes that simulate the electrochemical recycle of fast reactor fuel. The user can follow the evolution of the salt, products, and waste compositions in the electro-refiner, cathode processors, and drawdown as a function of fuel batches treated. To further expand capabilities in integrating multiple unit operations, a platform for linking mathematical models representing the different operations that comprise a reprocessing facility was adapted to enable systems-level analysis and optimization of facility functions. (authors)

  8. Used nuclear fuel separations process simulation and testing

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, C.; Krebs, J.F.; Copple, J.M.; Frey, K.E.; Maggos, L.E.; Figueroa, J.; Willit, J.L.; Papadias, D.D. [Argonne National Laboratory: 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2013-07-01

    Recent efforts in separations process simulation at Argonne have expanded from the traditional focus on solvent extraction flowsheet design in order to capture process dynamics and to simulate other components, processing and systems of a used nuclear fuel reprocessing plant. For example, the Argonne Model for Universal Solvent Extraction (AMUSE) code has been enhanced to make it both more portable and more readily extensible. Moving away from a spreadsheet environment makes the addition of new species and processes simpler for the expert user, which should enable more rapid implementation of chemical models that simulate evolving processes. The dyAMUSE (dynamic AMUSE) version allows the simulation of transient behavior across an extractor. Electrochemical separations have now been modeled using spreadsheet codes that simulate the electrochemical recycle of fast reactor fuel. The user can follow the evolution of the salt, products, and waste compositions in the electro-refiner, cathode processors, and drawdown as a function of fuel batches treated. To further expand capabilities in integrating multiple unit operations, a platform for linking mathematical models representing the different operations that comprise a reprocessing facility was adapted to enable systems-level analysis and optimization of facility functions. (authors)

  9. A nodalization study of steam separator in real time simulation

    International Nuclear Information System (INIS)

    Horugshyang, Lein; Luh, R.T.J.; Zen-Yow, Wang

    1999-01-01

    The motive of this paper is to investigate the influence of steam separator nodalization on reactor thermohydraulics in terms of stability and level response. Three different nodalizations of steam separator are studied by using THEATRE and REMARK Code in a BWR simulator. The first nodalization is the traditional one with two nodes for steam separator. In this nodalization, the steam separation is modeled in the outer node, i.e., upper downcomer. Separated steam enters the Steen dome node and the liquid goes to the feedwater node. The second nodalization is similar to the first one with the steam separation modeled in the inner node. There is one additional junction connecting steam dome node and the inner node. The liquid fallback junction connects the inner node and feedwater node. The third nodalization is a combination of the former two with an integrated node for steam separator. Boundary conditions in this study are provided by a simplified feedwater and main steam driver. For comparison purpose, three tests including full power steady state initialisation, recirculation pumps runback and reactor scram are conducted. Major parameters such as reactor pressure, reactor level, void fractions, neutronic power and junction flows are recorded for analysis. Test results clearly show that the first nodalization is stable for steady state initialisation. However it has too responsive level performance in core flow reduction transients. The second nodalization is the closest representation of real plant structure, but not the performance. Test results show that an instability occurs in the separator region for both steady state initialisation and transients. This instability is caused by an unbalanced momentum in the dual loop configuration. The magnitude of the oscillation reduces as the power decreases. No superiority to the other nodalizations is shown in the test results. The third nodalization shows both stability and responsiveness in the tests. (author)

  10. About the theory of initial stage of oil accumulation in a dome-separator

    Science.gov (United States)

    Gimaltdinov, I. K.; Kildibaeva, S. R.

    2015-05-01

    A mathematical model was developed for accumulation of oil in a cylindrical tank (the dome-separator) designed for capturing of oil from oil leakage at the sea bottom. Two key stages were described, and time dependencies for interface evolution and alcohol layer temperature were calculated.

  11. Aerodynamic Analyses and Database Development for Ares I Vehicle First Stage Separation

    Science.gov (United States)

    Pamadi, Bandu N.; Pei, Jing; Pinier, Jeremy T.; Holland, Scott D.; Covell, Peter F.; Klopfer, Goetz, H.

    2012-01-01

    This paper presents the aerodynamic analysis and database development for the first stage separation of the Ares I A106 Crew Launch Vehicle configuration. Separate databases were created for the first stage and upper stage. Each database consists of three components: isolated or free-stream coefficients, power-off proximity increments, and power-on proximity increments. The power-on database consists of three parts, all plumes firing at nominal conditions, the one booster deceleration motor out condition, and the one ullage settling motor out condition. The isolated and power-off incremental databases were developed using wind tunnel test data. The power-on proximity increments were developed using CFD solutions.

  12. On the performance simulation of inter-stage turbine reheat

    International Nuclear Information System (INIS)

    Pellegrini, Alvise; Nikolaidis, Theoklis; Pachidis, Vassilios; Köhler, Stephan

    2017-01-01

    Highlights: • An innovative gas turbine performance simulation methodology is proposed. • It allows to perform DP and OD performance calculations for complex engines layouts. • It is essential for inter-turbine reheat (ITR) engine performance calculation. • A detailed description is provided for fast and flexible implementation. • The methodology is successfully verified against a commercial closed-source software. - Abstract: Several authors have suggested the implementation of reheat in high By-Pass Ratio (BPR) aero engines, to improve engine performance. In contrast to military afterburning, civil aero engines would aim at reducing Specific Fuel Consumption (SFC) by introducing ‘Inter-stage Turbine Reheat’ (ITR). To maximise benefits, the second combustor should be placed at an early stage of the expansion process, e.g. between the first and second High-Pressure Turbine (HPT) stages. The aforementioned cycle design requires the accurate simulation of two or more turbine stages on the same shaft. The Design Point (DP) performance can be easily evaluated by defining a Turbine Work Split (TWS) ratio between the turbine stages. However, the performance simulation of Off-Design (OD) operating points requires the calculation of the TWS parameter for every OD step, by taking into account the thermodynamic behaviour of each turbine stage, represented by their respective maps. No analytical solution of the aforementioned problem is currently available in the public domain. This paper presents an analytical methodology by which ITR can be simulated at DP and OD. Results show excellent agreement with a commercial, closed-source performance code; discrepancies range from 0% to 3.48%, and are ascribed to the different gas models implemented in the codes.

  13. Magnetic separation in microfluidic systems using microfabricated electromagnets - Experiments and simulations

    DEFF Research Database (Denmark)

    Smistrup, Kristian; Hansen, Ole; Bruus, Henrik

    2005-01-01

    We present experiments and simulations of magnetic separation of magnetic beads in a microfluidic channel. The separation is obtained by microfabricated electromagnets. The results of our simulations using FEMLAB and Mathematica are compared with experimental results obtained using our own...

  14. Inventory simulation tools: Separating nuclide contributions to radiological quantities

    Directory of Open Access Journals (Sweden)

    Gilbert Mark R.

    2017-01-01

    Full Text Available The activation response of a material is a primary factor considered when evaluating its suitability for a nuclear application. Various radiological quantities, such as total (becquerel activity, decay heat, and γ dose, can be readily predicted via inventory simulations, which numerically evolve in time the composition of a material under exposure to neutron irradiation. However, the resulting data sets can be very complex, often necessarily resulting in an over-simplification of the results – most commonly by just considering total response metrics. A number of different techniques for disseminating more completely the vast amount of data output from, in particular, the FISPACT-II inventory code system, including importance diagrams, nuclide maps, and primary knock-on atom (PKA spectra, have been developed and used in scoping studies to produce database reports for the periodic table of elements. This paper introduces the latest addition to this arsenal – standardised and automated plotting of the time evolution in a radiological quantity for a given material separated by contributions from dominant radionuclides. Examples for relevant materials under predicted fusion reactor conditions, and for bench-marking studies against decay-heat measurements, demonstrate the usefulness and power of these radionuclide-separated activation plots.

  15. Inventory simulation tools: Separating nuclide contributions to radiological quantities

    Science.gov (United States)

    Gilbert, Mark R.; Fleming, Michael; Sublet, Jean-Christophe

    2017-09-01

    The activation response of a material is a primary factor considered when evaluating its suitability for a nuclear application. Various radiological quantities, such as total (becquerel) activity, decay heat, and γ dose, can be readily predicted via inventory simulations, which numerically evolve in time the composition of a material under exposure to neutron irradiation. However, the resulting data sets can be very complex, often necessarily resulting in an over-simplification of the results - most commonly by just considering total response metrics. A number of different techniques for disseminating more completely the vast amount of data output from, in particular, the FISPACT-II inventory code system, including importance diagrams, nuclide maps, and primary knock-on atom (PKA) spectra, have been developed and used in scoping studies to produce database reports for the periodic table of elements. This paper introduces the latest addition to this arsenal - standardised and automated plotting of the time evolution in a radiological quantity for a given material separated by contributions from dominant radionuclides. Examples for relevant materials under predicted fusion reactor conditions, and for bench-marking studies against decay-heat measurements, demonstrate the usefulness and power of these radionuclide-separated activation plots. Note to the reader: the pdf file has been changed on September 22, 2017.

  16. Surgical management of stage I and II vulvar cancer:The role of the separated incision

    Directory of Open Access Journals (Sweden)

    Andrijono Andrijono

    2003-06-01

    Full Text Available Vulvar cancer is a gynecological cancer whose incidence rate is relatively low. Patients generally were admitted at advanced stage, and radiation therapy at advanced stage does not provide favorable prognosis. Two main modalities in the treatment of vulvar cancer are surgery and radiation therapy. However, radiation can be performed in early stage vulvar cancer but surgery is thought to have more benefits, such as in side effect on the ovary/ reproductive function disorder, patient's hygiene factor, and the ease in performing therapy if recurrence occurs. There are various techniques of vulvar cancer surgery, such as radical vulvectomy with butterfly incision (RVBI and radical vulvectomy with separated incision (RVSI. The objective of this study was to identify the benefits of radical vulvectomy with separated incision in comparison with radical vulvectomy with butterfly incision in terms of the length of surgery, wound recovery, infection incidence, length of hospital stay. This study was a clinical trial performed during the period of 1990-2000. Fifteen cases of vulvar cancer were found and underwent surgery. Fourteen cases were at stage II and 14 cases were histologically defined as squamous-cell carcinoma and 1 case was adenocarcinoma. The average length of surgery in RVSI was 168 minutes, this was shorter than that in VRBI which reached an average of 275 minutes. The incidence of infection in RVSI group was 3 of 11 cases (27.27%, while in RVBI group all cases had infection in surgical wound. Failure of surgical wound approximation was 1 of 12 cases (9.99%, while in RVBI all cases experienced the failure such that cosmetic surgery was required. Length of postoperative care in RVSI group was 12.3 days, while in RVBI 21.5 days. Thus, complications in VRBI were lower, and length of surgery and length of postoperative care were shorter. (Med J Indones 2003; 12: 103-8 Keywords: vulvar cancer, separated incision

  17. Estimation of Supersonic Stage Separation Aerodynamics of Winged-Body Launch Vehicles Using Response Surface Methods

    Science.gov (United States)

    Erickson, Gary E.

    2010-01-01

    Response surface methodology was used to estimate the longitudinal stage separation aerodynamic characteristics of a generic, bimese, winged multi-stage launch vehicle configuration at supersonic speeds in the NASA LaRC Unitary Plan Wind Tunnel. The Mach 3 staging was dominated by shock wave interactions between the orbiter and booster vehicles throughout the relative spatial locations of interest. The inference space was partitioned into several contiguous regions within which the separation aerodynamics were presumed to be well-behaved and estimable using central composite designs capable of fitting full second-order response functions. The underlying aerodynamic response surfaces of the booster vehicle in belly-to-belly proximity to the orbiter vehicle were estimated using piecewise-continuous lower-order polynomial functions. The quality of fit and prediction capabilities of the empirical models were assessed in detail, and the issue of subspace boundary discontinuities was addressed. Augmenting the central composite designs to full third-order using computer-generated D-optimality criteria was evaluated. The usefulness of central composite designs, the subspace sizing, and the practicality of fitting lower-order response functions over a partitioned inference space dominated by highly nonlinear and possibly discontinuous shock-induced aerodynamics are discussed.

  18. Low Resolution Simulation Screening of Early Stage Acquisition Decisions: Focus on Rapid Prototyping

    OpenAIRE

    Price, Shane

    2012-01-01

    MOVES Research & Education Systems Seminar: Presentation; Session 11: Simulation Modeling for Analysis; Moderator: Arnie Buss; Low Resolution Simulation Screening of Early Stage Acquisition Decisions; speaker: Maj. Shane Price

  19. Three-stage classical molecular dynamics model for simulation of heavy-ion fusion

    Directory of Open Access Journals (Sweden)

    Godre Subodh S.

    2015-01-01

    Full Text Available A three-stage Classical Molecular Dynamics (3S-CMD approach for heavy-ion fusion is developed. In this approach the Classical Rigid-Body Dynamics simulation for heavy-ion collision involving light deformed nucleus is initiated on their Rutherford trajectories at very large initial separation. Collision simulation is then followed by relaxation of the rigid-body constrains for one or both the colliding nuclei at distances close to the barrier when the trajectories of all the nucleons are obtained in a Classical Molecular Dynamics approach. This 3S-CMD approach explicitly takes into account not only the long range Coulomb reorientation of the deformed collision partner but also the internal vibrational excitations of one or both the nuclei at distances close to the barrier. The results of the dynamical simulation for 24Mg+208Pb collision show significant modification of the fusion barrier and calculated fusion cross sections due to internal excitations.

  20. The Analysis, Optimization, and Simulation of a Two-Stage Tandem Queueing Model with Hyperexponential Service Time at Second Stage

    Directory of Open Access Journals (Sweden)

    Vedat Sağlam

    2015-01-01

    Full Text Available The aim of this paper is to analyze a tandem queueing model with two stages. The arrivals to the first stage are Poisson stream and the service time at this stage is exponential. There is no waiting room at first stage. The service time is hyperexponential and no waiting is allowed at second stage. The transition probabilities and loss probabilities of this model are obtained. In addition, the loss probability at second stage is optimized. Performance measures and the variance of the numbers of customers of this tandem queueing model are found. It is seen that the numbers of customers in first stage and second stage are dependent. Finally we have simulated this queueing model. For different values of parameters, exact values, simulated values, and optimal values of obtained performance measures of this model are numerically shown in tables and graphs.

  1. Using a Commercial Simulator to Teach Sorption Separations

    Science.gov (United States)

    Wankat, Phillip C.

    2006-01-01

    The commercial simulator Aspen Chromatography was used in the computer laboratory of a dual-level course. The lab assignments used a cookbook approach to teach basic simulator operation and open-ended exploration to understand adsorption. The students learned theory better than in previous years despite having less lecture time. Students agreed…

  2. Data supporting the validation of a simulation model for multi-component gas separation in polymeric membranes.

    Science.gov (United States)

    Giordano, Lorena; Roizard, Denis; Bounaceur, Roda; Favre, Eric

    2016-12-01

    The article describes data concerning the separation performances of polymeric hollow-fiber membranes. The data were obtained using a model for simulating gas separation, described in the research article entitled "Interplay of inlet temperature and humidity on energy penalty for CO 2 post-combustion capture: rigorous analysis and simulation of a single stage gas permeation process" (L. Giordano, D. Roizard, R. Bounaceur, E. Favre, 2016) [1]. The data were used to validate the model by comparison with literature results. Considering a membrane system based on feed compression only, data from the model proposed and that from literature were compared with respect to the molar composition of permeate stream, the membrane area and specific energy requirement, varying the feed pressure and the CO 2 separation degree.

  3. NDDP multi-stage flash desalination process simulator design

    International Nuclear Information System (INIS)

    Chatterjee, M.; Sashi Kumar, G.N.; Mahendra, A.K.; Sanyal, A.; Gouthaman, G.

    2006-05-01

    A majority of large-scale desalination plants all over the world employ multi-stage flash (MSF) distillation process. Many of these MSF desalination plants have been set up near to nuclear power plants (generally called as nuclear desalination plants) to effectively utilize the low-grade steam from the power plants as the source of energy. A computer program called MSFSIM has been developed to simulate the MSF desalination plant operation both for steady state and various transients including start up. This code predicts the effect of number of stages, flashing temperature, velocity of brine flowing through the tubes of brine heater and evaporators, temperature of the condensing thin film etc. on the plant performance ratio. Such a code can be used for the design of a new plant and to predict its operating and startup characteristics. The code has been extensively validated with available start up data from the pilot MSF desalination plant of 425-m3/day capacity at Trombay, Mumbai. A MSF desalination plant of 4500-m3/day capacity is under construction by BARC at Kalpakkam, which will utilize the steam from Madras Atomic Power Station (MAPS). In this present work extensive parametric study of the 4500-m3/day capacity desalination plant at Kalpakkam has been done using the code MSFSIM for optimizing the operating parameters in order to maximize the performance ratio for stable plant operation. The aim of the work is prediction of plant performance under different operating conditions. (author)

  4. Nbody Simulation Of Planetary Spin In Runaway/oligarchic Stages

    Science.gov (United States)

    Matsukura, Daishi; Kokubo, E.; Ida, S.

    2011-09-01

    In our planetary system, all planets are rotating with wide varieties of obliquities and spin rates. Especially current spin properties of terrestrial planets give us much useful information to constrain the scenario of planetary formation. Ohtsuki and Ida(1998) have investigated the spin of protoplanet which accreted in a disk of planetesimals with non uniform spatial distribution. Their three-body calculations show that the current spin values of the Earth-Moon system is achieved by planetesimal accretion only in the case planetesimals are initially existing around the feeding zones of the protoplanet. In our study, we calculate the whole process of planetary spin by Nbody simulations during their growth stage. Our results show that the distribution of runaway bodies' obliquities are nearly isotropic after runaway growth stage. Additionally, planetesimals acquire their spin angular velocity up to their break-up speed but afterward runaway bodies begin to lose their spin angular velocity as they eat other small bodies. According to our results, runaway bodies statistically have rotation periods between 1-10 hours.

  5. Lacan - a global simulation code for laser isotope separation

    International Nuclear Information System (INIS)

    Goldstein, S.; Quaegebeur, J.P.

    1990-01-01

    Dimensioning a Laser Isotope Separation (LIS) plant means calculating the values of a large number of parameters in order to optimize some objective function. In such algorithms the calculation of the objective function must be repeated thousands of times, therefore each elementary calculation must consume little time. LACAN uses simple models to describe the elementary physical processes: evaporation, vapour expansion, interaction between photons and atoms, ion extraction etc ... These simple models are derived from refined modeling codes or are empirical. As an example the optimization of the separative work of an uranium facility is discussed

  6. The study of separation of crystal Fe and morphology for FeB nanoparticle: Molecular dynamics simulation

    Directory of Open Access Journals (Sweden)

    Kien Pham Huu

    2017-04-01

    Full Text Available The separation of Fe crystal from amorphous nanoparticle (NP has been studied using molecular dynamics simulation. The simulation shows that the NP is crystallized through three stages. In the first stage NP undergoes the relaxation which results in forming nucleation regions where the atomic arrangement is similar to the distorted crystalline lattice. During the first stage the nuclei are unstable and dissolve for short times. In the second stage the stable crystal clusters have been created and new nuclei are formed mainly in the boundary region of crystal cluster. The stable crystal cluster grows in the direction to cover the core and then spreads out to the surface of NP. For the third stage the crystal cluster grows slightly with times. Further study concerns the different morphologies of NP. We found that the crystalline NP comprises a Fe crystalline grain with defects and separate clusters of Am-atom. Comparing to the amorphous NP, the structure organization of crystalline NP is more complicated and cannot be described by the simple shell/core model.

  7. An optimal two-stage phase II design utilizing complete and partial response information separately.

    Science.gov (United States)

    Panageas, Katherine S; Smith, Alex; Gönen, Mithat; Chapman, Paul B

    2002-08-01

    Phase II clinical trials in oncology are performed to evaluate the therapeutic efficacy of a new treatment regimen. A common measure of efficacy for these trials is the proportion of patients who obtain a response measured by tumor shrinkage. It is standard practice to classify this response into the following categories: (1) complete response (CR); (2) partial response (PR); (3) stable disease; and (4) progression of disease. Tumor response is then treated as a binary variable whereby patients who achieve either a CR or a PR are considered responders and all others nonresponders. A two-stage design that allows for early termination of the trial if the treatment shows little efficacy such as Gehan or Simon gives equal weight to a CR and a PR. However, a CR, defined as complete disappearance of the tumor, is more likely than a PR to signal an important antitumor effect and result in a survival advantage. We argue that CRs and PRs should be considered separately, and hence we propose a two-stage design with a multilevel endpoint (i.e., CR, PR, and nonresponders). This design is an extension of Simon's optimal two-stage design and is based on a trinomial model. For most scenarios the proposed design results in an improvement in expected sample size compared to Simon's optimal design. Design optimization was performed by a direct search based on enumerating exact trinomial probabilities. Sample size tables are provided for parameter sets commonly used in the oncologic setting. Software is available by contacting the authors.

  8. Effect of applied strain on phase separation of Fe-28 at.% Cr alloy: 3D phase-field simulation

    Science.gov (United States)

    Zhu, Lihui; Li, Yongsheng; Liu, Chengwei; Chen, Shi; Shi, Shujing; Jin, Shengshun

    2018-04-01

    A quantitative simulation of the separation of the α‧ phase in Fe-28 at.% Cr alloy under the effects of applied strain is performed by utilizing a three-dimensional phase-field model. The elongation of the Cr-enriched α‧ phase becomes obvious with the influence of applied uniaxial strain for the phase separation transforms from spinodal decomposition of 700 K to nucleation and growth of 773 K. The applied strain shows a significant influence on the early stage phase separation, and the influence is enlarged with the elevated temperature. The steady-state coarsening with the mechanism of spinodal decomposition is substantially affected by the applied strain for low-temperature aging, while the influence is reduced as the temperature increases and as the phase separation mechanism changes to nucleation and growth. The peak value of particle size distribution decreases, and the PSD for 773 K becomes more widely influenced by the applied strain. The simulation results of separation of the Cr-enriched α‧ phase with the applied strain provide a further understanding of the strain effect on the phase separation of Fe-Cr alloys from the metastable region to spinodal regions.

  9. Data supporting the validation of a simulation model for multi-component gas separation in polymeric membranes

    Directory of Open Access Journals (Sweden)

    Lorena Giordano

    2016-12-01

    The data were obtained using a model for simulating gas separation, described in the research article entitled “Interplay of inlet temperature and humidity on energy penalty for CO2 post-combustion capture: rigorous analysis and simulation of a single stage gas permeation process” (L. Giordano, D. Roizard, R. Bounaceur, E. Favre, 2016 [1]. The data were used to validate the model by comparison with literature results. Considering a membrane system based on feed compression only, data from the model proposed and that from literature were compared with respect to the molar composition of permeate stream, the membrane area and specific energy requirement, varying the feed pressure and the CO2 separation degree.

  10. A multi-stage oil-water-separating process design for the sea oil spill recovery robot

    Science.gov (United States)

    Zhang, Min-ge; Wu, Jian-guo; Lin, Xinhua; Wang, Xiao-ming

    2018-03-01

    Oil spill have the most common pollution to the marine ecological environment. In the late stage of physical method recovery, because of the thin oil and the strong sea breeze, the recovery vessels has low efficiency and high energy consumption. This paper develops a multi-stage oil-water-separating process carried by the sea oil spill recovery robot in severe conditions. This design consists of three separation process, among which both the first and third process adopt corrugated sheets horizontal oil-water separator, while the second is hydraulic rotary breaker. This design also equiptment with rectifier and cyclone separator and other important components. This process has high flexibility and high recovery efficiency. The implement effect is significant.

  11. Numerical simulation and structural optimization of the inclined oil/water separator.

    Directory of Open Access Journals (Sweden)

    Liqiong Chen

    Full Text Available Improving the separation efficiency of the inclined oil/water separator, a new type of gravity separation equipment, is of great importance. In order to obtain a comprehensive understanding of the internal flow field of the separation process of oil and water within this separator, a numerical simulation based on Euler multiphase flow analysis and the realizable k-ε two equation turbulence model was executed using Fluent software. The optimal value ranges of the separator's various structural parameters used in the numerical simulation were selected through orthogonal array experiments. A field experiment on the separator was conducted with optimized structural parameters in order to validate the reliability of the numerical simulation results. The research results indicated that the horizontal position of the dispenser, the hole number, and the diameter had significant effects on the oil/water separation efficiency, and that the longitudinal position of the dispenser and the position of the weir plate had insignificant effects on the oil/water separation efficiency. The optimal structural parameters obtained through the orthogonal array experiments resulted in an oil/water separation efficiency of up to 95%, which was 4.996% greater than that realized by the original structural parameters.

  12. Separation of technetium from nuclear waste stream simulants. Final report

    International Nuclear Information System (INIS)

    Strauss, S.H.

    1995-01-01

    The author studied liquid anion exchangers, such as Aliquat-336 nitrate, various pyridinium nitrates, and related salts, so that they may be applied toward a specific process for extracting (partitioning) and recovering 99 TcO 4 - from nuclear waste streams. Many of the waste streams are caustic and contain a variety of other ions. For this reason, the author studied waste stream simulants that are caustic and contain appropriate concentrations of selected, relevant ions. Methods of measuring the performance of the exchangers and extractant systems included contact experiments. Batch contact experiments were used to determine the forward and reverse extraction parameters as a function of temperature, contact time, phase ratio, concentration, solvent (diluent), and other physical properties. They were also used for stability and competition studies. Specifically, the author investigated the solvent extraction behavior of salts of perrhenate (ReO 4 - ), a stable (non-radioactive) chemical surrogate for 99 TcO 4 - . Results are discussed for alternate organic solvents; metalloporphyrins, ferrocenes, and N-cetyl pyridium nitrate as alternate extractant salts; electroactive polymers; and recovery of ReO 4 - and TcO 4 -

  13. Separation of technetium from nuclear waste stream simulants. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, S.H. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Chemistry

    1995-09-11

    The author studied liquid anion exchangers, such as Aliquat-336 nitrate, various pyridinium nitrates, and related salts, so that they may be applied toward a specific process for extracting (partitioning) and recovering {sup 99}TcO{sub 4}{sup {minus}} from nuclear waste streams. Many of the waste streams are caustic and contain a variety of other ions. For this reason, the author studied waste stream simulants that are caustic and contain appropriate concentrations of selected, relevant ions. Methods of measuring the performance of the exchangers and extractant systems included contact experiments. Batch contact experiments were used to determine the forward and reverse extraction parameters as a function of temperature, contact time, phase ratio, concentration, solvent (diluent), and other physical properties. They were also used for stability and competition studies. Specifically, the author investigated the solvent extraction behavior of salts of perrhenate (ReO{sub 4}{sup {minus}}), a stable (non-radioactive) chemical surrogate for {sup 99}TcO{sub 4}{sup {minus}}. Results are discussed for alternate organic solvents; metalloporphyrins, ferrocenes, and N-cetyl pyridium nitrate as alternate extractant salts; electroactive polymers; and recovery of ReO{sub 4}{sup {minus}} and TcO{sub 4}{sup {minus}}.

  14. Efficient performance simulation of class D amplifier output stages

    DEFF Research Database (Denmark)

    Nyboe, Flemming; Risbo, Lars; Andreani, Pietro

    2005-01-01

    Straightforward simulation of amplifier distortion involves transient simulation of operation on a sine wave input signal, and a subsequent FFT of the output voltage. This approach is very slow on class D amplifiers, since the switching behavior forces simulation time steps that are many orders...... of magnitude smaller than the duration of one period of an audio sine wave. This work presents a method of simulating the amplifier transfer characteristic using a minimum amount of simulation time, and then deriving THD from the results....

  15. Building performance simulation in the early design stage: An introduction to integrated dynamic models

    DEFF Research Database (Denmark)

    Negendahl, Kristoffer

    2015-01-01

    Designing with building performance simulation feedback in the early design stage has existed since the early days of computational modeling. However, as a consequence of a fragmented building industry building performance simulations (BPSs) in the early design stage are closely related to who is...

  16. Signatures of natural selection between life cycle stages separated by metamorphosis in European eel

    DEFF Research Database (Denmark)

    Pujolar, J.M.; Jacobsen, M.W.; Bekkevold, Dorte

    2015-01-01

    Species showing complex life cycles provide excellent opportunities to study the genetic associations between life cycle stages, as selective pressures may differ before and after metamorphosis. The European eel presents a complex life cycle with two metamorphoses, a first metamorphosis from larvae...... into glass eels (juvenile stage) and a second metamorphosis into silver eels (adult stage). We tested the hypothesis that different genes and gene pathways will be under selection at different life stages when comparing the genetic associations between glass eels and silver eels. Results: We used two sets...... supports the adaptive decoupling hypothesis for the benefits of metamorphosis. Partitioning the life cycle into discrete morphological phases may be overall beneficial since it allows the different life stages to respond independently to their unique selection pressures. This might translate into a more...

  17. CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

    Directory of Open Access Journals (Sweden)

    K. Rambabu

    2014-01-01

    Full Text Available A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

  18. Orthotropic node-separation finite element method for composite laminate in hypervelocity impact simulation

    Science.gov (United States)

    Zhang, Xiaotian; Liu, Tao; Qiu, Xinming

    2017-11-01

    This paper reports a finite element modeling approach to simulate the hypervelocity impact (HVI) response of composite laminate. Node-separation finite element (NSFE) method based on scalar-element-fracture technique for isotropic material in HVI simulation has been presented in the previous study. To extend NSFE to composite materials, an orthotropic node-separation finite element (ONSFE) method is developed. This approach employs an orthotropic continuum material model and a corresponding orthotropic-element-fracture technique to represent the HVI behavior/damage of composite laminate. A series of HVI simulations are conducted and the developed ONSFE method is validated by comparing with the experimental data. The simulation results show that ONSFE can successfully capture the HVI phenomena of composite laminate, such as the orthotropic property, nonlinear shock response, perforation, fiber breakage and delamination. Finally, a HVI event of Whipple shield is simulated and the computational capability of ONSFE for predicting the damage state of the composite bumper is further evaluated.

  19. A new numerical approach for a detailed multicomponent gas separation membrane model and AspenPlus simulation

    Energy Technology Data Exchange (ETDEWEB)

    Murad Chowdhury, M.H.; Feng, X.; Douglas, P.; Croiset, E. [Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2005-07-01

    A new numerical solution approach for a widely accepted model developed earlier by Pan [1] for multicomponent gas separation by high-flux asymmetric membranes is presented. The advantage of the new technique is that it can easily be incorporated into commercial process simulators such as AspenPlus trademark [2] as a user-model for an overall membrane process study and for the design and simulation of hybrid processes (i.e., membrane plus chemical absorption or membrane plus physical absorption). The proposed technique does not require initial estimates of the pressure, flow and concentration profiles inside the fiber as does in Pan's original approach, thus allowing faster execution of the model equations. The numerical solution was formulated as an initial value problem (IVP). Either Adams-Moulton's or Gear's backward differentiation formulas (BDF) method was used for solving the non-linear differential equations, and a modified Powell hybrid algorithm with a finite-difference approximation of the Jacobian was used to solve the non-linear algebraic equations. The model predictions were validated with experimental data reported in the literature for different types of membrane gas separation systems with or without purge streams. The robustness of the new numerical technique was also tested by simulating the stiff type of problems such as air dehydration. This demonstrates the potential of the new solution technique to handle different membrane systems conveniently. As an illustration, a multi-stage membrane plant with recycle and purge streams has been designed and simulated for CO{sub 2} capture from a 500 MW power plant flue gas as a first step to build hybrid processes and also to make an economic comparison among different existing separation technologies available for CO{sub 2} separation from flue gas. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  20. Monte Carlo simulations of the phase separation of a copolymer blend in a thin film

    KAUST Repository

    Wang, Zhexiao

    2014-12-11

    Monte Carlo simulations were carried out to study the phase separation of a copolymer blend comprising an alternating copolymer and/or block copolymer in a thin film, and a phase diagram was constructed with a series of composed recipes. The effects of composition and segregation strength on phase separation were discussed in detail. The chain conformation of the block copolymer and alternating copolymer were investigated with changes of the segregation strength. Our simulations revealed that the segment distribution along the copolymer chain and the segregation strength between coarse-grained beads are two important parameters controlling phase separation and chain conformation in thin films of a copolymer blend. A well-controlled phase separation in the copolymer blend can be used to fabricate novel nanostructures.

  1. Molecular dynamics simulations of phase separation in the presence of surfactants

    DEFF Research Database (Denmark)

    Laradji, Mohamed; Mouritsen, Ole G.; Toxvaerd, Søren

    1994-01-01

    The dynamics of phase separation in two-dimensional binary mixtures diluted by surfactants is studied by means of molecular dynamics simulations. In contrast to pure binary systems, characterized by an algebraic time dependence of the average domain size, we find that systems containing surfactants...... exhibit nonalgebraic, slow dynamics. The average domain size eventually saturates at a value inversely proportional to the surfactant concentration. We also find that phase separation in systems with different surfactant concentrations follow a crossover scaling form. Finally, although these systems do...... not fully phase separate, we observe a dynamical scaling which is independent of the surfactant concentration. The results of these simulations are in general in agreement with previous Langevin simulations [Laradji, Guo, Grant, and Zuckermann, J. Phys. A 44, L629 (1991)] and a theory of Ostwald ripening...

  2. Morphological Simulation of Phase Separation Coupled Oscillation Shear and Varying Temperature Fields

    Science.gov (United States)

    Wang, Heping; Li, Xiaoguang; Lin, Kejun; Geng, Xingguo

    2018-02-01

    This paper explores the effect of the shear frequency and Prandtl number (Pr) on the procedure and pattern formation of phase separation in symmetric and asymmetric systems. For the symmetric system, the periodic shear significantly prolongs the spinodal decomposition stage and enlarges the separated domain in domain growth stage. By adjusting the Pr and shear frequency, the number and orientation of separated steady layer structures can be controlled during domain stretch stage. The numerical results indicate that the increase in Pr and decrease in the shear frequency can significantly increase in the layer number of the lamellar structure, which relates to the decrease in domain size. Furthermore, the lamellar orientation parallel to the shear direction is altered into that perpendicular to the shear direction by further increasing the shear frequency, and also similar results for larger systems. For asymmetric system, the quantitative analysis shows that the decrease in the shear frequency enlarges the size of separated minority phases. These numerical results provide guidance for setting the optimum condition for the phase separation under periodic shear and slow cooling.

  3. Checklist usage decreases critical task omissions when training residents to separate from simulated cardiopulmonary bypass.

    Science.gov (United States)

    Petrik, Edward W; Ho, Dennis; Elahi, Maqsood; Ball, Timothy R; Hofkamp, Michael P; Wehbe-Janek, Hania; Culp, William C; Villamaria, Frank J

    2014-12-01

    Separation from cardiopulmonary bypass (CPB) requires multiple preparatory steps, during which mistakes, omissions, and human errors may occur. Checklists have been used extensively in aviation to improve performance of complex, multistep tasks. The aim of this study was to (1) develop a checklist using a modified Delphi process to identify essential steps necessary to prepare for separation from CPB, and (2) compare the frequency of completed items with and without the use of a checklist in simulation. It was hypothesized that the use of a checklist would reduce the number of omissions. High-fidelity simulation study. University-affiliated tertiary care facility. Seven cardiac anesthesiologists created a checklist using a modified Delphi process. Ten residents participated in 4 scenarios separating from CPB in simulation. Each scenario was performed first without a checklist and then again with a checklist. An observer graded participants' performance. A pre-separation checklist containing 9 tasks was created using the Delphi process. Without using this checklist, 4 tasks were completed in at least 75% of scenarios, and 8 tasks were completed at least 75% of the time when using the checklist. There was a significant improvement in completion of 5 of the 9 items (pchecklist of steps in preparing to separate from CPB. Using this checklist during simulation resulted in increased frequency of completing designated tasks in comparison to relying on memory alone. Checklists may reduce omission errors during complex periods of anesthesiologists' perioperative workflow. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. The Separation of Blood Components Using Standing Surface Acoustic Waves (SSAWs Microfluidic Devices: Analysis and Simulation

    Directory of Open Access Journals (Sweden)

    Ahmed M. Soliman

    2017-03-01

    Full Text Available The separation of blood components (WBCs, RBCs, and platelets is important for medical applications. Recently, standing surface acoustic wave (SSAW microfluidic devices are used for the separation of particles. In this paper, the design analysis of SSAW microfluidics is presented. Also, the analysis of SSAW force with Rayleigh angle effect and its attenuation in liquid-loaded substrate, viscous drag force, hydrodynamic force, and diffusion force are explained and analyzed. The analyses are provided for selecting the piezoelectric material, width of the main microchannel, working area of SAW, wavelength, minimum input power required for the separation process, and widths of outlet collecting microchannels. The design analysis of SSAW microfluidics is provided for determining the minimum input power required for the separation process with appropriated the displacement contrast of the particles.The analyses are applied for simulation the separation of blood components. The piezoelectric material, width of the main microchannel, working area of SAW, wavelength, and minimum input power required for the separation process are selected as LiNbO3, 120 μm, 1.08 mm2, 300 μm, 371 mW. The results are compared to other published results. The results of these simulations achieve minimum power consumption, less complicated setup, and high collecting efficiency. All simulation programs are built by MATLAB.

  5. Reactive molecular dynamic simulations on the gas separation performance of porous graphene membrane.

    Science.gov (United States)

    Esfandiarpoor, Somaye; Fazli, Mostafa; Ganji, Masoud Darvish

    2017-11-29

    The separation of gases molecules with similar diameter and shape is an important area of research. For example, the major challenge to set up sweeping carbon dioxide capture and storage (CCS) in power plants is the energy requisite to separate the CO 2 from flue gas. Porous graphene has been proposed as superior material for highly selective membranes for gas separation. Here we design some models of porous graphene with different sizes and shape as well as employ double layers porous graphene for efficient CO 2 /H 2 separation. The selectivity and permeability of gas molecules through various nanopores were investigated by using the reactive molecular dynamics simulation which considers the bond forming/breaking mechanism for all atoms. Furthermore, it uses a geometry-dependent charge calculation scheme that accounts appropriately for polarization effect which can play an important role in interacting systems. It was found that H-modified porous graphene membrane with pore diameter (short side) of about 3.75 Å has excellent selectivity for CO 2 /H 2 separation. The mechanism of gas penetration through the sub-nanometer pore was presented for the first time. The accuracy of MD simulation results validated by valuable DFT method. The present findings show that reactive MD simulation can propose an economical means of separating gases mixture.

  6. Dynamic models of staged gasification processes. Documentation of gasification simulator; Dynamiske modeller a f trinopdelte forgasningsprocesser. Dokumentation til forgasser simulator

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-02-15

    In connection with the ERP project 'Dynamic modelling of staged gasification processes' a gasification simulator has been constructed. The simulator consists of: a mathematical model of the gasification process developed at Technical University of Denmark, a user interface programme, IGSS, and a communication interface between the two programmes. (BA)

  7. Automated synthesis of photovoltaic-quality colloidal quantum dots using separate nucleation and growth stages

    KAUST Repository

    Pan, Jun

    2013-11-26

    As colloidal quantum dot (CQD) optoelectronic devices continue to improve, interest grows in the scaled-up and automated synthesis of high-quality materials. Unfortunately, all reports of record-performance CQD photovoltaics have been based on small-scale batch syntheses. Here we report a strategy for flow reactor synthesis of PbS CQDs and prove that it leads to solar cells having performance similar to that of comparable batch-synthesized nanoparticles. Specifically, we find that, only when using a dual-temperature-stage flow reactor synthesis reported herein, are the CQDs of sufficient quality to achieve high performance. We use a kinetic model to explain and optimize the nucleation and growth processes in the reactor. Compared to conventional single-stage flow-synthesized CQDs, we achieve superior quality nanocrystals via the optimized dual-stage reactor, with high photoluminescence quantum yield (50%) and narrow full width-half-maximum. The dual-stage flow reactor approach, with its versatility and rapid screening of multiple parameters, combined with its efficient materials utilization, offers an attractive path to automated synthesis of CQDs for photovoltaics and, more broadly, active optoelectronics. © 2013 American Chemical Society.

  8. Signatures of natural selection between life cycle stages separated by metamorphosis in European eel.

    Science.gov (United States)

    Pujolar, J M; Jacobsen, M W; Bekkevold, D; Lobón-Cervià, J; Jónsson, B; Bernatchez, L; Hansen, M M

    2015-08-13

    Species showing complex life cycles provide excellent opportunities to study the genetic associations between life cycle stages, as selective pressures may differ before and after metamorphosis. The European eel presents a complex life cycle with two metamorphoses, a first metamorphosis from larvae into glass eels (juvenile stage) and a second metamorphosis into silver eels (adult stage). We tested the hypothesis that different genes and gene pathways will be under selection at different life stages when comparing the genetic associations between glass eels and silver eels. We used two sets of markers to test for selection: first, we genotyped individuals using a panel of 80 coding-gene single nucleotide polymorphisms (SNPs) developed in American eel; second, we investigated selection at the genome level using a total of 153,423 RAD-sequencing generated SNPs widely distributed across the genome. Using the RAD approach, outlier tests identified a total of 2413 (1.57%) potentially selected SNPs. Functional annotation analysis identified signal transduction pathways as the most over-represented group of genes, including MAPK/Erk signalling, calcium signalling and GnRH (gonadotropin-releasing hormone) signalling. Many of the over-represented pathways were related to growth, while others could result from the different conditions that eels inhabit during their life cycle. The observation of different genes and gene pathways under selection when comparing glass eels vs. silver eels supports the adaptive decoupling hypothesis for the benefits of metamorphosis. Partitioning the life cycle into discrete morphological phases may be overall beneficial since it allows the different life stages to respond independently to their unique selection pressures. This might translate into a more effective use of food and niche resources and/or performance of phase-specific tasks (e.g. feeding in the case of glass eels, migrating and reproducing in the case of silver eels).

  9. Simulated Moving Bed Chromatography: Separation and Recovery of Sugars and Ionic Liquid from Biomass Hydrolysates

    Science.gov (United States)

    Caes, Benjamin R.; Van Oosbree, Thomas R.; Lu, Fachuang; Ralph, John; Maravelias, Christos T.

    2015-01-01

    Simulated moving bed chromatography, a continuous separation method, enables the nearly quantitative recovery of sugar products and ionic liquid solvent from chemical hydrolysates of biomass. The ensuing sugars support microbial growth, and the residual lignin from the process is intact. PMID:23939991

  10. Concentration gradient driven molecular dynamics: a new method for simulations of membrane permeation and separation.

    Science.gov (United States)

    Ozcan, Aydin; Perego, Claudio; Salvalaglio, Matteo; Parrinello, Michele; Yazaydin, Ozgur

    2017-05-01

    In this study, we introduce a new non-equilibrium molecular dynamics simulation method to perform simulations of concentration driven membrane permeation processes. The methodology is based on the application of a non-conservative bias force controlling the concentration of species at the inlet and outlet of a membrane. We demonstrate our method for pure methane, ethane and ethylene permeation and for ethane/ethylene separation through a flexible ZIF-8 membrane. Results show that a stationary concentration gradient is maintained across the membrane, realistically simulating an out-of-equilibrium diffusive process, and the computed permeabilities and selectivity are in good agreement with experimental results.

  11. An experimentally validated simulation model for a four-stage spray dryer

    DEFF Research Database (Denmark)

    Petersen, Lars Norbert; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

    2017-01-01

    is divided into four consecutive stages: a primary spray drying stage, two heated fluid bed stages, and a cooling fluid bed stage. Each of these stages in the model is assumed ideally mixed and the dynamics are described by mass- and energy balances. These balance equations are coupled with constitutive......In this paper, we develop a dynamic model of an industrial type medium size four-stage spray dryer. The purpose of the model is to enable simulations of the spray dryer at different operating points, such that the model facilitates development and comparison of control strategies. The dryer...... mathematical model is an index-1 differential algebraic equation (DAE) model with 12 states, 9 inputs, 8 disturbances, and 30 parameters. The parameters in the model are identified from well-excited experimental data obtained from the industrialtype spray dryer. The simulated outputs ofthe model are validated...

  12. Numerical simulations of gas-liquid-solid flows in a hydrocyclone separator

    Energy Technology Data Exchange (ETDEWEB)

    Mousavian, S.M.; Najafi, A.F. [Power and Water University of Technology, School of Energy Engineering, P.O. Box: 16765-1719, Tehran (Iran)

    2009-05-15

    The flow behavior in hydrocyclones is quite complex. In this study, the computational fluid dynamics (CFD) method was used to simulate the flow fields inside a hydrocyclone in order to investigate its separation efficiency. In the computational fluid dynamics study of hydrocyclones, the air-core dimension is a key to predicting the mass split between the underflow and overflow. In turn, the mass split influences the prediction of the size classification curve. Three models, the k-{epsilon} model, the Reynolds stress model (RSM) without considering the air-core, and the Reynolds stress turbulence model with the volume of fluid (VOF) multiphase model for simulating the air-core, were compared in terms of their predictions of velocity, axial and tangential velocity distributions, and separation proportion. The RSM with air-core simulation model, since it reproduces some detailed features of the turbulence and multiphase, clearly predicted the experimental data more closely than did the other two models. (orig.)

  13. Beam Dynamics Simulations of the REX-ISOLDE A/q-separator

    CERN Document Server

    Fraser, M A; Wenander, F

    2014-01-01

    The REX-ISOLDE A=q-separator selects the radioactive species of interest from the background of residual gas ions coming from the EBIS ion source. In the context of the HIE-ISOLDE upgrade, including the implementation of a multi-harmonic buncher and an upgraded EBIS, the separator and the beam line between the EBIS and RFQ, which we will call the Low Energy Beam Transfer (LEBT) line, has been simulated by tracking particles through the field maps of each active element using the TRACK [4] code. The simulations were benchmarked with a COSY-1 model that was improved to take into account the fringe fields of the electrostatic quadrupoles, electrostatic deflector and magnetic bender; the model can be used to tune and optimise the separator with higher-order effects taken into account. In this note the beam dynamics simulations are documented and the transverse and longitudinal acceptance of the separator line studied to provide design constraints for the EBIS upgrade.

  14. Molecular Simulation Insights on Xe/Kr Separation in a Set of Nanoporous Crystalline Membranes.

    Science.gov (United States)

    Anderson, Ryther; Schweitzer, Benjamin; Wu, Ting; Carreon, Moises A; Gómez-Gualdrón, Diego A

    2018-01-10

    Separation of xenon and krypton is highly relevant to several applications such as spent nuclear fuel processing. Molecular simulation has been extensively used to understand the Kr/Xe separation performance of nanoporous materials for adsorption-based technologies but less frequently for membrane-based technologies. Motivated by recent experimental reports on krypton-selective membranes, herein, we present grand canonical Monte Carlo and biased molecular dynamics simulations (using adaptive biasing force) to elucidate the nature of adsorption- and diffusion-based Kr/Xe separation mechanisms in a set of nanoporous materials: SAPO-34, ZIF-8, UiO-66, and IRMOF-1. Xenon is found to preferentially adsorb on all materials, but diffusion selectivity for krypton is found to dominate the overall membrane separation selectivity. To increase adsorption selectivity for krypton, large pore cages are found to be desirable. To increase diffusion selectivity for krypton, stiff pore windows with a diameter smaller than xenon (but larger than krypton) are found to be desirable. No perfect molecular sieving was found, but the relatively rigid SAPO-34 was more effective at excluding xenon than the more flexible ZIF-8. Indeed, during xenon "window crossing," the SAPO-34 window opened to only 3.8 Å, while the ZIF-8 window opened to 4.1 Å, resulting in a lower free energy "diffusion" barrier for xenon in ZIF-8. Therefore, an ideal membrane material for Kr/Xe separation should be rigid and have large pore cages and small pore windows. Temperature was found to have opposite effects on adsorption and diffusion selectivity, but because of the dominance of diffusion selectivity, our simulations indicate that it is preferable to operate membranes for Kr/Xe separation at lower temperatures than at higher ones.

  15. Separating stages of arithmetic verification: An ERP study with a novel paradigm.

    Science.gov (United States)

    Avancini, Chiara; Soltész, Fruzsina; Szűcs, Dénes

    2015-08-01

    In studies of arithmetic verification, participants typically encounter two operands and they carry out an operation on these (e.g. adding them). Operands are followed by a proposed answer and participants decide whether this answer is correct or incorrect. However, interpretation of results is difficult because multiple parallel, temporally overlapping numerical and non-numerical processes of the human brain may contribute to task execution. In order to overcome this problem here we used a novel paradigm specifically designed to tease apart the overlapping cognitive processes active during arithmetic verification. Specifically, we aimed to separate effects related to detection of arithmetic correctness, detection of the violation of strategic expectations, detection of physical stimulus properties mismatch and numerical magnitude comparison (numerical distance effects). Arithmetic correctness, physical stimulus properties and magnitude information were not task-relevant properties of the stimuli. We distinguished between a series of temporally highly overlapping cognitive processes which in turn elicited overlapping ERP effects with distinct scalp topographies. We suggest that arithmetic verification relies on two major temporal phases which include parallel running processes. Our paradigm offers a new method for investigating specific arithmetic verification processes in detail. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Modeling and simulation of membrane separation process using computational fluid dynamics

    Directory of Open Access Journals (Sweden)

    Kambiz Tahvildari

    2016-01-01

    Full Text Available Separation of CO2 from air was simulated in this work. The considered process for removal of CO2 was a hollow-fiber membrane contactor and an aqueous solution of 2-amino-2-metyl-1-propanol (AMP as absorbent. The model was developed based on mass transfer as well as chemical reaction for CO2 and solvent in the contactor. The equations of model were solved using finite element method. Simulation results were compared with experimental data, and good agreement was observed. The results revealed that increasing solvent velocity enhances removal of CO2 in the hollow-fiber membrane contactor. Moreover, it was found that counter-current process mode is more favorable to achieve the highest separation efficiency.

  17. Simulation of phase separation with temperature-dependent viscosity using lattice Boltzmann method.

    Science.gov (United States)

    Wang, Heping; Zang, Duyang; Li, Xiaoguang; Geng, Xingguo

    2017-12-27

    This paper presents an exploration of the phase separation behavior and pattern formation in a binary fluid with temperature-dependent viscosity via a coupled lattice Boltzmann method (LBM). By introducing a viscosity-temperature relation into the LBM, the coupling effects of the viscosity-temperature coefficient [Formula: see text] , initial viscosity [Formula: see text] and thermal diffusion coefficient [Formula: see text] , on the phase separation were successfully described. The calculated results indicated that an increase in initial viscosity and viscosity-temperature coefficient, or a decrease in the thermal diffusion coefficient, can lead to the orientation of isotropic growth fronts over a wide range of viscosity. The results showed that droplet-type phase structures and lamellar phase structures with domain orientation parallel or perpendicular to the walls can be obtained in equilibrium by controlling the initial viscosity, thermal diffusivity, and the viscosity-temperature coefficient. Furthermore, the dataset was rearranged for growth kinetics of domain growth and thermal diffusion fronts in a plot by the spherically averaged structure factor and the ratio of separated and continuous phases. The analysis revealed two different temporal regimes: spinodal decomposition and domain growth stages, which further quantified the coupled effects of temperature and viscosity on the evolution of temperature-dependent phase separation. These numerical results provide guidance for setting optimum temperature ranges to obtain expected phase separation structures for systems with temperature-dependent viscosity.

  18. CFD simulation of inlet design effect on deoiling hydrocyclone separation efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Noroozi, S.; Hashemabadi, S.H. [Computational Fluid Dynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of)

    2009-12-15

    An Eulerian-Eulerian three-dimensional CFD model was developed to study the effect of different inlet designs on deoiling hydrocyclone separation efficiency. Reynolds averaged Navier Stokes and continuity equations were applied to solve steady turbulent flow through the cyclone with the Reynolds stress model. In addition, the modified drag correlation for liquid-liquid emulsion with respect to the Reynolds number range and viscosity ratio of two phases was used and the simulation results were compared with those predicted by the Schiller-Naumann correlation. Pressure profile, tangential and axial velocities and separation efficiency of the deoiling hydrocyclone were calculated for four different inlet designs and compared with the standard design. The simulation results for the standard design demonstrate an acceptable agreement with reported experimental data. The results show that all new four inlet designs offer higher efficiencies compared to the standard design. The difference between the efficiency of the LLHC, of the new inlets and the standard design can be improved by increasing the inlet velocity. Furthermore, the simulations show that the separation efficiency can be improved by about 10 % when using a helical form of inlet. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Accelerated Monte Carlo simulation on the chemical stage in water radiolysis using GPU

    Science.gov (United States)

    Tian, Zhen; Jiang, Steve B.; Jia, Xun

    2017-04-01

    The accurate simulation of water radiolysis is an important step to understand the mechanisms of radiobiology and quantitatively test some hypotheses regarding radiobiological effects. However, the simulation of water radiolysis is highly time consuming, taking hours or even days to be completed by a conventional CPU processor. This time limitation hinders cell-level simulations for a number of research studies. We recently initiated efforts to develop gMicroMC, a GPU-based fast microscopic MC simulation package for water radiolysis. The first step of this project focused on accelerating the simulation of the chemical stage, the most time consuming stage in the entire water radiolysis process. A GPU-friendly parallelization strategy was designed to address the highly correlated many-body simulation problem caused by the mutual competitive chemical reactions between the radiolytic molecules. Two cases were tested, using a 750 keV electron and a 5 MeV proton incident in pure water, respectively. The time-dependent yields of all the radiolytic species during the chemical stage were used to evaluate the accuracy of the simulation. The relative differences between our simulation and the Geant4-DNA simulation were on average 5.3% and 4.4% for the two cases. Our package, executed on an Nvidia Titan black GPU card, successfully completed the chemical stage simulation of the two cases within 599.2 s and 489.0 s. As compared with Geant4-DNA that was executed on an Intel i7-5500U CPU processor and needed 28.6 h and 26.8 h for the two cases using a single CPU core, our package achieved a speed-up factor of 171.1-197.2.

  20. Numerical simulation of gas-solid two-phase flow in U-beam separator

    International Nuclear Information System (INIS)

    Zhou, X Y; Chen, X P; Dou, H S; Zhang, H Z; Ruan, J M

    2015-01-01

    Numerical simulation is carried out for gas-solid two-phase flow in a U-beam separator. In this study, the U-beam is altered with the inlet fins in order to improve the performance of the separator. The inlet fin angle of the separator are 30°, 35°, 40°, 45°, 50°, 55 ° and 60°. The governing equations are the Reynolds-Averaged Navier-Stokes equation with the standard k-ε model and the discrete phase model (DPM) describing the discrete two - phase flow as well as stochastic tracking model. Results show that the pressure drop deviation with fins is within 3% from those without fins. It is found that there is a maximum separation efficiency at the fin angle of 35°. Fin induces generation of a stagnation region which could collect particles and lead to change of vortical structures. The fin induced flow also causes the turbulent intensity inside the baffle to decrease to facilitate separation

  1. Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures.

    Science.gov (United States)

    Altintas, Cigdem; Keskin, Seda

    2017-11-11

    Metal organic framework (MOF) membranes have been widely investigated for gas separation applications. Several MOFs have been recently examined for selective separation of C 2 H 6 . Considering the large number of available MOFs, it is not possible to fabricate and test the C 2 H 6 separation performance of every single MOF membrane using purely experimental methods. In this study, we used molecular simulations to assess the membrane-based C 2 H 6 /C 2 H 4 and C 2 H 6 /CH 4 separation performances of 175 different MOF structures. This is the largest number of MOF membranes studied to date for C 2 H 6 separation. We computed adsorption selectivity, diffusion selectivity, membrane selectivity and gas permeability of MOFs for C 2 H 6 /C 2 H 4 and C 2 H 6 /CH 4 mixtures. Our results show that a significant number of MOF membranes are C 2 H 6 selective for C 2 H 6 /C 2 H 4 separation in contrast to traditional nanoporous materials. Selectivity and permeability of MOF membranes were compared with other membrane materials, such as polymers, zeolites, and carbon molecular sieves. Several MOFs were identified to exceed the upper bound established for polymeric membranes and many MOF membranes exhibited higher gas permeabilities than zeolites and carbon molecular sieves. Examining the structure-performance relations of MOF membranes revealed that MOFs with cavity diameters between 6 and 9 Å, porosities lower than 0.50, and surface areas between 500-1000 m 2 g -1 have high C 2 H 6 selectivities. The results of this study will be useful to guide the experiments to the most promising MOF membranes for efficient separation of C 2 H 6 and to accelerate the development of new MOFs with high C 2 H 6 selectivities.

  2. Transient response simulation of gas separation membrane module for an atmosphere detritiation system

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, Takahiko, E-mail: t-sugiyama@nucl.nagoya-u.ac.jp [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Tanaka, Masahiro [National Institute for Fusion Science, Oroshi-cho 322-6, Toki-shi, Gifu 509-5292 (Japan); Munakata, Kenzo [Akita University, Tegata Gakuen-cho 1-1, Akita-shi, Akita 010-8502 (Japan); Yamamoto, Ichiro [Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan)

    2012-08-15

    Transient response of a gas separation membrane module for the atmosphere detritiation system was numerically simulated with a mass transfer model. The module contains thousands of hollow fiber type polyimide membranes. The simulation model took into account permeation of water vapor through the dense layer of the membrane, diffusive transfer through the porous support layer and adsorption/desorption of water vapor into the matrix of the porous layer. The slow responses of the water vapor concentration in the retentate and the permeation rate were well reproduced by the present simulation, and transient changes in a follow fiber membrane were investigated in detail. The inventory and the mean residence time of water vapor at 303 K were estimated for the commercial membrane module (UMS-B2, Ube industries, Ltd.) as 5.7 Multiplication-Sign 10{sup -3} mol and 380 s, respectively.

  3. Numerical simulation of radial compressor stages with seals and technological holes

    Directory of Open Access Journals (Sweden)

    Syka Tomáš

    2014-03-01

    Full Text Available Article describes numerical simulations of an air flow in radial compressor stages in the NUMECA CFD software. Four different radial compressor stages were solved in this article. During the tasks evaluating the stepped and straight impeller seals and technological holes influence on working characteristics and the flow field was observed. Also the CFD results comparison with results from the empiric design tool is described.

  4. Prediction of Separation Length of Turbulent Multiphase Flow Using Radiotracer and Computational Fluid Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    S. Sugiharto1

    2013-04-01

    Full Text Available Multiphase flow modeling presents great challenges due to its extreme importance in various industrial and environmental applications. In the present study, prediction of separation length of multiphase flow is examined experimentally by injection of two kinds of iodine-based radiotracer solutions into a hydrocarbon transport pipeline (HCT having an inner diameter of 24 in (60,96 m. The main components of fluids in the pipeline are water 95%, crude oil 3% and gas 2%. A radiotracing experiment was carried out at the segment of pipe which is located far from branch points with assumptions that stratified flows in such segment were achieved. Two radiation detectors located at 80 and 100 m from injection point were used to generate residence time distribution (RTD curve resulting from injection of radiotracer solutions. Multiphase computational fluid dynamics (CFD simulations using Eulerian-Eulerian control volume and commercial CFD package Fluent 6.2 were employed to simulate separation length of multiphase flow. The results of study shows that the flow velocity of water is higher than the flow rate of crude oil in water-dominated system despite the higher density of water than the density of the crude oil. The separation length in multiphase flow predicted by Fluent mixture model is approximately 20 m, measured from injection point. This result confirms that the placement of the first radiation detector at the distance 80 m from the injection point was correct

  5. Prediction of Separation Length of Turbulent Multiphase Flow Using Radiotracer and Computational Fluid Dynamics Simulation

    International Nuclear Information System (INIS)

    Sugiharto, S.; Kurniadi, R.; Abidin, Z.; Stegowski, Z.; Furman, L.

    2013-01-01

    Multiphase flow modeling presents great challenges due to its extreme importance in various industrial and environmental applications. In the present study, prediction of separation length of multiphase flow is examined experimentally by injection of two kinds of iodine-based radiotracer solutions into a hydrocarbon transport pipeline (HCT) having an inner diameter of 24 in (60,96 m). The main components of fluids in the pipeline are water 95%, crude oil 3% and gas 2%. A radiotracing experiment was carried out at the segment of pipe which is located far from branch points with assumptions that stratified flows in such segment were achieved. Two radiation detectors located at 80 and 100 m from injection point were used to generate residence time distribution (RTD) curve resulting from injection of radiotracer solutions. Multiphase computational fluid dynamics (CFD) simulations using Eulerian-Eulerian control volume and commercial CFD package Fluent 6.2 were employed to simulate separation length of multiphase flow. The results of study shows that the flow velocity of water is higher than the flow rate of crude oil in water-dominated system despite the higher density of water than the density of the crude oil. The separation length in multiphase flow predicted by Fluent mixture model is approximately 20 m, measured from injection point. This result confirms that the placement of the first radiation detector at the distance 80 m from the injection point was correct. (author)

  6. Evaluation of corn/soybeans separability using Thematic Mapper and Thematic Mapper Simulator data

    Science.gov (United States)

    Pitts, D. E.; Badhwar, G. D.; Thompson, D. R.; Henderson, K. E.; Shen, S. S.; Sorensen, C. T.; Carnes, J. G.

    1984-01-01

    Multitemporal Thematic Mapper, Thematic Mapper Simulator, and detailed ground truth data were collected for a 9- by 11-km sample segment in Webster County, IA, in the summer of 1982. Three dates were acquired each with Thematic Mapper Simulator (June 7, June 23, and July 31) and Thematic Mapper (August 2, September 3, and October 21). The Thematic Mapper Simulator data were converted to equivalent TM count values using TM and TMS calibration data and model based estimates of atmospheric effects. The July 31, TMS image was compared to the August 2, TM image to verify the conversion process. A quantitative measure of proportion estimation variance (Fisher information) was used to evaluate the corn/soybeans separability for each TM band as a function of time during the growing season. The additional bands in the middle infrared allowed corn and soybeans to be separated much earlier than was possible with the visible and near-infrared bands alone. Using the TM and TMS data, temporal profiles of the TM principal components were developed. The greenness and brightness exhibited behavior similar to MSS greenness and brightness for corn and soybeans.

  7. High-Throughput Molecular Simulations of Metal Organic Frameworks for CO2 Separation: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Ilknur Erucar

    2018-02-01

    Full Text Available Metal organic frameworks (MOFs have emerged as great alternatives to traditional nanoporous materials for CO2 separation applications. MOFs are porous materials that are formed by self-assembly of transition metals and organic ligands. The most important advantage of MOFs over well-known porous materials is the possibility to generate multiple materials with varying structural properties and chemical functionalities by changing the combination of metal centers and organic linkers during the synthesis. This leads to a large diversity of materials with various pore sizes and shapes that can be efficiently used for CO2 separations. Since the number of synthesized MOFs has already reached to several thousand, experimental investigation of each MOF at the lab-scale is not practical. High-throughput computational screening of MOFs is a great opportunity to identify the best materials for CO2 separation and to gain molecular-level insights into the structure–performance relationships. This type of knowledge can be used to design new materials with the desired structural features that can lead to extraordinarily high CO2 selectivities. In this mini-review, we focused on developments in high-throughput molecular simulations of MOFs for CO2 separations. After reviewing the current studies on this topic, we discussed the opportunities and challenges in the field and addressed the potential future developments.

  8. Experimental simulation of the Paks-2 cleaning tank incident through separate effect and integral tests

    Energy Technology Data Exchange (ETDEWEB)

    Hozer, Z., E-mail: hozer@aeki.kfki.h [Hungarian Academy of Sciences KFKI Atomic Energy Research Institute, H-1525 Budapest, P.O. Box 49 (Hungary); Horvath, M.; Kunstar, M.; Matus, L.; Nagy, I.; Novotny, T.; Perez-Fero, E.; Pinter-Csordas, A.; Ver, N.; Vimi, A.; Windberg, P. [Hungarian Academy of Sciences KFKI Atomic Energy Research Institute, H-1525 Budapest, P.O. Box 49 (Hungary)

    2011-03-15

    Following the ex-core cleaning of VVER type fuel assemblies, a severe fuel damage took place at the Paks NPP. Assemblies with high decay heat remained without cooling for 7 h. As a common result of high temperature oxidation and final water quenching the assemblies were broken and the fuel rods fragmented. In order to improve the understanding of the phenomena that took place during the Paks-2 incident, several series of separate effect and integral tests have been carried out. The separate effect tests investigated the phenomena related to the upward shift of fuel assemblies, to the role of the spacer grid and the spring in the loss of cladding integrity, and to the importance of high hydrogen content in the vessel's atmosphere on the embrittlement of zirconium. Integral tests were carried out in the CODEX facility to simulate the whole scenario of the incident using electrically heated fuel rods.

  9. An Eulerian-Eulerian CFD Simulation of Air-Water Flow in a Pipe Separator

    Directory of Open Access Journals (Sweden)

    E.A. Afolabi

    2014-06-01

    Full Text Available This paper presents a three dimensional Computational Fluid Dynamics (CFD of air-water flow using Eulerian –Eulerian multiphase model and RSM mixture turbulence model to investigate its hydrodynamic flow behaviour in a 30 mm pipe separator. The simulated results are then compared with the stereoscopic PIV measurements at different axial positions. The comparison shows that the velocity distribution can be predicted with high accuracy using CFD. The numerical velocity profiles are also found to be in good qualitative agreement with the experimental measurements. However, there were some discrepancies between the CFD results and the SPIV measurements at some axial positions away from the inlet section. Therefore, the CFD model could provide good physical understanding on the hydrodynamics flow behaviour for air-water in a pipe separator.

  10. Simulation for separation of radioisotopes I-123 from tellurium target using tracer I-131

    International Nuclear Information System (INIS)

    Sarwono, Daya Agung; Amiruddin, Cahyana; Abidin; Lubis, Hotman

    2013-01-01

    Radioisotope Iodine-123 ( 123 I) can be used as material for the preparation of radiopharmaceutical imaging with SPECT tool. This is caused to 123 I emits gamma rays with energies 159 keV and a half-life 13.2 h. 123 I radioisotope was made from the target material in the form of a thin layer of solid tellurium targets with the reaction 123 Te (p, n) 123 I in energy protons 8-15 MeV or 124 Te (p, 2n) 123 I in the 20-26 MeV proton energy using the cyclotron. The use of I-131 tracer to simulate the separation of I-123 radioisotope from the tellurium target because BATAN Cyclotron CS-30 have not produce current yet so it can not generate a radioisotope I-123. Simulation of I-123 radioisotope separation from the tellurium target using tracer I-131 can be performed by irradiating solid tellurium targets in the reactor. Separation is conducted by dissolving Te targets in the target puck into the dissolution vessel with CrO 3 and H 2 SO 4 then insert to the distillation flask. Furthermore, tellurium irradiated in the reactor as a tracer was added to the distillation flask to be dissolved along with tellurium the results of electroplating. Before distilled done first iodate is reduced with oxalic acid to produce iodine. Iodine was formed, then carried distillation and distillate containing I accommodated with an alkaline solution containing sulfite Based on the results of separation experiments three times the yield were obtained with respectively 12.85%, 13.9% and 5.2% with 1-131 radio nuclide purity of 100%. (author)

  11. Glycoprotein profiles of macrophages at different stages of activation as revealed by lectin binding after electrophoretic separation.

    Science.gov (United States)

    Irimura, T; North, S M; Nicolson, G L

    1987-01-01

    Glycoprotein profiles of rat macrophages (M phi) at different stages of activation were studied by examining the reactivity of various lectins to the glycoproteins separated by polyacrylamide gel electrophoresis. Ricinus communis agglutinin 1 (RCA1) revealed several components including glycoproteins of Mr 160 kDa and 65 kDa prominent in resident M phi. A pokeweed mitogen (PWM) isolectin, Pa-4, recognizes branched poly(N-acetyllactosamine)-type carbohydrate chains, and revealed a significant increase in glycoproteins of Mr ranging from 70 kDa to 150 kDa on thioglycolate-elicited M phi. Increased reactivity of PWM to thioglycolate-elicited M phi was observed by direct binding of 125I-labeled Pa-4 to intact or glutaraldehyde-fixed M phi. Histochemical staining of formaldehyde-fixed M phi in vitro with biotinylated Pa-4 was consistent with the gel analysis, that is, resident M phi had no reactivity while thioglycolate-elicited M phi showed slight reactivity. Alveolar and intratumoral M phi bound more Pa-4 than resident or thioglycolate-elicited M phi. The PWM isolectin may therefore serve as a marker for an early stage of M phi activation.

  12. Simulation and Validation of Injection-Compression Filling Stage of Liquid Moulding with Fast Curing Resins

    Science.gov (United States)

    Martin, Ffion A.; Warrior, Nicholas A.; Simacek, Pavel; Advani, Suresh; Hughes, Adrian; Darlington, Roger; Senan, Eissa

    2018-03-01

    Very short manufacture cycle times are required if continuous carbon fibre and epoxy composite components are to be economically viable solutions for high volume composite production for the automotive industry. Here, a manufacturing process variant of resin transfer moulding (RTM), targets a reduction of in-mould manufacture time by reducing the time to inject and cure components. The process involves two stages; resin injection followed by compression. A flow simulation methodology using an RTM solver for the process has been developed. This paper compares the simulation prediction to experiments performed using industrial equipment. The issues encountered during the manufacturing are included in the simulation and their sensitivity to the process is explored.

  13. Simulation analysis of the oil/water structure in the downhole with presence of hydrocyclone separator

    Science.gov (United States)

    Jamil, I. E.; Al-Kayiem, H. H.

    2015-12-01

    The maturing oil fields with increasing water production can pose a challenge in terms of produced water handling and disposal issues. This paper presents the modelling and simulation procedure of the two-phase flow of water/oil in a downhole using ANSYS- FLUENT 14 software. The developed procedure successfully simulated the production zone and the interaction of the two fluids in a natural environment where the reservoir pressure is the sole driving force. The results show significant difference of volume distribution in the flows with different oil content. The model can become an essential tool to assist in prediction of the behavior of oil/water mixture flow in the wellbores, and to serve in designing downhole oil/water separators.

  14. Numerical Simulation of single-stage axial fan operation under dusty flow conditions

    Science.gov (United States)

    Minkov, L. L.; Pikushchak, E. V.

    2017-11-01

    Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.

  15. Method for simulating predictive control of building systems operation in the early stages of building design

    DEFF Research Database (Denmark)

    Petersen, Steffen; Svendsen, Svend

    2011-01-01

    A method for simulating predictive control of building systems operation in the early stages of building design is presented. The method uses building simulation based on weather forecasts to predict whether there is a future heating or cooling requirement. This information enables the thermal...... control systems of the building to respond proactively to keep the operational temperature within the thermal comfort range with the minimum use of energy. The method is implemented in an existing building simulation tool designed to inform decisions in the early stages of building design through...... parametric analysis. This enables building designers to predict the performance of the method and include it as a part of the solution space. The method furthermore facilitates the task of configuring appropriate building systems control schemes in the tool, and it eliminates time consuming manual...

  16. Simulated dynamic response of a multi-stage compressor with variable molecular weight flow medium

    Science.gov (United States)

    Babcock, Dale A.

    1995-01-01

    A mathematical model of a multi-stage compressor with variable molecular weight flow medium is derived. The modeled system consists of a five stage, six cylinder, double acting, piston type compressor. Each stage is followed by a water cooled heat exchanger which serves to transfer the heat of compression from the gas. A high molecular weight gas (CFC-12) mixed with air in varying proportions is introduced to the suction of the compressor. Condensation of the heavy gas may occur in the upper stage heat exchangers. The state equations for the system are integrated using the Advanced Continuous Simulation Language (ACSL) for determining the system's dynamic and steady state characteristics under varying operating conditions.

  17. Star/galaxy separation at faint magnitudes: application to a simulated Dark Energy Survey

    Energy Technology Data Exchange (ETDEWEB)

    Soumagnac, M. T.; Abdalla, F. B.; Lahav, O.; Kirk, D.; Sevilla, I.; Bertin, E.; Rowe, B. T. P.; Annis, J.; Busha, M. T.; Da Costa, L. N.; Frieman, J. A.; Gaztanaga, E.; Jarvis, M.; Lin, H.; Percival, W. J.; Santiago, B. X.; Sabiu, C. G.; Wechsler, R. H.; Wolz, L.; Yanny, B.

    2015-04-14

    We address the problem of separating stars from galaxies in future large photometric surveys. We focus our analysis on simulations of the Dark Energy Survey (DES). In the first part of the paper, we derive the science requirements on star/galaxy separation, for measurement of the cosmological parameters with the gravitational weak lensing and large-scale structure probes. These requirements are dictated by the need to control both the statistical and systematic errors on the cosmological parameters, and by point spread function calibration. We formulate the requirements in terms of the completeness and purity provided by a given star/galaxy classifier. In order to achieve these requirements at faint magnitudes, we propose a new method for star/galaxy separation in the second part of the paper. We first use principal component analysis to outline the correlations between the objects parameters and extract from it the most relevant information. We then use the reduced set of parameters as input to an Artificial Neural Network. This multiparameter approach improves upon purely morphometric classifiers (such as the classifier implemented in SExtractor), especially at faint magnitudes: it increases the purity by up to 20 per cent for stars and by up to 12 per cent for galaxies, at i-magnitude fainter than 23.

  18. Detailed high-resolution three-dimensional simulations of OMEGA separated reactants inertial confinement fusion experiments

    Energy Technology Data Exchange (ETDEWEB)

    Haines, Brian M., E-mail: bmhaines@lanl.gov; Fincke, James R.; Shah, Rahul C.; Boswell, Melissa; Fowler, Malcolm M.; Gore, Robert A.; Hayes-Sterbenz, Anna C.; Jungman, Gerard; Klein, Andreas; Rundberg, Robert S.; Steinkamp, Michael J.; Wilhelmy, Jerry B. [Los Alamos National Laboratory, MS T087, Los Alamos, New Mexico 87545 (United States); Grim, Gary P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Forrest, Chad J.; Silverstein, Kevin; Marshall, Frederic J. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2016-07-15

    We present results from the comparison of high-resolution three-dimensional (3D) simulations with data from the implosions of inertial confinement fusion capsules with separated reactants performed on the OMEGA laser facility. Each capsule, referred to as a “CD Mixcap,” is filled with tritium and has a polystyrene (CH) shell with a deuterated polystyrene (CD) layer whose burial depth is varied. In these implosions, fusion reactions between deuterium and tritium ions can occur only in the presence of atomic mix between the gas fill and shell material. The simulations feature accurate models for all known experimental asymmetries and do not employ any adjustable parameters to improve agreement with experimental data. Simulations are performed with the RAGE radiation-hydrodynamics code using an Implicit Large Eddy Simulation (ILES) strategy for the hydrodynamics. We obtain good agreement with the experimental data, including the DT/TT neutron yield ratios used to diagnose mix, for all burial depths of the deuterated shell layer. Additionally, simulations demonstrate good agreement with converged simulations employing explicit models for plasma diffusion and viscosity, suggesting that the implicit sub-grid model used in ILES is sufficient to model these processes in these experiments. In our simulations, mixing is driven by short-wavelength asymmetries and longer-wavelength features are responsible for developing flows that transport mixed material towards the center of the hot spot. Mix material transported by this process is responsible for most of the mix (DT) yield even for the capsule with a CD layer adjacent to the tritium fuel. Consistent with our previous results, mix does not play a significant role in TT neutron yield degradation; instead, this is dominated by the displacement of fuel from the center of the implosion due to the development of turbulent instabilities seeded by long-wavelength asymmetries. Through these processes, the long

  19. Effect of simulated stages of the canine oestrous cycle on Escherichia coli binding to canine endometrium.

    Science.gov (United States)

    Krekeler, N; Lodge, K M; Anderson, G A; Browning, G F; Charles, J A; Wright, P J

    2012-12-01

    Pyometra, a prevalent infectious uterine disease that affects intact middle-aged bitches, is typically associated with Escherichia coli. Our hypotheses were (i) that bacterial adhesion to canine endometrium differs between different stages of the oestrous cycle and (ii) that the adhesin FimH facilitates this adhesion. Twelve post-pubertal, ovariectomized greyhound bitches were treated with exogenous hormones to simulate different stages of the oestrous cycle. Tissue samples from each uterus were incubated with a pathogenic E. coli strain carrying the fimH gene, but no other adhesin genes (P4-wt)--or an E. coli strain in which fimH was insertionally inactivated (P4-∆fimH::kan)--or with phosphate-buffered saline as a negative control. After washing, tissue samples were homogenized for quantification of adherent bacteria. The differences in binding to canine endometrium at different stages of the oestrous cycle were not significant. However, the mean difference in binding of the P4-wt and the P4-∆fimH::kan across all stages of the simulated oestrous cycle was significant (p < 0.001 by paired t-test on geometric means). Individual differences in numbers of P4-wt bacteria bound between dogs might suggest genetic variations or epigenetic differences in FimH receptor expression by the endometrium, unrelated to the stage of the oestrous cycle. © 2012 Blackwell Verlag GmbH.

  20. Test facility simulation of WWER fuel rods behaviour under initial stage of LB LOCA

    International Nuclear Information System (INIS)

    Deniskin, V.; Konstantinov, V.; Nalivaev, V.; Parshin, N.; Fedik, I.; Semishkin, V.; Shumsky, A.

    2003-01-01

    The calculation and experimental method has been developed to calculate and to study the possibility of simulating the main parameters at the initial stage of an accident of LB LOCA-type for WWER reactor on the experimental facility. They are velocities and the way of heating of FR claddings, the levels of cladding temperatures, the rate of the external pressure drop and the creation of the natural change of pressure on the claddings at the maximum temperature. Series of experimental tests of FR simulators of WWER was carried out at the initial stage of LB LOCA. They resulted in a potential possibility of the ballooning and the depressurization of maximally heated FRs even on this stage of the accident. The results of these tests allow to study the structural changes of FR materials and to enlarge the knowledge about deformation and possible depressurization of FR claddings. To study more carefully the problems of the ballooning and a possible depressurization at the initial stage of the accident it is necessary to continue the researches and to develop scenarios of this accident for FRs with different energy release levels and to test the initial stage of LB LOCA on the experimental facility and under reactor conditions

  1. Investigation of 2-stage meta-analysis methods for joint longitudinal and time-to-event data through simulation and real data application.

    Science.gov (United States)

    Sudell, Maria; Tudur Smith, Catrin; Gueyffier, François; Kolamunnage-Dona, Ruwanthi

    2018-04-15

    Joint modelling of longitudinal and time-to-event data is often preferred over separate longitudinal or time-to-event analyses as it can account for study dropout, error in longitudinally measured covariates, and correlation between longitudinal and time-to-event outcomes. The joint modelling literature focuses mainly on the analysis of single studies with no methods currently available for the meta-analysis of joint model estimates from multiple studies. We propose a 2-stage method for meta-analysis of joint model estimates. These methods are applied to the INDANA dataset to combine joint model estimates of systolic blood pressure with time to death, time to myocardial infarction, and time to stroke. Results are compared to meta-analyses of separate longitudinal or time-to-event models. A simulation study is conducted to contrast separate versus joint analyses over a range of scenarios. Using the real dataset, similar results were obtained by using the separate and joint analyses. However, the simulation study indicated a benefit of use of joint rather than separate methods in a meta-analytic setting where association exists between the longitudinal and time-to-event outcomes. Where evidence of association between longitudinal and time-to-event outcomes exists, results from joint models over standalone analyses should be pooled in 2-stage meta-analyses. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  2. Intergranular fracture in UO2: derivation of traction-separation law from atomistic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Yongfeng Zhang; Paul C Millett; Michael R Tonks; Xian-Ming Bai; S Bulent Biner

    2013-10-01

    In this study, the intergranular fracture behavior of UO2 was studied by molecular dynamics simulations using the Basak potential. In addition, the constitutive traction-separation law was derived from atomistic data using the cohesive-zone model. In the simulations a bicrystal model with the (100) symmetric tilt E5 grain boundaries was utilized. Uniaxial tension along the grain boundary normal was applied to simulate Mode-I fracture. The fracture was observed to propagate along the grain boundary by micro-pore nucleation and coalescence, giving an overall intergranular fracture behavior. Phase transformations from the Fluorite to the Rutile and Scrutinyite phases were identified at the propagating crack tips. These new phases are metastable and they transformed back to the Fluorite phase at the wake of crack tips as the local stress concentration was relieved by complete cracking. Such transient behavior observed at atomistic scale was found to substantially increase the energy release rate for fracture. Insertion of Xe gas into the initial notch showed minor effect on the overall fracture behavior.

  3. Lattice Boltzmann simulation of phase separation under dynamic temperature and shear: Coupling effects of shear convection and thermal diffusion.

    Science.gov (United States)

    Heping, Wang; Xingguo, Geng; Xiaoguang, Li; Duyang, Zang

    2016-10-01

    This paper presents an exploration of the separation behavior and pattern formation in a shear binary fluid with dynamic temperature after slow cooling via coupled lattice Boltzmann method. The phase separation procedure can be divided into three different stages: spinodal decomposition, domain growth, and domain stretch. The effect of thermal diffusion was observed to be more significant than that of shear convection in the spinodal decomposition stage, while the opposite was observed in the domain growth stage. The slow cooling temperature field significantly prolonged the spinodal decomposition stage, and decreased the separated domain size in domain growth stage. The phase behavior and pattern formation from the disordered state into the coexistence state after slow cooling was investigated during the domain stretch stage. Two typical length scales were obtained according to the equilibrium of two phases, where the number of layers in the corresponding domains was controllable by adjusting the Prandtl number for systems of different scales. The manner in which various viscosities and thermal diffusivities influence the morphologies and kinetic characterizations of the materials was also demonstrated: numerical results indicated that decrease in viscosity can cause increase in the growth exponents of separation fronts and velocity of domain growth, as well as increase in thermal diffusion.

  4. Simulation of 3-D viscous flow within a multi-stage turbine

    Science.gov (United States)

    Adamczyk, John J.; Celestina, Mark L.; Beach, Tim A.; Barnett, Mark

    1989-01-01

    This work outlines a procedure for simulating the flow field within multistage turbomachinery which includes the effects of unsteadiness, compressibility, and viscosity. The associated modeling equations are the average passage equation system which governs the time-averaged flow field within a typical passage of a blade row embedded within a multistage configuration. The results from a simulation of a low aspect ratio stage and a one-half turbine will be presented and compared with experimental measurements. It will be shown that the secondary flow field generated by the rotor causes the aerodynamic performance of the downstream vane to be significantly different from that of an isolated blade row.

  5. Simulation and control synthesis for a pulse column separation system for plutonium--uranium recovery

    International Nuclear Information System (INIS)

    McCutcheon, E.B.

    1975-05-01

    Control of a plutonium-uranium partitioning column was studied using a mathematical model developed to simulate the dynamic response and to test postulated separation mechanisms. The column is part of a plutonium recycle flowsheet developed for the recovery of plutonium and uranium from metallurgical scrap. In the first step of the process, decontamination from impurities is achieved by coextracting plutonium and uranium in their higher oxidation states. In the second step, reduction of the plutonium to a lower oxidation state allows partitioning of the plutonium and uranium. The use of hydroxylamine for the plutonium reduction in this partitioning column is a unique feature of the process. The extraction operations are carried out in pulse columns. (U.S.)

  6. Numerical simulation and experimental visualization of the separated cavitating boundary layer over NACA2412

    Directory of Open Access Journals (Sweden)

    Kozák Jiří

    2015-01-01

    Full Text Available Cavitation is physical phenomenon of crucial impact on the operation range and service lifetime of the hydraulic machines (pumps, turbines, valves etc.. Experimental measurement of cavitation is expensive and time consuming process, while some important characteristic of the flow are difficult to measure due to the nature of the phenomenon. Current possibilities of computational fluid dynamics provide a way for deeper understanding of cavitation which is important for many applications in the hydraulic machines industry such as expanding operation range or extending lifetime of the hydraulic machines. Simplified model consists of NACA 2412 hydrofoil with 8 degrees angle of attack fixed in between the walls of cavitation tunnel. Present investigation focuses on comparison of vapor volume fractions obtained by 3D CFD simulations and high speed visualization of the real cavitation phenomena. Several operating regimes corresponding to different cavitation numbers are studied with aim to assess the dynamics of the separated cavitating sheets/clouds

  7. Deformability-based red blood cell separation in deterministic lateral displacement devices-A simulation study.

    Science.gov (United States)

    Krüger, Timm; Holmes, David; Coveney, Peter V

    2014-09-01

    We show, via three-dimensional immersed-boundary-finite-element-lattice-Boltzmann simulations, that deformability-based red blood cell (RBC) separation in deterministic lateral displacement (DLD) devices is possible. This is due to the deformability-dependent lateral extension of RBCs and enables us to predict a priori which RBCs will be displaced in a given DLD geometry. Several diseases affect the deformability of human cells. Malaria-infected RBCs, for example, tend to become stiffer than their healthy counterparts. It is therefore desirable to design microfluidic devices which can detect diseases based on the cells' deformability fingerprint, rather than preparing samples using expensive and time-consuming biochemical preparation steps. Our findings should be helpful in the development of new methods for sorting cells and particles by deformability.

  8. Deformability-based red blood cell separation in deterministic lateral displacement devices—A simulation study

    Science.gov (United States)

    Krüger, Timm

    2014-01-01

    We show, via three-dimensional immersed-boundary-finite-element-lattice-Boltzmann simulations, that deformability-based red blood cell (RBC) separation in deterministic lateral displacement (DLD) devices is possible. This is due to the deformability-dependent lateral extension of RBCs and enables us to predict a priori which RBCs will be displaced in a given DLD geometry. Several diseases affect the deformability of human cells. Malaria-infected RBCs, for example, tend to become stiffer than their healthy counterparts. It is therefore desirable to design microfluidic devices which can detect diseases based on the cells' deformability fingerprint, rather than preparing samples using expensive and time-consuming biochemical preparation steps. Our findings should be helpful in the development of new methods for sorting cells and particles by deformability. PMID:25584112

  9. The Nuclear Energy Advanced Modeling and Simulation Safeguards and Separations Reprocessing Plant Toolkit

    Energy Technology Data Exchange (ETDEWEB)

    McCaskey, Alex [ORNL; Billings, Jay Jay [ORNL; de Almeida, Valmor F [ORNL

    2011-08-01

    This report details the progress made in the development of the Reprocessing Plant Toolkit (RPTk) for the DOE Nuclear Energy Advanced Modeling and Simulation (NEAMS) program. RPTk is an ongoing development effort intended to provide users with an extensible, integrated, and scalable software framework for the modeling and simulation of spent nuclear fuel reprocessing plants by enabling the insertion and coupling of user-developed physicochemical modules of variable fidelity. The NEAMS Safeguards and Separations IPSC (SafeSeps) and the Enabling Computational Technologies (ECT) supporting program element have partnered to release an initial version of the RPTk with a focus on software usability and utility. RPTk implements a data flow architecture that is the source of the system's extensibility and scalability. Data flows through physicochemical modules sequentially, with each module importing data, evolving it, and exporting the updated data to the next downstream module. This is accomplished through various architectural abstractions designed to give RPTk true plug-and-play capabilities. A simple application of this architecture, as well as RPTk data flow and evolution, is demonstrated in Section 6 with an application consisting of two coupled physicochemical modules. The remaining sections describe this ongoing work in full, from system vision and design inception to full implementation. Section 3 describes the relevant software development processes used by the RPTk development team. These processes allow the team to manage system complexity and ensure stakeholder satisfaction. This section also details the work done on the RPTk ``black box'' and ``white box'' models, with a special focus on the separation of concerns between the RPTk user interface and application runtime. Section 4 and 5 discuss that application runtime component in more detail, and describe the dependencies, behavior, and rigorous testing of its constituent components.

  10. Transitioning Resolution Responsibility between the Controller and Automation Team in Simulated NextGen Separation Assurance

    Science.gov (United States)

    Cabrall, C.; Gomez, A.; Homola, J.; Hunt, S..; Martin, L.; Merccer, J.; Prevott, T.

    2013-01-01

    As part of an ongoing research effort on separation assurance and functional allocation in NextGen, a controller- in-the-loop study with ground-based automation was conducted at NASA Ames' Airspace Operations Laboratory in August 2012 to investigate the potential impact of introducing self-separating aircraft in progressively advanced NextGen timeframes. From this larger study, the current exploratory analysis of controller-automation interaction styles focuses on the last and most far-term time frame. Measurements were recorded that firstly verified the continued operational validity of this iteration of the ground-based functional allocation automation concept in forecast traffic densities up to 2x that of current day high altitude en-route sectors. Additionally, with greater levels of fully automated conflict detection and resolution as well as the introduction of intervention functionality, objective and subjective analyses showed a range of passive to active controller- automation interaction styles between the participants. Not only did the controllers work with the automation to meet their safety and capacity goals in the simulated future NextGen timeframe, they did so in different ways and with different attitudes of trust/use of the automation. Taken as a whole, the results showed that the prototyped controller-automation functional allocation framework was very flexible and successful overall.

  11. Optimizing the sampling and staging for simulations of rare events via forward flux sampling schemes.

    Science.gov (United States)

    Borrero, Ernesto E; Escobedo, Fernando A

    2008-07-14

    In this work, we present an adaptive algorithm to optimize the phase space sampling for simulations of rare events in complex systems via forward flux sampling (FFS) schemes. In FFS, interfaces are used to partition the phase space along an order parameter lambda connecting the initial and final regions of interest. Since the kinetic "bottleneck" regions along the order parameter are not usually known beforehand, an adaptive procedure is used that first finds these regions by estimating the rate constants associated with reaching subsequent interfaces; thereafter, the FFS simulation is reset to concentrate the sampling on those bottlenecks. The approach can optimize for either the number and position of the interfaces (i.e., optimized lambda phase staging) or the number M of fired trial runs per interface (i.e., the {M(i)} set) to minimize the statistical error in the rate constant estimation per simulation period. For example, the optimization of the lambda staging leads to a net constant flux of partial trajectories between interfaces and hence a constant flux of connected paths throughout the region between the two end states. The method is demonstrated for several test systems, including the folding of a lattice protein. It is shown that the proposed approach leads to an optimized lambda staging and {M(i)} set which increase the computational efficiency of the sampling algorithm.

  12. Photonic circuit for high order USB and LSB separation for remote heterodyning: analysis and simulation.

    Science.gov (United States)

    Hasan, Mehedi; Hall, Trevor J

    2015-09-21

    A novel photonic integrated circuit is proposed that, using an RF source, generates at its output ports the same magnitude but opposite sign high order single optical side bands of a suppressed optical carrier. A single stage parallel Mach-Zehnder Modulator (MZM) and a two-stage series parallel MZM architecture are described and their relative merits discussed. A transfer matrix method is used to describe the operation of the circuits. The theoretical analysis is validated by computer simulation. As an illustration of a prospective application, it is shown how the circuit may be used as a key element of an optical transmission system to transport radio signals over fibre for wireless access; generating remotely a mm-wave carrier modulated by digital IQ data. A detailed calculation of symbol error rate is presented to characterise the system performance. The circuit may be fabricated in any integration platform offering a suitable phase modulator circuit element such as LiNbO(3), Silicon, and III-V or hybrid technology.

  13. CO2/H2 separation using a highly permeable polyurethane membrane: Molecular dynamics simulation

    Science.gov (United States)

    Azizi, Morteza; Mousavi, Seyyed Abbas

    2015-11-01

    In this study, Molecular Dynamics (MD) and Grand Canonical Monte Carlo (GCMC) simulations were conducted to investigate the diffusivity, solubility, and permeability of CO2, CO, H2, and H2O in a polyurethane membrane at three different temperatures. The characterization of the simulated structures was carried out using XRD, FFV, Tg and density calculation, and cavity size distribution. The obtained results were within the expectations reported data in the literature based on the experimental approach, indicating the authenticity of approached in this work. The results showed that the highest diffusivity and permeability coefficients were observed for H2; while the highest values of solubility coefficient were found for H2O and CO2 gases. The increase of operating temperature from 298 K to 318 K has a positive effect on the permeation of all gases and a corresponding negative effect on the selectivity of the gas pair CO2/H2. Also, the results vividly showed that CO2 and H2O gases have a profound affinity with hard phase of polyurethane, while H2 and CO were conversely adsorbed by soft one. Moreover, the enhancement of permeability and permselectivity of CO2/H2 pair confirmed using Robeson Upper-Bond graph showed its good capacity for CO2/H2 separation application.

  14. Modelling and simulation of particle-particle interaction in a magnetophoretic bio-separation chip

    Science.gov (United States)

    Alam, Manjurul; Golozar, Matin; Darabi, Jeff

    2018-04-01

    A Lagrangian particle trajectory model is developed to predict the interaction between cell-bead particle complexes and to track their trajectories in a magnetophoretic bio-separation chip. Magnetic flux gradients are simulated in the OpenFOAM CFD software and imported into MATLAB to obtain the trapping lengths and trajectories of the particles. A connector vector is introduced to calculate the interaction force between cell-bead complexes as they flow through a microfluidic device. The interaction force calculations are performed for cases where the connector vector is parallel, perpendicular, and at an angle of 45° with the applied magnetic field. The trajectories of the particles are simulated by solving a system of eight ordinary differential equations using a fourth order Runge-Kutta method. The model is then used to study the effects of geometric positions and angles of the connector vector between the particles as well as the cell size, number of beads per cell, and flow rate on the interaction force and trajectories of the particles. The results show that the interaction forces may be attractive or repulsive, depending on the orientation of the connector vector distance between the particle complexes and the applied magnetic field. When the interaction force is attractive, the particles are observed to merge and trap sooner than a single particle, whereas a repulsive interaction force has little or no effect on the trapping length.

  15. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad/Separation Bolt Wedge Tests

    Science.gov (United States)

    Goekcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Each panel test article included a metallic separation bolt imbedded in Orion compression-pad and heatshield materials, resulting in a circular protuberance over a flat plate. The protuberances produce complex model flowfields, containing shock-shock and shock-boundary layer interactions, and multiple augmented heating regions on the test plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the nonequilibrium flowfield in the facility nozzle, test box, and flowfield over test articles, and comparisons with the measured calibration data.

  16. CFD Simulations of the IHF Arc-Jet Flow: Compression-Pad Separation Bolt Wedge Tests

    Science.gov (United States)

    Gokcen, Tahir; Skokova, Kristina A.

    2017-01-01

    This paper reports computational analyses in support of two wedge tests in a high enthalpy arc-jet facility at NASA Ames Research Center. These tests were conducted using two different wedge models, each placed in a free jet downstream of a corresponding different conical nozzle in the Ames 60-MW Interaction Heating Facility. Each panel test article included a metallic separation bolt imbedded in Orion compression-pad and heatshield materials, resulting in a circular protuberance over a flat plate. The protuberances produce complex model flowfields, containing shock-shock and shock-boundary layer interactions, and multiple augmented heating regions on the test plate. As part of the test calibration runs, surface pressure and heat flux measurements on water-cooled calibration plates integrated with the wedge models were also obtained. Surface heating distributions on the test articles as well as arc-jet test environment parameters for each test configuration are obtained through computational fluid dynamics simulations, consistent with the facility and calibration measurements. The present analysis comprises simulations of the non-equilibrium flow field in the facility nozzle, test box, and flow field over test articles, and comparisons with the measured calibration data.

  17. Vortex Lattice Simulations of Attached and Separated Flows around Flapping Wings

    Directory of Open Access Journals (Sweden)

    Thomas Lambert

    2017-04-01

    Full Text Available Flapping flight is an increasingly popular area of research, with applications to micro-unmanned air vehicles and animal flight biomechanics. Fast, but accurate methods for predicting the aerodynamic loads acting on flapping wings are of interest for designing such aircraft and optimizing thrust production. In this work, the unsteady vortex lattice method is used in conjunction with three load estimation techniques in order to predict the aerodynamic lift and drag time histories produced by flapping rectangular wings. The load estimation approaches are the Katz, Joukowski and simplified Leishman–Beddoes techniques. The simulations’ predictions are compared to experimental measurements from wind tunnel tests of a flapping and pitching wing. Three types of kinematics are investigated, pitch-leading, pure flapping and pitch lagging. It is found that pitch-leading tests can be simulated quite accurately using either the Katz or Joukowski approaches as no measurable flow separation occurs. For the pure flapping tests, the Katz and Joukowski techniques are accurate as long as the static pitch angle is greater than zero. For zero or negative static pitch angles, these methods underestimate the amplitude of the drag. The Leishman–Beddoes approach yields better drag amplitudes, but can introduce a constant negative drag offset. Finally, for the pitch-lagging tests the Leishman–Beddoes technique is again more representative of the experimental results, as long as flow separation is not too extensive. Considering the complexity of the phenomena involved, in the vast majority of cases, the lift time history is predicted with reasonable accuracy. The drag (or thrust time history is more challenging.

  18. Continuous separation of protein loaded nanoparticles by simulated moving bed chromatography.

    Science.gov (United States)

    Satzer, Peter; Wellhoefer, Martin; Jungbauer, Alois

    2014-07-04

    For scale up and efficient production of protein loaded nanoparticles continuous separation by size exclusion chromatography in simulated moving bed (SMB) mode helps do reduce unbound protein concentration and increase yields for perfectly covered particles. Silica nanoparticles were loaded with an excess of beta casein or bovine serum albumin (BSA) and the loaded particles purified by size exclusion chromatography using Sephacryl300 as stationary phase in a four zone SMB. We determined our working points for the SMB from batch separations and the triangle theory described by Mazzotti et al. with an SMB setup of one Sephacryl300 26/70mm column per zone with switch times of 5min for BSA and 7min for beta casein. In the case of BSA the Raffinate contained loaded nanoparticles of 63% purity with 98% recovery and the extract was essentially particle free (95% purity). We showed that the low purity of the Raffinate was only due to BSA multimers present in the used protein solution. In the case of beta casein where no multimers are present we achieved 89% purity and 90% recovery of loaded nanoparticles in the Raffinate and an extract free of particles (92% purity). Using a tangential flow filtration unit with 5kDa cutoff membrane we proved that the extract can be concentrated for recycling of protein and buffer. The calculated space-time-yield for loaded nanoparticles was 0.25g of loaded nanoparticles per hour and liter of used resin. This proves that the presented process is suitable for large scale production for industrial purposes. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Optimal topotactic conversion of layered octosilicate to RWR-type zeolite by separating the formation stages of interlayer condensation and elimination of organic guest molecules.

    Science.gov (United States)

    Asakura, Yusuke; Osada, Shimon; Hosaka, Nami; Terasawa, Taichi; Kuroda, Kazuyuki

    2014-07-21

    We demonstrate that the separation of two stages of interlayer condensation under refluxing and elimination of organic guests provides the optimal conditions for the formation of RWR-type zeolite from layered octosilicate. The obtained RWR-type zeolite has higher quality than any other RWR-type zeolite reported previously.

  20. Dynamic modeling and simulation of a two-stage series-parallel vibration isolation system

    Directory of Open Access Journals (Sweden)

    Rong Guo

    2016-07-01

    Full Text Available A two-stage series-parallel vibration isolation system is already widely used in various industrial fields. However, when the researchers analyze the vibration characteristics of a mechanical system, the system is usually regarded as a single-stage one composed of two substructures. The dynamic modeling of a two-stage series-parallel vibration isolation system using frequency response function–based substructuring method has not been studied. Therefore, this article presents the source-path-receiver model and the substructure property identification model of such a system. These two models make up the transfer path model of the system. And the model is programmed by MATLAB. To verify the proposed transfer path model, a finite element model simulating a vehicle system, which is a typical two-stage series-parallel vibration isolation system, is developed. The substructure frequency response functions and system level frequency response functions can be obtained by MSC Patran/Nastran and LMS Virtual.lab based on the finite element model. Next, the system level frequency response functions are substituted into the transfer path model to predict the substructural frequency response functions and the system response of the coupled structure can then be further calculated. By comparing the predicted results and exact value, the model proves to be correct. Finally, the random noise is introduced into several relevant system level frequency response functions for error sensitivity analysis. The system level frequency response functions that are most sensitive to the random error are found. Since a two-stage series-parallel system has not been well studied, the proposed transfer path model improves the dynamic theory of the multi-stage vibration isolation system. Moreover, the validation process of the model here actually provides an example for acoustic and vibration transfer path analysis based on the proposed model. And it is worth noting that the

  1. Dislocation based controlling of kinematic hardening contribution to simulate primary and secondary stages of uniaxial ratcheting

    Science.gov (United States)

    Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.

    2017-07-01

    The primary and secondary stages of the uniaxial ratcheting curve for the C-Mn steel SA333 have been investigated. Stress controlled uniaxial ratcheting experiments were conducted with different mean stresses and stress amplitudes to obtain curves showing the evolution of ratcheting strain with number of cycles. In stage-I of the ratcheting curve, a large accumulation of ratcheting strain occurs, but at a decreasing rate. In contrast, in stage-II a smaller accumulation of ratcheting strain is found and the ratcheting rate becomes almost constant. Transmission electron microscope observations reveal that no specific dislocation structures are developed during the early stages of ratcheting. Rather, compared with the case of low cycle fatigue, it is observed that sub-cell formation is delayed in the case of ratcheting. The increase in dislocation density as a result of the ratcheting strain is obtained using the Orowan equation. The ratcheting strain is obtained from the shift of the plastic strain memory surface. The dislocation rearrangement is incorporated in a functional form of dislocation density, which is used to calibrate the parameters of a kinematic hardening law. The observations are formulated in a material model, plugged into the ABAQUS finite element (FE) platform as a user material subroutine. Finally the FE-simulated ratcheting curves are compared with the experimental curves.

  2. Computer simulation of the pneumatic separator in the pneumatic-electrostatic separation system for recycling waste printed circuit boards with electronic components.

    Science.gov (United States)

    Xue, Mianqiang; Xu, Zhenming

    2013-05-07

    Technologies could be integrated in different ways into automatic recycling lines for a certain kind of electronic waste according to practical requirements. In this study, a new kind of pneumatic separator with openings at the dust hooper was applied combing with electrostatic separation for recycling waste printed circuit boards. However, the flow pattern and the particles' movement behavior could not be obtained by experimental methods. To better control the separation quantity and the material size distribution, computational fluid dynamics was used to model the new pneumatic separator giving a detailed understanding of the mechanisms. Simulated results showed that the tangential velocity direction reversed with a relatively small value. Axial velocity exhibited two sharp decreases at the x axis. It is indicated that the bottom openings at the dust hopper resulted in an enormous change in the velocity profile. A new phenomenon that was named dusting was observed, which would mitigate the effect of particles with small diameter on the following electrostatic separation and avoid materials plugging caused by the waste printed circuit boards special properties effectively. The trapped materials were divided into seven grades. Experimental results showed that the mass fraction of grade 5, grade 6, and grade 7 materials were 27.54%, 15.23%, and 17.38%, respectively. Grade 1 particles' mass fraction was reduced by 80.30% compared with a traditional separator. Furthermore, the monocrystalline silicon content in silicon element in particles with a diameter of -0.091 mm was 18.9%, higher than that in the mixed materials. This study could serve as guidance for the future material flow control, automation control, waste recycling, and semiconductor storage medium destruction.

  3. Research on the separation properties of empty-column gas chromatography (EC-GC) and conditions for simulated distillation (SIMDIS).

    Science.gov (United States)

    Boczkaj, Grzegorz; Kamiński, Marian

    2013-10-01

    Previous studies have revealed it is possible to separate a high-boiling mixture by gas chromatography in empty fused-silica capillary tubing rather than in columns coated with stationary phase. Chromatographic separation occurs solely on the basis of the different boiling points of the substances separated. The high similarity of such separations to those in classic distillation seems advantageous when gas chromatography is used for simulated distillation. This paper presents results from further research on the separation properties of empty fused silica tubing. The efficiency of this chromatographic system has been examined. The usefulness of such conditions has been studied for simulated distillation, i.e. to determine the boiling-point distribution of complex mixtures, mainly petroleum fractions and products, on the basis of their retention relative to reference substances. The results obtained by use of empty-column gas chromatography (EC-GC) and by use of classical simulated distillation columns have been compared for solutes of different polarity. Studies revealed boiling points determined by EC-GC were more accurate than those obtained by the standard method of simulated distillation.

  4. Swirling Combustor Energy Converter: H2/Air Simulations of Separated Chambers

    Directory of Open Access Journals (Sweden)

    Angelo Minotti

    2015-09-01

    Full Text Available This work reports results related to the “EU-FP7-HRC-Power” project aiming at developing micro-meso hybrid sources of power. One of the goals of the project is to achieve surface temperatures up to more than 1000 K, with a ∆T ≤ 100 K, in order to be compatible with a thermal/electrical conversion by thermo-photovoltaic cells. The authors investigate how to reach that goal adopting swirling chambers integrated in a thermally-conductive and emitting element. The converter consists of a small parallelepiped brick inside two separated swirling meso-combustion chambers, which heat up the parallelepiped, emitting material by the combustion of H2 and air at ambient pressure. The overall dimension is of the order of cm. Nine combustion simulations have been carried out assuming detailed chemistry, several length/diameter ratios (Z/D = 3, 5 and 11 and equivalence ratios (0.4, 0.7 and 1; all are at 400 W of injected chemical power. Among the most important results are the converter surfaces temperatures, the heat loads, provided to the environment, and the chemical efficiency. The high chemical efficiency, h > 99.9%, is due to the relatively long average gas residence time coupled with the fairly good mixing due to the swirl motion and the impinging air/fuel jets that provide heat and radicals to the flame.

  5. Simulation model of a single-stage lithium bromide-water absorption cooling unit

    Science.gov (United States)

    Miao, D.

    1978-01-01

    A computer model of a LiBr-H2O single-stage absorption machine was developed. The model, utilizing a given set of design data such as water-flow rates and inlet or outlet temperatures of these flow rates but without knowing the interior characteristics of the machine (heat transfer rates and surface areas), can be used to predict or simulate off-design performance. Results from 130 off-design cases for a given commercial machine agree with the published data within 2 percent.

  6. Phase-field simulations of nuclei and early stage solidification microstructures.

    Science.gov (United States)

    Nestler, B; Selzer, M; Danilov, D

    2009-11-18

    To investigate the local properties of heterogeneous nuclei on substrates, a phase-field model is extended to incorporate volume constraints and a third order line tension in the gradient free energy density formulation. The new model is applied to sessile drop simulations of Cu nuclei on Ni substrates to precisely analyse 3D equilibrium shapes and diffusion processes across the phase boundaries. In particular, the formalism with higher order potentials is used to investigate the length-scale dependent effect of the line tension on Young's force balance at triple lines in 3D. The employment of parallel and adaptive simulation techniques is essential for three-dimensional numerical computations. Early stage solidification microstructures of cubic Ni crystals are simulated by scale-bridging molecular dynamics (MD) and phase-field (PF) simulations. The domain of the PF computations is initialized by transferring MD data of the atomic positions and of the shape of the nuclei. The combined approach can be used to study the responses of microstructures upon nucleation.

  7. Direct Numerical Simulation of Turbulent Multi-Stage Autoignition Relevant to Engine Conditions

    Science.gov (United States)

    Chen, Jacqueline

    2017-11-01

    Due to the unrivaled energy density of liquid hydrocarbon fuels combustion will continue to provide over 80% of the world's energy for at least the next fifty years. Hence, combustion needs to be understood and controlled to optimize combustion systems for efficiency to prevent further climate change, to reduce emissions and to ensure U.S. energy security. In this talk I will discuss recent progress in direct numerical simulations of turbulent combustion focused on providing fundamental insights into key `turbulence-chemistry' interactions that underpin the development of next generation fuel efficient, fuel flexible engines for transportation and power generation. Petascale direct numerical simulation (DNS) of multi-stage mixed-mode turbulent combustion in canonical configurations have elucidated key physics that govern autoignition and flame stabilization in engines and provide benchmark data for combustion model development under the conditions of advanced engines which operate near combustion limits to maximize efficiency and minimize emissions. Mixed-mode combustion refers to premixed or partially-premixed flames propagating into stratified autoignitive mixtures. Multi-stage ignition refers to hydrocarbon fuels with negative temperature coefficient behavior that undergo sequential low- and high-temperature autoignition. Key issues that will be discussed include: 1) the role of mixing in shear driven turbulence on the dynamics of multi-stage autoignition and cool flame propagation in diesel environments, 2) the role of thermal and composition stratification on the evolution of the balance of mixed combustion modes - flame propagation versus spontaneous ignition - which determines the overall combustion rate in autoignition processes, and 3) the role of cool flames on lifted flame stabilization. Finally prospects for DNS of turbulent combustion at the exascale will be discussed in the context of anticipated heterogeneous machine architectures. sponsored by DOE

  8. The Importance of Positive Immunomagnetic Cell Separation Prior to Autologous Hematopoetic Stem Cell Transplantation for Advanced Stage Lymphomas

    Directory of Open Access Journals (Sweden)

    Benedek István

    2016-12-01

    Full Text Available We present the method of immunomagnetic stem cell separation with the ISOLEX 300i device (Isolex® 300i Magnetic Cell Selection System, Nextell Therapeutics Inc. Irvine California 21618 USA and the results obtained using this method in patients admitted to the Hematology and Bone Marrow Transplantation Clinic of Tîrgu Mureş, Romania. Cell selection has a great importance in separating stem cells from tumor cells, therefore contributing to the success of autologous stem cell transplantation.

  9. Teaching Simulation and Computer-Aided Separation Optimization in Liquid Chromatography by Means of Illustrative Microsoft Excel Spreadsheets

    Science.gov (United States)

    Fasoula, S.; Nikitas, P.; Pappa-Louisi, A.

    2017-01-01

    A series of Microsoft Excel spreadsheets were developed to simulate the process of separation optimization under isocratic and simple gradient conditions. The optimization procedure is performed in a stepwise fashion using simple macros for an automatic application of this approach. The proposed optimization approach involves modeling of the peak…

  10. Fruit and vegetables should be targeted separately in health promotion programmes: differences in consumption levels, barriers, knowledge and stages of readiness for change.

    Science.gov (United States)

    Glasson, Colleen; Chapman, Kathy; James, Erica

    2011-04-01

    The aim of the present study was to investigate whether fruit and vegetables should be treated as separate groups in health promotion programmes by examining consumption levels, barriers, knowledge and the association between stage of change and potential predictors of fruit and vegetable intake. Computer-assisted telephone interview survey of the target population. Hunter and New England regions of New South Wales, Australia. A total of 1403 parents and carers of primary-school-aged children. Consumption levels and knowledge of recommended intakes and serving size were greater for fruit than for vegetables. There were some differences in the main barriers to the consumption of fruit compared with those cited for vegetables. There was little congruence between the stages of change for fruit consumption and those for vegetable consumption. For fruit, knowledge of serving size and recommended intake, perceptions of adequate consumption, changes made to family intake and educational attainment were all correlated with stage of change categorisation. For vegetables, knowledge of recommended intake, perceptions of adequate consumption and changes made to family intake were correlated with stage of change categorisation. Significant differences in consumption levels, barriers, knowledge and stages of readiness for change can be shown when fruit and vegetables are treated as separate groups. Health promotion planners may need to consider interventions that focus on improving vegetable consumption in preference to fruit consumption. Messages about the recommended number of servings and serving size must be simplified and this may be achieved by targeting messages towards vegetable consumption.

  11. Thermodynamic simulation of condensation heat recovery characteristics of a single stage centrifugal chiller in a hotel

    International Nuclear Information System (INIS)

    Gong, Guangcai; Chen, Feihu; Su, Huan; Zhou, Jianyong

    2012-01-01

    Highlights: ► Thermodynamic model of a two-condenser condensation system has been carried out. ► Dynamic simulation method has been presented. ► COP and g of the refrigerating system is better than the single condensation system. ► The optimal parameters for the two-condenser condensation system have been studied. -- Abstract: A thermodynamic simulation study has been carried out for a single stage centrifugal chiller in this paper. The cooling capacity of the chiller unit is about 1750 kW. The chiller unit has been set and tested, and the work refrigerant is R22. A heat exchanger has been set between outlet of the compressor and the condenser for sanitary hot water supplying. Then the chiller unit is a kind of combined system that can provide sanitary hot water supplying and air conditioning simultaneously. A thermodynamic simulation model of the combined system has been established with the system simulation toolbox Simulink. Performance of the components and the combined system of the chiller unit has been studied over a wide range of operating conditions. The potential energy and fuel cost saving associated with the use of the proposed combined system for a typical hotel in south China has been estimated. It is showed that the combined system of the chiller unit is very useful in hotel buildings. And the thermodynamic simulation model of the combined system is significance for the optimization of parameters of the chiller unit such as condensation and evaporation temperature, mass flow of the sanitary hot water and size of hot water storage tank.

  12. Comparing stochastic differential equations and agent-based modelling and simulation for early-stage cancer.

    Science.gov (United States)

    Figueredo, Grazziela P; Siebers, Peer-Olaf; Owen, Markus R; Reps, Jenna; Aickelin, Uwe

    2014-01-01

    There is great potential to be explored regarding the use of agent-based modelling and simulation as an alternative paradigm to investigate early-stage cancer interactions with the immune system. It does not suffer from some limitations of ordinary differential equation models, such as the lack of stochasticity, representation of individual behaviours rather than aggregates and individual memory. In this paper we investigate the potential contribution of agent-based modelling and simulation when contrasted with stochastic versions of ODE models using early-stage cancer examples. We seek answers to the following questions: (1) Does this new stochastic formulation produce similar results to the agent-based version? (2) Can these methods be used interchangeably? (3) Do agent-based models outcomes reveal any benefit when compared to the Gillespie results? To answer these research questions we investigate three well-established mathematical models describing interactions between tumour cells and immune elements. These case studies were re-conceptualised under an agent-based perspective and also converted to the Gillespie algorithm formulation. Our interest in this work, therefore, is to establish a methodological discussion regarding the usability of different simulation approaches, rather than provide further biological insights into the investigated case studies. Our results show that it is possible to obtain equivalent models that implement the same mechanisms; however, the incapacity of the Gillespie algorithm to retain individual memory of past events affects the similarity of some results. Furthermore, the emergent behaviour of ABMS produces extra patters of behaviour in the system, which was not obtained by the Gillespie algorithm.

  13. Mortality sensitivity in life-stage simulation analysis: A case study of southern sea otters

    Science.gov (United States)

    Gerber, L.R.; Tinker, M.T.; Doak, D.F.; Estes, J.A.; Jessup, David A.

    2004-01-01

    Currently, there are no generally recognized approaches for linking detailed mortality and pathology data to population-level analyses of extinction risk. We used a combination of analytical and simulation-based analyses to examine 20 years of age- and sex-specific mortality data for southern sea otters (Enhydra lutris), and we applied results to project the efficacy of alternative conservation strategies. Population recovery of the southern sea otter has been slow (rate of population increase ?? = 1.05) compared to other recovering populations (?? = 1.17-1.20), and the population declined (?? = 0.975) between 1995 and 1999. Age-based Leslie matrices were developed to explore explanations for the slow recovery and recent decline in the southern sea other population. An elasticity analysis was performed to predict effects of proportional changes in stage-specific reproductive or survival rates on the rate of population increase. A life-stage simulation analysis (LSA) was developed to evaluate the impact of changing age- and cause-specific mortality rates on ??. The information used to develop these models was derived from death assemblage, pathology, and live population census data to examine the sensitivity of sea otter population growth to different sources of mortality (e.g., disease and starvation, direct human take [fisheries, gun shot, boat strike, oil pollution], mating trauma and intraspecific aggression, shark bites, and unknown). We used resampling simulations to generate random combinations of vital rates for a large number of matrix replicates and drew on these to estimate potential effects of mortality sources on population growth (??). Our analyses suggest management actions that are likely and unlikely to promote recovery of the southern sea otter and more broadly indicate a methodology to better utilize cause-of-death data in conservation decision-making.

  14. Numerical Simulation of Fragment Separation during Rock Cutting Using a 3D Dynamic Finite Element Analysis Code

    Directory of Open Access Journals (Sweden)

    Zhenguo Lu

    2017-01-01

    Full Text Available To predict fragment separation during rock cutting, previous studies on rock cutting interactions using simulation approaches, experimental tests, and theoretical methods were considered in detail. This study used the numerical code LS-DYNA (3D to numerically simulate fragment separation. In the simulations, a damage material model and erosion criteria were used for the base rock, and the conical pick was designated a rigid material. The conical pick moved at varying linear speeds to cut the fixed base rock. For a given linear speed of the conical pick, numerical studies were performed for various cutting depths and mechanical properties of rock. The numerical simulation results demonstrated that the cutting forces and sizes of the separated fragments increased significantly with increasing cutting depth, compressive strength, and elastic modulus of the base rock. A strong linear relationship was observed between the mean peak cutting forces obtained from the numerical, theoretical, and experimental studies with correlation coefficients of 0.698, 0.8111, 0.868, and 0.768. The simulation results also showed an exponential relationship between the specific energy and cutting depth and a linear relationship between the specific energy and compressive strength. Overall, LS-DYNA (3D is effective and reliable for predicting the cutting performance of a conical pick.

  15. NDDP multi-stage flash desalination process simulator design process optimization

    International Nuclear Information System (INIS)

    Sashi Kumar, G.N.; Mahendra, A.K.; Sanyal, A.; Gouthaman, G.

    2009-03-01

    The improvement of NDDP-MSF plant's performance ratio (PR) from design value of 9.0 to 13.1 was achieved by optimizing the plant's operating parameters within the feasible zone of operation. This plant has 20% excess heat transfer area over the design condition which helped us to get a PR of 15.1 after optimization. Thus we have obtained, (1) A 45% increase in the output over design value by the optimization carried out with design heat transfer area. (2) A 68% increase in the output over design value by the optimization carried out with increased heat transfer area. This report discusses the approach, methodology and results of the optimization study carried out. A simulator, MSFSIM which predicts the performance of a multi-stage flash (MSF) desalination plant has been coupled with Genetic Algorithm (GA) optimizer. Exhaustive optimization case studies have been conducted on this plant with an objective to increase the performance ratio (PR). The steady state optimization performed was based on obtaining the best stage wise pressure profile to enhance thermal efficiency which in-turn improves the performance ratio. Apart from this, the recirculating brine flow rate was also optimized. This optimization study enabled us to increase the PR of NDDP-MSF plant from design value of 9.0 to an optimized value 13.1. The actual plant is provided with 20% additional heat transfer area over and above the design heat transfer area. Optimization with this additional heat transfer area has taken the PR to 15.1. A desire to maintain equal flashing rates in all of the stages (a feature required for long life of the plant and to avoid cascading effect of non-flashing triggered by any stage) of the MSF plant has also been achieved. The deviation in the flashing rates within stages has been reduced. The startup characteristic of the plant (i.e the variation of stage pressure and the variation of recirculation flow rate with time), have been optimized with a target to minimize the

  16. Isolation of intracellular parasites (Plasmodium falciparum) from culture using free-flow electrophoresis: separation of the free parasites according to stages.

    Science.gov (United States)

    Heidrich, H G; Mrema, J E; Vander Jagt, D L; Reyes, P; Rieckmann, K H

    1982-06-01

    Parasitized human erythrocytes were concentrated from continuous cultures of Plasmodium falciparum from 5-7% up to 80-95% using Plasmagel. After aggregation of the cells with phythemagglutinin, the aggregated erythrocytes were fragmented by passing them, with minimal force, through successive nylon filters of decreasing pore size (100 microns-3 microns). The mixture of liberated, free parasites, intact erythrocytes and erythrocyte membrane vesicles was separated using free-flow electrophoresis. Most of the fractions containing free parasites did not show contamination with erythrocyte constituents as determined by light and electron microscopy, polyacrylamide gel electrophoresis, and enzymatic analysis. In addition, the various stages of free parasites of Plasmodium falciparum exhibited different electrical surface charges. Rings and trophozoites were highly negatively charged whereas schizonts and, in particular, merozoites showed low negative charges. Thus, the various stages could be isolated separate from each other.

  17. Volatiles identified from five stages of embryo development separated from a heterogeneous suspension culture of Daucus carota.

    Science.gov (United States)

    Kennedy, A H; Chamberlain, D; Wilson, G; Ryan, M F

    1991-11-01

    Five stages of embryo development were fractionated from a mature culture of Daucus carota (Gelbe Rheinsche), using a series of metal sieves. The composition of the population of embryos in each fraction was determined quantitatively from microscopic investigations. Volatiles from samples of tissue from six stages of development were trapped on activated charcoal cartridges. These volatiles, some of which may play a significant role in the interaction of the plant with the carrot root fly (Psila rosae), were analysed using gas chromatography/mass spectroscopy. The resulting chromatograms are arranged in order of embryo development. The progressive elaboration of the volatile profile reflects the increased biosynthetic capacity of the developing embryo.

  18. An Advanced TALSPEAK Concept for Separating Minor Actinides. Part 2. Flowsheet Test with Actinide-spiked Simulant

    Energy Technology Data Exchange (ETDEWEB)

    Wilden, Andreas [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Lumetta, Gregg J. [Nuclear Science and Engineering Group, Pacific Northwest National Laboratory, Richland, DC, USA; Sadowski, Fabian [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Schmidt, Holger [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Schneider, Dimitri [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Gerdes, Markus [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Law, Jack D. [Aqueous Separations and Radiochemistry Department, Idaho National Laboratory, Idaho Falls, ID, USA; Geist, Andreas [Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal (INE), Karlsruhe, Germany; Bosbach, Dirk [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany; Modolo, Giuseppe [Forschungszentrum Jülich GmbH, Institut für Energie – und Klimaforschung – Nukleare Entsorgung und Reaktorsicherheit (IEK-6), Jülich, Germany

    2017-08-17

    A solvent extraction system has been developed for separating trivalent actinides from lanthanides. This “Advanced TALSPEAK” system uses 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester to extract the lanthanides into a n-dodecane-based solvent phase, while the actinides are retained in a citrate-buffered aqueous phase by complexation to N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid. Batch distribution measurements indicate that the separation of americium from the light lanthanides decreases as the pH decreases. For example, the separation factor between La and Am increases from 2.5 at pH 2.0 to 19.3 at pH 3.0. However, previous investigations indicated that the extraction rates for the heavier lanthanides decrease with increasing pH. So, a balance between these two competing effects is required. An aqueous phase in which the pH was set at 2.6 was chosen for further process development because this offered optimal separation, with a minimum separation factor of ~8.4, based on the separation between La and Am. Centrifugal contactor single-stage efficiencies were measured to characterize the performance of the system under flow conditions.

  19. Simulation studies of a possible multi-stage XFEL at ELETTRA

    International Nuclear Information System (INIS)

    Fawley, William M.; Barletta, William A.; Bocchetta, Carlo J.; Bonifacio, Rodolfo

    2002-01-01

    Presently there is strong interest in developing a 4th generation light source at VUV and soft x-ray wavelengths at the ELETTRA facility at Trieste. One proposal centers around using the existing linac at 1.0 GeV energy with a new photocathode and bunch compression to achieve an output beam at 600 Amp current, 2-4 mm-mrad normalized emittance, and 0.05 percent instantaneous energy spread. To achieve output radiation in the 10- to 40-nm wavelength region, we consider a multi-stage device which is initiated by a coherent seed laser operating at 200 nm. We present numerical simulations of various undulator/optical-klystron configurations, seeking to optimize the overall output power level while minimizing the total length of undulator sections needed. Our results suggest multi-MW instantaneous powers are possible at 10-nm wavelengths

  20. Molecular dynamics simulations on gate opening in ZIF-8: Identification of factors for ethane and propane separation

    KAUST Repository

    Zheng, Bin

    2013-07-16

    Gate opening of zeolitic imidazolate frameworks (ZIFs) is an important microscopic phenomenon in explaining the adsorption, diffusion, and separation processes for large guest molecules. We present a force field, with input from density functional theory (DFT) calculations, for the molecular dynamics simulation on the gate opening in ZIF-8. The computed self-diffusivities for sorbed C1 to C3 hydrocarbons were in good agreement with the experimental values. The observed sharp diffusion separation from C2H6 to C3H8 was elucidated by investigating the conformations of the guest molecules integrated with the flexibility of the host framework. © 2013 American Chemical Society.

  1. Simulation of an electrostatic soot-filter with continuous electrochemical conversion during the stages of development

    International Nuclear Information System (INIS)

    Muri, M.

    1996-04-01

    The dissertation describes the simulation of an electrostatic Diesel-Soot-Converter during its stages of development. This simulation is not only necessary for the interpretation of the experimental results, it also shows results for assumptions that cannot be received experimentally. The Diesel-Soot-Converter consists of a charging electrode, which charges the particles by a high-voltage and a ceramic monolith, where the particles are precipitated in the open channels because of an electric field created also by a high-voltage. Afterwards the particles are burned by a plasma. The filter-function of the Diesel-Soot-Converter was formulated and the efficiency for a vehicle was calculated. In the first part of the calculation the mass flow of a BMW 318tds and a BMW 325tds was determined for an US-FTP75-testcycle and for fuel load. In the second part the efficiency of different Diesel-Soot-Converter-types was calculated for the US-FTP75-testcycle and for full load. The use of the program with other testcycles is possible. The results of the calculations show the best configuration of the Diesel-Soot-Converter for the corresponding vehicle. Therefore with the help of this program time and money for the production of the ceramic can be saved. (author)

  2. Simulation of the Two Stages Stretch-Blow Molding Process: Infrared Heating and Blowing Modeling

    International Nuclear Information System (INIS)

    Bordival, M.; Schmidt, F. M.; Le Maoult, Y.; Velay, V.

    2007-01-01

    In the Stretch-Blow Molding (SBM) process, the temperature distribution of the reheated perform affects drastically the blowing kinematic, the bottle thickness distribution, as well as the orientation induced by stretching. Consequently, mechanical and optical properties of the final bottle are closely related to heating conditions. In order to predict the 3D temperature distribution of a rotating preform, numerical software using control-volume method has been developed. Since PET behaves like a semi-transparent medium, the radiative flux absorption was computed using Beer Lambert law. In a second step, 2D axi-symmetric simulations of the SBM have been developed using the finite element package ABAQUS registered . Temperature profiles through the preform wall thickness and along its length were computed and applied as initial condition. Air pressure inside the preform was not considered as an input variable, but was automatically computed using a thermodynamic model. The heat transfer coefficient applied between the mold and the polymer was also measured. Finally, the G'sell law was used for modeling PET behavior. For both heating and blowing stage simulations, a good agreement has been observed with experimental measurements. This work is part of the European project ''APT P ACK'' (Advanced knowledge of Polymer deformation for Tomorrow's PACKaging)

  3. Dry Separation of Palm Kernel and Palm Shell Using a Novel Five-Stage Winnowing Column System

    Directory of Open Access Journals (Sweden)

    Rohaya Mohamed Halim

    2016-04-01

    Full Text Available The conventional separation system for the recovery of palm kernel from its palm shell–kernel mixture using water as process media generates a considerable amount of waste effluent that harms the environment. The aim of this study is to develop a dry separation process for the recovery of palm kernel by using winnowing columns. A commercial system consisting of a series of five winnowing columns was developed and installed at a local palm oil mill. The system parameters, including column height, blower capacity, airflow rate and mesh screen size for shell removal, were studied and optimized to ensure good separation of kernel and shell in the column to enable collection of different sizes of kernel and shell at each column outlet. The performance of the separation process was evaluated in terms of its kernel losses, dirt content and kernel recovery rate. The average kernel losses based on oil palm fresh fruit bunches processed were found to vary from 0.11 to 0.30 wt %, with most of the values obtained being below the targeted limit of 0.30 wt %. The dirt content was in the range 4.56–6.03 wt %, which was mostly below the targeted limit of 5.5 wt %. The kernel recovery rate was in the range 5.69–6.89 wt %, with most of the values achieving the minimum targeted limit of 6.00 wt %. The system operates under completely dry conditions and, therefore, produces zero waste effluent.

  4. A review of recent advances in molecular simulation of graphene-derived membranes for gas separation

    Science.gov (United States)

    Fatemi, Seyyed Mahmood; Abbasi, Zeynab; Rajabzadeh, Halimeh; Hashemizadeh, Seyyed Ali; Deldar, Amir Noori

    2017-07-01

    To obtain an ideal membrane for gas separation the following three characteristics should be considered: the membrane should be as thin as possible, be mechanically robust, and have well-defined pore sizes. These features will maximize its solvent flux, preserve it from fracture, and guarantee its selectivity. These attractive properties of graphene-derived membranes introduce them as appropriate candidates for gas separation and gas molecular-sieving processes in nanoscale dimensions. The current effort has focused on two issues, including the review of the most newly progression on drilling holes in single graphene membranes for making ultrathin membranes for gas separation, and studying functionalized nanoporous sheet and graphene-derived membranes, including doped graphene, graphene oxide, fluorographene, and reduced graphene oxide from theoretical perspectives for making functional coatings for nano ultrafiltration for gas separation. We investigated the basic mechanism of separation by membranes derived from graphene and relevant possible applications. Functionalized nanoporous membranes as novel approach are characterized by low energy cost in realizing high throughput molecular-sieving separation.

  5. Large-eddy simulation of separation and reattachment of a flat plate turbulent boundary layer

    KAUST Repository

    Cheng, W.

    2015-11-11

    © 2015 Cambridge University Press. We present large-eddy simulations (LES) of separation and reattachment of a flat-plate turbulent boundary-layer flow. Instead of resolving the near wall region, we develop a two-dimensional virtual wall model which can calculate the time- and space-dependent skin-friction vector field at the wall, at the resolved scale. By combining the virtual-wall model with the stretched-vortex subgrid-scale (SGS) model, we construct a self-consistent framework for the LES of separating and reattaching turbulent wall-bounded flows at large Reynolds numbers. The present LES methodology is applied to two different experimental flows designed to produce separation/reattachment of a flat-plate turbulent boundary layer at medium Reynolds number Reθ based on the momentum boundary-layer thickness θ. Comparison with data from the first case at demonstrates the present capability for accurate calculation of the variation, with the streamwise co-ordinate up to separation, of the skin friction coefficient, Reθ, the boundary-layer shape factor and a non-dimensional pressure-gradient parameter. Additionally the main large-scale features of the separation bubble, including the mean streamwise velocity profiles, show good agreement with experiment. At the larger Reθ = 11000 of the second case, the LES provides good postdiction of the measured skin-friction variation along the whole streamwise extent of the experiment, consisting of a very strong adverse pressure gradient leading to separation within the separation bubble itself, and in the recovering or reattachment region of strongly-favourable pressure gradient. Overall, the present two-dimensional wall model used in LES appears to be capable of capturing the quantitative features of a separation-reattachment turbulent boundary-layer flow at low to moderately large Reynolds numbers.

  6. Simulation codes of chemical separation process of spent fuel reprocessing. Tool for process development and safety research

    International Nuclear Information System (INIS)

    Asakura, Toshihide; Sato, Makoto; Matsumura, Masakazu; Morita, Yasuji

    2005-01-01

    This paper reviews the succeeding development and utilization of Extraction System Simulation Code for Advanced Reprocessing (ESSCAR). From the viewpoint of development, more tests with spent fuel and calculations should be performed with better understanding of the physico-chemical phenomena in a separation process. From the viewpoint of process safety research on fuel cycle facilities, it is important to know the process behavior of a key substance; being highly reactive but existing only trace amount. (author)

  7. Optimization and simulation of tandem column supercritical fluid chromatography separations using column back pressure as a unique parameter.

    Science.gov (United States)

    Wang, Chunlei; Tymiak, Adrienne A; Zhang, Yingru

    2014-04-15

    Tandem column supercritical fluid chromatography (SFC) has demonstrated to be a useful technique to resolve complex mixtures by serially coupling two columns of different selectivity. The overall selectivity of a tandem column separation is the retention time weighted average of selectivity from each coupled column. Currently, the method development merely relies on extensive screenings and is often a hit-or-miss process. No attention is paid to independently adjust retention and selectivity contributions from individual columns. In this study, we show how tandem column SFC selectivity can be optimized by changing relative dimensions (length or inner diameter) of the coupled columns. Moreover, we apply column back pressure as a unique parameter for SFC optimization. Continuous tuning of tandem column SFC selectivity is illustrated through column back pressure adjustments of the upstream column, for the first time. In addition, we show how and why changing coupling order of the columns can produce dramatically different separations. Using the empirical mathematical equation derived in our previous study, we also demonstrate a simulation of tandem column separations based on a single retention time measurement on each column. The simulation compares well with experimental results and correctly predicts column order and back pressure effects on the separations. Finally, considerations on instrument and column hardware requirements are discussed.

  8. Secondary flows occurring in a whirlpool separator – A study of phenomena – observation, simulation and measurements

    Directory of Open Access Journals (Sweden)

    Jakubowski Marek

    2015-09-01

    Full Text Available The whirlpool separator, used for hot trub separation, is prevalent in the brewing industry. It is a kind of a hydrocyclone inside of which a tea leaf effect occurs, which is sediment accumulation into a cone shape at the central part of the tank’s bottom. This manner of sediment accumulation is caused by the secondary flow occurring in the so-called Ekman boundary layer. This article is a summary of the research, which has been conducted for many years and involved observation, simulation and experimental research on the recognition and formation of the secondary flow accumulating the sediment cone. Secondary flows occurring in a whirlpool were identified through CFD simulation and PIV experiments, and are presented in this paper. Based on their location and direction, an attempt to determine their impact on the separation process taking place in the whirlpool has been made. The secondary flow identification methods proposed in this paper can be successfully applied in other solutions, e. g. structural ones, which involve rotational-flow-based separation.

  9. Recent progress in molecular simulation of nanoporous graphene membranes for gas separation

    Science.gov (United States)

    Fatemi, S. Mahmood; Baniasadi, Aminreza; Moradi, Mahrokh

    2017-07-01

    If an ideal membrane for gas separation is to be obtained, the following three characteristics should be considered: the membrane should be as thin as possible, be mechanically robust, and have welldefined pore sizes. These features will maximize its solvent flux, preserve it from fracture, and guarantee its selectivity. Graphene is made up of a hexagonal honeycomb lattice of carbon atoms with sp 2 hybridization state forming a one-atom-thick sheet of graphite. Following conversion of the honeycomb lattices into nanopores with a specific geometry and size, a nanoporous graphene membrane that offers high efficiency as a separation membrane because of the ultrafast molecular permeation rate as a result of its one-atom thickness is obtained. Applications of nanoporous graphene membranes for gas separation have been receiving remarkably increasing attention because nanoporous graphene membranes show promising results in this area. This review focuses on the recent advances in nanoporous graphene membranes for applications in gas separation, with a major emphasis on theoretical works. The attractive properties of nanoporous graphene membranes introduce make them appropriate candidates for gas separation and gas molecular-sieving processes in nanoscale dimensions.

  10. Scale-separation scheme for simulating superfluid turbulence: Kelvin-Wave cascade

    International Nuclear Information System (INIS)

    Kozik, Evgeny; Svistunov, Boris

    2005-01-01

    A Kolmogorov-type cascade of Kelvin waves--the distortion waves on vortex lines--plays a key part in the relaxation of superfluid turbulence at low temperatures. We propose an efficient numeric scheme for simulating the Kelvin-wave cascade on a single vortex line. This idea is likely to be generalizable for a full-scale simulation of different regimes of superfluid turbulence. With the new scheme, we are able to unambiguously resolve the cascade spectrum exponent, and thus to settle the controversy between recent simulations of Vinen, Tsubota, and Mitani [Phys. Rev. Lett. 91, 135301 (2003)] and recently developed analytic theory [Phys. Rev. Lett. 92, 035301 (2004)

  11. Prediction and evaluation method of wind environment in the early design stage using BIM-based CFD simulation

    International Nuclear Information System (INIS)

    Lee, Sumi; Song, Doosam

    2010-01-01

    Drastic urbanization and manhattanization are causing various problems in wind environment. This study suggests a CFD simulation method to evaluate wind environment in the early design stage of high-rise buildings. The CFD simulation of this study is not a traditional in-depth simulation, but a method to immediately evaluate wind environment for each design alternative and provide guidelines for design modification. Thus, the CFD simulation of this study to evaluate wind environments uses BIM-based CFD tools to utilize building models in the design stage. This study examined previous criteria to evaluate wind environment for pedestrians around buildings and selected evaluation criteria applicable to the CFD simulation method of this study. Furthermore, proper mesh generation method and CPU time were reviewed to find a meaningful CFD simulation result for determining optimal design alternative from the perspective of wind environment in the design stage. In addition, this study is to suggest a wind environment evaluation method through a BIM-based CFD simulation.

  12. Chemical analysis of simulated high level waste glasses to support stage III sulfate solubility modeling

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-17

    The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been a limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.

  13. Simulation calculations for a catalytic exchange/cryogenic distillation hydrogen isotope separation process

    International Nuclear Information System (INIS)

    Rodman, M.; Howard, D.W.

    1984-01-01

    Some of the aspects of the optimization and simulation calculations for the Moderator Detritiation Plant thay may be applicable to other processes are described. The FORTRAN optimization program and the CPES and PROCESS distillation calculation are covered

  14. Toxicity of effluents from gasoline stations oil-water separators to early life stages of zebrafish Danio rerio.

    Science.gov (United States)

    Alves, Romulo Nepomuceno; Mariz, Célio Freire; Paulo, Driele Ventura de; Carvalho, Paulo S M

    2017-07-01

    Used petroleum hydrocarbons and gasoline stations runoff are significant sources of polycyclic aromatic hydrocarbons (PAHs) to aquatic ecosystems. Samples of the final effluent of oil-water-separators were collected at gasoline stations in the metropolitan region of Recife, Brazil, before release to sewage or rainwater systems. Effluent soluble fractions (ESF) were prepared and bioassays were performed according to the Fish Embryo Toxicity Test. The test involved exposing zebrafish Danio rerio embryos to dilutions of the ESFs for 96 h, with daily examination of lethality and sublethal morphological effects integrated through the General Morphology Score (GMS), based on the achievement of developmental hallmarks. Frequencies of abnormalities were recorded after exposures. ESF LC50-96h (lethal concentration to 50% of exposed embryos) in the most toxic effluent achieved 8.9% (v/v), equivalent to 11 μg phenanthrene equivalents L -1 . GMS scores indicated significantly delayed embryo-larval development at ESF dilutions of 10% and 20% from effluents of all gas stations. Major abnormalities detected after the 96 h exposure included the presence of a yolk sac not fully absorbed coupled with the lack of an inflated swim bladder, lack of both pectoral fins, and the failure to develop a protruding mouth. Effective equivalent PAH concentrations that induce a 50% frequency of larvae without an inflated swim bladder (EC50) were 4.9 μg phenanthrene L -1 , 21.8 μg naphthalene L -1 , and 34.1 μg chrysene L -1 . This study shows that PAHs in ESFs from gas stations oil water separators are toxic to zebrafish, contributing to the toxicity of urban storm waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Staged pyrolysis, a process for chemical separation of waste plastics; Gestufte Pyrolyse als Verfahrensprinzip zur chemischen Auftrennung von Kunststoffgemischen

    Energy Technology Data Exchange (ETDEWEB)

    Hornung, A.; Hornung, U.; Schoeneberger, A.; Weichmann, J. [Kaiserslautern Univ. (Germany). Fachbereich Chemie; Bockhorn, H. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Chemische Technik

    1996-12-31

    It is shown that staged pyrolysis of mixed plastics (polystyrene, polyethylene, polyvinyl chloride, polyamide 6) can be carried out in spherical recirculation reactors or in cascades of spherical recirculation reactors at exact temperature levels, and that the times of residue and reaction temperatures of laboratory systems can be calculated from the formal kinetic parameters obtained in nonisothermal and isothermal investigations. (orig) [Deutsch] Es konnte gezeigt werden, dass das Prinzip der stufenweisen Pyrolyse von Kunststoffgemischen (Polystyrol, Polyethylen, Polyvinylchlorid bzw. Polyamid 6) im Kugelkreislaufreaktor und der Kaskade aus Kugelkreislaufreaktoren unter Einhaltung der exakten Temperaturniveaus realisierbar ist und die Auslegung der Laboranlage hinsichtlich der Verweilzeiten und Temperaturniveaus mit Hilfe der formalkinetischen Parameter aus nicht-isothermen und isothermen Untersuchungen moeglich ist. (orig)

  16. Gas-phase simulated moving bed: Propane/propylene separation on 13X zeolite.

    Science.gov (United States)

    Martins, Vanessa F D; Ribeiro, Ana M; Plaza, Marta G; Santos, João C; Loureiro, José M; Ferreira, Alexandre F P; Rodrigues, Alírio E

    2015-12-04

    In the last years several studies were carried out in order to separate gas mixtures by SMB technology; however, this technology has never been implemented on an industrial scale. In the present work, a gas phase SMB bench unit was built and tested for the separation of propane and propylene mixtures, using 13X zeolite extrudates as adsorbent and isobutane as desorbent. Three experiments were performed to separate propane/propylene by gas phase SMB in the bench scale unit with a 4-2-2 configuration, i.e., open loop circuit by suppressing section IV (desorbent regeneration followed by a recycle). Consequently, all the experiments were conducted using an external supply of pure isobutane as desorbent. Parameters such as switching time, extract and raffinate stream flow rates were changed to improve the efficiency of the process. Experimental results have shown that it is feasible to separate propylene from propane by gas phase SMB at a bench scale and that this process is a potential candidate to replace the conventional technologies for the propane/propylene separation. The performance parameters obtained are very promising for future development of this technology, since propylene was obtained in the extract stream with a purity of 99.93%, a recovery of 99.51%, and a productivity of [Formula: see text] . Propane was obtained in the raffinate stream with a purity of 98.10%, a recovery of 99.73% and a productivity of [Formula: see text] . The success of the above mentioned bench scale tests is a big step for the future implementation of this technology in a larger scale. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. URANS simulations of separated flow with stall cells over an NREL S826 airfoil

    Science.gov (United States)

    Sarlak, H.; Nishino, T.; Sørensen, J. N.

    2016-06-01

    A series of wind tunnel measurements and oil flow visualization was recently carried out at the Technical University of Denmark in order to investigate flow characteristics over a 14% thick NREL S826 airfoil at low Reynolds numbers. This paper aims at presenting numerical simulations of the same airfoil using unsteady Reynolds-averaged Navier-Stokes (URANS) approach. Results of the simulations are demonstrated in terms of mean flow velocity, lift and drag, as well as pressure distribution, and validated against available experimental data. The simulations are carried out with a wide computational domain (with a span-to-chord ratio of 5) and it is illustrated that the URANS approach is capable of predicting 3D spanwise structures, known as stall cells.

  18. Rapid selective separation of americium/curium from simulated nuclear forensic matrices using triazine ligands

    Energy Technology Data Exchange (ETDEWEB)

    Higginson, Matthew A.; Livens, Francis R.; Heath, Sarah L. [Manchester Univ. (United Kingdom). Centre for Radiochemistry Research; Thompson, Paul; Marsden, Olivia J. [AWE, Aldermaston, Reading (United Kingdom); Harwood, Laurence M.; Hudson, Michael J. [Reading Univ. (United Kingdom). Dept. of Chemistry; Lewis, Frank W. [Reading Univ. (United Kingdom). Dept. of Chemistry; Northumbria Univ., Newcastle upon Tyne (United Kingdom). Dept. of Chemical and Forensic Sciences

    2015-07-01

    In analysis of complex nuclear forensic samples containing lanthanides, actinides and matrix elements, rapid selective extraction of Am/Cm for quantification is challenging, in particular due the difficult separation of Am/Cm from lanthanides. Here we present a separation process for Am/Cm(III) which is achieved using a combination of AG1-X8 chromatography followed by Am/Cm extraction with a triazine ligand. The ligands tested in our process were CyMe{sub 4}-BTPhen, CyMe{sub 4}-BTBP, CA-BTP and CA-BTPhen. Our process allows for purification and quantification of Am and Cm (recoveries 80% - 100%) and other major actinides in < 2 d without the use of multiple columns or thiocyanate. The process is unaffected by high level Ca(II)/Fe(III)/Al(III) (10 mg mL{sup -1}) and thus requires little pre-treatment of samples.

  19. Modulator Dynamics Shape the Design Space for Stepwise-Elution Simulated Moving Bed Chromatographic Separations.

    Science.gov (United States)

    Wayne, Chris J; Velayudhan, Ajoy

    2018-03-31

    For proteins and other biological macromolecules, SMB chromatography is best operated non-isocratically. However, traditional modes of non-isocratic SMB operation generate significant mobile-phase modulator dynamics. The mechanisms by which these modulator dynamics affect a separation's success, and thus frame the design space, have yet to be explained quantitatively. Here, the dynamics of the modulator (e.g. salts in ion exchange and hydrophobic interaction chromatography) are explicitly accounted for. This leads to the elucidation of two new design constraints, presented as dimensionless numbers, which quantify the effects of the modulator phenomena and thus predict the success of a non-isocratic SMB separation. Consequently, these two new design constraints re-define the SMB design space. Computational and experimental studies at the boundaries of this design space corroborate the theoretical predictions. The design of efficient and robust operating conditions through use of the new design space is also demonstrated. This article is protected by copyright. All rights reserved.

  20. Computer simulation of phase separation and ordering processes in low-dimensional systems

    DEFF Research Database (Denmark)

    Mouritsen, O.G.; Shah, P.J.; Vitting Andersen, J.

    1991-01-01

    on the nature of the conservation laws in effect. Atomic and molecular overlayers on solid surfaces and weakly-coupled atomic layers of certain three-dimensional crystals constitute a particularly suitable class of systems for studying fundamental aspects of ordering dynamics and phase separation in two...... dimensions since these systems provide a richness of ordering symmetries and degeneracies as well as they obey different conservation laws. Specific systems dealt with include the chemisorption systems O/W(110) and O/W(112), and oxygen layers in the basal CuO-planes of high-T(c) superconductors of the YBa2Cu......An account is given of recent activity in the field of dynamics of phase separation and ordering processes in two-dimensional statistical mechanical models. The fundamental questions of the dynamics involve the form of the growth law, the value of the growth exponent, the dynamical scaling...

  1. Simulation of a multi-stage adiabatic reactor with inter-stage quenching for dimethyl ether synthesis

    Directory of Open Access Journals (Sweden)

    Bai Ziyang

    2014-01-01

    Full Text Available Adiabatic fixed-bed reactor has proven commercially successful in large scale production of catalytic dehydration of methanol to dimethyl ether. A one dimensional pseudo-homogeneous model of an industrial reactor of dimethyl ether synthesis has been established. To verify the proposed model, the simulation results have been compared to available data from an industrial reactor. A good agreement has been found between them. The distribution of the catalyst bed temperature and concentration of each component was obtained under conditions of inlet temperature 260°C, reaction pressure 1.2MPa and gaseous hourly space velocity 950.7 h-1. With inlet catalyst bed temperature 240-280°C, operating pressure 0.6-1.8MPa and gaseous hourly space velocity 831.8-1069.5 h-1, the influence of these reaction conditions on temperature distribution of the reactor catalytic bed, outlet methanol conversion and the dimethyl ether yield were calculated. The results show that, with the rise of inlet temperature (240-280°C and operating pressure (0.6-1.8MPa, the outlet conversion of methanol, the hot spot temperature and the DME yield increased. The increase of gaseous hourly space velocity (831.8-1069.5 h-1 leads to a decrease in the hot spot temperature of catalytic bed and the outlet conversion of methanol. But the DME yield rise initially and then descend.

  2. Numerical simulation of a Rotating Detonation with a realistic injector designed for separate supply of gaseous hydrogen and oxygen

    Science.gov (United States)

    Gaillard, T.; Davidenko, D.; Dupoirieux, F.

    2017-12-01

    This paper presents numerical results for a Rotating Detonation (RD) propagating in a layer of combustible mixture, created by injection of gaseous hydrogen and oxygen. 3D Large Eddy Simulations (LES) of a reacting flow have been performed in a domain of planar geometry in order to eliminate possible effects of the chamber curvature. First, the results for a 2D case with uniformly distributed premixed injection are presented to characterize the RD propagation under the most idealized conditions. Then a 3D concept is introduced for the injector composed of a series of injection elements. The RD propagation is simulated under the conditions of premixed and separate injection of the propellants at globally stoichiometric proportions. The case of separate propellant injection is the most realistic one. The computational results, represented by instantaneous and averaged flowfields, are analyzed to characterize the flowfield and the conditions of RD propagation. This analysis allows identifying the effects due to two major factors: the injection through discrete holes with respect to the distributed one and the separate propellant feeding with respect to the premixed one. Macroscopic quantities, such as the RD propagation speed, mean chamber pressure, average parameters of the mixture, and mixing efficiency are evaluated and compared in order to characterize the studied effects.

  3. Simulated Target Preparation and Separation of Cd (II) - In (III) Matrices Using 8-Hydroxyquinoline Reagent for Producing Indium - III Radioisotope

    International Nuclear Information System (INIS)

    Sunarhadijoso Soenarjo; Swasono R Tamat; Lukiyawati; Lintang Maharani

    2002-01-01

    The potency of production and application of 111 In in Indonesia is not supported yet by capability in required processing technology. The presented paper is a preliminary study on processing technology of 111 In production from 112 Cd target covering simulated target preparation and separation of Cd(II)-In(III) matrices. The target preparation was performed by means of electroplating of CdSO 4 solution prepared from reaction of CdO and sulphuric acid. The separation of Cd(II)-In(III) matrices was proceeded by means of solvent extraction in the presence of 8-hydroxyquinoline as In(III)-complexing agent. The Cd-electroplating deposit was satisfactorily found by using 40-60 mA currents with an electroplating time of 5-7 hours. Simulated matrix solution containing mixture of Cd(II) and In(III) was extracted into chloroform with the presence of 8-hydroxyquinoline. The chloroform phase being assumed to contain In(III)-8-hydroxyquinoline complex was then re-extracted with 1 M HCl or saline solution. Each extraction fraction was spectrophotometrically identified in the region of 200-400 nm. From the resulting absorption spectra, it can be shown that the In(III) species is selectively separated from the Cd(II)-matrix. The use of saline in the re-extraction process is better then 1 M HCl solution due to solubility of 8-hydroxyquinoline in HCl. (author)

  4. Membrane separation study for methane-hydrogen gas mixtures by molecular simulations

    Directory of Open Access Journals (Sweden)

    T. Kovács

    2017-06-01

    Full Text Available Direct simulation results for stationary gas transport through pure silica zeolite membranes (MFI, LTA and DDR types are presented using a hybrid, non-equilibrium molecular dynamics simulation methodology introduced recently. The intermolecular potential models for the investigated CH_4 and H_2 gases were taken from literature. For different zeolites, the same atomic (Si and O interaction parameters were used, and the membranes were constructed according to their real (MFI, LTA, or DDR crystal structures. A realistic nature of the applied potential parameters was tested by performing equilibrium adsorption simulations and by comparing the calculated results with the data of experimental adsorption isotherms. The results of transport simulations carried out at 25°C and 125°C, and at 2.5, 5 or 10 bar clearly show that the permeation selectivities of CH_4 are higher than the corresponding permeability ratios of pure components, and significantly differ from the equilibrium selectivities in mixture adsorptions. We experienced a transport selectivity in favor of CH_4 in only one case. A large discrepancy between different types of selectivity data can be attributed to dissimilar mobilities of the components in a membrane, their dependence on the loading of a membrane, and the unlike adsorption preferences of the gas molecules.

  5. URANS simulations of separated flow with stall cells over an NREL S826 airfoil

    DEFF Research Database (Denmark)

    Sarlak Chivaee, Hamid; Nishino, T.; Sørensen, Jens Nørkær

    2016-01-01

    A series of wind tunnel measurements and oil flow visualization was recently carried out at the Technical University of Denmark in order to investigate flow characteristics over a 14% thick NREL S826 airfoil at low Reynolds numbers. This paper aims at presenting numerical simulations of the same ...

  6. Intermittent simulated moving bed chromatography: 3. Separation of Tröger's base enantiomers under nonlinear conditions.

    Science.gov (United States)

    Katsuo, Shigeharu; Langel, Christian; Sandré, Anne-Laure; Mazzotti, Marco

    2011-12-30

    One of the modified simulated moving bed (SMB) processes, the intermittent SMB (I-SMB) process, has been recently analyzed theoretically [1] and its superior performance compared to the conventional SMB process has been demonstrated at a rather low total feed concentration through experiments and simulations [2]. This work shows that the I-SMB process outperforms the conventional SMB process also at high feed concentration where the species are clearly subject to a nonlinear adsorption isotherm. In the case of the separation of the Tröger's base's enantiomers in ethanol on ChiralPak AD, the two processes operated in a six-column 1-2-2-1 configuration (one column in sections 1 and 4 and two columns in sections 2 and 3) and in a four-column 1-1-1-1 configuration (one column in each section) are compared at high feed concentration through both experiments and simulations. Even under nonlinear conditions the four column I-SMB process can successfully separate the two enantiomers achieving purity levels as high as the two six column processes and exhibiting better productivity. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Carbon dioxide and methane transport in DDR zeolite: insights from molecular simulations into carbon dioxide separations in small pore zeolites.

    Science.gov (United States)

    Jee, Sang Eun; Sholl, David S

    2009-06-10

    The silica zeolite DDR is a strong candidate for separations of CO(2)/CH(4) because of the narrow windows that control molecular transport inside the material's pores. We have used molecular simulations to describe diffusion of CO(2) and CH(4) inside DDR pores. Our simulations introduce a new force-field for this system that for the first time gives results that are consistent with experimental measurements of single-component adsorption and diffusion. Diffusivities obtained from previous simulations greatly overestimated the transport rates of CH(4) and, to a lesser extent, CO(2). Because CH(4) diffuses extremely slowly in DDR, we applied a transition state theory-based kinetic Monte Carlo scheme to accurately describe this diffusion. The most important observation from our calculations is that the characteristics of CO(2)/CH(4) diffusion in DDR are very different from the usual situation in nanoporous materials, where the presence of a slowly diffusing species retards transport rates of a more rapidly diffusing species. In DDR, we show that CO(2) diffusion rates are only weakly affected by the presence of CH(4), despite the very slow diffusion of the latter molecules. The physical origins of this unusual behavior are explained by analyzing the adsorption sites and diffusion mechanism for each species. Our finding suggests DDR membranes are favorable for CO(2)/CH(4) separations and that similar properties may exist for other 8MR zeolites.

  8. Blood–plasma separation in Y-shaped bifurcating microfluidic channels: a dissipative particle dynamics simulation study

    International Nuclear Information System (INIS)

    Li, Xuejin; Karniadakis, George Em; Popel, Aleksander S

    2012-01-01

    The motion of a suspension of red blood cells (RBCs) flowing in a Y-shaped bifurcating microfluidic channel is investigated using a validated low-dimensional RBC model based on dissipative particle dynamics. Specifically, the RBC is represented as a closed torus-like ring of ten colloidal particles, which leads to efficient simulations of blood flow in microcirculation over a wide range of hematocrits. Adaptive no-slip wall boundary conditions were implemented to model hydrodynamic flow within a specific wall structure of diverging three-dimensional microfluidic channels, paying attention to controlling density fluctuations. Plasma skimming and the all-or-nothing phenomenon of RBCs in a bifurcating microfluidic channel have been investigated in our simulations for healthy and diseased blood, including the size of a cell-free layer on the daughter branches. The feed hematocrit level in the parent channel has considerable influence on blood–plasma separation. Compared to the blood–plasma separation efficiencies of healthy RBCs, malaria-infected stiff RBCs (iRBCs) have a tendency to travel into the low flow-rate daughter branch because of their different initial distribution in the parent channel. Our simulation results are consistent with previously published experimental results and theoretical predictions. (paper)

  9. Taurus II Stage Test Simulations: Using Large-Scale CFD Simulations to Provide Critical Insight into Plume Induced Environments During Design

    Science.gov (United States)

    Struzenberg, L. L.; West, J. S.

    2011-01-01

    This paper describes the use of targeted Loci/CHEM CFD simulations to evaluate the effects of a dual-engine first-stage hot-fire test on an evolving integrated launch pad/test article design. This effort was undertaken as a part of the NESC Independent Assessment of the Taurus II Stage Test Series. The underlying conceptual model included development of a series of computational models and simulations to analyze the plume induced environments on the pad, facility structures and test article. A pathfinder simulation was first developed, capable of providing quick-turn around evaluation of plume impingement pressures on the flame deflector. Results from this simulation were available in time to provide data for an ongoing structural assessment of the deflector. The resulting recommendation was available in a timely manner and was incorporated into construction schedule for the new launch stand under construction at Wallops Flight Facility. A series of Reynolds-Averaged Navier-Stokes (RANS) quasi-steady simulations representative of various key elements of the test profile was performed to identify potential concerns with the test configuration and test profile. As required, unsteady Hybrid-RANS/LES simulations were performed, to provide additional insight into critical aspects of the test sequence. Modifications to the test-specific hardware and facility structures thermal protection as well as modifications to the planned hot-fire test profile were implemented based on these simulation results.

  10. Simulation and modeling of the processes in the isotopic exchange column of a cryogenic pilot plant for tritium separation

    International Nuclear Information System (INIS)

    Retevoi, Carmen Maria; Stefan, Liviu; Balteanu, Ovidiu; Stefan, Iulia; Bornea, Anisia; Salamon, Peter

    2002-01-01

    The technology developed at the Institute of Cryogenics and Isotope Separations is based on catalytic isotope exchange between water and hydrogen gas both carrying various isotopes of hydrogen: normal hydrogen, deuterium, and tritium. This isotope exchange is followed by cryogenic distillation separating the various isotopes of hydrogen gas. The detritiation process was simulated using as working fluids water with a small content of deuterium and a gaseous mixture of hydrogen and deuterium. The mathematical model and the measured parameters permitted to compute the speed constants of the isotopic exchange by distillation and catalytic action, respectively, for deuterium and tritium. Also for monitoring the isotopic exchange column careful control of the temperature is necessary. To ensure that we made an automation system with data acquisition and control which provides all the data for analysis. (authors)

  11. Nonlinear model predictive control applied to the separation of praziquantel in simulated moving bed chromatography.

    Science.gov (United States)

    Andrade Neto, A S; Secchi, A R; Souza, M B; Barreto, A G

    2016-10-28

    An adaptive nonlinear model predictive control of a simulated moving bed unit for the enantioseparation of praziquantel is presented. A first principle model was applied at the proposed purity control scheme. The main concern about this kind of model in a control framework is in regard to the computational effort to solve it; however, a fast enough solution was achieved. In order to evaluate the controller's performance, several cases were simulated, including external pumps and switching valve malfunctions. The problem of plant-model mismatch was also investigated, and for that reason a parameter estimation step was introduced in the control strategy. In every studied scenario, the controller was able to maintain the purity levels at their set points, which were set to 99% and 98.6% for extract and raffinate, respectively. Additionally, fast responses and smooth actuation were achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Surfactant-nanotube interactions in water and nanotube separation by diameter: atomistic simulations

    Science.gov (United States)

    Carvalho, E. J. F.; Dos Santos, M. C.

    2010-05-01

    A non-destructive sorting method to separate single-walled carbon nanotubes (SWNTs) by diameter was recently proposed. By this method, SWNTs are suspended in water by surfactant encapsulation and the separation is carried out by ultracentrifugation in a density gradient. SWNTs of different diameters are distributed according to their densities along the centrifuge tube. A mixture of two anionic surfactants, namely sodium dodecylsulfate (SDS) and sodium cholate (SC), presented the best performance in discriminating nanotubes by diameter. Unexpectedly, small diameter nanotubes are found at the low density part of the centrifuge tube. We present molecular dynamics studies of the water-surfactant-SWNT system to investigate the role of surfactants in the sorting process. We found that surfactants can actually be attracted towards the interior of the nanotube cage, depending on the relationship between the surfactant radius of gyration and the nanotube diameter. The dynamics at room temperature showed that, as the amphiphile moves to the hollow cage, water molecules are dragged together, thereby promoting the nanotube filling. The resulting densities of filled SWNT are in agreement with measured densities.

  13. Application of retention modelling to the simulation of separation of organic anions in suppressed ion chromatography.

    Science.gov (United States)

    Zakaria, Philip; Dicinoski, Greg W; Ng, Boon Khing; Shellie, Robert A; Hanna-Brown, Melissa; Haddad, Paul R

    2009-09-18

    The ion-exchange separation of organic anions of varying molecular mass has been demonstrated using ion chromatography with isocratic, gradient and multi-step eluent profiles on commercially available columns with UV detection. A retention model derived previously for inorganic ions and based solely on electrostatic interactions between the analytes and the stationary phase was applied. This model was found to accurately describe the observed elution of all the anions under isocratic, gradient and multi-step eluent conditions. Hydrophobic interactions, although likely to be present to varying degrees, did not limit the applicability of the ion-exchange retention model. Various instrumental configurations were investigated to overcome problems associated with the use of organic modifiers in the eluent which caused compatibility issues with the electrolytically derived, and subsequently suppressed, eluent. The preferred configuration allowed the organic modifier stream to bypass the eluent generator, followed by subsequent mixing before entering the injection valve and column. Accurate elution prediction was achieved even when using 5-step eluent profiles with errors in retention time generally being less than 1% relative standard deviation (RSD) and all being less than 5% RSD. Peak widths for linear gradient separations were also modelled and showed good agreement with experimentally determined values.

  14. Groundwater flow simulation of the Savannah River Site general separations area

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bagwell, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bennett, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-07

    The most recent groundwater flow model of the General Separations Area, Savannah River Site, is referred to as the “GSA/PORFLOW” model. GSA/PORFLOW was developed in 2004 by porting an existing General Separations Area groundwater flow model from the FACT code to the PORFLOW code. The preceding “GSA/FACT” model was developed in 1997 using characterization and monitoring data through the mid-1990’s. Both models were manually calibrated to field data. Significantly more field data have been acquired since the 1990’s and model calibration using mathematical optimization software has become routine and recommended practice. The current task involved updating the GSA/PORFLOW model using selected field data current through at least 2015, and use of the PEST code to calibrate the model and quantify parameter uncertainty. This new GSA groundwater flow model is named “GSA2016” in reference to the year in which most development occurred. The GSA2016 model update is intended to address issues raised by the DOE Low-Level Waste (LLW) Disposal Facility Federal Review Group (LFRG) in a 2008 review of the E-Area Performance Assessment, and by the Nuclear Regulatory Commission in reviews of tank closure and Saltstone Disposal Facility Performance Assessments.

  15. Nonlinear dynamic behaviors and control based on simulation of high-purity heat integrated air separation column.

    Science.gov (United States)

    Fu, Yao; Liu, Xinggao

    2015-03-01

    In this paper, the dynamic behaviors on the basis of simulation for high-purity heat integrated air separation column (HIASC) are studied. A nonlinear generic model control (GMC) scheme is proposed based on the nonlinear behavior analyses of a HIASC process, and an adaptive generic model control (AGMC) scheme is further presented to correct the model parameters online. Related internal model control (IMC) scheme and multi-loop PID (M-PID) scheme are also developed as the comparative base. The comparative researches are carried out among these linear and nonlinear control schemes in detail. The simulation research results show that the proposed AGMC schemes present advantages in both servo control and regulatory control for the high-purity HIASC. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  16. Phase separation and near-critical fluctuations in two-component lipid membranes: Monte Carlo simulations on experimentally relevant scales

    International Nuclear Information System (INIS)

    Ehrig, Jens; Petrov, Eugene P; Schwille, Petra

    2011-01-01

    By means of lattice-based Monte Carlo simulations, we address the properties of two-component lipid membranes on the experimentally relevant spatial scales of the order of a micrometer and time intervals of the order of 1 s, using DMPC/DSPC lipid mixtures as a model system. Our large-scale simulations allowed us to obtain important results not reported previously in simulation studies of lipid membranes. We find that, for a certain range of lipid compositions, the phase transition from the fluid phase to the fluid-gel phase coexistence proceeds via near-critical fluctuations, whereas for other lipid compositions this phase transition has a quasi-abrupt character. In the presence of near-critical fluctuations, transient subdiffusion of lipid molecules is observed. These features of the system are stable with respect to perturbations in lipid interaction parameters used in our simulations. The line tension characterizing lipid domains in the fluid-gel coexistence region is found to be in the pN range. On approaching the critical point, the line tension, the inverse correlation length of fluid-gel spatial fluctuations and the corresponding inverse order parameter susceptibility of the membrane vanish. All these results are in agreement with recent experimental findings for model lipid membranes. Our analysis of the domain coarsening dynamics after an abrupt quench of the membrane to the fluid-gel coexistence region reveals that lateral diffusion of lipids plays an important role in the fluid-gel phase separation process.

  17. The application of neutral network integrated with genetic algorithm and simulated annealing for the simulation of rare earths separation processes by the solvent extraction technique using EHEHPA agent

    International Nuclear Information System (INIS)

    Tran Ngoc Ha; Pham Thi Hong Ha

    2003-01-01

    In the present work, neutral network has been used for mathematically modeling equilibrium data of the mixture of two rare earth elements, namely Nd and Pr with PC88A agent. Thermo-genetic algorithm based on the idea of the genetic algorithm and the simulated annealing algorithm have been used in the training procedure of the neutral networks, giving better result in comparison with the traditional modeling approach. The obtained neutral network modeling the experimental data is further used in the computer program to simulate the solvent extraction process of two elements Nd and Pr. Based on this computer program, various optional schemes for the separation of Nd and Pr have been investigated and proposed. (author)

  18. Numerical simulations of single and multi-staged injection of H2 in a supersonic scramjet combustor

    Directory of Open Access Journals (Sweden)

    L. Abu-Farah

    2014-12-01

    Full Text Available Computational fluid dynamics (CFD simulations of a single staged injection of H2 through a central wedge shaped strut and a multi-staged injection through wall injectors are carried out by using Ansys CFX-12 code. Unstructured tetrahedral grids for narrow channel and quarter geometries of the combustor are generated by using ICEM CFD. Steady three-dimensional (3D Reynolds-averaged Navier-stokes (RANS simulations are carried out in the case of no H2 injection and compared with the simulations of single staged pilot and/or main H2 injections and multistage injection. Shear stress transport (SST based on k-ω turbulent model is adopted. Flow field visualization (complex shock waves interactions and static pressure distribution along the wall of the combustor are predicted and compared with the experimental schlieren images and measured wall static pressures for validation. A good agreement is found between the CFD predicted results and the measured data. The narrow and quarter geometries of the combustor give similar results with very small differences. Multi-staged injections of H2 enhance the turbulent H2/air mixing by forming vortices and additional shock waves (bow shocks.

  19. Numerical simulations for the coal/oxidant distribution effects between two-stages for multi opposite burners (MOB) gasifier

    International Nuclear Information System (INIS)

    Unar, Imran Nazir; Wang, Lijun; Pathan, Abdul Ghani; Mahar, Rasool Bux; Li, Rundong; Uqaili, M. Aslam

    2014-01-01

    Highlights: • We simulated a double stage 3D entrained flow coal gasifier with multi-opposite burners. • The various reaction mechanisms have evaluated with experimental results. • The effects of coal and oxygen distribution between two stages on the performance of gasifier have investigated. • The local coal to oxygen ratio is affecting the overall efficiency of gasifier. - Abstract: A 3D CFD model for two-stage entrained flow dry feed coal gasifier with multi opposite burners (MOB) has been developed in this paper. At each stage two opposite nozzles are impinging whereas the two other opposite nozzles are slightly tangential. Various numerical simulations were carried out in standard CFD software to investigate the impacts of coal and oxidant distributions between the two stages of the gasifier. Chemical process was described by Finite Rate/Eddy Dissipation model. Heterogeneous and homogeneous reactions were defined using the published kinetic data and realizable k–ε turbulent model was used to solve the turbulence equations. Gas–solid interaction was defined by Euler–Lagrangian frame work. Different reaction mechanism were investigated first for the validation of the model from published experimental results. Then further investigations were made through the validated model for important parameters like species concentrations in syngas, char conversion, maximum inside temperature and syngas exit temperature. The analysis of the results from various simulated cases shows that coal/oxidant distribution between the stages has great influence on the overall performance of gasifier. The maximum char conversion was found 99.79% with coal 60% and oxygen 50% of upper level of injection. The minimum char conversion was observed 95.45% at 30% coal with 40% oxygen at same level. In general with oxygen and coal above or equal to 50% of total at upper injection level has shown an optimized performance

  20. Simulation of a process for the two-stage thermal conversion of biomass into the synthesis gas

    Science.gov (United States)

    Kosov, V. F.; Lavrenov, V. A.; Zaichenko, V. M.

    2015-11-01

    The paper presents results of simulation of a process for the two-stage thermal conversion of wood biomass into the synthesis gas. The first stage of process is pyrolysis of raw materials, the second stage is cracking of volatile pyrolysis products which blown through the char at a temperature of about 1000° C. Char is a porous biomass residue with carbon content about 90%. The simulation based on the results of experimental investigations of a pilot plant with capacity up to 50 kg of raw material per hour. The main result of simulation is estimation of an energy conversion efficiency of wood biomass into synthesis gas for three different operation modes. The first mode is conversion of biomass into fuel gas and char, and the char is not further used. The second mode is the same, but char used as fuel for producing heat for own demand of the process. The third mode includes gasification of char by means of water steam, aimed to obtaining an additional yield of synthesis gas. The simulation shown, that total efficiency of power plant was 17.1% in the first mode, 22.4% in the second mode and 22.6% in the third mode.

  1. Simulation of Multiphase Flow of the Oil-Water Separation in a Rotating Packed Bed for Oil Purification

    Directory of Open Access Journals (Sweden)

    Xiaojun Zhang

    2013-01-01

    particle contaminant, moisture and gas simultaneously. As the major unit of HIGEE, the RPB uses centrifugal force to intensify mass transfer. Because of the special structure of RPB, the hydraulic characteristics of the RPB are very important. In this study, the multiphase flow model in porous media of the RPB is presented, and the dynamical oil-water separation in the RPB is simulated using a commercial computational fluid dynamics code. The operating conditions and configuration on the hydraulic performance of the RPB are investigated. The results have indicated that the separation efficiency of HIGEE rotating oil purifier is predominantly affected by operating conditions and the configurations. The best inlet pressure is 0.002 MPa. When the liquid inlet is placed in the outside of the lower surface of RPB; oil outlet is placed in the upper surface, where it is near the rotation axis; and water outlet is placed in the middle of the RPB, where it is far away from the oil outlet, the separating efficiency is the best.

  2. Simulation and optimization of stable isotope 18O separation by cascade distillation

    International Nuclear Information System (INIS)

    Jiang Yongyue; Chen Yuyan; Qin Chuanjiang; Liu Yan; Gu Hongsen

    2011-01-01

    The research about started from the plan of four cascade towers design was carried. Firstly, the method of experiment design was using uniform design. Then the incidence formula with the method of binomial stepwise regression was gotten. Last, the optimal operation conditions were gotten by using the method of genetic algorithm. Considering comprehensive factors of drawn from feed rate and from flow rates between cascade column, conclusions were reached on the study of the impact on the abundance of the isotope 18 O. Finally, the incidence formula between the abundance of the isotope 18 O and four operating variables were gotten. Also the incidence formula between heat consumption of the isotope 18 O and four operating variables were gotten. Besides, single factor response diagram of four factors were shown at last. The results showed that the method of simulation and optimization could be applied to 18 O industrial design and would be popular in traditional distillation process to realize optimization design. (authors)

  3. A fast and accurate numerical method for solving simulated moving bed (SMB) chromatographic separation problems

    DEFF Research Database (Denmark)

    Lim, Young-il; Jørgensen, Sten Bay

    2003-01-01

    numerical solutions are obtained. Stable solutions are guaranteed if the Courant-Friedrichs-Lewy (CFL) condition is satisfied. The boundary condition and recycle flow treatments are much simpler than for the time integrator in the framework of the method of lines. Applying the CE/SE method for SMB......Solving simulated moving bed (SMB) chromatography models requires fast and accurate numerical techniques, since their system size computed is large due to multi-columns and multi-components, in addition the axial solution profiles contain steep moving fronts. The space-time conservation element....../solution element (CE/SE) method addressed in this study enforces both local and global flux conservation in space and time, and uses a simple stencil structure (two points at the previous time level and one point at the present time level) on staggered space-time grids. Thus, accurate and computationally efficient...

  4. Molecular Simulation of Ionic Polyimides and Composites with Ionic Liquids as Gas-Separation Membranes.

    Science.gov (United States)

    Abedini, Asghar; Crabtree, Ellis; Bara, Jason E; Turner, C Heath

    2017-10-24

    Polyimides are at the forefront of advanced membrane materials for CO 2 capture and gas-purification processes. Recently, ionic polyimides (i-PIs) have been reported as a new class of condensation polymers that combine structural components of both ionic liquids (ILs) and polyimides through covalent linkages. In this study, we report CO 2 and CH 4 adsorption and structural analyses of an i-PI and an i-PI + IL composite containing [C 4 mim][Tf 2 N]. The combination of molecular dynamics (MD) and grand canonical Monte Carlo (GCMC) simulations is used to compute the gas solubility and the adsorption performance with respect to the density, fractional free volume (FFV), and surface area of the materials. Our results highlight the polymer relaxation process and its correlation to the gas solubility. In particular, the surface area can provide meaningful guidance with respect to the gas solubility, and it tends to be a more sensitive indicator of the adsorption behavior versus only considering the system density and FFV. For instance, as the polymer continues to relax, the density, FFV, and pore-size distribution remain constant while the surface area can continue to increase, enabling more adsorption. Structural analyses are also conducted to identify the nature of the gas adsorption once the ionic liquid is added to the polymer. The presence of the IL significantly displaces the CO 2 molecules from the ligand nitrogen sites in the neat i-PI to the imidazolium rings in the i-PI + IL composite. However, the CH 4 molecules move from the imidazolium ring sites in the neat i-PI to the ligand nitrogen atoms in the i-PI + IL composite. These molecular details can provide critical information for the experimental design of highly selective i-PI materials as well as provide additional guidance for the interpretation of the simulated adsorption systems.

  5. CFD simulation of length to diameter ratio effects on the energy separation in a vortex tube

    Directory of Open Access Journals (Sweden)

    Bramo Reza Abdol

    2011-01-01

    Full Text Available The objective of the present computational fluid dynamics analysis is an attempt to investigate the effect of length to diameter ratio on the fluid flow characteristics and energy separation phenomenon inside the Ranque-Hilsch vortex tube. In this numerical study, performance of Ranque-Hilsch vortex tubes (RHVT, with length to diameter ratios (L/D of 8, 9.3, 10.5, 20.2, 30.7 and 35 with six straight nozzles was investigated. It includes generating better understanding of the effects of the stagnation point location on the performance of RHVT. It was found that the best performance was obtained when the ratio of vortex tube length to the diameter was 9.3 and also fort this case the stagnation point was found to be the farthest from the inlet. The results show that the closer distance to the hot end is produced the larger magnitude of the temperature difference. Computed results show good agreement with published experimental results.

  6. Staged abdominal closure with intramuscular tissue expanders and modified components separation technique of a giant incisional hernia after repair of a ruptured omphalocele

    Directory of Open Access Journals (Sweden)

    Yukihiro Tatekawa

    2016-07-01

    Full Text Available In patients with omphalocele, several different techniques are performed for repair of the abdominal wall defect. We present the case of a staged abdominal closure of a giant incisional hernia after repair of a ruptured omphalocele. At birth, skin flap coverage associated with silo formation occurred, but the abdominal wall defect remained, resulting in a giant abdominal hernia. To expand the layers of the abdominal wall, tissue expanders were placed between the bilateral internal oblique and transverses abdominis muscles. Postoperatively, a modified components separation technique was performed. The abdominal wall was closed in the midline. Upon closure of the skin in the midline, bilateral relaxing incisions were performed, covering the remaining defect with artificial dermis. At the age of one year and 7 months, the patient had no recurrent incisional hernia nor any wound complications.

  7. Numerical simulation of CO2 separation from gas mixtures in membrane modules: Effect of chemical absorbent

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Reza Razavi

    2016-01-01

    Full Text Available In this study, a mathematical model is proposed for prediction of CO2 absorption from N2/CO2 mixture by potassium threonate in a hollow-fiber membrane contactor (HFMC. CFD technique using numerical method of finite element was applied to solve the governing equations of model. Effect of different factors on CO2 absorption was analyzed and for investigation of absorbent type effect, functioning of potassium threonate was compared with diethanolamine (DEA. Axial and radial diffusion can be described with the two dimensional model established in this work. The obtained simulation results were compared with the reported experimental data to ensure accuracy of the model predictions. Comparison of model results with experimental data revealed that the developed model can well predict CO2 capture by potassium threonate in HFMCs. Increment of absorbent flow rate and concentration eventuate in enhancement of CO2 absorption. On the other hand, capture of CO2 will be reduced with increment of gas flow rate. According to the model results, potassium threonate can be considered as a more efficient absorbent as compared with DEA.

  8. Numerical Simulations of Flow Separation Control in Low-Pressure Turbines using Plasma Actuators

    Science.gov (United States)

    Suzen, Y. B.; Huang, P. G.; Ashpis, D. E.

    2007-01-01

    A recently introduced phenomenological model to simulate flow control applications using plasma actuators has been further developed and improved in order to expand its use to complicated actuator geometries. The new modeling approach eliminates the requirement of an empirical charge density distribution shape by using the embedded electrode as a source for the charge density. The resulting model is validated against a flat plate experiment with quiescent environment. The modeling approach incorporates the effect of the plasma actuators on the external flow into Navier Stokes computations as a body force vector which is obtained as a product of the net charge density and the electric field. The model solves the Maxwell equation to obtain the electric field due to the applied AC voltage at the electrodes and an additional equation for the charge density distribution representing the plasma density. The new modeling approach solves the charge density equation in the computational domain assuming the embedded electrode as a source therefore automatically generating a charge density distribution on the surface exposed to the flow similar to that observed in the experiments without explicitly specifying an empirical distribution. The model is validated against a flat plate experiment with quiescent environment.

  9. [A physiological development time-based simulation model for cotton development stages and square- and boll formation].

    Science.gov (United States)

    Ma, Fuyu; Cao, Weixing; Zhang, Lizhen; Zhu, Yan; Li, Shaokun; Zhou, Zhiguo; Li, Cundong; Xu, Lihua

    2005-04-01

    In this study, three cotton varieties (CRI 36, CRI 35 and CRI 41) were planted in Nanjing, Anyang, Baoding and Shihezi, respectively, in 2002, and the dynamic relationships between their development and environmental factors were analyzed. Based on this, a simulation model for cotton development stages and square-and boll development was built in terms of physiological development time (PDT). In calculating relative thermal effectiveness, the effect of diurnal temperature differences in different regions on cotton development was incorporated, and the enhancement of plastic mulching on air temperature was quantified. To simulate development stages, the initial fruiting node index (IFIN), sunlight duration factor (FSH), and solar radiation index on fruiting branch (IFBR) were introduced, besides earliness factor of a given genotype. The validation of the model with the data obtained from different years, ecological zones, genotypes, and cultivation practices indicated a high goodness of fitness between the simulated results and observed values. The root mean square error (RMSE) between simulated and observed days from sowing to emergence, emergence to squaring, anthesis to boll opening, and sowing to boll opening was 0.9, 2.2, 1.7, and 2.1 d, respectively, with a mean of 2.1 d, and in all plant sites, the RMSE between simulated and observed days from squaring to boll opening was 1.8-3.7 d, and that from squaring to opening was 4.6-5.8 d.

  10. One-stage individual participant data meta-analysis models: estimation of treatment-covariate interactions must avoid ecological bias by separating out within-trial and across-trial information.

    Science.gov (United States)

    Hua, Hairui; Burke, Danielle L; Crowther, Michael J; Ensor, Joie; Tudur Smith, Catrin; Riley, Richard D

    2017-02-28

    Stratified medicine utilizes individual-level covariates that are associated with a differential treatment effect, also known as treatment-covariate interactions. When multiple trials are available, meta-analysis is used to help detect true treatment-covariate interactions by combining their data. Meta-regression of trial-level information is prone to low power and ecological bias, and therefore, individual participant data (IPD) meta-analyses are preferable to examine interactions utilizing individual-level information. However, one-stage IPD models are often wrongly specified, such that interactions are based on amalgamating within- and across-trial information. We compare, through simulations and an applied example, fixed-effect and random-effects models for a one-stage IPD meta-analysis of time-to-event data where the goal is to estimate a treatment-covariate interaction. We show that it is crucial to centre patient-level covariates by their mean value in each trial, in order to separate out within-trial and across-trial information. Otherwise, bias and coverage of interaction estimates may be adversely affected, leading to potentially erroneous conclusions driven by ecological bias. We revisit an IPD meta-analysis of five epilepsy trials and examine age as a treatment effect modifier. The interaction is -0.011 (95% CI: -0.019 to -0.003; p = 0.004), and thus highly significant, when amalgamating within-trial and across-trial information. However, when separating within-trial from across-trial information, the interaction is -0.007 (95% CI: -0.019 to 0.005; p = 0.22), and thus its magnitude and statistical significance are greatly reduced. We recommend that meta-analysts should only use within-trial information to examine individual predictors of treatment effect and that one-stage IPD models should separate within-trial from across-trial information to avoid ecological bias. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd

  11. Numerical simulation of heat transfer to separation tio2/water nanofluids flow in an asymmetric abrupt expansion

    Directory of Open Access Journals (Sweden)

    Oon Cheen Sean

    2015-01-01

    Full Text Available Flow separation and reattachment of 0.2% TiO2 nanofluid in an asymmetric abrupt expansion is studied in this paper. Such flows occur in various engineering and heat transfer applications. Computational fluid dynamics package (FLUENT is used to investigate turbulent nanofluid flow in the horizontal double-tube heat exchanger. The meshing of this model consists of 43383 nodes and 74891 elements. Only a quarter of the annular pipe is developed and simulated as it has symmetrical geometry. Standard k-epsilon second order implicit, pressure based-solver equation is applied. Reynolds numbers between 17050 and 44545, step height ratio of 1 and 1.82 and constant heat flux of 49050 W/m2 was utilized in the simulation. Water was used as a working fluid to benchmark the study of the heat transfer enhancement in this case. Numerical simulation results show that the increase in the Reynolds number increases the heat transfer coefficient and Nusselt number of the flowing fluid. Moreover, the surface temperature will drop to its lowest value after the expansion and then gradually increase along the pipe. Finally, the chaotic movement and higher thermal conductivity of the TiO2 nanoparticles have contributed to the overall heat transfer enhancement of the nanofluid compare to the water.

  12. SimTB, a simulation toolbox for fMRI data under a model of spatiotemporal separability.

    Science.gov (United States)

    Erhardt, Erik B; Allen, Elena A; Wei, Yonghua; Eichele, Tom; Calhoun, Vince D

    2012-02-15

    We introduce SimTB, a MATLAB toolbox designed to simulate functional magnetic resonance imaging (fMRI) datasets under a model of spatiotemporal separability. The toolbox meets the increasing need of the fMRI community to more comprehensively understand the effects of complex processing strategies by providing a ground truth that estimation methods may be compared against. SimTB captures the fundamental structure of real data, but data generation is fully parameterized and fully controlled by the user, allowing for accurate and precise comparisons. The toolbox offers a wealth of options regarding the number and configuration of spatial sources, implementation of experimental paradigms, inclusion of tissue-specific properties, addition of noise and head movement, and much more. A straightforward data generation method and short computation time (3-10 seconds for each dataset) allow a practitioner to simulate and analyze many datasets to potentially understand a problem from many angles. Beginning MATLAB users can use the SimTB graphical user interface (GUI) to design and execute simulations while experienced users can write batch scripts to automate and customize this process. The toolbox is freely available at http://mialab.mrn.org/software together with sample scripts and tutorials. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Simulated Frosts At Different Phenological Stages of the Potato Crop and Their Impact On Yields Cv Ccompis: Preliminary Studies

    International Nuclear Information System (INIS)

    Fairlie, T. E.; Ortega, A

    1994-01-01

    The frost damages on the potato crop were simulated through an experiment in the Jiscuani community, in Southern Peru, Puno. Five levels of foliar damage (0, 25, 50, 75 and 100%) in different phenological stages were evaluated for their impact on tuber yield. The most significant phenological damages resulted at plant germination and at the early stolon formation, when foliar damage was higher than 50%. Moreover, the greatest effect on yield was caused at flowering stage (100 days after planting), recording reductions from 15 to 55 % at the different damage levels. The methodology for the frost simulation, cutting foliar sections according damage levels and making further rubbing on foliar area was apparently adequate. (author) [es

  14. Three-dimensional simulation of nonstationary flow phenomena in last stage. Exhaust hood compartment and its elements

    Energy Technology Data Exchange (ETDEWEB)

    Solodov, V.G. [Kharkov State Automobile and Highway Technical University, Theoretical Mechanics and Hydraulics Department, Kharkov (Ukraine)

    1997-12-31

    The article describes numerical models and some results of numerical simulation of self-excited oscillatory flow regimes through exhaust diffusers of large steam turbines, operating as a part of compartment (jointly with last stage). The modelling is based on a model of ideal gas flow and full nonstationary 3D formulation and 2nd time and space order explicit Godunov`s scheme. (author) 11 refs.

  15. Nuclear Cryogenic Propulsion Stage (NCPS) Fuel Element Testing in the Nuclear Thermal Rocket Element Environmental Simulator (NTREES)

    Science.gov (United States)

    Emrich, William J., Jr.

    2017-01-01

    To support the on-going nuclear thermal propulsion effort, a state-of-the-art non nuclear experimental test setup has been constructed to evaluate the performance characteristics of candidate fuel element materials and geometries in representative environments. The facility to perform this testing is referred to as the Nuclear Thermal Rocket Element Environment Simulator (NTREES). Last year NTREES was successfully used to satisfy a testing milestone for the Nuclear Cryogenic Propulsion Stage (NCPS) project and met or exceeded all required objectives.

  16. Enantiomeric separation and simulation studies of pheniramine, oxybutynin, cetirizine, and brinzolamide chiral drugs on amylose-based columns.

    Science.gov (United States)

    Ali, Imran; Al-Othman, Zeid A; Al-Warthan, Abdulrahman; Alam, Syed Dilshad; Farooqi, Javed A

    2014-03-01

    Solid phase extraction (SPE)-chiral separation of the important drugs pheniramine, oxybutynin, cetirizine, and brinzolamide was achieved on the C18 cartridge and AmyCoat (150 x 46 mm) and Chiralpak AD (25 cm x 0.46 cm id) chiral columns in human plasma. Pheniramine, oxybutynin, cetirizine, and brinzolamide were resolved using n-hexane-2-PrOH-DEA (85:15:0.1, v/v), n-hexane-2-PrOH-DEA (80:20:0.1, v/v), n-hexane-2-PrOH-DEA (70:30:0.2, v/v), and n-hexane-2-propanol (90:10, v/v) as mobile phases. The separation was carried out at 25 ± 1 ºC temperature with detection at 225 nm for cetirizine and oxybutynin and 220 nm for pheniramine and brinzolamide. The flow rates of the mobile phases were 0.5 mL min(-1). The retention factors of pheniramine, oxybutynin, cetirizine and brinzolamide were 3.25 and 4.34, 4.76 and 5.64, 6.10 and 6.60, and 1.64 and 2.01, respectively. The separation factors of these drugs were 1.33, 1.18, 1.09 and 1.20 while their resolutions factors were 1.09, 1.45, 1.63 and 1.25, and 1.15, respectively. The absolute configurations of the eluted enantiomers of the reported drugs were determined by simulation studies. It was observed that the order of enantiomers elution of the reported drugs was S-pheniramine > R-pheniramine; R-oxybutynin > S-oxybutynin; S-cetirizine > R-cetirizine; and S-brinzolamide > R-brinzolamide. The mechanism of separation was also determined at the supramolecular level by considering interactions and modeling results. The reported SPE-chiral high-performance liquid chromatography (HPLC) methods are suitable for the enantiomeric analyses of these drugs in any biological sample. In addition, simulation studies may be used to determine the absolute configuration of the first and second eluted enantiomers. © 2014 Wiley Periodicals, Inc.

  17. Changes in micro-relief during different water erosive stages of purple soil under simulated rainfall.

    Science.gov (United States)

    Luo, Jian; Zheng, Zicheng; Li, Tingxuan; He, Shuqin

    2018-02-22

    This study investigated the variation characteristics of micro-topography during successive erosive stages of water erosion: splash erosion (SpE), sheet erosion (ShE), and rill erosion (RE). Micro-topography was quantified using surface elevation change, soil roughness (SR) and multifractal model. Results showed that the area of soil surface elevation decay increased gradually with the development of water erosion. With rainfall, the combined effects of the detachment by raindrop impact and the transport of runoff decreased SR, whereas rill erosion contributed to increase SR. With the increase in slope gradient, soil erosion area gradually decreased at the splash erosion stage. By contrast, soil erosion area initially decreased and then increased at the sheet and rill erosion stages. The width of the D q spectra (ΔD) values increased at the splash erosion stage and then decreased at the sheet and rill erosion stages on the 10° slope, opposite to that on the 15° slope. The ΔD values decreased with the evolution of water erosive stages on the 20° slope. The slope had an enhancing effect on the evolution of water erosion. In this study, we clarified the essence of micro-topography and laid a theoretical foundation for further understanding diverse hydrological processes.

  18. Simulation, design and proof-of-concept of a two-stage continuous hydrothermal flow synthesis reactor for synthesis of functionalized nano-sized inorganic composite materials

    DEFF Research Database (Denmark)

    Zielke, Philipp; Xu, Yu; Simonsen, Søren Bredmose

    2016-01-01

    Computational fluid dynamics simulations were employed to evaluate several mixer geometries for a novel two-stage continuous hydrothermal flow synthesis reactor. The addition of a second stage holds the promise of allowing the synthesis of functionalized nano-materials as for example core......-shell or decorated particles. Based on the simulation results, a reactor system employing a confined jet mixer in the first and a counter-flow mixer in the second stage was designed and built. The two-stage functionality and synthesis capacity is shown on the example of single- and two-stage syntheses of pure...

  19. Computational Flow Dynamic Simulation of Micro Flow Field Characteristics Drainage Device Used in the Process of Oil-Water Separation

    Directory of Open Access Journals (Sweden)

    Guangya Jin

    2017-01-01

    Full Text Available Aqueous crude oil often contains large amounts of produced water and heavy sediment, which seriously threats the safety of crude oil storage and transportation. Therefore, the proper design of crude oil tank drainage device is prerequisite for efficient purification of aqueous crude oil. In this work, the composition and physicochemical properties of crude oil samples were tested under the actual conditions encountered. Based on these data, an appropriate crude oil tank drainage device was developed using the principle of floating ball and multiphase flow. In addition, the flow field characteristics in the device were simulated and the contours and streamtraces of velocity magnitude at different nine moments were obtained. Meanwhile, the improvement of flow field characteristics after the addition of grids in crude oil tank drainage device was validated. These findings provide insights into the development of effective selection methods and serve as important references for oil-water separation process.

  20. Effect of bond-disorder on the phase-separation kinetics of binary mixtures: A Monte Carlo simulation study

    Science.gov (United States)

    Singh, Awaneesh; Singh, Amrita; Chakraborti, Anirban

    2017-09-01

    We present Monte Carlo (MC) simulation studies of phase separation in binary (AB) mixtures with bond-disorder that is introduced in two different ways: (i) at randomly selected lattice sites and (ii) at regularly selected sites. The Ising model with spin exchange (Kawasaki) dynamics represents the segregation kinetics in conserved binary mixtures. We find that the dynamical scaling changes significantly by varying the number of disordered sites in the case where bond-disorder is introduced at the randomly selected sites. On the other hand, when we introduce the bond-disorder in a regular fashion, the system follows the dynamical scaling for the modest number of disordered sites. For a higher number of disordered sites, the evolution morphology illustrates a lamellar pattern formation. Our MC results are consistent with the Lifshitz-Slyozov power-law growth in all the cases.

  1. A simulation-based interval two-stage stochastic model for agricultural nonpoint source pollution control through land retirement

    International Nuclear Information System (INIS)

    Luo, B.; Li, J.B.; Huang, G.H.; Li, H.L.

    2006-01-01

    This study presents a simulation-based interval two-stage stochastic programming (SITSP) model for agricultural nonpoint source (NPS) pollution control through land retirement under uncertain conditions. The modeling framework was established by the development of an interval two-stage stochastic program, with its random parameters being provided by the statistical analysis of the simulation outcomes of a distributed water quality approach. The developed model can deal with the tradeoff between agricultural revenue and 'off-site' water quality concern under random effluent discharge for a land retirement scheme through minimizing the expected value of long-term total economic and environmental cost. In addition, the uncertainties presented as interval numbers in the agriculture-water system can be effectively quantified with the interval programming. By subdividing the whole agricultural watershed into different zones, the most pollution-related sensitive cropland can be identified and an optimal land retirement scheme can be obtained through the modeling approach. The developed method was applied to the Swift Current Creek watershed in Canada for soil erosion control through land retirement. The Hydrological Simulation Program-FORTRAN (HSPF) was used to simulate the sediment information for this case study. Obtained results indicate that the total economic and environmental cost of the entire agriculture-water system can be limited within an interval value for the optimal land retirement schemes. Meanwhile, a best and worst land retirement scheme was obtained for the study watershed under various uncertainties

  2. Separation of rare earths by means of acid organophosphorous compounds. Structure-activity study by molecular simulation

    International Nuclear Information System (INIS)

    Fourcot, Fabrice

    1991-01-01

    The increasing number of industrial applications of rare earths has resulted in an increased demand in purified rare earths whereas their separation is difficult due to their high chemical similarity. The search for a better separation leads to the search for more selective extraction agents. Organophosphorous compounds appear to be the most selective. As the search for new extraction agents resulting in high lanthanide extraction efficiency or in a better selectivity between rare earths has been mainly empiric, this research thesis aims at developing a molecular simulation method which allows the number of molecules to be synthesized and tested to be reduced. After having briefly recalled general knowledge on liquid-liquid extraction and on rare earths, and described calculation methods (quantum methods, methods based on molecular mechanics, conformational analysis, methods of charge calculation), the author proposes a critical review of literature related to rare earth liquid-liquid extraction by organophosphorous acids with respect to the used extraction agent. The molecular modelling issue is then addressed by describing ways to apply it to extraction problems, faced problems, brought solutions and obtained results

  3. A multi-stage method for connecting participatory sensing and noise simulations.

    Science.gov (United States)

    Hu, Mingyuan; Che, Weitao; Zhang, Qiuju; Luo, Qingli; Lin, Hui

    2015-01-22

    Most simulation-based noise maps are important for official noise assessment but lack local noise characteristics. The main reasons for this lack of information are that official noise simulations only provide information about expected noise levels, which is limited by the use of large-scale monitoring of noise sources, and are updated infrequently. With the emergence of smart cities and ubiquitous sensing, the possible improvements enabled by sensing technologies provide the possibility to resolve this problem. This study proposed an integrated methodology to propel participatory sensing from its current random and distributed sampling origins to professional noise simulation. The aims of this study were to effectively organize the participatory noise data, to dynamically refine the granularity of the noise features on road segments (e.g., different portions of a road segment), and then to provide a reasonable spatio-temporal data foundation to support noise simulations, which can be of help to researchers in understanding how participatory sensing can play a role in smart cities. This study first discusses the potential limitations of the current participatory sensing and simulation-based official noise maps. Next, we explain how participatory noise data can contribute to a simulation-based noise map by providing (1) spatial matching of the participatory noise data to the virtual partitions at a more microscopic level of road networks; (2) multi-temporal scale noise estimations at the spatial level of virtual partitions; and (3) dynamic aggregation of virtual partitions by comparing the noise values at the relevant temporal scale to form a dynamic segmentation of each road segment to support multiple spatio-temporal noise simulations. In this case study, we demonstrate how this method could play a significant role in a simulation-based noise map. Together, these results demonstrate the potential benefits of participatory noise data as dynamic input sources for

  4. A Multi-Stage Method for Connecting Participatory Sensing and Noise Simulations

    Directory of Open Access Journals (Sweden)

    Mingyuan Hu

    2015-01-01

    Full Text Available Most simulation-based noise maps are important for official noise assessment but lack local noise characteristics. The main reasons for this lack of information are that official noise simulations only provide information about expected noise levels, which is limited by the use of large-scale monitoring of noise sources, and are updated infrequently. With the emergence of smart cities and ubiquitous sensing, the possible improvements enabled by sensing technologies provide the possibility to resolve this problem. This study proposed an integrated methodology to propel participatory sensing from its current random and distributed sampling origins to professional noise simulation. The aims of this study were to effectively organize the participatory noise data, to dynamically refine the granularity of the noise features on road segments (e.g., different portions of a road segment, and then to provide a reasonable spatio-temporal data foundation to support noise simulations, which can be of help to researchers in understanding how participatory sensing can play a role in smart cities. This study first discusses the potential limitations of the current participatory sensing and simulation-based official noise maps. Next, we explain how participatory noise data can contribute to a simulation-based noise map by providing (1 spatial matching of the participatory noise data to the virtual partitions at a more microscopic level of road networks; (2 multi-temporal scale noise estimations at the spatial level of virtual partitions; and (3 dynamic aggregation of virtual partitions by comparing the noise values at the relevant temporal scale to form a dynamic segmentation of each road segment to support multiple spatio-temporal noise simulations. In this case study, we demonstrate how this method could play a significant role in a simulation-based noise map. Together, these results demonstrate the potential benefits of participatory noise data as dynamic

  5. Simulations on Nickel target preparation and separation of Ni(II)-Cu(II) matrix for production of radioisotope 64Cu

    International Nuclear Information System (INIS)

    Sunarhadijoso Soenarjo; Wira Y Rahman; Sriyono; Triyanto

    2011-01-01

    The simulations on Nickel target preparation and separation of Ni(II)-Cu(II) matrix has been carried out as a preliminary study for production of medical radioisotope Cu-64 based on nuclear reaction of 64 Ni (p,n) 64 Cu. The nickel target preparation was performed by means of electroplating method using acidic solution of nickel chloride - boric acid mixture and basic solution of nickel sulphate - nickel chloride mixture on a silver - surfaced-target holder. The simulated solution of Ni(II) - Cu(II) matrix was considered as the solution of post-proton-irradiated nickel target containing both irradiated nickel and radioactive copper, but in the presented work the proton irradiation of nickel target was omitted, while the radioactive copper was originally obtained from neutron irradiation of CuO target. The separation of radioactive copper from the nickel target matrix was based on anion exchange column chromatography in which the radiocopper was conditioned to form anion complex CuCl 4 2- and retained on the column while the nickel was kept in the form of Ni 2+ cation and eluted off from the column. The retained radioactive copper was then eluted out the column in the condition of dilute HCl changing back the copper anion complex into Cu 2+ cation. It was found that the electroplating result from the acidic solution was more satisfied than that from the basic solution. By conditioning the matrix solution at HCl 6 M, the radioactive copper was found in the forms of Cu 2+ and CuCl 4 2- while the nickel was totally in the form of Ni 2+ . In the condition of HCl 9 M, the radioactive copper was mostly in the form of CuCl 4 2- while the nickel was found as both Ni 2+ and NiCl 4 2- . The best condition of separation was in HCl 8 M in which the radioactive copper was mostly in the form of CuCl 4 2- while the nickel was mostly in the form of Ni 2+ . The retained CuCl 4 2- was then changed back into Cu 2+ cation form and eluted out the column by using HCl 0.05 M. The

  6. Numerical simulation of brain tumor growth model using two-stage ...

    African Journals Online (AJOL)

    In the recent years, the study of glioma growth to be an active field of research Mathematical models that describe the proliferation and diffusion properties of the growth have been developed by many researchers. In this work, the performance analysis of two-stage Gauss-Seidel (TSGS) method to solve the glioma growth ...

  7. An Evolutionary Algorithm and discrete event simulation for optimizing inspection strategies for multi-stage processes

    NARCIS (Netherlands)

    Van Volsem, Sofie; Dullaert, Wout; Van Landeghem, Hendrik

    2007-01-01

    The problem of determining the optimal inspection strategy for a given multi-stage production process, i.e. the inspection strategy that results in the lowest total inspection cost, while still assuring a required output quality, is modelled as a joint optimization of inspection location, type and

  8. Numerical simulation of 3-D turbulent flow through entire stage in a multistage centrifugal pump

    International Nuclear Information System (INIS)

    Huang, S.; Islam, M.F.; Liu, P.

    2005-01-01

    A three-dimensional turbulent flow through a multistage centrifugal pump is numerically simulated using a commercial CFD software package. The simulation and analysis include flow fields in rotating impeller and stationary diffuser and is completed in a multiple reference frame. The standard k-ε turbulence model is applied. The analysis of the simulation reveals that the reverse flows exist in the zone near the impeller exit and diffuser entrance, resulting in flow field asymmetric and unsteady. There is a considerable interference on velocity field at impeller exit due to the interaction between impeller blades and diffuser vanes. The hydraulic performance is connected and evaluated with the 3-D computational flow field. The current computation is verified by comparing predicted and measured head. (author)

  9. Optimization of separate hydrogen and methane production from cassava wastewater using two-stage upflow anaerobic sludge blanket reactor (UASB) system under thermophilic operation.

    Science.gov (United States)

    Intanoo, Patcharee; Rangsanvigit, Pramoch; Malakul, Pomthong; Chavadej, Sumaeth

    2014-12-01

    The objective of this study was to investigate the separate hydrogen and methane productions from cassava wastewater by using a two-stage upflow anaerobic sludge blanket (UASB) system under thermophilic operation. Recycle ratio of the effluent from methane bioreactor-to-feed flow rate was fixed at 1:1 and pH of hydrogen UASB unit was maintained at 5.5. At optimum COD loading rate of 90 kg/m3 d based on the feed COD load and hydrogen UASB volume, the produced gas from the hydrogen UASB unit mainly contained H2 and CO2 which provided the maximum hydrogen yield (54.22 ml H2/g COD applied) and specific hydrogen production rate (197.17 ml/g MLVSSd). At the same optimum COD loading rate, the produced gas from the methane UASB unit mainly contained CH4 and CO2 without H2 which were also consistent with the maximum methane yield (164.87 ml CH4/g COD applied) and specific methane production rate (356.31 ml CH4/g MLVSSd). The recycling operation minimized the use of NaOH for pH control in hydrogen UASB unit. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Experimental verification of Equilibrium-Stage and Rate-Based Simulations

    NARCIS (Netherlands)

    Abu-Zahra, M.R.M.; Jansens, P.J.; Knudsen, J.N.; Goetheer, E.L.V.

    2012-01-01

    In this article, pilot plant data for CO2 post-combustion capture are discussed and compared with modelling results. The objectives of this paper are to evaluate the overall performance of the CO2 capture pilot plant using both experimental and simulation results. In addition, this work is aiming to

  11. A detached eddy simulation model for the study of lateral separation zones along a large canyon-bound river

    Science.gov (United States)

    Alvarez, Laura V.; Schmeeckle, Mark W.; Grams, Paul E.

    2017-01-01

    Lateral flow separation occurs in rivers where banks exhibit strong curvature. In canyon-boundrivers, lateral recirculation zones are the principal storage of fine-sediment deposits. A parallelized,three-dimensional, turbulence-resolving model was developed to study the flow structures along lateralseparation zones located in two pools along the Colorado River in Marble Canyon. The model employs thedetached eddy simulation (DES) technique, which resolves turbulence structures larger than the grid spacingin the interior of the flow. The DES-3D model is validated using Acoustic Doppler Current Profiler flowmeasurements taken during the 2008 controlled flood release from Glen Canyon Dam. A point-to-pointvalidation using a number of skill metrics, often employed in hydrological research, is proposed here forfluvial modeling. The validation results show predictive capabilities of the DES model. The model reproducesthe pattern and magnitude of the velocity in the lateral recirculation zone, including the size and position ofthe primary and secondary eddy cells, and return current. The lateral recirculation zone is open, havingcontinuous import of fluid upstream of the point of reattachment and export by the recirculation returncurrent downstream of the point of separation. Differences in magnitude and direction of near-bed andnear-surface velocity vectors are found, resulting in an inward vertical spiral. Interaction between therecirculation return current and the main flow is dynamic, with large temporal changes in flow direction andmagnitude. Turbulence structures with a predominately vertical axis of vorticity are observed in the shearlayer becoming three-dimensional without preferred orientation downstream.

  12. Simulating chiral magnetic effect and anomalous transport phenomena in the pre-equilibrium stages of heavy-ion collisions

    Science.gov (United States)

    Mace, Mark; Mueller, Niklas; Schlichting, Sören; Sharma, Sayantan

    2017-11-01

    We present a first principles approach to study the Chiral Magnetic Effect during the pre-equilibrium stage of a heavy-ion collision. We discuss the dynamics of the Chiral Magnetic Effect and Chiral Magnetic Wave based on real-time lattice simulations with dynamical (Wilson and Overlap) fermions simultaneously coupled to color and electromagnetic fields. While for light quarks we observe a dissipation-less transport of charges as in anomalous hydrodynamics, we demonstrate that for heavier quarks the effects of explicit chiral symmetry breaking lead to a significant reduction of the associated currents.

  13. CFD simulation of transient stage of continuous countercurrent hydrolysis of canola oil

    KAUST Repository

    Wang, Weicheng

    2012-08-01

    Computational Fluid Dynamic (CFD) modeling of a continuous countercurrent hydrolysis process was performed using ANSYS-CFX. The liquid properties and flow behavior such as density, specific heats, dynamic viscosity, thermal conductivity, and thermal expansivity as well as water solubility of the hydrolysis components triglyceride, diglyceride, monoglyceride, free fatty acid, and glycerol were calculated. Chemical kinetics for the hydrolysis reactions were simulated in this model by applying Arrhenius parameters. The simulation was based on actual experimental reaction conditions including temperature and water-to-oil ratio. The results not only have good agreement with experimental data but also show instantaneous distributions of concentrations of every component in hydrolysis reaction. This model provided visible insight into the continuous countercurrent hydrolysis process. © 2012 Elsevier Ltd.

  14. The analysis of the flow with water injection in a centrifugal compressor stage using CFD simulation

    Science.gov (United States)

    Michal, Tomášek; Richard, Matas; Tomáš, Syka

    2017-09-01

    This text deals with the principle of direct cooling of the pressure gas in a centrifugal compressor based on evaporation of the additional fluid phase in a control domain. A decrease of the gas temperature is reached by taking the heat, which is required for evaporation of the fluid phase. The influence of additional fluid phase on the parameters of the multiphase flow is compared with the ideal gas simulation in the defined domain and with the same boundary conditions.

  15. [Effects of simulated acid rain on oilseed rape (Brassica napus) physiological characteristics at flowering stage and yield].

    Science.gov (United States)

    Cao, Chun-Xin; Zhou, Qin; Han, Liang-Liang; Zhang, Pei; Jiang, Hai-Dong

    2010-08-01

    A pot experiment was conducted to study the effects of different acidity simulated acid rain on the physiological characteristics at flowering stage and yield of oilseed rape (B. napus cv. Qinyou 9). Comparing with the control (pH 6.0), weak acidity (pH = 4.0-5.0) simulated acid rain stimulated the rape growth to some extent, but had less effects on the plant biomass, leaf chlorophyll content, photosynthetic characteristics, and yield. With the further increase of acid rain acidity, the plant biomass, leaf chlorophyll content, photosynthetic rate, antioxidative enzyme activities, and non-enzyme antioxidant contents all decreased gradually, while the leaf malonyldialdehyde (MDA) content and relative conductivity increased significantly. As the results, the pod number per plant, seed number per pod, seed weight, and actual yield decreased. However, different yield components showed different sensitivity to simulated acid rain. With the increasing acidity of simulated acid rain, the pod number per plant and the seed number per pod decreased significantly, while the seed weight was less affected.

  16. Circuit models and three-dimensional electromagnetic simulations of a 1-MA linear transformer driver stage

    Directory of Open Access Journals (Sweden)

    D. V. Rose

    2010-09-01

    Full Text Available A 3D fully electromagnetic (EM model of the principal pulsed-power components of a high-current linear transformer driver (LTD has been developed. LTD systems are a relatively new modular and compact pulsed-power technology based on high-energy density capacitors and low-inductance switches located within a linear-induction cavity. We model 1-MA, 100-kV, 100-ns rise-time LTD cavities [A. A. Kim et al., Phys. Rev. ST Accel. Beams 12, 050402 (2009PRABFM1098-440210.1103/PhysRevSTAB.12.050402] which can be used to drive z-pinch and material dynamics experiments. The model simulates the generation and propagation of electromagnetic power from individual capacitors and triggered gas switches to a radially symmetric output line. Multiple cavities, combined to provide voltage addition, drive a water-filled coaxial transmission line. A 3D fully EM model of a single 1-MA 100-kV LTD cavity driving a simple resistive load is presented and compared to electrical measurements. A new model of the current loss through the ferromagnetic cores is developed for use both in circuit representations of an LTD cavity and in the 3D EM simulations. Good agreement between the measured core current, a simple circuit model, and the 3D simulation model is obtained. A 3D EM model of an idealized ten-cavity LTD accelerator is also developed. The model results demonstrate efficient voltage addition when driving a matched impedance load, in good agreement with an idealized circuit model.

  17. FE-simulation of the initial stages of rafting in nickel-base superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Bioermann, H.; Feng Hua; Mughrabi, H. [Erlangen-Nuernberg Univ., Erlangen (Germany). Lehrstuhl fuer Werkstoffwissenschaften 1

    2000-07-01

    In the present work, the model of Socrate and Parks which takes into account the plastic deformation and which applies the method of finite elements (FE) using an energy-perturbation approach will be extended by the introduction of a further contribution to the driving force for rafting, cf. This additional driving force is based on the local variation of the hydrostatic stresses arising from the anisotropic distribution of dislocations after deformation, in combination with the different lattice parameters of the two phases {gamma} and {gamma}'. It is an alternative formulation of the driving force introduced recently. With the present model, the initial stages of rafting and the build-up of internal stresses and strains are determined. (orig.)

  18. An experimental study of adolescent sleep restriction during a simulated school week: changes in phase, sleep staging, performance and sleepiness.

    Science.gov (United States)

    Agostini, Alex; Carskadon, Mary A; Dorrian, Jillian; Coussens, Scott; Short, Michelle A

    2017-04-01

    This laboratory study investigated the impact of restricted sleep during a simulated school week on circadian phase, sleep stages and daytime functioning. Changes were examined across and within days and during a simulated weekend recovery. Participants were 12 healthy secondary school students (six male) aged 15-17 years [mean = 16.1 years, standard deviation (SD) = 0.9]. After 2 nights with 10 h (21:30-07:30 hours), time in bed was restricted to 5 h for 5 nights (02:30-07:30 hours), then returned to 10 h time in bed for 2 nights (21:30-07:30 hours). Saliva was collected in dim light on the first and last sleep restriction nights to measure melatonin onset phase. Sleep was recorded polysomnographically, and the Psychomotor Vigilance Task (PVT) and Karolinska Sleepiness Scale were undertaken 3-hourly while awake. Average phase delay measured by melatonin was 3 h (SD = 50 min). Compared to baseline, sleep during the restriction period contained a smaller percentage of Stages 1 and 2 and rapid eye movement (REM) and a greater percentage of Stage 4. PVT lapses increased significantly during sleep restriction and did not return to baseline levels during recovery. Subjective sleepiness showed a similar pattern during restriction, but returned to baseline levels during recovery. Results suggest that sustained attention in adolescents is affected negatively by sleep restriction, particularly in the early morning, and that a weekend of recovery sleep is insufficient to restore performance. The discrepancy between sleepiness ratings and performance may indicate a lack of perception of this residual impairment. © 2016 European Sleep Research Society.

  19. Simulation of elution profiles in liquid chromatography - II: Investigation of injection volume overload under gradient elution conditions applied to second dimension separations in two-dimensional liquid chromatography.

    Science.gov (United States)

    Stoll, Dwight R; Sajulga, Ray W; Voigt, Bryan N; Larson, Eli J; Jeong, Lena N; Rutan, Sarah C

    2017-11-10

    An important research direction in the continued development of two-dimensional liquid chromatography (2D-LC) is to improve the detection sensitivity of the method. This is especially important in applications where injection of large volumes of effluent from the first dimension ( 1 D) column into the second dimension ( 2 D) column leads to severe 2 D peak broadening and peak shape distortion. For example, this is common when coupling two reversed-phase columns and the organic solvent content of the 1 D mobile phase overwhelms the 2 D column with each injection of 1 D effluent, leading to low resolution in the second dimension. In a previous study we validated a simulation approach based on the Craig distribution model and adapted from the work of Czok and Guiochon [1] that enabled accurate simulation of simple isocratic and gradient separations with very small injection volumes, and isocratic separations with mismatched injection and mobile phase solvents [2]. In the present study we have extended this simulation approach to simulate separations relevant to 2D-LC. Specifically, we have focused on simulating 2 D separations where gradient elution conditions are used, there is mismatch between the sample solvent and the starting point in the gradient elution program, injection volumes approach or even exceed the dead volume of the 2 D column, and the extent of sample loop filling is varied. To validate this simulation we have compared results from simulations and experiments for 101 different conditions, including variation in injection volume (0.4-80μL), loop filling level (25-100%), and degree of mismatch between sample organic solvent and the starting point in the gradient elution program (-20 to +20% ACN). We find that that the simulation is accurate enough (median errors in retention time and peak width of -1.0 and -4.9%, without corrections for extra-column dispersion) to be useful in guiding optimization of 2D-LC separations. However, this requires that real

  20. The KS-KT-100 plant for two-stage vitrification of radioactive waste: results of tests with simulators

    International Nuclear Information System (INIS)

    Davydov, V.I.; Dobrygin, P.G.; Dolgov, V.V.; Sergeev, G.A.

    1976-01-01

    The Soviet Union has developed a two-stage process for phosphate vitrification of liquid radioactive waste involving the use, at the initial stage, of calcination in the pseudo-liquefied layer, followed by melting of the calcinate in a ceramic crucible (second stage). On the basis of the laboratory studies and bench tests using experimental equipment, the authors have developed and tried out an enlarged plant - the KS-KT-100. The plant includes units for preparing the solution, evaporation, calcination, melting and gas purification. The initial solution containing 240 g/litre of aluminium nitrate, 125 g/litre of sodium nitrate, 120 to 130 g/litre of orthophosphoric acid, and 90 to 150 g/litre of industrial molasses simulated fluxed nitrate waste. The tests have shown that the various units operate satisfactorily. The authors have determined the technological parameters for evaporation, calcination of the solution and melting of the calcinate. The presence of molasses in the solution (150 g/litre) makes it possible to decompose and distil 40% of the nitrate ion during evaporation. The calcination temperature is 350 to 400 0 C, and the fluidization rate 1.5 m/s. The capacity of the plant for the initial solution is 100 litres/h, for the evaporated solution 65 litres/h, and for the glass 20 kg/h. The efficiency of the gas purification system ranges between 10 7 and 10 9 . The test results show the feasibility of the two-stage method of vitrification in actual practice. (author)

  1. Single-stage quintuplet for upgrading triplet based lens system: Simulation for Atomki microprobe

    Science.gov (United States)

    Ponomarov, Artem; Rajta, Istvan; Nagy, Gyula; Romanenko, Oleksandr V.

    2017-08-01

    Among different configurations of lens systems for nuclear microprobes, the most common one is a triplet of magnetic quadrupole lenses. Nowadays, microanalysis and material modification will undoubtedly benefit from an improvement in spatial resolution. This work presents the results of simulations for improvement of the Oxford Triplet lens system at the Atomki microprobe with consideration of its system parameters and measured beam brightness distribution. For this purpose, an additional single-unit doublet of lenses with two power supplies was introduced. Using earlier developed methods, such a quintuplet system was optimized in order to determine the parameters which provided the highest resolution for different current operational modes with the same microprobe geometry. The tolerances for lens positioning accuracy were also calculated. The obtained quintuplet parameters indicate a resolution improvement for the Atomki microprobe compared to the Oxford Triplet system and these results validate further experimental testing of the proposed quintuplet.

  2. Simulation and parameter analysis of a two-stage desiccant cooing/heating system driven by solar air collectors

    International Nuclear Information System (INIS)

    Li, H.; Dai, Y.J.; Köhler, M.; Wang, R.Z.

    2013-01-01

    Highlights: ► A solar desiccant cooling/heating system is simulation studied. ► The mean deviation is about 10.5% for temperature and 9.6% for humidity ratio. ► The 51.7% of humidity load and 76% of the total cooling can be handled. ► About 49.0% of heating load can be handled by solar energy. ► An optimization of solar air collector has been investigated. - Abstract: To increase the fraction of solar energy might be used in supplying energy for the operation of a building, a solar desiccant cooling and heating system was modeled in Simulink. First, base case performance models were programmed according to the configuration of the installed solar desiccant system and verified by the experimental data. Then, the year-round performance about the system was simulated. Last, design parameters of solar air collectors were optimized that include collector area, air leakage and thermal insulation. Comparison between numerical and experimental results shows good agreement. During the simulation, the humidity load for 63 days (51.7%) can be totally handled by the two-stage desiccant cooling unit. For seasonal total heating load, about 49.0% can be handled by solar energy. Based on optimized results, the thermal energy subsystem functioned to its expected performance in solar energy collection and thermal storage

  3. NUMERICAL SIMULATION OF UJONG SEUDEUN LAND SEPARATION CAUSED BY THE 2004 INDIAN OCEAN TSUNAMI, ACEH-INDONESIA

    Directory of Open Access Journals (Sweden)

    Musa Al'ala

    2015-07-01

    Full Text Available The Aceh province in Indonesia, located around the Sumatra subduction area, was one of the worst hit areas with respect to damage from the impact of the 2004 Indian Ocean tsunami. A 9.15 Mw earthquake triggered the tsunami. One of the impacts was the disconnection of several areas from their mainland, thus creating new small islands. This happened around Ujong Seudeun village in Aceh Jaya District. Prior to the tsunami, the village had approximately 500 residents. However, after the tsunami, the area was severely eroded and a small strait had been inserted between the village and the Sumatra Island mainland. This study investigates the magnitude of the tsunami wave forces that separated the area to yield a newly deserted small island. This study was conducted by numerical simulations and by coupling the COMCOT (Cornell Multi-grid Coupled Tsunami Model and Delft3D models. These tools have specific advantages, namely, COMCOT’s linear modeling is based on a series of earthquake mechanisms and Delft3D uses non-linear morphological dynamic modeling. Their software includes the explicit leapfrog finite difference scheme (COMCOT and the non-linear shallow water equation (Delft3D. Bathymetry data fromnewly formed coastline and the small island’s shape were digitized using 2005 Quickbird Images. Results from this research reveal the estimated tsunami wave heights and forces that disconnected the small island of Ujong Seuden from the Sumatra Island mainland. These results can be used to further develop the COMCOT model to incorporate sediment modules.

  4. How did Marine Isotope Stage 3 and Last Glacial Maximum climates differ? – Perspectives from equilibrium simulations

    Directory of Open Access Journals (Sweden)

    C. J. Van Meerbeeck

    2009-03-01

    Full Text Available Dansgaard-Oeschger events occurred frequently during Marine Isotope Stage 3 (MIS3, as opposed to the following MIS2 period, which included the Last Glacial Maximum (LGM. Transient climate model simulations suggest that these abrupt warming events in Greenland and the North Atlantic region are associated with a resumption of the Thermohaline Circulation (THC from a weak state during stadials to a relatively strong state during interstadials. However, those models were run with LGM, rather than MIS3 boundary conditions. To quantify the influence of different boundary conditions on the climates of MIS3 and LGM, we perform two equilibrium climate simulations with the three-dimensional earth system model LOVECLIM, one for stadial, the other for interstadial conditions. We compare them to the LGM state simulated with the same model. Both climate states are globally 2°C warmer than LGM. A striking feature of our MIS3 simulations is the enhanced Northern Hemisphere seasonality, July surface air temperatures being 4°C warmer than in LGM. Also, despite some modification in the location of North Atlantic deep water formation, deep water export to the South Atlantic remains unaffected. To study specifically the effect of orbital forcing, we perform two additional sensitivity experiments spun up from our stadial simulation. The insolation difference between MIS3 and LGM causes half of the 30–60° N July temperature anomaly (+6°C. In a third simulation additional freshwater forcing halts the Atlantic THC, yielding a much colder North Atlantic region (−7°C. Comparing our simulation with proxy data, we find that the MIS3 climate with collapsed THC mimics stadials over the North Atlantic better than both control experiments, which might crudely estimate interstadial climate. These results suggest that freshwater forcing is necessary to return climate from warm interstadials to cold stadials during MIS3. This changes our perspective, making the stadial

  5. Determination of thermodynamic values of acidic dissociation constants and complexation constants of profens and their utilization for optimization of separation conditions by Simul 5 Complex.

    Science.gov (United States)

    Riesová, Martina; Svobodová, Jana; Ušelová, Kateřina; Tošner, Zdeněk; Zusková, Iva; Gaš, Bohuslav

    2014-10-17

    In this paper we determine acid dissociation constants, limiting ionic mobilities, complexation constants with β-cyclodextrin or heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, and mobilities of resulting complexes of profens, using capillary zone electrophoresis and affinity capillary electrophoresis. Complexation parameters are determined for both neutral and fully charged forms of profens and further corrected for actual ionic strength and variable viscosity in order to obtain thermodynamic values of complexation constants. The accuracy of obtained complexation parameters is verified by multidimensional nonlinear regression of affinity capillary electrophoretic data, which provides the acid dissociation and complexation parameters within one set of measurements, and by NMR technique. A good agreement among all discussed methods was obtained. Determined complexation parameters were used as input parameters for simulations of electrophoretic separation of profens by Simul 5 Complex. An excellent agreement of experimental and simulated results was achieved in terms of positions, shapes, and amplitudes of analyte peaks, confirming the applicability of Simul 5 Complex to complex systems, and accuracy of obtained physical-chemical constants. Simultaneously, we were able to demonstrate the influence of electromigration dispersion on the separation efficiency, which is not possible using the common theoretical approaches, and predict the electromigration order reversals of profen peaks. We have shown that determined acid dissociation and complexation parameters in combination with tool Simul 5 Complex software can be used for optimization of separation conditions in capillary electrophoresis. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. LARGE-EDDY SIMULATIONS OF A SEPARATION/REATTACHMENT BUBBLE IN A TURBULENT-BOUNDARY-LAYER SUBJECTED TO A PRESCRIBED UPPER-BOUNDARY, VERTICAL-VELOCITY PROFILE

    KAUST Repository

    Cheng, Wan

    2015-06-30

    We describe large-eddy simulations of turbulent boundary-layer flow over a flat plate at high Reynolds number in the presence of an unsteady, three-dimensional flow separation/reattachment bubble. The stretched-vortex subgrid-scale model is used in the main flow domain combined with a wall-model that is a two-dimensional extension of that developed by Chung & Pullin (2009). Flow separation and re-attachment of the incoming boundary layer is induced by prescribing wall-normal velocity distribution on the upper boundary of the flow domain that produces an adverse-favorable stream-wise pressure distribution at the wall. The LES predicts the distribution of mean shear stress along the wall including the interior of the separation bubble. Several properties of the separation/reattachment flow are discussed.

  7. Dynamic solar-powered multi-stage direct contact membrane distillation system: Concept design, modeling and simulation

    KAUST Repository

    Lee, Jung Gil

    2017-04-26

    This paper presents a theoretical analysis of the monthly average daily and hourly performances of a solar-powered multi-stage direct contact membrane distillation (SMDCMD) system with an energy recovery scheme and dynamic operating system. Mid-latitude meteorological data from Busan, Korea is employed, featuring large climate variation over the course of one year. The number of module stages used by the dynamic operating scheme changes dynamically based on the inlet feed temperature of the successive modules, which results in an improvement of the water production and thermal efficiency. The simulations of the SMDCMD system are carried out to investigate the spatial and temporal variations in the feed and permeate temperatures and permeate flux. The monthly average daily water production increases from 0.37m3/day to 0.4m3/day and thermal efficiency increases from 31% to 45% when comparing systems both without and with dynamic operation in December. The water production with respect to collector area ranged from 350m2 to 550m2 and the seawater storage tank volume ranged from 16m3 to 28.8m3, and the solar fraction at various desired feed temperatures from 50°C to 80°C have been investigated in October and December.

  8. A Monte Carlo simulation based two-stage adaptive resonance theory mapping approach for offshore oil spill vulnerability index classification.

    Science.gov (United States)

    Li, Pu; Chen, Bing; Li, Zelin; Zheng, Xiao; Wu, Hongjing; Jing, Liang; Lee, Kenneth

    2014-09-15

    In this paper, a Monte Carlo simulation based two-stage adaptive resonance theory mapping (MC-TSAM) model was developed to classify a given site into distinguished zones representing different levels of offshore Oil Spill Vulnerability Index (OSVI). It consisted of an adaptive resonance theory (ART) module, an ART Mapping module, and a centroid determination module. Monte Carlo simulation was integrated with the TSAM approach to address uncertainties that widely exist in site conditions. The applicability of the proposed model was validated by classifying a large coastal area, which was surrounded by potential oil spill sources, based on 12 features. Statistical analysis of the results indicated that the classification process was affected by multiple features instead of one single feature. The classification results also provided the least or desired number of zones which can sufficiently represent the levels of offshore OSVI in an area under uncertainty and complexity, saving time and budget in spill monitoring and response. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. The Kepler Dichotomy in Planetary Disks: Linking Kepler Observables to Simulations of Late-stage Planet Formation

    Science.gov (United States)

    Moriarty, John; Ballard, Sarah

    2016-11-01

    NASA’s Kepler Mission uncovered a wealth of planetary systems, many with planets on short-period orbits. These short-period systems reside around 50% of Sun-like stars and are similarly prevalent around M dwarfs. Their formation and subsequent evolution is the subject of active debate. In this paper, we simulate late-stage, in situ planet formation across a grid of planetesimal disks with varying surface density profiles and total mass. We compare simulation results with observable characteristics of the Kepler sample. We identify mixture models with different primordial planetesimal disk properties that self-consistently recover the multiplicity, radius, period and period ratio, and duration ratio distributions of the Kepler planets. We draw three main conclusions. (1) We favor a “frozen-in” narrative for systems of short-period planets, in which they are stable over long timescales, as opposed to metastable. (2) The “Kepler dichotomy,” an observed phenomenon of the Kepler sample wherein the architectures of planetary systems appear to either vary significantly or have multiple modes, can naturally be explained by formation within planetesimal disks with varying surface density profiles. Finally, (3) we quantify the nature of the “Kepler dichotomy” for both GK stars and M dwarfs, and find that it varies with stellar type. While the mode of planet formation that accounts for high multiplicity systems occurs in 24% ± 7% of planetary systems orbiting GK stars, it occurs in 63% ± 16% of planetary systems orbiting M dwarfs.

  10. A Reliable Turning Process by the Early Use of a Deep Simulation Model at Several Manufacturing Stages

    Directory of Open Access Journals (Sweden)

    Gorka Urbikain

    2017-05-01

    Full Text Available The future of machine tools will be dominated by highly flexible and interconnected systems, in order to achieve the required productivity, accuracy, and reliability. Nowadays, distortion and vibration problems are easily solved in labs for the most common machining operations by using models based on the equations describing the physical laws of the machining processes; however, additional efforts are needed to overcome the gap between scientific research and real manufacturing problems. In fact, there is an increasing interest in developing simulation packages based on “deep-knowledge and models” that aid machine designers, production engineers, or machinists to get the most out of the machine-tools. This article proposes a methodology to reduce problems in machining by means of a simulation utility, which uses the main variables of the system and process as input data, and generates results that help in the proper decision-making and machining plan. Direct benefits can be found in (a the fixture/clamping optimal design; (b the machine tool configuration; (c the definition of chatter-free optimum cutting conditions and (d the right programming of cutting toolpaths at the Computer Aided Manufacturing (CAM stage. The information and knowledge-based approach showed successful results in several local manufacturing companies and are explained in the paper.

  11. Steered molecular dynamics simulations of a type IV pilus probe initial stages of a force-induced conformational transition.

    Directory of Open Access Journals (Sweden)

    Joseph L Baker

    2013-04-01

    Full Text Available Type IV pili are long, protein filaments built from a repeating subunit that protrudes from the surface of a wide variety of infectious bacteria. They are implicated in a vast array of functions, ranging from bacterial motility to microcolony formation to infection. One of the most well-studied type IV filaments is the gonococcal type IV pilus (GC-T4P from Neisseria gonorrhoeae, the causative agent of gonorrhea. Cryo-electron microscopy has been used to construct a model of this filament, offering insights into the structure of type IV pili. In addition, experiments have demonstrated that GC-T4P can withstand very large tension forces, and transition to a force-induced conformation. However, the details of force-generation, and the atomic-level characteristics of the force-induced conformation, are unknown. Here, steered molecular dynamics (SMD simulation was used to exert a force in silico on an 18 subunit segment of GC-T4P to address questions regarding the nature of the interactions that lead to the extraordinary strength of bacterial pili. SMD simulations revealed that the buried pilin α1 domains maintain hydrophobic contacts with one another within the core of the filament, leading to GC-T4P's structural stability. At the filament surface, gaps between pilin globular head domains in both the native and pulled states provide water accessible routes between the external environment and the interior of the filament, allowing water to access the pilin α1 domains as reported for VC-T4P in deuterium exchange experiments. Results were also compared to the experimentally observed force-induced conformation. In particular, an exposed amino acid sequence in the experimentally stretched filament was also found to become exposed during the SMD simulations, suggesting that initial stages of the force induced transition are well captured. Furthermore, a second sequence was shown to be initially hidden in the native filament and became exposed upon

  12. Steered molecular dynamics simulations of a type IV pilus probe initial stages of a force-induced conformational transition.

    Science.gov (United States)

    Baker, Joseph L; Biais, Nicolas; Tama, Florence

    2013-04-01

    Type IV pili are long, protein filaments built from a repeating subunit that protrudes from the surface of a wide variety of infectious bacteria. They are implicated in a vast array of functions, ranging from bacterial motility to microcolony formation to infection. One of the most well-studied type IV filaments is the gonococcal type IV pilus (GC-T4P) from Neisseria gonorrhoeae, the causative agent of gonorrhea. Cryo-electron microscopy has been used to construct a model of this filament, offering insights into the structure of type IV pili. In addition, experiments have demonstrated that GC-T4P can withstand very large tension forces, and transition to a force-induced conformation. However, the details of force-generation, and the atomic-level characteristics of the force-induced conformation, are unknown. Here, steered molecular dynamics (SMD) simulation was used to exert a force in silico on an 18 subunit segment of GC-T4P to address questions regarding the nature of the interactions that lead to the extraordinary strength of bacterial pili. SMD simulations revealed that the buried pilin α1 domains maintain hydrophobic contacts with one another within the core of the filament, leading to GC-T4P's structural stability. At the filament surface, gaps between pilin globular head domains in both the native and pulled states provide water accessible routes between the external environment and the interior of the filament, allowing water to access the pilin α1 domains as reported for VC-T4P in deuterium exchange experiments. Results were also compared to the experimentally observed force-induced conformation. In particular, an exposed amino acid sequence in the experimentally stretched filament was also found to become exposed during the SMD simulations, suggesting that initial stages of the force induced transition are well captured. Furthermore, a second sequence was shown to be initially hidden in the native filament and became exposed upon stretching.

  13. Modeling and Simulation of the ARES UPPER STAGE Transportation, Lifting, Stacking and Mating Operations Within the Vehicle Assembly Building at KSC

    Science.gov (United States)

    Kromis, Phillip A.

    2010-01-01

    This viewgraph presentation describes the modeling and simulation of the Ares Upper Stage Transportation, lifting, stacking, and mating operations within the Vehicle Assembly Building (VAB) at Kennedy Space Center (KSC). An aerial view of KSC Launch Shuttle Complex, two views of the Delmia process control layout, and an upper stage move subroutine and breakdown are shown. An overhead image of the VAB and the turning basin along with the Pegasus barge at the turning basin are also shown. This viewgraph presentation also shows the actual design and the removal of the mid-section spring tensioners, the removal of the AFT rear and forward tensioners tie downs, and removing the AFT hold down post and mount. US leaving the Pegasus Barge, the upper stage arriving at transfer aisle, upper stage receiving/inspection in transfer aisle, and an overhead view of upper stage receiving/inspection in transfer aisle are depicted. Five views of the actual connection of the cabling to the upper stage aft lifting hardware are shown. The upper stage transporter forward connector, two views of the rotation horizontal to vertical, the disconnection of the rear bolt ring cabling, the lowering of the upper stage to the inspection stand, disconnection of the rear bolt ring from the upper stage, the lifting of the upper stage and inspection of AFT fange, and the transfer of upper stage in an integrated stack are shown. Six views of the mating of the upper stage to the first stage are depicted. The preparation, inspection, and removal of the forward dome are shown. The upper stage mated on the integrated stack and crawler is also shown. This presentation concludes with A Rapid Upper Limb Assessment (RULA) utilizing male and female models for assessing risk factors to the upper extremities of human beings in an actual physical environment.

  14. Numerical Simulation of Hydrothermal Salt Separation Process and Analysis and Cost Estimating of Shipboard Liquid Waste Disposal

    National Research Council Canada - National Science Library

    Hunt, Andrew R

    2007-01-01

    .... In 2006, the cost for waste water disposal Navy-wide was 54 million dollars, There are many advanced waste water treatment technologies in the research and development stage at academic institutions...

  15. Supramolecular separation mechanism of pentafluorophenyl column using ibuprofen and omeprazole as markers: LC-MS and simulation study.

    Science.gov (United States)

    Hussain, Afzal; AlAjmi, Mohamed F; Ali, Imran

    2018-02-12

    The pentafluorophenyl (PFP) column is emerging as a new advancement in separation science to analyze a wide range of analytes and, thus, its separation mechanism at supramolecular level is significant. We developed a mechanism for the separation of ibuprofen and omeprazole using different combinations (ranging from 50:50 to 60:40) of water-acetonitrile containing 0.1% formic acid as the mobile phase. The column used was Waters Acquity UPLC HSS PFP (75 × 2.1 mm, 1.8 μm). The reverse order of elution was observed in different combinations of the mobile phases. The docking study indicated hydrogen bonding between ibuprofen and PFP stationary phase (binding energy was -11.30 kJ/mol). Separation at PFP stationary phase is controlled by hydrogen bonding along with π-π interactions. This stationary phase may be used to analyze both aromatic and aliphatic analytes. The developed mechanism will be useful to separate various analytes by considering the possible interactions, leading to saving of energy, time and money. In addition, this work will be highly useful in preparative chromatography where separation is the major problem at a large scale. Moreover, the developed LC-MS-QTOF method may be used to analyze ibuprofen and omeprazole in an unknown sample owing to the low value of detection limits. Copyright © 2018 John Wiley & Sons, Ltd.

  16. Development of a system based in a digital signal processor (DSP) for a simulator of power regulation in a reactor: first stage

    International Nuclear Information System (INIS)

    Benitez R, J.S.; Perez C, B.

    2002-01-01

    The first stage of the development of a digital system based on a DSP is presented which forms part of an hybrid simulator for the power regulation in am model of the punctual kinetics of a TRIGA reactor type. The DSP performs the regulation, using a Mandami type algorithm of diffuse control. In the algorithm, the universe of the output variable is discretized for performing in an unique stage the aggregation functions and dis-diffusization. (Author)

  17. Modifier-free separation of trivalent actinides and lanthanides from fast reactor simulated high-level liquid waste using N,N-di-octyl-2-hydroxyacetamide

    International Nuclear Information System (INIS)

    Prathibha, T.; Antony, M.P.; Homi Bhabha National Institute, Mumbai; Kumaresan, R.; Nayak, P.K.; Venkatesan, K.A.; Subramanian, G.G.S.; Rajeswari, S.; Kalaiyarasu, T.; Karunakaran, R.

    2017-01-01

    The extraction behaviour of Am(III) and other metal ions present in the fast reactor simulated high- level liquid waste (FR-SHLLW) was studied using a modifier-free solvent phase composed of N,N-di-octyl-2-hydroxyacetamide (DOHyA) in n-dodecane. Quantitative extraction of Am(III) was achieved with the co-extraction of all lanthanides, Y(III) and Mo(VI) in the first five stages of a 20-stage mixer-settler. During the stripping run with 0.5 M HNO 3 , Am(III), Ln(III) and Y(III) were quantitatively transferred to the aqueous product in three stages. The other extracted metal ions were retained in organic phase. The results showed that the extraction performance of DOHyA was superior to other amide extractant systems reported in the literature. (author)

  18. Analysis of the ITQ-12 zeolite performance in propane-propylene separations using a combination of experiments and molecular simulations

    NARCIS (Netherlands)

    Gutiérrez-Sevillano, J.J.; Dubbeldam, D.; Rey, F.; Valencia, S.; Palomino, M.; Martín-Calvo, A.; Calero, S.

    2010-01-01

    We present a combined computational and experimental approach to evaluate the suitability of the ITQ-12 nanoporous material (ITW) as a propane−propylene separation device. For this, we have computed adsorption and diffusion of propane and propylene in the ITQ-12 zeolite. The propane isotherm is

  19. Application of FTLOADDS to Simulate Flow, Salinity, and Surface-Water Stage in the Southern Everglades, Florida

    Science.gov (United States)

    Wang, John D.; Swain, Eric D.; Wolfert, Melinda A.; Langevin, Christian D.; James, Dawn E.; Telis, Pamela A.

    2007-01-01

    representation of coastal flows. This improvement most likely is due to a more stable numerical representation of the coastal creek outlets. Sensitivity analyses were performed by varying frictional resistance, leakage, barriers to flow, and topography. Changing frictional resistance values in inland areas was shown to improve water-level representation locally, but to have a negligible effect on area-wide values. These changes have only local effects and are not physically based (as are the unchanged values), and thus have limited validity. Sensitivity tests indicate that the overall accuracy of the simulation is diminished if leakage between surface water and ground water is not simulated. The inclusion of a major road as a complete barrier to surface-water flow influenced the local distribution and timing of flow; however, the changes in total flow and individual creekflows were negligible. The model land-surface altitude was lowered by 0.1 meter to determine the sensitivity to topographic variation. This topographic sensitivity test produced mixed results in matching field data. Overall, the representation of stage did not improve definitively. A final calibration utilized the results of the sensitivity analysis to refine the TIME application. To accomplish this calibration, the friction coefficient was reduced at the northern boundary inflow and increased in the southwestern corner of the model, the evapotranspiration function was varied, additional data were used for the ground-water head boundary along the southeast, and the frictional resistance of the primary coastal creek outlet was increased. The calibration improved the match between measured and simulated total flows to Florida Bay and coastal salinities. Agreement also was improved at most of the water-level sites throughout the model domain.

  20. Monte Carlo Simulations Probing the Adsorptive Separation of Hydrogen Sulfide/Methane Mixtures Using All-Silica Zeolites.

    Science.gov (United States)

    Shah, Mansi S; Tsapatsis, Michael; Siepmann, J Ilja

    2015-11-10

    Selective removal of hydrogen sulfide (H2S) from sour natural gas mixtures is one of the key challenges facing the natural gas industry. Adsorption and pervaporation processes utilizing nanoporous materials, such as zeolites, can be alternatives to highly energy-intensive amine-based absorption processes. In this work, the adsorption behavior of binary mixtures containing H2S and methane (CH4) in seven different all-silica zeolite frameworks (CHA, DDR, FER, IFR, MFI, MOR, and MWW) is investigated using Gibbs ensemble Monte Carlo simulations at two temperatures (298 and 343 K) and pressures ranging from 1 to 50 bar. The simulations demonstrate high selectivities that, with the exception of MOR, increase with increasing H2S concentration due to favorable sorbate-sorbate interactions. The simulations indicate significant inaccuracies of predictions using unary adsorption data and ideal adsorbed solution theory. In addition, the adsorption of binary H2S/H2O mixtures in MFI is considered to probe whether the presence of H2S induces coadsorption and reduces the hydrophobic character of all-silica zeolites. The simulations show preferential adsorption of H2S from moist gases with a selectivity of about 18 over H2O.

  1. Adjusting for treatment switching in randomised controlled trials - A simulation study and a simplified two-stage method.

    Science.gov (United States)

    Latimer, Nicholas R; Abrams, K R; Lambert, P C; Crowther, M J; Wailoo, A J; Morden, J P; Akehurst, R L; Campbell, M J

    2017-04-01

    Estimates of the overall survival benefit of new cancer treatments are often confounded by treatment switching in randomised controlled trials (RCTs) - whereby patients randomised to the control group are permitted to switch onto the experimental treatment upon disease progression. In health technology assessment, estimates of the unconfounded overall survival benefit associated with the new treatment are needed. Several switching adjustment methods have been advocated in the literature, some of which have been used in health technology assessment. However, it is unclear which methods are likely to produce least bias in realistic RCT-based scenarios. We simulated RCTs in which switching, associated with patient prognosis, was permitted. Treatment effect size and time dependency, switching proportions and disease severity were varied across scenarios. We assessed the performance of alternative adjustment methods based upon bias, coverage and mean squared error, related to the estimation of true restricted mean survival in the absence of switching in the control group. We found that when the treatment effect was not time-dependent, rank preserving structural failure time models (RPSFTM) and iterative parameter estimation methods produced low levels of bias. However, in the presence of a time-dependent treatment effect, these methods produced higher levels of bias, similar to those produced by an inverse probability of censoring weights method. The inverse probability of censoring weights and structural nested models produced high levels of bias when switching proportions exceeded 85%. A simplified two-stage Weibull method produced low bias across all scenarios and provided the treatment switching mechanism is suitable, represents an appropriate adjustment method.

  2. Coal liquefaction process streams characterization and evaluation: Application of liquid chromatographic separation methods to THF-soluble portions of integrated two-stage coal liquefaction resids

    Energy Technology Data Exchange (ETDEWEB)

    Green, J.B.; Pearson, C.D.; Young, L.L.; Green, J.A. [National Inst. for Petroleum and Energy Research, Bartlesville, OK (United States)

    1992-05-01

    This study demonstrated the feasibility of using non-aqueous ion exchange liquid chromatography (NIELC) for the examination of the tetrahydrofuran (THF)-soluble distillation resids and THF-soluble whole oils derived from direct coal liquefaction. The technique can be used to separate the material into a number of acid, base, and neutral fractions. Each of the fractions obtained by NIELC was analyzed and then further fractionated by high-performance liquid chromatography (HPLC). The separation and analysis schemes are given in the accompanying report. With this approach, differences can be distinguished among samples obtained from different process streams in the liquefaction plant and among samples obtained at the same sampling location, but produced from different feed coals. HPLC was directly applied to one THF-soluble whole process oil without the NIELC preparation, with limited success. The direct HPLC technique used was directed toward the elution of the acid species into defined classes. The non-retained neutral and basic components of the oil were not analyzable by the direct HPLC method because of solubility limitations. Sample solubility is a major concern in the application of these techniques.

  3. Three-dimensional numerical simulation of a continuously rotating detonation in the annular combustion chamber with a wide gap and separate delivery of fuel and oxidizer

    Science.gov (United States)

    Frolov, S. M.; Dubrovskii, A. V.; Ivanov, V. S.

    2016-07-01

    The possibility of integrating the Continuous Detonation Chamber (CDC) in a gas turbine engine (GTE) is demonstrated by means of three-dimensional (3D) numerical simulations, i. e., the feasibility of the operation process in the annular combustion chamber with a wide gap and with separate feeding of fuel (hydrogen) and oxidizer (air) is proved computationally. The CDC with an upstream isolator damping pressure disturbances propagating towards the compressor is shown to exhibit a gain in the total pressure of 15% as compared with the same combustion chamber operating in the deflagration mode.

  4. Electrode Materials, Thermal Annealing Sequences, and Lateral/Vertical Phase Separation of Polymer Solar Cells from Multiscale Molecular Simulations

    KAUST Repository

    Lee, Cheng-Kuang

    2014-12-10

    © 2014 American Chemical Society. The nanomorphologies of the bulk heterojunction (BHJ) layer of polymer solar cells are extremely sensitive to the electrode materials and thermal annealing conditions. In this work, the correlations of electrode materials, thermal annealing sequences, and resultant BHJ nanomorphological details of P3HT:PCBM BHJ polymer solar cell are studied by a series of large-scale, coarse-grained (CG) molecular simulations of system comprised of PEDOT:PSS/P3HT:PCBM/Al layers. Simulations are performed for various configurations of electrode materials as well as processing temperature. The complex CG molecular data are characterized using a novel extension of our graph-based framework to quantify morphology and establish a link between morphology and processing conditions. Our analysis indicates that vertical phase segregation of P3HT:PCBM blend strongly depends on the electrode material and thermal annealing schedule. A thin P3HT-rich film is formed on the top, regardless of bottom electrode material, when the BHJ layer is exposed to the free surface during thermal annealing. In addition, preferential segregation of P3HT chains and PCBM molecules toward PEDOT:PSS and Al electrodes, respectively, is observed. Detailed morphology analysis indicated that, surprisingly, vertical phase segregation does not affect the connectivity of donor/acceptor domains with respective electrodes. However, the formation of P3HT/PCBM depletion zones next to the P3HT/PCBM-rich zones can be a potential bottleneck for electron/hole transport due to increase in transport pathway length. Analysis in terms of fraction of intra- and interchain charge transports revealed that processing schedule affects the average vertical orientation of polymer chains, which may be crucial for enhanced charge transport, nongeminate recombination, and charge collection. The present study establishes a more detailed link between processing and morphology by combining multiscale molecular

  5. Effect of the flow profile on separation efficiency in pressure-assisted reversed-polarity capillary zone electrophoresis of anions: Simulation and experimental evaluation.

    Science.gov (United States)

    Jarvas, Gabor; Szigeti, Marton; Guttman, Andras

    2018-02-19

    Capillary electrophoresis connected to electrospray ionization mass spectrometry is a promising combination to analyze complex biological samples. The use of sheathless electrospray ionization interfaces, such as a porous nanoelectrospray capillary emitter, requires the application of forward flow (either by pressure or electroosmosis) to maintain the electrospray process. The analysis of solute molecules with strong negative charges (e.g., aminopyrenetrisulfonate labeled glycans) necessitates a reversed-polarity capillary electrophoresis separation mode, in which case the electroosmotic flow is counter current, thus pressure assistance is necessary. In this study, we compared the effect of forced convection with and without counter electroosmotic flow on the resulting separation efficiency in capillary electrophoresis based on flow profile simulations by computational fluid dynamics technique and by actual experiments. The efficiencies of the detected peaks were calculated from the resulting electropherograms and found approximately 790 000 plates/m for electrophoresis with counter electroosmotic flow, 16 000 plates/m with pressure only (such as would be in open tubular liquid chromatography) and 400 000 plates/m for electrophoresis with simultaneous counter electroosmotic flow and forward pressure assistance, which validates the simulation data. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. A direct numerical simulation investigation of the synthetic jet frequency effects on separation control of low-Re flow past an airfoil

    KAUST Repository

    Zhang, Wei

    2015-05-05

    We present results of direct numerical simulations of a synthetic jet (SJ) based separation control of flow past a NACA-0018 (National Advisory Committee for Aeronautics) airfoil, at 10° angle of attack and Reynolds number 104 based on the airfoil chord length C and uniform inflow velocity U 0. The actuator of the SJ is modeled as a spanwise slot on the airfoil leeward surface and is placed just upstream of the leading edge separation position of the uncontrolled flow. The momentum coefficient of the SJ is chosen at a small value 2.13 × 10−4 normalized by that of the inflow. Three forcing frequencies are chosen for the present investigation: the low frequency (LF) F + = feC/U 0 = 0.5, the medium frequency (MF) F + = 1.0, and the high frequency (HF) F + = 4.0. We quantify the effects of forcing frequency for each case on the separation control and related vortex dynamics patterns. The simulations are performed using an energy conservative fourth-order parallel code. Numerical results reveal that the geometric variation introduced by the actuator has negligible effects on the mean flow field and the leading edge separation pattern; thus, the separation control effects are attributed to the SJ. The aerodynamic performances of the airfoil, characterized by lift and lift-to-drag ratio, are improved for all controlled cases, with the F + = 1.0 case being the optimal one. The flow in the shear layer close to the actuator is locked to the jet, while in the wake this lock-in is maintained for the MF case but suppressed by the increasing turbulent fluctuations in the LF and HF cases. The vortex evolution downstream of the actuator presents two modes depending on the frequency: the vortex fragmentation and merging mode in the LF case where the vortex formed due to the SJ breaks up into several vortices and the latter merge as convecting downstream; the discrete vortices mode in the HF case where discrete vortices form and convect downstream without any fragmentation and

  7. Two stages of immiscible liquid separation in the formation of Panzhihua-type Fe-Ti-V oxide deposits, SW China

    Directory of Open Access Journals (Sweden)

    Mei-Fu Zhou

    2013-09-01

    Full Text Available Magmatic oxide deposits in the ∼260 Ma Emeishan Large Igneous Province (ELIP, SW China and northern Vietnam, are important sources of Fe, Ti and V. Some giant magmatic Fe-Ti-V oxide deposits, such as the Panzhihua, Hongge, and Baima deposits, are well described in the literature and are hosted in layered mafic-ultramafic intrusions in the Panxi region, the central ELIP. The same type of ELIP-related deposits also occur far to the south and include the Anyi deposit, about 130 km south of Panzhihua, and the Mianhuadi deposit in the Red River fault zone. The Anyi deposit is relatively small but is similarly hosted in a layered mafic intrusion. The Mianhuadi deposit has a zircon U-Pb age of ∼260 Ma and is thus contemporaneous with the ELIP. This deposit was variably metamorphosed during the Indosinian orogeny and Red River faulting. Compositionally, magnetite of the Mianhuadi deposit contains smaller amounts of Ti and V than that of the other deposits, possibly attributable to the later metamorphism. The distribution of the oxide ore deposits is not related to the domal structure of the ELIP. One major feature of all the oxide deposits in the ELIP is the spatial association of oxide-bearing gabbroic intrusions, syenitic plutons and high-Ti flood basalts. Thus, we propose that magmas from a mantle plume were emplaced into a shallow magma chamber where they were evolved into a field of liquid immiscibility to form two silicate liquids, one with an extremely Fe-Ti-rich gabbroic composition and the other syenitic. An immiscible Fe-Ti-(P oxide melt may then separate from the mafic magmas to form oxide deposits. The parental magmas from which these deposits formed were likely Fe-Ti-rich picritic in composition and were derived from enriched asthenospheric mantle at a greater depth than the magmas that produced sulfide-bearing intrusions of the ELIP.

  8. Model based simulation of alternative transmission concepts in early stages of product development process; Einsatz von Simulationsmodellen zur Beurteilung von alternativen Getriebekonzepten in fruehen Phasen des Produktentstehungsprozesses

    Energy Technology Data Exchange (ETDEWEB)

    Albers, A.; Ott, S.; Seifermann, A. [Karlsruhe Univ. (Germany). IPEK - Inst. fuer Produktentwicklung

    2006-07-01

    The contribution describes a method for assessing the new transmission concepts and investigate their advantages in alternative powertrain systems. Simulation models of different powertrains were used in order to make the different concepts comparable in an early stage of the product developmentprocess. Further, it is shown how the Contact and Channel Model (C and CM) can be used for modelling individual transmission concepts. These models can help to identify and assess interdependences between part systems and components. (orig.)

  9. Separation of fission produced 106Ru from simulated high level nuclear wastes for production of brachytherapy sources

    International Nuclear Information System (INIS)

    Blicharska, Magdalena; Bartoś, Barbara; Krajewski, Seweryn; Bilewicz, Aleksander

    2014-01-01

    Brachytherapy is the common method for treating various tumors, and currently 106 Ru and 125 I applicators are the most frequently used. Considering that 106 Ru is a β emitter with maximum energy of 3.54 MeV, it is best indicated in the treatment of small melanomas, with up to 20 mm tissue range. 106 Ru is commercially obtained from neutron irradiated high enrichment 235 U target in process of production 99 Mo. At present, there are only a handful of ageing reactors worldwide capable of producing the 99 Mo, therefore alternative strategies for production of this key medical isotope are explored. In our work, we propose to use liquid high-level radioactive waste as a source of high activity of 106 Ru. Simple calculations indicate that 1 dm 3 of HLLW solution after 4 years of cooling contains about 500 GBq of 106 Ru. This amount of activity is enough for production of about few thousands of brachytherapy sources. Present communication reports results of our process development studies on the recovery of ruthenium radioisotopes from simulated solution of high level radioactive waste using oxidation-extraction method

  10. Three-Dimensional Unsteady Simulation of a Modern High Pressure Turbine Stage Using Phase Lag Periodicity: Analysis of Flow and Heat Transfer

    Science.gov (United States)

    Shyam, Vikram; Ameri, Ali; Luk, Daniel F.; Chen, Jen-Ping

    2010-01-01

    Unsteady three-dimensional RANS simulations have been performed on a highly loaded transonic turbine stage and results are compared to steady calculations as well as experiment. A low Reynolds number k- turbulence model is employed to provide closure for the RANS system. A phase-lag boundary condition is used in the periodic direction. This allows the unsteady simulation to be performed by using only one blade from each of the two rows. The objective of this paper is to study the effect of unsteadiness on rotor heat transfer and to glean any insight into unsteady flow physics. The role of the stator wake passing on the pressure distribution at the leading edge is also studied. The simulated heat transfer and pressure results agreed favorably with experiment. The time-averaged heat transfer predicted by the unsteady simulation is higher than the heat transfer predicted by the steady simulation everywhere except at the leading edge. The shock structure formed due to stator-rotor interaction was analyzed. Heat transfer and pressure at the hub and casing were also studied. Thermal segregation was observed that leads to the heat transfer patterns predicted by steady and unsteady simulations to be different.

  11. Simulations

    CERN Document Server

    Ngada, Narcisse

    2015-06-15

    The complexity and cost of building and running high-power electrical systems make the use of simulations unavoidable. The simulations available today provide great understanding about how systems really operate. This paper helps the reader to gain an insight into simulation in the field of power converters for particle accelerators. Starting with the definition and basic principles of simulation, two simulation types, as well as their leading tools, are presented: analog and numerical simulations. Some practical applications of each simulation type are also considered. The final conclusion then summarizes the main important items to keep in mind before opting for a simulation tool or before performing a simulation.

  12. The Contribution of the Future SWOT Mission to Improve Simulations of River Stages and Stream-Aquifer Interactions at Regional Scale

    Science.gov (United States)

    Saleh, Firas; Filipo, Nicolas; Biancamaria, Sylvain; Habets, Florence; Rodriguez, Enersto; Mognard, Nelly

    2013-09-01

    The main objective of this study is to provide a realistic simulation of river stage in regional river networks in order to improve the quantification of stream-aquifer exchanges and better assess the associated aquifer responses that are often impacted by the magnitude and the frequency of the river stage fluctuations. This study extends the earlier work to improve the modeling of the Seine basin with a focus on simulating the hydrodynamics behavior of the Bassée alluvial wetland, a 120 km reach of the Seine River valley located south- east of Paris. The Bassée is of major importance for the drinking-water supply of Paris and surroundings, in addition to its particular hydrodynamic behavior due to the presence of a number of gravels. In this context, the understanding of stream-aquifer interactions is required for water quantity and quality preservation. A regional distributed process-based hydro(geo)logical model, Eau-Dyssée, is used. It aims at the integrated modeling of the hydrosystem to manage the various elements involved in the quantitative and qualitative aspects of water resources. Eau-Dyssée simulates pseudo 3D flow in aquifer systems solving the diffusivity equation with a finite difference numerical scheme. River flow is simulated with a Muskingum model. In addition to the in-stream discharge, a river stage estimate is needed to calculate the water exchange at the stream-aquifer interface using a conductance model. In this context, the future SWOT mission and its high-spatial resolution imagery can provide surface water level measurements at the regional scale that will permit to better characterize the Bassée complex hydro(geo)logical system and better assess soil water content. Moreover, the Bassée is considered as a potential target for the framework of the AirSWOT airborne campaign in France, 2013.

  13. SimulRad: a Java interface for a Monte-Carlo simulation code to visualize in 3D the early stages of water radiolysis

    International Nuclear Information System (INIS)

    Plante, Ianik L.; Filali-Mouhim, Abdelali; Jay-Gerin, Jean-Paul

    2005-01-01

    Using a Fortran step-by-step Monte-Carlo simulation code of liquid water radiolysis and the Java programming language, we have developed a Java interface software, called SimulRad. This interface enables a user, in a three-dimensional environment, to either visualize the spatial distribution of all reactive species present in the track of an ionizing particle at a chosen simulation time, or present an animation of the chemical development of the particle track over a chosen time interval (between ∼10 -12 and 10 -6 s). It also allows one to select a particular radiation-induced cluster of species to view, in fine detail, the chemical reactions that occur between these species

  14. Inference of strata separation and gas emission paths in longwall overburden using continuous wavelet transform of well logs and geostatistical simulation

    Science.gov (United States)

    Karacan, C. Özgen; Olea, Ricardo A.

    2014-06-01

    Prediction of potential methane emission pathways from various sources into active mine workings or sealed gobs from longwall overburden is important for controlling methane and for improving mining safety. The aim of this paper is to infer strata separation intervals and thus gas emission pathways from standard well log data. The proposed technique was applied to well logs acquired through the Mary Lee/Blue Creek coal seam of the Upper Pottsville Formation in the Black Warrior Basin, Alabama, using well logs from a series of boreholes aligned along a nearly linear profile. For this purpose, continuous wavelet transform (CWT) of digitized gamma well logs was performed by using Mexican hat and Morlet, as the mother wavelets, to identify potential discontinuities in the signal. Pointwise Hölder exponents (PHE) of gamma logs were also computed using the generalized quadratic variations (GQV) method to identify the location and strength of singularities of well log signals as a complementary analysis. PHEs and wavelet coefficients were analyzed to find the locations of singularities along the logs. Using the well logs in this study, locations of predicted singularities were used as indicators in single normal equation simulation (SNESIM) to generate equi-probable realizations of potential strata separation intervals. Horizontal and vertical variograms of realizations were then analyzed and compared with those of indicator data and training image (TI) data using the Kruskal-Wallis test. A sum of squared differences was employed to select the most probable realization representing the locations of potential strata separations and methane flow paths. Results indicated that singularities located in well log signals reliably correlated with strata transitions or discontinuities within the strata. Geostatistical simulation of these discontinuities provided information about the location and extents of the continuous channels that may form during mining. If there is a gas

  15. Effect of Composition Asymmetry on the Phase Separation and Crystallization in Double Crystalline Binary Polymer Blends: A Dynamic Monte Carlo Simulation Study.

    Science.gov (United States)

    Dasmahapatra, Ashok Kumar

    2017-06-15

    Polymer blends offer an exciting material for various potential applications due to their tunable properties by varying constituting components and their relative composition. Our simulation results unravel an intrinsic relationship between crystallization behavior and composition asymmetry. We report simulation results for nonisothermal and isothermal crystallization with weak and strong segregation strength to elucidate the composition dependent crystallization behavior. With increasing composition of low melting B-polymer, macrophase separation temperature changes nonmonotonically, which is attributed to the nonmonotonic change in diffusivity of both polymers. In weak segregation strength, however, at high enough composition of B-polymer, A-polymer yields relatively thicker crystals, which is attributed to the dilution effect exhibited by B-polymer. When B-polymer composition is high enough, it acts like a "solvent" while A-polymer crystallizes. Under this situation, A-polymer segments become more mobile and less facile to crystallize. As a result, A-polymer crystallizes at a relatively low temperature with the formation of thicker crystals. At strong segregation strength, the dilution effect is accompanied by the strong A-B repulsive interaction, which is reflected in a nonmonotonic trend of the mean square radius of gyration with the increasing composition of the B-polymer. Isothermal crystallization also reveals a strong nonmonotonic relationship between composition and crystallization behavior. Two-step, compared to one-step, isothermal crystallization yields better crystals for both polymers.

  16. Operations analysis (study 2.1). Program SEPSIM (solar electric propulsion stage simulation). [in FORTRAN: space tug

    Science.gov (United States)

    Lang, T. J.

    1974-01-01

    Program SEPSIM is a FORTRAN program which performs deployment, servicing, and retrieval missions to synchronous equatorial orbit using a space tug with a continuous low thrust upper stage known as a solar electric propulsion stage (SEPS). The SEPS ferries payloads back and forth between an intermediate orbit and synchronous orbit, and performs the necessary servicing maneuvers in synchronous orbit. The tug carries payloads between the orbiter and the intermediate orbit, deploys fully fueled SEPS vehicles, and retrieves exhausted SEPS vehicles when, and if, required. The program is presently contained in subroutine form in the Logistical On-orbit VEhicle Servicing (LOVES) Program, but can also be run independently with the addition of a simple driver program.

  17. Fractional Models Simulating Non-Fickian Behavior in Four-Stage Single-Well Push-Pull Tests

    Science.gov (United States)

    Chen, Kewei; Zhan, Hongbin; Yang, Qiang

    2017-11-01

    Four-stage single-well push-pull (SWPP) tracer tests, including injection, chasing, resting, and pumping, were conducted in a fractured aquifer at Newark basin. An anomalous transport phenomenon observed in the SWPP tests is the linear decline of breakthrough curves (BTCs) at late time with slope of -1.8 in log-log plots. A time-dependent fractional model is developed to interpret the anomalous transport behavior. This model considers a time-dependent power law memory function and a time-dependent fractional advection-dispersion operator. The fractional advection-dispersion equations (fADE) are solved in a radial coordinate system using the implicit Euler method. A semi-analytical solution of the first-order rate-limited mobile-immobile model (FORMIM) is derived for comparison. It is found that both the nonlocal transport in time and space can produce the long-tailed BTC. A smaller time-fractional or space-fractional index leads to a lower peak concentration and a larger late-time slope. The mass distribution of the fractional-in-space (FS) model exhibits power law decline at the leading plume edge. Early breakthrough during pumping is not observed because the mobile mass at the start of pumping is nonzero and more concentrated near the wellbore. The capacity ratio is an important factor that affects the peak concentration. A larger capacity ratio leads to greater peak concentration. A smaller time-fractional index in the injection, chasing, or resting stage will move the BTC downward and the slope of the late time BTC is determined by the space-fractional index over all stages and the time-fractional index in the pumping stage. The capability of the existing models to recover the BTC of the SWPP test is discussed and some guidelines for how to choose the appropriate model to interpret the SWPP test data are proposed.

  18. Fuel loads and simulated fire behavior in "old-stage" beetle-infested ponderosa pine of the Colorado Plateau

    Science.gov (United States)

    E. Matthew Hansen; Morris C. Johnson; Barbara J. Bentz; James C. Vandygriff; A. Steven. Munson

    2015-01-01

    Recent bark beetle outbreaks in western North America have led to concerns regarding changes in fuel profiles and associated changes in fire behavior. Data are lacking for a range of infestation severities and time since outbreak, especially for relatively arid cover types. We surveyed fuel loads and simulated fire behavior for ponderosa pine stands of the...

  19. Isotope separation

    International Nuclear Information System (INIS)

    Ravoire, Jean

    1978-11-01

    Separation of isotopes is treated in a general way, with special reference to the production of enriched uranium. Uses of separated isotopes are presented quickly. Then basic definitions and theoretical concepts are explained: isotopic effects, non statistical and statistical processes, reversible and irreversible processes, separation factor, enrichment, cascades, isotopic separative work, thermodynamics. Afterwards the main processes and productions are reviewed. Finally the economical and industrial aspects of uranium enrichment are resumed [fr

  20. Glycerol extracting dealcoholization for the biodiesel separation process.

    Science.gov (United States)

    Ye, Jianchu; Sha, Yong; Zhang, Yun; Yuan, Yunlong; Wu, Housheng

    2011-04-01

    By means of utilizing sunflower oil and Jatropha oil as raw oil respectively, the biodiesel transesterification production and the multi-stage extracting separation were carried out experimentally. Results indicate that dealcoholized crude glycerol can be utilized as the extracting agent to achieve effective separation of methanol from the methyl ester phase, and the glycerol content in the dealcoholized methyl esters is as low as 0.02 wt.%. For the biodiesel separation process utilizing glycerol extracting dealcoholization, its technical and equipment information were acquired through the rigorous process simulation in contrast to the traditional biodiesel distillation separation process, and results show that its energy consumption decrease about 35% in contrast to that of the distillation separation process. The glycerol extracting dealcoholization has sufficient feasibility and superiority for the biodiesel separation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Effects of Simulated Microgravity on Otolith Growth of Larval Zebrafish using a Rotating-Wall Vessel: Appropriate Rotation Speed and Fish Developmental Stage

    Science.gov (United States)

    Li, Xiaoyan; Anken, Ralf; Liu, Liyue; Wang, Gaohong; Liu, Yongding

    2017-02-01

    Stimulus dependence is a general feature of developing animal sensory systems. In this respect, it has extensively been shown earlier that fish inner ear otoliths can act as test masses as their growth is strongly affected by altered gravity such as hypergravity obtained using centrifuges, by (real) microgravity achieved during spaceflight or by simulated microgravity using a ground-based facility. Since flight opportunities are scarce, ground-based simulators of microgravity, using a wide variety of physical principles, have been developed to overcome this shortcoming. Not all of them, however, are equally well suited to provide functional weightlessness from the perspective of the biosystem under evaluation. Therefore, the range of applicability of a particular simulator has to be extensively tested. Earlier, we have shown that a Rotating-Wall Vessel (RWV) can be used to provide simulated microgravity for developing Zebrafish regarding the effect of rotation on otolith development. In the present study, we wanted to find the most effective speed of rotation and identify the appropriate developmental stage of Zebrafish, where effects are the largest, in order to provide a methodological basis for future in-depth analyses dedicated to the physiological processes underlying otolith growth at altered gravity. Last not least, we compared data on the effect of simulated microgravity on the size versus the weight of otoliths, since the size usually is measured in related studies due to convenience, but the weight more accurately approximates the physical capacity of an otolith. Maintaining embryos at 10 hours post fertilization for three days in the RWV, we found that 15 revolutions per minute (rpm) yielded the strongest effects on otolith growth. Maintenance of Zebrafish staged at 10 hpf, 1 day post fertilization (dpf), 4 dpf, 7 dpf and 14 dpf for three days at 15 rpm resulted in the most prominent effects in 7 dpf larvae. Weighing versus measuring the size of otoliths

  2. Standing wave design and optimization of a simulated moving bed chromatography for separation of xylobiose and xylose under the constraints on product concentration and pressure drop.

    Science.gov (United States)

    Lee, Chung-Gi; Choi, Jae-Hwan; Park, Chanhun; Wang, Nien-Hwa Linda; Mun, Sungyong

    2017-12-08

    The feasibility of a simulated moving bed (SMB) technology for the continuous separation of high-purity xylobiose (X2) from the output of a β-xylosidase X1→X2 reaction has recently been confirmed. To ensure high economical efficiency of the X2 production method based on the use of xylose (X1) as a starting material, it is essential to accomplish the comprehensive optimization of the X2-separation SMB process in such a way that its X2 productivity can be maximized while maintaining the X2 product concentration from the SMB as high as possible in consideration of a subsequent lyophilization step. To address this issue, a suitable SMB optimization tool for the aforementioned task was prepared based on standing wave design theory. The prepared tool was then used to optimize the SMB operation parameters, column configuration, total column number, adsorbent particle size, and X2 yield while meeting the constraints on X2 purity, X2 product concentration, and pressure drop. The results showed that the use of a larger particle size caused the productivity to be limited by the constraint on X2 product concentration, and a maximum productivity was attained by choosing the particle size such that the effect of the X2-concentration limiting factor could be balanced with that of pressure-drop limiting factor. If the target level of X2 product concentration was elevated, higher productivity could be achieved by decreasing particle size, raising the level of X2 yield, and increasing the column number in the zones containing the front and rear of X2 solute band. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Separation of ethylene glycol and sodium salt of serine by use of a simulated moving-bed adsorber; Giji idoso ni yoru ethylene glycol to serine no Na en no bunri

    Energy Technology Data Exchange (ETDEWEB)

    Seto, T.; Hirata, K.; Odagiri, M.; Imanari, M. [Mitsubishi Chemical Corp., Tokyo (Japan)

    1998-05-10

    Separation of ethylene glycol and sodium salt of serine is important in the processing of serine by the Strecker method using glycol aldehyde produced from ethylene glycol. The separations were successfully carried out using a simulated moving-bed four-zone type adsorber which was composed of a sodium salt of strongly acidic cation exchange resin. The moving-bed adsorber used was slightly different from a conventional one in the manner of setting up Raffinate 2. Separation of this type was simulated by calculations using an analytical solution of steady state rate equation concerning the adsorption and desorption of the ingredients and the moving bed. The condition needed for separation in the four-zone type with Raffinate 2 was discriminated, being generally coincident with the conventional condition of {beta} value. 13 refs., 5 figs., 2 tabs.

  4. Assigning Robust Default Values in Building Performance Simulation Software for Improved Decision-Making in the Initial Stages of Building Design.

    Science.gov (United States)

    Hiyama, Kyosuke

    2015-01-01

    Applying data mining techniques on a database of BIM models could provide valuable insights in key design patterns implicitly present in these BIM models. The architectural designer would then be able to use previous data from existing building projects as default values in building performance simulation software for the early phases of building design. The author has proposed the method to minimize the magnitude of the variation in these default values in subsequent design stages. This approach maintains the accuracy of the simulation results in the initial stages of building design. In this study, a more convincing argument is presented to demonstrate the significance of the new method. The variation in the ideal default values for different building design conditions is assessed first. Next, the influence of each condition on these variations is investigated. The space depth is found to have a large impact on the ideal default value of the window to wall ratio. In addition, the presence or absence of lighting control and natural ventilation has a significant influence on the ideal default value. These effects can be used to identify the types of building conditions that should be considered to determine the ideal default values.

  5. Numerical simulation of the unsteady and turbulent flow in a high-pressure turbine stage; Simulation numerique de l'ecoulement instationnaire et turbulent dans un etage de turbine haute pression

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, G.

    2004-09-15

    The aim of this study concerns the use of numerical methods for the resolution of the Reynolds Averaged Navier Stokes equations adapted to the simulation of the cooling of the trailing edge of a stator in a high pressure turbine. These methods, based on the elsA solver developed at ONERA, use a four steps Runge Kutta time discretization scheme and a Jameson centered space discretization scheme. The scheme is applied through a finite volume approach on control volume centered on the cells of a multi-block structured mesh. Turbulence is simulated either through the algebraic Michel model, or through the one-transport-equation Spalart-Allmaras model, or through the two-transport-equations k 1, k {omega} and k {epsilon} models, and through ASM model. A simulation of the flow in a bidimensional stator, without cooling, is carried out. The cooling, which is realized with trailing edge slots, is then simulated on a bidimensional stator. Because the slot is represented by meshes overlapping the mesh of the smooth blade, the Chimera method is chosen. This method makes it possible computations with overlapping meshes. The comparison with the experimental data, on these two first computations has validated this strategy to represent such slots. The tridimensional simulation of a single stator with taking account of the cooling is then realized. It showed the complex and tridimensional aspects of the main flow with focus on the influence of the cooling system. Finally two steady computations, without and with cooling, and an unsteady computation without cooling are carried out on a high pressure turbine stage. The comparison with the experimental data obtained in the frame of the European Brite-Euram program is made. These results make it possible to determine the effect of the cooling on the flow in a turbine stage. (authors)

  6. Chromatographic hydrogen isotope separation

    International Nuclear Information System (INIS)

    Aldridge, F.T.

    1983-01-01

    Intermetallic compounds with the CaCu5 type of crystal structure, particularly LaNiCo and CaNi5, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen can produce large quantities of heavy water at an effective cost for use in heavy water reactors

  7. Chromatographic hydrogen isotope separation

    Science.gov (United States)

    Aldridge, F.T.

    Intermetallic compounds with the CaCu/sub 5/ type of crystal structure, particularly LaNiCo/sub 4/ and CaNi/sub 5/, exhibit high separation factors and fast equilibrium times and therefore are useful for packing a chromatographic hydrogen isotope separation column. The addition of an inert metal to dilute the hydride improves performance of the column. A large scale multi-stage chromatographic separation process run as a secondary process off a hydrogen feedstream from an industrial plant which uses large volumes of hydrogen cn produce large quantities of heavy water at an effective cost for use in heavy water reactors.

  8. Functionalizing porous aromatic frameworks with polar organic groups for high-capacity and selective CO2 separation: a molecular simulation study.

    Science.gov (United States)

    Babarao, Ravichandar; Dai, Sheng; Jiang, De-en

    2011-04-05

    Porous aromatic frameworks (PAFs) were recently synthesized with the highest surface area to date; one such PAF (PAF-1) has diamond-like structure with biphenyl building blocks and exhibits exceptional thermal and hydrothermal stabilities. Herein, we computationally design new PAFs by introducing polar organic groups to the biphenyl unit and then investigate their separating power toward CO(2) by using grand-canonical Monte Carlo (GCMC) simulations. Among these functional PAFs, we found that tetrahydrofuran-like ether-functionalized PAF-1 shows higher adsorption capacity for CO(2) at 1 bar and 298 K (10 mol per kilogram of adsorbent) and also much higher selectivities for CO(2)/CH(4), CO(2)/N(2), and CO(2)/H(2) mixtures when compared with the amine functionality. The electrostatic interactions are found to play a dominant role in the high CO(2) selectivities of functional PAFs, as switching off atomic charges would decrease the selectivity by an order of magnitude. This work suggests that functionalizing porous frameworks with tetrahydrofuran-like ether groups is a promising way to increase CO(2) adsorption capacity and selectivity, especially at ambient pressures.

  9. A design and study of the effects of selectivity on binary separation in a four-zone simulated moving bed for systems with linear isotherms

    Directory of Open Access Journals (Sweden)

    M.A. Cremasco

    2003-06-01

    Full Text Available The simulated moving bed (SMB is potentially an economical method for the separation and purification of natural products because it is a continuous processes and can achieve higher productivity, higher product recovery, and higher purity than batch chromatographic processes. Despite the advantages of SMB, one of the challenges is to specify its zone flow rates and switching time. In this case it is possible to use the standing wave analysis. In this method, in a binary system, when certain concentration waves are confined to specific zones, high product purity and yield can be assured. Appropriate zone flow rates, zone lengths and step time are chosen to achieve standing waves. In this study the effects of selectivity on yield, throughput, solvent consumption, port switching time, and product purity for a binary system are analyzed. The results show that for a given selectivity the maximum throughput decreases with increasing yield, while solvent consumption and port switching time increase with increasing yield. To achieve the same purity and yield, a system with higher selectivity has a higher throughput and lower solvent consumption.

  10. Influence study of flow separation on the nozzle vibration response

    Directory of Open Access Journals (Sweden)

    Geng Li

    2016-06-01

    Full Text Available In the present paper, the vibration response difference of the upper stage nozzle with higher expansion ratio between ground and altitude simulation hot-firing test is analyzed. It indicates that the acceleration response of the nozzle under ground hot-firing test is much higher than that of the altitude condition. In order to find the essential reason, the experimental and numerical simulation studies of the flow separation are developed by using the test engine nozzle. The experimental data show that the nozzle internal flow occurred flow separation and the divergence cone internal wall pressure pulsation increased significantly downstream from the separation location. The numerical simulation and experimental results indicate that the increase of internal wall pressure and turbulence pulsating pressure are the substantial reason of vibration response increasing aggravatingly during the ground firing test.

  11. A molecular dynamics simulation study decodes the early stage of the disassembly process abolishing the human SAMHD1 function

    Science.gov (United States)

    Cardamone, Francesca; Iacovelli, Federico; Chillemi, Giovanni; Falconi, Mattia; Desideri, Alessandro

    2017-05-01

    The human sterile alpha motif SAM and HD domain-containing protein 1 (SAMHD1) restricts in non-cycling cells type the infection of a large range of retroviruses including HIV-1, reducing the intracellular pool concentration of deoxynucleoside triphosphates (dNTPs) required for the reverse transcription of the viral genome. The enzyme is in equilibrium between different forms depending on bound cofactors and substrate. In this work, two SAMHD1 three-dimensional models have been investigated through classical molecular dynamics simulation, to define the role of cofactors and metal ions in the association of the tetrameric active form. A detailed analysis of the inter-subunit interactions, taking place at the level of helix 13, indicates that removal of metal ions and cofactors induces an asymmetric loosening of the monomer-monomer interface leading to the formation of a loose tetramer where the two dimeric interfaces are weakened in different way.

  12. A separator

    Energy Technology Data Exchange (ETDEWEB)

    Prokopyuk, S.G.; Dyachenko, A.Ye.; Mukhametov, M.N.; Prokopov, O.I.

    1982-01-01

    A separator is proposed which contains separating slanted plates and baffle plates installed at a distance to them at an acute angle to them. To increase the effectiveness of separating a gas and liquid stream and the throughput through reducing the secondary carry away of the liquid drops and to reduce the hydraulic resistance, as well, openings are made in the plates. The horizontal projections of each opening from the lower and upper surfaces of the plate do not overlap each other.

  13. Development of technologies on innovative-simplified nuclear power plant using high-efficiency steam injectors. (3) Separate two-phase flow analysis for multi-stage steam injector

    International Nuclear Information System (INIS)

    Narabayashi, T.; Iwaki, C.; Mori, M.; Ohmori, S.

    2004-01-01

    A steam injector (SI) is a simple, compact and passive pump and also acts as an high-performance direct-contact compact heater. This provides SI with capability to serve also as a direct-contact feedwater heater that heats up feedwater by using extracted steam from the turbine. To develop high performance compact feedwater heater, it is necessary to quantify the characteristics between physical properties of the flow field. We carried out experiments to observe the internal behavior of the water jet using a laser doppler velocimetry. It's performance depends on the phenomena of steam condensation onto the water jet surface and heat transfer in the water jet due to turbulence on to the phase-interface. The analysis was also conducted by using CFD code embedded separate two-phase flow models and confirmed that the steam has a high-performance direct-contact heater that was suitable for compact feedwater heater. As it is compact equipment, SI is expected to bring about great simplification and materials-saving effects, while its simple structure ensures high reliability of its operation, thereby greatly contributing to the simplification of the power plant by replacing all low-pressure feedwater heaters with the four-stage SI system, having steam extraction pressures equal to those for the existing ABWR system. (author)

  14. Gender differences in Salix myrsinifolia at the pre-reproductive stage are little affected by simulated climatic change

    Energy Technology Data Exchange (ETDEWEB)

    Nybakken, L.; Julkunen-Tiitto, R. [Univ. of Eastern Finland. Dept. of Biology, Joensuu (Finland)

    2013-04-15

    Females of dioecious species are known often to prioritize defense, while males grow faster. As climatic change is known to influence both growth and defense in plants, it would be important to know whether it affects the sexes of dioecious species differently. This could have impacts on future sex ratios in nature. We grew four clones of each sex of Salix myrsinifolia in greenhouse chambers under ambient conditions, enhanced temperature, enhanced CO{sub 2} or enhanced temperature? + enhanced CO{sub 2}. The females had the greatest growth and also the highest levels of phenolic compounds in twigs, while in leaves some compounds were higher in males, some in females. Enhanced CO{sub 2} increased growth equally in both sexes, while growth was not affected by elevated temperature. Phenolic compounds in twigs were, however, lowered under elevated temperature. The gender differences were not strongly affected by the simulated climatic changes, but the effects seen on some highly concentrated compounds may be important. We interpret the intensive growth at pre-reproductive phase as a strategy in females to get an initial advantage before later periods with fewer resources available for growth. (Author)

  15. The effects of simulated solar UVB radiation on early developmental stages of the Northwestern Salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, Robin D.; Little, Edward E.; Pearl, Christopher A.; Hoffman, Robert L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290–320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66% of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation.

  16. Isotope separation

    International Nuclear Information System (INIS)

    Eerkens, J.W.

    1979-01-01

    A method of isotope separation is described which involves the use of a laser photon beam to selectively induce energy level transitions of an isotope molecule containing the isotope to be separated. The use of the technique for 235 U enrichment is demonstrated. (UK)

  17. Effects of simulated solar UVB radiation on early developmental stages of the northwestern salamander (Ambystoma gracile) from three lakes

    Science.gov (United States)

    Calfee, R.D.; Little, E.E.; Pearl, C.A.; Hoffman, R.L.

    2010-01-01

    Solar ultraviolet radiation (UV) has received much attention as a factor that could play a role in amphibian population declines. UV can be hazardous to some amphibians, but the resultant effects depend on a variety of environmental and behavioral factors. In this study, the potential effects of UV on the Northwestern Salamander, Ambystoma gracile, from three lakes were assessed in the laboratory using a solar simulator. We measured the survival of embryos and the survival and growth of larvae exposed to four UV treatments in controlled laboratory studies, the UV absorbance of egg jelly, oviposition depths in the lakes, and UV absorbance in water samples from the three lakes. Hatching success of embryos decreased in the higher UV treatments as compared to the control treatments, and growth of surviving larvae was significantly reduced in the higher UVB irradiance treatments. The egg jelly exhibited a small peak of absorbance within the UVB range (290-320 nm). The magnitude of UV absorbance differed among egg jellies from the three lakes. Oviposition depths at the three sites averaged 1.10 m below the water surface. Approximately 66 of surface UVB radiation was attenuated at 10-cm depth in all three lakes. Results of this study indicate that larvae may be sensitive to UVB exposure under laboratory conditions; however, in field conditions the depths of egg deposition in the lakes, absorbance of UV radiation by the water column, and the potential for behavioral adjustments may mitigate severe effects of UV radiation. Copyright 2010 Society for the Study of Amphibians and Reptiles.

  18. Highly porous ionic rht metal-organic framework for H2 and CO2 storage and separation: A molecular simulation study

    KAUST Repository

    Babarao, Ravichandar

    2010-07-06

    The storage and separation of H2 and CO2 are investigated in a highly porous ionic rht metal-organic framework (rht-MOF) using molecular simulation. The rht-MOF possesses a cationic framework and charge-balancing extraframework NO3 - ions. Three types of unique open cages exist in the framework: rhombicuboctahedral, tetrahedral, and cuboctahedral cages. The NO3 - ions exhibit small mobility and are located at the windows connecting the tetrahedral and cuboctahedral cages. At low pressures, H2 adsorption occurs near the NO 3 - ions that act as preferential sites. With increasing pressure, H2 molecules occupy the tetrahedral and cuboctahedral cages and the intersection regions. The predicted isotherm of H2 at 77 K agrees well with the experimental data. The H2 capacity is estimated to be 2.4 wt % at 1 bar and 6.2 wt % at 50 bar, among the highest in reported MOFs. In a four-component mixture (15:75:5:5 CO2/H 2/CO/CH4) representing a typical effluent gas of H 2 production, the selectivity of CO2/H2 in rht-MOF decreases slightly with increasing pressure, then increases because of cooperative interactions, and finally decreases as a consequence of entropy effect. By comparing three ionic MOFs (rht-MOF, soc-MOF, and rho-ZMOF), we find that the selectivity increases with increasing charge density or decreasing free volume. In the presence of a trace amount of H2O, the interactions between CO2 and NO3 - ions are significantly shielded by H2O; consequently, the selectivity of CO 2/H2 decreases substantially. © 2010 American Chemical Society.

  19. A Proposal Of Simulation Model Of A Wind-Steering System For Sailing Yachts, Based On Single-Stage Servo-Pendulum Coupled With Main Rudder

    Directory of Open Access Journals (Sweden)

    Piętak Andrzej

    2015-04-01

    Full Text Available The aim of this study was to investigate possible application of fast design prototyping methods for wind-steering systems used in offshore sailing yachts. The development of such methods would help to speed up the construction work and reduce the scope of necessary experimental research, prior to implementation of the system. In the present work, based on an analysis of existing designs of windvane systems, a preliminary selection of the system configuration has been undertaken, in terms of a compromise between efficiency, performance, and design complexity. Construction design of a single-stage, servo – pendulum system, has been developed by using the Autodesk Inventor design package. Next, based on the design data, a simulation model of the system, has been produced by using Matlab - Simulink software and SimMechanics library. The model was further verified in terms of kinematics mapping with the use of Matlab visualization tools.

  20. Simulator program as a form of implementation of electronic teaching tools for self-study of foreign students at the stage of pre-university training

    Directory of Open Access Journals (Sweden)

    Andriy O. Savel'ev

    2015-06-01

    Full Text Available Questions of empowerment the organization of classroom and extracurricular self-study of foreign students at the stage of pre-university training through the implementation of electronic teaching tools as a component of computer training facilities in educational process are considered. Classification of modern electronic teaching tools as a component of computer hardware training, developed on the basis of modern information and communication technologies is offered. Version of program-simulator "Introductory course" is offered. The program is created by means of WEB-programming and uses training material of introductory course. Introductory course is one of the most important elements of teaching of scientific style of speech within the language training for the foreign students at the preparatory faculty.

  1. Theory of Oxygen Tracer Diffusion Along Grain Boundaries and in the Bulk in Two-Stage Oxidation Experiments. Part III: Monte-Carlo Simulations

    Science.gov (United States)

    Mishin, Yuri; Schimmelpfennig, Jörg; Borchardt, Günter

    1997-09-01

    In Parts I and II of this work we developed a model of oxygen ^{18}O tracer diffusion in a growing polycrystalline oxide film with parallel grain boundaries. In this paper we solve the basic equations of the model numerically using the Monte-Carlo approach. We introduce a new simulation technique that takes into account the finite-size effect, the film growth, the effect of the oxygen chemical potential gradient across the film, and other factors. We apply this technique for the simulation of the most important cases encountered in two-stage oxidation experiments. The oxygen tracer profiles obtained demonstrate good agreement with the previous theoretical analysis, the finite-difference solution of the problem, and exact analytical solutions when available. We discuss possible extensions of the simulation method to provide a more realistic description of the oxide growth. Dans la partie I et II de ces travaux, nous avons développé un modèle pour la diffusion du traceur ^{18}O dans un film d'oxyde croissant avec des joints de grains parallèles. Dans cet article, nous donnons une solution numérique des équations fondamentales par la méthode de Monte-Carlo. Nous introduisons une nouvelle méthode de simulation qui tient compte de la géométrie de couches minces, du gradient du potentiel chimique de l'oxygène à travers la couche et d'autres paramètres. Nous utilisons cette technique afin de simuler les cas les plus fréquement rencontés dans des expériences d'oxydation à deux étapes. Les profils de traceurs obtenus sont en bon accord avec l'analyse théorique antérieur, avec les profils calculés par la méthode des différences finies et, s'il y en a, avec des solutions analytiques. Nous discutons l'extension éventuelle de notre méthode de simulation afin de fournir une description plus réaliste de la croissance d'une couche d'oxyde.

  2. Turbine stage model

    International Nuclear Information System (INIS)

    Kazantsev, A.A.

    2009-01-01

    A model of turbine stage for calculations of NPP turbine department dynamics in real time was developed. The simulation results were compared with manufacturer calculations for NPP low-speed and fast turbines. The comparison results have shown that the model is valid for real time simulation of all modes of turbines operation. The model allows calculating turbine stage parameters with 1% accuracy. It was shown that the developed turbine stage model meets the accuracy requirements if the data of turbine blades setting angles for all turbine stages are available [ru

  3. CENTRIFUGAL SEPARATORS

    Science.gov (United States)

    Skarstrom, C.

    1959-03-10

    A centrifugal separator is described for separating gaseous mixtures where the temperature gradients both longitudinally and radially of the centrifuge may be controlled effectively to produce a maximum separation of the process gases flowing through. Tbe invention provides for the balancing of increases and decreases in temperature in various zones of the centrifuge chamber as the result of compression and expansions respectively, of process gases and may be employed effectively both to neutralize harmful temperature gradients and to utilize beneficial temperaturc gradients within the centrifuge.

  4. A simulation study on performance evaluation of single-stage LiBr–H2O vapor absorption heat pump for chip cooling

    Directory of Open Access Journals (Sweden)

    Manu S.

    2016-12-01

    Full Text Available The growth of Lithium Bromide–Water (LiBr–H2O absorption based heat pump is encouraged for the necessity of extracting high heat from the electronic chips. This paper presents a simulation study of single-stage LiBr–H2O vapor absorption heat pump for chip cooling. In this study, a detailed thermodynamic analysis of the single-stage LiBr–H2O vapor absorption heat pump for chip cooling in the nonexistence of solution heat exchanger was performed and a user-friendly graphical user interface (GUI package including visual components was developed by using MATlab (2008b. The influence of chip temperature on COP (Coefficient of Performance, flow rates and conductance was examined by using the developed package. The model is validated by using the values available in the literature and indicates that there is a greater reduction in the absorber load. The influence of chip temperature on the performance and thermal loads of individual components was studied and it was concluded that, COP increases from 0.7145 to 0.8421 with an increase in chip temperature.

  5. Separated Shoulder

    Science.gov (United States)

    ... ligaments that hold your collarbone (clavicle) to your shoulder blade. In a mild separated shoulder, the ligaments might ... the ligaments that hold your collarbone to your shoulder blade. Risk factors Participating in contact sports, such as ...

  6. Isotopic separation

    International Nuclear Information System (INIS)

    Chen, C.L.

    1979-01-01

    Isotopic species in an isotopic mixture including a first species having a first isotope and a second species having a second isotope are separated by selectively exciting the first species in preference to the second species and then reacting the selectively excited first species with an additional preselected radiation, an electron or another chemical species so as to form a product having a mass different from the original species and separating the product from the balance of the mixture in a centrifugal separating device such as centrifuge or aerodynamic nozzle. In the centrifuge the isotopic mixture is passed into a rotor where it is irradiated through a window. Heavier and lighter components can be withdrawn. The irradiated mixture experiences a large centrifugal force and is separated in a deflection area into lighter and heavier components. (UK)

  7. Isotopic separation

    International Nuclear Information System (INIS)

    Castle, P.M.

    1979-01-01

    This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

  8. Separations chemistry

    International Nuclear Information System (INIS)

    Anon.

    1976-01-01

    Results of studies on the photochemistry of aqueous Pu solutions and the stability of iodine in liquid and gaseous CO 2 are reported. Progress is reported in studies on: the preparation of macroporous bodies filled with oxides and sulfides to be used as adsorbents; the beneficiation of photographic wastes; the anion exchange adsorption of transition elements from thiosulfate solutions; advanced filtration applications of energy significance; high-resolution separations; and, the examination of the separation agents, octylphenylphosphoric acid (OPPA) and trihexyl phosphate (THP)

  9. Product separator

    International Nuclear Information System (INIS)

    Welsh, R.A.; Deurbrouck, A.W.

    1976-01-01

    A description is given of a secondary light sensitive photoelectric product separator for use with a primary product separator that concentrates a material so that it is visually distinguishable from adjacent materials. The concentrate separation is accomplished first by feeding the material onto a vibratory inclined surface with a liquid flow, such as a wet concentrating table. Vibrations generally perpendicular to the stream direction of flow cause the concentrate to separate from its mixture according to its color. When the concentrate and its surrounding stream reach the recovery end of the table, a detecting device notes the line of color demarcation and triggers a signal if it differs from a normal condition. If no difference is noted, nothing moves on the second separator. However, if a difference is detected in the constant monitoring of the color line's location, a product splitter and recovery unit normally positioned near the color line at the recovery end, moves to a new position. In this manner the selected separated concentrate is recovered at a maximum rate regardless of variations in the flow stream or other conditions present

  10. Simulation

    DEFF Research Database (Denmark)

    Gould, Derek A; Chalmers, Nicholas; Johnson, Sheena J

    2012-01-01

    Recognition of the many limitations of traditional apprenticeship training is driving new approaches to learning medical procedural skills. Among simulation technologies and methods available today, computer-based systems are topical and bring the benefits of automated, repeatable, and reliable...... performance assessments. Human factors research is central to simulator model development that is relevant to real-world imaging-guided interventional tasks and to the credentialing programs in which it would be used....

  11. Separable algebras

    CERN Document Server

    Ford, Timothy J

    2017-01-01

    This book presents a comprehensive introduction to the theory of separable algebras over commutative rings. After a thorough introduction to the general theory, the fundamental roles played by separable algebras are explored. For example, Azumaya algebras, the henselization of local rings, and Galois theory are rigorously introduced and treated. Interwoven throughout these applications is the important notion of étale algebras. Essential connections are drawn between the theory of separable algebras and Morita theory, the theory of faithfully flat descent, cohomology, derivations, differentials, reflexive lattices, maximal orders, and class groups. The text is accessible to graduate students who have finished a first course in algebra, and it includes necessary foundational material, useful exercises, and many nontrivial examples.

  12. Isotope separation

    International Nuclear Information System (INIS)

    Bartlett, R.J.; Morrey, J.R.

    1978-01-01

    A method and apparatus is described for separating gas molecules containing one isotope of an element from gas molecules containing other isotopes of the same element in which all of the molecules of the gas are at the same electronic state in their ground state. Gas molecules in a gas stream containing one of the isotopes are selectively excited to a different electronic state while leaving the other gas molecules in their original ground state. Gas molecules containing one of the isotopes are then deflected from the other gas molecules in the stream and thus physically separated

  13. Isotopic separation

    International Nuclear Information System (INIS)

    Chen, C.

    1981-01-01

    Method and apparatus for separating isotopes in an isotopic mixture of atoms or molecules by increasing the mass differential among isotopic species. The mixture containing a particular isotope is selectively irradiated so as to selectively excite the isotope. This preferentially excited species is then reacted rapidly with an additional preselected radiation, an electron or another chemical species so as to form a product containing the specific isotope, but having a mass different than the original species initially containing the particular isotope. The product and the remaining balance of the mixture is then caused to flow through a device which separates the product from the mixture based upon the increased mass differential

  14. Simulation

    CERN Document Server

    Ross, Sheldon

    2006-01-01

    Ross's Simulation, Fourth Edition introduces aspiring and practicing actuaries, engineers, computer scientists and others to the practical aspects of constructing computerized simulation studies to analyze and interpret real phenomena. Readers learn to apply results of these analyses to problems in a wide variety of fields to obtain effective, accurate solutions and make predictions about future outcomes. This text explains how a computer can be used to generate random numbers, and how to use these random numbers to generate the behavior of a stochastic model over time. It presents the statist

  15. Comparison of gas membrane separation cascades using conventional separation cell and two-unit separation cells

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Morisue, Tetsuo; Ozaki, Osamu; Miyauchi, Terukatsu.

    1978-01-01

    The adoption of two-unit separation cells in radioactive rare gas membrane separation equipment enhances the separation factor, but increases the required membrane area and compressive power. An analytical economic evaluation was undertaken to compare the conventional separation cell with the two-unit separation cells, adopting as parameters the number of cascade stages, the membrane area and the operating power requirements. This paper describes the models used for evaluating the separation performance and the economics of cascade embodying these different concepts of separation cell taken up for study, and the results obtained for the individual concepts are mutually compared. It proved that, in respect of the number required of cascade stages, of operating power requirements and of the annual expenditure, better performance could always be expected of the two-unit separation cells as compared with the conventional separation cell, at least in the range of parameters adopted in this study. As regards the minimum membrane area, the conventional separation cell and the series-type separation cell yielded almost the same values, with the parallel-type separation cell falling somewhat behind. (auth.)

  16. Influence of Geometric Parameters of the Hydrocyclone and Sand Concentration on the Water/Sand/Heavy-Oil Separation Process: Modeling and Simulation

    Directory of Open Access Journals (Sweden)

    F Farias

    2016-09-01

    Full Text Available In the oil exploitation, produced fluids are composed of oil, gas, water and sand (depending on the reservoir location. The presence of sand in flow oil leads to several industrial problems for example: erosion and accumulation in valves and pipeline. Thus, it is necessary to stop production for manual cleaning of equipments and pipes. These facts have attracted attention of academic and industrial areas, enabling the appearing of new technologies or improvement of the water/oil/sand separation process. One equipment that has been used to promote phase separation is the hydrocyclone due to high performance of separation and required low cost to installation and maintenance. In this sense, the purpose of this work is to study numerically the effect of geometric parameters (vortex finder diameter of the hydrocyclone and sand concentration on the inlet fluid separation process. A numerical solution of the governing equations was obtained by the ANSYS CFX-11 commercial code. Results of the streamlines, pressure drop and separation efficiency on the hydrocyclone are presented and analyzed. It was observed that the particles concentration and geometry affect the separation efficiency of the hydrocyclone.

  17. Isotope separation

    International Nuclear Information System (INIS)

    Coleman, G.H.; Bett, R.; Cuninghame, J.G.; Sims, H.

    1982-01-01

    In the separation of short-lived isotopes for medical usage, a solution containing sup(195m)Hg is contacted with vicinal dithiol cellulose which adsorbs and retains the sup(195m)Hg. sup(195m)Au is eluted from the vicinal dithiol cellulose by using a suitable elutant. The sup(195m)Au arises from the radioactive decay of the sup(195m)Hg. The preferred elutant is a solution containing CN - ion. (author)

  18. Gas separating

    Science.gov (United States)

    Gollan, Arye Z.

    1990-12-25

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing.

  19. Multiple stage railgun

    International Nuclear Information System (INIS)

    Aaland, K.; Hawke, R.S.; Scudder, J.K.

    1982-01-01

    A multiple stage magnetic railgun accelerator for accelerating a projectile by movement of a plasma arc along the rails. The railgun is divided into a plurality of successive rail stages which are sequentially energized by separate energy sources as the projectile moves through the bore of the railgun. Propagation of energy from an energized rail stage back towards the breech end of the railgun can be prevented by connection of the energy sources to the rails through isolation diodes. Propagation of energy from an energized rail stage back towards the breech end of the railgun can also be prevented by dividing the rails into electrically isolated rail sections. In such case means are used to extinguish the arc at the end of each energized stage and a fuse or laser device is used to initiate a new plasma arc in the next energized rail stage

  20. Power process with separation of CO{sub 2} through combustion in two stages - chemical looping combustion. Final report; Kraftprocess med avskiljning av CO{sub 2} genom foerbraenning i ett tvaastegsfoerfarande - chemical looping combustion. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Lyngfelt, Anders; Cho, Paul; Steenari, Britt-Marie; Langer, Vratislav; Eriksson, Sten; Mattisson, Tobias [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Energy Technology

    2005-06-15

    For combustion with CO{sub 2} capture, chemical-looping combustion (CLC) with inherent separation of CO{sub 2} is a promising technology. Two interconnected fluidized beds are used as reactors. In the fuel reactor, a gaseous fuel is oxidized by an oxygen carrier, e.g. metal oxide particles, producing carbon dioxide and water. The reduced oxygen carrier is then transported to the air reactor, where it is oxidized by air back to its original form before it is returned to the fuel reactor. The feasibility of using both natural iron ore and synthetic oxygen carriers based on oxides of iron, nickel, copper and manganese was determined. Oxygen carrier particles were produced by freeze granulation. To be able to study and compare the different types of oxygen carrier particles, a procedure for testing and evaluation was developed. The reactivity was evaluated in both fixed and fluidized bed laboratory reactors, simulating a CLC system by exposing the sample to alternating reducing and oxidizing conditions. In addition, the particles were characterized with respect to crushing strength, agglomeration, tendency for carbon deposition as well as chemical and physical parameters. The rates of reaction varied and were highly dependent upon the oxygen carrier used. For the natural iron ore it was found that a high yield of CH{sub 4} to CO{sub 2} was possible although the solid reactivity was relatively low. The reactivity of the freeze granulated particles were considerably higher, with the oxygen carriers based on nickel and copper having the highest reactivity in comparison to Fe and Mn based particles. However all of the investigated samples had a reactivity sufficient for use in a CLC of interconnected fluidized beds. The copper oxide particles agglomerated and may not be suitable as an oxygen carrier. Carbon formation and agglomeration was studied in detail, and the results suggest that neither of those should be a problem in this process, except for copper which

  1. Co-digestion and model simulations of source separated municipal organic waste with cattle manure under batch and continuously stirred tank reactors

    DEFF Research Database (Denmark)

    Tsapekos, Panagiotis; Kougias, Panagiotis; Kuthiala, Sidhant

    2018-01-01

    This study investigates the co-digestion of source separated municipal organic waste (SSMOW), pretreated using a biopulper, and cattle manure both in batch and continuous stirred tank reactors. The optimum co-digestion feeding mixture was consisted of 90% SSMOW and 10% cattle manure on organic...

  2. Particle separation

    International Nuclear Information System (INIS)

    Baker, C.A.

    1990-01-01

    Solid particles are separated from a liquid which also contains ferric hydroxide by subjecting the liquid to ultrasonic agitation from a transducer in order to break up the flocs so that they will pass with the liquid through a filter belt. The belt thus retains the solid particles without interference from the flocs. As shown the woven nylon belt collects rare radioactive solid particles from liquid and carries them under sensors. The belt is washed clean, with further ultrasonic agitation in a trough on its return run. (author)

  3. Isotope separation

    International Nuclear Information System (INIS)

    Rosevear, A.; Sims, H.E.

    1985-01-01

    sup(195m)Au for medical usage is separated from sup(195m)Hg in a solution containing ions of sup(195m)Hg by contacting the solution with an adsorbing agent to adsorb 195 Hgsup(H) thereon, followed by selective elution of sup(195m)Au generated by radioactive decay of the sup(195m)Hg. The adsorbing agent comprises a composite material in the form of an inert porous inorganic substrate (e.g. Kieselguhr),the pores of which are occupied by a hydrogel of a polysaccharide (e.g. agarose) carrying terminal thiol groups for binding Hgsup(H) ions. (author)

  4. Gas separating

    Science.gov (United States)

    Gollan, A.

    1988-03-29

    Feed gas is directed tangentially along the non-skin surface of gas separation membrane modules comprising a cylindrical bundle of parallel contiguous hollow fibers supported to allow feed gas to flow from an inlet at one end of a cylindrical housing through the bores of the bundled fibers to an outlet at the other end while a component of the feed gas permeates through the fibers, each having the skin side on the outside, through a permeate outlet in the cylindrical casing. 3 figs.

  5. Isotope separation

    International Nuclear Information System (INIS)

    Coleman, J.H.; Marks, T.J.

    1981-01-01

    A process for separating uranium isotopes is described which includes: preparing a volatile compound U-T, in which U is a mixture of uranium isotopes and T is a chemical moiety containing at least one organic or deuterated borohydride group, and which exhibits for at least one isotopic species thereof a fundamental, overtone or combination vibrational absorption excitation energy level at a frequency between 900 and 1100 cm -1 ; and irradiating the compound in the vapour phase with energy emitted by a radiation source at a frequency between 900 and 1100 cm -1 (e.g. a CO 2 laser). (author)

  6. Assessment against Experiments of Devolatilization and Char Burnout Models for the Simulation of an Aerodynamically Staged Swirled Low-NOx Pulverized Coal Burner

    Directory of Open Access Journals (Sweden)

    Marco Torresi

    2017-01-01

    Full Text Available In the next few years, even though there will be a continuous growth of renewables and a loss of the share of fossil fuel, energy production will still be strongly dependent on fossil fuels. It is expected that coal will continue to play an important role as a primary energy source in the next few decades due to its lower cost and higher availability with respect to other fossil fuels. However, in order to improve the sustainability of energy production from fossil fuels, in terms of pollutant emissions and energy efficiency, the development of advanced investigation tools is crucial. In particular, computational fluid dynamics (CFD simulations are needed in order to support the design process of low emission burners. Even if in the literature several combustion models can be found, the assessment of their performance against detailed experimental measurements on full-scale pulverized coal burners is lacking. In this paper, the numerical simulation of a full-scale low-NO x , aerodynamically-staged, pulverized coal burner for electric utilities tested in the 48 MW th plant at the Combustion Environment Research Centre (CCA - Centro Combustione e Ambiente of Ansaldo Caldaie S.p.A. in Gioia del Colle (Italy is presented. In particular, this paper is focused on both devolatilization and char burnout models. The parameters of each model have been set according to the coal characteristics without any tuning based on the experimental data. Thanks to a detailed description of the complex geometry of the actual industrial burner and, in particular, of the pulverized coal inlet distribution (considering the entire primary air duct, in order to avoid any unrealistic assumption, a correct selection of both devolatilization and char burnout models and a selection of suited parameters for the NO x modeling, accurate results have been obtained in terms of NO x formation. Since the model parameters have been evaluated a priori, the numerical approach proposed

  7. Assistive peripheral phosphene arrays deliver advantages in obstacle avoidance in simulated end-stage retinitis pigmentosa: a virtual-reality study

    Science.gov (United States)

    Zapf, Marc Patrick H.; Boon, Mei-Ying; Lovell, Nigel H.; Suaning, Gregg J.

    2016-04-01

    Objective. The prospective efficacy of peripheral retinal prostheses for guiding orientation and mobility in the absence of residual vision, as compared to an implant for the central visual field (VF), was evaluated using simulated prosthetic vision (SPV). Approach. Sighted volunteers wearing a head-mounted display performed an obstacle circumvention task under SPV. Mobility and orientation performance with three layouts of prosthetic vision were compared: peripheral prosthetic vision of higher visual acuity (VA) but limited VF, of wider VF but limited VA, as well as centrally restricted prosthetic vision. Learning curves using these layouts were compared fitting an exponential model to the mobility and orientation measures. Main results. Using peripheral layouts, performance was superior to the central layout. Walking speed with both higher-acuity and wider-angle layouts was 5.6% higher, and mobility errors reduced by 46.4% and 48.6%, respectively, as compared to the central layout. The wider-angle layout yielded the least number of collisions, 63% less than the higher-acuity and 73% less than the central layout. Using peripheral layouts, the number of visual-scanning related head movements was 54.3% (higher-acuity) and 60.7% (wider-angle) lower, as compared to the central layout, and the ratio of time standing versus time walking was 51.9% and 61.5% lower, respectively. Learning curves did not differ between layouts, except for time standing versus time walking, where both peripheral layouts achieved significantly lower asymptotic values compared to the central layout. Significance. Beyond complementing residual vision for an improved performance, peripheral prosthetic vision can effectively guide mobility in the later stages of retinitis pigmentosa (RP) without residual vision. Further, the temporal dynamics of learning peripheral and central prosthetic vision are similar. Therefore, development of a peripheral retinal prosthesis and early implantation to

  8. Engineering model of the electric drives of separation device for simulation of automatic control systems of reactive power compensation by means of serially connected capacitors

    Science.gov (United States)

    Juromskiy, V. M.

    2016-09-01

    It is developed a mathematical model for an electric drive of high-speed separation device in terms of the modeling dynamic systems Simulink, MATLAB. The model is focused on the study of the automatic control systems of the power factor (Cosφ) of an actuator by compensating the reactive component of the total power by switching a capacitor bank in series with the actuator. The model is based on the methodology of the structural modeling of dynamic processes.

  9. Isotope separation

    International Nuclear Information System (INIS)

    Bett, R.; Sims, H.E.; Cuninghame, J.G.

    1983-01-01

    sup(195m)Au is separated from sup(195m)Hg in a solution containing ions of sup(195m)Hg, wherein sup(195m)Au is generated by radioactive decay of the sup(195m)Hg, by contacting the solution with an adsorbing agent to adsorb the sup(195m)Hg as Hg ++ ions followed by elution of sup(195m)Au arising from said radioactive decay. The adsorbing agent is 3-thio-2-hydroxypropyl-ether-Sepharose (R.T.M.); sup(195m)Au may be prepared in this way in a medical isotope generator and is suitable for use in gamma-scan studies of heart action. (author)

  10. Stage design

    International Nuclear Information System (INIS)

    Shacter, J.

    1975-01-01

    A method is described of cycling gases through a plurality of diffusion stages comprising the steps of admitting the diffused gases from a first diffusion stage into an axial compressor, simultaneously admitting the undiffused gases from a second diffusion stage into an intermediate pressure zone of said compressor corresponding in pressure to the pressure of said undiffused gases, and then admitting the resulting compressed mixture of diffused and undiffused gases into a third diffusion stage

  11. The Swarm End-to-End mission simulator study: A demonstration of separating the various contributions to Earth's magnetic field using synthetic data

    DEFF Research Database (Denmark)

    Olsen, Nils; Haagmans, R.; Sabaka, T.J.

    2006-01-01

    by improving our understanding of the Earth's interior and climate. An End-to-End mission performance simulation was carried out during Phase A of the mission, with the aim of analyzing the key system requirements, particularly with respect to the number of Swarm satellites and their orbits related...

  12. Stage theta pinch experiments

    International Nuclear Information System (INIS)

    Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

    1975-01-01

    The Staged Theta Pinch program is designed to study the technological and physics problems associated with producing fat plasmas and separating the implosion heating from the adiabatic compression. Several methods of implosion heating are discussed. Circuit diagrams and theoretical magnetic field behavior are described for the STP and resonant heating experiments. (MOW)

  13. Nano-scale study of phase separation in ferrite of long term thermally aged Mo-bearing duplex stainless steels - Atom probe tomography and Monte Carlo simulation

    International Nuclear Information System (INIS)

    Pareige, C.; Emo, J.; Pareige, P.; Saillet, S.; Domain, C.

    2015-01-01

    Duplex stainless steels (DSS), used in primary circuit of Pressurised Water Reactor (PWR), are prone to thermal ageing at service temperature, typically between 286 and 323 C. degrees. This ageing is due to the ferrite decomposition via two kinds of phase transformations: spinodal decomposition into Fe rich α zones and Cr rich α' zones and precipitation of G-phase enriched in Ni, Si, Mn and Mo. It has been shown by atom probe tomography (APT) that the G-phase particles form at the interface between α and α' regions thereby demonstrating that α-α' decomposition and G-phase precipitation are highly dependent. The synergy between the two decomposition processes should be related to both the thermodynamics of the system and the diffusion mechanisms active during ageing. This can be studied by atomistic kinetic Monte Carlo (AKMC) with a model that can reproduce the phase transformations which take place in ferrite of duplex stainless steels. This paper presents the first simulations of the kinetics of spinodal decomposition and G-phase precipitation occurring in ferrite of duplex stainless steels. The kinetics was simulated using a simple but effective atomic kinetic Monte Carlo model in a ternary alloy. The simulations reproduced the α/α' spinodal structure with precipitates at the α/α' interface. The comparison of simulated results with experiments shows that the simulations quantitatively reproduce the kinetics of phase transformation and the synergy observed experimentally between the spinodal decomposition and G-phase precipitation: the time evolution of the wavelength of the spinodal decomposition and the radius of G-phase precipitates were quantitatively reproduced. The simulations endorse the assumption that G-phase precipitation mainly results from the rejection of G-formers from α and α' domains. By following the vacancy pathway during simulation, we show that coarsening of the G-phase precipitates must proceed via

  14. Lithium isotopic separation: preliminary studies

    International Nuclear Information System (INIS)

    Macedo, Sandra Helena Goulart de

    1998-01-01

    In order to get the separation of natural isotopes of lithium by electrolytic amalgamation, an electrolytic cell with a confined mercury cathode was used to obtain data for the design of a separation stage. The initial work was followed by the design of a moving mercury cathode electrolytic cell and three experiments with six batches stages were performed for the determination of the elementary separation factor. The value obtained, 1.053, was ill agreement: with the specialized literature. It was verified in all experiments that the lithium - 6 isotope concentrated in the amalgam phase and that the lithium - 7 isotope concentrated in the aqueous phase. A stainless-steel cathode for the decomposition of the lithium amalgam and the selective desamalgamation were also studied. In view of the results obtained, a five stages continuous scheme was proposed. (author)

  15. Development of Constraint Force Equation Methodology for Application to Multi-Body Dynamics Including Launch Vehicle Stage Seperation

    Science.gov (United States)

    Pamadi, Bandu N.; Toniolo, Matthew D.; Tartabini, Paul V.; Roithmayr, Carlos M.; Albertson, Cindy W.; Karlgaard, Christopher D.

    2016-01-01

    The objective of this report is to develop and implement a physics based method for analysis and simulation of multi-body dynamics including launch vehicle stage separation. The constraint force equation (CFE) methodology discussed in this report provides such a framework for modeling constraint forces and moments acting at joints when the vehicles are still connected. Several stand-alone test cases involving various types of joints were developed to validate the CFE methodology. The results were compared with ADAMS(Registered Trademark) and Autolev, two different industry standard benchmark codes for multi-body dynamic analysis and simulations. However, these two codes are not designed for aerospace flight trajectory simulations. After this validation exercise, the CFE algorithm was implemented in Program to Optimize Simulated Trajectories II (POST2) to provide a capability to simulate end-to-end trajectories of launch vehicles including stage separation. The POST2/CFE methodology was applied to the STS-1 Space Shuttle solid rocket booster (SRB) separation and Hyper-X Research Vehicle (HXRV) separation from the Pegasus booster as a further test and validation for its application to launch vehicle stage separation problems. Finally, to demonstrate end-to-end simulation capability, POST2/CFE was applied to the ascent, orbit insertion, and booster return of a reusable two-stage-to-orbit (TSTO) vehicle concept. With these validation exercises, POST2/CFE software can be used for performing conceptual level end-to-end simulations, including launch vehicle stage separation, for problems similar to those discussed in this report.

  16. Optics of mass separator I

    International Nuclear Information System (INIS)

    Balestrini, S.J.

    1981-07-01

    The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear and angular magnifications, and the dispersion. The possibility of converting the magnet into a tunable unit by means of current-carrying elements in the gap is demonstrated. The feasibility of correction coils constructed from printed circuit board is shown

  17. Optics of mass separator I

    Energy Technology Data Exchange (ETDEWEB)

    Balestrini, S.J.

    1981-07-01

    The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear and angular magnifications, and the dispersion. The possibility of converting the magnet into a tunable unit by means of current-carrying elements in the gap is demonstrated. The feasibility of correction coils constructed from printed circuit board is shown.

  18. Centrifugal separator cascade connected in zigzag manner

    International Nuclear Information System (INIS)

    Kai, Tsunetoshi; Inoue, Yoshiya; Oya, Akio; Nagakura, Masaaki.

    1974-01-01

    Object: To effectively accommodate centrifugal separators of the entire cascade within the available space in a plant by freely selecting perpendicular direction of connection of the centrifugal separator. Structure: Centrifugal separators are connected in zigzag fashion by using a single header for each stage so that in a rectangular shape the entire cascade is arranged. (Kamimura, M.)

  19. Separation of a binary mixture by sequential centrifugal partition chromatography.

    Science.gov (United States)

    Hopmann, Elisabeth; Minceva, Mirjana

    2012-03-16

    Sequential centrifugal partition chromatography (sCPC) is a novel continuous cyclic liquid-liquid chromatographic separation technology. Each cycle of the process comprises two steps, which differ by the liquid phase used as mobile phase (upper or lower phase) and its flow direction. The feed is introduced continuously in the unit and two product streams are collected alternately, in each step of the cycle. In this work, the sCPC was modeled using the stage (cell) model. The model was used to simulate a separation of a model binary mixture consisting of pyrocatechol and hydroquinone. The solutes distribution constants, system hydrodynamics and mass transfer parameters were determined experimentally and implemented in the model. Furthermore, a parameter study (variation of the feed concentration and step times) was performed by experiments and simulation. A recently developed method was used to select the operating parameters of the sCPC unit. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Development of Relations of Stream Stage to Channel Geometry and Discharge for Stream Segments Simulated with Hydrologic Simulation Program-Fortran (HSPF), Chesapeake Bay Watershed and Adjacent Parts of Virginia, Maryland, and Delaware

    Science.gov (United States)

    Moyer, Douglas; Bennett, Mark

    2007-01-01

    The U.S. Geological Survey (USGS), U.S. Environmental Protection Agency (USEPA), Chesapeake Bay Program (CBP), Interstate Commission for the Potomac River Basin (ICPRB), Maryland Department of the Environment (MDE), Virginia Department of Conservation and Recreation (VADCR), and University of Maryland (UMD) are collaborating to improve the resolution of the Chesapeake Bay Regional Watershed Model (CBRWM). This watershed model uses the Hydrologic Simulation Program-Fortran (HSPF) to simulate the fate and transport of nutrients and sediment throughout the Chesapeake Bay watershed and extended areas of Virginia, Maryland, and Delaware. Information from the CBRWM is used by the CBP and other watershed managers to assess the effectiveness of water-quality improvement efforts as well as guide future management activities. A critical step in the improvement of the CBRWM framework was the development of an HSPF function table (FTABLE) for each represented stream channel. The FTABLE is used to relate stage (water depth) in a particular stream channel to associated channel surface area, channel volume, and discharge (streamflow). The primary tool used to generate an FTABLE for each stream channel is the XSECT program, a computer program that requires nine input variables used to represent channel morphology. These input variables are reach length, upstream and downstream elevation, channel bottom width, channel bankfull width, channel bankfull stage, slope of the floodplain, and Manning's roughness coefficient for the channel and floodplain. For the purpose of this study, the nine input variables were grouped into three categories: channel geometry, Manning's roughness coefficient, and channel and floodplain slope. Values of channel geometry for every stream segment represented in CBRWM were obtained by first developing regional regression models that relate basin drainage area to observed values of bankfull width, bankfull depth, and bottom width at each of the 290 USGS

  1. Separation of Hydrogen Isotopes by Palladium Alloy Membranes Separator

    International Nuclear Information System (INIS)

    Jiangfeng, S.; Deli, L.; Yifu, X.; Congxian, L.; Zhiyong, H.

    2007-01-01

    Full text of publication follows: Separation of hydrogen isotope with palladium alloy membranes is one of the promising methods for hydrogen isotope separation. It has several advantages, such as high separation efficiency, smaller tritium inventory, simple separation device, ect. Limited by the manufacture of membrane and cost of gas transportation pump, this method is still at the stage of conceptual study. The relationship between separation factors and temperatures, feed gas components, split ratios have not been researched in detail, and the calculated results of cascade separation have not been validated with experimental data. In this thesis, a palladium alloy membrane separator was designed to further study its separation performance between H 2 and D 2 . The separation factor of the single stage was affected by the temperature, the feed gas component, the split ratio and the gas flow rate, etc. The experimental results showed that the H 2 -D 2 separation factor decreased with the increasing of temperature. On the temperature from 573 K to 773 K, when the feed rate was 5 L/min, the separation factor of 66.2%H 2 - 33.8%D 2 decreased from 2.09 to 1.85 when the split ratio was 0.1 and from 1.74 to 1.52 when the split ratio was 0.2.The separation factor also decreased with the increasing of split ratio. At 573 K and the feed rate of 5 L/min, the separation factor of 15.0%H 2 and 85.0%D 2 decreased from 2.43 to 1.35 with the increasing of split ratio from 0.050 to 0.534,and for 66.2%H 2 -33.8%D 2 , the separation factor decreased from 2.87 to 1.30 with the increasing of split ratio from 0.050 to 0.688. When the separation factor was the biggest, the flow rate of feed gas was in a perfect value. To gain a best separation performance, perfect flow rate, lower temperature and reflux ratio should be chosen. (authors)

  2. Trading stages

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2012-01-01

    because they are hard to use and interpret, and tools for age and stage structured populations are missing. We present easily interpretable expressions for the sensitivities and elasticities of life expectancy to vital rates in age-stage models, and illustrate their application with two biological......Interest in stage-and age structured models has recently increased because they can describe quantitative traits such as size that are left out of age-only demography. Available methods for the analysis of effects of vital rates on lifespan in stage-structured models have not been widely applied...... examples. Much of our approach relies on trading of time and mortality risk in one stage for time and risk in others. Our approach contributes to the new framework of the study of age- and stage-structured biodemography....

  3. Multistage Electrophoretic Separators

    Science.gov (United States)

    Thomas, Nathan; Doyle, John F.; Kurk, Andy; Vellinger, John C.; Todd, Paul

    2006-01-01

    A multistage electrophoresis apparatus has been invented for use in the separation of cells, protein molecules, and other particles and solutes in concentrated aqueous solutions and suspensions. The design exploits free electrophoresis but overcomes the deficiencies of prior free-electrophoretic separators by incorporating a combination of published advances in mathematical modeling of convection, sedimentation, electro-osmotic flow, and the sedimentation and aggregation of droplets. In comparison with other electrophoretic separators, these apparatuses are easier to use and are better suited to separation in relatively large quantities characterized in the art as preparative (in contradistinction to smaller quantities characterized in the art as analytical). In a multistage electrophoretic separator according to the invention, an applied vertical steady electric field draws the electrically charged particles of interest from within a cuvette to within a collection cavity that has been moved into position of the cuvette. There are multiple collection cavities arranged in a circle; each is aligned with the cuvette for a prescribed short time. The multistage, short-migration-path character of the invention solves, possibly for the first time, the fluid-instability problems associated with free electrophoresis. The figure shows a prototype multistage electrophoretic separator that includes four sample stations and five collection stages per sample. At each sample station, an aqueous solution or suspension containing charged species to be separated is loaded into a cuvette, which is machined into a top plate. The apparatus includes a lower plate, into which 20 collection cavities have been milled. Each cavity is filled with an electrophoresis buffer solution. For the collection of an electrophoretic fraction, the lower plate is rotated to move a designated collection cavity into alignment with the opening of the cuvette. An electric field is then applied between a non

  4. The Swarm End-to-End mission simulator study: A demonstration of separating the various contributions to Earth's magnetic field using synthetic data

    DEFF Research Database (Denmark)

    Olsen, Nils; Haagmans, R.; Sabaka, T.J.

    2006-01-01

    Swarm, a satellite constellation to measure Earth's magnetic field with unpreceded accuracy, has been selected by ESA for launch in 2009. The mission will provide the best ever survey of the geomagnetic field and its temporal evolution, in order to gain new insights into the Earth system...... to the science objectives of Swarm. In order to be able to use realistic parameters of the Earth's environment, the mission simulation starts at January 1, 1997 and lasts until re-entry of the lower satellites five years later. Synthetic magnetic field values were generated for all relevant contributions...... to Earth's magnetic field: core and lithospheric fields, fields due to currents in the ionosphere and magnetosphere, due to their secondary, induced, currents in the oceans, lithosphere and mantle, and fields due to currents coupling the ionosphere and magnetosphere. Several independent methods were...

  5. Optical simulations for the S3 project - Super separator spectrometer - gamma-electron coincidence spectroscopy of a transfermium nucleus: the 251Md101

    International Nuclear Information System (INIS)

    Dechery, Fabien

    2012-01-01

    In analogy with the atomic closed shells giving rise to the stability and high ionisation energies of noble gases, nuclear physics also has its magic numbers of protons and neutrons which enhance nuclear structure stability. Knowledge of the structure of doubly-magic nuclei, both proton and neutron numbers, is crucial to parameterize theoretical models. The discovery of the next and ultimate magic numbers will provide a strong constraint on the many predictions. These two numbers are like the centre coordinates of an area of enhanced stability of the nuclear chart, well known as 'island of stability'. These superheavy nuclei only exist due to pure quantum shell effects. My thesis work deals with two distinct, but complementary, aspects of fundamental physics with the common goal of studying these extreme mass nuclei structure. The first part corresponds to the development of a next generation instrument for nuclear physics to allow synthesis and spectroscopy studies of superheavy nuclei: the Super Separator Spectrometer S 3 . This project will be installed at SPIRAL2 (GANIL) and has been approved by the French Research National Agency (ANR) within the EQUIPEX framework. It has been designed to take advantage of the high intensity heavy ion beam from the LINAC, giving access to a wide range of physical programs. The second part corresponds to the preparation, realisation and analysis of an experiment on 251-Mendelevium in which the very first prompt gamma-electron coincidence spectroscopy was performed for a transfermium nuclei. (author) [fr

  6. The isotopic contamination in electromagnetic isotope separators

    International Nuclear Information System (INIS)

    Cassignol, Ch.

    1959-01-01

    In the early years of isotope separation, and in particular electromagnetic isotope separation, needs for rapid results have conducted to empiric research. This paper describes fundamental research on the electromagnetic isotope separation to a better understanding of isotope separators as well as improving the performances. Focus has been made on the study of the principle of isotope contamination and the remedial action on the separator to improve the isotope separation ratio. In a first part, the author come back to the functioning of an electromagnetic separator and generalities on isotope contamination. Secondly, it describes the two stages separation method with two dispersive apparatus, an electromagnetic separation stage followed by an electrostatic separation stage, both separated by a diaphragm. The specifications of the electrostatic stage are given and its different settings and their consequences on isotope separation are investigated. In a third part, mechanisms and contamination factors in the isotope separation are discussed: natural isotope contamination, contamination by rebounding on the collector, contamination because of a low resolution, contamination by chromatism and diffusion effect, breakdown of condenser voltage. Analysis of experimental results shows the diffusion as the most important contamination factor in electromagnetic isotope separation. As contamination factors are dependent on geometric parameters, sector angle, radius of curvature in the magnetic field and clearance height are discussed in a fourth part. The better understanding of the mechanism of the different contamination factors and the study of influential parameters as pressure and geometric parameters lead to define a global scheme of isotope contamination and determinate optima separator design and experimental parameters. Finally, the global scheme of isotope contamination and hypothesis on optima specifications and experimental parameters has been checked during a

  7. Isotope separation apparatus

    International Nuclear Information System (INIS)

    Lyon, R.K.; Eisner, P.N.; Thomas, W.R.I.

    1983-01-01

    This application discloses a method for and an apparatus in which isotopes of an element in a compared are separated from each other while that compound, i.e., including a mixture of such isotopes, flows along a predetermined path. The apparatus includes a flow tube having a beginning and an end. The mixture of isotopes is introduced into the flow tube at a first introduction point between the beginning and the end thereof to flow the mixture toward the end thereof. A laser irradiates the flow tube dissociating compounds of a preselected one of said isotopes thereby converting the mixture in an isotopically selective manner. The dissociation products are removed from the tube at a first removal point between the first introduction point and the end. The dissociation product removed at the the first removal point are reconverted back into the comound thereby providing a first stage enriched compound. This first stage enriched compound is reintroduced into the flow tube at a second introduction point between the beginning thereof and the first introduction point. Further product is removed from the flow tube at a second removal point between the second introduction point and the first introduction point. The second introduction point is chosen so that the isotope composition of the first stage enriched compound is approximately the same as that of the compound in the flow tube

  8. Separation of mixed waste plastics via magnetic levitation.

    Science.gov (United States)

    Zhao, Peng; Xie, Jun; Gu, Fu; Sharmin, Nusrat; Hall, Philip; Fu, Jianzhong

    2018-03-02

    Separation becomes a bottleneck of dealing with the enormous stream of waste plastics, as most of the extant methods can only handle binary mixtures. In this paper, a novel method that based on magnetic levitation was proposed for separating multiple mixed plastics. Six types of plastics, i.e., polypropylene (PP), acrylonitrile butadiene styrene (ABS), polyamide 6 (PA6), polycarbonate (PC), polyethylene terephthalate (PET), and polytetrafluoroethylene (PTFE), were used to simulate the mixed waste plastics. The samples were mixed and immersed into paramagnetic medium that placed into a magnetic levitation configuration with two identical NdFeB magnets with like-poles facing each other, and Fourier transform infrared (FTIR) spectroscopy was employed to verify the separation outputs. Unlike any conventional separation methods such as froth flotation and hydrocyclone, this method is not limited by particle sizes, as mixtures of different size fractions reached their respective equilibrium positions in the initial tests. The two-stage separation tests demonstrated that the plastics can be completely separated with purities reached 100%. The method has the potential to be industrialised into an economically-viable and environmentally-friendly mass production procedure, since quantitative correlations are determined, and the paramagnetic medium can be reused indefinitely. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  10. Separation control on curved boundaries

    Science.gov (United States)

    Kamal Kumar, R.; Mathur, Manikandan

    2017-11-01

    Flow separation and its characteristics are an important consideration in the field of bluff body aerodynamics. Specifically, the location and slope of the separation, and the size of the re-circulation bubble that forms downstream of the bluff body significantly affect the resulting aerodynamic forces. Recent theories based on dynamical systems (Haller, 2004) have established criteria based on wall-based quantities that identify the location and slope of separation in unsteady flows. In this work, we adapt the closed-loop separation control algorithm proposed by Alam, Liu & Haller (2006) to curved boundaries, and demonstrate the effectiveness of the same via numerical simulations on the flow past a cylinder in the vortex-shedding regime. Using appropriately placed wall-based actuators that use inputs from shear stress sensors placed between the actuators, we demonstrate that the separation characteristics including the re-circulation bubble length, can be desirably modified.

  11. Magnetic Microfluidic Linear Halbach Array Configuration for Cell Separation

    Directory of Open Access Journals (Sweden)

    Saeed Omer

    2018-01-01

    Full Text Available The different type of blood entities like red blood cells (RBCs, white blood cell (WBCs and platelets counts is a critical point in routine medical tests. Circulating tumor cells (CTCs counting and analysing in the blood is indicative of the stage and origin of cancer in particular time. Here we are describing a proposed microfluidic device, used a magnetic means for CTCs separation from a blood or buffer sample. The device characterizations were simulated using COMSOL MULTIPHYSICS software as well as practically validated. Using a known spiked number of CTCs in the sample, the purity and recovery rate were calculated to be 93% and respectively.

  12. Effects of Endwall Geometry and Stacking on Two-Stage Supersonic Turbine Performance

    Science.gov (United States)

    Dorney, Daniel J.; Griffin, Lisa W.; Huber, Frank W.; Sondak, Douglas L.; Turner, Jim (Technical Monitor)

    2002-01-01

    The drive towards high-work turbines has led to designs which can be compact, transonic, supersonic, counter rotating, or use a dense drive gas. These aggressive designs can lead to strong secondary flows and airfoil flow separation. In many cases the secondary and separated flows can be minimized by contouring the hub/shroud endwalls and/or modifying the airfoil stacking. In this study, three-dimensional unsteady Navier-Stokes simulations were performed to study three different endwall shapes between the first-stage vanes and rotors, as well as two different stackings for the first-stage vanes. The predicted results indicate that changing the stacking of the first-stage vanes can significantly impact endwall separation (and turbine performance) in regions where the endwall profile changes.

  13. ITER isotope separation system

    International Nuclear Information System (INIS)

    Busigin, A.; Sood, S.K.; Kveton, O.K.; Sherman, R.H.; Anderson, J.L.

    1990-09-01

    This document presents the results of a study that examined the technical operating and economic viability of an alternative Isotope Separation System (ISS) design based on the distributed design concept. In the distributed design, the ISS is broken up into local independently operable subsystems matched to local processing requirements. The distributed design accepts the same feeds and produces essentially the same products as the reference design. The distributed design consists of two separate, independent subsystems. The first, called ISS-H, receives only protium-dominated streams and waste water from tritium extraction. It has two cryogenic distillation columns and can produce a 50 percent D, 50 percent T product since it lacks D/T separation capability. A final 80 percent T 2 concentration product can be obtained by blending the 50 percent T 2 stream from ISS-H with the more than 99 percent T 2 stream from the second subsystem, ISS-D. The second subsystem receives only deuterium-dominated feeds, which also contain some protium. ISS-D is as complex as the reference design, but smaller. Although each subsystem has some advantages, such as only two cryogenic distillation columns in ISS-H and better than 99 percent steady state T 2 product in ISS-D, the combined subsystems do not offer any real advantage compared to the reference IISS. The entire distributed ISS design has been simulated using Ontario Hydro's FLOSHEET steady state process simulator. Dynamic analysis has not been done for the distributed design. (10 refs., 3 figs., 8 tabs.)

  14. Capacitor blocks for linear transformer driver stages.

    Science.gov (United States)

    Kovalchuk, B M; Kharlov, A V; Kumpyak, E V; Smorudov, G V; Zherlitsyn, A A

    2014-01-01

    In the Linear Transformer Driver (LTD) technology, the low inductance energy storage components and switches are directly incorporated into the individual cavities (named stages) to generate a fast output voltage pulse, which is added along a vacuum coaxial line like in an inductive voltage adder. LTD stages with air insulation were recently developed, where air is used both as insulation in a primary side of the stages and as working gas in the LTD spark gap switches. A custom designed unit, referred to as a capacitor block, was developed for use as a main structural element of the transformer stages. The capacitor block incorporates two capacitors GA 35426 (40 nF, 100 kV) and multichannel multigap gas switch. Several modifications of the capacitor blocks were developed and tested on the life time and self breakdown probability. Blocks were tested both as separate units and in an assembly of capacitive module, consisting of five capacitor blocks. This paper presents detailed design of capacitor blocks, description of operation regimes, numerical simulation of electric field in the switches, and test results.

  15. Molecular simulations of MOF membranes for separation of ethane/ethene and ethane/methane mixtures† †Electronic supplementary information (ESI) available: List of the MOFs studied in this work and their structural properties. Potential parameters of gas molecules used in the simulations. See DOI: 10.1039/c7ra11562h

    Science.gov (United States)

    Altintas, Cigdem

    2017-01-01

    Metal organic framework (MOF) membranes have been widely investigated for gas separation applications. Several MOFs have been recently examined for selective separation of C2H6. Considering the large number of available MOFs, it is not possible to fabricate and test the C2H6 separation performance of every single MOF membrane using purely experimental methods. In this study, we used molecular simulations to assess the membrane-based C2H6/C2H4 and C2H6/CH4 separation performances of 175 different MOF structures. This is the largest number of MOF membranes studied to date for C2H6 separation. We computed adsorption selectivity, diffusion selectivity, membrane selectivity and gas permeability of MOFs for C2H6/C2H4 and C2H6/CH4 mixtures. Our results show that a significant number of MOF membranes are C2H6 selective for C2H6/C2H4 separation in contrast to traditional nanoporous materials. Selectivity and permeability of MOF membranes were compared with other membrane materials, such as polymers, zeolites, and carbon molecular sieves. Several MOFs were identified to exceed the upper bound established for polymeric membranes and many MOF membranes exhibited higher gas permeabilities than zeolites and carbon molecular sieves. Examining the structure–performance relations of MOF membranes revealed that MOFs with cavity diameters between 6 and 9 Å, porosities lower than 0.50, and surface areas between 500–1000 m2 g–1 have high C2H6 selectivities. The results of this study will be useful to guide the experiments to the most promising MOF membranes for efficient separation of C2H6 and to accelerate the development of new MOFs with high C2H6 selectivities. PMID:29308193

  16. A two-stage ethanol-based biodiesel production in a packed bed reactor

    DEFF Research Database (Denmark)

    Xu, Yuan; Nordblad, Mathias; Woodley, John

    2012-01-01

    were conducted in a simulated series of reactors by repeatedly passing the reaction mixture through a single reactor, with separation of the by-product glycerol and water between passes in the first and second stages, respectively. The second stage brought the major components of biodiesel to ‘in......-spec’ levels according to the European biodiesel specifications for methanol-based biodiesel. The highest overall productivity achieved in the first stage was 2.52 kg FAEE(kg catalyst)−1 h−1 at a superficial velocity of 7.6 cm min−1, close to the efficiency of a stirred tank reactor under similar conditions...

  17. Techno-environmental assessment of the green biorefinery concept: Combining process simulation and life cycle assessment at an early design stage

    DEFF Research Database (Denmark)

    Corona, Andrea; Ambye-Jensen, Morten; Vega, Giovanna Croxatto

    2018-01-01

    The Green biorefinery (GBR) is a biorefinery concept that converts fresh biomass into value-added products. The present study combines a Process Flowsheet Simulation (PFS) and Life Cycle Assessment (LCA) to evaluate the technical and environmental performance of different GBR configurations...

  18. Apparatus for diffusion separation

    International Nuclear Information System (INIS)

    Nierenberg, W.A.

    1976-01-01

    A diffuser separator apparatus is described which comprises a plurality of flow channels in a single stage. Each of said channels has an inlet port and an outlet port and a constant cross sectional area between said ports. At least a portion of the defining surface of each of said channels is a diffusion separation membrane, and each of said channels is a different cross sectional area. Means are provided for connecting said channels in series so that each successive channel of said series has a smaller cross sectional area than the previous channel of said series. Also provided are a source of gaseous mixture, individual means for flowing said gaseous mixture to the inlet port of each of said channels, gas receiving and analyzing means, individual means for flowing gas passing from each of said outlet ports and means for flowing gas passing through said membranes to said receiving and analyzing means, and individual means for connecting the outlet port of each channel with the inlet port of the channel having the next smaller cross sectional area

  19. The number of life-history stages does not influence the androgen responsiveness to male-male interactions: sedentary and migratory black redstarts (Phoenicurus ochruros) do not elevate testosterone in response to simulated territorial intrusions.

    Science.gov (United States)

    Villavicencio, C P; Blas, J; Goymann, W

    2014-09-01

    High plasma levels of testosterone at the beginning of the breeding season adjust male physiology for mating and promote territorial behavior in birds. Conversely intra-sexual competition may elicit a temporary increase in circulating testosterone. Male black redstarts (Phoenicurus ochruros) from migratory populations show the expected increase in baseline testosterone during early breeding, but circulating testosterone levels do not change in response to male-male interactions. Because sedentary populations express fewer life-history stages they may be more flexible in timing of life-history stages and more responsive to environmental modulation of hormone concentrations. Therefore, we tested whether the androgen responsiveness to male-male interactions differs between migratory (6 life-history stages) and sedentary black redstarts (3 life-history stages) during early breeding, predicting that in contrast to migratory birds, sedentary birds would modulate testosterone in response to simulated territorial intrusions (STI). In contrast to our prediction, sedentary males did not modulate post-capture testosterone levels in response to simulated territorial intrusions. Males of both populations increased testosterone after an injection of gonadotropin releasing hormone (GnRH), demonstrating that they were capable of increasing testosterone. Interestingly, in sedentary males the GnRH injection elicited a higher testosterone response in STI males than in control males. The two populations did not differ in their behavioral response to the STIs, except that sedentary males spent less time close to the decoy. In combination with previous data from black redstarts and other socially monogamous and biparental birds our current study adds to the growing evidence that current theory regarding hormone-behavior relationship needs to be refined. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Russian separation program

    International Nuclear Information System (INIS)

    Rea, J.L.

    1993-01-01

    A small contract signed in FY92 with the Khlopin Radium Institute marked the beginning of the Russian Separations program. Under this contract the Khlopin Radium Institute performed laboratory and dynamic hot-cell testing using cobalt dicarbollide technology on simulated radioactive wastes similar to those found at DOE sites in the United States. The current scope of investigation has been extended to identify prospective technologies for application to other United States needs. The Khlopin Radium Institute project served as a model for three other pilot scale technology development projects. The premise of the pilot scale projects is to enable Russian scientists to demonstrate their technology in the context of DOE needs, using Russian technical expertise has proven to be a cost-effective means of screening Russian technologies

  1. Numerical simulation of separated flows in channels

    Czech Academy of Sciences Publication Activity Database

    Louda, P.; Příhoda, Jaromír; Sváček, P.; Kozel, K.

    2012-01-01

    Roč. 21, č. 2 (2012), s. 145-153 ISSN 1003-2169 R&D Projects: GA ČR GA103/09/0977 Institutional research plan: CEZ:AV0Z20760514 Keywords : backward facing step flow * EARSM model * SST model Subject RIV: BK - Fluid Dynamics Impact factor: 0.302, year: 2012 http://www.springerlink.com/content/806t56t72787g643/fulltext.pdf

  2. Development of Radiochemical Separation Technology

    International Nuclear Information System (INIS)

    Lee, Eil Hee; Kim, K. W.; Yang, H. B.

    2007-06-01

    This project of the second phase was aimed at the development of basic unit technologies for advanced partitioning, and the application tests of pre-developed partitioning technologies for separation of actinides by using a simulated multi-component radioactive waste containing Am, Np, Tc, U and so on. The goals for recovery yield of TRU, and for purity of Tc are high than 99% and about 99%, respectively. The work scopes and contents were as follows. 1). For the development of basic unit technologies for advanced partitioning. 1. Development of technologies for co-removal of TRU and for mutual separation of U and TRU with a reduction-complexation reaction. 2. Development of extraction system for high-acidity co-separation of An(+3) and Ln(+3) and its radiolytic evaluation. 3. Synthesis of extractants for the selective separation of An(+3) and its relevant extraction system development. 4. Development of a hybrid system for the recovery of noble metals and its continuous separation tests. 5. Development of electrolytic system for the decompositions of N-NO3 and N-NH3 compounds to nitrogen gas. 2). For the application test of pre-developed partitioning technologies for the separation of actinide elements in a simulated multi-component solution equivalent to HLW level. 1. Co-separation of Tc, Np and U by a (TBP-TOA)/NDD system. 2. Mutual-separation of Am, Cm and RE elements by a (Zr-DEHPA)/NDD system. All results will be used as the fundamental data for the development of advanced partitioning process in the future

  3. Development of Radiochemical Separation Technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eil Hee; Kim, K. W.; Yang, H. B. (and others)

    2007-06-15

    This project of the second phase was aimed at the development of basic unit technologies for advanced partitioning, and the application tests of pre-developed partitioning technologies for separation of actinides by using a simulated multi-component radioactive waste containing Am, Np, Tc, U and so on. The goals for recovery yield of TRU, and for purity of Tc are high than 99% and about 99%, respectively. The work scopes and contents were as follows. 1). For the development of basic unit technologies for advanced partitioning. 1. Development of technologies for co-removal of TRU and for mutual separation of U and TRU with a reduction-complexation reaction. 2. Development of extraction system for high-acidity co-separation of An(+3) and Ln(+3) and its radiolytic evaluation. 3. Synthesis of extractants for the selective separation of An(+3) and its relevant extraction system development. 4. Development of a hybrid system for the recovery of noble metals and its continuous separation tests. 5. Development of electrolytic system for the decompositions of N-NO3 and N-NH3 compounds to nitrogen gas. 2). For the application test of pre-developed partitioning technologies for the separation of actinide elements in a simulated multi-component solution equivalent to HLW level. 1. Co-separation of Tc, Np and U by a (TBP-TOA)/NDD system. 2. Mutual-separation of Am, Cm and RE elements by a (Zr-DEHPA)/NDD system. All results will be used as the fundamental data for the development of advanced partitioning process in the future.

  4. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and li......, the book asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities?...... that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments...

  5. Staged membrane oxidation reactor system

    Science.gov (United States)

    Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

    2012-09-11

    Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

  6. Hydroquinone solubility and separation processes

    OpenAIRE

    Maria Eugénia Macedo; Fátima L. Mota; António Queimada

    2011-01-01

    In chemical process design, separation unitsare usually veryimportant for the purification of one or more components from thereaction stage. This step may involve different fluid or solid phases.Chemical engineering thermodynamics is the area of chemicalengineering that studies the distribution of such components amongequilibrium phases given temperature, pressure and feed composition.Therefore, reliable and accurate data on phase equilibria are crucial tooptimize and scale up process separat...

  7. Simulation of main steam and feedwater system of full scope simulator for Qinshan 300 MW Nuclear Power Unit

    International Nuclear Information System (INIS)

    Zhao Xiaoyu

    1996-01-01

    The simulation of main steam and feedwater system is the most important and maximal part in secondary circuit model, including all of main steam and feedwater's thermal-hydraulic properties, except heat-exchange of secondary side of steam generator. It simulates main steam header, steam power in each stage of turbine, moisture separator-reheater, deaerator, condenser, high pressure and low pressure heater, auxiliary feedwater and main steam bypass in full scope

  8. Development of a model for unsteady deterministic stresses adapted to the multi-stages turbomachines simulation; Developpement d'un modele de tensions deterministes instationnaires adapte a la simulation de turbomachines multi-etagees

    Energy Technology Data Exchange (ETDEWEB)

    Charbonnier, D.

    2004-12-15

    The physical phenomena observed in turbomachines are generally three-dimensional and unsteady. A recent study revealed that a three-dimensional steady simulation can reproduce the time-averaged unsteady phenomena, since the steady flow field equations integrate deterministic stresses. The objective of this work is thus to develop an unsteady deterministic stresses model. The analogy with turbulence makes it possible to write transport equations for these stresses. The equations are implemented in steady flow solver and e model for the energy deterministic fluxes is also developed and implemented. Finally, this work shows that a three-dimensional steady simulation, by taking into account unsteady effects with transport equations of deterministic stresses, increases the computing time by only approximately 30 %, which remains very interesting compared to an unsteady simulation. (author)

  9. Separation Anxiety (For Parents)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Separation Anxiety KidsHealth / For Parents / Separation Anxiety What's in this ... both of you get through it. About Separation Anxiety Babies adapt pretty well to other caregivers. Parents ...

  10. Isotope separation method and apparatus

    International Nuclear Information System (INIS)

    Lyon, R.K.; Eisner, P.N.; Thomas, W.R.L.

    1980-01-01

    A method and apparatus are specified for separating a mixture of isotopes present in a compound, preferably a gaseous compound, into two or more parts in each of which the abundances of the isotopes differ from the natural abundances of the isotopes in the compound. The invention particularly relates to carrying out a laser induced, isotopically selective conversion of gaseous molecules in such a manner as to achieve more than one stage of isotope separation along the length of the laser beam. As an example, the invention is applied to the separation of the isotopes of uranium in UF 6 , in which either the U-235 or U-238 isotope is selectively excited by means of irradiation from an infrared laser, and the selectively excited isotope converted into a product that can be recovered from UF 6 by one of a variety of methods that are described. (U.K.)

  11. Fictional Separation Logic

    DEFF Research Database (Denmark)

    Jensen, Jonas Buhrkal; Birkedal, Lars

    2012-01-01

    , separation means physical separation. In this paper, we introduce \\emph{fictional separation logic}, which includes more general forms of fictional separating conjunctions P * Q, where "*" does not require physical separation, but may also be used in situations where the memory resources described by P and Q...... overlap. We demonstrate, via a range of examples, how fictional separation logic can be used to reason locally and modularly about mutable abstract data types, possibly implemented using sophisticated sharing. Fictional separation logic is defined on top of standard separation logic, and both the meta...

  12. Ion mass separation modeling inside a plasma separator

    Science.gov (United States)

    Gavrikov, A. V.; Sidorov, V. S.; Smirnov, V. P.; Tarakanov, V. P.

    2018-01-01

    The results have been obtained in a continuation of the work for ion trajectories calculation in crossed electric and magnetic fields and also in a close alignment with the plasma separation study development. The main task was to calculate trajectories of ions of the substance imitating spent nuclear fuel in order to find a feasible plasma separator configuration. The three-dimensional modeling has been made with KARAT code in a single-particle approximation. The calculations have been performed under the following conditions. Magnetic field is produced by 2 coils of wire, the characteristic field strength in a uniform area is 1.4 kG. Electric field is produced by several electrodes (axial ones, anode shell and capacitor sheets) with electric potential up to 500 V. The characteristic linear size of the cylindrical separator area is ∼ 100 cm. The characteristic size of injection region is ∼ 1 cm. Spatial position of the injection region is inside the separator. The injection direction is along magnetic lines. Injected particles are single-charged ions with energies from 0 to 20 eV with atomic masses A = 150 and 240. Wide spreading angle range was investigated. As a result of simulation a feasible separator configuration was found. This configuration allows to achieve more than 10 cm spatial division distance for the separated ions and is fully compliant with and supplementary to the vacuum arc-based ion source research.

  13. The Utility of the Swine Model to Assess Biological Rhythms and Their Characteristics during Different Stages of Residence in a Simulated Intensive Care Unit: A Pilot Study.

    Science.gov (United States)

    Leyden, Katrina N; Hanneman, Sandra K; Padhye, Nikhil S; Smolensky, Michael H; Kang, Duck-Hee; Chow, Diana Shu-Lian

    2015-01-01

    The purpose of this pilot study was to explore the utility of the mammalian swine model under simulated intensive care unit (sICU) conditions and mechanical ventilation (MV) for assessment of the trajectory of circadian rhythms of sedation requirement, core body temperature (CBT), pulmonary mechanics (PM) and gas exchange (GE). Data were collected prospectively with an observational time-series design to describe and compare circadian rhythms of selected study variables in four swine mechanically ventilated for up to seven consecutive days. We derived the circadian (total variance explained by rhythms of τ between 20 and 28 h)/ultradian (total variance explained by rhythms of τ between 1 and rhythms, and compare findings between the early (first 3 days) and late (subsequent days) sICU stay. All pigs exhibited statistically significant circadian rhythms (τ between 20 and 28 h) in CBT, respiratory rate and peripheral oxygen saturation, but circadian rhythms were detected less frequently for sedation requirement, spontaneous minute volume, arterial oxygen tension, arterial carbon dioxide tension and arterial pH. Sedation did not appear to mask the circadian rhythms of CBT, PM and GE. Individual subject observations were more informative than group data, and provided preliminary evidence that (a) circadian rhythms of multiple variables are lost or desynchronized in mechanically ventilated subjects, (b) robustness of circadian rhythm varies with subject morbidity and (c) healthier pigs develop more robust circadian rhythm profiles over time in the sICU. Comparison of biological rhythm profiles among sICU subjects with similar severity of illness is needed to determine if the results of this pilot study are reproducible. Identification of consistent patterns may provide insight into subject morbidity and timing of such therapeutic interventions as weaning from MV.

  14. Understanding Coastal Wetland Vulnerability to Sea-Level Rise Enhanced Inundation Using Real-Time Stage Monitoring, LiDAR, and Monte Carlo Simulation in Everglades National Park

    Science.gov (United States)

    Cooper, H.; Zhang, C.

    2017-12-01

    Coastal wetlands are one of the most productive ecological systems in the world, providing critical habitat area and valuable ecosystem services such as carbon sequestration. However, due to their location in low lying areas, coastal wetlands are particularly vulnerable to sea-level rise (SLR). Everglades National Park (ENP) encompasses the southern-most portion of the Greater Everglades Ecosystem, and is the largest subtropical wetland in the USA. Water depths have shown to have a significant relationship to vegetation community composition and organization while also playing a crucial role in vegetation health throughout the Everglades. Live plants play a vital role in maintaining soil structure (i.e. elevation), and decreases in vegetation health can cause peat collapse or wetland loss resulting in dramatic habitat, organic soil, and elevation loss posing concerns for Everglades management and restoration. One suspected mechanism for peat collapse is enhanced inundation due to SLR, thus mapping and modeling water depths is a critical component to understanding the potential impacts of future SLR. Previous research in the Everglades focused on a conventional Water Depth Model (WDM) approach where a Digital Elevation Model (DEM) is subtracted from a Water Table Elevation Model (WTEM). In this study, the conventional WDM approach is extended to a more rigorous WDM technique so that the accuracy and precision of the underlying data may be considered. Monte Carlo simulation is used to propagate probability distributions through our SLR depth model using our Random Forest-based LiDAR DEM, Empirical Bayesian Kriging-based WTEMs, uncertainties in vertical datums, soil accretion projections, and regional sea-level rise projections. Water depth maps were produced for the wet and dry seasons in April and October, which successfully revealed the potential spatial and temporal water depth variations due to future SLR. It is concluded that a more rigorous WDM technique helps

  15. Enhanced separation of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Lyon, K. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Greenhalgh, M. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Herbst, R. S. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Garn, T. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Welty, A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Soderstrom, M. D. [Cytec Solvay Group, Tempe, AZ (United States); Jakovljevic, B. [Cytec Solvay Group, Niagara Falls, ON (Canada)

    2016-09-01

    Industrial rare earth separation processes utilize PC88A, a phosphonic acid ligand, for solvent extraction separations. The separation factors of the individual rare earths, the equipment requirements, and chemical usage for these flowsheets are well characterized. Alternative ligands such as Cyanex® 572 and the associated flowsheets are being investigated at the pilot scale level to determine if significant improvements to the current separation processes can be realized. These improvements are identified as higher separation factors, reduced stage requirements, or reduced chemical consumption. Any of these improvements can significantly affect the costs associated with these challenging separation proccesses. A mid/heavy rare earth element (REE) separations flowsheet was developed and tested for each ligand in a 30 stage mixer-settler circuit to compare the separation performance of PC88A and Cyanex® 572. The ligand-metal complex strength of Cyanex® 572 provides efficient extraction of REE while significantly reducing the strip acid requirements. Reductions in chemical consumption have a significant impact on process economics for REE separations. Partitioning results summarized Table 1 indicate that Cyanex® 572 offers the same separation performance as PC88A while reducing acid consumption by 30% in the strip section for the mid/heavy REE separation. Flowsheet Effluent Compositions PC88A Cyanex® 572 Raffinate Mid REE Heavy REE 99.40% 0.60% 99.40% 0.60% Rich Mid REE Heavy REE 2.20% 97.80% 0.80% 99.20% Liquor Strip Acid Required 3.4 M 2.3 M Table 1 – Flowsheet results comparing separation performance of PC88A and Cyanex® 572 for a mid/heavy REE separation.

  16. Fundamental laws of separation by the gaseous diffusion process

    International Nuclear Information System (INIS)

    Bouligand, G.M.

    1964-01-01

    Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [fr

  17. Separation anxiety in children

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/001542.htm Separation anxiety in children To use the sharing features on this page, ... to test their independence. To get over separation anxiety, children need to: Feel safe in their home. Trust ...

  18. Magnetic separation of algae

    Science.gov (United States)

    Nath, Pulak; Twary, Scott N.

    2016-04-26

    Described herein are methods and systems for harvesting, collecting, separating and/or dewatering algae using iron based salts combined with a magnetic field gradient to separate algae from an aqueous solution.

  19. Separators for electrochemical cells

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2018-01-16

    Provided are separators for use in an electrochemical cell comprising (a) an inorganic oxide and (b) an organic polymer, wherein the inorganic oxide comprises organic substituents. Also provided are electrochemical cells comprising such separators.

  20. Combined cycle simulator with gas turbine and steam turbine with one vaporization stage; Simulador de ciclo combinado con turbina de gas y de vapor con un nivel de vaporizacion

    Energy Technology Data Exchange (ETDEWEB)

    Del Valle Cardenas, B.; Lugo Leyte, R. [Universidad Autonoma Metropolitana, Depto de Ingenieria de Procesos e Hidraulica, Mexico, D. F. (Mexico); Toledo Velazquez, Miguel; Tolentino Eslava, G. [Seccion de Estudios de Posgrado e Investigacion, Laboratorio de Ingenieria Termica e Hidraulica Aplicada, ESIME-IPN-COFFA, Mexico, D. F. (Mexico)

    1998-12-31

    This paper shows the thermal analysis of a combined cycle with gas and steam turbines with one vaporization stage. The analysis is performed through a computer program, which allows the simulation of cycles with different operational conditions, obtaining this way a series of results that permits to know the way these cycles behave in effecting temperature and pressure changes; besides of being an excellent tool in thermodynamics for the user. The simulators were performed in Borland C++ and Builder C++ Versions 4.5 and 2.0 respectively, creating in this way a friendly ambient for the user. This tool offers the opportunity to all its users the ability to simulate combined cycles in a fast and easy way in order to obtain a wider understanding of its thermodynamic behavior. [Espanol] En el presente trabajo se muestra el analisis termico de un ciclo combinado con turbinas de gas y de vapor con un nivel de vaporizacion. El analisis se realiza a traves de un programa de computo, el cual permite simular los ciclos con diferentes condiciones de operacion, obteniendo con esto una serie de resultados que permiten conocer la forma en que trabajan estos ciclos al realizar cambios en temperaturas y presiones; ademas de que es una excelente herramienta para el usuario en termodinamica. Los simuladores fueron realizados en Borland C++ y Builder C++ Versiones 4.5 y 2.0 respectivamente, creandose asi un ambiente amigable para el usuario. Esta herramienta brinda la oportunidad a todos los usuarios de poder simular ciclos combinados de una manera rapida y sencilla con el fin de obtener una comprension mas amplia de su comportamiento termodinamico.

  1. Chromatographic separations of stereoisomers

    Energy Technology Data Exchange (ETDEWEB)

    Souter, R.W.

    1985-01-01

    This text covers both diastereomers and enantiomers; describes techniques for GC, HPLC, and other chromatographic methods; and tabulates results of various applications by both techniques and compound class. It provides current knowledge about separation mechanisms and interactions of asymmetric molecules, as well as experimental and commercial materials such as columns, instruments, and derivatization reagents. The contents also include stereoisomer separations by gas chromatography. Stereoisomer separations by high-performance liquid chromatography. Stereoisomer separations by other chromatographic techniques.

  2. Meniscus Membranes For Separation

    Science.gov (United States)

    Dye, Robert C.; Jorgensen, Betty; Pesiri, David R.

    2005-09-20

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  3. Meniscus membranes for separations

    Science.gov (United States)

    Dye, Robert C [Irvine, CA; Jorgensen, Betty [Jemez Springs, NM; Pesiri, David R [Aliso Viejo, CA

    2004-01-27

    Gas separation membranes, especially meniscus-shaped membranes for gas separations are disclosed together with the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream. In addition, a rapid screening system for simultaneously screening polymer materials for effectiveness in gas separation is provided.

  4. Using spatiotemporal source separation to identify prominent features in multichannel data without sinusoidal filters.

    Science.gov (United States)

    Cohen, Michael X

    2017-09-27

    The number of simultaneously recorded electrodes in neuroscience is steadily increasing, providing new opportunities for understanding brain function, but also new challenges for appropriately dealing with the increase in dimensionality. Multivariate source separation analysis methods have been particularly effective at improving signal-to-noise ratio while reducing the dimensionality of the data and are widely used for cleaning, classifying and source-localizing multichannel neural time series data. Most source separation methods produce a spatial component (that is, a weighted combination of channels to produce one time series); here, this is extended to apply source separation to a time series, with the idea of obtaining a weighted combination of successive time points, such that the weights are optimized to satisfy some criteria. This is achieved via a two-stage source separation procedure, in which an optimal spatial filter is first constructed and then its optimal temporal basis function is computed. This second stage is achieved with a time-delay-embedding matrix, in which additional rows of a matrix are created from time-delayed versions of existing rows. The optimal spatial and temporal weights can be obtained by solving a generalized eigendecomposition of covariance matrices. The method is demonstrated in simulated data and in an empirical electroencephalogram study on theta-band activity during response conflict. Spatiotemporal source separation has several advantages, including defining empirical filters without the need to apply sinusoidal narrowband filters. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  5. Safety shutdown separators

    Science.gov (United States)

    Carlson, Steven Allen; Anakor, Ifenna Kingsley; Farrell, Greg Robert

    2015-06-30

    The present invention pertains to electrochemical cells which comprise (a) an anode; (b) a cathode; (c) a solid porous separator, such as a polyolefin, xerogel, or inorganic oxide separator; and (d) a nonaqueous electrolyte, wherein the separator comprises a porous membrane having a microporous coating comprising polymer particles which have not coalesced to form a continuous film. This microporous coating on the separator acts as a safety shutdown layer that rapidly increases the internal resistivity and shuts the cell down upon heating to an elevated temperature, such as 110.degree. C. Also provided are methods for increasing the safety of an electrochemical cell by utilizing such separators with a safety shutdown layer.

  6. Acoustofluidic bacteria separation

    International Nuclear Information System (INIS)

    Li, Sixing; Huang, Tony Jun; Ma, Fen; Zeng, Xiangqun; Bachman, Hunter; Cameron, Craig E

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device. (paper)

  7. Rapid chemical separations

    CERN Document Server

    Trautmann, N

    1976-01-01

    A survey is given on the progress of fast chemical separation procedures during the last few years. Fast, discontinuous separation techniques are illustrated by a procedure for niobium. The use of such techniques for the chemical characterization of the heaviest known elements is described. Other rapid separation methods from aqueous solutions are summarized. The application of the high speed liquid chromatography to the separation of chemically similar elements is outlined. The use of the gas jet recoil transport method for nuclear reaction products and its combination with a continuous solvent extraction technique and with a thermochromatographic separation is presented. Different separation methods in the gas phase are briefly discussed and the attachment of a thermochromatographic technique to an on-line mass separator is shown. (45 refs).

  8. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  9. Uranium enrichment by the separation nozzle process

    International Nuclear Information System (INIS)

    Becker, E.W.; Bier, W.; Ehrfeld, W.; Schubert, K.; Schuette, R.; Seidel, D.

    1975-11-01

    The separation nozzle process for the enrichment of the light uranium isotope U-235 has been developed at the Karlsruhe Nuclear Research Center as an alternative to the gaseous diffusion and centrifuge processes. Since 1970 the STEAG company, Essen, has been involved in the commercial implementation of the nozzle process. A first separation nozzle process. A first separation nozzle demonstration plant with a separative capacity of 180 t SWU/a shall be erected in Brazil with the participation of the Brazilian company NUCLEBRAS and the German companies STEAG and INTERATOM. Methods for the mass production of separation elements were developed by industry and extensive performance tests were carried out on commercially fabricated separation elements. Two prototype separative stages were successfully tested in Karlsruhe. Besides further plant components, a prototype of a UF 6 recycle facility was developed which serves the purpose of stripping the UF 6 from the light auxiliary gas to be recycled in a separation nozzle cascade. The performance level achieved to date characterizes the separation nozzle process as reliable and feasible economically. Therefore, the erection of a separation nozzle demonstration plant can be recognized as the implementation of an enrichment process which combines a reliable and comparatively simple technology with a high potential for further improvements. (orig.) [de

  10. Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting.

    Science.gov (United States)

    Gido, Ben; Friedler, Eran; Broday, David M

    2016-08-02

    An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5-65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior.

  11. Radioactive rare gas separation using a separation cell with two kinds of membrane differing in gas permeability tendency

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Ozaki, Osamu; Sato, Hajime; Kimura, Shoji; Miyauchi, Terukatsu.

    1977-01-01

    A separation cell embodying two kinds of membrane-porous and nonporous, i.e. differing in gas permeability - has a separation factor higher than possible with a conventional separation cell with a single kind of membrane. The performance of such separation cells and of cascades constituted thereof are analyzed theoretically and measured experimentally for different conditions of operation, to determine the applicability of the concept to the separation of rare gases from gaseous waste out of nuclear plants. Theoretical considerations indicate that, in a cascade composed of symmetric separation cells, the separation performance can be improved by recycling part of the effluent from a cell back through the same cell (recycling cascade). It is shown that its performance is better than with the arrangement of diverting another effluent several stages upstream. With the recycling cascade, the symmetric separation recycling rate is determined by the depletion separation and enrichment separation factors relevant to the respective membranes. The separation performance of a 9-stage recycling cascade composed of separation cells with silicone rubber tubular membranes and cellulose acetate tubular membranes is derived for a case of Kr separation from N 2 -Kr mixture. The experimental data coincide well with the analytical results. From both the experimental and the analytical results, it is found that the attainable separation coefficient per stage of the cascade comes to average approximately 0.97. (auth.)

  12. Feasibility study of iron mineral separation from red mud by high gradient superconducting magnetic separation

    Science.gov (United States)

    Li, Yiran; Wang, Jun; Wang, Xiaojun; Wang, Baoqiang; Luan, Zhaokun

    2011-02-01

    The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (separation stages when RM 1# and RM 2# were fed respectively. The mass recovery of iron concentrates was about 10% after once separation process regardless of RM 1# or RM 2# was fed. Extreme fine particles (separation from RM by HGSMS. Some improvement should be studied to enhance the efficiency of iron separation. It is possible for HGSMS to separate RM into high iron content part and low iron content part, the former part could be used in iron-making furnace and the later part could be recycling to sintering process for alumina production or used as construction material.

  13. Development of a system based in a digital signal processor (DSP) for a simulator of power regulation in a reactor: first stage; Desarrollo de un sistema basado en un DSP para un simulador de regulacion de potencia en un reactor: 1. etapa

    Energy Technology Data Exchange (ETDEWEB)

    Benitez R, J.S.; Perez C, B. [Instituto Nacional de Investigaciones Nucleares, Km. 36.5 Carretera Mexico-Toluca, Municipio de Ocoyoacac, 52045 Estado de Mexico (Mexico)

    2002-07-01

    The first stage of the development of a digital system based on a DSP is presented which forms part of an hybrid simulator for the power regulation in am model of the punctual kinetics of a TRIGA reactor type. The DSP performs the regulation, using a Mandami type algorithm of diffuse control. In the algorithm, the universe of the output variable is discretized for performing in an unique stage the aggregation functions and dis-diffusization. (Author)

  14. Attainability and minimum energy of multiple-stage cascade membrane Systems

    KAUST Repository

    Alshehri, Ali

    2015-08-12

    Process design and simulation of multi-stage membrane systems have been widely studied in many gas separation systems. However, general guidelines have not been developed yet for the attainability and the minimum energy consumption of a multi-stage membrane system. Such information is important for conceptual process design and thus it is the topic of this work. Using a well-mixed membrane model, it was determined that the attainability curve of multi-stage systems is defined by the pressure ratio and membrane selectivity. Using the constant recycle ratio scheme, the recycle ratio can shift the attainability behavior between single-stage and multi-stage membrane systems. When the recycle ratio is zero, all of the multi-stage membrane processes will decay to a single-stage membrane process. When the recycle ratio approaches infinity, the required selectivity and pressure ratio reach their absolute minimum values, which have a simple relationship with that of a single-stage membrane process, as follows: View the MathML sourceSn=S1, View the MathML sourceγn=γ1, where n is the number of stages. The minimum energy consumption of a multi-stage membrane process is primarily determined by the membrane selectivity and recycle ratio. A low recycle ratio can significantly reduce the required membrane selectivity without substantial energy penalty. The energy envelope curve can provide a guideline from an energy perspective to determine the minimum required membrane selectivity in membrane process designs to compete with conventional separation processes, such as distillation.

  15. Understanding cancer staging

    Science.gov (United States)

    ... detailed information about the cancer stage. TNM Staging System The most common system for staging cancer in the form of solid tumor is the TNM system. Most providers and cancer centers use it to stage ...

  16. Chaotic attractors with separated scrolls

    International Nuclear Information System (INIS)

    Bouallegue, Kais

    2015-01-01

    This paper proposes a new behavior of chaotic attractors with separated scrolls while combining Julia's process with Chua's attractor and Lorenz's attractor. The main motivation of this work is the ability to generate a set of separated scrolls with different behaviors, which in turn allows us to choose one or many scrolls combined with modulation (amplitude and frequency) for secure communication or synchronization. This set seems a new class of hyperchaos because each element of this set looks like a simple chaotic attractor with one positive Lyapunov exponent, so the cardinal of this set is greater than one. This new approach could be used to generate more general higher-dimensional hyperchaotic attractor for more potential application. Numerical simulations are given to show the effectiveness of the proposed theoretical results

  17. MODELING OF HIGH STORAGE SHEET DEPOT WITH PLANT SIMULATION

    Directory of Open Access Journals (Sweden)

    Andrzej Jardzioch

    2013-03-01

    Full Text Available Manufacturing processes are becoming increasingly automated. Introduction of innovative solutions often necessitate processing very large number of signals from various devices. Correctness tests of the components configuration becomes a compiled operation requiring vast expenditure of time and knowledge. The models may be a mathematical reflection of the actual object. Many actions can be computer-assisted to varying degree. One example is construction of simulation models. These can also be simulation models developed in advanced software. The stages of creating a model may be purely random. This paper aims at a closer analysis of the simulation model based on the high storage sheet depot modeling using Plant Simulation software. The results of analysis can be used for optimization, but this stage is a separate issue.

  18. Pilot and Controller Evaluations of Separation Function Allocation in Air Traffic Management

    Science.gov (United States)

    Wing, David; Prevot, Thomas; Morey, Susan; Lewis, Timothy; Martin, Lynne; Johnson, Sally; Cabrall, Christopher; Como, Sean; Homola, Jeffrey; Sheth-Chandra, Manasi; hide

    2013-01-01

    Two human-in-the-loop simulation experiments were conducted in coordinated fashion to investigate the allocation of separation assurance functions between ground and air and between humans and automation. The experiments modeled a mixed-operations concept in which aircraft receiving ground-based separation services shared the airspace with aircraft providing their own separation service (i.e., self-separation). Ground-based separation was provided by air traffic controllers without automation tools, with tools, or by ground-based automation with controllers in a managing role. Airborne self-separation was provided by airline pilots using self-separation automation enabled by airborne surveillance technology. The two experiments, one pilot-focused and the other controller-focused, addressed selected key issues of mixed operations, assuming the starting point of current-day operations and modeling an emergence of NextGen technologies and procedures. In the controller-focused experiment, the impact of mixed operations on controller performance was assessed at four stages of NextGen implementation. In the pilot-focused experiment, the limits to which pilots with automation tools could take full responsibility for separation from ground-controlled aircraft were tested. Results indicate that the presence of self-separating aircraft had little impact on the controllers' ability to provide separation services for ground-controlled aircraft. Overall performance was best in the most automated environment in which all aircraft were data communications equipped, ground-based separation was highly automated, and self-separating aircraft had access to trajectory intent information for all aircraft. In this environment, safe, efficient, and highly acceptable operations could be achieved for twice today's peak airspace throughput. In less automated environments, reduced trajectory intent exchange and manual air traffic control limited the safely achievable airspace throughput and

  19. Separation of flow

    CERN Document Server

    Chang, Paul K

    2014-01-01

    Interdisciplinary and Advanced Topics in Science and Engineering, Volume 3: Separation of Flow presents the problem of the separation of fluid flow. This book provides information covering the fields of basic physical processes, analyses, and experiments concerning flow separation.Organized into 12 chapters, this volume begins with an overview of the flow separation on the body surface as discusses in various classical examples. This text then examines the analytical and experimental results of the laminar boundary layer of steady, two-dimensional flows in the subsonic speed range. Other chapt

  20. Centrifugal gas separator

    International Nuclear Information System (INIS)

    Sakurai, Mitsuo.

    1970-01-01

    A centrifugal gas separator of a highly endurable construction and with improved gas sealing qualities utilizes a cylincrical elastic bellows or similar system in cooperation with a system of dynamic pressure operable gas seals as means for removing separated gases from the interior of the rotor drum, collecting the separated gases in their respective separated gas chambers defined by the corresponding bellows and their supporting stationary wall members, gas seals and rotor end caps, and means for discharging to the exterior of the surrounding cylindrical wall member the gaseous components from their respective separated gas chambers. In the vicinity of the rotary drum motor is a mixed gas chamber and means for providing the gas mixture along a co-axial passage into the rotary drum chamber. Orifices are bored into the end caps of the rotary drum to direct the separated gases into the aforementioned separated gas chambers which, through the action of the gas seals, freely slide upon the rotating drum to collect and thereafter discharge the thus separated gases. Therefore, according to the present invention, helium gas used to prevent separated gas remixture is unnecessary and, furthermore, the gas seals and elastic bellows means provide an air-tight seal superior to that of the contact sealing system of the former art. (K.J. Owens)

  1. Gas separation performance of tapered cascade with membrane

    International Nuclear Information System (INIS)

    Ohno, Masayoshi; Morisue, Tetsuo; Ozaki, Osamu; Miyauchi, Terukatsu.

    1978-01-01

    Membrane gas separation cascades are analyzed at steady state. The method of calculating the flow rate and concentration profiles in the cascade are examined, using formulas expressing the various membrane separation cell characteristics. The method adopted is applicable to relatively high concentrations and separation factors. Considerations are further given on the steady state performance of four theoretical forms of cascade: (a) with common value of cut for all stages, (b) with symmetric separation cells, (c) with no mixing at the junction at each stage, and (d) ideal cascade. The analysis showed that, with membrane cells, the ideal cascade would have a pressure ratio varying from stage to stage. The symmetric separation cascade would provide a separation performance lower than the ideal cascade on account of the mixing at the junctions of streams possessing different concentrations, whereas the cut and separation factor of the no-mixing cascade requiring minimum membrane area exhibits zig-zag curves when plotted against stage number. Both these circumstances contribute to the lower separation performance obtained with these two forms as compared with the ideal cascade, and results in larger total membrane area; but these semi-ideal forms retain the advantage of easy practical treatment with their pressure ratio common to all stages. (auth.)

  2. Separation of hydrogen isotopes via single column pressure swing adsorption

    International Nuclear Information System (INIS)

    Wong, Y.W.; Hill, F.B.

    1981-01-01

    Separation of hydrogen isotopes based on kinetic isotope effects was studied. The mixture separated was hydrogen containing a trace of tritium as HT and the hydride was vanadium monohydride. The separation was achieved using the single-column pressure swing process. Stage separation factors are larger and product cuts smaller than for a two-column pressure swing process operated in the same monohydride phase

  3. A two-stage enzymatic ethanol-based biodiesel production in a packed bed reactor.

    Science.gov (United States)

    Xu, Yuan; Nordblad, Mathias; Woodley, John M

    2012-12-31

    A two-stage enzymatic process for producing fatty acid ethyl ester (FAEE) in a packed bed reactor is reported. The process uses an experimental immobilized lipase (NS 88001) and Novozym 435 to catalyze transesterification (first stage) and esterification (second stage), respectively. Both stages were conducted in a simulated series of reactors by repeatedly passing the reaction mixture through a single reactor, with separation of the by-product glycerol and water between passes in the first and second stages, respectively. The second stage brought the major components of biodiesel to 'in-spec' levels according to the European biodiesel specifications for methanol-based biodiesel. The highest overall productivity achieved in the first stage was 2.52 kg FAEE(kg catalyst)⁻¹ h⁻¹ at a superficial velocity of 7.6 cm min⁻¹, close to the efficiency of a stirred tank reactor under similar conditions. The overall productivity of the proposed two-stage process was 1.56 kg FAEE(kg catalyst)⁻¹ h⁻¹. Based on this process model, the challenges of scale-up have been addressed and potential continuous process options have been proposed. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Cluster evolution during the early stages of heating explosives and its relationship to sensitivity: a comparative study of TATB, β-HMX and PETN by molecular reactive force field simulations.

    Science.gov (United States)

    Wen, Yushi; Zhang, Chaoyang; Xue, Xianggui; Long, Xinping

    2015-05-14

    Clustering is experimentally and theoretically verified during the complicated processes involved in heating high explosives, and has been thought to influence their detonation properties. However, a detailed description of the clustering that occurs has not been fully elucidated. We used molecular dynamic simulations with an improved reactive force field, ReaxFF_lg, to carry out a comparative study of cluster evolution during the early stages of heating for three representative explosives: 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), β-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and pentaerythritol tetranitrate (PETN). These representatives vary greatly in their oxygen balance (OB), molecular structure, stability and experimental sensitivity. We found that when heated, TATB, HMX and PETN differ in the size, amount, proportion and lifetime of their clusters. We also found that the clustering tendency of explosives decreases as their OB becomes less negative. We propose that the relationship between OB and clustering can be attributed to the role of clustering in detonation. That is, clusters can form more readily in a high explosive with a more negative OB, which retard its energy release, secondary decomposition, further decomposition to final small molecule products and widen its detonation reaction zone. Moreover, we found that the carbon content of the clusters increases during clustering, in accordance with the observed soot, which is mainly composed of carbon as the final product of detonation or deflagration.

  5. Fundamental laws of separation by the gaseous diffusion process; Lois de separation elementaires en diffusion gazeuse

    Energy Technology Data Exchange (ETDEWEB)

    Bouligand, G.M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-07-01

    Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [French] A partir de la loi de Knudsen exprimant les debits elementaires des constituants d'un melange gazeux a travers une membrane poreuse on determine les lois et la puissance de separation de differents modeles de diffuseurs definie par leurs configurations et la nature des ecoulements gazeux. Four simplifier il n'a pas ete tenu compte des divers phenomenes physiques inherents a la diffusion et qui reduisent generalement le facteur de separation. Ces calculs font prevoir les avantages des diffuseurs du type contrecourant a trois ouvertures et peuvent servir de guide dans une theorie plus complete de la separation. (auteur)

  6. Separation of ionic solutes

    International Nuclear Information System (INIS)

    1986-01-01

    The conference proceedings contain 44 papers of which 19 were incorporated in INIS. The subject of these is the use of solvent extraction or emulsion membrane extraction for separation of fission products, rare earth compounds and actinide compunds; the sorption of radionuclides; and the use of adsorbents and chelating agents in separation processes. (J.P.)

  7. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.

    1979-01-01

    A method is described for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption after which more of the excited molecules than nonexcited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium

  8. Separation anxiety disorder

    NARCIS (Netherlands)

    Nauta, M.H.; Emmelkamp, P.M.G.; Sturmey, P.; Hersen, M.

    2012-01-01

    Separation anxiety disorder (SAD) is the only anxiety disorder that is specific to childhood; however, SAD has hardly ever been addressed as a separate disorder in clinical trials investigating treatment outcome. So far, only parent training has been developed specifically for SAD. This particular

  9. THE SEPARATION GAME

    OpenAIRE

    TRISTAN CAZENAVE

    2006-01-01

    The separation game is different from the connection game, but has some similarities. In the game of Go, it is often useful because it helps to enclose groups and areas. An evaluation function, moves generation functions and a search algorithm for the separation game are described in this paper.

  10. Space Launch System Booster Separation Aerodynamic Database Development and Uncertainty Quantification

    Science.gov (United States)

    Chan, David T.; Pinier, Jeremy T.; Wilcox, Floyd J., Jr.; Dalle, Derek J.; Rogers, Stuart E.; Gomez, Reynaldo J.

    2016-01-01

    The development of the aerodynamic database for the Space Launch System (SLS) booster separation environment has presented many challenges because of the complex physics of the ow around three independent bodies due to proximity e ects and jet inter- actions from the booster separation motors and the core stage engines. This aerodynamic environment is dicult to simulate in a wind tunnel experiment and also dicult to simu- late with computational uid dynamics. The database is further complicated by the high dimensionality of the independent variable space, which includes the orientation of the core stage, the relative positions and orientations of the solid rocket boosters, and the thrust lev- els of the various engines. Moreover, the clearance between the core stage and the boosters during the separation event is sensitive to the aerodynamic uncertainties of the database. This paper will present the development process for Version 3 of the SLS booster separa- tion aerodynamic database and the statistics-based uncertainty quanti cation process for the database.

  11. Stage-specific predictive models for breast cancer survivability.

    Science.gov (United States)

    Kate, Rohit J; Nadig, Ramya

    2017-01-01

    Survivability rates vary widely among various stages of breast cancer. Although machine learning models built in past to predict breast cancer survivability were given stage as one of the features, they were not trained or evaluated separately for each stage. To investigate whether there are differences in performance of machine learning models trained and evaluated across different stages for predicting breast cancer survivability. Using three different machine learning methods we built models to predict breast cancer survivability separately for each stage and compared them with the traditional joint models built for all the stages. We also evaluated the models separately for each stage and together for all the stages. Our results show that the most suitable model to predict survivability for a specific stage is the model trained for that particular stage. In our experiments, using additional examples of other stages during training did not help, in fact, it made it worse in some cases. The most important features for predicting survivability were also found to be different for different stages. By evaluating the models separately on different stages we found that the performance widely varied across them. We also demonstrate that evaluating predictive models for survivability on all the stages together, as was done in the past, is misleading because it overestimates performance. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  12. Fundamental Study on the Separation of Methane Isotopomer by Cryogenic Distillation

    Energy Technology Data Exchange (ETDEWEB)

    Song, K.M.; Lee, S.K.; Kim, K.S.; Kim, W.S. [Korea Electric Power Research Institute, Taejon (Korea)

    2002-07-01

    For the purpose of {sup 13}CH{sub 4} production from LNG, the state art of the application of C-13 and the marketing research were investigated. The theoretical number of stages and the number of distillation column required for the separation of {sup 13}CH{sub 4} from {sup 12}CH{sub 4}/{sup 13}CH{sub 4} mixture containing 1%-{sup 13}CH{sub 4} are calculated. Assuming the ideal liquid mixture of {sup 12}CH{sub 4} and {sup 13}CH{sub 4}, the theoretical number of stages are calculated the minimum theorical number of stages are calculated by Smoker equation and FUG method. Using the correlation between the minimum theoretical number of stages and the optimum theoretical number of stages, the number of distillation groups is obtained. From the simulation, we postulate that 6 groups of distillation tower having 600 stages per one column are needed for the production of 90%-{sup 13}CH{sub 4}. (author). 18 refs., 33 figs., 9 tabs.

  13. Motility-Induced Phase Separation

    Science.gov (United States)

    Cates, Michael E.; Tailleur, Julien

    2015-03-01

    Self-propelled particles include both self-phoretic synthetic colloids and various microorganisms. By continually consuming energy, they bypass the laws of equilibrium thermodynamics. These laws enforce the Boltzmann distribution in thermal equilibrium: The steady state is then independent of kinetic parameters. In contrast, self-propelled particles tend to accumulate where they move more slowly. They may also slow down at high density for either biochemical or steric reasons. This creates positive feedback, which can lead to motility-induced phase separation (MIPS) between dense and dilute fluid phases. At leading order in gradients, a mapping relates variable-speed, self-propelled particles to passive particles with attractions. This deep link to equilibrium phase separation is confirmed by simulations but generally breaks down at higher order in gradients: New effects, with no equilibrium counterpart, then emerge. We give a selective overview of the fast-developing field of MIPS, focusing on theory and simulation but including a brief speculative survey of its experimental implications.

  14. Tools for Reactive Distillation Column Design: Graphical and Stage-to-Stage Computation Methods

    DEFF Research Database (Denmark)

    Sanchez Daza, O.; Cisneros, Eduardo Salvador P.; Hostrup, Martin

    2001-01-01

    Based on the element mass balance concept, a graphical design method and a stage-to-stage multicomponent design method for reactive distillation columns have been developed. For distillation columns comprising reactive and non-reactive stages, a simple design strategy based on reactive and non......-reactive bubble point calculations is proposed. This strategy tracks the conversion and temperature between the feed and the end stages of the column. An illustrative example highlights the verification of the design strategy through rigorous simulation....

  15. Isotope separation process

    International Nuclear Information System (INIS)

    Cox, D.M.; Maas, E.T.

    1982-01-01

    Processes are disclosed for the separation of isotopes of an element comprising vaporizing uranyl compounds having the formula (UO2a2)n, where a is a monovalent anion and n in an integer from 2 to 4, the compounds having an isotopically shifted infrared absorption spectrum associated with uranyl ions containing said element which is to be separated, and then irradiating the uranyl compound with infrared radiation which is preferentially absorbed by a molecular vibration of uranyl ions of the compound containing a predetermined isotope of that element so that excited molecules of the compound are provided which are enriched in the molecules of the compound containing that predetermined isotope, thus enabling separation of these excited molecules. The processes disclosed include separation of the excited molecules by irradiating under conditions such that the excited molecules dissociate, and also separating the excited molecules by a discrete separation step. The latter includes irradiating the excited molecules by a second infrared laser in order to convert the excited molecules into a separable product, or also by chemically converting the excited molecules, preferably by reaction with a gaseous reactant

  16. Fire on Stage

    Directory of Open Access Journals (Sweden)

    Nicholas Daly

    2017-12-01

    Full Text Available The nineteenth century theatre was fire-prone, to say the least. Across the century there were more than 1,100 major conflagrations in the world’s theatres, and countless smaller fires. In Great Britain almost every theatre seems to have burned down at some point. And yet, despite, or perhaps in part because of, this appalling record, fires were a staple feature of stage spectacle. Some plays placed them at the very centre of the entertainment, and as the century went on stage fires became more and more elaborate. Actual or simulated conflagrations were conjured up using a diverse array of technologies, some of them very simple, some depending on the most recent scientific discoveries. Here, I give a short tour of these technologies and their use in the plays of the period, and suggest some of the pleasures that they offered. While onstage flames could draw people in, offering an experience of immersive suspense, for instance, they also interrupted the dramatic flow, reminding audiences that they were seeing a performance, getting something for their money. To this extent, we are reminded that nineteenth-century drama provided something of a mixed and spectacular ‘theatre of attractions’, closer at times to the circus than to the novel.

  17. Deuterium isotope separation

    International Nuclear Information System (INIS)

    Benson, S.W.

    1979-01-01

    Deuterium-containing molecules are separated and enriched by exposing commercially available ethylene, vinyl chloride, 1,2-dichloroethane or propylene to the radiation of tuned infrared lasers to selectively decompose these compounds into enriched molecular products containing deuterium atoms. The deuterium containing molecules can be easily separated from the starting material by absorption, distillation or other simple chemical separation techniques and methods. After evaporation such deuterium containing molecules can be burned to form water with an enriched deuterium content or pyrolyzed to form hydrogen gas with an enriched deuterium content. (author)

  18. Isotope separation using lasers

    International Nuclear Information System (INIS)

    Guers, K.

    1976-01-01

    In laser isotope separation atoms or molecules of a specific isotopic species are selectively excited in a gaseous mixture by means of laser light and then separated from the mixture by physical or chemical methods. The methods of excitation and separation are described and compared in terms of their effectiveness. The use of molecules is investigated by analysing the possibility of the selective excitation of UF 6 . Finally, developments in this field are discussed together with the cost of research incurred in the United States and the economic benefit expected from this research. (author)

  19. Study on flow pattern and separation performance of air–water swirl-vane separator

    International Nuclear Information System (INIS)

    Xiong, Zhenqin; Lu, Mingchao; Wang, Minglu; Gu, Hanyang; Cheng, Xu

    2014-01-01

    Highlights: • A small-scale swirl-vane type steam separator is studied using air–water mixture. • The flow pattern inside the swirl-vane separator is analyzed. • Separation efficiency and pressure drop is experimentally obtained. • Separation efficiency is affected significantly by micro scale water droplets. • The separation efficiency predicted agrees well with the experimental results. - Abstract: Two-phase mixture has a complicated separating process inside a swirl-vane separator which plays an important role in assuring a low wetness of the steam to turbine. To understand the flow pattern inside the swirl-vane separator and analyze the separation performance, a simplified swirl-vane steam separator made of transparent acrylic resin is studied by experiment in which the mixture of air and water is used as the working fluids. Experimental results reveal that the separation efficiency of the separator strongly depends on the flow pattern and the water velocity. The separation efficiency in the annular flow is higher than that of the mist flow and the churn flow. The pressure drop is mainly affected by the air flow rate and the water droplet diameter. Furthermore, a numerical model assuming water as sphere droplets and neglecting its deformation is developed to simulate the separator with Euler two-phase model and RSM turbulence model. It is founded that although the separation efficiency is not sensitive to the size of the big water droplets, it is affected significantly by the micro scale water droplets. By assuming that 94% water droplet equals the Sauter mean diameter and the other 6% is 0.4 times of the Sauter mean diameter, the separation efficiency predicted agrees well with the experimental results for the studied case

  20. Separation by solvent extraction

    Science.gov (United States)

    Holt, Jr., Charles H.

    1976-04-06

    17. A process for separating fission product values from uranium and plutonium values contained in an aqueous solution, comprising adding an oxidizing agent to said solution to secure uranium and plutonium in their hexavalent state; contacting said aqueous solution with a substantially water-immiscible organic solvent while agitating and maintaining the temperature at from -1.degree. to -2.degree. C. until the major part of the water present is frozen; continuously separating a solid ice phase as it is formed; separating a remaining aqueous liquid phase containing fission product values and a solvent phase containing plutonium and uranium values from each other; melting at least the last obtained part of said ice phase and adding it to said separated liquid phase; and treating the resulting liquid with a new supply of solvent whereby it is practically depleted of uranium and plutonium.

  1. Separation by solvent extraction

    International Nuclear Information System (INIS)

    Holt, C.H. Jr.

    1976-01-01

    In a process for separating fission product values from U and Pu values contained in an aqueous solution, an oxidizing agent is added to the solution to secure U and Pu in their hexavalent state. The aqueous solution is contacted with a substantially water-immiscible organic solvent with agitation while the temperature is maintained at from -1 to -2 0 C until the major part of the water present is frozen. The solid ice phase is continuously separated as it is formed and a remaining aqueous liquid phase containing fission product values and a solvent phase containing Pu and U values are separated from each other. The last obtained part of the ice phase is melted and added to the separated liquid phase. The resulting liquid is treated with a new supply of solvent whereby it is practically depleted of U and Pu

  2. Partially separable t matrix

    International Nuclear Information System (INIS)

    Sasakawa, T.; Okuno, H.; Ishikawa, S.; Sawada, T.

    1982-01-01

    The off-shell t matrix is expressed as a sum of one nonseparable and one separable terms so that it is useful for applications to more-than-two body problems. All poles are involved in this one separable term. Both the nonseparable and the separable terms of the kernel G 0 t are regular at the origin. The nonseparable term of this kernel vanishes at large distances, while the separable term behaves asymptotically as the spherical Hankel function. These properties make our expression free from defects inherent in the Jost or the K-matrix expressions, and many applications are anticipated. As the application, a compact expression of the many-level formula is presented. Also the application is suggested to the breakup threebody problem based on the Faddeev equation. It is demonstrated that the breakup amplitude is expressed in a simple and physically interesting form and we can calculate it in coordinate space

  3. UWIS isotope separator

    International Nuclear Information System (INIS)

    Wojtasiewicz, A.

    1997-01-01

    Since 1995 the University of Warsaw Isotope Separator group has participated in the ISOL/IGISOL project at the Heavy Ion Cyclotron. This project consists in installation of an isotope separator (on line with cyclotron heavy ion beam) with a hot plasma ion source (ISOL system) and/or with an ion guide source (IGISOL system). In the report the short description of the present status of the project is presented

  4. Hydrogen separation process

    Science.gov (United States)

    Mundschau, Michael [Longmont, CO; Xie, Xiaobing [Foster City, CA; Evenson, IV, Carl; Grimmer, Paul [Longmont, CO; Wright, Harold [Longmont, CO

    2011-05-24

    A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

  5. Prostate cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000397.htm Prostate cancer staging To use the sharing features on this ... trials you may be able to join How Prostate Cancer Staging is Done Initial staging is based on ...

  6. On separable Pauli equations

    International Nuclear Information System (INIS)

    Zhalij, Alexander

    2002-01-01

    We classify (1+3)-dimensional Pauli equations for a spin-(1/2) particle interacting with the electro-magnetic field, that are solvable by the method of separation of variables. As a result, we obtain the 11 classes of vector-potentials of the electro-magnetic field A(t,x(vector sign))=(A 0 (t,x(vector sign)), A(vector sign)(t,x(vector sign))) providing separability of the corresponding Pauli equations. It is established, in particular, that the necessary condition for the Pauli equation to be separable into second-order matrix ordinary differential equations is its equivalence to the system of two uncoupled Schroedinger equations. In addition, the magnetic field has to be independent of spatial variables. We prove that coordinate systems and the vector-potentials of the electro-magnetic field providing the separability of the corresponding Pauli equations coincide with those for the Schroedinger equations. Furthermore, an efficient algorithm for constructing all coordinate systems providing the separability of Pauli equation with a fixed vector-potential of the electro-magnetic field is developed. Finally, we describe all vector-potentials A(t,x(vector sign)) that (a) provide the separability of Pauli equation, (b) satisfy vacuum Maxwell equations without currents, and (c) describe non-zero magnetic field

  7. Low Complexity Bayesian Single Channel Source Separation

    DEFF Research Database (Denmark)

    Beierholm, Thomas; Pedersen, Brian Dam; Winther, Ole

    2004-01-01

    We propose a simple Bayesian model for performing single channel speech separation using factorized source priors in a sliding window linearly transformed domain. Using a one dimensional mixture of Gaussians to model each band source leads to fast tractable inference for the source signals. Simul...

  8. Simulation reframed.

    Science.gov (United States)

    Kneebone, Roger L

    2016-01-01

    Simulation is firmly established as a mainstay of clinical education, and extensive research has demonstrated its value. Current practice uses inanimate simulators (with a range of complexity, sophistication and cost) to address the patient 'as body' and trained actors or lay people (Simulated Patients) to address the patient 'as person'. These approaches are often separate.Healthcare simulation to date has been largely for the training and assessment of clinical 'insiders', simulating current practices. A close coupling with the clinical world restricts access to the facilities and practices of simulation, often excluding patients, families and publics. Yet such perspectives are an essential component of clinical practice. This paper argues that simulation offers opportunities to move outside a clinical 'insider' frame and create connections with other individuals and groups. Simulation becomes a bridge between experts whose worlds do not usually intersect, inviting an exchange of insights around embodied practices-the 'doing' of medicine-without jeopardising the safety of actual patients.Healthcare practice and education take place within a clinical frame that often conceals parallels with other domains of expert practice. Valuable insights emerge by viewing clinical practice not only as the application of medical science but also as performance and craftsmanship.Such connections require a redefinition of simulation. Its essence is not expensive elaborate facilities. Developments such as hybrid, distributed and sequential simulation offer examples of how simulation can combine 'patient as body' with 'patient as person' at relatively low cost, democratising simulation and exerting traction beyond the clinical sphere.The essence of simulation is a purposeful design, based on an active process of selection from an originary world, abstraction of what is criterial and re - presentation in another setting for a particular purpose or audience. This may be done within

  9. A Comparison of Hybrid Reynolds Averaged Navier Stokes/Large Eddy Simulation (RANS/LES) and Unsteady RANS Predictions of Separated Flow for a Variable Speed Power Turbine Blade Operating with Low Inlet Turbulence Levels

    Science.gov (United States)

    2017-10-01

    Transition, separation, and complex flow physics occur with the variable-speed power-turbine (VSPT) due to operation at low Reynolds numbers and a...currently valid OMB control number . PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) October 2017 2. REPORT TYPE...Turbulence Levels 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) David T Booth 5d. PROJECT NUMBER 5e. TASK

  10. Stochastic separation theorems.

    Science.gov (United States)

    Gorban, A N; Tyukin, I Y

    2017-10-01

    The problem of non-iterative one-shot and non-destructive correction of unavoidable mistakes arises in all Artificial Intelligence applications in the real world. Its solution requires robust separation of samples with errors from samples where the system works properly. We demonstrate that in (moderately) high dimension this separation could be achieved with probability close to one by linear discriminants. Based on fundamental properties of measure concentration, we show that for M1-ϑ, where 1>ϑ>0 is a given small constant. Exact values of a,b>0 depend on the probability distribution that determines how the random M-element sets are drawn, and on the constant ϑ. These stochastic separation theorems provide a new instrument for the development, analysis, and assessment of machine learning methods and algorithms in high dimension. Theoretical statements are illustrated with numerical examples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.

    1977-01-01

    The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than nonexcited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 15 claims, 1 figure

  12. Isotope separation process

    International Nuclear Information System (INIS)

    Thomas, W.R.L.

    1979-01-01

    The instant invention relates to an improved process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same element in said material. More particularly, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by a step wherein more of the excited molecules than non-excited molecules are converted to a chemically different form which may be separated by means known in the art. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium

  13. Gas separation with membranes

    International Nuclear Information System (INIS)

    Schulz, G.; Michele, H.; Werner, U.

    1982-01-01

    Gas separation with membranes has already been tested in numerous fields of application, e.g. uranium enrichment of H 2 separation. In many of these processes the mass transfer units, so-called permeators, have to be connected in tandem in order to achieve high concentrations. A most economical operating method provides for each case an optimization of the cascades with regard to the membrane materials, construction and design of module. By utilization of the concentration gradient along the membrane a new process development has been accomplished - the continuously operating membrane rectification unit. Investment and operating costs can be reduced considerably for a number of separating processes by combining a membrane rectification unit with a conventional recycling cascade. However, the new procedure requires that the specifications for the module construction, flow design, and membrane properties be reconsidered. (orig.) [de

  14. Separable quadratic stochastic operators

    International Nuclear Information System (INIS)

    Rozikov, U.A.; Nazir, S.

    2009-04-01

    We consider quadratic stochastic operators, which are separable as a product of two linear operators. Depending on properties of these linear operators we classify the set of the separable quadratic stochastic operators: first class of constant operators, second class of linear and third class of nonlinear (separable) quadratic stochastic operators. Since the properties of operators from the first and second classes are well known, we mainly study the properties of the operators of the third class. We describe some Lyapunov functions of the operators and apply them to study ω-limit sets of the trajectories generated by the operators. We also compare our results with known results of the theory of quadratic operators and give some open problems. (author)

  15. Configuration of Air Microfluidic Chip for Separating and Grading Respirable Dust

    Science.gov (United States)

    Zhu, Xiaofeng; Jia, Yiting; Sun, Jianhai; Zhao, Peiyue; Liu, Jinhua; Zhang, Yanni; Ning, Zhanwu

    2018-03-01

    Particulate matter (PM) is a category of airborne pollutants, and fine particles that have a diameter of 2.5 μm (PM2.5) or smaller are especially damaging to human health because of their ability to penetrate deep into our respiratory system, Therefore, Monitoring of PM is very important. In this work, an air micro- fluidic PM sensor based on MEMS was proposed, and numerical model of the sensor was simulated accurately. The sensor was able to separate particles according to their sizes, and then transports and deposits the selected particles using thermophoretic precipitation onto the surface of a microfabricated mass-sensitive film bulk acoustic resonator (FBAR), precisely weighing and providing the concentration of PM. The PM sensor has double stage separation function, and the primary separator can separate the particles with size of less 10 μm from the particles, and the secondary can separate particles with size of less 2.5 μm from the particles.

  16. Electromagnetic separator of plasma

    International Nuclear Information System (INIS)

    Gasilin, V.V.; Nezovibatko, Yu.N.; Poklepach, G.S.; Shvets, O.M.; Taran, V.S.; Tereshin, V.I.

    2005-01-01

    The progress in the widespread utilization of the PVD methods is determined in many respects by the plasma quality and, therefore, the necessity of an application of plasma separators, in particular magnetic separators. One needs to note that traditional magnetic separators have a number of problems their using, namely their unwieldiness, the presence of the isolated cameras and so on. We have proposed, manufactured and investigated the simple separator of plasma that doesn't require using additional cameras. As a source of metallic plasma the standard cathode vaporizer in the installation 'BULAT 6' was in use. Plasma stream from the cathode flowed through the not protected by isolation spiral solenoid. The solenoid input (from the cathode side) was under floating potential. The solenoid output was connected to the autonomous power supply system. The solenoid was prepared with stride winding and 90 degree turn. The solenoid current was 20-90 A and the solenoid voltage with respect to the vessel (earth) was +15 V. In this case drifting charged particles could freely fly out from the interior solenoid region to its boundary. The glow of the turned flow of plasma was observed during the supplying of the cathode and the solenoid. Plasma flow was separated from the coils and extended along the axis of solenoid. One can assume that this device ensures radial electric with respect to the bulk of plasma (the diameter of the bulk of plasma is comparable with the cathode diameter), the toroidal magnetic field, produced by solenoid, was of an order of 20 Oe. Magnetic field strength was sufficient for the magnetization of electrons, but it was rather small for magnetizing the ions and charged micro-droplets. The experiments carried out with aluminum cathode on the deposition of coatings at the stainless steel substrate have shown the high effectiveness of this separator operation. Coatings without droplets were obtained also on the glass substrate with HF- displacement

  17. Between Stage and Screen

    NARCIS (Netherlands)

    Tornqvist, Egil

    1996-01-01

    Ingmar Bergman is worldwide known as a film and stage director. Yet no-one has attempted to compare his stage and screen activities. In Between stage and screen Egil Tornqvist examines formal and thematical correspondences and differences between a number of Bergman's stage, screen, and radio

  18. SEPARATION OF FLUID MIXTURES

    Science.gov (United States)

    Lipscomb, R.; Craig, A.; Labrow, S.; Dunn, J.F.

    1958-10-28

    An apparatus is presented for separating gaseous mixtures by selectively freezing a constituent of the mixture and subsequently separating the frozen gas. The gas mixture is passed through a cylinder fltted with a cooling jacket, causing one gas to freeze on the walls of the cylinder. A set of scraper blades are provided in the interior of the cyllnder, and as the blades oscillate, the frozen gas is scraped to the bottom of the cylinder. Means are provided for the frozen material to pass into a heating chamber where it is vaporized and the product gas collected.

  19. Gas separation membranes

    Science.gov (United States)

    Schell, William J.

    1979-01-01

    A dry, fabric supported, polymeric gas separation membrane, such as cellulose acetate, is prepared by casting a solution of the polymer onto a shrinkable fabric preferably formed of synthetic polymers such as polyester or polyamide filaments before washing, stretching or calendering (so called griege goods). The supported membrane is then subjected to gelling, annealing, and drying by solvent exchange. During the processing steps, both the fabric support and the membrane shrink a preselected, controlled amount which prevents curling, wrinkling or cracking of the membrane in flat form or when spirally wound into a gas separation element.

  20. Organic separations with membranes

    International Nuclear Information System (INIS)

    Funk, E.W.

    1993-01-01

    This paper presents an overview of present and emerging applications of membrane technology for the separation and purification of organic materials. This technology is highly relevant for programs aimed at minimizing waste in processing and in the treatment of gaseous and liquid effluents. Application of membranes for organic separation is growing rapidly in the petrochemical industry to simplify processing and in the treatment of effluents, and it is expected that this technology will be useful in numerous other industries including the processing of nuclear waste materials

  1. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.

    1976-01-01

    The instant invention relates to a process for separating a material into two or more parts in each of which the abundances of the isotopes of a given element differ from the abundances of the isotopes of the same material in said material. In one embodiment, the invention relates to a method for the isotopically selective excitation of gas phase molecules by multiple infrared photon absorption followed by selective dissociation of said excited molecules by the absorption of a single photon of visible or ultraviolet light. This invention is useful for, but not limited to, the separation of the principal isotopes of uranium. 11 Claims, 2 Drawing Figures

  2. Separation techniques: Chromatography

    Science.gov (United States)

    Coskun, Ozlem

    2016-01-01

    Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

  3. Numerical modeling, calibration, and validation of an ultrasonic separator

    NARCIS (Netherlands)

    Cappon, H.J.; Keesman, K.J.

    2013-01-01

    Our overall goal is to apply acoustic separation technology for the recovery of valuable particulate matter from wastewater in industry. Such large-scale separator systems require detailed design and evaluation to optimize the system performance at the earliest stage possible. Numerical models can

  4. Separation of an inulin mixture using cascaded nanofiltration

    NARCIS (Netherlands)

    Patil, N.V.; Feng, Xiaoxia; Sewalt, J.J.W.; Boom, R.M.; Janssen, A.E.M.

    2015-01-01

    This paper examines the use of a pilot-scale spiral wound nanofiltration cascade with regard to separation of mono- and disaccharides from a mixture of inulin of different polymer sizes. The choices of the membrane and operational conditions were based on single stage experiments. Two 3-stage

  5. Unity Through Separation

    DEFF Research Database (Denmark)

    Dabelsteen, Hans B.

    into the principle of treating everybody equally (with religious freedom, equality and Danish peoplehood as the most important principles adjacent to secularism). In a study of the historical roots of the separation doctrine and two current policy cases (same-sex marriage and reforms of church governance...

  6. Separation, Separatism and Diversity.

    Science.gov (United States)

    Hasegawa, Maya

    1991-01-01

    In the United States, once legal integration was achieved and the White male culture was challenged for real power, minority groups began to question the wisdom of cultural and social integration and celebrate diversity. An acceptable line between healthy separation and unhealthy separatism must be found. (MSE)

  7. diffusive phase separation

    Directory of Open Access Journals (Sweden)

    Nobuyuki Kenmochi

    1996-01-01

    w is constrained to have double obstacles σ*≤w≤σ* (i.e., σ* and σ* are the threshold values of w. The objective of this paper is to discuss the semigroup {S(t} associated with the phase separation model, and construct its global attractor.

  8. Radioactive krypton gas separation

    International Nuclear Information System (INIS)

    Martin, J.R.

    1976-01-01

    Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 16 Claims, 8 Drawing Figures

  9. Radioactive krypton gas separation

    International Nuclear Information System (INIS)

    Martin, J.R.

    1977-01-01

    Radioactive krypton is separated from a gas mixture comprising nitrogen and traces of carbon dioxide and radioactive krypton by first selective adsorption and then cryogenic distillation of the prepurified gas against nitrogen liquid to produce krypton bottoms concentrate liquid, using the nitrogen gas from the distillation for two step purging of the adsorbent. 6 claims, 8 drawing figures

  10. Hydrogen isotope separation

    Science.gov (United States)

    Bartlit, John R.; Denton, William H.; Sherman, Robert H.

    1982-01-01

    A system of four cryogenic fractional distillation columns interlinked with two equilibrators for separating a DT and hydrogen feed stream into four product streams, consisting of a stream of high purity D.sub.2, DT, T.sub.2, and a tritium-free stream of HD for waste disposal.

  11. Fathering After Marital Separation

    Science.gov (United States)

    Keshet, Harry Finkelstein; Rosenthal, Kristine M.

    1978-01-01

    Deals with experiences of a group of separated or divorced fathers who chose to remain fully involved in the upbringing of their children. As they underwent transition from married parenthood to single fatherhood, these men learned that meeting demands of child care contributed to personal stability and growth. (Author)

  12. Separation problems and forcing

    Czech Academy of Sciences Publication Activity Database

    Zapletal, Jindřich

    2013-01-01

    Roč. 13, č. 1 (2013), s. 1350002 ISSN 0219-0613 R&D Projects: GA AV ČR IAA100190902 Institutional research plan: CEZ:AV0Z10190503 Keywords : separation * set of uniqueness * forcing Subject RIV: BA - General Mathematics Impact factor: 0.364, year: 2012 http://www.worldscientific.com/doi/abs/10.1142/S0219061313500025

  13. Polymide gas separation membranes

    Science.gov (United States)

    Ding, Yong; Bikson, Benjamin; Nelson, Joyce Katz

    2004-09-14

    Soluble polyamic acid salt (PAAS) precursors comprised of tertiary and quaternary amines, ammonium cations, sulfonium cations, or phosphonium cations, are prepared and fabricated into membranes that are subsequently imidized and converted into rigid-rod polyimide articles, such as membranes with desirable gas separation properties. A method of enhancing solubility of PAAS polymers in alcohols is also disclosed.

  14. SELECTIVE SEPARATION, PRECONCENTRATION AND ...

    African Journals Online (AJOL)

    B. S. Chandravanshi

    ABSTRACT. A simple, sensitive, facile and low cost methodology, combined with flame atomic absorption spectrometry (FAAS), was employed to evaluate the selective separation and preconcentration of Pd(II) ions in environmental samples by using a triazole derivative as an organic coprecipitating agent without a carrier ...

  15. Separation of Powers.

    Science.gov (United States)

    Bill of Rights in Action, 1987

    1987-01-01

    The dimensions of the separation of powers principle are explored through three lessons in the subject areas of U.S. history, U.S. government, and world history. In 1748, a French nobleman, Baron de Montesquieu, wrote a book called "The Spirit of the Laws," in which he argued that there could be no liberty when all government power was…

  16. Big Data Blind Separation

    Directory of Open Access Journals (Sweden)

    Mujahid N. Syed

    2018-02-01

    Full Text Available Data or signal separation is one of the critical areas of data analysis. In this work, the problem of non-negative data separation is considered. The problem can be briefly described as follows: given X ∈ R m × N , find A ∈ R m × n and S ∈ R + n × N such that X = A S . Specifically, the problem with sparse locally dominant sources is addressed in this work. Although the problem is well studied in the literature, a test to validate the locally dominant assumption is not yet available. In addition to that, the typical approaches available in the literature sequentially extract the elements of the mixing matrix. In this work, a mathematical modeling-based approach is presented that can simultaneously validate the assumption, and separate the given mixture data. In addition to that, a correntropy-based measure is proposed to reduce the model size. The approach presented in this paper is suitable for big data separation. Numerical experiments are conducted to illustrate the performance and validity of the proposed approach.

  17. Estimation of Separation Buffers for Wind-Prediction Error in an Airborne Separation Assistance System

    Science.gov (United States)

    Consiglio, Maria C.; Hoadley, Sherwood T.; Allen, B. Danette

    2009-01-01

    Wind prediction errors are known to affect the performance of automated air traffic management tools that rely on aircraft trajectory predictions. In particular, automated separation assurance tools, planned as part of the NextGen concept of operations, must be designed to account and compensate for the impact of wind prediction errors and other system uncertainties. In this paper we describe a high fidelity batch simulation study designed to estimate the separation distance required to compensate for the effects of wind-prediction errors throughout increasing traffic density on an airborne separation assistance system. These experimental runs are part of the Safety Performance of Airborne Separation experiment suite that examines the safety implications of prediction errors and system uncertainties on airborne separation assurance systems. In this experiment, wind-prediction errors were varied between zero and forty knots while traffic density was increased several times current traffic levels. In order to accurately measure the full unmitigated impact of wind-prediction errors, no uncertainty buffers were added to the separation minima. The goal of the study was to measure the impact of wind-prediction errors in order to estimate the additional separation buffers necessary to preserve separation and to provide a baseline for future analyses. Buffer estimations from this study will be used and verified in upcoming safety evaluation experiments under similar simulation conditions. Results suggest that the strategic airborne separation functions exercised in this experiment can sustain wind prediction errors up to 40kts at current day air traffic density with no additional separation distance buffer and at eight times the current day with no more than a 60% increase in separation distance buffer.

  18. Separation science and technology

    International Nuclear Information System (INIS)

    Smith, B.F.; Sauer, N.; Chamberlin, R.M.; Gottesfeld, S.; Mattes, B.R.; Li, D.Q.; Swanson, B.

    1998-01-01

    The focus of this project is the demonstration and advancement of membrane-based separation and destruction technologies. The authors are exploring development of membrane systems for gas separations, selective metal ion recovery, and for separation or destruction of hazardous organics. They evaluated existing polymers and polymer formulations for recovery of toxic oxyanionic metals such as chromate and arsenate from selected waste streams and developed second-generation water-soluble polymeric systems for highly selective oxyanion removal and recovery. They optimized the simultaneous removal of radioactive strontium and cesium from aqueous solutions using the new nonhazardous separations agents, and developed recyclable, redox-active extractants that permitted recovery of the radioactive ions into a minimal waste volume. They produced hollow fibers and fabricated prototype hollow-fiber membrane modules for applications to gas separations and the liquid-liquid extraction and recovery of actinides and nuclear materials from process streams. They developed and fabricated cyclodextrin-based microporous materials that selectively absorb organic compounds in an aqueous environment; the resultant products gave pure water with organics at less than 0.05 parts per billion. They developed new, more efficient, membrane-based electrochemical reactors for use in organic destruction in process waste treatment. They addressed the need for advanced oxidation technologies based on molecular-level materials designs that selectively remove or destroy target species. They prepared and characterized surface-modified TiO 2 thin films using different linking approaches to attach ruthenium photosensitizers, and they started the measurement of the photo-degradation products generated using surface modified TiO 2 films in reaction with chlorophenol

  19. Separation science and technology

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F.; Sauer, N.; Chamberlin, R.M.; Gottesfeld, S.; Mattes, B.R.; Li, D.Q.; Swanson, B.

    1998-12-31

    The focus of this project is the demonstration and advancement of membrane-based separation and destruction technologies. The authors are exploring development of membrane systems for gas separations, selective metal ion recovery, and for separation or destruction of hazardous organics. They evaluated existing polymers and polymer formulations for recovery of toxic oxyanionic metals such as chromate and arsenate from selected waste streams and developed second-generation water-soluble polymeric systems for highly selective oxyanion removal and recovery. They optimized the simultaneous removal of radioactive strontium and cesium from aqueous solutions using the new nonhazardous separations agents, and developed recyclable, redox-active extractants that permitted recovery of the radioactive ions into a minimal waste volume. They produced hollow fibers and fabricated prototype hollow-fiber membrane modules for applications to gas separations and the liquid-liquid extraction and recovery of actinides and nuclear materials from process streams. They developed and fabricated cyclodextrin-based microporous materials that selectively absorb organic compounds in an aqueous environment; the resultant products gave pure water with organics at less than 0.05 parts per billion. They developed new, more efficient, membrane-based electrochemical reactors for use in organic destruction in process waste treatment. They addressed the need for advanced oxidation technologies based on molecular-level materials designs that selectively remove or destroy target species. They prepared and characterized surface-modified TiO{sub 2} thin films using different linking approaches to attach ruthenium photosensitizers, and they started the measurement of the photo-degradation products generated using surface modified TiO{sub 2} films in reaction with chlorophenol.

  20. SEPARATION OF SATURED AND UNSATURATED FATTY ACIDS FROM PALM FATTY ACIDS DISTILLATES IN CONTINUOUS MULTISTAGE COUNTERCURRENT COLUMNS WITH SUPERCRITICAL CARBON DIOXIDE AS SOLVENT: A PROCESS DESIGN METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Nélio Teixeira MACHADO

    1997-12-01

    Full Text Available In this work the separation of multicomponent mixtures in counter-current columns with supercritical carbon dioxide has been investigated using a process design methodology. First the separation task must be defined, then phase equilibria experiments are carried out, and the data obtained are correlated with thermodynamic models or empirical functions. Mutual solubilities, Ki-values, and separation factors aij are determined. Based on this data possible operating conditions for further extraction experiments can be determined. Separation analysis using graphical methods are performed to optimize the process parameters. Hydrodynamic experiments are carried out to determine the flow capacity diagram. Extraction experiments in laboratory scale are planned and carried out in order to determine HETP values, to validate the simulation results, and to provide new materials for additional phase equilibria experiments, needed to determine the dependence of separation factors on concetration. Numerical simulation of the separation process and auxiliary systems is carried out to optimize the number of stages, solvent-to-feed ratio, product purity, yield, and energy consumption. Scale-up and cost analysis close the process design. The separation of palmitic acid and (oleic+linoleic acids from PFAD-Palm Fatty Acids Distillates was used as a case study.

  1. EMC Simulation and Modeling

    Science.gov (United States)

    Takahashi, Takehiro; Schibuya, Noboru

    The EMC simulation is now widely used in design stage of electronic equipment to reduce electromagnetic noise. As the calculated electromagnetic behaviors of the EMC simulator depends on the inputted EMC model of the equipment, the modeling technique is important to obtain effective results. In this paper, simple outline of the EMC simulator and EMC model are described. Some modeling techniques of EMC simulation are also described with an example of the EMC model which is shield box with aperture.

  2. Reactor refueling machine simulator

    International Nuclear Information System (INIS)

    Rohosky, T.L.; Swidwa, K.J.

    1987-01-01

    This patent describes in combination: a nuclear reactor; a refueling machine having a bridge, trolley and hoist each driven by a separate motor having feedback means for generating a feedback signal indicative of movement thereof. The motors are operable to position the refueling machine over the nuclear reactor for refueling the same. The refueling machine also has a removable control console including means for selectively generating separate motor signals for operating the bridge, trolley and hoist motors and for processing the feedback signals to generate an indication of the positions thereof, separate output leads connecting each of the motor signals to the respective refueling machine motor, and separate input leads for connecting each of the feedback means to the console; and a portable simulator unit comprising: a single simulator motor; a single simulator feedback signal generator connected to the simulator motor for generating a simulator feedback signal in response to operation of the simulator motor; means for selectively connecting the output leads of the console to the simulator unit in place of the refueling machine motors, and for connecting the console input leads to the simulator unit in place of the refueling machine motor feedback means; and means for driving the single simulator motor in response to any of the bridge, trolley or hoist motor signals generated by the console and means for applying the simulator feedback signal to the console input lead associated with the motor signal being generated by the control console

  3. Method of cerium separation from other lanthanides and yttrium

    International Nuclear Information System (INIS)

    Tran, Duc Hiep; Mostecky, J.

    1988-01-01

    Cerium is separated from a suspension produced during the aerial oxidation process. The suspension is subject to a cyclic process of two-stage fractional dissolution. Following the first dissolution, almost all cerium remains undissolved while 95% of the other lanthanides pass into the solution. The filtrate of the second stage of dissolution containing about 5% of ceriumm is returned for oxidation with the next batch of hydroxide mixed concentrate. Following oxidation, the two-stage fractional dissolution is repeated. This cycling provides quantitative cerium separation from other rare earth elements. (E.S.)

  4. Attainability and minimum energy of single-stage membrane and membrane/distillation hybrid processes

    KAUST Repository

    Alshehri, Ali

    2014-12-01

    As an energy-efficient separation method, membrane technology has attracted more and more attentions in many challenging separation processes. The attainability and the energy consumption of a membrane process are the two basic fundamental questions that need to be answered. This report aims to use process simulations to find: (1) at what conditions a single-stage membrane process can meet the separation task that is defined by product purity and recovery ratio and (2) what are the most important parameters that determine the energy consumption. To perform a certain separation task, it was found that both membrane selectivity and pressure ratio exhibit a minimum value that is defined only by product purity and recovery ratio. The membrane/distillation hybrid system was used to study the energy consumption. A shortcut method was developed to calculate the minimum practical separation energy (MPSE) of the membrane process and the distillation process. It was found that the MPSE of the hybrid system is only determined by the membrane selectivity and the applied transmembrane pressure ratio in three stages. At the first stage when selectivity is low, the membrane process is not competitive to the distillation process. Adding a membrane unit to a distillation tower will not help in reducing energy. At the second medium selectivity stage, the membrane/distillation hybrid system can help reduce the energy consumption, and the higher the membrane selectivity, the lower is the energy. The energy conservation is further improved as pressure ratio increases. At the third stage when both selectivity and pressure ratio are high, the hybrid system will change to a single-stage membrane unit and this change will cause significant reduction in energy consumption. The energy at this stage keeps decreasing with selectivity at slow rate, but slightly increases with pressure ratio. Overall, the higher the membrane selectivity, the more the energy is saved. Therefore, the two

  5. Novel approach for modeling separation forces between deformable bodies.

    Science.gov (United States)

    Mahvash, Mohsen

    2006-07-01

    Many minimally invasive surgeries (MISs) involve removing whole organs or tumors that are connected to other organs. Development of haptic simulators that reproduce separation forces between organs can help surgeons learn MIS procedures. Powerful computational approaches such as finite-element methods generally cannot simulate separation in real time. This paper presents a novel approach for real-time computation of separation forces between deformable bodies. Separation occurs either due to fracture when a tool applies extensive forces to the bodies or due to evaporation when a laser beam burns the connection between the bodies. The separation forces are generated online from precalculated force-displacement functions that depend on the local adhesion/separation states between bodies. The precalculated functions are accurately synthesized from a large number of force responses obtained through either offline simulation, measurement, or analytical approximation during the preprocessing step. The approach does not require online computation of force versus global deformation to obtain separation forces. Only online interpolation of precalculated responses is required. The state of adhesion/separation during fracture and evaporation are updated by computationally simple models, which are derived based on the law of conservation of energy. An implementation of the approach for the haptic simulation of the removal of a diseased organ is presented, showing the fidelity of the simulation.

  6. Stable isotope separation

    International Nuclear Information System (INIS)

    Botter, F.; Molinari, Ph.; Dirian, G.

    1964-01-01

    Pure deuterium has been separated from gaseous mixtures of hydrogen and deuterium by band displacement chromatography, using columns of palladium on a support. The best results were obtained with columns of Pd on sintered α alumina. With a column of this type, of total capacity about 2 liters, a preparative apparatus of low dead volume has been built which produces 1 liter of pure D 2 from a 50 p. 100 D 2 , 50 p. 100 100 H 2 mixture in about 12 minutes. As a first approximation chromatography is likened theoretically to counter current fractionation, neglecting superficial resistance to the exchange. and also longitudinal diffusions. The number of theoretical plates required necessary for a certain enrichment of the gas phase is determined graphically or by calculation, enabling comparisons to be made between the efficiencies of columns containing different amounts of palladium. Thermal Diffusion: For the separation of hydrogen isotopes a thermal diffusion installation, made of stainless steel and entirely tele-commanded has been constructed. The separation cascade is made up of two identical pairs of hot wire columns. Each pair can work separately or they may be connected by a thermosyphon. The temperature of the hot wire is kept at around 1000 deg C by direct current. With this installation, hydrogen samples with a deuterium content lower than o,5 ppm were obtained from a gas originally containing 32 ppm. It was thus possible to prepare tritium of 99,3 p. 100 concentration from gas with an initial content of 6 p. 100. For quantitative separation of xenon enriched five time in 124 Xe by thermal diffusion, two identical cascades were constructed, each consisting of 5 columns, working in parallel and the two being connected by thermosyphon or by a capillary tube linked to a thermal gas oscillation. The central tungsten wire is heated to 1200 deg C. The columns are grouped like cluster of a heat exchanger, in shell of 30 cm diameter through which cooling water

  7. Combination of separating apparatuses

    International Nuclear Information System (INIS)

    Ishikura, Akira.

    1975-01-01

    Object: To increase a separating efficiency through a small piping, to uniform inlet and outlet of each separator and to prevent a chain destruction at the time of failure. Structure: Inner peripheral machines and outer peripheral machines of each centrifuge are alternately connected. Light gases and heavy gases from each inner peripheral machine are mixed and fed to the outer peripheral machines, whereas light gases and heavy gases from each outer peripheral machines are mixed and fed to the inner peripheral machines. In this case, cut value of light gases in the inner peripheral machine is less than 0.5 and cut value of light gases in the outer peripheral machine is from 0.5 to 1. (Furukawa, Y.)

  8. Process for isotope separation

    International Nuclear Information System (INIS)

    Emile, B.F.M.

    1983-11-01

    A process is claimed for isotopic separation applied to isotopes of elements that can be placed in at least a physicochemical form in which the isotopic atoms or the molecules containing these atoms can be easily displaced and for which there are selective radiations preferentially absorbed by the isotopes of a certain type or by the molecules containing them, said absorption substantially increasing the probability of ionization of said atoms or molecules relative to the atoms or molecules that did not absorb the radiation. The process consists of placing the isotopic mixture in such a form, subjecting it in a separation zone to selective radiations and to an electrical field that produces migration of positive ions toward the negative electrodes and negative ions toward the positive electrodes, and withdrawing from certain such zones the fractions thus enriched in certain isotopes

  9. Nylon separators. [thermal degradation

    Science.gov (United States)

    Lim, H. S.

    1977-01-01

    A nylon separator was placed in a flooded condition in K0H solution and heated at various high temperatures ranging from 60 C to 110 C. The weight decrease was measured and the molecular weight and decomposition product were analyzed to determine: (1) the effect of K0H concentration on the hydrolysis rate; (2) the effect of K0H concentration on nylon degradation; (3) the activation energy at different K0H concentrations; and (4) the effect of oxygen on nylon degradation. The nylon hydrolysis rate is shown to increase as K0H concentration is decreased 34%, giving a maximum rate at about 16%. Separator hydrolysis is confirmed by molecular weight decrease in age of the batteries, and the reaction of nylon with molecular oxygen is probably negligible, compared to hydrolysis. The extrapolated rate value from the high temperature experiment correlates well with experimental values at 35 degrees.

  10. Isotope separation process

    International Nuclear Information System (INIS)

    Kaldor, A.; Rabinowitz, P.

    1979-01-01

    A method of separating the isotopes of an element is described, which comprises the steps of (i) subjecting molecules of a gaseous compound of the element simultaneously to two infrared radiations of different wavelengths, the first radiation having a wavelength which corresponds to an absorption band of the compound, which in turn corresponds to a mode of molecular motion in which there is participation by atoms of the element, and the second radiation having a power density greater than 10 6 watts per cm 2 , thereby exciting molecules of the compound in an isotopically selective manner, this step being conducted in such manner that the excited molecules either receive a level of energy sufficient to cause them to undergo conversion by unimolecular decomposition or receive a level of energy sufficient to cause them to undergo conversion by reaction with molecules of another gas present for that purpose; and (ii) separating and recovering converted molecules from unconverted molecules. (author)

  11. Laser isotope separation process

    International Nuclear Information System (INIS)

    Kaldor, A.

    1976-01-01

    The claimed invention is a method of isotope separation based on the unimolecular decomposition of vibrationally excited negative ions which are produced in the reaction of thermal electrons and molecules which have been vibrationally excited in an isotope selective manner. This method is especially applicable to molecules represented by the formula MF 6 wherein M is selected from the group consisting of U, S, W, Se, Te, Mo, Re, and Tc. 9 claims, 1 drawing figure

  12. Infrared laser isotope separation

    International Nuclear Information System (INIS)

    Lyman, J.L.; Rockwood, S.D.

    1976-01-01

    An evaluation of isotope separation by selective molecular dissociation using CO 2 laser radiation is presented. Results of gaseous SF 6 irradiation in cylindrical cells are tabulated. The experiments were conducted using 25 percent SF 6 in H 2 irradiated by CO 2 laser pulses at 10.6 μm. Results show enhancements in reaction yield as high as 50, corresponding to a photon utilization efficiency of 0.5 percent

  13. Eddy energy separator

    Energy Technology Data Exchange (ETDEWEB)

    Mukhutdinov, R.Kh.; Prokopov, O.I.

    1982-01-01

    An eddy energy separator is proposed which contains a chamber with nozzle input of compressed air and sleeves for cold and hot streams. In order to increase productivity, the chamber is cylindrical and the nozzle input is arranged along its axis. Coaxially to the input, there is an adaptor forming an annular channel with its end arranged in an angle to the axis of the chamber. The nozzle input and the adaptor are installed with the possibility of relative movement.

  14. URANIUM SEPARATION PROCESS

    Science.gov (United States)

    Lyon, W.L.

    1962-04-17

    A method of separating uranium oxides from PuO/sub 2/, ThO/sub 2/, and other actinide oxides is described. The oxide mixture is suspended in a fused salt melt and a chlorinating agent such as chlorine gas or phosgene is sparged through the suspension. Uranium oxides are selectively chlorinated and dissolve in the melt, which may then be filtered to remove the unchlorinated oxides of the other actinides. (AEC)

  15. Separation of gas mixtures

    International Nuclear Information System (INIS)

    1981-01-01

    Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

  16. Colour Separation and Aversion

    Directory of Open Access Journals (Sweden)

    Sarah M Haigh

    2012-05-01

    Full Text Available Aversion to achromatic patterns is well documented but relatively little is known about discomfort from chromatic patterns. Large colour differences are uncommon in the natural environment and deviation from natural statistics makes images uncomfortable (Fernandez and Wilkins 2008, Perception, 37(7, 1098–113; Juricevic et al 2010, Perception, 39(7, 884–899. We report twelve studies documenting a linear increase in aversion to chromatic square-wave gratings as a function of the separation in UCS chromaticity between the component bars, independent of their luminance contrast. Two possible explanations for the aversion were investigated: (1 accommodative response, or (2 cortical metabolic demand. We found no correlation between chromaticity separation and accommodative lag or variance in lag, measured using an open-field autorefractor. However, near infrared spectroscopy of the occipital cortex revealed a larger oxyhaemoglobin response to patterns with large chromaticity separation. The aversion may be cortical in origin and does not appear to be due to accommodation.

  17. Innovative Separations Technologies

    Energy Technology Data Exchange (ETDEWEB)

    J. Tripp; N. Soelberg; R. Wigeland

    2011-05-01

    Reprocessing used nuclear fuel (UNF) is a multi-faceted problem involving chemistry, material properties, and engineering. Technology options are available to meet a variety of processing goals. A decision about which reprocessing method is best depends significantly on the process attributes considered to be a priority. New methods of reprocessing that could provide advantages over the aqueous Plutonium Uranium Reduction Extraction (PUREX) and Uranium Extraction + (UREX+) processes, electrochemical, and other approaches are under investigation in the Fuel Cycle Research and Development (FCR&D) Separations Campaign. In an attempt to develop a revolutionary approach to UNF recycle that may have more favorable characteristics than existing technologies, five innovative separations projects have been initiated. These include: (1) Nitrogen Trifluoride for UNF Processing; (2) Reactive Fluoride Gas (SF6) for UNF Processing; (3) Dry Head-end Nitration Processing; (4) Chlorination Processing of UNF; and (5) Enhanced Oxidation/Chlorination Processing of UNF. This report provides a description of the proposed processes, explores how they fit into the Modified Open Cycle (MOC) and Full Recycle (FR) fuel cycles, and identifies performance differences when compared to 'reference' advanced aqueous and fluoride volatility separations cases. To be able to highlight the key changes to the reference case, general background on advanced aqueous solvent extraction, advanced oxidative processes (e.g., volumetric oxidation, or 'voloxidation,' which is high temperature reaction of oxide UNF with oxygen, or modified using other oxidizing and reducing gases), and fluorination and chlorination processes is provided.

  18. Planck 2013 results. XII. Component separation

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

    2013-01-01

    foregrounds. This paper describes the component separation framework adopted by Planck. We test four foreground-cleaned CMB maps derived using qualitatively different component separation algorithms. The quality of our reconstructions is evaluated through detailed simulations and internal comparisons......, and shown through various tests to be internally consistent and robust for CMB power spectrum and cosmological parameter estimation up to l = 2000. The parameter constraints on LambdaCDM cosmologies derived from these maps are consistent with those presented in the cross-spectrum based Planck likelihood...

  19. Two-Stage Battery Energy Storage System (BESS in AC Microgrids with Balanced State-of-Charge and Guaranteed Small-Signal Stability

    Directory of Open Access Journals (Sweden)

    Bing Xie

    2018-02-01

    Full Text Available In this paper, a two-stage battery energy storage system (BESS is implemented to enhance the operation condition of conventional battery storage systems in a microgrid. Particularly, the designed BESS is composed of two stages, i.e., Stage I: integration of dispersed energy storage units (ESUs using parallel DC/DC converters, and Stage II: aggregated ESUs in grid-connected operation. Different from a conventional BESS consisting of a battery management system (BMS and power conditioning system (PCS, the developed two-stage architecture enables additional operation and control flexibility in balancing the state-of-charge (SoC of each ESU and ensures the guaranteed small-signal stability, especially in extremely weak grid conditions. The above benefits are achieved by separating the control functions between the two stages. In Stage I, a localized power sharing scheme based on the SoC of each particular ESU is developed to manage the SoC and avoid over-charge or over-discharge issues; on the other hand, in Stage II, an additional virtual impedance loop is implemented in the grid-interactive DC/AC inverters to enhance the stability margin with multiple parallel-connected inverters integrating at the point of common coupling (PCC simultaneously. A simulation model based on MATLAB/Simulink is established, and simulation results verify the effectiveness of the proposed BESS architecture and the corresponding control diagram.

  20. Breast cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000911.htm Breast cancer staging To use the sharing features on this ... Once your health care team knows you have breast cancer , they will do more tests to stage it. ...

  1. Seven Stages of Alzheimer's

    Science.gov (United States)

    ... Dementias . Learn more: Daily Care and Behaviors Severe Alzheimer's disease (late-stage) Get support Late-stage care decisions can be some of the hardest families face. Connect with other caregivers who have been through the process on our ...

  2. Stages of Adolescence

    Science.gov (United States)

    ... Español Text Size Email Print Share Stages of Adolescence Page Content Article Body Adolescence, these years from puberty to adulthood, may be roughly divided into three stages: early adolescence, generally ages eleven to fourteen; middle adolescence, ages ...

  3. Numerical analysis of wet separation of particles by density differences

    Science.gov (United States)

    Markauskas, D.; Kruggel-Emden, H.

    2017-07-01

    Wet particle separation is widely used in mineral processing and plastic recycling to separate mixtures of particulate materials into further usable fractions due to density differences. This work presents efforts aiming to numerically analyze the wet separation of particles with different densities. In the current study the discrete element method (DEM) is used for the solid phase while the smoothed particle hydrodynamics (SPH) is used for modeling of the liquid phase. The two phases are coupled by the use of a volume averaging technique. In the current study, simulations of spherical particle separation were performed. In these simulations, a set of generated particles with two different densities is dropped into a rectangular container filled with liquid. The results of simulations with two different mixtures of particles demonstrated how separation depends on the densities of particles.

  4. The ten stages pilot plant: its utilization in the research of the dynamic behavior and regullating process of a jet nozzle cascade for uranium enrichment

    International Nuclear Information System (INIS)

    Yadoya, R.; Camara, A.S.; Consiglio, R.V.; Bley, P.; Hein, H.; Linder, G.

    1986-01-01

    A ten stage pilot plant to study experimentally dynamic behavior of a uranium enrichment plant based on separation nozzle process was developed and constructed at Karlsruhe Nuclear Research Center. This installation was transfered to the Development Center of Nuclear Technology (CDTN) of Nuclebras in Belo Horizonte, Brazil. The separation elements installed have a new design with higher efficiency, Known as double-deflections system. The power plant has been used to improve the control method and to prove the stability of separation nozzle cascade under pertubations produced artificially. The stabilization process of UF 6 quantity in cascade by UF 6 inventory regulation at bottom stage will have practication in the First Cascade, in Rezende, RJ, Brazil and may be uded i emonstration plant. The experimental results have shown to be comparable with those obtained by computer simulation. (Author) [pt

  5. Development of Separation Materials Containing Palladium for Hydrogen Isotopes Separation

    International Nuclear Information System (INIS)

    Deng Xiaojun; Luo Deli; Qian Xiaojing

    2010-01-01

    Displacement chromatography (DC) is a ascendant technique for hydrogen isotopes separation. The performance of separation materials is a key factor to determine the separation effect of DC. At present,kinds of materials are researched, including palladium materials and non-palladium materials. It is hardly replaceable because of its excellent separation performance, although palladium is expensive. The theory of hydrogen isotopes separation using DC was introduced at a brief manner, while several palladium separation materials were expatiated in detail(Pd/K, Pd-Al 2 O 3 , Pd-Pt alloy). Development direction of separation materials for DC was forecasted elementarily. (authors)

  6. Beyond Erikson's Eight Stages.

    Science.gov (United States)

    Whitney, Ruth

    1979-01-01

    Erik Erikson has described eight stages of the healthy personality. This essay offers a revised version of the eight stages. Although most individuals develop through the eight stages, each is personally unique because patterns of fluctuation between safety and growth differ from one individual to another. (Author)

  7. Cervical Cancer Stage IIIA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIA Add to My Pictures View /Download : ... 1275x1275 View Download Large: 2550x2550 View Download Title: Cervical Cancer Stage IIIA Description: Stage IIIA cervical cancer; drawing ...

  8. Cervical Cancer Stage IVA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVA Add to My Pictures View /Download : ... 1575x1200 View Download Large: 3150x2400 View Download Title: Cervical Cancer Stage IVA Description: Stage IVA cervical cancer; drawing ...

  9. Cervical Cancer Stage IVB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVB Add to My Pictures View /Download : ... 1200x1305 View Download Large: 2400x2610 View Download Title: Cervical Cancer Stage IVB Description: Stage IVB cervical cancer; drawing ...

  10. Cervical Cancer Stage IIIB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIB Add to My Pictures View /Download : ... 1425x1326 View Download Large: 2850x2651 View Download Title: Cervical Cancer Stage IIIB Description: Stage IIIB cervical cancer; drawing ...

  11. Cervical Cancer Stage IB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IB Add to My Pictures View /Download : ... 1613x1200 View Download Large: 3225x2400 View Download Title: Cervical Cancer Stage IB Description: Stage IB1 and IB2 cervical ...

  12. Cervical Cancer Stage IA

    Science.gov (United States)

    ... historical Searches are case-insensitive Cervical Cancer Stage IA Add to My Pictures View /Download : Small: 720x576 ... Large: 3000x2400 View Download Title: Cervical Cancer Stage IA Description: Stage IA1 and IA2 cervical cancer; drawing ...

  13. SCFT simulation and SANS study on spatial distribution of solvents in microphase separation induced by a differentiating non-solvent in a semi-dilute solution of an ultra-high-molecular-weight block copolymer

    International Nuclear Information System (INIS)

    Ando, K; Yamanaka, T; Okamoto, S; Sakamoto, N; Yamaguchi, D; Koizumi, S; Hasegawa, H; Koshikawa, N

    2010-01-01

    Lyotropic order-disorder transition (ODT) in a semi-dilute solution of an ultra-high-molecular-weight block copolymer using a neutral solvent and a differentiating non-solvent was investigated. The role of the differentiating non-solvent in the ODT was revealed by the spatial distribution of the solvents simulated theoretically by the self-consistent field (SCF) theory approach and demonstrated experimentally by small-angle neutron scattering (SANS). The solutions of polystyrene-block-poly (tert-butyl methacrylate) (PS-b-PtBuMA) with an ultra-high-molecular-weight (UHMW) in a mixture of tetrahydrofuran (THF)/ water as a good and neutral solvent and a differentiating non-solvent, respectively, were used. The contrast variation method by SANS experimentally demonstrated that THF and water collectively move into the PtBuMA phase and that the volume fraction ratios of water to THF in both phases are almost equivalent to each other. This means that the solvent mixture of THF and water behaves as a single and strongly selective solvent. The collective movement of the solvents was well reproduced by the simulation. Interestingly, it was also suggested that THF gather in the vicinity of styrene-(tert-butyl methacrylate) interface to shield the unfavorable strong interaction between the PS and the PtBuMA phases and that water gather in the center of the PtBuMA phase to decrease the unfavorable contact with the PS phase.

  14. Integration of Weather Avoidance and Traffic Separation

    Science.gov (United States)

    Consiglio, Maria C.; Chamberlain, James P.; Wilson, Sara R.

    2011-01-01

    This paper describes a dynamic convective weather avoidance concept that compensates for weather motion uncertainties; the integration of this weather avoidance concept into a prototype 4-D trajectory-based Airborne Separation Assurance System (ASAS) application; and test results from a batch (non-piloted) simulation of the integrated application with high traffic densities and a dynamic convective weather model. The weather model can simulate a number of pseudo-random hazardous weather patterns, such as slow- or fast-moving cells and opening or closing weather gaps, and also allows for modeling of onboard weather radar limitations in range and azimuth. The weather avoidance concept employs nested "core" and "avoid" polygons around convective weather cells, and the simulations assess the effectiveness of various avoid polygon sizes in the presence of different weather patterns, using traffic scenarios representing approximately two times the current traffic density in en-route airspace. Results from the simulation experiment show that the weather avoidance concept is effective over a wide range of weather patterns and cell speeds. Avoid polygons that are only 2-3 miles larger than their core polygons are sufficient to account for weather uncertainties in almost all cases, and traffic separation performance does not appear to degrade with the addition of weather polygon avoidance. Additional "lessons learned" from the batch simulation study are discussed in the paper, along with insights for improving the weather avoidance concept. Introduction

  15. Eddy current separation apparatus, separation module, separation method and method for adjusting an eddy current separation apparatus

    NARCIS (Netherlands)

    Rem, P.C.; Bakker, M.C.M.; Berkhout, S.P.M.; Rahman, M.A.

    2012-01-01

    Eddy current separation apparatus (1) for separating particles (20) from a particle stream (w), wherein the apparatus (1) comprises a separator drum (4) adapted to create a first particle fraction (21) and a second particle fraction (23), a feeding device (2) upstream of the separator drum (4) for

  16. SEPARATION OF PLUTONIUM

    Science.gov (United States)

    Maddock, A.G.; Smith, F.

    1959-08-25

    A method is described for separating plutonium from uranium and fission products by treating a nitrate solution of fission products, uranium, and hexavalent plutonium with a relatively water-insoluble fluoride to adsorb fission products on the fluoride, treating the residual solution with a reducing agent for plutonium to reduce its valence to four and less, treating the reduced plutonium solution with a relatively insoluble fluoride to adsorb the plutonium on the fluoride, removing the solution, and subsequently treating the fluoride with its adsorbed plutonium with a concentrated aqueous solution of at least one of a group consisting of aluminum nitrate, ferric nitrate, and manganous nitrate to remove the plutonium from the fluoride.

  17. URANIUM SEPARATION PROCESS

    Science.gov (United States)

    Hyde, E.K.; Katzin, L.I.; Wolf, M.J.

    1959-07-14

    The separation of uranium from a mixture of uranium and thorium by organic solvent extraction from an aqueous solution is described. The uranium is separrted from an aqueous mixture of uranium and thorium nitrates 3 N in nitric acid and containing salting out agents such as ammonium nitrate, so as to bring ihe total nitrate ion concentration to a maximum of about 8 N by contacting the mixture with an immiscible aliphatic oxygen containing organic solvent such as diethyl carbinol, hexone, n-amyl acetate and the like. The uranium values may be recovered from the organic phase by back extraction with water.

  18. Isotope separation process

    International Nuclear Information System (INIS)

    Lyon, R.K.; Kaldor, A.

    1977-01-01

    In a method for the separation of isotopes of uranium in UF 6 , the UF 6 is subjected to ir radiation at a predetermined wavelength or set of wavelengths for less than 10 -3 sec in such a manner that at least 0.1% of the 235 UF 6 molecules absorb an energy of more than 2000 cm -1 . The excited UF 6 is then reacted with a gaseous reagent, F 2 , Cl 2 , or Br 2 , to produce a product which is then recovered by means known in the art

  19. Rolling Process Modeling Report: Finite-Element Prediction of Roll Separating Force and Rolling Defects

    Energy Technology Data Exchange (ETDEWEB)

    Soulami, Ayoub [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lavender, Curt A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Paxton, Dean M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Burkes, Douglas [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-04-23

    Pacific Northwest National Laboratory (PNNL) has been investigating manufacturing processes for the uranium-10% molybdenum (U-10Mo) alloy plate-type fuel for the U.S. high-performance research reactors. This work supports the Convert Program of the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) Global Threat Reduction Initiative. This report documents modeling results of PNNL’s efforts to perform finite-element simulations to predict roll separating forces and rolling defects. Simulations were performed using a finite-element model developed using the commercial code LS-Dyna. Simulations of the hot rolling of U-10Mo coupons encapsulated in low-carbon steel have been conducted following two different schedules. Model predictions of the roll-separation force and roll-pack thicknesses at different stages of the rolling process were compared with experimental measurements. This report discusses various attributes of the rolled coupons revealed by the model (e.g., dog-boning and thickness non-uniformity).

  20. Pilot-scale multistage membrane process for the separation of CO2 from LNG-fired flue gas

    KAUST Repository

    Choi, Seung Hak

    2013-06-01

    In this study, a multistage pilot-scale membrane plant was constructed and operated for the separation of CO2 from Liquefied Natural Gas (LNG)-fired boiler flue gas of 1000 Nm3/day. The target purity and recovery of CO2 were 99 vol.% and 90%, respectively. For this purpose, asymmetric polyethersulfone (PES) hollow fibers membranes has been developed in our previous work and has evaluated the effects of operating pressure and feed concentration of CO2 on separation performance. The operating and permeation data obtained were also analyzed in relation with the numerical simulation data using countercurrent flow model. Based on these results, in this study, four-staged membrane process including dehumidification process has been designed, installed, and operated to demonstrate the feasibility of multistage membrane systems for removing CO2 from flue gases. The operation results using this plant were compared to the numerical simulation results on multistage membrane process. The experimental results matched well with the numerical simulation data. The concentration and the recovery of CO2 in the permeate stream of final stage were ranged from 95-99 vol.% and 70-95%, respectively, depending on the operating conditions. This study demonstrated the applicability of the membrane-based pilot plant for CO2 recovery from flue gas. © 2013 Elsevier B.V. All rights reserved.

  1. Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Stage IB, Stage II, Stage III, or Stage IVA Cervical Cancer

    Science.gov (United States)

    2014-12-29

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  2. Application of electrostatic separation to the recycling of plastic wastes: separation of PVC, PET, and ABS.

    Science.gov (United States)

    Park, Chul-Hyun; Jeon, Ho-Seok; Yu, Hyo-Shin; Han, Oh-Hyung; Park, Jai-Koo

    2008-01-01

    Plastics are widely used in everyday life as a useful material, and thus their consumption is growing at a rate of about 5% per year in Korea. However, the constant generation of plastic wastes and their disposal generates environmental problems along with economic loss. In particular, mixed waste plastics are difficult to recycle because of their inferior characteristics. A laboratory-scale triboelectrostatic separator unit has been designed and assembled for this study. On the basis of the control of electrostatic charge, the separation of three kinds of mixed plastics, polyvinyl chloride (PVC), poly(ethylene terephthalate) (PET), and acrylonitrile-butadiene-styrene (ABS), in a range of similar gravities has been performed through a two-stage separation process. Polypropylene (PP) and high-impact polystyrene (HIPS) were found to be the most effective materials for a tribo-charger in the separation of PVC, PET, and ABS. The charge-to-mass ratio (nC/g) of plastics increased with increasing air velocity in the tribo charger. In the first stage, using the PP cyclone charger, the separation efficiency of particles considerably depended on the air velocity (10 m/s), the relative humidity ( 20 kV), and the splitter position (+2 cm from the center) in the triboelelctrostatic separator unit. At this time, a PVC grade of 99.40% and a recovery of 98.10% have successfully been achieved. In the second stage, using the HIPS cyclone charger, a PET grade of 97.80% and a recovery of 95.12% could be obtained under conditions of 10 m/s, over 25 kV, a central splitter position, and less than 40% relative humidity. In order to obtain 99.9% PVC grade and 99.3% PET grade, their recoveries should be sacrificed by 20.9% and 27%, respectively, with moving the splitter from the center to a (+)6 cm position.

  3. Isotope separation process

    International Nuclear Information System (INIS)

    Wexler, Sol; Young, C.E.

    1976-01-01

    Description is given of method for separating a specific isotope from a mixture of isotopes of an actinide element present as MF 6 , wherein M is the actinide element. It comprises: preparing a feed gas mixture of MF 6 in a propellant gas; passing the feed gas mixture under pressure through an expansion nozzle while heating the mixture to about 600 0 C; releasing the heated gas mixture from the nozzle into an exhaust chamber having a reduced pressure, whereby a gas jet of MF 6 molecules, MF 6 molecular clusters and propellant gas molecules is formed, the MF 6 molecules having a translational energy of about 3 eV; converting the MF 6 molecules to MF 6 ions by passing the jet through a cross jet of electron donor atoms so that an electron transfer takes place between the MF 6 - molecules and the electron donor atoms whereby the jet is now quasi-neutral, containing negative MF 6 - ions and positive donor ions; passing the quasi-neutral jet through a radiofrequency mass filter tuned to separate the MF 6 ions containing the specific isotope from the MF 6 - ions of the other isotopes and neutralizing and collecting the MF 6 molecules of the specific isotope [fr

  4. Printed Spacecraft Separation System

    Energy Technology Data Exchange (ETDEWEB)

    Dehoff, Ryan R [ORNL; Holmans, Walter [Planetary Systems Corporation

    2016-10-01

    In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly into a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.

  5. Feasibility study of iron mineral separation from red mud by high gradient superconducting magnetic separation

    Energy Technology Data Exchange (ETDEWEB)

    Li Yiran, E-mail: lyr2006xd@yahoo.com.c [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Jun, E-mail: junwang@rcees.ac.c [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China); Wang Xiaojun; Wang Baoqiang; Luan Zhaokun [State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085 (China)

    2011-02-15

    Research highlights: {yields} Red mud residues (RM) were disposed in alumina production. {yields} Utilization of Red mud residues was affected by its iron content. {yields} Superconducting magnetic separation (HGSMS) was used in iron separation from RM. {yields} RM with high and low iron contents were separated in HGSMS. - Abstract: The disposal of bayer red mud tailings now seriously threats the environment safety. Reduction and recycling of red mud is now an urgent work in aluminum industry. High gradient superconducting magnetic separation (HGSMS) system was applied to separate the extreme fine RM particles (<100 {mu}m) into high iron content part and low iron content part. Two sorts of RM were fed in the HGSMS. The iron oxide contents in concentrates were about 65% and 45% when RM 1 and RM 2 were fed respectively. Meanwhile, the residues contained 52.0% or 14.1% iron oxide in residues after eight separation stages when RM 1 and RM 2 were fed respectively. The mass recovery of iron concentrates was about 10% after once separation process regardless of RM 1 or RM 2 was fed. Extreme fine particles (<10 {mu}m) could be captured in the HGSMS. Intergrowth of Fe and other elements is disadvantages for iron mineral separation from RM by HGSMS. Some improvement should be studied to enhance the efficiency of iron separation. It is possible for HGSMS to separate RM into high iron content part and low iron content part, the former part could be used in iron-making furnace and the later part could be recycling to sintering process for alumina production or used as construction material.

  6. Projective synchronization based on suitable separation

    International Nuclear Information System (INIS)

    Li Guohui; Xiong Chuan; Sun Xiaonan

    2007-01-01

    A new approach for constructing a projective-synchronized chaotic slave system is proposed in this paper. This method is based on suitable separation by decomposing the system as the linear part and the nonlinear one. From matrix measure theory, some simple but efficient criteria are derived for projective synchronization of chaotic system. Numerical simulations for the Lorenz system show that this control method works very well

  7. Design of the SUPERB Recoil Separator

    Science.gov (United States)

    Jackson, Zachary; Carpenter, Lisa; Amthor, Matt

    2013-10-01

    The reaccelerator ReA12 upgrade planned at the National Superconducting Cyclotron Lab (NSCL) at Michigan State University will produce higher energy rare isotope beams close to the neutron and proton drip lines. We present one option for the recoil separator which aims to take full advantage of the new capabilities of ReA12 in studying rare isotopes. The Separator for Unique Products of Experiments with Radioactive Beams (SUPERB), patterned after the second half of the Super Separator-Spectrometer (S3) currently under construction at the Grand Accélérateur National d'Ions Lourds (GANIL). This design includes both electric and magnetic dipoles and this will allow physical separation by mass-to-charge ratio (m/q) with a maximum solid angle of 26 msr and a maximum magnetic rigidity of 1.44 Tm. This design also allows for flexibility of optical modes. Both large acceptance and unit magnification modes will be presented. Also, a fully magnetic configuration is considered that would eliminate the expected electric rigidity limit of 10 MV and increase the maximum magnetic rigidity to 1.92 Tm. We will present optical designs and simulations of SUBERB developed in the code COSY Infinity including a first order system and a higher order Monte Carlo calculation simulating 100Sn production. This research was funded by the NSF REU program, grant PHY-1165694 with additional support from the DoD ASSURE program.

  8. Computational Screening of MOFs for Acetylene Separation

    Science.gov (United States)

    Nemati Vesali Azar, Ayda; Keskin, Seda

    2018-01-01

    Efficient separation of acetylene (C2H2) from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600–1,200 m2/g and porosities between 0.4 and 0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials. PMID:29536004

  9. Computational Screening of MOFs for Acetylene Separation.

    Science.gov (United States)

    Nemati Vesali Azar, Ayda; Keskin, Seda

    2018-01-01

    Efficient separation of acetylene (C 2 H 2 ) from CO 2 and CH 4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C 2 H 2 /CO 2 and C 2 H 2 /CH 4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C 2 H 2 /CO 2 and C 2 H 2 /CH 4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C 2 H 2 /CO 2 and C 2 H 2 /CH 4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C 2 H 2 /CO 2 selectivities of 49, 47, 24 and C 2 H 2 /CH 4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C 2 H 2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600-1,200 m 2 /g and porosities between 0.4 and 0.6 for selective separation of C 2 H 2 from CO 2 and CH 4 . These results will guide the future studies for the design of new MOFs with high C 2 H 2 separation potentials.

  10. Computational Screening of MOFs for Acetylene Separation

    Directory of Open Access Journals (Sweden)

    Ayda Nemati Vesali Azar

    2018-02-01

    Full Text Available Efficient separation of acetylene (C2H2 from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600–1,200 m2/g and porosities between 0.4 and 0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials.

  11. Producing fuel alcohol by extractive distillation: Simulating the process with glycerol

    Directory of Open Access Journals (Sweden)

    Ana María Uyazán

    2006-01-01

    Full Text Available Downstream separation processes in biotechnology form part of the stages having most impact on a product’s final cost. The tendency throughout the world today is to replace fossil fuels with those having a renewable origin such as ethanol; this, in turn, produces a demand for the same and the need for optimising fermentation, treating vinazas and dehydration processes. The present work approaches the problem of dehydration through simulating azeotropic ethanol extractive distillation using glycerol as separation agent. Simulations were done on an Aspen Plus process simulator (Aspen Tech version 11.1. The simulated process involves two distillation columns, a dehydrator and a glycerol recuperation column. Simulation restrictions were ethanol’s molar composition in dehydrator column distillate and the process’s energy consumption. The effect of molar reflux ratio, solvent-feed ratio, solvent entry and feed stage and solvent entry temperature were evaluated on the chosen restrictions. The results showed that the ethanol-water mixture dehydration with glycerol as separation agent is efficient from the energy point of view.

  12. Adsorption Model for Off-Gas Separation

    Energy Technology Data Exchange (ETDEWEB)

    Veronica J. Rutledge

    2011-03-01

    The absence of industrial scale nuclear fuel reprocessing in the U.S. has precluded the necessary driver for developing the advanced simulation capability now prevalent in so many other countries. Thus, it is essential to model complex series of unit operations to simulate, understand, and predict inherent transient behavior and feedback loops. A capability of accurately simulating the dynamic behavior of advanced fuel cycle separation processes will provide substantial cost savings and many technical benefits. The specific fuel cycle separation process discussed in this report is the off-gas treatment system. The off-gas separation consists of a series of scrubbers and adsorption beds to capture constituents of interest. Dynamic models are being developed to simulate each unit operation involved so each unit operation can be used as a stand-alone model and in series with multiple others. Currently, an adsorption model has been developed in gPROMS software. Inputs include gas stream constituents, sorbent, and column properties, equilibrium and kinetic data, and inlet conditions. It models dispersed plug flow in a packed bed under non-isothermal and non-isobaric conditions for a multiple component gas stream. The simulation outputs component concentrations along the column length as a function of time from which the breakthrough data is obtained. It also outputs temperature along the column length as a function of time and pressure drop along the column length. Experimental data will be input into the adsorption model to develop a model specific for iodine adsorption on silver mordenite as well as model(s) specific for krypton and xenon adsorption. The model will be validated with experimental breakthrough curves. Another future off-gas modeling goal is to develop a model for the unit operation absorption. The off-gas models will be made available via the server or web for evaluation by customers.

  13. DRY FLUORINE SEPARATION METHOD

    Science.gov (United States)

    Seaborg, G.T.; Gofman, J.W.; Stoughton, R.W.

    1959-05-19

    Preparation and separation of U/sup 233/ by irradiation of ThF/sub 4/ is described. During the neutron irradiation to produce Pa/sup 233/ a fluorinating agent such as HF, F/sub 2/, or HF + F/sub 2/ is passed through the ThF/sub 4/ powder to produce PaF/sub 5/. The PaF/sub 5/, being more volatile, is removed as a gas and allowed to decay radioactively to U/sup 233/ fluoride. A batch procedure in which ThO/sub 2/ or Th metal is irradiated and fluorinated is suggested. Some Pa and U fluoride volatilizes away. Then the remainder is fluorinated with F/sub 2/ to produce very volatile UF/sub 6/ which is recovered. (T.R.H.)

  14. Nebulized therapy. SEPAR year.

    Science.gov (United States)

    Olveira, Casilda; Muñoz, Ana; Domenech, Adolfo

    2014-12-01

    Inhaled drugs are deposited directly in the respiratory tract. They therefore achieve higher concentrations with faster onset of action and fewer side effects than when used systemically. Nebulized drugs are mainly recommended for patients that require high doses of bronchodilators, when they need to inhale drugs that only exist in this form (antibiotics or dornase alfa) or when they are unable to use other inhalation devices. Technological development in recent years has led to new devices that optimize pulmonary deposits and reduce the time needed for treatment. In this review we focus solely on drugs currently used, or under investigation, for nebulization in adult patients; basically bronchodilators, inhaled steroids, antibiotics, antifungals, mucolytics and others such as anticoagulants, prostanoids and lidocaine. Copyright © 2014 SEPAR. Published by Elsevier Espana. All rights reserved.

  15. Separations canyon decontamination facilities

    International Nuclear Information System (INIS)

    Hershey, J.H.

    1975-01-01

    Highly radioactive process equipment is decontaminated at the Savannah River Plant in specially equipped areas of the separations canyon building so that direct mechanical repairs or alterations can be made. Using these facilities it is possible to decontaminate and repair equipment such as 10- x 11-ft storage tanks, 8- x 8-ft batch evaporator pots and columns, 40-in. Bird centrifuges, canyon pumps and agitators, and various canyon piping systems or ''jumpers.'' For example, centrifuge or evaporator pots can be decontaminated and rebuilt for about 60 percent of the 1974 replacement cost. The combined facilities can decontaminate and repair 6 to 10 pieces of major equipment per year. Decontamination time varies with type of equipment and radioactivity levels encountered

  16. Apparatus for diffusion separation

    International Nuclear Information System (INIS)

    Nierenberg, W.A.; Pontius, R.B.

    1976-01-01

    The method of testing the separation efficiency of porous permeable membranes is described which comprises causing a stream of a gaseous mixture to flow into contact with one face of a finely porous permeable membrane under such conditions that a major fraction of the mixture diffuses through the membrane, maintaining a rectangular cross section of the gaseous stream so flowing past said membrane, continuously recirculating the gas that diffuses through said membrane and continuously withdrawing the gas that does not diffuse through said membrane and maintaining the volume of said recirculating gas constant by continuously introducing into said continuously recirculating gas stream a mass of gas equivalent to that which is continuously withdrawn from said gas stream and comparing the concentrations of the light component in the entering gas, the withdrawn gas and the recirculated gas in order to determine the efficiency of said membrane

  17. Separations canyon decontamination facilities

    International Nuclear Information System (INIS)

    Hershey, J.H.

    1975-05-01

    Highly radioactive process equipment is decontaminated at the Savannah River Plant in specially equipped areas of the separations canyon buildings so that direct mechanical repairs or alterations can be made. Using these facilities it is possible to decontaminate and repair equipment such as 10- x 11-ft storage tanks, 8- x 8-ft batch evaporator pots and columns, 40-in. Bird centrifuges, canyon pumps and agitators, and various canyon piping systems or ''jumpers.'' For example, centrifuge or evaporator pots can be decontaminated and rebuilt for about 60 percent of the 1974 replacement cost. The combined facilities can decontaminate and repair 6 to 10 pieces of major equipment per year. Decontamination time varies with type of equipment and radioactivity levels encountered. (U.S.)

  18. Advanced isotope separation

    International Nuclear Information System (INIS)

    1982-01-01

    The Study Group briefly reviewed the technical status of the three Advanced Isotope Separation (AIS) processes. It also reviewed the evaluation work that has been carried out by DOE's Process Evaluation Board (PEB) and the Union Carbide Corporation-Nuclear Division (UCCND). The Study Group briefly reviewed a recent draft assessment made for DOE staff of the nonproliferation implications of the AIS technologies. The staff also very briefly summarized the status of GCEP and Advanced Centrifuge development. The Study Group concluded that: (1) there has not been sufficient progress to provide a firm scientific, technical or economic basis on which to select one of the three competing AIS processes for full-scale engineering development at this time; and (2) however, should budgetary restraints or other factors force such a selection, we believe that the evaluation process that is being carried out by the PEB provides the best basis available for making a decision. The Study Group recommended that: (1) any decisions on AIS processes should include a comparison with gas centrifuge processes, and should not be made independently from the plutonium isotope program; (2) in evaluating the various enrichment processes, all applicable costs (including R and D and sales overhead) and an appropriate discounting approach should be included in order to make comparisons on a private industry basis; (3) if the three AIS programs continue with limited resources, the work should be reoriented to focus only on the most pressing technical problems; and (4) if a decision is made to develop the Atomic Vapor Laser Isotope Separation process, the solid collector option should be pursued in parallel to alleviate the potential program impact of liquid collector thermal control problems

  19. Actinide separation by electrorefining

    International Nuclear Information System (INIS)

    Fusselman, S.P.; Gay, R.L.; Grantham, L.F.; Grimmett, D.L.; Roy, J.J.; Inoue, T.; Hijikata, T.; Krueger, C.L.; Storvick, T.S.; Takahashi, N.

    1995-01-01

    TRUMP-S is a pyrochemical process being developed for the recovery of actinides from PUREX wastes. This paper describes development of the electrochemical partitioning step for recovery of actinides in the TRUMP-S process. The objectives are to remove 99 % of each actinide from PUREX wastes, with a product that is > 90 % actinides. Laboratory tests indicate that > 99 % of actinides can be removed in the electrochemical partitioning step. A dynamic (not equilibrium) process model predicts that 90 wt % product actinide content can be achieved through 99 % actinide removal. Accuracy of model simulation results were confirmed in tests with rare earths. (authors)

  20. Fast Noise Compensation and Adaptive Enhancement for Speech Separation

    Directory of Open Access Journals (Sweden)

    Hu Rong

    2008-01-01

    Full Text Available We propose a novel approach to improve adaptive decorrelation filtering- (ADF- based speech source separation in diffuse noise. The effects of noise on system adaptation and separation outputs are handled separately. First, fast noise compensation (NC is developed for adaptation of separation filters, forcing ADF to focus on source separation; next, output noises are suppressed by speech enhancement. By tracking noise components in output cross-correlation functions, the bias effect of noise on the system adaptation objective function is compensated, and by adaptively estimating output noise autocorrelations, the speech separation output is enhanced. For fast noise compensation, a blockwise fast ADF (FADF is implemented. Experiments were conducted on real and simulated diffuse noises. Speech mixtures were generated by convolving TIMIT speech sources with acoustic path impulse responses measured in a real room with reverberation time  second. The proposed techniques significantly improved separation performance and phone recognition accuracy of ADF outputs.