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Sample records for learning transient response

  1. Transient Response Analysis of Metropolis Learning in Games

    KAUST Repository

    Jaleel, Hassan

    2017-10-19

    The objective of this work is to provide a qualitative description of the transient properties of stochastic learning dynamics like adaptive play, log-linear learning, and Metropolis learning. The solution concept used in these learning dynamics for potential games is that of stochastic stability, which is based on the stationary distribution of the reversible Markov chain representing the learning process. However, time to converge to a stochastically stable state is exponential in the inverse of noise, which limits the use of stochastic stability as an effective solution concept for these dynamics. We propose a complete solution concept that qualitatively describes the state of the system at all times. The proposed concept is prevalent in control systems literature where a solution to a linear or a non-linear system has two parts, transient response and steady state response. Stochastic stability provides the steady state response of stochastic learning rules. In this work, we study its transient properties. Starting from an initial condition, we identify the subsets of the state space called cycles that have small hitting times and long exit times. Over the long time scales, we provide a description of how the distributions over joint action profiles transition from one cycle to another till it reaches the globally optimal state.

  2. Transient Response Analysis of Metropolis Learning in Games

    KAUST Repository

    Jaleel, Hassan; Shamma, Jeff S.

    2017-01-01

    The objective of this work is to provide a qualitative description of the transient properties of stochastic learning dynamics like adaptive play, log-linear learning, and Metropolis learning. The solution concept used in these learning dynamics for potential games is that of stochastic stability, which is based on the stationary distribution of the reversible Markov chain representing the learning process. However, time to converge to a stochastically stable state is exponential in the inverse of noise, which limits the use of stochastic stability as an effective solution concept for these dynamics. We propose a complete solution concept that qualitatively describes the state of the system at all times. The proposed concept is prevalent in control systems literature where a solution to a linear or a non-linear system has two parts, transient response and steady state response. Stochastic stability provides the steady state response of stochastic learning rules. In this work, we study its transient properties. Starting from an initial condition, we identify the subsets of the state space called cycles that have small hitting times and long exit times. Over the long time scales, we provide a description of how the distributions over joint action profiles transition from one cycle to another till it reaches the globally optimal state.

  3. Transient identification system with noising data and 'don't know' response

    International Nuclear Information System (INIS)

    Mol, Antonio C. de A.; Martinez, Aquilino S.; Schirru, Roberto

    2002-01-01

    In the last years, many different approaches based on neural network (NN) has been proposed for transient identification in nuclear power plants (NPP). Some of them focus the dynamic identification using recurrent neural networks however, they are not able to deal with unrecognized transients. Other kind of solution uses competitive learning in order to allow the 'don't know' response. In this case dynamic, dynamic features are not well represented. This work presents a new approach for neural network based transient identification which allows either dynamic identification and 'don't know'response. Such approach uses two multilayer neural networks trained with backpropagation algorithm. The first one is responsible for the dynamic identification. This NN uses, a short set (in a movable time window) of recent measurements of each variable avoiding the necessity of using starting events. The other one is used to validate the instantaneous identification (from the first net) through the validation of each variable. This net is responsible for allowing the system to provide 'don't know' response. In order to validate the method a NPP transient identification problem comprising 15 postulated accidents, simulated for a pressurized water reactor, was proposed in the validation process it has been considered noising data in other to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know' response. In order to validate the method, a NPP transient identification problem comprising 15 postulated accidents simulated for a pressurized water reactor, was proposed in the validation process it has been considered noising data in order to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know' response. (author)

  4. Implicit learning in transient global amnesia and the role of stress

    Directory of Open Access Journals (Sweden)

    Frauke Nees

    2016-11-01

    Full Text Available Transient global amnesia (TGA is a disorder with reversible anterograde disturbance of explicit memory, frequently preceded by an emotionally or physically stressful event. By using magnetic resonance imaging (MRI following an episode of TGA, small hippocampal lesions have been observed. Hence it has been postulated that the disorder is caused by the stress-related transient inhibition of memory formation in the hippocampus. In experimental studies, stress has been shown to affect both explicit and implicit learning – the latter defined as learning and memory processes that lack conscious awareness of the information acquired. To test the hypothesis that impairment of implicit learning in TGA is present and related to stress, we determined the effect of experimental exposure to stress on hippocampal activation patterns during an implicit learning paradigm in patients who suffered a recent TGA and healthy matched control subjects. We used a hippocampus-dependent aversive learning procedure (context conditioning with the phases habituation, acquisition, and extinction during functional MRI following experimental stress exposure (socially evaluated cold pressor test. After a control procedure, controls showed successful learning during the acquisition phase, indicated by increased valence, arousal and contingency ratings to the paired (CON+ versus the non-paired (CON- conditioned stimulus, and successful extinction of the conditioned responses. Following stress, acquisition was still successful, however extinction was impaired with persistently increased contingency ratings. In contrast, TGA patients showed impairment of conditioned responses and insufficient extinction after the control procedure, indicated by a lack of significant differences between CON+ and CON- for valence and arousal ratings after the acquisition phase and by significantly increased contingency ratings after the extinction. After stress, aversive learning was not successful

  5. A possibilistic approach for transient identification with 'don't know' response capability optimized by genetic algorithm

    International Nuclear Information System (INIS)

    Almeida, Jose Carlos S. de; Schirru, Roberto; Pereira, Claudio M.N.A.; Universidade Federal, Rio de Janeiro, RJ

    2002-01-01

    This work describes a possibilistic approach for transient identification based on the minimum centroids set method, proposed in previous work, optimized by genetic algorithm. The idea behind this method is to split the complex classification problem into small and simple ones, so that the performance in the classification can be increased. In order to accomplish that, a genetic algorithm is used to learn, from realistic simulated data, the optimized time partitions, which the robustness and correctness in the classification are maximized. The use of a possibilistic classification approach propitiates natural and consistent classification rules, leading naturally to a good heuristic to handle the 'don't know 'response, in case of unrecognized transient, which is fairly desirable in transient classification systems where safety is critical. Application of the proposed approach to a nuclear transient indentification problem reveals good capability of the genetic algorithm in learning optimized possibilistic classification rules for efficient diagnosis including 'don't know' response. Obtained results are shown and commented. (author)

  6. Towards addressing transient learning challenges in undergraduate physics: an example from electrostatics

    Science.gov (United States)

    Fredlund, T.; Linder, C.; Airey, J.

    2015-09-01

    In this article we characterize transient learning challenges as learning challenges that arise out of teaching situations rather than conflicts with prior knowledge. We propose that these learning challenges can be identified by paying careful attention to the representations that students produce. Once a transient learning challenge has been identified, teachers can create interventions to address it. By illustration, we argue that an appropriate way to design such interventions is to create variation around the disciplinary-relevant aspects associated with the transient learning challenge.

  7. Instrument response during overpower transients at TREAT

    International Nuclear Information System (INIS)

    Meek, C.C.; Bauer, T.H.; Hill, D.J.; Froehle, P.H.; Klickman, A.E.; Tylka, J.P.; Doerner, R.C.; Wright, A.E.

    1982-01-01

    A program to empirically analyze data residuals or noise to determine instrument response that occurs during in-pile transient tests is out-lined. As an example, thermocouple response in the Mark III loop during a severe overpower transient in TREAT is studied both in frequency space and in real-time. Time intervals studied included both constant power and burst portions of the power transient. Thermocouple time constants were computed. Benefits and limitations of the method are discussed

  8. Stationary and Transient Response Statistics

    DEFF Research Database (Denmark)

    Madsen, Peter Hauge; Krenk, Steen

    1982-01-01

    The covariance functions for the transient response of a linear MDOF-system due to stationary time limited excitation with an arbitrary frequency content are related directly to the covariance functions of the stationary response. For rational spectral density functions closed form expressions fo...

  9. Transients: The regulator's view

    International Nuclear Information System (INIS)

    Sheron, B.W.; Speis, T.P.

    1984-01-01

    This chapter attempts to clarify the basis for the regulator's concerns for transient events. Transients are defined as both anticipated operational occurrences and postulated accidents. Recent operational experience, supplemented by improved probabilistic risk analysis methods, has demonstrated that non-LOCA transient events can be significant contributors to overall risk. Topics considered include lessons learned from events and issues, the regulations governing plant transients, multiple failures, different failure frequencies, operator errors, and public pressure. It is concluded that the formation of Owners Groups and Regulatory Response Groups within the owners groups are positive signs of the industry's concern for safety and responsible dealing with the issues affecting both the US NRC and the industry

  10. Transient identification system with noising data and 'don't know' response; Sistema de identificacao de transientes com inclusao de ruidos e indicacao de eventos desconhecidos

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Antonio C. de A. [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil). Div. de Confiabilidade Humana; Martinez, Aquilino S.; Schirru, Roberto [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear

    2002-07-01

    In the last years, many different approaches based on neural network (NN) has been proposed for transient identification in nuclear power plants (NPP). Some of them focus the dynamic identification using recurrent neural networks however, they are not able to deal with unrecognized transients. Other kind of solution uses competitive learning in order to allow the 'don't know' response. In this case dynamic, dynamic features are not well represented. This work presents a new approach for neural network based transient identification which allows either dynamic identification and 'don't know'response. Such approach uses two multilayer neural networks trained with backpropagation algorithm. The first one is responsible for the dynamic identification. This NN uses, a short set (in a movable time window) of recent measurements of each variable avoiding the necessity of using starting events. The other one is used to validate the instantaneous identification (from the first net) through the validation of each variable. This net is responsible for allowing the system to provide 'don't know' response. In order to validate the method a NPP transient identification problem comprising 15 postulated accidents, simulated for a pressurized water reactor, was proposed in the validation process it has been considered noising data in other to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know' response. In order to validate the method, a NPP transient identification problem comprising 15 postulated accidents simulated for a pressurized water reactor, was proposed in the validation process it has been considered noising data in order to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know

  11. Classifier-ensemble incremental-learning procedure for nuclear transient identification at different operational conditions

    Energy Technology Data Exchange (ETDEWEB)

    Baraldi, Piero, E-mail: piero.baraldi@polimi.i [Dipartimento di Energia - Sezione Ingegneria Nucleare, Politecnico di Milano, via Ponzio 34/3, 20133 Milano (Italy); Razavi-Far, Roozbeh [Dipartimento di Energia - Sezione Ingegneria Nucleare, Politecnico di Milano, via Ponzio 34/3, 20133 Milano (Italy); Zio, Enrico [Dipartimento di Energia - Sezione Ingegneria Nucleare, Politecnico di Milano, via Ponzio 34/3, 20133 Milano (Italy); Ecole Centrale Paris-Supelec, Paris (France)

    2011-04-15

    An important requirement for the practical implementation of empirical diagnostic systems is the capability of classifying transients in all plant operational conditions. The present paper proposes an approach based on an ensemble of classifiers for incrementally learning transients under different operational conditions. New classifiers are added to the ensemble where transients occurring in new operational conditions are not satisfactorily classified. The construction of the ensemble is made by bagging; the base classifier is a supervised Fuzzy C Means (FCM) classifier whose outcomes are combined by majority voting. The incremental learning procedure is applied to the identification of simulated transients in the feedwater system of a Boiling Water Reactor (BWR) under different reactor power levels.

  12. Classifier-ensemble incremental-learning procedure for nuclear transient identification at different operational conditions

    International Nuclear Information System (INIS)

    Baraldi, Piero; Razavi-Far, Roozbeh; Zio, Enrico

    2011-01-01

    An important requirement for the practical implementation of empirical diagnostic systems is the capability of classifying transients in all plant operational conditions. The present paper proposes an approach based on an ensemble of classifiers for incrementally learning transients under different operational conditions. New classifiers are added to the ensemble where transients occurring in new operational conditions are not satisfactorily classified. The construction of the ensemble is made by bagging; the base classifier is a supervised Fuzzy C Means (FCM) classifier whose outcomes are combined by majority voting. The incremental learning procedure is applied to the identification of simulated transients in the feedwater system of a Boiling Water Reactor (BWR) under different reactor power levels.

  13. Modeling of Transient Response of the Wickless Heat Pipes

    International Nuclear Information System (INIS)

    Hussien, A.K.A.

    2013-01-01

    Thermosyphons transient response for startup from ambient temperature to steady state until shutdown conditions, is considered a stringent necessity for applications such as electronic, solar, geothermal and even nuclear reactors safety systems. This typically returns to the need to keep the temperature within certain limits before reaching critical conditions. A simple network model is derived for describing the transient response of closed two-phase thermosyphon (CTPT) at startup and shutdown states. In addition, for predicting the effect of operational characteristics of water/copper closed two-phase thermosyphon such as thermal load, filling ratio, evaporator length, and thermosyphon tube diameter. The thermosyphons operation was considered a thermal network of various components with different thermal resistances and dynamic responses. The network model consists of six sub-models. These models are pure conduction in walls of evaporator, adiabatic and condenser, and convection in evaporator pool, evaporator film, and condenser film. So, an energy balance for each sub-model was done to estimate temperatures, heat transfer coefficients, thermal resistances, time constant, and other thermal characteristics that describe the required transient response of the closed two-phase thermosyphon. Governing equations of the transient thermosyphon behavior can be simplified into a set of first-order linear ordinary differential equations. The Runge-Kutta method can be used to obtain transient thermosyphon temperatures from these equations.

  14. Modelling structural systems for transient response analysis

    International Nuclear Information System (INIS)

    Melosh, R.J.

    1975-01-01

    This paper introduces and reports success of a direct means of determining the time periods in which a structural system behaves as a linear system. Numerical results are based on post fracture transient analyses of simplified nuclear piping systems. Knowledge of the linear response ranges will lead to improved analysis-test correlation and more efficient analyses. It permits direct use of data from physical tests in analysis and simplication of the analytical model and interpretation of its behavior. The paper presents a procedure for deducing linearity based on transient responses. Given the forcing functions and responses of discrete points of the system at various times, the process produces evidence of linearity and quantifies an adequate set of equations of motion. Results of use of the process with linear and nonlinear analyses of piping systems with damping illustrate its success. Results cover the application to data from mathematical system responses. The process is successfull with mathematical models. In loading ranges in which all modes are excited, eight digit accuracy of predictions are obtained from the equations of motion deduced. Small changes (less than 0.01%) in the norm of the transfer matrices are produced by manipulation errors for linear systems yielding evidence that nonlinearity is easily distinguished. Significant changes (greater than five %) are coincident with relatively large norms of the equilibrium correction vector in nonlinear analyses. The paper shows that deducing linearity and, when admissible, quantifying linear equations of motion from transient response data for piping systems can be achieved with accuracy comparable to that of response data

  15. Lithium Battery Transient Response as a Diagnostic Tool

    Science.gov (United States)

    Denisov, E.; Nigmatullin, R.; Evdokimov, Y.; Timergalina, G.

    2018-05-01

    Lithium batteries are currently used as the main energy storage for electronic devices. Progress in the field of portable electronic devices is significantly determined by the improvement of their weight/dimensional characteristics and specific capacity. In addition to the high reliability required of lithium batteries, in some critical applications proper diagnostics are required. Corresponding techniques allow prediction and prevention of operation interruption and avoidance of expensive battery replacement, and also provide additional benefits. Many effective diagnostic methods have been suggested; however, most of them require expensive experimental equipment, as well as interruption or strong perturbation of the operating mode. In the framework of this investigation, a simple diagnostic method based on analysis of transient processes is proposed. The transient response is considered as a reaction to an applied load variation that typically corresponds to normal operating conditions for most real applications. The transient response contains the same information as the impedance characteristic for the system operating in linear mode. Taking into account the large number of publications describing the impedance response associated with diagnostic methods, it can be assumed that the transient response contains a sufficient amount of information for creation of effective diagnostic systems. The proposed experimental installation is based on a controlled load, providing current variation, measuring equipment, and data processing electronics. It is proposed to use the second exponent parameters U 2 and β to estimate the state of charge for secondary lithium batteries. The proposed method improves the accuracy and reliability of a set of quantitative parameters associated with electrochemical energy sources.

  16. Response of dairy cattle to transient voltages and magnetic fields

    International Nuclear Information System (INIS)

    Reinemann, D.J.; Laughlin, N.K.; Stetson, L.E.

    1995-01-01

    Stray voltages in dairy facilities have been studied since the 1970's. Previous research using steady-state ac and dc voltages has defined cow-contact voltage levels which may cause behavior and associated production problems. This research was designed to address concerns over possible effects of transient voltages and magnetic fields on dairy cows. Dairy cows response to transient voltages and magnetic fields was measured. The waveforms of the transient voltages applied were: 5 cycles of 60-Hz ac with a total pulse time of 83 ms, 1 cycle of 60-Hz ac with a total pulse time of 16 ms, and 1 cycle of an ac square wave (spiking positive and negative) of 2-ms duration. Alternating magnetic fields were produced by passing 60-Hz ac fundamental frequency with 2nd and 3rd harmonic and random noise components in metal structures around the cows. The maximum magnetic field associated with this current flow was in excess of 4 G. A wide range of sensitivity to transient voltages was observed among cows. Response levels from 24 cows to each transient exposure were normally distributed. No responses to magnetic fields were observed

  17. Temperature transient response measurement in flowing water

    International Nuclear Information System (INIS)

    Rainbird, J.C.

    1980-01-01

    A specially developed procedure is described for determining the thermal transient response of thermocouples and other temperature transducers when totally immersed in flowing water. The high velocity heat transfer conditions associated with this facility enable thermocouple response times to be predicted in other fluids. These predictions can be confirmed by electrical analogue experiments. (author)

  18. Response of steam-water mixtures to pressure transients

    International Nuclear Information System (INIS)

    Hull, L.M.

    1985-01-01

    During the transition phase of a hypothetical core-disruptive accident in a liquid-metal fast breeder reactor, melting fuel-steel mixtures may begin to boil, resulting in a two-phase mixture of molten reactor fuel and steel vapor. Dispersal of this mixture by pressure transients may prevent recriticality of the fuel material. This paper describes the results of a series of experiments that investigated the response of two-phase mixtures to pressure transients. Simulant fluids (steam/water) were used in a transparent 10.2-cm-dia, 63.5-cm-long acrylic tube. The pressure transient was provided by releasing pressurized nitrogen from a supply tank. The data obtained are in the form of pressure-time records and high-speed movies. The varied parameters are initial void fraction (10% and 40%) and transient pressure magnitude (3.45 and 310 kPa)

  19. Linear population allocation by bistable switches in response to transient stimulation.

    Science.gov (United States)

    Srimani, Jaydeep K; Yao, Guang; Neu, John; Tanouchi, Yu; Lee, Tae Jun; You, Lingchong

    2014-01-01

    Many cellular decision processes, including proliferation, differentiation, and phenotypic switching, are controlled by bistable signaling networks. In response to transient or intermediate input signals, these networks allocate a population fraction to each of two distinct states (e.g. OFF and ON). While extensive studies have been carried out to analyze various bistable networks, they are primarily focused on responses of bistable networks to sustained input signals. In this work, we investigate the response characteristics of bistable networks to transient signals, using both theoretical analysis and numerical simulation. We find that bistable systems exhibit a common property: for input signals with short durations, the fraction of switching cells increases linearly with the signal duration, allowing the population to integrate transient signals to tune its response. We propose that this allocation algorithm can be an optimal response strategy for certain cellular decisions in which excessive switching results in lower population fitness.

  20. Comparison of pressure transient response in intensely and sparsely fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Johns, R.T.

    1989-04-01

    A comprehensive analytical model is presented to study the pressure transient behavior of a naturally fractured reservoir with a continuous matrix block size distribution. Geologically realistic probability density functions of matrix block size are used to represent reservoirs of varying fracture intensity and uniformity. Transient interporosity flow is assumed and interporosity skin is incorporated. Drawdown and interference pressure transient tests are investigated. The results show distinctions in the pressure response from intensely and sparsely fractured reservoirs in the absence of interporosity skin. Also, uniformly and nonuniformly fractured reservoirs exhibit distinct responses, irrespective of the degree of fracture intensity. The pressure response in a nonuniformly fractured reservoir with large block size variability, approaches a nonfractured (homogeneous) reservoir response. Type curves are developed to estimate matrix block size variability and the degree of fracture intensity from drawdown and interference well tests.

  1. Ad Hoc Transient Groups: Instruments for Awareness in Learning Networks

    NARCIS (Netherlands)

    Fetter, Sibren; Rajagopal, Kamakshi; Berlanga, Adriana; Sloep, Peter

    2011-01-01

    Fetter, S., Rajagopal, K., Berlanga, A. J., & Sloep, P. B. (2011). Ad Hoc Transient Groups: Instruments for Awareness in Learning Networks. In W. Reinhardt, T. D. Ullmann, P. Scott, V. Pammer, O. Conlan, & A. J. Berlanga (Eds.), Proceedings of the 1st European Workshop on Awareness and Reflection in

  2. Calculation of Lightning Transient Responses on Wind Turbine Towers

    Directory of Open Access Journals (Sweden)

    Xiaoqing Zhang

    2013-01-01

    Full Text Available An efficient method is proposed in this paper for calculating lightning transient responses on wind turbine towers. In the proposed method, the actual tower body is simplified as a multiconductor grid in the shape of cylinder. A set of formulas are given for evaluating the circuit parameters of the branches in the multiconductor grid. On the basis of the circuit parameters, the multiconductor grid is further converted into an equivalent circuit. The circuit equation is built in frequency-domain to take into account the effect of the frequency-dependent characteristic of the resistances and inductances on lightning transients. The lightning transient responses can be obtained by using the discrete Fourier transform with exponential sampling to take the inverse transform of the frequency-domain solution of the circuit equation. A numerical example has been given for examining the applicability of the proposed method.

  3. Transient Response Dynamic Module Modifications to Include Static and Kinetic Friction Effects

    Science.gov (United States)

    Misel, J. E.; Nenno, S. B.; Takahashi, D.

    1984-01-01

    A methodology that supports forced transient response dynamic solutions when both static and kinetic friction effects are included in a structural system model is described. Modifications that support this type of nonlinear transient response solution are summarized for the transient response dynamics (TRD) NASTRAN module. An overview of specific modifications for the NASTRAN processing subroutines, INITL, TRD1C, and TRD1D, are described with further details regarding inspection of nonlinear input definitions to define the type of nonlinear solution required, along with additional initialization requirements and specific calculation subroutines to successfully solve the transient response problem. The extension of the basic NASTRAN nonlinear methodology is presented through several stages of development to the point where constraint equations and residual flexibility effects are introduced into the finite difference Newmark-Beta recurrsion formulas. Particular emphasis is placed on cost effective solutions for large finite element models such as the Space Shuttle with friction degrees of freedom between the orbiter and payloads mounted in the cargo bay. An alteration to the dynamic finite difference equations of motion is discussed, which allows one to include friction effects at reasonable cost for large structural systems such as the Space Shuttle. Data are presented to indicate the possible impact of transient friction loads to the payload designer for the Space Shuttle. Transient response solution data are also included, which compare solutions without friction forces and those with friction forces for payloads mounted in the Space Shuttle cargo bay. These data indicate that payload components can be sensitive to friction induced loads.

  4. Newborn hearing screening with transient evoked otoacoustic emissions and automatic auditory brainstem response

    Directory of Open Access Journals (Sweden)

    Renata Mota Mamede de Carvallo

    2008-09-01

    Full Text Available Objective: The aim of the present investigation was to check Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem Response tests applied together in regular nurseries and Newborn Intensive Care Units (NICU, as well as to describe and compare the results obtained in both groups. Methods: We tested 150 newborns from regular nurseries and 70 from NICU. Rresults: The newborn hearing screening results using Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem Response tests could be applied to all babies. The “pass” result for the group of babies from the nursery was 94.7% using Transient Evoked Otoacoustic Emissions and 96% using Automatic Auditory Brainstem Response. The newborn intensive care unit group obtained 87.1% on Transient Evoked Otoacoustic Emissions and 80% on the Automatic Auditory Brainstem Response, and there was no statistical difference between the procedures when the groups were evaluated individually. However, comparing the groups, Transient Evoked Otoacoustic Emissions were presented in 94.7% of the nursery babies and in 87.1% in the group from the newborn intensive care unit. Considering the Automatic Auditory Brainstem Response, we found 96 and 87%, respectively. Cconclusions: Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem Response had similar “pass” and “fail” results when the procedures were applied to neonates from the regular nursery, and the combined tests were more precise to detect hearing impairment in the newborn intensive care unit babies.

  5. Cerebrospinal fluid (CSF) transient responses induced by hypercapnia

    International Nuclear Information System (INIS)

    Fisher, M.J.

    1984-01-01

    CSF transient responses to CO 2 inhalation were measured before and after facilitated perfusate flow through subarachnoid spaces of anesthetized cats during ventriculocisternal perfusion with artificial CSF containing 14 C-dextran. Convective mixing of perfusate in subarachnoid spaces was augmented while infusion constant, either by impeding cisternal efflux of perfusate by raising the cisternal outflow cannula (high CSF pressure), or by preventing CSF outflow by clamping the cisternal outflow cannula (stopflow; S-F). CSF transients were also measured before and after systemic administration of phenoxybenzamine (PBZ) in order to evaluate the contribution of sympatho-adrenergic activity to craniospinal CSF redistribution and mixing. Results from high CSF pressure and S-F experiments indicate that unequilibrated CSF contributes significantly to the reduced tracer concentration in CSF volume (Vd) since SCF effluent tracer concentration (Cd) was decreased after subarachnoid facilitated flow. Further, results from S-F studies indicate that at least 50% of Cd is due to craniospinal fluid redistribution, a process which, along with CSF outflow transients, was unaffected by PBZ. Conversely, PBZ administration decreased steady state SCF formation and absorption through alpha-mediated cerebrovascular responses and/or through beta-adrenoceptor inhibition of metabolism of CSF secretory epithelium

  6. Response of the human tympanic membrane to transient acoustic and mechanical stimuli: Preliminary results

    Science.gov (United States)

    Razavi, Payam; Ravicz, Michael E.; Dobrev, Ivo; Cheng, Jeffrey Tao; Furlong, Cosme; Rosowski, John J.

    2016-01-01

    The response of the tympanic membrane (TM) to transient environmental sounds and the contributions of different parts of the TM to middle-ear sound transmission were investigated by measuring the TM response to global transients (acoustic clicks) and to local transients (mechanical impulses) applied to the umbo and various locations on the TM. A lightly-fixed human temporal bone was prepared by removing the ear canal, inner ear, and stapes, leaving the incus, malleus, and TM intact. Motion of nearly the entire TM was measured by a digital holography system with a high speed camera at a rate of 42 000 frames per second, giving a temporal resolution of <24 μs for the duration of the TM response. The entire TM responded nearly instantaneously to acoustic transient stimuli, though the peak displacement and decay time constant varied with location. With local mechanical transients, the TM responded first locally at the site of stimulation, and the response spread approximately symmetrically and circumferentially around the umbo and manubrium. Acoustic and mechanical transients provide distinct and complementary stimuli for the study of TM response. Spatial variations in decay and rate of spread of response imply local variations in TM stiffness, mass, and damping. PMID:26880098

  7. Transient voltage response of a superconducting strip to a supercritical current pulse

    International Nuclear Information System (INIS)

    Attekum, P.M.Th.M. van; Wouters, M.C.H.M.; Wolter, J.; Horstman, R.E.

    1981-01-01

    A superconductor subject to a supercritical current pulse displays a delay time between the onset of the current pulse and the onset of the corresponding voltage response. From the onset of the voltage response it takes a second (transient) time to reach the stationary state. It is shown that the transient time can be explained with inhomogeneities in the strip which give rise to a distribution of delay times. The transient time is thus not related to a characteristic time in the superconductor. For small supercritical currents also heating effects show up. (author)

  8. Machine Learning-based Transient Brokers for Real-time Classification of the LSST Alert Stream

    Science.gov (United States)

    Narayan, Gautham; Zaidi, Tayeb; Soraisam, Monika; ANTARES Collaboration

    2018-01-01

    The number of transient events discovered by wide-field time-domain surveys already far outstrips the combined followup resources of the astronomical community. This number will only increase as we progress towards the commissioning of the Large Synoptic Survey Telescope (LSST), breaking the community's current followup paradigm. Transient brokers - software to sift through, characterize, annotate and prioritize events for followup - will be a critical tool for managing alert streams in the LSST era. Developing the algorithms that underlie the brokers, and obtaining simulated LSST-like datasets prior to LSST commissioning, to train and test these algorithms are formidable, though not insurmountable challenges. The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is a joint project of the National Optical Astronomy Observatory and the Department of Computer Science at the University of Arizona. We have been developing completely automated methods to characterize and classify variable and transient events from their multiband optical photometry. We describe the hierarchical ensemble machine learning algorithm we are developing, and test its performance on sparse, unevenly sampled, heteroskedastic data from various existing observational campaigns, as well as our progress towards incorporating these into a real-time event broker working on live alert streams from time-domain surveys.

  9. Improving the transient response of a bolt-clamped Langevin transducer using a parallel resistor.

    Science.gov (United States)

    Chang, Kuo Tsi

    2003-08-01

    This paper suggests a parallel resistor to reduce DC time constant and DC response time of the transient response, induced immediately after an AC voltage connected to a bolt-clamped Langevin transducer (BLT) is switched off. An equivalent circuit is first expressed. Then, an open-circuit transient response at the terminals induced by initial states is derived and measured, and thus parameters for losses of the BLT device are estimated by DC and AC time constants of the transient response. Moreover, a driving and measuring system is designed to determine transient response and steady-state responses of the BLT device, and a parallel resistor is connected to the BLT device to reduce the DC time constant. Experimental results indicate that the DC time constant greatly exceeds the AC time constant without the parallel resistor, and greatly decreases from 42 to 1 ms by a 100-kOmega parallel resistor.

  10. Learning in shifts of transient attention improves recognition of parts of ambiguous figure-ground displays.

    Science.gov (United States)

    Kristjánsson, Arni

    2009-04-24

    Previously demonstrated learning effects in shifts of transient attention have only been shown to result in beneficial effects upon secondary discrimination tasks and affect landing points of express saccades. Can such learning result in more direct effects upon perception than previously demonstrated? Observers performed a cued Vernier acuity discrimination task where the cue was one of a set of ambiguous figure-ground displays (with a black and white part). The critical measure was whether, if a target appeared consistently within a part of a cue of a certain brightness, this would result in learning effects and whether such learning would then affect recognition of the cue parts. Critically the target always appeared within the same part of each individual cue. Some cues were used in early parts of streaks of repetition of cue-part brightness, and others in latter parts of such streaks. All the observers showed learning in shifts of transient attention, with improved performance the more often the target appeared within the part of the cue of the same brightness. Subsequently the observers judged whether cue-parts had been parts of the cues used on the preceding discrimination task. Recognition of the figure parts, where the target had consistently appeared, improved strongly with increased length of streaks of repetition of cue-part brightness. Learning in shifts of transient attention leads not only to faster attention shifts but to direct effects upon perception, in this case recognition of parts of figure-ground ambiguous cues.

  11. Electromagnetic Transient Response Analysis of DFIG under Cascading Grid Faults Considering Phase Angel Jumps

    DEFF Research Database (Denmark)

    Wang, Yun; Wu, Qiuwei

    2014-01-01

    This paper analysis the electromagnetic transient response characteristics of DFIG under symmetrical and asymmetrical cascading grid fault conditions considering phaseangel jump of grid. On deriving the dynamic equations of the DFIG with considering multiple constraints on balanced and unbalanced...... conditions, phase angel jumps, interval of cascading fault, electromagnetic transient characteristics, the principle of the DFIG response under cascading voltage fault can be extract. The influence of grid angel jump on the transient characteristic of DFIG is analyzed and electromagnetic response...

  12. Transient response of the 'multiple water-bag' plasma

    International Nuclear Information System (INIS)

    Lim Cheeseng

    1989-01-01

    A charge activates impulsively and then decays temporally within a MWB (multiple water-bag)-modelled warm plasma. The transient problem is formulated and asymptotically resolved for large time. The response potential comprises two characteristically distinct quantities W and W N : W is a superposition of spherically expanding, moderately attenuated Kelvin waves contributed by certain points on a subset of dispersion curves; W N is a superposition, associated with two other dispersion curves, of three spherical wavefunctions, one of which incorporates the Fresnel integrals. A transient state feature of the MWB discretization is the partitioning of the response field by growing (fast) fronts, (trailing) slow caustics and a j -surfaces, the fastest among these being an a N- surface (thermal front) which pushes back a quasi-static exterior. Contrary to expectations, there is no response jump across any of those growing partitions. Wavefunctions near the slow caustics possess Airy factors. A rest state ultimately develops behind the slowest slow caustic. An application is made to the fluid plasma. (author)

  13. Transient rheology of stimuli responsive hydrogels: Integrating microrheology and microfluidics

    Science.gov (United States)

    Sato, Jun

    Stimuli-responsive hydrogels have diverse potential applications in the field of drug delivery, tissue engineering, agriculture, cosmetics, gene therapy, and as sensors and actuators due to their unique responsiveness to external signals, such as pH, temperature, and ionic strength. Understanding the responsiveness of hydrogel structure and rheology to these stimuli is essential for designing materials with desirable performance. However, no instrumentation and well-defined methodology are available to characterize the structural and rheological responses to rapid solvent changes. In this thesis, a new microrheology set-up is described, which allows us to quantitatively measure the transient rheological properties and microstructure of a variety of solvent-responsive complex fluids. The device was constructed by integrating particle tracking microrheology and microfluidics and offers unique experimental capabilities for performing solvent-reponse measurements on soft fragile materials without applying external shear forces. Transient analysis methods to quantitatively obtain rheological properties were also constructed, and guidelines for the trade-off between statistical validity and temporal resolution were developed to accurately capture physical transitions. Employing the new device and methodology, we successfully quantified the transient rheological and microstructural responses during gel formation and break-up, and viscosity changes of solvent-responsive complex fluids. The analysis method was expanded for heterogeneous samples, incorporating methods to quantify the microrheology of samples with broad distributions of individual particle dynamics. Transient microrheology measurements of fragile, heterogeneous, self-assembled block copolypeptide hydrogels revealed that solvent exchange via convective mixing and dialysis can lead to significantly different gel properties and that commonly applied sample preparation protocols for the characterization of soft

  14. Response of air cleaning system dampers and blowers to simulated tornado transients

    International Nuclear Information System (INIS)

    Gregory, W.; Idar, E.; Smith, P.; Hensel, E.; Smith, E.

    1985-01-01

    The effects of tornado-like pressure transients upon dampers and blowers in nuclear air cleaning systems were studied. For the dampers pressure drop as a function of flow rate was obtained and an empirical relationship developed. Transient response was examined for several types of dampers, as was structural integrity. Both centrifugal and axi-vane blowers were tested and transient characteristic curves were generated in outrunning and backflow situations. The transient characteristic curves do not necessarily match the quasi-steady characteristic curves

  15. Effect of automatic recirculation flow control on the transient response for Lungmen ABWR plant

    Energy Technology Data Exchange (ETDEWEB)

    Tzang, Y.-C., E-mail: yctzang@aec.gov.t [National Tsing Hua University, Department of Engineering and System Science, Hsinchu 30013, Taiwan (China); Chiang, R.-F.; Ferng, Y.-M.; Pei, B.-S. [National Tsing Hua University, Department of Engineering and System Science, Hsinchu 30013, Taiwan (China)

    2009-12-15

    In this study the automatic mode of the recirculation flow control system (RFCS) for the Lungmen ABWR plant has been modeled and incorporated into the basic RETRAN-02 system model. The integrated system model is then used to perform the analyses for the two transients in which the automatic RFCS is involved. The two transients selected are: (1) one reactor internal pump (RIP) trip, and (2) loss of feedwater heating. In general, the integrated system model can predict well the response of key system parameters, including neutron flux, steam dome pressure, heat flux, RIP flow, core inlet flow, feedwater flow, steam flow, and reactor water level. The transients are also analyzed for manual RFCS case, between the automatic RFCS and the manual RFCS cases, comparisons of the transient response for the key system parameter show that the difference of transient response can be clearly identified. Also, the results show that the DELTACPR (delta critical power ratio) for the transients analyzed may not be less limiting for the automatic RFCS case under certain combination of control system settings.

  16. Electrical and optical response of a laser diode to transient ionizing radiation

    International Nuclear Information System (INIS)

    Baggio, J.; Brisset, C.; Sommer, J.L.; D'hose, C.; Lalande, P.; Leray, J.L.; Musseau, O.

    1996-01-01

    The authors have studied transient irradiation effects on the optical and electrical responses of a laser diode. The influence of dose rate, ranging from 10 9 to 10 12 rad(Si)/s, has been investigated through a complete experimental study. Dose rate vulnerability of the laser diode has been observed. Electrical and optical transient responses are determined by the dose rate, the diode structure, and its operating point

  17. Progressive practice promotes motor learning and repeated transient increases in corticospinal excitability across multiple days

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Madsen, Mads Alexander Just; Bojsen-Møller, Emil

    2018-01-01

    Background: A session of motor skill learning is accompanied by transient increases in corticospinal excitability (CSE), which are thought to reflect acute changes in neuronal connectivity associated with improvements in sensorimotor performance. Factors influencing changes in excitability...... and motor skill with continued practice remain however to be elucidated. Objective/Hypothesis: Here we investigate the hypothesis that progressive motor practice during consecutive days can induce repeated transient increases in corticospinal excitability and promote motor skill learning. Methods: Changes...... in motor performance and CSE were assessed during 4 consecutive days of skill learning and 8 days after the last practice session. CSE was assessed as area under recruitment curves (RC) using transcranial magnetic stimulation (TMS). Two groups of participants (n = 12) practiced a visuomotor tracking...

  18. Dose-dependent suppression by ethanol of transient auditory 40-Hz response.

    Science.gov (United States)

    Jääskeläinen, I P; Hirvonen, J; Saher, M; Pekkonen, E; Sillanaukee, P; Näätänen, R; Tiitinen, H

    2000-02-01

    Acute alcohol (ethanol) challenge is known to induce various cognitive disturbances, yet the neural basis of the effect is poorly known. The auditory transient evoked gamma-band (40-Hz) oscillatory responses have been suggested to be associated with various perceptual and cognitive functions in humans; however, alcohol effects on auditory 40-Hz responses have not been investigated to date. The objective of the study was to test the dose-related impact of alcohol on auditory transient evoked 40-Hz responses during a selective-attention task. Ten healthy social drinkers ingested, in four separate sessions, 0.00, 0. 25, 0.50, or 0.75 g/kg of 10% (v/v) alcohol solution. The order of the sessions was randomized and a double-blind procedure was employed. During a selective attention task, 300-Hz standard and 330-Hz deviant tones were presented to the left ear, and 1000-Hz standards and 1100-Hz deviants to the right ear of the subjects (P=0. 425 for each standard, P=0.075 for each deviant). The subjects attended to a designated ear, and were to detect the deviants therein while ignoring tones to the other ear. The auditory transient evoked 40-Hz responses elicited by both the attended and unattended standard tones were significantly suppressed by the 0.50 and 0.75 g/kg alcohol doses. Alcohol suppresses auditory transient evoked 40-Hz oscillations already with moderate blood alcohol concentrations. Given the putative role of gamma-band oscillations in cognition, this finding could be associated with certain alcohol-induced cognitive deficits.

  19. Atmospheric CO2 and climate: Importance of the transient response

    International Nuclear Information System (INIS)

    Schneider, S.H.; Thompson, S.L.

    1981-01-01

    Preliminary studies suggest that the thermal inertia of the upper layers of the oceans, combined with vertical mixing of deeper oceanic waters, could delay the response of the globally averaged surface temperature to an increasing atmospheric CO 2 concentration by a decade or so relative to equilibrium calculations. This study extends the global analysis of the transient response to zonal averages, using a hierarchy of simple energy balance models and vertical mixing assumptions for water exchange between upper and deeper oceanic layers. It is found that because of the latitudinal dependence of both thermal inertia and radiative and dynamic energy exchange mechanisms, the approach toward equilibrium of the surface temperature of various regions of the earth will be significantly different from the global average approach. This suggests that the actual time evolution of the horizontal surface temperature gradients--and any associated regional climatic anomalies-may well be significantly different from that suggested by equilibrium climatic modeling simulations (or those computed with a highly unrealistic geographic distribution of ocean thermal capacity). Also, the transient response as a function of latitude is significantly different between globally equivalent CO 2 and solar constant focusing runs. It is suggested that the nature of the transient response is a major uncertainty in characterizing the CO 2 problem and that study of this topic should become a major priority for future research. An appendix puts this issue in the context of the overall CO 2 problem

  20. Genetic and neural approaches to nuclear transient identification

    International Nuclear Information System (INIS)

    Almeida, Jose Carlos Soares de; Mol, Antonio Carlos de Abreu; Pereira, Claudio Marcio Nascimento Abreu; Lapa, Celso Marcelo Franklin

    2005-01-01

    This work presents two approaches for pattern recognition to the same set of reactor signals. The first one describes a possibilistic approach optimized by genetic algorithm. The use of a possibilistic classification provides a natural and consistent classification rules, leading naturally to a good heuristic to handle the 'don't know' response, in case of unrecognized transient, which is fairly desirable in transient classification systems where safety is critical, since wrong or not reliable classifications can be catastrophic. Application of the proposed approach to a nuclear transient identification problem reveals good capability of the genetic algorithm in learning optimized possibilistic classification rules for efficient diagnosis including 'don't know' response. The second one uses two multilayer neural networks (NN). The first NN is responsible for the dynamic identification. This NN uses, as input, a short set (in a moving time window) of recent measurements of each variable avoiding the necessity of using starting events. The second NN is used to validate the instantaneous identification (from the first net) through the validation of each variable. This net is responsible for allowing the system to provide a 'don't know' response. In order to validate both methods, a Nuclear Power Plant (NPP) transient identification problem comprising postulated accidents, simulated for a pressurized water reactor, was proposed in the validation process it has been considered noisy data in order to evaluate the method robustness. Obtained results reveal the ability of the methods in dealing with both dynamic identification of transients and correct 'don't know' response. (author)

  1. Nonstationary Transient Vibroacoustic Response of a Beam Structure

    Science.gov (United States)

    Caimi, R. E.; Margasahayam, R. N.; Nayfeh, Jamal F.

    1997-01-01

    This study consists of an investigation into the nonstationary transient response of the Verification Test Article (VETA) when subjected to random acoustic excitation. The goal is to assess excitation models that can be used in the design of structures and equipment when knowledge of the structure and the excitation is limited. The VETA is an instrumented cantilever beam that was exposed to acoustic loading during five Space Shuttle launches. The VETA analytical structural model response is estimated using the direct averaged power spectral density and the normalized pressure spectra methods. The estimated responses are compared to the measured response of the VETA. These comparisons are discussed with a focus on prediction conservatism and current design practice.

  2. Analysis of piping response to thermal and operational transients

    International Nuclear Information System (INIS)

    Wang, C.Y.

    1987-01-01

    The reactor piping system is an extremely complex three-dimensional structure. Maintaining its structural integrity is essential to the safe operation of the reactor and the steam-supply system. In the safety analysis, various transient loads can be imposed on the piping which may cause plastic deformation and possible damage to the system, including those generated from hydrodynamic wave propagations, thermal and operational transients, as well as the seismic events. At Argonne National Laboratory (ANL), a three-dimensional (3-D) piping code, SHAPS, aimed for short-duration transients due to wave propagation, has been developed. Since 1984, the development work has been shifted to the long-duration accidents originating from the thermal and operational transient. As a result, a new version of the code, SHAPS-2, is being established. This paper describes many features related to this later development. To analyze piping response generated from thermal and operational transients, a 3-D implicit finite element algorithm has been developed for calculating the hoop, flexural, axial, and torsional deformations induced by the thermomechanical loads. The analysis appropriately accounts for stresses arising from the temperature dependence of the elastic material properties, the thermal expansion of the materials, and the changes in the temperature-dependent yield surface. Thermal softening, failure, strain rate, creep, and stress ratching can also be considered

  3. Benzodiazepine temazepam suppresses the transient auditory 40-Hz response amplitude in humans.

    Science.gov (United States)

    Jääskeläinen, I P; Hirvonen, J; Saher, M; Pekkonen, E; Sillanaukee, P; Näätänen, R; Tiitinen, H

    1999-06-18

    To discern the role of the GABA(A) receptors in the generation and attentive modulation of the transient auditory 40-Hz response, the effects of the benzodiazepine temazepam (10 mg) were studied in 10 healthy social drinkers, using a double-blind placebo-controlled design. Three hundred Hertz standard and 330 Hz rare deviant tones were presented to the left, and 1000 Hz standards and 1100 Hz deviants to the right ear of the subjects. Subjects attended to a designated ear and were to detect deviants therein while ignoring tones to the other. Temazepam significantly suppressed the amplitude of the 40-Hz response, the effect being equal for attended and non-attended tone responses. This suggests involvement of GABA(A) receptors in transient auditory 40-Hz response generation, however, not in the attentive modulation of the 40-Hz response.

  4. Transient cardio-respiratory responses to visually induced tilt illusions

    Science.gov (United States)

    Wood, S. J.; Ramsdell, C. D.; Mullen, T. J.; Oman, C. M.; Harm, D. L.; Paloski, W. H.

    2000-01-01

    Although the orthostatic cardio-respiratory response is primarily mediated by the baroreflex, studies have shown that vestibular cues also contribute in both humans and animals. We have demonstrated a visually mediated response to illusory tilt in some human subjects. Blood pressure, heart and respiration rate, and lung volume were monitored in 16 supine human subjects during two types of visual stimulation, and compared with responses to real passive whole body tilt from supine to head 80 degrees upright. Visual tilt stimuli consisted of either a static scene from an overhead mirror or constant velocity scene motion along different body axes generated by an ultra-wide dome projection system. Visual vertical cues were initially aligned with the longitudinal body axis. Subjective tilt and self-motion were reported verbally. Although significant changes in cardio-respiratory parameters to illusory tilts could not be demonstrated for the entire group, several subjects showed significant transient decreases in mean blood pressure resembling their initial response to passive head-up tilt. Changes in pulse pressure and a slight elevation in heart rate were noted. These transient responses are consistent with the hypothesis that visual-vestibular input contributes to the initial cardiovascular adjustment to a change in posture in humans. On average the static scene elicited perceived tilt without rotation. Dome scene pitch and yaw elicited perceived tilt and rotation, and dome roll motion elicited perceived rotation without tilt. A significant correlation between the magnitude of physiological and subjective reports could not be demonstrated.

  5. Real-Time Gas Identification by Analyzing the Transient Response of Capillary-Attached Conductive Gas Sensor

    Directory of Open Access Journals (Sweden)

    Behzad Bahraminejad

    2010-05-01

    Full Text Available In this study, the ability of the Capillary-attached conductive gas sensor (CGS in real-time gas identification was investigated. The structure of the prototype fabricated CGS is presented. Portions were selected from the beginning of the CGS transient response including the first 11 samples to the first 100 samples. Different feature extraction and classification methods were applied on the selected portions. Validation of methods was evaluated to study the ability of an early portion of the CGS transient response in target gas (TG identification. Experimental results proved that applying extracted features from an early part of the CGS transient response along with a classifier can distinguish short-chain alcohols from each other perfectly. Decreasing time of exposition in the interaction between target gas and sensing element improved the reliability of the sensor. Classification rate was also improved and time of identification was decreased. Moreover, the results indicated the optimum interval of the early transient response of the CGS for selecting portions to achieve the best classification rates.

  6. Improved Transient Response Estimations in Predicting 40 Hz Auditory Steady-State Response Using Deconvolution Methods

    Directory of Open Access Journals (Sweden)

    Xiaodan Tan

    2017-12-01

    Full Text Available The auditory steady-state response (ASSR is one of the main approaches in clinic for health screening and frequency-specific hearing assessment. However, its generation mechanism is still of much controversy. In the present study, the linear superposition hypothesis for the generation of ASSRs was investigated by comparing the relationships between the classical 40 Hz ASSR and three synthetic ASSRs obtained from three different templates for transient auditory evoked potential (AEP. These three AEPs are the traditional AEP at 5 Hz and two 40 Hz AEPs derived from two deconvolution algorithms using stimulus sequences, i.e., continuous loop averaging deconvolution (CLAD and multi-rate steady-state average deconvolution (MSAD. CLAD requires irregular inter-stimulus intervals (ISIs in the sequence while MSAD uses the same ISIs but evenly-spaced stimulus sequences which mimics the classical 40 Hz ASSR. It has been reported that these reconstructed templates show similar patterns but significant difference in morphology and distinct frequency characteristics in synthetic ASSRs. The prediction accuracies of ASSR using these templates show significant differences (p < 0.05 in 45.95, 36.28, and 10.84% of total time points within four cycles of ASSR for the traditional, CLAD, and MSAD templates, respectively, as compared with the classical 40 Hz ASSR, and the ASSR synthesized from the MSAD transient AEP suggests the best similarity. And such a similarity is also demonstrated at individuals only in MSAD showing no statistically significant difference (Hotelling's T2 test, T2 = 6.96, F = 0.80, p = 0.592 as compared with the classical 40 Hz ASSR. The present results indicate that both stimulation rate and sequencing factor (ISI variation affect transient AEP reconstructions from steady-state stimulation protocols. Furthermore, both auditory brainstem response (ABR and middle latency response (MLR are observed in contributing to the composition of ASSR but

  7. A neural model for transient identification in dynamic processes with 'don't know' response

    International Nuclear Information System (INIS)

    Mol, Antonio C. de A.; Martinez, Aquilino S.; Schirru, Roberto

    2003-01-01

    This work presents an approach for neural network based transient identification which allows either dynamic identification or a 'don't know' response. The approach uses two 'jump' multilayer neural networks (NN) trained with the backpropagation algorithm. The 'jump' network is used because it is useful to dealing with very complex patterns, which is the case of the space of the state variables during some abnormal events. The first one is responsible for the dynamic identification. This NN uses, as input, a short set (in a moving time window) of recent measurements of each variable avoiding the necessity of using starting events. The other one is used to validate the instantaneous identification (from the first net) through the validation of each variable. This net is responsible for allowing the system to provide a 'don't know' response. In order to validate the method, a Nuclear Power Plant (NPP) transient identification problem comprising 15 postulated accidents, simulated for a pressurized water reactor (PWR), was proposed in the validation process it has been considered noisy data in order to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know' response. Another important point studied in this work is that the system has shown to be independent of a trigger signal which indicates the beginning of the transient, thus making it robust in relation to this limitation

  8. Reducing Conservatism of Analytic Transient Response Bounds via Shaping Filters

    Science.gov (United States)

    Kwan, Aiyueh; Bedrossian, Nazareth; Jan, Jiann-Woei; Grigoriadis, Karolos; Hua, Tuyen (Technical Monitor)

    1999-01-01

    Recent results show that the peak transient response of a linear system to bounded energy inputs can be computed using the energy-to-peak gain of the system. However, analytically computed peak response bound can be conservative for a class of class bounded energy signals, specifically pulse trains generated from jet firings encountered in space vehicles. In this paper, shaping filters are proposed as a Methodology to reduce the conservatism of peak response analytic bounds. This Methodology was applied to a realistic Space Station assembly operation subject to jet firings. The results indicate that shaping filters indeed reduce the predicted peak response bounds.

  9. Optimized Extreme Learning Machine for Power System Transient Stability Prediction Using Synchrophasors

    Directory of Open Access Journals (Sweden)

    Yanjun Zhang

    2015-01-01

    Full Text Available A new optimized extreme learning machine- (ELM- based method for power system transient stability prediction (TSP using synchrophasors is presented in this paper. First, the input features symbolizing the transient stability of power systems are extracted from synchronized measurements. Then, an ELM classifier is employed to build the TSP model. And finally, the optimal parameters of the model are optimized by using the improved particle swarm optimization (IPSO algorithm. The novelty of the proposal is in the fact that it improves the prediction performance of the ELM-based TSP model by using IPSO to optimize the parameters of the model with synchrophasors. And finally, based on the test results on both IEEE 39-bus system and a large-scale real power system, the correctness and validity of the presented approach are verified.

  10. Learning from anticipated and abnormal plant transients

    International Nuclear Information System (INIS)

    Varnado, B.

    1983-01-01

    A report is given of the American Nuclear Society topical meeting on Anticipated and Abnormal Transients in Light Water Reactors held in Jackson, Wyoming in September 1983. Industry involvement in the evaluation of operating experience, human error contributions, transient management, thermal hydraulic modelling, the role of probabilistic risk assessment and the cost of transient incidents are discussed. (U.K.)

  11. Transient temperature response of in-vessel components due to pulsed operation in tokamak fusion experimental reactor (FER)

    International Nuclear Information System (INIS)

    Minato, Akio; Tone, Tatsuzo

    1985-12-01

    A transient temperature response of the in-vessel components (first wall, blanket, divertor/limiter and shielding) surrounding plasma in Tokamak Fusion Experimental Reactor (FER) has been analysed. Transient heat load during start up/shut down and pulsed operation cycles causes the transient temperature response in those components. The fatigue lifetime of those components significantly depends upon the resulting cyclic thermal stress. The burn time affects the temperature control in the solid breeder (Li 2 O) and also affects the thermo-mechanical design of the blanket and shielding which are constructed with thick structure. In this report, results of the transient temperature response obtained by the heat transfer and conduction analyses for various pulsed operation scenarios (start up, shut down, burn and dwell times) have been investigated in view of thermo-mechanical design of the in-vessel components. (author)

  12. Abnormal autonomic cardiac response to transient hypoxia in sickle cell anemia

    International Nuclear Information System (INIS)

    Sangkatumvong, S; Khoo, M C K; Coates, T D

    2008-01-01

    The objective of this study was to non-invasively assess cardiac autonomic control in subjects with sickle cell anemia (SCA) by tracking the changes in heart rate variability (HRV) that occur following brief exposure to a hypoxic stimulus. Five African–American SCA patients and seven healthy control subjects were recruited to participate in this study. Each subject was exposed to a controlled hypoxic stimulus consisting of five breaths of nitrogen. Time-varying spectral analysis of HRV was applied to estimate the cardiac autonomic response to the transient episode of hypoxia. The confounding effects of changes in respiration on the HRV spectral indices were reduced by using a computational model. A significant decrease in the parameters related to parasympathetic control was detected in the post-hypoxic responses of the SCA subjects relative to normal controls. The spectral index related to sympathetic activity, on the other hand, showed a tendency to increase the following hypoxic stimulation, but the change was not significant. This study suggests that there is some degree of cardiovascular autonomic dysfunction in SCA that is revealed by the response to transient hypoxia

  13. Newborn hearing screening with transient evoked otoacoustic emissions and automatic auditory brainstem response

    OpenAIRE

    Renata Mota Mamede de Carvallo; Carla Gentile Matas; Isabela de Souza Jardim

    2008-01-01

    Objective: The aim of the present investigation was to check Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem Response tests applied together in regular nurseries and Newborn Intensive Care Units (NICU), as well as to describe and compare the results obtained in both groups. Methods: We tested 150 newborns from regular nurseries and 70 from NICU. Rresults: The newborn hearing screening results using Transient Evoked Otoacoustic Emissions and Automatic Auditory Brainstem...

  14. Transient Response of Thin Wire above a Layered Half-Space Using TDIE/FDTD Hybrid Method

    Directory of Open Access Journals (Sweden)

    Bing Wei

    2012-01-01

    Full Text Available The TDIE/FDTD hybrid method is applied to calculate the transient responses of thin wire above a lossy layered half-space. The time-domain reflection of the layered half space is computed by one-dimensional modified FDTD method. Then, transient response of thin wire induced by two excitation sources (the incident wave and reflected wave is calculated by TDIE method. Finally numerical results are given to illustrate the feasibility and high efficiency of the presented scheme.

  15. Transient response of nonideal ion-selective microchannel-nanochannel devices

    Science.gov (United States)

    Leibowitz, Neta; Schiffbauer, Jarrod; Park, Sinwook; Yossifon, Gilad

    2018-04-01

    We report evidence of variation in ion selectivity of a fabricated microchannel-nanochannel device resulting in the appearance of a distinct local maximum in the overlimiting chronopotentiometric response. In this system consisting of shallow microchannels joined by a nanochannel, viscous shear at the microchannel walls suppresses the electro-osmotic instability and prevents any associated contribution to the nonmonotonic response. Thus, this response is primarily electrodiffusive. Numerical simulations indicate that concentration polarization develops not only within the microchannel but also within the nanochannel itself, with a local voltage maximum in the chronopotentiometric response correlated with interfacial depletion and having the classic i-2 Sands time dependence. Furthermore, the occurrence of the local maxima is correlated with the change in selectivity due to internal concentration polarization. Understanding the transient nonideal permselective response is essential for obtaining fundamental insight and for optimizing efficient operation of practical fabricated nanofluidic and membrane devices.

  16. The transient response of a quantum wave to an instantaneous potential step switching

    Energy Technology Data Exchange (ETDEWEB)

    Delgado, F [Departamento de Quimica-Fisica, Universidad del Pais Vasco, Apdo 644, 48080 Bilbao (Spain); Cruz, H [Departamento de Fisica Basica, Universidad de La Laguna (Spain); Muga, J G [Departamento de Quimica-Fisica, Universidad del Pais Vasco, Apdo 644, 48080 Bilbao (Spain)

    2002-12-06

    The transient response of a stationary state of a quantum particle in a step potential to an instantaneous change in the step height (a simplified model for a sudden bias switch in an electronic semiconductor device) is solved exactly by means of a semianalytical expression. The characteristic times for the transient process up to the new stationary state are identified. A comparison is made between the exact results and an approximate method.

  17. System transient response to loss of off-site power

    International Nuclear Information System (INIS)

    Sozer, A.

    1990-01-01

    A simultaneous trip of the reactor, main circulation pumps, secondary coolant pumps, and pressurizer pump due to loss of off-site power at the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory (ORNL) has been analyzed to estimate available safety margin. A computer model based on the Modular Modeling System code has been used to calculate the transient response of the system. The reactor depressurizes from 482.7 psia down to about 23 psia in about 50 seconds and remains stable thereafter. Available safety margin has been estimated in terms of the incipient boiling heat flux ratio. It is a conservative estimate due to assumed less than available primary and secondary flows and higher than normal depressurization rate. The ratio indicates no incipient boiling conditions at the hot spot. No potential damage to the fuel is likely to occur during this transient. 2 refs., 6 figs

  18. Surge protective device response to steep front transient in low voltage circuit

    Energy Technology Data Exchange (ETDEWEB)

    Marcuz, J.; Binczak, S.; Bilbault, J.M. [Universite de Bourgogne, Dijon (France)], Emails: jerome.marcuz@ laposte.net, stbinc@u-bourgogne.fr, bilbault@u-bourgogne.fr; Girard, F. [ADEE Electronic, Pont de Pany (France)

    2007-07-01

    Surge propagation on cables of electrical or data lines leads to a major protection problem as the number of equipment based on solid-state circuits or microprocessors increases. Sub-microsecond components of real surge waveform has to be taken into account for a proper protection even in the case of surges caused by indirect lightning effects. The response of a model of transient voltage suppressor diode based surge protection device (SPD) to fast front transient is analytically studied, then compared to simulations, including the lines connected to the SPD and to the protected equipment. (author)

  19. Operational transients: A regional administrator's view

    International Nuclear Information System (INIS)

    Collins, J.T.; Johnson, E.H.

    1984-01-01

    This chapter discusses the response of the regional US NRC to operational transients. Three of the major lessons learned from the Three Mile Island-2 accident are reviewed. The need to consider the more probable events of lesser consequences in addition to the significant events is now realized. The importance of the operator in the course of an operational event has been recognized. Three Mile Island also pointed out the many design and hardware deficiencies. Topics considered include the industry capability to meet the challenge of operational transients, the region's capability, and the capability of the utility. It is recommended that technical drills be developed, that plant-specific technical competence be improved, that operator training and education be improved, and that the attitude changes on the part of utilities and the nuclear industry in general be accelerated

  20. Transient response of nonlinear polymer networks: A kinetic theory

    Science.gov (United States)

    Vernerey, Franck J.

    2018-06-01

    Dynamic networks are found in a majority of natural materials, but also in engineering materials, such as entangled polymers and physically cross-linked gels. Owing to their transient bond dynamics, these networks display a rich class of behaviors, from elasticity, rheology, self-healing, or growth. Although classical theories in rheology and mechanics have enabled us to characterize these materials, there is still a gap in our understanding on how individuals (i.e., the mechanics of each building blocks and its connection with others) affect the emerging response of the network. In this work, we introduce an alternative way to think about these networks from a statistical point of view. More specifically, a network is seen as a collection of individual polymer chains connected by weak bonds that can associate and dissociate over time. From the knowledge of these individual chains (elasticity, transient attachment, and detachment events), we construct a statistical description of the population and derive an evolution equation of their distribution based on applied deformation and their local interactions. We specifically concentrate on nonlinear elastic response that follows from the strain stiffening response of individual chains of finite size. Upon appropriate averaging operations and using a mean field approximation, we show that the distribution can be replaced by a so-called chain distribution tensor that is used to determine important macroscopic measures such as stress, energy storage and dissipation in the network. Prediction of the kinetic theory are then explored against known experimental measurement of polymer responses under uniaxial loading. It is found that even under the simplest assumptions of force-independent chain kinetics, the model is able to reproduce complex time-dependent behaviors of rubber and self-healing supramolecular polymers.

  1. Inhibition of P2X7 receptor ameliorates transient global cerebral ischemia/reperfusion injury via modulating inflammatory responses in the rat hippocampus

    Directory of Open Access Journals (Sweden)

    Chu Ketan

    2012-04-01

    Full Text Available Abstract Background Neuroinflammation plays an important role in cerebral ischemia/reperfusion (I/R injury. The P2X7 receptor (P2X7R has been reported to be involved in the inflammatory response of many central nervous system diseases. However, the role of P2X7Rs in transient global cerebral I/R injury remains unclear. The purpose of this study is to determine the effects of inhibiting the P2X7R in a rat model of transient global cerebral I/R injury, and then to explore the association between the P2X7R and neuroinflammation after transient global cerebral I/R injury. Methods Immediately after infusion with the P2X7R antagonists Brilliant blue G (BBG, adenosine 5′-triphosphate-2′,3′-dialdehyde (OxATP or A-438079, 20 minutes of transient global cerebral I/R was induced using the four-vessel occlusion (4-VO method in rats. Survival rate was calculated, neuronal death in the hippocampal CA1 region was observed using H & E staining, and DNA cleavage was observed by deoxynucleotidyl transferase-mediated UTP nick end labeling TUNEL. In addition, behavioral deficits were measured using the Morris water maze, and RT-PCR and immunohistochemical staining were performed to measure the expression of IL-1β, TNF-α and IL-6, and to identify activated microglia and astrocytes. Results The P2X7R antagonists protected against transient global cerebral I/R injury in a dosage-dependent manner. A high dosage of BBG (10 μg and A-0438079 (3 μg, and a low dosage of OxATP (1 μg significantly increased survival rates, reduced I/R-induced learning memory deficit, and reduced I/R-induced neuronal death, DNA cleavage, and glial activation and inflammatory cytokine overexpression in the hippocampus. Conclusions Our study indicates that inhibiting P2X7Rs protects against transient global cerebral I/R injury by reducing the I/R-induced inflammatory response, which suggests inhibition of P2X7Rs may be a promising therapeutic strategy for clinical treatment of

  2. A numerical algorithm to evaluate the transient response for a synchronous scanning streak camera using a time-domain Baum–Liu–Tesche equation

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Chengquan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); Tian, Jinshou [Xi' an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi' an 710119 (China); Wu, Shengli, E-mail: slwu@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China); He, Jiai [School of Computer and Communication, Lanzhou University of Technology, Lanzhou, Gansu 730050 (China); Liu, Zhen [Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xi' an Jiaotong University, Xi’an 710049 (China)

    2016-10-01

    The transient response is of great influence on the electromagnetic compatibility of synchronous scanning streak cameras (SSSCs). In this paper we propose a numerical method to evaluate the transient response of the scanning deflection plate (SDP). First, we created a simplified circuit model for the SDP used in an SSSC, and then derived the Baum–Liu–Tesche (BLT) equation in the frequency domain. From the frequency-domain BLT equation, its transient counterpart was derived. These parameters, together with the transient-BLT equation, were used to compute the transient load voltage and load current, and then a novel numerical method to fulfill the continuity equation was used. Several numerical simulations were conducted to verify this proposed method. The computed results were then compared with transient responses obtained by a frequency-domain/fast Fourier transform (FFT) method, and the accordance was excellent for highly conducting cables. The benefit of deriving the BLT equation in the time domain is that it may be used with slight modifications to calculate the transient response and the error can be controlled by a computer program. The result showed that the transient voltage was up to 1000 V and the transient current was approximately 10 A, so some protective measures should be taken to improve the electromagnetic compatibility.

  3. A numerical algorithm to evaluate the transient response for a synchronous scanning streak camera using a time-domain Baum–Liu–Tesche equation

    International Nuclear Information System (INIS)

    Pei, Chengquan; Tian, Jinshou; Wu, Shengli; He, Jiai; Liu, Zhen

    2016-01-01

    The transient response is of great influence on the electromagnetic compatibility of synchronous scanning streak cameras (SSSCs). In this paper we propose a numerical method to evaluate the transient response of the scanning deflection plate (SDP). First, we created a simplified circuit model for the SDP used in an SSSC, and then derived the Baum–Liu–Tesche (BLT) equation in the frequency domain. From the frequency-domain BLT equation, its transient counterpart was derived. These parameters, together with the transient-BLT equation, were used to compute the transient load voltage and load current, and then a novel numerical method to fulfill the continuity equation was used. Several numerical simulations were conducted to verify this proposed method. The computed results were then compared with transient responses obtained by a frequency-domain/fast Fourier transform (FFT) method, and the accordance was excellent for highly conducting cables. The benefit of deriving the BLT equation in the time domain is that it may be used with slight modifications to calculate the transient response and the error can be controlled by a computer program. The result showed that the transient voltage was up to 1000 V and the transient current was approximately 10 A, so some protective measures should be taken to improve the electromagnetic compatibility.

  4. The effects of air stoichiometry and air excess ratio on the transient response of a PEMFC under load change conditions

    International Nuclear Information System (INIS)

    Kim, Bosung; Cha, Dowon; Kim, Yongchan

    2015-01-01

    Highlights: • Effects of controlling parameters on the transient response of a PEMFC are studied. • The transient response is measured by varying air stoichiometry and air excess ratio. • Voltage drop, undershoot, and voltage fluctuation are analyzed under the load change. • Optimal air stoichiometry and air excess ratio are suggested for stable operation. - Abstract: The transient response of a proton exchange membrane fuel cell (PEMFC) is an important issue for transportation applications. The objective of this study is to investigate the effects of operating and controlling parameters on the transient response of a PEMFC for achieving more stable cell performance under load change conditions. The transient response of a PEMFC was measured and analyzed by varying air stoichiometry, air humidity, and air excess ratio (AER). The optimal air stoichiometry and AER were determined to minimize the voltage drop, undershoot, and voltage fluctuation under the load change, while maintaining high cell performance. Based on the present data, the optimal air stoichiometry was determined to be between 2.0 and 2.5, and the optimal AER was suggested to be between 1.65 and 2.0

  5. Analysis of transient thermal response in the outlet plenum of an LMFBR

    International Nuclear Information System (INIS)

    Yang, J.W.

    1976-05-01

    A two-zone mixing model based on the lumped-parameter approach was developed for the analysis of transient thermal response in the upper outlet plenum of an LMFBR. The one-dimensional turbulent jet flow equations were solved to determine the maximum penetration of the core flow. The maximum penetration is used as the criterion for dividing the sodium region into two mixing zones. The lumped-parameter model considers the transient sodium temperature affected by the thermal expansion of sodium, heat transfer with cover gas, heat capacity of different sections of metal and the addition of bypass flow into the plenum. Numerical calculations were performed for two cases. The first case corresponds to a normal scram followed by flow coast-down. The second case represents the double-ended pipe rupture at the inlet of cold leg followed by reactor scram. The results indicate that effects of flow stratification, chimney height, metal heat capacity and bypass flow are important for transient sodium temperature calculation. Thermal expansion of sodium and heat transfer with the cover gas does not play any significant role on sodium temperature. This two-zone mixing model will be a part of the thermohydraulic transient code SSC

  6. Fuel pin response to an overpower transient in an LMFBR

    International Nuclear Information System (INIS)

    Grosberg, A.J.; Head, J.L.

    1979-01-01

    This paper describes a method by which the ability of a whole-core code accurately to predict the time and location of the first fuel pin failures may be tested. The method involves the use of a relatively simple whole-core code to 'drive' a sophisticated fuel pin code, which is far too complex to be used within a whole-core code but which is potentially capable of modelling reliably the response of an individual fuel pin. The method cannot follow accurately the subsequent course of the transient because the simple whole-core code does not model the reactivity effects of events which may follow pin failure. The codes used were the simple whole-core code FUTURE and the fuel pin behaviour code FRUMP. The paper describes an application of the method to analyse a hypothetical LMFBR accident in which the control rods were assumed to be driven from the core at maximum speed, with all trip circuits failed. Taking 0.5% clad strain as a clad failure criterion, failure was predicted to occur at the top of the active core at about 10s into the transient. A repeat analysis, using an alternative clad yield criterion which is thought to be more realistic, indicated failure at the same position but 24s into the transient. This is after the onset of sodium boiling. Pin failure at the top of the core are likely to cause negative reactivity changes. In this hypothetical accident, pin failures are likely, therefore, to have a moderating effect on the course of the transient. (orig.)

  7. A simulation model for transient response of a gas separation module using a hollow fiber membrane

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-15

    A simulation model has been developed for transient response of a gas separation module using a hollow fiber membrane for the removal of tritium from the atmosphere of the confinement space. The mass transfer process such as sorption and desorption of gases at the surface of the dense layer and the porous support layer, diffusive transfer in the both layers are treated in the model. Sorption isotherm, mass transfer rate and permeance are estimated through step-wise transient response experiments. The present model represents well not only separation factors and recovery ratio at the steady state but also responses to the multi-step wise change in the sweep gas rate.

  8. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    NARCIS (Netherlands)

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L., Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007). Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. Presentation given at the Sixth IASTED International Conference on Web-based Education, 14-16 March,

  9. Rapid response learning of brand logo priming: Evidence that brand priming is not dominated by rapid response learning.

    Science.gov (United States)

    Boehm, Stephan G; Smith, Ciaran; Muench, Niklas; Noble, Kirsty; Atherton, Catherine

    2017-08-31

    Repetition priming increases the accuracy and speed of responses to repeatedly processed stimuli. Repetition priming can result from two complementary sources: rapid response learning and facilitation within perceptual and conceptual networks. In conceptual classification tasks, rapid response learning dominates priming of object recognition, but it does not dominate priming of person recognition. This suggests that the relative engagement of network facilitation and rapid response learning depends on the stimulus domain. Here, we addressed the importance of the stimulus domain for rapid response learning by investigating priming in another domain, brands. In three experiments, participants performed conceptual decisions for brand logos. Strong priming was present, but it was not dominated by rapid response learning. These findings add further support to the importance of the stimulus domain for the relative importance of network facilitation and rapid response learning, and they indicate that brand priming is more similar to person recognition priming than object recognition priming, perhaps because priming of both brands and persons requires individuation.

  10. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    NARCIS (Netherlands)

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16,

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

    International Nuclear Information System (INIS)

    Sugiyama, Takahiko; Tanaka, Masahiro; Munakata, Kenzo; Yamamoto, Ichiro

    2012-01-01

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

  12. Analysis of transient pressure response near a horizontal well - a coupled diffusion-deformation approach

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Wong, R. K. C. [Calgary Univ., AB (Canada); Yeung, K. C. [Suncor Energy Inc., Calgary, AB (Canada)

    1998-12-31

    Results of an analysis of transient pressure near a horizontal well using a coupled diffusion-deformation method are discussed. The results are compared with those obtained from the single diffusivity equation. Implications for practical applications such as well testing are addressed. Results indicate that the diffusion-deformation behaviour of porous material affects the transient pressure response near a horizontal well. Evaluation by conventional well testing, based as it is on the single diffusion equation, would likely result in an overestimate of the permeability value. Comparison of results between the coupled diffusion-deformation approach and the single diffusion equation suggests that a better prediction of pressure response could be derived from total compressibility than by using only fluid compressibility. 6 refs., 9 figs.

  13. Transient response of a cylindrical cavity in viscoelastic saturated porous medium

    Directory of Open Access Journals (Sweden)

    LIU Tao

    2016-10-01

    Full Text Available The study on dynamic characteristics for fluid-solid coupling system in saturated porous medium is of significant academic value and potential application foreground.In this paper,the transient response of a cylindrical cavity in infinite viscoelastic saturated porous medium with the circular lining is studied,and the corresponding results can be used in the design of foundation engineering,such as the tunnel analyses in saturated soil,the nuclear waste disposal engineering,and the exploitation and utilization of geothermal reservoirs and so on.Firstly,based on the porous media theory,the governing equations of coupled system are presented,and the corresponding boundary conditions,initial conditions as well as the joint conditions are derived.Then,the differential quadrature element method and the second-order backward difference scheme are applied to discretize the governing differential equations of the coupled system on the spatial and temporal domains,respectively.Finally,the Newton-Raphson method is adopted to solve the discretization equations with the initial conditions,the transient responses of the coupled system are analyzed,the effects of the parameters are considered,and the validity of the numerical method is verified.

  14. Proceedings of transient thermal-hydraulics and coupled vessel and piping system responses 1991

    International Nuclear Information System (INIS)

    Wang, G.Y.; Shin, Y.W.; Moody, F.J.

    1991-01-01

    This book reports on transient thermal-hydraulics and coupled vessel and piping system responses. Topics covered include: nuclear power plant containment designs; analysis of control rods; gate closure of hydraulic turbines; and shock wave solutions for steam water mixtures in piping systems

  15. A neural model for transient identification in dynamic processes with 'don't know' response

    Energy Technology Data Exchange (ETDEWEB)

    Mol, Antonio C. de A. E-mail: mol@ien.gov.br; Martinez, Aquilino S. E-mail: aquilino@lmp.ufrj.br; Schirru, Roberto E-mail: schirru@lmp.ufrj.br

    2003-09-01

    This work presents an approach for neural network based transient identification which allows either dynamic identification or a 'don't know' response. The approach uses two 'jump' multilayer neural networks (NN) trained with the backpropagation algorithm. The 'jump' network is used because it is useful to dealing with very complex patterns, which is the case of the space of the state variables during some abnormal events. The first one is responsible for the dynamic identification. This NN uses, as input, a short set (in a moving time window) of recent measurements of each variable avoiding the necessity of using starting events. The other one is used to validate the instantaneous identification (from the first net) through the validation of each variable. This net is responsible for allowing the system to provide a 'don't know' response. In order to validate the method, a Nuclear Power Plant (NPP) transient identification problem comprising 15 postulated accidents, simulated for a pressurized water reactor (PWR), was proposed in the validation process it has been considered noisy data in order to evaluate the method robustness. Obtained results reveal the ability of the method in dealing with both dynamic identification of transients and correct 'don't know' response. Another important point studied in this work is that the system has shown to be independent of a trigger signal which indicates the beginning of the transient, thus making it robust in relation to this limitation.

  16. Geometrically Nonlinear Transient Response of Laminated Plates with Nonlinear Elastic Restraints

    Directory of Open Access Journals (Sweden)

    Shaochong Yang

    2017-01-01

    Full Text Available To investigate the dynamic behavior of laminated plates with nonlinear elastic restraints, a varied constraint force model and a systematic numerical procedure are presented in this work. Several kinds of typical relationships of force-displacement for spring are established to simulate the nonlinear elastic restraints. In addition, considering the restraining moments of flexible pads, the pads are modeled by translational and rotational springs. The displacement- dependent constraint forces are added to the right-hand side of equations of motion and treated as additional applied loads. These loads can be explicitly defined, via an independent set of nonlinear load functions. The time histories of transverse displacements at typical points of the laminated plate are obtained through the transient analysis. Numerical examples show that the present method can effectively treat the geometrically nonlinear transient response of plates with nonlinear elastic restraints.

  17. Transformative Learning: Patterns of Psychophysiologic Response and Technology-Enabled Learning and Intervention Systems

    Science.gov (United States)

    2008-09-01

    Psychophysiologic Response and Technology -Enabled Learning and Intervention Systems PRINCIPAL INVESTIGATOR: Leigh W. Jerome, Ph.D...NUMBER Transformative Learning : Patterns of Psychophysiologic Response and Technology - Enabled Learning and Intervention Systems 5b. GRANT NUMBER...project entitled “Transformative Learning : Patterns of Psychophysiologic Response in Technology Enabled Learning and Intervention Systems.” The

  18. Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities

    OpenAIRE

    Sloep, Peter; Kester, Liesbeth; Brouns, Francis; Van Rosmalen, Peter; De Vries, Fred; De Croock, Marcel; Koper, Rob

    2007-01-01

    Sloep, P.B., Kester, L. Brouns, F., Van Rosmalen, P., De Vries, F., De Croock, M., Koper, R. (2007) Ad Hoc Transient Communities to Enhance Social Interaction and Spread Tutor Responsibilities. In V. Uskov (Ed.) The Sixth IASTED International Conference on Web-based Education WBE 2007, March 14-16, Chamonix, France (pp. 549-554). Calgary, Canada: Acta Press.

  19. Proposing Wavelet-Based Low-Pass Filter and Input Filter to Improve Transient Response of Grid-Connected Photovoltaic Systems

    Directory of Open Access Journals (Sweden)

    Bijan Rahmani

    2016-08-01

    Full Text Available Available photovoltaic (PV systems show a prolonged transient response, when integrated into the power grid via active filters. On one hand, the conventional low-pass filter, employed within the integrated PV system, works with a large delay, particularly in the presence of system’s low-order harmonics. On the other hand, the switching of the DC (direct current–DC converters within PV units also prolongs the transient response of an integrated system, injecting harmonics and distortion through the PV-end current. This paper initially develops a wavelet-based low-pass filter to improve the transient response of the interconnected PV systems to grid lines. Further, a damped input filter is proposed within the PV system to address the raised converter’s switching issue. Finally, Matlab/Simulink simulations validate the effectiveness of the proposed wavelet-based low-pass filter and damped input filter within an integrated PV system.

  20. Probabilistic estimates of 1.5-degree carbon budgets based on uncertainty in transient climate response and aerosol forcing

    Science.gov (United States)

    Partanen, A. I.; Mengis, N.; Jalbert, J.; Matthews, D.

    2017-12-01

    Nations agreed to limit the increase in global mean surface temperature relative to the preindustrial era below 2 degrees Celsius and pursue efforts to a more ambitious goal of 1.5 degrees Celsius. To achieve these goals, it is necessary to assess the amount of cumulative carbon emissions compatible with these temperature targets, i.e. so called carbon budgets. In this work, we use the intermediate complexity University of Victoria Earth System Climate Model (UVic ESCM) to assess how uncertainty in aerosol forcing and transient climate response transfers to uncertainty in future carbon budgets for burning fossil fuels. We create a perturbed parameter ensemble of model simulations by scaling aerosol forcing and transient climate response, and assess the likelihood of each simulation by comparing the simulated historical cumulative carbon emissions, CO2 concentration and radiative balance to observations. By weighting the results of each simulation with the likelihood of the simulation, the preliminary results give a carbon budget of 48 Pg C to reach 1.5 degree Celsius temperature increase. The small weighted mean is due to large fraction of simulations with strong aerosol forcing and transient climate response giving negative carbon budgets for this time period. The probability of the carbon budget being over 100 Pg C was 38% and 23% for over 200 Pg carbon budget. The carbon budgets after temperature stabilization at 1.5 degrees are even smaller with a weighted mean of -100 Pg C until the year 2200. The main reason for the negative carbon budgets after temperature stabilization is an assumed strong decrease in aerosol forcing in the 21st century. Conversely, simulations with weak aerosol forcing and transient climate response give positive carbon budgets. Our results highlight both the importance of reducing uncertainty in aerosol forcing and transient climate response, and of taking the non-CO2 forcers into account when estimating carbon budgets.

  1. The transient response for different types of erodable surface thermocouples using finite element analysis

    Directory of Open Access Journals (Sweden)

    Mohammed Hussein

    2007-01-01

    Full Text Available The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel, type-E (chromel-constantan, type-T (copper-constantan, and type-J (iron-constantan with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

  2. Shock Wave Speed and Transient Response of PE Pipe with Steel-Mesh Reinforcement

    Directory of Open Access Journals (Sweden)

    Wuyi Wan

    2016-01-01

    Full Text Available A steel mesh can improve the tensile strength and stability of a polyethylene (PE pipe in a water supply pipeline system. However, it can also cause more severe water hammer hazard due to increasing wave speed. In order to analyze the influence of the steel mesh on the shock wave speed and transient response processes, an improved wave speed formula is proposed by incorporating the equivalent elastic modulus. A field measurement validates the wave speed formula. Moreover, the transient wave propagation and extreme pressures are simulated and compared by the method of characteristics (MOC for reinforced PE pipes with various steel-mesh densities. Results show that a steel mesh can significantly increase the shock wave speed in a PE pipe and thus can cause severe peak pressure and hydraulic surges in a water supply pipeline system. The proposed wave speed formula can more reasonably evaluate the wave speed and improve the transient simulation of steel-mesh-reinforced PE pipes.

  3. Rule Extraction Based on Extreme Learning Machine and an Improved Ant-Miner Algorithm for Transient Stability Assessment.

    Directory of Open Access Journals (Sweden)

    Yang Li

    Full Text Available In order to overcome the problems of poor understandability of the pattern recognition-based transient stability assessment (PRTSA methods, a new rule extraction method based on extreme learning machine (ELM and an improved Ant-miner (IAM algorithm is presented in this paper. First, the basic principles of ELM and Ant-miner algorithm are respectively introduced. Then, based on the selected optimal feature subset, an example sample set is generated by the trained ELM-based PRTSA model. And finally, a set of classification rules are obtained by IAM algorithm to replace the original ELM network. The novelty of this proposal is that transient stability rules are extracted from an example sample set generated by the trained ELM-based transient stability assessment model by using IAM algorithm. The effectiveness of the proposed method is shown by the application results on the New England 39-bus power system and a practical power system--the southern power system of Hebei province.

  4. Rule Extraction Based on Extreme Learning Machine and an Improved Ant-Miner Algorithm for Transient Stability Assessment.

    Science.gov (United States)

    Li, Yang; Li, Guoqing; Wang, Zhenhao

    2015-01-01

    In order to overcome the problems of poor understandability of the pattern recognition-based transient stability assessment (PRTSA) methods, a new rule extraction method based on extreme learning machine (ELM) and an improved Ant-miner (IAM) algorithm is presented in this paper. First, the basic principles of ELM and Ant-miner algorithm are respectively introduced. Then, based on the selected optimal feature subset, an example sample set is generated by the trained ELM-based PRTSA model. And finally, a set of classification rules are obtained by IAM algorithm to replace the original ELM network. The novelty of this proposal is that transient stability rules are extracted from an example sample set generated by the trained ELM-based transient stability assessment model by using IAM algorithm. The effectiveness of the proposed method is shown by the application results on the New England 39-bus power system and a practical power system--the southern power system of Hebei province.

  5. Neural control and transient analysis of the LCL-type resonant converter

    Science.gov (United States)

    Zouggar, S.; Nait Charif, H.; Azizi, M.

    2000-07-01

    This paper proposes a generalised inverse learning structure to control the LCL converter. A feedforward neural network is trained to act as an inverse model of the LCL converter then both are cascaded such that the composed system results in an identity mapping between desired response and the LCL output voltage. Using the large signal model, we analyse the transient output response of the controlled LCL converter in the case of large variation of the load. The simulation results show the efficiency of using neural networks to regulate the LCL converter.

  6. The importance of resolution on the response of mid-latitude transients to enhanced CO2

    International Nuclear Information System (INIS)

    Senior, C.A.

    1994-01-01

    The impact of global warming on the activity of the mid-latitude transients is not well understood. Work with simple models suggests that there will be two competing effects on transient activity. Firstly, there will be a reduction in the baroclinicity due to a smaller pole-equator temperature gradient and secondly there will be increased moisture availability in a warmer atmosphere. A comparison of the mid-latitude transients from two versions of the Hadley Centre for Climate Prediction and Research GCM run at different resolutions is presented and the importance of resolution on the simulation of the high and low frequency variability is discussed. At higher resolution, one of the largest responses of the model to a doubling of atmospheric CO 2 is an enhancement of the westerly flow in the North Atlantic, but this is much reduced at lower resolution. Consistency is sort between changes in the time mean flow and the transient behavior

  7. Honours service-learning & civic responsibility

    Directory of Open Access Journals (Sweden)

    Trae Stewart

    2012-03-01

    Full Text Available 800x600 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Universities have been urged to prepare graduates for successful professional lives and fulfilling lives as civically responsible citizens. Pedagogies of engagement, like service-learning, are touted as one means to achieve these goals. Connections between first-year experience and service-learning programs have been slow to develop. Further, empirical studies on service-learning in university honours education are similarly scarce. This article examines first-semester honours postsecondary students' sense of civic responsibility before and after completing a service-learning program linking a course on the Evolution of Community to direct volunteerism in struggling schools. Based on pre-post-responses (n=119 to the Level III-Civic Responsibility Survey, analysis of variance with repeated measures showed that participants' sense of civic responsibility was significantly increased over time on each of the dependent variables (i.e., community connectedness, civic attitudes, civic efficacy. Community connectedness scores increased significantly at the .005 level, F(1, 118 = 9.703, p = .002. The changes in civic attitudes and civic efficacy scores were extremely significant at the .0005 level, F(1, 118 = 14.498, p < .0005 and F(1, 118 = 23.56, p < .0005, respectively.

  8. Transient response in granular bounded heap flows

    Science.gov (United States)

    Xiao, Hongyi; Ottino, Julio M.; Lueptow, Richard M.; Umbanhowar, Paul B.

    2017-11-01

    Heap formation, a canonical granular flow, is common in industry and is also found in nature. Here, we study the transition between steady flow states in quasi-2D bounded heaps by suddenly changing the feed rate from one fixed value to another. During the transition, in both experiments and discrete element method simulations, an additional wedge of flowing particles propagates over the rising free surface. The downstream edge of the wedge - the wedge front - moves downstream with velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The transient flux profile during the entire transition is well modeled by a diffusion-like equation derived from local mass balance and a local linear relation between the flux and the surface slope. Scalings for the transient kinematics during the flow transitions are developed based on the flux profiles. Funded by NSF Grant CBET-1511450.

  9. Shock-induced thermal wave propagation and response analysis of a viscoelastic thin plate under transient heating loads

    Science.gov (United States)

    Li, Chenlin; Guo, Huili; Tian, Xiaogeng

    2018-04-01

    This paper is devoted to the thermal shock analysis for viscoelastic materials under transient heating loads. The governing coupled equations with time-delay parameter and nonlocal scale parameter are derived based on the generalized thermo-viscoelasticity theory. The problem of a thin plate composed of viscoelastic material, subjected to a sudden temperature rise at the boundary plane, is solved by employing Laplace transformation techniques. The transient responses, i.e. temperature, displacement, stresses, heat flux as well as strain, are obtained and discussed. The effects of time-delay and nonlocal scale parameter on the transient responses are analyzed and discussed. It can be observed that: the propagation of thermal wave is dynamically smoothed and changed with the variation of time-delay; while the displacement, strain, and stress can be rapidly reduced by nonlocal scale parameter, which can be viewed as an important indicator for predicting the stiffness softening behavior for viscoelastic materials.

  10. Transient radiation responses of optical fibers: influence of MCVD process parameters

    International Nuclear Information System (INIS)

    Girard, Sylvain; Alessi, Antonino; Boukenter, Aziz; Ouerdane, Y.; Marcandella, Claude; Richard, Nicolas; Paillet, Philippe; Gaillardin, Marc; Raine, Melanie

    2012-01-01

    A dedicated set of fibers elaborated via the Modified Chemical Vapor Deposition (MCVD) technique is used to study the influence of composition and drawing parameters on their responses to an X-ray pulse representative of the radiation environments associated with Megajoule class lasers. These canonical fibers were designed to highlight the impact of these parameters on the amplitude and kinetics of the transient pulsed X-ray Radiation Induced Attenuation (RIA) at room temperature. From pre-forms differing by their core composition, three optical fibers were elaborated by varying the tension and speed during the drawing process. No or only slight RIA change results from the tested variations in drawing process parameters of Ge-doped, F-doped, and pure-silica-core fibers. This study reveals that the drawing process is not the main parameter to be optimized in order to enhance the radiation tolerance of MCVD specialty optical fibers for the LMJ harsh environment. From the hardness assurance point of view, a specialty fiber sufficiently tolerant to this environment should be robust against changes in the drawing process. The origins of the RIA observed in the different fibers are discussed on the basis of spectral decomposition of their measured RIA spectra, using sets of defects from the literature and related to the different core dopants. This analysis highlights the limits of the well-known defect set to reproduce the RIA above 1 for Ge-doped fibers whereas self-trapped holes and chlorine-related species seem responsible for the transient responses of pure-silica-core and F-doped fibers. (authors)

  11. Transient response of level instruments in a research reactor

    International Nuclear Information System (INIS)

    Cheng, Lap Y.

    1989-01-01

    A numerical model has been developed to simulate the dynamics of water level instruments in a research nuclear reactor. A bubble device, with helium gas as the working fluid, is used to monitor liquid level by sensing the static head pressure due to the height of liquid in the reactor vessel. A finite-difference model is constructed to study the transient response of the water level instruments to pressure perturbations. The field equations which describe the hydraulics of the helium gas in the bubbler device are arranged in the form of a tridiagonal matrix and the field variables are solved at each time step by the Thomas algorithm. Simulation results indicate that the dynamic response of the helium gas depends mainly on the volume and the inertia of the gas in the level instrument tubings. The anomalies in the simulated level indication are attributed to the inherent lag in the level instrument due to the hydraulics of the system. 1 ref., 5 figs

  12. Post-Learning Sleep Transiently Boosts Context Specific Operant Extinction Memory

    Directory of Open Access Journals (Sweden)

    Marion Inostroza

    2017-04-01

    Full Text Available Operant extinction is learning to supress a previously rewarded behavior. It is known to be strongly associated with the specific context in which it was acquired, which limits the therapeutic use of operant extinction in behavioral treatments, e.g., of addiction. We examined whether sleep influences contextual memory of operant extinction over time, using two different recall tests (Recent and Remote. Rats were trained in an operant conditioning task (lever press in context A, then underwent extinction training in context B, followed by a 3-h retention period that contained either spontaneous morning sleep, morning sleep deprivation, or spontaneous evening wakefulness. A recall test was performed either immediately after the 3-h experimental retention period (Recent recall or after 48 h (Remote, in the extinction context B and in a novel context C. The two main findings were: (i at the Recent recall test, sleep in comparison with sleep deprivation and spontaneous wakefulness enhanced extinction memory but, only in the extinction context B; (ii at the Remote recall, extinction performance after sleep was enhanced in both contexts B and C to an extent comparable to levels at Recent recall in context B. Interestingly, extinction performance at Remote recall was also improved in the sleep deprivation groups in both contexts, with no difference to performance in the sleep group. Our results suggest that 3 h of post-learning sleep transiently facilitate the context specificity of operant extinction at a Recent recall. However, the improvement and contextual generalization of operant extinction memory observed in the long-term, i.e., after 48 h, does not require immediate post-learning sleep.

  13. LLL transient-electromagnetics-measurement facility

    International Nuclear Information System (INIS)

    Deadrick, F.J.; Miller, E.K.; Hudson, H.G.

    1975-01-01

    The operation and hardware of the Lawrence Livermore Laboratory's transient-electromagnetics (EM)-measurement facility are described. The transient-EM range is useful for determining the time-domain transient responses of structures to incident EM pulses. To illustrate the accuracy and utility of the EM-measurement facility, actual experimental measurements are compared to numerically computed values

  14. Grounding line transient response in marine ice sheet models

    Directory of Open Access Journals (Sweden)

    A. S. Drouet

    2013-03-01

    Full Text Available Marine ice-sheet stability is mostly controlled by the dynamics of the grounding line, i.e. the junction between the grounded ice sheet and the floating ice shelf. Grounding line migration has been investigated within the framework of MISMIP (Marine Ice Sheet Model Intercomparison Project, which mainly aimed at investigating steady state solutions. Here we focus on transient behaviour, executing short-term simulations (200 yr of a steady ice sheet perturbed by the release of the buttressing restraint exerted by the ice shelf on the grounded ice upstream. The transient grounding line behaviour of four different flowline ice-sheet models has been compared. The models differ in the physics implemented (full Stokes and shallow shelf approximation, the numerical approach, as well as the grounding line treatment. Their overall response to the loss of buttressing is found to be broadly consistent in terms of grounding line position, rate of surface elevation change and surface velocity. However, still small differences appear for these latter variables, and they can lead to large discrepancies (> 100% observed in terms of ice sheet contribution to sea level when cumulated over time. Despite the recent important improvements of marine ice-sheet models in their ability to compute steady state configurations, our results question the capacity of these models to compute short-term reliable sea-level rise projections.

  15. Visual attention to features by associative learning.

    Science.gov (United States)

    Gozli, Davood G; Moskowitz, Joshua B; Pratt, Jay

    2014-11-01

    Expecting a particular stimulus can facilitate processing of that stimulus over others, but what is the fate of other stimuli that are known to co-occur with the expected stimulus? This study examined the impact of learned association on feature-based attention. The findings show that the effectiveness of an uninformative color transient in orienting attention can change by learned associations between colors and the expected target shape. In an initial acquisition phase, participants learned two distinct sequences of stimulus-response-outcome, where stimuli were defined by shape ('S' vs. 'H'), responses were localized key-presses (left vs. right), and outcomes were colors (red vs. green). Next, in a test phase, while expecting a target shape (80% probable), participants showed reliable attentional orienting to the color transient associated with the target shape, and showed no attentional orienting with the color associated with the alternative target shape. This bias seemed to be driven by learned association between shapes and colors, and not modulated by the response. In addition, the bias seemed to depend on observing target-color conjunctions, since encountering the two features disjunctively (without spatiotemporal overlap) did not replicate the findings. We conclude that associative learning - likely mediated by mechanisms underlying visual object representation - can extend the impact of goal-driven attention to features associated with a target stimulus. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Application of ADINA fluid element for transient response analysis of fluid-structure system

    International Nuclear Information System (INIS)

    Sakurai, Y.; Kodama, T.; Shiraishi, T.

    1985-01-01

    Pressure propagation and Fluid-Structure Interaction (FSI) in 3D space were simulated by general purpose finite element program ADINA using the displacement-based fluid element which presumes inviscid and compressible fluid with no net flow. Numerical transient solution was compared with the measured data of an FSI experiment and was found to fairly agree with the measured. In the next step, post analysis was conducted for a blowdown experiment performed with a 1/7 scaled reactor pressure vessel and a flexible core barrel and the code performance was found to be satisfactory. It is concluded that the transient response of the core internal structure of a PWR during the initial stage of LOCA can be analyzed by the displacement-based finite fluid element and the structural element. (orig.)

  17. DEFORM-4: fuel pin characterization and transient response in the SAS4A accident analysis code system

    International Nuclear Information System (INIS)

    Miles, K.J.; Hill, D.J.

    1986-01-01

    The DEFORM-4 module is the segment of the SAS4A Accident Analysis Code System that calculates the fuel pin characterization in response to a steady state irradiation history, thereby providing the initial conditions for the transient calculation. The various phenomena considered include fuel porosity migration, fission gas bubble induced swelling, fuel cracking and healing, fission gas release, cladding swelling, and the thermal-mechanical state of the fuel and cladding. In the transient state, the module continues the thermal-mechanical response calculation, including fuel melting and central cavity pressurization, until cladding failure is predicted and one of the failed fuel modules is initiated. Comparisons with experimental data have demonstrated the validity of the modeling approach

  18. Extraction of diagnostic parameters from the transient response of a porous electro ceramic gas sensor

    International Nuclear Information System (INIS)

    Hossein-Babaei, F.; Orvatinia, M.

    2004-01-01

    A novel concept for the diagnosis of a pure target gas in air is presented. The method employs a resistive gas sensor with a mm-thick highly porous electro ceramic gas sensitive body. The diagnosis is based on the fact that the diffusion time of the target gas through the porous body would depend on its molecular properties. The transient response of the device was analyzed based on a diffusion reaction equation. The solutions of the equation were shown to be of diagnostic merits. Such a device was fabricated by partial sintering of a Zn O body formed by low pressure pressing. The transient responses of the device to methanol, ethanol, poropanol and butanol were recorded. The analytical data, and the diagnostic parameters were resulted as the fitting parameters. Comparison of the parameters obtained with those available from the calibration experiments afforded target gas identification

  19. Company learning about corporate social responsibility

    NARCIS (Netherlands)

    Cramer, J.M.

    2005-01-01

    This article analyses the learning experiences gained by 19 Dutch companies when implementing the concept of corporate social responsibility in their own business practices. It is concluded that learning processes took place at individual level and, in certain cases, at group level. Learning at

  20. Transient analysis on the SMART-P anticipated transients without scram

    International Nuclear Information System (INIS)

    Yang, S. H.; Bae, K. H.; Kim, H. C.; Zee, S. Q.

    2005-01-01

    Anticipated transients without scram (ATWS) are anticipated operational occurrences accompanied by a failure of an automatic reactor trip when required. Although the occurrence probability of the ATWS events is considerably low, these events can result in unacceptable consequences, i.e. the pressurization of the reactor coolant system (RCS) up to an unacceptable range and a core-melting situation. Therefore, the regulatory body requests the installation of a protection system against the ATWS events. According to the request, a diverse protection system (DPS) is installed in the SMART-P (System-integrated Modular Advanced ReacTor-Pilot). This paper presents the results of the transient analysis performed to identify the performance of the SMART-P against the ATWS. In the analysis, the TASS/SMR (Transients And Setpoint Simulation/Small and Medium Reactor) code is applied to identify the thermal hydraulic response of the RCS during the transients

  1. The development of automaticity in short-term memory search: Item-response learning and category learning.

    Science.gov (United States)

    Cao, Rui; Nosofsky, Robert M; Shiffrin, Richard M

    2017-05-01

    In short-term-memory (STM)-search tasks, observers judge whether a test probe was present in a short list of study items. Here we investigated the long-term learning mechanisms that lead to the highly efficient STM-search performance observed under conditions of consistent-mapping (CM) training, in which targets and foils never switch roles across trials. In item-response learning, subjects learn long-term mappings between individual items and target versus foil responses. In category learning, subjects learn high-level codes corresponding to separate sets of items and learn to attach old versus new responses to these category codes. To distinguish between these 2 forms of learning, we tested subjects in categorized varied mapping (CV) conditions: There were 2 distinct categories of items, but the assignment of categories to target versus foil responses varied across trials. In cases involving arbitrary categories, CV performance closely resembled standard varied-mapping performance without categories and departed dramatically from CM performance, supporting the item-response-learning hypothesis. In cases involving prelearned categories, CV performance resembled CM performance, as long as there was sufficient practice or steps taken to reduce trial-to-trial category-switching costs. This pattern of results supports the category-coding hypothesis for sufficiently well-learned categories. Thus, item-response learning occurs rapidly and is used early in CM training; category learning is much slower but is eventually adopted and is used to increase the efficiency of search beyond that available from item-response learning. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  2. Functional difference between sustained and transient modulations of cognitive control in the simon task: evidence from false alarm responses on no-go trials.

    Science.gov (United States)

    Hasegawa, Kunihiro; Takahashi, Shin'ya

    2013-01-01

    Cognitive control in response compatibility tasks is modulated by the task context. Two types of contextual modulations have been demonstrated; sustained (block-wise) and transient (trial-by-trial). Recent research suggests that these modulations have different underlying mechanisms. This study presents new evidence supporting this claim by comparing false alarm (FA) responses on no-go trials of the Simon task between the sustained and transient contexts. In Experiment 1, the sustained context was manipulated so that a block included a larger number of incongruent trials. Results showed that participants made more FA responses by the hand opposite to the stimulus location. This suggests a generation of response bias in which the task-irrelevant location information is utilized in a reversed manner (i.e., to respond with the right hand to a stimulus presented on the left side and vice versa). Next, Experiment 2 examined the effect of the transient context and found that overall FA rate was lower when a no-go trial was preceded by an incongruent trial than by a congruent trial, whereas such response bias as that shown in Experiment 1 was not demonstrated. This suggests that the transient conflict context enhances inhibition of the task-irrelevant process but does not make the task-irrelevant information actively usable. Based on these results, we propound two types of cognitive control modulations as adaptive behaviors: response biasing based on utilization of the task-irrelevant information under the sustained conflict context and transient enhancement of inhibition of the task-irrelevant process based on the online conflict monitoring.

  3. A Capacitor-Free, Fast Transient Response Linear Voltage Regulator In a 180nm CMOS

    DEFF Research Database (Denmark)

    Deleuran, Alexander N.; Lindbjerg, Nicklas; Pedersen, Martin K.

    2015-01-01

    A 1.8 V capacitor-free linear regulator with fast transient response based on a new topology with a fast and slow regulation loop is presented. The design has been laid out and simulated in a 0.18 µm CMOS process. The design has a low component count and is tailored for system-on-chip integration...

  4. Transient magnetoviscosity of dilute ferrofluids

    International Nuclear Information System (INIS)

    Soto-Aquino, Denisse; Rinaldi, Carlos

    2011-01-01

    The magnetic field induced change in the viscosity of a ferrofluid, commonly known as the magnetoviscous effect and parameterized through the magnetoviscosity, is one of the most interesting and practically relevant aspects of ferrofluid phenomena. Although the steady state behavior of ferrofluids under conditions of applied constant magnetic fields has received considerable attention, comparatively little attention has been given to the transient response of the magnetoviscosity to changes in the applied magnetic field or rate of shear deformation. Such transient response can provide further insight into the dynamics of ferrofluids and find practical application in the design of devices that take advantage of the magnetoviscous effect and inevitably must deal with changes in the applied magnetic field and deformation. In this contribution Brownian dynamics simulations and a simple model based on the ferrohydrodynamics equations are applied to explore the dependence of the transient magnetoviscosity for two cases: (I) a ferrofluid in a constant shear flow wherein the magnetic field is suddenly turned on, and (II) a ferrofluid in a constant magnetic field wherein the shear flow is suddenly started. Both simulations and analysis show that the transient approach to a steady state magnetoviscosity can be either monotonic or oscillatory depending on the relative magnitudes of the applied magnetic field and shear rate. - Research Highlights: →Rotational Brownian dynamics simulations were used to study the transient behavior of the magnetoviscosity of ferrofluids. →Damped and oscillatory approach to steady state magnetoviscosity was observed for step changes in shear rate and magnetic field. →A model based on the ferrohydrodynamics equations qualitatively captured the damped and oscillatory features of the transient response →The transient behavior is due to the interplay of hydrodynamic, magnetic, and Brownian torques on the suspended particles.

  5. Effect of axial stress on the transient mechanical response of 20%, cold-worked Type 316 stainless-steel cladding

    International Nuclear Information System (INIS)

    Yamada, H.

    1979-01-01

    To understand the effects of the fuel-cladding mechanical interaction on the failure of 20% cold-worked Type 316 stainless-steel cladding during anticipated nuclear reactor transients, the transient mechanical response of the cladding was investigated using a transient tube burst method at a heating rate of 5.6 0 C/s and axial-to-hoop-stress ratios in the range of 1/2 to 2. The failure temperatures were observed to remain essentially constant for the transient tests at axial-to-hoop-stress ratios between 1/2 and 1, but to decrease with an increase in axial-to-hoop-stress ratios above unity. The uniform diametral strains to failure were observed to decrease monotonically with an increase in axial-to-hoop-stress ratio from 1/2 to 2, and in general, the uniform axial strains to failure were observed to increase with an increase in axial-to-hoop-stress ratio. The fracture of the cladding during thermal transients was found to be strongly affected by the maximum principal stress but not by the effective stress

  6. Sustained and transient oscillations and chaos induced by delayed antiviral immune response in an immunosuppressive infection model.

    Science.gov (United States)

    Shu, Hongying; Wang, Lin; Watmough, James

    2014-01-01

    Sustained and transient oscillations are frequently observed in clinical data for immune responses in viral infections such as human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. To account for these oscillations, we incorporate the time lag needed for the expansion of immune cells into an immunosuppressive infection model. It is shown that the delayed antiviral immune response can induce sustained periodic oscillations, transient oscillations and even sustained aperiodic oscillations (chaos). Both local and global Hopf bifurcation theorems are applied to show the existence of periodic solutions, which are illustrated by bifurcation diagrams and numerical simulations. Two types of bistability are shown to be possible: (i) a stable equilibrium can coexist with another stable equilibrium, and (ii) a stable equilibrium can coexist with a stable periodic solution.

  7. Learning approach to the detection of gravitational wave transients

    International Nuclear Information System (INIS)

    Chassande-Mottin, E.

    2003-01-01

    We investigate the class of quadratic detectors (i.e., the statistic is a bilinear function of the data) for the detection of poorly modeled gravitational transients of short duration. We point out that all such detection methods are equivalent to passing the signal through a filter bank and linearly combining the output energy. Existing methods for the choice of the filter bank and of the weight parameters (to be multiplied by the output energy of each filter before summation) rely essentially on the two following ideas: (i) the use of the likelihood function based on a (possibly noninformative) statistical model of the signal and the noise; (ii) the use of Monte Carlo simulations for the tuning of parametric filters to get the best detection probability while keeping the false alarm rate fixed. We propose a third approach according to which the filter bank is 'learned' from a set of training data. By-products of this viewpoint are that, contrarily to previous methods, (i) there is no requirement of an explicit description of the probability density function of the data when the signal is present and (ii) the filters we use are nonparametric. The learning procedure may be described as a two step process: first, estimate the mean and covariance of the signal with the training data; second, find the filters which maximize a contrast criterion referred to as the deflection between the 'noise only' and 'signal + noise' hypotheses. The deflection is homogeneous to the signal-to-noise ratio and it uses the quantities estimated at the first step. We apply this original method to the problem of the detection of supernovae core collapses. We use the catalog of waveforms provided recently by Dimmelmeier et al. to train our algorithm. We expect such a detector to have better performances in this particular problem provided that the reference signals are reliable

  8. Dayside magnetospheric and ionospheric responses to a foreshock transient on June 25, 2008: 2. 2-D evolution based on dayside auroral imaging

    OpenAIRE

    Wang, Boyi; Nishimura, Yukitoshi; Hietala, Heli; Shen, Xiao-Chen; Shi, Quanqi; Zhang, Hui; Lyons, Larry; Zou, Ying; Angelopoulos, Vassilis; Ebihara, Yusuke; Weatherwax, Allan

    2018-01-01

    The foreshock region involves localized and transient structures such as foreshock cavities and hot flow anomalies due to solar wind-bow shock interactions, and foreshock transients have been shown to lead to magnetospheric and ionospheric responses. In this paper, the interaction between a foreshock transient and the magnetosphere-ionosphere system is investigated using dayside aurora imagers revealing structures and propagation in greater detail than previously possible. A foreshock transie...

  9. Japanese Encephalitis Virus Infection Results in Transient Dysfunction of Memory Learning and Cholinesterase Inhibition.

    Science.gov (United States)

    Chauhan, Prashant Singh; Khanna, Vinay Kumar; Kalita, Jayantee; Misra, Usha Kant

    2017-08-01

    Cholinergic system has an important role in memory and learning. Abnormal cognitive and behavioral changes have been reported in Japanese encephalitis (JE), but their basis has not been comprehensively evaluated. In this study, we report memory and learning and its association with acetylcholinesterase (AChE) activity, JE virus titer, and with histopathological observations in a rat model of JE. Wistar rats were intracerebrally inoculated on 12th day with 3 × 10 6  pfu/ml of JE virus. Memory and learning were assessed by the active and passive avoidance tests on 10, 33, and 48 days post inoculation (dpi). After 10, 33, and 48 dpi AChE activity, Japanese encephalitis virus (JEV) titer and histopathological changes were studied in the frontal cortex, thalamus, midbrain, cerebellum, and hippocampus. There was significant impairment in memory and learning on 10 dpi which started improving from 33 dpi to 48 dpi by active avoidance test. Passive avoidance test showed decrease in transfer latency time of retention trial compared to acquisition on first, second, and third retention day trial compared to controls. AChE inhibition was more marked in the hippocampus, frontal cortex, and cerebellum on 10 dpi. However, AChE activity started improving from 33 dpi to 48 dpi. AChE activity in the thalamus and midbrain correlated with active avoidance test on 10 dpi and 33 dpi. Histopathological studies also revealed improvement on 33 and 48 compared to 10 dpi. The present study demonstrates transient memory and learning impairment which was associated with reduction in AChE, JEV titer, and damage in different brain regions of JEV infected rats.

  10. Implicit learning and emotional responses in nine-month-old infants.

    Science.gov (United States)

    Angulo-Barroso, Rosa M; Peciña, Susana; Lin, Xu; Li, Mingyan; Sturza, Julia; Shao, Jie; Lozoff, Betsy

    2017-08-01

    To study the interplay between motor learning and emotional responses of young infants, we developed a contingent learning paradigm that included two related, difficult, operant tasks. We also coded facial expression to characterise emotional response to learning. In a sample of nine-month-old healthy Chinese infants, 44.7% achieved learning threshold during this challenging arm-conditioning test. Some evidence of learning was observed at the beginning of the second task. The lowest period of negative emotions coincided with the period of maximum movement responses after the initiation of the second task, and movement responses negatively correlated with the frequency of negative emotions. Positive emotions, while generally low throughout the task, increased during peak performance especially for learners. Peak frequency of movement responses was positively correlated with the frequency of positive emotions. Despite the weak evidence of learning this difficult task, our results from the learners would suggest that increasing positive emotions, and perhaps down-regulating negative emotional responses, may be important for improving performance and learning a complex operant task in infancy. Further studies are necessary to determine the role of emotions in learning difficult tasks in infancy.

  11. Prenatal complex rhythmic music sound stimulation facilitates postnatal spatial learning but transiently impairs memory in the domestic chick.

    Science.gov (United States)

    Kauser, H; Roy, S; Pal, A; Sreenivas, V; Mathur, R; Wadhwa, S; Jain, S

    2011-01-01

    Early experience has a profound influence on brain development, and the modulation of prenatal perceptual learning by external environmental stimuli has been shown in birds, rodents and mammals. In the present study, the effect of prenatal complex rhythmic music sound stimulation on postnatal spatial learning, memory and isolation stress was observed. Auditory stimulation with either music or species-specific sounds or no stimulation (control) was provided to separate sets of fertilized eggs from day 10 of incubation. Following hatching, the chicks at age 24, 72 and 120 h were tested on a T-maze for spatial learning and the memory of the learnt task was assessed 24 h after training. In the posthatch chicks at all ages, the plasma corticosterone levels were estimated following 10 min of isolation. The chicks of all ages in the three groups took less (p memory after 24 h of training, only the music-stimulated chicks at posthatch age 24 h took a significantly longer (p music sounds facilitates spatial learning, though the music stimulation transiently impairs postnatal memory. 2011 S. Karger AG, Basel.

  12. Transient response of Babcock and Wilcox-designed reactors

    International Nuclear Information System (INIS)

    1980-05-01

    On February 26, 1980, the Crystal River Unit No. 3 Nuclear Generating Plant, designed by the Babcock and Wilcox Company (B and W), experienced an incident involving a malfunction in an instrumentation and control system power supply. Faced with the Crystal River Unit 3 incident and the apparently high frequency of such near similar types of transients in other B and W designed plants, a special Task Force was established within the Office of Nuclear Reactor Regulation to provide an assessment of the apparent sensitivity of the B and W designed plants to such transients and the consequences of malfunctions and failures of the integrated control system and non-nuclear instrumentation. This report provides an assessment of these issues

  13. Transient thermal response of a packed bed for energy storage unit utilizing phase change material: experimental and numerical study

    International Nuclear Information System (INIS)

    Bemansour, A.

    2006-01-01

    The present work concerns the numerical and experimental study of the transient response of a packed bed latent heat thermal energy storage system. Experiments were carried out to measures the transient temperature distributions inside a cylindrical bed, which is randomly packed with spheres having uniform sizes and encapsulated the paraffin wax as a phase change material (PCM), with air as a working fluid. A two-dimensional separate phases formulation is used to develop a numerical analysis of the transient response of the bed, considering the influence of both axial and radial thermal dispersion. The fluid energy equation was transformed by finite difference approximation and solved by alternating direction implicit scheme, while the PCM energy equation was solved using fully explicit scheme. This analysis can be applied for both charging and recovery modes and a broad range of Reynolds numbers. Measurements of both fluid and PCM temperature were conducted at different axial and radial positions and at different operating parameters. Experimental measurements of temperature distribution compare favorably with the numerical results over a broad range of Reynolds numbers.(Author)

  14. PWR [pressurized water reactor] pressurizer transient response: Final report

    International Nuclear Information System (INIS)

    Murphy, S.I.

    1987-08-01

    To predict PWR pressurizer transients, Ahl proposed a three region model with a universal coefficient to represent condensation on the water surface. Specifically, this work checks the need for three regions and the modeling of the interfacial condensation coefficient. A computer model has been formulated using the basic mass and energy conservation laws. A two region vapor and liquid model was first used to predict transients run on a one-eleventh scale Freon pressurizer. These predictions verified the need for a second liquid region. As a result, a three region model was developed and used to predict full-scale pressurizer transients at TMI-2, Shippingport, and Stade. Full-scale pressurizer predictions verified the three region model and pointed out the shortcomings of Ahl's universal condensation coefficient. In addition, experiments were run using water at low pressure to study interface condensation. These experiments showed interface condensation to be significant only when spray flow is turned on; this result was incorporated in the final three region model

  15. Understanding Epileptiform After-Discharges as Rhythmic Oscillatory Transients.

    Science.gov (United States)

    Baier, Gerold; Taylor, Peter N; Wang, Yujiang

    2017-01-01

    Electro-cortical activity in patients with epilepsy may show abnormal rhythmic transients in response to stimulation. Even when using the same stimulation parameters in the same patient, wide variability in the duration of transient response has been reported. These transients have long been considered important for the mapping of the excitability levels in the epileptic brain but their dynamic mechanism is still not well understood. To investigate the occurrence of abnormal transients dynamically, we use a thalamo-cortical neural population model of epileptic spike-wave activity and study the interaction between slow and fast subsystems. In a reduced version of the thalamo-cortical model, slow wave oscillations arise from a fold of cycles (FoC) bifurcation. This marks the onset of a region of bistability between a high amplitude oscillatory rhythm and the background state. In vicinity of the bistability in parameter space, the model has excitable dynamics, showing prolonged rhythmic transients in response to suprathreshold pulse stimulation. We analyse the state space geometry of the bistable and excitable states, and find that the rhythmic transient arises when the impending FoC bifurcation deforms the state space and creates an area of locally reduced attraction to the fixed point. This area essentially allows trajectories to dwell there before escaping to the stable steady state, thus creating rhythmic transients. In the full thalamo-cortical model, we find a similar FoC bifurcation structure. Based on the analysis, we propose an explanation of why stimulation induced epileptiform activity may vary between trials, and predict how the variability could be related to ongoing oscillatory background activity. We compare our dynamic mechanism with other mechanisms (such as a slow parameter change) to generate excitable transients, and we discuss the proposed excitability mechanism in the context of stimulation responses in the epileptic cortex.

  16. Effect of helium pressure on the response of unirradiated UO2 subjected to thermal transients

    International Nuclear Information System (INIS)

    Fenske, G.R.; Chapello, P.M.; Emerson, J.E.; Poeppel, R.B.

    1983-01-01

    The effect of helium pressure on the transient response of unirradiated depleted UO 2 subjected to simulated hypothetical loss-of-flow accidents in a gas-cooled fast reactor was examined by use of the direct electrical heating technique. Transient tests were performed at pressures ranging from 7 to 10 X 10 5 Pa(7 to 10 atm) to 7 to 8 MPa (70 to 80 atm) on radially restrained and unrestrained fuel segments. The average heating rates ranged from about17 to 240 J/g x s. The results indicate that while the mechanical integrity of the fuel segment was independent of the test pressure, the rapid ejection of molten fuel from pellet interfaces of unrestrained fuel, observed at the lower pressures, was delayed or suppressed at the higher pressures

  17. Transient and steady-state auditory gamma-band responses in first-degree relatives of people with autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Rojas Donald C

    2011-07-01

    Full Text Available Abstract Background Stimulus-related γ-band oscillations, which may be related to perceptual binding, are reduced in people with autism spectrum disorders (ASD. The purpose of this study was to examine auditory transient and steady-state γ-band findings in first-degree relatives of people with ASD to assess the potential familiality of these findings in ASD. Methods Magnetoencephalography (MEG recordings in 21 parents who had a child with an autism spectrum disorder (pASD and 20 healthy adult control subjects (HC were obtained. Gamma-band phase locking factor (PLF, and evoked and induced power to 32, 40 and 48 Hz amplitude-modulated sounds were measured for transient and steady-state responses. Participants were also tested on a number of behavioral and cognitive assessments related to the broad autism phenotype (BAP. Results Reliable group differences were seen primarily for steady-state responses. In the left hemisphere, pASD subjects exhibited lower phase-locked steady-state power in all three conditions. Total γ-band power, including the non-phase-locked component, was also reduced in the pASD group. In addition, pASD subjects had significantly lower PLF than the HC group. Correlations were seen between MEG measures and BAP measures. Conclusions The reduction in steady-state γ-band responses in the pASD group is consistent with previous results for children with ASD. Steady-state responses may be more sensitive than transient responses to phase-locking errors in ASD. Together with the lower PLF and phase-locked power in first-degree relatives, correlations between γ-band measures and behavioral measures relevant to the BAP highlight the potential of γ-band deficits as a potential new autism endophenotype.

  18. The Multiscale Material Point Method for Simulating Transient Responses

    Science.gov (United States)

    Chen, Zhen; Su, Yu-Chen; Zhang, Hetao; Jiang, Shan; Sewell, Thomas

    2015-06-01

    To effectively simulate multiscale transient responses such as impact and penetration without invoking master/slave treatment, the multiscale material point method (Multi-MPM) is being developed in which molecular dynamics at nanoscale and dissipative particle dynamics at mesoscale might be concurrently handled within the framework of the original MPM at microscale (continuum level). The proposed numerical scheme for concurrently linking different scales is described in this paper with simple examples for demonstration. It is shown from the preliminary study that the mapping and re-mapping procedure used in the original MPM could coarse-grain the information at fine scale and that the proposed interfacial scheme could provide a smooth link between different scales. Since the original MPM is an extension from computational fluid dynamics to solid dynamics, the proposed Multi-MPM might also become robust for dealing with multiphase interactions involving failure evolution. This work is supported in part by DTRA and NSFC.

  19. Static Tensile and Transient Dynamic Response of Cracked Aluminum Plate Repaired with Composite Patch - Numerical Study

    Science.gov (United States)

    Khalili, S. M. R.; Shariyat, M.; Mokhtari, M.

    2014-06-01

    In this study, the central cracked aluminum plates repaired with two sided composite patches are investigated numerically for their response to static tensile and transient dynamic loadings. Contour integral method is used to define and evaluate the stress intensity factors at the crack tips. The reinforcement for the composite patches is carbon fibers. The effect of adhesive thickness and patch thickness and configuration in tensile loading case and pre-tension, pre-compression and crack length effect on the evolution of the mode I stress intensity factor (SIF) (KI) of the repaired structure under transient dynamic loading case are examined. The results indicated that KI of the central cracked plate is reduced by 1/10 to 1/2 as a result of the bonded composite patch repair in tensile loading case. The crack length and the pre-loads are more effective in repaired structure in transient dynamic loading case in which, the 100 N pre-compression reduces the maximum KI for about 40 %, and the 100 N pre-tension reduces the maximum KI after loading period, by about 196 %.

  20. Mimicking mechanical response of natural tissues. Strain hardening induced by transient reticulation in lactose-modified chitosan (chitlac).

    Science.gov (United States)

    Cok, Michela; Sacco, Pasquale; Porrelli, Davide; Travan, Andrea; Borgogna, Massimiliano; Marsich, Eleonora; Paoletti, Sergio; Donati, Ivan

    2018-01-01

    The effect of transient cross-links has been explored on a lactose-modified chitosan, which previously had shown interesting biological features. The presence of galactose side chains and of the polyol spacer resulted particularly appealing for the reticulation by borate ions. The interaction between chitlac and borax was investigated by means of 11 B NMR while rheology pointed to a marked non-linear behavior depending on the amount of borax added to the system. The presence of limited amount of cross-linking ion led to dilatant behavior when the steady flow curve was measured. In addition, strain stiffening was noticed on elastic response upon exceeding a critical stress, indicating a transient nature in the formation of the cross-links. The non-linear response of chitlac in the presence of borax compared surprisingly well with the one showed by proteins composing the natural ECM pointing at a possible role of mechanotransduction in the biological significance of the modified chitosan. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Frequency-dependent transient response of an oscillating electrically actuated droplet

    International Nuclear Information System (INIS)

    Dash, S; Kumari, N; Garimella, S V

    2012-01-01

    The transient response of a millimeter-sized sessile droplet under electrical actuation is experimentally investigated. Under dc actuation, the droplet spreading rate increases as the applied voltage is increased due to the higher electrical forces induced. At sufficiently high dc voltages, competition between the electrical actuation force, droplet inertia, the retarding surface tension force and contact line friction leads to droplet oscillation. The timescale for the droplet to attain its maximum wetted diameter during step actuation is analyzed. Systematic experiments are conducted over a frequency range of 5–200 Hz and actuation voltages of 40–80 V rms to determine the dependence of droplet oscillation on these parameters. The response of the droplet to different actuation frequencies and voltages is determined in terms of its contact angle and contact radius variation. The frequency of the driving force (equal to twice the frequency of the applied electrical signal) determines the mode of oscillation of the droplet which, together with its resonance characteristics, governs whether the droplet contact angle and contact radius vary in phase or out of phase with each other. In addition to the primary frequency response at the electrical forcing frequency, the droplet oscillation exhibits sub-harmonic oscillation at half of the forcing frequency that is attributed to the parametric nature of the electrical force acting on the triple contact line of the droplet. (paper)

  2. CFORM- LINEAR CONTROL SYSTEM DESIGN AND ANALYSIS: CLOSED FORM SOLUTION AND TRANSIENT RESPONSE OF THE LINEAR DIFFERENTIAL EQUATION

    Science.gov (United States)

    Jamison, J. W.

    1994-01-01

    CFORM was developed by the Kennedy Space Center Robotics Lab to assist in linear control system design and analysis using closed form and transient response mechanisms. The program computes the closed form solution and transient response of a linear (constant coefficient) differential equation. CFORM allows a choice of three input functions: the Unit Step (a unit change in displacement); the Ramp function (step velocity); and the Parabolic function (step acceleration). It is only accurate in cases where the differential equation has distinct roots, and does not handle the case for roots at the origin (s=0). Initial conditions must be zero. Differential equations may be input to CFORM in two forms - polynomial and product of factors. In some linear control analyses, it may be more appropriate to use a related program, Linear Control System Design and Analysis (KSC-11376), which uses root locus and frequency response methods. CFORM was written in VAX FORTRAN for a VAX 11/780 under VAX VMS 4.7. It has a central memory requirement of 30K. CFORM was developed in 1987.

  3. PWR systems transient analysis

    International Nuclear Information System (INIS)

    Kennedy, M.F.; Peeler, G.B.; Abramson, P.B.

    1985-01-01

    Analysis of transients in pressurized water reactor (PWR) systems involves the assessment of the response of the total plant, including primary and secondary coolant systems, steam piping and turbine (possibly including the complete feedwater train), and various control and safety systems. Transient analysis is performed as part of the plant safety analysis to insure the adequacy of the reactor design and operating procedures and to verify the applicable plant emergency guidelines. Event sequences which must be examined are developed by considering possible failures or maloperations of plant components. These vary in severity (and calculational difficulty) from a series of normal operational transients, such as minor load changes, reactor trips, valve and pump malfunctions, up to the double-ended guillotine rupture of a primary reactor coolant system pipe known as a Large Break Loss of Coolant Accident (LBLOCA). The focus of this paper is the analysis of all those transients and accidents except loss of coolant accidents

  4. A Decentralized Current-Sharing Controller Endows Fast Transient Response to Parallel DC-DC Converters

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Han, Renke

    2018-01-01

    This paper proposes a decentralized current-sharing control strategy to endow fast transient response to paralleled DC-DC converters systems, such as DC microgrids or distributed power systems. The proposed controller consist of two main control loops: an external voltage droop control for current......-sharing proposes and an internal current loop. The external droop control loop is designed as a voltage loop with embedded virtual impedance, which avoids the use of a slow voltage loop and a separate extra virtual impedance loop that may limit the system bandwidth. The internal current loop, thanks...... and the proposed embedded-virtual-impedance based I-V droop. In order to compare the dynamic response performances between two droop controllers, their state-space models have been developed and analyzed in this paper. The results show that the dynamic response of the I-V droop control is faster than...

  5. NALAP: an LMFBR system transient code

    International Nuclear Information System (INIS)

    Martin, B.A.; Agrawal, A.K.; Albright, D.C.; Epel, L.G.; Maise, G.

    1975-07-01

    NALAP is a LMFBR system transient code. This code, adapted from the light water reactor transient code RELAP 3B, simulates thermal-hydraulic response of sodium cooled fast breeder reactors when subjected to postulated accidents such as a massive pipe break as well as a variety of other upset conditions that do not disrupt the system geometry. Various components of the plant are represented by control volumes. These control volumes are connected by junctions some of which may be leak or fill junctions. The fluid flow equations are modeled as compressible, single-stream flow with momentum flux in one dimension. The transient response is computed by integrating the thermal-hydraulic conservation equations from user-initialized operating conditions by an implicit numerical scheme. Point kinetics approximation is used to represent the time dependent heat generation in the reactor core

  6. Focused cognitive control in dishonesty: Evidence for predominantly transient conflict adaptation.

    Science.gov (United States)

    Foerster, Anna; Pfister, Roland; Schmidts, Constantin; Dignath, David; Wirth, Robert; Kunde, Wilfried

    2018-04-01

    Giving a dishonest response to a question entails cognitive conflict due to an initial activation of the truthful response. Following conflict monitoring theory, dishonest responding could therefore elicit transient and sustained control adaptation processes to mitigate such conflict, and the current experiments take on the scope and specificity of such conflict adaptation in dishonesty. Transient adaptation reduces differences between honest and dishonest responding following a recent dishonest response. Sustained adaptation has a similar behavioral signature but is driven by the overall frequency of dishonest responding. Both types of adaptation to recent and frequent dishonest responses have been separately documented, leaving open whether control processes in dishonest responding can flexibly adapt to transient and sustained conflict signals of dishonest and other actions. This was the goal of the present experiments which studied (dis)honest responding to autobiographical yes/no questions. Experiment 1 showed robust transient adaptation to recent dishonest responses whereas sustained control adaptation failed to exert an influence on behavior. It further revealed that transient effects may create a spurious impression of sustained adaptation in typical experimental settings. Experiments 2 and 3 examined whether dishonest responding can profit from transient and sustained adaption processes triggered by other behavioral conflicts. This was clearly not the case: Dishonest responding adapted markedly to recent (dis)honest responses but not to any context of other conflicts. These findings indicate that control adaptation in dishonest responding is strong but surprisingly focused and they point to a potential trade-off between transient and sustained adaptation. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  7. Transient coupled calculations of the Molten Salt Fast Reactor using the Transient Fission Matrix approach

    Energy Technology Data Exchange (ETDEWEB)

    Laureau, A., E-mail: laureau.axel@gmail.com; Heuer, D.; Merle-Lucotte, E.; Rubiolo, P.R.; Allibert, M.; Aufiero, M.

    2017-05-15

    Highlights: • Neutronic ‘Transient Fission Matrix’ approach coupled to the CFD OpenFOAM code. • Fission Matrix interpolation model for fast spectrum homogeneous reactors. • Application for coupled calculations of the Molten Salt Fast Reactor. • Load following, over-cooling and reactivity insertion transient studies. • Validation of the reactor intrinsic stability for normal and accidental transients. - Abstract: In this paper we present transient studies of the Molten Salt Fast Reactor (MSFR). This generation IV reactor is characterized by a liquid fuel circulating in the core cavity, requiring specific simulation tools. An innovative neutronic approach called “Transient Fission Matrix” is used to perform spatial kinetic calculations with a reduced computational cost through a pre-calculation of the Monte Carlo spatial and temporal response of the system. Coupled to this neutronic approach, the Computational Fluid Dynamics code OpenFOAM is used to model the complex flow pattern in the core. An accurate interpolation model developed to take into account the thermal hydraulics feedback on the neutronics including reactivity and neutron flux variation is presented. Finally different transient studies of the reactor in normal and accidental operating conditions are detailed such as reactivity insertion and load following capacities. The results of these studies illustrate the excellent behavior of the MSFR during such transients.

  8. Transient coupled calculations of the Molten Salt Fast Reactor using the Transient Fission Matrix approach

    International Nuclear Information System (INIS)

    Laureau, A.; Heuer, D.; Merle-Lucotte, E.; Rubiolo, P.R.; Allibert, M.; Aufiero, M.

    2017-01-01

    Highlights: • Neutronic ‘Transient Fission Matrix’ approach coupled to the CFD OpenFOAM code. • Fission Matrix interpolation model for fast spectrum homogeneous reactors. • Application for coupled calculations of the Molten Salt Fast Reactor. • Load following, over-cooling and reactivity insertion transient studies. • Validation of the reactor intrinsic stability for normal and accidental transients. - Abstract: In this paper we present transient studies of the Molten Salt Fast Reactor (MSFR). This generation IV reactor is characterized by a liquid fuel circulating in the core cavity, requiring specific simulation tools. An innovative neutronic approach called “Transient Fission Matrix” is used to perform spatial kinetic calculations with a reduced computational cost through a pre-calculation of the Monte Carlo spatial and temporal response of the system. Coupled to this neutronic approach, the Computational Fluid Dynamics code OpenFOAM is used to model the complex flow pattern in the core. An accurate interpolation model developed to take into account the thermal hydraulics feedback on the neutronics including reactivity and neutron flux variation is presented. Finally different transient studies of the reactor in normal and accidental operating conditions are detailed such as reactivity insertion and load following capacities. The results of these studies illustrate the excellent behavior of the MSFR during such transients.

  9. Energetic and metabolic transient response of Saccharomyces cerevisiae to benzoic acid.

    Science.gov (United States)

    Kresnowati, M T A P; van Winden, W A; van Gulik, W M; Heijnen, J J

    2008-11-01

    Saccharomyces cerevisiae is known to be able to adapt to the presence of the commonly used food preservative benzoic acid with a large energy expenditure. Some mechanisms for the adaptation process have been suggested, but its quantitative energetic and metabolic aspects have rarely been discussed. This study discusses use of the stimulus response approach to quantitatively study the energetic and metabolic aspects of the transient adaptation of S. cerevisiae to a shift in benzoic acid concentration, from 0 to 0.8 mM. The information obtained also serves as the basis for further utilization of benzoic acid as a tool for targeted perturbation of the energy system, which is important in studying the kinetics and regulation of central carbon metabolism in S. cerevisiae. Using this experimental set-up, we found significant fast-transient (< 3000 s) increases in O(2) consumption and CO(2) production rates, of approximately 50%, which reflect a high energy requirement for the adaptation process. We also found that with a longer exposure time to benzoic acid, S. cerevisiae decreases the cell membrane permeability for this weak acid by a factor of 10 and decreases the cell size to approximately 80% of the initial value. The intracellular metabolite profile in the new steady-state indicates increases in the glycolytic and tricarboxylic acid cycle fluxes, which are in agreement with the observed increases in specific glucose and O(2) uptake rates.

  10. How Language Supports Adaptive Teaching through a Responsive Learning Culture

    Science.gov (United States)

    Johnston, Peter; Dozier, Cheryl; Smit, Julie

    2016-01-01

    For students to learn optimally, teachers must design classrooms that are responsive to the full range of student development. The teacher must be adaptive, but so must each student and the learning culture itself. In other words, adaptive teaching means constructing a responsive learning culture that accommodates and even capitalizes on diversity…

  11. A simplified model for equilibrium and transient swelling of thermo-responsive gels.

    Science.gov (United States)

    Drozdov, A D; deClaville Christiansen, J

    2017-11-01

    A simplified model is developed for the elastic response of thermo-responsive gels subjected to swelling under an arbitrary deformation with finite strains. The constitutive equations involve five adjustable parameters that are determined by fitting observations in equilibrium water uptake tests and T-jump transient tests on thin gel disks. Two scenarios for water release under heating are revealed by means of numerical simulation. When the final temperature in a T-jump test is below the volume-phase transition temperature, deswelling is characterized by smooth distribution of water molecules and small tensile stresses. When the final temperature exceeds the critical temperature, a gel disk is split into three regions (central part with a high concentration of water molecules and two domains near the boundaries with low water content) separated by sharp interfaces, whose propagation is accompanied by development of large (comparable with the elastic modulus) tensile stresses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Gamma-ray transients and related astrophysical phenomena

    International Nuclear Information System (INIS)

    Lingenfelter, R.E.; Hudson, H.S.; Worrall, D.M.

    1982-01-01

    The workshop covered the study of the explosive phenomena responsible for the various gamma ray transients. X-ray burster observations and theories were also reviewed with emphasis on their relationship to gamma ray bursts. Recent observational data, particularly from the SMM, HEAO, and VENERA satellites made the workshop especially timely. Major headings include: gamma-ray transients, x-ray bursts, solar transients, and instrumental concepts. Individual items from the workshop were prepared separately for the data base

  13. A Hierarchical Method for Transient Stability Prediction of Power Systems Using the Confidence of a SVM-Based Ensemble Classifier

    Directory of Open Access Journals (Sweden)

    Yanzhen Zhou

    2016-09-01

    Full Text Available Machine learning techniques have been widely used in transient stability prediction of power systems. When using the post-fault dynamic responses, it is difficult to draw a definite conclusion about how long the duration of response data used should be in order to balance the accuracy and speed. Besides, previous studies have the problem of lacking consideration for the confidence level. To solve these problems, a hierarchical method for transient stability prediction based on the confidence of ensemble classifier using multiple support vector machines (SVMs is proposed. Firstly, multiple datasets are generated by bootstrap sampling, then features are randomly picked up to compress the datasets. Secondly, the confidence indices are defined and multiple SVMs are built based on these generated datasets. By synthesizing the probabilistic outputs of multiple SVMs, the prediction results and confidence of the ensemble classifier will be obtained. Finally, different ensemble classifiers with different response times are built to construct different layers of the proposed hierarchical scheme. The simulation results show that the proposed hierarchical method can balance the accuracy and rapidity of the transient stability prediction. Moreover, the hierarchical method can reduce the misjudgments of unstable instances and cooperate with the time domain simulation to insure the security and stability of power systems.

  14. Experimental studies on thermal hydraulic responses for transient operations of the SMART-P

    International Nuclear Information System (INIS)

    Choi, K.Y.; Park, H.S.; Cho, S.; Park, C.K.; Lee, S.J.; Song, C.H.; Chung, M.K.

    2005-01-01

    Full text of publication follows: Thermal hydraulic responses for transient operations of the SMART-P are experimentally investigated by using a integral effect test facility. This test facility (VISTA) has been constructed to simulate the SMART-P, which is a pilot plant of the SMART. The SMART-P is an advanced modular integral type pressurized water reactor (65 MWt) whose major RCS components, such as main coolant pumps, helical-coiled tube bundle steam generators and pressurizers, are contained in a reactor vessel. This integral design approach eliminates the large coolant loop piping, thus eliminates the occurrence of a large break LOCA. Passive Residual Heat Removal System (PRHRS) is installed to prevent overheating and over-pressurization of the primary system during accidental conditions. The PRHRS of the SMART-P removes the core decay heat by natural circulation of the two-phase fluid. The VISTA facility is a full height and 1/96 volume scaled test facility with respect to the SMART-P and will be used to understand the thermal-hydraulic responses following transients and finally to verify the system design of the SMART-P. The experimental data from the VISTA facility will be essential to system designers to resolve open issues relevant to the design of the SMART-P. The full functional control logics are implanted into the VISTA facility to cope with abnormal transients. The core of the facility can be selectively controlled by either a T-control or a T+N control method. The T-control method is a control method to adjust the core power according to the core exit coolant temperature and is designed to be used for high primary coolant flow conditions. On the other hand, the T+N control method is for low primary coolant flow conditions and it uses core exit temperature as well as core power itself as control inputs. The thermal hydraulic responses are carefully investigated according to different core control methods. Several experiments have been performed to

  15. Learning Social Responsibility in Schools: A Restorative Practice

    Science.gov (United States)

    Macready, Tom

    2009-01-01

    Vygotsky regarded the site of learning to be within a matrix of relational action. From this perspective, learning social responsibility will involve a focus on the learning environments that are made available in schools. Adapting the concept of restorative justice to a school context, restorative practice offers a range of relevant learning…

  16. HECTR [Hydrogen Event: Containment Transient Response] analyses of the Nevada Test Site (NTS) premixed combustion experiments

    International Nuclear Information System (INIS)

    Wong, C.C.

    1988-11-01

    The HECTR (Hydrogen Event: Containment Transient Response) computer code has been developed at Sandia National Laboratories to predict the transient pressure and temperature responses within reactor containments for hypothetical accidents involving the transport and combustion of hydrogen. Although HECTR was designed primarily to investigate these phenomena in LWRs, it may also be used to analyze hydrogen transport and combustion experiments as well. It is in this manner that HECTR is assessed and empirical correlations, such as the combustion completeness and flame speed correlations for the hydrogen combustion model, if necessary, are upgraded. In this report, we present HECTR analyses of the large-scale premixed hydrogen combustion experiments at the Nevada Test Site (NTS) and comparison with the test results. The existing correlations in HECTR version 1.0, under certain conditions, have difficulty in predicting accurately the combustion completeness and burn time for the NTS experiments. By combining the combustion data obtained from the NTS experiments with other experimental data (FITS, VGES, ACUREX, and Whiteshell), a set of new and better combustion correlations was generated. HECTR prediction of the containment responses, using a single-compartment model and EPRI-provided combustion completeness and burn time, compares reasonably well against the test results. However, HECTR prediction of the containment responses using a multicompartment model does not compare well with the test results. This discrepancy shows the deficiency of the homogeneous burning model used in HECTR. To overcome this deficiency, a flame propagation model is highly recommended. 16 refs., 84 figs., 5 tabs

  17. Transient lower esophageal sphincter relaxation and esophageal motor response.

    Science.gov (United States)

    Schneider, Joachim H; Küper, Markus A; Königsrainer, Alfred; Brücher, Björn L D M

    2010-04-01

    Gastroesophageal reflux is caused by transient lower esophageal sphincter relaxations (TLESRs) in healthy individuals and in most patients with gastroesophageal reflux disease (GERD). Refluxate is normally propelled by pharyngeally induced swallowing events, but TLESRs may also be accompanied by retrograde esophageal motor responses (EMRs). These contractions have not previously been investigated and their effect on esophageal clearance is not known. The aim of this study was to assess the frequency of EMRs after TLESR in healthy individuals and GERD patients and to develop an animal model for further investigation of EMRs. The frequency of TLESRs and esophageal body contractions after TLESRs was assessed using ambulatory manometry in five healthy individuals and five GERD patients. An animal model was developed for reproducible provocation of TLESRs and subsequent EMRs. Patients with GERD have significantly more TLESRs than healthy individuals. However, post-TLESR EMRs were not more frequent in the GERD group. All post-TLESR EMRs presented as simultaneous contractions of the esophagus. The feline model allowed reproducible initiation of the esophageal motor response after TLESR, showing that EMRs can be induced by external mechanoreceptor stimulation simultaneously with LES relaxation. This experimental design imitates the conditions after fundoplication in humans. The study demonstrated that GERD patients have significantly more TLESRs in comparison with healthy individuals, but these were only incidental to EMRs. Further research is needed to improve our understanding of esophageal motility disorders. The animal model presented offers a feasible tool for investigating TLESR-induced esophageal motility.

  18. Transient response of a polymer electrolyte membrane fuel cell subjected to time-varying modulating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Noorani, S.; Shamim, T. [Michigan-Dearborn Univ., Dearborn, MI (United States). Dept. of Mechanical Engineering

    2009-07-01

    In order for fuel cells to compete with internal combustion engines, they must have significant advantages in terms of overall efficiency, weight, packaging, safety and cost. A key requirement is its ability to operate under highly transient conditions during start-up, acceleration, and deceleration with stable performance. Therefore, a better understanding of fuel cell dynamic behaviour is needed along with better water management and distributions inside the cell. Therefore, this study investigated the effect of transient conditions on water distribution inside a polymer electrolyte membrane (PEM) cell. A macroscopic single-fuel cell based, one-dimensional, isothermal mathematical model was used to study the effect of modulating cell voltage on the water distribution of anode, cathode, catalyst layers, and membrane. Compared to other existing models, this model did not rely on the non-physical assumption of the uptake curve equilibrium between the pore vapour and ionomer water in the catalyst layers. Instead, the transition between the two phases was modeled as a finite-rate equilibration process. The modulating conditions were simulated by forcing the temporal variations in fuel cell voltage. The results revealed that cell voltage modulations cause a departure in the cell behaviour from its steady behaviour, and the finite-rate equilibration between the catalyst vapour and liquid water can be a factor in determining the cell response. The cell response is also affected by the modulating frequency and amplitude. The peak cell response was observed at low frequencies. Keywords: fuel cell, water transport, dynamic behaviour, numerical simulations. 9 refs., 1 tab., 5 figs.

  19. The transient transpiration heat flux meter

    International Nuclear Information System (INIS)

    Martins, N.; Calisto, H.; Afgan, N.; Leontiev, A.I.

    2006-01-01

    A new heat flux measurement principle, based on the transient response of a transpiration radiometer, is proposed. The measurement principle of current transpiration radiometers is based on a steady-state temperature measurement in a porous element. Since it may typically take several seconds to reach these conditions, there are obvious benefits in reducing the instrument response time. This can be achieved through the analysis of its transient response in order to predict the incident heat flux. In addition, the proposed methodology enables the separate measurement of the radiative and convective components of incident heat fluxes, without compromising the known advantages of transpiration radiometers. The availability of such an instrument may enable the development of advanced monitoring, diagnostic and control systems for thermal equipment

  20. Transient and stationary eddies in differing GCM climates

    International Nuclear Information System (INIS)

    Hall, N.M.J.; Valdes, P.J.

    1994-01-01

    The response of transients to changing forcing/boundary conditions can be just as striking as the response of mean fields such as surface temperature. Indeed the two are intimately linked and the extent to which the transients are either controlled by, or shape the mean flow is difficult to quantify. Diagnostics are presented from several GCM equilibrium climate simulations using the UGAMP GCM. These include representations of the present climate: The Last Glacial Maximum and the Jurassic climate (150 M years ago). Changes in the distribution of transient eddy activity are compared with changes in low level baroclinicity to assess the direct response of the storm tracks to local conditions. Budget calculations are also presented to identify the changing roles of different components of the atmospheric circulation in transporting heat and moisture from equator to pole

  1. Occlusal Disharmony Transiently Impairs Learning and Memory in the Mouse by Increasing Dynorphin A Levels in the Amygdala.

    Science.gov (United States)

    Yamada, Kentaro; Ono, Yumie; Kubo, Kin-Ya; Yamamoto, Toshiharu; Onozuka, Minoru

    2013-05-01

    Occlusal disharmony sometimes causes not only stiffness of neck but also psychiatric depression, suggesting that the condition of oral cavity may affect the central nervous system. Dynorphin A is an endogenous opioid peptide that specifically binds the κ-opioid receptor and has a protective role against stress. Dynorphinergic nervous system is intensely distributed in the amygdala and hippocampus that are coping areas with stress. As a model of malocclusion, we placed dental resin on the molars to increase the occlusal vertical dimension (bite-raise). After various survival times, we analyzed the amygdala and hippocampus by immunohistochemistry and immunosorbent assay (ELISA). Furthermore, the effects on learning and memory were assessed by Morris water maze test. In the amygdala, the levels of dynorphin A were increased on the 1st day after increasing the vertical dimension as indicated by immunohistochemical and ELISA assessments. The levels of dynorphin A returned to control levels on the 5th day. In the hippocampus, there were no noticeable changes in dynorphin A levels. The water maze test indicated that increasing the vertical dimension caused longer escape latency times on the 3rd day compared to those of sham-operated group. However, the bite-raised mice treated with a dynorphin antagonist, nor-binaltorphimine, showed similar escape latency times to the times of sham-operated group, even on the 3rd day. These results suggest that occlusal disharmony causes stress resulting in a transient increase of dynorphin A levels at least in the amygdala and that the increased dynorphin A levels transiently impair learning and memory.

  2. Exploring Practical Responses of M3LC for Learning Literacy

    Science.gov (United States)

    Nasrullah; Baharman

    2018-01-01

    This study aims to explore the responses of participants toward Mathematics-Language Literacy Learning Courseware (M3LC) for learning literacy. There are five practical aspects concerned by involving 30 participants in the focus group discussion. In the beginning, participants were given some response sheet and introduced to M3LC by watching learning video of M3LC. At the end, they were asked to concern about response sheet and give comments related what they saw during the introduction session. The results show that the responses of users’ agree and strongly agree are still higher than those of users’ disagree or strongly disagree, with below 30% of responses are in the fair category. It means that the participants tend to give a positive opinion that M3LC is a useful courseware since it is qualified to satisfy 5 practical aspects, including knowledge use, knowledge construction, evaluation practice, social programming, and valuing to support literacy learning. In future, the implementation of using this courseware can be enhanced to further recognition of literacy level so that students can be well-prepared before starting learning activities in the classroom.

  3. Place and Response Learning in the Open-field Tower Maze.

    Science.gov (United States)

    Lipatova, Olga; Campolattaro, Matthew M; Toufexis, Donna J; Mabry, Erin A

    2015-10-28

    This protocol describes how the Open-field Tower Maze (OFTM) paradigm is used to study spatial learning in rodents. This maze is especially useful for examining how rats learn to use a place- or response-learning to successfully navigate in an open-field arena. Additionally, this protocol describes how the OFTM differs from other behavioral maze paradigms that are commonly used to study spatial learning in rodents. The OFTM described in this article was adapted from the one previously described by Cole, Clipperton, and Walt (2007). Specifically, the OFTM was created to test spatial learning in rodents without the experimenter having to consider how "stress" might play a role as a confounding variable. Experiments have shown that stress-alone can significantly affect cognitive function(1). The representative results section contains data from an experiment that used the OFTM to examine the effects of estradiol treatment on place- and response-learning in adult female Sprague Dawley rats(2). Future studies will be designed to examine the role of the hippocampus and striatum in place- and response-learning in the OFTM.

  4. Comparing and characterizing transient and steady-state tests of the peripheral chemoreflex in humans.

    Science.gov (United States)

    Pfoh, Jamie R; Tymko, Michael M; Abrosimova, Maria; Boulet, Lindsey M; Foster, Glen E; Bain, Anthony R; Ainslie, Philip N; Steinback, Craig D; Bruce, Christina D; Day, Trevor A

    2016-03-01

    What is the central question of this study? We aimed to characterize the cardiorespiratory and cerebrovascular responses to transient and steady-state tests of the peripheral chemoreflex and to compare the hypoxic ventilatory responses (HVRs) between these tests. What is the main finding and its importance? The cardiovascular and cerebrovascular responses to transient tests were small in magnitude and short in duration. The steady-state isocapnic hypoxia test elicited a larger HVR than the transient 100% N(2) test, but the response magnitudes were correlated within individuals. The transient test of the HVR elicits fewer systemic effects than steady-state techniques and may have greater experimental utility than previously appreciated. Carotid chemoreceptors detect changes in arterial PO(2) and PCO(2), eliciting a peripheral chemoreflex (PCR). Steady-state (SS) hypoxia tests using dynamic end-tidal forcing (DEF) have been used to assess the hypoxic ventilatory response (HVR) but may be confounded by concomitant systemic effects. Transient tests of the PCR have also been developed but are not widely used, nor have the cardiovascular and cerebrovascular responses been characterized. We characterized the cardiorespiratory and cerebrovascular responses to transient tests of the PCR and compared the HVR between transient and SS-DEF tests. We hypothesized that the cardiovascular and cerebrovascular responses to the transient tests would be minimal and that the respiratory responses elicited from the transient and SS-DEF tests would be different in magnitude and not well correlated within individuals. Participants underwent five consecutive trials of two transient tests [three-breath 100% N(2) (TT-N(2)) and a single-breath 13% CO(2), in air] and two 10 min SS-DEF tests [isocapnic (SS-ISO) and poikilocapnic (SS-POI) hypoxia]. In response to the transient tests, heart rate, mean arterial pressure and the middle and posterior cerebral artery blood velocity increased (all P

  5. Evidence of Hierarchy in the Complex Fractured System of Geropotamos (Crete, Greece), as Extracted from Transient Electromagnetic Responses

    Science.gov (United States)

    Vallianatos, Filippos; Kouli, Maria; Kalisperi, Despina

    2018-03-01

    The essential goals of this paper are to test the transient electromagnetic (TEM) response in a fractured geological complex medium and to better understand the physics introduced by associating a roughness parameter β to the geological formation. An anomalous fractional diffusion approach is incorporated to describe the electromagnetic induction in rough multi-scaled geological structures. The multi-scaling characteristics of Geropotamos basin in Crete are revealed through the analysis of transient step-off response of an EM loop antenna. The semi-empirical parameters derived from late-time TEM measurements are correlated with the multi-scale heterogeneities of the medium. Certain interesting properties of the late-time slope γ(β) and the power law of near surface resistivity distribution, as extracted from TEM inversion for different depth, are presented. The analysis of the parameter γ(β) which scales the induced voltage in the loop in the late stage of the electromagnetic response leads to a different view of the EM geophysical data interpretation. We show that it is strongly correlated with areas of high fracture density within the geological formations of the Geropotamos area. For that reason, it is proposed as a local multi-scaling empirical index. The results of this paper suggest that anomalous diffusion could be a viable physical mechanism for the fractal transport of charge carriers, explaining observed late-time TEM responses across a variety of natural geological settings.

  6. Heavy Ion Microbeam- and Broadbeam-Induced Current Transients in SiGe HBTs

    Science.gov (United States)

    Pellish, Jonathan A.; Reed, R. A.; McMorrow, D.; Vizkelethy, G.; Ferlet-Cavrois, V.; Baggio, J.; Duhamel, O.; Moen, K. A.; Phillips, S. D.; Diestelhorst, R. M.; hide

    2009-01-01

    IBM 5AM SiGe HBT is device-under-test. High-speed measurement setup. Low-impedance current transient measurements. SNL, JYFL, GANIL. Microbeam to broadbeam position inference. Improvement to state-of-the-art. Microbeam (SNL) transients reveal position dependent heavy ion response, Unique response for different device regions Unique response for different bias schemes. Similarities to TPA pulsed-laser data. Broadbeam transients (JYFL and GANIL) provide realistic heavy ion response. Feedback using microbeam data. Overcome issues of LET and ion range with microbeam. **Angled Ar-40 data in full paper. Data sets yield first-order results, suitable for TCAD calibration feedback.

  7. Advanced Instrumentation for Transient Reactor Testing

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, Michael L.; Anderson, Mark; Imel, George; Blue, Tom; Roberts, Jeremy; Davis, Kurt

    2018-01-31

    Transient testing involves placing fuel or material into the core of specialized materials test reactors that are capable of simulating a range of design basis accidents, including reactivity insertion accidents, that require the reactor produce short bursts of intense highpower neutron flux and gamma radiation. Testing fuel behavior in a prototypic neutron environment under high-power, accident-simulation conditions is a key step in licensing nuclear fuels for use in existing and future nuclear power plants. Transient testing of nuclear fuels is needed to develop and prove the safety basis for advanced reactors and fuels. In addition, modern fuel development and design increasingly relies on modeling and simulation efforts that must be informed and validated using specially designed material performance separate effects studies. These studies will require experimental facilities that are able to support variable scale, highly instrumented tests providing data that have appropriate spatial and temporal resolution. Finally, there are efforts now underway to develop advanced light water reactor (LWR) fuels with enhanced performance and accident tolerance. These advanced reactor designs will also require new fuel types. These new fuels need to be tested in a controlled environment in order to learn how they respond to accident conditions. For these applications, transient reactor testing is needed to help design fuels with improved performance. In order to maximize the value of transient testing, there is a need for in-situ transient realtime imaging technology (e.g., the neutron detection and imaging system like the hodoscope) to see fuel motion during rapid transient excursions with a higher degree of spatial and temporal resolution and accuracy. There also exists a need for new small, compact local sensors and instrumentation that are capable of collecting data during transients (e.g., local displacements, temperatures, thermal conductivity, neutron flux, etc.).

  8. Structural Plasticity Denoises Responses and Improves Learning Speed

    Directory of Open Access Journals (Sweden)

    Robin Spiess

    2016-09-01

    Full Text Available Despite an abundance of computational models for learning of synaptic weights, there has been relatively little research on structural plasticity, i.e. the creation and elimination of synapses. Especially, it is not clear how structural plasticity works in concert with spike-timing-dependent plasticity (STDP and what advantages their combination offers.Here we present a fairly large-scale functional model that uses leaky integrate-and-fire neurons, STDP, homeostasis, recurrent connections, and structural plasticity to learn the input encoding, the relation between inputs, and to infer missing inputs. Using this model, we compare the error and the amount of noise in the network's responses with and without structural plasticity and the influence of structural plasticity on the learning speed of the network.Using structural plasticity during learning shows good results for learning the representation of input values, i.e. structural plasticity strongly reduces the noise of the response by preventing spikes with a high error.For inferring missing inputs we see similar results, with responses having less noise if the network was trained using structural plasticity.Additionally, using structural plasticity with pruning significantly decreased the time to learn weights suitable for inference.Presumably, this is due to the clearer signal containing less spikes that misrepresent the desired value. Therefore, this work shows that structural plasticity is not only able to improve upon the performance using STDP without structural plasticity but also speeds up learning.Additionally, it addresses the practical problem of limited resources for connectivity that is not only apparent in the mammalian neocortex but also in computer hardware or neuromorphic (brain-inspired hardware by efficiently pruning synapses without losing performance.

  9. VO2 OFF TRANSIENT KINETICS IN EXTREME INTENSITY SWIMMING

    Directory of Open Access Journals (Sweden)

    Ana Sousa

    2011-09-01

    Full Text Available Inconsistencies about dynamic asymmetry between the on- and off- transient responses in oxygen uptake are found in the literature. Therefore, the purpose of this study was to characterize the oxygen uptake off-transient kinetics during a maximal 200-m front crawl effort, as examining the degree to which the on/off regularity of the oxygen uptake kinetics response was preserved. Eight high level male swimmers performed a 200-m front crawl at maximal speed during which oxygen uptake was directly measured through breath-by-breath oxymetry (averaged every 5 s. This apparatus was connected to the swimmer by a low hydrodynamic resistance respiratory snorkel and valve system. Results: The on- and off-transient phases were symmetrical in shape (mirror image once they were adequately fitted by a single-exponential regression models, and no slow component for the oxygen uptake response was developed. Mean (± SD peak oxygen uptake was 69.0 (± 6.3 mL·kg-1·min-1, significantly correlated with time constant of the off- transient period (r = 0.76, p < 0.05 but not with any of the other oxygen off-transient kinetic parameters studied. A direct relationship between time constant of the off-transient period and mean swimming speed of the 200-m (r = 0.77, p < 0.05, and with the amplitude of the fast component of the effort period (r = 0.72, p < 0.05 were observed. The mean amplitude and time constant of the off-transient period values were significantly greater than the respective on- transient. In conclusion, although an asymmetry between the on- and off kinetic parameters was verified, both the 200-m effort and the respectively recovery period were better characterized by a single exponential regression model

  10. Modeling of environmentally induced transients within satellites

    Science.gov (United States)

    Stevens, N. John; Barbay, Gordon J.; Jones, Michael R.; Viswanathan, R.

    1987-01-01

    A technique is described that allows an estimation of possible spacecraft charging hazards. This technique, called SCREENS (spacecraft response to environments of space), utilizes the NASA charging analyzer program (NASCAP) to estimate the electrical stress locations and the charge stored in the dielectric coatings due to spacecraft encounter with a geomagnetic substorm environment. This information can then be used to determine the response of the spacecraft electrical system to a surface discharge by means of lumped element models. The coupling into the electronics is assumed to be due to magnetic linkage from the transient currents flowing as a result of the discharge transient. The behavior of a spinning spacecraft encountering a severe substorm is predicted using this technique. It is found that systems are potentially vulnerable to upset if transient signals enter through the ground lines.

  11. Differentiating Visual from Response Sequencing during Long-term Skill Learning.

    Science.gov (United States)

    Lynch, Brighid; Beukema, Patrick; Verstynen, Timothy

    2017-01-01

    The dual-system model of sequence learning posits that during early learning there is an advantage for encoding sequences in sensory frames; however, it remains unclear whether this advantage extends to long-term consolidation. Using the serial RT task, we set out to distinguish the dynamics of learning sequential orders of visual cues from learning sequential responses. On each day, most participants learned a new mapping between a set of symbolic cues and responses made with one of four fingers, after which they were exposed to trial blocks of either randomly ordered cues or deterministic ordered cues (12-item sequence). Participants were randomly assigned to one of four groups (n = 15 per group): Visual sequences (same sequence of visual cues across training days), Response sequences (same order of key presses across training days), Combined (same serial order of cues and responses on all training days), and a Control group (a novel sequence each training day). Across 5 days of training, sequence-specific measures of response speed and accuracy improved faster in the Visual group than any of the other three groups, despite no group differences in explicit awareness of the sequence. The two groups that were exposed to the same visual sequence across days showed a marginal improvement in response binding that was not found in the other groups. These results indicate that there is an advantage, in terms of rate of consolidation across multiple days of training, for learning sequences of actions in a sensory representational space, rather than as motoric representations.

  12. RETRAN sensitivity studies of light water reactor transients. Final report

    International Nuclear Information System (INIS)

    Burrell, N.S.; Gose, G.C.; Harrison, J.F.; Sawtelle, G.R.

    1977-06-01

    This report presents the results of sensitivity studies performed using the RETRAN/RELAP4 transient analysis code to identify critical parameters and models which influence light water reactor transient predictions. Various plant transients for both boiling water reactors and pressurized water reactors are examined. These studies represent the first detailed evaluation of the RETRAN/RELAP4 transient code capability in predicting a variety of plant transient responses. The wide range of transients analyzed in conjunction with the parameter and modeling studies performed identify several sensitive areas as well as areas requiring future study and model development

  13. Studies on an Electromagnetic Transient Model of Offshore Wind Turbines and Lightning Transient Overvoltage Considering Lightning Channel Wave Impedance

    Directory of Open Access Journals (Sweden)

    Li Zhang

    2017-12-01

    Full Text Available In recent years, with the rapid development of offshore wind turbines (WTs, the problem of lightning strikes has become more and more prominent. In order to reduce the failure rate caused by the transient overvoltage of lightning struck offshore WTs, the influencing factors and the response rules of transient overvoltage are analyzed. In this paper, a new integrated electromagnetic transient model of offshore WTs is established by using the numerical calculation method of the electromagnetic field first. Then, based on the lightning model and considering the impedance of the lightning channel, the transient overvoltage of lightning is analyzed. Last, the electromagnetic transient model of offshore WTs is simulated and analyzed by using the alternative transients program electro-magnetic transient program (ATP-EMTP software. The influence factors of lightning transient overvoltage are studied. The main influencing factors include the sea depth, the blade length, the tower height, the lightning flow parameters, the lightning strike point, and the blade rotation position. The simulation results show that the influencing factors mentioned above have different effects on the lightning transient overvoltage. The results of the study have some guiding significance for the design of the lightning protection of the engine room.

  14. Transient analysis for PWR reactor core using neural networks predictors

    International Nuclear Information System (INIS)

    Gueray, B.S.

    2001-01-01

    In this study, transient analysis for a Pressurized Water Reactor core has been performed. A lumped parameter approximation is preferred for that purpose, to describe the reactor core together with mechanism which play an important role in dynamic analysis. The dynamic behavior of the reactor core during transients is analyzed considering the transient initiating events, wich are an essential part of Safety Analysis Reports. several transients are simulated based on the employed core model. Simulation results are in accord the physical expectations. A neural network is developed to predict the future response of the reactor core, in advance. The neural network is trained using the simulation results of a number of representative transients. Structure of the neural network is optimized by proper selection of transfer functions for the neurons. Trained neural network is used to predict the future responses following an early observation of the changes in system variables. Estimated behaviour using the neural network is in good agreement with the simulation results for various for types of transients. Results of this study indicate that the designed neural network can be used as an estimator of the time dependent behavior of the reactor core under transient conditions

  15. Transient response of rotating laminated functionally graded cylindrical shells in thermal environment

    International Nuclear Information System (INIS)

    Malekzadeh, P.; Heydarpour, Y.; Haghighi, M.R. Golbahar; Vaghefi, M.

    2012-01-01

    Based on the elasticity theory, the transient analysis of dynamically pressurized rotating multi-layered functionally graded (FG) cylindrical shells in thermal environment is presented. The variations of the field variables across the shell thickness are accurately modeled by dividing the shell into a set of co-axial mathematical layers in the radial direction. The initial thermo-mechanical stresses are obtained by solving the thermoelastic equilibrium equations. The differential quadrature method and Newmark's time integration scheme are employed to discretize the obtained governing equations of each mathematical layer. After performing the convergence and comparison studies, parametric studies for two common types of FG sandwich shells, namely, the shell with homogeneous inner/outer layers and FG core and the shell with FG inner/outer layers and homogeneous core are carried out. The influences of the temperature dependence of material properties, material graded index, the convective heat transfer coefficient, the angular velocity, the boundary condition and the geometrical parameters (length and thickness to outer radius ratios) on the dynamic response of the FG shells are investigated. Highlights: ► As a first endeavor, transient analysis of rotating laminated functionally graded cylinders. ► Employing an elasticity based discrete layer-differential quadrature method. ► Evaluating and including the initial thermo-mechanical stresses accurately. ► Considering the temperature-dependence of the material properties. ► Presenting some new results, which can be used as benchmark solution for future works.

  16. Transient analysis of DTT rakes

    International Nuclear Information System (INIS)

    Kamath, P.S.; Lahey, R.T. Jr.

    1981-01-01

    This paper presents an analytical model for the determination of the cross-sectionally averaged transient mass flux of a two-phase fluid flowing in a conduit instrumented by a Drag-Disk Turbine Transducer (DTT) Rake and a multibeam gamma densitometer. Parametric studies indicate that for a typical blowdown transient, dynamic effects such as rotor inertia can be important for the turbine-meter. In contrast, for the drag-disk, a frequency response analysis showed that the quasisteady solution is valid below a forcing frequency of about 10 Hz, which is faster than the time scale normally encountered during blowdowns. The model showed reasonably good agreement with full scale transient rake data, where the flow regimes were mostly homogeneous or stratified, thus indicating that the model is suitable for the analysis of a DTT rake. (orig.)

  17. Transient hardened power FETs

    International Nuclear Information System (INIS)

    Dawes, W.R. Jr.; Fischer, T.A.; Huang, C.C.C.; Meyer, W.J.; Smith, C.S.; Blanchard, R.A.; Fortier, T.J.

    1986-01-01

    N-channel power FETs offer significant advantages in power conditioning circuits. Similiarily to all MOS technologies, power FET devices are vulnerable to ionizing radiation, and are particularily susceptible to burn-out in high dose rate irradiations (>1E10 rads(Si)/sec.), which precludes their use in many military environments. This paper will summarize the physical mechanisms responsible for burn-out, and discuss various fabrication techniques designed to improve the transient hardness of power FETs. Power FET devices were fabricated with several of these techniques, and data will be presented which demonstrates that transient hardness levels in excess of 1E12 rads(Si)/sec. are easily achievable

  18. Simulation of Transient Response of Ir-TES for Position-Sensitive TES with Waveform Domain Multiplexing

    Science.gov (United States)

    Minamikawa, Y.; Sato, H.; Mori, F.; Damayanthi, R. M. T.; Takahashi, H.; Ohno, M.

    2008-04-01

    We are developing a new x-ray microcalorimeter based on a superconducting transition edge sensor (TES) as an imaging sensor. Our measurement shows unique waveforms which we consider as an expression of thermal nonuniformity of TES films. This arises from the different thermal responses, so that response signal shapes would vary according to the position of the incident x-ray. This position dependency deteriorate the measured energy resolution, but with appropriate waveform analysis, this would be useful for imaging device. For more inspection, we have developed a simulation code which enables a dynamic simulation to obtain a transient response of the TES by finite differential method. Temperature and electric current distributions are calculated. As a result, we successfully obtained waveform signals. The calculated signal waveforms have similar characteristics to the measured signals. This simulation visualized the transition state of the device and will help to design better detector.

  19. Transient particle emission measurement with optical techniques

    Science.gov (United States)

    Bermúdez, Vicente; Luján, José M.; Serrano, José R.; Pla, Benjamín

    2008-06-01

    Particulate matter is responsible for some respiratory and cardiovascular diseases. In addition, it is one of the most important pollutants of high-speed direct injection (HSDI) passenger car engines. Current legislation requires particulate dilution tunnels for particulate matter measuring. However for development work, dilution tunnels are expensive and sometimes not useful since they are not able to quantify real-time particulate emissions during transient operation. In this study, the use of a continuous measurement opacimeter and a fast response HFID is proven to be a good alternative to obtain instantaneous particle mass emissions during transient operation (due to particulate matter consisting mainly of soot and SOF). Some methods and correlations available from literature, but developed for steady conditions, are evaluated during transient operation by comparing with mini-tunnel measurements during the entire MVEG-A transient cycle. A new correlation was also derived from this evaluation. Results for soot and SOF (obtained from the new correlation proposed) are compared with soot and SOF captured with particulate filters, which have been separated by means of an SOF extraction method. Finally, as an example of ECU design strategies using these sort of correlations, the EGR valve opening is optimized during transient operation. The optimization is performed while simultaneously taking into account instantaneous fuel consumption, particulate emissions (calculated with the proposed correlation) and other regulated engine pollutants.

  20. Learning in clinical practice: Stimulating and discouraging response to social comparison.

    Science.gov (United States)

    Raat, Janet; Kuks, Jan; Cohen-Schotanus, Janke

    2010-01-01

    Social comparison theory is relevant for learning in general. In a clinical context, we examined four hypotheses concerning: preferred other to compare with, preferred direction of comparison, response to social comparison and influence of personal social comparison orientation (SCO). To investigate the relevance of social comparison for clinical workplace learning. Students (n = 437) from nine different hospitals completed two questionnaires measuring their SCO and the direction of and response to their comparisons. t-tests were used to analyse the data. Students substantially did compare. They preferred to compare with peer students more than with residents or staff, and with peers doing better more than with peers doing worse. Their response to social comparison was more often stimulating for learning than discouraging. Students high in SCO reported a stronger stimulating and discouraging response to their comparisons than students low in SCO. Social comparison does play a role in clinical workplace learning. The mainly stimulating response to social comparison indicates a positive learning influence. The preferred comparison with peers emphasizes the role of peers in the learning process. Further research should focus on student comparison behaviour and on situations that strengthen the positive effects of social comparison and reduce the negative or obstructing ones.

  1. PC operated acoustic transient spectroscopy of deep levels in MIS structures

    International Nuclear Information System (INIS)

    Bury, P.; Jamnicky, I.

    1996-01-01

    A new version of acoustic deep-level transient spectroscopy is presented to study the traps at the insulator-semiconductor interface. The acoustic deep-level transient spectroscopy uses an acoustoelectric response signal produced by the MIS structure interface when a longitudinal acoustic wave propagates through a structure. The acoustoelectric response signal is extremely sensitive to external conditions of the structure and reflects any changes in the charge distribution, connected also with charged traps. In comparison with previous version of acoustic deep-level transient spectroscopy that closely coincides with the principle of the original deep-level transient spectroscopy technique, the present technique is based on the computer-evaluated isothermal transients and represents an improved, more efficient and time saving technique. Many tests on the software used for calculation as well as on experimental setup have been performed. The improved acoustic deep-level transient spectroscopy method has been applied for the Si(p) MIS structures. The deep-level parameters as activation energy and capture cross-section have been determined. (authors)

  2. Automated transient identification in the Dark Energy Survey

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, D. A. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). et al.

    2015-08-20

    We describe an algorithm for identifying point-source transients and moving objects on reference-subtracted optical images containing artifacts of processing and instrumentation. The algorithm makes use of the supervised machine learning technique known as Random Forest. We present results from its use in the Dark Energy Survey Supernova program (DES-SN), where it was trained using a sample of 898,963 signal and background events generated by the transient detection pipeline. After reprocessing the data collected during the first DES-SN observing season (2013 September through 2014 February) using the algorithm, the number of transient candidates eligible for human scanning decreased by a factor of 13.4, while only 1.0 percent of the artificial Type Ia supernovae (SNe) injected into search images to monitor survey efficiency were lost, most of which were very faint events. Here we characterize the algorithm's performance in detail, and we discuss how it can inform pipeline design decisions for future time-domain imaging surveys, such as the Large Synoptic Survey Telescope and the Zwicky Transient Facility.

  3. Image-based deep learning for classification of noise transients in gravitational wave detectors

    Science.gov (United States)

    Razzano, Massimiliano; Cuoco, Elena

    2018-05-01

    The detection of gravitational waves has inaugurated the era of gravitational astronomy and opened new avenues for the multimessenger study of cosmic sources. Thanks to their sensitivity, the Advanced LIGO and Advanced Virgo interferometers will probe a much larger volume of space and expand the capability of discovering new gravitational wave emitters. The characterization of these detectors is a primary task in order to recognize the main sources of noise and optimize the sensitivity of interferometers. Glitches are transient noise events that can impact the data quality of the interferometers and their classification is an important task for detector characterization. Deep learning techniques are a promising tool for the recognition and classification of glitches. We present a classification pipeline that exploits convolutional neural networks to classify glitches starting from their time-frequency evolution represented as images. We evaluated the classification accuracy on simulated glitches, showing that the proposed algorithm can automatically classify glitches on very fast timescales and with high accuracy, thus providing a promising tool for online detector characterization.

  4. Thermal-structural response of EBR-II major components under reactor operational transients

    International Nuclear Information System (INIS)

    Chang, L.K.; Lee, M.J.

    1983-01-01

    Until recently, the LMFBR safety research has been focused primarily on severe but highly unlikely accident, such as hypothetical-core-disruptive accidents (HCDA's), and not enough attention has been given to accident prevention, which is less severe but more likely sequence. The objective of the EBR-II operational reliability testing (ORT) is to demonstrate that the reactor can be designed and operated to prevent accident. A series of mild duty cycles and overpower transients were designed for accident prevention tests. An assessment of the EBR-II major plant components has been performed to assure structural integrity of the reactor plant for the ORT program. In this paper, the thermal-structural response and structural evaluation of the reactor vessel, the reactor-vessel cover, the intermediate heat exchanger (IHX) and the superheater are presented

  5. Early results of experiments with responsive open learning environments

    OpenAIRE

    Friedrich, M.; Wolpers, M.; Shen, R.; Ullrich, C.; Klamma, R.; Renzel, D.; Richert, A.; Heiden, B. von der

    2011-01-01

    Responsive open learning environments (ROLEs) are the next generation of personal learning environments (PLEs). While PLEs rely on the simple aggregation of existing content and services mainly using Web 2.0 technologies, ROLEs are transforming lifelong learning by introducing a new infrastructure on a global scale while dealing with existing learning management systems, institutions, and technologies. The requirements engineering process in highly populated test-beds is as important as the t...

  6. Transient Genome-Wide Transcriptional Response to Low-Dose Ionizing Radiation In Vivo in Humans

    International Nuclear Information System (INIS)

    Berglund, Susanne R.; Rocke, David M.; Dai Jian; Schwietert, Chad W.; Santana, Alison; Stern, Robin L.; Lehmann, Joerg; Hartmann Siantar, Christine L.; Goldberg, Zelanna

    2008-01-01

    Purpose: The in vivo effects of low-dose low linear energy transfer ionizing radiation on healthy human skin are largely unknown. Using a patient-based tissue acquisition protocol, we have performed a series of genomic analyses on the temporal dynamics over a 24-hour period to determine the radiation response after a single exposure of 10 cGy. Methods and Materials: RNA from each patient tissue sample was hybridized to an Affymetrix Human Genome U133 Plus 2.0 array. Data analysis was performed on selected gene groups and pathways. Results: Nineteen gene groups and seven gene pathways that had been shown to be radiation responsive were analyzed. Of these, nine gene groups showed significant transient transcriptional changes in the human tissue samples, which returned to baseline by 24 hours postexposure. Conclusions: Low doses of ionizing radiation on full-thickness human skin produce a definable temporal response out to 24 hours postexposure. Genes involved in DNA and tissue remodeling, cell cycle transition, and inflammation show statistically significant changes in expression, despite variability between patients. These data serve as a reference for the temporal dynamics of ionizing radiation response following low-dose exposure in healthy full-thickness human skin

  7. Configural Response Learning: The Acquisition of a Nonpredictive Motor Skill

    Science.gov (United States)

    Hazeltine, Eliot; Aparicio, Paul; Weinstein, Andrea; Ivry, Richard B.

    2007-01-01

    This study examined the representational nature of configural response learning using a task that required simultaneous keypresses with 2 or 3 fingers, similar to the production of chords on the piano. If the benefits of learning are related to the retrieval of individual stimulus-response mappings, performance should depend on the frequencies of…

  8. Twenty-five years of transient counting experience in French PWR units

    Energy Technology Data Exchange (ETDEWEB)

    Barthelet, B. [Electricite de France (EDF DPN), 93 - Saint-Denis (France); Savoldelli, D.; Fritz, R. [Electricite de France (EDF DPN), 93 - Noisy le Grand (France)

    2001-07-01

    For nearly twenty five years, EDF has been checking that the actual operating transients are neither more severe nor more numerous than the design basis transients. This activity of transient cycle counting and bookkeeping has enabled EDF to own a database of more than 800 reactor.years for the PWR units. The current method of transient cycle counting is presented. In the paper, we will point out the main results of transient cycle counting and lessons learned. In general, the frequencies of transients are lower than the design frequencies. In few cases, they are higher, such as the transient frequencies of the RCS lines connected to auxiliary systems often due to operating procedures or particular periodic testing. Few periodic tests were not taken into account in the design basis transient file ; they have been detected thanks to the transient cycle counting. In the last 1980's, we achieved the first updating of the design basis transient file for the PWR 900 MWe series. In the early 1990's, we updated the design basis transient file of the PWR 1300 MWe series. In fact, since design and start-up, the operating conditions have been modified (fuel cycle with stretch-out, modification of the hot leg and cold leg temperatures for the PWR 1300 MWe,...). This was the cause of many unclassified transients. In the new design basis transient file, we have created new transients and increased the frequencies of some of them. This has enabled to consider the updated design basis transient file more representative of actual operating transients. For some years, we have increasingly associated the operators with the transient cycle counting concern. We noticed progress (decreased frequencies of most transients). (authors)

  9. Twenty-five years of transient counting experience in French PWR units

    International Nuclear Information System (INIS)

    Barthelet, B.; Savoldelli, D.; Fritz, R.

    2001-01-01

    For nearly twenty five years, EDF has been checking that the actual operating transients are neither more severe nor more numerous than the design basis transients. This activity of transient cycle counting and bookkeeping has enabled EDF to own a database of more than 800 reactor.years for the PWR units. The current method of transient cycle counting is presented. In the paper, we will point out the main results of transient cycle counting and lessons learned. In general, the frequencies of transients are lower than the design frequencies. In few cases, they are higher, such as the transient frequencies of the RCS lines connected to auxiliary systems often due to operating procedures or particular periodic testing. Few periodic tests were not taken into account in the design basis transient file ; they have been detected thanks to the transient cycle counting. In the last 1980's, we achieved the first updating of the design basis transient file for the PWR 900 MWe series. In the early 1990's, we updated the design basis transient file of the PWR 1300 MWe series. In fact, since design and start-up, the operating conditions have been modified (fuel cycle with stretch-out, modification of the hot leg and cold leg temperatures for the PWR 1300 MWe,...). This was the cause of many unclassified transients. In the new design basis transient file, we have created new transients and increased the frequencies of some of them. This has enabled to consider the updated design basis transient file more representative of actual operating transients. For some years, we have increasingly associated the operators with the transient cycle counting concern. We noticed progress (decreased frequencies of most transients). (authors)

  10. Reversal learning and resurgence of operant behavior in zebrafish (Danio rerio).

    Science.gov (United States)

    Kuroda, Toshikazu; Mizutani, Yuto; Cançado, Carlos R X; Podlesnik, Christopher A

    2017-09-01

    Zebrafish are used extensively as vertebrate animal models in biomedical research for having such features as a fully sequenced genome and transparent embryo. Yet, operant-conditioning studies with this species are scarce. The present study investigated reversal learning and resurgence of operant behavior in zebrafish. A target response (approaching a sensor) was reinforced in Phase 1. In Phase 2, the target response was extinguished while reinforcing an alternative response (approaching a different sensor). In Phase 3, extinction was in effect for the target and alternative responses. Reversal learning was demonstrated when responding tracked contingency changes between Phases 1 and 2. Moreover, resurgence occurred in 10 of 13 fish in Phase 3: Target response rates increased transiently and exceeded rates of an unreinforced control response. The present study provides the first evidence with zebrafish supporting reversal learning between discrete operant responses and a laboratory model of relapse. These findings open the possibility to assessing genetic influences of operant behavior generally and in models of relapse (e.g., resurgence, renewal, reinstatement). Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Climatic feedbacks between stationary and transient eddies

    International Nuclear Information System (INIS)

    Branscome, L.E.

    1994-01-01

    Stationary eddies make a significant contribution to poleward heat transport during Northern Hemisphere winter, equaling the transport by transient eddies. On the other hand, stationary eddy transport during the summer is negligible. The effect of topography on time-mean stationary waves and low-frequency variability has been widely studied. In contrast, little attention has been given to the climatic feedbacks associated with stationary eddies. Furthermore, the relationship between stationary and transient eddies in the context of global and regional climate is not well understood. The response of the climate system to anthropogenic forcing is likely to have some dependence on stationary wave transport and its interaction with transient eddies. Some early GCM simulations and observational analyses indicate a strong feedback between the meridional heat fluxes of stationary and transient eddies

  12. Bladder cancer treatment response assessment using deep learning in CT with transfer learning

    Science.gov (United States)

    Cha, Kenny H.; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Samala, Ravi K.; Cohan, Richard H.; Caoili, Elaine M.; Paramagul, Chintana; Alva, Ajjai; Weizer, Alon Z.

    2017-03-01

    We are developing a CAD system for bladder cancer treatment response assessment in CT. We compared the performance of the deep-learning convolution neural network (DL-CNN) using different network sizes, and with and without transfer learning using natural scene images or regions of interest (ROIs) inside and outside the bladder. The DL-CNN was trained to identify responders (T0 disease) and non-responders to chemotherapy. ROIs were extracted from segmented lesions in pre- and post-treatment scans of a patient and paired to generate hybrid pre-post-treatment paired ROIs. The 87 lesions from 82 patients generated 104 temporal lesion pairs and 6,700 pre-post-treatment paired ROIs. Two-fold cross-validation and receiver operating characteristic analysis were performed and the area under the curve (AUC) was calculated for the DL-CNN estimates. The AUCs for prediction of T0 disease after treatment were 0.77+/-0.08 and 0.75+/-0.08, respectively, for the two partitions using DL-CNN without transfer learning and a small network, and were 0.74+/-0.07 and 0.74+/-0.08 with a large network. The AUCs were 0.73+/-0.08 and 0.62+/-0.08 with transfer learning using a small network pre-trained with bladder ROIs. The AUC values were 0.77+/-0.08 and 0.73+/-0.07 using the large network pre-trained with the same bladder ROIs. With transfer learning using the large network pretrained with the Canadian Institute for Advanced Research (CIFAR-10) data set, the AUCs were 0.72+/-0.06 and 0.64+/-0.09, respectively, for the two partitions. None of the differences in the methods reached statistical significance. Our study demonstrated the feasibility of using DL-CNN for the estimation of treatment response in CT. Transfer learning did not improve the treatment response estimation. The DL-CNN performed better when transfer learning with bladder images was used instead of natural scene images.

  13. Transient response of a five-region nonequilibrium real-time pressurizer model

    International Nuclear Information System (INIS)

    Fakory, M.R.; Seifaee, F.

    1987-01-01

    Recent accidents at nuclear power plants in the US and abroad have prompted accurate analysis and simulation of the plant systems and the training of reactor operators on plant-specific simulators that are equipped with the simulation models. Consequently, several models for real-time and off-time simulation of nuclear reactor systems, with various levels of accuracy and simulation fidelity, have been introduced. Experience with power plant simulation demonstrates that in order to realistically predict and simulate reactor responses during unanticipated transients, it is necessary to equip the simulation model with a multielement pressurizer model. The objective of this paper is to present the results of a five-region drift-flux-based pressurizer model, which has been developed for integration with real-time training simulators. A comparison between the plant data and the results of the nonequilibrium pressurizer model demonstrates that the model is well capable of close simulation of dynamic behavior of the pressurizer system

  14. Digitally Controlled Point of Load Converter with Very Fast Transient Response

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes; Andersen, Michael Andreas E.

    2007-01-01

    voltage mode control and very fast transient response. The DiSOM modulator is combined with a digital PID compensator algorithm is implemented in a hybrid CPLD/FPGA and is used to control a synchronous Buck converter, which is used in typical Point of Load applications. The computational time is only......This paper presents a new Digital Self-Oscillating Modulator (DiSOM) that allows the duty cycle to be changed instantly. The DiSOM modulator is shown to have variable switching that is a function of the duty cycle. Compared to a more traditional digital PWM modulator based on a counter...... and comparator the DiSOM modulator allows the sampling frequency of the output voltage control loop to be higher than the switching frequency of the power converter, typically a DC/DC converter. The features of the DiSOM modulator makes it possible to design a digitally controlled DC/DC converter with linear...

  15. Tiger salamanders' (Ambystoma tigrinum) response learning and usage of visual cues.

    Science.gov (United States)

    Kundey, Shannon M A; Millar, Roberto; McPherson, Justin; Gonzalez, Maya; Fitz, Aleyna; Allen, Chadbourne

    2016-05-01

    We explored tiger salamanders' (Ambystoma tigrinum) learning to execute a response within a maze as proximal visual cue conditions varied. In Experiment 1, salamanders learned to turn consistently in a T-maze for reinforcement before the maze was rotated. All learned the initial task and executed the trained turn during test, suggesting that they learned to demonstrate the reinforced response during training and continued to perform it during test. In a second experiment utilizing a similar procedure, two visual cues were placed consistently at the maze junction. Salamanders were reinforced for turning towards one cue. Cue placement was reversed during test. All learned the initial task, but executed the trained turn rather than turning towards the visual cue during test, evidencing response learning. In Experiment 3, we investigated whether a compound visual cue could control salamanders' behaviour when it was the only cue predictive of reinforcement in a cross-maze by varying start position and cue placement. All learned to turn in the direction indicated by the compound visual cue, indicating that visual cues can come to control their behaviour. Following training, testing revealed that salamanders attended to stimuli foreground over background features. Overall, these results suggest that salamanders learn to execute responses over learning to use visual cues but can use visual cues if required. Our success with this paradigm offers the potential in future studies to explore salamanders' cognition further, as well as to shed light on how features of the tiger salamanders' life history (e.g. hibernation and metamorphosis) impact cognition.

  16. Analysis of the FFTF primary pipe rupture transients

    International Nuclear Information System (INIS)

    Perkins, K.R.; Bari, R.A.; Chen, L.C.; Albright, D.C.

    1979-01-01

    The response of the Fast Flux Test Facility (FFTF) to hypothetical ruptures of the high pressure primary piping has been analyzed using two LMFBR plant systems codes, namely IANUS and DEMO. Comparisons of the average channel temperatures predicted by the two codes show good agreement for identical transients. However, the hot channel temperatures predicted by DEMO are about 60K higher than the corresponding IANUS predictions for severe transients. This difference is attributed to the dynamic hot channel factors employed in DEMO which discount the thermal inertia of the duct walls for rapid transients. DEMO also predicts more severe transients for hot-leg ruptures in FFTF than previously reported analyses for the CRBR

  17. An Artificial Intelligence Approach to Transient Stability Assessment

    OpenAIRE

    Akella, Vijay Ahaskar; Khincha, HP; Kumar, Sreerama R

    1991-01-01

    An artificial intelligence approach to online transient stability assessment is briefly discussed, and some crucial requirements for this algorithm are identified. Solutions to these are proposed. Some new attributes are suggested so as to reflect machine dynamics and changes in the network. Also a new representative learning set algorithm has been developed.

  18. Transients of Water Distribution and Transport in PEFCs

    KAUST Repository

    Hussaini, Irfan

    2008-01-01

    Response of PEM fuel cells to a step-change in load is investigated experimentally in this work. Voltage undershoot, a characteristic feature of such transient response, is shown to be due to transients of water distribution in membrane phase occurring at sub-second time scales. Use of humidified reactants as a means to control magnitude of voltage undershoot has been demonstrated. Constant stoichiometry operation under certain current-step conditions is found to result in reactant starvation, potentially leading to cell shut down. Further, response under step decrease in current density has been explored to determine existence of hysteresis. Under sufficiently humidified conditions, response under forward and reverse step changes are found to be symmetric, but under low RH conditions, voltage undershoot is found to be twice as large as the overshoot. © The Electrochemical Society.

  19. Transient reflectivity on vertically aligned single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Galimberti, Gianluca; Ponzoni, Stefano; Ferrini, Gabriele [Interdisciplinary Laboratory for Advanced Materials Physics (i-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, I-25121 Brescia (Italy); Hofmann, Stephan [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Arshad, Muhammad [Zernike Institute for Advanced Materials, University of Groningen (Netherlands); ICTP, Strada Costiera 11, I-34151 Trieste (Italy); National Centre for Physics Quaid-i-Azam University Islamabad (Pakistan); Cepek, Cinzia [Istituto Officina dei Materiali — CNR, Laboratorio TASC, Area Science Park, Basovizza, I-34149 Trieste (Italy); Pagliara, Stefania, E-mail: pagliara@dmf.unicatt.it [Interdisciplinary Laboratory for Advanced Materials Physics (i-LAMP) and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, I-25121 Brescia (Italy)

    2013-09-30

    One-color transient reflectivity measurements are carried out on two different samples of vertically aligned single-wall carbon nanotube bundles and compared with the response recently published on unaligned bundles. The negative sign of the optical response for both samples indicates that the free electron character revealed on unaligned bundles is only due to the intertube interactions favored by the tube bending. Neither the presence of bundles nor the existence of structural defects in aligned bundles is able to induce a free-electron like behavior of the photoexcited carriers. This result is also confirmed by the presence of non-linear excitonic effects in the transient response of the aligned bundles. - Highlights: • Transient reflectivity measurements on two aligned carbon nanotube samples • Relationship between unalignment and/or bundling and intertube interaction • The bundling is not able to modify the intertube interactions • The presence of structural defects does not affect the intertube interactions • A localized exciton-like behavior has been revealed in these samples.

  20. Learning to inhibit the response during instrumental (operant) extinction.

    Science.gov (United States)

    Bouton, Mark E; Trask, Sydney; Carranza-Jasso, Rodrigo

    2016-07-01

    Five experiments tested implications of the idea that instrumental (operant) extinction involves learning to inhibit the learned response. All experiments used a discriminated operant procedure in which rats were reinforced for lever pressing or chain pulling in the presence of a discriminative stimulus (S), but not in its absence. In Experiment 1, extinction of the response (R) in the presence of S weakened responding in S, but equivalent nonreinforced exposure to S (without the opportunity to make R) did not. Experiment 2 replicated that result and found that extinction of R had no effect on a different R that had also been reinforced in the stimulus. In Experiments 3 and 4, rats first learned to perform several different stimulus and response combinations (S1R1, S2R1, S3R2, and S4R2). Extinction of a response in one stimulus (i.e., S1R1) transferred and weakened the same response, but not a different response, when it was tested in another stimulus (i.e., S2R1 but not S3R2). In Experiment 5, extinction still transferred between S1 and S2 when the stimuli set the occasion for R's association with different types of food pellets. The results confirm the importance of response inhibition in instrumental extinction: Nonreinforcement of the response in S causes the most effective suppression of responding, and response suppression is specific to the response but transfers and influences performance of the same response when it is occasioned by other stimuli. Theoretical and practical implications are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  1. Learning to inhibit the response during instrumental (operant) extinction

    Science.gov (United States)

    Bouton, Mark E.; Trask, Sydney; Carranza-Jasso, Rodrigo

    2016-01-01

    Five experiments tested implications of the idea that instrumental (operant) extinction involves learning to inhibit the learned response. All experiments used a discriminated operant procedure in which rats were reinforced for lever pressing or chain pulling in the presence of a discriminative stimulus (S), but not in its absence. In Experiment 1, extinction of the response (R) in the presence of S weakened responding in S, but equivalent nonreinforced exposure to S (without the opportunity to make R) did not. Experiment 2 replicated that result and found that extinction of R had no effect on a different R that had also been reinforced in the stimulus. In Experiments 3 and 4, rats first learned to perform several different stimulus and response combinations (S1R1, S2R1, S3R2, and S4R2). Extinction of a response in one stimulus (i.e., S1R1) transferred and weakened the same response, but not a different response, when it was tested in another stimulus (i.e., S2R1 but not S3R2). In Experiment 5, extinction still transferred between S1 and S2 when the stimuli set the occasion for R's association with different types of food pellets. The results confirm the importance of response inhibition in instrumental extinction: Nonreinforcement of the response in S causes the most effective suppression of responding, and response suppression is specific to the response but transfers and influences performance of the same response when it is occasioned by other stimuli. Theoretical and practical implications are discussed. PMID:27379715

  2. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Part I: Theory and description of model capabilities

    Science.gov (United States)

    Raffray, A. René; Federici, Gianfranco

    1997-04-01

    RACLETTE (Rate Analysis Code for pLasma Energy Transfer Transient Evaluation), a comprehensive but relatively simple and versatile model, was developed to help in the design analysis of plasma facing components (PFCs) under 'slow' high power transients, such as those associated with plasma vertical displacement events. The model includes all the key surface heat transfer processes such as evaporation, melting, and radiation, and their interaction with the PFC block thermal response and the coolant behaviour. This paper represents part I of two sister and complementary papers. It covers the model description, calibration and validation, and presents a number of parametric analyses shedding light on and identifying trends in the PFC armour block response to high plasma energy deposition transients. Parameters investigated include the plasma energy density and deposition time, the armour thickness and the presence of vapour shielding effects. Part II of the paper focuses on specific design analyses of ITER plasma facing components (divertor, limiter, primary first wall and baffle), including improvements in the thermal-hydraulic modeling required for better understanding the consequences of high energy deposition transients in particular for the ITER limiter case.

  3. RACLETTE: a model for evaluating the thermal response of plasma facing components to slow high power plasma transients. Pt. I. Theory and description of model capabilities

    International Nuclear Information System (INIS)

    Raffray, A.R.; Federici, G.

    1997-01-01

    For pt.II see ibid., p.101-30, 1997. RACLETTE (Rate Analysis Code for pLasma Energy Transfer Transient Evaluation), a comprehensive but relatively simple and versatile model, was developed to help in the design analysis of plasma facing components (PFCs) under 'slow' high power transients, such as those associated with plasma vertical displacement events. The model includes all the key surface heat transfer processes such as evaporation, melting, and radiation, and their interaction with the PFC block thermal response and the coolant behaviour. This paper represents part I of two sister and complementary papers. It covers the model description, calibration and validation, and presents a number of parametric analyses shedding light on and identifying trends in the PFC armour block response to high plasma energy deposition transients. Parameters investigated include the plasma energy density and deposition time, the armour thickness and the presence of vapour shielding effects. Part II of the paper focuses on specific design analyses of ITER plasma facing components (divertor, limiter, primary first wall and baffle), including improvements in the thermal-hydraulic modeling required for better understanding the consequences of high energy deposition transients in particular for the ITER limiter case. (orig.)

  4. Application of the Matrix Pencil Method for Estimating the SEM (Singularity Expansion Method) Poles of Source Free Transient Responses From Multiple Look Directions

    National Research Council Canada - National Science Library

    Sarkar, Tapan

    2000-01-01

    .... The SEM poles are independent of the angle at which the transient response is recorded. The only difference between the various waveforms are that the residues at the various poles are of different magnitudes...

  5. Transient thermal performance analysis of micro heat pipes

    International Nuclear Information System (INIS)

    Liu, Xiangdong; Chen, Yongping

    2013-01-01

    A theoretical analysis of transient fluid flow and heat transfer in a triangular micro heat pipes (MHP) has been conducted to study the thermal response characteristics. By introducing the system identification theory, the quantitative evaluation of the MHP's transient thermal performance is realized. The results indicate that the evaporation and condensation processes are both extended into the adiabatic section. During the start-up process, the capillary radius along axial direction of MHP decreases drastically while the liquid velocity increases quickly at the early transient stage and an approximately linear decrease in wall temperature arises along the axial direction. The MHP behaves as a first-order LTI control system with the constant input power as the 'step input' and the evaporator wall temperature as the 'output'. Two corresponding evaluation criteria derived from the control theory, time constant and temperature constant, are able to quantitatively evaluate the thermal response speed and temperature level of MHP under start-up, which show that a larger triangular groove's hydraulic diameter within 0.18–0.42 mm is able to accelerate the start-up and decrease the start-up temperature level of MHP. Additionally, the MHP starts up fastest using the fluid of ethanol and most slowly using the working fluid of methanol, and the start-up temperature reaches maximum level for acetone and minimum level for the methanol. -- Highlights: • Transient thermal response of micro heat pipe is simulated by an improved model. • Control theory is introduced to quantify the thermal response of micro heat pipe. • Evaluation criteria are proposed to represent thermal response of micro heat pipe. • Effects of groove dimensions and working fluids on start-up of micro heat pipe are evaluated

  6. Reappraising social insect behavior through aversive responsiveness and learning.

    Science.gov (United States)

    Roussel, Edith; Carcaud, Julie; Sandoz, Jean-Christophe; Giurfa, Martin

    2009-01-01

    The success of social insects can be in part attributed to their division of labor, which has been explained by a response threshold model. This model posits that individuals differ in their response thresholds to task-associated stimuli, so that individuals with lower thresholds specialize in this task. This model is at odds with findings on honeybee behavior as nectar and pollen foragers exhibit different responsiveness to sucrose, with nectar foragers having higher response thresholds to sucrose concentration. Moreover, it has been suggested that sucrose responsiveness correlates with responsiveness to most if not all other stimuli. If this is the case, explaining task specialization and the origins of division of labor on the basis of differences in response thresholds is difficult. To compare responsiveness to stimuli presenting clear-cut differences in hedonic value and behavioral contexts, we measured appetitive and aversive responsiveness in the same bees in the laboratory. We quantified proboscis extension responses to increasing sucrose concentrations and sting extension responses to electric shocks of increasing voltage. We analyzed the relationship between aversive responsiveness and aversive olfactory conditioning of the sting extension reflex, and determined how this relationship relates to division of labor. Sucrose and shock responsiveness measured in the same bees did not correlate, thus suggesting that they correspond to independent behavioral syndromes, a foraging and a defensive one. Bees which were more responsive to shock learned and memorized better aversive associations. Finally, guards were less responsive than nectar foragers to electric shocks, exhibiting higher tolerance to low voltage shocks. Consequently, foragers, which are more sensitive, were the ones learning and memorizing better in aversive conditioning. Our results constitute the first integrative study on how aversive responsiveness affects learning, memory and social

  7. Reappraising social insect behavior through aversive responsiveness and learning.

    Directory of Open Access Journals (Sweden)

    Edith Roussel

    Full Text Available The success of social insects can be in part attributed to their division of labor, which has been explained by a response threshold model. This model posits that individuals differ in their response thresholds to task-associated stimuli, so that individuals with lower thresholds specialize in this task. This model is at odds with findings on honeybee behavior as nectar and pollen foragers exhibit different responsiveness to sucrose, with nectar foragers having higher response thresholds to sucrose concentration. Moreover, it has been suggested that sucrose responsiveness correlates with responsiveness to most if not all other stimuli. If this is the case, explaining task specialization and the origins of division of labor on the basis of differences in response thresholds is difficult.To compare responsiveness to stimuli presenting clear-cut differences in hedonic value and behavioral contexts, we measured appetitive and aversive responsiveness in the same bees in the laboratory. We quantified proboscis extension responses to increasing sucrose concentrations and sting extension responses to electric shocks of increasing voltage. We analyzed the relationship between aversive responsiveness and aversive olfactory conditioning of the sting extension reflex, and determined how this relationship relates to division of labor.Sucrose and shock responsiveness measured in the same bees did not correlate, thus suggesting that they correspond to independent behavioral syndromes, a foraging and a defensive one. Bees which were more responsive to shock learned and memorized better aversive associations. Finally, guards were less responsive than nectar foragers to electric shocks, exhibiting higher tolerance to low voltage shocks. Consequently, foragers, which are more sensitive, were the ones learning and memorizing better in aversive conditioning.Our results constitute the first integrative study on how aversive responsiveness affects learning, memory and

  8. Cooperative Learning, Responsibility, Ambiguity, Controversy and Support in Motivating Students

    Directory of Open Access Journals (Sweden)

    Ronald Brecke, PhD

    2007-08-01

    Full Text Available This paper argues that student motivation is nurtured more by intrinsic rather than extrinsic rewards. Rather than relying on grades alone to stimulate students, this paper explores how engendering a natural critical learning environment can give students a sense of ownership in their own learning and lead to their commitment to that learning. We examine uses of cooperative learning, shared responsibility, ambiguity, controversy and support in student motivation.

  9. Cooperative Learning, Responsibility, Ambiguity, Controversy and Support in Motivating Students

    Directory of Open Access Journals (Sweden)

    Ronald Brecke

    2007-01-01

    Full Text Available This paper argues that student motivation is nurtured more by intrinsic rather than extrinsic rewards. Rather than relying on grades alone to stimulate students, this paper explores how engendering a natural critical learning environment can give students a sense of ownership in their own learning and lead to their commitment to that learning. We examine uses of cooperative learning, shared responsibility, ambiguity, controversy and support in student motivation.

  10. Transient response of a liquid injector to a steep-fronted transverse pressure wave

    Science.gov (United States)

    Lim, D.; Heister, S.; Stechmann, D.; Kan, B.

    2017-12-01

    Motivated by the dynamic injection environment posed by unsteady pressure gain combustion processes, an experimental apparatus was developed to visualize the dynamic response of a transparent liquid injector subjected to a single steep-fronted transverse pressure wave. Experiments were conducted at atmospheric pressure with a variety of acrylic injector passage designs using water as the working fluid. High-speed visual observations were made of the injector exit near field, and the extent of backflow and the time to refill the orifice passage were characterized over a range of injection pressures. A companion transient one-dimensional model was developed for interpretation of the results and to elucidate the trends with regard to the strength of the transverse pressure wave. Results from the model were compared with the experimental observations.

  11. Service Learning and the Development of Social Responsibility.

    Science.gov (United States)

    Johnson, Scott D.; Bozeman, Marci

    This essay presents the findings of a study employing a developmental approach to student acquisition of social responsibility. Professors at seven collegiate institutions of differing types who teach service-learning courses were asked if they would be willing to include their students in a study of social responsibility development through…

  12. Stochastic resonance of ensemble neurons for transient spike trains: Wavelet analysis

    International Nuclear Information System (INIS)

    Hasegawa, Hideo

    2002-01-01

    By using the wavelet transformation (WT), I have analyzed the response of an ensemble of N (=1, 10, 100, and 500) Hodgkin-Huxley neurons to transient M-pulse spike trains (M=1 to 3) with independent Gaussian noises. The cross correlation between the input and output signals is expressed in terms of the WT expansion coefficients. The signal-to-noise ratio (SNR) is evaluated by using the denoising method within the WT, by which the noise contribution is extracted from the output signals. Although the response of a single (N=1) neuron to subthreshold transient signals with noises is quite unreliable, the transmission fidelity assessed by the cross correlation and SNR is shown to be much improved by increasing the value of N: a population of neurons plays an indispensable role in the stochastic resonance (SR) for transient spike inputs. It is also shown that in a large-scale ensemble, the transmission fidelity for suprathreshold transient spikes is not significantly degraded by a weak noise which is responsible to SR for subthreshold inputs

  13. Learning Responsibility and Balance of Power

    Science.gov (United States)

    Çam, Sefika Sümeyye; Ünal Oruç, Eylem

    2014-01-01

    This qualitative study aims to determine teacher perspectives on learning responsibility and balance of power. The research design is case study which was conducted on four primary school teachers. The data were collected with semi-structured interviews and the data obtained were analyzed with categorical analysis, a type of content analysis. The…

  14. Response of hyporheic zones to transient forcing

    Science.gov (United States)

    Singh, T.; Wu, L.; Gomez-Velez, J. D.; Krause, S.; Hannah, D. M.; Lewandowski, J.; Nuetzmann, G.

    2017-12-01

    Exchange of water, solutes, and energy between river channels and hyporheic zones (HZs) modulates biogeochemical cycling, regulates stream temperature and impacts ecological structure and function. Numerical modelling of HZ processes is required as field observations are challenging for transient flow. To gain a deeper mechanistic understanding of the effects of transient discharge on hyporheic exchange, we performed a systematic analysis using numerical experiments. In this case, we vary (i) the characteristics of time-varying flood events; (ii) river bedform geometry; (iii) river hydraulic geometry; and (iv) the magnitude and direction of groundwater fluxes (neutral, gaining and losing conditions). We conceptualize the stream bed as a two-dimensional system. Whereby the flow is driven by a dynamically changing head distribution at the water-sediment interface and is modulated by steady groundwater flow. Our model estimates both net values for a single bedform and spatial distributions of (i) the flow field; (ii) mean residence times; and (iii) the concentration of a conservative tracer. A detailed sensitivity analysis was performed by changing channel slope, flood characteristics, groundwater upwelling/downwelling fluxes and biogeochemical time-scales in different bedforms such as ripples, dunes and alternating bars. Results show that change of parameters can have a substantial impact on exchange fluxes which can lead to the expansion, contraction, emergence and/or dissipation of HZs . Our results also reveal that groundwater fluxes have different impacts on HZs during flood events, depending on the channel slope and bedform topography. It is found that topographies with smaller aspect ratios and shallower slopes are more affected by groundwater upwelling/downwelling fluxes during flood events. The analysis of biogeochemical transformations shows that discharge events can potentially affects the efficiencies of nitrate removal. Taking into consideration multiple

  15. Implicit Learning Abilities Predict Treatment Response in Autism Spectrum Disorders

    Science.gov (United States)

    2015-09-01

    early behavioral interventions are the most effective treatment for Autism Spectrum Disorder (ASD), but almost half of the children do not make...behavioral intervention . 2. KEYWORDS Autism Spectrum Disorder , implicit learning, associative learning, individual differences, functional Magnetic...2 AWARD NUMBER: W81XWH-14-1-0261 TITLE: Implicit Learning Abilities Predict Treatment Response in Autism Spectrum Disorders PRINCIPAL

  16. Response of GaAs charge storage devices to transient ionizing radiation

    Science.gov (United States)

    Hetherington, D. L.; Klem, J. F.; Hughes, R. C.; Weaver, H. T.

    Charge storage devices in which non-equilibrium depletion regions represent stored charge are sensitive to ionizing radiation. This results since the radiation generates electron-hole pairs that neutralize excess ionized dopant charge. Silicon structures, such as dynamic RAM or CCD cells are particularly sensitive to radiation since carrier diffusion lengths in this material are often much longer than the depletion width, allowing collection of significant quantities of charge from quasi-neutral sections of the device. For GaAs the situation is somewhat different in that minority carrier diffusion lengths are shorter than in silicon, and although mobilities are higher, we expect a reduction of radiation sensitivity as suggested by observations of reduced quantum efficiency in GaAs solar cells. Dynamic memory cells in GaAs have potential increased retention times. In this paper, we report the response of a novel GaAs dynamic memory element to transient ionizing radiation. The charge readout technique is nondestructive over a reasonable applied voltage range and is more sensitive to stored charge than a simple capacitor.

  17. Planning the bioterrorism response supply chain: learn and live.

    Science.gov (United States)

    Brandeau, Margaret L; Hutton, David W; Owens, Douglas K; Bravata, Dena M

    2007-01-01

    Responses to bioterrorism require rapid procurement and distribution of medical and pharmaceutical supplies, trained personnel, and information. Thus, they present significant logistical challenges. On the basis of a review of the manufacturing and service supply chain literature, the authors identified five supply chain strategies that can potentially increase the speed of response to a bioterrorism attack, reduce inventories, and save money: effective supply chain network design; effective inventory management; postponement of product customization and modularization of component parts; coordination of supply chain stakeholders and appropriate use of incentives; and effective information management. The authors describe how concepts learned from published evaluations of manufacturing and service supply chains, as well as lessons learned from responses to natural disasters, naturally occurring outbreaks, and the 2001 US anthrax attacks, can be applied to design, evaluate, and improve the bioterrorism response supply chain. Such lessons could also be applied to the response supply chains for disease outbreaks and natural and manmade disasters.

  18. INTRANS. A computer code for the non-linear structural response analysis of reactor internals under transient loads

    International Nuclear Information System (INIS)

    Ramani, D.T.

    1977-01-01

    The 'INTRANS' system is a general purpose computer code, designed to perform linear and non-linear structural stress and deflection analysis of impacting or non-impacting nuclear reactor internals components coupled with reactor vessel, shield building and external as well as internal gapped spring support system. This paper describes in general a unique computational procedure for evaluating the dynamic response of reactor internals, descretised as beam and lumped mass structural system and subjected to external transient loads such as seismic and LOCA time-history forces. The computational procedure is outlined in the INTRANS code, which computes component flexibilities of a discrete lumped mass planar model of reactor internals by idealising an assemblage of finite elements consisting of linear elastic beams with bending, torsional and shear stiffnesses interacted with external or internal linear as well as non-linear multi-gapped spring support system. The method of analysis is based on the displacement method and the code uses the fourth-order Runge-Kutta numerical integration technique as a basis for solution of dynamic equilibrium equations of motion for the system. During the computing process, the dynamic response of each lumped mass is calculated at specific instant of time using well-known step-by-step procedure. At any instant of time then, the transient dynamic motions of the system are held stationary and based on the predicted motions and internal forces of the previous instant. From which complete response at any time-step of interest may then be computed. Using this iterative process, the relationship between motions and internal forces is satisfied step by step throughout the time interval

  19. A fast transient response low dropout regulator with current control methodology

    Energy Technology Data Exchange (ETDEWEB)

    Ma Zhuo; Guo Yang; Duan Zhikui; Xie Lunguo; Chen Jihua; Yu Jinshan, E-mail: guoyang@nudt.edu.cn [School of Computer, National University of Defense Technology, Changsha 410073 (China)

    2011-08-15

    A transient performance optimized CCL-LDO regulator is proposed. In the CCL-LDO, the control method of the charge pump phase-locked loop is adopted. A current control loop has the feedback signal and reference current to be compared, and then a loop filter generates the gate voltage of the power MOSFET by integrating the error current. The CCL-LDO has the optimized damping coefficient and natural resonant frequency, while its output voltage can be sub-1-V and is not restricted by the reference voltage. With a 1 {mu}F decoupling capacitor, the experimental results based on a 0.13 {mu}m CMOS process show that the output voltage is 1.0 V; when the workload changes from 100 {mu}A to 100 mA transiently, the stable dropout is 4.25 mV, the settling time is 8.2 {mu}s and the undershoot is 5.11 mV; when the workload changes from 100 mA to 100 {mu}A transiently, the stable dropout is 4.25 mV, the settling time is 23.3 {mu}s and the overshoot is 6.21 mV. The PSRR value is more than -95 dB. Most of the attributes of the CCL-LDO are improved rapidly with a FOM value of 0.0097.

  20. A fast transient response low dropout regulator with current control methodology

    International Nuclear Information System (INIS)

    Ma Zhuo; Guo Yang; Duan Zhikui; Xie Lunguo; Chen Jihua; Yu Jinshan

    2011-01-01

    A transient performance optimized CCL-LDO regulator is proposed. In the CCL-LDO, the control method of the charge pump phase-locked loop is adopted. A current control loop has the feedback signal and reference current to be compared, and then a loop filter generates the gate voltage of the power MOSFET by integrating the error current. The CCL-LDO has the optimized damping coefficient and natural resonant frequency, while its output voltage can be sub-1-V and is not restricted by the reference voltage. With a 1 μF decoupling capacitor, the experimental results based on a 0.13 μm CMOS process show that the output voltage is 1.0 V; when the workload changes from 100 μA to 100 mA transiently, the stable dropout is 4.25 mV, the settling time is 8.2 μs and the undershoot is 5.11 mV; when the workload changes from 100 mA to 100 μA transiently, the stable dropout is 4.25 mV, the settling time is 23.3 μs and the overshoot is 6.21 mV. The PSRR value is more than -95 dB. Most of the attributes of the CCL-LDO are improved rapidly with a FOM value of 0.0097.

  1. The influence of internal current loop on transient response performance of I-V droop controlled paralleled DC-DC converters

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Guerrero, Josep M.

    2017-01-01

    The external droop control loop of I-V droop control is designed as a voltage loop with embedded virtual impedance, so the internal current loop plays a major role in the system bandwidth. Thus, in this paper, the influence of internal current loop on transient response performance of I-V droop...... controlled paralleled dc-dc converters is analyzed, which is guided and significant for its industry application. The model which is used for dynamic analysis is built, and the root locus method is used based on the model to analyze the dynamic response of the system by shifting different control parameters...

  2. Transient and Steady-State Responses of an Asymmetric Nonlinear Oscillator

    Directory of Open Access Journals (Sweden)

    Alex Elías-Zúñiga

    2013-01-01

    oscillator that describes the motion of a damped, forced system supported symmetrically by simple shear springs on a smooth inclined bearing surface. We also use the percentage overshoot value to study the influence of damping and nonlinearity on the transient and steady-state oscillatory amplitudes.

  3. Evaluation of time integration methods for transient response analysis of nonlinear structures

    International Nuclear Information System (INIS)

    Park, K.C.

    1975-01-01

    Recent developments in the evaluation of direct time integration methods for the transient response analysis of nonlinear structures are presented. These developments, which are based on local stability considerations of an integrator, show that the interaction between temporal step size and nonlinearities of structural systems has a pronounced effect on both accuracy and stability of a given time integration method. The resulting evaluation technique is applied to a model nonlinear problem, in order to: 1) demonstrate that it eliminates the present costly process of evaluating time integrator for nonlinear structural systems via extensive numerical experiments; 2) identify the desirable characteristics of time integration methods for nonlinear structural problems; 3) develop improved stiffly-stable methods for application to nonlinear structures. Extension of the methodology for examination of the interaction between a time integrator and the approximate treatment of nonlinearities (such as due to pseudo-force or incremental solution procedures) is also discussed. (Auth.)

  4. Transient Dynamic Response of Delaminated Composite Rotating Shallow Shells Subjected to Impact

    Directory of Open Access Journals (Sweden)

    Amit Karmakar

    2006-01-01

    Full Text Available In this paper a transient dynamic finite element analysis is presented to study the response of delaminated composite pretwisted rotating shallow shells subjected to low velocity normal impact. Lagrange's equation of motion is used to derive the dynamic equilibrium equation and moderate rotational speeds are considered wherein the Coriolis effect is negligible. An eight noded isoparametric plate bending element is employed in the finite element formulation incorporating rotary inertia and effects of transverse shear deformation based on Mindlin's theory. To satisfy the compatibility of deformation and equilibrium of resultant forces and moments at the delamination crack front a multipoint constraint algorithm is incorporated which leads to unsymmetric stiffness matrices. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the contact force, and the time dependent equations are solved by Newmark's time integration algorithm. Parametric studies are performed in respect of location of delamination, angle of twist and rotational speed for centrally impacted graphite-epoxy composite cylindrical shells.

  5. Western Wind and Solar Integration Study Phase 3 – Frequency Response and Transient Stability

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N. W. [GE Energy Management, Schenectady, NY (United States); Shao, M. [GE Energy Management, Schenectady, NY (United States); Pajic, S. [GE Energy Management, Schenectady, NY (United States); D' Aquila, R. [GE Energy Management, Schenectady, NY (United States)

    2014-12-01

    Power system operators and utilities worldwide have concerns about the impact of high-penetration wind and solar generation on electric grid reliability (EirGrid 2011b, Hydro-Quebec 2006, ERCOT 2010). The stability of North American grids under these conditions is a particular concern and possible impediment to reaching future renewable energy goals. Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3) considers a 33% wind and solar annual energy penetration level that results in substantial changes to the characteristics of the bulk power system, including different power flow patterns, different commitment and dispatch of existing synchronous generation, and different dynamic behavior of wind and solar generation. WWSIS-3 evaluates two specific aspects of fundamental frequency system stability: frequency response and transient stability.

  6. Whole-body irradiation transiently diminishes the adrenocorticotropin response to recombinant human interleukin-1{alpha}

    Energy Technology Data Exchange (ETDEWEB)

    Perlstein, R.S.; Mehta, N.R.; Neta, R.; Whitnall, M.H. [Armed Forces Radiobiology Research Institute, Bethesda, MD (United States); Mougey, E.H. [Walter Reed Army Institute of Research, Washington, DC (United States)

    1995-03-01

    Recombinant human interleukin-1{alpha} (rhIL-1{alpha}) has significant potential as a radioprotector and/or treatment for radiation-induced hematopoietic injury. Both IL-1 and whole-body ionizing irradiation acutely stimulate the hypothalamic-pituitary-adrenal axis. We therefore assessed the interaction of whole-body irradiation and rhIL-1{alpha} in altering the functioning of the axis in mice. Specifically, we determined the adrenocorticotropin (ACTH) and corticosterone responses to rhIL-1{alpha} administered just before and hours to days after whole-body or sham irradiation. Our results indicate that whole-body irradiation does not potentiate the rhIL-1{alpha}-induced increase in ACTH levels at the doses used. In fact, the rhIL-1{alpha}-induced increase in plasma ACTH is transiently impaired when the cytokine is administered 5 h after, but not 1 h before, exposure to whole-body irradiation. The ACTH response may be inhibited by elevated corticosterone levels after whole-body irradiation, or by other radiation-induced effects on the pituitary gland and hypothalamus. 36 refs., 3 figs.

  7. Sucrose Responsiveness, Learning Success, and Task Specialization in Ants

    Science.gov (United States)

    Perez, Margot; Rolland, Uther; Giurfa,, Martin; d'Ettorre, Patrizia

    2013-01-01

    Social insects possess remarkable learning capabilities, which are crucial for their ecological success. They also exhibit interindividual differences in responsiveness to environmental stimuli, which underlie task specialization and division of labor. Here we investigated for the first time the relationships between sucrose responsiveness,…

  8. Experimental study for transient response of a double-tube thermosyphon (DTTH)

    International Nuclear Information System (INIS)

    Salem, M.A.M.

    2010-01-01

    study includes the analysis of:1-Boiling and non-boiling heat transfer coefficients of the eva porator.2-Temperature profile along the double-tube thermosyphon.In addition to the performance study for comparison purposes mainly involves:1-Transient response of the double-tube thermosyphon.2-Average evaporator heat transfer coefficient.3-Equivalent overall heat transfer coefficient.4-Effective thermal conductivity of thermosyphon.

  9. Dissociation of rapid response learning and facilitation in perceptual and conceptual networks of person recognition.

    Science.gov (United States)

    Valt, Christian; Klein, Christoph; Boehm, Stephan G

    2015-08-01

    Repetition priming is a prominent example of non-declarative memory, and it increases the accuracy and speed of responses to repeatedly processed stimuli. Major long-hold memory theories posit that repetition priming results from facilitation within perceptual and conceptual networks for stimulus recognition and categorization. Stimuli can also be bound to particular responses, and it has recently been suggested that this rapid response learning, not network facilitation, provides a sound theory of priming of object recognition. Here, we addressed the relevance of network facilitation and rapid response learning for priming of person recognition with a view to advance general theories of priming. In four experiments, participants performed conceptual decisions like occupation or nationality judgments for famous faces. The magnitude of rapid response learning varied across experiments, and rapid response learning co-occurred and interacted with facilitation in perceptual and conceptual networks. These findings indicate that rapid response learning and facilitation in perceptual and conceptual networks are complementary rather than competing theories of priming. Thus, future memory theories need to incorporate both rapid response learning and network facilitation as individual facets of priming. © 2014 The British Psychological Society.

  10. Transients of Water Distribution and Transport in PEM Fuel Cells

    KAUST Repository

    Hussaini, Irfan S.; Wang, Chao-Yang

    2009-01-01

    The response of polymer electrolyte membrane (PEM) fuel cells to a step change in load is investigated experimentally in this work. Voltage undershoot, a characteristic feature of transient response following a step increase in current, is due to transients of water distribution in the membrane and ionomers occurring at subsecond time scales. The use of humidified reactants as a means to control the magnitude of voltage undershoot is demonstrated. Further, the response under a step decrease in current density is explored to determine the existence of hysteresis. Under sufficiently humidified conditions, the responses under forward and reverse step changes are symmetric, but under low relative humidity conditions, voltage undershoot is twice as large as the overshoot. © 2009 The Electrochemical Society.

  11. Study on Transient Properties of Levitated Object in Near-Field Acoustic Levitation

    International Nuclear Information System (INIS)

    Jia Bing; Chen Chao; Zhao Chunsheng

    2011-01-01

    A new approach to the study on the transient properties of the levitated object in near-field acoustic levitation (NFAL) is presented. In this article, the transient response characteristics, including the levitated height of an object with radius of 24 mm and thickness of 5 mm, the radial velocity and pressure difference of gas at the boundary of clearance between the levitated object and radiating surface (squeeze film), is calculated according to several velocity amplitudes of radiating surface. First, the basic equations in fluid areas on Arbitrary Lagrange-Euler (ALE) form are numerically solved by using streamline upwind petrov galerkin (SUPG) finite elements method. Second, the formed algebraic equations and solid control equations are solved by using synchronous alternating method to gain the transient messages of the levitated object and gas in the squeeze film. Through theoretical and numerical analyses, it is found that there is a oscillation time in the transient process and that the response time does not simply increase with the increasing of velocity amplitudes of radiating surface. More investigations in this paper are helpful for the understanding of the transient properties of levitated object in NFAL, which are in favor of enhancing stabilities and responsiveness of levitated object. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  12. Study on Transient Properties of Levitated Object in Near-Field Acoustic Levitation

    Science.gov (United States)

    Jia, Bing; Chen, Chao; Zhao, Chun-Sheng

    2011-12-01

    A new approach to the study on the transient properties of the levitated object in near-field acoustic levitation (NFAL) is presented. In this article, the transient response characteristics, including the levitated height of an object with radius of 24 mm and thickness of 5 mm, the radial velocity and pressure difference of gas at the boundary of clearance between the levitated object and radiating surface (squeeze film), is calculated according to several velocity amplitudes of radiating surface. First, the basic equations in fluid areas on Arbitrary Lagrange—Euler (ALE) form are numerically solved by using streamline upwind petrov galerkin (SUPG) finite elements method. Second, the formed algebraic equations and solid control equations are solved by using synchronous alternating method to gain the transient messages of the levitated object and gas in the squeeze film. Through theoretical and numerical analyses, it is found that there is a oscillation time in the transient process and that the response time does not simply increase with the increasing of velocity amplitudes of radiating surface. More investigations in this paper are helpful for the understanding of the transient properties of levitated object in NFAL, which are in favor of enhancing stabilities and responsiveness of levitated object.

  13. Transient behaviour of small HTR for cogeneration

    International Nuclear Information System (INIS)

    Verkerk, E.C.; Van Heek, A.I.

    2000-01-01

    The Dutch market for combined generation of heat and power identifies a unit size of 40 MW thermal for the conceptual design of a nuclear cogeneration plant. The ACACIA system provides 14 MWe electricity combined with 17 t/h of high temperature steam (220 deg C, 10 bar) with a pebble-bed high temperature reactor directly coupled with a helium compressor and a helium turbine. The design of this small CHP unit that is used for industrial applications is mainly based on a pre-feasibility study in 1996, performed by a joint working group of five Dutch organisations, in which technical feasibility was shown. Thermal hydraulic and reactor physics analyses show favourable control characteristics during normal operation and a benign response to loss of helium coolant and loss of flow conditions. Throughout the response on these highly infrequent conditions, ample margin exists between the highest fuel temperatures and the temperature above which fuel degradation will occur. To come to quantitative statements about the ACACIA transient behaviour, a calculational coupling between the high temperature reactor core analysis code package PANTHER/DIREKT and the thermal hydraulic code RELAP5 for the energy conversion system has been made. This coupling offers a more realistic simulation of the entire system, since it removes the necessity of forcing boundary conditions on the simulation models at the data transfer points. In this paper, the models used for the dynamic components of the energy conversion system are described, and the results of the calculation for two operational transients in order to demonstrate the effects of the interaction between reactor core and its energy conversion system are shown. Several transient cases that are representative as operational transients for an HTR will be discussed, including one representing a load rejection case that shows the functioning of the control system, in particular the bypass valve. Another transient is a load following

  14. Theory of strong-field attosecond transient absorption

    International Nuclear Information System (INIS)

    Wu, Mengxi; Chen, Shaohao; Camp, Seth; Schafer, Kenneth J; Gaarde, Mette B

    2016-01-01

    Attosecond transient absorption is one of the promising new techniques being developed to exploit the availability of sub-femtosecond extreme ultraviolet (XUV) pulses to study the dynamics of the electron on its natural time scale. The temporal resolution in a transient absorption setup comes from the control of the relative delay and coherence between pump and probe pulses, while the spectral resolution comes from the characteristic width of the features that are being probed. In this review we focus on transient absorption scenarios where an attosecond pulse of XUV radiation creates a broadband excitation that is subsequently probed by a few cycle infrared (IR) laser. Because the attosecond XUV pulses are locked to the IR field cycle, the exchange of energy in the laser–matter interaction can be studied with unprecedented precision. We focus on the transient absorption by helium atoms of XUV radiation around the first ionization threshold, where we can simultaneoulsy solve the time-dependent Schrödinger equation for the single atom response and the Maxwell wave equation for the collective response of the nonlinear medium. We use a time-domain method that allows us to treat on an equal footing all the different linear and nonlinear processes by which the medium can exchange energy with the fields. We present several simple models, based on a few-level system interacting with a strong IR field, to explain many of the novel features found in attosecond transient absorption spectrograms. These include the presence of light-induced states, which demonstrate the ability to probe the dressed states of the atom. We also present a time-domain interpretation of the resonant pulse propagation features that appear in absorption spectra in dense, macroscopic media. We close by reviewing several recent experimental results that can be explained in terms of the models we discuss. Our aim is to present a road map for understanding future attosecond transient absorption

  15. How does feedback in mini-CEX affect students' learning response?

    Science.gov (United States)

    Sudarso, Sulistiawati; Rahayu, Gandes Retno; Suhoyo, Yoyo

    2016-12-19

    This study was aimed to explore students' learning response toward feedback during mini-CEX encounter. This study used a phenomenological approach to identify the students' experiences toward feedback during mini-CEX encounter. Data was collected using Focus Group Discussion (FGD) for all students who were in their final week of clerkship in the internal medicine rotation. There were 4 FGD groups (6 students for each group). All FGD were audio-taped and transcribed verbatim. The FGD transcripts were analyzed thematically and managed using Atlas-ti (version 7.0). Feedback content and the way of providing feedback on mini-CEX stimulated students' internal process, including self-reflection, emotional response, and motivation. These internal processes encouraged the students to take action or do a follow-up on the feedback to improve their learning process. In addition, there was also an external factor, namely consequences, which also influenced the students' reaction to the follow-up on feedback. In the end, this action caused several learning effects that resulted in the students' increased self-efficacy, attitude, knowledge and clinical skill. Feedback content and the way of providing feedback on mini-CEX stimulates the students' internal processes to do a follow-up on feedback. However, another external factor also affects the students' decision on the follow-up actions. The follow-ups result in various learning effects on the students. Feedback given along with summative assessment enhances learning effects on students, as well. It is suggested that supervisors of clinical education are prepared to comprehend every factor influencing feedback on mini CEX to improve the students' learning response.

  16. Effect of burnup on the response of stainless steel-clad mixed-oxide fuels to simulated thermal transients

    International Nuclear Information System (INIS)

    Fenske, G.R.; Badyopadhyay, G.

    1981-01-01

    Direct electrical heating experiments were performed on irradiated fuel to study the fuel and cladding response as a function of burnup during a slow thermal transient. The results indicated that the nature and extent of the fuel and cladding behavior depended on the quantity of fission gas retained in the fuel. Fission-gas-driven fuel ejection occurred as the molten cladding flowed down the stack exposing bare, radially unrestrained fuel. The fuel dispersion occurred in the absence of molten fuel and the amount of fuel ejected increased with increasing burnup. 31 refs

  17. Transient activation of dopaminergic neurons during development modulates visual responsiveness, locomotion and brain activity in a dopamine ontogeny model of schizophrenia.

    Science.gov (United States)

    Calcagno, B; Eyles, D; van Alphen, B; van Swinderen, B

    2013-01-08

    It has been observed that certain developmental environmental risk factors for schizophrenia when modeled in rodents alter the trajectory of dopaminergic development, leading to persistent behavioural changes in adults. This has recently been articulated as the "dopamine ontogeny hypothesis of schizophrenia". To test one aspect of this hypothesis, namely that transient dopaminergic effects during development modulate attention-like behavior and arousal in adults, we turned to a small-brain model, Drosophila melanogaster. By applying genetic tools allowing transient activation or silencing of dopaminergic neurons in the fly brain, we investigated whether a critical window exists during development when altered dopamine (DA) activity levels could lead to impairments in arousal states in adult animals. We found that increased activity in dopaminergic neurons in later stages of development significantly increased visual responsiveness and locomotion, especially in adult males. This misallocation of visual salience and hyperactivity mimicked the effect of acute methamphetamine feeding to adult flies, suggesting up-regulated DA signaling could result from developmental manipulations. Finally, brain recordings revealed significantly reduced gamma-band activity in adult animals exposed to the transient developmental insult. Together, these data support the idea that transient alterations in DA signaling during development can permanently alter behavior in adults, and that a reductionist model such as Drosophila can be used to investigate potential mechanisms underlying complex cognitive disorders such as schizophrenia.

  18. Deep-HiTS: Rotation Invariant Convolutional Neural Network for Transient Detection

    Science.gov (United States)

    Cabrera-Vives, Guillermo; Reyes, Ignacio; Förster, Francisco; Estévez, Pablo A.; Maureira, Juan-Carlos

    2017-02-01

    We introduce Deep-HiTS, a rotation-invariant convolutional neural network (CNN) model for classifying images of transient candidates into artifacts or real sources for the High cadence Transient Survey (HiTS). CNNs have the advantage of learning the features automatically from the data while achieving high performance. We compare our CNN model against a feature engineering approach using random forests (RFs). We show that our CNN significantly outperforms the RF model, reducing the error by almost half. Furthermore, for a fixed number of approximately 2000 allowed false transient candidates per night, we are able to reduce the misclassified real transients by approximately one-fifth. To the best of our knowledge, this is the first time CNNs have been used to detect astronomical transient events. Our approach will be very useful when processing images from next generation instruments such as the Large Synoptic Survey Telescope. We have made all our code and data available to the community for the sake of allowing further developments and comparisons at https://github.com/guille-c/Deep-HiTS. Deep-HiTS is licensed under the terms of the GNU General Public License v3.0.

  19. Cortical computations via transient attractors.

    Science.gov (United States)

    Rourke, Oliver L C; Butts, Daniel A

    2017-01-01

    The ability of sensory networks to transiently store information on the scale of seconds can confer many advantages in processing time-varying stimuli. How a network could store information on such intermediate time scales, between typical neurophysiological time scales and those of long-term memory, is typically attributed to persistent neural activity. An alternative mechanism which might allow for such information storage is through temporary modifications to the neural connectivity which decay on the same second-long time scale as the underlying memories. Earlier work that has explored this method has done so by emphasizing one attractor from a limited, pre-defined set. Here, we describe an alternative, a Transient Attractor network, which can learn any pattern presented to it, store several simultaneously, and robustly recall them on demand using targeted probes in a manner reminiscent of Hopfield networks. We hypothesize that such functionality could be usefully embedded within sensory cortex, and allow for a flexibly-gated short-term memory, as well as conferring the ability of the network to perform automatic de-noising, and separation of input signals into distinct perceptual objects. We demonstrate that the stored information can be refreshed to extend storage time, is not sensitive to noise in the system, and can be turned on or off by simple neuromodulation. The diverse capabilities of transient attractors, as well as their resemblance to many features observed in sensory cortex, suggest the possibility that their actions might underlie neural processing in many sensory areas.

  20. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    International Nuclear Information System (INIS)

    Sanders, N. E.; Soderberg, A. M.; Betancourt, M.

    2015-01-01

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST

  1. UNSUPERVISED TRANSIENT LIGHT CURVE ANALYSIS VIA HIERARCHICAL BAYESIAN INFERENCE

    Energy Technology Data Exchange (ETDEWEB)

    Sanders, N. E.; Soderberg, A. M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Betancourt, M., E-mail: nsanders@cfa.harvard.edu [Department of Statistics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-02-10

    Historically, light curve studies of supernovae (SNe) and other transient classes have focused on individual objects with copious and high signal-to-noise observations. In the nascent era of wide field transient searches, objects with detailed observations are decreasing as a fraction of the overall known SN population, and this strategy sacrifices the majority of the information contained in the data about the underlying population of transients. A population level modeling approach, simultaneously fitting all available observations of objects in a transient sub-class of interest, fully mines the data to infer the properties of the population and avoids certain systematic biases. We present a novel hierarchical Bayesian statistical model for population level modeling of transient light curves, and discuss its implementation using an efficient Hamiltonian Monte Carlo technique. As a test case, we apply this model to the Type IIP SN sample from the Pan-STARRS1 Medium Deep Survey, consisting of 18,837 photometric observations of 76 SNe, corresponding to a joint posterior distribution with 9176 parameters under our model. Our hierarchical model fits provide improved constraints on light curve parameters relevant to the physical properties of their progenitor stars relative to modeling individual light curves alone. Moreover, we directly evaluate the probability for occurrence rates of unseen light curve characteristics from the model hyperparameters, addressing observational biases in survey methodology. We view this modeling framework as an unsupervised machine learning technique with the ability to maximize scientific returns from data to be collected by future wide field transient searches like LSST.

  2. The Coda of the Transient Response in a Sensitive Cochlea: A Computational Modeling Study.

    Directory of Open Access Journals (Sweden)

    Yizeng Li

    2016-07-01

    Full Text Available In a sensitive cochlea, the basilar membrane response to transient excitation of any kind-normal acoustic or artificial intracochlear excitation-consists of not only a primary impulse but also a coda of delayed secondary responses with varying amplitudes but similar spectral content around the characteristic frequency of the measurement location. The coda, sometimes referred to as echoes or ringing, has been described as a form of local, short term memory which may influence the ability of the auditory system to detect gaps in an acoustic stimulus such as speech. Depending on the individual cochlea, the temporal gap between the primary impulse and the following coda ranges from once to thrice the group delay of the primary impulse (the group delay of the primary impulse is on the order of a few hundred microseconds. The coda is physiologically vulnerable, disappearing when the cochlea is compromised even slightly. The multicomponent sensitive response is not yet completely understood. We use a physiologically-based, mathematical model to investigate (i the generation of the primary impulse response and the dependence of the group delay on the various stimulation methods, (ii the effect of spatial perturbations in the properties of mechanically sensitive ion channels on the generation and separation of delayed secondary responses. The model suggests that the presence of the secondary responses depends on the wavenumber content of a perturbation and the activity level of the cochlea. In addition, the model shows that the varying temporal gaps between adjacent coda seen in experiments depend on the individual profiles of perturbations. Implications for non-invasive cochlear diagnosis are also discussed.

  3. Transient dynamic crack propagation in gas pressurised pipelines

    International Nuclear Information System (INIS)

    Caldis, E.S.; Owen, D.R.J.; Taylor, C.

    1983-01-01

    The prime limitation of dynamic fracture analysis is the lack of a fundamental crack advance theory which can be easily and economically adopted for use with numerical models. The necessity for the inclusion of inertia effects in the solution of certain problem classes is now evident, but most transient dynamic fracture models considered to date include (of necessity) some intuitive/empirical parameters with a frequent need of a priori knowledge of experimental solutions. The particular problem considered in this study is Mode I transient dynamic crack propagation in gas pressurised pipelines. The steel pipe is modelled using thin shell Semiloof finite elements and its transient response is coupled to a one-dimensional finite element model of the compressible gas equations, incorporating a lateral gas flow parameter. The pipe is governed by the usual dynamic equilibrium equation which is discretised in the time domain by a central difference explicit algorithm. The compressible gas response is modelled by the Continuity and Momentum equations and time discretisation is performed by means of a fully backward difference scheme in time. (orig./GL)

  4. The development of socially responsible life-sciences teachers through community service learning.

    Directory of Open Access Journals (Sweden)

    J.J. Rian de Villiers

    2012-03-01

    Full Text Available In South Africa, polices in higher education are urging tertiary institutions to produce graduates who are socially responsible citizens. One method of achieving this is through service-learning initiatives. Zoos as community partners can provide exciting educational opportunities for students to do animal behaviour studies and to develop their social responsibility. A sample of 58 preservice life-sciences teachers from a South African university completed a questionnaire on their animal behaviour studies. This study sought to determine how animal behaviour studies could successfully be incorporated as a community service-learning project in a zoo setting, what the educational value of these studies was and what the benefits were of incorporating this community service-learning component in the life-sciences course. The incorporation of the service-learning component into the zoology course led to the students’ personal and professional development, knowledge about themselves, sensitivity to cultural diversity, civic responsibility and insights into the ways in which communities operate. For a successful service-learning project, lectures, students and community partners should all have a sense of engagement. A number of suggestions are made to improve the incorporation of this service-learning component into the existing zoology course.

  5. Transient water stress in a vegetation canopy - Simulations and measurements

    Science.gov (United States)

    Carlson, Toby N.; Belles, James E.; Gillies, Robert R.

    1991-01-01

    Consideration is given to observational and modeling evidence of transient water stress, the effects of the transpiration plateau on the canopy radiometric temperature, and the factors responsible for the onset of the transpiration plateau, such as soil moisture. Attention is also given to the point at which the transient stress can be detected by remote measurement of surface temperature.

  6. Experimental Setup with Transient Behavior of Fuel Cladding of SFR

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Sang Hun; Kim, Jun Hwan; Kim, June-Hyung; Ryu, Woo Seog; Park, Sang Gyu; Kim, Sung Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    Nowadays, in Korea, advanced cladding such as FC92 is developed and its transient behaviors are required for the safety analysis of SFR. Design and safety analyses of sodium-cooled fast reactor (SFR) require understanding fuel pin responses to a wide range of off-normal events. In a loss-of-flow (LOF) or transient over-power (TOP), the temperature of the cladding is rapidly increased above its steady-state service temperature. Transient tests have been performed in sections of fuel pin cladding and a large data base has been established for austenitic stainless steel such as 20% cold-worked 316 SS and ferritic/martensitic steels such as HT9. This paper summarizes the technical status of transient testing facilities and their results. Previous researches showed the transient behaviors of HT9 cladding. For the safety analyses in SFR in Korea, simulated transient tests with newly developed FC92 as well as HT9 cladding are being carried out.

  7. Nonlinear transient responses of beams and rings to impulse loading or fragment impact

    International Nuclear Information System (INIS)

    Witmer, E.A.; Stagliano, T.R.; Rodal, J.J.A.

    1977-01-01

    The present paper is concerned with a very limited part of the cited fragment threat; namely, fragments from high speed rotating machinery such as (1) aircraft engine rotors and (2) stationary power plant turbine rotors. Further, it is assumed that the structures intended to contain or control these fragments consist of initially-isotropic elastic-plastic metals. Certain potential containment/control (C/C) structures behave in a planar (or two-dimensional) fashion while other fragment-attacked C/C structures will undergo general three-dimensional deformations. Predictions for only the former category of fragment-attacked structures are discussed in the present paper. Pertinent experimental data discussed here on fragment-attacked structures include (a) steel-sphere impact data involving beam targets and (b) engine rotor fragment impact against a steel containment ring. In all of these cases large-deflection, elastic-plastic transient structural response occur. The governing equations employed are presented in the present analysis to predict the responses of protective (metal) structures to engine-rotor-fragment impact. The protective structure is intended either to contain or to deflect the attacking fragments away from important regions; large-deflection, elasic-plastic structural response is expected because these protective structures must have the least feasible weight. Concise geometric and assumed-displacement-field descriptions of the several types of finite elements to be utilized in subsequent examples are given, together with several categories of strain displacement relations. Both low- and higher-order elements are discussed

  8. Cernavoda unit2 recirculated cooling water system transient analysis

    International Nuclear Information System (INIS)

    Nita, I. P.; Pancef, R.

    2015-01-01

    The paper is an approach to calculate the response of Cernavoda NPP Unit 2 RCW System to transient regimes during normal and abnormal regimes. Then one started to analyse the system response to reactor trip on class III and IV of power, LOCA on class IV of power, LOCA on class III power, LOIA on class IV of power, and LOIA on class III power. Moreover, one analysed the system transient due to requirement of changeover of a RCW operating pump, planned and unplanned changeover. This is the first transient approach to this system that took in consideration all building of the system, obtaining a very large system model, with over 900 pipe, 4 pumps, 50 consumers, 21 control valves. The changeover procedure was required to be analysed in order to change the nominal operating mode for Unit 2, from current 2 pumps in operation to 3 pump operations during summer operating mode. (authors)

  9. Opportunities for practical improvements in the management of plant transients

    International Nuclear Information System (INIS)

    Zebroski, E.L.

    1984-01-01

    This chapter attempts to provide some perspectives on the steps involved in analyzing, evaluating, and implementing remedies for transients and for potentially severe events. The importance of improved response and control of plant transients is stressed. The main steps involved in the attainment of improved control of plant transients are listed. Topics considered include the acquisition of plant data, sensitivity and risk analysis, the options for improvements, the managerial role, and some priorities for data, analysis, and evaluation. The ten most frequent types of transients for pressurized water reactors (PWRs) and boiling water reactors (BWRs) are listed according to frequency of occurrence. It is concluded that the two main needs of transient management are to avoid preoccupation with end-of-spectrum accidents and to improve the rate of technology transfer from best-available analysis and implementation

  10. Turbofan compressor dynamics during afterburner transients

    Science.gov (United States)

    Kurkov, A. P.

    1976-01-01

    The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.

  11. INVESTIGATING INDONESIAN EFL STUDENTS’ RESPONSES OF THE IMPLEMENTATION OF INTERCULTURAL LANGUAGE LEARNING

    Directory of Open Access Journals (Sweden)

    Fauzi Miftakh

    2015-12-01

    Full Text Available This study aimed at discovering the students‟ responses to the implementation of intercultural language learning at the sixth semester students of the English Education Department, University of Singaperbangsa Karawang, Indonesia. The focus of the study was on 1 the students‟ general attitudes toward the course, 2 the students‟ attitudes toward the implementation of teaching and learning and 3 the students‟ responsibility as an intercultural person. This study was designed as a descriptive qualitative study that involved 31 participants. The data were collected through questionnaire and interviews. Based on the findings, the students gave positive responses to the implementation of intercultural language learning and they showed a greater interest in participating in the course. The intercultural language learning also proved that the students were given the opportunity to become intercultural speakers either during the teaching and learning process or in their daily life. Finally, it recommends that the intercultural approach should be implemented by other English teachers in any subject and at all levels of students.

  12. The influence of attention and reward on the learning of stimulus-response associations

    NARCIS (Netherlands)

    Vartak, Devavrat; Jeurissen, Danique; Self, Matthew W; Roelfsema, Pieter R

    2017-01-01

    We can learn new tasks by listening to a teacher, but we can also learn by trial-and-error. Here, we investigate the factors that determine how participants learn new stimulus-response mappings by trial-and-error. Does learning in human observers comply with reinforcement learning theories, which

  13. How does feedback in mini-CEX affect students’ learning response?

    Science.gov (United States)

    Rahayu, Gandes Retno; Suhoyo, Yoyo

    2016-01-01

    Objective This study was aimed to explore students’ learning response toward feedback during mini-CEX encounter. Methods This study used a phenomenological approach to identify the students’ experiences toward feedback during mini-CEX encounter. Data was collected using Focus Group Discussion (FGD) for all students who were in their final week of clerkship in the internal medicine rotation. There were 4 FGD groups (6 students for each group). All FGD were audio-taped and transcribed verbatim. The FGD transcripts were analyzed thematically and managed using Atlas-ti (version 7.0). Results Feedback content and the way of providing feedback on mini-CEX stimulated students’ internal process, including self-reflection, emotional response, and motivation. These internal processes encouraged the students to take action or do a follow-up on the feedback to improve their learning process. In addition, there was also an external factor, namely consequences, which also influenced the students’ reaction to the follow-up on feedback. In the end, this action caused several learning effects that resulted in the students’ increased self-efficacy, attitude, knowledge and clinical skill. Conclusions Feedback content and the way of providing feedback on mini-CEX stimulates the students’ internal processes to do a follow-up on feedback. However, another external factor also affects the students’ decision on the follow-up actions. The follow-ups result in various learning effects on the students. Feedback given along with summative assessment enhances learning effects on students, as well. It is suggested that supervisors of clinical education are prepared to comprehend every factor influencing feedback on mini CEX to improve the students’ learning response. PMID:28008136

  14. Using Response Times to Assess Learning Progress: A Joint Model for Responses and Response Times

    Science.gov (United States)

    Wang, Shiyu; Zhang, Susu; Douglas, Jeff; Culpepper, Steven

    2018-01-01

    Analyzing students' growth remains an important topic in educational research. Most recently, Diagnostic Classification Models (DCMs) have been used to track skill acquisition in a longitudinal fashion, with the purpose to provide an estimate of students' learning trajectories in terms of the change of fine-grained skills overtime. Response time…

  15. Use of Constructed-Response Questions to Support Learning of Cell Biology during Lectures

    Directory of Open Access Journals (Sweden)

    Foong May Yeong

    2015-02-01

    Full Text Available The use of class-response systems such as the Clickers to promote active-learning during lectures has been wide-spread. However, the often-used MCQ format in class activities as well as in assessments for large classes might lower students’ expectations and attitudes towards learning. Here, I describe my experience converting MCQs to constructed-response questions for in-class learning activities by removing cues from the MCQs. From the responses submitted, students seemed capable of providing answers without the need for cues. Using class-response systems such as Socrative for such constructed-response questions could be useful to challenge students to express their ideas in their own words. Moreover, by constructing their own answers, mis-conceptions could be revealed and corrected in a timely manner.

  16. [Transient amnesia in the elderly].

    Science.gov (United States)

    Sellal, François

    2006-03-01

    The two main aetiologies of transient amnesia in the elderly are idiopathic transient global amnesia (TGA) and iatrogenic or toxic amnesia. Vascular and epileptic amnesia are less common. According to the literature, transient psychogenic amnesia, which is a frequent cause of amnesia at age 30 to 50, is very rare in the elderly. TGA is the prototypical picture of transient amnesia. It occurs more often after age 50, with no identified cause, even if some authors accept emotional stress or minor head trauma as occasional precipitants. The mechanism of TGA remains a matter of discussion. It may be the consequence of a spreading depression similar to that described in migraine with aura, but other arguments support an ischemic mechanism. Iatrogenic amnesias are mainly caused by benzodiazepines (BZs) or anticholinergics. The former may occur in a non-anxious subject, who is not a usual consumer of BZ and takes a single dose. The latter are more often due to a hypersensitivity to anticholinergic drugs, in particular in patients presenting with a covert, incipient Alzheimer's disease. A vascular origin must be considered when amnesia is accompanied by other neurological symptoms, and when the regression of the amnesic disorder is slow, lasting several days. It results from lesions involving various mechanisms and locations, mainly subcortical. Partial seizures, most often mesio-temporal, more rarely frontal, may be the cause of transient amnesia in the elderly, in the absence of a past history of epilepsy. The red flag supportive of an epileptic origin is the repetition of stereotyped amnesic episodes. EEG demonstration of seizures may be difficult and the response to antiepileptic drugs effective on partial seizures is usually good.

  17. Asteroids in the High Cadence Transient Survey

    Science.gov (United States)

    Peña, J.; Fuentes, C.; Förster, F.; Maureira, J. C.; San Martín, J.; Littín, J.; Huijse, P.; Cabrera-Vives, G.; Estévez, P. A.; Galbany, L.; González-Gaitán, S.; Martínez, J.; de Jaeger, Th.; Hamuy, M.

    2018-03-01

    We report on the serendipitous observations of solar system objects imaged during the High cadence Transient Survey 2014 observation campaign. Data from this high-cadence wide-field survey was originally analyzed for finding variable static sources using machine learning to select the most-likely candidates. In this work, we search for moving transients consistent with solar system objects and derive their orbital parameters. We use a simple, custom motion detection algorithm to link trajectories and assume Keplerian motion to derive the asteroid’s orbital parameters. We use known asteroids from the Minor Planet Center database to assess the detection efficiency of the survey and our search algorithm. Trajectories have an average of nine detections spread over two days, and our fit yields typical errors of {σ }a∼ 0.07 {au}, σ e ∼ 0.07 and σ i ∼ 0.°5 in semimajor axis, eccentricity, and inclination, respectively, for known asteroids in our sample. We extract 7700 orbits from our trajectories, identifying 19 near-Earth objects, 6687 asteroids, 14 Centaurs, and 15 trans-Neptunian objects. This highlights the complementarity of supernova wide-field surveys for solar system research and the significance of machine learning to clean data of false detections. It is a good example of the data-driven science that Large Synoptic Survey Telescope will deliver.

  18. Transient response of two lobe aerodynamic journal bearing

    Directory of Open Access Journals (Sweden)

    Saurabh Kumar Yadav

    2018-03-01

    Full Text Available The dynamic behavior of a rotor-dynamic system is greatly affected by the performance of aerodynamic bearing and the performance of bearing is characterized by the stiffness and damping coefficients. In the present work, stiffness and damping coefficients of bearing are computed and the performance of the bearing is greatly changed with the change in bearing air film profile. The effect of lobe offset factors on the transient performance of aerodynamic bearing is presented. Bifurcation and Poincare diagrams of two lobe journal bearing have been presented for different offset factors. A bearing designer can judge the bearing performance based on bifurcation diagrams.

  19. Transient reflectivity on vertically aligned single-wall carbon nanotubes

    NARCIS (Netherlands)

    Galimberti, Gianluca; Ponzoni, Stefano; Ferrini, Gabriele; Hofmann, Stephan; Arshad, Muhammad; Cepek, Cinzia; Pagliara, Stefania

    2013-01-01

    One-color transient reflectivity measurements are carried out on two different samples of vertically aligned single-wall carbon nanotube bundles and compared with the response recently published on unaligned bundles. The negative sign of the optical response for both samples indicates that the free

  20. Inferring the Mode of Selection from the Transient Response to Demographic Perturbations

    Science.gov (United States)

    Balick, Daniel; Do, Ron; Reich, David; Sunyaev, Shamil

    2014-03-01

    Despite substantial recent progress in theoretical population genetics, most models work under the assumption of a constant population size. Deviations from fixed population sizes are ubiquitous in natural populations, many of which experience population bottlenecks and re-expansions. The non-equilibrium dynamics introduced by a large perturbation in population size are generally viewed as a confounding factor. In the present work, we take advantage of the transient response to a population bottleneck to infer features of the mode of selection and the distribution of selective effects. We develop an analytic framework and a corresponding statistical test that qualitatively differentiates between alleles under additive and those under recessive or more general epistatic selection. This statistic can be used to bound the joint distribution of selective effects and dominance effects in any diploid sexual organism. We apply this technique to human population genetic data, and severely restrict the space of allowed selective coefficients in humans. Additionally, one can test a set of functionally or medically relevant alleles for the primary mode of selection, or determine the local regional variation in dominance coefficients along the genome.

  1. Analytical solution of transient temperature in continuous wave end-pumped laser slab: Reduction of temperature distribution and time of thermal response

    Directory of Open Access Journals (Sweden)

    Shibib Khalid S.

    2017-01-01

    Full Text Available An analytical solution of transient 3-D heat equation based on integral transform method is derived. The result are compared with numerical solution, and good agreements are obtained. Minimization of response time and temperature distribution through a laser slab are tested. It is found that the increasing in the lateral convection heat transfer coefficient can significantly reduce the response time and the temperature distribution while no effect on response time is observed when changing pumping profile from Gaussian to top hat beam in spite of the latter reduce the temperature distribution, also it is found that dividing the pumping power between two slab ends might reduce the temperature distribution and it has no effect on thermal response time.

  2. Transient photoresponse in amorphous In-Ga-Zn-O thin films under stretched exponential analysis

    Science.gov (United States)

    Luo, Jiajun; Adler, Alexander U.; Mason, Thomas O.; Bruce Buchholz, D.; Chang, R. P. H.; Grayson, M.

    2013-04-01

    We investigated transient photoresponse and Hall effect in amorphous In-Ga-Zn-O thin films and observed a stretched exponential response which allows characterization of the activation energy spectrum with only three fit parameters. Measurements of as-grown films and 350 K annealed films were conducted at room temperature by recording conductivity, carrier density, and mobility over day-long time scales, both under illumination and in the dark. Hall measurements verify approximately constant mobility, even as the photoinduced carrier density changes by orders of magnitude. The transient photoconductivity data fit well to a stretched exponential during both illumination and dark relaxation, but with slower response in the dark. The inverse Laplace transforms of these stretched exponentials yield the density of activation energies responsible for transient photoconductivity. An empirical equation is introduced, which determines the linewidth of the activation energy band from the stretched exponential parameter β. Dry annealing at 350 K is observed to slow the transient photoresponse.

  3. Transient behavior of redox flow battery connected to circuit based on global phase structure

    Science.gov (United States)

    Mannari, Toko; Hikihara, Takashi

    A Redox Flow Battery (RFB) is one of the promising energy storage systems in power grid. An RFB has many advantages such as a quick response, a large capacity, and a scalability. Due to these advantages, an RFB can operate in mixed time scale. Actually, it has been demonstrated that an RFB can be used for load leveling, compensating sag, and smoothing the output of the renewable sources. An analysis on transient behaviors of an RFB is a key issue for these applications. An RFB is governed by electrical, chemical, and fluid dynamics. The hybrid structure makes the analysis difficult. To analyze transient behaviors of an RFB, the exact model is necessary. In this paper, we focus on a change in a concentration of ions in the electrolyte, and simulate the change with a model which is mainly based on chemical kinetics. The simulation results introduces transient behaviors of an RFB in a response to a load variation. There are found three kinds of typical transient behaviors including oscillations. As results, it is clarified that the complex transient behaviors, due to slow and fast dynamics in the system, arise by the quick response to load.

  4. Spontaneous calcium transients in human neural progenitor cells mediated by transient receptor potential channels.

    Science.gov (United States)

    Morgan, Peter J; Hübner, Rayk; Rolfs, Arndt; Frech, Moritz J

    2013-09-15

    Calcium signals affect many developmental processes, including proliferation, migration, survival, and apoptosis, processes that are of particular importance in stem cells intended for cell replacement therapies. The mechanisms underlying Ca(2+) signals, therefore, have a role in determining how stem cells respond to their environment, and how these responses might be controlled in vitro. In this study, we examined the spontaneous Ca(2+) activity in human neural progenitor cells during proliferation and differentiation. Pharmacological characterization indicates that in proliferating cells, most activity is the result of transient receptor potential (TRP) channels that are sensitive to Gd(3+) and La(3+), with the more subtype selective antagonist Ruthenium red also reducing activity, suggesting the involvement of transient receptor potential vanilloid (TRPV) channels. In differentiating cells, Gd(3+) and La(3+)-sensitive TRP channels also appear to underlie the spontaneous activity; however, no sub-type-specific antagonists had any effect. Protein levels of TRPV2 and TRPV3 decreased in differentiated cells, which is demonstrated by western blot. Thus, it appears that TRP channels represent the main route of Ca(2+) entry in human neural progenitor cells (hNPCs), but the responsible channel types are subject to substitution under differentiating conditions. The level of spontaneous activity could be increased and decreased by lowering and raising the extracellular K(+) concentration. Proliferating cells in low K(+) slowed the cell cycle, with a disproportionate increased percentage of cells in G1 phase and a reduction in S phase. Taken together, these results suggest a link between external K(+) concentration, spontaneous Ca(2+) transients, and cell cycle distribution, which is able to influence the fate of stem and progenitor cells.

  5. Dynamic Response in Transient Stress-Field Behavior Induced by Hydraulic Fracturing

    Science.gov (United States)

    Jenkins, Andrew

    Hydraulic fracturing is a technique which is used to exploit geologic features and subsurface properties in an effort to increase production in low-permeability formations. The process of hydraulic fracturing provides a greater surface contact area between the producing formation and the wellbore and thus increases the amount of recoverable hydrocarbons from within the reservoir. The use of this stimulation technique has brought on massive applause from the industry due to its widespread success and effectiveness, however the dynamic processes that take part in the development of hydraulic fractures is a relatively new area of research with respect to the massive scale operations that are seen today. The process of hydraulic fracturing relies upon understanding and exploiting the in-situ stress distribution throughout the area of study. These in-situ stress conditions are responsible for directing fracture orientation and propagation paths throughout the period of injection. The relative magnitude of these principle stresses is key in developing a successful stimulation plan. In horizontal well plan development the interpretation of stress within the reservoir is required for determining the azimuth of the horizontal well path. These horizontal laterals are typically oriented in a manner such that the well path lies parallel to the minimum horizontal stress. This allows for vertical fractures to develop transversely to the wellbore, or normal to the least principle stress without the theoretical possibility of fractures overlapping, creating the most efficient use of the fluid energy during injection. The orientation and magnitude of these in-situ stress fields however can be dynamic, controlled by the subsequent fracture propagation and redistribution of the surrounding stresses. That is, that as the fracture propagates throughout the reservoir, the relative stress fields surrounding the fractures may see a shift and deviate from their original direction or

  6. Equivalent circuit simulation of HPEM-induced transient responses at nonlinear loads

    Directory of Open Access Journals (Sweden)

    M. Kotzev

    2017-09-01

    Full Text Available In this paper the equivalent circuit modeling of a nonlinearly loaded loop antenna and its transient responses to HPEM field excitations are investigated. For the circuit modeling the general strategy to characterize the nonlinearly loaded antenna by a linear and a nonlinear circuit part is pursued. The linear circuit part can be determined by standard methods of antenna theory and numerical field computation. The modeling of the nonlinear circuit part requires realistic circuit models of the nonlinear loads that are given by Schottky diodes. Combining both parts, appropriate circuit models are obtained and analyzed by means of a standard SPICE circuit simulator. It is the main result that in this way full-wave simulation results can be reproduced. Furthermore it is clearly seen that the equivalent circuit modeling offers considerable advantages with respect to computation speed and also leads to improved physical insights regarding the coupling between HPEM field excitation and nonlinearly loaded loop antenna.

  7. The Neural Feedback Response to Error As a Teaching Signal for the Motor Learning System

    Science.gov (United States)

    Shadmehr, Reza

    2016-01-01

    When we experience an error during a movement, we update our motor commands to partially correct for this error on the next trial. How does experience of error produce the improvement in the subsequent motor commands? During the course of an erroneous reaching movement, proprioceptive and visual sensory pathways not only sense the error, but also engage feedback mechanisms, resulting in corrective motor responses that continue until the hand arrives at its goal. One possibility is that this feedback response is co-opted by the learning system and used as a template to improve performance on the next attempt. Here we used electromyography (EMG) to compare neural correlates of learning and feedback to test the hypothesis that the feedback response to error acts as a template for learning. We designed a task in which mixtures of error-clamp and force-field perturbation trials were used to deconstruct EMG time courses into error-feedback and learning components. We observed that the error-feedback response was composed of excitation of some muscles, and inhibition of others, producing a complex activation/deactivation pattern during the reach. Despite this complexity, across muscles the learning response was consistently a scaled version of the error-feedback response, but shifted 125 ms earlier in time. Across people, individuals who produced a greater feedback response to error, also learned more from error. This suggests that the feedback response to error serves as a teaching signal for the brain. Individuals who learn faster have a better teacher in their feedback control system. SIGNIFICANCE STATEMENT Our sensory organs transduce errors in behavior. To improve performance, we must generate better motor commands. How does the nervous system transform an error in sensory coordinates into better motor commands in muscle coordinates? Here we show that when an error occurs during a movement, the reflexes transform the sensory representation of error into motor

  8. Application of response theory to steam venting during a loss of AC power transient

    Energy Technology Data Exchange (ETDEWEB)

    Cady, K.B.; Miller, R.J.

    1987-05-01

    We have applied the theory of response to the loss of AC power transient for an LMFBR design to determine the ultimate loss of coolant inventory and the sensitivity of this figure with respect to the initial conditions and input parameters. Using a simple four region heat transfer model, the analysis shows that 3717 kg coolant are vented after feed water is lost and before venting stops. The sensitivity analysis reveals that this figure is strongly dependent on design parameters and system assumptions. The uncertainty in the lost inventory caused by the uncertainties and correlations in the input parameters and initial conditions is found to be 3464 kg. We thus report the result of the calculation as lost inventory (kg)=3717+-3464 and conclude that the available inventory of 8775 kg is sufficient to ensure an adequate heat sink.

  9. Cortical computations via transient attractors.

    Directory of Open Access Journals (Sweden)

    Oliver L C Rourke

    Full Text Available The ability of sensory networks to transiently store information on the scale of seconds can confer many advantages in processing time-varying stimuli. How a network could store information on such intermediate time scales, between typical neurophysiological time scales and those of long-term memory, is typically attributed to persistent neural activity. An alternative mechanism which might allow for such information storage is through temporary modifications to the neural connectivity which decay on the same second-long time scale as the underlying memories. Earlier work that has explored this method has done so by emphasizing one attractor from a limited, pre-defined set. Here, we describe an alternative, a Transient Attractor network, which can learn any pattern presented to it, store several simultaneously, and robustly recall them on demand using targeted probes in a manner reminiscent of Hopfield networks. We hypothesize that such functionality could be usefully embedded within sensory cortex, and allow for a flexibly-gated short-term memory, as well as conferring the ability of the network to perform automatic de-noising, and separation of input signals into distinct perceptual objects. We demonstrate that the stored information can be refreshed to extend storage time, is not sensitive to noise in the system, and can be turned on or off by simple neuromodulation. The diverse capabilities of transient attractors, as well as their resemblance to many features observed in sensory cortex, suggest the possibility that their actions might underlie neural processing in many sensory areas.

  10. Transient fuel rod behavior prediction with RODEX-3/SIERRA

    Energy Technology Data Exchange (ETDEWEB)

    Billaux, M R; Shann, S H; Swam, L.F. Van [Siemens Power Corp., Richland, WA (United States)

    1997-08-01

    This paper discusses some aspects of the fuel performance code SIERRA (SIEmens Rod Response Analysis). SIERRA, the latest version of the code RODEX-3, has been developed to improve the fuel performance prediction capabilities of the code, both at high burnup and during transient reactor conditions. The paper emphasizes the importance of the mechanical models of the cracked pellet and of the cladding, in the prediction of the transient response of the fuel rod to power changes. These models are discussed in detail. Other aspects of the modelling of high burnup effects are also presented, in particular the modelling of the rim effect and the way it affects the fuel temperature. (author). 12 refs, 5 figs.

  11. Transient fuel rod behavior prediction with RODEX-3/SIERRA

    International Nuclear Information System (INIS)

    Billaux, M.R.; Shann, S.H.; Swam, L.F. Van

    1997-01-01

    This paper discusses some aspects of the fuel performance code SIERRA (SIEmens Rod Response Analysis). SIERRA, the latest version of the code RODEX-3, has been developed to improve the fuel performance prediction capabilities of the code, both at high burnup and during transient reactor conditions. The paper emphasizes the importance of the mechanical models of the cracked pellet and of the cladding, in the prediction of the transient response of the fuel rod to power changes. These models are discussed in detail. Other aspects of the modelling of high burnup effects are also presented, in particular the modelling of the rim effect and the way it affects the fuel temperature. (author). 12 refs, 5 figs

  12. Learning not to respond: Role of the hippocampus in withholding responses during omission training.

    Science.gov (United States)

    White, Norman M; Naeem, Maliha

    2017-02-01

    Autoshaping is a Pavlovian learning paradigm in which rats experience pairings of a CS and a US independently of their behavior. When the CS is a lever inserted into the test cage and the US is food delivered to an adjacent magazine, many rats acquire a lever-pressing response called 'sign-tracking' even though that response has no effect on the occurrence of either the CS or the US. Since these lever presses are always followed by the US, it has been suggested that sign-tracking could be due to unintended reinforcement of the response. To eliminate the possibility of such instrumental learning the omission schedule, in which a response to the CS cancels the US, was introduced. Previous research has shown that training rats on autoshaping and switching them to an omission schedule generally reduces but does not eliminate sign-tracking, suggesting that it may be due to both Pavlovian and instrumental learning. In the present study naive rats trained on an omission schedule sign-tracked less than a control group exposed to random, unpaired CS and US presentations, suggesting that they learned to withhold the lever press response because of the negative contingency between that response and the US. In a second experiment rats with dorsal hippocampus lesions sign-tracked more than sham-lesioned rats on omission schedules, suggesting that this case of learning not to respond is hippocampus-based. This conclusion is consistent with many previous findings on the inability of hippocampal rats to withhold or suppress responding, and with studies suggesting that one form of extinction of learned responses in normal rats is due to competition from hippocampus-based learning not to respond. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Transient Go: A Mobile App for Transient Astronomy Outreach

    Science.gov (United States)

    Crichton, D.; Mahabal, A.; Djorgovski, S. G.; Drake, A.; Early, J.; Ivezic, Z.; Jacoby, S.; Kanbur, S.

    2016-12-01

    Augmented Reality (AR) is set to revolutionize human interaction with the real world as demonstrated by the phenomenal success of `Pokemon Go'. That very technology can be used to rekindle the interest in science at the school level. We are in the process of developing a prototype app based on sky maps that will use AR to introduce different classes of astronomical transients to students as they are discovered i.e. in real-time. This will involve transient streams from surveys such as the Catalina Real-time Transient Survey (CRTS) today and the Large Synoptic Survey Telescope (LSST) in the near future. The transient streams will be combined with archival and latest image cut-outs and other auxiliary data as well as historical and statistical perspectives on each of the transient types being served. Such an app could easily be adapted to work with various NASA missions and NSF projects to enrich the student experience.

  14. On-line transient stability assessment of large-scale power systems by using ball vector machines

    International Nuclear Information System (INIS)

    Mohammadi, M.; Gharehpetian, G.B.

    2010-01-01

    In this paper ball vector machine (BVM) has been used for on-line transient stability assessment of large-scale power systems. To classify the system transient security status, a BVM has been trained for all contingencies. The proposed BVM based security assessment algorithm has very small training time and space in comparison with artificial neural networks (ANN), support vector machines (SVM) and other machine learning based algorithms. In addition, the proposed algorithm has less support vectors (SV) and therefore is faster than existing algorithms for on-line applications. One of the main points, to apply a machine learning method is feature selection. In this paper, a new Decision Tree (DT) based feature selection technique has been presented. The proposed BVM based algorithm has been applied to New England 39-bus power system. The simulation results show the effectiveness and the stability of the proposed method for on-line transient stability assessment procedure of large-scale power system. The proposed feature selection algorithm has been compared with different feature selection algorithms. The simulation results demonstrate the effectiveness of the proposed feature algorithm.

  15. Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals.

    Science.gov (United States)

    Reynolds, Gemma; Field, Andy P; Askew, Chris

    2014-10-01

    Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang's anxiety response systems and is sufficient to create attentional bias to threat in children. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  16. LMFBR. Off normal, transient test facilities and programs in the USA

    International Nuclear Information System (INIS)

    Herbst, R.J.

    1985-01-01

    The United States fast breeder reactor development program has included operational transient analyses and experiments to verify the predicted performance of core components. Operational transient testing has focused on off-normal operation during Plant Protection System terminated transient-overpower events. In-pile and out-of-pile tests have been used to simulate predicted thermal and mechanical strain cycles and measure component response. The spectrum of reactivity ramp rates investigated in TOP tests has recently been expanded to include rates of less than $0.1/s. These slow ramp rate studies are being done in cooperation with the Japanese. The US has also cooperated with the UK in the transient testing of Prototype Fast Reactor fuel pins

  17. University EFL Learners' Perceptions of Their Autonomous Learning Responsibilities and Abilities

    Science.gov (United States)

    Abdel Razeq, Anwar Ahmad

    2014-01-01

    This study investigated the readiness of university students for autonomous learning of English as a foreign language. Data was collected using questionnaires and interviews. The study assessed learners' readiness for autonomous learning across three dimensions: a) learners' perceptions of their educational responsibilities; b) learners' abilities…

  18. Modeling transient radiation effects in power MOSFETS

    International Nuclear Information System (INIS)

    Hoffman, J.R.; Hall, W.E.; Dunn, D.E.

    1987-01-01

    Using standard device specifications and simple assumptions, the transient radiation response of VDMOS MOSFETs can be modeled in a standard circuit analysis program. The device model consists of a body diode, a parasitic bipolar transistor, and elements to simulate high-current reduced breakdown. The attached photocurrent model emulates response to any pulse shape and accounts for bias-dependent depletion regions. The model can be optimized to best fit available test data

  19. Response of centrifugal blowers to simulated tornado transients, July-September 1981

    International Nuclear Information System (INIS)

    Idar, E.S.; Gregory, W.S.; Martin, R.A.; Littleton, P.E.

    1982-03-01

    During this quarter, quasi-steady and dynamic testing of the 24-in. centrifugal blower was completed using the blowdown facility located at New Mexico State University. The data were obtained using a new digital data-acquisition system. Software was developed at the Los Alamos National Laboratory to reduce the dynamic test data and create computer-generated movies showing the dynamic performance of the blower under simulated tornado transient pressure conditions relative to its quasi-steady-state performance. Currently, quadrant-four (outrunning flow) data have been reduced for the most severe and a less severe tornado pressure transient. The results indicate that both the quasi-steady and dynamic blower performance are very similar. Some hysteresis in the dynamic performance occurs because of rotational inertia effects in the blower rotor and drive system. Currently quadrant-two (backflow) data are being transferred to the LTSS computer system at Los Alamos and will be reduced shortly

  20. Mere exposure effect can be elicited in transient global amnesia.

    Science.gov (United States)

    Marin-Garcia, Eugenia; Ruiz-Vargas, Jose M; Kapur, Narinder

    2013-01-01

    Transient global amnesia (TGA) is one of the most severe forms of anterograde amnesia seen in clinical practice, yet patients may show evidence of spared learning during the amnesic episode. The scope of spared learning in such a severe form of amnesia remains uncertain, and it is also unclear whether findings from single-case studies hold up in group studies of TGA patients. In this group study, we found evidence that extended the domain of spared learning in TGA to include the mere exposure effect, whereby enhanced preference is primed by prior exposure to stimuli. We demonstrate this effect during an acute episode in a group of TGA patients, where they showed enhanced preference for previously exposed faces, despite markedly impaired performance on standard anterograde memory tests.

  1. Four RNA families with functional transient structures.

    Science.gov (United States)

    Zhu, Jing Yun A; Meyer, Irmtraud M

    2015-01-01

    Protein-coding and non-coding RNA transcripts perform a wide variety of cellular functions in diverse organisms. Several of their functional roles are expressed and modulated via RNA structure. A given transcript, however, can have more than a single functional RNA structure throughout its life, a fact which has been previously overlooked. Transient RNA structures, for example, are only present during specific time intervals and cellular conditions. We here introduce four RNA families with transient RNA structures that play distinct and diverse functional roles. Moreover, we show that these transient RNA structures are structurally well-defined and evolutionarily conserved. Since Rfam annotates one structure for each family, there is either no annotation for these transient structures or no such family. Thus, our alignments either significantly update and extend the existing Rfam families or introduce a new RNA family to Rfam. For each of the four RNA families, we compile a multiple-sequence alignment based on experimentally verified transient and dominant (dominant in terms of either the thermodynamic stability and/or attention received so far) RNA secondary structures using a combination of automated search via covariance model and manual curation. The first alignment is the Trp operon leader which regulates the operon transcription in response to tryptophan abundance through alternative structures. The second alignment is the HDV ribozyme which we extend to the 5' flanking sequence. This flanking sequence is involved in the regulation of the transcript's self-cleavage activity. The third alignment is the 5' UTR of the maturation protein from Levivirus which contains a transient structure that temporarily postpones the formation of the final inhibitory structure to allow translation of maturation protein. The fourth and last alignment is the SAM riboswitch which regulates the downstream gene expression by assuming alternative structures upon binding of SAM. All

  2. Teacher response to learning disability: a test of attributional principles.

    Science.gov (United States)

    Clark, M D

    1997-01-01

    Attribution research has identified student ability and effort expended as causes of achievement outcomes that result in differing teacher affect, evaluative feedback, and expectation of future performance. Ninety-seven elementary-school general education teachers (84 women and 13 men) rated their responses to the test failures of hypothetical boys with and without learning disabilities. In most cases, greater reward and less punishment, less anger and more pity, and higher expectations of future failure followed the negative outcomes of the boys with learning disabilities, when compared with their nondisabled ability and effort matches, indicating that learning disability acts as a cause of achievement outcomes in the same way as ability and effort. This pattern of teacher affect and response can send negative messages that are often interpreted as low-ability cues, thus affecting students' self-esteem, sense of competence as learners, and motivation to achieve.

  3. Heart rate response to post-learning stress predicts memory consolidation.

    Science.gov (United States)

    Larra, Mauro F; Schulz, André; Schilling, Thomas M; Ferreira de Sá, Diana S; Best, Daniel; Kozik, Bartlomiej; Schächinger, Hartmut

    2014-03-01

    Stressful experiences are often well remembered, an effect that has been explained by beta-adrenergic influences on memory consolidation. Here, we studied the impact of stress induced heart rate (HR) responses on memory consolidation in a post-learning stress paradigm. 206 male and female participants saw 52 happy and angry faces immediately before being exposed to the Cold Pressor Test or a non-stressful control procedure. Memory for the faces and their respective expression was tested twice, after 30 min and on the next day. High HR responders (in comparison to low HR responders as well as to the non-stressful control group) showed enhanced recognition memory one day after learning. Our results show that beta-adrenergic activation elicited shortly after learning enhances memory consolidation and that the stress induced HR response is a predictor for this effect. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Numerical simulations of subcritical reactor kinetics in thermal hydraulic transient phases

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J; Park, W S [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-12-31

    A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute (KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons, external neutrons form spallation reactions are essentially required for operating the reactor in its steady state. Furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance to the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases. 5 refs., 8 figs. (Author)

  5. Numerical simulations of subcritical reactor kinetics in thermal hydraulic transient phases

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, J.; Park, W. S. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A subcritical reactor driven by a linear proton accelerator has been considered as a nuclear waste incinerator at Korea Atomic Energy Research Institute (KAERI). Since the multiplication factor of a subcritical reactor is less than unity, to compensate exponentially decreasing fission neutrons, external neutrons form spallation reactions are essentially required for operating the reactor in its steady state. Furthermore, the profile of accelerator beam currents is very important in controlling a subcritical reactor, because the reactor power varies in accordance to the profile of external neutrons. We have developed a code system to find numerical solutions of reactor kinetics equations, which are the simplest dynamic model for controlling reactors. In a due course of our previous numerical study of point kinetics equations for critical reactors, however, we learned that the same code system can be used in studying dynamic behavior of the subcritical reactor. Our major motivation of this paper is to investigate responses of subcritical reactors for small changes in thermal hydraulic parameters. Building a thermal hydraulic model for the subcritical reactor dynamics, we performed numerical simulations for dynamic responses of the reactor based on point kinetics equations with a source term. Linearizing a set of coupled differential equations for reactor responses, we focus our research interest on dynamic responses of the reactor to variations of the thermal hydraulic parameters in transient phases. 5 refs., 8 figs. (Author)

  6. Development of a transient photocurrent response method for non-destructive analysis of defects in solar cells; Entwicklung einer Transient Photocurrent Response-Methode zur zerstoerungsfreien Untersuchung von Stoerstellen in Solarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Sperling, A

    1995-01-01

    A new measuring method for the destruction-free characterisation of impurities in basically large-surface [(20x20) mm{sup 2}]solar cells or photo detectors is explained. During this TPCR measuring method the transient photocurrent signal, generated by a repeating, rectangular, monochromatic irradiation, is recorded in dependence on the darkness between the irradiation pulses and on the temperature of the cells. (orig.) [Deutsch] Es wird ein neues Messverfahren zur zerstoerungsfreien Charakterisierung von Verunreinigungen in der Basis grossflaechiger [(20x20) mm{sup 2}] Solarzellen bzw. Photodetektoren vorgestellt. Bei diesem TPCR-Messverfahren wird das durch eine repetierende, rechteckfoermige, monochromatische Bestrahlung erzeugte transiente Photostrom-Signal in Abhaengigkeit von der Dunkelzeit zwischen den Bestrahlungspulsen und von der Tempeatur der Zelle aufgenommen. (orig./HW)

  7. Unification of three linear models for the transient visual system

    NARCIS (Netherlands)

    Brinker, den A.C.

    1989-01-01

    Three different linear filters are considered as a model describing the experimentally determined triphasic impulse responses of discs. These impulse responses arc associated with the transient visual system. Each model reveals a different feature of the system. Unification of the models is

  8. Differential effects of massed and spaced training on place and response learning: A memory systems perspective.

    Science.gov (United States)

    Wingard, Jeffrey C; Goodman, Jarid; Leong, Kah-Chung; Packard, Mark G

    2015-09-01

    Studies employing brain lesion or intracerebral drug infusions in rats have demonstrated a double dissociation between the roles of the hippocampus and dorsolateral striatum in place and response learning. The hippocampus mediates a rapid cognitive learning process underlying place learning, whereas the dorsolateral striatum mediates a relatively slower learning process in which stimulus-response habits underlying response learning are acquired in an incremental fashion. One potential implication of these findings is that hippocampus-dependent learning may benefit from a relative massing of training trials, whereas dorsal striatum-dependent learning may benefit from a relative distribution of training trials. In order to examine this hypothesis, the present study compared the effects of massed (30s inter-trial interval; ITI) or spaced (30min ITI) training on acquisition of a hippocampus-dependent place learning task, and a dorsolateral striatum-dependent response task in a plus-maze. In the place task rats swam from varying start points (N or S) to a hidden escape platform located in a consistent spatial location (W). In the response task rats swam from varying start points (N or S) to a hidden escape platform located in the maze arm consistent with a body-turn response (left). In the place task, rats trained with the massed trial schedule acquired the task quicker than rats trained with the spaced trial schedule. In the response task, rats trained with the spaced trial schedule acquired the task quicker than rats trained with the massed trial schedule. The double dissociation observed suggests that the reinforcement parameters most conducive to effective learning in hippocampus-dependent and dorsolateral striatum-dependent learning may have differential temporal characteristics. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Spill response exercises and lessons learned : a response organization's perspective

    International Nuclear Information System (INIS)

    Taylor, E.; Green, M.

    2001-01-01

    In the past five years, Burrard Clean Operations (BCO) has demonstrated its' oil spill response capabilities through different types of exercises. Such exercises are necessary for certification of Response Organizations in Canada. The exercises can be performed through actual response to spills or through simulated situations. Both can provide an opportunity to practice different levels of response to a range of conditions in various settings. They also provide the opportunity to focus on specific themes that can be part of a response and to identify areas for improvement in response actions. They also make it possible to interface with government agencies, industry and others that participate in spill responses. The exercise program for BCO is aimed at maintaining certification and to assist the Canadian Coast Guard. The exercises broaden the lessons learned and set a course for future enhancement to spill readiness should a real incident occur. The goals of the exercise program are to provide real time drills that show the operational capability of a representative sample of BCO equipment, management and trained spill responders. The response functions of the BCO exercise program are: notification, response organization activation, contractor activation, situation analysis, strategy development for marine oil spill response, site safety, equipment deployment, containment, recovery, shoreline assessment, cleanup, communications, decontamination, logistics, and financial management. The BCO experience has led to the basic conclusions that there is a need to vary the exercise design and format and that there is a need to implement follow-up actions provided during exercise evaluations. 7 refs., 3 tabs

  10. Understanding the Slow Transient Optoelectronic Response of Hybrid Organic-Inorganic Halide Perovskites

    Science.gov (United States)

    Jacobs, Daniel Louis

    Hybrid organic-inorganic halide perovskites, particularly methylammonium lead triiodide (MAPbI3), have emerged within the past decade as an exciting class of photovoltaic materials. In less than ten years, MAPbI3-based photovoltaic devices have seen unprecedented performance growth, with photoconversion efficiency increasing from 3% to over 22%, making it competitive with traditional high-efficiency solar cells. Furthermore, the fabrication of MAPbI3 devices utilize low-temperature solution processing, which could facilitate ultra low cost manufacturing. However, MAPbI3 suffers from significant instabilities under working conditions that have limited their applications outside of the laboratory. The instability of the MAPbI3 material can be generalized as a complex, slow transient optoelectronic response (STOR). The mechanism of the generalized STOR is dependent on the native defects of MAPbI3, but detailed understanding of the material defect properties is complicated by the complex ionic bonding of MAPbI3. Furthermore, characterization of the intrinsic material's response is complicated by the diverse approach to material processing and device architecture across laboratories around the world. In order to understand and mitigate the significant problems of MAPbI3 devices, a new approach focused on the material response, rather than the full device response, must be pursued. This dissertation highlights the work to analyze and mitigate the STOR intrinsic to MAPbI3. An experimental platform was developed based on lateral interdigitated electrode (IDE) arrays capable of monitoring the current and photoluminescence response simultaneously. By correlating the dynamics of the current and photoluminescence (PL) responses, both charge trapping and ion migration mechanisms were identified to contribute to the STOR. Next, a novel fabrication technique is introduced that is capable of reliably depositing MAPbI3 thin films with grain sizes at least an order of magnitude

  11. Study of a spur gear dynamic behavior in transient regime

    Science.gov (United States)

    Khabou, M. T.; Bouchaala, N.; Chaari, F.; Fakhfakh, T.; Haddar, M.

    2011-11-01

    In this paper the dynamic behavior of a single stage spur gear reducer in transient regime is studied. Dynamic response of the single stage spur gear reducer is investigated at different rotating velocities. First, gear excitation is induced by the motor torque and load variation in addition to the fluctuation of meshing stiffness due to the variation of input rotational speed. Then, the dynamic response is computed using the Newmark method. After that, a parameter study is made on spur gear powered in the first place by an electric motor and in the second place by four strokes four cylinders diesel engine. Dynamic responses come to confirm a significant influence of the transient regime on the dynamic behavior of a gear set, particularly in the case of engine acyclism condition.

  12. Geometrical considerations in the transient ionization testing of digital logic circuits

    International Nuclear Information System (INIS)

    Johnston, A.

    1982-01-01

    Mechanisms are identified that can cause the transient response of digital logic circuits to depend on the logic state in which they are irradiated. Several of these mechanisms depend on surface topology, and for these cases the sensitive logic states can be determined by examining the topology. General approaches for transient radiation testing are also discussed for several MSI and LSI device technologies

  13. Mechanical modelling of transient- to- failure SFR fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Feria, F.; Herranz, L. E.

    2014-07-01

    The response of Sodium Fast Reactor (SFR) fuel rods to transient accident conditions is an important safety concern. During transients the cladding strain caused by the stress due to pellet cladding mechanical interaction (PCMI) can lead to failure. Due to the fact that SFR fuel rods are commonly clad with strengthened material made of stainless steel (SS), cladding is usually treated as an elastic-perfectly-plastic material. However, viscoplastic behaviour can contribute to mechanical strain at high temperature (> 1000 K). (Author)

  14. Transient analysis of LMFBR reinforced/prestressed concrete containment

    International Nuclear Information System (INIS)

    Marchertas, A.H.; Belytschko, T.B.; Bazant, Z.P.

    1979-01-01

    The use of prestressed concrete reactor vessels (PCRVs) for LMFBR containment creates a need for analytical methods for treating the transient response of such structures, for LMFBR containments must be capable of sustaining the dynamic effects which arise in a hypothetical core disruptive accident (HCDA). These analyses require several unique features: a model of concrete which includes tensile cracking, a methodology for representing the prestressing tendons and for simulating the prestressing operation, and an efficient computational tool for treating the transient response. Furthermore, for the sake of convenience, all of these features should be available in a single computer code. For the purpose of treating the transient response, a finite element program with explicit time integration was chosen. The use of explicit time integration has the advantage that it can easily treat the complicated constitutive model which arises from the considerations of concrete cracking and it can handle the slip between reinforcing tendons and the concrete through the use of the well known sliding interface options. However, explicit time integration programs are usually not well suited to the simulation of static processes such as prestressing. Nevertheless, explicit time integration programs can handle static processes through the introduction of damping by what is known as a dynamic relaxation procedure. For this reason, the dynamic relaxation procedure was refined through the introduction of lumped mass, viscous damping. This provision made the prestressing operation of the concrete structures by means of the explicit formulation rather convenient. (orig.)

  15. Aeroelastic Modeling of a Nozzle Startup Transient

    Science.gov (United States)

    Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen

    2014-01-01

    Lateral nozzle forces are known to cause severe structural damage to any new rocket engine in development during test. While three-dimensional, transient, turbulent, chemically reacting computational fluid dynamics methodology has been demonstrated to capture major side load physics with rigid nozzles, hot-fire tests often show nozzle structure deformation during major side load events, leading to structural damages if structural strengthening measures were not taken. The modeling picture is incomplete without the capability to address the two-way responses between the structure and fluid. The objective of this study is to develop a tightly coupled aeroelastic modeling algorithm by implementing the necessary structural dynamics component into an anchored computational fluid dynamics methodology. The computational fluid dynamics component is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, while the computational structural dynamics component is developed under the framework of modal analysis. Transient aeroelastic nozzle startup analyses at sea level were performed, and the computed transient nozzle fluid-structure interaction physics presented,

  16. Anticipated transient without SCRAM experiments at LOFT

    International Nuclear Information System (INIS)

    Grush, W.H.; Harvego, E.A.; Koizumi, Y.; Varacalle, D.J.

    1983-01-01

    This paper discusses the experimental results for two anticipated transients without scram (ATWS) experiments, and compares computer code predictions with the experimental data. Experiment L9-3 simulated an ATWS in a commercial pressurized water reactor (PWR) initiated by a complete loss of feedwater and Experiment L9-4 simulated a loss-of-offsite-power-initiated (loss of feedwater and trip of the primary coolant pumps) ATWS. The LOFT facility is uniquely suited for ATWS experiments because it is a volumetrically scaled (1/44) experimental PWR designed to simulate the major components and system responses of larger commercial PWRs during both hypothesized loss-of-coolant accidents and anticipated transients. In both of the examined experiments, the primary system transient behavior was dominated by the interactions between the steam generator primary-to-secondary heat removal, the reactor kinetics, and the relief valve actuation. It is demonstrated that the discussed ATWS events can be controlled by properly sized automatic safety systems

  17. Analytical solution for the transient response of a fluid/saturated porous medium halfspace system subjected to an impulsive line source

    Science.gov (United States)

    Shan, Zhendong; Ling, Daosheng; Jing, Liping; Li, Yongqiang

    2018-05-01

    In this paper, transient wave propagation is investigated within a fluid/saturated porous medium halfspace system with a planar interface that is subjected to a cylindrical P-wave line source. Assuming the permeability coefficient is sufficiently large, analytical solutions for the transient response of the fluid/saturated porous medium halfspace system are developed. Moreover, the analytical solutions are presented in simple closed forms wherein each term represents a transient physical wave, especially the expressions for head waves. The methodology utilised to determine where the head wave can emerge within the system is also given. The wave fields within the fluid and porous medium are first defined considering the behaviour of two compressional waves and one tangential wave in the saturated porous medium and one compressional wave in the fluid. Substituting these wave fields into the interface continuity conditions, the analytical solutions in the Laplace domain are then derived. To transform the solutions into the time domain, a suitable distortion of the contour is provided to change the integration path of the solution, after which the analytical solutions in the Laplace domain are transformed into the time domain by employing Cagniard's method. Numerical examples are provided to illustrate some interesting features of the fluid/saturated porous medium halfspace system. In particular, the interface wave and head waves that propagate along the interface between the fluid and saturated porous medium can be observed.

  18. Power System Transient Stability Improvement Using Demand Side Management in Competitive Electricity Markets

    DEFF Research Database (Denmark)

    Hu, Weihao; Wang, Chunqi; Chen, Zhe

    2012-01-01

    Since the hourly spot market price is available one day ahead in Denmark, the price could be transferred to the consumers and they may shift some of their loads from high price periods to the low price periods in order to save their energy costs. The optimal load response to an electricity price...... for demand side management generates different load profiles and may provide an opportunity to improve the transient stability of power systems with high wind power penetrations. In this paper, the idea of the power system transient stability improvement by using optimal load response to the electricity...... price is proposed. A 102-bus power system which represents a simplified model of the western Danish power system is chosen as the study case. Simulation results show that the optimal load response to electricity prices is an effective measure to improve the power system transient stability with high...

  19. Cardiac Autonomic Modulation and the Kinetics of Heart Rate Responses in the On- and Off-Transient during Exercise in Women with Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Lucas R. B. E. Silva

    2017-07-01

    Full Text Available Objective: To test whether women with metabolic syndrome (MS have impairments in the on- and off-transients during an incremental test and to study whether any of the MS components are independently associated with the observed responses.Research Design and Methods: Thirty-six women aged 35–55 years were divided into a group with MS (MSG, n = 19 and a control group (CG, n = 17. R-R intervals (RRi and heart rate variability (HRV were calculated on a beat-to-beat basis and the heart rate (HR at the on- and off-transient were analyzed during an incremental cardiopulmonary exercise test (CPET.Results: MSG showed lower aerobic capacity and lower parasympathetic cardiac modulation at rest compared with CG. HR values in on-transient phase were significantly lower in MSG compared with CG. The exponential amplitudes “amp” and the parameters “τ” [speed of heart rate recovery (HRR] were lower in MSG. MSG exhibited higher HR values in comparison to CG during the off-transient indicating a slower HRR. In MSG, there was an inverse and significant correlation between fasting plasma vs. ΔF and glucose vs. exponential “τ” of HRR dynamics.Conclusion: MS is associated with poor heart rate kinetics. The altered HR kinetics seems to be related to alterations in cardiac parasympathetic modulation, and glucose metabolism seems to be the major determinant.

  20. Loss of Transient Receptor Potential Ankyrin 1 Channel Deregulates Emotion, Learning and Memory, Cognition, and Social Behavior in Mice.

    Science.gov (United States)

    Lee, Kuan-I; Lin, Hui-Ching; Lee, Hsueh-Te; Tsai, Feng-Chuan; Lee, Tzong-Shyuan

    2017-07-01

    The transient receptor potential ankyrin 1 (TRPA1) channel is a non-selective cation channel that helps regulate inflammatory pain sensation and nociception and the development of inflammatory diseases. However, the potential role of the TRPA1 channel and the underlying mechanism in brain functions are not fully resolved. In this study, we demonstrated that genetic deletion of the TRPA1 channel in mice or pharmacological inhibition of its activity increased neurite outgrowth. In vivo study in mice provided evidence of the TRPA1 channel as a negative regulator in hippocampal functions; functional ablation of the TRPA1 channel in mice enhanced hippocampal functions, as evidenced by less anxiety-like behavior, and enhanced fear-related or spatial learning and memory, and novel location recognition as well as social interactions. However, the TRPA1 channel appears to be a prerequisite for motor function; functional loss of the TRPA1 channel in mice led to axonal bundle fragmentation, downregulation of myelin basic protein, and decreased mature oligodendrocyte population in the brain, for impaired motor function. The TRPA1 channel may play a crucial role in neuronal development and oligodendrocyte maturation and be a potential regulator in emotion, cognition, learning and memory, and social behavior.

  1. Effect of Vicarious Fear Learning on Children’s Heart Rate Responses and Attentional Bias for Novel Animals

    Science.gov (United States)

    2014-01-01

    Research with children has shown that vicarious learning can result in changes to 2 of Lang’s (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang’s final response system) and attentional bias. The study used Askew and Field’s (2007) vicarious learning procedure and demonstrated fear-related increases in children’s cognitive, behavioral, and physiological responses. Cognitive and behavioral changes were retested 1 week and 1 month later, and remained elevated. In addition, a visual search task demonstrated that fear-related vicarious learning creates an attentional bias for novel animals, which is moderated by increases in fear beliefs during learning. The findings demonstrate that vicarious learning leads to lasting changes in all 3 of Lang’s anxiety response systems and is sufficient to create attentional bias to threat in children. PMID:25151521

  2. Baseline Response Levels Are a Nuisance in Infant Contingency Learning

    Science.gov (United States)

    Millar, W. S.; Weir, Catherine

    2015-01-01

    The impact of differences in level of baseline responding on contingency learning in the first year was examined by considering the response acquisition of infants classified into baseline response quartiles. Whereas the three lower baseline groups showed the predicted increment in responding to a contingency, the highest baseline responders did…

  3. Loop-voltage tomography in tokamaks using transient synchrotron radiation

    International Nuclear Information System (INIS)

    Fisch, N.J.; Kritz, A.H.; Hunter Coll., New York, NY

    1989-07-01

    The loop voltage in tokamaks is particularly difficult to measure anywhere but at the plasma periphery. A brief, deliberate, perturbation of hot plasma electrons, however, produces a transient radiation response that is sensitive to this voltage. We investigate how such a radiation response can be used to diagnose the loop voltage. 24 refs., 6 figs

  4. Effect of vicarious fear learning on children's heart rate responses and attentional bias for novel animals

    OpenAIRE

    Reynolds, G; Field, AP; Askew, C

    2014-01-01

    Research with children has shown that vicarious learning can result in changes to 2 of Lang's (1968) 3 anxiety response systems: subjective report and behavioral avoidance. The current study extended this research by exploring the effect of vicarious learning on physiological responses (Lang's final response system) and attentional bias. The study used Askew and Field's (2007) vicarious learning procedure and demonstrated fear-related increases in children's cognitive, behavioral, and physiol...

  5. Influence of learning strategy on response time during complex value-based learning and choice.

    Directory of Open Access Journals (Sweden)

    Shiva Farashahi

    Full Text Available Measurements of response time (RT have long been used to infer neural processes underlying various cognitive functions such as working memory, attention, and decision making. However, it is currently unknown if RT is also informative about various stages of value-based choice, particularly how reward values are constructed. To investigate these questions, we analyzed the pattern of RT during a set of multi-dimensional learning and decision-making tasks that can prompt subjects to adopt different learning strategies. In our experiments, subjects could use reward feedback to directly learn reward values associated with possible choice options (object-based learning. Alternatively, they could learn reward values of options' features (e.g. color, shape and combine these values to estimate reward values for individual options (feature-based learning. We found that RT was slower when the difference between subjects' estimates of reward probabilities for the two alternative objects on a given trial was smaller. Moreover, RT was overall faster when the preceding trial was rewarded or when the previously selected object was present. These effects, however, were mediated by an interaction between these factors such that subjects were faster when the previously selected object was present rather than absent but only after unrewarded trials. Finally, RT reflected the learning strategy (i.e. object-based or feature-based approach adopted by the subject on a trial-by-trial basis, indicating an overall faster construction of reward value and/or value comparison during object-based learning. Altogether, these results demonstrate that the pattern of RT can be informative about how reward values are learned and constructed during complex value-based learning and decision making.

  6. Current interruption transients calculation

    CERN Document Server

    Peelo, David F

    2014-01-01

    Provides an original, detailed and practical description of current interruption transients, origins, and the circuits involved, and how they can be calculated Current Interruption Transients Calculationis a comprehensive resource for the understanding, calculation and analysis of the transient recovery voltages (TRVs) and related re-ignition or re-striking transients associated with fault current interruption and the switching of inductive and capacitive load currents in circuits. This book provides an original, detailed and practical description of current interruption transients, origins,

  7. ATWS: a reappraisal. Part III. Frequency of anticipated transients. Interim report

    International Nuclear Information System (INIS)

    Leverenz, F.L. Jr.; Koren, J.M.; Erdmann, R.C.; Lellouche, G.S.

    1978-07-01

    The document is Part III of the Institute study of the ATWS question. The frequencies of the various events which have led to a reactor scram are documented from the nuclear power plant records. Some of these events, in the absence of scram, could lead to undesirable system response and are the ''transients of significance'' which comprise the anticipated transients of the ATWS question

  8. Dynamic sensorimotor planning during long-term sequence learning: the role of variability, response chunking and planning errors.

    Science.gov (United States)

    Verstynen, Timothy; Phillips, Jeff; Braun, Emily; Workman, Brett; Schunn, Christian; Schneider, Walter

    2012-01-01

    Many everyday skills are learned by binding otherwise independent actions into a unified sequence of responses across days or weeks of practice. Here we looked at how the dynamics of action planning and response binding change across such long timescales. Subjects (N = 23) were trained on a bimanual version of the serial reaction time task (32-item sequence) for two weeks (10 days total). Response times and accuracy both showed improvement with time, but appeared to be learned at different rates. Changes in response speed across training were associated with dynamic changes in response time variability, with faster learners expanding their variability during the early training days and then contracting response variability late in training. Using a novel measure of response chunking, we found that individual responses became temporally correlated across trials and asymptoted to set sizes of approximately 7 bound responses at the end of the first week of training. Finally, we used a state-space model of the response planning process to look at how predictive (i.e., response anticipation) and error-corrective (i.e., post-error slowing) processes correlated with learning rates for speed, accuracy and chunking. This analysis yielded non-monotonic association patterns between the state-space model parameters and learning rates, suggesting that different parts of the response planning process are relevant at different stages of long-term learning. These findings highlight the dynamic modulation of response speed, variability, accuracy and chunking as multiple movements become bound together into a larger set of responses during sequence learning.

  9. SPICE modelling of the transient response of irradiated MOSFETs; Modelisation de la reponse transitoire de MOSFETs irradies avec SPICE

    Energy Technology Data Exchange (ETDEWEB)

    Pouget, V.; Lapuyade, H.; Lewis, D.; Deval, Y.; Fouillat, P. [Bordeaux-1 Univ., IXL, 33 - Talence (France); Sarger, L. [Bordeaux-1 Univ., CPMOH, 33 - Talence (France)

    1999-07-01

    A new SPICE model of irradiated MOSFET taking into account the real response of the 4 electrodes is proposed. The component that has been simulated is an NMOS transistor issued from the AMS BiCMOS 0.8 {mu}m technology. A comparison between SPICE-generated transients and PISCES device simulation demonstrates the accuracy benefits when used in complex electronic architectures. This model could be used when designing electronic circuits able to sustain hardening due to SEE (single event effect), it will be an efficient complement to the physical simulations.

  10. Assessing the implications of human land-use change for the transient climate response to cumulative carbon emissions

    International Nuclear Information System (INIS)

    Simmons, C T; Matthews, H D

    2016-01-01

    Recent research has shown evidence of a linear climate response to cumulative CO 2 emissions, which implies that the source, timing, and amount of emissions does not significantly influence the climate response per unit emission. Furthermore, these analyses have generally assumed that the climate response to land-use CO 2 emissions is equivalent to that of fossil fuels under the assumption that, once in the atmosphere, the radiative forcing induced by CO 2 is not sensitive to the emissions source. However, land-cover change also affects surface albedo and the strength of terrestrial carbon sinks, both of which have an additional climate effect. In this study, we use a coupled climate-carbon cycle model to assess the climate response to historical and future cumulative land-use CO 2 emissions, in order to compare it to the response to fossil fuel CO 2 . We find that when we isolate the CO 2 -induced (biogeochemical) temperature changes associated with land-use change, then the climate response to cumulative land-use emissions is equivalent to that of fossil fuel CO 2 . We show further that the globally-averaged albedo-induced biophysical cooling from land-use change is non-negligible and may be of comparable magnitude to the biogeochemical warming, with the result that the net climate response to land-use change is substantially different from a linear response to cumulative emissions. However, our new simulations suggest that the biophysical cooling from land-use change follows its own independent (negative) linear response to cumulative net land-use CO 2 emissions, which may provide a useful scaling factor for certain applications when evaluating the full transient climate response to emissions. (letter)

  11. Transient Response Improvement of Microgrids Exploiting the Inertia of a Doubly-Fed Induction Generator (DFIG

    Directory of Open Access Journals (Sweden)

    Christina N. Papadimitriou

    2010-06-01

    Full Text Available Storage devices are introduced in microgrids in order to secure their power quality, power regularity and offer ancillary services in a transient period. In the transition period of a low voltage microgrid, from the connected mode of operation to the islanded mode of operation, the power unbalance can be partly covered by the inertia energy of the existing power sources. This paper proposes fuzzy local controllers exploiting the inertia of a Wind Turbine (WT with a Doubly Fed Induction Generator (DFIG, if such a machine exists in the microgrid, in order to decrease the necessary storage devices and the drawbacks that arise. The proposed controllers are based in fuzzy logic due to the non linear and stochastic behavior of the system. Two cases are studied and compared during the transient period where the microgrid architecture and the DFIG controller differ. In the first case, the understudy microgrid includes a hybrid fuel cell system (FCS-battery system and a WT with a DFIGURE. The DFIG local controller in this case is also based in fuzzy logic and follows the classical optimum power absorption scenario for the WT. The transition of the microgrid from the connected mode of operation to the islanded mode is evaluated and, especially, the battery contribution is estimated. In the second case, the battery is eliminated. The fuzzy controller of the DFIG during the transition provides primary frequency control and local bus voltage support exploiting the WT inertia. The response of the system is estimated in both cases using MATLAB/Simulink software package.

  12. Nonassociative learning as gated neural integrator and differentiator in stimulus-response pathways

    Directory of Open Access Journals (Sweden)

    Young Daniel L

    2006-08-01

    Full Text Available Abstract Nonassociative learning is a basic neuroadaptive behavior exhibited across animal phyla and sensory modalities but its role in brain intelligence is unclear. Current literature on habituation and sensitization, the classic "dual process" of nonassociative learning, gives highly incongruous accounts between varying experimental paradigms. Here we propose a general theory of nonassociative learning featuring four base modes: habituation/primary sensitization in primary stimulus-response pathways, and desensitization/secondary sensitization in secondary stimulus-response pathways. Primary and secondary modes of nonassociative learning are distinguished by corresponding activity-dependent recall, or nonassociative gating, of neurotransmission memory. From the perspective of brain computation, nonassociative learning is a form of integral-differential calculus whereas nonassociative gating is a form of Boolean logic operator – both dynamically transforming the stimulus-response relationship. From the perspective of sensory integration, nonassociative gating provides temporal filtering whereas nonassociative learning affords low-pass, high-pass or band-pass/band-stop frequency filtering – effectively creating an intelligent sensory firewall that screens all stimuli for attention and resultant internal model adaptation and reaction. This unified framework ties together many salient characteristics of nonassociative learning and nonassociative gating and suggests a common kernel that correlates with a wide variety of sensorimotor integration behaviors such as central resetting and self-organization of sensory inputs, fail-safe sensorimotor compensation, integral-differential and gated modulation of sensorimotor feedbacks, alarm reaction, novelty detection and selective attention, as well as a variety of mental and neurological disorders such as sensorimotor instability, attention deficit hyperactivity, sensory defensiveness, autism

  13. Mechanical response of FFTF reference and P1 cladding tubes under transient heating

    International Nuclear Information System (INIS)

    Youngahl, C.A.; Ariman, T.; Lepacek, B.E.

    1977-01-01

    Burst tests of Type 316 stainless steel cladding tube samples subjected to increasing temperature and relatively constant internal pressure were conducted to assist in the pretest analysis of the P1 experiment performed in the Sodium Loop Safety Facility. This paper reports and analyzes the burst test results and those of subsequent transient heating work. The use of a modified extensometer in obtaining mechanical response data for stainless steel in the high temperature range is illustrated, some of such data is provided, and the potential of further experiments and analysis is indicated. Tubing of the same design as Fast Flux Test Facility (FFTF) cladding (20% cold worked, 0.230 in. OD, 15 mil wall) was tested as-received and after annealing or electrolytic thinning. P1 tubing (38% cold worked, 0.230 in. OD, 10 mil wall) was tested before and after aging under conditions anticipated in the P1 reactor experiment. The P1 cladding was designed to simulate FFTF tubing that had experienced irradiation embrittlement and attack by cesium oxide and sodium impurities

  14. Object Recognition in Clutter: Cortical Responses Depend on the Type of Learning

    Directory of Open Access Journals (Sweden)

    Jay eHegdé

    2012-06-01

    Full Text Available Theoretical studies suggest that the visual system uses prior knowledge of visual objects to recognize them in visual clutter, and posit that the strategies for recognizing objects in clutter may differ depending on whether or not the object was learned in clutter to begin with. We tested this hypothesis using functional magnetic resonance imaging (fMRI of human subjects. We trained subjects to recognize naturalistic, yet novel objects in strong or weak clutter. We then tested subjects’ recognition performance for both sets of objects in strong clutter. We found many brain regions that were differentially responsive to objects during object recognition depending on whether they were learned in strong or weak clutter. In particular, the responses of the left fusiform gyrus reliably reflected, on a trial-to-trial basis, subjects’ object recognition performance for objects learned in the presence of strong clutter. These results indicate that the visual system does not use a single, general-purpose mechanism to cope with clutter. Instead, there are two distinct spatial patterns of activation whose responses are attributable not to the visual context in which the objects were seen, but to the context in which the objects were learned.

  15. Sensitivity of transient synchrotron radiation to tokamak plasma parameters

    International Nuclear Information System (INIS)

    Fisch, N.J.; Kritz, A.H.

    1988-12-01

    Synchrotron radiation from a hot plasma can inform on certain plasma parameters. The dependence on plasma parameters is particularly sensitive for the transient radiation response to a brief, deliberate, perturbation of hot plasma electrons. We investigate how such a radiation response can be used to diagnose a variety of plasma parameters in a tokamak. 18 refs., 13 figs

  16. From feedback- to response-based performance monitoring in active and observational learning.

    Science.gov (United States)

    Bellebaum, Christian; Colosio, Marco

    2014-09-01

    Humans can adapt their behavior by learning from the consequences of their own actions or by observing others. Gradual active learning of action-outcome contingencies is accompanied by a shift from feedback- to response-based performance monitoring. This shift is reflected by complementary learning-related changes of two ACC-driven ERP components, the feedback-related negativity (FRN) and the error-related negativity (ERN), which have both been suggested to signal events "worse than expected," that is, a negative prediction error. Although recent research has identified comparable components for observed behavior and outcomes (observational ERN and FRN), it is as yet unknown, whether these components are similarly modulated by prediction errors and thus also reflect behavioral adaptation. In this study, two groups of 15 participants learned action-outcome contingencies either actively or by observation. In active learners, FRN amplitude for negative feedback decreased and ERN amplitude in response to erroneous actions increased with learning, whereas observational ERN and FRN in observational learners did not exhibit learning-related changes. Learning performance, assessed in test trials without feedback, was comparable between groups, as was the ERN following actively performed errors during test trials. In summary, the results show that action-outcome associations can be learned similarly well actively and by observation. The mechanisms involved appear to differ, with the FRN in active learning reflecting the integration of information about own actions and the accompanying outcomes.

  17. Transient ischemic attack presenting in an elderly patient with transient ophthalmic manifestations

    Directory of Open Access Journals (Sweden)

    Sparshi Jain

    2016-01-01

    Full Text Available Transient ischemic attack (TIA is a transient neurological deficit of cerebrovascular origin without infarction which may last only for a short period and can have varying presentations. We report a case of 58-year-old male with presenting features of sudden onset transient vertical diplopia and transient rotatory nystagmus which self-resolved within 12 h. Patient had no history of any systemic illness. On investigating, hematological investigations and neuroimaging could not explain these sudden and transient findings. A TIA could possibly explain these sudden and transient ocular findings in our patient. This case report aims to highlight the importance of TIA for ophthalmologists. We must not ignore these findings as these could be warning signs of an impending stroke which may or may not be detected on neuroimaging. Thus, early recognition, primary prevention strategies, and timely intervention are needed.

  18. Soil-structure interaction for transient loads due to safety relief valve discharges

    International Nuclear Information System (INIS)

    Tseng, W.S.; Tsai, N.C.

    1978-01-01

    Dynamic responses of BWR Mark II containment structures subjected to axisymmetric transient pressure loadings due to simultaneous safety relief valve discharges were investigated using finite element analysis, including the soil-structure interaction effect. To properly consider the soil-structure interaction effect, a simplified lumped parameter foundation model and axisymmetric finite element foundation model with viscous boundary impedance are used. Analytical results are presented to demonstrate the effectiveness of the simplified foundation model and to exhibit the dynamic response behavior of the structure as the transient loading frequency and the foundation rigidity vary. The impact of the dynamic structural response due to this type of loading on the equipment design is also discussed. (Auth.)

  19. PWR and BWR anticipated and abnormal plant transient research sponsored by the US Nuclear Regulatory Commission

    International Nuclear Information System (INIS)

    Beckner, W.D.; Sullivan, L.H.

    1984-01-01

    This chapter reviews the regulatory activities of the US NRC since the realization that anticipated transients with multiple failures (including operator actions) are the major contributors to risk from reactor operations and that the low probability design basis accidents (DBA) are relatively small contributors to risk. The Three Mile Island-2 accident demonstrated that anticipated transients, combined with multiple equipment and/or operator failures, can result in significant core damage. Topics considered include research in direct response to Three Mile Island-2, research in response to specific safety issues, and research to improve the overall understanding of transients (experimental facilities, computer codes). It is concluded that the US NRC has made significant progress in improving its ability to analyze and evaluate abnormal and anticipated transients

  20. Using Analytics to Nudge Student Responsibility for Learning

    Science.gov (United States)

    Fritz, John

    2017-01-01

    To scale student success, institutions may want to consider treating students more as partners, not just as customers or intervention recipients. One way to do so is sharing behavioral and academic feedback data that helps nudge students into taking responsibility for learning. The following chapter is drawn from the author's dissertation work…

  1. Impact of Load Behavior on Transient Stability and Power Transfer Limitations

    DEFF Research Database (Denmark)

    Gordon, Mark

    2009-01-01

    This paper presents utility based load modeling practices and explores the interaction between loads and the power system and the effect of the interaction on transient stability and power transfer limitations. The effect of load composition is investigated at major load centers together with the......This paper presents utility based load modeling practices and explores the interaction between loads and the power system and the effect of the interaction on transient stability and power transfer limitations. The effect of load composition is investigated at major load centers together...... with the impact on rotor angle excursions of large scale generators during the transient and post-transient period. Responses of multi-induction motor stalling are also considered for different fault clearances in the system. Findings of the investigations carried out on the Eastern Australian interconnected...

  2. Interactive and collaborative learning in the classroom at the medical school Automated response systems and team-based learning.

    Science.gov (United States)

    Nasr, Rihab; Antoun, Jumana; Sabra, Ramzi; Zgheib, Nathalie K

    2016-01-01

    There has been a pedagogic shift in higher education from the traditional teacher centered to the student centered approach in teaching, necessitating a change in the role of the teacher from a supplier of information to passive receptive students into a more facilitative role. Active learning activities are based on various learning theories such as self-directed learning, cooperative learning and adult learning. There exist many instructional activities that enhance active and collaborative learning. The aim of this manuscript is to describe two methods of interactive and collaborative learning in the classroom, automated response systems (ARS) and team-based learning (TBL), and to list some of their applications and advantages. The success of these innovative teaching and learning methods at a large scale depends on few elements, probably the most important of which is the support of the higher administration and leadership in addition to the availability of “champions” who are committed to lead the change.

  3. Transient analysis of multifailure conditions by using PWR plant simulator

    International Nuclear Information System (INIS)

    Morisaki, Hidetoshi; Yokobayashi, Masao.

    1984-11-01

    This report describes results of the analysis of abnormal transients caused by multifailures using a PWR plant simulator. The simulator is based on an existing 822MWe power plant with 3 loops, and designed to cover wide range of plant operation from cold shutdown to full power at the end of life. Various malfunctions to simulate abnormal conditions caused by equipment failures are provided. In this report, features of abnormal transients caused by concurrence of malfunctions are discussed. The abnormal conditions studied are leak of primary coolant, loss of charging and feedwater flows, and control systems failure. From the results, it was observed that transient responses caused by some of the malfunctions are almost same as the addition of behaviors caused by each single malfunction. Therefore, it can be said that kinds of malfunctions which are concurrent may be estimated from transient characteristics of each single malfunction. (author)

  4. Cataloguers May Tend to Have Learning Styles Different from Other Library Job Responsibilities

    Directory of Open Access Journals (Sweden)

    Eamon C. Tewell

    2016-04-01

    Full Text Available Objective – To determine whether relationships exist between academic librarians’ learning styles and their professional work responsibilities. Design – Self-selecting survey. Setting – Email listservs. Subjects – 1579 academic librarians. Methods – The authors used the Index of Learning Styles questionnaire, based on the Felder-Silverman Learning Styles model consisting of eight dimensions on four scales: Active/Reflective, Sensing/Intuitive, Visual/Verbal, and Sequential/Global. The multiple choice survey was distributed online to 23 email listservs for academic librarians in 2011, and to 14 additional listservs in 2013 targeting technical services librarians. 1579 responses were received in total, which were analyzed using ANOVA with a Tukey-Kramer post-hoc mean separation, and descriptively using observed frequencies. Main Results – In examining the relationship between positions and learning styles, the study revealed there to be five statistically significant p-values when the data were analyzed. Catalogers (n=145 were found to be more reflective learners compared to Administrative (n=321 and Instruction librarians (n=228 at the p = 0.009 level. Administrative, Instruction, and “Other” librarians were found to be more intuitive learners than Catalogers, who are more likely to be sensing learners, at the p = 0.0004 level. Digital librarians (n=40 are more likely to be visual learners and Catalogers more likely to be sequential learners when compared to several other librarian categories, at the p = 0.020 and p = 0.001 levels respectively. Conclusions – The authors concluded that there were some statistically significant differences between librarians’ learning styles scores according to job responsibilities. Catalogers were found to have different learning styles than other types of librarians for three out of four scales. Based on these findings, the authors indicate that further research into how librarians’ work

  5. Transient impedance changes in venous endothelial monolayers as a biological radiation dosimetry response

    Directory of Open Access Journals (Sweden)

    Erik Fossum Young

    2012-10-01

    Full Text Available In March of 2011, a magnitude 9.0 earthquake and subsequent 14 m-high tsunami caused major damage to the Fukushima Daiichi nuclear power plant in Japan.  While cancer incidence in the radiation-exposed population is a logical concern, the complex effects of radiation on the heart and cardiovascular system are also of interest.  Immediate and early vascular radiation effects could be exploited as a dosimetry modality.  To test whether non-coronary vasculature exhibited transient perturbation in barrier function, video microscopy studies and Electric Cell Substrate Impedance Sensing technology were used to probe very subtle changes in primary human vascular endothelium.  Human umbilical vein endothelial cell (HUVEC monolayers exhibit a transient, statistically significant decrease (P = 0.017 in monolayer resistance 3 h after irradiation with 5.0 Gy of g rays.  Radiation induced perturbations in HUVEC monolayer permeability are similar in magnitude and kinetics to those observed in coronary arterial endothelium.  Therefore, at least two types of vasculature respond to radiation on ECIS arrays with an early transient disruption in permeability.  The finding supports the use of early passage HUVECs for use in bioelectric dosimetry studies of vasculature and suggests that permeability of vessels could potentially serve as a biological dosimetry tool.

  6. Qualitative Student Responses to Service Learning with Veterans who are Homeless

    Directory of Open Access Journals (Sweden)

    Lindsay A. Phillips

    2012-04-01

    Full Text Available This article presents a description of a service learning activity in which students assisted veterans who are homeless. The article outlines how the event was organized, provides resources for implementation, discusses student response using evaluations from 15 students, and discusses considerations made in organizing such an event. KEYWORDSService Learning, Qualitative Evaluation, Homeless Veterans

  7. Transient analyzer

    International Nuclear Information System (INIS)

    Muir, M.D.

    1975-01-01

    The design and design philosophy of a high performance, extremely versatile transient analyzer is described. This sub-system was designed to be controlled through the data acquisition computer system which allows hands off operation. Thus it may be placed on the experiment side of the high voltage safety break between the experimental device and the control room. This analyzer provides control features which are extremely useful for data acquisition from PPPL diagnostics. These include dynamic sample rate changing, which may be intermixed with multiple post trigger operations with variable length blocks using normal, peak to peak or integrate modes. Included in the discussion are general remarks on the advantages of adding intelligence to transient analyzers, a detailed description of the characteristics of the PPPL transient analyzer, a description of the hardware, firmware, control language and operation of the PPPL transient analyzer, and general remarks on future trends in this type of instrumentation both at PPPL and in general

  8. Deformation modeling and the strain transient dip test

    International Nuclear Information System (INIS)

    Jones, W.B.; Rohde, R.W.; Swearengen, J.C.

    1980-01-01

    Recent efforts in material deformation modeling reveal a trend toward unifying creep and plasticity with a single rate-dependent formulation. While such models can describe actual material deformation, most require a number of different experiments to generate model parameter information. Recently, however, a new model has been proposed in which most of the requisite constants may be found by examining creep transients brought about through abrupt changes in creep stress (strain transient dip test). The critical measurement in this test is the absence of a resolvable creep rate after a stress drop. As a consequence, the result is extraordinarily sensitive to strain resolution as well as machine mechanical response. This paper presents the design of a machine in which these spurious effects have been minimized and discusses the nature of the strain transient dip test using the example of aluminum. It is concluded that the strain transient dip test is not useful as the primary test for verifying any micromechanical model of deformation. Nevertheless, if a model can be developed which is verifiable by other experimentts, data from a dip test machine may be used to generate model parameters

  9. Applying the principles of adult learning to the teaching of psychopharmacology: audience response systems.

    Science.gov (United States)

    Stahl, Stephen M; Davis, Richard L

    2009-08-01

    Medical presentations can be enhanced by systematically collecting audience feedback. This is readily accomplished with polling systems, called audience response systems. Several systems are now available that are small, inexpensive, and can be readily integrated into standard powerpoint presentations without the need for a technician. Use of audience response systems has several advantages. These include improving attentiveness, increasing learning, polling anonymously, tracking individual and group responses, gauging audience understanding, adding interactivity and fun, and evaluating both participant learning and instructor teaching. Tips for how to write questions for audience response systems are also included.

  10. Dynamical Networks Characterization of Geomagnetic Substorms and Transient Response to the Solar Wind State.

    Science.gov (United States)

    Chapman, S. C.; Dods, J.; Gjerloev, J. W.

    2017-12-01

    Observations of how the solar wind interacts with earth's magnetosphere, and its dynamical response, are increasingly becoming a data analytics challenge. Constellations of satellites observe the solar corona, the upstream solar wind and throughout earth's magnetosphere. These data are multipoint in space and extended in time, so in principle are ideal for study using dynamical networks to characterize the full time evolving spatial pattern. We focus here on analysis of data from the full set of 100+ auroral ground based magnetometer stations that have been collated by SuperMAG. Spatio-temporal patterns of correlation between the magnetometer time series can be used to form a dynamical network [1]. The properties of the network can then be captured by (time dependent) network parameters. This offers the possibility of characterizing detailed spatio-temporal pattern by a few parameters, so that many events can then be compared [2] with each other. Whilst networks are in widespread use in the data analytics of societal and commercial data, there are additional challenges in their application to physical timeseries. Determining whether two nodes (here, ground based magnetometer stations) are connected in a network (seeing the same dynamics) requires normalization w.r.t. the detailed sensitivities and dynamical responses of specific observing stations and seasonal conductivity variations and we have developed methods to achieve this dynamical normalization. The detailed properties of the network capture time dependent spatial correlation in the magnetometer responses and we will show how this can be used to infer a transient current system response to magnetospheric activity. [l] Dods et al, J. Geophys. Res 120, doi:10.1002/2015JA02 (2015). [2] Dods et al, J. Geophys. Res. 122, doi:10.1002/2016JA02 (2017).

  11. The transient creep of vapor deposited Ti-6Al-4V

    International Nuclear Information System (INIS)

    Warren, J.; Wadley, H.N.G.

    1996-01-01

    Titanium matrix composites can be synthesized by the consolidation of ceramic fibers (for example, alumina and silicon carbide monofilaments) coated with titanium alloy deposited on the fiber by physical vapor deposition (PVD). Consolidation involves deformation of the matrix coating by both transient and steady-state creep. In a recent paper the mechanisms responsible for steady-state creep in PVD Ti-6Al-4V, between 600 and 900 C, were determined. The analysis of the data first presented has been extended here to consider the transient creep behavior of the material and identify an analogous constitutive law for use in simulating the transient creep contribution to consolidation

  12. Heavy Ion Current Transients in SiGe HBTs

    Science.gov (United States)

    Pellish, Jonathan A.; Reed, Robert A.; Vizkelethy, Gyorgy; McMorrow, Dale; Ferlet-Cavrois, Veronique; Baggio, Jacques; Paillet, Philipe; Duhanel, Olivier; Phillips, Stanley D.; Sutton, Akil K.; hide

    2009-01-01

    Time-resolved ion beam induced charge reveals heavy ion response of IBM 5AM SiGe HBT: a) Position correlation[ b) Unique response for different bias schemes; c) Similarities to TPA pulsed-laser data. Heavy ion broad-beam transients provide more realistic device response: a) Feedback using microbeam data; b) Overcome issues of LET and ion range with microbeam. Both micro- and broad-beam data sets yield valuable input for TCAD simulations. Uncover detailed mechanisms for SiGe HBTs and other devices fabricated on lightly-doped substrates.

  13. Ark of Inquiry: Responsible Research and Innovation through Computer-Based Inquiry Learning

    NARCIS (Netherlands)

    Margus Pedaste; Leo Siiman; Bregje de Vries; Mirjam Burget; Tomi Jaakkola; Emanuele Bardone; Meelis Brikker; Mario Mäeots; Marianne Lind; Koen Veermans

    2015-01-01

    Ark of Inquiry is a learning platform that uses a computer-based inquiry learning approach to raise youth awareness to Responsible Research and Innovation (RRI). It is developed in the context of a large-scale European project (http://www.arkofinquiry.eu) and provides young European citizens

  14. Should we learn culture in chemistry classroom? Integration ethnochemistry in culturally responsive teaching

    Science.gov (United States)

    Rahmawati, Yuli; Ridwan, Achmad; Nurbaity

    2017-08-01

    The papers report the first year of two-year longitudinal study of ethnochemistry integration in culturally responsive teaching in chemistry classrooms. The teaching approach is focusing on exploring the culture and indigenous knowledge in Indonesia from chemistry perspectives. Ethnochemistry looks at the culture from chemistry perspectives integrated into culturally responsive teaching has developed students' cultural identity and students' engagement in chemistry learning. There are limited research and data in exploring Indonesia culture, which has around 300 ethics, from chemistry perspectives. Students come to the chemistry classrooms from a different background; however, their chemistry learning disconnected with their background which leads to students' disengagement in chemistry learning. Therefore this approach focused on students' engagement within their differences. This research was conducted with year 10 and 11 from four classrooms in two secondary schools through qualitative methodology with observation, interviews, and reflective journals as data collection. The results showed that the integration of ethnochemistry in culturally responsive teaching approach can be implemented by involving 5 principles which are content integration, facilitating knowledge construction, prejudice reduction, social justice, and academic development. The culturally responsive teaching has engaged students in their chemistry learning and developed their cultural identity and soft skills. Students found that the learning experiences has helped to develop their chemistry knowledge and understand the culture from chemistry perspectives. The students developed the ability to work together, responsibility, curiosity, social awareness, creativity, empathy communication, and self-confidence which categorized into collaboration skills, student engagement, social and cultural awareness, and high order thinking skills. The ethnochemistry has helped them to develop the critical self

  15. Auditory Magnetoencephalographic Frequency-Tagged Responses Mirror the Ongoing Segmentation Processes Underlying Statistical Learning.

    Science.gov (United States)

    Farthouat, Juliane; Franco, Ana; Mary, Alison; Delpouve, Julie; Wens, Vincent; Op de Beeck, Marc; De Tiège, Xavier; Peigneux, Philippe

    2017-03-01

    Humans are highly sensitive to statistical regularities in their environment. This phenomenon, usually referred as statistical learning, is most often assessed using post-learning behavioural measures that are limited by a lack of sensibility and do not monitor the temporal dynamics of learning. In the present study, we used magnetoencephalographic frequency-tagged responses to investigate the neural sources and temporal development of the ongoing brain activity that supports the detection of regularities embedded in auditory streams. Participants passively listened to statistical streams in which tones were grouped as triplets, and to random streams in which tones were randomly presented. Results show that during exposure to statistical (vs. random) streams, tritone frequency-related responses reflecting the learning of regularities embedded in the stream increased in the left supplementary motor area and left posterior superior temporal sulcus (pSTS), whereas tone frequency-related responses decreased in the right angular gyrus and right pSTS. Tritone frequency-related responses rapidly developed to reach significance after 3 min of exposure. These results suggest that the incidental extraction of novel regularities is subtended by a gradual shift from rhythmic activity reflecting individual tone succession toward rhythmic activity synchronised with triplet presentation, and that these rhythmic processes are subtended by distinct neural sources.

  16. Transient drainage summary report

    International Nuclear Information System (INIS)

    1996-09-01

    This report summarizes the history of transient drainage issues on the Uranium Mill Tailings Remedial Action (UMTRA) Project. It defines and describes the UMTRA Project disposal cell transient drainage process and chronicles UMTRA Project treatment of the transient drainage phenomenon. Section 4.0 includes a conceptual cross section of each UMTRA Project disposal site and summarizes design and construction information, the ground water protection strategy, and the potential for transient drainage

  17. TRANSIENT ELECTRONICS CATEGORIZATION

    Science.gov (United States)

    2017-08-24

    AFRL-RY-WP-TR-2017-0169 TRANSIENT ELECTRONICS CATEGORIZATION Dr. Burhan Bayraktaroglu Devices for Sensing Branch Aerospace Components & Subsystems...SUBTITLE TRANSIENT ELECTRONICS CATEGORIZATION 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A 6. AUTHOR(S) Dr. Burhan...88ABW-2017-3747, Clearance Date 31 July 2017. Paper contains color. 14. ABSTRACT Transient electronics is an emerging technology area that lacks proper

  18. Effective image differencing with convolutional neural networks for real-time transient hunting

    Science.gov (United States)

    Sedaghat, Nima; Mahabal, Ashish

    2018-06-01

    Large sky surveys are increasingly relying on image subtraction pipelines for real-time (and archival) transient detection. In this process one has to contend with varying point-spread function (PSF) and small brightness variations in many sources, as well as artefacts resulting from saturated stars and, in general, matching errors. Very often the differencing is done with a reference image that is deeper than individual images and the attendant difference in noise characteristics can also lead to artefacts. We present here a deep-learning approach to transient detection that encapsulates all the steps of a traditional image-subtraction pipeline - image registration, background subtraction, noise removal, PSF matching and subtraction - in a single real-time convolutional network. Once trained, the method works lightening-fast and, given that it performs multiple steps in one go, the time saved and false positives eliminated for multi-CCD surveys like Zwicky Transient Facility and Large Synoptic Survey Telescope will be immense, as millions of subtractions will be needed per night.

  19. Evaluating transient performance of servo mechanisms by analysing stator current of PMSM

    Science.gov (United States)

    Zhang, Qing; Tan, Luyao; Xu, Guanghua

    2018-02-01

    Smooth running and rapid response are the desired performance goals for the transient motions of servo mechanisms. Because of the uncertain and unobservable transient behaviour of servo mechanisms, it is difficult to evaluate their transient performance. Under the effects of electromechanical coupling, the stator current signals of a permanent-magnet synchronous motor (PMSM) potentially contain the performance information regarding servo mechanisms in use. In this paper, a novel method based on analysing the stator current of the PMSM is proposed for quantifying the transient performance. First, a vector control model is constructed to simulate the stator current behaviour in the transient processes of consecutive speed changes, consecutive load changes, and intermittent start-stops. It is discovered that the amplitude and frequency of the stator current are modulated by the transient load torque and motor speed, respectively. The stator currents under different performance conditions are also simulated and compared. Then, the stator current is processed using a local means decomposition (LMD) algorithm to extract the instantaneous amplitude and instantaneous frequency. The sample entropy of the instantaneous amplitude, which reflects the complexity of the load torque variation, is calculated as a performance indicator of smooth running. The peak-to-peak value of the instantaneous frequency, which defines the range of the motor speed variation, is set as a performance indicator of rapid response. The proposed method is applied to both simulated data in an intermittent start-stops process and experimental data measured for a batch of servo turrets for turning lathes. The results show that the performance evaluations agree with the actual performance.

  20. The Analysis of Interactivity in a Teaching and Learning Sequence of Rugby: The Transfer of Control and Learning Responsibility

    Science.gov (United States)

    Llobet-Martí, Bernat; López-Ros, Víctor; Vila, Ignasi

    2018-01-01

    Background: The social constructivist perspective emphasises that learning is a process of self-construction of knowledge in a social context. Game-centred approaches, such as teaching games for understanding, have been used in accordance with this perspective. The process of transferring learning responsibility takes place when the learner is…

  1. Analysis of pressure wave transients and seismic response in LMFBR piping systems using the SHAPS code

    International Nuclear Information System (INIS)

    Zeuch, W.R.; Wang, C.Y.

    1985-01-01

    This paper presents some of the current capabilities of the three-dimensional piping code SHAPS and demonstrates their usefulness in handling analyses encountered in typical LMFBR studies. Several examples demonstrate the utility of the SHAPS code for problems involving fluid-structure interactions and seismic-related events occurring in three-dimensional piping networks. Results of two studies of pressure wave propagation demonstrate the dynamic coupling of pipes and elbows producing global motion and rigorous treatment of physical quantities such as changes in density, pressure, and strain energy. Results of the seismic analysis demonstrate the capability of SHAPS to handle dynamic structural response within a piping network over an extended transient period of several seconds. Variation in dominant stress frequencies and global translational frequencies were easily handled with the code. 4 refs., 10 figs

  2. Is the auditory evoked P2 response a biomarker of learning?

    Directory of Open Access Journals (Sweden)

    Kelly eTremblay

    2014-02-01

    Full Text Available Even though auditory training exercises for humans have been shown to improve certain perceptual skills of individuals with and without hearing loss, there is a lack of knowledge pertaining to which aspects of training are responsible for the perceptual gains, and which aspects of perception are changed. To better define how auditory training impacts brain and behavior, electroencephalography and magnetoencephalography have been used to determine the time course and coincidence of cortical modulations associated with different types of training. Here we focus on P1-N1-P2 auditory evoked responses (AEP, as there are consistent reports of gains in P2 amplitude following various types of auditory training experiences; including music and speech-sound training. The purpose of this experiment was to determine if the auditory evoked P2 response is a biomarker of learning. To do this, we taught native English speakers to identify a new pre-voiced temporal cue that is not used phonemically in the English language so that coinciding changes in evoked neural activity could be characterized. To differentiate possible effects of repeated stimulus exposure and a button-pushing task from learning itself, we examined modulations in brain activity in a group of participants who learned to identify the pre-voicing contrast and compared it to participants, matched in time, and stimulus exposure, that did not. The main finding was that the amplitude of the P2 auditory evoked response increased across repeated EEG sessions for all groups, regardless of any change in perceptual performance. What’s more, these effects were retained for months. Changes in P2 amplitude were attributed to changes in neural activity associated with the acquisition process and not the learned outcome itself. A further finding was the expression of a late negativity (LN wave 600-900 ms post-stimulus onset, post-training, exclusively for the group that learned to identify the pre

  3. Simulation and analysis of transient over voltages due to capacitor banks switching

    International Nuclear Information System (INIS)

    Jadid, Sh.; Yazdanpanah, D.

    2002-01-01

    The switching of any capacitor bank produces over voltages. Transient overvoltage will always occur in the switching device, the switching of shunt capacitor bank has become the most common source of transient voltage on power systems. Transient over voltages due to switching the capacitor bands hurt not only to the capacitor banks, but also to other equipment, such as circuit breakers and transformers. Several methods are available for reducing energising transients. These devices include pre-insertion resistors, pre-insertion inductors,synchronous closing, and MOV arresters. However, not all are practical or economical. The other important problem is existence of capacitor banks in presence of harmonics.Capacitors do not produce harmonics;however,the addition of capacitors to the electrical system will change the frequency response characteristics of the system will change the frequency response characteristics of the system, and in some cases can result in magnification of the voltage and current distortion in the system. In other word in presence of harmonic-producing loads,the capacitors used for power factor correction,may cause parallel resonance with the system inductance, so they increase the total harmonic distortion of voltage and current waveforms

  4. Analysis of the transient response and durability characteristics of a proton exchange membrane fuel cell with different micro-porous layer penetration thicknesses

    International Nuclear Information System (INIS)

    Cho, Junhyun; Park, Jaeman; Oh, Hwanyeong; Min, Kyoungdoug; Lee, Eunsook; Jyoung, Jy-Young

    2013-01-01

    Highlights: • The GDL which has a large MPL penetration showed a better transient response. • The transient response of the PEMFC was affected by the water balance of the GDL. • A large MPL penetration balanced the capillary pressure gradient through the GDL. • The carbon corrosion induced loss of the MPL penetration region. - Abstract: The optimal design of the gas diffusion layer (GDL) of proton exchange membrane fuel cells is crucial because it directly determines the mass transport mechanism of the reactants and products. In this study, the micro-porous layer (MPL) penetration thickness, which affects the pore size profile through the GDL, is varied as the design parameter of the GDL. The cell performance is investigated under various humidity conditions, and the water permeability characteristics are studied. In addition, the accelerated carbon corrosion stress test is conducted to determine the effect of MPL penetration on GDL degradation. GDLs with large MPL penetration thickness show better performance in the high-current–density region due to the enhanced management of water resulting from a balanced capillary pressure gradient. However, the loss of penetrated MPL parts is observed due to the low binding force between the MPL and the GDL substrate

  5. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  6. The impact of transient combination antiretroviral treatment in early HIV infection on viral suppression and immunologic response in later treatment.

    Science.gov (United States)

    Pantazis, Nikos; Touloumi, Giota; Meyer, Laurence; Olson, Ashley; Costagliola, Dominique; Kelleher, Anthony D; Lutsar, Irja; Chaix, Marie-Laure; Fisher, Martin; Moreno, Santiago; Porter, Kholoud

    2016-03-27

    Effects of transient combination antiretroviral treatment (cART) initiated during early HIV infection (EHI) remain unclear. We investigate whether this intervention affects viral suppression and CD4 cell count increase following its reinitiation in chronic infection (CHI). Longitudinal observational study. We identified adult patients from Concerted Action of Seroconversion to AIDS and Death in Europe who seroconverted after 1/1/2000, had a 12 months or less HIV test interval and initiated cART from naive. We classified individuals as 'pretreated in EHI' if treated within 6 months of seroconversion, interrupted for at least 12 weeks, and reinitiated during CHI. Statistical analysis was performed using survival analysis methods and mixed models. Pretreated and initiated in CHI groups comprised 202 and 4263 individuals, with median follow-up after CHI treatment 4.5 and 3 years, respectively. Both groups had similar virologic response and relapse rates (P = 0.585 and P = 0.206) but pretreated individuals restarted treatment with higher baseline CD4 cell count (∼80 cells/μl; P treatment (re)initiation. Assuming common baseline CD4 cell count, differences in CD4 cell count slopes were nonsignificant. Immunovirologic response to CHI treatment was not associated with timing or duration of the transient treatment. Although treatment interruptions are not recommended, stopping cART initiated in EHI does not seem to reduce the chance of a successful outcome of treatment in CHI.

  7. Student Response to Remote-Online Case-Based Learning: A Qualitative Study.

    Science.gov (United States)

    Nicklen, Peter; Keating, Jennifer L; Maloney, Stephen

    2016-03-22

    Case-based learning (CBL) typically involves face-to-face interaction in small collaborative groups with a focus on self-directed study. To our knowledge, no published studies report an evaluation of Web conferencing in CBL. The primary aim of this study was to explore student perceptions and attitudes in response to a remote-online case-based learning (RO-CBL) experience. This study took place over a 2-week period in 2013 at Monash University, Victoria, Australia. A third year cohort (n=73) of physiotherapy students was invited to participate. Students were required to participate in 2 training sessions, followed by RO-CBL across 2 sessions. The primary outcome of interest was the student feedback on the quality of the learning experience during RO-CBL participation. This was explored with a focus group and a survey. Most students (68/73) completed the postintervention survey (nonparticipation rate 8%). RO-CBL was generally well received by participants, with 59% (40/68) of participates stating that they'd like RO-CBL to be used in the future and 78% (53/68) of participants believing they could meet the CBL's learning objectives via RO-CBL. The 4 key themes relevant to student response to RO-CBL that emerged from the focus groups and open-ended questions on the postintervention survey were how RO-CBL compared to expectations, key benefits of RO-CBL including flexibility and time and cost savings, communication challenges in the online environment compared to face-to-face, and implications of moving to an online platform. Web conferencing may be a suitable medium for students to participate in CBL. Participants were satisfied with the learning activity and felt they could meet the CBL's learning objectives. Further study should evaluate Web conferencing CBL across an entire semester in regard to student satisfaction, perceived depth of learning, and learning outcomes.

  8. PSH Transient Simulation Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, Eduard [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-12-21

    PSH Transient Simulation Modeling presentation from the WPTO FY14 - FY16 Peer Review. Transient effects are an important consideration when designing a PSH system, yet numerical techniques for hydraulic transient analysis still need improvements for adjustable-speed (AS) reversible pump-turbine applications.

  9. Transient analysis for a system with a tilted disc check valve

    International Nuclear Information System (INIS)

    Jeung, Jaesik; Lee, Kyukwang; Cho, Daegwan

    2014-01-01

    Check valves are used to prevent reverse flow conditions in a variety of systems in nuclear power plants. When a check valve is closed by a reverse flow, the transient load can jeopardize the structural integrity on the piping system and its supports. It may also damage intended function of the in-line components even though the severity of the load differs and depends strongly on types of the check valves. To incorporate the transient load in the piping system, it is very important to properly predict the system response to transients such as a check valve closure accompanied by pump trip and to evaluate the system transient. The one-dimensional transient simulation codes such as the RELAP5/MOD3.3 and TRACE were used. There has not been a single model that integrates the two codes to handle the behavior of a tilted disc check valve, which is designed to mitigate check valve slams by shorting the travel of the disc. In this paper a model is presented to predict the dynamic motion of a tilted disc check valve in the transient simulation using the RELAP5/MOD3.3 code and the model is incorporated in a system transient analysis using control variables of the code. In addition, transient analysis for Essential Service Water (ESW) system is performed using the proposed model and the associated load is evaluated for the system. (author)

  10. Inescapable Stress Changes Walking Behavior in Flies - Learned Helplessness Revisited.

    Science.gov (United States)

    Batsching, Sophie; Wolf, Reinhard; Heisenberg, Martin

    2016-01-01

    Like other animals flies develop a state of learned helplessness in response to unescapable aversive events. To show this, two flies, one 'master', one 'yoked', are each confined to a dark, small chamber and exposed to the same sequence of mild electric shocks. Both receive these shocks when the master fly stops walking for more than a second. Behavior in the two animals is differently affected by the shocks. Yoked flies are transiently impaired in place learning and take longer than master flies to exit from the chamber towards light. After the treatment they walk more slowly and take fewer and shorter walking bouts. The low activity is attributed to the fly's experience that its escape response, an innate behavior to terminate the electric shocks, does not help anymore. Earlier studies using heat pulses instead of electric shocks had shown similar effects. This parallel supports the interpretation that it is the uncontrollability that induces the state.

  11. Inescapable Stress Changes Walking Behavior in Flies - Learned Helplessness Revisited

    Science.gov (United States)

    Batsching, Sophie; Wolf, Reinhard; Heisenberg, Martin

    2016-01-01

    Like other animals flies develop a state of learned helplessness in response to unescapable aversive events. To show this, two flies, one 'master', one 'yoked', are each confined to a dark, small chamber and exposed to the same sequence of mild electric shocks. Both receive these shocks when the master fly stops walking for more than a second. Behavior in the two animals is differently affected by the shocks. Yoked flies are transiently impaired in place learning and take longer than master flies to exit from the chamber towards light. After the treatment they walk more slowly and take fewer and shorter walking bouts. The low activity is attributed to the fly's experience that its escape response, an innate behavior to terminate the electric shocks, does not help anymore. Earlier studies using heat pulses instead of electric shocks had shown similar effects. This parallel supports the interpretation that it is the uncontrollability that induces the state. PMID:27875580

  12. Inescapable Stress Changes Walking Behavior in Flies - Learned Helplessness Revisited.

    Directory of Open Access Journals (Sweden)

    Sophie Batsching

    Full Text Available Like other animals flies develop a state of learned helplessness in response to unescapable aversive events. To show this, two flies, one 'master', one 'yoked', are each confined to a dark, small chamber and exposed to the same sequence of mild electric shocks. Both receive these shocks when the master fly stops walking for more than a second. Behavior in the two animals is differently affected by the shocks. Yoked flies are transiently impaired in place learning and take longer than master flies to exit from the chamber towards light. After the treatment they walk more slowly and take fewer and shorter walking bouts. The low activity is attributed to the fly's experience that its escape response, an innate behavior to terminate the electric shocks, does not help anymore. Earlier studies using heat pulses instead of electric shocks had shown similar effects. This parallel supports the interpretation that it is the uncontrollability that induces the state.

  13. Multilevel linear modelling of the response-contingent learning of young children with significant developmental delays.

    Science.gov (United States)

    Raab, Melinda; Dunst, Carl J; Hamby, Deborah W

    2018-02-27

    The purpose of the study was to isolate the sources of variations in the rates of response-contingent learning among young children with multiple disabilities and significant developmental delays randomly assigned to contrasting types of early childhood intervention. Multilevel, hierarchical linear growth curve modelling was used to analyze four different measures of child response-contingent learning where repeated child learning measures were nested within individual children (Level-1), children were nested within practitioners (Level-2), and practitioners were nested within the contrasting types of intervention (Level-3). Findings showed that sources of variations in rates of child response-contingent learning were associated almost entirely with type of intervention after the variance associated with differences in practitioners nested within groups were accounted for. Rates of child learning were greater among children whose existing behaviour were used as the building blocks for promoting child competence (asset-based practices) compared to children for whom the focus of intervention was promoting child acquisition of missing skills (needs-based practices). The methods of analysis illustrate a practical approach to clustered data analysis and the presentation of results in ways that highlight sources of variations in the rates of response-contingent learning among young children with multiple developmental disabilities and significant developmental delays. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. An overview of optimization of structures subjected to transient loads

    International Nuclear Information System (INIS)

    Kang, Byung Soo; Park, Gyung Jin

    2005-01-01

    Various aspects of structural optimization techniques under transient loads are extensively reviewed. The main themes of the paper are treatment of time dependent constraints, calculation of design sensitivity, and approximation. Each subject is reviewed with the corresponding papers that have been published since 1970s. The treatment of time dependent constraints in both the direct method and the transformation method is discussed. Two ways of calculating design sensitivity of a structure under transient loads are discussed-direct differentiation method and adjoint variable method. The approximation concept mainly focuses on response surface method in crashworthiness and local approximation with the intermediate variable. Especially, as an approximated optimization technique, equivalent static load method which takes advantage of the well-established static response optimization technique is introduced. And as an application area of dynamic response optimization technique, the structural optimization in flexible multibody dynamic system is reviewed in the viewpoint of the above three themes

  15. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Directory of Open Access Journals (Sweden)

    Jeffrey Tuck

    2013-12-01

    Full Text Available Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the

  16. Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines

    Science.gov (United States)

    Tuck, Jeffrey; Lee, Pedro

    2013-01-01

    Analysis of transient fluid pressure signals has been investigated as an alternative method of fault detection in pipeline systems and has shown promise in both laboratory and field trials. The advantage of the method is that it can potentially provide a fast and cost effective means of locating faults such as leaks, blockages and pipeline wall degradation within a pipeline while the system remains fully operational. The only requirement is that high speed pressure sensors are placed in contact with the fluid. Further development of the method requires detailed numerical models and enhanced understanding of transient flow within a pipeline where variations in pipeline condition and geometry occur. One such variation commonly encountered is the degradation or thinning of pipe walls, which can increase the susceptible of a pipeline to leak development. This paper aims to improve transient-based fault detection methods by investigating how changes in pipe wall thickness will affect the transient behaviour of a system; this is done through the analysis of laboratory experiments. The laboratory experiments are carried out on a stainless steel pipeline of constant outside diameter, into which a pipe section of variable wall thickness is inserted. In order to detect the location and severity of these changes in wall conditions within the laboratory system an inverse transient analysis procedure is employed which considers independent variations in wavespeed and diameter. Inverse transient analyses are carried out using a genetic algorithm optimisation routine to match the response from a one-dimensional method of characteristics transient model to the experimental time domain pressure responses. The accuracy of the detection technique is evaluated and benefits associated with various simplifying assumptions and simulation run times are investigated. It is found that for the case investigated, changes in the wavespeed and nominal diameter of the pipeline are both important

  17. Modeling and analysis of thermal-hydraulic response of uranium-aluminum reactor fuel plates under transient heatup conditions

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Valenti, S.; Kim, S.H.; Georgevich, V. [Oak Ridge National Lab., TN (United States)] [and others

    1995-09-01

    The purpose of this paper is to describe the analysis performed to predict the thermal behavior of fuel miniplates under rapid transient heatup conditions. The possibility of explosive boiling was considered, and it was concluded that the heating rates are not large enough for explosive boiling to occur. However, transient boiling effects were pronounced. Because of the complexity of transient pool boiling and the unavailability of experimental data for the situations studied, an approximation was made that predicted the data very well within the uncertainties present. If pool boiling from the miniplates had been assumed to be steady during the heating pulse, the experimental data would have been greatly overestimated. This fact demonstrates the importance of considering the transient nature of heat transfer in the analysis of reactivity excursion accidents. An additional contribution of the present work is that it provided data on highly subcooled steady nulceate boiling from the cooling portion of the thermocouple traces.

  18. Transient river response, captured by channel steepness and its concavity

    Science.gov (United States)

    Vanacker, Veerle; von Blanckenburg, Friedhelm; Govers, Gerard; Molina, Armando; Campforts, Benjamin; Kubik, Peter W.

    2015-01-01

    Mountain rivers draining tropical regions are known to be great conveyor belts carrying efficiently more than half of the global sediment flux to the oceans. Many tropical mountain areas are located in tectonically active belts where the hillslope and stream channel morphology are rapidly evolving in response to changes in base level. Here, we report basin-wide denudation rates for an east-west transect through the tropical Andes. Hillslope and channel morphology vary systematically from east to west, reflecting the transition from high relief, strongly dissected topography in the escarpment zones into relatively low relief topography in the inter-Andean valley. The spatial pattern of differential denudation rates reflects the transient adjustment of the landscape to rapid river incision following tectonic uplift and river diversion. In the inter-Andean valley, upstream of the wave of incision, slopes and river channels display a relatively smooth, concave-up morphology and denudation rates (time scale of 104-105 a) are consistently low (3 to 200 mm/ka). In contrast, slopes and river channels of rejuvenated basins draining the eastern cordillera are steep to very steep; and the studied drainage basins show a wide range of denudation rate values (60 to 400 mm/ka) that increase systematically with increasing basin mean slope gradient, channel steepness, and channel convexity. Drainage basins that are characterised by strong convexities in their river longitudinal profiles systematically have higher denudation rates. As such, this is one of the first studies that provides field-based evidence of a correlation between channel concavity and basin mean denudation rates, consistent with process-based fluvial incision models.

  19. Low temperature transient response and electroluminescence characteristics of OLEDs based on Alq3

    Science.gov (United States)

    Yuan, Chao; Guan, Min; Zhang, Yang; Li, Yiyang; Liu, Shuangjie; Zeng, Yiping

    2017-08-01

    In this work, the organic light-emitting diodes (OLEDs) based on Alq3 are fabricated. In order to make clear the transport mechanism of carriers in organic light-emitting devices at low temperature, detailed electroluminescence transient response and the current-voltage-luminescence (I-V-L) characteristics under different temperatures in those OLEDs are investigated. It founds that the acceleration of brightness increases with increasing temperature is maximum when the temperature is 200 K and it is mainly affected by the electron transport layer (Alq3). The MoO3 injection layer and the electroluminescent layer have great influence on the delay time when the temperature is 200 K. Once the temperature is greater than 250 K, the delay time is mainly affected by the MoO3 injection layer. On the contrary, the fall time is mainly affected by the electroluminescent material. The Vf is the average growth rate of fall time when the temperature increases 1 K which represents the accumulation rate of carriers. The difference between Vf caused by the MoO3 injection layer is 0.52 us/K and caused by the electroluminescent material Ir(ppy)3 is 0.73 us/K.

  20. Nonlinear transient responses of beams and rings to impulse loading or fragment impact

    International Nuclear Information System (INIS)

    Witmer, E.A.; Stagliano, T.R.; Rodal, J.J.A.

    1977-01-01

    Nuclear power plant protective structures may be subjected to various external missiles such as aircraft and tornado-generated missiles: telephone poles, planks, pipes, rods, automobiles, and other blown vehicles. Also, 'internally-generated missiles' such as fragments from powerplant rotors and aircraft engine rotors may impact protective structures. The present paper is concerned with a very limited part of the cited fragment threat; namely, fragments from high speed rotating machinery such as (1) aircraft engine rotors and (2) stationary power plant turbine rotors. Further, it is assumed that the structures intended to contain or control these fragments consist of initially-isotopic elastic-plastic metals. Certain potential containment/control (C/C) structures behave in a planar (or two-dimensional) fashion while other fragment-attacked C/C structures will undergo general three-dimensional deformations. Predictions for only the former category of fragment-attacked structures are discussed in the present paper. Pertinent experimental data discussed on fragment-attacked structures include (a) steel-sphere impact data involving beam targets and (b) engine rotor fragment impact against a steel containment ring. In all of these cases large-deflection, elastic-plastic transient structural responses occur. (Auth.)

  1. The Impact of Learning Culture on Worker Response to New Technology

    Science.gov (United States)

    Reardon, Robert F.

    2010-01-01

    Purpose: The aim of this paper is to provide a framework to measure the response of blue-collar workers to new technology in manufacturing and to establish the relationship between learning culture and that response. Design/methodology/approach: The data were collected with a survey questionnaire from 12 manufacturing sites that were implementing…

  2. Facilitating Student Engagement: Social Responsibility and Freshmen Learning Communities

    Science.gov (United States)

    Kingston, Lindsey N.; MacCartney, Danielle; Miller, Andrea

    2014-01-01

    Human rights education is advanced as a method for promoting social responsibility, with an emphasis on promoting ideals of "global citizenship" among undergraduate students. At the same time, the practice of learning communities is widespread on college campuses for retaining freshmen and promoting student success. However, there is…

  3. Effects of Different Student Response Modes on Science Learning

    Science.gov (United States)

    Kho, Lee Sze; Chen, Chwen Jen

    2017-01-01

    Student response systems (SRSs) are wireless answering devices that enable students to provide simple real-time feedback to instructors. This study aims to evaluate the effects of different SRS interaction modes on elementary school students' science learning. Three interaction modes which include SRS Individual, SRS Collaborative, and Classroom…

  4. Modeling of the transient mobility in disordered organic semiconductors

    NARCIS (Netherlands)

    Germs, W.C.; Van der Holst, J.M.M.; Van Mensfoort, S.L.M.; Bobbert, P.A.; Coehoorn, R.

    2011-01-01

    In non-steady-state experiments, the electrical response of devicesbased on disordered organic semiconductors often shows a large transient contribution due to relaxation of the out-of-equilibrium charge-carrier distribution. We have developed a model describing this process, based only on the

  5. Analytic models for fuel pin transient performance

    International Nuclear Information System (INIS)

    Bard, F.E.; Fox, G.L.; Washburn, D.F.; Hanson, J.E.

    1976-09-01

    HEDL's ability to analyze various mechanisms that operate within a fuel pin has progressed substantially through development of codes such as PECTCLAD, which solves cladding response, and DSTRESS, which solves fuel response. The PECTCLAD results show good correlation with a variety of mechanical tests on cladding material and also demonstrate the significance of cladding strength when applying the life fraction rule. The DSTRESS results have shown that fuel deforms sufficiently during overpower transient tests that available volumes are filled, whether in the form of a central cavity or start-up cracks

  6. Occurrence and predictors of persistent impaired glucose tolerance after acute ischemic stroke or transient ischemic attack

    NARCIS (Netherlands)

    S. Fonville (Susanne); H.M. den Hertog (Heleen); A.A.M. Zandbergen (Adrienne); P.J. Koudstaal (Peter Jan); H.F. Lingsma (Hester)

    2014-01-01

    textabstractBackground Impaired glucose tolerance is often present in patients with a transient ischemic attack (TIA) or ischemic stroke and doubles the risk of recurrent stroke. This impaired glucose tolerance can be transient, reflecting an acute stress response, or persistent, representing

  7. RETRAN experience with BWR transients at Yankee Atomic Electric Company

    International Nuclear Information System (INIS)

    Ansari, A.A.F.; Cronin, J.T.; Slifer, B.C.

    1981-01-01

    Yankee Atomic Electric Company is actively involved in the development of licensing methods for BWR's. The computer code chosen for analyzing system response under transient conditions is RETRAN. This paper describes the RETRAN model developed for Vermont Yankee, and the results of the RETRAN checkout and qualification that has been achieved at YAEC through comparison of RETRAN predictions to the startup test results performed at the plant as part of the 100% power startup test program. In addition, abnormal operational transients typically analyzed for licensing are also presented

  8. Incorporating fan control into air-conditioning systems to improve energy efficiency and transient response

    International Nuclear Information System (INIS)

    Yeh, T.-J.; Chen, Yun-Jih; Hwang, Wei-Yang; Lin, Jin-Long

    2009-01-01

    Modern air-conditioners frequently incorporate variable-speed compressors and variable-opening expansion valves with feedback control to improve performance and power efficiency. Because making the fan speeds adjustable adds flexibility to the control design and thus can lead to further improvements in performance and efficiency, this paper proposes two control algorithms, respectively, incorporating the outdoor fan and the indoor fan as the additional control inputs for air-conditioning systems. Both of the control algorithms are designed based on a low-order, linear model obtained from system identification. The first algorithm, which modulates the outdoor fan speed, can reduce the steady state power consumption if the temperature difference between the condenser and the outdoor environment is controlled properly. The second algorithm, which adds one more degree of freedom to control by modulating the indoor fan speed, can improve the transient response because actuator saturations become less likely to occur. The two control algorithms are implemented on a split-type residential air-conditioner and their respective performance is validated experimentally.

  9. Transient and steady-state selection in the striatal microcircuit

    Directory of Open Access Journals (Sweden)

    Adam eTomkins

    2014-01-01

    Full Text Available Although the basal ganglia have been widely studied and implicated in signal processing and action selection, little information is known about the active role the striatal microcircuit plays in action selection in the basal ganglia-thalamo-cortical loops. To address this knowledge gap we use a large scale three dimensional spiking model of the striatum, combined with a rate coded model of the basal ganglia-thalamo-cortical loop, to asses the computational role the striatum plays in action selection. We identify a robust transient phenomena generated by the striatal microcircuit, which temporarily enhances the difference between two competing cortical inputs. We show that this transient is sufficient to modulate decision making in the basal ganglia-thalamo-cortical circuit. We also find that the transient selection originates from a novel adaptation effect in single striatal projection neurons, which is amenable to experimental testing. Finally, we compared transient selection with models implementing classical steady-state selection. We challenged both forms of model to account for recent reports of paradoxically enhanced response selection in Huntington's Disease patients. We found that steady-state selection was uniformly impaired under all simulated Huntington's conditions, but transient selection was enhanced given a sufficient Huntington's-like increase in NMDA receptor sensitivity. Thus our models provide an intriguing hypothesis for the mechanisms underlying the paradoxical cognitive improvements in manifest Huntington's patients.

  10. Loss-of-feedwater transients in PWRs

    International Nuclear Information System (INIS)

    Burns, R.D. III.

    1980-01-01

    Recent severe accident sequence analysis (SASA) work in LASL's Multifault Accident Analysis Section has focused on loss-of-feedwater (LOFW) transients at a 4-loop Westinghouse nuclear power reactor. In all transients studied, the initiator was loss of main feedwater and reactor coolant pump (RCP) trip, caused by temporary loss of off-site power. Subsequent automatic actions included reactor scram, closure of the main steam isolation valves, and initiation of auxiliary feedwater (AFW) flow. TRAC-PD2 calculations were designed to study the consequences of AFW delivery rates below the minimum specified in the emergency operating procedures (EOPs) for the reference 4-loop plant. Six types of LOFW scenarios have been studied, including (1) zero AFW availability (nominal case), (2) initially zero AFW but full recovery after 2 h, (3) zero AFW with steam generator (SG) atmospheric relief valve (ARV) malfunction, (4) zero AFW with high pressure charging flow initiated after 2 h, and (5) zero AFW with delay in reactor scram. Additional cases were considered to study the effects of uncertainties in pressurizer heater/spray operation, operator manual initiation of high pressure charging flow, reactor initial conditions, and RCP and power coastdown characteristics. Nominal case results, rationale for selections of other cases, and lessons learned are summarized

  11. A 3 A sink/source current fast transient response low-dropout Gm driven linear regulator

    International Nuclear Information System (INIS)

    Chu Xiuqin; Li Qingwei; Lai Xinquan; Yuan Bing; Li Yanming; Zhao Yongrui

    2011-01-01

    A 3 A sink/source G m -driven CMOS low-dropout regulator (LDO), specially designed for low input voltage and low cost, is presented by utilizing the structure of a current mirror G m (transconductance) driving technique, which provides high stability as well as a fast load transient response. The proposed LDO was fabricated by a 0.5 μm standard CMOS process, and the die size is as small as 1.0 mm 2 . The proposed LDO dissipates 220 μA of quiescent current in no-load conditions and is able to deliver up to 3 A of load current. The measured results show that the output voltage can be resumed within 2 μs with a less than 1 mV overshoot and undershoot in the output current step from -1.8 to 1.8 A with a 0.1 μs rising and falling time at three 10 μF ceramic capacitors. (semiconductor integrated circuits)

  12. From transient response of a compact photobioreactor for microalgae cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Dilay, Emerson; Ribeiro, Robert Luis Lara; Pulliam, Raevon; Mariano, Andre Bellin [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Nucleo de Pesquisa e Desenvolvimento em Energia Auto-Sustentavel; Ordonez, Juan Carlos [Florida State University, Tallahassee, FL (United States). Dept. of Mechanical Engineering and Center for Advanced Power Systems], E-mail: ordonez@caps.fsu.edu; Vargas, Jose Viriato Coelho [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Biofuels from microalgae are currently the subject of funded scientific research in many countries due to their high productivity of oil when compared with other crops. Microalgae can also be used in many important applications such as to obtain compounds of interest for food, chemicals, and pharmaceuticals. The high productivity of microalgae when compared with other crops is achieved because agricultural land is not mandatory for their cultivation, since they can be grown in open ponds, sea or vertical photo bioreactors. In this paper, a mathematical model is introduced for assessing the transient microalgae growth as a function of variable light intensity, temperature and environmental conditions in the daily cycle. Photo bioreactor geometry is considered as well. Light intensity is obtained from sun position, photo bioreactor geometry, and the installation location in the world. The photo bioreactor was discretized in space by the the volume element method. Balances of energy and species together with thermodynamics, heat transfer and chemistry empirical and theoretical correlations are applied to each volume element. Therefore, a system of ordinary differential equations with respect to time only is capable of delivering temperatures and concentrations as functions of space and time, even with a coarse mesh. The numerical results are capable of predicting the transient and steady state photo bioreactor biomass production with low computational time. Microalgae specific growth rate as a function of average light intensity inside the tubes and time was calculated. As a result, the model is expected to be a useful tool for simulation, design, and optimization of compact photo bioreactors. (author)

  13. Transient flow combustion

    Science.gov (United States)

    Tacina, R. R.

    1984-01-01

    Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

  14. Transient changes of optical properties in semiconductors in response to femtosecond laser pulses

    Czech Academy of Sciences Publication Activity Database

    Tkachenko, V.; Medvedev, Nikita; Ziaja, B.

    2016-01-01

    Roč. 6, č. 9 (2016), 1-12, č. článku 238. ISSN 2076-3417 Institutional support: RVO:68378271 Keywords : free-electron lasers * transient optical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.679, year: 2016

  15. A 2D Daubechies finite wavelet domain method for transient wave response analysis in shear deformable laminated composite plates

    Science.gov (United States)

    Nastos, C. V.; Theodosiou, T. C.; Rekatsinas, C. S.; Saravanos, D. A.

    2018-03-01

    An efficient numerical method is developed for the simulation of dynamic response and the prediction of the wave propagation in composite plate structures. The method is termed finite wavelet domain method and takes advantage of the outstanding properties of compactly supported 2D Daubechies wavelet scaling functions for the spatial interpolation of displacements in a finite domain of a plate structure. The development of the 2D wavelet element, based on the first order shear deformation laminated plate theory is described and equivalent stiffness, mass matrices and force vectors are calculated and synthesized in the wavelet domain. The transient response is predicted using the explicit central difference time integration scheme. Numerical results for the simulation of wave propagation in isotropic, quasi-isotropic and cross-ply laminated plates are presented and demonstrate the high spatial convergence and problem size reduction obtained by the present method.

  16. Learned helplessness: effects of response requirement and interval between treatment and testing.

    Science.gov (United States)

    Hunziker, M H L; Dos Santos, C V

    2007-11-01

    Three experiments investigated learned helplessness in rats manipulating response requirements, shock duration, and intervals between treatment and testing. In Experiment 1, rats previously exposed to uncontrollable or no shocks were tested under one of four different contingencies of negative reinforcement: FR 1 or FR 2 escape contingency for running, and FR1 escape contingency for jumping (differing for the maximum shock duration of 10s or 30s). The results showed that the uncontrollable shocks produced a clear operant learning deficit (learned helplessness effect) only when the animals were tested under the jumping FR 1 escape contingency with 10-s max shock duration. Experiment 2 isolated of the effects of uncontrollability from shock exposure per se and showed that the escape deficit observed using the FR 1 escape jumping response (10-s shock duration) was produced by the uncontrollability of shock. Experiment 3 showed that using the FR 1 jumping escape contingency in the test, the learned helplessness effect was observed one, 14 or 28 days after treatment. These results suggest that running may not be an appropriate test for learned helplessness, and that many diverging results found in the literature might be accounted for by the confounding effects of respondent and operant contingencies present when running is required of rats.

  17. TS-1 and TS-2 transient overpower tests on FFTF fuel

    International Nuclear Information System (INIS)

    Pitner, A.L.; Ferrell, P.C.; Culley, G.E.; Weber, E.T.

    1985-01-01

    The TS-1 and TS-2 TREAT transient experiments subjected a low burnup (2 MWd/kg) and a medium burnup (58 MWd/kg), respectively, FFTF irradiated fuel pin to unprotected 5 cents/s overpower transient conditions. The fuel pin failure response was similar in the two tests, which demonstrated a large margin to failure (P/P 0 > 3) and a favorable upper level failure location. Thus, for these transient conditions, burnup effects on transient performance appeared to be minimal in the range tested. Pin disruption in the medium burnup TS-2 test was more severe due to the higher fission gas pressurization, but failure occurred at only a 5% lower power level than for the low burnup TS-1 fuel pin. Both tests exhibited axial extrusion of molten fuel to the region above the fuel column several seconds before pin failure, demonstrating a potentially beneficial inherent safety mechanism to delay failure and mitigate accident consequences

  18. Real-time Automatic Search for Multi-wavelength Counterparts of DWF Transients

    Science.gov (United States)

    Murphy, Christopher; Cucchiara, Antonino; Andreoni, Igor; Cooke, Jeff; Hegarty, Sarah

    2018-01-01

    The Deeper Wider Faster (DWF) survey aims to find and classify the fastest transients in the Universe. DWF utilizes the Dark Energy Camera (DECam), collecting a continuous sequence of 20s images over a 3 square degree field of view.Once an interesting transient is detected during DWF observations, the DWF collaboration has access to several facilities for rapid follow-up in multiple wavelengths (from gamma to radio).An online web tool has been designed to help with real-time visual classification of possible astrophysical transients in data collected by the DWF observing program. The goal of this project is to create a python-based code to improve the classification process by querying several existing archive databases. Given the DWF transient location and search radius, the developed code will extract a list of possible counterparts and all available information (e.g. magnitude, radio fluxes, distance separation).Thanks to this tool, the human classifier can make a quicker decision in order to trigger the collaboration rapid-response resources.

  19. Environmentally-induced discharge transient coupling to spacecraft

    Science.gov (United States)

    Viswanathan, R.; Barbay, G.; Stevens, N. J.

    1985-01-01

    The Hughes SCREENS (Space Craft Response to Environments of Space) technique was applied to generic spin and 3-axis stabilized spacecraft models. It involved the NASCAP modeling for surface charging and lumped element modeling for transients coupling into a spacecraft. A differential voltage between antenna and spun shelf of approx. 400 V and current of 12 A resulted from discharge at antenna for the spinner and approx. 3 kv and 0.3 A from a discharge at solar panels for the 3-axis stabilized Spacecraft. A typical interface circuit response was analyzed to show that the transients would couple into the Spacecraft System through ground points, which are most vulnerable. A compilation and review was performed on 15 years of available data from electron and ion current collection phenomena. Empirical models were developed to match data and compared with flight data of Pix-1 and Pix-2 mission. It was found that large space power systems would float negative and discharge if operated at or above 300 V. Several recommendations are given to improve the models and to apply them to large space systems.

  20. Arc mRNA induction in striatal efferent neurons associated with response learning.

    Science.gov (United States)

    Daberkow, D P; Riedy, M D; Kesner, R P; Keefe, K A

    2007-07-01

    The dorsal striatum is involved in motor-response learning, but the extent to which distinct populations of striatal efferent neurons are differentially involved in such learning is unknown. Activity-regulated, cytoskeleton-associated (Arc) protein is an effector immediate-early gene implicated in synaptic plasticity. We examined arc mRNA expression in striatopallidal vs. striatonigral efferent neurons in dorsomedial and dorsolateral striatum of rats engaged in reversal learning on a T-maze motor-response task. Male Sprague-Dawley rats learned to turn right or left for 3 days. Half of the rats then underwent reversal training. The remaining rats were yoked to rats undergoing reversal training, such that they ran the same number of trials but ran them as continued-acquisition trials. Brains were removed and processed using double-label fluorescent in situ hybridization for arc and preproenkephalin (PPE) mRNA. In the reversal, but not the continued-acquisition, group there was a significant relation between the overall arc mRNA signal in dorsomedial striatum and the number of trials run, with rats reaching criterion in fewer trials having higher levels of arc mRNA expression. A similar relation was seen between the numbers of PPE(+) and PPE(-) neurons in dorsomedial striatum with cytoplasmic arc mRNA expression. Interestingly, in behaviourally activated animals significantly more PPE(-) neurons had cytoplasmic arc mRNA expression. These data suggest that Arc in both striatonigral and striatopallidal efferent neurons is involved in striatal synaptic plasticity mediating motor-response learning in the T-maze and that there is differential processing of arc mRNA in distinct subpopulations of striatal efferent neurons.

  1. An efficient Neuro-Fuzzy approach to nuclear power plant transient identification

    Energy Technology Data Exchange (ETDEWEB)

    Gomes da Costa, Rafael [Instituto de Engenharia Nuclear - CNEN, Programa de Pos-Graduacao em Ciencia e Tecnologia Nucleares, Via Cinco, s/no, Cidade Universitaria, Rua Helio de Almeida, 75, Postal Box 68550, Zip Code 21941-906 Rio de Janeiro (Brazil); Abreu Mol, Antonio Carlos de, E-mail: mol@ien.gov.br [Instituto de Engenharia Nuclear - CNEN, Programa de Pos-Graduacao em Ciencia e Tecnologia Nucleares, Via Cinco, s/no, Cidade Universitaria, Rua Helio de Almeida, 75, Postal Box 68550, Zip Code 21941-906 Rio de Janeiro (Brazil); Instituto Nacional de C and T de Reatores Nucleares Inovadores (Brazil); Carvalho, Paulo Victor R. de, E-mail: paulov@ien.gov.br [Instituto de Engenharia Nuclear - CNEN, Programa de Pos-Graduacao em Ciencia e Tecnologia Nucleares, Via Cinco, s/no, Cidade Universitaria, Rua Helio de Almeida, 75, Postal Box 68550, Zip Code 21941-906 Rio de Janeiro (Brazil); Lapa, Celso Marcelo Franklin, E-mail: lapa@ien.gov.br [Instituto de Engenharia Nuclear - CNEN, Programa de Pos-Graduacao em Ciencia e Tecnologia Nucleares, Via Cinco, s/no, Cidade Universitaria, Rua Helio de Almeida, 75, Postal Box 68550, Zip Code 21941-906 Rio de Janeiro (Brazil); Instituto Nacional de C and T de Reatores Nucleares Inovadores (Brazil)

    2011-06-15

    Highlights: > We investigate a Neuro-Fuzzy modeling tool use for able transient identification. > The prelusive transient type identification is done by an artificial neural network. > After, the fuzzy-logic system analyzes the results emitting reliability degree of it. > The research support was made in a PWR simulator at the Brazilian Nuclear Engineering Institute. > The results show the potential to help operators' decisions in a nuclear power plant. - Abstract: Transient identification in nuclear power plants (NPP) is often a computational very hard task and may involve a great amount of human cognition. The early identification of unexpected departures from steady state behavior is an essential step for the operation, control and accident management in NPPs. The bases for the transient identification relay on the evidence that different system faults and anomalies lead to different pattern evolution in the involved process variables. During an abnormal event, the operator must monitor a great amount of information from the instruments that represents a specific type of event. Recently, several works have been developed for transient identification. These works frequently present a non reliable response, using the 'don't know' as the system output. In this work, we investigate the possibility of using a Neuro-Fuzzy modeling tool for efficient transient identification, aiming to helping the operator crew to take decisions relative to the procedure to be followed in situations of accidents/transients at NPPs. The proposed system uses artificial neural networks (ANN) as first level transient diagnostic. After the ANN has done the preliminary transient type identification, a fuzzy-logic system analyzes the results emitting reliability degree of it. A validation of this identification system was made at the three loops Pressurized Water Reactor (PWR) simulator of the Human-System Interface Laboratory (LABIHS) of the Nuclear Engineering Institute

  2. An efficient Neuro-Fuzzy approach to nuclear power plant transient identification

    International Nuclear Information System (INIS)

    Gomes da Costa, Rafael; Abreu Mol, Antonio Carlos de; Carvalho, Paulo Victor R. de; Lapa, Celso Marcelo Franklin

    2011-01-01

    Highlights: → We investigate a Neuro-Fuzzy modeling tool use for able transient identification. → The prelusive transient type identification is done by an artificial neural network. → After, the fuzzy-logic system analyzes the results emitting reliability degree of it. → The research support was made in a PWR simulator at the Brazilian Nuclear Engineering Institute. → The results show the potential to help operators' decisions in a nuclear power plant. - Abstract: Transient identification in nuclear power plants (NPP) is often a computational very hard task and may involve a great amount of human cognition. The early identification of unexpected departures from steady state behavior is an essential step for the operation, control and accident management in NPPs. The bases for the transient identification relay on the evidence that different system faults and anomalies lead to different pattern evolution in the involved process variables. During an abnormal event, the operator must monitor a great amount of information from the instruments that represents a specific type of event. Recently, several works have been developed for transient identification. These works frequently present a non reliable response, using the 'don't know' as the system output. In this work, we investigate the possibility of using a Neuro-Fuzzy modeling tool for efficient transient identification, aiming to helping the operator crew to take decisions relative to the procedure to be followed in situations of accidents/transients at NPPs. The proposed system uses artificial neural networks (ANN) as first level transient diagnostic. After the ANN has done the preliminary transient type identification, a fuzzy-logic system analyzes the results emitting reliability degree of it. A validation of this identification system was made at the three loops Pressurized Water Reactor (PWR) simulator of the Human-System Interface Laboratory (LABIHS) of the Nuclear Engineering Institute (IEN

  3. The unique sound of the uni-vibe pedal: Part II. Transient behaviour

    Science.gov (United States)

    Hahlweg, Cornelius F.; Rothe, Hendrik

    2013-09-01

    The Uni-Vibe is an effect pedal mostly used by electric guitar players. It is based on an opto-electronically controlled all-pass chain. In last year's paper on the subject an idealized system model was derived, which lead to deeper discussion of the musical consequences of the effect in terms of harmonic analysis of single tones and chords in clean and distorted mode. As a direct continuation the present paper deals with the transient behaviour of the device. The transient response is essential for understanding the special sound character, the reaction on picking techniques and the interaction with certain instruments. Therefore the system model is expanded and the pulse response of the idealized time invariant system is derived.

  4. Characterizing hydraulic fractures in shale gas reservoirs using transient pressure tests

    Directory of Open Access Journals (Sweden)

    Cong Wang

    2015-06-01

    This work presents an unconventional gas reservoir simulator and its application to quantify hydraulic fractures in shale gas reservoirs using transient pressure data. The numerical model incorporates most known physical processes for gas production from unconventional reservoirs, including two-phase flow of liquid and gas, Klinkenberg effect, non-Darcy flow, and nonlinear adsorption. In addition, the model is able to handle various types and scales of fractures or heterogeneity using continuum, discrete or hybrid modeling approaches under different well production conditions of varying rate or pressure. Our modeling studies indicate that the most sensitive parameter of hydraulic fractures to early transient gas flow through extremely low permeability rock is actually the fracture-matrix contacting area, generated by fracturing stimulation. Based on this observation, it is possible to use transient pressure testing data to estimate the area of fractures generated from fracturing operations. We will conduct a series of modeling studies and present a methodology using typical transient pressure responses, simulated by the numerical model, to estimate fracture areas created or to quantity hydraulic fractures with traditional well testing technology. The type curves of pressure transients from this study can be used to quantify hydraulic fractures in field application.

  5. Fast transient current response to switching events in short chains of molecular islands

    Czech Academy of Sciences Publication Activity Database

    Kalvová, Anděla; Špička, Václav; Velický, B.

    2013-01-01

    Roč. 26, č. 4 (2013), s. 773-777 ISSN 1557-1939 R&D Projects: GA ČR GAP204/12/0897 Institutional support: RVO:68378271 Keywords : nonequilibrium * molecular islands * initial correlations * transient currents Subject RIV: BE - Theoretical Physics Impact factor: 0.930, year: 2013

  6. Predicting decadal trends and transient responses of radiocarbon storage and fluxes in a temperate forest soil

    Directory of Open Access Journals (Sweden)

    C. A. Sierra

    2012-08-01

    Full Text Available Representing the response of soil carbon dynamics to global environmental change requires the incorporation of multiple tools in the development of predictive models. An important tool to construct and test models is the incorporation of bomb radiocarbon in soil organic matter during the past decades. In this manuscript, we combined radiocarbon data and a previously developed empirical model to explore decade-scale soil carbon dynamics in a temperate forest ecosystem at the Harvard Forest, Massachusetts, USA. We evaluated the contribution of different soil C fractions to both total soil CO2 efflux and microbially respired C. We tested the performance of the model based on measurable soil organic matter fractions against a decade of radiocarbon measurements. The model was then challenged with radiocarbon measurements from a warming and N addition experiment to test multiple hypotheses about the different response of soil C fractions to the experimental manipulations. Our results showed that the empirical model satisfactorily predicts the trends of radiocarbon in litter, density fractions, and respired CO2 observed over a decade in the soils not subjected to manipulation. However, the model, modified with prescribed relationships for temperature and decomposition rates, predicted most but not all the observations from the field experiment where soil temperatures and nitrogen levels were increased, suggesting that a larger degree of complexity and mechanistic relations need to be added to the model to predict short-term responses and transient dynamics.

  7. Transient analysis of the IRIS reactor

    International Nuclear Information System (INIS)

    Bajs, T.; Oriani, L.; Ricotti, M.E.; Barroso, A.C.

    2002-01-01

    An international consortium of industry, laboratory, university and utility establishments, led by Westinghouse, is developing a modular, integral, light water cooled, small to medium power reactor, the International Reactor Innovative and Secure (IRIS). IRIS features innovative, advanced engineering, but it is firmly based on the proven technology of pressurized water reactors (PWR). Given the large number of organizations involved in the IRIS design, the RELAP5/MOD 3.3 code has been selected as the main system code. A nodalization of the reference IRIS design has been developed with a basic set of protective functions and controls. Engineered Safety Features of the concept are being also implemented, and in particular the Emergency Heat Removal System that is used for safety grade decay heat removal and in the small break LOCA response of IRIS (Large break LOCAs are eliminated in IRIS by the adoption of the Integral layout) This paper discusses developed model and transient behavior of the system for representative transient sequences.(author)

  8. Accelerating transient simulation of linear reduced order models.

    Energy Technology Data Exchange (ETDEWEB)

    Thornquist, Heidi K.; Mei, Ting; Keiter, Eric Richard; Bond, Brad

    2011-10-01

    Model order reduction (MOR) techniques have been used to facilitate the analysis of dynamical systems for many years. Although existing model reduction techniques are capable of providing huge speedups in the frequency domain analysis (i.e. AC response) of linear systems, such speedups are often not obtained when performing transient analysis on the systems, particularly when coupled with other circuit components. Reduced system size, which is the ostensible goal of MOR methods, is often insufficient to improve transient simulation speed on realistic circuit problems. It can be shown that making the correct reduced order model (ROM) implementation choices is crucial to the practical application of MOR methods. In this report we investigate methods for accelerating the simulation of circuits containing ROM blocks using the circuit simulator Xyce.

  9. TRANSPA: a code for transient thermal analysis of a single fuel pin

    International Nuclear Information System (INIS)

    Prenger, F.C.

    1985-02-01

    An analytical model (TRANSPA) for the transient thermal analysis of a single uranium carbide fuel pin was developed. This model uses thermal boundary conditions obtained from COBRA-WC output and calculates the transient thermal response of a single fuel pin to changes in internal power generation, coolant flowrate, or fuel pin physical configuration. The model uses the MITAS finite difference thermal analyzer. MITAS provides the means to input separate conductance models through the use of a user subroutine input capability. The model is a lumped-mass representation of the fuel pin using 26 nodes and 42 conductors. Run time for each transient analysis is approximately one minute of central processor time on the NOS operating system

  10. Learning and Growing: Trust, Leadership, and Response to Crisis

    Science.gov (United States)

    Sutherland, Ian E.

    2017-01-01

    Purpose: The purpose of this paper is to explore the nature of trust in a school community related to the leadership response to crisis. Design/Methodology/Approach: This study was a multiple-source qualitative study of a single case of a PreK-12 international school called The Learning School. Findings: The findings revealed the nature of how…

  11. ATTITUDES TOWARDS LEARNING ENGLISH: A STUDY OF MOTIVATION AND RESPONSIBILITY AS AIDS TO HUMAN RESOURCES

    Directory of Open Access Journals (Sweden)

    Monica-Ariana Sim

    2014-03-01

    Full Text Available The paper presents the results of a survey carried out at the Faculty of Economic Sciences, University of Oradea, in order to identify attitudes, beliefs, motivation and self-responsibility among students when it comes to learning the English language. The main issue investigated was motivation set at the basis of the learning process together with students’ attitudes regarding the use of English in the Romanian social and educational context, as well as the use of the English language in general. A valid questionnaire was designed and tried to a convenient sample of students; the results of the study are discussed in terms of the principal components that were established including attitude towards motivation, self-responsibility, and language learning approaches. Research and experience show that English is of utmost importance in the academic and future professional lives of students majoring in economics. Therefore, this paper provides some theoretical aspects of motivation, beliefs and responsibility in the context of second language acquisition.Among the important achievements of the study we should mention the observations of students’ behaviour concerning responsibility. It appears that most students are not ready to take complete responsibility for learning. They are either afraid of the teacher, or feel embarrassed, and are ashamed to openly utter their ideas. Thus, teamwork and pair-work facilitate the effective learning of the foreign language and encourage students’ collaboration. The teacher is not the central actor, the controller anymore; s/he becomes the facilitator and source of knowledge. It is important for the teacher to know the basic needs of his/her students and cater for these according to level of their importance, to be aware of the reasons that propel students towards learning, improving or just surviving English as a foreign language.

  12. Modeling individuals’ cognitive and affective responses in spatial learning behavior

    NARCIS (Netherlands)

    Han, Q.; Arentze, T.A.; Timmermans, H.J.P.; Janssens, D.; Wets, G.; Lo, H.P.; Leung, Stephen C.H.; Tan, Susanna M.L.

    2008-01-01

    Activity-based analysis has slowly shifted gear from analysis of daily activity patterns to analysis and modeling of dynamic activity-travel patterns. In this paper, we describe a dynamic model that is concerned with simulating cognitive and affective responses in spatial learning behavior for a

  13. The improved quasi-static method vs the direct method: a case study for CANDU reactor transients

    International Nuclear Information System (INIS)

    Kaveh, S.; Koclas, J.; Roy, R.

    1999-01-01

    Among the large number of methods for the transient analysis of nuclear reactors, the improved quasi-static procedure is one of the most widely used. In recent years, substantial increase in both computer speed and memory has motivated a rethinking of the limitations of this method. The overall goal of the present work is a systematic comparison between the improved quasi-static and the direct method (mesh-centered finite difference) for realistic CANDU transient simulations. The emphasis is on the accuracy of the solutions as opposed to the computational speed. Using the computer code NDF, a typical realistic transient of CANDU reactor has been analyzed. In this transient the response of the reactor regulating system to a substantial local perturbation (sudden extraction of the five adjuster rods) has been simulated. It is shown that when updating the detector responses is of major importance, it is better to use a well-optimized direct method rather than the improved quasi-static method. (author)

  14. Transient potentials in dendritic systems of arbitrary geometry.

    Science.gov (United States)

    Butz, E G; Cowan, J D

    1974-09-01

    A simple graphical calculus is developed that generates analytic solutions for membrane potential transforms at any point on the dendritic tree of neurons with arbitrary dendritic geometries, in response to synaptic "current" inputs. Such solutions permit the computation of transients in neurons with arbitrary geometry and may facilitate analysis of the role of dendrites in such cells.

  15. Investigation of practical use situation and performance for electric transient analysis programs in the U.S. nuclear power plants

    International Nuclear Information System (INIS)

    Shimada, Yoshio

    2010-01-01

    The purposes of the present study are firstly to investigate the status of practical use of electric transient analysis programs used in U.S. nuclear power plants, which has been extracted as good examples from the information analysis of overseas troubles, and secondly to select a program to be recommended for use in implementing electric transient analysis in domestic nuclear power plants. In addition, to promote its practical use, a selected electric transient analysis program was tested by simulating the transient response during a load sequence test of an emergency diesel generator (EDG) in a domestic representative nuclear plant to evaluate its simulation accuracy by comparing its result with the measured plant data. The results obtained are as follows: (1) In U.S. nuclear power plants, simulations using electric transient analysis programs, such as ETAP, EMPT, etc., are widely performed, which contributed to improve the plant safety. (2) A selected transient analysis program EMTP was verified in its accuracy in terms of transient response of active power, current, voltage and frequency of the EDG during the load sequence test in a domestic representative nuclear power plant. (author)

  16. Transient response in granular quasi-two-dimensional bounded heap flow.

    Science.gov (United States)

    Xiao, Hongyi; Ottino, Julio M; Lueptow, Richard M; Umbanhowar, Paul B

    2017-10-01

    We study the transition between steady flows of noncohesive granular materials in quasi-two-dimensional bounded heaps by suddenly changing the feed rate. In both experiments and simulations, the primary feature of the transition is a wedge of flowing particles that propagates downstream over the rising free surface with a wedge front velocity inversely proportional to the square root of time. An additional longer duration transient process continues after the wedge front reaches the downstream wall. The entire transition is well modeled as a moving boundary problem with a diffusionlike equation derived from local mass balance and a local relation between the flux and the surface slope.

  17. Learning to be Responsible? A Systems View of the Organization-Environment Relationship

    OpenAIRE

    Amanda, Gregory

    2005-01-01

    In this paper the issue of whether organizations can learn to become responsible will be addressed. Zadek [1] suggests that organizations ‘pass through 5 stages of corporate responsibility: 1. defensive, 2. compliance, 3. managerial, 4. strategic, and 5. civil’. Further, Zadek argues that responsibility cannot be achieved without an external focus, “Beyond just getting their own houses in order, companies need to stay abreast of the public’s ideas about corporate roles and responsibilities.” ...

  18. Primary School Pupils' Response to Audio-Visual Learning Process in Port-Harcourt

    Science.gov (United States)

    Olube, Friday K.

    2015-01-01

    The purpose of this study is to examine primary school children's response on the use of audio-visual learning processes--a case study of Chokhmah International Academy, Port-Harcourt (owned by Salvation Ministries). It looked at the elements that enhance pupils' response to educational television programmes and their hindrances to these…

  19. Using the Transient Response of WO3 Nanoneedles under Pulsed UV Light in the Detection of NH3 and NO2

    Directory of Open Access Journals (Sweden)

    Oriol Gonzalez

    2018-04-01

    Full Text Available Here we report on the use of pulsed UV light for activating the gas sensing response of metal oxides. Under pulsed UV light, the resistance of metal oxides presents a ripple due to light-induced transient adsorption and desorption phenomena. This methodology has been applied to tungsten oxide nanoneedle gas sensors operated either at room temperature or under mild heating (50 °C or 100 °C. It has been found that by analyzing the rate of resistance change caused by pulsed UV light, a fast determination of gas concentration is achieved (ten-fold improvement in response time. The technique is useful for detecting both oxidizing (NO2 and reducing (NH3 gases, even in the presence of different levels of ambient humidity. Room temperature operated sensors under pulsed UV light show good response towards ammonia and nitrogen dioxide at low power consumption levels. Increasing their operating temperature to 50 °C or 100 °C has the effect of further increasing sensitivity.

  20. Investigating the impact of in-vehicle transients on diesel soot emissions

    Directory of Open Access Journals (Sweden)

    Filipi Zoran

    2008-01-01

    Full Text Available This paper describes development of a test cell setup for concurrent running of a real engine and a simulation of the vehicle system, and its use for investigating highly-dynamic engine-in-vehicle operation and its effect on diesel engine emissions. Running an engine in the test cell under conditions experienced in the vehicle enables acquiring detailed insight into dynamic interactions between power train sub-systems, and the impact of it on fuel consumption and transient emissions. This type of data may otherwise be difficult and extremely costly to obtain from a vehicle prototype test. In particular, engine system response during critical transients and the effect of transient excursions on emissions are investigated using advanced, fast-response test instrumentation and emissions analyzers. Main enablers of the work include the highly dynamic AC electric dynamometer with the accompanying computerized control system and the computationally efficient simulation of the driveline/vehicle system. The latter is developed through systematic energy-based proper modeling that tailors the virtual model to capture critical powertrain transients while running in real time. Coupling the real engine with the virtual driveline/vehicle offers a chance to easily modify vehicle parameters, and even study different power train configurations. In particular, the paper describes the engine-in-the-loop study of a V-8, 6l engine coupled to a virtual 4´4 off road vehicle. This engine is considered as a high-performance option for this truck and the real prototype of the complete vehicle does not exist yet. The results shed light on critical transients in a conventional powertrain and their effect on NOx and soot emissions. Measurements demonstrate very large spikes of particulate concentration at the initiation of vehicle acceleration events. Characterization of transients and their effect on particulate emission provides a basis for devising engine-level or

  1. Machine-learning-based Brokers for Real-time Classification of the LSST Alert Stream

    Science.gov (United States)

    Narayan, Gautham; Zaidi, Tayeb; Soraisam, Monika D.; Wang, Zhe; Lochner, Michelle; Matheson, Thomas; Saha, Abhijit; Yang, Shuo; Zhao, Zhenge; Kececioglu, John; Scheidegger, Carlos; Snodgrass, Richard T.; Axelrod, Tim; Jenness, Tim; Maier, Robert S.; Ridgway, Stephen T.; Seaman, Robert L.; Evans, Eric Michael; Singh, Navdeep; Taylor, Clark; Toeniskoetter, Jackson; Welch, Eric; Zhu, Songzhe; The ANTARES Collaboration

    2018-05-01

    The unprecedented volume and rate of transient events that will be discovered by the Large Synoptic Survey Telescope (LSST) demand that the astronomical community update its follow-up paradigm. Alert-brokers—automated software system to sift through, characterize, annotate, and prioritize events for follow-up—will be critical tools for managing alert streams in the LSST era. The Arizona-NOAO Temporal Analysis and Response to Events System (ANTARES) is one such broker. In this work, we develop a machine learning pipeline to characterize and classify variable and transient sources only using the available multiband optical photometry. We describe three illustrative stages of the pipeline, serving the three goals of early, intermediate, and retrospective classification of alerts. The first takes the form of variable versus transient categorization, the second a multiclass typing of the combined variable and transient data set, and the third a purity-driven subtyping of a transient class. Although several similar algorithms have proven themselves in simulations, we validate their performance on real observations for the first time. We quantitatively evaluate our pipeline on sparse, unevenly sampled, heteroskedastic data from various existing observational campaigns, and demonstrate very competitive classification performance. We describe our progress toward adapting the pipeline developed in this work into a real-time broker working on live alert streams from time-domain surveys.

  2. Reading and response as facilitation to the teaching and learning of ...

    African Journals Online (AJOL)

    Reading and response as facilitation to the teaching and learning of ... and strategies that can be used in the classroom towards teaching student's reading skills. ... The population comprises all forth year English teaching methods class.

  3. Discriminative learning of receptive fields from responses to non-Gaussian stimulus ensembles.

    Science.gov (United States)

    Meyer, Arne F; Diepenbrock, Jan-Philipp; Happel, Max F K; Ohl, Frank W; Anemüller, Jörn

    2014-01-01

    Analysis of sensory neurons' processing characteristics requires simultaneous measurement of presented stimuli and concurrent spike responses. The functional transformation from high-dimensional stimulus space to the binary space of spike and non-spike responses is commonly described with linear-nonlinear models, whose linear filter component describes the neuron's receptive field. From a machine learning perspective, this corresponds to the binary classification problem of discriminating spike-eliciting from non-spike-eliciting stimulus examples. The classification-based receptive field (CbRF) estimation method proposed here adapts a linear large-margin classifier to optimally predict experimental stimulus-response data and subsequently interprets learned classifier weights as the neuron's receptive field filter. Computational learning theory provides a theoretical framework for learning from data and guarantees optimality in the sense that the risk of erroneously assigning a spike-eliciting stimulus example to the non-spike class (and vice versa) is minimized. Efficacy of the CbRF method is validated with simulations and for auditory spectro-temporal receptive field (STRF) estimation from experimental recordings in the auditory midbrain of Mongolian gerbils. Acoustic stimulation is performed with frequency-modulated tone complexes that mimic properties of natural stimuli, specifically non-Gaussian amplitude distribution and higher-order correlations. Results demonstrate that the proposed approach successfully identifies correct underlying STRFs, even in cases where second-order methods based on the spike-triggered average (STA) do not. Applied to small data samples, the method is shown to converge on smaller amounts of experimental recordings and with lower estimation variance than the generalized linear model and recent information theoretic methods. Thus, CbRF estimation may prove useful for investigation of neuronal processes in response to natural stimuli and

  4. Discriminative learning of receptive fields from responses to non-Gaussian stimulus ensembles.

    Directory of Open Access Journals (Sweden)

    Arne F Meyer

    Full Text Available Analysis of sensory neurons' processing characteristics requires simultaneous measurement of presented stimuli and concurrent spike responses. The functional transformation from high-dimensional stimulus space to the binary space of spike and non-spike responses is commonly described with linear-nonlinear models, whose linear filter component describes the neuron's receptive field. From a machine learning perspective, this corresponds to the binary classification problem of discriminating spike-eliciting from non-spike-eliciting stimulus examples. The classification-based receptive field (CbRF estimation method proposed here adapts a linear large-margin classifier to optimally predict experimental stimulus-response data and subsequently interprets learned classifier weights as the neuron's receptive field filter. Computational learning theory provides a theoretical framework for learning from data and guarantees optimality in the sense that the risk of erroneously assigning a spike-eliciting stimulus example to the non-spike class (and vice versa is minimized. Efficacy of the CbRF method is validated with simulations and for auditory spectro-temporal receptive field (STRF estimation from experimental recordings in the auditory midbrain of Mongolian gerbils. Acoustic stimulation is performed with frequency-modulated tone complexes that mimic properties of natural stimuli, specifically non-Gaussian amplitude distribution and higher-order correlations. Results demonstrate that the proposed approach successfully identifies correct underlying STRFs, even in cases where second-order methods based on the spike-triggered average (STA do not. Applied to small data samples, the method is shown to converge on smaller amounts of experimental recordings and with lower estimation variance than the generalized linear model and recent information theoretic methods. Thus, CbRF estimation may prove useful for investigation of neuronal processes in response to

  5. RETRAN operational transient analysis of the Big Rock Point plant boiling water reactor

    International Nuclear Information System (INIS)

    Sawtelle, G.R.; Atchison, J.D.; Farman, R.F.; VandeWalle, D.J.; Bazydlo, H.G.

    1983-01-01

    Energy Incorporated used the RETRAN computer code to model and calculate nine Consumers Power Company Big Rock Point Nuclear Power Plant transients. RETRAN, a best-estimate, one-dimensional, homogeneous-flow thermal-equilibrium code, is applicable to FSAR Chapter 15 transients for Conditions 1 through IV. The BWR analyses were performed in accordance with USNRC Standard Review Plan criteria and in response to the USNRC Systematic Evaluation Program. The RETRAN Big Rock Point model was verified by comparison to plant startup test data. This paper discusses the unique modeling techniques used in RETRAN to model this steam-drum-type BWR. Transient analyses results are also presented

  6. Teaching Personal and Social Responsibility and Transfer of Learning: Opportunities and Challenges for Teachers and Coaches

    Science.gov (United States)

    Gordon, Barrie; Doyle, Stephanie

    2015-01-01

    The transfer of learning from the gym to other areas of participants' lives has always been a core component of the Teaching Personal and Social Responsibility Model. The degree to which transfer of learning is successfully facilitated in the reality of Teaching Personal and Social Responsibility Model-based teaching and coaching is, however,…

  7. Fuel rod response to BWR power oscillations during anticipated transient without scram

    International Nuclear Information System (INIS)

    Cunningham, M.; Scott, H.

    1998-01-01

    The US NRC is examining fuel behaviour during a postulated BWR anticipated transient without scram (ATWS) with power oscillations to determine if current regulatory criteria are adequate. Currently, the 280 cal/g limit for RIAs is used to show that coolable geometry is maintained and pressure pulses are avoided during ATWSs. Two specific questions have now been raised about the continued use of the 280 cal/g value. First, this value was derived from energy deposition values whereas the regulatory requirements are written in terms of fuel enthalpy. The second is that fuel rod rupture with fuel dispersal has been observed in RIA tests with high bum-up fuel rods having energy deposition values well below the current limit. However, the BWR ATWS power oscillation transient is slower than a RIA power pulse, thus reducing the likelihood of failure. Therefore questions about the adequacy of the 280 cal/g limit do not necessarily imply unacceptable fuel damage occurring during such power oscillations and there is no immediate safety concern. The reported analysis, using the FRAPTRAN transient fuel rod analysis code, was thus undertaken to determine if further investigation might be appropriate and with the intention of starting some discussions about the issue. There was a comment that a limit of 100 cal/g fuel enthalpy had been mentioned following the scoping calculations but that perhaps enthalpy was not the main concern in an ATWS. It was also observed that cladding stresses are lower than in all RIA. The question was what really is the main concern. It was replied that the main concern was a question of maintaining a coolable geometry i.e. not loosing fuel particles out of the rod. And it was agreed that enthalpy may not be the important issue, rather that it previously had been used as the parameter and so had been considered. Confirmation of this presently being an evaluation and not a regulatory concern was sought and provided, it being pointed out that the NRC

  8. Influence of transient flooding on methane fluxes from subtropical pastures

    Science.gov (United States)

    Seasonally flooded subtropical pastures are major methane (CH4) sources, where transient flooding drives episodic and high-magnitude emissions from the underlying landscape. Understanding the mechanisms that drive these patterns is needed to better understand pasture CH4 emissions and their response...

  9. Concurrent Unimodal Learning Enhances Multisensory Responses of Bi-Directional Crossmodal Learning in Robotic Audio-Visual Tracking

    DEFF Research Database (Denmark)

    Shaikh, Danish; Bodenhagen, Leon; Manoonpong, Poramate

    2018-01-01

    modalities to independently update modality-specific neural weights on a moment-by-moment basis, in response to dynamic changes in noisy sensory stimuli. The circuit is embodied as a non-holonomic robotic agent that must orient a towards a moving audio-visual target. The circuit continuously learns the best...

  10. Information-integration category learning and the human uncertainty response.

    Science.gov (United States)

    Paul, Erick J; Boomer, Joseph; Smith, J David; Ashby, F Gregory

    2011-04-01

    The human response to uncertainty has been well studied in tasks requiring attention and declarative memory systems. However, uncertainty monitoring and control have not been studied in multi-dimensional, information-integration categorization tasks that rely on non-declarative procedural memory. Three experiments are described that investigated the human uncertainty response in such tasks. Experiment 1 showed that following standard categorization training, uncertainty responding was similar in information-integration tasks and rule-based tasks requiring declarative memory. In Experiment 2, however, uncertainty responding in untrained information-integration tasks impaired the ability of many participants to master those tasks. Finally, Experiment 3 showed that the deficit observed in Experiment 2 was not because of the uncertainty response option per se, but rather because the uncertainty response provided participants a mechanism via which to eliminate stimuli that were inconsistent with a simple declarative response strategy. These results are considered in the light of recent models of category learning and metacognition.

  11. Impaired Expected Value Computations Coupled With Overreliance on Stimulus-Response Learning in Schizophrenia.

    Science.gov (United States)

    Hernaus, Dennis; Gold, James M; Waltz, James A; Frank, Michael J

    2018-04-03

    While many have emphasized impaired reward prediction error signaling in schizophrenia, multiple studies suggest that some decision-making deficits may arise from overreliance on stimulus-response systems together with a compromised ability to represent expected value. Guided by computational frameworks, we formulated and tested two scenarios in which maladaptive representations of expected value should be most evident, thereby delineating conditions that may evoke decision-making impairments in schizophrenia. In a modified reinforcement learning paradigm, 42 medicated people with schizophrenia and 36 healthy volunteers learned to select the most frequently rewarded option in a 75-25 pair: once when presented with a more deterministic (90-10) pair and once when presented with a more probabilistic (60-40) pair. Novel and old combinations of choice options were presented in a subsequent transfer phase. Computational modeling was employed to elucidate contributions from stimulus-response systems (actor-critic) and expected value (Q-learning). People with schizophrenia showed robust performance impairments with increasing value difference between two competing options, which strongly correlated with decreased contributions from expected value-based learning (Q-learning). Moreover, a subtle yet consistent contextual choice bias for the probabilistic 75 option was present in people with schizophrenia, which could be accounted for by a context-dependent reward prediction error in the actor-critic. We provide evidence that decision-making impairments in schizophrenia increase monotonically with demands placed on expected value computations. A contextual choice bias is consistent with overreliance on stimulus-response learning, which may signify a deficit secondary to the maladaptive representation of expected value. These results shed new light on conditions under which decision-making impairments may arise. Copyright © 2018 Society of Biological Psychiatry. Published by

  12. The effect of high-flux H plasma exposure with simultaneous transient heat loads on tungsten surface damage and power handling

    NARCIS (Netherlands)

    van Eden, G. G.; Morgan, T. W.; van der Meiden, H. J.; J Matejicek,; T Chraska,; Wirtz, M.; De Temmerman, G.

    2014-01-01

    The performance of the full-W ITER divertor may be significantly affected by the interplay between steady-state plasma exposure and transient events. To address this issue, the effect of a high-flux H plasma on the thermal shock response of W to ELM-like transients has been investigated. Transient

  13. Learning Responsibility and Balance of Power

    Directory of Open Access Journals (Sweden)

    Şefika Sümeyye Çam

    2014-01-01

    Full Text Available This qualitative study aims to determine teacher perspectives on learning responsibility and balance of power. The research design is case study which was conducted on four primary school teachers. The data were collected with semi-structured interviews and the data obtained were analyzed with categorical analysis, a type of content analysis. The findings suggest that teachers think that learner should be at the center of teaching with LCT and they are incapable of applying learner-center teaching. It has been found that the class size and loaded teaching programs prevent them to apply LCT. Therefore, there have been some recommendations about the LCT by the researchers of the study.

  14. Extinguishing a learned response in a free-ranging gray wolf (Canis lupus)

    Science.gov (United States)

    Mech, L. David

    2017-01-01

    A free-ranging Gray Wolf (Canis lupus), habituated to human presence (the author) on Ellesmere Island, Canada, learned to anticipate experimental feeding by a human, became impatient, persistent, and bold and exhibited stalking behaviour toward the food source. Only after the author offered the wolf about 90 clumps of dry soil over a period of 45 minutes in three bouts, did the wolf give up this behaviour. To my knowledge, this is the first example of extinguishing a learned response in a free-ranging wolf and provides new insight into the learning behaviour of such animals.

  15. Transient electromagnetic scattering on anisotropic media

    International Nuclear Information System (INIS)

    Stewart, R.D.

    1990-01-01

    This dissertation treats the problem of transient scattering of obliquely incident electromagnetic plane waves on a stratified anisotropic dielectric slab. Scattering operators are derived for the reflective response of the medium. The internal fields are calculated. Wave splitting and invariant imbedding techniques are used. These techniques are first presented for fields normally incident on a stratified, isotropic dielectric medium. The techniques of wave splitting and invariant imbedding are applied to normally incident plane waves on an anisotropic medium. An integro-differential equation is derived for the reflective response and the direct and inverse scattering problems are discussed. These techniques are applied to the case of obliquely incident plane waves. The reflective response is derived and the direct and inverse problems discussed and compared to those for the normal incidence case. The internal fields are investigated for the oblique incidence via a Green's function approach. A numerical scheme is presented to calculate the Green's function. Finally, symmetry relations of the reflective response are discussed

  16. Do Magnetic Fields drive high-energy explosive transients?

    OpenAIRE

    Mundell, Carole

    2017-01-01

    I will review the current state-of-the-art in real-time, rapid response optical imaging and polarimetric followup of transient sources such as Gamma Ray Bursts. I will interpret current results within the context of the external shock model and present predictions for future mm- and cm-wave radio observatories. Recent observational results from new radio pilot studies will also be presented.

  17. Do Magnetic Fields Drive High-Energy Explosive Transients?

    Science.gov (United States)

    Mundell, Carole

    2017-10-01

    I will review the current state-of-the-art in real-time, rapid response optical imaging and polarimetric followup of transient sources such as Gamma Ray Bursts. I will interpret current results within the context of the external shock model and present predictions for future mm- and cm-wave radio observatories. Recent observational results from new radio pilot studies will also be presented.

  18. Stress Induces a Shift Towards Striatum-Dependent Stimulus-Response Learning via the Mineralocorticoid Receptor

    NARCIS (Netherlands)

    Vogel, S.; Klumpers, F.; Navarro Schröder, T.; Oplaat, K.T.; Krugers, H.J.; Oitzl, M.S.; Joëls, M.; Doeller, C.F.; Fernández, G.

    2017-01-01

    Stress is assumed to cause a shift from flexible 'cognitive' memory to more rigid 'habit' memory. In the spatial memory domain, stress impairs place learning depending on the hippocampus whereas stimulus-response learning based on the striatum appears to be improved. While the neural basis of this

  19. Stress induces a shift towards striatum-dependent stimulus-response learning via the mineralocorticoid receptor

    NARCIS (Netherlands)

    Vogel, S.; Klumpers, F.; Navarro Schröder, T.; Oplaat, K.T.; Krugers, H.J.; Oitzl, M.S.; Joëls, M.; Doeller, C.F.; Fernandez, G.

    2017-01-01

    Stress is assumed to cause a shift from flexible 'cognitive' memory to more rigid 'habit' memory. In the spatial memory domain, stress impairs place learning depending on the hippocampus whereas stimulus-response learning based on the striatum appears to be improved. While the neural basis of this

  20. Stress Induces a Shift Towards Striatum-Dependent Stimulus-Response Learning via the Mineralocorticoid Receptor

    NARCIS (Netherlands)

    Vogel, Susanne; Klumpers, Floris; Schroeder, Tobias Navarro; Oplaat, Krista T.; Krugers, Harm J.; Oitzl, Melly S.; Joels, Marian; Doeller, Christian F.; Fernandez, Guillen

    Stress is assumed to cause a shift from flexible 'cognitive' memory to more rigid 'habit' memory. In the spatial memory domain, stress impairs place learning depending on the hippocampus whereas stimulus-response learning based on the striatum appears to be improved. While the neural basis of this

  1. Effects of different block size distributions in pressure transient response of naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Montazeri, G.H. [Islamic Azad University, Mahshahr (Iran, Islamic Republic of). Dept. of Chemical and Petroleum Engineering], E-mail: montazeri_gh@yahoo.com; Tahami, S.A. [Mad Daneshgostar Tabnak Co. (MDT),Tehran (Iran, Islamic Republic of); Moradi, B.; Safari, E. [Iranian Central Oil Fields Co, Tehran (Iran, Islamic Republic of)], E-mail: morady.babak@gmail.com

    2011-07-15

    This paper presents a model for pressure transient and derivative analysis for naturally fractured reservoirs by a formulation of inter porosity flow incorporating variations in matrix block size, which is inversely related to fracture intensity. Geologically realistic Probability Density Functions (PDFs) of matrix block size, such as uniform, bimodal, linear and exponential distributions, are examined and pseudo-steady-state and transient models for inter porosity flow are assumed. The results have been physically interpreted, and, despite results obtained by other authors, it was found that the shape of pressure derivative curves for different PDFs are basically identical within some ranges of block size variability, inter porosity skin, PDFs parameters and matrix storage capacity. This tool can give an insight on the distribution of block sizes and shapes, together with other sources of information such as Logs and geological observations. (author)

  2. Systemic or Intra-Amygdala Infusion of the Benzodiazepine, Midazolam, Impairs Learning, but Facilitates Re-Learning to Inhibit Fear Responses in Extinction

    Science.gov (United States)

    Hart, Genevra; Harris, Justin A.; Westbrook, R. Frederick

    2010-01-01

    A series of experiments used rats to study the effect of a systemic or intra-amygdala infusion of the benzodiazepine, midazolam, on learning and re-learning to inhibit context conditioned fear (freezing) responses. Rats were subjected to two context-conditioning episodes followed by extinction under drug or vehicle, or to two cycles of context…

  3. Searching for MHz Transients with the VLA Low-band Ionosphere and Transient Experiment (VLITE)

    Science.gov (United States)

    Polisensky, Emil; Peters, Wendy; Giacintucci, Simona; Clarke, Tracy; Kassim, Namir E.; hyman, Scott D.; van der Horst, Alexander; Linford, Justin; Waldron, Zach; Frail, Dale

    2018-01-01

    NRL and NRAO have expanded the low frequency capabilities of the VLA through the VLA Low-band Ionosphere and Transient Experiment (VLITE, http://vlite.nrao.edu/ ), effectively making the instrument two telescopes in one. VLITE is a commensal observing system that harvests data from the prime focus in parallel with normal Cassegrain focus observing on a subset of VLA antennas. VLITE provides over 6000 observing hours per year in a > 5 square degree field-of-view using 64 MHz bandwidth centered on 352 MHz. By operating in parallel, VLITE offers invaluable low frequency data to targeted observations of transient sources detected at higher frequencies. With arcsec resolution and mJy sensitivity, VLITE additionally offers great potential for blind searches of rarer radio-selected transients. We use catalog matching software on the imaging products from the daily astrophysics pipeline and the LOFAR Transients Pipeline (TraP) on repeated observations of the same fields to search for coherent and incoherent astronomical transients on timescales of a few seconds to years. We present the current status of the VLITE transient science program from its initial deployment on 10 antennas in November 2014 through its expansion to 16 antennas in the summer of 2017. Transient limits from VLITE’s first year of operation (Polisensky et al. 2016) are updated per the most recent analysis.

  4. Surprise responses in the human brain demonstrate statistical learning under high concurrent cognitive demand

    Science.gov (United States)

    Garrido, Marta Isabel; Teng, Chee Leong James; Taylor, Jeremy Alexander; Rowe, Elise Genevieve; Mattingley, Jason Brett

    2016-06-01

    The ability to learn about regularities in the environment and to make predictions about future events is fundamental for adaptive behaviour. We have previously shown that people can implicitly encode statistical regularities and detect violations therein, as reflected in neuronal responses to unpredictable events that carry a unique prediction error signature. In the real world, however, learning about regularities will often occur in the context of competing cognitive demands. Here we asked whether learning of statistical regularities is modulated by concurrent cognitive load. We compared electroencephalographic metrics associated with responses to pure-tone sounds with frequencies sampled from narrow or wide Gaussian distributions. We showed that outliers evoked a larger response than those in the centre of the stimulus distribution (i.e., an effect of surprise) and that this difference was greater for physically identical outliers in the narrow than in the broad distribution. These results demonstrate an early neurophysiological marker of the brain's ability to implicitly encode complex statistical structure in the environment. Moreover, we manipulated concurrent cognitive load by having participants perform a visual working memory task while listening to these streams of sounds. We again observed greater prediction error responses in the narrower distribution under both low and high cognitive load. Furthermore, there was no reliable reduction in prediction error magnitude under high-relative to low-cognitive load. Our findings suggest that statistical learning is not a capacity limited process, and that it proceeds automatically even when cognitive resources are taxed by concurrent demands.

  5. Short-term depression and transient memory in sensory cortex.

    Science.gov (United States)

    Gillary, Grant; Heydt, Rüdiger von der; Niebur, Ernst

    2017-12-01

    Persistent neuronal activity is usually studied in the context of short-term memory localized in central cortical areas. Recent studies show that early sensory areas also can have persistent representations of stimuli which emerge quickly (over tens of milliseconds) and decay slowly (over seconds). Traditional positive feedback models cannot explain sensory persistence for at least two reasons: (i) They show attractor dynamics, with transient perturbations resulting in a quasi-permanent change of system state, whereas sensory systems return to the original state after a transient. (ii) As we show, those positive feedback models which decay to baseline lose their persistence when their recurrent connections are subject to short-term depression, a common property of excitatory connections in early sensory areas. Dual time constant network behavior has also been implemented by nonlinear afferents producing a large transient input followed by much smaller steady state input. We show that such networks require unphysiologically large onset transients to produce the rise and decay observed in sensory areas. Our study explores how memory and persistence can be implemented in another model class, derivative feedback networks. We show that these networks can operate with two vastly different time courses, changing their state quickly when new information is coming in but retaining it for a long time, and that these capabilities are robust to short-term depression. Specifically, derivative feedback networks with short-term depression that acts differentially on positive and negative feedback projections are capable of dynamically changing their time constant, thus allowing fast onset and slow decay of responses without requiring unrealistically large input transients.

  6. Mirror neuron activation as a function of explicit learning: changes in mu-event-related power after learning novel responses to ideomotor compatible, partially compatible, and non-compatible stimuli.

    Science.gov (United States)

    Behmer, Lawrence P; Fournier, Lisa R

    2016-11-01

    Questions regarding the malleability of the mirror neuron system (MNS) continue to be debated. MNS activation has been reported when people observe another person performing biological goal-directed behaviors, such as grasping a cup. These findings support the importance of mapping goal-directed biological behavior onto one's motor repertoire as a means of understanding the actions of others. Still, other evidence supports the Associative Sequence Learning (ASL) model which predicts that the MNS responds to a variety of stimuli after sensorimotor learning, not simply biological behavior. MNS activity develops as a consequence of developing stimulus-response associations between a stimulus and its motor outcome. Findings from the ideomotor literature indicate that stimuli that are more ideomotor compatible with a response are accompanied by an increase in response activation compared to less compatible stimuli; however, non-compatible stimuli robustly activate a constituent response after sensorimotor learning. Here, we measured changes in the mu-rhythm, an EEG marker thought to index MNS activity, predicting that stimuli that differ along dimensions of ideomotor compatibility should show changes in mirror neuron activation as participants learn the respective stimulus-response associations. We observed robust mu-suppression for ideomotor-compatible hand actions and partially compatible dot animations prior to learning; however, compatible stimuli showed greater mu-suppression than partially or non-compatible stimuli after explicit learning. Additionally, non-compatible abstract stimuli exceeded baseline only after participants explicitly learned the motor responses associated with the stimuli. We conclude that the empirical differences between the biological and ASL accounts of the MNS can be explained by Ideomotor Theory. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  7. New Learning Methods for Marine Oil Spill Response Training

    Directory of Open Access Journals (Sweden)

    Justiina Halonen

    2017-06-01

    Full Text Available In Finland the Regional Fire and Rescue Services (RFRS are responsible for near shore oil spill response and shoreline cleanup operations. In addition, they assist in other types of maritime incidents, such as search and rescue operations and fire-fighting on board. These statutory assignments require the RFRS to have capability to act both on land and at sea. As maritime incidents occur infrequently, little routine has been established. In order to improve their performance in maritime operations, the RFRS are participating in a new oil spill training programme to be launched by South-Eastern Finland University of Applied Sciences. This training programme aims to utilize new educational methods; e-learning and simulator based training. In addition to fully exploiting the existing navigational bridge simulator, radio communication simulator and crisis management simulator, an entirely new simulator is developed. This simulator is designed to model the oil recovery process; recovery method, rate and volume in various conditions with different oil types. New simulator enables creation of a comprehensive training programme covering training tasks from a distress call to the completion of an oil spill response operation. Structure of the training programme, as well as the training objectives, are based on the findings from competence and education surveys conducted in spring 2016. In these results, a need for vessel maneuvering and navigation exercises together with actual response measures training were emphasized. Also additional training for maritime radio communication, GMDSS-emergency protocols and collaboration with maritime authorities were seemed important. This paper describes new approach to the maritime operations training designed for rescue authorities, a way of learning by doing, without mobilising the vessels at sea.

  8. Modelling and transient simulation of water flow in pipelines using WANDA Transient software

    Directory of Open Access Journals (Sweden)

    P.U. Akpan

    2017-09-01

    Full Text Available Pressure transients in conduits such as pipelines are unsteady flow conditions caused by a sudden change in the flow velocity. These conditions might cause damage to the pipelines and its fittings if the extreme pressure (high or low is experienced within the pipeline. In order to avoid this occurrence, engineers usually carry out pressure transient analysis in the hydraulic design phase of pipeline network systems. Modelling and simulation of transients in pipelines is an acceptable and cost effective method of assessing this problem and finding technical solutions. This research predicts the pressure surge for different flow conditions in two different pipeline systems using WANDA Transient simulation software. Computer models were set-up in WANDA Transient for two different systems namely; the Graze experiment (miniature system and a simple main water riser system based on some initial laboratory data and system parameters. The initial laboratory data and system parameters were used for all the simulations. Results obtained from the computer model simulations compared favourably with the experimental results at Polytropic index of 1.2.

  9. Linear and non-linear dose-response functions reveal a hormetic relationship between stress and learning.

    Science.gov (United States)

    Zoladz, Phillip R; Diamond, David M

    2008-10-16

    Over a century of behavioral research has shown that stress can enhance or impair learning and memory. In the present review, we have explored the complex effects of stress on cognition and propose that they are characterized by linear and non-linear dose-response functions, which together reveal a hormetic relationship between stress and learning. We suggest that stress initially enhances hippocampal function, resulting from amygdala-induced excitation of hippocampal synaptic plasticity, as well as the excitatory effects of several neuromodulators, including corticosteroids, norepinephrine, corticotropin-releasing hormone, acetylcholine and dopamine. We propose that this rapid activation of the amygdala-hippocampus brain memory system results in a linear dose-response relation between emotional strength and memory formation. More prolonged stress, however, leads to an inhibition of hippocampal function, which can be attributed to compensatory cellular responses that protect hippocampal neurons from excitotoxicity. This inhibition of hippocampal functioning in response to prolonged stress is potentially relevant to the well-described curvilinear dose-response relationship between arousal and memory. Our emphasis on the temporal features of stress-brain interactions addresses how stress can activate, as well as impair, hippocampal functioning to produce a hormetic relationship between stress and learning.

  10. RFI flagging implications for short-duration transients

    Science.gov (United States)

    Cendes, Y.; Prasad, P.; Rowlinson, A.; Wijers, R. A. M. J.; Swinbank, J. D.; Law, C. J.; van der Horst, A. J.; Carbone, D.; Broderick, J. W.; Staley, T. D.; Stewart, A. J.; Huizinga, F.; Molenaar, G.; Alexov, A.; Bell, M. E.; Coenen, T.; Corbel, S.; Eislöffel, J.; Fender, R.; Grießmeier, J.-M.; Jonker, P.; Kramer, M.; Kuniyoshi, M.; Pietka, M.; Stappers, B.; Wise, M.; Zarka, P.

    2018-04-01

    With their wide fields of view and often relatively long coverage of any position in the sky in imaging survey mode, modern radio telescopes provide a data stream that is naturally suited to searching for rare transients. However, Radio Frequency Interference (RFI) can show up in the data stream in similar ways to such transients, and thus the normal pre-treatment of filtering RFI (flagging) may also remove astrophysical transients from the data stream before imaging. In this paper we investigate how standard flagging affects the detectability of such transients by examining the case of transient detection in an observing mode used for Low Frequency Array (LOFAR; van Haarlem et al., 2013) surveys. We quantify the fluence range of transients that would be detected, and the reduction of their SNR due to partial flagging. We find that transients with a duration close to the integration sampling time, as well as bright transients with durations on the order of tens of seconds, are completely flagged. For longer transients on the order of several tens of seconds to minutes, the flagging effects are not as severe, although part of the signal is lost. For these transients, we present a modified flagging strategy which mitigates the effect of flagging on transient signals. We also present a script which uses the differences between the two strategies, and known differences between transient RFI and astrophysical transients, to notify the observer when a potential transient is in the data stream.

  11. Transient thermal stresses of work roll by coupled thermoelasticity

    Science.gov (United States)

    Lai, W. B.; Chen, T. C.; Weng, C. I.

    1991-01-01

    A numerical method, based on a two-dimensional plane strain model, is developed to predict the transient responses (that include distributions of temperature, thermal deformation, and thermal stress) of work roll during strip rolling by coupled thermoelasticity. The method consists of discretizing the space domain of the problem by finite element method first, and then treating the time domain by implicit time integration techniques. In order to avoid the difficulty in analysis due to relative movement between work roll and its thermal boundary, the energy equation is formulated with respect to a fixed Eulerian reference frame. The effect of thermoelastic coupling term, that is generally disregarded in strip rolling, can be considered and assessed. The influences of some important process parameters, such as rotational speed of the roll and intensity of heat flux, on transient solutions are also included and discussed. Furthermore, since the stress history at any point of the roll in both transient and steady state could be accurately evaluated, it is available to perform the analysis of thermal fatigue for the roll by means of previous data.

  12. Discovery of 36 eclipsing EL CVn binaries found by the Palomar Transient Factory

    Science.gov (United States)

    van Roestel, J.; Kupfer, T.; Ruiz-Carmona, R.; Groot, P. J.; Prince, T. A.; Burdge, K.; Laher, R.; Shupe, D. L.; Bellm, E.

    2018-04-01

    We report on the discovery and analysis of 36 new eclipsing EL CVn-type binaries, consisting of a core helium-composition pre-white dwarf (pre-He-WD) and an early-type main-sequence companion. This more than doubles the known population of these systems. We have used supervised machine learning methods to search 0.8 million light curves from the Palomar Transient Factory (PTF), combined with Sloan Digital Sky Survey (SDSS), Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and Two-Micron All-Sky Survey (2MASS) colours. The new systems range in orbital periods from 0.46 to 3.8 d and in apparent brightness from ˜14 to 16 mag in the PTF R or g΄ filters. For 12 of the systems, we obtained radial velocity curves with the Intermediate Dispersion Spectrograph at the Isaac Newton Telescope. We modelled the light curves, radial velocity curves and spectral energy distributions to determine the system parameters. The radii (0.3-0.7 R⊙) and effective temperatures (8000-17 000 K) of the pre-He-WDs are consistent with stellar evolution models, but the masses (0.12-0.28 M⊙) show more variance than models have predicted. This study shows that using machine learning techniques on large synoptic survey data is a powerful way to discover substantial samples of binary systems in short-lived evolutionary stages.

  13. An analysis of the transient's social behavior in the radiological emergency planning zone

    International Nuclear Information System (INIS)

    Bang, Sun Young; Lee, Gab Bock; Chung, Yang Geun; Lee, Jae Eun

    2007-01-01

    The purpose of this study is to analyze the social behavior, especially, the evacuation-related social behavior, of the transients in the radiological Emergency Planning Zone (EPZ) of nuclear power plants. So, the meaning and kinds of the evacuation and the significance of the Trip Generation Time (TGT) have been reviewed. The characteristics of the social behavior of the transient around Ulchin, Wolsong and Kori sites was analyzed through field surveys by using the questionnaire. The major findings of this research implications are as follows. First, for securing the safe evacuation, the alternatives to effectively provide the information on the evacuation warning may be prepared. Second, it is necessary to establish the education and training of transient's evacuation. Third, it is needed that the cause and background of the evacuation refusal are identified and the new response plan to secure transient's safety is prepared

  14. Transient regional climate change: analysis of the summer climate response in a high-resolution, century-scale, ensemble experiment over the continental United States

    Science.gov (United States)

    Diffenbaugh, Noah S.; Ashfaq, Moetasim; Scherer, Martin

    2013-01-01

    Integrating the potential for climate change impacts into policy and planning decisions requires quantification of the emergence of sub-regional climate changes that could occur in response to transient changes in global radiative forcing. Here we report results from a high-resolution, century-scale, ensemble simulation of climate in the United States, forced by atmospheric constituent concentrations from the Special Report on Emissions Scenarios (SRES) A1B scenario. We find that 21st century summer warming permanently emerges beyond the baseline decadal-scale variability prior to 2020 over most areas of the continental U.S. Permanent emergence beyond the baseline annual-scale variability shows much greater spatial heterogeneity, with emergence occurring prior to 2030 over areas of the southwestern U.S., but not prior to the end of the 21st century over much of the southcentral and southeastern U.S. The pattern of emergence of robust summer warming contrasts with the pattern of summer warming magnitude, which is greatest over the central U.S. and smallest over the western U.S. In addition to stronger warming, the central U.S. also exhibits stronger coupling of changes in surface air temperature, precipitation, and moisture and energy fluxes, along with changes in atmospheric circulation towards increased anticylonic anomalies in the mid-troposphere and a poleward shift in the mid-latitude jet aloft. However, as a fraction of the baseline variability, the transient warming over the central U.S. is smaller than the warming over the southwestern or northeastern U.S., delaying the emergence of the warming signal over the central U.S. Our comparisons with observations and the Coupled Model Intercomparison Project Phase 3 (CMIP3) ensemble of global climate model experiments suggest that near-term global warming is likely to cause robust sub-regional-scale warming over areas that exhibit relatively little baseline variability. In contrast, where there is greater

  15. Transient current in a quantum dot subject to a change in coupling to its leads

    International Nuclear Information System (INIS)

    Izmaylov, A F; Goker, A; Friedman, B A; Nordlander, P

    2006-01-01

    The time-dependent non-crossing approximation is used to calculate the transient currents through a quantum dot in the Kondo regime subject to a sudden change in its coupling to the leads. The currents are found to display transient non-universal behaviour immediately after the perturbation and then to follow a slow universal increase toward equilibrium. The timescales for the approach to equilibrium are shown to be the same as those recently identified in a study of transient currents in a quantum dot subject to a sudden change in the energy of the dot level (Plihal et al 2005 Phys. Rev. B 71 165321). We present improved numerical algorithms which enable relatively fast calculation of the transient response of quantum dots to sudden perturbations

  16. Transient thermal hydraulic modeling and analysis of ITER divertor plate system

    International Nuclear Information System (INIS)

    El-Morshedy, Salah El-Din; Hassanein, Ahmed

    2009-01-01

    A mathematical model has been developed/updated to simulate the steady state and transient thermal-hydraulics of the International Thermonuclear Experimental Reactor (ITER) divertor module. The model predicts the thermal response of the armour coating, divertor plate structural materials and coolant channels. The selected heat transfer correlations cover all operating conditions of ITER under both normal and off-normal situations. The model also accounts for the melting, vaporization, and solidification of the armour material. The developed model is to provide a quick benchmark of the HEIGHTS multidimensional comprehensive simulation package. The present model divides the coolant channels into a specified axial regions and the divertor plate into a specified radial zones, then a two-dimensional heat conduction calculation is created to predict the temperature distribution for both steady and transient states. The model is benchmarked against experimental data performed at Sandia National Laboratory for both bare and swirl tape coolant channel mockups. The results show very good agreements with the data for steady and transient states. The model is then used to predict the thermal behavior of the ITER plasma facing and structural materials due to plasma instability event where 60 MJ/m 2 plasma energy is deposited over 500 ms. The results for ITER divertor response is analyzed and compared with HEIGHTS results.

  17. Transient thermal hydraulic modeling and analysis of ITER divertor plate system

    Energy Technology Data Exchange (ETDEWEB)

    El-Morshedy, Salah El-Din [Argonne National Laboratory, Argonne, IL (United States); Atomic Energy Authority, Cairo (Egypt)], E-mail: selmorshedy@etrr2-aea.org.eg; Hassanein, Ahmed [Purdue University, West Lafayette, IN (United States)], E-mail: hassanein@purdue.edu

    2009-12-15

    A mathematical model has been developed/updated to simulate the steady state and transient thermal-hydraulics of the International Thermonuclear Experimental Reactor (ITER) divertor module. The model predicts the thermal response of the armour coating, divertor plate structural materials and coolant channels. The selected heat transfer correlations cover all operating conditions of ITER under both normal and off-normal situations. The model also accounts for the melting, vaporization, and solidification of the armour material. The developed model is to provide a quick benchmark of the HEIGHTS multidimensional comprehensive simulation package. The present model divides the coolant channels into a specified axial regions and the divertor plate into a specified radial zones, then a two-dimensional heat conduction calculation is created to predict the temperature distribution for both steady and transient states. The model is benchmarked against experimental data performed at Sandia National Laboratory for both bare and swirl tape coolant channel mockups. The results show very good agreements with the data for steady and transient states. The model is then used to predict the thermal behavior of the ITER plasma facing and structural materials due to plasma instability event where 60 MJ/m{sup 2} plasma energy is deposited over 500 ms. The results for ITER divertor response is analyzed and compared with HEIGHTS results.

  18. EEG transients in the sigma range during non-REM sleep predict learning in dogs

    NARCIS (Netherlands)

    Iotchev, I.B.; Kis, A.; Bodizs, R.; Luijtelaar, E.L.J.M. van; Kubinyi, E.

    2017-01-01

    Sleep spindles are phasic bursts of thalamo-cortical activity, visible in the cortex as transient oscillations in the sigma range (usually defined in humans as 12-14 or 9-16 Hz). They have been associated with sleep-dependent memory consolidation and sleep stability in humans and rodents.

  19. Transient expression of protein tyrosine phosphatases encoded in Cotesia plutellae bracovirus inhibits insect cellular immune responses

    Science.gov (United States)

    Ibrahim, Ahmed M. A.; Kim, Yonggyun

    2008-01-01

    Several immunosuppressive factors are associated with parasitism of an endoparasitoid wasp, Cotesia plutellae, on the diamondback moth, Plutella xylostella. C. plutellae bracovirus (CpBV) encodes a large number of putative protein tyrosine phosphatases (PTPs), which may play a role in inhibiting host cellular immunity. To address this inhibitory hypothesis of CpBV-PTPs, we performed transient expression of individual CpBV-PTPs in hemocytes of the beet armyworm, Spodoptera exigua, and analyzed their cellular immune responses. Two different forms of CpBV-PTPs were chosen and cloned into a eukaryotic expression vector under the control of the p10 promoter of baculovirus: one with the normal cysteine active site (CpBV-PTP1) and the other with a mutated active site (CpBV-PTP5). The hemocytes transfected with CpBV-PTP1 significantly increased in PTP activity compared to control hemocytes, but those with CpBV-PTP5 exhibited a significant decrease in the PTP activity. All transfected hemocytes exhibited a significant reduction in both cell spreading and encapsulation activities compared to control hemocytes. Co-transfection of CpBV-PTP1 together with its double-stranded RNA reduced the messenger RNA (mRNA) level of CpBV-PTP1 and resulted in recovery of both hemocyte behaviors. This is the first report demonstrating that the polydnaviral PTPs can manipulate PTP activity of the hemocytes to interrupt cellular immune responses.

  20. Machine learning for predicting the response of breast cancer to neoadjuvant chemotherapy.

    Science.gov (United States)

    Mani, Subramani; Chen, Yukun; Li, Xia; Arlinghaus, Lori; Chakravarthy, A Bapsi; Abramson, Vandana; Bhave, Sandeep R; Levy, Mia A; Xu, Hua; Yankeelov, Thomas E

    2013-01-01

    To employ machine learning methods to predict the eventual therapeutic response of breast cancer patients after a single cycle of neoadjuvant chemotherapy (NAC). Quantitative dynamic contrast-enhanced MRI and diffusion-weighted MRI data were acquired on 28 patients before and after one cycle of NAC. A total of 118 semiquantitative and quantitative parameters were derived from these data and combined with 11 clinical variables. We used Bayesian logistic regression in combination with feature selection using a machine learning framework for predictive model building. The best predictive models using feature selection obtained an area under the curve of 0.86 and an accuracy of 0.86, with a sensitivity of 0.88 and a specificity of 0.82. With the numerous options for NAC available, development of a method to predict response early in the course of therapy is needed. Unfortunately, by the time most patients are found not to be responding, their disease may no longer be surgically resectable, and this situation could be avoided by the development of techniques to assess response earlier in the treatment regimen. The method outlined here is one possible solution to this important clinical problem. Predictive modeling approaches based on machine learning using readily available clinical and quantitative MRI data show promise in distinguishing breast cancer responders from non-responders after the first cycle of NAC.

  1. Pulse mitigation and heat transfer enhancement techniques. Volume 3: Liquid sodium heat transfer facility and transient response of sodium heat pipe to pulse forward and reverse heat load

    Science.gov (United States)

    Chow, L. C.; Hahn, O. J.; Nguyen, H. X.

    1992-08-01

    This report presents the description of a liquid sodium heat transfer facility (sodium loop) constructed to support the study of transient response of heat pipes. The facility, consisting of the loop itself, a safety system, and a data acquisition system, can be safely operated over a wide range of temperature and sodium flow rate. The transient response of a heat pipe to pulse heat load at the condenser section was experimentally investigated. A 0.457 m screen wick, sodium heat pipe with an outer diameter of 0.127 m was tested under different heat loading conditions. A major finding was that the heat pipe reversed under a pulse heat load applied at the condenser. The time of reversal was approximately 15 to 25 seconds. The startup of the heat pipe from frozen state was also studied. It was found that during the startup process, at least part of the heat pipe was active. The active region extended gradually down to the end of the condenser until all of the working fluid in the heat pipe was molten.

  2. Individual response technology to promote active learning within the caring sciences: An experimental research study.

    Science.gov (United States)

    Hedén, Lena; Ahlstrom, Linda

    2016-01-01

    One major challenge in delivering lectures to large and diverse classes is the maintenance of a high standard of lecturing in order to engage students and increase their participation and involvement. The lecturer's assignment is to arrange and prepare the lecture before teaching, hence enabling students' enhanced learning. Individual response technology could encourage students' active learning and activate higher cognitive levels. The aim of this study was to evaluate individual response technology as a complement during lectures for students in higher education, in terms of the students' experiences of participation, engagement, and active learning. Also of interest was whether this technology can be considered a supportive technical system. Data were collected through a questionnaire where levels of each condition were reported on a numeric rating scale (0-10) at baseline and after the introduction of individual response technology. To get a broader perspective, two types of lectures (pediatric and statistical) were included, giving a total of four assessment times. The participants comprised 59 students in Bachelor of Nursing program at a Swedish metropolitan university. Overall, when individual response technology was used, students reported increased experience of engagement (n=82, mean 6.1 vs. n=65, mean 7.3, pactive learning (n=92, mean 7.3 vs. n=79, mean 8.2 plearning within the caring sciences. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. CONTEMPT/LT-028 Browns Ferry studies of an anticipated transient without scram

    International Nuclear Information System (INIS)

    Holcomb, E.E.

    1983-01-01

    The Browns Ferry Nuclear Plant containment response during the first 30 min of an anticipated transient without scram (ATWS) is the subject of this paper. Three cases, each initiated by a main steam isolation valve closure, are presented: the ATWS is mitigated by operator actions in the spirit of the General Electric Emergency Procedure Guidelines; the ATWS is managed by the plant automatic control systems; and the ATWS proceeds as in first case except that the drywell coolers are unavailable. Success of the standby liquid control system is assumed in the last two transients

  4. Transients drive the demographic dynamics of plant populations in variable environments

    DEFF Research Database (Denmark)

    McDonald, Jenni L; Stott, Iain; Townley, Stuart

    2016-01-01

    clear patterns related to growth form. We find a surprising tendency for plant populations to boom rather than bust in response to temporal changes in vital rates and that stochastic growth rates increase with increasing tendency to boom. Synthesis. Transient dynamics contribute significantly...

  5. MHD aspects of coronal transients

    International Nuclear Information System (INIS)

    Anzer, U.

    1979-10-01

    If one defines coronal transients as events which occur in the solar corona on rapid time scales (< approx. several hours) then one would have to include a large variety of solar phenomena: flares, sprays, erupting prominences, X-ray transients, white light transients, etc. Here we shall focus our attention on the latter two phenomena. (orig.) 891 WL/orig. 892 RDG

  6. Interpersonal social responsibility model of service learning: A longitudinal study.

    Science.gov (United States)

    Lahav, Orit; Daniely, Noa; Yalon-Chamovitz, Shira

    2018-01-01

    Service-learning (SL) is commonly used in Occupational Therapy (OT) programs worldwide as a community placement educational strategy. However, most SL models are not clearly defined in terms of both methodology and learning outcomes. This longitudinal study explores a structured model of Service-Learning (Interpersonal Social Responsibility-Service Learning: ISR-SL) aimed towards the development of professional identity among OT students. Based on OT students experiences from the end of the course through later stages as mature students and professionals. A qualitative research design was used to explore the perceptions and experiences of 150 first, second, and third-year OT students and graduates who have participated in ISR-SL during their first academic year. Our findings suggest that the structured, long-term relationship with a person with a disability in the natural environment, which is the core of the ISR-SL, allowed students to develop a professional identity based on seeing the person as a whole and recognizing his/her centrality in the therapeutic relationship. This study suggests ISR-SL as future direction or next step for implementing SL in OT and other healthcare disciplines programs.

  7. Learning to Learn.

    Science.gov (United States)

    Weiss, Helen; Weiss, Martin

    1988-01-01

    The article reviews theories of learning (e.g., stimulus-response, trial and error, operant conditioning, cognitive), considers the role of motivation, and summarizes nine research-supported rules of effective learning. Suggestions are applied to teaching learning strategies to learning-disabled students. (DB)

  8. Analysis of a high pressure ATWS [anticipated transient without scram] with very low make-up flow

    International Nuclear Information System (INIS)

    Wagner, K.C.

    1988-10-01

    A series of calculations were performed to analyze the response of General Electric Company's (GE) advanced boiling water reactor (ABWR) during an anticipated transient without scram (ATWS). This work investigated the early plant response with an assumed failure or manual inhibit of the high pressure core flooder (HPCF). Consequently, the reactor core isolation cooling (RCIC) and control rod drive (CRD) systems are the only sources of high pressure injection available to maintain core cooling. Steam leaving the reactor pressure vessel was diverted to the pressure suppression pool (PSP) via the steam line and the safety relief valves. The combination of an unscrammed core and the CRD and RCIC injection sources make this a particularly challenging transient. System energy balance calculations were performed to predict the core power and PSP heat-up rate. The amount of vessel vapor superheat and the PSP temperature were found to significantly affect the resultant core power. Consequently, detailed thermal-hydraulic calculations were performed to simulate the system response during the postulated transient. 15 refs., 15 figs., 4 tabs

  9. The influence of tyre transient side force properties on vehicle lateral acceleration for a time-varying vertical force

    Science.gov (United States)

    Takahashi, Toshimichi

    2018-05-01

    The tyre model which formerly developed by the author et al. and describes the tyre transient responses of side force and aligning moment under the time-varying vertical force was implemented to the vehicle dynamics simulation software and the influence of tyre side force transient property on the vehicle behaviour was investigated. The vehicle responses with/without tyre transient property on sinusoidally undulated road surfaces were simulated and compared. It was found that the average lateral acceleration of the vehicle at the sinusoidal steering wheel angle input decreases on the undulated road of long wavelength (3 m) for both cases, but when the wavelength becomes shorter (1 m), the average lateral acceleration increases only in the case that the transient property is considered. The cause of those changes is explained by using the tyre-related variables. Also the steady-state turning behaviour of the vehicle on undulated roads are shown and discussed.

  10. Teaching parents about responsive feeding through a vicarious learning video: A pilot randomized controlled trial

    Science.gov (United States)

    The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using com...

  11. Student Responses Toward Student Worksheets Based on Discovery Learning for Students with Intrapersonal and Interpersonal Intelligence

    Science.gov (United States)

    Yerizon, Y.; Putra, A. A.; Subhan, M.

    2018-04-01

    Students have a low mathematical ability because they are used to learning to hear the teacher's explanation. For that students are given activities to sharpen his ability in math. One way to do that is to create discovery learning based work sheet. The development of this worksheet took into account specific student learning styles including in schools that have classified students based on multiple intelligences. The dominant learning styles in the classroom were intrapersonal and interpersonal. The purpose of this study was to discover students’ responses to the mathematics work sheets of the junior high school with a discovery learning approach suitable for students with Intrapersonal and Interpersonal Intelligence. This tool was developed using a development model adapted from the Plomp model. The development process of this tools consists of 3 phases: front-end analysis/preliminary research, development/prototype phase and assessment phase. From the results of the research, it is found that students have good response to the resulting work sheet. The worksheet was understood well by students and its helps student in understanding the concept learned.

  12. Transient Response in Monolithic Mach-Zehnder Optical Modulator Using (Ba,Sr)TiO3 Film Sputtered at Low Temperature on Silicon

    Science.gov (United States)

    Suzuki, Masato; Nagata, Kazuma; Tanushi, Yuichiro; Yokoyama, Shin

    2007-04-01

    We have fabricated Mach-Zhender interferometers (MZIs) using the (Ba,Sr)TiO3 (BST) film sputter-deposited at 450 °C, which is a critical temperature for the process after metallization. An optical modulation of about 10% is achieved when 200 V is applied (electric field in BST is 1.2× 104 V/cm). However, the response time of optical modulation to step function voltage is slow (1.0-6.3 s). We propose a model for the slow transient behavior based on movable ions and a long dielectric relaxation time for the BST film, and good qualitative agreement is obtained with experimental results.

  13. On-Line, Self-Learning, Predictive Tool for Determining Payload Thermal Response

    Science.gov (United States)

    Jen, Chian-Li; Tilwick, Leon

    2000-01-01

    This paper will present the results of a joint ManTech / Goddard R&D effort, currently under way, to develop and test a computer based, on-line, predictive simulation model for use by facility operators to predict the thermal response of a payload during thermal vacuum testing. Thermal response was identified as an area that could benefit from the algorithms developed by Dr. Jeri for complex computer simulations. Most thermal vacuum test setups are unique since no two payloads have the same thermal properties. This requires that the operators depend on their past experiences to conduct the test which requires time for them to learn how the payload responds while at the same time limiting any risk of exceeding hot or cold temperature limits. The predictive tool being developed is intended to be used with the new Thermal Vacuum Data System (TVDS) developed at Goddard for the Thermal Vacuum Test Operations group. This model can learn the thermal response of the payload by reading a few data points from the TVDS, accepting the payload's current temperature as the initial condition for prediction. The model can then be used as a predictive tool to estimate the future payload temperatures according to a predetermined shroud temperature profile. If the error of prediction is too big, the model can be asked to re-learn the new situation on-line in real-time and give a new prediction. Based on some preliminary tests, we feel this predictive model can forecast the payload temperature of the entire test cycle within 5 degrees Celsius after it has learned 3 times during the beginning of the test. The tool will allow the operator to play "what-if' experiments to decide what is his best shroud temperature set-point control strategy. This tool will save money by minimizing guess work and optimizing transitions as well as making the testing process safer and easier to conduct.

  14. Analysis of core uncovery time in Kuosheng station blackout transient with MELCOR

    International Nuclear Information System (INIS)

    Wang, S.J.; Chien, C.S.

    1996-01-01

    The MELCOR code, developed by the Sandia National Laboratories, is capable of simulating severe accident phenomena of nuclear power plants. Core uncovery time is an important parameter in the probabilistic risk assessment. However, many MELCOR users do not generate the initial conditions in a station blackout (SBO) transient analysis. Thus, achieving reliable core uncovery time is difficult. The core uncovery time for the Kuosheng nuclear power plant during an SBO transient is analyzed. First, full-power steady-state conditions are generated with the application of a developed self-initialization algorithm. Then the response of the SBO transient up to core uncovery is simulated. The effects of key parameters including the initialization process and the reactor feed pump (RFP) coastdown time on the core uncovery time are analyzed. The initialization process is the most important parameter that affects the core uncovery time. Because SBO transient analysis, the correct initial conditions must be generated to achieve a reliable core uncovery time. The core uncovery time is also sensitive to the RFP coastdown time. A correct time constant is required

  15. Transient-Switch-Signal Suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.

  16. Summary of transient analysis

    International Nuclear Information System (INIS)

    Saha, P.

    1984-01-01

    This chapter reviews the papers on the pressurized water reactor (PWR) and boiling water reactor (BWR) transient analyses given at the American Nuclear Society Topical Meeting on Anticipated and Abnormal Plant Transients in Light Water Reactors. Most of the papers were based on the systems calculations performed using the TRAC-PWR, RELAP5 and RETRAN codes. The status of the nuclear industry in the code applications area is discussed. It is concluded that even though comprehensive computer codes are available for plant transient analysis, there is still a need to exercise engineering judgment, simpler tools and even hand calculations to supplement these codes

  17. Criticality meets learning: Criticality signatures in a self-organizing recurrent neural network.

    Science.gov (United States)

    Del Papa, Bruno; Priesemann, Viola; Triesch, Jochen

    2017-01-01

    Many experiments have suggested that the brain operates close to a critical state, based on signatures of criticality such as power-law distributed neuronal avalanches. In neural network models, criticality is a dynamical state that maximizes information processing capacities, e.g. sensitivity to input, dynamical range and storage capacity, which makes it a favorable candidate state for brain function. Although models that self-organize towards a critical state have been proposed, the relation between criticality signatures and learning is still unclear. Here, we investigate signatures of criticality in a self-organizing recurrent neural network (SORN). Investigating criticality in the SORN is of particular interest because it has not been developed to show criticality. Instead, the SORN has been shown to exhibit spatio-temporal pattern learning through a combination of neural plasticity mechanisms and it reproduces a number of biological findings on neural variability and the statistics and fluctuations of synaptic efficacies. We show that, after a transient, the SORN spontaneously self-organizes into a dynamical state that shows criticality signatures comparable to those found in experiments. The plasticity mechanisms are necessary to attain that dynamical state, but not to maintain it. Furthermore, onset of external input transiently changes the slope of the avalanche distributions - matching recent experimental findings. Interestingly, the membrane noise level necessary for the occurrence of the criticality signatures reduces the model's performance in simple learning tasks. Overall, our work shows that the biologically inspired plasticity and homeostasis mechanisms responsible for the SORN's spatio-temporal learning abilities can give rise to criticality signatures in its activity when driven by random input, but these break down under the structured input of short repeating sequences.

  18. Learning from Katrina: environmental health observations from the SWCPHP response team in Houston.

    Science.gov (United States)

    Elledge, Brenda L; Boatright, Daniel T; Woodson, Paul; Clinkenbeard, Rodney E; Brand, Michael W

    2007-09-01

    Hurricane Katrina provided an opportunity to observe the public health and medical care response system in practice and provided vital lessons about identifying and learning critical response measures as well as about ineffective investments of time and effort. The Southwest Center for Public Health Preparedness (SWCPHP) response team, while working among evacuees housed at Reliant Park in Houston, Texas, made a number of observations related to environmental public health. This summary reports firsthand observations which are, to a great extent, supported by the Federal Response to Hurricane Katrina: Lessons Learned report, and it provides a contextual backdrop for improvement in the areas of volunteer and citizen preparedness training and education. Katrina provided an opportunity to see public health in a highly stressed practice setting and to identify and reinforce the fundamental tenets of public health with which all individuals responding to an event should be familiar. Knowledge gained from Katrina should be integrated into future efforts related to disaster response planning; specifically, it is imperative that volunteers receive standardized training in the areas of incident command systems (ICS), basic hygiene, transmission of disease, and food and water safety principles.

  19. Experience with transients in German NPPs

    International Nuclear Information System (INIS)

    Lindauer, E.

    1984-01-01

    This chapter examines reactor accidents in the Federal Republic of Germany based on the formal reporting system for licensee event reports (LERs) and a special investigation on all unplanned power variations in 3 PWRs. The significant transients experienced by BWR type reactors are analyzed. The main goal is to find weak points which caused the transient or influenced its course in an unfavorable way in order to improve the affected plant and others. The complete survey of all transients, with normally little or no safety relevance, allows statistical evaluations and the analysis of trends. It is concluded that significant transients were mainly experienced at older plants, whereas plants of an advanced design produced very few significant transients. The most frequent human errors which lead to transients are failure search in electronic systems and errors during design and commissioning

  20. Transient Performance of a Vertical Axis Wind Turbine

    Science.gov (United States)

    Onol, Aykut; Yesilyurt, Serhat

    2016-11-01

    A coupled CFD/rotor dynamics modeling approach is presented for the analysis of realistic transient behavior of a height-normalized, three-straight-bladed VAWT subject to inertial effects of the rotor and generator load which is manipulated by a feedback control under standardized wind gusts. The model employs the k- ɛ turbulence model to approximate unsteady Reynolds-averaged Navier-Stokes equations and is validated with data from field measurements. As distinct from related studies, here, the angular velocity is calculated from the rotor's equation of motion; thus, the dynamic response of the rotor is taken into account. Results include the following: First, the rotor's inertia filters large amplitude oscillations in the wind torque owing to the first-order dynamics. Second, the generator and wind torques differ especially during wind transients subject to the conservation of angular momentum of the rotor. Third, oscillations of the power coefficient exceed the Betz limit temporarily due to the energy storage in the rotor, which acts as a temporary buffer that stores the kinetic energy like a flywheel in short durations. Last, average of transient power coefficients peaks at a smaller tip-speed ratio for wind gusts than steady winds. This work was supported by the Sabanci University Internal Research Grant Program (SU-IRG-985).

  1. Influence of Base Oil Polarity on the Transient Shear Flow of Biodegradable Lubricating Greases

    Directory of Open Access Journals (Sweden)

    Martin Fiedler

    2015-09-01

    Full Text Available The scope of this study is to elucidate the physical mechanisms influencing the transient flow behavior of lubricating greases based on biogenic oleochemicals from a polarity point of view. This includes the mutually interacting influence of base oil polarity and thickening agents on the rheologically-measured mechanical structural degradation in transient shear flow. Due to the high temperature dependence of Keesom forces in the background of polar-active bond mechanisms, the analysis of the transient flow response as a function of temperature allows to attribute the observed influences to differences in base oil polarity. In general, clay-thickened greases show a greater tendency to be rheologically influenced by base oil polarities than soap-thickened lubricating greases.

  2. Nuclear power plant transients: where are we

    International Nuclear Information System (INIS)

    Majumdar, D.

    1984-05-01

    This document is in part a postconference review and summary of the American Nuclear Society sponsored Anticipated and Abnormal Plant Transients in Light Water Reactors Conference held in Jackson, Wyoming, September 26-29, 1983, and in part a reflection upon the issues of plant transients and their impact on the viability of nuclear power. This document discusses state-of-the-art knowledge, deficiencies, and future directions in the plant transients area as seen through this conference. It describes briefly what was reported in this conference, emphasizes areas where it is felt there is confidence in the nuclear industry, and also discusses where the experts did not have a consensus. Areas covered in the document include major issues in operational transients, transient management, transient events experience base, the status of the analytical tools and their capabilities, probabilistic risk assessment applications in operational transients, and human factors impact on plant transients management

  3. EP1000 anticipated transient without scram analyses

    International Nuclear Information System (INIS)

    Saiu, G.; Frogheri, M.; Schulz, T.L.

    2001-01-01

    The present paper summarizes the main results of the Anticipated Transient Without Scram (ATWS) analysis activity, performed for the European Passive Plant Program (EPP). The behavior of the EP1000 plant following an ATWS has been analyzed by means of the RELAP5/Mod3.2 code. An ATWS is defined as an Anticipated Transient accompanied by a common mode failure in the reactor protection system, such that the control rods do not scram as required to mitigate the consequences of the transient. According to the experience gained in PWR design, the limiting ATWS events, in a PWR, have been found to be the heatup transients caused by a reduction of heat removal capability by the secondary side of the plant. For this reason, the Loss of Normal Feedwater initiating event, to which the failure of the reactor scram is associated, has been analyzed. The purpose of the study is to verify the performance requirements set for the core feedback characteristics (that is to evaluate the effect of the low boron core neutron kinetic parameters), the overpressure protection system, and boration systems to cope with the EUR Acceptance Criteria for ATWS. Another purpose of this analysis was to support development of revised PSA success criteria that would reduce the contribution of ATWS to the large release frequency (LRF). The low boron core improved the basic EP1000 response to an ATWS event. In particular, the peak pressure was significantly lower than that which would result from a standard core configuration. The improved ATWS analysis results also permitted improved ATWS PSA success criteria. For example, the reduced peak pressure allows the use of other plant features to mitigate the event, including manual initiation of feed-bleed cooling in the event of PRHR HX failure. As a result, the core melt frequency and especially the LRF are significantly reduced. (author)

  4. Transient Monitoring Function–Based Fault Detection for Inverter-Interfaced Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Mehrizi-Sani, Ali

    2018-01-01

    One of the major challenges in protection of the inverter-interfaced islanded microgrids is their limited fault current level. This degrades the performance of traditional overcurrent protection schemes. This paper proposes a fault detection strategy based on monitoring the transient response......-domain simulation case studies using the CIGRE benchmark low voltage microgrid network....

  5. Transient osteoporosis of the hip

    International Nuclear Information System (INIS)

    McWalter, Patricia; Hassan Ahmed

    2007-01-01

    Transient osteoporosis of the hip is an uncommon cause of hip pain, mostly affecting healthy middle-aged men and also women in the third trimester of pregnancy. We present a case of transient osteoporosis of the hip in a 33-year-old non-pregnant female patient. This case highlights the importance of considering a diagnosis of transient osteoporosis of the hip in patients who present with hip pain. (author)

  6. Optimal and Learning-Based Demand Response Mechanism for Electric Water Heater System

    Directory of Open Access Journals (Sweden)

    Bo Lin

    2017-10-01

    Full Text Available This paper investigates how to develop a learning-based demand response approach for electric water heater in a smart home that can minimize the energy cost of the water heater while meeting the comfort requirements of energy consumers. First, a learning-based, data-driven model of an electric water heater is developed by using a nonlinear autoregressive network with external input (NARX using neural network. The model is updated daily so that it can more accurately capture the actual thermal dynamic characteristics of the water heater especially in real-life conditions. Then, an optimization problem, based on the NARX water heater model, is formulated to optimize energy management of the water heater in a day-ahead, dynamic electricity price framework. A genetic algorithm is proposed in order to solve the optimization problem more efficiently. MATLAB (R2016a is used to evaluate the proposed learning-based demand response approach through a computational experiment strategy. The proposed approach is compared with conventional method for operation of an electric water heater. Cost saving and benefits of the proposed water heater energy management strategy are explored.

  7. A 3 A sink/source current fast transient response low-dropout G{sub m} driven linear regulator

    Energy Technology Data Exchange (ETDEWEB)

    Chu Xiuqin; Li Qingwei; Lai Xinquan; Yuan Bing [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China); Li Yanming [School of Electronic and Control Engineering, Chang' an University, Xi' an 710064 (China); Zhao Yongrui, E-mail: liqw309@163.com, E-mail: xqchu@mail.xidian.edu.cn [Key Laboratory of High-Speed Circuit Design and EMC, Ministry of Education, Xidian University, Xi' an 710071 (China)

    2011-06-15

    A 3 A sink/source G{sub m}-driven CMOS low-dropout regulator (LDO), specially designed for low input voltage and low cost, is presented by utilizing the structure of a current mirror G{sub m} (transconductance) driving technique, which provides high stability as well as a fast load transient response. The proposed LDO was fabricated by a 0.5 {mu}m standard CMOS process, and the die size is as small as 1.0 mm{sup 2}. The proposed LDO dissipates 220 {mu}A of quiescent current in no-load conditions and is able to deliver up to 3 A of load current. The measured results show that the output voltage can be resumed within 2 {mu}s with a less than 1 mV overshoot and undershoot in the output current step from -1.8 to 1.8 A with a 0.1 {mu}s rising and falling time at three 10 {mu}F ceramic capacitors. (semiconductor integrated circuits)

  8. Transient Simulation of Wind Turbine Towers under Lightning Stroke

    Directory of Open Access Journals (Sweden)

    Xiaoqing Zhang

    2013-01-01

    Full Text Available A simulation algorithm is proposed in this paper for lightning transient analysis of the wind turbine (WT towers. In the proposed algorithm, the tower body is first subdivided into a discrete multiconductor system. A set of formulas are given to calculate the electrical parameters of the branches in the multiconductor system. By means of the electrical parameters, each branch unit in the multiconductor system is replaced as a coupled π-type circuit and the multiconductor system is converted into a circuit model. Then, the lightning transient responses can be obtained in different parts on the tower body by solving the circuit equations of the equivalent discretization network. The laboratory measurement is also made by a reduced-scale tower for checking the validity of the proposed algorithm.

  9. Loss-of-flow transient characterization in carbide-fueled LMFBRs

    International Nuclear Information System (INIS)

    Rothrock, R.B.; Morgan, M.M.; Baars, R.E.; Elson, J.S.; Wray, M.L.

    1985-01-01

    One of the benefits derived from the use of carbide fuel in advanced Liquid Metal Fast Breeder Reactors (LMFBRs) is a decreased vulnerability to certain accidents. This can be achieved through the combination of advanced fuel performance with the enhanced reactivity feedback effects and passive shutdown cooling systems characteristic of the current 'inherently safe' plant concepts. The calculated core response to an unprotected loss of flow (ULOF) accident has frequently been used as a benchmark test of these designs, and the advantages of a high-conductivity fuel in relation to this type of transient have been noted in previous analyses. To evaluate this benefit in carbide-fueled LMFBRs incorporating representative current plant design features, limited calculations have been made of a ULOF transient in a small ('modular') carbide-fueled LMFBR

  10. How Do School Librarians Perceive Dispositions for Learning and Social Responsibility?

    Science.gov (United States)

    Arnone, Marilyn

    2010-01-01

    This article discusses the implication of the study involving school librarians regarding how they perceive dispositions for learning and social responsibility. It also presents descriptive results of the most common areas discussed by participants, and provides anecdotal data from the transcripts and some subjective impressions of the researcher.…

  11. Transient Performance Improvement Circuit (TPIC)s for DC-DC converter applications

    Science.gov (United States)

    Lim, Sungkeun

    Gordon Moore famously predicted the exponential increase in transistor integration and computing power that has been witnessed in recent decades [1]. In the near future, it is expected that more than one billion transistors will be integrated per chip, and advanced microprocessors will require clock speeds in excess of several GHz. The increasing number of transistors and high clock speeds will necessitate the consumption of more power. By 2014, it is expected that the maximum power consumption of the microprocessor will reach approximately 150W, and the maximum load current will be around 150A. Today's trend in power and thermal management is to reduce supply voltage as low as possible to reduce delivered power. It is anticipated that the Intel cores will operate on 0.8V of supply voltage by 2014 [2]. A significant challenge in Voltage Regulator Module (VRM) development for next generation microprocessors is to regulate the supply voltage within a certain tolerance band during high slew rate load transitions, since the required supply voltage tolerance band will be much narrower than the current requirement. If VR output impedance is maintained at a constant value from DC to high frequency, large output voltage spikes can be avoided during load cur- rent transients. Based on this, the Adaptive Voltage Position (AVP) concept was developed to achieve constant VR output impedance to improve transient response performance [3]. However, the VR output impedance can not be made constant over the entire frequency range with AVP design, because the AVP design makes the VR output impedance constant only at low frequencies. To make the output impedance constant at high frequencies, many bulk capacitors and ceramic capacitors are required. The tight supply voltage tolerance for the next generation of microprocessors during high slew rate load transitions requires fast transient response power supplies. A VRM can not follow the high slew rate load current transients, because

  12. A COMETHE version with transient capability

    International Nuclear Information System (INIS)

    Vliet, J. van; Lebon, G.; Mathieu, P.

    1980-01-01

    A version of the COMETHE code is under development to simulate transient situations. This paper focuses on some aspects of the transient heat transfer models. Initially the coupling between transient heat transfer and other thermomechanical models is discussed. An estimation of the thermal characteristic times shows that the cladding temperatures are often in quasi-steady state. In order to reduce the computing time, calculations are therefore switched from a transient to a quasi-static numerical procedure as soon as such a quasi-equilibrium is detected. The temperature calculation is performed by use of the Lebon-Lambermont restricted variational principle, with piecewise polynoms as trial functions. The method has been checked by comparison with some exact results and yields good agreement for transient as well as for quasi-static situations. This method therefore provides a valuable tool for the simulation of the transient behaviour of nuclear reactor fuel rods. (orig.)

  13. Measuring Responsibility and Cooperation in Learning Teams in the University Setting: Validation of a Questionnaire

    Science.gov (United States)

    León-del-Barco, Benito; Mendo-Lázaro, Santiago; Felipe-Castaño, Elena; Fajardo-Bullón, Fernando; Iglesias-Gallego, Damián

    2018-01-01

    Cooperative learning are being used increasingly in the university classroom, in order to promote teamwork among students, improve performance and develop interpersonal competences. Responsibility and cooperation are two fundamental pillars of cooperative learning. Team members’ responsibility is a necessary condition for the team’s success in the assigned tasks. Students must be aware that they depend on each other and should make their maximum effort. On the other hand, in efficient groups, the members cooperate and pool their efforts to achieve the proposed goals. In this research, we propose to create a Questionnaire of Group Responsibility and Cooperation in Learning Teams (CRCG). Participants in this work were 375 students from the Faculty of Teacher Training of the University of Extremadura (Spain). The CRCG has very acceptable psychometric characteristics, good internal consistency, and temporal reliability. Moreover, structural equation analysis allowed us to verify that the latent variables in the two factors found are well defined and, therefore, their assessment is adequate. Besides, we found high significant correlations between the Learning Team Potency Questionnaire (CPEA) and the total score and the factors of the CRCG. This tool will evaluate cooperative skills and offer faculty information in order to prepare students for teamwork and conflict resolution. PMID:29593622

  14. Measuring Responsibility and Cooperation in Learning Teams in the University Setting: Validation of a Questionnaire

    Directory of Open Access Journals (Sweden)

    Benito León-del-Barco

    2018-03-01

    Full Text Available Cooperative learning are being used increasingly in the university classroom, in order to promote teamwork among students, improve performance and develop interpersonal competences. Responsibility and cooperation are two fundamental pillars of cooperative learning. Team members’ responsibility is a necessary condition for the team’s success in the assigned tasks. Students must be aware that they depend on each other and should make their maximum effort. On the other hand, in efficient groups, the members cooperate and pool their efforts to achieve the proposed goals. In this research, we propose to create a Questionnaire of Group Responsibility and Cooperation in Learning Teams (CRCG. Participants in this work were 375 students from the Faculty of Teacher Training of the University of Extremadura (Spain. The CRCG has very acceptable psychometric characteristics, good internal consistency, and temporal reliability. Moreover, structural equation analysis allowed us to verify that the latent variables in the two factors found are well defined and, therefore, their assessment is adequate. Besides, we found high significant correlations between the Learning Team Potency Questionnaire (CPEA and the total score and the factors of the CRCG. This tool will evaluate cooperative skills and offer faculty information in order to prepare students for teamwork and conflict resolution.

  15. Measuring Responsibility and Cooperation in Learning Teams in the University Setting: Validation of a Questionnaire.

    Science.gov (United States)

    León-Del-Barco, Benito; Mendo-Lázaro, Santiago; Felipe-Castaño, Elena; Fajardo-Bullón, Fernando; Iglesias-Gallego, Damián

    2018-01-01

    Cooperative learning are being used increasingly in the university classroom, in order to promote teamwork among students, improve performance and develop interpersonal competences. Responsibility and cooperation are two fundamental pillars of cooperative learning. Team members' responsibility is a necessary condition for the team's success in the assigned tasks. Students must be aware that they depend on each other and should make their maximum effort. On the other hand, in efficient groups, the members cooperate and pool their efforts to achieve the proposed goals. In this research, we propose to create a Questionnaire of Group Responsibility and Cooperation in Learning Teams (CRCG) . Participants in this work were 375 students from the Faculty of Teacher Training of the University of Extremadura (Spain). The CRCG has very acceptable psychometric characteristics, good internal consistency, and temporal reliability. Moreover, structural equation analysis allowed us to verify that the latent variables in the two factors found are well defined and, therefore, their assessment is adequate. Besides, we found high significant correlations between the Learning Team Potency Questionnaire (CPEA) and the total score and the factors of the CRCG. This tool will evaluate cooperative skills and offer faculty information in order to prepare students for teamwork and conflict resolution.

  16. Transient immune impairment after a simulated long-haul flight.

    Science.gov (United States)

    Wilder-Smith, Annelies; Mustafa, Fatima B; Peng, Chung Mien; Earnest, Arul; Koh, David; Lin, Gen; Hossain, Iqbal; MacAry, Paul A

    2012-04-01

    Almost 2 billion people travel aboard commercial airlines every year, with about 20% developing symptoms of the common cold within 1 wk after air travel. We hypothesize that hypobaric hypoxic conditions associated with air travel may contribute to immune impairment. We studied the effects of hypobaric hypoxic conditions during a simulated flight at 8000 ft (2438 m) cruising altitude on immune and stress markers in 52 healthy volunteers (mean age 31) before and on days 1, 4, and 7 after the flight. We did a cohort study using a generalized estimating equation to examine the differences in the repeated measures. Our findings show that the hypobaric hypoxic conditions of a 10-h overnight simulation flight are not associated with severe immune impairment or abnormal IgA or cortisol levels, but with transient impairment in some parameters: we observed a transient decrease in lymphocyte proliferative responses combined with an upregulation in CD69 and CD14 cells and a decrease in HLA-DR in the immediate days following the simulated flight that normalized by day 7 in most instances. These transient immune changes may contribute to an increased susceptibility to respiratory infections commonly seen after long-haul flights.

  17. Teaching Parents about Responsive Feeding through a Vicarious Learning Video: A Pilot Randomized Controlled Trial

    Science.gov (United States)

    Ledoux, Tracey; Robinson, Jessica; Baranowski, Tom; O'Connor, Daniel P.

    2018-01-01

    The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using community-based participatory research methods.…

  18. 3-D transient eddy current calculations for the FELIX cylinder experiments

    International Nuclear Information System (INIS)

    Davey, K.R.; Turner, L.R.

    1986-12-01

    The three-dimensional eddy current transient field problem is formulated first using the U-V method. This method breaks the vector Helmholtz equation into two scalar Helmholtz equations. Null field integral equations and the appropriate boundary conditions are used to set up an identification matrix which is independent of null field point locations. Embedded in the identification matrix are the unknown eigenvalues of the problem representing its impulse response in time. These eigenvalues are found by equating the determinant of the identification matrix to zero. When this initial forcing function is Fourier decomposed into its spatial harmonics, each Fourier component can be associated with a unique eigenvalue by this technique. The true transient solution comes through a convolution of the impulse response so obtained with the particular external field decay governing the problem at hand. The technique is applied to the FELIX cylinder experiments; computed results are compared to data. A pseudoanalytic confirmation of the eigenvalues so obtained is formulated to validate the procedure

  19. Thermal response of a pin-type fusion reactor blanket during steady and transient reactor operation

    International Nuclear Information System (INIS)

    Grotz, S.; Ghoniem, N.M.

    1986-02-01

    The thermal analysis of the blanket examines both the steady-state and transient reactor operations. The steady-state analysis covers full power and fractional power operation whereas the transient analysis examines the effects of power ramps and blanket preheat. The blanket configuration chosen for this study is a helium cooled solid breeder design. We first discuss the full power, steady-state temperature fields in the first wall, beryllium rods, and breeder rods. Next we examine the effects of fractional power on coolant flow and temperature field distributions. This includes power plateaus of 10%, 20%, 50%, 80%, and 100% of full power. Also examined are the restrictions on the rates of power ramping between plateaus. Finally we discuss the power and time requirements for pre-heating the primary from cold iron conditions up to startup temperature (250 0 C)

  20. Simulation of the transient eddy current measurement for the characterization of depth and conductivity of a plate

    International Nuclear Information System (INIS)

    Cheng, Weiying; Komura, Ichiro

    2008-01-01

    A transient eddy current measurement method is presented to determine the thickness and conductivity of a conductive plate. The conductive plate is induced by an air-cored coil, the magnetic flux density along the axial is measured and the various signals corresponding to plates with different thickness and conductivity are calculated using a 3D transient eddy current simulator. Characteristic features are obtained from the transient response. A similarity-based modeling method is utilized in this study to estimate the thickness and conductivity of the conductive plate. (author)

  1. Unifying practice schedules in the timescales of motor learning and performance.

    Science.gov (United States)

    Verhoeven, F Martijn; Newell, Karl M

    2018-06-01

    In this article, we elaborate from a multiple time scales model of motor learning to examine the independent and integrated effects of massed and distributed practice schedules within- and between-sessions on the persistent (learning) and transient (warm-up, fatigue) processes of performance change. The timescales framework reveals the influence of practice distribution on four learning-related processes: the persistent processes of learning and forgetting, and the transient processes of warm-up decrement and fatigue. The superposition of the different processes of practice leads to a unified set of effects for massed and distributed practice within- and between-sessions in learning motor tasks. This analysis of the interaction between the duration of the interval of practice trials or sessions and parameters of the introduced time scale model captures the unified influence of the between trial and session scheduling of practice on learning and performance. It provides a starting point for new theoretically based hypotheses, and the scheduling of practice that minimizes the negative effects of warm-up decrement, fatigue and forgetting while exploiting the positive effects of learning and retention. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Learning "Social Responsibility" in the Workplace: Conjuring, Unsettling, and Folding Boundaries

    Science.gov (United States)

    Fenwick, Tara

    2011-01-01

    This article proceeds from the argument that while the discourse of social responsibility (SR) is increasingly evident in pedagogies circulating through the workplace, its actual practices tend to be obscured beneath complex tensions and moral precepts presented as self-evident. Through an examination of individuals' learning of SR in the…

  3. Research of the transient management in TQNPC

    International Nuclear Information System (INIS)

    Guo Longzhang; Lin Chuanqing

    2008-01-01

    Transient management is the basic technical subject in nuclear power plant. Since the Third Qinshan nuclear power company (TQNPC) successful completes the commissioning in 2003, the transient management work start at the transient management item selection and the flow definition. Now TQNPC have a complete transient management system and the management flow. In the last two years, TNQPC have finished the historic transient data collection for two units, and confirmed that the plant's key systems and equipments are at safe state. The development of the transient management subject would build a reliable foundation for the plant safe operation, plant lifetime management and periodic safety review. (author)

  4. Compressive Transient Imaging

    KAUST Repository

    Sun, Qilin

    2017-04-01

    High resolution transient/3D imaging technology is of high interest in both scientific research and commercial application. Nowadays, all of the transient imaging methods suffer from low resolution or time consuming mechanical scanning. We proposed a new method based on TCSPC and Compressive Sensing to achieve a high resolution transient imaging with a several seconds capturing process. Picosecond laser sends a serious of equal interval pulse while synchronized SPAD camera\\'s detecting gate window has a precise phase delay at each cycle. After capturing enough points, we are able to make up a whole signal. By inserting a DMD device into the system, we are able to modulate all the frames of data using binary random patterns to reconstruct a super resolution transient/3D image later. Because the low fill factor of SPAD sensor will make a compressive sensing scenario ill-conditioned, We designed and fabricated a diffractive microlens array. We proposed a new CS reconstruction algorithm which is able to denoise at the same time for the measurements suffering from Poisson noise. Instead of a single SPAD senor, we chose a SPAD array because it can drastically reduce the requirement for the number of measurements and its reconstruction time. Further more, it not easy to reconstruct a high resolution image with only one single sensor while for an array, it just needs to reconstruct small patches and a few measurements. In this thesis, we evaluated the reconstruction methods using both clean measurements and the version corrupted by Poisson noise. The results show how the integration over the layers influence the image quality and our algorithm works well while the measurements suffer from non-trival Poisson noise. It\\'s a breakthrough in the areas of both transient imaging and compressive sensing.

  5. Characterization of Transient Receptor Potential Vanilloid-1 (TRPV1) Variant Activation by Coal Fly Ash Particles and Associations with Altered Transient Receptor Potential Ankyrin-1 (TRPA1) Expression and Asthma.

    Science.gov (United States)

    Deering-Rice, Cassandra E; Stockmann, Chris; Romero, Erin G; Lu, Zhenyu; Shapiro, Darien; Stone, Bryan L; Fassl, Bernhard; Nkoy, Flory; Uchida, Derek A; Ward, Robert M; Veranth, John M; Reilly, Christopher A

    2016-11-25

    Transient receptor potential (TRP) channels are activated by environmental particulate materials. We hypothesized that polymorphic variants of transient receptor potential vanilloid-1 (TRPV1) would be uniquely responsive to insoluble coal fly ash compared with the prototypical soluble agonist capsaicin. Furthermore, these changes would manifest as differences in lung cell responses to these agonists and perhaps correlate with changes in asthma symptom control. The TRPV1-I315M and -T469I variants were more responsive to capsaicin and coal fly ash. The I585V variant was less responsive to coal fly ash particles due to reduced translation of protein and an apparent role for Ile-585 in activation by particles. In HEK-293 cells, I585V had an inhibitory effect on wild-type TRPV1 expression, activation, and internalization/agonist-induced desensitization. In normal human bronchial epithelial cells, IL-8 secretion in response to coal fly ash treatment was reduced for cells heterozygous for TRPV1-I585V. Finally, both the I315M and I585V variants were associated with worse asthma symptom control with the effects of I315M manifesting in mild asthma and those of the I585V variant manifesting in severe, steroid-insensitive individuals. This effect may be due in part to increased transient receptor potential ankyrin-1 (TRPA1) expression by lung epithelial cells expressing the TRPV1-I585V variant. These findings suggest that specific molecular interactions control TRPV1 activation by particles, differential activation, and desensitization of TRPV1 by particles and/or other agonists, and cellular changes in the expression of TRPA1 as a result of I585V expression could contribute to variations in asthma symptom control. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Analytical model for transient fluid mixing in upper outlet plenum of an LMFBR

    International Nuclear Information System (INIS)

    Yang, J.W.; Agrawal, A.K.

    1976-01-01

    A two-zone mixing model based on the lumped-parameter approach was developed for the analysis of transient thermal response in the outlet plenum of an LMFBR. The maximum penetration of core flow is used as the criterion for dividing the sodium region into two mixing zones. The model considers the transient sodium temperature affected by the thermal expansion of sodium, heat transfer with cover gas, heat capacity of different sections of metal and the addition of by-pass flow into the plenum. The results of numerical calculations indicate that effects of flow stratification, chimney height, metal heat capacity and by-pass flow are important for transient sodium temperature calculation. Thermal expansion of sodium and heat transfer with the cover gas do not play any significant role on sodium temperature

  7. Extending Basic Learning Opportunities: Challenge and Response. UNESCO-UNICEF Co-operative Programme Digest No. 16.

    Science.gov (United States)

    Prakasha, Veda; And Others

    This digest focuses on problems encountered in the expansion of facilities for universal primary education and responses being developed to overcome these problems. The central message of the document is that nonformal structures of learning and community involvement play a key role in the expansion of basic learning opportunities in the…

  8. Calculation of ex-core detector responses

    Energy Technology Data Exchange (ETDEWEB)

    Wouters, R. de; Haedens, M. [Tractebel Engineering, Brussels (Belgium); Baenst, H. de [Electrabel, Brussels (Belgium)

    2005-07-01

    The purpose of this work carried out by Tractebel Engineering, is to develop and validate a method for predicting the ex-core detector responses in the NPPs operated by Electrabel. Practical applications are: prediction of ex-core calibration coefficients for startup power ascension, replacement of xenon transients by theoretical predictions, and analysis of a Rod Drop Accident. The neutron diffusion program PANTHER calculates node-integrated fission sources which are combined with nodal importance representing the contribution of a neutron born in that node to the ex-core response. These importance are computed with the Monte Carlo program MCBEND in adjoint mode, with a model of the whole core at full power. Other core conditions are treated using sensitivities of the ex-core responses to water densities, computed with forward Monte Carlo. The Scaling Factors (SF), or ratios of the measured currents to the calculated response, have been established on a total of 550 in-core flux maps taken in four NPPs. The method has been applied to 15 startup transients, using the average SF obtained from previous cycles, and to 28 xenon transients, using the SF obtained from the in-core map immediately preceding the transient. The values of power (P) and axial offset (AOi) reconstructed with the theoretical calibration agree well with the measured values. The ex-core responses calculated during a rod drop transient have been successfully compared with available measurements, and with theoretical data obtained by alternative methods. In conclusion, the method is adequate for the practical applications previously listed. (authors)

  9. A transient absorption study of allophycocyanin

    Indian Academy of Sciences (India)

    Transient dynamics of allophycocyanin trimers and monomers are observed by using the pump-probe, transient absorption technique. The origin of spectral components of the transient absorption spectra is discussed in terms of both kinetics and spectroscopy. We find that the energy gap between the ground and excited ...

  10. The joy of transient chaos

    Energy Technology Data Exchange (ETDEWEB)

    Tél, Tamás [Institute for Theoretical Physics, Eötvös University, and MTA-ELTE Theoretical Physics Research Group, Pázmány P. s. 1/A, Budapest H-1117 (Hungary)

    2015-09-15

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  11. The joy of transient chaos.

    Science.gov (United States)

    Tél, Tamás

    2015-09-01

    We intend to show that transient chaos is a very appealing, but still not widely appreciated, subfield of nonlinear dynamics. Besides flashing its basic properties and giving a brief overview of the many applications, a few recent transient-chaos-related subjects are introduced in some detail. These include the dynamics of decision making, dispersion, and sedimentation of volcanic ash, doubly transient chaos of undriven autonomous mechanical systems, and a dynamical systems approach to energy absorption or explosion.

  12. The ZTF Bright Transient Survey

    Science.gov (United States)

    Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Miller, A. A.; Taggart, K.; Perley, D. A.; Gooba, A.

    2018-06-01

    As a supplement to the Zwicky Transient Facility (ZTF; ATel #11266) public alerts (ATel #11685) we plan to report (following ATel #11615) bright probable supernovae identified in the raw alert stream from the ZTF Northern Sky Survey ("Celestial Cinematography"; see Bellm & Kulkarni, 2017, Nature Astronomy 1, 71) to the Transient Name Server (https://wis-tns.weizmann.ac.il) on a daily basis; the ZTF Bright Transient Survey (BTS; see Kulkarni et al., 2018; arXiv:1710.04223).

  13. Transient thermal-mechanical behavior of cracked glass-cloth-reinforced epoxy laminates at low temperatures

    International Nuclear Information System (INIS)

    Shindo, Y.; Ueda, S.

    1997-01-01

    We consider the transient thermal-mechanical response of cracked G-10CR glass-cloth-reinforced epoxy laminates with temperature-dependent properties. The glass-cloth-reinforced epoxy laminates are suddenly cooled on the surfaces. A generalized plane strain finite element model is used to study the influence of warp angle and crack formation on the thermal shock behavior of two-layer woven laminates at low temperatures. Numerical calculations are carried out, and the transient temperature distribution and the thermal-mechanical stresses are shown graphically

  14. Learning-dependent and -independent enhancement of mitral/tufted cell glomerular odor responses following olfactory fear conditioning in awake mice.

    Science.gov (United States)

    Ross, Jordan M; Fletcher, Max L

    2018-04-18

    Associative fear learning produces fear toward the conditioned stimulus (CS) and often generalization, the expansion of fear from the CS to similar, unlearned stimuli. However, how fear learning affects early sensory processing of learned and unlearned stimuli in relation to behavioral fear responses to these stimuli remains unclear. We subjected male and female mice expressing the fluorescent calcium indicator GCaMP3 in olfactory bulb mitral and tufted cells to a classical olfactory fear conditioning paradigm. We then used awake, in vivo calcium imaging to quantify learning-induced changes in glomerular odor responses, which constitute the first site of olfactory processing in the brain. The results demonstrate that odor-shock pairing non-specifically enhances glomerular odor representations in a learning-dependent manner and increases representational similarity between the CS and non-conditioned odors, potentially priming the system towards generalization of learned fear. Additionally, CS-specific glomerular enhancements remain even when associative learning is blocked, suggesting two separate mechanisms lead to enhanced glomerular responses following odor-shock pairings. SIGNIFICANCE STATEMENT In the olfactory bulb (OB), odors are uniquely coded in a spatial map that represents odor identity, making the OB a unique model system for investigating how learned fear alters sensory processing. Classical fear conditioning causes fear of the conditioned stimulus (CS) and of neutral stimuli, known as generalization. Combining fear conditioning with fluorescent calcium imaging of OB glomeruli, we found enhanced glomerular responses of the CS as well as neutral stimuli in awake mice, which mirrors fear generalization. We report that CS and neutral stimuli enhancements are, respectively, learning- independent and learning-dependent. Together, these results reveal distinct mechanisms leading to enhanced OB processing of fear-inducing stimuli and provide important

  15. Learned helplessness in the rat: effect of response topography in a within-subject design.

    Science.gov (United States)

    dos Santos, Cristiano Valerio; Gehm, Tauane; Hunziker, Maria Helena Leite

    2011-02-01

    Three experiments investigated learned helplessness in rats manipulating response topography within-subject and different intervals between treatment and tests among groups. In Experiment 1, rats previously exposed to inescapable shocks were tested under an escape contingency where either jumping or nose poking was required to terminate shocks; tests were run either 1, 14 or 28 days after treatment. Most rats failed to jump, as expected, but learned to nose poke, regardless of the interval between treatment and tests and order of testing. The same results were observed in male and female rats from a different laboratory (Experiment 2) and despite increased exposure to the escape contingencies using a within-subject design (Experiment 3). Furthermore, no evidence of helplessness reversal was observed, since animals failed to jump even after having learned to nose-poke in a previous test session. These results are not consistent with a learned helplessness hypothesis, which claims that shock (un)controllability is the key variable responsible for the effect. They are nonetheless consistent with the view that inescapable shocks enhance control by irrelevant features of the relationship between the environment and behavior. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Quick Response (QR) Codes for Audio Support in Foreign Language Learning

    Science.gov (United States)

    Vigil, Kathleen Murray

    2017-01-01

    This study explored the potential benefits and barriers of using quick response (QR) codes as a means by which to provide audio materials to middle-school students learning Spanish as a foreign language. Eleven teachers of Spanish to middle-school students created transmedia materials containing QR codes linking to audio resources. Students…

  17. Explosive and radio-selected Transients: Transient Astronomy with ...

    Indian Academy of Sciences (India)

    40

    sitive measurements will lead to very accurate mass loss estimation in these supernovae. .... transients are powerful probes of intervening media owing to dispersion ...... A., & Chandra, P. 2011, Nature Communications,. 2, 175. Chakraborti, S.

  18. Early life status epilepticus and stress have distinct and sex-specific effects on learning, subsequent seizure outcomes, including anticonvulsant response to phenobarbital.

    Science.gov (United States)

    Akman, Ozlem; Moshé, Solomon L; Galanopoulou, Aristea S

    2015-02-01

    Neonatal status epilepticus (SE) is often associated with adverse cognitive and epilepsy outcomes. We investigate the effects of three episodes of kainic acid-induced SE (3KA-SE) and maternal separation in immature rats on subsequent learning, seizure susceptibility, and consequences, and the anticonvulsant effects of phenobarbital, according to sex, type, and age at early life (EL) event. 3KA-SE or maternal separation was induced on postnatal days (PN) 4-6 or 14-16. Rats were tested on Barnes maze (PN16-19), or lithium-pilocarpine SE (PN19) or flurothyl seizures (PN32). The anticonvulsant effects of phenobarbital (20 or 40 mg/kg/rat, intraperitoneally) pretreatment were tested on flurothyl seizures. FluoroJadeB staining assessed hippocampal injury. 3KA-SE or separation on PN4-6 caused more transient learning delays in males and did not alter lithium-pilocarpine SE latencies, but aggravated its outcomes in females. Anticonvulsant effects of phenobarbital were preserved and potentiated in specific groups depending on sex, type, and age at EL event. Early life 3KA-SE and maternal separation cause more but transient cognitive deficits in males but aggravate the consequences of subsequent lithium-pilocarpine SE in females. In contrast, on flurothyl seizures, EL events showed either beneficial or no effect, depending on gender, type, and age at EL events. © 2014 John Wiley & Sons Ltd.

  19. Service Learning and Its Influenced to Pre-Service Teachers: Social Responsibility and Self-Efficacy Study

    Science.gov (United States)

    Prasertsang, Parichart; Nuangchalerm, Prasart; Pumipuntu, Chaloey

    2013-01-01

    The purpose of the research was to study pre-service teachers on social responsibility and self-efficacy through service learning. The mixed methodology included two major procedures (i) the actual use of a developed service learning instructional model by means of action research principles and qualitative research and (ii) the study into the…

  20. Transient analysis and leakage detection algorithm using GA and HS algorithm for a pipeline system

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Hyun; Yoo, Wan Suk; Oh, Kwang Jung; Hwang, In Sung; Oh, Jeong Eun [Pusan National University, Pusan (Korea, Republic of)

    2006-03-15

    The impact of leakage was incorporated into the transfer functions of the complex head and discharge. The impedance transfer functions for the various leaking pipeline systems were also derived. Hydraulic transients could be efficiently analyzed by the developed method. The simulation of normalized pressure variation using the method of characteristics and the impulse response method shows good agreement to the condition of turbulent flow. The leak calibration could be performed by incorporation of the impulse response method with Genetic Algorithm (GA) and Harmony Search (HS). The objective functions for the leakage detection can be made using the pressure-head response at the valve, or the pressure-head or the flow response at a certain point of the pipeline located upstream from the valve. The proposed method is not constrained by the Courant number to control the numerical dissipation of the method of characteristics. The limitations associated with the discreteness of the pipeline system in the inverse transient analysis can be neglected in the proposed method.

  1. Transient analysis and leakage detection algorithm using GA and HS algorithm for a pipeline system

    International Nuclear Information System (INIS)

    Kim, Sang Hyun; Yoo, Wan Suk; Oh, Kwang Jung; Hwang, In Sung; Oh, Jeong Eun

    2006-01-01

    The impact of leakage was incorporated into the transfer functions of the complex head and discharge. The impedance transfer functions for the various leaking pipeline systems were also derived. Hydraulic transients could be efficiently analyzed by the developed method. The simulation of normalized pressure variation using the method of characteristics and the impulse response method shows good agreement to the condition of turbulent flow. The leak calibration could be performed by incorporation of the impulse response method with Genetic Algorithm (GA) and Harmony Search (HS). The objective functions for the leakage detection can be made using the pressure-head response at the valve, or the pressure-head or the flow response at a certain point of the pipeline located upstream from the valve. The proposed method is not constrained by the Courant number to control the numerical dissipation of the method of characteristics. The limitations associated with the discreteness of the pipeline system in the inverse transient analysis can be neglected in the proposed method

  2. The Impact of Student Response Systems on the Learning Experience of Undergraduate Psychology Students

    Science.gov (United States)

    Walklet, Elaine; Davis, Sarah; Farrelly, Daniel; Muse, Kate

    2016-01-01

    Student response systems (SRS) are hand-held devices or mobile phone polling systems which collate real-time, individual responses to on-screen questions. Previous research examining their role in higher education has highlighted both advantages and disadvantages of their use. This paper explores how different SRS influence the learning experience…

  3. Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

    Science.gov (United States)

    Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

    2016-03-01

    Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

  4. The effect of early administration of glucocorticoids on learning and ...

    African Journals Online (AJOL)

    It has been observed that steroids administered postnatally may have transient retarding effect on learning and memory functions, and that animal age and sex may modify such effects. This study aims to illustrate the effect of early administration of glucocorticoids on learning and spatial memory. Wistar rat pups were ...

  5. Peer-Allocated Instant Response (PAIR): Computional allocation of peer tutors in learning communities

    NARCIS (Netherlands)

    Westera, Wim

    2009-01-01

    Westera, W. (2007). Peer-Allocated Instant Response (PAIR): Computational allocation of peer tutors in learning communities. Journal of Artificial Societies and Social Simulation, http://jasss.soc.surrey.ac.uk/10/2/5.html

  6. Electromagnetic transients in power cables

    CERN Document Server

    da Silva, Filipe Faria

    2013-01-01

    From the more basic concepts to the most advanced ones where long and laborious simulation models are required, Electromagnetic Transients in Power Cables provides a thorough insight into the study of electromagnetic transients and underground power cables. Explanations and demonstrations of different electromagnetic transient phenomena are provided, from simple lumped-parameter circuits to complex cable-based high voltage networks, as well as instructions on how to model the cables.Supported throughout by illustrations, circuit diagrams and simulation results, each chapter contains exercises,

  7. On the best learning algorithm for web services response time prediction

    DEFF Research Database (Denmark)

    Madsen, Henrik; Albu, Razvan-Daniel; Popentiu-Vladicescu, Florin

    2013-01-01

    In this article we will examine the effect of different learning algorithms, while training the MLP (Multilayer Perceptron) with the intention of predicting web services response time. Web services do not necessitate a user interface. This may seem contradictory to most people's concept of what...... an application is. A Web service is better imagined as an application "segment," or better as a program enabler. Performance is an important quality aspect of Web services because of their distributed nature. Predicting the response of web services during their operation is very important....

  8. ORTAP: a nuclear steam supply system simulation for the dynamic analysis of high temperature gas cooled reactor transients

    International Nuclear Information System (INIS)

    Cleveland, J.C.; Hedrick, R.A.; Ball, S.J.; Delene, J.G.

    1977-01-01

    ORTAP was developed to predict the dynamic behavior of the high temperature gas cooled reactor (HTGR) Nuclear Steam Supply System for normal operational transients and postulated accident conditions. It was developed for the Nuclear Regulatory Commission (NRC) as an independent means of obtaining conservative predictions of the transient response of HTGRs over a wide range of conditions. The approach has been to build sufficient detail into the component models so that the coupling between the primary and secondary systems can be accurately represented and so that transients which cover a wide range of conditions can be simulated. System components which are modeled in ORTAP include the reactor core, a typical reheater and steam generator module, a typical helium circulator and circulator turbine and the turbine generator plant. The major plant control systems are also modeled. Normal operational transients which can be analyzed with ORTAP include reactor start-up and shutdown, normal and rapid load changes. Upset transients which can be analyzed with ORTAP include reactor trip, turbine trip and sudden reduction in feedwater flow. ORTAP has also been used to predict plant response to emergency or faulted conditions such as primary system depressurization, loss of primary coolant flow and uncontrolled removal of control poison from the reactor core

  9. Spectroscopic classification of transients

    DEFF Research Database (Denmark)

    Stritzinger, M. D.; Fraser, M.; Hummelmose, N. N.

    2017-01-01

    We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017.......We report the spectroscopic classification of several transients based on observations taken with the Nordic Optical Telescope (NOT) equipped with ALFOSC, over the nights 23-25 August 2017....

  10. Transient or permanent fisheye views

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper

    2012-01-01

    Transient use of information visualization may support specific tasks without permanently changing the user interface. Transient visualizations provide immediate and transient use of information visualization close to and in the context of the user’s focus of attention. Little is known, however......, about the benefits and limitations of transient visualizations. We describe an experiment that compares the usability of a fisheye view that participants could call up temporarily, a permanent fisheye view, and a linear view: all interfaces gave access to source code in the editor of a widespread...... programming environment. Fourteen participants performed varied tasks involving navigation and understanding of source code. Participants used the three interfaces for between four and six hours in all. Time and accuracy measures were inconclusive, but subjective data showed a preference for the permanent...

  11. Low latitude ionospheric TEC responses to dynamical complexity quantifiers during transient events over Nigeria

    Science.gov (United States)

    Ogunsua, Babalola

    2018-04-01

    In this study, the values of chaoticity and dynamical complexity parameters for some selected storm periods in the year 2011 and 2012 have been computed. This was done using detrended TEC data sets measured from Birnin-Kebbi, Torro and Enugu global positioning system (GPS) receiver stations in Nigeria. It was observed that the significance of difference (SD) values were mostly greater than 1.96 but surprisingly lower than 1.96 in September 29, 2011. The values of the computed SD were also found to be reduced in most cases just after the geomagnetic storm with immediate recovery a day after the main phase of the storm while the values of Lyapunov exponent and Tsallis entropy remains reduced due to the influence of geomagnetic storms. It was also observed that the value of Lyapunov exponent and Tsallis entropy reveals similar variation pattern during storm period in most cases. Also recorded surprisingly were lower values of these dynamical quantifiers during the solar flare event of August 8th and 9th of the year 2011. The possible mechanisms responsible for these observations were further discussed in this work. However, our observations show that the ionospheric effects of some other possible transient events other than geomagnetic storms can also be revealed by the variation of chaoticity and dynamical complexity.

  12. Occurrence and predictors of persistent impaired glucose tolerance after acute ischemic stroke or transient ischemic attack

    OpenAIRE

    Fonville, Susanne; Hertog, Heleen; Zandbergen, Adrienne; Koudstaal, Peter Jan; Lingsma, Hester

    2014-01-01

    textabstractBackground Impaired glucose tolerance is often present in patients with a transient ischemic attack (TIA) or ischemic stroke and doubles the risk of recurrent stroke. This impaired glucose tolerance can be transient, reflecting an acute stress response, or persistent, representing undiagnosed impaired glucose metabolism possibly requiring treatment. We aimed to assess the occurrence of persistent impaired glucose tolerance after a stroke or TIA and to develop a prediction model to...

  13. Informal Learning in Online Knowledge Communities: Predicting Community Response to Visitor Inquiries

    NARCIS (Netherlands)

    Nistor, Nicolae; Dascalu, Mihai; Stavarache, Lucia Larise; Serafin, Yvonne; Trausan-Matu, Stefan

    2016-01-01

    Nistor, N., Dascalu, M., Stavarache, L.L., Serafin, Y., & Trausan-Matu, S. (2015). Informal Learning in Online Knowledge Communities: Predicting Community Response to Visitor Inquiries. In G. Conole, T. Klobucar, C. Rensing, J. Konert & É. Lavoué (Eds.), 10th European Conf. on Technology Enhanced

  14. Motor Skill Learning and Corticospinal Excitability

    DEFF Research Database (Denmark)

    Christiansen, Lasse

    Background Motor skill learning (MSL) is the persistent increase in performance of a skill obtained through practice. This process is associated with changes throughout the central nervous system. One of these is a change in corticospinal excitability (CSE) assessable with Transcranial Magnetic...... a novel visuomotor skill. I hypothesized that changes in CSE accompanying long-term motor practice relate to the process of learning rather than repetitive practice on an acquired skill and investigated this by incrementally increasing task difficulty and thus postponing saturation of learning....... Furthermore, we aimed to investigate the feasibility of applying paired associative stimulation to the investigation of learning-dependent motor cortical plasticity by comparing the transient increase in CSE accompanying motor skill learning to the associative plasticity induced by pairing electrical motor...

  15. An analytical and experimental investigation of natural circulation transients in a model pressurized water reactor

    International Nuclear Information System (INIS)

    Massoud, M.

    1987-01-01

    Natural Circulation phenomena in a simulated PWR was investigated experimentally and analytically. The experimental investigation included determination of system characteristics as well as system response to the imposed transient under symmetric and asymmetric operations. System characteristics were used to obtain correlation for heat transfer coefficient in heat exchangers, system flow resistance, and system buoyancy heat. Asymmetric transients were imposed to study flow oscillation and possible instability. The analytical investigation encompassed development of mathematical model for single-phase, steady-state and transient natural circulation as well as modification of existing model for two-phase flow analysis of phenomena such as small break LOCA, high pressure coolant injection and pump coast down. The developed mathematical model for single-phase analysis was computer coded to simulate the imposed transients. The computer program, entitled ''Symmetric and Asymmetric Analysis of Single-Phase Flow (SAS),'' were employed to simulate the imposed transients. It closely emulated the system behavior throughout the transient and subsequent steady-state. Modifications for two-phase flow analysis included addition of models for once-through steam generator and electric heater rods. Both programs are faster than real time. Off-line, they can be used for prediction and training applications while on-line they serve for simulation and signal validation. The programs can also be used to determine the sensitivity of natural circulation behavior to variation of inputs such as secondary distribution and power transients

  16. Quantification of metabolically active transient storage (MATS) in two reaches with contrasting transient storage and ecosystem respiration

    Science.gov (United States)

    Alba Argerich; Roy Haggerty; Eugènia Martí; Francesc Sabater; Jay. Zarnetske

    2011-01-01

    Water transient storage zones are hotspots for metabolic activity in streams although the contribution of different types of transient storage zones to the whole�]reach metabolic activity is difficult to quantify. In this study we present a method to measure the fraction of the transient storage that is metabolically active (MATS) in two consecutive reaches...

  17. From Idea to Action: Promoting Responsible Management Education through a Semester-Long Academic Integrity Learning Project

    Science.gov (United States)

    Lavine, Marc H.; Roussin, Christopher J.

    2012-01-01

    The authors describe a semester-long action-learning project where undergraduate or graduate management students learn about ethics, responsibility, and organizational behavior by examining the policy of their college or university that addresses academic integrity. Working in teams, students adopt a stakeholder management approach as they make…

  18. Pressure transients across HEPA filters

    International Nuclear Information System (INIS)

    Gregory, W.; Reynolds, G.; Ricketts, C.; Smith, P.R.

    1977-01-01

    Nuclear fuel cycle facilities require ventilation for health and safety reasons. High efficiency particulate air (HEPA) filters are located within ventilation systems to trap radioactive dust released in reprocessing and fabrication operations. Pressure transients within the air cleaning systems may be such that the effectiveness of the filtration system is questioned under certain accident conditions. These pressure transients can result from both natural and man-caused phenomena: atmospheric pressure drop caused by a tornado or explosions and nuclear excursions initiate pressure pulses that could create undesirable conditions across HEPA filters. Tornado depressurization is a relatively slow transient as compared to pressure pulses that result from combustible hydrogen-air mixtures. Experimental investigation of these pressure transients across air cleaning equipment has been undertaken by Los Alamos Scientific Laboratory and New Mexico State University. An experimental apparatus has been constructed to impose pressure pulses across HEPA filters. The experimental equipment is described as well as preliminary results using variable pressurization rates. Two modes of filtration of an aerosol injected upstream of the filter is examined. A laser instrumentation for measuring the aerosol release, during the transient, is described

  19. Recent development of transient electronics

    Directory of Open Access Journals (Sweden)

    Huanyu Cheng

    2016-01-01

    Full Text Available Transient electronics are an emerging class of electronics with the unique characteristic to completely dissolve within a programmed period of time. Since no harmful byproducts are released, these electronics can be used in the human body as a diagnostic tool, for instance, or they can be used as environmentally friendly alternatives to existing electronics which disintegrate when exposed to water. Thus, the most crucial aspect of transient electronics is their ability to disintegrate in a practical manner and a review of the literature on this topic is essential for understanding the current capabilities of transient electronics and areas of future research. In the past, only partial dissolution of transient electronics was possible, however, total dissolution has been achieved with a recent discovery that silicon nanomembrane undergoes hydrolysis. The use of single- and multi-layered structures has also been explored as a way to extend the lifetime of the electronics. Analytical models have been developed to study the dissolution of various functional materials as well as the devices constructed from this set of functional materials and these models prove to be useful in the design of the transient electronics.

  20. Transient epileptic amnesia: clinical report of a cohort of patients.

    Science.gov (United States)

    Lapenta, Leonardo; Brunetti, Valerio; Losurdo, Anna; Testani, Elisa; Giannantoni, Nadia Mariagrazia; Quaranta, Davide; Di Lazzaro, Vincenzo; Della Marca, Giacomo

    2014-07-01

    Transient epileptic amnesia is a seizure disorder, usually with onset in the middle-elderly and good response to low dosages of antiepileptic drugs. We describe the clinical, electroencephalography (EEG), and neuroimaging features of 11 patients with a temporal lobe epilepsy characterized by amnesic seizures as the sole or the main symptom. We outline the relevance of a detailed clinical history to recognize amnesic seizures and to avoid the more frequent misdiagnoses. Moreover, the response to monotherapy was usually good, although the epileptic disorder was symptomatic of acquired lesions in the majority of patients.