WorldWideScience

Sample records for non-minimum phase systems

  1. Stable Inversion of MIMO Linear Discrete Time Non-Minimum Phase Systems

    NARCIS (Netherlands)

    George, Koshy; Verhaegen, Michel; Scherpen, Jacquelien M.A.

    1999-01-01

    A novel technique to achieve output tracking via stable inversion of non-minimum phase linear systems is presented wherein the desired signal is obtained from field measurements, and hence corrupted by noise. The earlier approach to stable inversion does not take into account the noise in the system

  2. A unified model-free controller for switching minimum phase, non-minimum phase and time-delay systems

    CERN Document Server

    Michel, Loïc

    2012-01-01

    This preliminary work presents a simple derivation of the standard model-free control in order to control switching minimum phase, non-minimum phase and time-delay systems. The robustness of the proposed method is studied in simulation.

  3. Robustification and Optimization in Repetitive Control For Minimum Phase and Non-Minimum Phase Systems

    Science.gov (United States)

    Prasitmeeboon, Pitcha

    repetitive control FIR compensator. The aim is to reduce the final error level by using real time frequency response model updates to successively increase the cutoff frequency, each time creating the improved model needed to produce convergence zero error up to the higher cutoff. Non-minimum phase systems present a difficult design challenge to the sister field of Iterative Learning Control. The third topic investigates to what extent the same challenges appear in RC. One challenge is that the intrinsic non-minimum phase zero mapped from continuous time is close to the pole of repetitive controller at +1 creating behavior similar to pole-zero cancellation. The near pole-zero cancellation causes slow learning at DC and low frequencies. The Min-Max cost function over the learning rate is presented. The Min-Max can be reformulated as a Quadratically Constrained Linear Programming problem. This approach is shown to be an RC design approach that addresses the main challenge of non-minimum phase systems to have a reasonable learning rate at DC. Although it was illustrated that using the Min-Max objective improves learning at DC and low frequencies compared to other designs, the method requires model accuracy at high frequencies. In the real world, models usually have error at high frequencies. The fourth topic addresses how one can merge the quadratic penalty to the Min-Max cost function to increase robustness at high frequencies. The topic also considers limiting the Min-Max optimization to some frequencies interval and applying an FIR zero-phase low-pass filter to cutoff the learning for frequencies above that interval.

  4. Observation and output adaptive tracking for a class of nonlinear non-minimum phase systems

    Science.gov (United States)

    Bartolini, G.; Estrada, A.; Punta, E.

    2016-09-01

    In this paper, the output tracking problem for a class of systems with unstable zero dynamics is addressed. The state is assumed not measurable. The output of the dynamical system to be controlled has to track a signal, which is the sum of a known number of sinusoids with unknown frequencies, amplitudes and phases. The non-minimum phase nature of the considered systems prevents the direct tracking by standard sliding mode methods, which are known to generate unstable behaviours of the internal dynamics. The proposed method relies on the availability of a flat output and its time derivatives which are functions of the unavailable state; therefore, a nonlinear observer is needed. Due to the uncertainty in the frequencies and in the parameters defining the relationship between the output of the system and the flat states, adaptive indirect methods are applied.

  5. Design of Critical Control Systems for Non-Minimum Phase Plants via LTR Technique

    Science.gov (United States)

    Ishihara, Tadashi; Ono, Takahiko

    An application of the loop transfer recovery (LTR) technique to critical control systems design is proposed for non-minimum phase plants. The controller structure is chosen as the Davison type integral controller with the Kalman filter. First, a critical control system is designed on the assumption that the state of the minimum phase part of the plant can be used for the feedback. A quadratic performance index with tuning parameters is used for determining the partial state feedback gain matrix. Second, the Kalman filter gain matrix is determined such that the output feedback controller performs as in the partial state feedback controller. The formal partial loop recovery procedure using the Riccati equation is adopted for this purpose. The proposed design method requires much simpler numerical search than the conventional one-step approach. An illustrative design example is presented.

  6. Combined feedforward and model-assisted active disturbance rejection control for non-minimum phase system.

    Science.gov (United States)

    Sun, Li; Li, Donghai; Gao, Zhiqiang; Yang, Zhao; Zhao, Shen

    2016-09-01

    Control of the non-minimum phase (NMP) system is challenging, especially in the presence of modelling uncertainties and external disturbances. To this end, this paper presents a combined feedforward and model-assisted Active Disturbance Rejection Control (MADRC) strategy. Based on the nominal model, the feedforward controller is used to produce a tracking performance that has minimum settling time subject to a prescribed undershoot constraint. On the other hand, the unknown disturbances and uncertain dynamics beyond the nominal model are compensated by MADRC. Since the conventional Extended State Observer (ESO) is not suitable for the NMP system, a model-assisted ESO (MESO) is proposed based on the nominal observable canonical form. The convergence of MESO is proved in time domain. The stability, steady-state characteristics and robustness of the closed-loop system are analyzed in frequency domain. The proposed strategy has only one tuning parameter, i.e., the bandwidth of MESO, which can be readily determined with a prescribed robustness level. Some comparative examples are given to show the efficacy of the proposed method. This paper depicts a promising prospect of the model-assisted ADRC in dealing with complex systems.

  7. Fault diagnosis for non-minimum phase systems using ℋ∞ optimization

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Stoustrup, Jakob

    2001-01-01

    The analysis and design algorithms for residual generators for nonminimum phase systems are given. It is shown that the ℋ∞ optimization of residual generators applied directly to systems including nonminimum phase zeros can be very conservative. To remove this conservatism in the ℋ∞ opt...

  8. Non-Minimum Phase Nonlinear System Predictive Control Based on Local Recurrent Neural Networks

    Institute of Scientific and Technical Information of China (English)

    张燕; 陈增强; 袁著祉

    2003-01-01

    After a recursive multi-step-ahead predictor for nonlinear systems based on local recurrent neural networks is introduced, an intelligent PID controller is adopted to correct the errors including identified model errors and accumulated errors produced in the recursive process. Characterized by predictive control, this method can achieve a good control accuracy and has good robustness. A simulation study shows that this control algorithm is very effective.

  9. Analysis of Non-minimum Phase in Buck-Boost Converter

    OpenAIRE

    2016-01-01

    In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode,the negative regulation voltage is det...

  10. Analysis of Non-minimum Phase in Buck-Boost Converter

    Directory of Open Access Journals (Sweden)

    Huang Jinfeng

    2016-01-01

    Full Text Available In this paper, relations among the parameters of the non-minimum phase for the Buck-Boost converter are studied. It is demonstrated that when the Buck-Boost converter works in Buck mode, the negative regulation voltage is determined by the converter with the pre-designed inductor and load as the duty ratio D0.382, and the duty ratio has a limited effect on the negative regulation voltage of the converter; when the Buck-Boost converter works in Boost mode,the negative regulation voltage is determined jointly by the converter with its pre-designed inductor, load and duty cycle, for which performs that the higher the output voltage is (i.e., the greater the duty ratio is,the more severe undershoot of the voltage will be. The conclusion of this paper has a guidance meaning for decreasing the negative regulation voltage of the Buck-Boost converter. Finally the correctness of the analysis for the non-minimum phase is verified by simulations and experiments.

  11. Parameter selection and analysis of non-minimum phase for Boost converter%Boost变换器的参数选择与非最小相位分析

    Institute of Scientific and Technical Information of China (English)

    皇金锋; 刘树林

    2014-01-01

    In order to improve the Boost converter 's transient performance and reduce the negative over-shoot effect because of non-minimum-phase reaction on system, the small signal mathematics model of Boost converter worked in inductor current continuous mode was established with pulse waveform integral method. The transfer functions from input to output and from control to output were obtained. The theo-retical basis for the Boost converter transient performance optimization was provided. The effect of transi-ent performances and negative over-shoot on there parameters such as inductance, capacitance, load, du-ty ratio and frequency were analyzed with the mathematics model. Research results show that the larger the inductance, the heavy load, large duty can make the system zero near the origin, and the over-shoot phenomenon is more obvious because of non-minimum-phase reaction on system. Different capacitance values have an impact on transient performance and output voltage ripple and have no effect on the over-shoot phenomenon. The principle of parameter selection for improving system transient performance and reducing non-minimum-phase reaction were given. The theoretical basis for optimal design of Boost con-verter was provided. The simulation and experimental results verify the rationality of the parameter selec-tion.%为了提高Boost变换器的暂态性能,减小非最小相位反应引起的负调对系统的影响,利用脉冲波形积分法建立了Boost变换器工作在电感电流连续模式下的小信号数学模型,获得了系统输入-输出以及控制-输出的传递函数,为Boost变换器暂态性能优化提供了理论依据。利用该模型分析了电感、电容、负载、占空比、频率等参数对系统暂态性能和系统非最小相位引起的负调电压的影响。研究结果表明:较大的电感、最重负载、较大的占空比使得系统的零点更靠近原点,系统的非最小相位反应即负调现象更

  12. 一类非最小相位随机系统的离散自适应滑动模态控制%Discrete Sliding Mode Control of an Input-output System with Stochastic Disturbance

    Institute of Scientific and Technical Information of China (English)

    蔡素芬; 张志平; 尹增刚

    2006-01-01

    This paper presents the discrete adaptive sliding mode control of input-output non-minimum phase system in the presence of the stochastic disturbance. The non-minimum phase system can be transformed into a minimum phase system by a operator. According to the minimum phase system, the controller and the adaptive algorithm we designed ensures the stability of system and holds that the mean-square deviation from the sliding surface is minimized.

  13. Phase Transitions of Simple Systems

    CERN Document Server

    Berry, Stephen

    2008-01-01

    This monograph develops a unified microscopic basis for phases and phase changes of bulk matter and small systems in terms of classical physics. The origins of such phase changes are derived from simple but physically relevant models of how transitions between rigid crystalline, glassy and fluid states occur, how phase equilibria arise, and how bulk properties evolve from those of small systems.

  14. Phase control of excitable systems

    Energy Technology Data Exchange (ETDEWEB)

    Zambrano, S; Seoane, J M; Marino, I P; Sanjuan, M A F [Nonlinear Dynamics and Chaos Group, Departamento de Fisica, Universidad Rey Juan Carlos, Tulipan s/n, 28933 Mostoles, Madrid (Spain); Euzzor, S; Meucci, R; Arecchi, F T [CNR-Istituto Nazionale di Ottica Applicata, Largo E. Fermi, 6 50125 Firenze (Italy)], E-mail: samuel.zambrano@urjc.es, E-mail: jesus.seoane@urjc.es, E-mail: ines.perez@urjc.es

    2008-07-15

    Here we study how to control the dynamics of excitable systems by using the phase control technique. Excitable systems are relevant in neuronal dynamics and therefore this method might have important applications. We use the periodically driven FitzHugh-Nagumo (FHN) model, which displays both spiking and non-spiking behaviours in chaotic or periodic regimes. The phase control technique consists of applying a harmonic perturbation with a suitable phase {phi} that we adjust in search of different behaviours of the FHN dynamics. We compare our numerical results with experimental measurements performed on an electronic circuit and find good agreement between them. This method might be useful for a better understanding of excitable systems and different phenomena in neuronal dynamics.

  15. Phase transitions in finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire

    2002-07-01

    In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

  16. Design of RTDA controller for industrial process using SOPDT model with minimum or non-minimum zero.

    Science.gov (United States)

    Anbarasan, K; Srinivasan, K

    2015-07-01

    This research paper focuses on the design and development of simplified RTDA control law computation formulae for SOPDT process with minimum or non-minimum zero. The design of RTDA control scheme consists of three main components namely process output prediction, model prediction update and control action computation. The systematic approach for computation of the above three components for SOPDT process with minimum or non-minimum zero is developed in this paper. The design, implementation and performance evaluation of the developed controller is demonstrated via simulation examples. The closed loop equation, block diagram representation and theoretical stability derivation for RTDA controller are developed. The performance of proposed controller is compared with IMC, SPC, MPC and PID controller and it is demonstrated on Industrial non-linear CSTR process.

  17. Three-phase Photovoltaic Systems

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Máthé, Lászlo

    2015-01-01

    the grid through a three-phase power electronic converter are now well on the way to becoming a major player in the power system in many countries. Therefore, this article gives an overview of photovoltaic systems with a focus on three-phase applications, presenting these both from a hardware point of view......Photovoltaic technology has experienced unprecedented growth in the last two decades, transforming from mainly off-grid niche generation to a major renewable energy technology, reaching approximately 180 GW of capacity worldwide at the end of 2014. Large photovoltaic power plants interfacing......, detailing the different photovoltaic inverter structures and topologies as well as discussing the different control layers within a grid-connected photovoltaic plant. Modulation schemes for various photovoltaic inverter topologies, grid synchronization, current control, active and reactive power control...

  18. Phase control system for SSRF linac

    Institute of Scientific and Technical Information of China (English)

    YIN Chongxian; YU Luyang; LIU Dekang

    2008-01-01

    The design of phase control system in Shanghai Synchrotron Radiation Facility (SSRF) linac is presented in this paper. And digital phase detecting algorithm, the key for phase control system, is fully described. The testing results for phase control system in 100MeV linac are discussed in detail.

  19. Phase Multistability in Coupled Oscillator Systems

    DEFF Research Database (Denmark)

    Mosekilde, Erik; Postnov, D.E.; Sosnovtseva, Olga

    2003-01-01

    The phenomenon of phase multistability arises in connection with the synchronization of coupled oscillator systems when the systems individually display complex wave forms associated, for instance, with the presence of subharmonic components or with significant variations of the phase velocity...

  20. Enhanced IMC based PID controller design for non-minimum phase (NMP) integrating processes with time delays.

    Science.gov (United States)

    Ghousiya Begum, K; Seshagiri Rao, A; Radhakrishnan, T K

    2017-03-18

    Internal model control (IMC) with optimal H2 minimization framework is proposed in this paper for design of proportional-integral-derivative (PID) controllers. The controller design is addressed for integrating and double integrating time delay processes with right half plane (RHP) zeros. Blaschke product is used to derive the optimal controller. There is a single adjustable closed loop tuning parameter for controller design. Systematic guidelines are provided for selection of this tuning parameter based on maximum sensitivity. Simulation studies have been carried out on various integrating time delay processes to show the advantages of the proposed method. The proposed controller provides enhanced closed loop performances when compared to recently reported methods in the literature. Quantitative comparative analysis has been carried out using the performance indices, Integral Absolute Error (IAE) and Total Variation (TV).

  1. Phase Noise in Photonic Phased-Array Antenna Systems

    Science.gov (United States)

    Logan, Ronald T., Jr.; Maleki, Lute

    1998-01-01

    The total noise of a phased-array antenna system employing a photonic feed network is analyzed using a model for the individual component noise including both additive and multiplicative equivalent noise generators.

  2. Phases, phase equilibria, and phase rules in low-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, T., E-mail: timfrol@berkeley.edu [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Mishin, Y., E-mail: ymishin@gmu.edu [Department of Physics and Astronomy, MSN 3F3, George Mason University, Fairfax, Virginia 22030 (United States)

    2015-07-28

    We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.

  3. Phases, phase equilibria, and phase rules in low-dimensional systems.

    Science.gov (United States)

    Frolov, T; Mishin, Y

    2015-07-28

    We present a unified approach to thermodynamic description of one, two, and three dimensional phases and phase transformations among them. The approach is based on a rigorous definition of a phase applicable to thermodynamic systems of any dimensionality. Within this approach, the same thermodynamic formalism can be applied for the description of phase transformations in bulk systems, interfaces, and line defects separating interface phases. For both lines and interfaces, we rigorously derive an adsorption equation, the phase coexistence equations, and other thermodynamic relations expressed in terms of generalized line and interface excess quantities. As a generalization of the Gibbs phase rule for bulk phases, we derive phase rules for lines and interfaces and predict the maximum number of phases than may coexist in systems of the respective dimensionality.

  4. Phase Diagrams of Silicate Systems: Handbook; Third Issue; Ternary Systems

    Science.gov (United States)

    In the third issue of the handbook Phase Diagrams of Silicate Systems, information is included on the phase relationships in systems containing...radioelectronics, nuclear engineering, etc. Not only are equilibrium phase diagrams presented in the handbook, but the phases existing in the

  5. Oscillating systems with cointegrated phase processes

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Rahbek, Anders; Ditlevsen, Susanne

    2017-01-01

    We present cointegration analysis as a method to infer the network structure of a linearly phase coupled oscillating system. By defining a class of oscillating systems with interacting phases, we derive a data generating process where we can specify the coupling structure of a network that resemb......We present cointegration analysis as a method to infer the network structure of a linearly phase coupled oscillating system. By defining a class of oscillating systems with interacting phases, we derive a data generating process where we can specify the coupling structure of a network...

  6. Phase control system concepts and simulations. [solar power satellite system

    Science.gov (United States)

    Lindsay, V. C.

    1980-01-01

    A phase control system concept for a solar power satellite is proposed which partitions the system into three major levels. The first level of phase control consists of a reference phase distribution system implemented in the form of phase distribution tree structure. The major purpose of the tree structure is to electronically compensate for the phase shift due to the transition path lengths from the center of the spacetenna to each phase control center located in each subarray. In the reference system, this is accomplished using the master slave returnable timing system technique. The second level of phase control consists of the beam steering and microwave power generating system which houses the power transponders. This transponder consists of a set of phase conjugation multipliers driven by the reference phase distribution system output and the output of a pilot spread spectrum receiver which accepts the received pilot via a diplexer connected to a separate receive horn or the subarray itself. The output of the phase conjugation circuits serve as inputs to the third level of the phase control system. The third level of phase control is associated with maintaining an equal and constant phase shift through the microwave power amplifier devices while minimizing the associated phase noise effects on the generated power beam. This is accomplished by providing a phase locked loop around each high power amplifier.

  7. Phase-Modulated Optical Communication Systems

    CERN Document Server

    Ho, Keang-Po

    2005-01-01

    Fiber-optic communication systems have revolutionized our telecommunication infrastructures – currently, almost all telephone land-line, cellular, and internet communications must travel via some form of optical fibers. In these transmission systems, neither the phase nor frequency of the optical signal carries information – only the intensity of the signal is used. To transmit more information in a single optical carrier, the phase of the optical carrier must be explored. As a result, there is renewed interest in phase-modulated optical communications, mainly in direct-detection DPSK signals for long-haul optical communication systems. When optical amplifiers are used to maintain certain signal level among the fiber link, the system is limited by amplifier noises and fiber nonlinearities. Phase-Modulated Optical Communication Systems surveys this newly popular area, covering the following topics: The transmitter and receiver for phase-modulated coherent lightwave systems Method for performance analysis o...

  8. Cycle slipping in phase synchronization systems

    Science.gov (United States)

    Yang, Ying; Huang, Lin

    2007-02-01

    Cycle slipping is a characteristically nonlinear phenomenon in phase synchronization systems, which is highly dependent of the initial state of the system. Slipping a cycle means that the phase error is increased to such an extent that the generator to be synchronized slips one complete cycle with respect to the input phase. In this Letter, a linear matrix inequality (LMI) based approach is proposed and the estimation of the number of cycles which slips a solution of the system is obtained by solving a quasi-convex optimization problem of LMI. Applications to phase locked loops demonstrate the validity of the proposed approach.

  9. Two-phase flow in refrigeration systems

    CERN Document Server

    Gu, Junjie; Gan, Zhongxue

    2013-01-01

    Two-Phase Flow in Refrigeration Systems presents recent developments from the authors' extensive research programs on two-phase flow in refrigeration systems. This book covers advanced mass and heat transfer and vapor compression refrigeration systems and shows how the performance of an automotive air-conditioning system is affected through results obtained experimentally and theoretically, specifically with consideration of two-phase flow and oil concentration. The book is ideal for university postgraduate students as a textbook, researchers and professors as an academic reference book, and b

  10. Phase synchronization in time-delay systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M; Kurths, J

    2006-09-01

    Though the notion of phase synchronization has been well studied in chaotic dynamical systems without delay, it has not been realized yet in chaotic time-delay systems exhibiting non-phase-coherent hyperchaotic attractors. In this paper we report identification of phase synchronization in coupled time-delay systems exhibiting hyperchaotic attractor. We show that there is a transition from nonsynchronized behavior to phase and then to generalized synchronization as a function of coupling strength. These transitions are characterized by recurrence quantification analysis, by phase differences based on a transformation of the attractors, and also by the changes in the Lyapunov exponents. We have found these transitions in coupled piecewise linear and in Mackey-Glass time-delay systems.

  11. Phase balancing optimization for radial feeder systems

    Science.gov (United States)

    Zhu, Jinxiang

    In the power distribution systems, unbalanced feeder causes deteriorating power quality and increases investment and operating costs. There are two approaches to balance a feeder system. One approach is feeder reconfiguration, the other is phase swapping. Feeder reconfiguration is an on-line operation of sectionalizing switches. However, feeder reconfiguration is difficult to find the phase balancing solution for a unbalanced feeder system. On the other hand, phase swapping is a direct and effective approach for phase balancing. Phase swapping is an off-line operation of re-tapping loads/laterals to the phase lines during maintenance and restoration periods. Unfortunately, phase balancing problem has not received its deserved importance. Deregulation in power industry has arisen phase balancing issue because it can improve power quality, improve service reliability, and reduce total costs. Thus, phase balancing can enhance utility competitive capability. This research provides utilities the optimization tools to maximize the benefits of phase balancing and minimize the costs. This dissertation proposed several mathematical formulations, including Mixed-integer programming (MIP), Dynamic programming (DP), Simulated annealing (SA), and Fuzzy logic (FL), to perform phase swapping to balance phase in a radial feeder. Due to the discrete nature of phase swapping, a MIP model is proposed to find the optimal phase swapping scheme for small-sized feeder. Candidate sets and monitored branches are then introduced to solve the large-scale feeder systems. Possibilistic integer programming (PIP) is proposed to incorporate load uncertainties in phase swapping problems. The tests show that the load uncertainties may change the optimal phase swapping. DP computation is significant reduced by introducing the tighter upper/lower bounds. The upper bound can be quickly obtained by assignment algorithm. Even though SA is a time-consuming heuristic method, it can provide better solution

  12. Vapor phase heat transport systems

    Energy Technology Data Exchange (ETDEWEB)

    Hedstrom, J.C.; Neeper, D.A.

    1985-09-01

    This report describes progress in theoretical and experimental investigations of various forms of a vapor transport system for solar space heating, which could also be applied to service water heating. Refrigerant is evaporated in a solar collector, which may be located on the external wall or roof of a building. The vapor is condensed in a passively discharged thermal storage unit located within the building. The condensed liquid can be returned to the collector either by a motor-driven pump or by a completely passive self-pumping mechanism in which the vapor pressure lifts the liquid from the condenser to the collector. The theoretical investigation analyzes this self-pumping scheme. Experiments in solar test cells compare the operation of both passive and active forms of the vapor system with the operation of a passive water wall. The vapor system operates as expected, with potential advantages over other passive systems in design flexibility and energy yield.

  13. Quantum Phase Transitions in a Finite System

    CERN Document Server

    Leviatan, A

    2006-01-01

    A general procedure for studying finite-N effects in quantum phase transitions of finite systems is presented and applied to the critical-point dynamics of nuclei undergoing a shape-phase transition of second-order (continuous), and of first-order with an arbitrary barrier.

  14. Chaotic systems in complex phase space

    CERN Document Server

    Bender, Carl M; Hook, Daniel W; Weir, David J

    2008-01-01

    This paper examines numerically the complex classical trajectories of the kicked rotor and the double pendulum. Both of these systems exhibit a transition to chaos, and this feature is studied in complex phase space. Additionally, it is shown that the short-time and long-time behaviors of these two PT-symmetric dynamical models in complex phase space exhibit strong qualitative similarities.

  15. Optimizing discrete control systems with phase limitations

    Energy Technology Data Exchange (ETDEWEB)

    Shakhverdian, S.B.; Abramian, A.K.

    1981-01-01

    A new method is proposed for solving discrete problems of optimizing control systems with limitations on the phase coordinates. Results are given from experimental research which demonstrate the need to introduce tangential limitations independent of the method of accounting for the phase limitations.

  16. Geometric phases in discrete dynamical systems

    Energy Technology Data Exchange (ETDEWEB)

    Cartwright, Julyan H.E., E-mail: julyan.cartwright@csic.es [Instituto Andaluz de Ciencias de la Tierra, CSIC–Universidad de Granada, E-18100 Armilla, Granada (Spain); Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, E-18071 Granada (Spain); Piro, Nicolas, E-mail: nicolas.piro@epfl.ch [École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne (Switzerland); Piro, Oreste, E-mail: piro@imedea.uib-csic.es [Departamento de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Tuval, Idan, E-mail: ituval@imedea.uib-csic.es [Mediterranean Institute for Advanced Studies, CSIC–Universitat de les Illes Balears, E-07190 Mallorca (Spain)

    2016-10-14

    In order to study the behaviour of discrete dynamical systems under adiabatic cyclic variations of their parameters, we consider discrete versions of adiabatically-rotated rotators. Parallelling the studies in continuous systems, we generalize the concept of geometric phase to discrete dynamics and investigate its presence in these rotators. For the rotated sine circle map, we demonstrate an analytical relationship between the geometric phase and the rotation number of the system. For the discrete version of the rotated rotator considered by Berry, the rotated standard map, we further explore this connection as well as the role of the geometric phase at the onset of chaos. Further into the chaotic regime, we show that the geometric phase is also related to the diffusive behaviour of the dynamical variables and the Lyapunov exponent. - Highlights: • We extend the concept of geometric phase to maps. • For the rotated sine circle map, we demonstrate an analytical relationship between the geometric phase and the rotation number. • For the rotated standard map, we explore the role of the geometric phase at the onset of chaos. • We show that the geometric phase is related to the diffusive behaviour of the dynamical variables and the Lyapunov exponent.

  17. Phased array based ultrasound scanning system development

    Science.gov (United States)

    Sagdiev, R. K.; Denisov, E. S.; Evdokimov, Yu K.; Fazlyyyakhmatov, M. G.; Kashapov, N. F.

    2014-12-01

    Multichannel ultrasound scanning system based on phased arrays development is presented in this paper. Substantiation of system parameters is presented. The description of block diagram and hardware development is presented. The combination of the self-developed receiving and a transmitting units and commercially available FPGA unit and Personal Computer can solve our scientific goals, while providing a relatively low device cost.

  18. Ka-Band Phased Array System Characterization

    Science.gov (United States)

    Acosta, R.; Johnson, S.; Sands, O.; Lambert, K.

    2001-01-01

    Phased Array Antennas (PAAs) using patch-radiating elements are projected to transmit data at rates several orders of magnitude higher than currently offered with reflector-based systems. However, there are a number of potential sources of degradation in the Bit Error Rate (BER) performance of the communications link that are unique to PAA-based links. Short spacing of radiating elements can induce mutual coupling between radiating elements, long spacing can induce grating lobes, modulo 2 pi phase errors can add to Inter Symbol Interference (ISI), phase shifters and power divider network introduce losses into the system. This paper describes efforts underway to test and evaluate the effects of the performance degrading features of phased-array antennas when used in a high data rate modulation link. The tests and evaluations described here uncover the interaction between the electrical characteristics of a PAA and the BER performance of a communication link.

  19. Chaotic systems in complex phase space

    Indian Academy of Sciences (India)

    Carl M Bender; Joshua Feinberg; Daniel W Hook; David J Weir

    2009-09-01

    This paper examines numerically the complex classical trajectories of the kicked rotor and the double pendulum. Both of these systems exhibit a transition to chaos, and this feature is studied in complex phase space. Additionally, it is shown that the short-time and long-time behaviours of these two $\\mathcal{PT}$ -symmetric dynamical models in complex phase space exhibit strong qualitative similarities.

  20. Vapor-phase heat-transport system

    Energy Technology Data Exchange (ETDEWEB)

    Hedstrom, J.C.

    1983-01-01

    A vapor-phase heat-transport system is being tested in one of the passive test cells at Los Alamos. The system consists of one selective-surface collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by gravity or with a pump. Results from several operating configurations are presented, together with a comparison with other passive systems. A new self-pumping concept is presented.

  1. A Systematic and Numerically Efficient Procedure for Stable Dynamic Model Inversion of LTI Systems

    NARCIS (Netherlands)

    George, K.; Verhaegen, M.; Scherpen, J.M.A.

    1999-01-01

    Output tracking via the novel Stable Dynamic model Inversion (SDI) technique, applicable to non-minimum phase systems, and which naturally takes into account the presence of noise in target time histories, is considered here. We are motivated by the typical need to replicate time signals in the auto

  2. Phase diagram of colloid-rod system

    Science.gov (United States)

    Lai, S. K.; Xiao, Xuhui

    2010-01-01

    The semigrand ensemble theory [H. N. W. Lekkerkerker, W. C. K. Poon, P. N. Pusey, A. Stroobants, and P. B. Warren, Europhys. Lett. 20, 559 (1992)] in conjunction with the fundamental measure density functional theory [V. B. Warshavsky and X. Song, Phys. Rev. E 69, 061113 (2004)] are used to construct the Helmholtz free energy densities of a mixture of uncharged colloidal hard spheres and colloidal rods in its solid and liquid phases. Given these free energy density functions, we apply the free energy density minimization method [G. F. Wang and S. K. Lai, Phys. Rev. E 70, 051402 (2004)] to crosshatch the system's regions of phases in coexistence. The calculated results show that the triangular area bounded by gas-liquid, gas-solid, and liquid-solid coexisting two phases which has been called the coexistence region of gas-liquid-solid corresponds in fact to sets of two phases in coexistence. The phase boundaries which define our calculated coexistence domains compare very well with previous theoretical calculations. The relevance of the phase-diagram domains to three phases in coexistence will be discussed.

  3. Power system identification toolbox: Phase two progress

    Energy Technology Data Exchange (ETDEWEB)

    Trudnowski, D.J.

    1994-08-01

    This report describes current progress on a project funded by the Bonneville Power Administration (BPA) to develop a set of state-of-the-art analysis software (termed the Power System Identification [PSI] Toolbox) for fitting dynamic models to measured data. The project is being conducted as a three-phase effort. The first phase, completed in late 1992, involved investigating the characteristics of the analysis techniques by evaluating existing software and developing guidelines for best use. Phase Two includes extending current software, developing new analysis algorithms and software, and demonstrating and developing applications. The final phase will focus on reorganizing the software into a modular collection of documented computer programs and developing user manuals with instruction and application guidelines. Phase Two is approximately 50% complete; progress to date and a vision for the final product of the PSI Toolbox are described. The needs of the power industry for specialized system identification methods are particularly acute. The industry is currently pushing to operate transmission systems much closer to theoretical limits by using real-time, large-scale control systems to dictate power flows and maintain dynamic stability. Reliably maintaining stability requires extensive system-dynamic modeling and analysis capability, including measurement-based methods. To serve this need, the BPA has developed specialized system-identification computer codes through in-house efforts and university contract research over the last several years. To make full integrated use of the codes, as well as other techniques, the BPA has commissioned Pacific Northwest Laboratory (PNL) to further develop the codes and techniques into the PSI Toolbox.

  4. Fast Offset Laser Phase-Locking System

    Science.gov (United States)

    Shaddock, Daniel; Ware, Brent

    2008-01-01

    Figure 1 shows a simplified block diagram of an improved optoelectronic system for locking the phase of one laser to that of another laser with an adjustable offset frequency specified by the user. In comparison with prior systems, this system exhibits higher performance (including higher stability) and is much easier to use. The system is based on a field-programmable gate array (FPGA) and operates almost entirely digitally; hence, it is easily adaptable to many different systems. The system achieves phase stability of less than a microcycle. It was developed to satisfy the phase-stability requirement for a planned spaceborne gravitational-wave-detecting heterodyne laser interferometer (LISA). The system has potential terrestrial utility in communications, lidar, and other applications. The present system includes a fast phasemeter that is a companion to the microcycle-accurate one described in High-Accuracy, High-Dynamic-Range Phase-Measurement System (NPO-41927), NASA Tech Briefs, Vol. 31, No. 6 (June 2007), page 22. In the present system (as in the previously reported one), beams from the two lasers (here denoted the master and slave lasers) interfere on a photodiode. The heterodyne photodiode output is digitized and fed to the fast phasemeter, which produces suitably conditioned, low-latency analog control signals which lock the phase of the slave laser to that of the master laser. These control signals are used to drive a thermal and a piezoelectric transducer that adjust the frequency and phase of the slave-laser output. The output of the photodiode is a heterodyne signal at the difference between the frequencies of the two lasers. (The difference is currently required to be less than 20 MHz due to the Nyquist limit of the current sampling rate. We foresee few problems in doubling this limit using current equipment.) Within the phasemeter, the photodiode-output signal is digitized to 15 bits at a sampling frequency of 40 MHz by use of the same analog

  5. Future of phased array radar systems

    Science.gov (United States)

    Bassyouni, Ahmed

    2011-12-01

    This paper spots the light on the future progress of phased array radar systems, presenting two innovative examples on the directions of development. The first example starts with the classic radar range equation to develop the topology of what is called a "Mobile Adaptive Digital Array Radar" (MADAR) system. The second example discusses the possibility to achieve what is called "Entangled Photonic Radar" (EPR) system. The EPR quantum range equation is derived and compared to the classic one to compare the performance. Block diagrams and analysis for both proposed systems are presented.

  6. ISDSN Sensor System Phase One Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Gail Heath

    2011-09-01

    This Phase 1 Test Report documents the test activities and results completed for the Idaho National Laboratory (INL) sensor systems that will be deployed in the meso-scale test bed (MSTB) at Florida International University (FIU), as outlined in the ISDSN-MSTB Test Plan. This report captures the sensor system configuration tested; test parameters, testing procedure, any noted changes from the implementation plan, acquired test data sets, and processed results.

  7. Quantum phase transitions in constrained Bose systems

    OpenAIRE

    Bonnes, Lars

    2011-01-01

    This doctoral thesis studies low dimensional quantum systems that can be realized in recent cold atom experiments. From the viewpoint of quantum statistical mechanics, the main emphasis is on the detailed study of the different quantum and thermal phases and their transitions using numerical methods, such as quantum Monte Carlo and the Tensor Network Renormalization Group. The first part of this work deals with a lattice Boson model subject to strong three-body losses. In a quantum-Zeno li...

  8. Phase-Locked Loop Noise Reduction via Phase Detector Implementation for Single-Phase Systems

    Energy Technology Data Exchange (ETDEWEB)

    Thacker, Timothy [Virginia Polytechnic Institute and State University (Virginia Tech); Boroyevich, Dushan [Virginia Polytechnic Institute and State University (Virginia Tech); Burgos, Rolando [ABB; Wang, Fei [ORNL

    2011-01-01

    A crucial component of grid-connected converters is the phase-locked loop (PLL) control subsystem that tracks the grid voltage's frequency and phase angle. Therefore, accurate fast-responding PLLs for control and protection purposes are required to provide these measurements. This paper proposes a novel feedback mechanism for single-phase PLL phase detectors using the estimated phase angle. Ripple noise appearing in the estimated frequency, most commonly the second harmonic under phase-lock conditions, is reduced or eliminated without the use of low-pass filters, which can cause delays to occur and limits the overall performance of the PLL response to dynamic changes in the system. The proposed method has the capability to eliminate the noise ripple entirely and, under extreme line distortion conditions, can reduce the ripple by at least half. Other modifications implemented through frequency feedback are shown to decrease the settling time of the PLL up to 50%. Mathematical analyses with the simulated and experimental results are provided to confirm the validity of the proposed methods.

  9. A novel three-phase UPS system with a single-phase resonant HF link

    OpenAIRE

    Darwish, MK

    2006-01-01

    This paper presents a new three-phase uninterruptible power supply (UPS) system based on a single-phase resonant high frequency (HF) link and a single-phase transformer. The three-phase output voltage is constructed and regulated from a three-phase cycloconverter fed from the constant amplitude, constant frequency link voltage. The generation of a novel switching stategy for the three-phase cycloconverter is presented. The simulation of the proposed system is carried out and verified with exp...

  10. SNR Degradation in Undersampled Phase Measurement Systems

    Directory of Open Access Journals (Sweden)

    David Salido-Monzú

    2016-10-01

    Full Text Available A wide range of measuring applications rely on phase estimation on sinusoidal signals. These systems, where the estimation is mainly implemented in the digital domain, can generally benefit from the use of undersampling to reduce the digitizer and subsequent digital processing requirements. This may be crucial when the application characteristics necessarily imply a simple and inexpensive sensor. However, practical limitations related to the phase stability of the band-pass filter prior digitization establish restrictions to the reduction of noise bandwidth. Due to this, the undersampling intensity is practically defined by noise aliasing, taking into account the amount of signal-to-noise ratio (SNR reduction caused by it considering the application accuracy requirements. This work analyzes the relationship between undersampling frequency and SNR reduction, conditioned by the stability requirements of the filter that defines the noise bandwidth before digitization. The effect of undersampling is quantified in a practical situation where phase differences are measured by in-phase and quadrature (I/Q demodulation for an infrared ranging application.

  11. PT phase transition in multidimensional quantum systems

    CERN Document Server

    Bender, Carl M

    2012-01-01

    Non-Hermitian PT-symmetric quantum-mechanical Hamiltonians generally exhibit a phase transition that separates two parametric regions, (i) a region of unbroken PT symmetry in which the eigenvalues are all real, and (ii) a region of broken PT symmetry in which some of the eigenvalues are complex. This transition has recently been observed experimentally in a variety of physical systems. Until now, theoretical studies of the PT phase transition have generally been limited to one-dimensional models. Here, four nontrivial coupled PT-symmetric Hamiltonians, $H=p^2/2+x^2/2+q^2/2+y^2/2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2+igx^2y$, $H=p^2/2+x^2/2+q^2/2+y^2/2+r^2/2+z^2/2+igxyz$, and $H=p^2/2+x^2/2+q^2/2+y^2+r^2/2+3z^2/2+igxyz$ are examined. Based on extensive numerical studies, this paper conjectures that all four models exhibit a phase transition. The transitions are found to occur at $g\\approx 0.1$, $g\\approx 0.04$, $g\\approx 0.1$, and $g\\approx 0.05$. These results suggest that the PT phase transition is a robust phen...

  12. New photosensitive systems for volume phase holography

    Science.gov (United States)

    Bianco, Andrea; Colella, Letizia; Galli, Paola; Zanutta, Alessio; Bertarelli, Chiara

    2017-05-01

    Volume phase holographic elements are becoming attractive thanks to the large efficiency and good optical quality. They are based on photosensitive materials where a modulation of the refractive index is induced. In this paper, we highlight the strategies to obtain a change in the refractive index in a dielectric material, namely a change in the material density and/or in the molecular polarizability. Moreover, we show the results achieved for materials that undergo the photo-Fries reaction as function of the molecular structure and the illumination conditions. We also report the results on a system based on the diazo Meldrum's acid where volatile molecules are produced upon light exposure.

  13. Phase transitions in open quantum systems

    CERN Document Server

    Jung, C; Rotter, I

    1999-01-01

    We consider the behaviour of open quantum systems in dependence on the coupling to one decay channel by introducing the coupling parameter $\\alpha$ being proportional to the average degree of overlapping. Under critical conditions, a reorganization of the spectrum takes place which creates a bifurcation of the time scales with respect to the lifetimes of the resonance states. We derive analytically the conditions under which the reorganization process can be understood as a second-order phase transition and illustrate our results by numerical investigations. The conditions are fulfilled e.g. for a picket fence with equal coupling of the states to the continuum. Energy dependencies within the system are included. We consider also the generic case of an unfolded Gaussian Orthogonal Ensemble. In all these cases, the reorganization of the spectrum occurs at the critical value $\\alpha_{crit}$ of the control parameter globally over the whole energy range of the spectrum. All states act cooperatively.

  14. A Survey of Phase Change Memory Systems

    Institute of Scientific and Technical Information of China (English)

    夏飞; 蒋德钧; 熊劲; 孙凝晖

    2015-01-01

    As the scaling of applications increases, the demand of main memory capacity increases in order to serve large working set. It is difficult for DRAM (dynamic random access memory) based memory system to satisfy the memory capacity requirement due to its limited scalability and high energy consumption. Compared to DRAM, PCM (phase change memory) has better scalability, lower energy leakage, and non-volatility. PCM memory systems have become a hot topic of academic and industrial research. However, PCM technology has the following three drawbacks: long write latency, limited write endurance, and high write energy, which raises challenges to its adoption in practice. This paper surveys architectural research work to optimize PCM memory systems. First, this paper introduces the background of PCM. Then, it surveys research efforts on PCM memory systems in performance optimization, lifetime improving, and energy saving in detail, respectively. This paper also compares and summarizes these techniques from multiple dimensions. Finally, it concludes these optimization techniques and discusses possible research directions of PCM memory systems in future.

  15. System response in passively phased fiber amplifier arrays

    Science.gov (United States)

    Shakir, Sami A.; Culver, Bill; Nelson, Burke; Starcher, Yuji; Bates, George M.; Hedrick, Jerry W., Jr.

    2008-08-01

    System temporal response in passively phased fiber amplifier arrays dictates how fast a passively phased system can correct for phase fluctuations due to thermal and mechanical effects. The system response time was measured by employing a variable-speed mechanical chopper in the feedback loop of a passively phased system then measuring the on-axis output intensity of the system as a function of time. Observed relaxation oscillations are compared to theory. The system response time was measured to be about 20 μsec. We also find that passive phasing improved the system's beam stability and extraction efficiency.

  16. Phase-field simulation of liquid phase migration in the WC-Co system during liquid phase sintering

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kaiming; Zhang, Lijun; Du, Yong [Central South Univ., Changsha (China). State Key Lab. of Powder Metallurgy; Schwarze, Christian; Steinbach, Ingo [Bochum Univ. (Germany). Interdisciplinary Centre for Advanced Materials Simulation

    2016-04-15

    Liquid phase sintering is a process for forming high performance, multiple-phase components from powders. The process includes very complex interactions between various mass transportation phenomena, among which the liquid phase migration represents an important one in the aspect of forming a gradient structure in cemented carbide. In the present work, phase-field simulation of the liquid phase migration phenomenon during liquid phase sintering is performed in the WC-Co based cemented carbide. The simulation results are analyzed and compared with the experimentally determined key factors of microstructural evolution, such as contiguity and liquid phase migration rate. The diffusion-controlled solution-precipitation mechanism of the liquid phase migration process in the cemented carbide system is confirmed from the current simulation result, which provides deeper understanding of the microstructural evolution during the liquid phase migration process. These simulations can offer guidance in preventing the liquid phase migration process during liquid phase sintering of cellular cemented carbide.

  17. VARIANCE OF NONLINEAR PHASE NOISE IN FIBER-OPTIC SYSTEM

    OpenAIRE

    RANJU KANWAR; SAMEKSHA BHASKAR

    2013-01-01

    In communication system, the noise process must be known, in order to compute the system performance. The nonlinear effects act as strong perturbation in long- haul system. This perturbation effects the signal, when interact with amplitude noise, and results in random motion of the phase of the signal. Based on the perturbation theory, the variance of nonlinear phase noise contaminated by both self- and cross-phase modulation, is derived analytically for phase-shift- keying system. Through th...

  18. Phase Noise Influence in Optical OFDM Systems employing RF Pilot Tone for Phase Noise Cancellation

    OpenAIRE

    Jacobsen, Gunnar; Kazovsky, Leonid G.; Xu, TianHua; Popov, Sergei; Li, Jie; Zhang, Yimo; Friberg, Ari T.

    2016-01-01

    For coherent and direct-detection Orthogonal Frequency Division Multiplexed (OFDM) systems employing radio frequency (RF) pilot tone phase noise cancellation the influence of laser phase noise is evaluated. Novel analytical results for the common phase error and for the (modulation dependent) inter carrier interference are evaluated based upon Gaussian statistics for the laser phase noise. In the evaluation it is accounted for that the laser phase noise is filtered in the correlation signal d...

  19. Low Cost Phased Array Antenna System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — JEM Engineering proved the technical feasibility of the FlexScan array?a very low-cost, highly-efficient, wideband phased array antenna?in Phase I, and stands ready...

  20. Control of a perturbed under-actuated mechanical system

    KAUST Repository

    Zayane, Chadia

    2015-11-05

    In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed high order sliding mode control architecture including a controller and differentiator allows to track accurately the predefined trajectory and to stabilize the internal dynamics. The robustness of the proposed approach is illustrated through different perturbation and output noise configurations.

  1. Re-entrant phase behavior for systems with competition between phase separation and self-assembly.

    Science.gov (United States)

    Reinhardt, Aleks; Williamson, Alexander J; Doye, Jonathan P K; Carrete, Jesús; Varela, Luis M; Louis, Ard A

    2011-03-14

    In patchy particle systems where there is a competition between the self-assembly of finite clusters and liquid-vapor phase separation, re-entrant phase behavior can be observed, with the system passing from a monomeric vapor phase to a region of liquid-vapor phase coexistence and then to a vapor phase of clusters as the temperature is decreased at constant density. Here, we present a classical statistical mechanical approach to the determination of the complete phase diagram of such a system. We model the system as a van der Waals fluid, but one where the monomers can assemble into monodisperse clusters that have no attractive interactions with any of the other species. The resulting phase diagrams show a clear region of re-entrance. However, for the most physically reasonable parameter values of the model, this behavior is restricted to a certain range of density, with phase separation still persisting at high densities.

  2. Phase Space Cell in Nonextensive Classical Systems

    Directory of Open Access Journals (Sweden)

    Piero Quarati

    2003-06-01

    Full Text Available Abstract: We calculate the phase space volume Ω occupied by a nonextensive system of N classical particles described by an equilibrium (or steady-state, or long-term stationary state of a nonequilibrium system distribution function, which slightly deviates from Maxwell-Boltzmann (MB distribution in the high energy tail. We explicitly require that the number of accessible microstates does not change respect to the extensive MB case. We also derive, within a classical scheme, an analytical expression of the elementary cell that can be seen as a macrocell, different from the third power of Planck constant. Thermodynamic quantities like entropy, chemical potential and free energy of a classical ideal gas, depending on elementary cell, are evaluated. Considering the fractional deviation from MB distribution we can deduce a physical meaning of the nonextensive parameter q of the Tsallis nonextensive thermostatistics in terms of particle correlation functions (valid at least in the case, discussed in this work, of small deviations from MB standard case.

  3. Integrable system on phase space with nonplanar metrics

    CERN Document Server

    Bogdanov, E I

    2001-01-01

    The problem on the integrability of the evolution system on the phase spaces with the nonplanar metrics is studied. It is shown that in the case, when the phase space is a sphere, the system Hamiltonians are generated under the action of the Poisson operators on the variations of the phase space geodesic lines and the problem on the evolution system integrability is reduced to the task on the integrability of the repers motion equations on the phase space. The bihamiltonian representation of the evaluation systems is connected with the differential-geometric properties of the phase space

  4. Windowed phase unwrapping using a first-order dynamic system following iso-phase contours.

    Science.gov (United States)

    Estrada, Julio C; Vargas, Javier; Flores-Moreno, J Mauricio; Quiroga, J Antonio

    2012-11-01

    In this work, we show a windowed phase-unwrapping technique that uses a first-order dynamic system and scans the phase following its iso-phase contours. In previous works, we have shown that low-pass first-order dynamic systems are very robust and useful in phase-unwrapping problems. However, it is well known that all phase-unwrapping methods have a minimum signal-to-noise ratio that they tolerate. This paper shows that scanning the phase within local windows and using a path following strategy, the first-order unwrapping method increases its tolerance to noise. In this way, using the improved approach, we can unwrap phase maps where the basic dynamic phase-unwrapping system fails. Tests and results are given, as well as the source code in order to show the performance of the proposed method.

  5. Phase behaviour of transfer functions in vibrating systems

    DEFF Research Database (Denmark)

    Zhu, Jianyuan; Ohlrich, Mogens

    1998-01-01

    This paper investigates the applicabilities of pole-zero models and wave propagation theory in estimating the phase characteristics of vibrating systems. The measured phase spectra are compared with the estimated reverberant phase limit and wave propagation phase. The relations between transfer...... on frequency in this band, but from the transition frequency and onwards the phase increases only with the square root of frequency. This behaviour is characteristic for free propagating waves....

  6. System For Characterizing Three-Phase Brushless dc Motors

    Science.gov (United States)

    Howard, David E.; Smith, Dennis A.

    1996-01-01

    System of electronic hardware and software developed to automate measurements and calculations needed to characterize electromechanical performances of three-phase brushless dc motors, associated shaft-angle sensors needed for commutation, and associated brushless tachometers. System quickly takes measurements on all three phases of motor, tachometer, and shaft-angle sensor simultaneously and processes measurements into performance data. Also useful in development and testing of motors with not only three phases but also two, four, or more phases.

  7. Adaptive optimisation of a generalised phase contrast beam shaping system

    Science.gov (United States)

    Kenny, F.; Choi, F. S.; Glückstad, J.; Booth, M. J.

    2015-05-01

    The generalised phase contrast (GPC) method provides versatile and efficient light shaping for a range of applications. We have implemented a generalised phase contrast system that used two passes on a single spatial light modulator (SLM). Both the pupil phase distribution and the phase contrast filter were generated by the SLM. This provided extra flexibility and control over the parameters of the system including the phase step magnitude, shape, radius and position of the filter. A feedback method for the on-line optimisation of these properties was also developed. Using feedback from images of the generated light field, it was possible to dynamically adjust the phase filter parameters to provide optimum contrast.

  8. Phase transitions in fluids and biological systems

    Science.gov (United States)

    Sipos, Maksim

    metric to 16S rRNA metagenomic studies of 6 vertebrate gastrointestinal microbiomes and find that they assembled through a highly non-neutral process. I then consider a phase transition that may occur in nutrient-poor environments such as ocean surface waters. In these systems, I find that the experimentally observed genome streamlining, specialization and opportunism may well be generic statistical phenomena.

  9. Performance limitations for networked control systems with plant uncertainty

    Science.gov (United States)

    Chi, Ming; Guan, Zhi-Hong; Cheng, Xin-Ming; Yuan, Fu-Shun

    2016-04-01

    There has recently been significant interest in performance study for networked control systems with communication constraints. But the existing work mainly assumes that the plant has an exact model. The goal of this paper is to investigate the optimal tracking performance for networked control system in the presence of plant uncertainty. The plant under consideration is assumed to be non-minimum phase and unstable, while the two-parameter controller is employed and the integral square criterion is adopted to measure the tracking error. And we formulate the uncertainty by utilising stochastic embedding. The explicit expression of the tracking performance has been obtained. The results show that the network communication noise and the model uncertainty, as well as the unstable poles and non-minimum phase zeros, can worsen the tracking performance.

  10. Systems and Methods for Parameter Dependent Riccati Equation Approaches to Adaptive Control

    Science.gov (United States)

    Kim, Kilsoo (Inventor); Yucelen, Tansel (Inventor); Calise, Anthony J. (Inventor)

    2015-01-01

    Systems and methods for adaptive control are disclosed. The systems and methods can control uncertain dynamic systems. The control system can comprise a controller that employs a parameter dependent Riccati equation. The controller can produce a response that causes the state of the system to remain bounded. The control system can control both minimum phase and non-minimum phase systems. The control system can augment an existing, non-adaptive control design without modifying the gains employed in that design. The control system can also avoid the use of high gains in both the observer design and the adaptive control law.

  11. Low Cost Phased Array Antenna System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A program is proposed to research the applicability of a unique phased array technology, dubbed FlexScan, to S-band and Ku-band communications links between...

  12. Nonlinear phase noise in coherent optical OFDM transmission systems.

    Science.gov (United States)

    Zhu, Xianming; Kumar, Shiva

    2010-03-29

    We derive an analytical formula to estimate the variance of nonlinear phase noise caused by the interaction of amplified spontaneous emission (ASE) noise with fiber nonlinearity such as self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM) in coherent orthogonal frequency division multiplexing (OFDM) systems. The analytical results agree very well with numerical simulations, enabling the study of the nonlinear penalties in long-haul coherent OFDM systems without extensive numerical simulation. Our results show that the nonlinear phase noise induced by FWM is significantly larger than that induced by SPM and XPM, which is in contrast to traditional WDM systems where ASE-FWM interaction is negligible in quasi-linear systems. We also found that fiber chromatic dispersion can reduce the nonlinear phase noise. The variance of the total phase noise increases linearly with the bit rate, and does not depend significantly on the number of subcarriers for systems with moderate fiber chromatic dispersion.

  13. Phase-space networks of geometrically frustrated systems

    Science.gov (United States)

    Han, Yilong

    2009-11-01

    We illustrate a network approach to the phase-space study by using two geometrical frustration models: antiferromagnet on triangular lattice and square ice. Their highly degenerated ground states are mapped as discrete networks such that the quantitative network analysis can be applied to phase-space studies. The resulting phase spaces share some comon features and establish a class of complex networks with unique Gaussian spectral densities. Although phase-space networks are heterogeneously connected, the systems are still ergodic due to the random Poisson processes. This network approach can be generalized to phase spaces of some other complex systems.

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

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni

    2011-01-01

    In this paper, a novel single phase hybrid switched reluctance motor(SRM) drive system is proposed. It integrated a single phase hybrid SRM and a novel single phase boost converter. This motor can reduce the number of phase switch. And the permanent magnet which is used in the motor can improve t...... SRM reduce the negative torque before zero-crossing point of torque curve, and build desired phase current to generate more power. Some experimental results are done to verify the performance of proposed hybrid SRM drive system....

  15. Integrated thermal treatment system sudy: Phase 2, Results

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Quapp, W.J.

    1995-08-01

    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study, the results of which have been published as an interim report, examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 2 systems. The assumptions and methods were the same as for the Phase 1 study. The quantities, and physical and chemical compositions, of the input waste used in he Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr).

  16. Active phase compensation of quantum key distribution system

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; HAN ZhengFu; MO XiaoFan; XU FangXing; WEI Guo; GUO GuangCan

    2008-01-01

    Quantum key distribution (QKD) system must be robust enough in practical communication. Besides birefringence of fiber, system performance is notably affected by phase drift. The Faraday-Michelson QKD system can auto-compensate the birefringence of fiber, but phase shift is still a serious problem in its practical operation. In this paper, the major reason of phase drift and its effect on Faraday-Michel-son QKD system is analyzed and an effective active phase compensation scheme is proposed. By this means, we demonstrate a quantum key distribution system which can stably run over 37-km fiber in practical working condition with the long-time averaged quantum bit error rate of 1.59% and the stan-dard derivation of 0.46%. This result shows that the active phase compensation scheme is suitable to be used in practical QKD systems based on double asymmetric interferometers without additional de-vices and thermal controller.

  17. Quantum phase transition and entanglement in Li atom system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By use of the exact diagonalization method, the quantum phase transition and en- tanglement in a 6-Li atom system are studied. It is found that entanglement appears before the quantum phase transition and disappears after it in this exactly solvable quantum system. The present results show that the von Neumann entropy, as a measure of entanglement, may reveal the quantum phase transition in this model.

  18. Load frequency stabilization by coordinated control of Thyristor Controlled Phase Shifters and superconducting magnetic energy storage for three types of interconnected two-area power systems

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Praghnesh [Department of Electrical Engineering, Charotar Institute of Technology, Changa 388 421, Gujarat (India); Ghoshal, S.P. [Department of Electrical Engineering, National Institute of Technology, Durgapur 713 209, West Bengal (India); Roy, Ranjit [Department of Electrical Engineering, S.V. National Institute of Technology, Surat 395 007, Gujarat (India)

    2010-12-15

    In this paper, automatic generation control with interconnected two-area multi-unit all-hydro power system and two more test systems as all-thermal and thermal-hydro mixed haves been investigated. The transfer function of hydro turbine having non-minimum phase characteristics makes it different from the steam turbine. Upon application of small load perturbation to such all-hydro system, the frequency is severely disturbed and the system eventually becomes unstable. To stabilize the system for such load disturbance, comparative transient performance of two cases as (a) Thyristor Controlled Phase Shifter (TCPS) installed in series with the tie-line in coordination with Superconducting Magnetic Energy Storage (SMES) and (b) SMES located at each terminal of both areas are analyzed. It is observed that the case (b) i.e. SMES located at each terminal of both areas suppresses the frequency oscillations more effectively in integral controller assisted AGC of two-area multi-unit all-hydro system and the other two systems as well. In addition, the effectiveness of proposed frequency stabilizers is guaranteed by analyzing the transient responses of the system with different system parameters, various load patterns and in the event of temporary and permanent tie-line outage. Gains of the integral controller in AGC loop and parameters of TCPS and SMES are optimized with the help of a relatively novel particle swarm optimization, developed by the authors, called as craziness-based particle swarm optimization (CRPSO). The optimizing performance has been compared to that of real-coded genetic algorithm (RGA) to establish its superiority. (author)

  19. A new atmospheric aerosol phase equilibrium model (UHAERO: organic systems

    Directory of Open Access Journals (Sweden)

    N. R. Amundson

    2007-09-01

    Full Text Available In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.

  20. A new atmospheric aerosol phase equilibrium model (UHAERO: organic systems

    Directory of Open Access Journals (Sweden)

    N. R. Amundson

    2007-06-01

    Full Text Available In atmospheric aerosols, water and volatile inorganic and organic species are distributed between the gas and aerosol phases in accordance with thermodynamic equilibrium. Within an atmospheric particle, liquid and solid phases can exist at equilibrium. Models exist for computation of phase equilibria for inorganic/water mixtures typical of atmospheric aerosols; when organic species are present, the phase equilibrium problem is complicated by organic/water interactions as well as the potentially large number of organic species. We present here an extension of the UHAERO inorganic thermodynamic model (Amundson et al., 2006c to organic/water systems. Phase diagrams for a number of model organic/water systems characteristic of both primary and secondary organic aerosols are computed. Also calculated are inorganic/organic/water phase diagrams that show the effect of organics on inorganic deliquescence behavior. The effect of the choice of activity coefficient model for organics on the computed phase equilibria is explored.

  1. Phase equilibria in the Ni-Co-Ga alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Ducher, R. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579 (Japan); Kainuma, R. [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)], E-mail: kainuma@tagen.tohoku.ac.jp; Ishida, K. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579 (Japan)

    2008-10-20

    Phase equilibria among the {alpha} (A1), {alpha}' (L1{sub 2}), {beta} (B2), {delta} (Ni{sub 5}Ga{sub 3}) and {epsilon} (Ni{sub 13}Ga{sub 9}) phases at elevated temperatures and the existing composition region of the martensite phase at room temperature in the Ni-Co side of the Ni-Co-Ga system were examined by electron probe microanalysis (EPMA) using diffusion triples which were fabricated by two-step diffusion coupling. It was confirmed that single-phase regions of the {alpha}, {alpha}' and {beta} phases at 700 and 1000 deg. C exist in a wide composition range parallel to Ni-Co section and that the existing region of the martensite phase at room temperature is also located over a wide range in the {beta} phase along the {beta} + {alpha} (or {alpha}') two-phase region.

  2. Phase diagram for a nano-yttria-stabilized zirconia system

    DEFF Research Database (Denmark)

    Asadikiya, Mohammad; Sabarou, Hooman; Chen, Ming;

    2016-01-01

    Due to the attractive properties of nanoparticles because of their effective surface area, they have been studied widely. Nano-yttria-stabilized zirconia (n-YSZ) is a ceramic which has been scrutinized extensively in past years. Because of the different stability behavior of n-YSZ in comparison...... with bulk YSZ, a new phase diagram is needed for the n-YSZ system in order to identify stable phases under various conditions. In this study, a phase diagram for the n-YSZ system was provided to determine phase stability ranges at room temperature with respect to particle size and composition....... By applying the CALPHAD approach, a 3-D phase diagram for the n-YSZ system was established in which the stability range of each individual phase can be predicted based on the particle size, composition, and temperature....

  3. Ternary phase diagram calculations of pentaerythritol-pentaglycerine-neopentylglycol system

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, A.; Talekar, A. [Chemical and Materials Engineering Department (MS388), University of Nevada, Reno, NV 89557 (United States); Chandra, D., E-mail: dchandra@unr.edu [Chemical and Materials Engineering Department (MS388), University of Nevada, Reno, NV 89557 (United States); Chien, W.-M. [Chemical and Materials Engineering Department (MS388), University of Nevada, Reno, NV 89557 (United States)

    2012-05-10

    Highlights: Black-Right-Pointing-Pointer Ternary phase diagrams of polyalcohols are developed using the CALPHAD method. Black-Right-Pointing-Pointer These ternary phase diagrams are thermodynamically calculated for the first time. Black-Right-Pointing-Pointer Orientational disorder is observed in the high temperature (energy storage) phase. Black-Right-Pointing-Pointer Polyalcohols are potential thermal energy storage materials. - Abstract: The pentaerythritol (PE)-pentaglycerine (PG)-neopentylglycol (NPG) ternary system has been thermodynamically assessed using the CALPHAD method and Thermo-Calc software. The PE-PG, PG-NPG, PE-NPG binary systems have also been calculated using CALPHAD on the basis of reported binary experimental data. The solution phases are modeled as substitutional solutions, in which the excess Gibbs energies are expressed by the Redlich-Kister-Muggianu polynomial. The PE-NPG binary phase diagram was modeled using Henrian solution model, and the liquid phase was assumed ideal. The PG-NPG system was optimized using regular and sub-regular solution models and show invariant equilibria at 298 K. The PE-NPG binary system was calculated from room temperature to the liquid phase temperatures. The modeled phase diagrams and the experimental data are in good agreement. A set of self consistent thermodynamic parameters formulating the Gibbs energies of various phases in the PE-PG-NPG ternary system are obtained in the present work. Thermodynamic properties, several vertical and isopleth sections have been calculated and are in good agreement with experimental data.

  4. Phase Diagrams for Systems Containing Hyperbranched Polymers

    Directory of Open Access Journals (Sweden)

    Tim Zeiner

    2012-01-01

    Full Text Available Hyperbranched polymers show an outstanding potential for applications ranging from chemistry over nanotechnology to pharmacy. In order to take advantage of this potential, the underlying phase behaviour must be known. From the thermodynamic point of view, the modelling of these phase diagrams is quite challenging, because the thermodynamic properties depend on the architecture of the hyperbranched polymer as well as on the number and kind of present functional end groups. The influence of architecture can be taken into account via the lattice cluster theory (LCT as an extension of the well-known Flory–Huggins theory. Whereas the Flory–Huggins theory is limited to linear polymer chains, the LCT can be applied to an arbitrary chain architecture. The number and the kind of functional groups can be handled via the Wertheim perturbation theory, applicable for directed forces between the functional groups and the surrounding solvent molecules. The combination of the LCT and the Wertheim theory can be established for the modelling or even prediction of the liquid-liquid equilibria (LLE of polymer solutions in a single solvent or in a solvent mixture or polymer blends, where the polymer can have an arbitrary structure. The applied theory predicts large demixing regions for mixtures of linear polymers and hyperbranched polymers, as well as for mixtures made from two hyperbranched polymers. The introduction of empty lattice sites permits the theoretical investigation of pressure effects on phase behaviour. The calculated phase diagrams were compared with own experimental data or to experimental data taken from literature.

  5. Phase Diagram Modelling: Nickel - Aluminum - Chromium System

    Science.gov (United States)

    1998-04-01

    conducted by Kaufman and co-workers and their lattice stabilities have formed the basis of phase diagram calculations to the present day.1 In...mol ( 0.74827 Ni + 0.73305E-01 Cr + 0.83609E-02 Al ( 1200.00 C, 1.0000 <—s -.Molten alloy <—s <—s) atm, L- NiCrAl , a=0.82994 ) 0.00000

  6. Retinal Drug Delivery System, Phase I

    Science.gov (United States)

    1997-06-01

    macular degeneration (AMD) and diabetic retinopathy. Intraocular injection can place the drug directly into the vitreous cavity but is not recommended...drugs for treatment of other ocular diseases such as retinal tumors, diabetic retinopathy, age related macular degeneration and cytomegalovirus...with the changes in mobile phase as indicated in each section. Data was collected for 10 min and the peak area was analyzed using the standard

  7. Demonstration Advanced Avionics System (DAAS), Phase 1

    Science.gov (United States)

    Bailey, A. J.; Bailey, D. G.; Gaabo, R. J.; Lahn, T. G.; Larson, J. C.; Peterson, E. M.; Schuck, J. W.; Rodgers, D. L.; Wroblewski, K. A.

    1981-01-01

    Demonstration advanced anionics system (DAAS) function description, hardware description, operational evaluation, and failure mode and effects analysis (FMEA) are provided. Projected advanced avionics system (PAAS) description, reliability analysis, cost analysis, maintainability analysis, and modularity analysis are discussed.

  8. Phase Noise Influence in Optical OFDM Systems employing RF Pilot Tone for Phase Noise Cancellation

    Science.gov (United States)

    Jacobsen, Gunnar; Kazovsky, Leonid G.; Xu, Tianhua; Popov, Sergei; Li, Jie; Zhang, Yima; Friberg, Ari T.

    2011-06-01

    For coherent and direct-detection Orthogonal Frequency Division Multiplexed (OFDM) systems employing radio frequency (RF) pilot tone phase noise cancellation the influence of laser phase noise is evaluated. Novel analytical results for the common phase error and for the (modulation dependent) inter carrier interference are evaluated based upon Gaussian statistics for the laser phase noise. In the evaluation it is accounted for that the laser phase noise is filtered in the correlation signal detection. Numerical results are presented for OFDM systems with 4 and 16 PSK modulation, 200 OFDM bins and baud rate of 1 GS/s. It is found that about 225 km transmission is feasible for the coherent 4PSK-OFDM system over normal (G.652) fiber.

  9. Phase Noise Influence in Optical OFDM Systems employing RF Pilot Tone for Phase Noise Cancellation

    CERN Document Server

    Jacobsen, Gunnar; Xu, Tianhua; Popov, Sergei; Li, Jie; Zhang, Yimo; Friberg, Ari T

    2016-01-01

    For coherent and direct-detection Orthogonal Frequency Division Multiplexed (OFDM) systems employing radio frequency (RF) pilot tone phase noise cancellation the influence of laser phase noise is evaluated. Novel analytical results for the common phase error and for the (modulation dependent) inter carrier interference are evaluated based upon Gaussian statistics for the laser phase noise. In the evaluation it is accounted for that the laser phase noise is filtered in the correlation signal detection. Numerical results are presented for OFDM systems with 4 and 16 PSK modulation, 200 OFDM bins and baud rate of 1 GS/s. It is found that about 225 km transmission is feasible for the coherent 4PSK-OFDM system over normal (G.652) fiber.

  10. Simulation model for a seven-phase BLDCM drive system

    Science.gov (United States)

    Park, Sang-Hoon; Lee, Won-Cheol; Lee, Jung-Hyo; Yu, Jae-Sung; Kim, Gyu-Sik; Won, Chung-Yuen

    2007-12-01

    BLDC motors have many advantages over brushed DC motors and induction motors. So, BLDC motors extend their application to many industrial fields. In this paper, the digital simulation and modeling of a 7-phase brushless DC motor have been presented. The 14-switch inverter and a 7-phase brushless DC motor drive system are simulated using hysteresis current controller and logic of switching pattern with the Boolean¡s function. Through some simulations, we found that our modeling and analysis of a 7-phase BLDCM with PWM inverter would be helpful for the further studies of the multi-phase BLDCM drive systems.

  11. Argus phase II optical data collection system

    Science.gov (United States)

    Wasson, Wayne E.

    1996-11-01

    The Argus aircraft is a highly modified NC-135E fitted with an infrared and ultraviolet-visible sensor suite for radiometric and spectral data collection. Each suite is operated independently with its own separate gimbal for precision pointing, telescope, and relay optics. The system includes a silica window for the ultraviolet-visible, and a zinc selenide window for the infrared. The entire system was developed and fabricated in-house at the Phillips Laboratory. All sensors are calibrated as a system onboard the aircraft through a unique facility called the aircraft optical calibration facility. The data is all recorded digitally, and can be transferred to secure data reduction facilities via optical fiber. The system is modular, in that the ultraviolet-visible and infrared benches can be separated, or the entire system can be quickly removed to allow for the introduction of other sensor suites or systems. The gimbals and telescopes can be used independently of the rest of the system. The aircraft is also fitted with an anemometry system, which can be operated independently of the sensor systems. This aircraft is capable of many types of missions, and will soon be fitted with a LIDAR system for remote sensing. The philosophy in building the system is to make it capable of quick changes during mission.

  12. 4F-based optical phase imaging system

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to 4F-based optical phase imaging system and in particular to reconstructing quantitative phase information of an object when using such systems. The invention applies a two-dimensional, complex spatial light modulator (SLM) to impress a complex spatial synthesized modulation...... in addition to the complex spatial modulation impressed by the object. This SLM is arranged so that the synthesized modulation is superimposed with the object modulation and is thus placed at an input plane to the phase imaging system. By evaluating output images from the phase imaging system, the synthesized...... modulation is selected to optimize parameters in the output image which improves the reconstruction of qualitative and quantitative object phase information from the resulting output images....

  13. Differential phase contrast X-ray imaging system and components

    Science.gov (United States)

    Stutman, Daniel; Finkenthal, Michael

    2014-07-01

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  14. Differential phase contrast X-ray imaging system and components

    Energy Technology Data Exchange (ETDEWEB)

    Stutman, Daniel; Finkenthal, Michael

    2017-01-31

    A differential phase contrast X-ray imaging system includes an X-ray illumination system, a beam splitter arranged in an optical path of the X-ray illumination system, and a detection system arranged in an optical path to detect X-rays after passing through the beam splitter.

  15. AC system stabilization via phase shift transformer with thyristor commutation

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Jose Carlos de; Guimaraes, Geraldo Caixeta; Moraes, Adelio Jose [Uberlandia Univ., MG (Brazil); Abreu, Jose Policarpo G. de [Escola Federal de Engenharia de Itajuba, MG (Brazil); Oliveira, Edimar Jose de [Juiz de Fora Univ., MG (Brazil)

    1994-12-31

    This article aims to present initially the constructive and operative forms of a phase-shift autotransformer which provides both magnitude and phase angle change through thyristor commutation, including a technic to reduce the number of thyristors. Following, it is proposed a control system to make such equipment an efficient AC system stabilizing tool. It is presented some simulation results to show the operation of this transformer in an electrical system. (author) 3 refs., 11 figs., 3 tabs.

  16. Flexible Manufacturing System--The procurement phase

    Energy Technology Data Exchange (ETDEWEB)

    Van Cleave, R.A.

    1992-02-01

    A method has been developed for procuring a Flexible Manufacturing System (FMS). The method includes preparation of a functional specification that defines equipment and system requirements; development of relationships between the potential suppliers and purchasers; proposal evaluation and selection in a competitive bid environment; and a technique to minimize misunderstandings between buyer requirements and supplier offerings. Methods established during this development effort have permitted successful procurement of a multimillion-dollar FMS. Techniques used will be helpful to procurement of other systems.

  17. Turbo Receiver Design for Phase Noise Mitigation in OFDM Systems

    CERN Document Server

    Sridharan, Gokul

    2010-01-01

    This paper addresses the issue of phase noise in OFDM systems. Phase noise (PHN) is a transceiver impairment resulting from the non-idealities of the local oscillator. We present a case for designing a turbo receiver for systems corrupted by phase noise by taking a closer look at the effects of the common phase error (CPE). Using an approximate probabilistic framework called variational inference (VI), we develop a soft-in soft-out (SISO) algorithm that generates posterior bit-level soft estimates while taking into account the effect of phase noise. The algorithm also provides an estimate of the phase noise sequence. Using this SISO algorithm, a turbo receiver is designed by passing soft information between the SISO detector and an outer forward error correcting (FEC) decoder that uses a soft decoding algorithm. It is shown that the turbo receiver achieves close to optimal performance.

  18. Measuring the Aharonov-Anandan phase in multiport photonic systems.

    Science.gov (United States)

    Wang, Kai; Weimann, Steffen; Nolte, Stefan; Perez-Leija, Armando; Szameit, Alexander

    2016-04-15

    Beyond the adiabatic limit, the Aharonov-Anandan phase is a generalized description of Berry's phase. In this regime, systems with time-independent Hamiltonians may also acquire observable geometric phases. Here we report on a measurement of the Aharonov-Anandan phase in photonics. Different from previous optical experiments on geometric phases, the implementation is based on light modes confined in evanescently coupled waveguides rather than polarization-like systems, thereby physical models in more than two-dimensional Hilbert spaces are achievable. In a tailored photonic lattice, we realize time-independent quantum-driven harmonic oscillators initially prepared in the vacuum state and achieve a measurement of the Aharonov-Anandan phase via integrated interferometry.

  19. Noise robust linear dynamic system for phase unwrapping and smoothing.

    Science.gov (United States)

    Estrada, Julio C; Servin, Manuel; Quiroga, Juan A

    2011-03-14

    Phase unwrapping techniques remove the modulus ambiguities of wrapped phase maps. The present work shows a first-order feedback system for phase unwrapping and smoothing. This system is a fast sequential unwrapping system which also allows filtering some noise because in deed it is an Infinite Impulse Response (IIR) low-pass filter. In other words, our system is capable of low-pass filtering the wrapped phase as the unwrapping process proceeds. We demonstrate the temporal stability of this unwrapping feedback system, as well as its low-pass filtering capabilities. Our system even outperforms the most common and used unwrapping methods that we tested, such as the Flynn's method, the Goldstain's method, and the Ghiglia least-squares method (weighted or unweighted). The comparisons with these methods shows that our system filters-out some noise while preserving the dynamic range of the phase-data. Its application areas may cover: optical metrology, synthetic aperture radar systems, magnetic resonance, and those imaging systems where information is obtained as a demodulated wrapped phase map.

  20. Phased Antenna Array for Global Navigation Satellite System Signals

    Science.gov (United States)

    Turbiner, Dmitry (Inventor)

    2015-01-01

    Systems and methods for phased array antennas are described. Supports for phased array antennas can be constructed by 3D printing. The array elements and combiner network can be constructed by conducting wire. Different parameters of the antenna, like the gain and directivity, can be controlled by selection of the appropriate design, and by electrical steering. Phased array antennas may be used for radio occultation measurements.

  1. SPS phase control system performance via analytical simulation

    Science.gov (United States)

    Lindsey, W. C.; Kantak, A. V.; Chie, C. M.; Booth, R. W. D.

    1979-01-01

    A solar power satellite transmission system which incorporates automatic beam forming, steering, and phase control is discussed. The phase control concept centers around the notation of an active retrodirective phased array as a means of pointing the beam to the appropriate spot on Earth. The transmitting antenna (spacetenna) directs the high power beam so that it focuses on the ground-based receiving antenna (rectenna). A combination of analysis and computerized simulation was conducted to determine the far field performance of the reference distribution system, and the beam forming and microwave power generating systems.

  2. Superfluid phase transition in two-dimensional excitonic systems

    Energy Technology Data Exchange (ETDEWEB)

    Apinyan, V.; Kopeć, T.K., E-mail: kopec@int.pan.wroc.pl

    2014-03-01

    We study the superfluid phase transition in the two-dimensional (2D) excitonic system. Employing the extended Falicov–Kimball model (EFKM) and considering the local quantum correlations in the system composed of conduction band electrons and valence band holes we demonstrate the existence of the excitonic insulator (EI) state in the system. We show that at very low temperatures, the particle phase stiffness in the pure-2D excitonic system, governed by the non-local cross correlations, is responsible for the vortex–antivortex binding phase-field state, known as the Berezinskii–Kosterlitz–Thouless (BKT) superfluid state. We demonstrate that the existence of excitonic insulator phase is a necessary prerequisite, leading to quasi-long-range order in the 2D excitonic system.

  3. Single-to-three phase induction motor sensorless drive system

    Directory of Open Access Journals (Sweden)

    Z.M.S. El-Barbary

    2012-06-01

    Full Text Available This paper presented a single to three-phase induction motor drive system to provide variable output voltage and frequency. The proposed drive system employs only six IGBT switches, which form the front-end rectifier and the output inverter for the one step conversion from single-phase supply to output three-phase supply. The front-end rectifier permits bidirectional power flow and provides excellent regulation against fluctuations in source voltage. Moreover, it incorporates active input current shaping feature. The control strategy of the proposed drive system of three-phase induction motor is based on speed sensorless vector control technique. A low cost of motor drive and much more advantages can be achieved using the proposed drive system. Simulation and experimental results are carried out to analysis and explore the characteristics of the proposed drive system.

  4. Technology verification phase. Dynamic isotope power system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Halsey, D.G.

    1982-03-10

    The Phase I requirements of the Kilowatt Isotope Power System (KIPS) program were to make a detailed Flight System Conceptual Design (FSCD) for an isotope fueled organic Rankine cycle power system and to build and test a Ground Demonstration System (GDS) which simulated as closely as possible the operational characteristics of the FSCD. The activities and results of Phase II, the Technology Verification Phase, of the program are reported. The objectives of this phase were to increase system efficiency to 18.1% by component development, to demonstrate system reliability by a 5000 h endurance test and to update the flight system design. During Phase II, system performance was improved from 15.1% to 16.6%, an endurance test of 2000 h was performed while the flight design analysis was limited to a study of the General Purpose Heat Source, a study of the regenerator manufacturing technique and analysis of the hardness of the system to a laser threat. It was concluded from these tests that the GDS is basically prototypic of a flight design; all components necessary for satisfactory operation were demonstrated successfully at the system level; over 11,000 total h of operation without any component failure attested to the inherent reliability of this type of system; and some further development is required, specifically in the area of performance. (LCL)

  5. Phase Relationship in Phenol-Insulin Crystal Growth System

    Institute of Scientific and Technical Information of China (English)

    梁栋材; 宋浪舟; 万柱礼; 常文瑞

    1994-01-01

    Based on the crystal growth system of rhombohedral 2Zn-insulin,the phase transition ofinsulin crystals has been investigated with the phenol concentration as an independent component.The dia-gram of the phase relationship in this crystal growth system was established,and two points of phase transi-tion were found.The transition point Ⅰ indicates the phase transition between rhombohedral 2Zn-insulin crys-tal and rhombohedral 4Zn-insulin crystal,and these two phases coexist within a narrow region of phenol con-centration (0.028%-0.029% (g/ml)).Point Ⅱ at 0.76%-0.77% (g/ml) of phenol concentration showsthe phase transition between rhombohcdral crystal and monoclinic crystals,and a new phase of monocliniccrystal (B-form monoclinic insulin crystal) has been observed.This paper reports the diagram of phase rela-tionship obtained from our experiments,and analyses and discusses the dependence of phase transition of in-sulin crystals on phenol concentration in crystal growth system.

  6. Traffic management system: Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-30

    This report, conducted by Louis Berger International, Inc., was funded by the US Trade and Development Agency. This report identifies the primary and secondary air traffic networks inside and outside Buenos Aires Metropolitan Area where particular safety and traffic problems exist. The Consortium Louis Berger International, Inc.-IBI Group-UBATEC provides recommendations divided into two groups: one based on engineering aspects for each identified deficiency in the selected routes; and a second group that is based on the results of the evaluation of needs. This is Volume 3, Phase 2 Final Report, and it consists of the following: (1) Introduction; (2) Existing Conditions and Deficiencies; (3) Recommendations; and (4) Appendix: Definition of the Primary Network of the Metropolitan Area.

  7. Phase stability in nanoscale material systems: extension from bulk phase diagrams.

    Science.gov (United States)

    Bajaj, Saurabh; Haverty, Michael G; Arróyave, Raymundo; Goddard, William A; Shankar, Sadasivan

    2015-06-07

    Phase diagrams of multi-component systems are critical for the development and engineering of material alloys for all technological applications. At nano dimensions, surfaces (and interfaces) play a significant role in changing equilibrium thermodynamics and phase stability. In this work, it is shown that these surfaces at small dimensions affect the relative equilibrium thermodynamics of the different phases. The CALPHAD approach for material surfaces (also termed "nano-CALPHAD") is employed to investigate these changes in three binary systems by calculating their phase diagrams at nano dimensions and comparing them with their bulk counterparts. The surface energy contribution, which is the dominant factor in causing these changes, is evaluated using the spherical particle approximation. It is first validated with the Au-Si system for which experimental data on phase stability of spherical nano-sized particles is available, and then extended to calculate phase diagrams of similarly sized particles of Ge-Si and Al-Cu. Additionally, the surface energies of the associated compounds are calculated using DFT, and integrated into the thermodynamic model of the respective binary systems. In this work we found changes in miscibilities, reaction compositions of about 5 at%, and solubility temperatures ranging from 100-200 K for particles of sizes 5 nm, indicating the importance of phase equilibrium analysis at nano dimensions.

  8. General Motors Phase II Catalyst System

    Energy Technology Data Exchange (ETDEWEB)

    Canale, R.P.; Winegarden, S.R.; Carlson, C.R.; Miles, D.L.

    1978-01-01

    Three-way catalysts provide a means of catalytically achieving lower NOx emission levels while maintaining good control of HC and CO emissions. However, very accurate control of air-fuel ratio is necessary. The precise air-fuel ratio control required is accomplished by employing a closed loop fuel metering system in conjunction with an exhaust gas sensor and an electronic control unit. To gain production experience with this type of system, General Motors is introducing it on two 1978 engine families sold in California. One is a 2.5 liter L-4 engine and the other is a 3.8 liter V-6 engine. Closed loop controlled carburetors are used on both systems. The components used on both systems are described and emission and fuel economy results are reviewed.

  9. Flexible manufacturing system (FMS): The investigative phase

    Energy Technology Data Exchange (ETDEWEB)

    Setter, D.L.

    1992-02-01

    An investigation has been conducted into the feasibility of using flexible manufacturing system (FMS) technology to machine and inspect a family of stainless steel and aluminum parts for electrical components. The investigation was conducted by a user-oriented team of KCD personnel with the help of an outside consultant. The investigation showed that FMS was appropriate and justifiable for the KCD application. A project was initiated to purchase and implement an FMS system. 1 ref.

  10. Design of Training Systems Phase I Summary Report.

    Science.gov (United States)

    Lindahl, William H.; And Others

    A summary is provided of the status of Phase I of the three-stage project, "Design of Training Systems" (DOTS). The purpose of the overall project is described as being to introduce the technologies of education, psychology, management and operations research into the management of Navy training. Phase I of the effort is designed to…

  11. A regressed phase analysis for coupled joint systems.

    Science.gov (United States)

    Wininger, Michael

    2011-01-01

    This study aims to address shortcomings of the relative phase analysis, a widely used method for assessment of coupling among joints of the lower limb. Goniometric data from 15 individuals with spastic diplegic cerebral palsy were recorded from the hip and knee joints during ambulation on a flat surface, and from a single healthy individual with no known motor impairment, over at least 10 gait cycles. The minimum relative phase (MRP) revealed substantial disparity in the timing and severity of the instance of maximum coupling, depending on which reference frame was selected: MRP(knee-hip) differed from MRP(hip-knee) by 16.1±14% of gait cycle and 50.6±77% difference in scale. Additionally, several relative phase portraits contained discontinuities which may contribute to error in phase feature extraction. These vagaries can be attributed to the predication of relative phase analysis on a transformation into the velocity-position phase plane, and the extraction of phase angle by the discontinuous arc-tangent operator. Here, an alternative phase analysis is proposed, wherein kinematic data is transformed into a profile of joint coupling across the entire gait cycle. By comparing joint velocities directly via a standard linear regression in the velocity-velocity phase plane, this regressed phase analysis provides several key advantages over relative phase analysis including continuity, commutativity between reference frames, and generalizability to many-joint systems.

  12. Road Transportable Analytical Laboratory system. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Finger, S.M.; Keith, V.F.; Spertzel, R.O.; De Avila, J.C.; O`Donnell, M.; Vann, R.L.

    1993-09-01

    This developmental effort clearly shows that a Road Transportable Analytical Laboratory System is a worthwhile and achievable goal. The RTAL is designed to fully analyze (radioanalytes, and organic and inorganic chemical analytes) 20 samples per day at the highest levels of quality assurance and quality control. It dramatically reduces the turnaround time for environmental sample analysis from 45 days (at a central commercial laboratory) to 1 day. At the same time each RTAL system will save the DOE over $12 million per year in sample analysis costs compared to the costs at a central commercial laboratory. If RTAL systems were used at the eight largest DOE facilities (at Hanford, Savannah River, Fernald, Oak Ridge, Idaho, Rocky Flats, Los Alamos, and the Nevada Test Site), the annual savings would be $96,589,000. The DOE`s internal study of sample analysis needs projects 130,000 environmental samples requiring analysis in FY 1994, clearly supporting the need for the RTAL system. The cost and time savings achievable with the RTAL system will accelerate and improve the efficiency of cleanup and remediation operations throughout the DOE complex.

  13. WDM Phase-Modulated Millimeter-Wave Fiber Systems

    DEFF Research Database (Denmark)

    Yu, Xianbin; Prince, Kamau; Gibbon, Timothy Braidwood

    2012-01-01

    This chapter presents a computer simulation case study of two typical WDM phase-modulated millimeter-wave systems. The phase-modulated 60 GHz fiber multi-channel transmission systems employ single sideband (SSB) and double sideband subcarrier modulation (DSB-SC) schemes and present one of the lat......This chapter presents a computer simulation case study of two typical WDM phase-modulated millimeter-wave systems. The phase-modulated 60 GHz fiber multi-channel transmission systems employ single sideband (SSB) and double sideband subcarrier modulation (DSB-SC) schemes and present one...... of the latest research efforts in the rapidly emerging Radio-over-Fiber (RoF) application space for in-house access networks....

  14. Phase Space Structures of k-threshold Sequential Dynamical Systems

    CERN Document Server

    Rani, Raffaele

    2011-01-01

    Sequential dynamical systems (SDS) are used to model a wide range of processes occurring on graphs or networks. The dynamics of such discrete dynamical systems is completely encoded by their phase space, a directed graph whose vertices and edges represent all possible system configurations and transitions between configurations respectively. Direct calculation of the phase space is in most cases a computationally demanding task. However, for some classes of SDS one can extract information on the connected component structure of phase space from the constituent elements of the SDS, such as its base graph and vertex functions. We present a number of novel results about the connected component structure of the phase space for k-threshold dynamical system with binary state spaces. We establish relations between the structure of the components, the threshold value, and the update sequence. Also fixed-point reachability from garden of eden configurations is investigated and upper bounds for the length of paths in t...

  15. Berry phase in a generalized nonlinear two-level system

    Institute of Scientific and Technical Information of China (English)

    Liu Ji-Bing; Li Jia-Hua; Song Pei-Jun; Li Wei-Bin

    2008-01-01

    In this paper,we investigate the behaviour of the geometric phase of a more generalized nonlinear system composed of an effective two-level system interacting with a single-mode quantized cavity field.Both the field nonlinearity and the atom-field coupling nonlinearity are considered.We find that the geometric phase depends on whether the index k is an odd number or an even number in the resonant case.In addition,we also find that the geometric phase may be easily observed when the field nonlinearity is not considered.The fractional statistical phenomenon appears in this system if the strong nonlinear atom-field coupling is considered.We have also investigated the geometric phase of an effective two-level system interacting with a two-mode quantized cavity field.

  16. Scaling of Two-Phase Systems Across Gravity Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a defined need for long term earth based testing for the development and deployment of two-phase flow systems in reduced-gravity, including lunar gravity,...

  17. Space law information system design, phase 2

    Science.gov (United States)

    Morenoff, J.; Roth, D. L.; Singleton, J. W.

    1973-01-01

    Design alternatives were defined for the implementation of a Space Law Information System for the Office of the General Counsel, NASA. A thesaurus of space law terms was developed and a selected document sample indexed on the basis of that thesaurus. Abstracts were also prepared for the sample document set.

  18. Phase structure rewrite systems in information retrieval

    Science.gov (United States)

    Klingbiel, P. H.

    1985-01-01

    Operational level automatic indexing requires an efficient means of normalizing natural language phrases. Subject switching requires an efficient means of translating one set of authorized terms to another. A phrase structure rewrite system called a Lexical Dictionary is explained that performs these functions. Background, operational use, other applications and ongoing research are explained.

  19. Crusader Automated Docking System Phase 3 report

    Energy Technology Data Exchange (ETDEWEB)

    Jatko, W.B.; Goddard, J.S.; Ferrell, R.K.; Gleason, S.S.; Hicks, J.S.; Varma, V.K.

    1996-03-01

    The US Army is developing the next generation of battlefield artillery vehicles, including an advanced, self-propelled howitzer and a companion resupply vehicle. The resupply vehicle is intended to rendezvous with the howitzer near the battlefront and to upload ammunition to the howitzer. The Army has recommended that the vehicles incorporate robotics to increase safety, by allowing the crew to remain inside their vehicles during resupply operations. Oak Ridge National Laboratory has developed an autonomous docking system for a 6-D.F. robotic, ammunition transfer arm. The docking system augments the operator`s abilities by determining the position and orientation (pose) of a docking port. The pose is the location of the x, y, and z reference axes in 3-D space; and the orientation is the rotations--roll, pitch, and yaw--about those axes. Bye precisely determining the pose of the docking port, the robot can be instructed to move to the docking position without operator intervention. The system uses a video camera and frame grabber to digitize images of the special docking port. Custom algorithms were developed to recognize the port in the camera image, to determine the pose from its image features, and to distribute the results to the robot control computer. The system is loosely coupled to the robot and can be easily adapted to different mechanical configurations. The system has successfully demonstrated autonomous docking on a 24-in. tabletop robot and a 12-ft ammunition resupply robot. The update rate, measurement accuracy, continuous operation, and accuracy with obstructed view have been determined experimentally.

  20. Integrated thermal treatment system study -- Phase 2 results. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Quapp, W.J.

    1996-02-01

    This report presents the second phase of a study on thermal treatment technologies. The study consists of a systematic assessment of nineteen thermal treatment alternatives for the contact-handled mixed low-level waste (MLLW) currently stored in the US Department of Energy complex. The treatment alternatives consist of widely varying technologies for safely destroying the hazardous organic components, reducing the volume, and preparing for final disposal of the MLLW. The alternatives considered in Phase 2 were innovative thermal treatments with nine types of primary processing units. Other variations in the study examined the effect of combustion gas, air pollution control system design, and stabilization technology for the treatment residues. The Phase 1 study examined ten initial thermal treatment alternatives. The Phase 2 systems were evaluated in essentially the same manner as the Phase 1 systems. The alternatives evaluated were: rotary kiln, slagging kiln, plasma furnace, plasma gasification, molten salt oxidation, molten metal waste destruction, steam gasification, Joule-heated vitrification, thermal desorption and mediated electrochemical oxidation, and thermal desorption and supercritical water oxidation. The quantities, and physical and chemical compositions, of the input waste used in the Phase 2 systems differ from those in the Phase 1 systems, which were based on a preliminary waste input database developed at the onset of the Integrated Thermal Treatment System study. The inventory database used in the Phase 2 study incorporates the latest US Department of Energy information. All systems, both primary treatment systems and subsystem inputs, have now been evaluated using the same waste input (2,927 lb/hr). 28 refs., 88 figs., 41 tabs.

  1. Decryption of a random-phase multiplexing recording system

    Science.gov (United States)

    Chang, Chi-Ching; Liu, Jung-Ping; Lee, Hsiao-Yi; Lin, Ching-Yang; Chang, Tsung-Chien; Yau, Hon-Fai

    2006-03-01

    In practice, decrypting a random-phase encrypted volume holographic data storage system is impossible unless the original random-phase plate for the encryption is available. However, this study demonstrates that under certain conditions, ways are available that can decrypt an encrypted photorefractive LiNbO3 crystal holographic storage system. In addition to presenting experimental results that show the efficacy of this decryption approach, problems and difficulties in the experiments are discussed.

  2. Multi-Phase Galaxy Formation and Quasar Absorption Systems

    OpenAIRE

    Maller, Ariyeh H.

    2005-01-01

    The central problem of galaxy formation is understanding the cooling and condensation of gas in dark matter halos. It is now clear that to match observations this requires further physics than the simple assumptions of single phase gas cooling. A model of multi-phase cooling (Maller & Bullock 2004) can successfully account for the upper cutoff in the masses of galaxies and provides a natural explanation of many types of absorption systems (Mo & Miralda-Escude 1996). Absorption systems are our...

  3. Observability of Airborne Passive Location System with Phase Difference Measurements

    Institute of Scientific and Technical Information of China (English)

    Deng Xinpu; Wang Qiang; Zhong Danxing

    2008-01-01

    With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision.

  4. Phase diagram studies on the Na-Mo-O system

    Science.gov (United States)

    Gnanasekaran, T.; Mahendran, K. H.; Kutty, K. V. G.; Mathews, C. K.

    1989-06-01

    The phase diagram of the Na-Mo-O ternary system is of interest in interpreting the behaviour of structural materials in the sodium circuits of fast breeder reactors and sodium-filled heat pipes. Experiments involving heating of sodium oxide with molybdenum metal under vacuum, selective removal of oxygen from polymolybdates by reducing them under hydrogen and confirmation of the coexistence of various phase mixtures were conducted in the temperature range of 673 to 923 K. Phase fields involving molybdenum metal, dioxide of molybdenum and ternary compounds were derived from these results. The ternary phase diagram of the Na-Mo-O system was constructed and isothermal cross sections of the phase diagram are presented.

  5. Random shortcuts induce phase synchronization in complex Chua systems

    Institute of Scientific and Technical Information of China (English)

    Wei Du-Qu; Luo Xiao-Shu; Qin Ying-Hua

    2009-01-01

    This paper studies how phase synchronization in complex networks depends on random shortcuts, using the piecewise-continuous chaotic Chua system as the nodes of the networks. It is found that for a given coupling strength,when the number of random shortcuts is greater than a threshold the phase synchronization is induced. Phase synchronization becomes evident and reaches its maximum as the number of random shortcuts is further increased. These phenomena imply that random shortcuts can induce and enhance the phase synchronization in complex Chua systems.Furthermore, the paper also investigates the effects of the coupling strength and it is found that stronger coupling makes it easier to obtain the complete phase synchronization.

  6. VARIANCE OF NONLINEAR PHASE NOISE IN FIBER-OPTIC SYSTEM

    Directory of Open Access Journals (Sweden)

    RANJU KANWAR

    2013-04-01

    Full Text Available In communication system, the noise process must be known, in order to compute the system performance. The nonlinear effects act as strong perturbation in long- haul system. This perturbation effects the signal, when interact with amplitude noise, and results in random motion of the phase of the signal. Based on the perturbation theory, the variance of nonlinear phase noise contaminated by both self- and cross-phase modulation, is derived analytically for phase-shift- keying system. Through this work, it is investigated that for longer transmission distance, 40-Gb/s systems are more sensitive to nonlinear phase noise as compared to 50-Gb/s systems. Also, when transmitting the data through the fiber optic link, bit errors are produced due to various effects such as noise from optical amplifiers and nonlinearity occurring in fiber. On the basis of the simulation results , we have compared the bit error rate based on 8-PSK with theoretical results, and result shows that in real time approach, the bit error rate is high for the same signal to noise ratio. MATLAB software is used to validate the analytical expressions for the variance of nonlinear phase noise.

  7. Intelligent Robotic Systems Study (IRSS), phase 2

    Science.gov (United States)

    1990-01-01

    Under the Intelligent Robotics System Study (IRSS) contract, a generalized robotic control architecture was developed for use with the ProtoFlight Manipulator Arm (PFMA). The controller built for the PFMA provides localized position based force control, teleoperation and advanced path recording and playback capabilities. Various hand controllers can be used with the system in conjunction with a synthetic time delay capability to provide a realistic test bed for typical satellite servicing tasks. The configuration of the IRSS system is illustrated and discussed. The PFMA has six computer controllable degrees of freedom (DOF) plus a seventh manually indexable DOF, making the manipulator a pseudo 7 DOF mechanism. Because the PFMA was not developed to operate in a gravity field, but rather in space, it is counter balanced at the shoulder, elbow and wrist and a spring counterbalance has been added near the wrist to provide additional support. Built with long slender intra-joint linkages, the PFMA has a workspace nearly 2 meters deep and possesses sufficient dexterity to perform numerous satellite servicing tasks. The manipulator is arranged in a shoulder-yaw, pitch, elbow-pitch, and wrist-pitch, yaw, roll configuration, with an indexable shoulder roll joint. Digital control of the PFMA is implemented using a variety of single board computers developed by Heurikon Corporation and other manufacturers. The IRSS controller is designed to be a multi-rate, multi-tasking system. Independent joint servos run at a 134 Hz rate and position based impedance control functions at 67 Hz. Autonomous path generation and hand controller inputs are processed at a 33 Hz.

  8. The Phase 2 Upgrade of the LHCb Muon System

    CERN Document Server

    Bencivenni, Giovanni; Cardini, Alessandro; Maev, Oleg; Passaleva, Giovanni; Pinci, Davide

    2013-01-01

    To deal with upgrade luminosities, the muon group is currently planning a muon system upgrade in two phases. In the first phase the muon system will be modified by replacing the off-detector electronics with new electronics compliant with the 40 MHz readout rate through TELL40. Then, in a second phase, higher readout granularity detectors will be installed in the central regions of the first muon stations, to overcome the efficiency losses due to the increase of detector dead-time caused by the higher luminosities and to use detector technologies that can operate reliably in these highly irradiated regions, where detectors' aging will become an issue.

  9. Superradiant phase transitions with three-level systems

    Science.gov (United States)

    Baksic, Alexandre; Nataf, Pierre; Ciuti, Cristiano

    2013-02-01

    We determine the phase diagram of N identical three-level systems interacting with a single photonic mode in the thermodynamical limit (N→∞) by accounting for the so-called diamagnetic term and the inequalities imposed by the Thomas-Reich-Kuhn (TRK) oscillator strength sum rule. The key role of transitions between excited levels and the occurrence of first-order phase transitions is discussed. We show that, in contrast to two-level systems, in the three-level case the TRK inequalities do not always prevent a superradiant phase transition in the presence of a diamagnetic term.

  10. Superradiant phase transitions with three-level systems

    CERN Document Server

    Baksic, Alexandre; Ciuti, Cristiano

    2013-01-01

    We determine the phase diagram of $N$ identical three-level systems interacting with a single photonic mode in the thermodynamical limit ($N \\to \\infty$) by accounting for the so-called diamagnetic term and the inequalities imposed by the Thomas-Reich-Kuhn (TRK) oscillator strength sum rule. The key role of transitions between excited levels and the occurrence of first-order phase transitions is discussed. We show that, in contrast to two-level systems, in the three-level case the TRK inequalities do not always prevent a superradiant phase transition in presence of a diamagnetic term.

  11. Effect of phase noise in an OFDM/OQAM system

    Institute of Scientific and Technical Information of China (English)

    ChenQifan; WuBingyang; ChengShixin

    2003-01-01

    The performance of an OFDM/OQAM system under phase noise is analyzed. The analysis helps to direct the design of low cost tuners through specifying the required phase noise characteristics. Discrete time formulation of OFDM/OQAM is first derived with the square root raised cosine (SRRC) filter as the pulse-shaping filter. Then the effect of multiplicative phase noise is equivalently represented as additive white Gaussian noise (AWGN), the variance of which is given analytically. We can observe that the same result as OFDM/QAM system is derived. Lastly, all the analytical results are verified by the bit error rate (BER) degradation through Monte Carlo simulation.

  12. Phase Noise Monitor and Reduction by Parametric Saturation Approach in Phase Modulation Systems

    Institute of Scientific and Technical Information of China (English)

    XU Ming; ZHOU Zhen; PU Xiao; JI Jian-Hua; YANG Shu-Wen

    2011-01-01

    Nonlinear phase noise (NLPN) is investigated theoretically and numerically to be mitigated by parametric saturation approach in DPSK systems.The nonlinear propagation equation that incorporates the phase of linear and nonlinear is analyzed with parametric saturation processing (PSP).The NLPN is picked and monitored with the power change factors in the DPSK system.This process can be realized by an optical PSP limiter and a novel apparatus with feedback MZI.The monitor range of phase noise is 0°-90°, which may be reduced to 0°-45°if the monitor factor is about the Stockes wave but not an anti-Stockes wave.It is shown that DPSK signal performance can be improved based on the parametric saturation approach.%@@ Nonlinear phase noise (NLPN) is investigated theoretically and numerically to be mitigated by parametric saturation approach in DPSK systems.The nonlinear propagation equation that incorporates the phase of linear and nonlinear is analyzed with parametric saturation processing (PSP).The NLPN is picked and monitored with the power change factors in the DPSK system.This process can be realized by an optical PSP limiter and a novel apparatus with feedback MZI.The monitor range of phase noise is 0°-90°, which may be reduced to 0°-45° if the monitor factor is about the Stockes wave but not an anti-Stockes wave.It is shown that DPSK signal performance can be improved based on the parametric saturation approach.

  13. Nonlinear phase noise mitigation in phase-sensitive amplified transmission systems.

    Science.gov (United States)

    Olsson, Samuel L I; Karlsson, Magnus; Andrekson, Peter A

    2015-05-04

    We investigate the impact of in-line amplifier noise in transmission systems amplified by two-mode phase-sensitive amplifiers (PSAs) and present the first experimental demonstration of nonlinear phase noise (NLPN) mitigation in a modulation format independent PSA-amplified transmission system. The NLPN mitigation capability is attributed to the correlated noise on the signal and idler waves at the input of the transmission span. We study a single-span system with noise loading in the transmitter but the results are expected to be applicable also in multi-span systems. The experimental investigation is supported by numerical simulations showing excellent agreement with the experiments. In addition to demonstrating NLPN mitigation we also present a record high sensitivity receiver, enabled by low-noise PSA-amplification, requiring only 4.1 photons per bit to obtain a bit error ratio (BER) of 1 × 10(-3) with 10 GBd quadrature phase-shift keying (QPSK) data.

  14. Topological phases in condensed matter systems: A study of symmetries, quasiparticles and phase transitions

    NARCIS (Netherlands)

    Haaker, S.M.

    2014-01-01

    The research described in this thesis focuses on topological phases in condensed matter systems. It can be roughly divided into two parts. In the first part noninteracting systems are studied. The symmetry algebra of a charged spin-1/2 particle coupled to a non-Abelian magnetic field is determined,

  15. Study on low-phase-noise optoelectronic oscillator and high-sensitivity phase noise measurement system.

    Science.gov (United States)

    Hong, Jun; Liu, An-min; Guo, Jian

    2013-08-01

    An analytic model for an injection-locked dual-loop optoelectronic oscillator (OEO) is proposed and verified by experiments in this paper. Based on this theoretical model, the effect of injection power on the single-sideband phase noise of the OEO is analyzed, and results suggest that moderate injection is one key factor for a balance between phase noise and spur for OEO. In order to measure superlow phase noise of OEOs, a cross-correlation measurement system based on the fiber delay line is built, in which high linear photodetector and low-phase-noise amplifier are used to improve systematic sensitivity. The cross-correlation measurement system is validated by experiments, and its noise floor for the X band is about -130 dBc/Hz at 1 kHz and -168 dBc/Hz at 10 kHz after a cross correlation of 200 times.

  16. Design of Phase Feed Forward System in CTF3 and Performance of Fast Beam Phase Monitors

    CERN Document Server

    Skowronski, P K; Ghigo, A; Marcellini, F; Burrows, PN; Christian, GB; Perry, C; Gerbershagen, A; Roberts, J; Ikarios, E

    2013-01-01

    The CLIC two beam acceleration technology requires a drive beam phase stability better than 0.3 deg rms at 12 GHz, corresponding to a timing stability below 50 fs rms. For this reason the CLIC design includes a phase stabilization feed-forward system. It relies on precise beam phase measurements and their subsequent correction in a chicane with the help of fast kickers. A prototype of such a system is being installed in the CLIC Test Facility CTF3. In this paper its design and implementation is described in detail. Additionally, the performance of the precision phase monitor prototypes installed at the end of the CTF3 linac, as measured with the drive beam, is presented.

  17. A TWO-PHASE APPROACH TO FUZZY SYSTEM IDENTIFICATION

    Institute of Scientific and Technical Information of China (English)

    Ta-Wei HUNG; Shu-Cherng FANG; Henry L.W.NUTTLE

    2003-01-01

    A two-phase approach to fuzzy system identification is proposed. The first phase produces a baseline design to identify a prototype fuzzy system for a target system from a coIlection of input-output data pairs. It uses two easily implemented clustering techniques: the subtractive clustering method and the fuzzy c-means (FCM) clustering algorithm. The second phase (fine tuning)is executed to adjust the parameters identified in the baseline design. This phase uses the steepest descent and recursive least-squares estimation methods. The proposed approach is validated by applying it to both a function approximation type of problem and a classification type of problem. An analysis of the learning behavior of the proposed approach for the two test problems is conducted for further confirmation.

  18. PHASE EQUILIBRIA INVESTIGATION OF BINARY, TERNARY, AND HIGHER ORDER SYSTEMS. PART 9. CALCULATION OF THERMODYNAMIC QUANTITIES FROM PHASE DIAGRAMS

    Science.gov (United States)

    The thermodynamic fundamentals relating phase equilibria in binary and ternary systems to the thermodynamic properties of the phases are reviewed and...system demonstrate the application of the equations for extracting thermodynamic data from phase diagrams and also for the prediction of phase equilibria .

  19. Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System

    Directory of Open Access Journals (Sweden)

    Tian Wang

    2016-12-01

    Full Text Available Ce-Fe-Co-B is a promising system for permanent magnets. A high-throughput screening method combining diffusion couples, key alloys, Scanning Electron Microscope/Wavelength Dispersive X-ray Spectroscope (SEM/WDS, and Magnetic Force Microscope (MFM is used in this research to understand the phase equilibria and to explore promising magnetic phases in this system. Three magnetic phases were detected and their homogeneity ranges were determined at 900 °C, which were presented by the formulae: Ce2Fe14−xCoxB (0 ≤ x ≤ 4.76, CeCo4−xFexB (0 ≤ x ≤ 3.18, and Ce3Co11−x FexB4 (0 ≤ x ≤ 6.66. The phase relations among the magnetic phases in this system have been studied. Ce2(Fe, Co14B appears to have stronger magnetization than Ce(Co, Fe4B and Ce3(Co, Fe11B4 from MFM analysis when comparing the magnetic interactions of selected key alloys. Also, a non-magnetic CeCo12−xFexB6 (0 ≤ x ≤ 8.74 phase was detected in this system. A boron-rich solid solution with Ce13FexCoyB45 (32 ≤ x ≤ 39, 3 ≤ y ≤ 10 chemical composition was also observed. However, the crystal structure of this phase could not be found in the literature. Moreover, ternary solid solutions ε1 (Ce2Fe17−xCox (0 ≤ x ≤ 12.35 and ε2 (Ce2Co17−xFex (0 ≤ x ≤ 3.57 were found to form between Ce2Fe17 and Ce2Co17 in the Ce-Fe-Co ternary system at 900 °C.

  20. Phase Equilibria and Magnetic Phases in the Ce-Fe-Co-B System.

    Science.gov (United States)

    Wang, Tian; Kevorkov, Dmytro; Medraj, Mamoun

    2016-12-28

    Ce-Fe-Co-B is a promising system for permanent magnets. A high-throughput screening method combining diffusion couples, key alloys, Scanning Electron Microscope/Wavelength Dispersive X-ray Spectroscope (SEM/WDS), and Magnetic Force Microscope (MFM) is used in this research to understand the phase equilibria and to explore promising magnetic phases in this system. Three magnetic phases were detected and their homogeneity ranges were determined at 900 °C, which were presented by the formulae: Ce₂Fe14-xCoxB (0 ≤ x ≤ 4.76), CeCo4-xFexB (0 ≤ x ≤ 3.18), and Ce₃Co11-x FexB₄ (0 ≤ x ≤ 6.66). The phase relations among the magnetic phases in this system have been studied. Ce₂(Fe, Co)14B appears to have stronger magnetization than Ce(Co, Fe)₄B and Ce₃(Co, Fe)11B₄ from MFM analysis when comparing the magnetic interactions of selected key alloys. Also, a non-magnetic CeCo12-xFexB₆ (0 ≤ x ≤ 8.74) phase was detected in this system. A boron-rich solid solution with Ce13FexCoyB45 (32 ≤ x ≤ 39, 3 ≤ y ≤ 10) chemical composition was also observed. However, the crystal structure of this phase could not be found in the literature. Moreover, ternary solid solutions ε₁ (Ce₂Fe17-xCox (0 ≤ x ≤ 12.35)) and ε₂ (Ce₂Co17-xFex (0 ≤ x ≤ 3.57)) were found to form between Ce₂Fe17 and Ce₂Co17 in the Ce-Fe-Co ternary system at 900 °C.

  1. On Blind MIMO System Identification Based on Second-Order Cyclic Statistics

    Directory of Open Access Journals (Sweden)

    K. Sabri

    2008-01-01

    Full Text Available This letter introduces a new frequency domain approach for either MIMO System Identification or Source Separation of convolutive mixtures in cyclostationary context. We apply the joint diagonalization algorithm to a set of cyclic spectral density matrices of the measurements to identify the mixing system at each frequency up to permutation and phase ambiguity matrices. An efficient algorithm to overcome the frequency dependent permutations and to recover the phase, even for non-minimum-phase channels, based on cyclostationarity is also presented. The new approach exploits the fact that each input has a different and specific cyclic frequency. A comparison with an existing MIMO method is proposed.

  2. Characterization of phases in the Fe-Nb system

    Science.gov (United States)

    Raposo, M. T.; Ardisson, J. D.; Persiano, A. I. C.; Mansur, R. A.

    1994-12-01

    The Fe-Nb system was investigated by means of X-ray diffraction and Mössbauer spectroscopy (at 300 and 77 K), in the range from 1 to 66.7 at%. We have found that the limit of solubility of Fe in Nb at 1100°C is between 3 and 4 at% Fe, and observed the coexistence of the Nb solid solution (Nbss) phase and Fe21Nb19 in the range from 4 to 40 at% Fe. The Mössbauer parameters of all the single phases are reported. The lattice parameters of Nbss phase present no significant variation with the Nb content. The X-ray pattern for the Fe21Nb19 phase could not be solved. The Laves phase Fe2Nb presents Mössbauer and X-ray parameters that agree with the literature.

  3. Implementation of concurrent engineering to Phase B space system design

    Science.gov (United States)

    Findlay, R.; Braukhane, A.; Schubert, D.; Pedersen, J. F.; Müller, H.; Essmann, O.

    2011-12-01

    Concurrent engineering (CE) has been in use within the space industry since the mid-1990s for the development of robust, effective design solutions within a reduced period of time; to date, however, such applications have focussed on Phase 0/A feasibility studies, with the potential for application in later phases not yet demonstrated. Applications at the DLR Institute of Space Systems have addressed this gap with practical attempts made on three satellite projects. The use of Phase 0/A CE techniques, such as dedicated CE sessions, online trade-offs, and design iterations and consolidation, was taken and augmented with more novel practices such as online requirements engineering. Underlying these practices was a suite of tools coming from both external and internal sources. While it is noted that the traditional time and cost benefits expected from Phase 0/A use are less likely to be achieved for Phase B applications, the resulting solutions demonstrated an increased robustness and performance.

  4. Design of IR EDM System with a DSP Phase Detector①

    Institute of Scientific and Technical Information of China (English)

    LIUJianguo; WEIQingnong

    1997-01-01

    The design and realization of a new generation of infra-red electronic distance measurement(IR EDM)system are presented.A DSP(Digital Signal Process)phase detector based on high speed analog-to-digital converter and DSP technique has been designed,in order to improve the precision and reliability of IR EDM system.As a result,the EDM system developed with a DSP phase detector has a precision of 3mm in the measuring range of 2 km.

  5. Performance of the beam phase measurement system for LEDA

    Science.gov (United States)

    Power, J. F.; Barr, D.; Gilpatrick, J. D.; Kasemir, K.; Shurter, R. B.; Stettler, M.

    2000-11-01

    The Low Energy Demonstration Accelerator (LEDA) facility diagnostics include beam phase measurements [1]. Beam signals at 350 MHz from capacitive probes are down-converted to 2 MHz for processing. The phase measurement process includes amplitude leveling, digital sampling of the I and Q vectors, DSP filtering and calibration, and serving of the data to the network. All hardware is fielded in the VXI format and controlled with a PC. Running under Windows NT, a LabVIEW® program controls the operation of the system and serves the data, via channel access, to the EPICS control system. The design and operational performance to date of the system is described.

  6. Energy-dissipation-model for metallurgical multi-phase-systems

    Energy Technology Data Exchange (ETDEWEB)

    Mavrommatis, K.T. [Rheinisch-Westfaelische Technische Hochschule Aachen, Aachen (Germany)

    1996-12-31

    Entropy production in real processes is directly associated with the dissipation of energy. Both are potential measures for the proceed of irreversible processes taking place in metallurgical systems. Many of these processes in multi-phase-systems could then be modelled on the basis of the energy-dissipation associated with. As this entity can often be estimated using very simple assumptions from first principles, the evolution of an overall measure of systems behaviour can be studied constructing an energy-dissipation -based model of the system. In this work a formulation of this concept, the Energy-Dissipation-Model (EDM), for metallurgical multi-phase-systems is given. Special examples are studied to illustrate the concept, and benefits as well as the range of validity are shown. This concept might be understood as complement to usual CFD-modelling of complex systems on a more abstract level but reproducing essential attributes of complex metallurgical systems. (author)

  7. Interfacial properties and phase behaviour of an ionic microemulsion system

    NARCIS (Netherlands)

    Kegel, W.K.

    1993-01-01

    This thesis reports a study of a microemulsion model system composed of the ionic surfactant SDS (Sodium Dodecyl Sulfate), the cosurfactant pentanol and/or hexanol, water, salt and cyclohexane. Depending on the concentrations of the constituent parts, this system may form microemulsion phases and

  8. Phase diagram of a system of hard ellipsoids

    NARCIS (Netherlands)

    Frenkel, D.; Mulder, B.M.; McTaque, J.P.

    1984-01-01

    The phase diagram of a system of hard ellipsoids of revolution was investigated by means of constant-pressure Monte Carlo simulation. Prolate as well as oblate ellipsoids were considered. The results for the isotherms of the system at several different values of the length-to-breadth ratio are prese

  9. Theory of interfacial phase transitions in surfactant systems

    Science.gov (United States)

    Shukla, K. P.; Payandeh, B.; Robert, M.

    1991-06-01

    The spin-1 Ising model, which is equivalent to the three-component lattice gas model, is used to study wetting transitions in three-component surfactant systems consisting of an oil, water, and a nonionic surfactant. Phase equilibria, interfacial profiles, and interfacial tensions for three-phase equilibrium are determined in mean field approximation, for a wide range of temperature and interaction parameters. Surfactant interaction parameters are found to strongly influence interfacial tensions, reducing them in some cases to ultralow values. Interfacial tensions are used to determine whether the middle phase, rich in surfactant, wets or does not wet the interface between the oil-rich and water-rich phases. By varying temperature and interaction parameters, a wetting transition is located and found to be of the first order. Comparison is made with recent experimental results on wetting transitions in ternary surfactant systems.

  10. Three-Phase Load Flow for Unbalanced Systems.

    Science.gov (United States)

    Chang, Yih-Ping

    Traditionally, transmission systems are assumed to be balanced in power system analysis. A single phase positive sequence circuit is used in transmission system load flow analysis to simplify the study. However, when untransposed transmission lines are used in a power system due to economic considerations, space limitation; or when large unbalanced load is on the system; or when an unbalance contingency occurs on the system, this assumption may not hold true. The unbalance condition in some isolated systems are so precarious that disaster can result. One such incident occurred on a generator unit of the third nuclear power plant of Taipower in 1985. In that particular case, the turbine blades were broken and a spark ignited the liquid hydrogen when the blade vibration resonated with the 120.5 Hz rotor current. One cause of this rotor current generation is system unbalance. The unbalanced three-phase load flow program is needed in today's power system analysis. An advanced three-phase unbalanced transmission load flow program, capable of locating the unbalanced problem of large electric network systems, was proposed to be developed and tested in this research. Features of this program include simultaneous power flow of multiple voltage levels on an individual phase basis; PV bus generator, cogenerator, transformer simulation, and load modeling. It is found that delta-grounded wye step-up transformer reduces the convergence speed greatly. When too many delta-grounded wye step-up transformers exist in a large scale system and a quick approximate result of the unbalance conditions is needed, these step-up transformers can be substituted by grounded-wye to grounded-wye type transformers. This is tested on a Taipower system case which included 345KV, 161KV and 69KV feeders, network transformers, 34 PV bus generators and 188 three-phase buses. Impending unbalance problems in Taipower system were located. When not too many delta-grounded wye type transformers are in the

  11. Phase equilibria in polydisperse nonadditive hard-sphere systems.

    Science.gov (United States)

    Paricaud, Patrice

    2008-08-01

    Colloidal particles naturally exhibit a size polydispersity that can greatly influence their phase behavior in solution. Nonadditive hard-sphere (NAHS) mixtures are simple and well-suited model systems to represent phase transitions in colloid systems. Here, we propose an analytical equation of state (EOS) for NAHS fluid mixtures, which can be straightforwardly applied to polydisperse systems. For positive values of the nonadditivity parameter Delta the model gives accurate predictions of the simulated fluid-fluid coexistence curves and compressibility factors. NPT Monte Carlo simulations of the mixing properties of the NAHS symmetric binary mixture with Delta>0 are reported. It is shown that the enthalpy of mixing is largely positive and overcomes the positive entropy of mixing when the pressure is increased, leading to a fluid-fluid phase transition with a lower critical solution pressure. Phase equilibria in polydisperse systems are predicted with the model by using the density moment formalism [P. Sollich, Adv. Chem. Phys. 116, 265 (2001)]. We present predictions of the cloud and shadow curves for polydisperse NAHS systems composed of monodisperse spheres and polydisperse colloid particles. A fixed nonadditivity parameter Delta > 0 is assumed between the monodisperse and polydisperse spheres, and a Schulz distribution is used to represent the size polydispersity. Polydispersity is found to increase the extent of the immiscibility region. The predicted cloud and shadow curves depend dramatically on the upper cutoff diameter sigmac of the Schulz distribution, and three-phase equilibria can occur for large values of sigmac.

  12. An automated two-phase system for hydrogel microbead production.

    Science.gov (United States)

    Coutinho, Daniela F; Ahari, Amir F; Kachouie, Nezamoddin N; Gomes, Manuela E; Neves, Nuno M; Reis, Rui L; Khademhosseini, Ali

    2012-09-01

    Polymeric beads have been used for protection and delivery of bioactive materials, such as drugs and cells, for different biomedical applications. Here, we present a generic two-phase system for the production of polymeric microbeads of gellan gum or alginate, based on a combination of in situ polymerization and phase separation. Polymer droplets, dispensed using a syringe pump, formed polymeric microbeads while passing through a hydrophobic phase. These were then crosslinked, and thus stabilized, in a hydrophilic phase as they crossed through the hydrophobic-hydrophilic interface. The system can be adapted to different applications by replacing the bioactive material and the hydrophobic and/or the hydrophilic phases. The size of the microbeads was dependent on the system parameters, such as needle size and solution flow rate. The size and morphology of the microbeads produced by the proposed system were uniform, when parameters were kept constant. This system was successfully used for generating polymeric microbeads with encapsulated fluorescent beads, cell suspensions and cell aggregates proving its ability for generating bioactive carriers that can potentially be used for drug delivery and cell therapy.

  13. Nonadiabatic Geometric Phase in Composite Systems and Its Subsystem

    Institute of Scientific and Technical Information of China (English)

    LI Xin

    2008-01-01

    We point out that the time-dependent gauge transformation technique may be effective in investigating the nonadiabatic geometric phase of a subsystem in a composite system. As an example, we consider two uniaxially coupled spin -1/2 particles with one of particles driven by rotating magnetic field. The influences of coupling and precession frequency of the magnetic field on geometric phase are also discussed in detail.

  14. Polarization-dependent phase locking in stimulated Brillouin scattering systems.

    Science.gov (United States)

    Hua, X; Falk, J

    1993-10-20

    Measurements of the mutual coherence of the output beams from a seeded, two-pump-beam, stimulated Brillouin scattering system are reported. Mutual coherence depends on the relative polarizations of the pump beams and the seed beam. A seed beam can phase-lock the Stokes outputs even if the pump beams are orthogonally polarized. Four-wave mixing is responsible for this phase locking.

  15. PHASE NOISE COMPARISON OF SHORT PULSE LASER SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Shukui Zhang; Stephen Benson; John Hansknecht; David Hardy; George Neil; Michelle D. Shinn

    2006-08-27

    This paper describes phase noise measurements of several different laser systems that have completely different gain media and configurations including a multi-kW free-electron laser. We will focus on state-of-the-art short pulse lasers, especially drive lasers for photocathode injectors. Phase noise comparison of the FEL drive laser, electron beam and FEL laser output also will be presented.

  16. Phase Noise Comparision of Short Pulse Laser Systems

    Energy Technology Data Exchange (ETDEWEB)

    S. Zhang; S. V. Benson; J. Hansknecht; D. Hardy; G. Neil; Michelle D. Shinn

    2006-12-01

    This paper describes the phase noise measurement on several different mode-locked laser systems that have completely different gain media and configurations including a multi-kW free-electron laser. We will focus on the state of the art short pulse lasers, especially the drive lasers for photocathode injectors. A comparison between the phase noise of the drive laser pulses, electron bunches and FEL pulses will also be presented.

  17. Quantum phase transitions in Bose-Fermi systems

    CERN Document Server

    Petrellis, D; Iachello, F

    2011-01-01

    Quantum phase transitions in a system of N bosons with angular momentum L=0,2 (s,d) and a single fermion with angular momentum j are investigated both classically and quantum mechanically. It is shown that the presence of the odd fermion strongly influences the location and nature of the phase transition, especially the critical value of the control parameter at which the phase transition occurs. Experimental evidence for the U(5)-SU(3) (spherical to axially-deformed) transition in odd-even nuclei is presented.

  18. AC propulsion system for an electric vehicle, phase 2

    Science.gov (United States)

    Slicker, J. M.

    1983-01-01

    A second-generation prototype ac propulsion system for a passenger electric vehicle was designed, fabricated, tested, installed in a modified Mercury Lynx vehicle and track tested at the Contractor's site. The system consisted of a Phase 2, 18.7 kw rated ac induction traction motor, a 192-volt, battery powered, pulse-width-modulated, transistorized inverter packaged for under rear seat installation, a 2-axis, 2-speed, automatically-shifted mechanical transaxle and a microprocessor-based powertrain/vehicle controller. A diagnostics computer to assist tuning and fault finding was fabricated. Dc-to-mechanical-system efficiency varied from 78% to 82% as axle speed/torque ranged from 159 rpm/788 nm to 65 rpm/328 nm. Track test efficiency results suggest that the ac system will be equal or superior to dc systems when driving urban cycles. Additional short-term work is being performed under a third contract phase (AC-3) to raise transaxle efficiency to predicted levels, and to improve starting and shifting characteristics. However, the long-term challenge to the system's viability remains inverter cost. A final report on the Phase 2 system, describing Phase 3 modifications, will be issued at the conclusion of AC-3.

  19. DSPI system based on spatial carrier phase shifting technique

    Science.gov (United States)

    Wang, Yonghong; Li, Junrui; Sun, Jianfei; Yang, Lianxiang

    2013-10-01

    Digital Speckle Pattern Interferometry (DSPI) is an optical method for measuring small displacement and deformation. It allows whole field, non-contacting measurement of micro deformation. Traditional Temporal phase shifting has been used for quantitative analyses in DSPI. The technique requires the recording of at least three phase-shifted interferograms, which must be taken sequentially. This can lead to disturbances by thermal and mechanical fluctuations during the required recording time. In addition, fast object deformations cannot be detected. In this paper a DSPI system using Spatial Carrier Phase Shifting (SCPS) technique is introduced, which is useful for extracting quantitative displacement data from the system with only two interferograms. The sensitive direction of this system refers to the illumination direction and observation direction. The frequencies of the spatial carrier relates to the angle between reference light and observation direction. Fourier transform is adopted in the digital evaluation to filter out the frequencies links to the deformation of testing object. The phase is obtained from the complex matrix formed by inverse Fourier transform, and the phase difference and deformation are calculated subsequently. Comparing with conventional temporal phase shifting, the technique can achieve measuring the vibration and transient deformation of testing object. Experiment set-ups and results are presented in this paper, and the experiment results have shown the effectiveness and advantages of the SCPS technique.

  20. Noise-enhanced phase synchronization in time-delayed systems.

    Science.gov (United States)

    Senthilkumar, D V; Shrii, M Manju; Kurths, J

    2012-02-01

    We investigate the phenomenon of noise-enhanced phase synchronization (PS) in coupled time-delay systems, which usually exhibit non-phase-coherent attractors with complex topological properties. As a delay system is essentially an infinite dimensional in nature with multiple characteristic time scales, it is interesting and crucial to understand the interplay of noise and the time scales in achieving PS. In unidirectionally coupled systems, the response system adjust all its time scales to that of the drive, whereas both subsystems adjust their rhythms to a single (main time scale of the uncoupled system) time scale in bidirectionally coupled systems. We find similar effects for both a common and an independent additive Gaussian noise.

  1. The Application of Phase Type Distributions for Modelling Queuing Systems

    Directory of Open Access Journals (Sweden)

    EIMUTIS VALAKEVICIUS

    2007-12-01

    Full Text Available Queuing models are important tools for studying the performance of complex systems, but despite the substantial queuing theory literature, it is often necessary to use approximations in the case the system is nonmarkovian. Phase type distribution is by now indispensable tool in creation of queuing system models. The purpose of this paper is to suggest a method and software for evaluating queuing approximations. A numerical queuing model with priorities is used to explore the behaviour of exponential phase-type approximation of service-time distribution. The performance of queuing systems described in the event language is used for generating the set of states and transition matrix between them. Two examples of numerical models are presented – a queuing system model with priorities and a queuing system model with quality control.

  2. Complete Phase Diagrams for a Holographic Superconductor/Insulator System

    CERN Document Server

    Horowitz, Gary T

    2010-01-01

    The gravitational dual of an insulator/superconductor transition driven by increasing the chemical potential has recently been constructed. However, the system was studied in a probe limit and only a part of the phase diagram was obtained. We include the backreaction and construct the complete phase diagram for this system. For fixed chemical potential there are typically two phase transitions as the temperature is lowered. Surprisingly, for a certain range of parameters, the system first becomes a superconductor and then becomes an insulator as the temperature approaches zero. As a byproduct of our analysis, we also construct the gravitational dual of a Bose-Einstein condensate of glueballs in a confining gauge theory.

  3. The minimization of ac phase noise in interferometric systems

    DEFF Research Database (Denmark)

    Filinski, Ignacy; Gordon, R A

    1994-01-01

    A simple step-by-step procedure, including several novel techniques discussed in the Appendices, is given for minimizing ac phase noise in typical interferometric systems such as two-beam interferometers, holographic setups, four-wave mixers, etc. Special attention is given to index of refraction...... fluctuations, direct mechanical coupling, and acoustic coupling, whose importance in determining ac phase noise in interferometric systems has not been adequately treated. The minimization procedure must be carried out while continuously monitoring the phase noise which can be done very simply by using...... with the optical table will also have to be carefully carried out regardless of the type of interferometric system employed.It is recommended that this be followed by a simple, inexpensive change to a novel type of interferometer discussed in Appendix A which is inherently less sensitive to mechanical vibration...

  4. Gas phase metal cluster model systems for heterogeneous catalysis.

    Science.gov (United States)

    Lang, Sandra M; Bernhardt, Thorsten M

    2012-07-14

    Since the advent of intense cluster sources, physical and chemical properties of isolated metal clusters are an active field of research. In particular, gas phase metal clusters represent ideal model systems to gain molecular level insight into the energetics and kinetics of metal-mediated catalytic reactions. Here we summarize experimental reactivity studies as well as investigations of thermal catalytic reaction cycles on small gas phase metal clusters, mostly in relation to the surprising catalytic activity of nanoscale gold particles. A particular emphasis is put on the importance of conceptual insights gained through the study of gas phase model systems. Based on these concepts future perspectives are formulated in terms of variation and optimization of catalytic materials e.g. by utilization of bimetals and metal oxides. Furthermore, the future potential of bio-inspired catalytic material systems are highlighted and technical developments are discussed.

  5. Low bitrate system design in the presence of phase noise

    Science.gov (United States)

    Haugli, Hans-Christian

    1995-01-01

    There are a number of interesting mobile satellite applications that require the transmission of short packets of data. In the design of such systems one of the challenges is often to minimize the transmitted power to reduce cost, which implies using power efficient low bit-rate modulation and coding methods. PSK systems can be very power efficient, but at low bit-rates the carrier recovery circuits can be sensitive to oscillator phase noise. In this paper we address the problem of determining the lowest bit-rate that can be supported using PSK for a given level of system phase noise. The classical formulas are reviewed, and a method is derived to calculate the minimum C/N(sub 0) required to recover the carrier for CW, BPSK and QPSK signals for a given phase noise level.

  6. Integrated monitoring and surveillance system demonstration project: Phase I accomplishments

    Energy Technology Data Exchange (ETDEWEB)

    Aumeier, S.E.; Walters, B.G.; Crawford, D.C. [and others

    1997-01-15

    The authors present the results of the Integrated Monitoring and Surveillance System (IMSS) demonstration project Phase I efforts. The rationale behind IMSS development is reviewed and progress in each of the 5 basic tasks is detailed. Significant results include decisions to use Echelon LonWorks networking protocol and Microsoft Access for the data system needs, a preliminary design for the plutonium canning system glovebox, identification of facilities and materials available for the demonstration, determination of possibly affected facility documentation, and a preliminary list of available sensor technologies. Recently imposed changes in the overall project schedule and scope are also discussed and budgetary requirements for competition of Phase II presented. The results show that the IMSS demonstration project team has met and in many cases exceeded the commitments made for Phase I deliverables.

  7. Studies in Three Phase Gas-Liquid Fluidised Systems

    Science.gov (United States)

    Awofisayo, Joyce Ololade

    1992-01-01

    Available from UMI in association with The British Library. The work is a logical continuation of research started at Aston some years ago when studies were conducted on fermentations in bubble columns. The present work highlights typical design and operating problems that could arise in such systems as waste water, chemical, biochemical and petroleum operations involving three-phase, gas-liquid -solid fluidisation; such systems are in increasing use. It is believed that this is one of few studies concerned with "true" three-phase, gas-liquid-solid fluidised systems, and that this work will contribute significantly to closing some of the gaps in knowledge in this area. The research work was experimentally based and involved studies of the hydrodynamic parameters, phase holdups (gas and solid), particle mixing and segregation, and phase flow dynamics (flow regime and circulation patterns). The studies have focused particularly on the solid behaviour and the influence of properties of solids present on the above parameters in three-phase, gas-liquid-solid fluidised systems containing single particle components and those containing binary and ternary mixtures of particles. All particles were near spherical in shape and two particle sizes and total concentration levels were used. Experiments were carried out in two- and three-dimensional bubble columns. Quantitative results are presented in graphical form and are supported by qualitative results from visual studies which are also shown as schematic diagrams and in photographic form. Gas and solid holdup results are compared for air-water containing single, binary and ternary component particle mixtures. It should be noted that the criteria for selection of the materials used are very important if true three-phase fluidisation is to be achieved: this is very evident when comparing the results with those in the literature. The fluid flow and circulation patterns observed were assessed for validation of the generally

  8. Zipf's law emerges asymptotically during phase transitions in communicative systems

    CERN Document Server

    Khomtchouk, Bohdan B

    2016-01-01

    Zipf's law predicts a power-law relationship between word rank and frequency in language communication systems, and is widely reported in texts yet remains enigmatic as to its origins. Computer simulations have shown that language communication systems emerge at an abrupt phase transition in the fidelity of mappings between symbols and objects. Since the phase transition approximates the Heaviside or step function, we show that Zipfian scaling emerges asymptotically at high rank based on the Laplace transform which yields $(1/r)(1-e^{-r})$, where $r$ denotes rank. We thereby demonstrate that Zipf's law gradually emerges from the moment of phase transition in communicative systems. We show that this power-law scaling behavior explains the emergence of natural languages at phase transitions. We find that the emergence of Zipf's law during language communication suggests that the use of rare words in a lexicon (i.e., high $r$) is critical for the construction of an effective communicative system at the phase tra...

  9. Pwm Control Strategy For Controlling Of Parallel Rectifiers In Single Phase To Three Phase Drive System

    Directory of Open Access Journals (Sweden)

    Ramakrishna Manohar Anaparthi

    2014-12-01

    Full Text Available This paper explains that how to develop and design, control of single phase to three phase drive system. The proposed topology of drive system consisting of two parallel connected rectifiers, inverter and induction motor, connected through inductor and capacitor, where used to produce balanced output to the motor drive. The main objective of this proposed method is to reduce the circulating currents and harmonic distortions at the converter input side, here the control strategy of drive system is PWM (pulse width modulations techniques control strategy, the proposed topology also provides fault compensation in the case of short circuit faults and failure of switches for uninterrupted Power supplies. We also develop and simulate the MATLAB models for proposed drive system, by using MATLAB/ Simulink the output results simulate and observed.

  10. Vector Modulator for Phase Shifting in Passive Beamforming Wireless Systems

    Directory of Open Access Journals (Sweden)

    P.Sampath,

    2010-05-01

    Full Text Available This paper proposes vector modulator for changing the phase of a signal in passive beamforming system. Vector modulator is used to perform a phase shift function with added benefit of amplitude control. It is used to improve the directivity of RF waves in Wireless systems. Vector modulator is implemented for a center frequency of 902.5 MHz. The simulation is performed for individual blocks of the vector modulator and for vector modulator with JFET and MOSFET as controlling device in the variable attenuator of the vector modulator.

  11. Phase and Complete Synchronizations in Time-Delay Systems

    Science.gov (United States)

    Senthilkumar, D. V.; Manju Shrii, M.; Kurths, J.

    2013-01-01

    Synchronization is a fundamental nonlinear phenomenon that has been intensively investigated during a couple of decades. Recently, synchronization of time-delay systems with or without delay coupling and even synchronization of low-dimensional dynamical systems described by ordinary differential equations and maps with delay coupling have become an active area of research in view of its potential applications. In this article, we provide an overview of our recent results on phase synchronization in time-delay systems, which usually exhibits hyperchaotic attractors with complex topological properties, noise-enhanced phase and noise-induced complete synchronizations in time-delay systems. Further, we demonstrate the phenomena of delay-enhanced and delay-induced stable synchronous chaos in a delay coupled network of time continuous dynamical system using the framework of master stability formalism (MSF) for the first time.

  12. Interstitially stabilized phases in the zirconium-nickel system

    Energy Technology Data Exchange (ETDEWEB)

    MacKay, R.A.

    1993-07-01

    Addition of nonmetal interstitial atoms to Zr-Ni compounds has resulted in several new phases. A single-crystal x-ray study was carried out for Zr{sub 3}NiO. Zr{sub 4}Ni{sub 2}O is a high- temperature phase, forming in samples annealed at 1250 C. Huekel band calculations led to prediction and confirmation of additional phases in more electron rich systems. Other phases studied by XRD are Zr{sub 6}Ni{sub 4}Ti{sub 2}O{sub 0.6}, Nb{sub 6}Ni{sub 6}O, and Nb{sub 6}Ni{sub 4}Ta{sub 2}O{sub 2}. Phases identified by powder diffraction are Nb{sub 4}Ni{sub 2}O, Zr{sub 4}Cu{sub 2}O, and Zr{sub 6}Co{sub 4}Ti{sub 2}O. New Zr kappa phases in space group P6s{sub 3}/mmc were found: Zr{sub 9}Mo{sub 4}SO{sub x} and Zr{sub 9}W{sub 4}(S,Ni)O{sub 3}. A new structure type was discovered with Zr{sub 6}Ni{sub 6}TiSiO{sub 1.8}. In all these interstitially stabilized phases, O is coordinated in Zr octahedral; there are no Ni-O interactions.

  13. Quantum Phase Transitions in Conventional Matrix Product Systems

    Science.gov (United States)

    Zhu, Jing-Min; Huang, Fei; Chang, Yan

    2017-02-01

    For matrix product states(MPSs) of one-dimensional spin-1/2 chains, we investigate a new kind of conventional quantum phase transition(QPT). We find that the system has two different ferromagnetic phases; on the line of the two ferromagnetic phases coexisting equally, the system in the thermodynamic limit is in an isolated mediate-coupling state described by a paramagnetic state and is in the same state as the renormalization group fixed point state, the expectation values of the physical quantities are discontinuous, and any two spin blocks of the system have the same geometry quantum discord(GQD) within the range of open interval (0,0.25) and the same classical correlation(CC) within the range of open interval (0,0.75) compared to any phase having no any kind of correlation. We not only realize the control of QPTs but also realize the control of quantum correlation of quantum many-body systems on the critical line by adjusting the environment parameters, which may have potential application in quantum information fields and is helpful to comprehensively and deeply understand the quantum correlation, and the organization and structure of quantum correlation especially for long-range quantum correlation of quantum many-body systems.

  14. Accurate parameter estimation for unbalanced three-phase system.

    Science.gov (United States)

    Chen, Yuan; So, Hing Cheung

    2014-01-01

    Smart grid is an intelligent power generation and control console in modern electricity networks, where the unbalanced three-phase power system is the commonly used model. Here, parameter estimation for this system is addressed. After converting the three-phase waveforms into a pair of orthogonal signals via the α β-transformation, the nonlinear least squares (NLS) estimator is developed for accurately finding the frequency, phase, and voltage parameters. The estimator is realized by the Newton-Raphson scheme, whose global convergence is studied in this paper. Computer simulations show that the mean square error performance of NLS method can attain the Cramér-Rao lower bound. Moreover, our proposal provides more accurate frequency estimation when compared with the complex least mean square (CLMS) and augmented CLMS.

  15. Three-phase multilevel solar inverter for motor drive system

    Science.gov (United States)

    Bhasagare, Mayuresh P.

    This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.

  16. Response of phase Doppler anemometer systems to nonspherical droplets.

    Science.gov (United States)

    Damaschke, N; Gouesbet, G; Gréhan, G; Mignon, H; Tropea, C

    1998-04-01

    The Phase Doppler Anemometer (PDA) technique measures particle diameter assuming sphericity. A means for detecting nonsphericity has usually been implemented in commercial PDA systems to avoid sizing errors if the sphericity assumption is not valid. In the present research the response of standard and planar PDA systems is examined experimentally in more detail by passing nonspherical droplets of known shape through the measurement volume. The effectiveness of nonsphericity detection schemes can be evaluated, and furthermore the influence of the droplet oscillations on the frequency and phase evolution of individual signals can be quantified. The light scattering from such particles has been simulated by using geometric optics, and the computed response of standard and planar PDA systems agrees well with the experimental observations. We conclude with some remarks concerning the possibilities of characterizing the nonsphericity with PDA systems.

  17. Nanoscale effects on thermodynamics and phase equilibria in oxide systems.

    Science.gov (United States)

    Navrotsky, Alexandra

    2011-08-22

    Because different solid materials (phases) have different surface energies, equilibria among them will be significantly affected by particle size. This Minireview summarizes experimental (calorimetric) data for the surface energies of oxides and discusses shifts in the stability of polymorphs, the thermodynamics of hydration, and oxidation-reduction reactions in nanoscale oxide systems.

  18. Phase-contrast microfocus X-ray system

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Henrique S.; Pereira, Gabriela R.; Oliveira, Davi F.; Lopes, Ricardo T. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia (COPPE). Lab. de Instrumentacao Nuclear]. E-mails: henrique@lin.ufrj.br; gabriela@lin.ufrj.br; davi@lin.ufrj.br; ricardo@lin.ufrj.br

    2007-07-01

    A phase-contrast X-ray system was developed using a microfocus source. This system uses a highly coherent cone-beam with ten micrometers of minimal focal spot size in a free-space propagation method to obtain phase contrast imaging (PCI). The phase contrast technique relies on its ability to record intensity data which contains information on the X-ray's phase shift. In this technique, the contrast is obtained through refraction, differing from the conventional techniques that use the X-ray attenuation. The system was developed at the Nuclear Instrumentation Laboratory (LIN), COPPE/UFRJ, and it utilizes a high-resolution image plate as a detector. This image plate has a high energy-efficiency in low energy. The results showed that the system allows obtaining high contrast images with less than fifty micrometers of resolution for low density samples and it can be used in several areas, mainly in biology, medical physics and in applications with composites materials. (author)

  19. Phase Change Permeation Technology For Environmental Control Life Support Systems

    Science.gov (United States)

    Wheeler, Raymond M.

    2014-01-01

    Use of a phase change permeation membrane (Dutyion [Trademark]) to passively and selectively mobilize water in microgravity to enable improved water recovery from urine/brine for Environment Control and Life Support Systems (ECLSS) and water delivery to plans for potential use in microgravity.

  20. Wigner Functions for the Bateman System on Noncommutative Phase Space

    Institute of Scientific and Technical Information of China (English)

    HENG Tai-Hua; LIN Bing-Sheng; JING Si-Cong

    2010-01-01

    @@ We study an important dissipation system,I.e.the Bateman model on noncommutative phase space.Using the method of deformation quantization,we calculate the Exp functions,and then derive the Wigner functions and the corresponding energy spectra.

  1. Solidification of ternary systems with a nonlinear phase diagram

    Science.gov (United States)

    Alexandrov, D. V.; Dubovoi, G. Yu.; Malygin, A. P.; Nizovtseva, I. G.; Toropova, L. V.

    2017-02-01

    The directional solidification of a ternary system with an extended phase transition region is theoretically studied. A mathematical model is developed to describe quasi-stationary solidification, and its analytical solution is constructed with allowance for a nonlinear liquidus line equation. A deviation of the liquidus equation from a linear function is shown to result in a substantial change in the solidification parameters.

  2. Phase-modulation transmission system for quantum cryptography.

    Science.gov (United States)

    Mérolla, J M; Mazurenko, Y; Goedgebuer, J P; Porte, H; Rhodes, W T

    1999-01-15

    We describe a new method for quantum key distribution that utilizes phase modulation of sidebands of modulation by use of integrated electro-optic modulators at the transmitting and receiving modules. The system is shown to produce constructive or destructive interference with unity visibility, which should allow quantum cryptography to be carried out with high flexibility by use of conventional devices.

  3. Advanced Turbine System Program: Phase 2 cycle selection

    Energy Technology Data Exchange (ETDEWEB)

    Latcovich, J.A. Jr. [ABB Power Generation, Inc., Midlothian, VA (United States)

    1995-10-01

    The objectives of the Advanced Turbine System (ATS) Phase 2 Program were to define a commercially attractive ATS cycle and to develop the necessary technologies required to meet the ATS Program goals with this cycle. This program is part of an eight-year Department of Energy, Fossil Energy sponsored ATS Program to make a significant improvement in natural gas-fired power generation plant efficiency while providing an environmentally superior and cost-effective system.

  4. Phase Transition of Spin-Peierls Systems with Impurities

    Institute of Scientific and Technical Information of China (English)

    XU Bo-Wei; DING Guo-Hui; YE Fei

    2000-01-01

    The quasi-one-dimensional spin-Peierls(SP) systems with impurities are studied in their bosonized form. The spins of the dimerized state are bounded into singlets with an SP gap, while the impurities of doped systems will induce fluctuations of the coupling strength between the spins at different sites and break some pairs of spin singlets. The doping suppresses the dimerized SP state and induces a Kosterlitz-Thouless phase transition from the dimerized state into the undimerized one.

  5. Noether-Mei Symmetry of Mechanical System in Phase Space

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-Hui; WANG Peng; DING Ning

    2006-01-01

    In this paper, a new kind of symmetry and its conserved quantities of a mechanical system in phase space are studied. The definition of this new symmetry, i.e., a Noether-Mei symmetry, is presented, and the criterion of this symmetry is also given. The Noether conserved quantity and the Mei conserved quantity deduced from the Noether-Mei symmetry of the system are obtained. Finally, two examples are given to illustrate the application of the results.

  6. Data acquisition system for phase-2 KGF proton decay experiment

    Science.gov (United States)

    Krishnaswamy, M. R.; Menon, M. G. K.; Mondal, N. K.; Narasimham, V. S.; Sreekantan, B. V.; Hayashi, Y.; Ito, N.; Kawakami, S.; Miyake, S.

    1985-01-01

    Phase-2 of KGF proton decay experiment using 4000 proportional counters will start operating from middle of 1985. The detection systems, in addition to measuring the time information to an accuracy of 200 n see, also records ionization in the hit counters. It also monitors different characteristics of the counters like pulse height spectrum, pulse width spectrum and counting rate. The acquisition system is discussed.

  7. Phase Diagrams of Instabilities in Compressed Film-Substrate Systems.

    Science.gov (United States)

    Wang, Qiming; Zhao, Xuanhe

    2014-05-01

    Subject to a compressive membrane stress, an elastic film bonded on a substrate can become unstable, forming wrinkles, creases or delaminated buckles. Further increasing the compressive stress can induce advanced modes of instabilities including period-doubles, folds, localized ridges, delamination, and coexistent instabilities. While various instabilities in film-substrate systems under compression have been analyzed separately, a systematic and quantitative understanding of these instabilities is still elusive. Here we present a joint experimental and theoretical study to systematically explore the instabilities in elastic film-substrate systems under uniaxial compression. We use the Maxwell stability criterion to analyze the occurrence and evolution of instabilities analogous to phase transitions in thermodynamic systems. We show that the moduli of the film and the substrate, the film-substrate adhesion strength, the film thickness, and the prestretch in the substrate determine various modes of instabilities. Defects in the film-substrate system can facilitate it to overcome energy barriers during occurrence and evolution of instabilities. We provide a set of phase diagrams to predict both initial and advanced modes of instabilities in compressed film-substrate systems. The phase diagrams can be used to guide the design of film-substrate systems to achieve desired modes of instabilities.

  8. Code-modulated interferometric imaging system using phased arrays

    Science.gov (United States)

    Chauhan, Vikas; Greene, Kevin; Floyd, Brian

    2016-05-01

    Millimeter-wave (mm-wave) imaging provides compelling capabilities for security screening, navigation, and bio- medical applications. Traditional scanned or focal-plane mm-wave imagers are bulky and costly. In contrast, phased-array hardware developed for mass-market wireless communications and automotive radar promise to be extremely low cost. In this work, we present techniques which can allow low-cost phased-array receivers to be reconfigured or re-purposed as interferometric imagers, removing the need for custom hardware and thereby reducing cost. Since traditional phased arrays power combine incoming signals prior to digitization, orthogonal code-modulation is applied to each incoming signal using phase shifters within each front-end and two-bit codes. These code-modulated signals can then be combined and processed coherently through a shared hardware path. Once digitized, visibility functions can be recovered through squaring and code-demultiplexing operations. Pro- vided that codes are selected such that the product of two orthogonal codes is a third unique and orthogonal code, it is possible to demultiplex complex visibility functions directly. As such, the proposed system modulates incoming signals but demodulates desired correlations. In this work, we present the operation of the system, a validation of its operation using behavioral models of a traditional phased array, and a benchmarking of the code-modulated interferometer against traditional interferometer and focal-plane arrays.

  9. Berry Phase Physics in Free and Interacting Fermionic Systems

    CERN Document Server

    Chen, Jing-Yuan

    2016-01-01

    Berry phase plays an important role in many non-trivial phenomena over a broad range of many-body systems. In this thesis we focus on the Berry phase due to the change of the particles' momenta, and study its effects in free and interacting fermionic systems. We start with reviewing the semi-classical kinetic theory with Berry phase for a non-interacting ensemble of fermions -- a Berry Fermi gas -- which might be far-from-equilibrium. We particularly review the famous Berry phase contribution to the anomalous Hall current. We then provide a concrete and general path integral derivation for the semi-classical theory. Then we turn to the specific example of Weyl fermion, which exhibits the profound quantum phenomenon of chiral anomaly; we review how this quantum effect, and its closely related chiral magnetic effect and chiral vortical effect, arise from Berry phase in the semi-classical kinetic theory. We also discuss how Lorentz symmetry in the kinetic theory of Weyl fermion, seemly violated by the Berry phas...

  10. Phase fronts and synchronization patterns in forced oscillatory systems

    Directory of Open Access Journals (Sweden)

    Ehud Meron

    2000-01-01

    Full Text Available This is a review of recent studies of extended oscillatory systems that are subjected to periodic temporal forcing. The periodic forcing breaks the continuous time translation symmetry and leaves a discrete set of stable uniform phase states. The multiplicity of phase states allows for front structures that shift the oscillation phase by π/n where n=1,2,…, hereafter π/n-fronts. The main concern here is with front instabilities and their implications on pattern formation. Most theoretical studies have focused on the 2:1 resonance where the system oscillates at half the driving frequency. All front solutions in this case are π-fronts. At high forcing strengths only stationary fronts exist. Upon decreasing the forcing strength the stationary fronts lose stability to pairs of counter-propagating fronts. The coexistence of counter-propagating fronts allows for traveling domains and spiral waves. In the 4:1 resonance stationary π-fronts coexist with π/2-fronts. At high forcing strengths the stationary π-fronts are stable and standing two-phase waves, consisting of successive oscillatory domains whose phases differ by π,, prevail. Upon decreasing the forcing strength the stationary π-fronts lose stability and decompose into pairs of propagating π/2-fronts. The instability designates a transition from standing two-phase waves to traveling four-phase waves. Analogous decomposition instabilities have been found numerically in higher 2n:1 resonances. The available theory is used to account for a few experimental observations made on the photosensitive Belousov–Zhabotinsky reaction subjected to periodic illumination. Observations not accounted for by the theory are pointed out.

  11. Two-phase flow instability in a parallel multichannel system

    Institute of Scientific and Technical Information of China (English)

    HOU Suxia

    2009-01-01

    The two-phase flow instabilities observed in through parallel multichannel can be classified into three types, of which only one is intrinsic to parallel multichannel systems. The intrinsic instabilities observed in parallel multichannel system have been studied experimentally. The stable boundary of the flow in such a parallel-channel system are sought, and the nature of inlet flow oscillation in the unstable region has been examined experimentally under various conditions of inlet velocity, heat flux, liquid temperature, cross section of channel and entrance throttling. The results show that parallel multichannel system possess a characteristic oscillation that is quite independent of the magnitude and duration of the initial disturbance, and the stable boundary is influenced by the characteristic frequency of the system as well as by the exit quality when this is low, and upon raising the exit quality and reducing the characteristic frequency, the system increases its instability, and entrance throttling effectively contributes to stabilization of the system.

  12. Collectivity, Phase Transitions and Exceptional Points in Open Quantum Systems

    CERN Document Server

    Heiss, W D; Rotter, I

    1998-01-01

    Phase transitions in open quantum systems, which are associated with the formation of collective states of a large width and of trapped states with rather small widths, are related to exceptional points of the Hamiltonian. Exceptional points are the singularities of the spectrum and eigenfunctions, when they are considered as functions of a coupling parameter. In the present paper this parameter is the coupling strength to the continuum. It is shown that the positions of the exceptional points (their accumulation point in the thermodynamical limit) depend on the particular type and energy dependence of the coupling to the continuum in the same way as the transition point of the corresponding phase transition.

  13. Phase reconstruction from intensity measurements in linear systems.

    Science.gov (United States)

    Bastiaans, Martin J; Wolf, Kurt Bernardo

    2003-06-01

    The phase of a signal at a plane is reconstructed from the intensity profiles at two close parallel screens connected by a small abcd canonical transform; this applies to propagation along harmonic and repulsive fibers and in free media. We analyze the relationship between the local spatial frequency (the signal phase derivative) and the derivative of the squared modulus of the signal under a one-parameter canonical transform with respect to the parameter. We thus generalize to all linear systems the results that have been obtained separately for Fresnel and fractional Fourier transforms.

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

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni;

    2011-01-01

    phase boost converter is applied to improve the performance of this motor. It is easy to generate a double dclink voltage and dc-link voltage and switch both of them. The voltage of boost capacitor is self balance, so the protective circuit is not need to consider. The fast excitation mode helps hybrid...... SRM reduce the negative torque before zero-crossing point of torque curve, and build desired phase current to generate more power. Some experimental results are done to verify the performance of proposed hybrid SRM drive system....

  15. FGD systems: What utilities chose in phase 1 and what they might choose in phase 2

    Energy Technology Data Exchange (ETDEWEB)

    South, D.W.; Bailey, K.A.

    1995-07-01

    Title IV (acid rain) of the Clean Air Act Amendments of 1990 is imposing new limitations on the emission of sulfur dioxide (SO{sub 2}) and nitrogen oxides (NO{sub x}) from electric power plants. The Act requires utilities to develop compliance plans to reduce these emissions, and indications are that these plans will dramatically alter traditional operating procedures. A key provision of the SO{sub 2} control program defined in Title IV is the creation of a system of emission allowances, with utilities having, the option of complying by adjusting system emissions and allowance holdings. The central focus of this paper is the identification of sulfur dioxide (SO{sub 2}) control options being implemented by the electric utility industry, current compliance trends, synergistic control issues and a discussion of the implications of Phase I decisions for Phase II.

  16. Brayton isotope power system, phase I. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-28

    The Phase I program resulted in the development and ground demonstration of a dynamic power conversion system. The two key contractual objectives of 25% conversion efficiency and 1000 h of endurance testing were successfully met. As a result of the Phase I effort, the BIPS is a viable candidate for further development into a flight system capable of sustained operation in space. It represents the only known dynamic space power system to demonstrate the performance and endurance coupled with the simplicity necessary for reliable operation. This final report follows thirty-five monthly reports. For expediency, it makes liberal use of referenced documents which have been submitted to DOE during the course of the program.

  17. Enantiomeric 3-chloromandelic acid system: binary melting point phase diagram, ternary solubility phase diagrams and polymorphism.

    Science.gov (United States)

    Le Minh, Tam; von Langermann, Jan; Lorenz, Heike; Seidel-Morgenstern, Andreas

    2010-09-01

    A systematic study of binary melting point and ternary solubility phase diagrams of the enantiomeric 3-chloromandelic acid (3-ClMA) system was performed under consideration of polymorphism. The melting point phase diagram was measured by means of thermal analysis, that is, using heat-flux differential scanning calorimetry (DSC). The results reveal that 3-ClMA belongs to the racemic compound-forming systems. Polymorphism was found for both the enantiomer and the racemate as confirmed by X-ray powder diffraction analysis. The ternary solubility phase diagram of 3-ClMA in water was determined between 5 and 50 degrees C by the classical isothermal technique. The solubilities of the pure enantiomers are extremely temperature-dependent. The solid-liquid equilibria of racemic 3-ClMA are not trivial due to the existence of polymorphism. The eutectic composition in the chiral system changes as a function of temperature. Further, solubility data in the alternative solvent toluene are also presented.

  18. Analysis of SDFT based phase detection system for grid synchronization of distributed generation systems

    Directory of Open Access Journals (Sweden)

    B. Chitti Babu

    2014-12-01

    Full Text Available A fast and exact detection of phase and fundamental frequency of grid voltage/current is essential for calculating accurate reference signal in order to implement the control algorithm of inverter-interfaced distributed generation (DG system and realize precise harmonic compensation. However, the methods adapted in the literature based on phase locked loop (PLL exhibits large phase error, be difficult to implement, and their performance is also indistinct under conditions where the grid frequency varies or the supply is distorted with low frequency harmonics. This paper explores an improved phase detection system for DG system based on Sliding Discrete Fourier Transform (SDFT. The proposed SDFT based phase detection shows a robust phase tracking capability with fast transient response under adverse situation of the grid. Moreover, SDFT phase detection system is more efficient as it requires small number of operations to extract a single frequency component, thereby reducing computational complexity and simpler than DFT. The superior performance of proposed SDFT phase detection system is analyzed and the obtained results are compared with Discrete Fourier Transform (DFT filtering to confirm the feasibility of the study under different grid environment such as high frequency harmonic injection, frequency deviation, and phase variation etc.

  19. Dissipation-driven quantum phase transitions in collective spin systems

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, S [Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria); Parkins, A S [Department of Physics, University of Auckland, Private Bag 92019, Auckland (New Zealand)], E-mail: smor161@aucklanduni.ac.nz

    2008-10-14

    We consider two different collective spin systems subjected to strong dissipation-on the same scale as interaction strengths and external fields-and show that either continuous or discontinuous dissipative quantum phase transitions can occur as the dissipation strength is varied. First, we consider a well-known model of cooperative resonance fluorescence that can exhibit a second-order quantum phase transition, and analyse the entanglement properties near the critical point. Next, we examine a dissipative version of the Lipkin-Meshkov-Glick interacting collective spin model, where we find that either first- or second-order quantum phase transitions can occur, depending only on the ratio of the interaction and external field parameters. We give detailed results and interpretation for the steady-state entanglement in the vicinity of the critical point, where it reaches a maximum. For the first-order transition we find that the semiclassical steady states exhibit a region of bistability. (fast track communication)

  20. Phase space view of quantum mechanical systems and Fisher information

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, Á., E-mail: anagy@madget.atomki.hu

    2016-06-17

    Highlights: • Phase-space Fisher information coming from the canonical distribution is derived for the ground state of quantum mechanical systems. • Quantum mechanical phase-space Fisher information contains an extra term due to the position dependence of the temperature. • A complete analogy to the classical case is demonstrated for the linear harmonic oscillator. - Abstract: Pennini and Plastino showed that the form of the Fisher information generated by the canonical distribution function reflects the intrinsic structure of classical mechanics. Now, a quantum mechanical generalization of the Pennini–Plastino theory is presented based on the thermodynamical transcription of the density functional theory. Comparing to the classical case, the phase-space Fisher information contains an extra term due to the position dependence of the temperature. However, for the special case of constant temperature, the expression derived bears resemblance to the classical one. A complete analogy to the classical case is demonstrated for the linear harmonic oscillator.

  1. Study on phase synchronization of stochastic chaotic system

    Institute of Scientific and Technical Information of China (English)

    Yang Xiao-Li; Xu Wei

    2008-01-01

    This paper detects and characterizes the diverse roles played by bounded noise in chaotic phase synchronization (CPS) of weakly coupled nonlinear stochastic systems. Analysis of a paradigmatic model of two bidirectional coupled three-level food chains is carried out by various statistical measures such as Shannon entropy and mutual information. The results indicate that inside the synchronous regime, CPS is considerably reduced under the influence of bounded noise; near the onset of phase synchronization, temporal phase locking is diversely changed with the increase of noise, i.e., either weak or strong noise also degrades the degree of CPS, while intermediate noise enhances CPS remarkably, and an optimal noise intensity is detected that maximizes the enhancement.

  2. Intelligent System for Diagnosis of a Three-Phase Separator

    Directory of Open Access Journals (Sweden)

    Irina Ioniţă

    2016-03-01

    Full Text Available Intelligent systems for diagnosis have been used in a variety of domains: financial evaluation, credit scoring problem, identification of software and hardware problems of mechanical and electronic equipment, medical diagnosis, fault detection in gas-oil production plants etc. The goal of diagnosis systems is to classify the observed symptoms as being caused by some diagnosis class while advising systems perform such a classification and offer corrective remedies (recommendations. The current paper discuss the opportunity to combine more intelligent techniques and methodologies (intelligent agents, data mining and expert systems to increase the accuracy of results obtained from the diagnosis of a three-phase separator. The results indicate that the diagnosis hybrid system benefits from the advantages of each module component: intelligent agent module, data mining module and expert system module.

  3. Intelligent System for Diagnosis of a Three-Phase Separator

    Directory of Open Access Journals (Sweden)

    Irina Ioniţă

    2016-03-01

    Full Text Available Intelligent systems for diagnosis have been used in a variety of domains: financial evaluation, credit scoring problem, identification of software and hardware problems of mechanical and electronic equipment, medical diagnosis, fault detection in gas-oil production plants etc. The goal of diagnosis systems is to classify the observed symptoms as being caused by some diagnosis class while advising systems perform such a classification and offer corrective remedies (recommendations. The current paper discuss the opportunity to combine more intelligent techniques and methodologies (intelligent agents, data mining and expert systems to increase the accuracy of results obtained from the diagnosis of a three-phase separator. The results indicate that the diagnosis hybrid system benefits from the advantages of each module component: intelligent agent module, data mining module and expert system module.

  4. Forest Resource Information System. Phase 3: System transfer report

    Science.gov (United States)

    Mroczynski, R. P. (Principal Investigator)

    1981-01-01

    Transfer of the forest reserve information system (FRIS) from the Laboratory for Applications of Remote Sensing to St. Regis Paper Company is described. Modifications required for the transfer of the LARYS image processing software are discussed. The reformatting, geometric correction, image registration, and documentation performed for preprocessing transfer are described. Data turnaround was improved and geometrically corrected and ground-registered CCT LANDSAT 3 data provided to the user. The technology transfer activities are summarized. An application test performed in order to assess a Florida land acquisition is described. A benefit/cost analysis of FRIS is presented.

  5. Phase change energy storage for solar dynamic power systems

    Science.gov (United States)

    Chiaramonte, F. P.; Taylor, J. D.

    1992-01-01

    This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

  6. A general thermodynamic analysis and treatment of phases and components in the analysis of phase assemblages in multicomponent systems

    Institute of Scientific and Technical Information of China (English)

    HU JiaWen

    2012-01-01

    Systematic thermodynamic analysis reveals that an essential condition for the thermodynamically valid chemographic projections proposed by Greenwood is completely excessive.In other words,the phases or components from which the projection is made need not be pure,nor have their chemical potentials fixed over the whole chemographic diagram.To facilitate the analysis of phase assemblages in multicomponent systems,all phases and components in the system are divided into internal and external ones in terms of their thermodynamic features and roles,where the external phases are those common to all assemblages in the system,and the external components include excess components and the components whose chemical potentials (or relevant intensive properties of components) are used to define the thermodynamic conditions of the system.This general classification overcomes the difficulties and defects in the previous classifications,and is easier to use than the previous ones.According to the above classification,the phase rule is transformed into a new form.This leads to two findings:(1) the degree of freedom of the system under the given conditions is only determined by the internal components and phases; (2) different external phases can be identified conveniently according to the conditions of the system before knowing the real phase relations.Based on the above results,a simple but general approach is proposed for the treatment of phases and components:all external phases and components can be eliminated from the system without affecting the phase relations,where the external components can be eliminated by appropriate chemographic projections.The projections have no restriction on the states of the phases or the chemical potentials of components from which the projections are made.Th e present work can give a unified explanation of the previous treatments of phases and components in the analysis of phase assemblages under various specific conditions.It helps to avoid

  7. Phase transformations and phase equilibria in the Co-Sn-Ti system in the crystallization interval

    Science.gov (United States)

    Fartushna, Iu.; Bulanova, M.; Ayral, R. M.; Tedenac, J. C.; Meleshevich, K.

    2016-12-01

    The Co-Sn-Ti system was studied in the crystallization interval (below 50 at% Sn) by the methods of Scanning Electron Microscopy, microprobe analysis, Differential Thermal Analysis, X-ray diffraction. The liquidus and solidus projections and the melting diagram were constructed. Only Co2TiSn(τ1) ternary compound (Heusler phase-L12) was found in equilibria with the liquid in the concentration interval studied. Taking into account our recent data, the liquidus projection is characterized by the fields of primary crystallization of (βTi), (Co), binary-based phases Ti3Sn, Ti2Sn, Ti5Sn3, Ti6Sn5, Ti2Co, TiCo, TiCo2 (c), TiCo2 (h), TiCo3, βCo3Sn2, CoSn and ternary τ1. The solidus projection is characterized by thirteen three-phase fields, which result from invariant four-phase equilibria, five are of eutectic type (E) and eight of transition type (U) and the existence of one more region Ti2Sn3+βCoSn3+(Sn) in the solidus projection is discussed.

  8. Phase Diagrams for the PEO-LiX Electrolyte System.

    Science.gov (United States)

    1987-01-01

    rather flat, in sharp contrast to previous results. 3.2c PEO- LiBF4 System Pure PEO forms complexes with LiBF , and the subsequent phase diagram for...study; 0 ----NMR(15); 0 -DSC or DTA(7, 10,12); A ---a.c.conductivity(6,10,12); 4- optical microscopy(6). is 350 - (PEO) n- LiBF4 300 (PEO) n-LiCF 3SO 3...the PEO- LiBF4 system IS" , " ATOM RATIO O/Li 50 25 8 4 2 1 250 200 150 1 00 -50I 0 0 0.1 0.2 0.3 0.4 0.5 XLiPF6 -’+’ Figure 6. Phase diagram of the

  9. Phase behavior, formation, and rheology of cubic phase and related gel emulsion in Tween 80/water/oil systems.

    Science.gov (United States)

    Alam, Mohammad Mydul; Ushiyama, Kousuke; Aramaki, Kenji

    2009-01-01

    We investigated the phase behavior, formation, and rheology of the cubic phase (I(1)) and related O/I(1) gel emulsion in water/Tween 80/oil systems using squalane, liquid paraffin (LP), and decane as oil components. In the phase behavior study, the phase sequences were similar for squalane and LP systems, while a lamellar liquid crystal (L(alpha)) was observed for decane system. In all the systems the addition of oil to W(m) or H(1) phase induced the I(1) phase, which can solubilize some amounts of oil followed by the appearance of I(1)+O phase. The formation of the O/I(1) gel emulsion has been studied at a fixed w/s (50/50) and we found that 30 wt% decane, 70 wt% squalane, and 60 wt% LP can form the gel emulsion. The water/Tween 80/squalane system has been taken as a model system to study viscoelastic properties of the I(1) phase and O/I(1) gel emulsion. The I(1) phase shows a typical hard gel cubic structure under the frequency and the values of the complex viscosity, /eta*/ and the elastic modulus, G ' increase with the addition of squalane, which could be due to the neighboring micellar interaction. On the other hand, the decreasing values of the viscoelastic parameters in the O/I(1) gel emulsion simply relate to the volume fraction of the I(1) phase in the system.

  10. Theory of photoinduced phase transitions in itinerant electron systems

    Energy Technology Data Exchange (ETDEWEB)

    Yonemitsu, Kenji [Institute for Molecular Science, Graduate University for Advanced Studies, Okazaki, Aichi 444-8585 (Japan)], E-mail: kxy@ims.ac.jp; Nasu, Keiichiro [Solid State Theory Division, Institute of Materials Structure Science, KEK, Graduate University for Advanced Studies, CREST JST, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)], E-mail: knasu@post.kek.jp

    2008-08-15

    Theoretical progress in the research of photoinduced phase transitions is reviewed with closely related experiments. After a brief introduction of stochastic evolution in statistical systems and domino effects in localized electron systems, we treat photoinduced dynamics in itinerant-electron systems. Relevant interactions are required in the models to describe the fast and ultrafast charge-lattice-coupled dynamics after photoexcitations. First, we discuss neutral-ionic transitions in the mixed-stack charge-transfer complex, TTF-CA. When induced by intrachain charge-transfer photoexcitations, the dynamics of the ionic-to-neutral transition are characterized by a threshold behavior, while those of the neutral-to-ionic transition by an almost linear behavior. The difference originates from the different electron correlations in the neutral and ionic phases. Second, we deal with halogen-bridged metal complexes, which show metal, Mott insulator, charge-density-wave, and charge-polarization phases. The latter two phases have different broken symmetries. The charge-density-wave to charge-polarization transition is much more easily achieved than the reverse transition. This is clarified by considering microscopic charge-transfer processes. The transition from the charge-density-wave to Mott insulator phases and that from the Mott insulator to metal phases proceed much faster than those between the low-symmetry phases. Next, we discuss ultrafast, inverse spin-Peierls transitions in an organic radical crystal and alkali-TCNQ from the viewpoint of intradimer and interdimer charge-transfer excitations. Then, we study photogenerated electrons in the quantum paraelectric perovskite, SrTiO{sub 3}, which are assumed to couple differently with soft-anharmonic phonons and breathing-type high-energy phonons. The different electron-phonon couplings result in two types of polarons, a 'super-paraelectric large polaron' with a quasi-global parity violation, and an &apos

  11. Theory of photoinduced phase transitions in itinerant electron systems

    Science.gov (United States)

    Yonemitsu, Kenji; Nasu, Keiichiro

    2008-08-01

    Theoretical progress in the research of photoinduced phase transitions is reviewed with closely related experiments. After a brief introduction of stochastic evolution in statistical systems and domino effects in localized electron systems, we treat photoinduced dynamics in itinerant-electron systems. Relevant interactions are required in the models to describe the fast and ultrafast charge-lattice-coupled dynamics after photoexcitations. First, we discuss neutral-ionic transitions in the mixed-stack charge-transfer complex, TTF-CA. When induced by intrachain charge-transfer photoexcitations, the dynamics of the ionic-to-neutral transition are characterized by a threshold behavior, while those of the neutral-to-ionic transition by an almost linear behavior. The difference originates from the different electron correlations in the neutral and ionic phases. Second, we deal with halogen-bridged metal complexes, which show metal, Mott insulator, charge-density-wave, and charge-polarization phases. The latter two phases have different broken symmetries. The charge-density-wave to charge-polarization transition is much more easily achieved than the reverse transition. This is clarified by considering microscopic charge-transfer processes. The transition from the charge-density-wave to Mott insulator phases and that from the Mott insulator to metal phases proceed much faster than those between the low-symmetry phases. Next, we discuss ultrafast, inverse spin-Peierls transitions in an organic radical crystal and alkali-TCNQ from the viewpoint of intradimer and interdimer charge-transfer excitations. Then, we study photogenerated electrons in the quantum paraelectric perovskite, SrTiO 3, which are assumed to couple differently with soft-anharmonic phonons and breathing-type high-energy phonons. The different electron-phonon couplings result in two types of polarons, a “super-paraelectric large polaron” with a quasi-global parity violation, and an “off-center-type self

  12. Beam Position and Phase Monitor - Wire Mapping System

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, Heath A [Los Alamos National Laboratory; Shurter, Robert B. [Los Alamos National Laboratory; Gilpatrick, John D. [Los Alamos National Laboratory; Kutac, Vincent G. [Los Alamos National Laboratory; Martinez, Derwin [Los Alamos National Laboratory

    2012-04-10

    The Los Alamos Neutron Science Center (LANSCE) deploys many cylindrical beam position and phase monitors (BPPM) throughout the linac to measure the beam central position, phase and bunched-beam current. Each monitor is calibrated and qualified prior to installation to insure it meets LANSCE requirements. The BPPM wire mapping system is used to map the BPPM electrode offset, sensitivity and higher order coefficients. This system uses a three-axis motion table to position the wire antenna structure within the cavity, simulating the beam excitation of a BPPM at a fundamental frequency of 201.25 MHz. RF signal strength is measured and recorded for the four electrodes as the antenna position is updated. An effort is underway to extend the systems service to the LANSCE facility by replacing obsolete electronic hardware and taking advantage of software enhancements. This paper describes the upgraded wire positioning system's new hardware and software capabilities including its revised antenna structure, motion control interface, RF measurement equipment and Labview software upgrades. The main purpose of the wire mapping system at LANSCE is to characterize the amplitude response versus beam central position of BPPMs before they are installed in the beam line. The wire mapping system is able to simulate a beam using a thin wire and measure the signal response as the wire position is varied within the BPPM aperture.

  13. Universal phase diagram for high-piezoelectric perovskite systems

    NARCIS (Netherlands)

    Cox, D.E.; Noheda, B.; Shirane, G.; Uesu, Y.; Fujishiro, K.; Yamada, Y.

    2001-01-01

    Strong piezoelectricity in perovskite-type PbZn1-xTixO3 (PZT) and Pb(Zn1/3Nb2/3)O3–PbTiO3 (PZN–PT) systems is generally associated with the existence of a morphotropic phase boundary (MPB) separating regions with rhombohedral and tetragonal symmetry. An x-ray study of PZN–9% PT has revealed the pres

  14. Resonant Phase Patterns in a Reaction-Diffusion System

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Anna L.; Bertram, Matthias; Martinez, Karl; Swinney, Harry L.; Ardelea, Alexandre; Carey, Graham F.

    2000-05-01

    Resonance regions similar to the Arnol'd tongues found in single oscillator frequency locking are observed in experiments using a spatially extended periodically forced Belousov-Zhabotinsky system. We identify six distinct 2:1 subharmonic resonant patterns and describe them in terms of the position-dependent phase and magnitude of the oscillations. Some experimentally observed features are also found in numerical studies of a forced Brusselator reaction-diffusion model. (c) 2000 The American Physical Society.

  15. BOA: Asbestos pipe insulation removal robot system. Phase 1

    Energy Technology Data Exchange (ETDEWEB)

    Schempf, H.; Bares, J.E.

    1995-02-01

    The project described in this report targets the development of a mechanized system for safe, cost-efficient and automated abatement of asbestos containing materials used as pipe insulation. Based on several key design criteria and site visits, a proof-of-concept prototype robot system, dubbed BOA, was designed and built, which automatically strips the lagging and insulation from the pipes, and encapsulates them under complete vacuum operation. The system can operate on straight runs of piping in horizontal or vertical orientations. Currently we are limited to four-inch diameter piping without obstacles as well as a somewhat laborious emplacement and removal procedure -- restrictions to be alleviated through continued development. BOA removed asbestos at a rate of 4-5 ft./h compared to 3 ft./h for manual removal of asbestos with a 3-person crew. The containment and vacuum system on BOA was able to achieve the regulatory requirement for airborne fiber emissions of 0.01 fibers/ccm/ 8-hr. shift. This program consists of two phases. The first phase was completed and a demonstration was given to a review panel, consisting of DOE headquarters and site representatives as well as commercial abatement industry representatives. Based on the technical and programmatic recommendations drafted, presented and discussed during the review meeting, a new plan for the Phase II effort of this project was developed. Phase 11 will consist of a 26-month effort, with an up-front 4-month site-, market-, cost/benefit and regulatory study before the next BOA robot (14 months) is built, and then deployed and demonstrated (3 months) at a DOE site (such as Fernald or Oak Ridge) by the beginning of FY`97.

  16. Choice of optical system is critical for the security of double random phase encryption systems

    Science.gov (United States)

    Muniraj, Inbarasan; Guo, Changliang; Malallah, Ra'ed; Cassidy, Derek; Zhao, Liang; Ryle, James P.; Healy, John J.; Sheridan, John T.

    2017-06-01

    The linear canonical transform (LCT) is used in modeling a coherent light-field propagation through first-order optical systems. Recently, a generic optical system, known as the quadratic phase encoding system (QPES), for encrypting a two-dimensional image has been reported. In such systems, two random phase keys and the individual LCT parameters (α,β,γ) serve as secret keys of the cryptosystem. It is important that such encryption systems also satisfy some dynamic security properties. We, therefore, examine such systems using two cryptographic evaluation methods, the avalanche effect and bit independence criterion, which indicate the degree of security of the cryptographic algorithms using QPES. We compared our simulation results with the conventional Fourier and the Fresnel transform-based double random phase encryption (DRPE) systems. The results show that the LCT-based DRPE has an excellent avalanche and bit independence characteristics compared to the conventional Fourier and Fresnel-based encryption systems.

  17. Instantaneous Power Compensation in Three-Phase Systems by Using p-q-r Theory

    DEFF Research Database (Denmark)

    Kim, Hyosung; Blaabjerg, Frede; Bak-Jensen, Birgitte;

    2002-01-01

    Three linearly independent instantaneous powers have been defined in the time domain in three-phase four-wire systems with the use of p-q-r theory. Any three-phase circuit can be transformed into three single-phase circuits by the p-q-r transformation Thus the instantaneous powers in any three-phase...... systems can be analysed as the same way of instantaneous power in single-phase systems.This paper analyses the instantaneous powers spectrally in the frequency domain for single-phase systems and three-phase systems. Each instantaneous power in three-phase systems has its own spectral pattern...... that is characterized by the spectral distribution of the system voltages and currents. The instantaneous power in single-phase systems has its own spectral pattern different from that of three-phase systems.From the spectral analysis of the instantaneous powers, powers are newly defined in the frequency domain...

  18. Nuclear Matter Phase Transition in Infinite and Finite Systems

    Science.gov (United States)

    Terranova, S.; Bonasera, A.

    2005-04-01

    A new "semiclassical" model of the nuclear matter, composed of u, d colored quarks, is proposed. The approach, named Constrained Molecular Dynamics (CoMD) is based on the molecular dynamics simulation of the quarks, which interact through the Richardson's potential, and on a constraint due to Pauli blocking. With a suitable choice of the quark masses, some possible Equation of State (EOS) of the nuclear matter, at temperature equal to zero and finite baryon density, are obtained. These equations of state, not only present some known properties of the nuclear matter, as the Quark-Gluon Plasma (QGP) phase transition, but also shown the existence of a new state, the Exotic Color Clustering (ECC) state, in which cluster of quarks with the same color are formed. Some new quantities, "indicators" of the phase transition, are introduced: three order parameters, Mc2, Mc3, Mc4 defined trough the Gell-Mann matrices λα, and the lifetime of the J/Ψ particle. The behavior of the J/Ψ particle is studied also in the "finite" systems, obtained by expanding the corresponding "infinite" systems. It seems that the dynamics and the finite size effects do not wash completely the phase transition occurred in infinite systems, and the J/Ψ particle is still a good signature.

  19. Phase noise approximation analysis for the OFDM system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The influence of phase noise (PN) present at the access point (AP) and mobile terminator (MT) may degrade the performance in orthogonal frequency division multiplexing (OFDM) system, because the OFDM system is sensitive to the PN.The method of PN approximation based on the PN power spectrum was proposed to combat the influence of the PN present.The idea of the PN cancellation is the PN is approximated for the sum of the different frequency between the AP and the MT as well as Doppler shift supposing that the fixed different frequency during several OFDM symbols are identical, so the variable phase may be considered as the combination of the fixed partition and the random partition.The approximation method is utilized to remove the fixed and the random phase partition so that the signal-to-noise ratio (SNR) may be improved.The analysis and the simulation proposed show that the method may effectively improve the performance of the OFDM system.

  20. Development of Sensors for Ceramic Components in Advanced Propulsion Systems. Phase 2; Temperature Sensor Systems Evaluation

    Science.gov (United States)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1994-01-01

    The 'development of sensors for ceramic components in advanced propulsion systems' program is divided into two phases. The objectives of Phase 1 were to analyze, evaluate and recommend sensor concepts for the measurement of surface temperature, strain and heat flux on ceramic components for advanced propulsion systems. The results of this effort were previously published in NASA CR-182111. As a result of Phase 1, three approaches were recommended for further development: pyrometry, thin-film sensors, and thermographic phosphors. The objective of Phase 2 were to fabricate and conduct laboratory demonstration tests of these systems. Six materials, mutually agreed upon by NASA and Pratt & Whitney, were investigated under this program. This report summarizes the Phase 2 effort and provides conclusions and recommendations for each of the categories evaluated.

  1. Fast Approximate Broadband Phase Retrieval for Segmented Systems

    Science.gov (United States)

    Jurling, Alden S.; Fienup, James R.

    2011-01-01

    Broadband phase retrieval needed when: a) Narrow spectral filters are unavailable. b) Dim sources. c) Low throughput due to misalignment. d) Short exposures times. i.e., Pointing instability (space); and Atmospheric instability (ground based AO). Traditional approach is computationally burdensome for extreme bandwidths. Approximate approach: a) Substitute monochromatic model. b) Blur model and data. Test case performance: a) approx.270x reduction in computational cost for FGS-like test case. b) Good accuracy for monolithic system. c) Acceptable accuracy for segmented systems. i.e., Reduced by diffraction and Reduced by higher order segment model.

  2. Human Systems Integration (HSI) in Acquisition. Acquisition Phase Guide

    Science.gov (United States)

    2009-08-01

    Tools: ● CATIA ● HSI Requirements Guide ● IMPRINT Activities for Each Output: 1.0 Collect domain requirements inputs 1.1 Ensure draft system...Outputs boxes. Tools: ● NHV ● Index of Habitability ● IMPRINT, CATIA , JACK ● HSI Requirements Guide Activities for Each Output: 1.0 Provide...Phase (Inputs) Human Systems Integration Tools: ● IMPRINT ● CATIA ● IPME References: ● DODI 5000.02 & DODD 5000.01 ● DAG ● CJCSI 3170.01 ● AFPD 63

  3. Stability of Phase-modulated Quantum Key Distribution System

    CERN Document Server

    Han, Z F; Gui, Y Z; Guo, G C; Han, Zheng-Fu; Mo, Xiao-Fan; Gui, You-Zhen; Guo, Guang-Can

    2004-01-01

    Phase drift and random fluctuation of interference visibility in double unbalanced M-Z QKD system are observed and distinguished. It has been found that the interference visibilities are influenced deeply by the disturbance of transmission fiber. Theory analysis shows that the fluctuation is derived from the envioronmental disturbance on polarization characteristic of fiber, especially including transmission fiber. Finally, stability conditions of one-way anti-disturbed M-Z QKD system are given out, which provides a theoretical guide in pragmatic anti-disturbed QKD.

  4. A New Reaction-controlled Phase-transfer Catalyst System

    Institute of Scientific and Technical Information of China (English)

    Ming Qiang LI; Xi Gao JIAN; Gui Mei WANG; Yan YU

    2004-01-01

    A new reaction-controlled phase-transfer catalyst system was designed and synthesized. In this system, heteropolytungstate [C7H7N(CH3)3]9PW9O34 was used for catalytic epoxidation of cyclohexene with H2O2 as the oxidant. The conversion of H2O2 was 100% and the yield of cyclohexene oxide was 87.1% based on cyclohexene. Infrared spectra showed that both fresh catalyst and the recovered catalyst do have completely same absorption peak, indicating the structure of catalyst is very stability and can be recycled.

  5. Physics Detector Simulation Facility Phase II system software description

    Energy Technology Data Exchange (ETDEWEB)

    Scipioni, B.; Allen, J.; Chang, C.; Huang, J.; Liu, J.; Mestad, S.; Pan, J.; Marquez, M.; Estep, P.

    1993-05-01

    This paper presents the Physics Detector Simulation Facility (PDSF) Phase II system software. A key element in the design of a distributed computing environment for the PDSF has been the separation and distribution of the major functions. The facility has been designed to support batch and interactive processing, and to incorporate the file and tape storage systems. By distributing these functions, it is often possible to provide higher throughput and resource availability. Similarly, the design is intended to exploit event-level parallelism in an open distributed environment.

  6. Power System Control Study. Phase I. Integrated Control Techniques. Phase II. Detail Design and System Modeling.

    Science.gov (United States)

    1981-03-01

    single engine system. With this hardware, the power flow from the load management (or power distribution) centers to individual utilization equipments...assuming all loads are HVDC ). Other advantages of HVDC are ease of paralleling multiple power sources, ease 114 E-44 w- 00 E-4 z E 4-4 4 CI- >. 00 rL...matrices. There are additional coupling terms present in the case of parallel operation due to currents from two sources flowing through the load . The

  7. EXPERIMENTAL PHASE EQUILIBRIA OF SELECTED BINARY, TERNARY, AND HIGHER ORDER SYSTEMS. PART 4. THE PHASE DIAGRAM W-B-C

    Science.gov (United States)

    system and the mutual solubilities between carbide and boride phases are small. The solid state sections (򒾐C) are characterized by two- phase ... equilibria existing between the phase pairs W2B + W2C, W2B + WC, WC + WB, WB + C, W2B5 + C, W2B5 + B4C, and WB approximately 4 + B4C. The two-phase

  8. PZT Network and Phased Array Lamb Wave Based SHM Systems

    Energy Technology Data Exchange (ETDEWEB)

    Silva, C [Academia da Forca Aerea, Granja do Marques, 2715-021 Pero Pinheiro (Portugal); Rocha, B; Suleman, A, E-mail: cbsilva@emfa.pt [University of Victoria, Department of Mechanical Engineering, PO Box 3055, Stn.CSC, Victoria, BC, V8W 3P6 (Canada)

    2011-07-19

    With the application of newer materials, such as composite materials, and growing complexity and capacity of current aircraft structures, reliably and completely assess the condition of the total structures in real time is then of growing and utmost importance. PZT Network and Phased Array, Lamb wave based Structural Health Monitoring (SHM) systems were developed to be applied to thin panels. The selection of transducers, their size and selected locations for their installation are described. The development and selection of the signal generation and data acquisition systems is also presented in detail. The requirements conducing to the development and selection of these systems are laid and particularly the selection of the actuation signal applied is justified. The development of a damage detection algorithm based in the comparison of the current structural state to a reference state is described, to detect damage reflected Lamb waves. Such method was implemented in software and integrated in the SHM system developed. Subsequently the detection algorithm, based in discrete signals correlation, was further improved by incorporating statistical methods. For phased arrays, a novel damage location algorithm is presented based on the individual sensors response. A visualization method based concurrently in the statistical methods developed and superposition of the different results obtained from a test set was implemented. These tests conducted to the successful and repeatable detection of 1mm damages in a multiple damaged plate with great confidence. Finally, a brief comparison and a hybrid system implementation is presented.

  9. Dynamical tunneling in systems with a mixed phase space

    Energy Technology Data Exchange (ETDEWEB)

    Loeck, Steffen

    2010-04-22

    Tunneling is one of the most prominent features of quantum mechanics. While the tunneling process in one-dimensional integrable systems is well understood, its quantitative prediction for systems with a mixed phase space is a long-standing open challenge. In such systems regions of regular and chaotic dynamics coexist in phase space, which are classically separated but quantum mechanically coupled by the process of dynamical tunneling. We derive a prediction of dynamical tunneling rates which describe the decay of states localized inside the regular region towards the so-called chaotic sea. This approach uses a fictitious integrable system which mimics the dynamics inside the regular domain and extends it into the chaotic region. Excellent agreement with numerical data is found for kicked systems, billiards, and optical microcavities, if nonlinear resonances are negligible. Semiclassically, however, such nonlinear resonance chains dominate the tunneling process. Hence, we combine our approach with an improved resonance-assisted tunneling theory and derive a unified prediction which is valid from the quantum to the semiclassical regime. We obtain results which show a drastically improved accuracy of several orders of magnitude compared to previous studies. (orig.)

  10. Phase equilibria in the neodymium–cadmium binary system

    Energy Technology Data Exchange (ETDEWEB)

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L.; Ipser, Herbert, E-mail: herbert.ipser@univie.ac.at

    2014-09-01

    Highlights: • The Nd–Cd phase diagram was constructed using a combination of DTA, SEM, XRD and dilatometry data. • Seven intermetallic compounds were confirmed and their phase boundaries were estimated by a combination of all available results. • X-ray diffraction was used to confirm the crystal structure of all intermetallic compounds. • A dilatometric study was performed for Nd–Cd samples up to 4 at.% Cd. - Abstract: The equilibrium phase diagram of the neodymium–cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd{sub 2} (995 °C), Nd{sub 11}Cd{sub 45} (855 °C), and four incongruently melting compounds NdCd{sub 3} (860 °C), Nd{sub 13}Cd{sub 58} (740 °C), NdCd{sub 6} (655 °C) and NdCd{sub 11} (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd–Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

  11. Phase relations in the U-Mo-Al ternary system

    Science.gov (United States)

    Noël, H.; Tougait, O.; Dubois, S.

    2009-06-01

    The phase relations in the U-Mo-Al system of quenched samples annealed at 800 °C for 2 weeks and at 400 °C for 2 months have been established using X-ray powder diffraction, scanning electron microscopy and energy dispersive spectroscopic analysis performed at room temperature. Two ternary Al-rich phases, UMo 2-xAl 20+x and U 6Mo 4+xAl 43-x are found stable at 800 °C and 400 °C. They show significant homogeneity ranges resulting from Mo/Al substitution mechanism on various mixed crystallographic sites, as evidenced by single-crystal structure refinements. Substitution of up to 25 at.% of Al by Mo atoms is also observed for UAl 2 (cubic MgCu 2-type) giving a quite large extension (UAl 2-xMo x, 0 nuclear fuel plates can be successively estimated as composed of the two- and three-phase fields equilibrium indicated on the assessment of the phase relations drawn for samples heat-treated at 400 °C.

  12. Binocular stereo vision system based on phase matching

    Science.gov (United States)

    Liu, Huixian; Huang, Shujun; Gao, Nan; Zhang, Zonghua

    2016-11-01

    Binocular stereo vision is an efficient way for three dimensional (3D) profile measurement and has broad applications. Image acquisition, camera calibration, stereo matching, and 3D reconstruction are four main steps. Among them, stereo matching is the most important step that has a significant impact on the final result. In this paper, a new stereo matching technique is proposed to combine the absolute fringe order and the unwrapped phase of every pixel. Different from traditional phase matching method, sinusoidal fringe in two perpendicular directions are projected. It can be realized through the following three steps. Firstly, colored sinusoidal fringe in both horizontal (red fringe) and vertical (blue fringe) are projected on the object to be measured, and captured by two cameras synchronously. The absolute fringe order and the unwrapped phase of each pixel along the two directions are calculated based on the optimum three-fringe numbers selection method. Then, based on the absolute fringe order of the left and right phase maps, stereo matching method is presented. In this process, the same absolute fringe orders in both horizontal and vertical directions are searched to find the corresponding point. Based on this technique, as many as possible pairs of homologous points between two cameras are found to improve the precision of the measurement result. Finally, a 3D measuring system is set up and the 3D reconstruction results are shown. The experimental results show that the proposed method can meet the requirements of high precision for industrial measurements.

  13. Phase equilibria in the Ni-Fe-Ga alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Ducher, R. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579 (Japan); Kainuma, R. [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Sendai 980-8577 (Japan)], E-mail: kainuma@tagen.tohoku.ac.jp; Ishida, K. [Department of Materials Science, Graduate School of Engineering, Tohoku University, 6-6-02 Aoba-yama, Sendai 980-8579 (Japan)

    2008-09-08

    The phase equilibria, A2/B2 and B2/L2{sub 1} (or D0{sub 3}) order-disorder transitions and martensitic transformation on the Ni-Fe side of the Ni-Fe-Ga system were examined by electron probe microanalysis (EPMA) and differential scanning calorimetric (DSC) measurement. The equilibrium compositions of interrelations mainly among the {alpha} (A2), {beta} (B2), {beta}' (L2{sub 1} or D0{sub 3}), {gamma} (A1) and {gamma}' (L1{sub 2}) phases were determined using diffusion triples which were fabricated by two-step diffusion coupling. It was confirmed that a bcc single-phase region composed of {alpha}, {beta} and {beta}' at 850-1000 deg. C exists in a wide composition range and that the critical temperature of the B2/L2{sub 1} order-disorder transformation in the Fe{sub 3}Ga-Ni{sub 3}Ga pseudo-binary section gradually increases with increasing Ni content. The existing composition region of the martensite phase at room temperature was also determined by the diffusion triple method.

  14. Enhancing the performance of BICPV systems using phase change materials

    Science.gov (United States)

    Sharma, Shivangi; Sellami, Nazmi; Tahir, Asif; Reddy, K. S.; Mallick, Tapas K.

    2015-09-01

    Building Integrated Concentrated Photovoltaic (BICPV) systems have three main benefits for integration into built environments, namely, (i) generating electricity at the point of use (ii) allowing light efficacy within the building envelope and (iii) providing thermal management. In this work, to maintain solar cell operating temperature and improve its performance, a phase change material (PCM) container has been designed, developed and integrated with the BICPV system. Using highly collimated continuous light source, an indoor experiment was performed. The absolute electrical power conversion efficiency for the module without PCM cooling resulted in 7.82% while using PCM increased it to 9.07%, thus showing a relative increase by 15.9% as compared to a non- PCM system. A maximum temperature reduction of 5.2°C was also observed when the BICPV module was integrated with PCM containment as compared to the BICPV system without any PCM containment.

  15. Phase Transitions and Metastability in Self-Propelled Particle systems

    Science.gov (United States)

    Kulkarni, Ajinkya; Thampi, Sumesh; Panchagnula, Mahesh

    2016-11-01

    Ordered motion of self-propelling micro-organisms produce interesting patterns. The objective of this study is to investigate the nature of the transition from disorganized thermal-like motion to organized vortical motion, and the resulting metastability in systems of self-propelled particles. A modified version of the Standard Vicsek Model has been used, where the particles are modeled as soft disks with finite mass, confined in a circular domain. We observe multiple phases as the local co-ordination coefficient is varied. We analyze the nature of transitions by calculating Binder Cumulants of the order parameters. An occurrence of metastability is investigated in the hysteretic region. The switching between the steady states of the system in the hysteretic region has been triggered via artificial nucleation of randomly picked particles spanning the entire domain. In addition, the effect of domain size on the nature of the phase transitions has been studied. Finally the motivation for these phase transitions has been explained via thrust generation ability and the geometry of the confinement.

  16. Uhlmann Connection in Fermionic Systems Undergoing Phase Transitions

    Science.gov (United States)

    Mera, Bruno; Vlachou, Chrysoula; Paunković, Nikola; Vieira, Vítor R.

    2017-07-01

    We study the behavior of the Uhlmann connection in systems of fermions undergoing phase transitions. In particular, we analyze some of the paradigmatic cases of topological insulators and superconductors in one dimension, as well as the BCS theory of superconductivity in three dimensions. We show that the Uhlmann connection signals phase transitions in which the eigenbasis of the state of the system changes. Moreover, using the established fidelity approach and the study of the edge states, we show the absence of thermally driven phase transitions in the case of topological insulators and superconductors. We clarify what is the relevant parameter space associated with the Uhlmann connection so that it signals the existence of order in mixed states. In addition, the study of Majorana modes at finite temperature opens the possibility of applications in realistic stable quantum memories. Finally, the analysis of the different behavior of the BCS model and the Kitaev chain, with respect to the Uhlmann connection, suggested that in realistic scenarios the gap of topological superconductors could also, generically, be temperature dependent.

  17. PHASE II VAULT TESTING OF THE ARGONNE RFID SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Willoner, T.; Turlington, R.; Koenig, R.

    2012-06-25

    The U.S. Department of Energy (DOE) (Environmental Management [EM], Office of Packaging and Transportation [EM-45]) Packaging and Certification Program (DOE PCP) has developed a Radio Frequency Identification (RFID) tracking and monitoring system, called ARG-US, for the management of nuclear materials packages during transportation and storage. The performance of the ARG-US RFID equipment and system has been fully tested in two demonstration projects in April 2008 and August 2009. With the strong support of DOE-SR and DOE PCP, a field testing program was completed in Savannah River Site's K-Area Material Storage (KAMS) Facility, an active Category I Plutonium Storage Facility, in 2010. As the next step (Phase II) of continued vault testing for the ARG-US system, the Savannah River Site K Area Material Storage facility has placed the ARG-US RFIDs into the 910B storage vault for operational testing. This latest version (Mark III) of the Argonne RFID system now has the capability to measure radiation dose and dose rate. This paper will report field testing progress of the ARG-US RFID equipment in KAMS, the operability and reliability trend results associated with the applications of the system, and discuss the potential benefits in enhancing safety, security and materials accountability. The purpose of this Phase II K Area test is to verify the accuracy of the radiation monitoring and proper functionality of the ARG-US RFID equipment and system under a realistic environment in the KAMS facility. Deploying the ARG-US RFID system leads to a reduced need for manned surveillance and increased inventory periods by providing real-time access to status and event history traceability, including environmental condition monitoring and radiation monitoring. The successful completion of the testing program will provide field data to support a future development and testing. This will increase Operation efficiency and cost effectiveness for vault operation. As the next step

  18. Smart co-phasing system for segmented mirror telescopes

    Science.gov (United States)

    Simar, Juan F.; Stockman, Yvan; Surdej, Jean

    2016-07-01

    Space observations of fainter and more distant astronomical objects constantly require telescope primary mirrors with a larger size. The diameter of monolithic primary mirrors is limited to 10 m because of manufacturing and logistics limitations. For space telescopes, monolithic primary mirrors are limited to less than 5 m due to fairing capacity. Segmented primary mirrors thus constitute an alternative solution to deal with the steadily increase of the primary mirror size. The optical path difference between the individual segments must be close to zero (few nm) in order to be diffraction limited over the full telescope aperture. In this paper a new system that may co-phase 7 segments at once with the light of a star and without artificial one is proposed. First the measuring methods and feedback system is explained, then the breadboard setup is presented and the results are analyzed and discussed, finally a comparison with Keck telescope is performed. This system can be adapted in order to be used in the co-phasing system of future segmented mirrors, its dynamic range starts from several hundred of microns till some tenths of nanometers

  19. Comprehensive research on self phase modulation based optical delay systems

    Institute of Scientific and Technical Information of China (English)

    Yang Ai-Ying; Sun Yu-Nan

    2010-01-01

    This paper comprehensively investigates the properties of self phase modulation based optical delay systems consisting of dispersion compensation fibre and highly nonlinear fibres.It researches into the impacts of power level launched into highly nonlinear fibres,conversion wavelength,dispersion slope,modulation format and optical filter bandwidth on the overall performance of optical delay systems.The results reveal that,if the power launched into highly nonlinear fibres is fixed,the time delay generally varies linearly with the conversion wavelength,but jumps intermittently at some conversion wavelengths.However,the time delay varies semi-periodically with the power launched into highly nonlinear fibres.The dispersion slope of highly nonlinear fibres has significant influence on the time delay,especially for the negative dispersion slope.The time delay differs with modulation formats due to the different combined interaction of nonlinearity and dispersion in fibres.The bandwidth of the optical filters also greatly affects the time delay because it determines the bandwidth of the passed signal in the self phase modulation based time delay systems.The output signal quality of the overall time delay systems depends on the conversion wavelength and input power level.The optimisation of the power level and conversion wavelength to provide the best output signal quality is made at the end of this paper.

  20. Phase relations in the forsterite-diopside-jadeite system.

    Science.gov (United States)

    Butvina, V.; Litvin, Yu.

    2009-04-01

    this problem. Due to this fact the main purpose of this paper is an experimental study of phase relationships in the model system forsterite-dioside-jadeite at pressure of 7 GPa and foundation of possible physico-chemical correct transitions between peridotite and eclogite parageneses with overcoming liquidus "eclogite" thermal barrier. To construct a diagram of a ternary system forsterite-diopside-jadeite it is necessary to study its boundary binary sections forsterite-jadeite and fosterite-diopside as well as a number of internal polythermic sections. The section jadeite-diopside at 7 GPa has been studied earlier (Bobrov, Litvin, Kojitani, Akaogi, 2006; 2008) and it is characterized by the unlimited miscibility of jadeite and diopside components in solid and liquid states. The first experimental results obtained at the initial stage of the investigation of this problem can be characterized as follows. Forsterite-jadeite section. The experiments in this section have been done in the temperature range of 1100-18000C on which basis the construction of fusibility diagram of the system forsterite-jadeite at 7 GPa has been started. The obtained experimental data testify to the existence in the system of the liquidus fields Fo + L, GrtSS + L and CpxSS (on the basis of jadeite phase) +L, as well as show indirectly a possible appearance of orthopyroxene as a liquidus phase. In subsolidus experiments olivine-bearing assemblages on the basis of the paragenesis Ol+Grt+Opx+Cpx are found. Garnet there is not a pure pyrope, but has the molecule Na2MgSi5O12 (Na-majorite) what manifests itself in the direct correlation of Na and Si in the equations of this phase. OpxSS is not a pure enstatite, but forms a complicated solid solution En+Jd+Mg-Ts. With jadeite content increase in the system olivine-bearing assemblages transfer into non-olivine ones, up to the assemblage Cpx + Grt (jadeite-clinopyroxene has also enstatite component) being indirect evidence of a peritectic character of

  1. A two-phase system call arguments attribute analyzing method

    Institute of Scientific and Technical Information of China (English)

    LI Hong-jiao; LI Jian-hua

    2008-01-01

    To detect more attacks aiming at key security data in program behavior-based anomaly detection, the data flow properties were formulated as unary and binary relations on system call arguments. A new method named two-phrase analysis (2PA) is designed to analyze the efficient relation dependency, and its description as well as advantages are discussed. During the phase of static analysis, a dependency graph was constructed according to the program's data dependency graph, which was used in the phase of dynamic learning to learn specified binary relations. The constructed dependency graph only stores the information of related arguments and events, thus improves the efficiency of the learning algorithm and reduces the size of learned relation de-pendencies. Performance evaluations show that the new method is more efficient than existing methods.

  2. Large resistivity modulation in mixed-phase metallic systems

    Science.gov (United States)

    Lee, Yeonbae; Liu, Zhiqi; Heron, John; Clarkson, James; Hong, Jeongmin; Ko, Changhyun; Biegalski, Michael; Aschauer, Ulrich; Hsu, Shang-Lin; Nowakowski, Mark; Wu, Junqiao; Christen, Hans; Salahuddin, Sayeef; Bokor, Jeffrey; Spaldin, Nicola; Schlom, Darrell; Ramesh, Ramamoorthy

    2015-03-01

    We have investigated the effect of an electric field to FeRh/PMN-PT heterostructures and report 8% change in the electrical resistivity of FeRh films. Such a ``giant'' electroresistance (GER) response is striking in metallic systems, in which external electric fields are screened and thus only weakly influence the carrier concentrations and mobilities. We show that our FeRh films comprise coexisting ferromagnetic and antiferromagnetic phases with different resistivities, and the origin of the GER effect is the strain-mediated change in their relative proportions. The observed behavior is reminiscent of colossal magnetoresistance in perovskite manganites, and illustrates the role of mixed-phase coexistence in achieving large changes in physical properties with low-energy external perturbation.

  3. Identifying phase synchronization clusters in spatially extended dynamical systems

    CERN Document Server

    Bialonski, Stephan; 10.1103/PhysRevE.74.051909

    2010-01-01

    We investigate two recently proposed multivariate time series analysis techniques that aim at detecting phase synchronization clusters in spatially extended, nonstationary systems with regard to field applications. The starting point of both techniques is a matrix whose entries are the mean phase coherence values measured between pairs of time series. The first method is a mean field approach which allows to define the strength of participation of a subsystem in a single synchronization cluster. The second method is based on an eigenvalue decomposition from which a participation index is derived that characterizes the degree of involvement of a subsystem within multiple synchronization clusters. Simulating multiple clusters within a lattice of coupled Lorenz oscillators we explore the limitations and pitfalls of both methods and demonstrate (a) that the mean field approach is relatively robust even in configurations where the single cluster assumption is not entirely fulfilled, and (b) that the eigenvalue dec...

  4. Urban Integrated Industrial Cogeneration Systems Analysis. Phase II final report

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Through the Urban Integrated Industrial Cogeneration Systems Analysis (UIICSA), the City of Chicago embarked upon an ambitious effort to identify the measure the overall industrial cogeneration market in the city and to evaluate in detail the most promising market opportunities. This report discusses the background of the work completed during Phase II of the UIICSA and presents the results of economic feasibility studies conducted for three potential cogeneration sites in Chicago. Phase II focused on the feasibility of cogeneration at the three most promising sites: the Stockyards and Calumet industrial areas, and the Ford City commercial/industrial complex. Each feasibility case study considered the energy load requirements of the existing facilities at the site and the potential for attracting and serving new growth in the area. Alternative fuels and technologies, and ownership and financing options were also incorporated into the case studies. Finally, site specific considerations such as development incentives, zoning and building code restrictions and environmental requirements were investigated.

  5. First-Principles Phase Diagram for Ce-Th System

    Energy Technology Data Exchange (ETDEWEB)

    Landa, A; Soderlind, P; Ruban, A; Vitos, L; Pourovskii, L

    2004-05-11

    Ab initio total energy calculations based on the exact muffin-tin orbitals (EMTO) theory are used to determine the high pressure and low temperature phase diagram of Ce and Th metals as well as the Ce{sub 43}Th{sub 57} disordered alloy. The compositional disorder for the alloy is treated in the framework of the coherent potential approximation (CPA). Equation of state for Ce, Th and Ce{sub 43}Th{sub 57} has been calculated up to 1 Mbar in good comparison with experimental data: upon compression the Ce-Th system undergoes crystallographic phase transformation from an fcc to a bct structure and the transition pressure increases with Th content in the alloy.

  6. P T phase transition in multidimensional quantum systems

    Science.gov (United States)

    Bender, Carl M.; Weir, David J.

    2012-10-01

    Non-Hermitian P T-symmetric quantum-mechanical Hamiltonians generally exhibit a phase transition that separates two parametric regions, (i) a region of unbroken P T symmetry in which the eigenvalues are all real, and (ii) a region of broken P T symmetry in which some of the eigenvalues are complex. This transition has recently been observed experimentally in a variety of physical systems. Until now, theoretical studies of the P T phase transition have generally been limited to one-dimensional models. Here, four nontrivial coupled P T-symmetric Hamiltonians, H=\\textstyle {\\frac{1}{2}}p^2+\\textstyle {\\frac{1}{2}}x^2+\\textstyle {\\frac{1}{2}}q^2+\\textstyle {\\frac{1}{2}}y^2+igx^2y, H=\\textstyle {\\frac{1}{2}}p^2+\\textstyle {\\frac{1}{2}}x^2+\\textstyle {\\frac{1}{2}}q^2+y^2+igx^2y, H=\\textstyle {\\frac{1}{2}}p^2+\\textstyle {\\frac{1}{2}}x^2+\\textstyle {\\frac{1}{2}}q^2+\\textstyle {\\frac{1}{2}}y^2+\\textstyle {\\frac{1}{2}}r^2+\\textstyle {\\frac{1}{2}}z^2+igxyz, and H=\\textstyle {\\frac{1}{2}}p^2+ \\textstyle {\\frac{1}{2}}x^2+\\textstyle {\\frac{1}{2}}q^2+y^2+\\textstyle {\\frac{1}{2}}r^2+\\textstyle {\\frac{3}{2}}z^2+igxyz are examined. Based on extensive numerical studies, this paper conjectures that all four models exhibit a phase transition. The transitions are found to occur at g ≈ 0.1, g ≈ 0.04, g ≈ 0.1 and g ≈ 0.05. These results suggest that the P T phase transition is a robust phenomenon not limited to systems having one degree of freedom.

  7. Harmonics Phase Shifter for a Three-Phase System with Voltage Control by Integral-Cycle Triggering Mode of Thyristors

    Directory of Open Access Journals (Sweden)

    I. Badran

    2008-01-01

    Full Text Available n integral-cycle triggering mode of voltage control, subharmonic as well as higher order harmonic components are generated in the load voltage waveforms of a three-phase system. These harmonic components are found to be unbalanced in phase displacement. The correction of the unbalanced phase displacement angles of a particular subharmonic or higher order harmonic for this type of triggering is investigated to solve the limitation of use of this important type of control as a drive and many other industrial applications. In this research a new phase shifting technique is proposed to correct the unbalanced phase displacement angles in the three-phase system. This technique depends on shifting the waveforms of either phase B or phase C or both by multiples of 2π. A microprocessor-based harmonic phase shifter is designed and tested with three-phase resistive and induction motor loads. It is found that there is a well agreement between the theoretical and experimental results and it is believed that the major problem of harmonics phase unbalances associated with the integral-cycle triggering mode of thyristors when used with three-phase circuits have been solved in the present research.

  8. Phase diagram of power law and Lennard-Jones systems: Crystal phases

    Energy Technology Data Exchange (ETDEWEB)

    Travesset, Alex [Ames Laboratory

    2014-10-28

    An extensive characterization of the low temperature phase diagram of particles interacting with power law or Lennard-Jones potentials is provided from Lattice Dynamical Theory. For power law systems, only two lattice structures are stable for certain values of the exponent (or softness) (A15, body centered cube (bcc)) and two more (face centered cubic (fcc), hexagonal close packed (hcp)) are always stable. Among them, only the fcc and bcc are equilibrium states. For Lennard-Jones systems, the equilibrium states are either hcp or fcc, with a coexistence curve in pressure and temperature that shows reentrant behavior. The hcp solid never coexists with the liquid. In all cases analyzed, for both power law and Lennard-Jones potentials, the fcc crystal has higher entropy than the hcp. The role of anharmonic terms is thoroughly analyzed and a general thermodynamic integration to account for them is proposed.

  9. Random phase wave: a soluble non-Markovian system

    Energy Technology Data Exchange (ETDEWEB)

    Dewar, R.L.

    1977-12-01

    The averaged propagator and the corresponding mass operator (non-Markovian particle-wave collision operator) of a particle being accelerated by a random potential are constructed explicitly in a model system. The model consists of an ensemble of monochromatic waves of random phase, such as arises in narrow-bandwidth plasma turbulence, and is particularly interesting as a system exhibiting strong trapping. An essential simplifying feature is that the propagator is evaluated in oscillation-center picture, which greatly simplifies the momentum-space operators occurring in the problem, and leads to a remarkable factorization of the mass operator. General analyticity and symmetry properties are derived using a projection-operator method, and verified for the solution of the model system. The nature of the memory exhibited by the mass operator is briefly examined.

  10. A Systematic Modelling Framework for Phase Transfer Catalyst Systems

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Sales-Cruz, Mauricio; Hyung Kim, Sun

    2016-01-01

    in an aqueous phase. These reacting systems are receiving increased attention as novel organic synthesis options due to their flexible operation, higher product yields, and ability to avoid hazardous or expensive solvents. Major considerations in the design and analysis of PTC systems are physical and chemical...... equilibria, as well as kinetic mechanisms and rates. This paper presents a modelling framework for design and analysis of PTC systems that requires a minimum amount of experimental data to develop and employ the necessary thermodynamic and reaction models and embeds them into a reactor model for simulation....... The application of the framework is made to two cases in order to highlight the performance and issues of activity coefficient models for predicting design and operation and the effects when different organic solvents are employed....

  11. Phase transition in PT symmetric active plasmonic systems

    CERN Document Server

    Mattheakis, M; Molina, M I; Tsironis, G P

    2015-01-01

    Surface plasmon polaritons (SPPs) are coherent electromagnetic surface waves trapped on an insulator-conductor interface. The SPPs decay exponentially along the propagation due to conductor losses, restricting the SPPs propagation length to few microns. Gain materials can be used to counterbalance the aforementioned losses. We provide an exact expression for the gain, in terms of the optical properties of the interface, for which the losses are eliminated. In addition, we show that systems characterized by lossless SPP propagation are related to PT symmetric systems. Furthermore, we derive an analytical critical value of the gain describing a phase transition between lossless and prohibited SPPs propagation. The regime of the aforementioned propagation can be directed by the optical properties of the system under scrutiny. Finally, we perform COMSOL simulations verifying the theoretical findings.

  12. Phase-coupled optical diode based on PT symmetric system

    Science.gov (United States)

    Gao, Yong-Pan; Cao, Cong; Zhang, Yong; Wang, Tie-Jun; Wang, Chuan

    2017-01-01

    Here we investigate a phase-coupled parity-time symmetric plasmonic system, and theoretically achieved the all optical on-chip plasmonic diode using the coupled mode theory. The proposed symmetrical system consists of one loss cavity and one gain cavity each coupled with the waveguide, and we find that the controllable amplification of the input field can be achieved by changing the power coupling fraction between the resonators and the waveguide. Moreover, this loss-gain symmetric system could work as a frequency comb filter, and the operation on the device could be controlled by tuning the coupling strength between the two plasmonic cavities by tuning the coupling distance between the cavities and the waveguide.

  13. Phase Transitions and Scaling in Systems Far from Equilibrium

    Science.gov (United States)

    Täuber, Uwe C.

    2017-03-01

    Scaling ideas and renormalization group approaches proved crucial for a deep understanding and classification of critical phenomena in thermal equilibrium. Over the past decades, these powerful conceptual and mathematical tools were extended to continuous phase transitions separating distinct nonequilibrium stationary states in driven classical and quantum systems. In concordance with detailed numerical simulations and laboratory experiments, several prominent dynamical universality classes have emerged that govern large-scale, long-time scaling properties both near and far from thermal equilibrium. These pertain to genuine specific critical points as well as entire parameter space regions for steady states that display generic scale invariance. The exploration of nonstationary relaxation properties and associated physical aging scaling constitutes a complementary potent means to characterize cooperative dynamics in complex out-of-equilibrium systems. This review describes dynamic scaling features through paradigmatic examples that include near-equilibrium critical dynamics, driven lattice gases and growing interfaces, correlation-dominated reaction-diffusion systems, and basic epidemic models.

  14. The Cu-Bi-Se phase system at temperatures between 300° and 750° C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven

    2003-01-01

    Phase relations were determined in the Cu-Bi-Se phase system at 300, 350, 400, 450, 550, 650 and 750degreesC. Four ternary phases, phase A-D, have been synthesized. Phase A (Cu4Bi4Se9) is isotype with Cu4Bi4S9, and phase B (Cu1.7Bi4.7 Se-8) and phase C (Cu3Bi5Se9) have the same structure type as P...

  15. Phase equilibria in the neodymium-cadmium binary system.

    Science.gov (United States)

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L; Ipser, Herbert

    2014-09-05

    The equilibrium phase diagram of the neodymium-cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd-Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd.

  16. Phase equilibria in the neodymium–cadmium binary system

    Science.gov (United States)

    Skołyszewska-Kühberger, Barbara; Reichmann, Thomas L.; Ipser, Herbert

    2014-01-01

    The equilibrium phase diagram of the neodymium–cadmium system has been established by thermal, metallographic and X-ray analysis based on a study of 70 alloys. The system contains three congruently melting intermetallic compounds, i.e. NdCd (1040 °C), NdCd2 (995 °C), Nd11Cd45 (855 °C), and four incongruently melting compounds NdCd3 (860 °C), Nd13Cd58 (740 °C), NdCd6 (655 °C) and NdCd11 (520 °C). Four eutectic reactions are found in this binary system, i.e. at ∼25 at.% Cd and 770 °C, at 58 at.% Cd and 955 °C, at 79 at.% Cd and 850 °C, and very close to pure Cd at 318 °C, as well as one eutectoid reaction at ∼15 at.% Cd and 500 °C. The solid solubility of Nd in Cd is negligible. Dilatometric curves were recorded for three Nd–Cd compositions up to 4 at.% Cd, to accurately determine phase transitions between the solid solutions of Cd in the low- and high-temperature modification of Nd. PMID:25197164

  17. Spectral Weighting Functions for Single-symbol Phase-noise Specifications in OFDM Systems

    NARCIS (Netherlands)

    Hoeksema, Fokke; Schiphorst, Roel; Slump, Kees

    2003-01-01

    For the specification of phase-noise requirements for the front-end of a HiperLAN/2 system we investigated available literature on the subject. Literature differed in several aspects. One aspect is in the type of phase-noise used (Wiener phase-noise or small-angle phase noise). A Wiener phase-noise

  18. Quantum phase transitions about parity breaking in matrix product systems

    Institute of Scientific and Technical Information of China (English)

    ZHU Jing-Min

    2011-01-01

    According to our scheme to construct quantum phase transitions (QPTs) in spin chain systems with matrix product ground states, we first successfully combine matrix product state (MPS) QPTs with spontaneous symmetry breaking. For a concrete model, we take into account a kind of MPS QPTs accompanied by spontaneous parity breaking, though for either side of the critical point the GS is typically unique, and show that the kind of MPS QPTs occur only in the thermodynamic limit and are accompanied by the appearance of singularities, diverging correlation length, vanishing energy gap and the entanglement entropy of a half-infinite chain not only staying finite but also whose first derivative discontinuous.

  19. Blind Deconvolution in Nonminimum Phase Systems Using Cascade Structure

    Directory of Open Access Journals (Sweden)

    Liqing Zhang

    2007-01-01

    Full Text Available We introduce a novel cascade demixing structure for multichannel blind deconvolution in nonminimum phase systems. To simplify the learning process, we decompose the demixing model into a causal finite impulse response (FIR filter and an anticausal scalar FIR filter. A permutable cascade structure is constructed by two subfilters. After discussing geometrical structure of FIR filter manifold, we develop the natural gradient algorithms for both FIR subfilters. Furthermore, we derive the stability conditions of algorithms using the permutable characteristic of the cascade structure. Finally, computer simulations are provided to show good learning performance of the proposed method.

  20. Simulation of a Marine Controllable Phase-Compounding Excitation System

    Institute of Scientific and Technical Information of China (English)

    GAO Hai-bo; WU Fu-yuan; CHEN Hui

    2007-01-01

    We first established the mathematical model of a marine synchronous generator and its controllable phase-compounding excitation system, and then made a simulation sketch with Saber simulation software. According to "Regulations for the Construction and Classification of Ocean-going Steel Ships" of the China Classification Society (CCS) , some experiments are designed to verify the property of the simulation model. Some experiments, such as free start, load sudden on and off, have been completed, and the result indicates that the model conforms to the requirements of the rules very well. It is qualified for a marine electrical propulsion simulation.

  1. Dual view on sliding phases in U (1 ) symmetric systems

    Science.gov (United States)

    Vayl, S.; Kuklov, A. B.; Oganesyan, V.

    2017-03-01

    The proposal of sliding phases (SP) is revisited from the perspective of duality. A generic argument is formulated as essentially a no-go theorem for SP in translationally invariant nonfrustrated systems with short-range interactions—classical or quantum. Its validity is demonstrated on an asymmetric bilayer and its multilayer variation models where the duality allows obtaining asymptotically exact analytical solution. This solution is in drastic contrast with the perturbative renormalization group prediction and is strongly supported by Monte Carlo simulations. An alternative path toward finding SP is suggested. Its key ingredient is a long-range gauge-type interaction suppressing the interlayer Josephson coupling.

  2. Optical signal monitoring in phase modulated optical fiber transmission systems

    Science.gov (United States)

    Zhao, Jian

    Optical performance monitoring (OPM) is one of the essential functions for future high speed optical networks. Among the parameters to be monitored, chromatic dispersion (CD) is especially important since it has a significant impact on overall system performance. In this thesis effective CD monitoring approaches for phase-shift keying (PSK) based optical transmission systems are investigated. A number of monitoring schemes based on radio frequency (RF) spectrum analysis and delay-tap sampling are proposed and their performance evaluated. A method for dispersion monitoring of differential phase-shift keying (DPSK) signals based on RF power detection is studied. The RF power spectrum is found to increase with the increase of CD and decrease with polarization mode dispersion (PMD). The spectral power density dependence on CD is studied theoretically and then verified through simulations and experiments. The monitoring sensitivity for nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) and return-to-zero differential phase-shift keying (RZ-DPSK) based systems can reach 80ps/nm/dB and 34ps/nm/dB respectively. The scheme enables the monitoring of differential group delay (DGD) and CD simultaneously. The monitoring sensitivity of CD and DGD can reach 56.7ps/nm/dB and 3.1ps/dB using a bandpass filter. The effects of optical signal-to-noise ratio (OSNR), DGD, fiber nonlinearity and chirp on the monitoring results are investigated. Two RF pilot tones are employed for CD monitoring of DPSK signals. Specially selected pilot tone frequencies enable good monitoring sensitivity with minimum influence on the received signals. The dynamic range exceeding 35dB and monitoring sensitivity up to 9.5ps/nm/dB are achieved. Asynchronous sampling technique is employed for CD monitoring. A signed CD monitoring method for 10Gb/s NRZ-DPSK and RZ-DPSK systems using asynchronous delay-tap sampling technique is studied. The demodulated signals suffer asymmetric waveform distortion if

  3. Feedback diagonal canonical form and its application to stabilization of nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    CHENG Daizhan; HU Qingxi; QIN Huashu

    2005-01-01

    This paper considers the problem of stabilization of a class of nonlinear systems, which are possibly of non-minimum phase. A new feedback-equivalent canonical form, called diagonal normal form, of linear control systems is proposed. Using it, the corresponding normal form of affine nonlinear control systems is obtained. Based on this new normal form and the design technique of center manifold, a new constructing method for stabilizing control is presented. Certain examples are included to demonstrate the design strategy of stabilizers.

  4. Towards a robust phase locked loop tune feedback system

    CERN Document Server

    Jones, R; Luo, Y

    2005-01-01

    Attempts to introduce a reliable tune feedback loop at RHIC (BNL) [1] have been thwarted by two main problems, namely transition crossing and betatron coupling. The problem of transition crossing is a dynamic range problem, resulting from the increase in the revolution content of the observed signal as the bunch length becomes short and from the fast orbit changes that occur during transition. The dynamic range issue is being addressed by the development of a baseband tune measurement system [2] as part of the US LHC Accelerator Research Program (US-LARP). This paper will focus on the second problem, showing how a phase locked loop (PLL) tune measurement system can be used to continuously measure global betatron coupling, and in so doing allow for robust tune measurement and feedback in the presence of coupling.

  5. Phase transitions, scaling and renormalisation in nonequilibrium systems

    CERN Document Server

    Hanney, T E

    2002-01-01

    critical fixed point. Extensions to include disorder, to higher dimensions, and to other models are all possible using the method. Using the mapping between the Master equation and the Schroedinger equation in imaginary time, this scaling procedure is rephrased as a new blocking for quantum-spin systems. Existing methods of real space renormalisation for quantum-spin systems are applied to a variety of previously unconsidered exclusion models. In particular, it is shown how such techniques can be applied to models whose dynamics conserve particle number. Finally, by applying a Trotter decomposition to the quantum-spin Hamiltonian, it is shown how a nonequilibrium exclusion model can be written in terms of a classical Hamiltonian for Ising spin variables in one higher dimension. This mapping admits the possibility rescaling time and length scales separately, and with reference to a specific update mechanism. Nonequilibrium phase transitions and critical phenomena in simple lattice-based interacting particle mo...

  6. Classical and quantum phases of low-dimensional dipolar systems

    Energy Technology Data Exchange (ETDEWEB)

    Cartarius, Florian

    2016-09-22

    In this thesis we present a detailed study of the phase diagram of ultracold bosonic atoms confined along a tight atomic wave guide, along which they experience an optical lattice potential. In this quasi-one dimensional model we analyse the interplay between interactions and quantum fluctuations in (i) determining the non-equilibrium steady state after a quench and (ii) giving rise to novel equilibrium phases, when the interactions combine the s-wave contact interaction and the anisotropic long range dipole-dipole interactions. In detail, in the first part of the thesis we study the depinning of a gas of impenetrable bosons following the sudden switch of of the optical lattice. By means of a Bose-Fermi mapping we infer the exact quantum dynamical evolution and show that in the thermodynamic limit the system is in a non-equilibrium steady state without quasi-long range order. In the second part of the thesis, we study the effect of quantum fluctuations on the linear-zigzag instability in the ground state of ultracold dipolar bosons, as a function of the strength of the transverse confinement. We first analyse the linear-zigzag instability in the classical regime, and then use our results to develop a multi-mode Bose-Hubbard model for the system. We then develop several numerical methods, to determine the ground state.

  7. Pilot System for the Phase 1 Pixel Upgrade

    CERN Document Server

    AUTHOR|(CDS)2072269

    2015-01-01

    The CMS phase 1 pixel upgrade is planned for installation in 2016-2017, incorporating new front-end ASICs with digital 400 Mbps data links to handle a higher instantaneous luminosity of up to 2.5 $x$ 10$^{34}$ cm$^{-2}$ s$^{-1}$ and trigger rates of 100 kHz with bunch spacing scenarios of 25 or 50 ns. The new digital readout requires new back-end electronics incorporating faster optical receivers and firmware for decoding the new data format. Additionally the phase 1 upgrade is powered from DC-DC converters installed inside CMS close to the modules. To gain experience with this new readout chain and DC-DC converters under realistic operating conditions (trigger rates, backgrounds, high data occupancy, and possible single-event upsets) a pilot detector system comprising eight sensor modules, service electronics, optical links, and back-end electronics has been prepared using pre-production parts. The pilot system was installed with the present forward pixel detector in 2014 during long shutdown 1 (LS1). The pi...

  8. Digital Phased Array Ultrasonic Inspection system with dynamic focusing

    Science.gov (United States)

    Hwang, J. S.; Shin, H. J.; Song, S. J.; Song, T. K.

    2000-05-01

    Enhancement of the ultrasonic flaw detection and characterization is expected through the development of a high performance PAULI (Phased Array Ultrasonic Inspection) system which can provide high resolution two-dimensional (sector scan: S-scan) images. The high-resolution S-scan image renders inspection results more readable compared to the conventional A-scan and B-scan results. Therefore, it can improve inspection efficiency and reliability. In this study, the ultrasonic imaging technologies developed in medical applications were adapted to develop a digital PAULI system for nondestructive testing. To provide real-time S-scan images, the PAULI system uses 64 independent transceiver channels controlled by proper delay laws for steering and focusing the ultrasound beams along each scan lines. The PAULI system employs a novel dynamic receive focusing technique in order to optimize the lateral resolution by focusing the ultrasound wave at all imaging points. The dynamic receive focusing is achieved in real-time by digital signal processing methods. The feasibility of PAULI system is demonstrated for the NDE of steel structures.

  9. Development of Phase Lock Loop System for Synchronisation of a Hybrid System with the Grid

    Directory of Open Access Journals (Sweden)

    A. S. Abubakar

    2016-06-01

    Full Text Available Phase locked loop (PLL is an important part of the control unit of the grid connected power converter. The method of zero crossing detection (ZCD does not produce accurate phase information when grid is non-ideal. In this work, a synchronous reference frame (SRF PLL method to obtain accurate phase information when the grid voltages are unbalanced is proposed. The performances of the PLL have been verified for ideal and abnormal grid conditions such as unbalance, voltage sag, faults condition etc. Based on the results obtained, the developed PLL gives better fault ride when unbalances in the three phase input signals are overall handled well by the PLL system as it locks the two signal back within the first cycle. It also overcomes a phase jump after 5 milli-seconds from the time the fault was introduced and performs better tracking of the grid voltage and that of the renewable energy source.

  10. Development of Phase Lock Loop System for Synchronisation of a Hybrid System with the Grid

    Directory of Open Access Journals (Sweden)

    A. S. Abubakar

    2016-12-01

    Full Text Available Phase locked loop (PLL is an important part of the control unit of the grid connected power converter. The method of zero crossing detection (ZCD does not produce accurate phase information when grid is non-ideal. In this work, a synchronous reference frame (SRF PLL method to obtain accurate phase information when the grid voltages are unbalanced is proposed. The performances of the PLL have been verified for ideal and abnormal grid conditions such as unbalance, voltage sag, faults condition etc. Based on the results obtained, the developed PLL gives better fault ride when unbalances in the three phase input signals are overall handled well by the PLL system as it locks the two signal back within the first cycle. It also overcomes a phase jump after 5 milli-seconds from the time the fault was introduced and performs better tracking of the grid voltage and that of the renewable energy source.

  11. Phases of health promotion implementation into the Scottish school system.

    Science.gov (United States)

    Gugglberger, Lisa; Inchley, Jo

    2014-06-01

    Schools have been identified as ideal settings for health promotion (HP) among children, adolescents and school staff. Most European countries have established strategies to implement HP into their school system, however, little is known about these national strategies and how effective they have been. School HP implementation concerns processes of adoption, adaptation and operation of a complex intervention into a complex setting. This study analyses the processes that have led to school HP implementation in Scotland from the 1980s until now to identify key factors which facilitated and supported effective implementation. In the tradition of case-study research, 14 interviews with representatives of national and local organizations involved in school health, as well as with school staff were conducted. Furthermore, policy documents, reports and guidelines were collected. The data were analysed following a Grounded Theory approach. Four phases of school HP implementation into the Scottish school system were identified: (i) getting started (1980s-1998), (ii) political will and strategic vision (1999-2001), (iii) national leadership (2002-2008), and (iv) integration and embedding into education system (2008-ongoing). Throughout the phases political will and committed actors, the strategy/tradition to give power to the local authorities and individual schools, and the establishment of partnerships and ownership have supported implementation. Scotland is an interesting case giving important insights into the ways and possibilities of negotiating an interdisciplinary and cross-sectoral theme such as HP in schools. Further research concerning different political systems and national implementation processes is important to widen the understanding of national implementation strategies of school HP.

  12. Phase Transitions in Frustrated Vector Spin Systems: Numerical Studies

    Science.gov (United States)

    Loison, Damien

    The following sections are included: * Introduction * Breakdown of symmetry * Symmetry in the high-temperature region * Breakdown of symmetry for ferromagnetic systems * Breakdown of symmetry for frustrated systems * Stacked triangular antiferromagnetic lattices * bct helimagnets * Stacked J1-J2 square lattices * The simple cubic J1-J2 lattice * J1-J2-J3 lattice * Villain lattice and fully frustrated simple cubic lattice * Face-centered cubic lattice (fcc) * Hexagonal-close-packed lattice (hcp) * Pyrochlores * Other lattices * STAR lattices * Dihedral lattices VN,2 * Right-handed trihedral lattices V3,3 * P-hedral lattices VN,P * Ising and Potts-VN,1 model * Ising and Potts-N,2 model * Landau-Ginzburg model * Cubic term in Hamiltonian * Summary * Phase transitions between two and four dimensions: 2 Potts model * O(N)/O(N - P) breakdown of symmetry for d = 3 * Z2 ⊗ SO(N)/SO(N - 1) breakdown of symmetry for d = 3 * Z3 ⊗ SO(N)/SO(N - 1) breakdown of symmetry for d = 3 * Zq ⊗ O(N)/O(N - 2) and other breakdown of symmetry in d = 3 * Conclusion * O(N) frustrated vector spins in d = 2 * Introduction * Non frustrated XY spin systems * Frustrated XY spin systems: Z2 ⊗ SO(2) * Frustrated XY spin systems: Z3 ⊗ SO(2) * Frustrated XY spin systems: Z2 ⊗ Z2 ⊗ SO(2) and Z3 ⊗ Z2 ⊗ SO(2) * Frustrated Heisenberg spin systems: SO(3) * Frustrated Heisenberg spin systems: Z2 ⊗ SO(3), Z3 ⊗ SO(3) … * Topological defects for N ≥ 4 * General conclusions * Acknowledgments * Appendix A: Monte Carlo simulation * Appendix B: Renormalization group: Landau-Ginzburg theory, expansions in fixed dimension d = 3 and for d = 4 - ɛ and its implications for experiments * References

  13. Quantitative isothermal phase-field simulations of peritectic phase transformation in FeMn system

    Directory of Open Access Journals (Sweden)

    Celso Luiz Moraes Alves

    2016-01-01

    Full Text Available The present investigation shows quantitative results for the peritectic phase transformation of FeMn alloys utilizing phase-field simulations in 1-D and 2-D. The phase-field method used was based on an adaptation of the proposal of Folch and Plapp [Phys. Rev. E, 2005, 72, 011602] for the eutectic reaction. The two stages of peritectic phase transformation, the peritectic reaction and the peritectic transformation, were investigated numerically utilizing this phase-field approach. The evolution of the phases was quantitatively analyzed during the peritectic transformation and the fractions of the phases at the end of the solidification were compared with the thermodynamic equilibrium, defined by the phase diagram, for the case of 1-D simulation with peritectic concentration. An assessment of the behavior of the concentration gradient in the γ-phase (the peritectic phase through time was also carried out and a mathematical function which describes the γ-phase thickness evolution was defined. Finally, 2-D simulations were performed to clearly identify the two stages of the peritectic phase transformation. The obtained results show two main facts: (1 the numerical model is able to simulate quantitatively this phase transformation; and, (2 this numerical tool can be utilized for investigating quantitatively some aspects (normally determined indirectly that are difficult to be determined by direct measurements in experimental works.

  14. Automatic phase control in solar power satellite systems

    Science.gov (United States)

    Lindsey, W. C.; Kantak, A. V.

    1978-01-01

    Various approaches to the problem of generating, maintaining and distributing a coherent, reference phase signal over a large area are suggested, mathematically modeled and analyzed with respect to their ability to minimize: phase build-up, beam diffusion and beam steering phase jitter, cable length, and maximize power transfer efficiency. In addition, phase control configurations are suggested which alleviate the need for layout symmetry.

  15. Photovoltaic stand-alone modular systems, phase 2

    Science.gov (United States)

    Naff, G. J.; Marshall, N. A.

    1983-01-01

    The final hardware and system qualification phase of a two part stand-alone photovoltaic (PV) system development is covered. The final design incorporated modular, power blocks capable of expanding incrementally from 320 watts to twenty kilowatts (PK). The basic power unit (PU) was nominally rated 1.28 kWp. The controls units, power collection buses and main lugs, electrical protection subsystems, power switching, and load management circuits are housed in a common control enclosure. Photo-voltaic modules are electrically connected in a horizontal daisy-chain method via Amp Solarlok plugs mating with compatible connectors installed on the back side of each photovoltaic module. A pair of channel rails accommodate the mounting of the modules into a frameless panel support structure. Foundations are of a unique planter (tub-like) configuration to allow for world-wide deployment without restriction as to types of soil. One battery string capable of supplying approximately 240 ampere hours nominal of carryover power is specified for each basic power unit. Load prioritization and shedding circuits are included to protect critical loads and selectively shed and defer lower priority or noncritical power demands. The baseline system, operating at approximately 2 1/2 PUs (3.2 kW pk.) was installed and deployed. Qualification was successfully complete in March 1983; since that time, the demonstration system has logged approximately 3000 hours of continuous operation under load without major incident.

  16. First-principles calculation of phase equilibria and phase separation of the Fe-Ni alloy system

    Institute of Scientific and Technical Information of China (English)

    Ying Chen; Shuichi Iwata; Tetsuo Mohri

    2006-01-01

    Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the L12 phase at 1:3 stoichiometry, which is in agreement with the experimental result,and predicted the existence of L10 as a stable phase below 550 K; this L10 phase has been missing in the conventional phasediagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L10 and L12 order-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion (CTE) is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.

  17. National Geoscience Data Repository System: Phase 2 final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-01

    The American Geological Institute (AGI) has completed Phase 2 of a project to establish a National Geoscience Data Repository System (NGDRS). The project`s primary objectives are to preserve geoscience data in jeopardy of being destroyed and to make that data available to those who have a need to use it in future investigations. These data are available for donation to the public as a result of the downsizing that has occurred in the major petroleum and mining companies in the US for the past decade. In recent years, these companies have consolidated domestic operations, sold many of their domestic properties and relinquished many of their leases. The scientific data associated with those properties are no longer considered to be useful assets and are consequently in danger of being lost forever. The national repository project will make many of these data available to the geoscience community for the first time. Phase 2 encompasses the establishment of standards for indexing and cataloging of geoscience data and determination of the costs of transferring data from the private sector to public-sector data repositories. Pilot projects evaluated the feasibility of the project for transfer of different data types and creation of a Web-based metadata supercatalog and browser. Also as part of the project, a national directory of geoscience data repositories was compiled to assess what data are currently available in existing facilities. The next step, Phase 3, will focus on the initiation of transfer of geoscience data from the private sector to the public domain and development of the web-based Geotrek metadata supercatalog.

  18. A parametric LTR solution for discrete-time systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Jannerup, Ole Erik

    1989-01-01

    and the full loop transfer function, is manipulated into a general form involving the target loop transfer matrix and the fundamental recovery matrix. A parametric LTR solution based on the recovery matrix is developed. It is shown that the LQR/LTR (linear quadratic Gaussian/loop transfer recovery) solution......A parametric LTR (loop transfer recovery) solution for discrete-time compensators incorporating filtering observers which achieve exact recovery is presented for both minimum- and non-minimum-phase systems. First the recovery error, which defines the difference between the target loop transfer...

  19. Methods, systems and apparatus for synchronous current regulation of a five-phase machine

    Science.gov (United States)

    Gallegos-Lopez, Gabriel; Perisic, Milun

    2012-10-09

    Methods, systems and apparatus are provided for controlling operation of and regulating current provided to a five-phase machine when one or more phases has experienced a fault or has failed. In one implementation, the disclosed embodiments can be used to synchronously regulate current in a vector controlled motor drive system that includes a five-phase AC machine, a five-phase inverter module coupled to the five-phase AC machine, and a synchronous current regulator.

  20. Rooftop PV system. Final technical progress report, Phase II

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-08-01

    Under this four-year PV:BONUS Program, ECD and United Solar are developing and demonstrating two new lightweight flexible building integrated Photovoltaic (BIPV) modules specifically designed as exact replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and address the even larger roofing replacement market. The modules are designed to be installed by roofing contractors without special training which minimizes the installation and balance of system costs. The modules will be fabricated from high-efficiency, multiple-junction a-Si alloy solar cells developed by ECD and United Solar. Under the Phase I Program, which ended in March 1994, we developed two different concept designs for rooftop PV modules: (1) the United Solar overlapping (asphalt shingle replacement) shingle-type modules and (2) the ECD metal roof-type modules. We also developed a plan for fabricating, testing and demonstrating these modules. Candidate demonstration sites for our rooftop PV modules were identified and preliminary engineering designs for these demonstrations were developed; a marketing study plan was also developed. The major objectives of the Phase II Program, which started in June 1994 was (1) to develop, test, and qualify these new rooftop modules; (2) to develop mechanical and electrical engineering specifications for the demonstration projects; and (3) to develop a marketing/commercialization plan.

  1. HESTIA Phase I Test Results: The Air Revitalization System

    Science.gov (United States)

    Wright, Sarah E.; Hansen, Scott W.

    2016-01-01

    In any human spaceflight mission, a number of Environmental Control & Life Support System (ECLSS) technologies work together to provide the conditions astronauts need to live healthily, productively, and comfortably in space. In a long-duration mission, many of these ECLSS technologies may use materials supplied by In-Situ Resource Utilization (ISRU), introducing more interactions between systems. The Human Exploration Spacecraft Test-bed for Integration & Advancement (HESTIA) Project aims to create a test-bed to evaluate ECLSS and ISRU technologies and how they interact in a high-fidelity, closed-loop, human-rated analog habitat. Air purity and conditioning are essential components within any ECLSS and for HESTIA's first test they were achieved with the Air Revitalization System (ARS) described below. The ARS provided four essential functions to the test-bed chamber: cooling the air, removing humidity from the air, removing trace contaminants, and scrubbing carbon dioxide (CO2) from the air. In this case, the oxygen supply function was provided by ISRU. In the current configuration, the ARS is a collection of different subsystems. A fan circulates the air, while a condensing heat exchanger (CHX) pulls humidity out of the air. A Trace Contaminant Removal System (TCRS) filters the air of potentially harmful contaminants. Lastly, a Reactive Plastic Lithium Hydroxide (RP-LiOH) unit removes CO2 from the breathing air. During the HESTIA Phase I test in September 2015, the ARS and its individual components each functioned as expected, although further analysis is underway. During the Phase I testing and in prior bench-top tests, the energy balance of heat removed by the CHX was not equal to the cooling it received. This indicated possible instrument error and therefore recalibration of the instruments and follow-up testing is planned in 2016 to address the issue. The ARS was tested in conjunction with two other systems: the Human Metabolic Simulator (HMS) and the

  2. Single Phase Bidirectional PWM Converter for Microgrid System

    Directory of Open Access Journals (Sweden)

    C.Kalavalli

    2013-06-01

    Full Text Available Smart grid is a newly flourishing research area because of its viable applications and expected to address the drawback of existing grid. Microgrids are the part of the Smart grid and they are designed to supply electricity for a small community such as residential areas, universities or industrial sites. Power electronics plays a vital role for connecting the renewable energy sources to Microgrid system. This paper deals the Microgrid connected single phase Bidirectional PWM converter which operates in Rectification and Inverting mode. This converter helps to connect renewable energy sources to loads as well as excess power are given to power grid. Double Loop PID control technique is used for controlling the converter for both modes. The designed Converter is simulated in MATLAB/Simulink software and results are verified using the Hardware.

  3. Transient thermohydraulic modeling of two-phase fluid systems

    Science.gov (United States)

    Blet, N.; Delalandre, N.; Ayel, V.; Bertin, Y.; Romestant, C.; Platel, V.

    2012-11-01

    This paper presents a transient thermohydraulic modeling, initially developed for a capillary pumped loop in gravitational applications, but also possibly suitable for all kinds of two-phase fluid systems. Using finite volumes method, it is based on Navier-Stokes equations for transcribing fluid mechanical aspects. The main feature of this 1D-model is based on a network representation by analogy with electrical. This paper also proposes a parametric study of a counterflow condenser following the sensitivity to inlet mass flow rate and cold source temperature. The comparison between modeling results and experimental data highlights a good numerical evaluation of temperatures. Furthermore, the model is able to represent a pretty good dynamic evolution of hydraulic variables.

  4. Low energy scattering phase shifts for meson-baryon systems

    CERN Document Server

    Detmold, William

    2015-01-01

    In this work, we calculate meson-baryon scattering phase shifts in four channels using lattice QCD methods. From a set of calculations at four volumes, corresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of m_pi ~ 390 MeV, we determine the scattering lengths and effective ranges for these systems at the corresponding quark masses. We also perform the calculation at a lighter quark mass, m_pi ~ 230 MeV, on the largest volume. Using these determinations, along with those in previous work, we perform a chiral extrapolation of the scattering lengths to the physical point after correcting for the effective range contributions using the multi-volume calculations performed at m_pi ~ 390 MeV.

  5. FPGA-based prototype storage system with phase change memory

    Science.gov (United States)

    Li, Gezi; Chen, Xiaogang; Chen, Bomy; Li, Shunfen; Zhou, Mi; Han, Wenbing; Song, Zhitang

    2016-10-01

    With the ever-increasing amount of data being stored via social media, mobile telephony base stations, and network devices etc. the database systems face severe bandwidth bottlenecks when moving vast amounts of data from storage to the processing nodes. At the same time, Storage Class Memory (SCM) technologies such as Phase Change Memory (PCM) with unique features like fast read access, high density, non-volatility, byte-addressability, positive response to increasing temperature, superior scalability, and zero standby leakage have changed the landscape of modern computing and storage systems. In such a scenario, we present a storage system called FLEET which can off-load partial or whole SQL queries to the storage engine from CPU. FLEET uses an FPGA rather than conventional CPUs to implement the off-load engine due to its highly parallel nature. We have implemented an initial prototype of FLEET with PCM-based storage. The results demonstrate that significant performance and CPU utilization gains can be achieved by pushing selected query processing components inside in PCM-based storage.

  6. Intrachannel cross-phase modulation-induced phase shift in high-speed dispersion-managed optical fiber transmission system

    Science.gov (United States)

    Syed, Nitu; Faisal, Mohammad

    2013-12-01

    We investigate the intrachannel cross-phase modulation (IXPM)-induced phase shift in optical return-to-zero pulse propagating in a periodically dispersion-managed long-haul optical fiber transmission line. Necessary dynamical equations for various pulse parameters have been derived using variational analysis to estimate the phase shift. These equations are solved by the Runge-Kutta method. The analytical result is verified by numerical simulation based on split-step Fourier method. We therefore explore the effects of various parameters, such as transmission distance, input power, duty cycle, dispersion map strength, and residual dispersion, on phase shift for a 40 Gb/s single-channel transmission system. We also check the impact of variation of bit rate on phase shift. We find that IXPM-induced phase shift can be mitigated by proper adjustment of dispersion management and different pulse parameters like duty cycle, dispersion map strength, and peak power.

  7. Phases of polymer systems in solution studied via molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Joshua Allen [Iowa State Univ., Ames, IA (United States)

    2009-05-01

    Polymers are amazingly versatile molecules with a tremendous range of applications. Our lives would be very different without them. There would be no multitudes of plastic encased electronic gizmos, no latex paint on the walls and no rubber tires, just to name a few of the many commonplace polymer materials. In fact, life as we know it wouldn’t exist without polymers as two of the most essential types of molecules central to cellular life, Proteins and DNA, are both polymers! [1] With their wide range of application to a variety of uses, polymers are still a very active field in basic research. Of particular current interest is the idea of combining polymers with inorganic particles to form novel composite materials. [2] As computers are becoming faster, they are becoming all the more powerful tools for modeling and simulating real systems. With recent advances in computing on graphics processing units (GPUs) [3–7], questions can now be answered via simulation that could not even be asked before. This thesis focuses on the use of computer simulations to model novel polymerinorganic composite systems in order to predict what possible phases can form and under what conditions. The goal is to provide some direction for future experiments and to gain a deeper understanding of the fundamental physics involved. Along the way, there are some interesting and essential side-tracks in the areas of equilibrating complicated phases and accelerating the available computer power with GPU computing, both of which are necessary steps to enable the study of polymer nanocomposites.

  8. Comprehensive study of CD compensation and carrier phase estimation in optical communication systems influenced by equalization enhanced phase noise

    CERN Document Server

    Xu, Tianhua; Popov, Sergei; Li, Jie; Sergeyev, Sergey; Friberg, Ari T; Liu, Tiegen; Zhang, Yimo

    2016-01-01

    The performance of long-haul coherent optical fiber transmission system is significantly affected by the equalization enhanced phase noise (EEPN), due to the interaction between the electronic dispersion compensation (EDC) and the laser phase noise. In this paper, we present a comprehensive study on different chromatic dispersion (CD) compensation and carrier phase recovery (CPR) approaches, in the n-level phase shift keying (n-PSK) and the n-level quadrature amplitude modulation (n-QAM) coherent optical transmission systems, considering the impacts of EEPN. Four CD compensation methods are considered: the time-domain equalization (TDE), the frequency-domain equalization (FDE), the least mean square (LMS) adaptive equalization are applied for EDC, and the dispersion compensating fiber (DCF) is employed for optical dispersion compensation (ODC). Meanwhile, three carrier phase recovery methods are also involved: a one-tap normalized least mean square (NLMS) algorithm, a block-wise average (BWA) algorithm, and a...

  9. Phase correction on FPGA for TOTEM clock distribution system

    CERN Document Server

    Bellina, Alessandra

    2017-01-01

    A phase correction module has been implemented on FPGA, to control the delay of the clock at TOTEM timing detectors. The module consists of two parts: a phase shifter and a phase detector. The design of the phase shifter has been completed and was tested in the laboratory. The output jitter was measured and met the requirements. The phase detector design has also been completed and tested with a behavioural simulation, which outlined some weaknesses due to intrinsic limitations of FPGAs. The obtained resolution, although below ns scale, could not satisfy the requirements. A discussion on how to improve the performance of the phase detector is included.

  10. Crystal growth in a three-phase system: diffusion and liquid-liquid phase separation in lysozyme crystal growth.

    Science.gov (United States)

    Heijna, M C R; van Enckevort, W J P; Vlieg, E

    2007-07-01

    In the phase diagram of the protein hen egg-white lysozyme, a region is present in which the lysozyme solution demixes and forms two liquid phases. In situ observations by optical microscopy show that the dense liquid droplets dissolve when crystals grow in this system. During this process the demixed liquid region retracts from the crystal surface. The spatial distribution of the dense phase droplets present special boundary conditions for Fick's second law for diffusion. In combination with the cylindrical symmetry provided by the kinetically roughened crystals, this system allows for a full numerical analysis. Using experimental data for setting the boundary conditions, a quasi-steady-state solution for the time-dependent concentration profile was shown to be valid. Comparison of kinetically rough growth in a phase separated system and in a nonseparated system shows that the growth kinetics for a three-phase system differs from a two-phase system, in that crystals grow more slowly but the duration of growth is prolonged.

  11. APE: the Active Phasing Experiment to test new control system and phasing technology for a European Extremely Large Optical Telescope

    Science.gov (United States)

    Gonte, F.; Yaitskova, N.; Derie, F.; Constanza, A.; Brast, R.; Buzzoni, B.; Delabre, B.; Dierickx, P.; Dupuy, C.; Esteves, R.; Frank, C.; Guisard, S.; Karban, R.; Koenig, E.; Kolb, J.; Nylund, M.; Noethe, L.; Surdej, I.; Courteville, A.; Wilhelm, R.; Montoya, L.; Reyes, M.; Esposito, S.; Pinna, E.; Dohlen, K.; Ferrari, M.; Langlois, M.

    2005-08-01

    The future European Extremely Large Telescope will be composed of one or two giant segmented mirrors (up to 100 m of diameter) and of several large monolithic mirrors (up to 8 m in diameter). To limit the aberrations due to misalignments and defective surface quality it is necessary to have a proper active optics system. This active optics system must include a phasing system to limit the degradation of the PSF due to misphasing of the segmented mirrors. We will present the lastest design and development of the Active Phasing Experiment that will be tested in laboratory and on-sky connected to a VLT at Paranal in Chile. It includes an active segmented mirror, a static piston plate to simulate a secondary segmented mirror and of four phasing wavefront sensors to measure the piston, tip and tilt of the segments and the aberrations of the VLT. The four phasing sensors are the Diffraction Image Phase Sensing Instrument developed by Instituto de Astrofisica de Canarias, the Pyramid Phasing Sensor developed by Arcetri Astrophysical Observatory, the Shack-Hartmann Phasing Sensor developed by the European Southern Observatory and the Zernike Unit for Segment phasing developed by Laboratoire d'Astrophysique de Marseille. A reference measurement of the segmented mirror is made by an internal metrology developed by Fogale Nanotech. The control system of Active Phasing Experiment will perform the phasing of the segments, the guiding of the VLT and the active optics of the VLT. These activities are included in the Framework Programme 6 of the European Union.

  12. Phase transitions of ε-HNIW in compound systems

    Directory of Open Access Journals (Sweden)

    Jing-yuan Zhang

    2016-05-01

    Full Text Available The heat-induced phase transitions of ε-HNIW, both neat and coated with various additives used in plastic bonded explosives, were investigated using powder X-ray diffraction and differential scanning calorimetry. It was found that ε-HNIW, after being held at 70°C for 60h, remained in the ε-phase. Applying other conditions, various phase transition parameters were determined, including Tc (the critical phase transition temperature, T50 (the temperature at which 50% of the phase transition is complete and T180 (the percentage of γ-HNIW present in samples heated to 180°C. According to the above three parameters, additives were divided into three categories: those that delay phase transition, those that raise the critical temperature and the transition rate, and those that promote the phase transition. Based on the above data, a phase transition mechanism is proposed.

  13. Multifragmentation of heavy systems: partitions and phase transition signals; Multifragmentation de systemes lourds: partitions et signaux de transition de phases

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, E

    2006-09-15

    This work studies mononuclear systems produced in heavy ion collisions with large (peripheral: Au+Au) and small (central: Xe+Sn et Gd+U) impact parameters. These two classes of collisions need specific selections in order to isolate sources in thermal equilibrium (quasi-projectiles and quasi-fusion sources). We perform analyses on the statistical ensembles of events obtained after those selections to evidence phase transition signatures. First, a bimodal behaviour of the biggest fragment (Z{sub 1}) distribution, in peripheral collisions, is related to an order parameter using a renormalisation with an equiprobable excitation energy (E{sup *}) distribution constraint. A comparison with a canonical ensemble gives us information on the coexistence region location. Then, we compare static and dynamical properties of fragments produced by these sources in peripheral and central collisions. Differences on fragment multiplicities and charge asymmetry of partitions are observed. They find their origins in the presence or not of a velocity field mostly related to collective radial expansion during fragment formation. Analyses of the signal related to abnormal fluctuations of configurational energies and of the fossil signal related to spinodal decomposition for Au quasi-projectiles are performed to establish a link with the same signals already observed for central collisions. Finally, the location of events of the two types of sources in the E{sup *} - Z{sub 1} plane, are compared with a phase diagram, particularly the boundaries of the coexistence region deduced from the previous signals. (author)

  14. Predictions of the Pt(8)Ti phase in unexpected systems.

    Science.gov (United States)

    Taylor, Richard H; Curtarolo, Stefano; Hart, Gus L W

    2010-05-19

    The binary A(8)B phase (prototype Pt(8)Ti) has been experimentally observed in 11 systems. A high-throughput search over all the binary transition intermetallics, however, reveals 59 occurrences of the A(8)B phase: Au(8)Zn(dagger), Cd(8)Sc(dagger), Cu(8)Ni(dagger), Cu(8)Zn(dagger), Hg(8)La, Ir(8)Os(dagger), Ir(8)Re, Ir(8)Ru(dagger), Ir(8)Tc, Ir(8)W(dagger), Nb(8)Os(dagger), Nb(8)Rh(dagger), Nb(8)Ru(dagger), Nb(8)Ta(dagger), Ni(8)Fe, Ni(8)Mo(dagger)*, Ni(8)Nb(dagger)*, Ni(8)Ta*, Ni(8)V*, Ni(8)W, Pd(8)Al(dagger), Pd(8)Fe, Pd(8)Hf, Pd(8)Mn, Pd(8)Mo*, Pd(8)Nb, Pd(8)Sc, Pd(8)Ta, Pd(8)Ti, Pd(8)V*, Pd(8)W*, Pd(8)Zn, Pd(8)Zr, Pt(8)Al(dagger), Pt(8)Cr*, Pt(8)Hf, Pt(8)Mn, Pt(8)Mo, Pt(8)Nb, Pt(8)Rh(dagger), Pt(8)Sc, Pt(8)Ta, Pt(8)Ti*, Pt(8)V*, Pt(8)W, Pt(8)Zr*, Rh(8)Mo, Rh(8)W, Ta(8)Pd, Ta(8)Pt, Ta(8)Rh, V(8)Cr(dagger), V(8)Fe(dagger), V(8)Ir(dagger), V(8)Ni(dagger), V(8)Pd, V(8)Pt, V(8)Rh, and V(8)Ru(dagger) ((dagger) = metastable, * = experimentally observed). This is surprising for the wealth of new occurrences that are predicted, especially in well-characterized systems (e.g., Cu-Zn). By verifying all experimental results while offering additional predictions, our study serves as a striking demonstration of the power of the high-throughput approach. The practicality of the method is demonstrated in the Rh-W system. A cluster-expansion-based Monte Carlo model reveals a relatively high order-disorder transition temperature.

  15. Ternary Phases (Heusler) in the System Ti-Co-Sn

    Science.gov (United States)

    Kosinskiy, Andrey; Karlsen, Ole Bjørn; Sørby, Magnus H.; Prytz, Øystein

    2016-09-01

    Some of the Heusler-phases (XY 2 Z and XYZ) are known to have large homogeneity ranges which can be useful for tuning material properties. In this work, we have revised the isothermal section of the Ti-Co-Sn system at 973 K (700 °C). A total of 29 ternary compositions, mostly in the regions TiCo2-x Sn for 0 ≤ x ≤ 1 and Ti1+y Co2Sn1-y for 0 ≤ y ≤ 1, were prepared by arc-melting, then ball-milled and annealed. The resulting annealed powder samples were studied by applying the Rietveld method to X-ray and neutron powder diffraction data. Half-Heusler TiCoSn was not observed. The Heusler phase observed in TiCo2-x Sn has compositions ranging from TiCo1.52Sn to TiCo2Sn and has the half-Heusler structure where the excess of Co is located on the semi-filled tetrahedral site 4d (¾, ¾, ¾) in the space group F-43m. At 1273 K (1000 °C), this solid solubility is expanded from TiCo2Sn to TiCo with full solid solubility where Ti is gradually replacing Sn (Ti1+y Co2Sn1-y for 0 ≤ y ≤ 1), while at 973 K (700 °C) there is a small solubility gap for 0.0 ≤ y ≤ 0.2.

  16. Phase behavior and molecular dynamics simulation studies of new aqueous two-phase separation systems induced by HEPES buffer.

    Science.gov (United States)

    Taha, Mohamed; Khoiroh, Ianatul; Lee, Ming-Jer

    2013-01-17

    Here, for the first time, we show that with addition of a biological buffer, 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES), into aqueous solutions of tetrahydrofuran (THF), 1,3-dioxolane, 1,4-dioxane, 1-propanol, 2-propanol, tert-butanol, acetonitrile, or acetone, the organic solvent can be excluded from water to form a new liquid phase. The phase diagrams have been determined at ambient temperature. In order to understand why and how a zwitterion solute (HEPES) induced phase separation of the investigated systems, molecular dynamics (MD) simulation studies are performed for HEPES + water + THF system. The MD simulations were conducted for the aqueous mixtures with 12 different compositions. The reliability of the simulation results of HEPES in pure water and beyond the phase separation mixtures was justified by comparing the densities obtained from MD with the experimental values. The simulation results of HEPES in pure THF and in a composition inside the phase separation region were justified qualitatively. Interestingly, all HEPES molecules entirely aggregated in pure THF. This reveals that HEPES is insoluble in pure THF, which is consistent with the experimental results. Even more interestingly, the MD simulation for the mixture with composition inside the phase separation region showed the formation of two phases. The THF molecules are squeezed out from the water network into a new liquid phase. The hydrogen bonds (HBs), HB lifetime, HB Gibbs energy (ΔG), radial distribution functions (RDFs), coordination numbers (CNs), electrostatic interactions, and the van der Waals interactions between the different species have been analyzed. Further, MD simulations for the other phase separation systems by choosing a composition inside the two liquids region for each system were also simulated. Our findings will therefore pave the way for designing new benign separation auxiliary agents.

  17. Ultrafast Phase Comparator for Phase-Locked Loop-Based Optoelectronic Clock Recovery Systems

    DEFF Research Database (Denmark)

    Gomez-Agis, F.; Oxenløwe, Leif Katsuo; Kurimura, S.

    2009-01-01

    The authors report on a novel application of a chi((2)) nonlinear optical device as an ultrafast phase comparator, an essential element that allows an optoelectronic phase-locked loop to perform clock recovery of ultrahigh-speed optical time-division multiplexed (OTDM) signals. Particular interest...

  18. Phase equilibria in fluid mixtures at high pressures: The He-CH4 system

    Science.gov (United States)

    Streett, W. B.; Erickson, A. L.; Hill, J. L. E.

    1972-01-01

    An experimental study of phase equilibria in the He-CH4 system was carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These results, together with those recently obtained for other binary systems, provide information about the form of phase diagrams for binary gas mixtures in the region of pressure induced phase transitions at high pressures. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.

  19. Living between two worlds: two-phase culture systems for producing plant secondary metabolites.

    Science.gov (United States)

    Malik, Sonia; Hossein Mirjalili, Mohammad; Fett-Neto, Arthur Germano; Mazzafera, Paulo; Bonfill, Mercedes

    2013-03-01

    The two-phase culture system is an important in vitro strategy to increase the production of secondary metabolites (SMs) by providing an enhanced release of these compounds from plant cells. Whereas the first phase supports cell growth, the second phase provides an additional site or acts as a metabolic sink for the accumulation of SMs and also reduces feedback inhibition. This review is focused on several aspects of the two-phase culture system and aims to show the diverse possibilities of employing this technique for the in vitro production of SMs from plant cells. Depending on the material used in the secondary phase, two-phase culture systems can be broadly categorised as liquid-liquid or liquid-solid. The choice of material for the second phase depends on the type of compound to be recovered and the compatibility with the other phase. Different factors affecting the efficiency of two-phase culture systems include the choice of material for the secondary phase, its concentration, volume, and time of addition. Factors such as cell elicitation, immobilization, and permeabilization, have been suggested as important strategies to make the two-phase culture system practically reliable on a commercial scale. Since there are many possibilities for designing a two-phase system, more detailed studies are needed to broaden the range of secondary phases compatible with the various plant species producing SMs with potential applications, mainly in the food and pharmacology industries.

  20. Procedure for tracking manoeuvring targets with a multi-purpose phased-array radar system

    NARCIS (Netherlands)

    Navarro, A.M.

    1977-01-01

    This paper describes a tracking procedure for the FUCAS-experimental multi purpose phased array system. A phased array systems is always very complex. Upto this moment there are just a few systems, the results of experiments with those systems are not yet available. FUCAS is developed to acquire

  1. Procedure for tracking manoeuvring targets with a multi-purpose phased-array radar system

    NARCIS (Netherlands)

    Navarro, A.M.

    1977-01-01

    This paper describes a tracking procedure for the FUCAS-experimental multi purpose phased array system. A phased array systems is always very complex. Upto this moment there are just a few systems, the results of experiments with those systems are not yet available. FUCAS is developed to acquire exp

  2. Magnetoelectric phenomena in single-phase and composite systems

    Directory of Open Access Journals (Sweden)

    Mitoseriu, Liliana

    2005-06-01

    Full Text Available In the present review, the main phenomenology and problematic related some of the most interesting magnetoelectric systems (materials having in the same phase magnetic and ferroelectric order and interaction between them, giving rise to the magnetoelectric effect is presented. Some single-phase systems as manganites, BiFeO3 and relaxor magnetoelectrics mainly interesting from a fundamental point of view, as well as diphasic composites with a high potentiality in applications are discussed. The coupling between ferroelectric and magnetic activity in magnetoelectric multiferroics opens the possibility of controlling magnetic properties through electric fields and vice versa, giving to these materials a large potentiality for applications in spintronics, multiple state memory elements or novel memory devices which might use electric and/or magnetic fields for read/write operations.

    En esta revisión, se presentan la fenomenología y principales problemas relacionados con los sistemas magnetoeléctricos más interesantes. En el efecto magnetoeléctrico el orden magnético y ferroeléctrico se dan en una misma fase con interacción entre ellos. Se abordan sistemas monobásicos como manganitas, BiFeO3 y magnetoeléctricos relaxores y composites difásicos que poseen tanto un interés desde el punto de vista fundamental como un alto potencial de aplicaciones. El acoplamiento entre la actividad ferroeléctrica y magnética en multiferróicos magnetoeléctricos abre la posibilidad de controlar las propiedades magnéticas a través de campos eléctricos y viceversa, dotando a estos materiales de numerosas aplicaciones en espintrónica, elementos de memoria de estados múltiples o novedosas aplicaciones de memoria que pueden emplear campos eléctricos y/o magnéticos en operaciones de lectura/escritura.

  3. The Cu-Sb-Se phase system at temperatures between 350 and 700 degree C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven

    1999-01-01

    Phase relations were determined in the Cu-Sb-Se phase system at 300o, 400o, 450o, 500o, 600o and 700oC. Five three-component phases are present at 300oC: permingeatite (Cu3SbSe4), phase A (Cu3SbSe3, the Se-equivalent to skinnerite Cu3SbS3), phase B (CuSbSe2, the Se-equivalent to chalcostibite CuS...

  4. Nonlinear Phase Noise Compensation in Experimental WDM Systems with 256QAM

    DEFF Research Database (Denmark)

    Yankov, Metodi Plamenov; Da Ros, Francesco; Porto da Silva, Edson

    2016-01-01

    Nonlinear phase noise (NLPN) is studied in an experimental wavelength division multiplexed (WDM) system operating at 256QAM. Extremely narrow linewidth lasers (phase part of the nonlinear noise in a Raman amplified link. Based...

  5. Systems and Methods for Derivative-Free Adaptive Control

    Science.gov (United States)

    Yucelen, Tansel (Inventor); Kim, Kilsoo (Inventor); Calise, Anthony J. (Inventor)

    2015-01-01

    An adaptive control system is disclosed. The control system can control uncertain dynamic systems. The control system can employ one or more derivative-free adaptive control architectures. The control system can further employ one or more derivative-free weight update laws. The derivative-free weight update laws can comprise a time-varying estimate of an ideal vector of weights. The control system of the present invention can therefore quickly stabilize systems that undergo sudden changes in dynamics, caused by, for example, sudden changes in weight. Embodiments of the present invention can also provide a less complex control system than existing adaptive control systems. The control system can control aircraft and other dynamic systems, such as, for example, those with non-minimum phase dynamics.

  6. FPGA-based phase control of acousto-optic modulator Fourier synthesis system through gradient descent phase-locking algorithm.

    Science.gov (United States)

    Underwood, Kenneth J; Jones, Andrew M; Gopinath, Juliet T

    2015-06-20

    We present a new application of the stochastic parallel gradient descent (SPGD) algorithm to fast active phase control in a Fourier synthesis system. Pulses (4.9 ns) with an 80 MHz repetition rate are generated by feedback from a single phase-sensitive metric. Phase control is applied via fast current modulation of a tapered amplifier using an SPGD algorithm realized on a field-programmable gate array (FPGA). The waveforms are maintained by constant active feedback from the FPGA. We also discuss the extension of this technique to many more semiconductor laser emitters in a diode laser array.

  7. application to engine systems

    Directory of Open Access Journals (Sweden)

    G. George Zhu

    2000-01-01

    Full Text Available The q-Markov COVariance Equivalent Realization (q-Markov Cover method for identification uses either pulse, white noise or PRBS (Pseudo-Random Binary Signal as test excitation. This paper extended the q-Markov Cover using PRBS to the weighted multirate case, that is, the sample rate of the PRBS signal is different from the system output one. Then, the multirate PRBS q-Markov Cover is applied to identify a diesel engine model from the fuel command input to the engine speed output. The identified engine model has order of two and approximates the pure fuel system time delay using a first-order transfer function with a non-minimum phase numerator. Finally, the identified engine model was successfully used for designing engine idle speed governor and obtained satisfactory performance in the first try.

  8. Bioconversion of apigenin-7-O-β-glucoside in aqueous two-phase system

    OpenAIRE

    Ilić Sanja M.; Đaković Sanja D.; Cvejić Jelena H.; Antov Mirjana G.; Zeković Zoran P.

    2005-01-01

    The study is concerned with the conversion of apigenin-7-O-β-glucoside into apigenin in polyethylene glycol 6000 / dextran 20000 aqueous two-phase system by β-glucosidase. Apigenin was separated from apigenin-7-O-β-glucoside and β-glucosidase by their partition into opposite phases. In 14% PEG / 22.5% DEX aqueous two-phase system obtained yield of apigenin in top phase was 108%.

  9. Bioconversion of apigenin-7-O-β-glucoside in aqueous two-phase system

    Directory of Open Access Journals (Sweden)

    Ilić Sanja M.

    2005-01-01

    Full Text Available The study is concerned with the conversion of apigenin-7-O-β-glucoside into apigenin in polyethylene glycol 6000 / dextran 20000 aqueous two-phase system by β-glucosidase. Apigenin was separated from apigenin-7-O-β-glucoside and β-glucosidase by their partition into opposite phases. In 14% PEG / 22.5% DEX aqueous two-phase system obtained yield of apigenin in top phase was 108%.

  10. Conductivity, calorimetry and phase diagram of the NaHSO4–KHSO4 system

    DEFF Research Database (Denmark)

    Hind, Hamma-Cugny; Rasmussen, Søren Birk; Rogez, J.

    2006-01-01

    Physico-chemical properties of the binary system NaHSO4-KHSO4 were studied by calorimetry and conductivity, The enthalpy of mixing has been measured at 505 K in the full composition range and the phase diagram calculated. The phase diagram has also been constructed from phase transition temperatu......Physico-chemical properties of the binary system NaHSO4-KHSO4 were studied by calorimetry and conductivity, The enthalpy of mixing has been measured at 505 K in the full composition range and the phase diagram calculated. The phase diagram has also been constructed from phase transition...

  11. System modeling of the Thirty Meter Telescope alignment and phasing system

    Science.gov (United States)

    Dekens, Frank G.; Seo, Byoung-Joon; Troy, Mitchell

    2014-08-01

    We have developed a system model using the System Modeling Language (SysML) for the Alignment and Phasing System (APS) on the Thirty Meter Telescope (TMT). APS is a Shack-Hartmann wave-front sensor that will be used to measure the alignment and phasing of the primary mirror segments, and the alignment of the secondary and tertiary mirrors. The APS system model contains the ow-down of the Level 1 TMT requirements to APS (Level 2) requirements, and from there to the APS sub-systems (Level 3) requirements. The model also contains the operating modes and scenarios for various activities, such as maintenance alignment, post-segment exchange alignment, and calibration activities. The requirements ow-down is captured in SysML requirements diagrams, and we describe the process of maintaining the DOORS database as the single-source-of-truth for requirements, while using the SysML model to capture the logic and notes associated with the ow-down. We also use the system model to capture any needed communications from APS to other TMT systems, and between the APS sub-systems. The operations are modeled using SysML activity diagrams, and will be used to specify the APS interface documents. The modeling tool can simulate the top level activities to produce sequence diagrams, which contain all the communications between the system and subsystem needed for that activity. By adding time estimates for the lowest level APS activities, a robust estimate for the total time on-sky that APS requires to align and phase the telescope can be obtained. This estimate will be used to verify that the time APS requires on-sky meets the Level 1 TMT requirements.

  12. Unconventional geometric quantum phase gates with a cavity QED system

    Science.gov (United States)

    Zheng, Shi-Biao

    2004-11-01

    We propose a scheme for realizing two-qubit quantum phase gates via an unconventional geometric phase shift with atoms in a cavity. In the scheme the atoms interact simultaneously with a highly detuned cavity mode and a classical field. The atoms undergo no transitions during the gate operation, while the cavity mode is displaced along a circle in the phase space, aquiring a geometric phase conditional upon the atomic state. Under certain conditions, the atoms are disentangled with the cavity mode and thus the gate is insensitive to both the atomic spontaneous emission and the cavity decay.

  13. MARMOT Phase-Field Model for the U-Si System

    Energy Technology Data Exchange (ETDEWEB)

    Aagesen, Larry Kenneth [Idaho National Laboratory; Schwen, Daniel [Idaho National Laboratory

    2016-09-01

    A phase-field model for the U-Si system has been implemented in MARMOT. The free energies for the phases relevant to accident-tolerant fuel applications (U3Si2, USi, U3Si, and liquid) were implemented as free energy materials within MARMOT. A new three-phase phase-field model based on the concepts of the Kim-Kim-Suzuki two-phase model was developed and implemented in the MOOSE phase-field module. Key features of this model are that two-phase interfaces are stable with respect to formation of the third phase, and that arbitrary phase free energies can be used. The model was validated using a simplified three-phase system and the U-Si system. In the U-Si system, the model correctly reproduced three-phase coexistence in a U3Si2-liquid-USi system at the eutectic temperature, solidification of a three-phase mixture below the eutectic temperature, and complete melting of a three-phase mixture above the eutectic temperature.

  14. Phase transition in vortex system in Bi2212:Pb monocrystal

    CERN Document Server

    Uspenskaya, L S; Rakhmanov, A L

    2002-01-01

    Penetration of the magnetic flux into the (Bi sub 0 sub . sub 8 sub 4 Pb sub 0 sub . sub 1 sub 6) sub 2 sub . sub 2 Sr sub 2 CaCu sub 2 O sub 8 high-temperature superconductor monocrystal is studied thorough the magnetooptical method in the crossed magnetic fields. It is shown that the magnetic flux penetration in the low-temperature areas is anisotropic: it moves primarily along the magnetic field, applied in the sample plane, and this anisotropy grows with the temperature growth. At the temperature of T sub m = 54 +- 2 K there takes place sharp change in the character of the magnetic field penetration into the superconductor, whereby the direction of the flux motion discontinues to be dependent on the direction and value of the magnetic field applied in the sample plane. This effect is interpreted within the frames of representations on the phase transition in the vortex system connected with a sharp decrease in the correlations of the vortex position in the different CuO-planes

  15. ISOBUTANOL FROM SYNGAS IN A THREE PHASE SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Peter Tijrn

    2002-12-29

    With growing interest in oxygenates as octane booster for automotive fuels, various synthesis routes for these chemicals are being investigated. Among others, alternative routes to isobutene, the C4-components in MTBE-synthesis are under investigation. A promising path to isobutene is the heterogeneously catalyzed CO-hydrogenation to isobutanol with following dehydration (Fig. 1). As shown by thermodynamical studies, the heterogeneously catalyzed CO-hydrogenation to isobutanol is not expected to experience any thermodynamic constraints. However, heterogeneous hydrogenation of CO is a very exothermic process, a problem which can only be partly solved when being conducted in a plug flow reactor. When carried out in reaction vessels with moving catalyst bed (e.g. three phase stirred tank), heat transfer problems can be resolved, along with additional benefits connected with this reactor type. Several heterogeneous catalytic systems have been under investigation for their capability of isobutanol synthesis from syngas. Most promising catalysts for an active and selective isobutanol synthesis from CO are modified high temperature methanol catalysts.

  16. Robust terahertz self-heterodyne system using a phase noise compensation technique.

    Science.gov (United States)

    Song, Hajun; Song, Jong-In

    2015-08-10

    We propose and demonstrate a robust terahertz self-heterodyne system using a phase noise compensation technique. Conventional terahertz self-heterodyne systems suffer from degraded phase noise performance due to phase noise of the laser sources. The proposed phase noise compensation technique uses an additional photodiode and a simple electric circuit to produce phase noise identical to that observed in the terahertz signal produced by the self-heterodyne system. The phase noise is subsequently subtracted from the terahertz signal produced by the self-heterodyne system using a lock-in amplifier. While the terahertz self-heterodyne system using a phase noise compensation technique offers improved phase noise performance, it also provides a reduced phase drift against ambient temperature variations. The terahertz self-heterodyne system using a phase noise compensation technique shows a phase noise of 0.67 degree in terms of a standard deviation value even without using overall delay balance control. It also shows a phase drift of as small as approximately 10 degrees in an open-to-air measurement condition without any strict temperature control.

  17. Characterization of the system functions of ultrasonic linear phased array inspection systems.

    Science.gov (United States)

    Huang, Ruiju; Schmerr, Lester W

    2009-02-01

    This work characterizes the electrical and electromechanical aspects of an ultrasonic linear phased array inspection system, using a matrix of system functions that are obtained from the measured response of individual array elements in a simple reference experiment. It is shown that for the arrays tested all these system functions are essentially identical, allowing one to use a single system function to characterize the entire array, as done for an ordinary single element transducer. The variation of this single system function with the number of elements firing in the array or with changes of the delay law used is examined. It is also demonstrated that once such a single system function is obtained for an array, it can be used in a complete ultrasonic measurement model to accurately predict the array response measured from a reference reflector in an immersion setup.

  18. Use of piecewise polynomial phase modeling to compensate ionospheric phase contamination in skywave radar systems

    Institute of Scientific and Technical Information of China (English)

    Lu Kun; Liu Xingzhao

    2005-01-01

    Recognition and correction of ionospheric phase path contamination is a vital part of the global radar signal processing sequence. A number of model-based correction algorithms have been developed to deal with the radar performance degradation due to the ionospheric distortion and contamination. This paper addresses a novel parametric estimation and compensation method based on High-order Ambiguity Function (HAF) to solve the problem of phase path contamination of HF skywave radar signals. When signal-to-noise ratio and data sequence available satisfy the predefined conditions, the ionospheric phase path contamination may be modeled by a polynomial phase signal (PPS). As a new parametric tool for analyzing the PPS, HAF is introduced to estimate parameters of the polynomial-phase model and reconstruct the correction signal. Using the reconstructed correction signal, compensation can be performed before coherent integration so that the original echo spectrum can be restored. A piecewise scheme is proposed to track rapid variation of the phase contamination based on HAF method, and it can remove the Doppler spread effect caused by the ionos phere nonstationarity. Simulation and experimental results are given to demonstrate the efficiency of the proposed algorithm.

  19. Control of structure formation in phase-separating systems

    NARCIS (Netherlands)

    Singh, A.; Mukherjee, A.; Vermeulen, H.M.; Barkema, G.T.; Puri, S.

    2011-01-01

    In this paper, we study the evolution of phase-separating binary mixtures which are subjected to alternate cooling and heating cycles. An initially homogeneous mixture is rapidly quenched to a temperature T1 phase separation for a whil

  20. Development of Phase Lock Loop System for Synchronisation of a ...

    African Journals Online (AJOL)

    Akorede

    ABSTRACT: Phase locked loop (PLL) is an important part of the control unit of the grid connected power converter. The method of zero ... an output signal proportional to the phase difference between the input ... In their works, a proper PI regulator was designed ..... the course of this work for better performance analysis, it is.

  1. Exact phase space functional for two-body systems

    CERN Document Server

    Gracia-Bondía, José M

    2010-01-01

    The determination of the two-body density functional from its one-body density is achieved for Moshinsky's harmonium model, using a phase-space formulation, thereby resolving its phase dilemma. The corresponding sign rules can equivalently be obtained by minimizing the ground-state energy.

  2. Phase behaviour of tertiary recovery sulfonates - petroleum fractions - aqueous systems

    Energy Technology Data Exchange (ETDEWEB)

    Ghoniem, S.A.; Darwish, T.A.; Salamah, A.O.

    1988-02-01

    The phase behaviour of tertiary recovery sulfonates having commercial names TRS-10, TRS-16 and TRS-40 with aqueous phase and light petroleum fractions (non polar kerosene and gasoline) was studied at 20, 40 and 60/sup 0/C. The adopted pseudo components of the ternary diagram are hydrocarbon, surfactant and aqueous phase. The aqueous phase was composed of bidistilled water in addition to different proportions of pure alcohols and sodium chloride. The tested alcohols included methanol, ethanol, iso-propanol, n-butanol and n-pentanol. Thus, the best alcohol type and concentration in addition to optimum salinity, which correspond to maximum single phase region, were established for each surfactant at the various tested temperatures. It was shown that higher the affinity of the tested surfactant for hydrocarbon phase, the greater is the solubility of the corresponding optimum co-surfactant in water. The variation of optimum alcohol concentration with temperature, the effect of salt on the single phase region and the effect of hydrocarbon phase on the observed phenomena were discussed and found to agree with the previously established theories.

  3. Theory of phase-mixing amplification in an optomechanical system

    Science.gov (United States)

    Ockeloen-Korppi, C. F.; Heikkilä, T. T.; Sillanpää, M. A.; Massel, F.

    2017-09-01

    The investigation of the ultimate limits imposed by quantum mechanics on amplification represents an important topic both on a fundamental level and from the perspective of potential applications. We discuss here a novel regime for bosonic linear amplifiers—beside phase-insensitive and phase-sensitive amplification—which we term here phase-mixing amplification. Furthermore, we show that phase-mixing amplification can be realised in a cavity optomechanical setup, constituted by a mechanical resonator which is dispersively coupled to an optomechanical cavity asymmetrically driven around both mechanical sidebands. While, in general, this amplifier is phase-mixing, for a suitable choice of parameters, the amplifier proposed here operates as a phase-sensitive amplifier. We show that both configurations allow amplification with an added noise below the quantum limit of (phase-insensitive) amplification in a parameter range compatible with current experiments in microwave circuit optomechanics. In particular, we show that introducing phase-mixing amplification typically allows for a significant reduction of the added noise.

  4. Effects of mobile vacancies on the dynamics of ordering and phase separation in nonconserved multicomponent systems

    DEFF Research Database (Denmark)

    Gilhøj, Henriette; Jeppesen, Claus; Mouritsen, Ole G.

    1995-01-01

    The effects of mobile vacancies on the dynamics of ordering processes and phase separation in multicomponent systems are studied via Monte Carlo simulations of a two-dimensional seven-state ferromagnetic Potts model with varying degrees of site dilution. The model displays phase equilibria...... corresponding to a dilute Potts-disordered (fluid) phase and a dilute Potts-ordered phase (solid), as well as a broad region of coexistence between the fluid and the solid phase. Temperature quenches into the dilute Potts-ordered phase as well as into the phase-separated region are considered under...... the condition of conserved vacancy density and nonconserved Potts order. The dynamics of ordering and phase separation is found to follow algebraic growth laws with exponent values that depend on the phase to which the quench is performed. Strong transient effects are observed in the dilute Potts-ordered phase...

  5. Aqueous two-phase system based on natural quaternary ammonium compounds for the extraction of proteins.

    Science.gov (United States)

    Zeng, Chao-Xi; Xin, Rui-Pu; Qi, Sui-Jian; Yang, Bo; Wang, Yong-Hua

    2016-02-01

    Aqueous two-phase systems, based on the use of natural quaternary ammonium compounds, were developed to establish a benign biotechnological route for efficient protein separation. In this study, aqueous two-phase systems of two natural resources betaine and choline with polyethyleneglycol (PEG400/600) or inorganic salts (K2 HPO4 /K3 PO4 ) were formed. It was shown that in the K2 HPO4 -containing aqueous two-phase system, hydrophobic interactions were an important driving force of protein partitioning, while protein size played a vital role in aqueous two-phase systems that contained polyethylene glycol. An extraction efficiency of more than 90% for bovine serum albumin in the betaine/K2 HPO4 aqueous two-phase system can be obtained, and this betaine-based aqueous two-phase system provided a gentle and stable environment for the protein. In addition, after investigation of the cluster phenomenon in the betaine/K2 HPO4 aqueous two-phase systems, it was suggested that this phenomenon also played a significant role for protein extraction in this system. The development of aqueous two-phase systems based on natural quaternary ammonium compounds not only provided an effective and greener method of aqueous two-phase system to meet the requirements of green chemistry but also may help to solve the mystery of the compartmentalization of biomolecules in cells.

  6. Aircraft Performance Analysis in Conceptual Design Phase based on System-of-Systems Simulations

    Directory of Open Access Journals (Sweden)

    Tian Yifeng

    2016-01-01

    Full Text Available To obtain a competitive design in aircraft conceptual design phase, this paper propose an aircraft performance analysis method based on system-of-systems (SoS simulations. The analysis process includes design space exploration and mission effectiveness analysis and the stochastic nature in SoS mission is captured based on a Monte Carlo method. Meanwhile as an example, the performance of UAVs which are applied in earthquake search and rescue SoS is analysed based on SoS simulations. The results show that the level of aircraft performance which leads to an optimum SoS effectiveness could be designed below the maximum performance. And it is necessary to apply SoS simulations into aircraft conceptual design phase to help designers optimize aircraft performance.

  7. A robust optical phase modulated 60 GHz RoF WDM system

    DEFF Research Database (Denmark)

    Yu, Xianbin; Kozuch, Wojciech; Turkiewicz, Jaroslaw

    2010-01-01

    robust 4-channel WDM optical phase modulated 60GHz wireless fiber system is proposed and simulated. In this system, a Fabry-Perot (FP) frequency interleaver is designed to suppress optical carriers for 60GHz signal generation. The simulated results show that this phase modulated WDM system...

  8. Influence of ultrasonic condition on phase transfer catalyzed radical polymerization of methyl methacrylate in two phase system - A kinetic study.

    Science.gov (United States)

    Marimuthu, Elumalai; Murugesan, Vajjiravel

    2017-09-01

    An ultrasonic condition assisted phase transfer catalyzed radical polymerization of methyl methacrylate was investigated in an ethyl acetate/water two phase system at 60±1°C and 25kHz, 300W under inert atmosphere. The influence of monomer, initiator, catalyst and temperature, volume fraction of aqueous phase on the rate of polymerization was examined in detail. The reaction order was found to be unity for monomer, initiator and catalyst. Generally, the reaction rate was relatively fast in two phase system, when a catalytic amount of phase transfer catalyst was used. The combined approach, use of ultrasonic and PTC condition was significantly enhances the rate of polymerization. An ultrasonic and phase transfer catalyzed radical polymerization of methyl methacrylate has shown about three fold enhancements in the rate compared with silent polymerization of MMA using cetyltrimethylammonium bromide as PTC. The resultant kinetics was evaluated with silent polymerization and an important feature was discussed. The activation energy and other thermodynamic parameters were computed. Based on the obtained results an appropriate radical mechanism has been derived. TGA showed the polymer was stable up to 150°C. The FT-IR and DSC analysis validates the atactic nature of the obtained polymer. The XRD pattern reveals the amorphous nature of polymer was dominated. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Phase Resetting in an Asymptotically Phaseless System: On the Phase Response of Limit Cycles Verging on a Heteroclinic Orbit

    CERN Document Server

    Shaw, Kendrick M; Thomas, Peter J

    2011-01-01

    Rhythmic behaviors in neural systems often combine features of limit cycle dynamics (stability and periodicity) with features of near heteroclinic or near homoclinic cycle dynamics (extended dwell times in localized regions of phase space). Proximity of a limit cycle to one or more saddle equilibria can have a profound effect on the timing of trajectory components and response to both fast and slow perturbations, providing a possible mechanism for adaptive control of rhythmic motions. Reyn showed that for a planar dynamical system with a stable heteroclinic cycle (or separatrix polygon), small perturbations satisfying a net inflow condition will generically give rise to a stable limit cycle (Reyn, 1980; Guckenheimer and Holmes, 1983). Here we consider the asymptotic behavior of the infinitesimal phase response curve (iPRC) for examples of two systems satisfying Reyn's inflow criterion, (i) a smooth system with a chain of four hyperbolic saddle points and (ii) a piecewise linear system corresponding to local l...

  10. Phase equilibria calculation of LaI3-MI (M=Na, K, Cs) binary systems

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; SHAO Guoquan; LI Shaobo; SUN Yimin; QIAO Zhiyu

    2009-01-01

    The Gibbs energies of liquid phases in the LaI3-MI (M=Na, K, Cs) systems were described by the modified quasi-chemical model. From the measured phase equilibrium data of these binary systems, a set of thermodynamic functions were optimized by using the CAL-PHAD technique. The enthalpy of mixing and the interaction parameter of the liquid phase were predicted from known data for the LaI3-MI systems.

  11. Superuniversality of topological quantum phase transition and global phase diagram of dirty topological systems in three dimensions

    Science.gov (United States)

    Goswami, Pallab; Chakravarty, Sudip

    2017-02-01

    The quantum phase transition between two clean, noninteracting topologically distinct gapped states in three dimensions is governed by a massless Dirac fermion fixed point, irrespective of the underlying symmetry class, and this constitutes a remarkably simple example of superuniversality. For a sufficiently weak disorder strength, we show that the massless Dirac fixed point is at the heart of the robustness of superuniversality. We establish this by considering both perturbative and nonperturbative effects of disorder. The superuniversality breaks down at a critical strength of disorder, beyond which the topologically distinct localized phases become separated by a delocalized diffusive phase. In the global phase diagram, the disorder controlled fixed point where superuniversality is lost, serves as a multicritical point, where the delocalized diffusive and two topologically distinct localized phases meet and the nature of the localization-delocalization transition depends on the underlying symmetry class. Based on these features, we construct the global phase diagrams of noninteracting, dirty topological systems in three dimensions. We also establish a similar structure of the phase diagram and the superuniversality for weak disorder in higher spatial dimensions. By noting that 1 /r2 power-law correlated disorder acts as a marginal perturbation for massless Dirac fermions in any spatial dimension d , we have established a general renormalization group framework for addressing disorder driven critical phenomena for fixed spatial dimension d >2 .

  12. Relative hydrophobicity between the phases and partition of cytochrome-c in glycine ionic liquids aqueous two-phase systems.

    Science.gov (United States)

    Wu, Changzeng; Wang, Jianji; Li, Zhiyong; Jing, Jun; Wang, Huiyong

    2013-08-30

    In this work, glycine ionic liquids tetramethylammonium glycine ([N1111][Gly]), tetraethylammonium glycine ([N2222][Gly]), tetra-n-butylammonium glycine ([N4444][Gly]), tetra-n-butylphosphonium glycine ([P4444][Gly]) and tetra-n-pentylammonium glycine ([N5555][Gly]) were synthesized and used to prepare aqueous two-phase systems (ATPSs) in the presence of K2HPO4. Binodal curves of such ATPSs and partition coefficients of a series of dinitrophenylated (DNP) amino acids in these ATPSs were determined at 298.15K to understand the effect of cationic structure of the ionic liquids on the phase-forming ability of glycine ionic liquids, relative hydrophobicity between the phases in the ionic liquids ATPSs, and polarity of the ionic liquids-rich phases. With the attempt to correlate the relative hydrophobicity of the phases in the ATPSs with their extraction capability for proteins, partition coefficients of cytochrome-c in the ATPSs were also determined. It was shown that partition coefficients of cytochrome-c were in the range from 2.83 to 20.7 under the studied pH conditions. Then, hydrophobic interactions between cytochrome-c and the ionic liquid are suggested to be the main driving force for the preferential partition of cytochrome-c in the glycine ionic liquid-rich phases of the ATPSs. Result derived from polarity of the ionic liquids-rich phases supports this mechanism.

  13. Salt effect on the (polyethylene glycol 8000 + sodium sulfate) aqueous two-phase system: Relative hydrophobicity of the equilibrium phases

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Luisa A., E-mail: laferreira@deb.uminho.pt [IBB - Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Teixeira, Jose A. [IBB - Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2011-08-15

    Highlights: > Gibbs free energy of transfer of a methylene group on PEG 8000 - Na{sub 2}SO{sub 4} ATPS. > Influence of salt additive on the hydrophobic character of the coexisting phases. > Partitioning behavior of a series of five sodium salts of DNP-amino acids. > A relationship between {Delta}G(CH{sub 2}), TLL and I of the salt additive was established. - Abstract: The relative hydrophobicity of the phases of several {l_brace}polyethylene glycol (PEG) 8000 + sodium sulfate (Na{sub 2}SO{sub 4}){r_brace} aqueous two-phase systems (ATPSs), all containing 0.01 mol . L{sup -1} sodium phosphate buffer (NaPB, pH 7.4) and increasing concentration of a salt additive, NaCl or KCl, up to 1.0 mol . L{sup -1}, was measured by the free energy of transfer of a methylene group between the phases, {Delta}G(CH{sub 2}). The {Delta}G(CH{sub 2}) of the systems was determined by partitioning of a homologous series of five sodium salts of dinitrophenylated (DNP) - amino acids with aliphatic side chains in three different tie-lines of each biphasic system. The relative hydrophobicity of the phases ranged from -0.125 to -0.183 kcal . mol{sup -1}, being the NaCl salt the one to provide the more effective changes. The results show that, within each system, there is a linear relationship between the {Delta}G(CH{sub 2}) and the tie-line length (TLL), and biphasic systems with high salt additive concentration present the most negative {Delta}G(CH{sub 2}) values. Therefore, the feasibility of establishing a relationship between the relative hydrophobicity of the phases in a given TLL and the ionic strength of the salt additive was investigated and a satisfactory correlation was found for each salt.

  14. The analysis of magnesium oxide hydration in three-phase reaction system

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin, E-mail: ntp@dlmu.edu.cn

    2014-05-01

    In order to investigate the magnesium oxide hydration process in gas–liquid–solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid–solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH){sub 2} precipitation, Mg(OH){sub 2} peeling off from MgO particle and leaving behind fresh MgO surface. - Graphical abstract: There was existence of a peeling-off process in the gas–liquid–solid (three-phase) MgO hydration system. - Highlights: • Magnesium oxide hydration in gas–liquid–solid system was investigated. • The experimental data in three-phase system could be fitted well by two models. • The morphology analysis suggested that there was existence of a peel-off process.

  15. Enhanced Phase-Shifted Current Control for Harmonic Cancellation in Three-Phase Multiple Adjustable Speed Drive Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Davari, Pooya; Zare, Firuz

    2017-01-01

    A phase-shifted current control can be employed to mitigate certain harmonics induced by the Diode Rectifiers (DR) and Silicon-Controlled Rectifiers (SCR) as the front-ends of multiple parallel Adjustable Speed Drive (ASD) systems. However, the effectiveness of the phase-shifted control relies on......-shifted current control is a cost-effective solution to multiple ASD systems in terms of harmonic cancellation.......A phase-shifted current control can be employed to mitigate certain harmonics induced by the Diode Rectifiers (DR) and Silicon-Controlled Rectifiers (SCR) as the front-ends of multiple parallel Adjustable Speed Drive (ASD) systems. However, the effectiveness of the phase-shifted control relies...... on the loading condition of each drive unit as well as the number of drives in parallel. In order to enhance the harmonic cancellation by means of the phase-shifted current control, the currents drawn by the rectifiers should be maintained almost at the same level. Thus, this paper firstly analyzes the impact...

  16. Quantum and thermal phase escape in extended Josephson systems

    Energy Technology Data Exchange (ETDEWEB)

    Kemp, A.

    2006-07-12

    In this work I examine phase escape in long annular Josephson tunnel junctions. The sine-Gordon equation governs the dynamics of the phase variable along the junction. This equation supports topological soliton solutions, which correspond to quanta of magnetic flux trapped in the junction barrier. For such Josephson vortices an effective potential is formed by an external magnetic field, while a bias current acts as a driving force. Both together form a metastable potential well, which the vortex is trapped in. When the driving force exceeds the pinning force of the potential, the vortex escapes and the junction switches to the voltage state. At a finite temperature the driving force fluctuates. If the junction's energy scale is small, the phase variable can undergo a macroscopic quantum tunneling (MQT) process at temperatures below the crossover temperature. Without a vortex trapped, the metastable state is not a potential minimum in space, but a potential minimum at zero phase difference. (orig.)

  17. Phase transitions in the coal-water-methane system

    Energy Technology Data Exchange (ETDEWEB)

    Alexeev, A.D.; Ulyanova, E.V.; Kalugina, N.A.; Degtyar, S.E. [Institute of Physical & Mining Processes, Donetsk (Ukraine)

    2006-07-01

    Low temperature phase transitions in water and methane occurring in fossil coals were studied experimentally using Nuclear Magnetic Resonance (NMR) techniques. Contributions of constituent fluids into narrow line of {sup 1}H NMR wide line spectrum were analyzed.

  18. Wet Process Induced Phase Transited Drug Delivery System as a ...

    African Journals Online (AJOL)

    Nx 6110

    effect of varying osmotic pressure of the dissolution medium on drug release was studied. ... results of in vivo toxicity studies may support the use of phase transited ... ocular inflammatory conditions [16]. ... Flurbiprofen was obtained from Sun.

  19. Quantum Fourier Transform and Phase Estimation in Qudit System

    Institute of Scientific and Technical Information of China (English)

    CAO Ye; PENG Shi-Guo; ZHENG Chao; LONG Gui-Lu

    2011-01-01

    The quantum Fourier transform and quantum phase estimation are the key components for many quantum algorithms, such as order-finding, factoring, and etc.In this article, the general procedure of quantum Fourier transform and phase estimation are investigated for high dimensional case.They can be seen as subroutines in a main program run in a qudit quantum computer, and the quantum circuits are given.

  20. Associative recall in a volume holographic storage system based on phase-code multiplexing

    Science.gov (United States)

    Berger, G.; Denz, C.; Orlov, S. S.; Phillips, B.; Hesselink, L.

    2001-12-01

    We present two different techniques on how to realize a content-addressed holographic memory when using phase-code multiplexing, relying on simple intensity measurements rather than phase distributions. Theoretical and experimental results of associative recall in a phase-coded system designed for digital data storage will be presented and compared to the corresponding method when using angular multiplexing.

  1. Development of Automatic Phased Array Inspection System for Long-distance Pipeline

    Institute of Scientific and Technical Information of China (English)

    XueZhenkui; BaiShiwu; ZhanHua; XiaXin; XiangYang

    2004-01-01

    In the paper the development of phased array technique home and abroad is summarized, the overall structure and main research on phased array inspection system are introduced, and meanwhile the future field of study and development of phased array ultrasonic inspection technique is pointed out.

  2. Simulation of mm-wave signal generation using phase modulation in ROF system

    Institute of Scientific and Technical Information of China (English)

    ZHANG da-peng; YU Chong-xiu; XIN Xiang-jun; MA Jian-xin; ZHANG Jin-long

    2009-01-01

    The generation of optical millimeter waves via the improved phase modulator in a RoF system and the transmission char-acter of the signal are thenretically investigated. A new phase modulating scheme is proposed, in which the sidebands are separated by wave length demultiplexer and one of them doesn't feed digital signals, thereby the phase wake-off is restrained.

  3. Deconfinement Phase Transition in an Expanding Quark system in Relaxation Time Approximation

    CERN Document Server

    Yang, Z; Yang, Zhenwei; Zhuang, Pengfei

    2004-01-01

    We investigated the effects of nonequilibrium and collision terms on the deconfinement phase transition of an expanding quark system in Friedberg-Lee model in relaxation time approximation. By calculating the effective quark potential, the critical temperature of the phase transition is dominated by the mean field, while the collisions among quarks and mesons change the time structure of the phase transition significantly.

  4. Phase diagram of a three-sublattice mixed ferro-ferrimagnetic Heisenberg system

    Science.gov (United States)

    Mert, H. Şevki; Mert, Gülistan

    2013-10-01

    We present a numerical study of a three-sublattice mixed ferro-ferrimagnetic Heisenberg system. Green's function technique is used to calculate the magnetization as a function of temperature. The technique involves the random phase approximation and Anderson-Callen's decoupling. We obtain phase diagram and the first-order phase transition.

  5. High phase noise tolerant pilot-tone-aided DP-QPSK optical communication systems

    DEFF Research Database (Denmark)

    Zhang, Xu; Pang, Xiaodan; Deng, Lei

    2012-01-01

    In this paper we experimentally demonstrate a novel, high phase-noise tolerant, optical dual polarization (DP) quadrature phase-shift keying (QPSK) communication system based on pilot-tone-aided phase noise cancellation (PNC) algorithm. Vertical cavity surface emitting lasers (VCSELs...

  6. Predictive Modelling of Phase-Transfer Catalyst Systems for Improved and Innovative Design

    DEFF Research Database (Denmark)

    Anantpinijwatna, Amata; Hyung Kim, Sun; Sales-Cruz, Mauricio

    2016-01-01

    increasing attention as a novel organic synthesis option due to its flexible and easier operation, higher production yield, and ability to eliminate expensive solvents, although, not eliminating the use of solvents. New mathematical models of the PTC system, which includes physical and chemical equilibrium......Phase-transfer catalyst (PTC) systems contain two immiscible liquid phases with a heterogeneous PTC transferring active ion from one phase to the other for converting the reactant to the desired product, and in the process generating the inactive ion. This type of reacting systems is receiving......, reaction mechanism and unit operation has been developed. In the developed model, the PTC system is divided into four sub-systems of aqueous-organic solvent partition, inorganic salt in aqueous phase, PTC in aqueous phase, and PTC in aqueous phase. Each subsystem requires an appropriate thermodynamic model...

  7. A possible four-phase coexistence in a single-component system

    Science.gov (United States)

    Akahane, Kenji; Russo, John; Tanaka, Hajime

    2016-08-01

    For different phases to coexist in equilibrium at constant temperature T and pressure P, the condition of equal chemical potential μ must be satisfied. This condition dictates that, for a single-component system, the maximum number of phases that can coexist is three. Historically this is known as the Gibbs phase rule, and is one of the oldest and venerable rules of thermodynamics. Here we make use of the fact that, by varying model parameters, the Gibbs phase rule can be generalized so that four phases can coexist even in single-component systems. To systematically search for the quadruple point, we use a monoatomic system interacting with a Stillinger-Weber potential with variable tetrahedrality. Our study indicates that the quadruple point provides flexibility in controlling multiple equilibrium phases and may be realized in systems with tunable interactions, which are nowadays feasible in several soft matter systems such as patchy colloids.

  8. Recent Advances on Neuromorphic Systems Using Phase-Change Materials

    Science.gov (United States)

    Wang, Lei; Lu, Shu-Ren; Wen, Jing

    2017-05-01

    Realization of brain-like computer has always been human's ultimate dream. Today, the possibility of having this dream come true has been significantly boosted due to the advent of several emerging non-volatile memory devices. Within these innovative technologies, phase-change memory device has been commonly regarded as the most promising candidate to imitate the biological brain, owing to its excellent scalability, fast switching speed, and low energy consumption. In this context, a detailed review concerning the physical principles of the neuromorphic circuit using phase-change materials as well as a comprehensive introduction of the currently available phase-change neuromorphic prototypes becomes imperative for scientists to continuously progress the technology of artificial neural networks. In this paper, we first present the biological mechanism of human brain, followed by a brief discussion about physical properties of phase-change materials that recently receive a widespread application on non-volatile memory field. We then survey recent research on different types of neuromorphic circuits using phase-change materials in terms of their respective geometrical architecture and physical schemes to reproduce the biological events of human brain, in particular for spike-time-dependent plasticity. The relevant virtues and limitations of these devices are also evaluated. Finally, the future prospect of the neuromorphic circuit based on phase-change technologies is envisioned.

  9. Predictability during active break phases of Indian summer monsoon in an ensemble prediction system using climate forecast system

    Science.gov (United States)

    Abhilash, S.; Sahai, A. K.; Pattnaik, S.; De, S.

    2013-08-01

    This study examines the phase dependant temporal and spatial error evolution and prediction of active break spells of Indian summer monsoon rainfall in an ensemble prediction system (EPS) on a pentad time scale using climate forecast system (CFS). The EPS system shows systematic wet bias (overestimation) over west coast over the Arabian Sea and Myanmar coast and dry bias (underestimation) over Indian land mass even at pentad 1 lead and these biases consistently increase up to 4 pentad lead and saturate thereafter. Irrespective of the phases of the monsoon, the lower bound of predictability is 2 pentads, while upper bound of predictability for initial conditions starting from active phase saturates at 3 pentads and for break and transition phases predictability error saturates at a later stage at about 5 pentad. Initial conditions started from transition phase shows higher potential predictability followed by break phase and then active phase.

  10. Benchmarking of grid fault modes in single-phase grid-connected photovoltaic systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2012-01-01

    Pushed by the booming installations of single-phase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of low voltage ride-through (LVRT) and the grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant detection and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  11. Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y-Ba-Co-O system

    OpenAIRE

    A.S. Urusova; Cherepanov, V. A.; Aksenova, T. V.; Gavrilova, L. Y.; Kiselev, E. A.

    2013-01-01

    The phase equilibria in the Y-Ba-Co-O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y-Ba-Co-O system at 1373 K in air were: YBaCo2O5+δ, YBaCo4O 7 and BaCo1-yYyO3-δ (0.09≤y≤0.42). It was shown that YBaCo2O5+δ possesses tetragonal structure with the 3ap×3a p×2ap superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo2O 5+δ in the temperature range from 298 K up to 1073 K under Po2=0.21 atm has not shown any phase tra...

  12. Phase Transformations and Phase Equilibria in the Fe-N System at Temperatures below 573 K

    DEFF Research Database (Denmark)

    Malinov, S.; Böttger, A.J.; Mittemeijer, E.J.;

    2001-01-01

    The phase transformations of homogeneous Fe-N alloys of nitrogen contents from 10 to 26 at. pct were investigated by means of X-ray diffraction analysis upon aging in the temperature range from 373 to 473 K. It was found that precipitation of alpha double prime-Fe16N2 below 443 K does not only oc...

  13. An Efficient Phase-Locked Loop for Distorted Three-Phase Systems

    Directory of Open Access Journals (Sweden)

    Yijia Cao

    2017-02-01

    Full Text Available This paper proposed an efficient phase-locked loop (PLL that features zero steady-state error of phase and frequency under voltage sag, phase jump, harmonics, DC offsets and step-and ramp-changed frequency. The PLL includes the sliding Goertzel discrete Fourier transform (SGDFT filter-based fundamental positive sequence component separator (FPSCS, the synchronousreference-frame PLL (SRF-PLL and the secondary control path (SCP. In order to obtain an accurate fundamental positive sequence component, SGDFT filter is introduced as it features better filtering ability at the frequencies that are integer times of fundamental frequency. Meanwhile, the second order Lagrange-interpolation method is employed to approximate the actual sampling number including both integer and fractional parts as grid frequency may deviate from the rated value. Moreover, an improved SCP with single-step comparison filtering algorithm is employed as it updates reference angular frequency according to the FPSC, which promises a zero steady-state error of phase and improves the frequency tracking speed. In this paper, the mathematical model of the proposed PLL is constructed, its stability is analyzed. Also, design procedure of the control parameters is presented. The effectiveness of the proposed PLL is confirmed by experimental results and comparison with advanced pre-filtering PLLs.

  14. Optical transfer function analysis of circular-pupil wavefront coding systems with separable phase masks

    Institute of Scientific and Technical Information of China (English)

    Zhao Ting-Yu; Liu Qin-Xiao; Yu Fei-Hong

    2012-01-01

    This paper proposes a simple method to achieve the optical transfer function of a circular pupil wavefront coding system with a separable phase mask in Cartesian coordinates.Based on the stationary phase method,the optical transfer function of the circular pupil system can be easily obtained from the optical transfer function of the rectangular pupil system by modifying the cut-off frequency and the on-axial modulation transfer function.Finally,a system with a cubic phase mask is used as an example to illustrate the way to achieve the optical transfer function of the circular pupil system from the rectangular pupil system.

  15. DSC study of phase transitions of cephalin pseudo-binary systems in excess water

    Institute of Scientific and Technical Information of China (English)

    王邦宁; 谈夫

    1999-01-01

    The gel-liquid crystal phase transitions of the pseudo-binary systems of cephalins DMPE and DHPE in excess water were studied by differential scanning calorimetry. The phase diagram of the pseudo-binary systems has been given. The experiments showed that the partial phase separation in gel phase might occur at least at the mole fractions of DHPE below 0.1. The analysis by the model of ideal solution showed that both the cephalins were non-ideally miscible both in the gel phases and in the liquid crystal phases. The analysis by the model of regular solution showed that all the non-ideality parameters in the gel phases were larger than those in the liquid crystal phases at the same temperature. All the non-ideality parameters were not constant, but rather dependent on temperature.

  16. System-level simulation of a noisy phase-locked loop

    OpenAIRE

    Herzel, Frank; Piz, Maxim

    2005-01-01

    This paper presents a compact model of a noisy phase-locked loop (PLL) for inclusion in a time-domain system simulation. The phase noise of the reference is modeled as a Wiener process, and the phase noise contribution of the voltage-controlled oscillator (VCO) is described as an Ornstein-Uhlenbeck process. The model is applied to phase error modeling for a 60 GHz OFDM system including correction of the common phase error. A close agreement is observed between the time-domain simulation and a...

  17. Pixel-wise absolute phase unwrapping using geometric constraints of structured light system.

    Science.gov (United States)

    An, Yatong; Hyun, Jae-Sang; Zhang, Song

    2016-08-08

    This paper presents a method to unwrap phase pixel by pixel by solely using geometric constraints of the structured light system without requiring additional image acquisition or another camera. Specifically, an artificial absolute phase map, Φmin, at a given virtual depth plane z = zmin, is created from geometric constraints of the calibrated structured light system; the wrapped phase is pixel-by-pixel unwrapped by referring to Φmin. Since Φmin is defined in the projector space, the unwrapped phase obtained from this method is absolute for each pixel. Experimental results demonstrate the success of this proposed novel absolute phase unwrapping method.

  18. MIDAS, prototype Multivariate Interactive Digital Analysis System, Phase 1. Volume 2: Diagnostic system

    Science.gov (United States)

    Kriegler, F. J.; Christenson, D.; Gordon, M.; Kistler, R.; Lampert, S.; Marshall, R.; Mclaughlin, R.

    1974-01-01

    The MIDAS System is a third-generation, fast, multispectral recognition system able to keep pace with the large quantity and high rates of data acquisition from present and projected sensors. A principal objective of the MIDAS Program is to provide a system well interfaced with the human operator and thus to obtain large overall reductions in turn-around time and significant gains in throughout. The hardware and software generated in Phase I of the over-all program are described. The system contains a mini-computer to control the various high-speed processing elements in the data path and a classifier which implements an all-digital prototype multivariate-Gaussian maximum likelihood decision algorithm operating 2 x 105 pixels/sec. Sufficient hardware was developed to perform signature extraction from computer-compatible tapes, compute classifier coefficients, control the classifier operation, and diagnose operation. Diagnostic programs used to test MIDAS' operations are presented.

  19. Transition from phase to generalized synchronization in time-delay systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M; Kurths, J

    2008-06-01

    The notion of phase synchronization in time-delay systems, exhibiting highly non-phase-coherent attractors, has not been realized yet even though it has been well studied in chaotic dynamical systems without delay. We report the identification of phase synchronization in coupled nonidentical piecewise linear and in coupled Mackey-Glass time-delay systems with highly non-phase-coherent regimes. We show that there is a transition from nonsynchronized behavior to phase and then to generalized synchronization as a function of coupling strength. We have introduced a transformation to capture the phase of the non-phase-coherent attractors, which works equally well for both the time-delay systems. The instantaneous phases of the above coupled systems calculated from the transformed attractors satisfy both the phase and mean frequency locking conditions. These transitions are also characterized in terms of recurrence-based indices, namely generalized autocorrelation function P(t), correlation of probability of recurrence, joint probability of recurrence, and similarity of probability of recurrence. We have quantified the different synchronization regimes in terms of these indices. The existence of phase synchronization is also characterized by typical transitions in the Lyapunov exponents of the coupled time-delay systems.

  20. Phase-locked loops. [in analog and digital circuits communication system

    Science.gov (United States)

    Gupta, S. C.

    1975-01-01

    An attempt to systematically outline the work done in the area of phase-locked loops which are now used in modern communication system design is presented. The analog phase-locked loops are well documented in several books but discrete, analog-digital, and digital phase-locked loop work is scattered. Apart from discussing the various analysis, design, and application aspects of phase-locked loops, a number of references are given in the bibliography.

  1. Kinetics of phase separation in systems exhibiting simple coacervation

    Science.gov (United States)

    Gupta, Amarnath; Bohidar, H. B.

    2005-07-01

    The kinetics of phase separation of a homogeneous polyelectrolytic solution into a dense polymer-rich coacervate and the dilute supernatant phase is discussed through statistical thermodynamics. It has been shown that the coacervate phase is associated with higher internal pressure, consequently giving rise to syneresis. Physical conditions for phase separations has been deduced explicitly which reveals that σ2/I⩾ constant (where σ is polyelectrolyte charge density and I is solution ionic strength), consistent with experimental observations. In the lattice model, r is the number of sites occupied by the polymer having a volume critical fraction φ2c , it was found that phase separation would ensue when σ3r⩾(64/9α2)[φ2c/(1-φ2c)2] , which reduces to (σ3r/φ2c)⩾(64/9α2)≈0.45 at 20 °C for φ2c≪1 . The separation kinetics mimics a spinodal decomposition process. Rate of release of supernatant due to syneresis was found to be independent of the initial coacervate mass. Syneresis results are discussed in the context of temporal evolution of self-organization in polymer melts through Avrami model.

  2. CHROMIUM EXTRACTION BY MICROEMULSIONS IN TWO- AND THREE-PHASE SYSTEMS

    Directory of Open Access Journals (Sweden)

    K. R. O. Melo

    2015-12-01

    Full Text Available Abstract Microemulsion systems were used to remove chromium from an aqueous solution obtained from acid digestion of tannery sludge. The systems were composed by: coconut oil soap as surfactant, 1-butanol as cosurfactant, kerosene as the oil phase, and chromium solution as the aqueous phase. Two- and three-phase microemulsion extraction methods were investigated in the experiments. Viscosity, effective diameter of the droplets, and extraction and re-extraction efficiencies were evaluated for each system. Two- and three-phase systems showed small variations in droplet diameter, which can be attributed to the formation of micellar structures. Chromium recovery efficiencies for the studied systems were over 96%. The re-extraction step showed that the stripping solution used can release more than 96% of the chromium from the microemulsion phase. Experimental results confirm that chromium can be recovered efficiently using microemulsion systems.

  3. Phase behavior and interfacial tension studies of surfactant systems

    Energy Technology Data Exchange (ETDEWEB)

    Franses, E.I.

    1979-01-01

    Parallel studies of isomerically pure sodium P(1-heptylnonyl) benzene sulfoante, Texas No. 1, its mixture with sodium dodecyl sulfate (SDS), and the petroleum sulfonate TRS 10-80 were made. Phase behavior in water, in decane, and in water-decane mixtures was studied by spectroturbidimetry, polarizing light microscopy, ultracentrifugation, ultrafiltration, densitometry, conductimetry, low-frequency, 0.2 to 20 kHz, dielectric relaxation, isopiestic vapor pressure, and nuclear magnetic resonance spectroscopy. It was deduced that ultralow tensions (less than 0.01 dyn/cm) arise from the dispersed microcrystallites which form a third, usually liquid crystalline, phase at the decane-brine interfacial region. It appears that neither molecular adsorption from solution for micelles have anything to do with ultralow tensions, which appear to be sensitive to the third phase microstructure. The implications of these results for the mechanism of ultralow tensions in surfactant flooding processes for enhanced petroleum recovery are discussed.

  4. A simplification of the fractional Hartley transform applied to image security system in phase

    Science.gov (United States)

    Jimenez, Carlos J.; Vilardy, Juan M.; Perez, Ronal

    2017-01-01

    In this work we develop a new encryption system for encoded image in phase using the fractional Hartley transform (FrHT), truncation operations and random phase masks (RPMs). We introduce a simplification of the FrHT with the purpose of computing this transform in an efficient and fast way. The security of the encryption system is increased by using nonlinear operations, such as the phase encoding and the truncation operations. The image to encrypt (original image) is encoded in phase and the truncation operations applied in the encryption-decryption system are the amplitude and phase truncations. The encrypted image is protected by six keys, which are the two fractional orders of the FrHTs, the two RPMs and the two pseudorandom code images generated by the amplitude and phase truncation operations. All these keys have to be correct for a proper recovery of the original image in the decryption system. We present digital results that confirm our approach.

  5. System Qualities Ontology, Tradespace and Affordability (SQOTA) Project: Phase 5

    Science.gov (United States)

    2017-04-30

    point- solution, acquisition-oriented approaches; and toward concurrent, portfolio and enterprise- oriented, hardware-software-human engineered...extensions for the effects of system reusability, reuse, requirements volatility , and systems of systems integration, and developing an initial quantitative

  6. Camomile autofermentation in polyethylene glycol/dextran two-phase system

    Directory of Open Access Journals (Sweden)

    Đaković Sanja D.

    2008-01-01

    Full Text Available The objective of this study was the investigation of the extractive bioconversion of apigenin-7-O-β-glucoside in camomile ligulate flowers into apigenin by autofermentation in polyethylene glycol 6000/dextran 200000 two-phase system. In 22.5% polyethylene glycol/14% dextran aqueous two-phase system the obtained yield of apigenin in the top phase was 96.5%. In the presence of plant material that partiotioned to the interphase, the yield of apigenin in the top phase was 3.5 times higher in comparison to the model system.

  7. Application of New Electrolyte Model to Phase Transfer Catalyst (PTC) Systems

    DEFF Research Database (Denmark)

    2015-01-01

    Abstract Phase transfer catalyst (PTC) is used to transfer the desirable active form of an anion from the aqueous phase to organic phase where the reaction occurs. One of major challenges for process design of the PTC system is to establish a reliable thermodynamic model capable of describing phase...... in PTC systems, thereby, extending the application range of the PTC-system model. The solubility of PTC in organic solvents, which is a key factor for strategy of PTC and solvent selection, has been calculated using the e-NRTL-SAC model....

  8. PAPR Reduction in All-optical OFDM Systems Based on Phase Pre-emphasis

    Energy Technology Data Exchange (ETDEWEB)

    He Zhou; Li, Wei; Shao Jing; Liang Xiaojun; Huang Dexiu [Wuhan National Lab for Optoelectronics, Department of Optoelectronics Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Tao Zhiyong [State Key Laboratory of Optical Communication Technologies and Networks, Wuhan Research Institute of Posts and Telecommunications, Wuhan 430074 (China); Deng Zhuanhua, E-mail: hezhou@wri.com.cn, E-mail: weilee@mail.hust.edu.cn [School of Computer Science and Technology, Hubei University of Economics, Wuhan 430205 (China)

    2011-02-01

    This paper investigates the peak-to-average power ratio (PAPR) theory in all-optical orthogonal frequency division multiplexing (OFDM) optical fibre communication systems. We find out that phase pre-emphasis could effectively reduce PAPR in all-optical OFDM communication systems which employ intensity modulation-direct detection (IM-DD) method. An equation is developed and proposed to calculate suitable phasing values for pre-emphasis. Furthermore, we find out that phase pre-emphasis cannot reduce PAPR effectively in all-optical OFDM systems that employ Phase Shift Keying (PSK) or Quadracture Amplitude Modulation (QAM) method.

  9. Bell's inequality for systems with quadrature phase coherence

    Science.gov (United States)

    Tan, S. M.; Holland, M. J.; Walls, D. F.

    1990-07-01

    We show that a violation of Bell's inequalities by quadrature phase measurements is not due to the interference of the two photons in a photon pair state. Rather the violation predicted by Grangier et al. for a parametric down-converter is due to the interference of the photon pair state with the vacuum. We propose new sources which violate the quadrature phase Bell's inequalities, including one which employs squeezed light and another which demonstrates the non-local properties of a single photon state.

  10. Distribution of current in nonequilibrium diffusive systems and phase transitions

    Science.gov (United States)

    Bodineau, T.; Derrida, B.

    2005-12-01

    We consider diffusive lattice gases on a ring and analyze the stability of their density profiles conditionally to a current deviation. Depending on the current, one observes a phase transition between a regime where the density remains constant and another regime where the density becomes time dependent. Numerical data confirm this phase transition. This time dependent profile persists in the large drift limit and allows one to understand on physical grounds the results obtained earlier for the totally asymmetric exclusion process on a ring.

  11. Joint carrier phase and symbol timing recovery for PAM systems

    Science.gov (United States)

    Meyers, M. H.; Franks, L. E.

    1980-08-01

    The theory of maximum likelihood (ML) estimation as applied to PAM timing and phase recovery is considered. Data-aided (DA) and nondata-aided (NDA) strategies used for the joint estimation of both phase and timing parameters are evaluated on the basis of their error variances. The comparisons of the effects of excess bandwidth, different modulation schemes, DA versus NDA recovery, and joint estimation versus estimation of only one parameter are presented. A practical implementation of a proposed ML estimator, named a pseudo-maximum likelihood (PML) estimator, exhibits a noise-independent, data dependent jitter that dominates in many cases of practical interest.

  12. Deep Learning the Quantum Phase Transitions in Random Two-Dimensional Electron Systems

    Science.gov (United States)

    Ohtsuki, Tomoki; Ohtsuki, Tomi

    2016-12-01

    Random electron systems show rich phases such as Anderson insulator, diffusive metal, quantum Hall and quantum anomalous Hall insulators, Weyl semimetal, as well as strong/weak topological insulators. Eigenfunctions of each matter phase have specific features, but owing to the random nature of systems, determining the matter phase from eigenfunctions is difficult. Here, we propose the deep learning algorithm to capture the features of eigenfunctions. Localization-delocalization transition, as well as disordered Chern insulator-Anderson insulator transition, is discussed.

  13. Analysis of Phased-Mission System Reliability and Importance with Imperfect Coverage

    Institute of Scientific and Technical Information of China (English)

    CHEN Guang-yu; HUANG Xi-zi; TANG Xiao-wo

    2005-01-01

    Accounting for static phased-mission systems (PMS) and imperfect coverage (IPC), generalized and integrated algorithm (GPMS-CPR) implemented a synthesis of several approaches into a single methodology whose advantages were in the low computational complexity, broad applicability, and easy implementation. The approach is extended into analysis of each phase in the whole mission. Based on Fussell-Vesely importance measure, a simple and efficient importance measure is presented to analyze component's importance of phased-mission systems considering imperfect coverage.

  14. Thermodynamic studies of induced antiferroelectric phases in chiral and racemic systems

    Science.gov (United States)

    Filipowicz, M.; Kula, P.; Czuprynski, Krzysztof

    2004-09-01

    Bi- and multicomponent mixtures consisted of two groups of synclinic chiral esters: first one with a partially fluorinated terminal chain and the second one with hydrogenated terminal chain have been used for investigations. For some systems the induction of the anticlinic smectic CA* phase was observed. Enthalpies of the phase transitions for the systems with induced smectic CA phase upon compositions and specific heat were measured by DSC method.

  15. A Data Management System for Multi-Phase Case-Control Studies

    OpenAIRE

    Gibeau, Joanne M.; Steinfeldt, Lois C; Stine, Mark J.; Tullis, Katherine V.; Lynch, H. Keith

    1983-01-01

    The design of a computerized system for the management of data in multi-phase epidemiologic case-control studies is described. Typical study phases include case-control selection, abstracting of data from medical records, and interview of study subjects or next of kin. In consultation with project personnel, requirements for the system were established: integration of data from all study phases into one data base, accurate follow-up of subjects through the study, sophisticated data editing ca...

  16. Prostaglandin H synthase kinetics in the two-phase aqueous-micellar system.

    Science.gov (United States)

    Ponomareva, Olga A; Trushkin, Nikita A; Filimonov, Ivan S; Krivoshey, Alexandr V; Barkhatov, Vladimir I; Mitrofanov, Sergey I; Vrzheshch, Petr V

    2016-09-01

    Reaction mixture for PGHS (prostaglandin-H-synthase) is a two-phase system including micellar hydrophobic phase and hydrophilic aqueous phase. Reagents added to the mixture are distributed between phases, thus concentrations of reagents dissolved in phases can differ significantly from their overall contents. Using dynamic light scattering we found that the hydrophobic phase produced by tween-20 consists of micelles, which radius (4-5nm) does not depend on either tween-20 overall content (0.1%-1% v/v) or arachidonic acid (AA) addition (10-1000μM) or PGHS addition (1μM). Tween-20 overall content changing from 0.1% to 2% v/v dramatically affected COX kinetic, but accounting AA distribution between phases allowed us to estimate "true" parameters, independent of the tween-20 overall content and the concentration of another substrate: KM(Ox) equals 9.8μM O2 in the aqueous phase or 0.0074bar in the gaseous phase, KM(AA) equals 5400μM AA in the phase of tween-20 micelles and 5400/PμM AA in the aqueous phase (P is the distribution ratio for the AA between the aqueous phase and the hydrophobic phase (P≫1000)). This approach allowed to evaluate PS, the distribution ratio for the AA between the hydrophobic phase and the PGHS active center (PS ~310). This coefficient indicates the AA selectivity toward the cyclooxygenase active center.

  17. Phase equilibria in the In–Sb–Bi system at 300 ºC

    Directory of Open Access Journals (Sweden)

    DUSKO MINIC

    2006-07-01

    Full Text Available Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In–Sb, Bi–Sb and In–Bi, were used fort the prediction of phase equilibria in the ternary system In–Sb–Bi at 300 ºC. The predicted equilibria were compared with the results of SEM–EDX analysis.

  18. Study on phase equilibrium of Np-Pu-U-O system

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akio; Yamashita, Toshiyuki; Shirasu, Noriko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

    1999-10-01

    Uranium and neptunium oxide system was studied using high-temperature X-ray diffraction method, thermogravimetric analysis and electric conductivity measurement to deduce the phase diagrams of the system, to clarify defect structure in the solid solution, to determine the activation energy and to calculate the specific heat content. Characteristics of the U-Np-O phase equilibrium were investigated. (S. Ohno)

  19. Embedding Game-Based Problem-Solving Phase into Problem-Posing System for Mathematics Learning

    Science.gov (United States)

    Chang, Kuo-En; Wu, Lin-Jung; Weng, Sheng-En; Sung, Yao-Ting

    2012-01-01

    A problem-posing system is developed with four phases including posing problem, planning, solving problem, and looking back, in which the "solving problem" phase is implemented by game-scenarios. The system supports elementary students in the process of problem-posing, allowing them to fully engage in mathematical activities. In total, 92 fifth…

  20. Centralised, decentralised or hybrid sanitation systems? Economic evaluation under urban development uncertainty and phased expansion

    NARCIS (Netherlands)

    Roefs, Ivar; Meulman, Brendo; Vreeburg, Jan H.G.; Spiller, Marc

    2017-01-01

    Sanitation systems are built to be robust, that is, they are dimensioned to cope with population growth and other variability that occurs throughout their lifetime. It was recently shown that building sanitation systems in phases is more cost effective than one robust design. This phasing can tak

  1. Phase Behaviour and Structural Aspects of Ternary Clathrate Hydrate Systems. The Role of Additives

    NARCIS (Netherlands)

    Mooijer-Van den Heuvel, M.M.

    2004-01-01

    In this study an experimental and modelling approach is applied to obtain fundamental insight into the phase behaviour of ternary systems, in which clathrate hydrates are formed. Proper interpretation of the phase behaviour requires knowledge on the clathrate hydrate structure in these systems, whic

  2. Common world model for unmanned systems: Phase 2

    Science.gov (United States)

    Dean, Robert M. S.; Oh, Jean; Vinokurov, Jerry

    2014-06-01

    The Robotics Collaborative Technology Alliance (RCTA) seeks to provide adaptive robot capabilities which move beyond traditional metric algorithms to include cognitive capabilities. Key to this effort is the Common World Model, which moves beyond the state-of-the-art by representing the world using semantic and symbolic as well as metric information. It joins these layers of information to define objects in the world. These objects may be reasoned upon jointly using traditional geometric, symbolic cognitive algorithms and new computational nodes formed by the combination of these disciplines to address Symbol Grounding and Uncertainty. The Common World Model must understand how these objects relate to each other. It includes the concept of Self-Information about the robot. By encoding current capability, component status, task execution state, and their histories we track information which enables the robot to reason and adapt its performance using Meta-Cognition and Machine Learning principles. The world model also includes models of how entities in the environment behave which enable prediction of future world states. To manage complexity, we have adopted a phased implementation approach. Phase 1, published in these proceedings in 2013 [1], presented the approach for linking metric with symbolic information and interfaces for traditional planners and cognitive reasoning. Here we discuss the design of "Phase 2" of this world model, which extends the Phase 1 design API, data structures, and reviews the use of the Common World Model as part of a semantic navigation use case.

  3. A phase-locked laser system based on modulation technique for atom interferometry

    CERN Document Server

    Li, Wei; Song, Ningfang; Xu, Xiaobin; Lu, Xiangxiang

    2016-01-01

    We demonstrate a Raman laser system based on phase modulation technology and phase feedback control. The two laser beams with frequency difference of 6.835 GHz are modulated using electro-optic and acousto-optic modulators, respectively. Parasitic frequency components produced by the electro-optic modulator are filtered using a Fabry-Perot Etalon. A straightforward phase feedback system restrains the phase noise induced by environmental perturbations. The phase noise of the laser system stays below -125 rad2/Hz at frequency offset higher than 500 kHz. Overall phase noise of the laser system is evaluated by calculating the contribution of the phase noise to the sensitivity limit of a gravimeter. The results reveal that the sensitivity limited by the phase noise of our laser system is lower than that of a state-of-art optical phase-lock loop scheme when a gravimeter operates at short pulse duration, which makes the laser system a promising option for our future application of atom interferometer.

  4. A phase-locked laser system based on double direct modulation technique for atom interferometry

    Science.gov (United States)

    Li, Wei; Pan, Xiong; Song, Ningfang; Xu, Xiaobin; Lu, Xiangxiang

    2017-02-01

    We demonstrate a laser system based on phase modulation technology and phase feedback control. The two laser beams with frequency difference of 6.835 GHz are modulated using electro-optic and acousto-optic modulators, respectively. Parasitic frequency components produced by the electro-optic modulator are filtered using a Fabry-Perot Etalon. A straightforward phase feedback system restrains the phase noise induced by environmental perturbations. The phase noise of the laser system stays below -125 rad2/Hz at frequency offset higher than 500 kHz. Overall phase noise of the laser system is evaluated by calculating the contribution of the phase noise to the sensitivity limit of a gravimeter. The results reveal that the sensitivity limited by the phase noise of our laser system is lower than that of a state-of-the-art optical phase-lock loop scheme when a gravimeter operates at short pulse duration, which makes the laser system a promising option for our future application of atom interferometer.

  5. Phase equilibria in fluid mixtures at high pressures - The He-CH4 system.

    Science.gov (United States)

    Streett, W. B.; Erickson, A. L.; Hill, J. L. E.

    1972-01-01

    An experimental study of phase equilibria in the He-CH4 system has been carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.-

  6. Synchronization in single-phase grid-connected photovoltaic systems under grid faults

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2012-01-01

    The highly increasing penetration of single-phase photovoltaic (PV) systems pushes the grid requirements related to the integration of PV power systems to be updated. These upcoming regulations are expected to direct the grid-connected renewable generators to support the grid operation...... and stability both under grid faulty conditions and under normal operations. Grid synchronization techniques play an important role in the control of single-phase systems in order to fulfill these demands. Thus, it is necessary to evaluate the behaviors of grid synchronization methods in single phase systems...... under grid faults. The focus of this paper is put on the benchmarking of synchronization techniques, mainly about phase locked loop (PLL) based methods, in single-phase PV power systems operating under grid faults. Some faulty mode cases are studied at the end of this paper in order to compare...

  7. Ageing in a system of polydisperse goethite boardlike particles showing rich phase behaviour.

    Science.gov (United States)

    Leferink op Reinink, A B G M; van den Pol, E; Byelov, D V; Petukhov, A V; Vroege, G J

    2012-11-21

    Using microradian x-ray scattering and polarized light microscopy the rich liquid crystalline phase behaviour of a polydisperse system of chromium-modified goethite particles has been studied for five years. We observe that the particles stay highly mobile over years and the rich phase behaviour keeps developing in novel and even surprising ways. While in many other colloidal systems particle size polydispersity suppresses the formation of ordered phases, goethite particles form multiple coexisting ordered phases. The particle polydispersity problem is then solved by particle exchange between coexisting phases. One usually expects that a less ordered phase (e.g., nematic) is formed first while crystallization of the smectic and columnar crystals might take a longer time. For goethite particles we find the opposite, i.e. the nematic phase grows over years at the expense of a better ordered smectic phase. Moreover, SAXS patterns revealed peak splitting for both the smectic and the columnar phase, meaning that the system displays fractionated crystallization. We further discovered that the centred rectangular columnar phase spontaneously forms out of the simple rectangular columnar phase. The reverse transition is observed as well. We explain the ease of these martensitic transitions by showing how slight rotation and translation of the particles triggers the transition.

  8. Phase Diagrams of the Aqueous Two-Phase Systems of Poly(ethylene glycol/Sodium Polyacrylate/Salts

    Directory of Open Access Journals (Sweden)

    Adalberto Pessoa Junior

    2011-03-01

    Full Text Available Aqueous two-phase systems consisting of polyethylene glycol (PEG, sodium polyacrylate (NaPAA, and a salt have been studied. The effects of the polymer size, salt type (NaCl, Na2SO4, sodium adipate and sodium azelate and salt concentrations on the position of the binodal curve were investigated. The investigated PEG molecules had a molar mass of 2,000 to 8,000 g/mol, while that of NaPAA was 8,000 g/mol. Experimental phase diagrams, and tie lines and calculated phase diagrams, based on Flory-Huggins theory of polymer solutions are presented. Due to strong enthalpic and entropic balancing forces, the hydrophobicity of the added salt has a strong influence on the position of the binodal, which could be reproduced by model calculations.

  9. Heat transfer studies in a spiral plate heat exchanger for water: palm oil two phase system

    Directory of Open Access Journals (Sweden)

    S. Ramachandran

    2008-09-01

    Full Text Available Experimental studies were conducted in a spiral plate heat exchanger with hot water as the service fluid and the two-phase system of water – palm oil in different mass fractions and flow rates as the cold process fluid. The two phase heat transfer coefficients were correlated with Reynolds numbers (Re in the form h = a Re m, adopting an approach available in literature for two phase fluid flow. The heat transfer coefficients were also related to the mass fraction of palm oil for identical Reynolds numbers. The two-phase multiplier (ratio of the heat transfer coefficient of the two phase fluid and that of the single phase fluid was correlated with the Lockhart Martinelli parameter in a polynomial form. This enables prediction of the two-phase coefficients using single-phase data. The predicted coefficients showed a spread of ± 10 % in the laminar range.

  10. GPS-Like Phasing Control of the Space Solar Power System Transmission Array

    Science.gov (United States)

    Psiaki, Mark L.

    2003-01-01

    The problem of phasing of the Space Solar Power System's transmission array has been addressed by developing a GPS-like radio navigation system. The goal of this system is to provide power transmission phasing control for each node of the array that causes the power signals to add constructively at the ground reception station. The phasing control system operates in a distributed manner, which makes it practical to implement. A leader node and two radio navigation beacons are used to control the power transmission phasing of multiple follower nodes. The necessary one-way communications to the follower nodes are implemented using the RF beacon signals. The phasing control system uses differential carrier phase relative navigation/timing techniques. A special feature of the system is an integer ambiguity resolution procedure that periodically resolves carrier phase cycle count ambiguities via encoding of pseudo-random number codes on the power transmission signals. The system is capable of achieving phasing accuracies on the order of 3 mm down to 0.4 mm depending on whether the radio navigation beacons operate in the L or C bands.

  11. Benchmarking of Grid Fault Modes in Single-Phase Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede; Zou, Zhixiang

    2013-01-01

    Pushed by the booming installations of singlephase photovoltaic (PV) systems, the grid demands regarding the integration of PV systems are expected to be modified. Hence, the future PV systems should become more active with functionalities of Low Voltage Ride-Through (LVRT) and grid support...... phase systems under grid faults. The intent of this paper is to present a benchmarking of grid fault modes that might come in future single-phase PV systems. In order to map future challenges, the relevant synchronization and control strategies are discussed. Some faulty modes are studied experimentally...... and provided at the end of this paper. It is concluded that there are extensive control possibilities in single-phase PV systems under grid faults. The Second Order General Integral based PLL technique might be the most promising candidate for future single-phase PV systems because of its fast adaptive...

  12. Fractional order phase shaper design with Bode's integral for iso-damped control system.

    Science.gov (United States)

    Saha, Suman; Das, Saptarshi; Ghosh, Ratna; Goswami, Bhaswati; Balasubramanian, R; Chandra, A K; Das, Shantanu; Gupta, Amitava

    2010-04-01

    The phase curve of an open loop system is flat in nature if the derivative of its phase with respect to frequency is zero. With a flat-phase curve, the corresponding closed loop system exhibits an iso-damped property i.e. maintains constant overshoot with the change of gain. This implies enhanced parametric robustness e.g. to variation in system gain. In the recent past, fractional order (FO) phase shapers have been proposed by contemporary researchers to achieve enhanced parametric robustness. In this paper, a simple methodology is proposed to design an appropriate FO phase shaper to achieve phase flattening in a control loop, comprising a plant controlled by a classical Proportional Integral Derivative (PID) controller. The methodology is demonstrated with MATLAB simulation of representative plants and accompanying PID controllers.

  13. Second Generation PFBC Systems R&D - Phase 2 and Phase 3

    Energy Technology Data Exchange (ETDEWEB)

    A. Robertson

    1999-10-25

    When DOE funds were exhausted in March 1995, all Phase 2 activities were placed on hold. In February 1996 a detailed cost estimate was submitted to the DOE for completing the two remaining Phase 2 Multi Annular Swirl Burner (MASB) topping combustor test campaigns; in August 1996 release was received from FETC to proceed with the two campaigns to: (1) test the MASB at proposed demonstration plant full to minimum load operating conditions; (2) identify the lower oxygen limit of the MASB; (3) demonstrate natural gas to carbonizer fuel gas switching; and (4) demonstrate operation with ''low temperature'' compressor discharge air rather than high temperature ({approx} 1600 F) vitiated air. The 18 in. MASB was last tested at the University of Tennessee Space Institute (UTSI) in a high-oxygen configuration and must be redesigned/modified for low oxygen operation. A second-generation PFB combustion plant incorporating an MASB based topping combustor has been proposed for construction at the City of Lakeland's McIntosh Power Plant under the U.S. DOE Clean Coal V Demonstration Plant Program. This plant will require the MASB to operate at oxygen levels that are lower than those previously tested. Preliminary calculations aimed at defining the operating envelope of the demonstration plant MASB have been completed. The previous MASB tests have been performed at UTSI in a facility constructed to support the development of MHD power generation. Because of a loss of MHD funding, the UTSI facility closed October 1998. On February 2, 1999, Siemens Westinghouse proposed a 12-week study that would identify the cost of modifying the MASB for Lakeland low oxygen operation conditions and conducting tests 3 and 4 above at the Arnold Engineering Development Center (AEDC). On February 22, 1999, Siemens Westinghouse was given release to proceed with this study and results/recommendations were received on April 22, 1999. Siemens Westinghouse recommended a two-phase

  14. ENERGY LOSS REDUCTION IN SMART GRID UTILITIES FOR ACCOUNT OF TRANSITION FROM SINGLE-PHASE TO THREE-PHASE POWER DISTRIBUTION SYSTEMS

    Directory of Open Access Journals (Sweden)

    G.G. Zhemerov

    2014-10-01

    Full Text Available Analytical dependences of such efficiency indices as energy loss power and copper consumption under transition from single-phase power distribution systems to three-phase ones are obtained.

  15. TERNARY PHASE EQUILIBRIA IN TRANSITION METAL-BORON-CARBON-SILICON SYSTEMS. PART 4. THERMOCHEMICAL CALCULATIONS, VOLUME 3. COMPUTATIONAL APPROACH TO THE CALCULATION OF TERNARY PHASE DIAGRAMS

    Science.gov (United States)

    The general conditional equations which govern the phase equilibria in three-component systems are presented. Using the general conditional equations...a general method has been developed to precalculate the phase equilibria in three-component systems from first principle using computer technique...The method developed has been applied to several model examples and the system Ta-Hf-C. The phase equilibria in three-component systems calculated

  16. Aqueous Two-Phase Systems formed by Biocompatible and Biodegradable Polysaccharides and Acetonitrile.

    Science.gov (United States)

    de Brito Cardoso, Gustavo; Souza, Isabela Nascimento; Pereira, Matheus M; Freire, Mara G; Soares, Cleide Mara Faria; Lima, Álvaro Silva

    2014-11-05

    In this work, it is shown that novel aqueous two-phase systems can be formed by the combination of acetonitrile and polysaccharides, namely dextran. Several ternary phase diagrams were determined at 25 °C for the systems composed of water + acetonitrile + dextran. The effect of the dextran molecular weight (6,000, 40,000 and 100,000 g.mol(-1)) was ascertained toward their ability to undergo liquid-liquid demixing. An increase in the dextran molecular weight favors the phase separation. Furthermore, the effect of temperature (25, 35 and 45 °C) was evaluated for the system constituted by the dextran of higher molecular weight. Lower temperatures are favorable for phase separation since lower amounts of dextran and acetonitrile are required for the creation of aqueous two-phase systems. In general, acetonitrile is enriched in the top phase while dextran is majorly concentrated in the bottom phase. The applicability of this new type of two-phase systems as liquid-liquid extraction approaches was also evaluated by the study of the partition behavior of a well-known antioxidant - vanillin - and used here as a model biomolecule. The optimized conditions led to an extraction efficiency of vanillin of 95% at the acetonitrile-rich phase.

  17. Stability of phases in (Ba, Gd)MnO3 solid solution system

    Institute of Scientific and Technical Information of China (English)

    Migaku Kobayashi; Hidenori Tamura; Hiromi Nakano; Hirohisa Satoh; Naoki Kamegashira

    2008-01-01

    The existing phases in BaxGd1-xMnO3 solid solution system (0≦x≦1) were studied by analyzing the detailed crystal structure of each composition from the results of the Rietveld method using powder X-ray diffraction data. For a small substitution of Ba for Gd (0≦x<0.1), the orthorhombic phase with a perovskite type structure (Pnma space group) was stably formed and this fact was supported by the electron diffraction data. There existed an intermediate phase of Ba0.33Gd0.67MnO3, which was characterized as the tetragonal phase with perovskite structure. The composition range of this phase was narrow and almost line compound. Between the regions of these phases, there existed two-phase region. There was also a two-phase region between the intermediate tetragonal phase and BaMnO3. Measurement of electrical conductivities of these orthorhombic solid solutions and tetragonal phases showed semiconducting behaviors for both phases and the existence of the phase transition at high temperature for the orthorhombic phase. The transition temperature decreased as the Ba content increased.

  18. Isothermal section (500  ℃) of phase diagram of Nd-Al-Si ternary system

    Institute of Scientific and Technical Information of China (English)

    龙志林; 周益春; 庄应烘; 陈荣贞; 刘敬旗

    2001-01-01

    The isothermal section of the phase diagram of the ternary system Nd-Al-Si at 500  ℃ (Nd≤50%, mole fraction) has been constructed on the basis of the data obtained by X-ray diffraction analysis, differential thermal analysis, metallographic examination, chemical analysis and electron micro-probe analysis. The obtained diagram consists of 11 single-phase regions, 21 two-phase regions and 11 three-phase regions. There exist two limit solid solutions. The intermetallic compound NdAl1.5Si0.5 has not been found in this section. No evidence of new phase has been observed in this work.

  19. Quantum phase noise and field correlation in single frequency semiconductor laser systems

    Energy Technology Data Exchange (ETDEWEB)

    Gallion, P.; Debarge, G.

    1984-04-01

    The influence of quantum phase fluctuations which affect single frequency semiconductor lasers in various coherent detection systems is discussed in terms of photocurrent autocorrelation and spectral density functions. The general treatment given in this paper can be applied in diverse practical cases and points out the problems of phase correlation and phase matching between the two mixed optical beams. In the more general case the photocurrent spectrum is found to be composed of discrete and quasi-Lorentzian parts whose energies and spectral spreads are discussed as a function of the laser line width, the phase matching and the phase correlation between the two coherently combined fields.

  20. Stripe and bubble phases in quantum Hall systems

    OpenAIRE

    Fogler, MM

    2001-01-01

    We present a brief survey of the charge density wave phases of a two-dimensional electron liquid in moderate to weak magnetic fields where several higher Landau levels are occupied. The review follows the chronological development of this new and emerging field: from the ideas that led to the original theoretical prediction of the novel ground states, to their dramatic experimental discovery, to the currently pursued directions and open questions.

  1. Experimentally determined chaotic phase synchronization in a neuronal system

    Science.gov (United States)

    Makarenko, Vladimir; Llinás, Rodolfo

    1998-01-01

    Mathematical analysis of the subthreshold oscillatory properties of inferior olivary neurons in vitro indicates that the oscillation is nonlinear and supports low dimensional chaotic dynamics. This property leads to the generation of complex functional states that can be attained rapidly via phase coherence that conform to the category of “generalized synchronization.” Functionally, this translates into neuronal ensemble properties that can support maximum functional permissiveness and that rapidly can transform into robustly determined multicellular coherence. PMID:9861041

  2. Gas phase chemical detection with an integrated chemical analysis system

    Energy Technology Data Exchange (ETDEWEB)

    CASALNUOVO,STEPHEN A.; FRYE-MASON,GREGORY CHARLES; KOTTENSTETTE,RICHARD; HELLER,EDWIN J.; MATZKE,CAROLYN M.; LEWIS,PATRICK R.; MANGINELL,RONALD P.; BACA,ALBERT G.; HIETALA,VINCENT M.

    2000-04-12

    Microfabrication technology has been applied to the development of a miniature, multi-channel gas phase chemical laboratory that provides fast response, small size, and enhanced versatility and chemical discrimination. Each analysis channel includes a sample preconcentrator followed by a gas chromatographic separator and a chemically selective surface acoustic wave detector array to achieve high sensitivity and selectivity. The performance of the components, individually and collectively, is described.

  3. A new PLL system using full order observer and PLL system modeling in a single phase grid-connected inverter

    DEFF Research Database (Denmark)

    Ko, Youngjong; Park, Kiwoo; Lee, Kyo-Beum

    2011-01-01

    In a grid connected power conversion system, the phase angle information of a grid voltage is very essential for supplying power to the grid since it is used for active and reactive power control. A Phase Locked Loop (PLL) system is used and should be robust because often the actual grid voltages...... are usually distorted by unexpected harmonics. However, conventional PLL systems have steady state errors when distorted voltages are used as a PLL input. Furthermore, using this distorted phase angle in the power control could reduce the output power quality. In this paper, the grid voltages are separated...... into fundamental and harmonic components and a virtual phase voltage is generated from the fundamental component using a Full Order Observer (FOO). Two virtual voltages are used as an input for the PLL system so the phase angle errors can be reduced and the output power quality can be improved. The dynamic...

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

    African Journals Online (AJOL)

    user

    transmission system to low voltage distribution system, quite a good number of series ... Keywords: Active power filter (APF), current source type of harmonic load .... voltage source type harmonic loads are having diode rectifier with smoothing.

  5. A Traction Three-Phase to Single-Phase Cascade Converter Substation in an Advanced Traction Power Supply System

    Directory of Open Access Journals (Sweden)

    Xiaoqiong He

    2015-09-01

    Full Text Available The advanced traction power supply system (ATPSS is a new directional development for traction power supply systems, which can totally remove the neutral sections and effectively promote power quality. However, the existing converters suffer from small substation capacity. In this paper, a new configuration based on a three-level neutral point clamped (3L-NPC three-phase to single-phase cascade converter in a substation is proposed for ATPSS, which can be used to match the capacity of the converter for high voltage and large power applications. The control strategy of the proposed converter is analyzed in depth, and the phase disposition sinusoidal pulse width modulation (PD-SPWM with phase shift carrier SPWM (PSC-SPWM is employed in the inverters. Then, the inductance equalizing circuit is applied for the voltage balance on the DC-link. Besides, a LC filter circuit is designed to eliminate the double line-frequency ripple of DC voltage. Afterwards, a simulation model and an experimental prototype are developed, respectively. The simulation results show that the proposed converter in this paper can not only meet the requirements of voltage and capacity for the traction network, but also improve power quality. Finally, the experimental results verify the correctness and feasibility of the proposed control strategy.

  6. Enhanced Flight Termination System Study Phase I - IV Reports

    Science.gov (United States)

    2002-11-01

    manufactured by Zeta ( EPSCO ) Corp. The CTS equipment is remotely activated by the RSO in the mission control area. The CTS hardware is similar to the...Command Panel System Operations and Maintenance Manual, August 1998. 14. ZETA ( EPSCO ) Command Transmitter System Maintenance Manual for Model 1376...Command Panel System Operations and Maintenance Manual, August 1998. 14. ZETA ( EPSCO ) Command Transmitter System Maintenance Manual for Model 1376

  7. Collins Model and Phase Diagram of 2D Ternary System

    Institute of Scientific and Technical Information of China (English)

    XIE Chuan-Mei; CHEN Li-Rong

    2004-01-01

    The Collins model is introduced into the two-dimensional (2D) alternative ternary system having the Lennard-Jones (L-J) potential. The Gibbs free energy of this ternary system is calculated, and according to thermodynamic theory, a group of equations that determine the solid-liquid diagram of ternary system are derived, some isothermal sectional diagrams of the 2D ternary system are obtained. The results are quite similar to the behavior of three-dimensional substances.

  8. Phase reduction of weakly perturbed limit cycle oscillations in time-delay systems

    Science.gov (United States)

    Novičenko, V.; Pyragas, K.

    2012-06-01

    The phase reduction method is applied to a general class of weakly perturbed time-delay systems exhibiting periodic oscillations. The adjoint equation with an appropriate initial condition for the infinitesimal phase response curve of a time-delay system is derived. The method is demonstrated numerically for the Mackey-Glass equation as well as for a chaotic Rössler system subject to a delayed feedback control (DFC). We show that the profile of the phase response curve of a periodic orbit stabilized by the DFC algorithm does not depend on the control matrix. This property is universal and holds for any dynamical system subject to the DFC.

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

    DEFF Research Database (Denmark)

    Yang, Yongheng; Blaabjerg, Frede

    2015-01-01

    A still booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the demand of “clean” power generation. Grid-connected PV systems will become an even active player in the future mixed power systems, which are linked by a vast of power electronics...

  10. Guidance of Nonlinear Nonminimum-Phase Dynamic Systems

    Science.gov (United States)

    Devasia, Santosh

    1997-01-01

    The first two years research work has advanced the inversion-based guidance theory for: (1) systems with non-hyperbolic internal dynamics; (2) systems with parameter jumps; (3) systems where a redesign of the output trajectory is desired; and (4) the generation of recovery guidance maneuvers.

  11. Project Phase Dependent Configuration of Project Management Information Systems

    OpenAIRE

    Bērziša, S; Grabis, J.

    2012-01-01

    Project management information systems ensure the collection and display of project information. The project information changes depend upon the project environment. According to project environment and requirements, the configuration of project management information system is ensured by means of an approach to configuration of project management information systems. However, topicality of information and access to it change during the project life cycle depending upo...

  12. Compensation of distant phase-distorting layers. I. Narrow-field-of-view adaptive receiver system.

    Science.gov (United States)

    Yu, Miao; Vorontsov, Mikhail A

    2004-09-01

    We analyze various scenarios of adaptive wave-front phase-aberration correction in optical-receiver-type systems when inhomogeneties of the wave propagation medium are either distributed along the propagation path or localized in a few thin layers remotely located from the receiver telescope pupil. Phase-aberration compensation is performed with closed-loop control architectures based on decoupled stochastic parallel gradient descent, stochastic parallel gradient descent, and phase conjugation control algorithms. Both receiver system aperture diffraction effects and the effect of wave-front corrector position on phase-aberration compensation efficiency are analyzed.

  13. On the Relation between Phase-Type Distributions and Positive Systems

    Directory of Open Access Journals (Sweden)

    Kyungsup Kim

    2015-01-01

    Full Text Available The relation between phase-type representation and positive system realization in both the discrete and continuous time is discussed. Using the Perron-Frobenius theorem of nonnegative matrix theory, a transformation from positive realization to phase-type realization is derived under the excitability condition. In order to explain the connection, some useful properties and characteristics such as irreducibility, excitability, transparency, and order reduction for positive realization and phase-type representation are discussed. In addition, the connection between the phase-type renewal process and the feedback positive system is discussed in the stabilization concept.

  14. Phase noise estimation and mitigation for DCT-based coherent optical OFDM systems.

    Science.gov (United States)

    Yang, Chuanchuan; Yang, Feng; Wang, Ziyu

    2009-09-14

    In this paper, as an attractive alternative to the conventional discrete Fourier transform (DFT) based orthogonal frequency division multiplexing (OFDM), discrete cosine transform (DCT) based OFDM which has certain advantages over its counterpart is studied for optical fiber communications. As is known, laser phase noise is a major impairment to the performance of coherent optical OFDM (CO-OFDM) systems. However, to our knowledge, detailed analysis of phase noise and the corresponding mitigation methods for DCT-based CO-OFDM systems have not been reported yet. To address these issues, we analyze the laser phase noise in the DCT-based CO-OFDM systems, and propose phase noise estimation and mitigation schemes. Numerical results show that the proposal is very effective in suppressing phase noise and could significantly improve the performance of DCT-based CO-OFDM systems.

  15. Microwave Oscillator Phase Noise Requirement for TD-SCDMA Wireless Communication Systems

    Institute of Scientific and Technical Information of China (English)

    Song-Bai HE; Xiao-Huan Yan; Jing-Fu Bao

    2007-01-01

    In time division synchronous code division multiple access (TD-SCDMA) wireless communication systems, QPSK or 8PSK has been employed to support high data rate services and high efficiency in available bandwidth. The performance of such systems is affected by the phase noise of the microwave local oscillator. The phase noise model of synthesizer and the RF transceiver model for the phase noise effect are proposed for applications of TD-SCDMA systems. The relationship between the power spectral density (PSD) and root mean square (RMS) phase error is given. Then, the error vector magnitude (EVM) performance is analytically evaluated by using the single side band (SSB) phase noise. Theoretical results show agreement with those obtained by measurement data and therefore can be used to derive the TD-SCDMA system performance.

  16. Comparative assessment of olive oil mill effluents from three-phase and two-phase systems, treated for hydrogen production.

    Science.gov (United States)

    Rouvalis, A; Iliopoulou-Georgudaki, J

    2010-10-01

    By-products of a two-phase and a three-phase olive oil mill process treated in an anaerobic fermentation system for hydrogen production, were evaluated by three bioassays: the zebrafish Danio rerio embryo test and two microbiotests, Thamnotoxkit F and Daphtoxkit F™ pulex. Samples from both processes were classified as "very toxic" with LC(50) values ranging from 1.52% (T. platyurus 24 h test) to 4.48% (D. pulex 48 h-LC₅₀). Toxicity values were differently correlated to physicochemical parameters showing different degree of influence. The treated effluents of both process systems remained very toxic showing the necessity for further treatment, aiming to environmentally safe discharges.

  17. Relative phase noise induced impairment in M-ary phase-shift-keying coherent optical communication system using distributed fiber Raman amplifier.

    Science.gov (United States)

    Cheng, Jingchi; Tang, Ming; Fu, Songnian; Shum, Perry Ping; Liu, Deming

    2013-04-01

    We show for the first time, to the best of our knowledge, that, in a coherent communication system that employs a phase-shift-keying signal and Raman amplification, besides the pump relative intensity noise (RIN) transfer to the amplitude, the signal's phase will also be affected by pump RIN through the pump-signal cross-phase modulation. Although the average pump power induced linear phase change can be compensated for by the phase-correction algorithm, a relative phase noise (RPN) parameter has been found to characterize pump RIN induced stochastic phase noise. This extra phase noise brings non-negligible system impairments in terms of the Q-factor penalty. The calculation shows that copumping leads to much more stringent requirements to pump RIN, and relatively larger fiber dispersion helps to suppress the RPN induced impairment. A higher-order phase-shift keying (PSK) signal is less tolerant to noise than a lower-order PSK.

  18. Thermal analysis and prediction of phase equilibria in ternary Pb-Zn-Ag system

    OpenAIRE

    2011-01-01

    Ternary Pb-Zn-Ag system is typical for some physicochemical processes going on in refining phase in the extractive metallurgy of lead. Therefore, investigation of mentioned system is important from both theoretical and practical research of the phenomena occurring during the lead desilverizing process. The results of experimental investigation using differential thermal analysis (DTA) and thermodynamic calculation of phase equilibria in Pb-Zn-Ag system according to CALPHAD method, in th...

  19. Noether-Form Invariance of Nonholonomic Controllable Mechanical Systems in Phase Space

    Institute of Scientific and Technical Information of China (English)

    XIA Li-Li; LI Yuan-Cheng

    2007-01-01

    In this paper, we study the Noether-form invariance of nonholonomic mechanical controllable systems in phase space. Equations of motion of the controllable mechanical systems in phase space are presented. The definition and the criterion for this system are presented. A new conserved quantity and the Noether conserved quantity deduced from the Noether-form invariance are obtained. An example is given to illustrate the application of the results.

  20. Phase space view of quantum mechanical systems and Fisher information

    Science.gov (United States)

    Nagy, Á.

    2016-06-01

    Pennini and Plastino showed that the form of the Fisher information generated by the canonical distribution function reflects the intrinsic structure of classical mechanics. Now, a quantum mechanical generalization of the Pennini-Plastino theory is presented based on the thermodynamical transcription of the density functional theory. Comparing to the classical case, the phase-space Fisher information contains an extra term due to the position dependence of the temperature. However, for the special case of constant temperature, the expression derived bears resemblance to the classical one. A complete analogy to the classical case is demonstrated for the linear harmonic oscillator.

  1. Expert System for Minefield Site Prediction. Phase 1.

    Science.gov (United States)

    1988-02-01

    2.2111- .25 Jlill 1 MICROCOPY RESOLUTION TLST CHART % %R( % % % % % ko , %% % - Af-A -:A.ZA .A r. ETL-0492 Expert system for minefield site...1. TITLE (Include Security Gassfication) EXPERT SYSTEM FOR MINEFIELD SITE PREDICTION FIRST YEAR REPORT r.. Z. PERSONAL AUTHOR(S) Dillencourt, Michael...identify by block number)FIELD GROUP L SUB-GROUP I Expert System ’ LMinefield,8ite ,rediction - * Quadtree,CTeraiin--nalysis,.t 19, ABSTRACT (Continue on

  2. Development of a rotary instrumentation system, phase 2

    Science.gov (United States)

    Adler, A.; Skidmore, W.

    1982-12-01

    A rotary instrumentation system which consists of ruggedized miniature telemetry transmitters installed on the rotating shaft of a gas turbine engine to telemeter the outputs of sensors (strain gages, thermocouples, etc.) on rotating engine components was designed. A small prototype system, which demonstrates the capabilities of performing in the intended environment and demonstrates that the system is expandable to handle about 100 data channels was developed.

  3. Synchronization Methods for Three Phase Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Timbus, Adrian Vasile; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    Nowadays, it is a general trend to increase the electricity production using Distributed Power Generation Systems (DPGS) based on renewable energy resources such as wind, sun or hydrogen. If these systems are not properly controlled, their connection to the utility network can generate problems...... on the grid side. Therefore, considerations about power generation, safe running and grid synchronization must be done before connecting these systems to the utility network. This paper is mainly dealing with the grid synchronization issues of distributed systems. An overview of the synchronization methods...

  4. Two-phase aqueous micellar systems: an alternative method for protein purification

    Directory of Open Access Journals (Sweden)

    Rangel-Yagui C. O.

    2004-01-01

    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  5. Phase characteristics of electromagnetically induced transparency analogue in coupled resonant systems

    CERN Document Server

    Zhou, Xiaoyan; Pang, Wei; Zhang, Hao; Yang, Qingrui; Zhang, Daihua

    2013-01-01

    Electromagnetically induced transparency (EIT) and EIT-like effects have been investigated in a wide variety of coupled resonant systems. Here, a classification of the phase characteristics of the EIT-like spectral responses is presented. Newly identified phase responses reveal unexplored operation regimes of EIT-like systems. Taking advantage of the new phase regimes, one can obtain group delay, dispersion and nonlinearity properties greatly enhanced by almost one order of magnitude, compared to the traditionally constructed EIT-like devices, which breaks the fundamental limitation (e.g., delay-bandwidth product) intrinsic to atomic EIT and EIT-like effects. Optical devices and electrical circuits are analyzed as examples showing the universality of our finding. We show that cavity-QED-based quantum phase gates can be greatly improved to achieve a phase shift of {\\pi}. The new phase characteristics are also believed to be useful to build novel doubly resonant devices in quantum information based on cavity QE...

  6. Application of Block Copolymer in Three-Liquid-Phase Extraction System

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel three-liquid-phase extraction system (TES) composed of butyl acetate, block copolymer polyethylene oxide-polypropylene oxide-polyethylene oxide and ammonium sulphate aqueous solution [(NH4)2SO4] as top, middle, and bottom phase, respectively, has been developed. The copolymer recycling and partitioning behavior of penicillin V has been studied in this system. Results show that the copolymer could be purified and recycled and penicillin V of the filtrated ferment broth could be partitioned unevenly among the phases and purified in the top phase of this TES. About 90 wt.% of penicillin V could be distributed into the top phase around pH 2.5 and only less than 0.1 wt.% left in the bottom phase.

  7. Linear systems theory for the analysis of phase-shifting algorithms

    Science.gov (United States)

    Estrada, Julio C.; Servín, Manuel; Quiroga, Juan A.

    2010-08-01

    Phase-shifting algorithms are methods used for recovering the modulating phase of an interferogram sequence obtained by Phase Stepping Interferometry (PSI) techniques. Typically, the number of interferograms in a PSI sequence is from 3 to around 9 interferograms, although we can find algorithms that works with more than 9 interferograms. In this paper, we are going to show the analysis and design of phase-shifting algorithms from the point of view of the linear systems paradigm from digital signal processing. We will show how this paradigm describes in a general fashion the phase-shifting algorithm systems, and how we can easily design tunable phase-shifting algorithms using this simple scheme.

  8. Influence of perturbative phase noise on active coherent polarization beam combining system.

    Science.gov (United States)

    Ma, Pengfei; Zhou, Pu; Wang, Xiaolin; Ma, Yanxing; Su, Rongtao; Liu, Zejin

    2013-12-02

    In this manuscript, the influence of perturbative phase noise on active coherent polarization beam combining (CPBC) system is studied theoretically and experimentally. By employing a photo-detector to obtain phase error signal for feedback loop, actively coherent polarization beam combining of two 20 W-level single mode polarization-maintained (PM) fiber amplifiers are demonstrated with more than 94% combining efficiency. Then the influence of perturbative phase noise on active CPBC system is illustrated by incorporating a simulated phase noise signal in one of the two amplifiers. Experimental results show that the combining efficiency of the CPBC system is susceptible to the frequency or amplitude of the perturbative phase noise. In order to ensure the combining efficiency of the unit of CPBC system higher than 90%, the competence of our active phase control module for high power operation is discussed, which suggests that it could be worked at 100s W power level. The relationship between residual phase noise of the active controller and the normalized voltage signal of the photo-detector is developed and validated experimentally. Experimental results correspond exactly with the theoretically analyzed combining efficiency. Our method offers a useful approach to estimate the influence of phase noise on CPBC system.

  9. Wetting controlled phase transitions in two-dimensional systems of colloids

    DEFF Research Database (Denmark)

    Gil, Tamir; Ipsen, John Hjorth; Tejero, T.F.

    1998-01-01

    The phase behavior of disk colloids, embedded in a two-dimensional fluid matrix that undergoes a first-order phase transition, is studied in the complete wetting regime where the thermodynamically metastable fluid phase is stabilized at the surface of the disks. In dilute collections of disks......, the tendency to minimize the extent of the fluid-fluid interface and the extent of the unfavorable wetting phase in the system gives rise to aggregation phenomena and to separation of large domains of disks that have the characteristics of bulk colloidal phases. The conditions for phase transitions among...... cluster gas, liquid, and solid phases of the disk colloids are determined from the corresponding values of the disk chemical potential within an analytic representation of the grand partition function for the excess energy associated with a gas of disk clusters in the low-disk-density limit. The wetting...

  10. The decryption of random phase multiplexing encoding system

    Science.gov (United States)

    Lee, Hsiao-Yi; Liu, Jung-Ping; Chang, Chi-Ching; Yau, Hon-Fai; Chang, Tsung-Chien

    2004-10-01

    Random-phase-multiplexing storage using photorefractive crystals is one of the most important topics in the field of photorefractive optics. To achieve random phase recording, we can use a diffuser to encrypt the reference light in a holographic recording setup. To decrypt the recorded pattern, the same diffuser used in encryption must be used in the reconstruction light, and it must be set in the original orientation. In this way, a number of 2-D patterns can be stored in a single photorefractive crystal with a single diffuser set at different orientations for different patterns. A merit in this recording method is that the encryption is virtually not possible to be decrypted if the original diffuser for encrypting is not available. In this paper, we proposed a way to decrypt the encrypted information in a photorefractive lithium niobate crystal without the possession of the original diffuser. In this method, we suppose somehow we know one of the patterns stored in the crystal, and then we retrieve the original diffuser with this pattern. And ultimately all the other patterns stored in the crystal are decrypted and retrieved with this retrieved diffuser.

  11. Gravity Probe B Timing System and Roll Phase Determination

    Science.gov (United States)

    Jie, Li; Kolodziejczak, Jeffery

    2007-01-01

    An oven-controlled crystal oscillator at 16.368 MHz provides clock signals to all GP-B components and synchronizes the data collection, transmission and processing. The sampled science data signals are stamped with the vehicle time, a counter of the 10Hz data strobe divided down from the clock. The GPS receiver supplies an external reference for time transfer between the vehicle time and coordinated universal time. Ground and space flight tests show the time transfer error is within 1 microsecond. The time latency between the effective sample time of science signals and the stamped vehicle time is verified to 1 ms in the ground tests. The GP-B satellite is controlled to roll with a period of 77.5 sec about an axis along the direction to the guide star to average out the disturbance torques fixed to the body of the satellite and reduce the gyroscope readout noise. The roll phase is determined on the ground to high accuracy with the telemetry data from two star trackers and used in the data analysis to separate the drifts of gyroscope spin axes in the orbital plane and perpendicular to the orbital plane. The flight data shows that the roll phase is controlled to within 40 arcsec with a measurement uncertainty of 7 arcsec.

  12. Modelling and Prioritization of System Risks in Early Project Phases

    NARCIS (Netherlands)

    Rajabali Nejad, Mohammadreza

    2016-01-01

    The rising complexity of product and systems demands further attention to potential Risks. While researchers explore tools and methods to identify system risk, its prioritization remains a challenging task in a multistakeholder environment. Hazard is the source of risk and causes harm. Harm may have

  13. Synchronization Methods for Three Phase Distributed Power Generation Systems

    DEFF Research Database (Denmark)

    Timbus, Adrian Vasile; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    Nowadays, it is a general trend to increase the electricity production using Distributed Power Generation Systems (DPGS) based on renewable energy resources such as wind, sun or hydrogen. If these systems are not properly controlled, their connection to the utility network can generate problems o...

  14. Model validation studies of solar systems, Phase III. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.; Winn, C.B.

    1978-12-01

    Results obtained from a validation study of the TRNSYS, SIMSHAC, and SOLCOST solar system simulation and design are presented. Also included are comparisons between the FCHART and SOLCOST solar system design programs and some changes that were made to the SOLCOST program. Finally, results obtained from the analysis of several solar radiation models are presented. Separate abstracts were prepared for ten papers.

  15. Arizona TeleMedicine Network: System Procurement Specifications, Phase 1.

    Science.gov (United States)

    Atlantic Research Corp., Alexandria, VA.

    Defining the system procurement specifications for a telecommunications system designed to provide health services to rurally isolated American Indians living on reservations in Arizona, this document presents detailed specifications for: (1) a complete communications facility; (2) a mobile health communications treatment and diagnosis unit; (3)…

  16. The Cu-Te-Sb phase system at temperatures between 300 and 1000 degree C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven

    1997-01-01

    Phase relations were determined in the Cu-Te-Sb phase system at 300, 350, 400, 500, 600, 700, 800, 900 and 1000 degree C. At temperatures between 400 and 900 degree C a cubic primitive ternary phase A exists. It has the empirical formula Cu(10.32-0.97x)Te(x)Sb(4-x) (Z=2, a=7.682 Å). A small liquid...

  17. Properties of Phase Transition of Traffic Flow on Urban Expressway Systems with Ramps and Accessory Roads

    Institute of Scientific and Technical Information of China (English)

    梅超群; 刘业进

    2011-01-01

    In this paper, we develop a cellular automaton model to describe the phase transition of traffic flow on urban expressway systems with on-off-ramps and accessory roads. The lane changing rules are given in detailed, the numerical results show that the main road and the accessory road both produce phase transitions. These phase transitions will omen be influenced by the number of lanes, lane changing, the ramp flow, the input flow rate, and the geometry structure.

  18. Phase relationships and materials design in the Ln-Si-Al-O-N system

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Subsolidus phase relationships in the system Ln2O3-Si3N4-AlN-Al2O3, where Ln represents Nd, Sm and Dy, were summarized, with emphasis on the region involving α-sialon, β-sialon and AlN-polytypoid phases. This information is further used in designing the compatible matrix phases of sialon materials with desirable properties. Examples were provided to illustrate the advantage of such a basic approach to materials design.

  19. The Cu-Te-Sb phase system at temperatures between 300 and 1000 degree C

    DEFF Research Database (Denmark)

    Karup-Møller, Sven

    1997-01-01

    Phase relations were determined in the Cu-Te-Sb phase system at 300, 350, 400, 500, 600, 700, 800, 900 and 1000 degree C. At temperatures between 400 and 900 degree C a cubic primitive ternary phase A exists. It has the empirical formula Cu(10.32-0.97x)Te(x)Sb(4-x) (Z=2, a=7.682 Å). A small liqui...

  20. Zero phase error control based on neural compensation for flight simulator servo system

    Institute of Scientific and Technical Information of China (English)

    Liu Jinkun; He Peng; Er Lianjie

    2006-01-01

    Using the future desired input value, zero phase error controller enables the overall system's frequency response exhibit zero phase shift for all frequencies and a small gain error at low frequency range, and based on this, a new algorithm is presented to design the feedforward controller. However, zero phase error controller is only suitable for certain linear system. To reduce the tracking error and improve robustness, the design of the proposed feedforward controller uses a neural compensation based on diagonal recurrent neural network. Simulation and real-time control results for flight simulator servo system show the effectiveness of the proposed approach.

  1. Unconventional phases in quantum spin and pseudospin systems in two dimensional and three dimensional lattices

    Science.gov (United States)

    Xu, Cenke

    Several examples of quantum spin systems and pseudo spin systems have been studied, and unconventional states of matters and phase transitions have been realized in all these systems under consideration. In the p +/- ip superconductor Josephson lattice and the p--band cold atomic system trapped in optical lattices, novel phases which behave similarly to 1+1 dimensional systems are realized, despite the fact that the real physical systems are in two or three dimensional spaces. For instance, by employing a spin-wave analysis together with a new duality transformation, we establish the existence and stability of a novel gapless "critical phase", which we refer to as a "bond algebraic liquid". This novel critical phase is analogous to the 1+1 dimensional algebraic boson liquid phase. The reason for the novel physics is that there is a quasilocal gauge symmetry in the effective low energy Hamiltonian. In a spin-1 system on the kagome lattice, and a hard-core boson system on the honeycomb lattice, the low energy physics is controlled by two components of compact U(1) gauge symmetries that emerge at low energy. Making use of the confinement nature of the 2+1 dimensional compact gauge theories and the powerful duality between gauge theories and height field theories, the crystalline phase diagrams are studied for both systems, and the transitions to other phases are also considered. These phase diagrams might be accessible in strongly correlated materials, or atomic systems in optical lattices. A novel quantum ground state of matter is realized in a bosonic model on three dimensional fcc lattice with emergent low energy excitations. The novel phase obtained is a stable gapless boson liquid phase, with algebraic boson density correlations. The stability of this phase is protected against the instanton effect and superfluidity by self-duality and large gauge symmetries on both sides of the duality. The gapless collective excitations of this phase closely resemble the

  2. Phase diagram determination and thermodynamic modeling of the Cu-Mg-Si system

    Directory of Open Access Journals (Sweden)

    Zhao J.

    2016-01-01

    Full Text Available 13 ternary Cu-Mg-Si alloys were prepared by means of the powder metallurgy method. Phase equilibria at 500 and 700 oC of the Cu-Mg-Si system were determined using X-ray diffraction analysis (XRD. The existence of 3 ternary compounds in this system was verified: CuMgSi_Sigma (Cu16Mg6Si7, Tau (Cu3Mg2Si, and Laves ((Cu0.8Si0.22(Mg0.88Cu0.12. A thermodynamic modeling for the Cu-Mg-Si system was then conducted on the basis of the experimental data obtained in this work and those critically reviewed from the literature. The complex phase relationship between Laves phase and other phases has been successfully modeled in this work. Comparisons between the calculated and the measured phase diagrams show that most of the experimental data can be reproduced by the presently obtained thermodynamic parameters.

  3. Geometric Phase for a Qutrit-Qubit Mixed-Spin System

    Institute of Scientific and Technical Information of China (English)

    WANG Ai-Ping; QIANG Wen-Chao; LING Ya-Wen; XIN Hong; YANG Yong-Ming

    2011-01-01

    @@ We study the geometric phase of a qutrit-qubit mixed-spin system in an external homogeneous magnetic field.Both the spin-spin interaction strength J and the external magnetic field B can affect the geometric phase of the system.In addition,we consider the negativity of the composite system.The relationship between the negativity and the geometric phase is obtained.Finally,we calculate the geometric phase for a thermal mixed state and show how the geometric phase depends on the resealed coupling parameter and temperature.In the limit T→0,we can recover the result of the ground state.This analysis has some implications in realistic implementations of geometric quantum computation.

  4. Prediction of phase equilibria in the In–Sb–Pb system

    Directory of Open Access Journals (Sweden)

    DUSKO MINIC

    2008-03-01

    Full Text Available Binary thermodynamic data, successfully used for phase diagram calculations of the binary systems In–Sb, Pb–Sb and In–Pb, were used for the prediction of the phase equilibria in the ternary In–Sb–Pb system. The predicted equilibrium phase diagram of the vertical Pb–InSb section was compared with the results of differential thermal analysis DTA and optical microscopy. The calculated phase diagram of the isothermal section at 300 °C was compared with the experimentally (SEM, EDX determined composition of phases in the chosen alloys after annealing. Very good agreement between the binary-based thermodynamic prediction and the experimental data was found in all cases. The calculated liquidus projection of the ternary In–Sb–Pb system is also presented.

  5. Preparative crystallization of a single chain antibody using an aqueous two-phase system.

    Science.gov (United States)

    Huettmann, Hauke; Berkemeyer, Matthias; Buchinger, Wolfgang; Jungbauer, Alois

    2014-11-01

    A simultaneous crystallization and aqueous two-phase extraction of a single chain antibody was developed, demonstrating process integration. The process conditions were designed to form an aqueous two-phase system, and to favor crystallization, using sodium sulfate and PEG-2000. At sufficiently high concentrations of PEG, a second phase was generated in which the protein crystallization occurred simultaneously. The single chain antibody crystals were partitioned to the top, polyethylene glycol-rich phase. The crystal nucleation took place in the sodium sulfate-rich phase and at the phase boundary, whereas crystal growth was progressing mainly in the polyethylene glycol-rich phase. The crystals in the polyethylene glycol-rich phase grew to a size of >50 µm. Additionally, polyethylene glycol acted as an anti-solvent, thus, it influenced the crystallization yield. A phase diagram with an undersaturation zone, crystallization area, and amorphous precipitation zone was established. Only small differences in polyethylene glycol concentration caused significant shifts of the crystallization yield. An increase of the polyethylene glycol content from 2% (w/v) to 4% (w/v) increased the yield from approximately 63-87%, respectively. Our results show that crystallization in aqueous two-phase systems is an opportunity to foster process integration.

  6. Energetic Efficiency of Mixing and Mass Transfer in Single Phase and Two-Phase Systems

    Directory of Open Access Journals (Sweden)

    Bałdyga Jerzy

    2017-03-01

    Full Text Available In this work a concept of energetic efficiency of mixing is presented and discussed; a classical definition of mixing efficiency is modified to include effects of the Schmidt number and the Reynolds number. Generalization to turbulent flows is presented as well. It is shown how the energetic efficiency of mixing as well as efficiencies of drop breakage and mass transfer in twophase liquid-liquid systems can be identified using mathematical models and test chemical reactions. New expressions for analyzing efficiency problem are applied to identify the energetic efficiency of mixing in a stirred tank, a rotor stator mixer and a microreactor. Published experimental data and new results obtained using new systems of test reactions are applied. It has been shown that the efficiency of mixing is small in popular types of reactors and mixers and thus there is some space for improvement.

  7. Cooperative Telerobotic Retrieval system Phase 1 technology evaluation report

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R.A.; Croft, K.M.

    1995-03-01

    This document describes the results from the Cooperative Telerobotic Retrieval demonstration and testing conducted at the Idaho National Engineering Laboratory during December 1994 and January 1995. The purpose of the demonstration was to ascertain the feasibility of the system for deploying tools both independently and cooperatively for supporting remote characterization and removal of buried waste in a safe manner and in compliance with all regulatory requirements. The procedures and goals of the demonstration were previously defined in the Cooperative Telerobotic Retrieval System Test Plan for Fiscal Year 1994, which served as a guideline for evaluating the system.

  8. Photonic Delay-line Phase Noise Measurement System

    Science.gov (United States)

    2011-09-01

    combined 500-m and 6-km delay-line measurement system. Noise floor data are shown for the system with and without an EDFA . The laser power was 10 dBm...The optical power into the photodiode was 0 dBm without the EDFA and 11 dBm with it...data are shown for the system with and without an EDFA as well as with a high-power laser. The output optical powers of the low and high-power

  9. The analysis of magnesium oxide hydration in three-phase reaction system

    Science.gov (United States)

    Tang, Xiaojia; Guo, Lin; Chen, Chen; Liu, Quan; Li, Tie; Zhu, Yimin

    2014-05-01

    In order to investigate the magnesium oxide hydration process in gas-liquid-solid (three-phase) reaction system, magnesium hydroxide was prepared by magnesium oxide hydration in liquid-solid (two-phase) and three-phase reaction systems. A semi-empirical model and the classical shrinking core model were used to fit the experimental data. The fitting result shows that both models describe well the hydration process of three-phase system, while only the semi-empirical model right for the hydration process of two-phase system. The characterization of the hydration product using X-Ray diffraction (XRD) and scanning electron microscope (SEM) was performed. The XRD and SEM show hydration process in the two-phase system follows common dissolution/precipitation mechanism. While in the three-phase system, the hydration process undergo MgO dissolution, Mg(OH)2 precipitation, Mg(OH)2 peeling off from MgO particle and leaving behind fresh MgO surface.

  10. Brayton Isotope Power System (BIPS). Phase I. First annual technical report

    Energy Technology Data Exchange (ETDEWEB)

    1976-10-27

    The objective of the BIPS program is to develop a closed gas turbine dynamic conversion system for space application. The baseline system is a 7-year life, 450 lb, 1300 W(e) unit using Brayton cycle hardware developed for the NASA LeRC and two 2400 W(t) Multi-Hundred Watt isotope heat sources developed for the ERDA. Phase I of the three-phase BIPS program is the conceptual design of the flight system, the design, development, and testing of a prototype Ground Demonstration System (GDS). The Mini-Brayton Rotating Unit (Mini-BRU), Mini-BRU Recuperator (MBR), and Heat Source Assembly (HSA) will be integrated into the ground demonstrator loop, and the system will be tested under simulated space conditions at the AiResearch Space Power Laboratory. Successful completion of the Phase I effort in mid 1978 is expected to lead to the Phase II and Phase III follow-on efforts. Phase II is a 24-month effort for the development and qualification of a flight system. Qualification will include testing with an isotope heat source. Phase III is a 12-month effort to fabricate flight-qualified hardware for delivery in April 1981.

  11. Phase segregation in Pb:GeSbTe chalcogenide system

    Science.gov (United States)

    Kumar, J.; Ahmad, M.; Chander, R.; Thangaraj, R.; Sathiaraj, T. S.

    2008-01-01

    Effect of Pb substitution on the amorphous-crystalline transformation temperature, optical band gap and crystalline structure of Ge{2}Sb{2}Te{5} has been studied. In Pb:GeSbTe chalcogenide films prepared by thermal evaporation, an amorphous to crystallization transition is observed at 124, 129, 136 and 138 °C in Pb{0}Ge{20}Sb{24}Te{56}, Pb{1.6}Ge{19}Sb{26}Te{54}, Pb{3}Ge{17}Sb{28}Te{53} and Pb{5}Ge{12}Sb{28}Te{55} respectively. XRD investigations of annealed samples reveal that Pb substitution retains NaCl type crystalline structure of GST but expands the lattice due to large atomic radii. The increase in amorphous-crystalline transformation temperature is followed with the increase in phase segregation. The optical gap shows marginal variations with composition.

  12. North American Land Data Assimilation System Phase 2

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The goal of the North American Land Data Assimilation System (NLDAS) is to construct quality-controlled, and spatially and temporally consistent, land-surface model...

  13. Centrifugal Blower for Personal Air Ventilation System (PAVS) - Phase 1

    Science.gov (United States)

    2015-02-01

    functionality. 15. SUBJECT TERMS COOLING SBIR REPORTS AXIAL FLOW FANS OFF THE SHELF EQUIPMENT BLOWERS LIGHTWEIGHT CENTRIFUGAL FORCE...HEAT STRESS (PHYSIOLOGY) AIR FLOW VENTILATION PORTABLE EQUIPMENT PERSONAL COOLING SYSTEMS EFFICIENCY EVAPORATION INTEGRATED SYSTEMS PROTOTYPES...gH Vn ad s ad s 4 1 4 3     is angular speed (2rpm) V is volumetric flow rate Had is the fan pumping head (in meters) g is the

  14. Solid-liquid phase diagram of disubstituted benzene systems

    Institute of Scientific and Technical Information of China (English)

    黑恩成; 刘国杰

    1995-01-01

    The cooling curves of different compositions of the systems of ortho-chlorotoluene/para-chlorotoluene and ortho-nitrochlorobenzene/para-nitrochlorobenzene are carefully determined by the thermal analysis method. The crystals obtained are also tested. The conclusion that both systems are of simple eutectic diagram but not the solid solution diagram with a minimum melting point is confirmed. The characteristics of the diagram are explained according to the physical and thermodynarmc properties of the components.

  15. Partial phase relationships of Mg-Zn-Ce system at 350 ℃

    Institute of Scientific and Technical Information of China (English)

    HUANG Ming-li; LI Hong-xiao; DING Hua; REN Yu-ping; QIN Gao-wu; HAO Shi-ming

    2009-01-01

    The alloys were prepared in Mg-rich corner of Mg-Zn-Ce system. Partial phase equilibrium relationships of these alloys at 350 ℃ were identified by using scanning electron microscopy(SEM), electron probe microanalysis(EPMA), X-ray diffraction(XRD) analysis and selected area electron diffraction(SAED) pattern analysis of transmission electron microscopy(TEM). Partial isothermal section of Mg-Zn-Ce system in Mg-rich corner was identified. The results show that there is one ternary compound (T-phase) in Mg-Zn-Ce system. The T-phase is a linear ternary compound in which the content of Ce is about 7.7% (molar fraction); while the content of Zn is changed from 19.3% to 43.6% (molar fraction). The crystal structure of T-phase is C-centered orthorhombic. In addition, one two-phase region of Mg+T-phase and one three-phase region of Mg+T-phase+MgZn(Ce) exist in the Mg-rich corner of Mg-Zn-Ce system at 350 ℃.

  16. Energy management based on AM/FM/GIS for phase balancing application on distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, C.-C., E-mail: cckuo@mail.sju.edu.t [Department of Electrical Engineering, Saint John' s University, 499, Sec. 4, TamKing Rd., Taipei, TamSui 25135, Taiwan (China); Chao, Y.-T., E-mail: bv2cr@yahoo.com.t [Department of Information Management, Technology and Science Institute of Northern Taiwan, 2, Xueyuan Rd., Peitou, Taipei 112, Taiwan (China)

    2010-03-15

    Unbalanced feeder systems may deteriorate of power quality, and increase investment and operating costs for distribution systems. The phase swapping method recommends re-phasing circuits of laterals and transformers for making the current and voltage balanced and also reducing feeder loss and voltage drop. In this paper, an application program, based on the automated mapping/facilities management/ geographic information system (AM/FM/GIS) is developed which contains a function of automatically computing Z-bus, load flow and phase balancing of feeders with phase swapping by using easily selecting of feeder on a graphic user interface application. Therefore, the relative data need not be keyed in manually. The presented phase balancing algorithm are based on database and related data structures developed on the AM/FM/GIS and Visual Basic software, which can be integrated into the Tai-Power distribution automation system. Then, the phase balancing algorithm is designed to handle the load patterns and the load of transformers that connect specific feeders when evaluating phase swaps that will result in reduced daily circuit losses over all load points. The proposed application not only can effectively reduce the circuit loss and improves phase balancing, but also enhances power quality efficiently under easily using environment.

  17. A steerable/distance enhanced penetrometer delivery system: Phase II. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    Amini, A.; Shenhar, J.; Lum, K.D.

    1996-05-01

    This report summarizes the phase II work on the Position Location Device (POLO) for penetrometers. Phase II was carried out to generate an integrated design of a full-scale steerable/distance enhanced penetrometer delivery system. Steering provides for the controlled and directional use of the penetrometer, while vibratory thrusting can provide greater penetration ability.

  18. New Phase Regions of Ir-Ru-Ti System with Eutectic-Peritectic Transformation

    Science.gov (United States)

    Lutsyk, V.; Vorob'eva, V.

    2013-12-01

    Special surfaces, corresponding to phase transformation type changing, have been found and designed within six three-phase regions of the system Ti-Ir-Ru with a help of 3D computer model of its T-x-y diagram.

  19. Extraction of peptide tagged cutinase in detergent-based aqueous two-phase systems

    NARCIS (Netherlands)

    Rodenbrock, A.; Selber, K.; Egmond, M.R.; Kula, M.-R.

    2010-01-01

    Detergent-based aqueous two-phase systems have the advantage to require only one auxiliary chemical to induce phase separation above the cloud point. In a systematic study the efficiency of tryptophan-rich peptide tags was investigated to enhance the partitioning of an enzyme to the detergent-rich p

  20. Analysis of Three-Phase Rectifier Systems with Controlled DC-Link Current Under Unbalanced Grids

    DEFF Research Database (Denmark)

    Kumar, Dinesh; Davari, Pooya; Zare, Firuz

    2017-01-01

    Voltage unbalance is the most common disturbance in distribution networks, which give undesirable effects on many grid connected power electronics systems including Adjustable Speed Drive (ASD). Severe voltage unbalance can force three-phase rectifiers into almost single-phase operation, which de...

  1. Implementation of a Proficiency-Based Diploma System in Maine: Phase II--District Level Analysis

    Science.gov (United States)

    Silvernail, David L.; Stump, Erika K.; McCafferty, Anita Stewart; Hawes, Kathryn M.

    2014-01-01

    This report describes the findings from Phase II of a study of Maine's implementation of a proficiency-based diploma system. At the request of the Joint Standing Committee on Education and Cultural Affairs of the Maine Legislature, the Maine Policy Research Institute (MEPRI) has conducted a two-phased study of the implementation of Maine law…

  2. Symmetrical components and power analysis for a two-phase microgrid system

    DEFF Research Database (Denmark)

    Alibeik, M.; Santos Jr., E. C. dos; Blaabjerg, Frede

    2014-01-01

    This paper presents a mathematical model for the symmetrical components and power analysis of a new microgrid system consisting of three wires and two voltages in quadrature, which is designated as a two-phase microgrid. The two-phase microgrid presents the following advantages: 1) constant power...

  3. Feasibility study of phase-contrast cone beam CT imaging systems

    Science.gov (United States)

    Cai, Weixing

    Attenuation-based x-ray imaging techniques have been developed for many decades. One of the state-of-the-art imaging modalities is the cone beam computed tomography (CBCT) that efficiently scans an object and reproduces high-resolution and isotropic three-dimensional images of it. However, attenuation-based imaging shows a limitation in soft tissue imaging where the absorption contrast is low. Recently several phase-contrast techniques have been developed that are expected to improve low-contrast details by using the phase information of the object. The idea of this thesis is to incorporate the phase-contrast techniques into the current cone beam CT systems to combine the advantages of both phase-contrast imaging and CBCT. From a practical view of medical imaging, two phase-contrast cone beam CT systems are proposed by using the in-line phase-contrast technique and the differential phase-contrast technique, respectively. An in-line phase-contrast image is a Fresnel diffraction pattern in the near field. The image is edge-enhanced, and for soft tissues it is possible to retrieve the phase projection from a single in-line image. Therefore, this technique can be utilized in either of two methods. The first method is to produce edge-enhanced reconstruction images of the attenuation coefficient, and the second is to reconstruct the phase coefficient using the retrieved phase projections. In order to investigate this modality, computer simulations were performed for both working modes. The results using the in-line phase-contrast technique demonstrate superior image quality than that of the attenuation-based technique. A bench-top in-line PC-CBCT system was designed and constructed on top of an optical table, and a simple phantom was imaged and reconstructed using both modes to validate the principle of the proposed imaging scheme. The grating-based differential phase-contrast technique is able to produce the first derivative of phase projections using the principle of

  4. Phase synchronization of oscillations in cardiovascular and respiratory systems in humans

    Science.gov (United States)

    Tankanag, Arina V.; Grinevich, Andrey A.; Tikhonova, Irina V.; Chaplygina, Alina V.; Chemeris, Nikolay K.

    2017-04-01

    Phase synchronization between blood flow oscillations of left and right forearm skin sites, heart rate variability (HRV) and breath rate were studied from healthy volunteers at rest. The degree of synchronization between the phases of the analyzed signals was estimated from the value of the wavelet phase coherence. High medians of values of phase wavelet coherence function were obtained for the endothelial, neurogenic, myogenic and cardiac intervals. Significant phase synchronization were demonstrated between HRV and skin blood flow oscillations in both left and right forearms in a wide frequency range from 0.04 to 0.4 Hz. Six participants exhibited low phase synchronization (rate and HRV, while nine participants had high phase synchronization (> 0.5). This distribution was not affected by the sex or sympathovagal status of volunteers. Participants with low phase synchronization between breath rate and HRV featured low phase synchronization (rate and blood flow oscillations in both forearms. Contrariwise, in subjects with high phase synchronization between respiratory rhythm and HRV both low and high phase synchronization between breath rate and blood flow oscillations in both forearms was observed. The results obtained allow us to suggest that the organism possesses a mechanism mediating the synchronization of blood flow oscillations in the skin microvasculature with all other periodical processes across the cardiovascular system, in particular, with HRV and breath rate over a wide frequency range.

  5. The Effect of pH Difference Between Two Phases on the Partition of Lysozyme in Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the investigation of effect of KSCN on the partitioning of lysozyme in PEG2000/ammonium sulfate aqueous two-phase system, it was found that the KSCN could alter the pH difference between the two phases, and thus affect the partition of lysozyme. The relationship between partition coefficients of lysozyme and pH differences between two phases was discussed.

  6. Modelling production system architectures in the early phases of product development

    DEFF Research Database (Denmark)

    Guðlaugsson, Tómas Vignir; Martin Ravn, Poul; Mortensen, Niels Henrik;

    2016-01-01

    on – leading to an improved basis for prioritizing activities in the project. Requirements for the contents of the framework are presented, and literature on production and system models is reviewed. The production system architecture modelling framework is founded on methods and approaches in literature......This article suggests a framework for modelling a production system architecture in the early phases of product development.The challenge in these phases is that the products to be produced are not completely defined and yet decisions need to be made early in the process on what investments...... and adjusted to fit the modelling requirements of a production system architecture at an early phase of development. The production system architecture models capture and describe the structure, capabilities and expansions of the production system architecture underdevelopment. The production system...

  7. High-pressure sapphire cell for phase equilibria measurements of CO2/organic/water systems.

    Science.gov (United States)

    Pollet, Pamela; Ethier, Amy L; Senter, James C; Eckert, Charles A; Liotta, Charles L

    2014-01-24

    The high pressure sapphire cell apparatus was constructed to visually determine the composition of multiphase systems without physical sampling. Specifically, the sapphire cell enables visual data collection from multiple loadings to solve a set of material balances to precisely determine phase composition. Ternary phase diagrams can then be established to determine the proportion of each component in each phase at a given condition. In principle, any ternary system can be studied although ternary systems (gas-liquid-liquid) are the specific examples discussed herein. For instance, the ternary THF-Water-CO2 system was studied at 25 and 40 °C and is described herein. Of key importance, this technique does not require sampling. Circumventing the possible disturbance of the system equilibrium upon sampling, inherent measurement errors, and technical difficulties of physically sampling under pressure is a significant benefit of this technique. Perhaps as important, the sapphire cell also enables the direct visual observation of the phase behavior. In fact, as the CO2 pressure is increased, the homogeneous THF-Water solution phase splits at about 2 MPa. With this technique, it was possible to easily and clearly observe the cloud point and determine the composition of the newly formed phases as a function of pressure. The data acquired with the sapphire cell technique can be used for many applications. In our case, we measured swelling and composition for tunable solvents, like gas-expanded liquids, gas-expanded ionic liquids and Organic Aqueous Tunable Systems (OATS)(1-4). For the latest system, OATS, the high-pressure sapphire cell enabled the study of (1) phase behavior as a function of pressure and temperature, (2) composition of each phase (gas-liquid-liquid) as a function of pressure and temperature and (3) catalyst partitioning in the two liquid phases as a function of pressure and composition. Finally, the sapphire cell is an especially effective tool to gather

  8. Quantum phase transitions about parity breaking in matrix product systems%Quantum phase transitions about parity breaking in matrix product systems

    Institute of Scientific and Technical Information of China (English)

    ZHU Jing-Min

    2011-01-01

    According to our scheme to construct quantum phase transitions (QPTs) in spin chain systems with matrix product ground states, we first successfully combine matrix product state (MPS) QPTs with spontaneous symmetry breaking. For a concrete model, we take

  9. Computerized Operator Support SystemPhase II Development

    Energy Technology Data Exchange (ETDEWEB)

    Ulrich, Thomas A.; Boring, Ronald L.; Lew, Roger T.; Thomas, Kenneth D.

    2015-02-01

    A computerized operator support system (COSS) prototype for nuclear control room process control is proposed and discussed. The COSS aids operators in addressing rapid plant upsets that would otherwise result in the shutdown of the power plant and interrupt electrical power generation, representing significant costs to the owning utility. In its current stage of development the prototype demonstrates four advanced functions operators can use to more efficiently monitor and control the plant. These advanced functions consist of: (1) a synthesized and intuitive high level overview display of system components and interrelations, (2) an enthalpy-based mathematical chemical and volume control system (CVCS) model to detect and diagnose component failures, (3) recommended strategies to mitigate component failure effects and return the plant back to pre-fault status, and (4) computer-based procedures to walk the operator through the recommended mitigation actions. The COSS was demonstrated to a group of operators and their feedback was collected. The operators responded positively to the COSS capabilities and features and indicated the system would be an effective operator aid. The operators also suggested several additional features and capabilities for the next iteration of development. Future versions of the COSS prototype will include additional plant systems, flexible computer-based procedure presentation formats, and support for simultaneous component fault diagnosis and dual fault synergistic mitigation action strategies to more efficiently arrest any plant upsets.

  10. Phase 1 Space Fission Propulsion System Testing and Development Progress

    Science.gov (United States)

    VanDyke, Melissa; Houts, Mike; Godfroy, Tom; Dickens, Ricky; Poston, David; Kapernick, Rick; Reid, Bob; Salvail, Pat; Ring, Peter; Schafer, Charles (Technical Monitor)

    2001-01-01

    Successful development of space fission systems requires an extensive program of affordable and realistic testing. In addition to tests related to design/development of the fission system, realistic testing of the actual flight unit must also be performed. If the system is designed to operate within established radiation damage and fuel burn up limits while simultaneously being designed to allow close simulation of heat from fission using resistance heaters, high confidence in fission system performance and lifetime can be attained through a series of non-nuclear tests. The Safe Affordable Fission Engine (SAFE) test series, whose ultimate goal is the demonstration of a 300 kW flight configuration system, has demonstrated that realistic testing can be performed using non-nuclear methods. This test series, carried out in collaboration with other NASA centers, other government agencies, industry, and universities, successfully completed a testing program with a 30 kWt core, Stirling engine, and ion engine configuration. Additionally, a 100 kWt core is in fabrication and appropriate test facilities are being reconfigured. This paper describes the current SAFE non-nuclear tests, which includes test article descriptions, test results and conclusions, and future test plans.

  11. Multivariable Decoupling Control System Based on Generalized Diagonal Dominance

    Directory of Open Access Journals (Sweden)

    S. Jamebozorg

    2015-03-01

    Full Text Available In this paper, the design of static precompensator for the reduction of interaction in linear multivariable systems is proposed. In the previous studies, the diagonal dominance of systems in special frequency range has been less paid attention to. In the proposed method, some static compensators with matrix coefficients are combined so that the final static compensator can make system diagonal dominance in a wide range of frequencies. These coefficients are obtained with optimization algorithm. In this method, to achieve diagonal dominance with less conservativeness, the criterion of generalized diagonal dominance is used. The proposed method does not have any limitation for systems with high interaction or non-minimum phase systems. In comparison with some common methods, it has a simpler structure with easy implementation. Simulation examples demonstrate the usefulness of the proposed method

  12. Ionic liquids for two-phase systems and their application for purification, extraction and biocatalysis.

    Science.gov (United States)

    Oppermann, Sebastian; Stein, Florian; Kragl, Udo

    2011-02-01

    The development of biotechnological processes using novel two-phase systems based on molten salts known as ionic liquids (ILs) got into the focus of interest. Many new approaches for the beneficial application of the interesting solvent have been published over the last years. ILs bring beneficial properties compared to organic solvents like nonflammability and nonvolatility. There are two possible ways to use the ILs: first, the hydrophobic ones as a substitute for organic solvents in pure two-phase systems with water and second, the hydrophilic ones in aqueous two-phase systems (ATPS). To effectively utilise IL-based two-phase systems or IL-based ATPS in biotechnology, extensive experimental work is required to gain the optimal system parameters to ensure selective extraction of the product of interest. This review will focus on the most actual findings dealing with the basic driving forces for the target extraction in IL-based ATPS as well as presenting some selected examples for the beneficial application of ILs as a substitute for organic solvents. Besides the research focusing on IL-based two-phase systems, the "green aspect" of ILs, due to their negligible vapour pressure, is widely discussed. We will present the newest results concerning ecotoxicity of ILs to get an overview of the state of the art concerning ILs and their utilisation in novel two-phase systems in biotechnology.

  13. Dependence of chymosin and pepsin partition coefficient with phase volume and polymer pausidispersity in polyethyleneglycol-phosphate aqueous two-phase system.

    Science.gov (United States)

    Spelzini, Darío; Picó, Guillemo; Farruggia, Beatriz

    2006-08-01

    The influence of the phase volume ratio and polymer pausidispersity on chymosin and pepsin partition in polyethylenglycol-phosphate aqueous two-phase systems was studied. Both proteins showed a high affinity for the polyethylenglycol rich phase with a partition coefficient from 20 to 100 for chymosin and from 20 to 180 for pepsin, when the polyethyleneglycol molecular mass in the system varied between 1450 and 8000. The partition coefficient of chymosin was not affected by the volume phase ratio, while the pepsin coefficient showed a significant decrease in its partition coefficient with the increase in the top/bottom phase volume ratio.

  14. Magnetic suspension and balance system advanced study, phase 2

    Science.gov (United States)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1990-01-01

    The design improvements for the system encompass 14 or 18 external superconductive coils mounted on a 8 x 8 foot wind tunnel, a superconductive model core magnet on a holmium mandrel to fit an F-16 model, model wings of permanent magnet material Nd2Fe14B, and fiber glass epoxy structure. The Magnetic Suspension and Balance System (MSBS) advanced design is confirmed by the successful construction and test of a full size superconductive model core solenoid with holmium mandrel. The solenoid is 75 cm long and 12.6 cm in diameter and produces 6.1 tesla for a hold time of 47 minutes. An integrated coil system design of a new compact configuration without specific coils for roll or pitch shows promise of simplicity; magnet reductions of 30 percent compared to the most recent 1985 design are possible.

  15. Modular photovoltaic stand-alone systems: Phase 1

    Science.gov (United States)

    Naff, G. J.; Marshall, N. A.

    1983-01-01

    A family of modular stand-alone power systems that covered the range in power level from 1 kw to 14 kw was developed. Products within this family were required to be easily adaptable to different environments and applications, and were to be both reliable and cost effective. Additionally, true commonality in hardware was to be exploited, and unnecessary recurrence of design and development costs were to be minimized; thus improving hardware availability. Assurance of compatibility with large production runs, was also an underlying program goal. A secondary objective was to compile, evaluate, and determine the economic and technical status of available, and potentially available, technology options associated with the balance of systems (BOS) for stand-along photovoltaic (PV) power systems. The secondary objective not only directly supported the primary but additionally contributed to the definition and implementation of the BOS cost reduction plan.

  16. Development of a Dispatchable PV Peak Shainv System. PV: Bonus Program - Phase 1 Report. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    None

    1995-10-01

    This report summarizes the work performed by Delmarva Power and Light and its subcontractors in Phase 1 of the US Department of Energy's PV:BONUS Program. The purpose of the program is to develop products and systems for buildings which utilize photovoltaic (N) technology. Beginning with a cooperative research effort with the University of Delaware's Center for Energy and Environmental Policy Research Delmarva Power developed and demonstrated the concept of Dispatchable PV Peak Shaving. This concept and the system which resulted horn the development work are unique from other grid-connected PV systems because it combines a PV, battery energy storage, power conversion and control technologies into an integrated package. Phase 1 began in July 1993 with the installation of a test and demonstration system at Delmarva's Northern Division General Office building near Newark, Delaware. Following initial testing throughout the summer and fall of 1993, significant modifications were made under an amendment to the DOE contract. Work on Phase 1 concluded in the early spring of 1995. Significant progress towards the goal of commercializing the system was made during Phase 1, and is summarized. Based on progress in Phase 1, a proposal to continue the work in Phase 2 was submitted to the US DOE in May 1995. A contract amendment and providing funds for the Phase 2 work is expected in July 1995.

  17. Phase diagram of the Y–Y{sub 2}Se{sub 3} system, enthalpies of phase transformations

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, O.V.; Kharitontsev, V.B. [Tyumen State University (Russian Federation); Polkovnikov, A.A., E-mail: a.a.polkovnikov@yandex.ru [Tyumen State University (Russian Federation); Elyshev, A.V. [Tyumen State University (Russian Federation); Andreev, P.O. [Tyumen State Oil and Gas University (Russian Federation)

    2015-10-15

    A phase diagram for the Y–Y{sub 2}Se{sub 3} system has been constructed in which the YSe and Y{sub 2}Se{sub 3} phases melt congruently. The daltonide type YSe phase (ST Y{sub 0,75}Se, a=1.1393 nm, melting point=2380 K, H=2200 MPa) forms a double-sided solid solution from 49–50–53 at% Se. In the 50–53 at% Se range, the unit cell parameter increases to 1.1500 nm, the microhardness increases to 4100 MPa and electrical resistivity increases from 0.018 to 0.114 Ω m. These changes are caused by the dominating influx of newly formed structural cationic vacancies arising from the selenium anions that are surplus for the 1:1 Y:Se stoichiometry. The full-valence Y{sub 2}Se{sub 3} composition exists as a low-temperature modification of ε-Y{sub 2}Se{sub 3} (ST Sc{sub 2}S{sub 3}, a=1.145 nm, b=0.818 nm, c=2.438 nm, melting point=1780 K, ∆fusion enthalpy=4±0.4 J/g) and transforms into a modification of ξ-Y{sub 2}Se{sub 3} that does not undergo fixing by thermo-hardening. The eutectic melting point between the YSe and Y{sub 2}Se{sub 3} phases is 1625±5 K, with a eutectic composition that is assumed to be 57.5 at% Se and have an enthalpy of fusion of 43±4.3 J/g. The eutectic for the Y and YSe phases appears at a temperature of 1600 K and 5 at% Se. - Highlights: • Phase equilibria in the Y–Y{sub 2}Se{sub 3} system from 1000 K to melt were studies. • High-temperature polymorphic transition for Y{sub 2}Se{sub 3} were observed. • Singular points in solid solutions areas for YSe and Y{sub 2}Se{sub 3} were found.

  18. Modeling of gamma/gamma-prime phase equilibrium in the nickel-aluminum system

    Science.gov (United States)

    Sanchez, J. M.; Barefoot, J. R.; Jarrett, R. N.; Tien, J. K.

    1984-01-01

    A theoretical model is proposed for the determination of phase equilibrium in alloys, taking into consideration dissimilar lattice parameters. Volume-dependent pair interactions are introduced by means of phenomenological Lennard-Jones potentials and the configurational entropy of the system is treated in the tetrahedron approximation of the cluster variation method. The model is applied to the superalloy-relevant, nickel-rich, gamma/gamma-prime phase region of the Ni-Al phase diagram. The model predicts reasonable values for the lattice parameters and the enthalpy of formation as a function of composition, and the calculated phase diagram closely approximates the experimental diagram.

  19. Laves-phase structural changes in the system CaAl2-xMgx.

    Science.gov (United States)

    Amerioun, Shahrad; Simak, Sergei I; Häussermann, Ulrich

    2003-03-10

    Compounds CaAl(2)(-)(x)Mg(x) (0 Laves phase structures MgCu(2) --> MgNi(2) --> MgZn(2) is revealed. The homogeneity ranges of the underlying phases were determined to be 0 Laves phase structures very well. Structural changes in the quasi-binary system CaAl(2)(-)(x)Mg(x) are induced by the electron concentration, which decreases with increasing x. The stability of the different Laves phase structures as a function of electron concentration was analyzed by the method of moments.

  20. Absolute Definition of Phase Shift in the Elastic Scattering of a Particle from Compound Systems

    Science.gov (United States)

    Temkin, A.

    1961-01-01

    The projection of the target wave function on the total wave function of a scattered particle interacting with the target system is used to define an absolute phase shift including any multiples of pi. With this definition of the absolute phase shift, one can prove rigorously in the limit of zero energy for s-wave electrons scattered from atomic hydrogen that the triplet phase shift must approach a nonzero multiple of pi. One can further show that at least one pi of this phase shift is not connected with the existence of a bound state of the H- ion.

  1. Effects of Concentration and Conformation of Surfactants on Phase Separation of Surfactant-Water-Oil Systems

    Institute of Scientific and Technical Information of China (English)

    袁银权; 邹宪武; 刘昊阳

    2004-01-01

    The effects of surfactants on the phase separation of surfactant-water-oil systems have been investigated by using discontinuous molecular dynamic simulations. The phase separation speed and equilibrium configuration are dependent on the surfactant concentration and conformation. The equilibrium concentration of surfactants at the interface remains constant. With the increasing surfactant concentration, the equilibrium configuration crosses over from the disperse phase to the bicontinuous one. The crossover concentration is estimated. The conformation of the surfactant has little effect on the equilibrium concentration of surfactants at the interface,while it affects the equilibrium configuration after phase separation.

  2. Aircraft wire system laboratory development : phase I progress report.

    Energy Technology Data Exchange (ETDEWEB)

    Dinallo, Michael Anthony; Lopez, Christopher D.

    2003-08-01

    An aircraft wire systems laboratory has been developed to support technical maturation of diagnostic technologies being used in the aviation community for detection of faulty attributes of wiring systems. The design and development rationale of the laboratory is based in part on documented findings published by the aviation community. The main resource at the laboratory is a test bed enclosure that is populated with aged and newly assembled wire harnesses that have known defects. This report provides the test bed design and harness selection rationale, harness assembly and defect fabrication procedures, and descriptions of the laboratory for usage by the aviation community.

  3. Speed-sensorless control strategy for multi-phase induction generator in wind energy conversion systems

    Directory of Open Access Journals (Sweden)

    Dumnić Boris P.

    2016-01-01

    Full Text Available Renewable energy sources, especially wind energy conversion systems (WECS, exhibit constant growth. Increase in power and installed capacity led to advances in WECS topologies. Multi-phase approach presents a new development direction, with several key advantages over three-phase systems. Paired with a sensorless control strategy, multi-phase machines are expected to take primacy over standard solutions. This paper presents speed sensorless vector control of an asymmetrical six-phase induction generator based on a model reference adaptive system (MRAS. Suggested topology and developed control algorithm show that sensorless control can yield appropriate dynamic characteristics for the use in WECS with increase in reliability and robustness. [Projekat Ministarstva nauke Republike Srbije, br. III 042004: Smart Electricity Distribution Grids Based on Distribution Management System and Distributed Generation

  4. Reducing the phase sensitivity of laser-based optical reservoir computing systems.

    Science.gov (United States)

    Nguimdo, Romain Modeste; Verschaffelt, Guy; Danckaert, Jan; Van der Sande, Guy

    2016-01-25

    Optical implementations of reservoir computing systems are very promising because of their high processing speeds and the possibility to process several tasks in parallel. These systems can be implemented using semiconductor lasers subject to optical delayed feedback and optical injection. While the amount of the feedback/injection can be easily controlled, it is much more difficult to control the optical feedback/injection phase. We present extensive numerical investigations of the influence of the feedback/injection phases on laser-based reservoir computing systems with feedback. We show that a change in the phase can lead to a strong reduction in the reservoir computing system performance. We introduce a new readout layer design that -at least for some tasks- reduces this sensitivity to changes in the phase. It consists in optimizing the readout weights from a coherent combination of the reservoir's readout signal and its delayed version rather than only from the reservoir's readout signal as is usually done.

  5. Non-Abelian Geometrical Phase for General Three-Dimensional Quantum Systems

    CERN Document Server

    Mostafazadeh, A

    1996-01-01

    Adiabatic $U(2)$ geometric phases are studied for arbitrary quantum systems with a three-dimensional Hilbert space. Necessary and sufficient conditions for the occurrence of the non-Abelian geometrical phases are obtained without actually solving the full eigenvalue problem for the instantaneous Hamiltonian. The parameter space of such systems which has the structure of $\\xC P^2$ is explicitly constructed. The results of this article are applicable for arbitrary multipole interaction Hamiltonians $H=Q^{i_1,\\cdots i_n}J_{i_1}\\cdots J_{i_n}$ and their linear combinations for spin $j=1$ systems. In particular it is shown that the nuclear quadrupole Hamiltonian $H=Q^{ij}J_iJ_j$ does actually lead to non-Abelian geometric phases for $j=1$. This system, being bosonic, is time-reversal-invariant. Therefore it cannot support Abelian adiabatic geometrical phases.

  6. Phase Diagram and Electronic Structure of Praseodymium and Plutonium systems

    Science.gov (United States)

    Yao, Yong-Xin; Nicola, Lanata; Wang, Cai-Zhuang; Kotliar, Gabriel; Ho, Kai-Ming

    2015-03-01

    We apply a new implementation of LDA +Gutzwiller to calculate the zero-temperature phase diagram and electronic structure of Pr and Pu. Our study of Pr indicates that its pressure-induced volume-collapse transition would not occur without change of lattice structure -- contrarily to Ce. Our study of Pu shows that the most important effect originating the differentiation between the equilibrium densities of its allotropes is the competition between the Peierls effect and the Madelung interaction. However, the proper treatment of electron correlation effects is crucial to reach good agreement with experiment. A similar interplay between correlation effects and bands structure is also displayed in Pr, and might emerge in even greater generality. N.L. and G.K. supported by U.S. DOE BES under Grant No. DE-FG02- 99ER45761. Research at Ames Lab supported by the U.S. DOE, Office of BES, DMSE, Ames Laboratory is operated for the U.S. DOE by Iowa State University under Contract No. DE-AC02-07CH11358.

  7. Optimisation of Transmission Systems by use of Phase Shifting Transformers

    Energy Technology Data Exchange (ETDEWEB)

    Verboomen, J.

    2008-10-13

    In this thesis, transmission grids with PSTs (Phase Shifting Transformers) are investigated. In particular, the following goals are put forward: (a) The analysis and quantification of the impact of a PST on a meshed grid. This includes the development of models for the device; (b) The development of methods to obtain optimal coordination of several PSTs in a meshed grid. An objective function should be formulated, and an optimisation method must be adopted to solve the problem; and (c) The investigation of different strategies to use a PST. Chapter 2 gives a short overview of active power flow controlling devices. In chapter 3, a first step towards optimal PST coordination is taken. In chapter 4, metaheuristic optimisation methods are discussed. Chapter 5 introduces DC load flow approximations, leading to analytically closed equations that describe the relation between PST settings and active power flows. In chapter 6, some applications of the methods that are developed in earlier chapters are presented. Chapter 7 contains the conclusions of this thesis, as well as recommendations for future work.

  8. An Exact Solution and the Pancharatnam Phase for the Generalized Two-Mode Optical System

    Institute of Scientific and Technical Information of China (English)

    侯邦品; 王顺金; 余万伦

    2002-01-01

    Using the algebraic dynamical method, we obtain the exact solution for the generalized two-mode optical system. From the solution, the Pancharatnam phase and the mean values of the number operators of the system are calculated. It is emphasized that the system can be used as a quantum memory.

  9. A framework for the design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Shaw, Andrew; Hodges, George;

    2012-01-01

    A generic modelling framework for phase transition catalyst based reacting systems has been developed and converted into a software tool. The modelling framework accommodates models of different types representing different sub-systems of the PTCbased reactive system; databases of model parameter...

  10. A framework for the design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Shaw, Andrew; Hodges, George;

    A generic modelling framework for phase transition catalyst based reacting systems has been developed and converted into a software tool. The modelling framework accommodates models of different types representing different sub-systems of the PTCbased reactive system; databases of model parameter...

  11. Entropy-Driven Phase Transitions in Colloidal Systems

    NARCIS (Netherlands)

    Ni, R.

    2012-01-01

    This thesis can be divided into two independent parts. In the first part of this thesis, we focus on studying the kinetic pathways of nucleation in colloidal systems. In Chapter 2, we briefly introduce the relevant theory of nucleation, i.e., classic nucleation theory. Then in Chapter 3, we investig

  12. Enhanced power quality based single phase photovoltaic distributed generation system

    Science.gov (United States)

    Panda, Aurobinda; Pathak, M. K.; Srivastava, S. P.

    2016-08-01

    This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.

  13. Entropy-Driven Phase Transitions in Colloidal Systems

    NARCIS (Netherlands)

    Ni, R.

    2012-01-01

    This thesis can be divided into two independent parts. In the first part of this thesis, we focus on studying the kinetic pathways of nucleation in colloidal systems. In Chapter 2, we briefly introduce the relevant theory of nucleation, i.e., classic nucleation theory. Then in Chapter 3, we

  14. Retention Characteristics for Multiple-PhaseFluid Systems

    Directory of Open Access Journals (Sweden)

    Chia-Hsing Tsai and Gour-Tsyh Yeh

    2012-01-01

    Full Text Available The key objective of this paper is to point out that a widely used constitutive relationship between the degrees of saturation and capillary pressures for three-phasefluids over the past twenty five years has resulted in an undue constraint. To our knowledge, this constraint is neither physically justifiable nor is it theoretically supported. The discovery of the undue constraint leads this investigation to develop a viable parametric model to describe the constitutive relationship for a system of multiple fluids. Based on the physical consideration wherein fluid wettability follows a sequence, the proposed parametric model can be easily applied to any system of L arbitrary fluids. Three aspects are presented to confirm the plausibility and completeness of the model. First, the proposed closed-form expression of the saturation-capillary pressure head relationship is identical to van _ renowned model for two-phasefluid systems. Second, a constraint appearing in the widely used model is alleviated in the proposed model. Third, seven hypothetical examples are used to demonstrate that there is no need to impose the constraint on the sequence of capillary pressures. The results show the plausibility and completeness of the model for systems of multiple fluids. The proposed parametric model is a feasible analytic model which provides a generalized saturation-capillary pressure head relationship for any system with regard to multiple fluids. Hopefully, this study will pave a way for others to conduct experiments to validate the model further or develop other better non-constrained models based on experimental evidence.

  15. Global phase synchronization in an array of time-delay systems.

    Science.gov (United States)

    Suresh, R; Senthilkumar, D V; Lakshmanan, M; Kurths, J

    2010-07-01

    We report the identification of global phase synchronization (GPS) in a linear array of unidirectionally coupled Mackey-Glass time-delay systems exhibiting highly non-phase-coherent chaotic attractors with complex topological structure. In particular, we show that the dynamical organization of all the coupled time-delay systems in the array to form GPS is achieved by sequential synchronization as a function of the coupling strength. Further, the asynchronous ones in the array with respect to the main sequentially synchronized cluster organize themselves to form clusters before they achieve synchronization with the main cluster. We have confirmed these results by estimating instantaneous phases including phase difference, average phase, average frequency, frequency ratio, and their differences from suitably transformed phase coherent attractors after using a nonlinear transformation of the original non-phase-coherent attractors. The results are further corroborated using two other independent approaches based on recurrence analysis and the concept of localized sets from the original non-phase-coherent attractors directly without explicitly introducing the measure of phase.

  16. Characterization of electromechanical actuator implemented to phase-shift system applied to a Michelson interferometer

    Science.gov (United States)

    Barcelata-Pinzon, A.; Meneses Fabian, C.; Juarez-Salazar, R.; Durán-Sánchez, M.; Alvarez-Tamayo, R. I.; Robledo-Sánchez, C. I.; Muñoz-Mata, J. L.; Casco-Vázquez, J. F.

    2016-05-01

    Numerical results are presented to show the characterization of an electromechanical actuator capable to achieve equally spaced phase shifts and fraction linear wavelength displacements aided by an interface and a computational system. Measurements were performed by extracting the phase with consecutive interference patterns obtained in a Michelson arrangement setup. This paper is based in the use of inexpensive resources on stability adverse conditions to achieve similar results to those obtained with high-grade systems.

  17. Phase Modulation for postcompensation of dispersion in 160-Gb/s systems

    DEFF Research Database (Denmark)

    Siahlo, Andrei; Clausen, A. T.; Oxenløwe, Leif Katsuo

    2005-01-01

    Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end.......Tunable postcompensation of second-order dispersion by sinusoidal phase modulation is realized for a 160-Gb/s optical transmission system. Accumulated dispersions with magnitudes up to 4 ps/nm are compensated in the receiver end....

  18. Thermomorphic phase separation in ionic liquid-organic liquid systems - conductivity and spectroscopic characterization

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Berg, Rolf W.;

    2005-01-01

    Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl-imidazolium io......Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl...

  19. Stochastic pump effect and geometric phases in dissipative and stochastic systems

    Energy Technology Data Exchange (ETDEWEB)

    Sinitsyn, Nikolai [Los Alamos National Laboratory

    2008-01-01

    The success of Berry phases in quantum mechanics stimulated the study of similar phenomena in other areas of physics, including the theory of living cell locomotion and motion of patterns in nonlinear media. More recently, geometric phases have been applied to systems operating in a strongly stochastic environment, such as molecular motors. We discuss such geometric effects in purely classical dissipative stochastic systems and their role in the theory of the stochastic pump effect (SPE).

  20. Novel BCH Code Design for Mitigation of Phase Noise Induced Cycle Slips in DQPSK Systems

    DEFF Research Database (Denmark)

    Leong, M. Y.; Larsen, Knud J.; Jacobsen, G.

    2014-01-01

    We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbau d DQPSK systems. Performance of BCH codes are investigated in terms of required overhead......We show that by proper code design, phase noise induced cycle slips causing an error floor can be mitigated for 28 Gbau d DQPSK systems. Performance of BCH codes are investigated in terms of required overhead...