Boom or bust? A comparative analysis of transient population dynamics in plants
DEFF Research Database (Denmark)
Stott, Iain; Franco, Miguel; Carslake, David
2010-01-01
researchers as further possible effectors of complicated dynamics. Previously published methods of transient analysis have tended to require knowledge of initial population structure. However, this has been overcome by the recent development of the parametric Kreiss bound (which describes how large...... a population must become before reaching its maximum possible transient amplification following a disturbance) and the extension of this and other transient indices to simultaneously describe both amplified and attenuated transient dynamics. We apply the Kreiss bound and other transient indices to a data base...... worrying artefact of basic model parameterization. Synthesis. Transient indices describe how big or how small plant populations can get, en route to long-term stable rates of increase or decline. The patterns we found in the potential for transient dynamics, across many species of plants, suggest...
Sensitivity of Transient Phenomena Analysis of the Francis Turbine Power Plants
Directory of Open Access Journals (Sweden)
Viktor Iliev
2015-08-01
Full Text Available The accurate definition of the transient phenomena of the hydroelectric power plant (HPP and its units, taking into account various aspects of operation is an essential requirement for design, performances and control of HPPs. Numerical analysis of transient phenomena, such as increase of the rotational speed (runaway of the units, increase of the pressure (turbine inlet head in the hydraulic system (water hammer and water level oscillation in the surge tank is presented. The results of transient phenomena analyses are relied upon for very costly engineering decisions. Because of this, it is important that the researcher understands the effect unknown modeling parameters on the result of transient analysis. Usually, different researchers may choose alternate values for an unknown modeling parameter and this can have significant effects on the results. The main aim in this paper is to investigate of the sensitivity of transient phenomena analysis with variation in modeling parameters such as pipeline friction factor, wave speed, turbine guide vanes closing law, surge tank throttling coefficient and generator inertia.
Transient analysis of a molten salt central receiver (MSCR) in a solar power plant
Joshi, A.; Wang, C.; Akinjiola, O.; Lou, X.; Neuschaefer, C.; Quinn, J.
2016-05-01
Alstom is developing solar power tower plants utilizing molten salt as the working fluid. In solar power tower, the molten salt central receiver (MSCR) atop of the tower is constructed of banks of tubes arranged in panels creating a heat transfer surface exposed to the solar irradiation from the heliostat field. The molten salt heat transfer fluid (HTF), in this case 60/40%wt NaNO3-KNO3, flows in serpentine flow through the surface collecting sensible heat thus raising the HTF temperature from 290°C to 565°C. The hot molten salt is stored and dispatched to produce superheated steam in a steam generator, which in turn produces electricity in the steam turbine generator. The MSCR based power plant with a thermal energy storage system (TESS) is a fully dispatchable renewable power plant with a number of opportunities for operational and economic optimization. This paper presents operation and controls challenges to the MSCR and the overall power plant, and the use of dynamic model computer simulation based transient analyses applied to molten salt based solar thermal power plant. This study presents the evaluation of the current MSCR design, using a dynamic model, with emphasis on severe events affecting critical process response, such as MS temperature deviations, and recommend MSCR control design improvements based on the results. Cloud events are the scope of the transient analysis presented in this paper. The paper presents results from a comparative study to examine impacts or effects on key process variables related to controls and operation of the MSCR plant.
Energy Technology Data Exchange (ETDEWEB)
Vinai, P
2007-10-15
For the development, design and licensing of a nuclear power plant (NPP), a sound safety analysis is necessary to study the diverse physical phenomena involved in the system behaviour under operational and transient conditions. Such studies are based on detailed computer simulations. With the progresses achieved in computer technology and the greater availability of experimental and plant data, the use of best estimate codes for safety evaluations has gained increasing acceptance. The application of best estimate safety analysis has raised new problems that need to be addressed: it has become more crucial to assess as to how reliable code predictions are, especially when they need to be compared against safety limits that must not be crossed. It becomes necessary to identify and quantify the various possible sources of uncertainty that affect the reliability of the results. Currently, such uncertainty evaluations are generally based on experts' opinion. In the present research, a novel methodology based on a non-parametric statistical approach has been developed for objective quantification of best-estimate code uncertainties related to the physical models used in the code. The basis is an evaluation of the accuracy of a given physical model achieved by comparing its predictions with experimental data from an appropriate set of separate-effect tests. The differences between measurements and predictions can be considered stochastically distributed, and thus a statistical approach can be employed. The first step was the development of a procedure for investigating the dependence of a given physical model's accuracy on the experimental conditions. Each separate-effect test effectively provides a random sample of discrepancies between measurements and predictions, corresponding to a location in the state space defined by a certain number of independent system variables. As a consequence, the samples of 'errors', achieved from analysis of the entire
RETRAN analysis results of feedwater pump trip transient for Lungmen ABWR Plant
Energy Technology Data Exchange (ETDEWEB)
Ma Shaoshih, E-mail: ssma@iner.gov.tw [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2, Kuang Fu Rd., HsinChu City 30013, Taiwan (China); Institute of Nuclear Energy Research, Atomic Energy Council, ROC, P.O. Box 3-3, Lungtan, Taoyuan 325, Taiwan (China); Shih Chunkuan [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2, Kuang Fu Rd., HsinChu City 30013, Taiwan (China); Yuann Yngruey [Institute of Nuclear Energy Research, Atomic Energy Council, ROC, P.O. Box 3-3, Lungtan, Taoyuan 325, Taiwan (China)
2011-07-15
Highlights: > The RETRAN model was used to predict one feedwater pump trip (FWPT) transient. > The result shows that the margin sustains at least 30 cm above the L3 setpoint. > The unavailable motor driven pump case eventually actuates the low level scram signal. > The lowest load line case without motor driven pump still actuates the L3 scram. - Abstract: The RETRAN model of Lungmen ABWR was used to simulate one feedwater pump trip (FWPT) transient of the Lungmen start-up test program. The purpose of this test is to verify the capability of one surviving Turbine Driven Reactor Feedwater Pump (TDRFP) plus a Motor Driven Feedwater Pump (MDRFP) to continue operating the reactor stably following the incident. There are three major control systems implanted in Lungmen RETRAN model (LRM), which include Recirculation Flow Control System (RFCS), Steam Bypass and Pressure Control System (SBPCS), and Feedwater Control System (FWCS). The reactor water level margin with respect to the low level scram setpoint in the transient is monitored to confirm whether the acceptance criteria has been satisfied, which depends on the responses of the control systems to the FWPT transient. The analysis result of base case at 100% rated power/100% rated core flow with automatic start of MDRFP demonstrates that the acceptance criteria are met, which shows that the water level still sustains ample margin of 30 cm above the low level setpoint, and the reactor does not scram. To get more insight into the function of MDRFP, a set of sensitivity studies with the assumption of unavailable MDRFP, and with a different initial condition which extended to the maximum allowable core flow of 111% rated at rated power, was conducted to verify the superior capability of power coastdown due to the RIPs runback logic under the lowest load line, and also the delay time of the Reactor Internal Pumps (RIPs). Finally, it is concluded that FWPT transient without start of MDRFP eventually actuates the low level
Fault Transient Analysis and Protection Performance Evaluation within a Large-scale PV Power Plant
Directory of Open Access Journals (Sweden)
Wen Jinghua
2016-01-01
Full Text Available In this paper, a short-circuit test within a large-scale PV power plant with a total capacity of 850MWp is discussed. The fault currents supplied by the PV generation units are presented and analysed. According to the fault behaviour, the existing protection coordination principles with the plant are considered and their performances are evaluated. Moreover, these protections are examined in simulation platform under different operating situations. A simple measure with communication system is proposed to deal with the foreseeable problem about the current protection scheme in the PV power plant.
Isolation, culture, and transient transformation of plant protoplasts.
Shen, Jinbo; Fu, Jiaxin; Ma, Jin; Wang, Xiangfeng; Gao, Caiji; Zhuang, ChuXiong; Wan, Jianmin; Jiang, Liwen
2014-06-03
Transient gene expression in protoplasts, which has been used in several plant species, is an important and versatile tool for rapid functional gene analysis, protein subcellular localization, and biochemical manipulations. This unit describes transient gene expression by electroporation of DNA into protoplasts of Arabidopsis or tobacco suspension-cultured cells and by polyethylene glycol (PEG)-mediated DNA transformation into protoplasts derived from rice leaf sheaths. PEG-mediated DNA transformation for transient gene expression in rice protoplasts in suspension culture is also described as an alternative technique. Methods for collecting intracellular and secreted proteins are also provided.
Directory of Open Access Journals (Sweden)
von Arnim Albrecht G
2009-05-01
Full Text Available Abstract Background Plant genome sequencing has resulted in the identification of a large number of uncharacterized genes. To investigate these unknown gene functions, several transient transformation systems have been developed as quick and convenient alternatives to the lengthy transgenic assay. These transient assays include biolistic bombardment, protoplast transfection and Agrobacterium-mediated transient transformation, each having advantages and disadvantages depending on the research purposes. Results We present a novel transient assay based on cocultivation of young Arabidopsis (Arabidopsis thaliana seedlings with Agrobacterium tumefaciens in the presence of a surfactant which does not require any dedicated equipment and can be carried out within one week from sowing seeds to protein analysis. This Fast Agro-mediated Seedling Transformation (FAST was used successfully to express a wide variety of constructs driven by different promoters in Arabidopsis seedling cotyledons (but not roots in diverse genetic backgrounds. Localizations of three previously uncharacterized proteins were identified by cotransformation with fluorescent organelle markers. The FAST procedure requires minimal handling of seedlings and was also adaptable for use in 96-well plates. The high transformation efficiency of the FAST procedure enabled protein detection from eight transformed seedlings by immunoblotting. Protein-protein interaction, in this case HY5 homodimerization, was readily detected in FAST-treated seedlings with Förster resonance energy transfer and bimolecular fluorescence complementation techniques. Initial tests demonstrated that the FAST procedure can also be applied to other dicot and monocot species, including tobacco, tomato, rice and switchgrass. Conclusion The FAST system provides a rapid, efficient and economical assay of gene function in intact plants with minimal manual handling and without dedicated device. This method is potentially
Transient Error Data Analysis.
1979-05-01
Analysis is 3.2 Graphical Data Analysis 16 3.3 General Statistics and Confidence Intervals 1" 3.4 Goodness of Fit Test 15 4. Conclusions 31 Acknowledgements...MTTF per System Technology Mechanism Processor Processor MT IE . CMUA PDP-10, ECL Parity 44 hrs. 800-1600 hrs. 0.03-0.06 Cm* LSI-1 1, NMOS Diagnostics...OF BAD TIME ERRORS: 6 TOTAL NUMBER OF ENTRIES FOR ALL INPUT FILESs 18445 TIME SPAN: 1542 HRS., FROM: 17-Feb-79 5:3:11 TO: 18-1Mj-79 11:30:99
Energy Technology Data Exchange (ETDEWEB)
Shim, Suk Koo; Jang, Won Pyo; Kim, Heui Chul; Kim, Kyung Doo; Lee, Sung Jae; Hah, Kyooi Suk; Song, Soon Jah; Um, Kil Sub; Yoon, Han Yung; Kim, Doo Il; Yoo, Hyung Keun; Choi, Jae Don; Lee, Byung Il; Kim, Jung Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
1994-07-01
During the third year of the project the development of TASS 1.0 code has been completed and validated its capability in applying for the licensing transient analyses of the Westinghouse and CE type operating reactors as well as the PWR reactors under construction in Korea. The validation of the TASS 1.0 code has been achieved through the comparison calculations of the YGN-3/4 FSAR transients, Kori-3 loss of AC power transient, plant data, Kori-4 load rejection and YGN-3 startup test data as well as the BETHSY loop steam generator tube rupture test data. TASS 1.0 calculation agrees well with the best estimate RELAP5/MOD 3.1 calculation for the YGN-3/4 FASR transients and shows its capability in simulating plant transient and startup data as well as the thermal hydraulic transient test data. Topical reports on TASS 1.0 code have been prepared and will be submitted to Korea Institute of Nuclear Safety for its licensing application to Westinghouse and CE type PWR transient analyses. The development of TASS 2.0 code has been head started in this year to timely utilize the TASS 2.0 code for the KNGR design certification. 65 figs, 30 tabs, 44 refs. (Author).
Transient Diagnosis and Prognosis for Secondary System in Nuclear Power Plants
Directory of Open Access Journals (Sweden)
Sangjun Park
2016-10-01
Full Text Available This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs, because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA. This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.
Transient diagnosis and prognosis for secondary system in nuclear power plants
Energy Technology Data Exchange (ETDEWEB)
Park, Sang Jin; Park, Jin Kyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Heo, Gyun Young [Dept. of Nuclear Engineering, Kyung Hee University, Yongin (Korea, Republic of)
2016-10-15
This paper introduces the development of a transient monitoring system to detect the early stage of a transient, to identify the type of the transient scenario, and to inform an operator with the remaining time to turbine trip when there is no operator's relevant control. This study focused on the transients originating from a secondary system in nuclear power plants (NPPs), because the secondary system was recognized to be a more dominant factor to make unplanned turbine-generator trips which can ultimately result in reactor trips. In order to make the proposed methodology practical forward, all the transient scenarios registered in a simulator of a 1,000 MWe pressurized water reactor were archived in the transient pattern database. The transient patterns show plant behavior until turbine-generator trip when there is no operator's intervention. Meanwhile, the operating data periodically captured from a plant computer is compared with an individual transient pattern in the database and a highly matched section among the transient patterns enables isolation of the type of transient and prediction of the expected remaining time to trip. The transient pattern database consists of hundreds of variables, so it is difficult to speedily compare patterns and to draw a conclusion in a timely manner. The transient pattern database and the operating data are, therefore, converted into a smaller dimension using the principal component analysis (PCA). This paper describes the process of constructing the transient pattern database, dealing with principal components, and optimizing similarity measures.
Ohmori, Shuichi; Narabayashi, Tadashi; Mori, Michitsugu
A steam injector (SI) is a simple, compact and passive pump and also acts as a high-performance direct-contact compact heater. This provides SI with capability to serve also as a direct-contact feed-water heater that heats up feed-water by using extracted steam from turbine. Our technology development aims to significantly simplify equipment and reduce physical quantities by applying "high-efficiency SI", which are applicable to a wide range of operation regimes beyond the performance and applicable range of existing SIs and enables unprecedented multistage and parallel operation, to the low-pressure feed-water heaters and emergency core cooling system of nuclear power plants, as well as achieve high inherent safety to prevent severe accidents by keeping the core covered with water (a severe accident-free concept). This paper describes the results of the scale model test, and the transient analysis of SI-driven passive core injection system (PCIS).
Institute of Scientific and Technical Information of China (English)
李峰; 李威; 薛峰; 施涛
2011-01-01
Focusing on the system stability of large-scale photovoltaic (PV) plants connected to the grid, this paper establishes a complete electromechanical transient model of grid-connected PV plant on FASTEST (fast analysis of stability using the extended equal area criterion and simulation technologies, a power system transient security quantitative analysis software). Based on FASTEST's unique transient security quantitative analysis, simulations are conducted for two typical cases: the PV plant was covered by cloud, and disturbance occurred on the system side. Studies are conducted to analyze the different impacts of the PV pant and the conventional power plant on the grid operation in terms of the system transient angle stability, transient voltage stability and transient frequency stability. The results show that, with the PV plant connected to the grid, the system transient frequency stability is most severely affected. Compared with a synchronous generator with excitation and governor system, the PV plant has a more remarkable transient response when a fault occurs on the grid side.%在电力系统暂态安全定量分析软件平台FASTEST(Fast Analysis of Stability using the Extended equal area criterion and Simulation Technologies)上以研究规模化光伏电站接入系统后的稳定性分析为目的,建立了一个完整而且适合系统安全稳定分析的并网光伏电站机电暂态模型.基于FASTEST特有的暂态稳定量化分析功能,对并网光伏电站被浮云遮挡和系统侧发生扰动这2种典型情况进行仿真分析,从对系统暂态功角稳定性、暂态电压稳定性和暂态频率稳定性的影响的角度,探讨光伏电站与常规电源在影响电网运行特性方面的区别.结果表明,光伏电站并网后对系统暂态频率稳定性影响最为严重,相比较于带有励磁和调速系统的同步发电机,光伏电站在网侧故障时的暂态响应特性更为剧烈.
Transient stability analysis of a distribution network with distributed generators
Xyngi, I.; Ishchenko, A.; Popov, M.; Van der Sluis, L.
2009-01-01
This letter describes the transient stability analysis of a 10-kV distribution network with wind generators, microturbines, and CHP plants. The network being modeled in Matlab/Simulink takes into account detailed dynamic models of the generators. Fault simulations at various locations are investigat
Computer Aided Transient Stability Analysis
Directory of Open Access Journals (Sweden)
Nihad M. Al-Rawi
2007-01-01
Full Text Available A program for handling and improving the transient stability of the Iraqi Super Grid electrical network was developed. The idea was demonstrated by applying it to the outages of the main generating units. The methodology was built upon a state of increasing power transfer through the healthy portion of network during disturbances. There were three parts concerned; the first part was the developing of the load flow program using fast decoupled method and the transient stability program using Modified Eulers method in the step by step solution, the second part was the engagement between the two programs, the third part was the application of the new program on the Iraqi supper grid network (400 kV.
Prony Analysis for Power System Transient Harmonics
Directory of Open Access Journals (Sweden)
Qi Li
2007-01-01
Full Text Available Proliferation of nonlinear loads in power systems has increased harmonic pollution and deteriorated power quality. Not required to have prior knowledge of existing harmonics, Prony analysis detects frequencies, magnitudes, phases, and especially damping factors of exponential decaying or growing transient harmonics. In this paper, Prony analysis is implemented to supervise power system transient harmonics, or time-varying harmonics. Further, to improve power quality when transient harmonics appear, the dominant harmonics identified from Prony analysis are used as the harmonic reference for harmonic selective active filters. Simulation results of two test systems during transformer energizing and induction motor starting confirm the effectiveness of the Prony analysis in supervising and canceling power system transient harmonics.
Transient loads analysis for space flight applications
Thampi, S. K.; Vidyasagar, N. S.; Ganesan, N.
1992-01-01
A significant part of the flight readiness verification process involves transient analysis of the coupled Shuttle-payload system to determine the low frequency transient loads. This paper describes a methodology for transient loads analysis and its implementation for the Spacelab Life Sciences Mission. The analysis is carried out using two major software tools - NASTRAN and an external FORTRAN code called EZTRAN. This approach is adopted to overcome some of the limitations of NASTRAN's standard transient analysis capabilities. The method uses Data Recovery Matrices (DRM) to improve computational efficiency. The mode acceleration method is fully implemented in the DRM formulation to recover accurate displacements, stresses, and forces. The advantages of the method are demonstrated through a numerical example.
Power System Transients Analysis by Wavelet Transforms
Institute of Scientific and Technical Information of China (English)
陈维荣; 宋永华; 赵蔚
2002-01-01
In contrast to Fourier transform, wavelet transform is especially suitable for transient analysis because of its time-frequency characteristics with automatically-adjusted window lengths. Research shows that wavelet transform is one of the most powerful tools for power system transient analysis. The basic ideas of wavelet transform are presented in the paper together with several power system applications. It is clear that wavelet transform has some clear advantages over other transforms in detecting, analyzing, and identifying various types of power system transients.
High-speed simulation of transients in nuclear power plants
Energy Technology Data Exchange (ETDEWEB)
Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.
1984-01-01
A combination of advanced modeling techniques and modern, special-purpose peripheral minicomputer technology is presented which affords realistic predictions of plant transient and severe off-normal events in LWR power plants through on-line simulations at a speed ten times greater than actual process speeds. Results are shown for a BWR plant simulation. Results are shown to demonstrate computing capacity, accuracy, and speed. Simulation speeds have been achieved which are 110 times larger than those of a CDC-7600 mainframe computer or ten times greater than real-time speed.
X33 Transient Liftoff Analysis
Peck, Jeff; Brunty, Joseph
2000-01-01
The successful design of a launch vehicle requires the careful characterization of the various loads the structure will experience over its lifetime. Many of the most demanding load environments occur during the launch/ascent phase of a mission, typically defined as the point of engine start through engine cut off. One of the critical events during the launch phase is the liftoff event. This event imparts high loads on the vehicle due to transient events such as thrust build-up and vehicle release. This paper describes the theory and procedures used to calculate structural loads due to the liftoff event for the Lockheed-Martin X33 technology demonstrator vehicle. These procedures were developed at NASA's Marshall Space Flight Center and verified previously on other advanced launch system concepts and the Space Shuttle system.
Pressurization transient analyses of the Lungmen ABWR plant using RETRAN-02
Energy Technology Data Exchange (ETDEWEB)
Tzang, Y.-C., E-mail: yctzang@aec.gov.t [National Tsing Hua University, Department of Engineering and System Science, Taiwan (China); Chiang, R.-F., E-mail: u807204@taipower.com.t [National Tsing Hua University, Department of Engineering and System Science, Taiwan, ROC (China); Yuan, Y.-R., E-mail: ryyuann@iner.gov.t [Engineer of Institute of Nuclear Energy Research Atomic Energy Council, Taiwan (China); Ferng, Y.-M., E-mail: ymferng@ess.nthu.edu.t [National Tsing Hua University, Department of Engineering and System Science, Taiwan (China); Pei, B.-S., E-mail: bspei@faculty.nthu.edu.t [National Tsing Hua University, Department of Engineering and System Science, Taiwan (China)
2010-04-15
The two limiting pressurization transient cases for the Lungmen ABWR plant: (1) Load Rejection with No Bypass and (2) Single Control Valve Closure in Fast Closure Mode, have been analyzed using the RETRAN-02 analysis model, which is independent of the model used by the NSSS vendor. The calculation results have been compared with those shown in the Lungmen FSAR. In general, the comparison shows that the transient response of key system parameters agrees well with the FSAR results, including those relating to core power, core inlet flow, system pressure, core inlet enthalpy, steam flow rate, feedwater flow rate, reactor water level, etc. Based on this, it is expected that the RETRAN-02 model developed in this study can be employed to support the operational transient analysis if the model is benchmarked further with the appropriate data, e.g., the Lungmen plant power test data, etc.
Buschmann, Henrik
2016-01-01
The continuing analysis of plant cell division will require additional protein localization studies. This is greatly aided by GFP-technology, but plant transformation and the maintenance of transgenic lines can present a significant technical bottleneck. In this chapter I describe a method for the Agrobacterium-mediated genetic transformation of tobacco BY-2 cells. The method allows for the microscopic analysis of fluorescence-tagged proteins in dividing cells in within 2 days after starting a coculture. This transient transformation procedure requires only standard laboratory equipment. It is hoped that this rapid method would aid researchers conducting live-cell localization studies in plant mitosis and cytokinesis.
Transients in VSC-HVDC connected offshore wind power plant
DEFF Research Database (Denmark)
El-Khatib, Walid Ziad; Schwartzberg, D.; Arana Aristi, I.;
2015-01-01
The focus of this paper is transient phenomena in VSC-HVDC connected offshore wind power plants (WPPs). With the help of a case study modelled in PSCAD simulation software, energisation events are analysed in the time domain. A comparison with more well-known results obtained at energisation of AC...... connected WPPs indicates that significant differences arise as the energy involved in the switching event increases, due to the presence of the HVDC converter control. The influence of the offshore HVDC converter control gain in the most critical cases is assessed empirically and explained qualitatively....
Energy Technology Data Exchange (ETDEWEB)
Kasahara, Naoto [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center; Jinbo, Masakazu [Toshiba Co., Tokyo (Japan); Hosogai, Hiromi [Joyo Industry Co., Ltd., Tokai, Ibaraki (Japan)
2002-09-01
This study proposes a mitigation method of thermal transient loads in fast reactor components by utilizing relationships among plant system parameters and resulting thermal stresses. Conventional design procedure against thermal transient loads has two independent steps: thermal hydraulic analysis to determine conservative thermal transient conditions considering variation of the system parameters and structural analysis to check structural integrity under given conditions. On the other hand, a total analysis procedure of thermal hydraulic and structural phenomena can grasp the relationship among system parameters and thermal stresses. It enables the mitigation of thermal transient loads by adjusting system parameters. (author)
ENHANCED SEVERE TRANSIENT ANALYSIS FOR PREVENTION TECHNICAL PROGRAM PLAN
Energy Technology Data Exchange (ETDEWEB)
Gougar, Hans [Idaho National Laboratory
2014-09-01
This document outlines the development of a high fidelity, best estimate nuclear power plant severe transient simulation capability that will complement or enhance the integral system codes historically used for licensing and analysis of severe accidents. As with other tools in the Risk Informed Safety Margin Characterization (RISMC) Toolkit, the ultimate user of Enhanced Severe Transient Analysis and Prevention (ESTAP) capability is the plant decision-maker; the deliverable to that customer is a modern, simulation-based safety analysis capability, applicable to a much broader class of safety issues than is traditional Light Water Reactor (LWR) licensing analysis. Currently, the RISMC pathway’s major emphasis is placed on developing RELAP-7, a next-generation safety analysis code, and on showing how to use RELAP-7 to analyze margin from a modern point of view: that is, by characterizing margin in terms of the probabilistic spectra of the “loads” applied to systems, structures, and components (SSCs), and the “capacity” of those SSCs to resist those loads without failing. The first objective of the ESTAP task, and the focus of one task of this effort, is to augment RELAP-7 analyses with user-selected multi-dimensional, multi-phase models of specific plant components to simulate complex phenomena that may lead to, or exacerbate, severe transients and core damage. Such phenomena include: coolant crossflow between PWR assemblies during a severe reactivity transient, stratified single or two-phase coolant flow in primary coolant piping, inhomogeneous mixing of emergency coolant water or boric acid with hot primary coolant, and water hammer. These are well-documented phenomena associated with plant transients but that are generally not captured in system codes. They are, however, generally limited to specific components, structures, and operating conditions. The second ESTAP task is to similarly augment a severe (post-core damage) accident integral analyses code
Energy Technology Data Exchange (ETDEWEB)
Lima, Marcio Poubel; Martins Junior, Laercio Lucena; Vanni, Enio Antonio; Machado, Marcio Dornellas; Moreira, Francisco Jose [ELETRONUCLEAR, Rio de Janeiro, RJ (Brazil); Alvim, Antonio Carlos M. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear
1999-11-01
The present work is part of several analyses under development in ELETRONUCLEAR/ COPPE-UFRJ to evaluate impacts on licensing bases and operating conditions of an increase in steam generator tube plugging for Angra 1 NPP. Total loss of reactor coolant flow uncontrolled boron dilution transients were initially analysed. The final results indicated that were no impacts on FSAR established margins, in case of 24% steam generator tube plugging. (author) 3 refs., 4 figs., 4 tabs.
Neural network recognition of nuclear power plant transients
Energy Technology Data Exchange (ETDEWEB)
Bartlett, E.B.; Danofsky, R.; Adams, J.; AlJundi, T.; Basu, A.; Dhanwada, C.; Kerr, J.; Kim, K.; Lanc, T.
1993-02-23
The objective of this report is to describe results obtained during the first year of funding that will lead to the development of an artificial neural network (ANN) fault - diagnostic system for the real - time classification of operational transients at nuclear power plants. The ultimate goal of this three-year project is to design, build, and test a prototype diagnostic adviser for use in the control room or technical support center at Duane Arnold Energy Center (DAEC); such a prototype could be integrated into the plant process computer or safety - parameter display system. The adviser could then warn and inform plant operators and engineers of plant component failures in a timely manner. This report describes the work accomplished in the first of three scheduled years for the project. Included herein is a summary of the first year's results as, well as individual descriptions of each of the major topics undertaken by the researchers. Also included are reprints of the articles written under this funding as well as those that were published during the funded period.
Integrated control system responses during load rejection transient for Lungmen ABWR Plant
Energy Technology Data Exchange (ETDEWEB)
Ma Shaoshih, E-mail: ssma@iner.gov.tw [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2, Kuang Fu Rd., HsinChu City 30013, Taiwan (China); Institute of Nuclear Energy Research, Atomic Energy Council, ROC, P.O. Box 3-3, Lungtan, Taoyuan 32546, Taiwan (China); Shih Chunkuan [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2, Kuang Fu Rd., HsinChu City 30013, Taiwan (China); Yuann Yngruey [Institute of Nuclear Energy Research, Atomic Energy Council, ROC, P.O. Box 3-3, Lungtan, Taoyuan 32546, Taiwan (China)
2011-07-15
Highlights: > The Lungmen RETRAN model was used to evaluate the load rejection with bypass start-up test. > The purpose is to verify the capability of the plant withstand a load rejection without scram. > The responses of the control systems are important to help mitigate the transient impact. > The analysis show that the reactor is not scrammed due to the proper responses of the control systems. > As long as bypass capacity functions in time, there is no significant pressurization in transient. - Abstract: The RETRAN model of Lungmen ABWR Plant was used to evaluate the load rejection with bypass transient of the start-up test program. There are three major control systems implemented in Lungmen RETRAN Model, including recirculation flow control, feedwater control, steam bypass and pressure control system. The responses of the control systems are important to help the reactor operate smoothly in the test, and credited to mitigate the transient impact. A brief description about the Lungmen RETRAN Model and the design feature of control systems is included in this article. The predicted analysis of load rejection test was conducted by using RETRAN-3D code to verify the dynamic responses of the reactor and control systems to protective trips in the generator, and also to demonstrate the capability of the plant to withstand against a generator load rejection without reactor scram. The analysis results show that the reactor has not been scrammed due to the proper control system responses, and sustained stable operation under the condition of the minimum station house load. The sensitivity studies show that there will be no significant pressurization in load rejection transient as long as activating bypass capacity functions in time. While, the sensitivity study cases of other settings in the mitigation facilities have no outstanding impact on the system response.
Directory of Open Access Journals (Sweden)
Bratić Ana M.
2010-01-01
Full Text Available Gene expression is mediated by DNA sequences directly upstream from the coding sequences, recruited transcription factors and RNA polymerase in a spatially-defined manner. Understanding promoter strength and regulation would enhance our understanding of gene expression. The goal of this study was to develop a fast, efficient and reliable method for testing basal promoter activity and identifying core sequences within its pollen specific elements. In this paper we examined the functionality of buckwheat metallothionein promoter by a histochemical GUS assay in two transient expression systems: BY2 cells and pollen grains. Strong promoter activity was observed in both systems.
GTRAN- TRANSIENT ANALYSIS OF GAS PIPING SYSTEMS
TROVILLION T A
1994-01-01
The GTRAN program was developed to solve transient, as well as steady state, problems for gas piping systems. GTRAN capabilities allow for the analysis of a variety of system configurations and components. These include: multiple pipe junctions; valves that change position with time; fixed restrictions (orifices, manual valves, filters, etc.); relief valves; constant pressure sources; and heat transfer for insulated piping and piping subjected to free or forced convection. In addition, boundary conditions can be incorporated to simulate specific components. The governing equations of GTRAN are the one-dimensional transient gas dynamic equations. The three equations for pressure, velocity, and density are reduced to numerical equations using an implicit Crank-Nicholson finite difference technique. Input to GTRAN includes a description of the piping network, the initial conditions, and any events (e.g. valve closings) occuring during the period of analysis. Output includes pressure, velocity, and density versus time. GTRAN is written in FORTRAN 77 for batch execution and has been implemented on a DEC VAX series computer. GTRAN was developed in 1983.
Thermal transient analysis applied to horizontal wells
Energy Technology Data Exchange (ETDEWEB)
Duong, A.N. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada)
2008-10-15
Steam assisted gravity drainage (SAGD) is a thermal recovery process used to recover bitumen and heavy oil. This paper presented a newly developed model to estimate cooling time and formation thermal diffusivity by using a thermal transient analysis along the horizontal wellbore under a steam heating process. This radial conduction heating model provides information on the heat influx distribution along a horizontal wellbore or elongated steam chamber, and is therefore important for determining the effectiveness of the heating process in the start-up phase in SAGD. Net heat flux estimation in the target formation during start-up can be difficult to measure because of uncertainties regarding heat loss in the vertical section; steam quality along the horizontal segment; distribution of steam along the wellbore; operational conditions; and additional effects of convection heating. The newly presented model can be considered analogous to pressure transient analysis of a buildup after a constant pressure drawdown. The model is based on an assumption of an infinite-acting system. This paper also proposed a new concept of a heating ring to measure the heat storage in the heated bitumen at the time of testing. Field observations were used to demonstrate how the model can be used to save heat energy, conserve steam and enhance bitumen recovery. 18 refs., 14 figs., 2 appendices.
Energy Technology Data Exchange (ETDEWEB)
Oliveira, Iona M.S. de; Schirru, Roberto, E-mail: ioliveira@con.ufrj.br, E-mail: schirru@lmp.ufrj.br [Coordenacoa dos Programas de Pos-Graduacao em Engenharia (UFRJ/PEN/COPPE), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear
2011-07-01
The identification of possible transients in a nuclear power plant is a highly relevant problem. This is mainly due to the fact that the operation of a nuclear power plant involves a large number of state variables whose behaviors are extremely dynamic. In risk situations, besides the huge cognitive overload that operators are submitted to, there is also the problem related with the considerable decrease in the effective time for correct decision making. To minimize these problems and help operators to make the corrective actions in due time, this paper presents a new contribution in this area and introduces an experimental transient identification system based exclusively on the abilities of the Discrete Binary Artificial Bee Colony (DBABC) algorithm to find the best centroid positions that correctly identifies a transient in a nuclear power plant. The DBABC is a reworking of the Artificial Bee Colony (ABC) algorithm which presents the advantage of operating in both continuous and discrete search spaces. Through the analysis of experimental results, the effective performance of the proposed DBABC algorithm is shown against some well known best performing algorithms from the literature. (author)
Transient Analysis of a Magnetic Heat Pump
Schroeder, E. A.
1985-01-01
An experimental heat pump that uses a rare earth element as the refrigerant is modeled using NASTRAN. The refrigerant is a ferromagnetic metal whose temperature rises when a magnetic field is applied and falls when the magnetic field is removed. The heat pump is used as a refrigerator to remove heat from a reservoir and discharge it through a heat exchanger. In the NASTRAN model the components modeled are represented by one-dimensional ROD elements. Heat flow in the solids and fluid are analyzed. The problem is mildly nonlinear since the heat capacity of the refrigerant is temperature-dependent. One simulation run consists of a series of transient analyses, each representing one stroke of the heat pump. An auxiliary program was written that uses the results of one NASTRAN analysis to generate data for the next NASTRAN analysis.
A predictive controller based on transient simulations for controlling a power plant
Svingen, B.
2016-11-01
A predictive governor based on an embedded, online transient simulation was commissioned at Tonstad power plant in Norway in December 2014. This governor controls each individual turbine governor by feeding them modified setpoints. Tonstad power plant consists of 4 × 160 MW + 1 × 320 MW high head Francis turbines. With a yearly production of 3888 GWh, it is the largest in Norway. The plant is a typical high head Norwegian plant with very long tunnels and correspondingly active dynamic behaviour. This new governor system continuously simulates the entire plant, and appropriate actions are taken automatically by special algorithms. The simulations are based on the method of characteristics (MOC). The governing system has been in full operational mode since December 19 2014. The testing period also included special acceptance tests to be able to deliver FRR, both on the Nordic grid and on DC cable to Denmark. Although in full operational mode, this system is still a prototype under constant development. It shows a new way of using transient analysis that may become increasingly important in the future with added power from un-regulated sources such as wind, solar and bio.
Energy Technology Data Exchange (ETDEWEB)
Llopis, C.; Casals, A. [Asociacion Nuclear Vandellos, Madrid (Spain); Perez, J.; Mendizabal, R. [Consejo de Seguridad Nuclear, Madrid (Spain)
1993-12-01
The Consejo de Seguridad Nuclear (CSN) and the Asociacion Nuclear Vandellos (ANV) have developed a model of Vandellos II Nuclear Power Plant. The ANV collaboration consisted in the supply of design and actual data, the cooperation in the simulation of the control systems and other model components, as well as in the results analysis. The obtained model has been assessed against the following transients occurred in plant: A trip from the 100% power level (CSN); a load rejection from 100% to 50% (CSN); a load rejection from 75% to 65% (ANV); and, a feedwater turbopump trip (ANV). This copy is a report of the feedwater turbopump trip transient simulation. This transient actually occurred in the plant on June 19, 1989.
Energy Technology Data Exchange (ETDEWEB)
Hanine, M. [Laboratoire Electronique Microtechnologie et Instrumentation (LEMI), University of Rouen, 76821 Mont Saint Aignan (France)]. E-mail: Mounir.Hanine@univ-rouen.fr; Masmoudi, M. [Laboratoire Electronique Microtechnologie et Instrumentation (LEMI), University of Rouen, 76821 Mont Saint Aignan (France); Marcon, J. [Laboratoire Electronique Microtechnologie et Instrumentation (LEMI), University of Rouen, 76821 Mont Saint Aignan (France)
2004-12-15
In this paper, a reliable procedure, which allows a fine as well as a robust analysis of the deep defects in semiconductors, is detailed. In this procedure where capacitance transients are considered as multiexponential and corrupted with Gaussian noise, our new method of analysis, the Levenberg-Marquardt deep level transient spectroscopy (LM-DLTS) is associated with two other high-resolution techniques, i.e. the Matrix Pencil which provides an approximation of exponential components contained in the capacitance transients and Prony's method recently revised by Osborne in order to set the initial parameters.
Qualitative diagnosis for transients analysis on nuclear reactors
Energy Technology Data Exchange (ETDEWEB)
Lorre, J.P.; Dorlet, E.; Evrard, J.M.
1995-12-31
One of the major aims of an intelligent monitoring system, is the supervision task which assist the operator in understanding what occurs on a process. Failures hypotheses must be located and the inferring process must be explained. This paper demonstrate a second generation expert system (SEXTANT) decided to the transients analysis on PWR nuclear reactors. This system detects failures by simulating the process with a numerical model. A diagnosis module uses an even graph built from a causal graph model of the plant to generate hypotheses, and a numerical model to validate these hypotheses. Hypotheses are stored into scenarios which are concurrent possible interpretations of the process evolution. The approach is illustrated by an application for the analysis of the house load operation on a pressurized water reactor. (authors). 9 refs., 10 figs.
Transient Stability Analysis Using Transmission Line Measurement
Institute of Scientific and Technical Information of China (English)
蔡国伟; 程浩忠; 陈家荣; 王承民
2004-01-01
The novel quantitative assessment method using transmission line measurement was developed. A new style of stability criterion was suggested which is based on the line measurement. The stability indices for lines,cutsets and power system according to features of transient energy in the lines were given, which not only provide a reliable and accurate assessment of the transient stability of power system, but also can be used to assess the effect of lines and cutsets on the transient stability and identify the weak transmission segment. Examples were presented by simulation on the IEEE-39 buses test system.
Directory of Open Access Journals (Sweden)
José Francisco de Carvalho Gonçalves
2010-03-01
odorata (Aublet Willd exposed to two light environments (shade and sunlight. The experiment was carried in Manaus-AM, Brazil (3º8'S, 59º52'W. Analysis of chlorophyll a fluorescence transients were obtained in intact and healthy leaves between 10:00 to 12:00 am. The curve OJIP indicated that the species high irradiance exposed presented photoinhibition after 45 days of experiment. Andiroba and cumaru plants exposed to sunlight exhibited low values of TRo/ABS (7.17 and 20.4%, respectively, ETo/TRo (14.5 and 27.2%, respectively and ETo/ABS (20.6 and 42.2%, respectively and high values of DIo/ABS (26.9 and 43.0%, respectively, compared with plants exposed to the shadow with 45 days of experiment. As for phenomenological flux, most of the parameters, low values were observed for both exposed species in the sunlight. Andiroba and cumaru plants exposed in the sunlight exhibited low values of PIABS (63.3 and 78.7%, respectively compared with exposed plants to the shadow at the end of the experiment. Although the species have suffered with the stress for high irradiance andiroba specie presented better performance than cumaru being indicated for use in production planting or degraded area restoration.
Computer Models for IRIS Control System Transient Analysis
Energy Technology Data Exchange (ETDEWEB)
Gary D. Storrick; Bojan Petrovic; Luca Oriani
2007-01-31
This report presents results of the Westinghouse work performed under Task 3 of this Financial Assistance Award and it satisfies a Level 2 Milestone for the project. Task 3 of the collaborative effort between ORNL, Brazil and Westinghouse for the International Nuclear Energy Research Initiative entitled “Development of Advanced Instrumentation and Control for an Integrated Primary System Reactor” focuses on developing computer models for transient analysis. This report summarizes the work performed under Task 3 on developing control system models. The present state of the IRIS plant design – such as the lack of a detailed secondary system or I&C system designs – makes finalizing models impossible at this time. However, this did not prevent making considerable progress. Westinghouse has several working models in use to further the IRIS design. We expect to continue modifying the models to incorporate the latest design information until the final IRIS unit becomes operational. Section 1.2 outlines the scope of this report. Section 2 describes the approaches we are using for non-safety transient models. It describes the need for non-safety transient analysis and the model characteristics needed to support those analyses. Section 3 presents the RELAP5 model. This is the highest-fidelity model used for benchmark evaluations. However, it is prohibitively slow for routine evaluations and additional lower-fidelity models have been developed. Section 4 discusses the current Matlab/Simulink model. This is a low-fidelity, high-speed model used to quickly evaluate and compare competing control and protection concepts. Section 5 describes the Modelica models developed by POLIMI and Westinghouse. The object-oriented Modelica language provides convenient mechanisms for developing models at several levels of detail. We have used this to develop a high-fidelity model for detailed analyses and a faster-running simplified model to help speed the I&C development process
Lightning transient analysis in wind turbine blades
DEFF Research Database (Denmark)
Candela Garolera, Anna; Holbøll, Joachim; Madsen, Søren Find
2013-01-01
The transient behavior of lightning surges in the lightning protection system of wind turbine blades has been investigated in this paper. The study is based on PSCAD models consisting of electric equivalent circuits with lumped and distributed parameters involving different lightning current...
Application of a Scalable Plant Transient Gene Expression Platform for Malaria Vaccine Development
Spiegel, Holger; Boes, Alexander; Voepel, Nadja; Beiss, Veronique; Edgue, Gueven; Rademacher, Thomas; Sack, Markus; Schillberg, Stefan; Reimann, Andreas; Fischer, Rainer
2015-01-01
Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route toward the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification, and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs, and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here, we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility, and stability using fluorescent fusion proteins. Our
Application of a Scalable Plant Transient Gene Expression Platform for Malaria Vaccine Development.
Spiegel, Holger; Boes, Alexander; Voepel, Nadja; Beiss, Veronique; Edgue, Gueven; Rademacher, Thomas; Sack, Markus; Schillberg, Stefan; Reimann, Andreas; Fischer, Rainer
2015-01-01
Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route toward the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification, and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs, and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here, we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility, and stability using fluorescent fusion proteins. Our
Application of a scalable plant transient gene expression platform for malaria vaccine development
Directory of Open Access Journals (Sweden)
Holger eSpiegel
2015-12-01
Full Text Available Despite decades of intensive research efforts there is currently no vaccine that provides sustained sterile immunity against malaria. In this context, a large number of targets from the different stages of the Plasmodium falciparum life cycle have been evaluated as vaccine candidates. None of these candidates has fulfilled expectations, and as long as we lack a single target that induces strain-transcending protective immune responses, combining key antigens from different life cycle stages seems to be the most promising route towards the development of efficacious malaria vaccines. After the identification of potential targets using approaches such as omics-based technology and reverse immunology, the rapid expression, purification and characterization of these proteins, as well as the generation and analysis of fusion constructs combining different promising antigens or antigen domains before committing to expensive and time consuming clinical development, represents one of the bottlenecks in the vaccine development pipeline. The production of recombinant proteins by transient gene expression in plants is a robust and versatile alternative to cell-based microbial and eukaryotic production platforms. The transfection of plant tissues and/or whole plants using Agrobacterium tumefaciens offers a low technical entry barrier, low costs and a high degree of flexibility embedded within a rapid and scalable workflow. Recombinant proteins can easily be targeted to different subcellular compartments according to their physicochemical requirements, including post-translational modifications, to ensure optimal yields of high quality product, and to support simple and economical downstream processing. Here we demonstrate the use of a plant transient expression platform based on transfection with A. tumefaciens as essential component of a malaria vaccine development workflow involving screens for expression, solubility and stability using fluorescent fusion
Plant analyzer for high-speed interactive simulation of BWR power plant transients
Energy Technology Data Exchange (ETDEWEB)
Cheng, H.S.; Lekach, S.V.; Mallen, A.N.; Wulff, W.; Cerbone, R.J.
1984-04-01
A combination of advanced modeling techniques and modern, special-purpose peripheral minicomputer technology is presented which affords realistic predictions of plant transient and severe off-normal events in LWR power plants through on-line simulations at a speed ten times faster than actual process speeds. Results are shown for a BWR plant simulation. The mathematical models account for nonequilibrium, nonhomogeneous two-phase flow effects in the coolant, for acoustical effects in the steam line and for the dynamics of the recirculation loop and feedwater train. Point kinetics incorporate reactivity feedback due to void fraction, fuel temperature, coolant temperature, and boron concentration. Control systems and trip logic are simulated for the nuclear steam supply system. The AD10 of Applied Dynamics International is the special-purpose peripheral processor. It is specifically designed for high-speed digital system simulation, accommodates hardware (instrumentation) in the input/output loop, and operates interactively on-line, like an analog computer. Results are shown to demonstrate computing capacity, accuracy, and speed. Simulation speeds have been achieved which are orders of magnitude faster than those of a CDC-7600 mainframe computer or ten times faster than real-time speed.
Design and Transient Analysis of Passive Safety Cooling Systems for Advanced Nuclear Reactors
Galvez, Cristhian
2011-01-01
The Pebble Bed Advanced High Temperature Reactor (PB-AHTR) is a pebble fueled, liquid salt cooled, high temperature nuclear reactor design that can be used for electricity generation or other applications requiring the availability of heat at elevated temperatures. A stage in the design evolution of this plant requires the analysis of the plant during a variety of potential transients to understand the primary and safety cooling system response. This study focuses on the performance of the pa...
Ignition transient analysis of solid rocket motor
Han, Samuel S.
1991-01-01
Measurement data on the performance of Space Shuttle Solid Rocket Motor show wide variations in the head-end pressure changes and the total thrust build-up during the ignition transient periods. To analyze the flow and thermal behavior in the tested solid rocket motors, a 1-dimensional, ideal gas flow model via the SIMPLE algorithm was developed. Numerical results showed that burning patterns in the star-shaped head-end segment of the propellant and the erosive burning rate are two important factors controlling the ignition transients. The objective of this study is to extend the model to include the effects of aluminum particle commonly used in solid propellants. To treat the effects of aluminum-oxide particles in the combustion gas, conservation of mass, momentum, and energy equations for the particles are added in the numerical formulation and integrated by an inter-phase-slip algorithm.
Convected transient analysis for large space structures maneuver and deployment
Housner, J.
1984-01-01
Convected-transient analysis techniques in the finite-element method are used to investigate the deployment and maneuver of large spacecraft structures with multiple-member flexible trusses and frames. Numerical results are presented for several sample problems.
Adaptive Nodal Transport Methods for Reactor Transient Analysis
Energy Technology Data Exchange (ETDEWEB)
Thomas Downar; E. Lewis
2005-08-31
Develop methods for adaptively treating the angular, spatial, and time dependence of the neutron flux in reactor transient analysis. These methods were demonstrated in the DOE transport nodal code VARIANT and the US NRC spatial kinetics code, PARCS.
Transient Analysis of X-34 Pressurization System
Hedayat, A.; Knight, K. C.; Champion, R. H., Jr.
1998-01-01
Two transient operational modes of the X-34 pressurization system were analyzed using the ROCket Engine Transition Simulation (ROCETS) program. The first operational mode considers the normal operation. For the engine burn period, the required helium mass and pressure of each propellant tank were calculated. In the second case, the possibility of failure of the pressurization system solenoid valves, its consequence on the over-pressurization, and simultaneous operation of pressurization and vent/relief systems were evaluated.
A New Adaptive Mother Wavelet for Electromagnetic Transient Analysis
Guillén, Daniel; Idárraga-Ospina, Gina; Cortes, Camilo
2016-01-01
Wavelet Transform (WT) is a powerful technique of signal processing, its applications in power systems have been increasing to evaluate power system conditions, such as faults, switching transients, power quality issues, among others. Electromagnetic transients in power systems are due to changes in the network configuration, producing non-periodic signals, which have to be identified to avoid power outages in normal operation or transient conditions. In this paper a methodology to develop a new adaptive mother wavelet for electromagnetic transient analysis is proposed. Classification is carried out with an innovative technique based on adaptive wavelets, where filter bank coefficients will be adapted until a discriminant criterion is optimized. Then, its corresponding filter coefficients will be used to get the new mother wavelet, named wavelet ET, which allowed to identify and to distinguish the high frequency information produced by different electromagnetic transients.
Transient Temperature Analysis of Slab in Erdemir
Institute of Scientific and Technical Information of China (English)
(U)nal Camdali; Murat Tunc; Sedat Sisbot
2008-01-01
A transient thermal model was developed for slab furnaces in Eregli Iron and Steel Worlds (Erdemir) in Turkey and the model was solved using the FlexPDE computer program. This program uses the finite element method. Program codes were written to solve the temperature distribution of slabs that are put into furnace at 25℃ and removed at about 1 250℃. To obtain the optimum slab exit temperature variation, the necessary air temperature inside the furnace was calculated to be 1 390℃. The slab temperature versus time and the temperature variation inside the slab were depicted.
Plant data comparisons for Comanche Peak 1/2 main feedwater pump trip transient
Energy Technology Data Exchange (ETDEWEB)
Boatwright, W.J.; Choe, W.G; Hiltbrand, D.W. [TU Electric, Dallas, TX (United States)] [and others
1995-09-01
A RETRAN-02 MOD5 model of Comanche Peak Steam Electric Station was developed by TU Electric for the purpose of performing core reload safety analyses. In order to qualify this model, comparisons against plant transient data from a partial loss of main feedwater flow were performed. These comparisons demonstrated that good representations of the plant response could be obtained with RETRAN-02 and the user-developed models of the primary-to-secondary heat transfer and plant control systems.
Nonlinear transient analysis of joint dominated structures
Chapman, J. M.; Shaw, F. H.; Russell, W. C.
1987-01-01
A residual force technique is presented that can perform the transient analyses of large, flexible, and joint dominated structures. The technique permits substantial size reduction in the number of degrees of freedom describing the nonlinear structural models and can account for such nonlinear joint phenomena as free-play and hysteresis. In general, joints can have arbitrary force-state map representations but these are used in the form of residual force maps. One essential feature of the technique is to replace the arbitrary force-state maps describing the nonlinear joints with residual force maps describing the truss links. The main advantage of this replacement is that the incrementally small relative displacements and velocities across a joint are not monitored directly thereby avoiding numerical difficulties. Instead, very small and 'soft' residual forces are defined giving a numerically attractive form for the equations of motion and thereby permitting numerically stable integration algorithms. The technique was successfully applied to the transient analyses of a large 58 bay, 60 meter truss having nonlinear joints. A method to perform link testing is also presented.
Transients from Initial Conditions A Perturbative Analysis
Scoccimarro, R
1998-01-01
The standard procedure to generate initial conditions (IC) in numerical simulations is to use the Zel'dovich approximation (ZA). Although the ZA correctly reproduces the linear growing modes of density and velocity perturbations, non-linear growth is inaccurately represented because of the ZA failure to conserve momentum. This implies that it takes time for the actual dynamics to establish the correct statistical properties of density and velocity fields. We extend perturbation theory (PT) to include transients as non-linear excitations of decaying modes caused by the IC. We focus on higher-order statistics of the density contrast and velocity divergence, characterized by the S_p and T_p parameters. We find that the time-scale of transients is determined, at a given order p, by the spectral index n. The skewness factor S_3 (T_3) attains 10% accuracy only after a=6 (a=15) for n=0, whereas higher (lower) n demands more (less) expansion away from the IC. These requirements become much more stringent as p increas...
Transient Temperature Analysis for Industrial AC Arc Furnace Bottom
Institute of Scientific and Technical Information of China (English)
(U)nal (C)amdal1; Murat Tun(c)
2004-01-01
Heat losses from the furnaces depend on the design and size. The surface heat loss from the bottom of an industrial AC electric arc furnace (EAF) possesses an important fraction of overall losses. So in this study the transient temperature variation at the bottom of the EAF was investigated. The transient temperature analysis was carried out using MATLAB computer program. T=T(r, t) for different bottom lining layers was depicted.
Alternatives Analysis for the Resumption of Transient Testing Program
Energy Technology Data Exchange (ETDEWEB)
Lee Nelson
2013-11-01
An alternatives analysis was performed for resumption of transient testing. The analysis considered eleven alternatives – including both US international facilities. A screening process was used to identify two viable alternatives from the original eleven. In addition, the alternatives analysis includes a no action alternative as required by the National Environmental Policy Act (NEPA). The alternatives considered in this analysis included: 1. Restart the Transient Reactor Test Facility (TREAT) 2. Modify the Annular Core Research Reactor (ACRR) which includes construction of a new hot cell and installation of a new hodoscope. 3. No Action
ECCS flow verification to support transient analysis
Energy Technology Data Exchange (ETDEWEB)
Kovach, C.; Jacobs, R.H.; Ballard, J.E. [Commonwealth Edison Co., Chicago, IL (United States). Nuclear Fuel Services Dept.
1994-12-31
The RETRAN code has been used to develop a model of the Emergency Core Cooling System (ECCS). The model was developed in order to provide conservative injection flow data to be used in various LOCA and non-LOCA analyses and evaluations and to ensure that ECCS pump runout does not occur. The analyses were also needed in order to address a number of ECCS performance issues identified by Westinghouse. These issues include how previous analyses modeled miniflow, RCP seal injection, ECCS branch line resistance, pump suction boost during recirculation, injection line flow imbalances, and, of particular importance, ECCS flow measurement inaccuracies. In turn, these issues directly impact pump runout concerns, Technical Specification verification, and ECCS injection flow during transient conditions. The RETRAN ECCS model has proven to be quite versatile, easy to use, and requires only minimal information about the physical construction and performance of the ECCS system.
Analysis of nonlinear transient responses of piezoelectric resonators.
Hagiwara, Manabu; Takahashi, Seita; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki
2011-09-01
The electric transient response method is an effective technique to evaluate material constants of piezoelectric ceramics under high-power driving. In this study, we tried to incorporate nonlinear piezoelectric behaviors in the analysis of transient responses. As a base for handling the nonlinear piezoelectric responses, we proposed an assumption that the electric displacement is proportional to the strain without phase lag, which could be described by a real and constant piezoelectric e-coefficient. Piezoelectric constitutive equations including nonlinear responses were proposed to calculate transient responses of a piezoelectric resonator. The envelopes and waveforms of current and vibration velocity in transient responses observed in some piezoelectric ceramics could be fitted with the calculation including nonlinear responses. The procedure for calculation of mechanical quality factor Q(m) for piezoelectric resonators with nonlinear behaviors was also proposed.
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......The dynamics of structured plant populations in variable environments can be decomposed into the ‘asymptotic’ growth contributed by vital rates, and ‘transient’ growth caused by deviation from stable stage structure. We apply this framework to a large, global data base of longitudinal studies...... of projection matrix models for plant populations. We ask, what is the relative contribution of transient boom and bust to the dynamic trajectories of plant populations in stochastic environments? Is this contribution patterned by phylogeny, growth form or the number of life stages per population and per...
Improvements to the CONTINUE feature in transient analysis
Pamidi, P. R.
1989-01-01
The CONTINUE feature in transient analysis as implemented in the standard release of COSMIC/NASTRAN has inherent errors associated with it. As a consequence, the results obtained by a CONTINUEd restart run do not, in general, match the results that would be obtained in a single run without the CONTINUE feature. These inherent errors were eliminated by improvements to the restart logic that were developed by RPK Corporation and that are available on all RPK-supported versions of COSMIC/NASTRAN. These improvements ensure that the results of a CONTINUEd transient analysis run are the same as those of a non-CONTINUEd run. In addition, the CONTINUE feature was extended to transient analysis involving uncoupled modal equations. The improvements and enhancement were illustrated by examples.
THE WAVELET ANALYSIS METHOD ON THE TRANSIENT SIGNAL
Institute of Scientific and Technical Information of China (English)
吴淼
1996-01-01
Many dynamic signals of mining machines are transient, such as load signals when roadheader's cutting head being cut-in or cut-out and response signals produced by these loads. For these transient signals, the traditional Fourier analysis method is quite inadequate,The limitations of analysis, resolution by using Short-Time Fourier Transform (STFT) on them were discussed in this paper. Because of wavelet transform having the characteristics of flexible window and multiresolution analysis, we try to apply it to analyse these transientsignal. In order to give a pratical example,using D 18 wavelet and Mallat's tree algorithm with MATLAB, the discrete wavelet transform was calculated for the simulating response signals of a three-degree-of freedom vibration system when it was under impulse and random excitations. The results of the wavelet transform made clear its effectiveness and superiority in analysing transient signals of mining machines.
Transient Analysis of Hysteresis Queueing Model Using Matrix Geometric Method
Directory of Open Access Journals (Sweden)
Wajiha Shah
2011-10-01
Full Text Available Various analytical methods have been proposed for the transient analysis of a queueing system in the scalar domain. In this paper, a vector domain based transient analysis is proposed for the hysteresis queueing system with internal thresholds for the efficient and numerically stable analysis. In this system arrival rate of customer is controlled through the internal thresholds and the system is analyzed as a quasi-birth and death process through matrix geometric method with the combination of vector form Runge-Kutta numerical procedure which utilizes the special matrices. An arrival and service process of the system follows a Markovian distribution. We analyze the mean number of customers in the system when the system is in transient state against varying time for a Markovian distribution. The results show that the effect of oscillation/hysteresis depends on the difference between the two internal threshold values.
Energy Technology Data Exchange (ETDEWEB)
Kim, Ho Sik, E-mail: hskim25@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, In Hun, E-mail: nuclea@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); NO, Hee Cheon, E-mail: hcno@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jin, Hyung Gon, E-mail: gonijin@gmail.com [Korea Advanced Institute of Science and Technology (KAIST), Department of Nuclear and Quantum Engineering, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)
2013-06-15
Highlights: ► The GAMMA-T code was well validated through benchmark experiments. ► Based on the KAIST coupling scheme, the GTHTR300 + MED systems were made. ► Safety analysis was performed for overcooling and undercooling accidents. ► In all accidents, maximum peak fuel temperatures were well below than 1600 °C. ► In all accidents, the HTGR + MED system could be operated continuously. -- Abstracts: The nuclear desalination based on the high temperature gas-cooled reactor (HTGR) with gas turbomachinery and multi-effect distillation (MED) is attracting attention because the coupling system can utilize the waste heat of the nuclear power system for the MED desalination system. In previous work, KAIST proposed the new HTGR + MED coupling scheme, evaluated desalination performance, and performed cost analysis for the system. In this paper, in order to confirm the safety and the performance of the coupling system, we performed the transient analysis with GAMMA-T (GAs Multidimensional Multicomponent mixture Analysis–Turbomachinery) code for the KAIST HTGR + MED systems. The experimental benchmarks of GAMMA-T code were set up before the transient analysis for several accident scenarios. The GAMMA-T code was well validated against steady state and transient scenarios of the He–Water test loop such as changes in water mass flow rate and water inlet temperatures. Then, for transient analysis, the GTHTR300 was chosen as a reference plant. The GTHTR300 + MED systems were made, based on the KAIST HTGR + MED coupling scheme. Transient analysis was performed for three kinds of accidents scenarios: (1) loss of heat rejection through MED plant, (2) loss of heat rejection through heat sink, and (3) overcooling due to abnormal cold temperature of seawater. In all kinds of accident scenarios, maximum peak fuel temperatures were well below than the fuel failure criterion, 1600 °C and the GTHTR300 + MED system could be operated continuously and safely. Specially, in the
Code Coupling for Multi-Dimensional Core Transient Analysis
Energy Technology Data Exchange (ETDEWEB)
Park, Jin-Woo; Park, Guen-Tae; Park, Min-Ho; Ryu, Seok-Hee; Um, Kil-Sup; Lee Jae-Il [KEPCO NF, Daejeon (Korea, Republic of)
2015-05-15
After the CEA ejection, the nuclear power of the reactor dramatically increases in an exponential behavior until the Doppler effect becomes important and turns the reactivity balance and power down to lower levels. Although this happens in a very short period of time, only few seconds, the energy generated can be very significant and cause fuel failures. The current safety analysis methodology which is based on overly conservative assumptions with the point kinetics model results in quite adverse consequences. Thus, KEPCO Nuclear Fuel(KNF) is developing the multi-dimensional safety analysis methodology to mitigate the consequences of the single CEA ejection accident. For this purpose, three-dimensional core neutron kinetics code ASTRA, sub-channel analysis code THALES, and fuel performance analysis code FROST, which have transient calculation performance, were coupled using message passing interface (MPI). This paper presents the methodology used for code coupling and the preliminary simulation results with the coupled code system (CHASER). Multi-dimensional core transient analysis code system, CHASER, has been developed and it was applied to simulate a single CEA ejection accident. CHASER gave a good prediction of multi-dimensional core transient behaviors during transient. In the near future, the multi-dimension CEA ejection analysis methodology using CHASER is planning to be developed. CHASER is expected to be a useful tool to gain safety margin for reactivity initiated accidents (RIAs), such as a single CEA ejection accident.
Directory of Open Access Journals (Sweden)
Frank Sainsbury
Full Text Available The capacity of plants and plant cells to produce large amounts of recombinant protein has been well established. Due to advantages in terms of speed and yield, attention has recently turned towards the use of transient expression systems, including viral vectors, to produce proteins of pharmaceutical interest in plants. However, the effects of such high level expression from viral vectors and concomitant effects on host cells may affect the quality of the recombinant product.To assess the quality of antibodies transiently expressed to high levels in plants, we have expressed and characterised the human anti-HIV monoclonal antibody, 2G12, using both replicating and non-replicating systems based on deleted versions of Cowpea mosaic virus (CPMV RNA-2. The highest yield (approximately 100 mg/kg wet weight leaf tissue of affinity purified 2G12 was obtained when the non-replicating CPMV-HT system was used and the antibody was retained in the endoplasmic reticulum (ER. Glycan analysis by mass-spectrometry showed that the glycosylation pattern was determined exclusively by whether the antibody was retained in the ER and did not depend on whether a replicating or non-replicating system was used. Characterisation of the binding and neutralisation properties of all the purified 2G12 variants from plants showed that these were generally similar to those of the Chinese hamster ovary (CHO cell-produced 2G12.Overall, the results demonstrate that replicating and non-replicating CPMV-based vectors are able to direct the production of a recombinant IgG similar in activity to the CHO-produced control. Thus, a complex recombinant protein was produced with no apparent effect on its biochemical properties using either high-level expression or viral replication. The speed with which a recombinant pharmaceutical with excellent biochemical characteristics can be produced transiently in plants makes CPMV-based expression vectors an attractive option for
SBWR Model for Steady-State and Transient Analysis
Directory of Open Access Journals (Sweden)
Gilberto Espinosa-Paredes
2008-01-01
Full Text Available This paper presents a model of a simplified boiling water reactor (SBWR to analyze the steady-state and transient behavior. The SBWR model is based on approximations of lumped and distributed parameters to consider neutronics and natural circulation processes. The main components of the model are vessel dome, downcomer, lower plenum, core (channel and fuel, upper plenum, pressure, and level controls. Further consideration of the model is the natural circulation path in the internal circuit of the reactor, which governs the safety performance of the SBWR. To demonstrate the applicability of the model, the predictions were compared with plant data, manufacturer_s predictions, and RELAP5 under steady-state and transient conditions of a typical BWR. In steady-state conditions, the profiles of the main variables of the SBWR core such as superficial velocity, void fraction, temperatures, and convective heat transfer coefficient are presented and analyzed. The transient behavior of SBWR was analyzed during the closure of all main steam line isolation valves (MSIVs. Our results in this transient show that the cooling system due to natural circulation in the SBWR is around 70% of the rated core flow. According to the results shown here, one of the main conclusions of this work is that the simplified model could be very helpful in the licensing process.
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.
Energy Technology Data Exchange (ETDEWEB)
Taylor, C.W.; Mechenbier, J.R.; Matthews, C.E. (Bonneville Power Administration, Portland, OR (United States))
1993-08-01
Transient excitation boosting (TEB) has been installed on the Grand Coulee Third Power Plant hydrogenerators (three 600 MVA units and three 700 MVA units). TEB is initiated for outages of the 3100 MW Pacific HVDC Intertie, and results in a decaying pulse input to the generator voltage regulators. TEB temporarily raises Pacific Northwest transmission voltages which increases voltage-sensitive loads. The increased load brakes Northwest generators which are accelerating because of the loss of HVDC Intertie power. Transient stability of the parallel Pacific AC Intertie is thus improved. Power system-wide commissioning tests were conducted on May 7, 1991. The authors describe the tests and compare test results with simulation results.
Simplified drive system models for power system transient studies in industrial plants
DEFF Research Database (Denmark)
Chen, Peiyuan; Sannino, Ambra
2007-01-01
In order to simulate industrial plants for different power system transient studies, simplified adjustable speed drive (ASD) models are needed. For power system transient studies such as assessing the voltage dip ride-through capability of ASDs, detailed representation of semiconductor valve...... switching can be avoided, thereby making possible to increase the time step of the simulation. In this paper, simplified ASD models are developed and compared with corresponding detailed models. The performance of the simplified models is assessed when increasing the simulation step as much as possible...... while still maintaining the error within acceptable limits....
Transient Ejector Analysis (TEA) code user's guide
Drummond, Colin K.
1993-01-01
A FORTRAN computer program for the semi analytic prediction of unsteady thrust augmenting ejector performance has been developed, based on a theoretical analysis for ejectors. That analysis blends classic self-similar turbulent jet descriptions with control-volume mixing region elements. Division of the ejector into an inlet, diffuser, and mixing region allowed flexibility in the modeling of the physics for each region. In particular, the inlet and diffuser analyses are simplified by a quasi-steady-analysis, justified by the assumption that pressure is the forcing function in those regions. Only the mixing region is assumed to be dominated by viscous effects. The present work provides an overview of the code structure, a description of the required input and output data file formats, and the results for a test case. Since there are limitations to the code for applications outside the bounds of the test case, the user should consider TEA as a research code (not as a production code), designed specifically as an implementation of the proposed ejector theory. Program error flags are discussed, and some diagnostic routines are presented.
Improving transient analysis technology for aircraft structures
Melosh, R. J.; Chargin, Mladen
1989-01-01
Aircraft dynamic analyses are demanding of computer simulation capabilities. The modeling complexities of semi-monocoque construction, irregular geometry, high-performance materials, and high-accuracy analysis are present. At issue are the safety of the passengers and the integrity of the structure for a wide variety of flight-operating and emergency conditions. The technology which supports engineering of aircraft structures using computer simulation is examined. Available computer support is briefly described and improvement of accuracy and efficiency are recommended. Improved accuracy of simulation will lead to a more economical structure. Improved efficiency will result in lowering development time and expense.
Walwyn, David Richard; Huddy, Suzanne M; Rybicki, Edward P
2015-01-01
Despite the advantages of plant-based transient expression systems relative to microbial or mammalian cell systems, the commercial production of recombinant proteins using plants has not yet been achieved to any significant extent. One of the challenges has been the lack of published data on the costs of manufacture for products other than biopharmaceuticals. In this study, we report on the techno-economic analysis of the production of a standard commercial enzyme, namely, horseradish peroxidase (HRP), using a transient expression system in Nicotiana benthamiana. Based on the proven plant yield of 240 mg HRP/kg biomass, a biomass productivity of 15-kg biomass/m(2)/year and a process yield of 54 % (mg HRP product/mg HRP in biomass), it is apparent that HRP can be manufactured economically via transient expression in plants in a large-scale facility (>5 kg HRP/year). At this level, the process is competitive versus the existing technology (extraction of the enzyme from horseradish), and the product is of comparable or improved activity, containing only the preferred isoenzyme C. Production scale, protein yield and biomass productivity are found to be the most important determinants of overall viability.
Transient flow analysis of integrated valve opening process
Energy Technology Data Exchange (ETDEWEB)
Sun, Xinming; Qin, Benke; Bo, Hanliang, E-mail: bohl@tsinghua.edu.cn; Xu, Xingxing
2017-03-15
Highlights: • The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology and the integrated valve (IV) is the key control component. • The transient flow experiment induced by IV is conducted and the test results are analyzed to get its working mechanism. • The theoretical model of IV opening process is established and applied to get the changing rule of the transient flow characteristic parameters. - Abstract: The control rod hydraulic driving system (CRHDS) is a new type of built-in control rod drive technology and the IV is the key control component. The working principle of integrated valve (IV) is analyzed and the IV hydraulic experiment is conducted. There is transient flow phenomenon in the valve opening process. The theoretical model of IV opening process is established by the loop system control equations and boundary conditions. The valve opening boundary condition equation is established based on the IV three dimensional flow field analysis results and the dynamic analysis of the valve core movement. The model calculation results are in good agreement with the experimental results. On this basis, the model is used to analyze the transient flow under high temperature condition. The peak pressure head is consistent with the one under room temperature and the pressure fluctuation period is longer than the one under room temperature. Furthermore, the changing rule of pressure transients with the fluid and loop structure parameters is analyzed. The peak pressure increases with the flow rate and the peak pressure decreases with the increase of the valve opening time. The pressure fluctuation period increases with the loop pipe length and the fluctuation amplitude remains largely unchanged under different equilibrium pressure conditions. The research results lay the base for the vibration reduction analysis of the CRHDS.
Simulation and analysis of a WWER-1000 reactor under normal and transient conditions
Directory of Open Access Journals (Sweden)
Baghban Ghonche
2016-01-01
Full Text Available An accurate analysis of the flow transient is very important in safety evaluation of a nuclear power plant. In this study, analysis of a WWER-1000 reactor is investigated. In order to perform this analysis, a model is developed to simulate the coupled kinetics and thermal-hydraulics of the reactor with a simple and accurate numerical algorithm. For thermal-hydraulic calculations, the four-equation drift-flux model is applied. Based on a multi-channel approach, core is divided into some regions. Each region has different characteristics as represented in a single fuel pin with its associated coolant channel. To obtain the core power distribution, point kinetic equations with different feedback effects are utilized. The appropriate initial and boundary conditions are considered and two situations of decreasing the coolant flow rate in a protected and unprotected core are analyzed. In addition to analysis of normal operation condition, a full range of thermal-hydraulic parameters is obtained for transients too. Finally, the data obtained from the model are compared with the calculations conducted using RELAP5/MOD3 code and Bushehr nuclear power plant data. It is shown that the model can provide accurate predictions for both steady-state and transient conditions.
A hybrid transfinite element approach for nonlinear transient thermal analysis
Tamma, Kumar K.; Railkar, Sudhir B.
1987-01-01
A new computational approach for transient nonlinear thermal analysis of structures is proposed. It is a hybrid approach which combines the modeling versatility of contemporary finite elements in conjunction with transform methods and classical Bubnov-Galerkin schemes. The present study is limited to nonlinearities due to temperature-dependent thermophysical properties. Numerical test cases attest to the basic capabilities and therein validate the transfinite element approach by means of comparisons with conventional finite element schemes and/or available solutions.
Homborg, A.M.; Westing, E.P.M. van; Tinga, T.; Ferrari, G.M.; Zhang, X.; Wit, J.H.W. de; Mol, J.M.C.
2014-01-01
This study validates the ability of Hilbert spectra to investigate transients in an electrochemical noise signal for an aqueous corrosion inhibition process. The proposed analysis procedure involves the identification and analysis of transients in the electrochemical current noise signal. Their
National Research Council Canada - National Science Library
Sainsbury, Frank; Sack, Markus; Stadlmann, Johannes; Quendler, Heribert; Fischer, Rainer; Lomonossoff, George P
2010-01-01
.... To assess the quality of antibodies transiently expressed to high levels in plants, we have expressed and characterised the human anti-HIV monoclonal antibody, 2G12, using both replicating and non...
Benchmarking Of Improved DPAC Transient Deflagration Analysis Code
Energy Technology Data Exchange (ETDEWEB)
Laurinat, James E.; Hensel, Steve J.
2013-03-21
The transient deflagration code DPAC (Deflagration Pressure Analysis Code) has been upgraded for use in modeling hydrogen deflagration transients. The upgraded code is benchmarked using data from vented hydrogen deflagration tests conducted at the HYDRO-SC Test Facility at the University of Pisa. DPAC originally was written to calculate peak deflagration pressures for deflagrations in radioactive waste storage tanks and process facilities at the Savannah River Site. Upgrades include the addition of a laminar flame speed correlation for hydrogen deflagrations and a mechanistic model for turbulent flame propagation, incorporation of inertial effects during venting, and inclusion of the effect of water vapor condensation on vessel walls. In addition, DPAC has been coupled with CEA, a NASA combustion chemistry code. The deflagration tests are modeled as end-to-end deflagrations. The improved DPAC code successfully predicts both the peak pressures during the deflagration tests and the times at which the pressure peaks.
TRANSIENT ANALYSIS OF NONUNIFORM TRANSMISSION LINES WITH NONLINEAR TERMINAL NETWORKS
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A semi-analytical method in time domain is presented for analysis of the transient response of nonuniform transmission lines. In this method, the telegraph equations in time domain is differenced in space domain first, and is transformed into a set of first-order differential equations of voltage and current with respect to time. By integrating these differential equations with respect to time, and precise computation, the solution of these differential equations can be obtained. This method can solve the transient response of various kinds of transmission lines with arbitrary terminal networks. Particularly, it can analyze the nonuniform lines with initial conditions, for which there is no existing effective method to analyze the time response so far. The results obtained with this method are stable and accurate. Two examples are given to illustrate the application of this method.
The pressurization transient analysis for Lungmen advanced boiling water reactor using RETRAN-02
Energy Technology Data Exchange (ETDEWEB)
Tsai, C.-W., E-mail: d937121@oz.nthu.edu.t [Department of Engineering and System Science, National Tsing Hua University, No. 101, Sec. 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China); Shih Chunkuan [Department of Engineering and System Science, National Tsing Hua University, No. 101, Sec. 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, No. 101, Sec. 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China); Wang, J.-R.; Lin, H.-T. [Institute of Nuclear Energy Research, No. 1000, Wenhua Rd., Longtan Township, Taoyuan County 32546, Taiwan (China); Cheng, S.-C. [Department of Nuclear Engineering, Taiwan Power Company, No. 242, Sec. 3, Roosevelt Rd., Taipei City 10016, Taiwan (China)
2010-10-15
A RETRAN-02 model was devised and benchmarked against the preliminary safety analysis report (PSAR) for the Lungmen nuclear power plant roughly 10 years ago. During these years, the fuel design, some of the reactor vessel designs, and control systems have since been revised. The Lungmen RETRAN-02 model has also been modified with updated information when available. This study uses the analytical results of the final safety analysis report (FSAR) to benchmark the Lungmen RETRAN-02 plant model. Five transients, load rejection (LR), turbine trip (TT), main steam line isolation valves closure (MSIVC), loss of feedwater flow (LOFF), and one turbine control valve closure (OTCVC), were utilized to validate the Lungmen RETRAN-02 model. Moreover, due to the strong coupling effect between neutron dynamics and the thermal-hydraulic response during pressurization of transients, the one-dimensional kinetic model with the cross-section data library is used to simulate the coupling effect. The analytical results show good agreement in trends between the RETRAN-02 calculation and the Lungmen FSAR data. Based on the benchmark of these design-basis transients, the modified Lungmen RETRAN-02 model has been adjusted to a level of confidence for analysis of pressure increase transients. Analytical results indicate that the Lungmen advanced boiling water reactor (ABWR) design satisfied design criteria, i.e., vessel pressure and hot shutdown capability. However, a slight difference exists in the simulation of the water level for cases with changes in water levels. The Lungmen RETRAN-02 model tends to predict the change in water level at a slower rate than that in the Lungmen FSAR. There is also a slight difference in void reactivity response toward vessel pressure change in both simulations, which causes the calculated neutron flux before reactor shutdown to differ to some degree when the reactor experiences a rapid pressure increase. Further studies will be performed in the future using
Analysis of transients in advanced heavy water reactor using lumped parameter models
Energy Technology Data Exchange (ETDEWEB)
Manmohan Pandey; Venkata Ramana Eaga; Sankar Sastry, P. [Department of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati (India); Gupta, S.K.; Lele, H.G.; Chatterjee, B. [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai (India)
2005-07-01
Full text of publication follows: Analysis of transients occurring in nuclear power plants, arising from the complex interplay between core neutronics and thermal-hydraulics, is important for their operation and safety. Numerical simulations of such transients can be carried out extensively at very low computational cost by using lumped parameter mathematical models. The Advanced Heavy Water Reactor (AHWR), being developed in India, is a vertical pressure tube type reactor cooled by boiling light water under natural circulation, using thorium as fuel and heavy water as moderator. In the present work, nonlinear and linear lumped parameter dynamic models for AHWR have been developed and validated with a distributed parameter model. The nonlinear lumped model is based on point reactor kinetics equations and one-dimensional homogeneous equilibrium model of two-phase flow. The distributed model is built with RELAP5/MOD3.2 code. Various types of transients have been simulated numerically, using the lumped model as well as RELAP5. The results have been compared and parameters tuned to make the lumped model match the distributed model (RELAP5) in terms of steady state as well as dynamic behaviour. The linear model has been derived by linearizing the nonlinear model for small perturbations about the steady state. Numerical simulations of transients using the linear model have been compared with results obtained from the nonlinear model. Thus, the range of validity of the linear model has been determined. Stability characteristics of AHWR have been investigated using the lumped parameter models. (authors)
NUMERICAL ANALYSIS OF A FEM FOR A TRANSIENT VISCOELASTIC FLOW
Institute of Scientific and Technical Information of China (English)
穆君; 冯民富
2004-01-01
We present the numerical analysis of a coupled method for the numerical simulation of transient viscoelastic flow obeying a differential constitutive equation with a Newtonian viscosity. The scheme used is based on Euler implicit method in time and maintains at each time step a couple of the velocity u and the viscoelastic part of the stress σ. Approximation in space is made by finite element method. The approximate stress, velocity and pressure are, respectively, P1-continuous, p2-continuous, and p1continuous. Upwinding needed for convection of σ is made by a "Streamline Upwind Petrov Galerkin" method (SUPG).
Transient studies of an Integrated Gasification Combined Cycle (IGCC) plant with CO2 capture
Energy Technology Data Exchange (ETDEWEB)
Bhattacharyya, D.; Turton, R.; Zitney, S.
2010-01-01
targets and quality of the feed to other sections, wherever applicable, without violating the operating constraints, and without sacrificing the efficiency. However, it was found that the emission of acid gases may far exceed the environmental targets and the overshoot of some of the key variables may be unacceptable under transient operation while following the load. A number of operational strategies and control configurations is explored for achieving these stringent requirements. The transient response of the plant is also studied by perturbing a number of key inputs.
Transient glyco-engineering to produce recombinant IgA1 with defined N- and O-glycans in plants
Directory of Open Access Journals (Sweden)
Martina eDicker
2016-01-01
Full Text Available The production of therapeutic antibodies to combat pathogens and treat diseases such as cancer is of great interest for the biotechnology industry. The recent development of plant-based expression systems has demonstrated that plants are well-suited for the production of recombinant monoclonal antibodies with defined glycosylation. Compared to immunoglobulin G (IgG, less effort has been undertaken to express immunoglobulin A (IgA, which is the most prevalent antibody class at mucosal sites and a promising candidate for novel recombinant biopharmaceuticals with enhanced anti-tumour activity. Here, we transiently expressed recombinant human IgA1 against the VP8* rotavirus antigen in glyco-engineered deltaXT/FT Nicotiana benthamiana plants. Mass spectrometric analysis of IgA1 glycopeptides revealed the presence of complex biantennary N-glycans with terminal N-acetylglucosamine present on the N-glycosylation site of the CH2 domain in the IgA1 alpha chain. Analysis of the peptide carrying nine potential O-glycosylation sites in the IgA1 alpha chain hinge region showed the presence of plant-specific modifications including hydroxyproline formation and the attachment of pentoses. By co-expression of enzymes required for initiation and elongation of human O-glycosylation it was possible to generate disialylated mucin-type core 1 O-glycans on plant-produced IgA1. Our data demonstrate that deltaXT/FT Nicotiana benthamiana plants can be engineered towards the production of recombinant IgA1 with defined human-type N- and O-linked glycans.
Transient Glyco-Engineering to Produce Recombinant IgA1 with Defined N- and O-Glycans in Plants.
Dicker, Martina; Tschofen, Marc; Maresch, Daniel; König, Julia; Juarez, Paloma; Orzaez, Diego; Altmann, Friedrich; Steinkellner, Herta; Strasser, Richard
2016-01-01
The production of therapeutic antibodies to combat pathogens and treat diseases, such as cancer is of great interest for the biotechnology industry. The recent development of plant-based expression systems has demonstrated that plants are well-suited for the production of recombinant monoclonal antibodies with defined glycosylation. Compared to immunoglobulin G (IgG), less effort has been undertaken to express immunoglobulin A (IgA), which is the most prevalent antibody class at mucosal sites and a promising candidate for novel recombinant biopharmaceuticals with enhanced anti-tumor activity. Here, we transiently expressed recombinant human IgA1 against the VP8* rotavirus antigen in glyco-engineered ΔXT/FT Nicotiana benthamiana plants. Mass spectrometric analysis of IgA1 glycopeptides revealed the presence of complex biantennary N-glycans with terminal N-acetylglucosamine present on the N-glycosylation site of the CH2 domain in the IgA1 alpha chain. Analysis of the peptide carrying nine potential O-glycosylation sites in the IgA1 alpha chain hinge region showed the presence of plant-specific modifications including hydroxyproline formation and the attachment of pentoses. By co-expression of enzymes required for initiation and elongation of human O-glycosylation it was possible to generate disialylated mucin-type core 1 O-glycans on plant-produced IgA1. Our data demonstrate that ΔXT/FT N. benthamiana plants can be engineered toward the production of recombinant IgA1 with defined human-type N- and O-linked glycans.
Probabilistic finite elements for transient analysis in nonlinear continua
Liu, W. K.; Belytschko, T.; Mani, A.
1985-01-01
The probabilistic finite element method (PFEM), which is a combination of finite element methods and second-moment analysis, is formulated for linear and nonlinear continua with inhomogeneous random fields. Analogous to the discretization of the displacement field in finite element methods, the random field is also discretized. The formulation is simplified by transforming the correlated variables to a set of uncorrelated variables through an eigenvalue orthogonalization. Furthermore, it is shown that a reduced set of the uncorrelated variables is sufficient for the second-moment analysis. Based on the linear formulation of the PFEM, the method is then extended to transient analysis in nonlinear continua. The accuracy and efficiency of the method is demonstrated by application to a one-dimensional, elastic/plastic wave propagation problem. The moments calculated compare favorably with those obtained by Monte Carlo simulation. Also, the procedure is amenable to implementation in deterministic FEM based computer programs.
Bucur, D. M.; Dunca, G.; Cervantes, M. J.; Cǎlinoiu, C.; Isbǎşoiu, E. C.
2014-03-01
This paper presents an on-site experimental analysis of a high head hydro power plant and a storage pumping station, in an interconnected complex hydraulic scheme during simultaneous transient operation. The investigated hydropower site has a unique structure as the pumping station discharges the water into the hydropower plant penstock. The operation regimes were chosen for critical scenarios such as sudden load rejections of the turbines as well as start-ups and stops with different combinations of the hydraulic turbines and pumps operation. Several parameters were simultaneously measured such as the pumped water discharge, the pressure at the inlet pump section, at the outlet of the pumps and at the vane house of the hydraulic power plant surge tank. The results showed the dependence of the turbines and the pumps operation. Simultaneous operation of the turbines and the pumps is possible in safe conditions, without endangering the machines or the structures. Furthermore, simultaneous operation of the pumping station together with the hydropower plant increases the overall hydraulic efficiency of the site since shortening the discharge circuit of the pumps.
Development of a system code for transient analysis in a HTGR
Energy Technology Data Exchange (ETDEWEB)
Lee, Tae Beom
2004-02-15
A GAMMA (GAs Multi-component Multi-dimensional Analysis) code is developed for transient analysis and air ingress analysis in High Temperature Gas-cooled Reactors (HTGR). The PBMR of ESKOM is selected as a reference plant for the High Temperature Gas-cooled Reactor here, which uses a direct helium cycle and pebble fuel. Physical models included in GAMMA are the pebble conduction model, radiation heat transfer model, point kinetics model, decay heat model, and component models for break flow, valve, pump, cooler, power conversion unit model. The temperature distribution and the flow distribution of the PBMR are calculated for initial and accident core in the present study. In the accident analysis, typical design basis accident (DBA), including the load transient accident and depressurization accident into the system are selected and analyzed in detail. The predictions by GAMMA for PBMR at 100% power are compared with those by VSOP and PBR{sub S}IM. It turns out that the temperature in the upper region in the third channel predicted by GAMMA is about 62 .deg. C at maximum higher than that by VSOP, but is pretty close to that by PBR{sub S}IM. The center temperature of the fuel shows that that predicted by considering swelling effect is higher than that without swelling effect by about 10 .deg. C. The net efficiency of direct system is higher than that of indirect system due to an effect of the circulator power. The transient capability of GAMMA is validated through analytical solution and PBR{sub S}IM analyzing the depressurization (Loss Of Coolant Accident, LOCA) and load transient accident. After the LOCA the system pressure decreases dramatically from 8MPa to 0.4MPa within 2 sec. After the PI (Proportional-plus-Integral) controller senses that the power shaft is over the set-point of 3,600 rpm, the bypass valve makes shaft speed back to the set-point.
DEFF Research Database (Denmark)
Li, H.; Zhao, B.; Yang, C.
2011-01-01
Increasing levels of wind energy in modern electrical power system is initiating a need for accurate analysis and estimation of transient stability of wind turbine generation systems. This paper investigates the transient behaviors and possible direct methods for transient stability evaluation...... electromagnetic transient models of a SCIG, the transient behaviors of the wind turbine generation system during a three-phase fault are simulated and compared with the traditional models. Secondly, in order to quickly estimate the transient stability limit of the wind turbine generation system, a direct method...... based on normal form theory is proposed. The transient models of the wind turbine generation system including the flexible drive train model are derived based on the direct transient stability estimation method. A method of critical clearing time (CCT) calculation is developed for the transient...
THE PRESSURE TRANSIENT ANALYSIS OF DEFORMATION OF FRACTAL MEDIUM
Institute of Scientific and Technical Information of China (English)
ZHANG Yi-gen; TONG Deng-ke
2008-01-01
The assumption of constant rock properties in pressure-transient analysis of stress-sensitive reservoirs can cause significant errors in the estimation of temporal and spatial variation of pressure. In this article, the pressure transient response of the fractal medium in stress-sensitive reservoirs was studied by using the self-similarity solution method and the regular perturbation method. The dependence of permeability on pore pressure makes the flow equation strongly nonlinear. The nonlinearities associated with the governing equation become weaker by using the logarithm transformation. The perturbation solutions for a constant pressure production and a constant rate production of a linear-source well were obtained by using the self-similarity solution method and the regular perturbation method in an infinitely large system, and inquire into the changing rule of pressure when the fractal and deformation parameters change. The plots of typical pressure curves were given in a few cases, and the results can be applied to well test analysis.
Validation and Application of the Thermal Hydraulic System Code TRACE for Analysis of BWR Transients
Directory of Open Access Journals (Sweden)
V. H. Sánchez
2012-01-01
Full Text Available The Karlsruhe Institute of Technology (KIT is participating on (Code Applications and Maintenance Program CAMP of the US Nuclear Regulatory Commission (NRC to validate TRACE code for LWR transient analysis. The application of TRACE for the safety assessment of BWR requires a throughout verification and validation using experimental data from separate effect and integral tests but also using plant data. The validation process is normally focused on safety-relevant phenomena for example, pressure drop, void fraction, heat transfer, and critical power models. The purpose of this paper is to validate selected BWR-relevant TRACE-models using both data of bundle tests such as the (Boiling Water Reactor Full-Size Fine-Mesh Bundle Test BFBT and plant data recorded during a turbine trip event (TUSA occurred in a Type-72 German BWR plant. For the validation, TRACE models of the BFBT bundle and of the BWR plant were developed. The performed investigations have shown that the TRACE code is appropriate to describe main BWR-safety-relevant phenomena (pressure drop, void fraction, and critical power with acceptable accuracy. The comparison of the predicted global BWR plant parameters for the TUSA event with the measured plant data indicates that the code predictions are following the main trends of the measured parameters such as dome pressure and reactor power.
Transient Analysis of Air-Core Coils by Moment Method
Fujita, Akira; Kato, Shohei; Hirai, Takao; Okabe, Shigemitu
In electric power system a threat of lighting surge is decreased by using ground wire and arrester, but the risk of failure of transformer is still high. Winding is the most familiar conductor configuration of electromagnetic field components such as transformer, resistors, reactance device etc. Therefore, it is important that we invest the lighting surge how to advance into winding, but the electromagnet coupling in a winding makes lighting surge analysis difficult. In this paper we present transient characteristics analysis of an air-core coils by moment method in frequency domain. We calculate the inductance from time response and impedance in low frequency, and compare them with the analytical equation which is based on Nagaoka factor.
Virtual solar field - An opportunity to optimize transient processes in line-focus CSP power plants
Noureldin, Kareem; Hirsch, Tobias; Pitz-Paal, Robert
2017-06-01
Optimizing solar field operation and control is a key factor to improve the competitiveness of line-focus solar thermal power plants. However, the risks of assessing new and innovative control strategies on operational power plants hinder such optimizations and result in applying more conservative control schemes. In this paper, we describe some applications for a whole solar field transient in-house simulation tool developed at the German Aerospace Centre (DLR), the Virtual Solar Field (VSF). The tool offers a virtual platform to simulate real solar fields while coupling the thermal and hydraulic conditions of the field with high computational efficiency. Using the tool, developers and operator can probe their control strategies and assess the potential benefits while avoiding the high risks and costs. In this paper, we study the benefits gained from controlling the loop valves and of using direct normal irradiance maps and forecasts for the field control. Loop valve control is interesting for many solar field operators since it provides a high degree of flexibility to the control of the solar field through regulating the flow rate in each loop. This improves the reaction to transient condition, such as passing clouds and field start-up in the morning. Nevertheless, due to the large number of loops and the sensitivity of the field control to the valve settings, this process needs to be automated and the effect of changing the setting of each valve on the whole field control needs to be taken into account. We used VSF to implement simple control algorithms to control the loop valves and to study the benefits that could be gained from using active loop valve control during transient conditions. Secondly, we study how using short-term highly spatially-resolved DNI forecasts provided by cloud cameras could improve the plant energy yield. Both cases show an improvement in the plant efficiency and outlet temperature stability. This paves the road for further
Energy Technology Data Exchange (ETDEWEB)
Bartlett, E.B.
1995-05-15
The objective of this report is to describe results obtained during the second year of funding that will lead to the development of an artificial neural network (A.N.N) fault diagnostic system for the real-time classification of operational transients at nuclear power plants. The ultimate goal of this three-year project is to design, build, and test a prototype diagnostic adviser for use in the control room or technical support center at Duane Arnold Energy Center (DAEC); such a prototype could be integrated into the plant process computer or safety-parameter display system. The adviser could then warn and inform plant operators and engineers of plant component failures in a timely manner. This report describes the work accomplished in the second of three scheduled years for the project. Included herein is a summary of the second year`s results as well as descriptions of each of the major topics undertaken by the researchers. Also included are reprints of the articles written under this funding as well as those that were published during the funded period.
Significance of Dynamic and Transient Analysis in the Design and Operation of Hybrid Energy Systems
Energy Technology Data Exchange (ETDEWEB)
Panwar, Mayank; Mohanpurkar, Manish; Hovsapian, Rob; Osorio, Julian D.
2015-02-01
Energy systems were historically designed and operated with a specific energy conversion objective, while managing loads and resources. In the recent years, the increased utilization of non-dispatchable renewable sources such as wind and solar has played a role in power quality and the reliability of power systems. In order to mitigate the risk associated with the non-dispatchable resources an integrated approach, such as Hybrid Energy Systems (HES), has to be taken, integrating the loads and resource management between the traditional thermal power plants and the non-dispatchable resources. As our electric energy becomes more diverse in its generation resources, the HES with its operational control system, its real-time view and its dynamic decisions making will become an essential part of the integrated energy systems and improve the overall grid reliability. The operational constraints of the energy sources on both the thermal power plants and the non-dispatchable resources in HES, plays a vital role in the planning and design stage. It is an established fact that the choice of energy source depends on the available natural resources and possible infrastructure. A critical component of decision-making depends on the complementary nature and controllability of the energy sources to supply the load demands with high reliability. Controllability of complex HES to achieve desired performance and flexibility is implemented via coordinated control systems while simultaneously generating electricity and other useful products such as useful heat or hydrogen. These systems are based on instrumentation, signal processing, control theory, and engineering system design. The entire HES along with the control systems are characterized by widely varying time constants. Hence, for a well-coordinated control and operation, we propose physics based modeling of the subsystems to assist in a dynamic and transient analysis. Dynamic and transient analysis in real and non-real time
National Research Council Canada - National Science Library
Ishizuka, Masaru; Hatakeyama, Tomoyuki; Funawatashi, Yuichi; Koizumi, katsuhiro
2011-01-01
.... This paper describes an application of the thermal network method to the transient thermal analysis of multichip modules and proposes a simple model for the thermal analysis of multichip modules as a preliminary thermal design tool. On the basis of the result of transient thermal analysis, the validity of the thermal network method and the simple thermal analysis model is confirmed.
Quantum-corrected transient analysis of plasmonic nanostructures
Uysal, Ismail E.
2017-03-08
A time domain surface integral equation (TD-SIE) solver is developed for quantum-corrected analysis of transient electromagnetic field interactions on plasmonic nanostructures with sub-nanometer gaps. “Quantum correction” introduces an auxiliary tunnel to support the current path that is generated by electrons tunneled between the nanostructures. The permittivity of the auxiliary tunnel and the nanostructures is obtained from density functional theory (DFT) computations. Electromagnetic field interactions on the combined structure (nanostructures plus auxiliary tunnel connecting them) are computed using a TD-SIE solver. Time domain samples of the permittivity and the Green function required by this solver are obtained from their frequency domain samples (generated from DFT computations) using a semi-analytical method. Accuracy and applicability of the resulting quantum-corrected solver scheme are demonstrated via numerical examples.
Transient Reliability Analysis Capability Developed for CARES/Life
Nemeth, Noel N.
2001-01-01
The CARES/Life software developed at the NASA Glenn Research Center provides a general-purpose design tool that predicts the probability of the failure of a ceramic component as a function of its time in service. This award-winning software has been widely used by U.S. industry to establish the reliability and life of a brittle material (e.g., ceramic, intermetallic, and graphite) structures in a wide variety of 21st century applications.Present capabilities of the NASA CARES/Life code include probabilistic life prediction of ceramic components subjected to fast fracture, slow crack growth (stress corrosion), and cyclic fatigue failure modes. Currently, this code can compute the time-dependent reliability of ceramic structures subjected to simple time-dependent loading. For example, in slow crack growth failure conditions CARES/Life can handle sustained and linearly increasing time-dependent loads, whereas in cyclic fatigue applications various types of repetitive constant-amplitude loads can be accounted for. However, in real applications applied loads are rarely that simple but vary with time in more complex ways such as engine startup, shutdown, and dynamic and vibrational loads. In addition, when a given component is subjected to transient environmental and or thermal conditions, the material properties also vary with time. A methodology has now been developed to allow the CARES/Life computer code to perform reliability analysis of ceramic components undergoing transient thermal and mechanical loading. This means that CARES/Life will be able to analyze finite element models of ceramic components that simulate dynamic engine operating conditions. The methodology developed is generalized to account for material property variation (on strength distribution and fatigue) as a function of temperature. This allows CARES/Life to analyze components undergoing rapid temperature change in other words, components undergoing thermal shock. In addition, the capability has
Thermal Power Plant Performance Analysis
2012-01-01
The analysis of the reliability and availability of power plants is frequently based on simple indexes that do not take into account the criticality of some failures used for availability analysis. This criticality should be evaluated based on concepts of reliability which consider the effect of a component failure on the performance of the entire plant. System reliability analysis tools provide a root-cause analysis leading to the improvement of the plant maintenance plan. Taking in view that the power plant performance can be evaluated not only based on thermodynamic related indexes, such as heat-rate, Thermal Power Plant Performance Analysis focuses on the presentation of reliability-based tools used to define performance of complex systems and introduces the basic concepts of reliability, maintainability and risk analysis aiming at their application as tools for power plant performance improvement, including: · selection of critical equipment and components, · defini...
Transient responses of phosphoric acid fuel cell power plant system. Ph.D. Thesis
Lu, Cheng-Yi
1983-01-01
An analytical and computerized study of the steady state and transient response of a phosphoric acid fuel cell (PAFC) system was completed. Parametric studies and sensitivity analyses of the PAFC system's operation were accomplished. Four non-linear dynamic models of the fuel cell stack, reformer, shift converters, and heat exchangers were developed based on nonhomogeneous non-linear partial differential equations, which include the material, component, energy balance, and electrochemical kinetic features. Due to a lack of experimental data for the dynamic response of the components only the steady state results were compared with data from other sources, indicating reasonably good agreement. A steady state simulation of the entire system was developed using, nonlinear ordinary differential equations. The finite difference method and trial-and-error procedures were used to obtain a solution. Using the model, a PAFC system, that was developed under NASA Grant, NCC3-17, was improved through the optimization of the heat exchanger network. Three types of cooling configurations for cell plates were evaluated to obtain the best current density and temperature distributions. The steady state solutions were used as the initial conditions in the dynamic model. The transient response of a simplified PAFC system, which included all of the major components, subjected to a load change was obtained. Due to the length of the computation time for the transient response calculations, analysis on a real-time computer was not possible. A simulation of the real-time calculations was developed on a batch type computer. The transient response characteristics are needed for the optimization of the design and control of the whole PAFC system. All of the models, procedures and simulations were programmed in Fortran and run on IBM 370 computers at Cleveland State University and the NASA Lewis Research Center.
Circelli, Patrizia; Donini, Marcello; Villani, Maria Elena; Benvenuto, Eugenio
2010-01-01
We have recently described an efficient transient expression system mediated by Agrobacterium tumefaciens for the production of HIV-1 Nef protein in Nicotiana benthamiana plants. In order to enhance the yield of recombinant protein we assayed the effect of three gene-silencing viral suppressor proteins (P25 of Potato Virus X, P19 of Artichoke Mottled Crinckle virus and Tomato Bushy Stunt virus) on Nef expression levels. Results demonstrated that AMCV-P19 gave the highest Nef yield (1.3% of total soluble protein) and that this effect was correlated to a remarkable decrease of Nef-specific small interfering RNAs (siRNAs) indicating an effective modulation of RNA silencing mechanisms. Here we report additional data on the production of different heterologous proteins including human immunoglobulin heavy and light chains and a virus coat protein that demonstrate the robustness of this co-agroinfiltration expression system boosted by the AMCV-P19 gene-silencing suppressor. PMID:21326930
Directory of Open Access Journals (Sweden)
Sunday J. IBRAHIM
2013-06-01
Full Text Available Safety and transient analyses of a pressurised water reactor (PWR using the Personal Computer Transient Analyzer (PCTRAN simulator was carried out. The analyses presented a synergistic integration of a numerical model; a full scope high fidelity simulation system which adopted point reactor neutron kinetics model and movable boundary two phase fluid models to simplify the calculation of the program, so it could achieve real-time simulation on a personal computer. Various scenarios of transients and accidents likely to occur at any nuclear power plant were simulated. The simulations investigated the change of signals and parameters vis a vis loss of coolant accident, scram, turbine trip, inadvertent control rod insertion and withdrawal, containment failure, fuel handling accident in auxiliary building and containment, moderator dilution as well as a combination of these parameters. Furthermore, statistical analyses of the PCTRAN results were carried out. PCTRAN results for the loss of coolant accident (LOCA caused a rapid drop in coolant pressure at the rate of 21.8KN/m2/sec triggering a shutdown of the reactor protection system (RPS, while the turbine trip accident showed a rapid drop in total plant power at the rate of 14.3 MWe/sec causing a downtime in the plant. Fuel handling accidents mimic results showed release of radioactive materials in unacceptable doses. This work shows the potential classes of nuclear accidents likely to occur during operation in proposed reactor sites. The simulations are very appropriate in the light of Nigeria’s plan to generate nuclear energy in the region of 1000 MWe from reactors by 2017.
Energy Technology Data Exchange (ETDEWEB)
Chien, T.H.; Domanus, H.M.; Sha, W.T.
1993-02-01
The COMMIX-PPC computer pregrain is an extended and improved version of earlier COMMIX codes and is specifically designed for evaluating the thermal performance of power plant condensers. The COMMIX codes are general-purpose computer programs for the analysis of fluid flow and heat transfer in complex Industrial systems. In COMMIX-PPC, two major features have been added to previously published COMMIX codes. One feature is the incorporation of one-dimensional equations of conservation of mass, momentum, and energy on the tube stile and the proper accounting for the thermal interaction between shell and tube side through the porous-medium approach. The other added feature is the extension of the three-dimensional conservation equations for shell-side flow to treat the flow of a multicomponent medium. COMMIX-PPC is designed to perform steady-state and transient. Three-dimensional analysis of fluid flow with heat transfer tn a power plant condenser. However, the code is designed in a generalized fashion so that, with some modification, it can be used to analyze processes in any heat exchanger or other single-phase engineering applications. Volume I (Equations and Numerics) of this report describes in detail the basic equations, formulation, solution procedures, and models for a phenomena. Volume II (User's Guide and Manual) contains the input instruction, flow charts, sample problems, and descriptions of available options and boundary conditions.
Energy Technology Data Exchange (ETDEWEB)
Chien, T.H.; Domanus, H.M.; Sha, W.T.
1993-02-01
The COMMIX-PPC computer program is an extended and improved version of earlier COMMIX codes and is specifically designed for evaluating the thermal performance of power plant condensers. The COMMIX codes are general-purpose computer programs for the analysis of fluid flow and heat transfer in complex industrial systems. In COMMIX-PPC, two major features have been added to previously published COMMIX codes. One feature is the incorporation of one-dimensional conservation of mass. momentum, and energy equations on the tube side, and the proper accounting for the thermal interaction between shell and tube side through the porous medium approach. The other added feature is the extension of the three-dimensional conservation equations for shell-side flow to treat the flow of a multicomponent medium. COMMIX-PPC is designed to perform steady-state and transient three-dimensional analysis of fluid flow with heat transfer in a power plant condenser. However, the code is designed in a generalized fashion so that, with some modification. it can be used to analyze processes in any heat exchanger or other single-phase engineering applications.
Perturbation analysis of transient population dynamics using matrix projection models
DEFF Research Database (Denmark)
Stott, Iain
2016-01-01
Non-stable populations exhibit short-term transient dynamics: size, growth and structure that are unlike predicted long-term asymptotic stable, stationary or equilibrium dynamics. Understanding transient dynamics of non-stable populations is important for designing effective population management...... strategies, predicting the responses of populations to environmental change or disturbance, and understanding population processes and life-history evolution in variable environments. Transient perturbation analyses are vital tools for achieving these aims. They assess how transient dynamics are affected...... of model being analysed, the perturbation structure, the population response of interest, nonlinear response to perturbation, standardization for asymptotic dynamics, the initial population structure, and the time frame of interest. I discuss these with reference to the application of transient...
Unsupervised Transient Light Curve Analysis Via Hierarchical Bayesian Inference
Sanders, Nathan; Soderberg, Alicia
2014-01-01
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 photometr...
An Effective Distributed Model for Power System Transient Stability Analysis
Directory of Open Access Journals (Sweden)
MUTHU, B. M.
2011-08-01
Full Text Available The modern power systems consist of many interconnected synchronous generators having different inertia constants, connected with large transmission network and ever increasing demand for power exchange. The size of the power system grows exponentially due to increase in power demand. The data required for various power system applications have been stored in different formats in a heterogeneous environment. The power system applications themselves have been developed and deployed in different platforms and language paradigms. Interoperability between power system applications becomes a major issue because of the heterogeneous nature. The main aim of the paper is to develop a generalized distributed model for carrying out power system stability analysis. The more flexible and loosely coupled JAX-RPC model has been developed for representing transient stability analysis in large interconnected power systems. The proposed model includes Pre-Fault, During-Fault, Post-Fault and Swing Curve services which are accessible to the remote power system clients when the system is subjected to large disturbances. A generalized XML based model for data representation has also been proposed for exchanging data in order to enhance the interoperability between legacy power system applications. The performance measure, Round Trip Time (RTT is estimated for different power systems using the proposed JAX-RPC model and compared with the results obtained using traditional client-server and Java RMI models.
The Transient Modal Dynamic Analysis of a Coke Tower
Institute of Scientific and Technical Information of China (English)
XIE Teng-teng; SUN Tie; XING Ling; ZHANG Su-xiang
2012-01-01
Dynamic analysis must be performed when the duration of the applied load is short or if the load is dynamic in nature. Wind load, as a random load, can lead to the vibration of the coke tower. In order to study the influence to the strength of the coke tower by wind, ABAQUS was used to conduct the transient modal dynamic analysis of the wind load. The response of the structure during loading and unloading was mainly observed. The results indicate that, with the effect of wind, the maximal nodal displacement appears at the top of the tower, which is 0.79 mm; while the maximal stress locates at the node around the skirt, the maximum is 3.26 MPa. Both of the displacement and stress cannot cause the failure of the structure. After loading and unloading, the structure engenders vibration along the loading direction. The frequency is 10 Hz, under the effect of external loads, it may easily cause the resonance of the structure, which can cause damage to the structure. So it must be taken into consideration during the process of design and operation.
Rotordynamics on the PC: Transient Analysis With ARDS
Fleming, David P.
1997-01-01
Personal computers can now do many jobs that formerly required a large mainframe computer. An example is NASA Lewis Research Center's program Analysis of RotorDynamic Systems (ARDS), which uses the component mode synthesis method to analyze the dynamic motion of up to five rotating shafts. As originally written in the early 1980's, this program was considered large for the mainframe computers of the time. ARDS, which was written in Fortran 77, has been successfully ported to a 486 personal computer. Plots appear on the computer monitor via calls programmed for the original CALCOMP plotter; plots can also be output on a standard laser printer. The executable code, which uses the full array sizes of the mainframe version, easily fits on a high-density floppy disk. The program runs under DOS with an extended memory manager. In addition to transient analysis of blade loss, step turns, and base acceleration, with simulation of squeeze-film dampers and rubs, ARDS calculates natural frequencies and unbalance response.
Deterministic and Probabilistic Analysis against Anticipated Transient Without Scram
Energy Technology Data Exchange (ETDEWEB)
Choi, Sun Mi; Kim, Ji Hwan [KHNP Central Research Institute, Daejeon (Korea, Republic of); Seok, Ho [KEPCO Engineering and Construction, Daejeon (Korea, Republic of)
2016-10-15
An Anticipated Transient Without Scram (ATWS) is an Anticipated Operational Occurrences (AOOs) accompanied by a failure of the reactor trip when required. By a suitable combination of inherent characteristics and diverse systems, the reactor design needs to reduce the probability of the ATWS and to limit any Core Damage and prevent loss of integrity of the reactor coolant pressure boundary if it happens. This study focuses on the deterministic analysis for the ATWS events with respect to Reactor Coolant System (RCS) over-pressure and fuel integrity for the EU-APR. Additionally, this report presents the Probabilistic Safety Assessment (PSA) reflecting those diverse systems. The analysis performed for the ATWS event indicates that the NSSS could be reached to controlled and safe state due to the addition of boron into the core via the EBS pump flow upon the EBAS by DPS. Decay heat is removed through MSADVs and the auxiliary feedwater. During the ATWS event, RCS pressure boundary is maintained by the operation of primary and secondary safety valves. Consequently, the acceptance criteria were satisfied by installing DPS and EBS in addition to the inherent safety characteristics.
Homborg, A.M.; Westing, E.P.M. van; Tinga, T.; Ferrari, G.M.; Zhang, X.; Wit, J.H.W. de; Mol, J.M.C.
2014-01-01
This study validates the ability of Hilbert spectra to investigate transients in an electrochemical noise signal for an aqueous corrosion inhibition process. The proposed analysis procedure involves the identification and analysis of transients in the electrochemical current noise signal. Their deco
Homborg, A.M.; Westing, van E.P.M.; Tinga, T.; Ferrari, G.M.; Zhang, X.; Wit, de J.H.W.; Mol, J.M.C.
2013-01-01
This study validates the ability of Hilbert spectra to investigate transients in an electrochemical noise signal for an aqueous corrosion inhibition process. The proposed analysis procedure involves the identification and analysis of transients in the electrochemical current noise signal. Their deco
The Dynamic Monte Carlo Method for Transient Analysis of Nuclear Reactors
Sjenitzer, B.L.
2013-01-01
In this thesis a new method for the analysis of power transients in a nuclear reactor is developed, which is more accurate than the present state-of-the-art methods. Transient analysis is important tool when designing nuclear reactors, since they predict the behaviour of a reactor during changing co
On the feasibility of a transient dynamic design analysis method
Ohara, George J.; Cunniff, Patrick F.
1992-04-01
This Annual Report summarizes the progress that was made during the first year of the two-year grant from the Office of Naval Research. The dynamic behavior of structures subjected to mechanical shock loading provides a continuing problem for design engineers concerned with shipboard foundations supporting critical equipment. There are two particular problems associated with shock response that are currently under investigation. The first topic explores the possibilities of developing a transient design analysis method that does not degrade the current level of the Navy's shock-proofness requirements for heavy shipboard equipment. The second topic examines the prospects of developing scaling rules for the shock response of simple internal equipment of submarines subjected to various attack situations. This effort has been divided into two tasks: chemical explosive scaling for a given hull; and scaling of equipment response across different hull sizes. The computer is used as a surrogate shock machine for these studies. Hence, the results of the research can provide trends, ideas, suggestions, and scaling rules to the Navy. In using these results, the shock-hardening program should use measured data rather than calculated data.
Energy Technology Data Exchange (ETDEWEB)
Magalhaes, Mardson Alencar de Sa; Lira, Carlos Alberto Brayner de Oliveira; Silva, Mario Augusto Bezerra da, E-mail: cabol@ufpe.b [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear; Lima, Fernando Roberto de Andrade, E-mail: falima@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN-NE/CNEN-PE), Recife, PE (Brazil)
2011-07-01
The IRIS project has significantly advanced in the last few years in response to a demand for a new generation reactor, that could fulfill the essential requirements for a future nuclear power plant: better economics, safety-by-design, low proliferation risk and environmental sustainability. IRIS reactor is a integral type PWR in which all primary components are arranged inside the pressure vessel. This configuration involves important changes in relation to a conventional PWR. These changes require several studies to comply with the safe operational limits for the reactor. In this paper, a study has been conducted to develop a dynamic model (named MODIRIS) for transient analysis, implemented in the MATLAB'S software SIMULINK, allowing the analysis of IRIS behavior by considering the neutron point kinetics for power production. The methodology is based on generating a set of differential equations of neutronic and thermal-hydraulic balances which describes the dynamics of the primary circuit, as well as a set of differential equations describing the dynamics of secondary circuit. The equations and initialization parameters at full power were into the SIMULINK and the code was validated by the confrontation with RELAP simulations for a transient of feedwater reduction in the steam generators. (author)
Directory of Open Access Journals (Sweden)
Naomichi eFujiuchi
2016-03-01
Full Text Available Agrobacterium-mediated transient expression systems enable plants to produce a wide range of recombinant proteins on a rapid timescale. To achieve economically feasible upstream production and downstream processing, two yield parameters should be considered: 1 recombinant protein content per unit biomass; and 2 recombinant protein productivity per unit area-time at the end of the upstream production. Because environmental factors in the upstream production have impacts on those parameters, environment control is important to maximize the recombinant protein yield. In this review, we summarize the effects of pre- and post-inoculation environmental factors in the upstream production on the yield parameters and discuss the basic concept of environment control for plant-based transient expression systems. Pre-inoculation environmental factors associated with planting density, light quality and nutrient supply affect plant characteristics such as biomass and morphology, which in turn affect recombinant protein content and productivity. Accordingly, environment control for such plant characteristics has significant implications to achieve a high yield. On the other hand, post-inoculation environmental factors such as temperature, light intensity and humidity have been shown to affect recombinant protein content. Considering that recombinant protein production in Agrobacterium-mediated transient expression systems is a result of a series of complex biological events starting from T-DNA transfer from Agrobacterium tumefaciens to protein biosynthesis and accumulation in leaf tissue, we propose that dynamic environment control during the post-inoculation process, i.e., changing environmental conditions at an appropriate timing for each event, may be a promising approach to obtain a high yield. Detailed descriptions of plant growth conditions and careful examination of environmental effects will significantly contribute to our knowledge to stably obtain
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...
Analysis of a transcription factor using transient assay in Arabidopsis protoplasts.
Iwata, Yuji; Lee, Mi-Hyun; Koizumi, Nozomu
2011-01-01
Regulation of gene expression by transcription factors is a fundamental mechanism in essentially all aspects of cellular processes. Transient expression assay of a reporter plasmid containing a reporter gene driven by a promoter of interest and an effector plasmid expressing a transcription factor has been a powerful tool for analyzing transcription factors. Here we present a protocol for polyethylene glycol (PEG)-mediated transformation of Arabidopsis protoplasts. It details preparation of protoplasts from Arabidopsis suspension cultured cells or leaves of soil-grown Arabidopsis plants and subsequent PEG-mediated transformation with reporter and effector plasmids. This protocol can be completed within 24 h from protoplast preparation to reporter assay. As an example, analysis of the membrane-bound transcription factor AtbZIP60 and its target BiP3 promoter is shown.
TREAT Transient Analysis Benchmarking for the HEU Core
Energy Technology Data Exchange (ETDEWEB)
Kontogeorgakos, D. C. [Argonne National Lab. (ANL), Argonne, IL (United States); Connaway, H. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Wright, A. E. [Argonne National Lab. (ANL), Argonne, IL (United States)
2014-05-01
This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high enriched uranium (HEU) fuel to the use of low enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to benchmark the transient calculations against temperature-limited transients performed in the final operating HEU TREAT core configuration. The MCNP code was used to evaluate steady-state neutronics behavior, and the point kinetics code TREKIN was used to determine core power and energy during transients. The first part of the benchmarking process was to calculate with MCNP all the neutronic parameters required by TREKIN to simulate the transients: the transient rod-bank worth, the prompt neutron generation lifetime, the temperature reactivity feedback as a function of total core energy, and the core-average temperature and peak temperature as a functions of total core energy. The results of these calculations were compared against measurements or against reported values as documented in the available TREAT reports. The heating of the fuel was simulated as an adiabatic process. The reported values were extracted from ANL reports, intra-laboratory memos and experiment logsheets and in some cases it was not clear if the values were based on measurements, on calculations or a combination of both. Therefore, it was decided to use the term “reported” values when referring to such data. The methods and results from the HEU core transient analyses will be used for the potential LEU core configurations to predict the converted (LEU) core’s performance.
Energy Technology Data Exchange (ETDEWEB)
Antonopoulos-Domis, M.; Tambouratzis, T. [NCSR, Athens (Greece). Institute of Nuclear Technology-Radiation Protection
1997-12-22
A method is proposed for system identification during a transient, employing wavelet multiresolution analysis and denoising followed by classical (FFT) special analysis. The method has been tested on numerical experiments. (Author).
Energy Technology Data Exchange (ETDEWEB)
Antonopoulos-Domis, M.; Tambouratzis, T
1998-05-01
A method is proposed for system identification during a transient, employing wavelet multiresolution analysis and denoising followed by classical (FFT) special analysis. The method has been tested on numerical experiments.
Theoretical analysis of transient heat conduction in sand
Institute of Scientific and Technical Information of China (English)
梁新刚; 过增元; 徐云生
1996-01-01
A simplified two-phase system model, with the heat transfer between phases considered, is presented and applied to the transient heat conduction in sand. The analytical results show that the one-dimensional Fourier’s law is not applicable to the transient heat conduction at very short time and there is no thermal wave described by C-V equation in sand. The two-phase system model correlates with experimental data well. Each ?phase responds to heating at different speeds in composite material, and consequently results in a temperature difference between phases. This difference will cause heat transfer between phases, which can be regarded as a heat source or sink to other phase. It is certain that Fourier’s law cannot describe the transient heat conduction in sand if a one-dimensional problem with equivalent thermal diffusivity is assumed.
An Analysis of a Rural Pennsylvania School District's Transient Population and NCLB Scores
Lesisko, Lee J.; Wright, Robert J.
2009-01-01
Pennsylvania System of School Assessment (PSSA) data from one rural school system covering four groups of children for a consecutive three year period was used to study the impact of transient students entering the school system. The analysis compared native children (those on roll since the first year) with transient children added to or deleted…
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.
Analysis of interference in attosecond transient absorption in adiabatic condition
Dong, Wenpu; Wang, Xiaowei; Zhao, Zengxiu
2015-01-01
We simulate the transient absorption of attosecond pulses of infrared laser-dressed atoms by considering a three-level system with the adiabatic approximation. We study the delay-dependent interference features in the transient absorption spectra of helium atoms from the perspective of the coherent interaction processes between the attosecond pulse and the quasi-harmonics, and find that many features of the interference fringes in the absorption spectra of the attosecond pulse can be attributed to the coherence phase difference. And the modulation signals of laser-induced sidebands of the dark state is found related to the dark state with population modulated by the dressing field.
ANALYSIS OF TRANSIENT THERMAL STRESS IN CYLINDRICALLY ORTHOTROPIC TUBES
Institute of Scientific and Technical Information of China (English)
凌道盛
2003-01-01
The incorrect deduction of equations in the research works devoted to the studies of transient stress in cylindrically orthotropic tubes and done by Kardomateas ( Journal of Applied Mechanics, 1989, 1990) leads to the wrong results. The errata (1991) correct the deduction error, but do not give the right numerical results. All errors are corrected, and the Mathematica is adopted to solve the large argument problem for Bessel function. A theoretical solution of the transient thermal stresses in tubes with uniform form is presented,and a numerical example is studied.
Analysis of power transients in a cascade of EDFAs
Institute of Scientific and Technical Information of China (English)
ZhangyuanChen; GuishengXiong; 等
1997-01-01
Power transients in a cascade of EDFAs are investigated by numerical simulations.The rate of transient response induced by the channel number variation is found to scale with the number of EDFAs and overshoots and relax oscilations are observed after several EDFAs.The slope of 1-dB power change time scales linearly with the number of EDFAs.The influence of pump variation on the output is large for a single EDFA,but small after many EDFAs.The response of power control must be fast enough to limit the power excursion.
Chirospecific analysis of plant volatiles
Energy Technology Data Exchange (ETDEWEB)
Tkachev, A V [N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk (Russian Federation)
2007-10-31
Characteristic features of the analysis of plant volatiles by enantioselective gas (gas-liquid) chromatography and gas chromatography/mass spectrometry are discussed. The most recent advances in the design of enantioselective stationary phases are surveyed. Examples of the preparation of the most efficient phases based on modified cyclodextrins are given. Current knowledge on the successful analytical resolution of different types of plant volatiles (aliphatic and aromatic compounds and mono-, sesqui- and diterpene derivatives) into optical antipodes is systematically described. Chiral stationary phases used for these purposes, temperature conditions and enantiomer separation factors are summarised. Examples of the enantiomeric resolution of fragrance compounds and components of plant extracts, wines and essential oils are given.
Chirospecific analysis of plant volatiles
Tkachev, A. V.
2007-10-01
Characteristic features of the analysis of plant volatiles by enantioselective gas (gas-liquid) chromatography and gas chromatography/mass spectrometry are discussed. The most recent advances in the design of enantioselective stationary phases are surveyed. Examples of the preparation of the most efficient phases based on modified cyclodextrins are given. Current knowledge on the successful analytical resolution of different types of plant volatiles (aliphatic and aromatic compounds and mono-, sesqui- and diterpene derivatives) into optical antipodes is systematically described. Chiral stationary phases used for these purposes, temperature conditions and enantiomer separation factors are summarised. Examples of the enantiomeric resolution of fragrance compounds and components of plant extracts, wines and essential oils are given.
Identification of a cis-regulatory element by transient analysis of co-ordinately regulated genes
Directory of Open Access Journals (Sweden)
Allan Andrew C
2008-07-01
Full Text Available Abstract Background Transcription factors (TFs co-ordinately regulate target genes that are dispersed throughout the genome. This co-ordinate regulation is achieved, in part, through the interaction of transcription factors with conserved cis-regulatory motifs that are in close proximity to the target genes. While much is known about the families of transcription factors that regulate gene expression in plants, there are few well characterised cis-regulatory motifs. In Arabidopsis, over-expression of the MYB transcription factor PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT 1 leads to transgenic plants with elevated anthocyanin levels due to the co-ordinated up-regulation of genes in the anthocyanin biosynthetic pathway. In addition to the anthocyanin biosynthetic genes, there are a number of un-associated genes that also change in expression level. This may be a direct or indirect consequence of the over-expression of PAP1. Results Oligo array analysis of PAP1 over-expression Arabidopsis plants identified genes co-ordinately up-regulated in response to the elevated expression of this transcription factor. Transient assays on the promoter regions of 33 of these up-regulated genes identified eight promoter fragments that were transactivated by PAP1. Bioinformatic analysis on these promoters revealed a common cis-regulatory motif that we showed is required for PAP1 dependent transactivation. Conclusion Co-ordinated gene regulation by individual transcription factors is a complex collection of both direct and indirect effects. Transient transactivation assays provide a rapid method to identify direct target genes from indirect target genes. Bioinformatic analysis of the promoters of these direct target genes is able to locate motifs that are common to this sub-set of promoters, which is impossible to identify with the larger set of direct and indirect target genes. While this type of analysis does not prove a direct interaction between protein and DNA
Numerical analysis of power system transients and dynamics
Ametani, Akihiro
2015-01-01
This book describes the three major power system transient and dynamics simulation tools based on a circuit-theory based approach which are most widely used all over the world (EMTP-ATP, EMTP-RV and EMTDC/PSCAD), together with other powerful simulation tools such as XTAP.
Clinical analysis on neuroprotection of transient ischemic attacks
Institute of Scientific and Technical Information of China (English)
Dimitar Maslarov; Desislava Drenska
2011-01-01
Transient ischemic attack (TIA) is an acute cerebrovascular incident, and is generally considered the best opportunity for early neuroprotective treatment against cerebral ischemia. This study retrospectively analyzed 80 patients with TIA (38 males and 42 females). Among 61 patients who received neuroprotective cerebrolysin treatment within 24 hours after TIA onset, 13 (21.31%)patients suffered subsequent strokes. Among 19 patients who received neuroprotective
Compositional Abstraction of PEPA Models for Transient Analysis
DEFF Research Database (Denmark)
Smith, Michael James Andrew
2010-01-01
- or interval - Markov chains allow us to aggregate states in such a way as to safely bound transient probabilities of the original Markov chain. Whilst we can apply this technique directly to a PEPA model, it requires us to obtain the CTMC of the model, whose state space may be too large to construct...
Vibrational Analysis of (SCN)2 and the Transient (SCN)2
DEFF Research Database (Denmark)
Jensen, N. H.; Wilbrandt, Robert Walter; Pagsberg, Palle Bjørn
1979-01-01
The vibrational spectra of thiocyanogen and the transient radical anion (SCN)2− are interpreted in detail through molecular orbital and normal coordinate calculations. The results support the assignment of (SCN)2− to the anion of thiocyanogen and indicate a substantial weakening of the S–S and C...
ANALYSIS OF THE TRANSIENT STABILITY LIMIT OF NIGERIA'S ...
African Journals Online (AJOL)
user
Keywords: Disturbance, Transient stability, Grid Fragility, Network, Nigerian ... http://dx.doi.org/10.4314/njt.v36i1.26 ..... using generalized regression neural networks” Int. J. Applied .... of the extreme learning machine method; Int. J, Electrical.
Effect analysis of transient scenarios for successful water management strategies
Haasnoot, M.; Middelkoop, H.; Deursen, van W.; Beek, van E.; Beersma, J.; Erdbrink, C.D.; Os, van A.G.
2008-01-01
Recent scenario studies on water management focus on one or two projection years and the effects on the water system and functions. The future is however more complex and dynamic. Therefore, we analyse transient scenarios in order to evaluate the performance of water management strategies. Current a
Transient Stability Performance Analysis of Power System Using Facts Devices
Directory of Open Access Journals (Sweden)
M. Srinivasa Rao
2014-02-01
Full Text Available Transient stability is increasingly important for secure loading. Transient stability evaluation of large scale power systems is an extremely intricate and highly non linear problem. An important function of transient evaluation is to appraise the capability of the power system to with stand serious contingency in time, so that some emergencies or preventive control can be carried out to prevent system breakdown, the fault current so produced is diverted to the capacitor by using dual-STATCOM controller, results proved that voltage is maintained nearly constant, surge currents decreased and oscillations in generator have damped and hence system stability and continuity of supply are enhanced. If for UPFC, replacing series controller with shunt controller, it works as dual STATCOM. It has advantages as series pulse controller is not required and same pulses can be given to both STATCOMs. The shunt controller is so designed to act as low impedance path for short circuit current, thereby surge currents can be diverted to VSC. A general program for transient stability studies to incorporate FACTS devices is developed using MATLAB/SIMULINK.
Energy Technology Data Exchange (ETDEWEB)
Li, H.; Yang, C.; Chen, H.W. [The State Key Laboratory of Equipment and System Safety of Power Transmission and Distribution and New Technology, Electrical Engineering College of Chongqing University, Chongqing 400044 (China); Zhao, B. [The State Key Laboratory of Equipment and System Safety of Power Transmission and Distribution and New Technology, Electrical Engineering College of Chongqing University, Chongqing 400044 (China); Sichuan Electric Vocational and Technical College, Chengdu 610072 (China); Chen, Z. [Institute of Energy Technology, Aalborg University, Aalborg East DK-9220 (Denmark)
2011-05-15
Increasing levels of wind energy in modern electrical power system is initiating a need for accurate analysis and estimation of transient stability of wind turbine generation systems. This paper investigates the transient behaviors and possible direct methods for transient stability evaluation of a grid-connected wind turbine with squirrel cage induction generator (SCIG). Firstly, by using an equivalent lump mass method, a three-mass wind turbine equivalent model is proposed considering both the blades and the shaft flexibility of the wind turbine drive train system. Combined with the detailed electromagnetic transient models of a SCIG, the transient behaviors of the wind turbine generation system during a three-phase fault are simulated and compared with the traditional models. Secondly, in order to quickly estimate the transient stability limit of the wind turbine generation system, a direct method based on normal form theory is proposed. The transient models of the wind turbine generation system including the flexible drive train model are derived based on the direct transient stability estimation method. A method of critical clearing time (CCT) calculation is developed for the transient stability estimation of the wind turbine generation system. Finally, the CCT at various initial mechanical torques for different dynamical models are calculated and compared with the trial and error method by simulation, when the SCIG stator terminal is subjected to a three-phase short-circuit fault. The results have shown the proposed method and models are correct and valid. (author)
Transient Analysis of Steam Generator in PWR Nuclear Power Plant
Institute of Scientific and Technical Information of China (English)
1998-01-01
ＮｏｍｅｎｃｌａｔｕｒｅＡＡｒｅａ（ｍ２）ＤｈＨｙｄｒａｕｌｉｃＤｉａｍｅｔｅｒ（ｍ）ＥＥｎｅｒｇｙＣｏｎｔｅｎｔ（Ｊ）ｆＰｒｅｓｓｕｒｅＬｏｓｓＣｏｅｆｉｃｉｅｎｔαＶｏｉｄＦｒａｃｔｉｏｎＨＳｐｅｃｉｆｉｃＥｎｔｈａｌｐｙ（Ｊ／ｋｇ）ＩＩｎｅｒｔ...
2013-01-01
In this work the transient simulations of four hybrid solar tower power plant concepts with open-volumetric receiver technology for a location in Barstow-Daggett, USA, are presented. The open-volumetric receiver uses ambient air as heat transfer fluid and the hybridization is realized with a gas turbine. The Rankine cycle is heated by solar-heated air and/or by the gas turbine’s flue gases. The plant can be operated in solar-only, hybrid parallel or combined cycle-only mode as well a...
Dynamic remedial action scheme using online transient stability analysis
Shrestha, Arun
Economic pressure and environmental factors have forced the modern power systems to operate closer to their stability limits. However, maintaining transient stability is a fundamental requirement for the operation of interconnected power systems. In North America, power systems are planned and operated to withstand the loss of any single or multiple elements without violating North American Electric Reliability Corporation (NERC) system performance criteria. For a contingency resulting in the loss of multiple elements (Category C), emergency transient stability controls may be necessary to stabilize the power system. Emergency control is designed to sense abnormal conditions and subsequently take pre-determined remedial actions to prevent instability. Commonly known as either Remedial Action Schemes (RAS) or as Special/System Protection Schemes (SPS), these emergency control approaches have been extensively adopted by utilities. RAS are designed to address specific problems, e.g. to increase power transfer, to provide reactive support, to address generator instability, to limit thermal overloads, etc. Possible remedial actions include generator tripping, load shedding, capacitor and reactor switching, static VAR control, etc. Among various RAS types, generation shedding is the most effective and widely used emergency control means for maintaining system stability. In this dissertation, an optimal power flow (OPF)-based generation-shedding RAS is proposed. This scheme uses online transient stability calculation and generator cost function to determine appropriate remedial actions. For transient stability calculation, SIngle Machine Equivalent (SIME) technique is used, which reduces the multimachine power system model to a One-Machine Infinite Bus (OMIB) equivalent and identifies critical machines. Unlike conventional RAS, which are designed using offline simulations, online stability calculations make the proposed RAS dynamic and adapting to any power system
Transient analysis of a capillary pumped loop heat pipe
Kiper, A. M.; Feric, G.; Anjum, M. I.; Swanson, T. D.
1990-01-01
A bench-top Capillary Pumped Loop (CPL) test system has been developed and tested to investigate the transient mode operation of this system by applying a step power input to the evaporators. Tests were conducted at several power input and evaporator inlet subcooling combinations. In addition, a lumped-heat-capacity model of the CPL test system has been presented which is used for predicting qualitatively the transient operation characteristics. Good agreement has been obtained between the predicted and the measured temperature variations. A simple evaporator inlet subcooler model has also been developed to study effects of inlet subcooling on the steady-state evaporator wall temperature. Results were compared with the test data collected.
Pressure Transient Analysis of Arbitrarily Shaped Fractured Reservoirs
Institute of Scientific and Technical Information of China (English)
Gao Huimei; He Yingfu; Jiang Hanqiao; Chen Minfeng
2007-01-01
Reservoir boundary shape has a great influence on the transient pressure response of oil wells located in arbitrarily shaped reservoirs.Conventional analytical methods can only be used to calculate transient pressure response in regularly shaped reservoirs.Under the assumption that permeability varies exponentially with pressure drop,a mathematical model for well test interpretation of arbitrarily shaped deformable reservoirs was established.By using the regular perturbation method and the boundary element method,the model could be solved.The pressure behavior of wells with wellbore storage and skin effects was obtained by using the Duhamel principle.The type curves were plotted and analyzed by considering the effects of permeability modulus,arbitrary shape and impermeable region.
Fractal analysis of pressure transients in the Geysers Geothermal Field
Energy Technology Data Exchange (ETDEWEB)
Acuna, J.A.; Ershaghi, I.; Yortsos, Y.C.
1992-01-01
The conventionally accepted models for the interpretation of pressure transient tests in naturally fractured reservoirs usually involve simplistic assumptions regarding the geometry and transport properties of the fractured medium. Many single well tests in this type of reservoirs fail to show the predicted behavior for dual or triple porosity or permeability systems and cannot be explained by these models. This paper describes the application of a new model based on a fractal interpretation of the fractured medium. The approach, discussed elsewhere [2], [6], is applied to field data from The Geysers Geothermal Field. The objective is to present an alternative interpretation to well tests that characterizes the fractured medium in a manner more consistent with other field evidence. The novel insight gained from fractal geometry allows the identification of important characteristics of the fracture structure that feeds a particular well. Some simple models are also presented that match the field transient results.
1996-01-01
In a continuing in-house program at the NASA Lewis Research Center, analytical and numerical methods are being developed to apply radiative analysis to predict transient temperature distributions and heat flows in partially transmitting materials. Results have been obtained for a single plane layer, and a transient analysis is being developed for a two-layer composite where each layer has a different refractive index. Because the ceramic refractive indices are larger than one, internal reflections are produced at the surfaces and at the internal interface. Reflections tend to distribute energy within a layer, and this affects the transient temperature distributions.
Materials Analysis of Transient Plasma-Wall Interactions
2014-05-13
model showing the importance sputter and re-deposition. plasma, pulsed plasma, directed energy, transient wall interaction, high energy density...each equipped with a 25kV copper- vapor thyratron start switch capable of sub-microsecond triggering resolution. Each start switch is paired with a...sample exposure positions within the plasma jet. The probe utilizes a PCB Piezotronics model 113B21 pressure sensor modified to work in the plasma jet
Guidelines for transient analysis in water transmission and distribution systems
Pothof, Ivo; Karney, Bryan
2012-01-01
All water systems leak, and many supply systems do so considerably, with water losses typically of approximately 20% of the water production. The IWA Water Loss Task Force aims for a significant reduction of annual water losses by drafting documents to assist practitioners and others to prevent, monitor and mitigate water losses in water transmission and distribution systems. One of the causes of water losses are transient phenomena, caused by normal and accidental pump and valve operations. ...
Transient analysis of an adaptive system for optimization of design parameters
Bayard, D. S.
1992-01-01
Averaging methods are applied to analyzing and optimizing the transient response associated with the direct adaptive control of an oscillatory second-order minimum-phase system. The analytical design methods developed for a second-order plant can be applied with some approximation to a MIMO flexible structure having a single dominant mode.
Computational aspects of sensitivity calculations in transient structural analysis
Greene, William H.; Haftka, Raphael T.
1988-01-01
A key step in the application of formal automated design techniques to structures under transient loading is the calculation of sensitivities of response quantities to the design parameters. This paper considers structures with general forms of damping acted on by general transient loading and addresses issues of computational errors and computational efficiency. The equations of motion are reduced using the traditional basis of vibration modes and then integrated using a highly accurate, explicit integration technique. A critical point constraint formulation is used to place constraints on the magnitude of each response quantity as a function of time. Three different techniques for calculating sensitivities of the critical point constraints are presented. The first two are based on the straightforward application of the forward and central difference operators, respectively. The third is based on explicit differentiation of the equations of motion. Condition errors, finite difference truncation errors, and modal convergence errors for the three techniques are compared by applying them to a simple five-span-beam problem. Sensitivity results are presented for two different transient loading conditions and for both damped and undamped cases.
Analysis of an Earthquake-Initiated-Transient in a PBR
Energy Technology Data Exchange (ETDEWEB)
A. M. Ougouag; J. Ortensi; H. Hiruta
2009-05-01
One of the Design Basis Accidents (DBA) for a Pebble Bed Reactor has been identified as the “Safe shutdown earthquake with core conduction cooling to passive mode of Reactor Cavity Cooling System.” A new methodology to analyze this particular DBA has been developed at the Idaho National Laboratory (INL). During the seismic event the reactor core experiences the densification of the pebbles, which produce small reactivity insertions due to the effective fuel densification. In addition, a decrease in the active core height results in the relative withdrawal of the control rods, which are assumed to remain stationary during the transient. The methodology relies on the dynamic re-meshing of the core during the transient to capture the local packing fraction changes and their corresponding effects on temperature and reactivity. The core re-meshing methodology is based on the velocity profiles of the pebbles in the core, which were obtained with the INL’s pebble mechanics code PEBBLES. The methodology has been added to the coupled code system CYNOD-THERMIX-KONVEK. The reactor power calculation is further improved with the use of the new advanced TRISO fuel model to better approximate the temperatures in the fuel kernels. During the transient the core is brought back to a safe condition by the strong Doppler feedback from local temperature increases.
TRANSIENT HEAT TRANSFER ANALYSIS FOR SRS RADIOACTIVE TANK OPERATION
Energy Technology Data Exchange (ETDEWEB)
Lee, S.
2013-06-27
The primary objective of the present work is to perform a heat balance study for type-I waste tank to assess the impact of using submersible mixer pumps during waste removal. The temperature results calculated by the model will be used to evaluate the temperatures of the slurry waste under various tank operating conditions. A parametric approach was taken to develop a transient model for the heat balance study for type-I waste tanks such as Tank 11, during waste removal by SMP. The tank domain used in the present model consists of two SMP's for sludge mixing, one STP for the waste removal, cooling coil system with 36 coils, and purge gas system. The sludge waste contained in Tank 11 also has a decay heat load of about 43 W/m{sup 3} mainly due to the emission of radioactive gamma rays. All governing equations were established by an overall energy balance for the tank domain, and they were numerically solved. A transient heat balance model used single waste temperature model, which represents one temperature for the entire waste liquid domain contained in the tank at each transient time.
Transient analysis of chilldown in a cryogenic transfer line
Martin, T.
1990-01-01
A numerical model was developed, with the SINDA'85/FLUINT program, for calculating the thermal and hydrodynamic transients that occur during the chilldown of a cryogenic transfer line, using a well documented test case to validate the modeling process. Using this model, a total of ten cases were analyzed to evaluate the effects of variable inlet valve position, inlet pressures, and the use of an internal flow liner to promote nucleate boiling. It was found that an efficient transfer line cooldown can be achieved if the inlet flow is throttled, to reduce the flow rate and quality, and an internal flow liner such as Teflon is used.
An investigation of the transient thermal analysis of spur gears
El-Bayoumy, L. E.; Akin, L. S.; Townsend, D. P.
1984-01-01
A finite element computer program is developed for evaluating the transient behavior of surface temperature in high performance spur gears. The time dimension is implemented using two and three point finite difference schemes. The different schemes are provided for the purpose of numerical stability and convergence studies. A detailed explanation of the gear cooling process leading to the establishment of a modified Blok model is also included. Other conventional models for approximating the heat transfer coefficients are available for comparison. Preliminary results are given showing snap shots of gear temperature contours at the initial stages of tooth engagement.
Finite element approach for transient analysis of multibody systems
Wu, Shih-Chin; Chang, Che-Wei; Housner, Jerrold M.
1992-01-01
A three-dimensional, finite element based formulation for the transient dynamics of constrained multibody systems with trusslike configurations is presented. A convected coordinate system is used to define the rigid-body motion of individual elements in the system. Deformation of each element is defined relative to its convected coordinate system. The formulation is oriented toward joint-dominated structures. Through a series of sequential transformations, the joint degree of freedom is built into the equations of motion of the element to reduce geometric constraints. Based on the derivation, a general-purpose code has been developed. Two examples are presented to illustrate the application of the code.
Analysis of the transient collisional x-ray lasers
Energy Technology Data Exchange (ETDEWEB)
Sasaki, Akira; Utsumi, Takayuki; Moribayashi, Kengo; Zhidkov, Alexei; Kawachi, Tetsuya; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Daido, Hiroyuki [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment
2001-10-01
The spatial and temporal evolution of the gain of a transient collisional x-ray lasers had been investigated using a plasma hydrodynamics code coupled with a detailed atomic kinetics code. The calculated gain of a Ni-like Ag laser pumped by two 100ps laser pulses agrees qualitatively with the experiment. Calculations for a thin foil target irradiated by two 2ps laser pulses shows that a high gain (>50/cm) can be obtained by adjusting the temporal interval between the two pump pulses. (author)
Mo, Qianzhen; Mai, Rongjia; Yang, Zhixiao; Chen, Minfang; Yang, Tiezhao; Lai, Huafang; Yang, Peiliang; Chen, Qiang; Zhou, Xiaohong
2012-06-01
To develop a hydroponic Nicotiana cultivation system for rapid and high-yield transient expression of recombinant proteins under laboratory conditions. To establish the hydroponic cultivation system, several parameters were examined to define the optimal conditions for the expression of recombinant proteins in plants. We used the green fluorescent protein (GFP) and the geminiviral plant transient expression vector as the model protein/expression vector. We examined the impact of Nicotiana species, the density and time of Agrobacterium infiltration, and the post-infiltration growth period on the accumulation of GFP. The expression levels of GFP in Nicotiana leaves were then examined by Western blotting and ELISA. Our data indicated that a hydroponic Nicotiana cultivation system with a light intensity of 9000 LX/layer, a light cycle of 16 h day/8 h night, a temperature regime of 28 degrees celsius; day/21 degrees celsius; night, and a relative humidity of 80% could support the optimal plant growth and protein expression. After agroinfiltration with pBYGFPDsRed.R/LBA4404, high levels of GFP expression were observed in both N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants cultured with this hydroponic cultivation system. An optimal GFP expression was achieved in both Nicotiana species leaves 4 days after infiltration by Agrobacterium with an OD(600) of 0.8. At a given time point, the average biomass of N. tobaccum (cv. Yuyan No.5) was significantly higher than that of N. benthamiana. The leaves from 6-week-old N. benthamiana plants and 5-week-old N. tobaccum (cv. Yuyan No.5) plants could be the optimal material for agroinfiltration. We have established a hydroponic cultivation system that allows robust growth of N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants and the optimal GFP expression in the artificial climate box.
Directory of Open Access Journals (Sweden)
Sunny Katyara
2015-10-01
Full Text Available In this paper analysis and mitigation methods of capacitor bank switching transients on 132KV Grid station, Qasimabad Hyderabad are simulated through the MATLAB software (Matrix Laboratory. Analysis of transients with and without capacitor bank is made. Mathematical measurements of quantities such as transient voltages and inrush currents for each case are discussed. Reasons for these transients, their impact on utility and customer systems and their mitigation are provided.
Sunny Katyara; Ashfaque Ahmed Hashmani; Bhawani Shankar Chowdhry
2015-01-01
In this paper analysis and mitigation methods of capacitor bank switching transients on 132KV Grid station, Qasimabad Hyderabad are simulated through the MATLAB software (Matrix Laboratory). Analysis of transients with and without capacitor bank is made. Mathematical measurements of quantities such as transient voltages and inrush currents for each case are discussed. Reasons for these transients, their impact on utility and customer systems and their mitigation are provided.
Tool for Turbine Engine Closed-Loop Transient Analysis (TTECTrA) Users' Guide
Csank, Jeffrey T.; Zinnecker, Alicia M.
2014-01-01
The tool for turbine engine closed-loop transient analysis (TTECTrA) is a semi-automated control design tool for subsonic aircraft engine simulations. At a specific flight condition, TTECTrA produces a basic controller designed to meet user-defined goals and containing only the fundamental limiters that affect the transient performance of the engine. The purpose of this tool is to provide the user a preliminary estimate of the transient performance of an engine model without the need to design a full nonlinear controller.
Mixed time integration schemes for transient conduction forced-convection analysis
Liu, W. K.; Lin, J. I.
1983-01-01
A partition procedure for forced-convection conduction transient problems is presented. Mixed time partitions are defined wherein coupled conduction force-matrix equations are discretized using an implicit integration method, followed by derivation of a mixed time integration technique. Explicit-implicit and explicit-explicit partitions are performed for a stability analysis for transient conditions, e.g., those found in an actively air-cooled engine and airframe structure.
Computational aspects of sensitivity calculations in linear transient structural analysis
Greene, W. H.; Haftka, R. T.
1991-01-01
The calculation of sensitivities of displacements, velocities, accelerations, and stresses in linear, structural, and transient response problems is studied. Several existing sensitivity calculation methods and two new methods are compared for three example problems. Approximation vectors such as vibration mode shapes are used to reduce the dimensionality of the finite model. To be computationally practical in large-order problems, the overall finite difference methods must use the approximation vectors from the original design in the analyses of the perturbed models. This was found to result in poor convergence of stress sensitivities in several cases. Two semianalytical techniques are developed to overcome this poor convergence. Both new methods result in very good convergence of the stress sensitivities; the computational cost is much less than would result if the vibration modes were recalculated and then used in an overall finite difference method.
Analysis of transient saltwater intrusion in costal aquifers
Chang, Y.; Yeh, H.
2009-12-01
In a costal aquifer, the seawater intrusion is a classic environmental and economical problem in groundwater hydrology. For modeling this phenomenon, the Henry’s formulation was usually adopted to describe the coupled system of flow and transport equations with variable density. However, it is an arduous task to solve such a problem due to the complexity of the coupled governing equations. For practical applicability, the mixed boundary condition which differs from the Dirichlet boundary condition at the coastal side in Henry’s problem is considered in this study. A depth of interface between freshwater and seawater is specified at the coast boundary and the Neumann and Dirichlet conditions are used, respectively, to describe the costal boundary. The perturbation method with a small parameter is used to decouple the groundwater flow and transport equations and derive the solution for the transient saltwater intrusion model. The model will be compared with some results obtained from finite element simulations.
PFR fuel cladding transient test results and analysis
Cannon, N. S.; Hunter, C. W.; Kear, K. L.; Wood, M. H.
1986-05-01
Fuel Cladding Transient Tests (FCTT) were performed on M316 cladding specimens obtained from mixed-oxide fuel pins irradiated in the Prototype Fast Reactor (PFR) to burnups of 4 and 9 atom percent. In these tests, specimens of fuel cladding were pressurized and heated until failure occurred. Samples of cladding from PFR fuel pins exhibited generally greater strength and ductility than specimens from Experimental Breeder Reactor-II (EBR-II) mixed-oxide fuel pins tested under similar conditions. Apparently, the PFR cladding properties were not degraded by a fuel adjacency effect (FAE) observed in fuel pin cladding from EBR-II irradiations. A recently developed model of grain boundary cavity growth was used to predict the results of the tests conducted on PFR cladding. It was found that the predicted failure temperatures for the relevant internal pressures were in good agreement with experimental failure temperatures.
Transient pressure analysis in porous and fractured fractal reservoirs
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Fluid flow in porous and fractured fractal reservoirs is studied in the paper. The basic formulae of seepage velocity,permeability and porosity in both porous and fractured fractal media are developed. The pressure diffusion equation of slightly compressible fluid in fractal reservoirs is derived. The analytical solutions of the transient pressure are given for the line-source well and the well with well-bore storage and skin factor. The typical curves of pressure and the derivative of pressure are established,along with the interpretation of the well-testing method via type-curve matching. In addition,3-D pressure diffusion equations for anisotropic fractal media are given in both Cartesian coordinates and Cy-lindrical coordinates.
Stability Analysis of the LHC Cables for Transient Heat Depositions
Granieri, P P; Xydi, P; Baudouy, B; Bocian, D; Bottura, L; Breschi, M; Siemko, A
2008-01-01
The commissioning and the exploitation of the LHC require a good knowledge of the stability margins of the superconducting magnets with respect to beam induced heat depositions. Previous studies showed that simple numerical models are suitable to carry out stability calculations of multi-strands cables, and highlighted the relevance of the heat transfer model with the surrounding helium. In this paper we present a systematic scan of the stability margin of all types of LHC cables working at 1.9 Kagainst transient heat depositions. We specifically discuss the dependence of the stability margin on the parameters of the model, which provide an estimate of the uncertainty of the values quoted. The stability margin calculations have been performed using a zero-dimensional (0-D) numerical model, and a cooling model taking into account the relevant helium phases which may appear during a stability experiment: it includes Kapitza thermal resistance in superfluid He, boundary layer formation and heat transfer in He I,...
Proteomic tools for the analysis of transient interactions between metalloproteins.
Martínez-Fábregas, Jonathan; Rubio, Silvia; Díaz-Quintana, Antonio; Díaz-Moreno, Irene; De la Rosa, Miguel Á
2011-05-01
Metalloproteins play major roles in cell metabolism and signalling pathways. In many cases, they show moonlighting behaviour, acting in different processes, depending on the physiological state of the cell. To understand these multitasking proteins, we need to discover the partners with which they carry out such novel functions. Although many technological and methodological tools have recently been reported for the detection of protein interactions, specific approaches to studying the interactions involving metalloproteins are not yet well developed. The task is even more challenging for metalloproteins, because they often form short-lived complexes that are difficult to detect. In this review, we gather the different proteomic techniques and biointeractomic tools reported in the literature. All of them have shown their applicability to the study of transient and weak protein-protein interactions, and are therefore suitable for metalloprotein interactions.
Analysis of Transient Behavior of a Vapor Compression Refrigeration Cycle
Fukushima, Toshihiko; Miyamoto, Seigo
A mathematical model for a vapor compression refrigeration cycle for automotive air conditioner is developed, which basically consists of compressor, condenser, receiver, expansion valve, evaporator, suction pressure control valve and piping. The main purpose of this model is to provide the designer with a tool for improving cooling capacity and investigating capacity control of the refrigeration cycle at transient conditions. A lumped parameter system is used for the mathematical model of the condenser and the evaporator, that is obtained with volume integral of the equation of continuity and energy over a bounded volume region. The compressor model and the piping models are also lumped parameter systems, and heat capacity of their walls are taken into account. The theoretical solutions of this model are in good agreement with the experimental results.
Analysis of tracer and thermal transients during reinjection
Energy Technology Data Exchange (ETDEWEB)
Kocabas, I.
1989-10-01
This work studied tracer and thermal transients during reinjection in geothermal reserviors and developed a new technique which combines the results from interwell tracer tests and thermal injection-backflow tests to estimate the thermal breakthrough times. Tracer tests are essential to determine the degree of connectivity between the injection wells and the producing wells. To analyze the tracer return profiles quantitatively, we employed three mathematical models namely, the convection-dispersion (CD) model, matrix diffusion (MD) model, and the Avodnin (AD) model, which were developed to study tracer and heat transport in a single vertical fracture. We considered three types of tracer tests namely, interwell tracer tests without recirculation, interwell tracer tests with recirculation, and injection-backflow tracer tests. To estimate the model parameters, we used a nonlinear regression program to match tracer return profiles to the solutions.
Phytochemical analysis of selected medicinal plants | Hussain ...
African Journals Online (AJOL)
Phytochemical analysis of selected medicinal plants. ... African Journal of Biotechnology ... Abstract. Four medicinal plants including Ranunculus arvensis, Equisetum ravens, Carathamus lanatus and Fagonia critica were used for the study.
NODAL3 Sensitivity Analysis for NEACRP 3D LWR Core Transient Benchmark (PWR
Directory of Open Access Journals (Sweden)
Surian Pinem
2016-01-01
Full Text Available This paper reports the results of sensitivity analysis of the multidimension, multigroup neutron diffusion NODAL3 code for the NEACRP 3D LWR core transient benchmarks (PWR. The code input parameters covered in the sensitivity analysis are the radial and axial node sizes (the number of radial node per fuel assembly and the number of axial layers, heat conduction node size in the fuel pellet and cladding, and the maximum time step. The output parameters considered in this analysis followed the above-mentioned core transient benchmarks, that is, power peak, time of power peak, power, averaged Doppler temperature, maximum fuel centerline temperature, and coolant outlet temperature at the end of simulation (5 s. The sensitivity analysis results showed that the radial node size and maximum time step give a significant effect on the transient parameters, especially the time of power peak, for the HZP and HFP conditions. The number of ring divisions for fuel pellet and cladding gives negligible effect on the transient solutions. For productive work of the PWR transient analysis, based on the present sensitivity analysis results, we recommend NODAL3 users to use 2×2 radial nodes per assembly, 1×18 axial layers per assembly, the maximum time step of 10 ms, and 9 and 1 ring divisions for fuel pellet and cladding, respectively.
Lu, Yuming; Chen, Xi; Wu, Yuxuan; Wang, Yanping; He, Yuqing; Wu, Yan
2013-01-01
A circular plasmid containing a gene coding sequence has been broadly used for studying gene regulation in cells. However, to accommodate a quick screen plasmid construction and preparation can be time consuming. Here we report a PCR amplified dsDNA fragments (PCR-fragments) based transient expression system (PCR-TES) for suiting in the study of gene regulation in plant cells. Instead of transforming plasmids into plant cells, transient expression of PCR-fragments can be applicable. The transformation efficiency and expression property of PCR-fragments are comparable to transformation using plasmids. We analyzed the transformation efficiency in PCR-TES at transcription and protein levels. Our results indicate that the PCR-TES is as versatile as the conventional transformation system using plasmid DNA. Through reconstituting PYR1-mediated ABA signaling pathway in Arabidopsis mesophyll protoplasts, we were not only validating the practicality of PCR-TES but also screening potential candidates of CDPK family members which might be involved in the ABA signaling. Moreover, we determined that phosphorylation of ABF2 by CPK4 could be mediated by ABA-induced PYR1 and ABI1, demonstrating a crucial role of CDPKs in the ABA signaling. In summary, PCR-TES can be applicable to facilitate analyzing gene regulation and for the screen of putative regulatory molecules at the high throughput level in plant cells. PMID:23468926
Directory of Open Access Journals (Sweden)
Yuming Lu
Full Text Available A circular plasmid containing a gene coding sequence has been broadly used for studying gene regulation in cells. However, to accommodate a quick screen plasmid construction and preparation can be time consuming. Here we report a PCR amplified dsDNA fragments (PCR-fragments based transient expression system (PCR-TES for suiting in the study of gene regulation in plant cells. Instead of transforming plasmids into plant cells, transient expression of PCR-fragments can be applicable. The transformation efficiency and expression property of PCR-fragments are comparable to transformation using plasmids. We analyzed the transformation efficiency in PCR-TES at transcription and protein levels. Our results indicate that the PCR-TES is as versatile as the conventional transformation system using plasmid DNA. Through reconstituting PYR1-mediated ABA signaling pathway in Arabidopsis mesophyll protoplasts, we were not only validating the practicality of PCR-TES but also screening potential candidates of CDPK family members which might be involved in the ABA signaling. Moreover, we determined that phosphorylation of ABF2 by CPK4 could be mediated by ABA-induced PYR1 and ABI1, demonstrating a crucial role of CDPKs in the ABA signaling. In summary, PCR-TES can be applicable to facilitate analyzing gene regulation and for the screen of putative regulatory molecules at the high throughput level in plant cells.
Time-Frequency Analysis of Rocket Nozzle Wall Pressures During Start-up Transients
Baars, Woutijn J.; Tinney, Charles E.; Ruf, Joseph H.
2011-01-01
Surveys of the fluctuating wall pressure were conducted on a sub-scale, thrust- optimized parabolic nozzle in order to develop a physical intuition for its Fourier-azimuthal mode behavior during fixed and transient start-up conditions. These unsteady signatures are driven by shock wave turbulent boundary layer interactions which depend on the nozzle pressure ratio and nozzle geometry. The focus however, is on the degree of similarity between the spectral footprints of these modes obtained from transient start-ups as opposed to a sequence of fixed nozzle pressure ratio conditions. For the latter, statistically converged spectra are computed using conventional Fourier analyses techniques, whereas the former are investigated by way of time-frequency analysis. The findings suggest that at low nozzle pressure ratios -- where the flow resides in a Free Shock Separation state -- strong spectral similarities occur between fixed and transient conditions. Conversely, at higher nozzle pressure ratios -- where the flow resides in Restricted Shock Separation -- stark differences are observed between the fixed and transient conditions and depends greatly on the ramping rate of the transient period. And so, it appears that an understanding of the dynamics during transient start-up conditions cannot be furnished by a way of fixed flow analysis.
2014-01-01
The transient behaviors of natural circulation loop (NCL) are important for the system reliability under postulated accidents. The heat loss and structure thermal inertia may influence the transient behaviors of NCL greatly, so a transient analysis model with consideration of heat loss was developed based on the MATLAB/Simulink to predict the thermal-hydraulic characteristic of liquid metal NCL. The transient processes including the start-up, the loss of pump, and the shutdown of thermal-hydr...
Analysis of ventilation systems subjected to explosive transients: far-field analysis
Energy Technology Data Exchange (ETDEWEB)
Tang, P.K.; Andrae, R.W.; Bolstad, J.W.; Duerre, K.H.; Gregory, W.S.
1981-11-01
Progress in developing a far-field explosion simulation computer code is outlined. The term far-field implies that this computer code is suitable for modeling explosive transients in ventilation systems that are far removed from the explosive event and are rather insensitive to the particular characteristics of the explosive event. This type of analysis is useful when little detailed information is available and the explosive event is described parametrically. The code retains all the features of the TVENT code and allows completely compressible flow with inertia and choking effects. Problems that illustrate the capabilities and limitations of the code are described.
Transient analysis and burnout of high temperature superconducting current leads
Seol, S. Y.; Hull, J. R.
The transient behaviour of high-temperature superconductor (HTS) current leads operated between liquid helium and liquid nitrogen temperatures is analysed for burnout conditions upon transition of the HTS into the normal state. Leads composed of HTS only and of HTS sheathed by pure silver or silver alloy are investigated numerically for temperature-dependent properties and analytically for temperature-independent properties. For lower values of shape factor (current density times length), the lead can be operated indefinitely without burnout. At higher values of shape factor, the lead reaches burnout in a finite time. With high current densities, the leads heat adiabatically. For a fixed shape factor, low current densities are desired to achieve long burnout times. To achieve a low helium boil-off rate in the superconducting state without danger of burnout, there is a preferred temperature dependence for thermal conductivity, and silver alloy sheaths are preferred to pure silver sheaths. However, for a given current density, pure silver sheaths take longer to burn out.
Numerical Analysis of Transient Temperature Response of Soap Film
Tanaka, Seiichi; Tatesaku, Akihiro; Dantsuka, Yuki; Fujiwara, Seiji; Kunimine, Kanji
2015-11-01
Measurements of thermophysical properties of thin liquid films are important to understand interfacial phenomena due to film structures composed of amphiphilic molecules in soap film, phospholipid bilayer of biological cell and emulsion. A transient hot-wire technique for liquid films less than 1 \\upmu m thick such as soap film has been proposed to measure the thermal conductivity and diffusivity simultaneously. Two-dimensional heat conduction equations for a solid cylinder with a liquid film have been solved numerically. The temperature of a thin wire with liquid film increases steeply with its own heat generation. The feasibility of this technique is verified through numerical experiments for various thermal conductivities, diffusivities, and film thicknesses. Calculated results indicate that the increase in the volumetric average temperature of the thin wire sufficiently varies with the change of thermal conductivity and diffusivity of the soap film. Therefore, the temperature characteristics could be utilized to evaluate both the thermal conductivity and diffusivity using the Gauss-Newton method.
Transient Thermal Analysis of a Refractive Secondary Solar Concentrator
Geng, Steven M.; Macosko, Robert P.
1999-01-01
A secondary concentrator is an optical device that accepts solar energy from a primary concentrator and further intensifies and directs the solar flux. The refractive secondary is one such device; fabricated from an optically clear solid material that can efficiently transmit the solar energy by way of refraction and total internal reflection. When combined with a large state-of-the-art rigid or inflatable primary concentrator, the refractive secondary enables solar concentration ratios of 10,000 to 1. In support of potential space solar thermal power and propulsion applications, the NASA Glenn Research Center is developing a single-crystal refractive secondary concentrator for use at temperatures exceeding 2000K. Candidate optically clear single-crystal materials like sapphire and zirconia are being evaluated for this application. To support this evaluation, a three-dimensional transient thermal model of a refractive secondary concentrator in a typical solar thermal propulsion application was developed. This paper describes the model and presents thermal predictions for both sapphire and zirconia prototypes. These predictions are then used to establish parameters for analyzing and testing the materials for their ability to survive thermal shock and stress.
Transient-based analysis for the detection of broken damper bars in synchronous motors
Antonino-Daviu, J. A.; Climente-Alarcón, V.; Pons-Llinares, J.; Puche, R.; Pineda-Sánchez, M.
2013-01-01
Synchronous generators and motors constitute critical elements in power generation plants and certain industrial facilities. Damper bars are crucial components of most of these synchronous machines. They enable, among other functions, the direct-on-line starting of these machines, just as if they were asynchronous. Some recent cases, reported by several authors, have demonstrated that eventual failure of damper bars is possible, mainly due to the currents and stresses rising during their operation. In this context, the development of reliable techniques able to diagnose possible damper breakages has attracted significant interest within the fault diagnosis area. The present paper proposes the application of a novel transient-based methodology to diagnose broken damper bars in synchronous motors. This methodology was previously assessed with success in industrial induction motors with diverse sizes. The approach relies on the analysis of the stator startup current demanded by the machine during a direct-on-line starting. To this end, suitable time-frequency decomposition tools are used. In this particular work, the Discrete Wavelet Transform (DWT) is proposed, due to its simplicity, low computational requirements and easy interpretation of its results. Simulation and experimental results obtained with laboratory synchronous machines confirm the validity of the approach for condition monitoring of such windings.
Ding, Ming; Zhu, Qianlong
2016-01-01
Hardware protection and control action are two kinds of low voltage ride-through technical proposals widely used in a permanent magnet synchronous generator (PMSG). This paper proposes an innovative clustering concept for the equivalent modeling of a PMSG-based wind power plant (WPP), in which the impacts of both the chopper protection and the coordinated control of active and reactive powers are taken into account. First, the post-fault DC link voltage is selected as a concentrated expression of unit parameters, incoming wind and electrical distance to a fault point to reflect the transient characteristics of PMSGs. Next, we provide an effective method for calculating the post-fault DC link voltage based on the pre-fault wind energy and the terminal voltage dip. Third, PMSGs are divided into groups by analyzing the calculated DC link voltages without any clustering algorithm. Finally, PMSGs of the same group are equivalent as one rescaled PMSG to realize the transient equivalent modeling of the PMSG-based WPP. Using the DIgSILENT PowerFactory simulation platform, the efficiency and accuracy of the proposed equivalent model are tested against the traditional equivalent WPP and the detailed WPP. The simulation results show the proposed equivalent model can be used to analyze the offline electromechanical transients in power systems.
2016-06-01
due to the highly technical and frequently changing regulations that govern contracting operations. Figure 2. Question 2 Survey Response Chart ...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA JOINT APPLIED PROJECT USMC CONTINGENCY CONTRACTING FORCE: AN ANALYSIS OF...CONTINGENCY CONTRACTING FORCE: AN ANALYSIS OF TRANSIENT OFFICERS IN A RAPIDLY CHANGING ACQUISITION ENVIRONMENT 5. FUNDING NUMBERS 6. AUTHOR(S) Adam
Transient thermal analysis as measurement method for IC package structural integrity
Hanß, Alexander; Schmid, Maximilian; Liu, E.; Elger, Gordon
2015-06-01
Practices of IC package reliability testing are reviewed briefly, and the application of transient thermal analysis is examined in great depth. For the design of light sources based on light emitting diode (LED) efficient and accurate reliability testing is required to realize the potential lifetimes of 105 h. Transient thermal analysis is a standard method to determine the transient thermal impedance of semiconductor devices, e.g. power electronics and LEDs. The temperature of the semiconductor junctions is assessed by time-resolved measurement of their forward voltage (Vf). The thermal path in the IC package is resolved by the transient technique in the time domain. This enables analyzing the structural integrity of the semiconductor package. However, to evaluate thermal resistance, one must also measure the dissipated energy of the device (i.e., the thermal load) and the k-factor. This is time consuming, and measurement errors reduce the accuracy. To overcome these limitations, an innovative approach, the relative thermal resistance method, was developed to reduce the measurement effort, increase accuracy and enable automatic data evaluation. This new way of evaluating data simplifies the thermal transient analysis by eliminating measurement of the k-factor and thermal load, i.e. measurement of the lumen flux for LEDs, by normalizing the transient Vf data. This is especially advantageous for reliability testing where changes in the thermal path, like cracks and delaminations, can be determined without measuring the k-factor and thermal load. Different failure modes can be separated in the time domain. The sensitivity of the method is demonstrated by its application to high-power white InGaN LEDs. For detailed analysis and identification of the failure mode of the LED packages, the transient signals are simulated by time-resolved finite element (FE) simulations. Using the new approach, the transient thermal analysis is enhanced to a powerful tool for reliability
A Coupled Calculation Suite for Atucha II Operational Transients Analysis
Directory of Open Access Journals (Sweden)
Oscar Mazzantini
2011-01-01
Full Text Available While more than a decade ago reactor and thermal hydraulic calculations were tedious and often needed a lot of approximations and simplifications that forced the designers to take a very conservative approach, computational resources available nowadays allow engineers to cope with increasingly complex problems in a reasonable time. The use of best-estimate calculations provides tools to justify convenient engineering margins, reduces costs, and maximises economic benefits. In this direction, a suite of coupled best-estimate specific calculation codes was developed to analyse the behaviour of the Atucha II nuclear power plant in Argentina. The developed tool includes three-dimensional spatial neutron kinetics, a channel-level model of the core thermal hydraulics with subcooled boiling correlations, a one-dimensional model of the primary and secondary circuits including pumps, steam generators, heat exchangers, and the turbine with all their associated control loops, and a complete simulation of the reactor control, limitation, and protection system working in closed-loop conditions as a faithful representation of the real power plant. In the present paper, a description of the coupling scheme between the codes involved is given, and some examples of their application to Atucha II are shown.
Directory of Open Access Journals (Sweden)
Muhammad Aleem Ashraf
2014-01-01
Full Text Available The C1 promoter expressing the AC1 gene, and V1 promoter expressing the AV1 gene are located in opposite orientations in the large intergenic region of the Cotton leaf curl Burewala virus (CLCuBuV genome. Agro-infiltration was used to transiently express putative promoter constructs in Nicotiana tabacum and Gossypium hirsutum leaves, which was monitored by a GUS reporter gene, and revealed that the bidirectional promoter of CLCuBuV transcriptionally regulates both the AC1 and AV1 genes. The CLCuBuV C1 gene promoter showed a strong, consistent transient expression of the reporter gene (GUS in N. tabacum and G. hirsutum leaves and exhibited GUS activity two- to three-fold higher than the CaMV 35S promoter. The CLCuBuV bidirectional gene promoter is a nearly constitutive promoter that contains basic conserved elements. Many cis-regulatory elements (CREs were also analyzed within the bidirectional plant promoters of CLCuBuV and closely related geminiviruses, which may be helpful in understanding the transcriptional regulation of both the virus and host plant.
Transient Analysis of Monopile Foundations Partially Embedded in Liquefied Soil
DEFF Research Database (Denmark)
Barari, Amin; Bayat, Mehdi; Meysam, Saadati
2015-01-01
In this study, the authors present a coupled fluid-structures-seabed interaction analysis of a monopile type of wind turbine foundations in liquefiable soils. A two dimensional analysis is performed with a nonlinear stiffness degradation model incorporated in the finite difference program Fast La...
POEAS: Automated Plant Phenomic Analysis Using Plant Ontology.
Shameer, Khader; Naika, Mahantesha Bn; Mathew, Oommen K; Sowdhamini, Ramanathan
2014-01-01
Biological enrichment analysis using gene ontology (GO) provides a global overview of the functional role of genes or proteins identified from large-scale genomic or proteomic experiments. Phenomic enrichment analysis of gene lists can provide an important layer of information as well as cellular components, molecular functions, and biological processes associated with gene lists. Plant phenomic enrichment analysis will be useful for performing new experiments to better understand plant systems and for the interpretation of gene or proteins identified from high-throughput experiments. Plant ontology (PO) is a compendium of terms to define the diverse phenotypic characteristics of plant species, including plant anatomy, morphology, and development stages. Adoption of this highly useful ontology is limited, when compared to GO, because of the lack of user-friendly tools that enable the use of PO for statistical enrichment analysis. To address this challenge, we introduce Plant Ontology Enrichment Analysis Server (POEAS) in the public domain. POEAS uses a simple list of genes as input data and performs enrichment analysis using Ontologizer 2.0 to provide results in two levels, enrichment results and visualization utilities, to generate ontological graphs that are of publication quality. POEAS also offers interactive options to identify user-defined background population sets, various multiple-testing correction methods, different enrichment calculation methods, and resampling tests to improve statistical significance. The availability of such a tool to perform phenomic enrichment analyses using plant genes as a complementary resource will permit the adoption of PO-based phenomic analysis as part of analytical workflows. POEAS can be accessed using the URL http://caps.ncbs.res.in/poeas.
Energy Technology Data Exchange (ETDEWEB)
Lee, Kyung-Ho; Lee, Sang-Jin; Kim, Jeong-Mook [Nuclear Engineering and Technology Institute, Daejeon (Korea, Republic of)
2007-07-01
This paper covers the heat transfer analysis in MACSTOR/KN-400 on a basis of transient state. Transient state reflects actual operation conditions such as solar loads, daily temperature variations. The heat transfer analysis has usually been performed under steady state, but transient state would be considered as crucial factor in thermal analysis in the future. Therefore, much attention needs to be paid on how transient effect affects the results of heat transfer. Analysis model includes all parts of concrete module consisting of wall, top slab and storage cylinders.
Transient Safety Analysis of Fast Spectrum TRU Burning LWRs with Internal Blankets
Energy Technology Data Exchange (ETDEWEB)
Downar, Thomas [Univ. of Michigan, Ann Arbor, MI (United States); Zazimi, Mujid [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Hill, Bob [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-01-31
The objective of this proposal was to perform a detailed transient safety analysis of the Resource-Renewable BWR (RBWR) core designs using the U.S. NRC TRACE/PARCS code system. This project involved the same joint team that has performed the RBWR design evaluation for EPRI and therefore be able to leverage that previous work. And because of their extensive experience with fast spectrum reactors and parfait core designs, ANL was also part the project team. The principal outcome of this project was the development of a state-of-the-art transient analysis capability for GEN-IV reactors based on Monte Carlo generated cross sections and the US NRC coupled code system TRACE/PARCS, and a state-of-the-art coupled code assessment of the transient safety performance of the RBWR.
Transient Voltage Stability Analysis and Improvement of A Network with different HVDC Systems
DEFF Research Database (Denmark)
Liu, Yan; Chen, Zhe
2011-01-01
the theoretical analysis and the improved control method, real time simulation model of a hybrid multi-infeed HVDC system based on western Danish power system is established in RTDS™. Simulation results show that the enhanced transient voltage stability can be achieved.......This paper presents transient voltage stability analysis of an AC system with multi-infeed HVDC links including a traditional LCC HVDC link and a VSC HVDC link. It is found that the voltage supporting capability of the VSC-HVDC link is significantly influenced by the tie-line distance between...... the two links and the size of loads. In order to improve the transient voltage stability, a voltage adjusting method is proposed in this paper. A voltage increment component has been introduced into the outer voltage control loop under emergency situation caused by severe grid faults. In order to verify...
Energy Technology Data Exchange (ETDEWEB)
Bartlett, E.B.; Danofsky, R.; Adams, J.; AlJundi, T.; Basu, A.; Dhanwada, C.; Kerr, J.; Kim, K.; Lanc, T.
1993-02-23
The objective of this report is to describe results obtained during the first year of funding that will lead to the development of an artificial neural network (ANN) fault - diagnostic system for the real - time classification of operational transients at nuclear power plants. The ultimate goal of this three-year project is to design, build, and test a prototype diagnostic adviser for use in the control room or technical support center at Duane Arnold Energy Center (DAEC); such a prototype could be integrated into the plant process computer or safety - parameter display system. The adviser could then warn and inform plant operators and engineers of plant component failures in a timely manner. This report describes the work accomplished in the first of three scheduled years for the project. Included herein is a summary of the first year`s results as, well as individual descriptions of each of the major topics undertaken by the researchers. Also included are reprints of the articles written under this funding as well as those that were published during the funded period.
Energy Technology Data Exchange (ETDEWEB)
Ferng, Y.M., E-mail: ymferng@ess.nthu.edu.t [Department of Engineering and System Science, Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2. Kuang-Fu Rd., Hsinchu 30013, Taiwan (China); Liu, C.H. [Department of Engineering and System Science, Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2. Kuang-Fu Rd., Hsinchu 30013, Taiwan (China)
2011-01-15
Burning characteristics of electrical cables are one of the key parameters for the fire hazard assessment of nuclear power plants (NPPs) since the cables are the essential sources of fire in the plants. A three-dimensional (3-D) transient computational fluid dynamics (CFD) code{sub F}DS is adopted in this paper to simulate these characteristics related to the cable burning. Being one of the NRC licensing fire codes, the FDS includes the thermal-hydraulic equations, the turbulence model and the chemical combustion model, etc. In order to assess the CFD fire models used in this code, a burning test using the control cable with the outer jacket of polyvinylchloride (PVC) and the inner insulation of cross-linked polyethylene (XLPE) is conducted. The measured parameters associated with the burning characteristics include the heat release rate (HRR), O{sub 2} depletion, and CO and CO{sub 2} production, etc. Except the amount of O{sub 2} consumption, the predicted transient behaviors of other parameters can reproduce the measured data. Based on the chemical combustion model in the FDS code, this discrepancy may be essentially resulted from the default value of hydrogen fraction (H{sub frac}) contained in the soot since the soot yield for the burning of PVC material is high enough that the uncertainty in the H{sub frac} value has a prominent effect on the amount of O{sub 2} consumption. This explanation can be confirmed by a benchmark calculation for simulating a burning test with the polymethylmethacrylate (PMMA) fuel of low-soot yield. The present simulation works can provide the useful information for the plant staff or the researcher as they would perform the fire hazard analysis in the NPPs using the FDS code.
Transient and stability analysis of a BWR core with thorium-uranium fuel
Energy Technology Data Exchange (ETDEWEB)
Nunez-Carrera, Alejandro [Comision Nacional de Seguridad Nuclear y Salvaguardias, Dr. Barragan 779 Col. Narvarte, 03020 Mexico, DF (Mexico); Espinosa-Paredes, Gilberto [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana, Av. San Rafael Atlixco 186, Col. Vicentina, 09340 Mexico, DF (Mexico)], E-mail: gepe@xanum.uam.mx; Francois, Juan-Luis [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532, 62550 Jiutepec Mor. (Mexico)
2008-08-15
The kinetic response of a boiling water reactor (BWR) equilibrium core using thorium as a nuclear material, in an integrated blanket-seed assembly, is presented in this work. Additionally an in-house code was developed to evaluate this core under steady state and transient conditions including a stability analysis. The code has two modules: (a) the time domain module for transient analysis and (b) the frequency domain module for stability analysis. The thermal-hydraulic process is modeled by a set of five equations, considering no homogeneous flow with drift-flux approximation and non-equilibrium thermodynamic. The neutronic process is calculated with a point kinetics model. Typical BWR reactivity effects are considered: void fraction, fuel temperature, moderator temperature and control rod density. Collapsed parameters were included in the code to represent the core using an average fuel channel. For the stability analysis, in the frequency domain, the transfer function is determined by applying Laplace-transforming to the calculated pressure drop perturbations in each of the considered regions where a constant total pressure drop was considered. The transfer function was used to study the system response in the frequency domain when an inlet flow perturbation is applied. The results show that the neutronic behavior of the core with thorium uranium fuel is similar to a UO{sub 2} core, even during transient conditions. The stability and transient analysis show that the thorium-uranium fuel can be operated safely in current BWRs.
Noureldin, K.; González-Escalada, L. M.; Hirsch, T.; Nouri, B.; Pitz-Paal, R.
2016-05-01
A large number of commercial and research line focusing solar power plants are in operation and under development. Such plants include parabolic trough collectors (PTC) or linear Fresnel using thermal oil or molten salt as the heat transfer medium (HTM). However, the continuously varying and dynamic solar condition represent a big challenge for the plant control in order to optimize its power production and to keep the operation safe. A better understanding of the behaviour of such power plants under transient conditions will help reduce defocusing instances, improve field control, and hence, increase the energy yield and confidence in this new technology. Computational methods are very powerful and cost-effective tools to gain such understanding. However, most simulation models described in literature assume equal mass flow distributions among the parallel loops in the field or totally decouple the flow and thermal conditions. In this paper, a new numerical model to simulate a whole solar field with single-phase HTM is described. The proposed model consists of a hydraulic part and a thermal part that are coupled to account for the effect of the thermal condition of the field on the flow distribution among the parallel loops. The model is specifically designed for large line-focusing solar fields offering a high degree of flexibility in terms of layout, condition of the mirrors, and spatially resolved DNI data. Moreover, the model results have been compared to other simulation tools, as well as experimental and plant data, and the results show very good agreement. The model can provide more precise data to the control algorithms to improve the plant control. In addition, short-term and accurate spatially discretized DNI forecasts can be used as input to predict the field behaviour in-advance. In this paper, the hydraulic and thermal parts, as well as the coupling procedure, are described and some validation results and results of simulating an example field are
de Palézieux, Larissa; Loew, Simon; Zwahlen, Peter
2016-04-01
Many mountain slopes in the Alps exhibit large compound rock slides or Deep Seated Gravitational Slope Deformations. Due to the basal rupture plane geometry and the cumulative displacement magnitude such landslide bodies are often strongly deformed, highly fractured and - at least locally - very permeable. This can lead to high infiltration rates and low phreatic groundwater tables. This is also the situation in the studied mountain slopes southwest of Poschiavo, where large suspended rockslides occur, with very little surface runoff at high elevations, and torrents developing only at the elevation of the basal rupture planes. Below the landslide toes, at altitudes below ca. 1700 m a.s.l., groundwater appears forming spring lines or distributed spring clusters. Within the scope of the design of a hydropower pump storage plant in the Poschiavo valley by Lagobianco SA (Repower AG), numerous cored and deep boreholes (of 50 to 300 m depth) have been drilled along the planned pressure tunnel alignement at elevations ranging from 963 to 2538 m a.s.l. in the years 2010 and 2012. In several boreholes Lugeon and transient pressure tests were executed and pore water pressure sensors installed in short monitoring sections at various depths. Most of these boreholes intersect deep rockslides in crystalline rocks and limestones, showing highly fragmented rock masses and cohesionless cataclastic shear zones of several tens of meters thickness. This study explores these borehole observations in landslides and adjacent stable slopes and links them to the general hydrologic and hydrogeologic framework. The analysis of the pore water pressure data shows significant variability in seasonal trends and short-term events (from snow melt and summer rain storms) and remarkable pressure differences over short horizontal and vertical distances. This reflects rock mass damage within landslide bodies and important sealing horizons at their base. Based on water balances, the estimated effective
Calibration of transient groundwater models using time series analysis and moment matching
Bakker, M.; Maas, K.; Von Asmuth, J.R.
2008-01-01
A comprehensive and efficient approach is presented for the calibration of transient groundwater models. The approach starts with the time series analysis of the measured heads in observation wells using all active stresses as input series, which may include rainfall, evaporation, surface water leve
Transient analysis techniques in performing impact and crash dynamic studies
Pifko, A. B.; Winter, R.
1989-01-01
Because of the emphasis being placed on crashworthiness as a design requirement, increasing demands are being made by various organizations to analyze a wide range of complex structures that must perform safely when subjected to severe impact loads, such as those generated in a crash event. The ultimate goal of crashworthiness design and analysis is to produce vehicles with the ability to reduce the dynamic forces experienced by the occupants to specified levels, while maintaining a survivable envelope around them during a specified crash event. DYCAST is a nonlinear structural dynamic finite element computer code that started from the plans systems of a finite element program for static nonlinear structural analysis. The essential features of DYCAST are outlined.
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
Institute of Scientific and Technical Information of China (English)
YIN Hong-jun; HE Ying-fu; FU Chun-quan
2005-01-01
The transient flow mathematical model of arbitrary shaped heterogeneous reservoirs with impermeability barrier is proposed in this paper. In order to establish this model, the perturbation method is employed and the solution of model is expanded into a series in powers of perturbation parameter. By using the Boundary Element Method (BEM) and Duhamel principle, wellbore pressure with effects of skins and wellbore storage is obtained. The type curves are plotted and analyzed considering effects of heterogeneity, arbitrary shape and impermeable barriers. Finally, the results obtained by perturbation boundary element method is compared with the analytical solution and is available for the transient pressure analysis of arbitrary shaped reservoirs.
Inverse Transient Analysis for Classification of Wall Thickness Variations in Pipelines
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
Padovan, Joe
1987-01-01
In a three-part series of papers, a generalized finite element analysis scheme is developed to handle the steady and transient response of moving/rolling nonlinear viscoelastic structure. This paper considers the development of the moving/rolling element strategy, including the effects of large deformation kinematics and viscoelasticity modeled by fractional integrodifferential operators. To improve the solution strategy, a special hierarchical constraint procedure is developed for the case of steady rolling/translating, as well as a transient scheme involving the use of a Grunwaldian representation of the fractional operator.
Sellers, J. F.
1973-01-01
The transient performance of two concepts for control of vertical takeoff aircraft remote lift fans is analyzed and discussed. Both concepts employ flow transfer between pairs of lift fans located in separate parts of the aircraft in order to obtain attitude control moments for hover and low-speed flight. The results presented are from a digital computer, dynamic analysis of the YJ97/LF460 remote drive turbofan. The transient responses of the two systems are presented for step demands in lift and moment.
3D TRANSIENT COUPLED THERMO-ELASTIC-PLASTIC CONTACT SEALING ANALYSIS OF REACTOR PRESSURE VESSEL
Institute of Scientific and Technical Information of China (English)
Du Xuesong; Li Runfang; Lin Tengjiao
2005-01-01
Sealing analysis of sealing system in reactor pressure vessels is relevant with multiple nonlinear coupled-field effects, so even large-scale commercial finite element software cannot finish the complicated analysis. A fmite element method of 3D transient coupled thermo-elastic-plastic contact sealing analysis for reactor pressure vessels is presented, in which the surface nonlinearity,material nonlinearity, transient heat transfer nonlinearity and multiple coupled effect are taken into account and the sealing equation is coupling solved in iterative procedure. At the same time, a computational analysis program is developed, which is applied in the sealing analysis of experimental reactor pressure vessel, and the numerical results are in good coincidence with the experimental results. This program is also successful in analyzing the practical problem in engineering.
Dynamic metabolic flux analysis--tools for probing transient states of metabolic networks.
Antoniewicz, Maciek R
2013-12-01
Computational approaches for analyzing dynamic states of metabolic networks provide a practical framework for design, control, and optimization of biotechnological processes. In recent years, two promising modeling approaches have emerged for characterizing transients in cellular metabolism, dynamic metabolic flux analysis (DMFA), and dynamic flux balance analysis (DFBA). Both approaches combine metabolic network analysis based on pseudo steady-state (PSS) assumption for intracellular metabolism with dynamic models for extracellular environment. One strategy to capture dynamics is by combining network analysis with a kinetic model. Predictive models are thus established that can be used to optimize bioprocessing conditions and identify useful genetic manipulations. Alternatively, by combining network analysis with methods for analyzing extracellular time-series data, transients in intracellular metabolic fluxes can be determined and applied for process monitoring and control.
Directory of Open Access Journals (Sweden)
Masaru Ishizuka
2011-01-01
Full Text Available In recent years, there is a growing demand to have smaller and lighter electronic circuits which have greater complexity, multifunctionality, and reliability. High-density multichip packaging technology has been used in order to meet these requirements. The higher the density scale is, the larger the power dissipation per unit area becomes. Therefore, in the designing process, it has become very important to carry out the thermal analysis. However, the heat transport model in multichip modules is very complex, and its treatment is tedious and time consuming. This paper describes an application of the thermal network method to the transient thermal analysis of multichip modules and proposes a simple model for the thermal analysis of multichip modules as a preliminary thermal design tool. On the basis of the result of transient thermal analysis, the validity of the thermal network method and the simple thermal analysis model is confirmed.
Analysis of a Microgrid under Transient Conditions Using Voltage and Frequency Controller
Directory of Open Access Journals (Sweden)
Monika Jain
2012-01-01
Full Text Available This paper presents an investigation of voltage-and-frequency-(VF- based battery energy storage system (BESS controller used in micro grid for analyzing the optimum capability of plant. Microgrid is formed by using three hydropower plants feeding three-phase four-wire load. The proposed controller is used for load balancing, harmonic elimination, load leveling, and neutral current compensation. The proposed BESS controller permits the selection of an optimum voltage level of battery and allows independent current control of each phase. The main emphasis is given on maintaining constant voltage and frequency within the micro grid during transient conditions. Micro grid with power plant and its controller is modeled in MATLAB/Simulink using Power System Blockset (PSB toolboxes.
Dynamical analysis of innovative core designs facing unprotected transients with the MAT5 DYN code
Energy Technology Data Exchange (ETDEWEB)
Darmet, G.; Massara, S. [EDF R and D, 1 avenue du general de Gaulle, 92140 Clamart (France)
2012-07-01
Since 2007, advanced Sodium-cooled Fast Reactors (SFR) are investigated by CEA, AREVA and EDF in the framework of a joint French collaboration. A prototype called ASTRID, sets out to demonstrate progress made in SFR technology, is due to operate in the years 2020's. The modeling of unprotected transients by computer codes is one of the key safety issues in the design approach to such SFR systems. For that purpose, the activity on CATHARE, which is the reference code for the transient analysis of ASTRID, has been strengthened during last years by CEA. In the meantime, EDF has developed a simplified and multi-channel code, named MAT5 DYN, to analyze and validate innovative core designs facing protected and unprotected transients. First, the paper consists in a description of MAT5 DYN: a code based on the existing code MAT4 DYN including major improvements on geometry description and physical modeling. Second, two core designs based on the CFV core design developed at CEA are presented. Then, the dynamic response of those heterogeneous cores is analyzed during unprotected loss of flow (ULOF) transient and unprotected transient of power (UTOP). The results highlight the importance of the low void core effect specific to the CFV design. Such an effect, when combined with a sufficient primary pump halving time and an optimized cooling group scheme, allows to delay (or, possibly, avoid) the sodium boiling onset during ULOF accidents. (authors)
Nuclear reactor transient analysis via a quasi-static kinetics Monte Carlo method
Jo, YuGwon; Cho, Bumhee; Cho, Nam Zin
2015-12-01
The predictor-corrector quasi-static (PCQS) method is applied to the Monte Carlo (MC) calculation for reactor transient analysis. To solve the transient fixed-source problem of the PCQS method, fission source iteration is used and a linear approximation of fission source distributions during a macro-time step is introduced to provide delayed neutron source. The conventional particle-tracking procedure is modified to solve the transient fixed-source problem via MC calculation. The PCQS method with MC calculation is compared with the direct time-dependent method of characteristics (MOC) on a TWIGL two-group problem for verification of the computer code. Then, the results on a continuous-energy problem are presented.
Nuclear reactor transient analysis via a quasi-static kinetics Monte Carlo method
Energy Technology Data Exchange (ETDEWEB)
Jo, YuGwon; Cho, Bumhee; Cho, Nam Zin, E-mail: nzcho@kaist.ac.kr [Korea Advanced Institute of Science and Technology 291 Daehak-ro, Yuseong-gu, Daejeon, Korea 305-701 (Korea, Republic of)
2015-12-31
The predictor-corrector quasi-static (PCQS) method is applied to the Monte Carlo (MC) calculation for reactor transient analysis. To solve the transient fixed-source problem of the PCQS method, fission source iteration is used and a linear approximation of fission source distributions during a macro-time step is introduced to provide delayed neutron source. The conventional particle-tracking procedure is modified to solve the transient fixed-source problem via MC calculation. The PCQS method with MC calculation is compared with the direct time-dependent method of characteristics (MOC) on a TWIGL two-group problem for verification of the computer code. Then, the results on a continuous-energy problem are presented.
Padovan, Joe
1986-01-01
In a three part series of papers, a generalized finite element analysis scheme is developed to handle the steady and transient response of moving/rolling nonlinear viscoelastic structure. This paper considers the development of the moving/rolling element strategy, including the effects of large deformation kinematics and viscoelasticity modelled by fractional integro-differential operators. To improve the solution strategy, a special hierarchical constraint procedure is developed for the case of steady rolling/translating as well as a transient scheme involving the use of a Grunwaldian representation of the fractional operator. In the second and third parts of the paper, 3-D extensions are developed along with transient contact strategies enabling the handling of impacts with obstructions. Overall, the various developments are benchmarked via comprehensive 2- and 3-D simulations. These are correlated with experimental data to define modelling capabilities.
Transient Current Analysis of Induction Generators for Wind Power Generating System
Senjyu, Tomonobu; Sueyoshi, Norihide; Uezato, Katsumi; Fujita, Hideki
In recent year, non-conventional energy generation is coming up for effective use of natural energy, such as wind energy. Induction generators consisting squirrel-cage rotors are widly used as wind generators because of their salient features like robust rotor design, simple in the construction, maintenance free operation, etc. However these induction generators will draw large transient inrush current, several times as large as the machine rated current, the instant when they are connected to utility grid or restored after the fault clearance. Under such situations, there will be a severe voltage fluctuations in the power system. In this paper, we present transient analysis of induction generators before and after a three-phase fault conditions. Theoretical discission is developed to determine the initial phase angle and the time at which maximum transient currents flow in the system.
Quantitative numerical analysis of transient IR-experiments on buildings
Maierhofer, Ch.; Wiggenhauser, H.; Brink, A.; Röllig, M.
2004-12-01
Impulse-thermography has been established as a fast and reliable tool in many areas of non-destructive testing. In recent years several investigations have been done to apply active thermography to civil engineering. For quantitative investigations in this area of application, finite difference calculations have been performed for systematic studies on the influence of environmental conditions, heating power and time, defect depth and size and thermal properties of the bulk material (concrete). The comparison of simulated and experimental data enables the quantitative analysis of defects.
New pressure transient analysis methods for naturally fractured reservoirs
Energy Technology Data Exchange (ETDEWEB)
Serra, K.; Raghavan, R.; Reynolds, A.C.
1983-10-01
This paper presents new methods for analyzing pressure drawdown and buildup data obtained at wells producing naturally fractured reservoirs. The model used in this study assumes unsteady-state fluid transfer from the matrix system to the fracture system. A new flow regime is identified. The discovery of this flow regime explains field behavior that has been considered unusual. The probability of obtaining data reflecting this flow regime in a field test is higher than that of obtaining the classical responses given in the literature. The identification of this new flow regime provides methods for preparing a complete analysis of pressure data obtained from naturally fractured reservoirs. Applications to field data are discussed.
New pressure transient analysis methods for naturally fractured reservoirs
Energy Technology Data Exchange (ETDEWEB)
Serra, K.; Raghavan, R.; Reynolds, A.C.
1983-12-01
This paper presents new methods for analyzing pressure drawdown and buildup data obtained at wells producing naturally fractured reservoirs. The model used in this study assumes unsteady-state fluid transfer from the matrix system to the fracture system. A new flow regime is identified. The discovery of this flow regime explains field behavior that has been considered unusual. The probability of obtaining data reflecting this flow regime in a field test is higher than that of obtaining the classical responses given in the literature. The identification of this new flow regime provides methods for preparing a complete analysis of pressure data obtained from naturally fractured reservoirs. Applications to field data are discussed.
Energy Technology Data Exchange (ETDEWEB)
Kot, C A; Youngdahl, C K
1978-09-01
PTAC was developed to predict pressure transients in nuclear-power-plant piping systems in which the possibility of cavitation must be considered. The program performs linear or nonlinear fluid-hammer calculations, using a fixed-grid method-of-characteristics solution procedure. In addition to pipe friction and elasticity, the program can treat a variety of flow components, pipe junctions, and boundary conditions, including arbitrary pressure sources and a sodium/water reaction. Essential features of transient cavitation are modeled by a modified column-separation technique. Comparisons of calculated results with available experimental data, for a simple piping arrangement, show good agreement and provide validation of the computational cavitation model. Calculations for a variety of piping networks, containing either liquid sodium or water, demonstrate the versatility of PTAC and clearly show that neglecting cavitation leads to erroneous predictions of pressure-time histories.
Pressure transient analysis of two-phase flow problems
Energy Technology Data Exchange (ETDEWEB)
Chu, W.C.; Reynolds, A.C.; Raghavan, R.
1986-04-01
This paper considers the analysis of pressure drawdown and buildup data for two-phase flow problems. Of primary concern is the analysis of data influenced by saturation gradients that exist within the reservoir. Wellbore storage effects are assumed to be negligible. The pressure data considered are obtained from a two-dimensional (2D) numerical coning model for an oil/water system. The authors consider constant-rate production followed by a buildup period and assume that the top, bottom, and outer boundaries of the reservoir are sealed. First, they consider the case where the producing interval is equal to the total formation thickness. Second, they discuss the effect of partial penetration. In both cases, they show that average pressure can be estimated by the Matthews-Brons-Hazebroek method and consider the computation of the skin factor. They also show that a reservoir limit test can estimate reservoir PV only if the total mobility adjacent to the wellbore does not vary with time.
Nonlinear explicit transient finite element analysis on the Intel Delta
Energy Technology Data Exchange (ETDEWEB)
Plaskacz, E.J. [Argonne National Lab., IL (United States); Ramirez, M.R.; Gupta, S. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering
1993-03-01
Many large scale finite element problems are intractable on current generation production supercomputers. High-performance computer architectures offer effective avenues to bridge the gap between computational needs and the power of computational hardware. The biggest challenge lies in the substitution of the key algorithms in an application program with redesigned algorithms which exploit the new architectures and use better or more appropriate numerical techniques. A methodology for implementing nonlinear finite element analysis on a homogeneous distributed processing network is discussed. The method can also be extended to heterogeneous networks comprised of different machine architectures provided that they have a mutual communication interface. This unique feature has greatly facilitated the port of the code to the 8-node Intel Touchstone Gamma and then the 512-node Intel Touchstone Delta. The domain is decomposed serially in a preprocessor. Separate input files are written for each subdomain. These files are read in by local copies of the program executable operating in parallel. Communication between processors is addressed utilizing asynchronous and synchronous message passing. The basic kernel of message passing is the internal force exchange which is analogous to the computed interactions between sections of physical bodies in static stress analysis. Benchmarks for the Intel Delta are presented. Performance exceeding 1 gigaflop was attained. Results for two large-scale finite element meshes are presented.
Nonlinear explicit transient finite element analysis on the Intel Delta
Energy Technology Data Exchange (ETDEWEB)
Plaskacz, E.J. (Argonne National Lab., IL (United States)); Ramirez, M.R.; Gupta, S. (Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Civil Engineering)
1993-01-01
Many large scale finite element problems are intractable on current generation production supercomputers. High-performance computer architectures offer effective avenues to bridge the gap between computational needs and the power of computational hardware. The biggest challenge lies in the substitution of the key algorithms in an application program with redesigned algorithms which exploit the new architectures and use better or more appropriate numerical techniques. A methodology for implementing nonlinear finite element analysis on a homogeneous distributed processing network is discussed. The method can also be extended to heterogeneous networks comprised of different machine architectures provided that they have a mutual communication interface. This unique feature has greatly facilitated the port of the code to the 8-node Intel Touchstone Gamma and then the 512-node Intel Touchstone Delta. The domain is decomposed serially in a preprocessor. Separate input files are written for each subdomain. These files are read in by local copies of the program executable operating in parallel. Communication between processors is addressed utilizing asynchronous and synchronous message passing. The basic kernel of message passing is the internal force exchange which is analogous to the computed interactions between sections of physical bodies in static stress analysis. Benchmarks for the Intel Delta are presented. Performance exceeding 1 gigaflop was attained. Results for two large-scale finite element meshes are presented.
Analysis Method of Transient Temperature Field for Fuel Tank of High-Altitude Large UAV
Institute of Scientific and Technical Information of China (English)
Qing Ai; Liang Chen; Xiaojing Xu; Shiyu Liu; Zhenwen Hu; Xinlin Xia
2016-01-01
Based on the analysis of factors affecting transient temperature field of aircraft fuel tank and coupled heat transfer mechanism, a mathematical model of transient coupled heat transfer, including the dynamic change of fuel quality, the internal heat transfer, the external aerodynamic convection and the radiation heat transfer, is established. Taking the aerodynamic convection and radiation heat transfer outside the tank as the third kinds of thermal boundary conditions for the thermal analysis of the fuel tank, calculation of internal and external coupling heat of fuel tank is decoupled. Thermal network method combined with hierarchical dynamic grid is used to deal with the fuel consumption, and carry on the heat transfer analysis of the fuel tank. The numerical method for the transient temperature field of aircraft fuel tank is established. Through the simulation calculation, the transient temperature distribution of the fuel tank under different flight conditions is obtained, and the influence of the fuel mass and the external thermal environment on the temperature field is analyzed.
Greensmith, David J
2014-01-01
Here I present an Excel based program for the analysis of intracellular Ca transients recorded using fluorescent indicators. The program can perform all the necessary steps which convert recorded raw voltage changes into meaningful physiological information. The program performs two fundamental processes. (1) It can prepare the raw signal by several methods. (2) It can then be used to analyze the prepared data to provide information such as absolute intracellular Ca levels. Also, the rates of change of Ca can be measured using multiple, simultaneous regression analysis. I demonstrate that this program performs equally well as commercially available software, but has numerous advantages, namely creating a simplified, self-contained analysis workflow.
Pressure transient analysis methods for bounded naturally fractured reservoirs
Energy Technology Data Exchange (ETDEWEB)
Chen, C-C; Raghavan, R.; Reynolds, A.C.; Serra, K.
1985-06-01
New methods for analyzing drawdown and buildup pressure data obtained at a well located in an infinite, naturally fractured reservoir were presented recently. In this work, the analysis of both drawdown and buildup data in a bounded, naturally fractured reservoir is considered. For the bounded case, the authors show that five possible flow regimes may be exhibited by drawdown data. They delineate the conditions under which each of these five flow regimes exists and the information that can be obtained from each possible combination of flow regimes. Conditions under which semilog methods can be used to analyze buildup data are discussed for the bounded fractured reservoir case. New Matthews-Brons-Hazebroek (MBH) functions for computing the average reservoir pressure from buildup data are presented.
Hayashi, Shimpei; Wakasa, Yuhya; Ozawa, Kenjirou; Takaiwa, Fumio
2016-06-01
In some eukaryotes, endoplasmic reticulum (ER) stress induces regulated inositol-requiring enzyme 1 (IRE1)-dependent decay (RIDD) of mRNAs. Recently, the expression levels of the mRNAs encoding some secretory proteins were reported to be downregulated by RIDD in the vegetative tissues of plants. However, the characteristics of plant RIDD have been insufficiently investigated due to difficulty of in planta analyses. Here, the RIDD susceptibilities of various mRNAs that are difficult to analyze in planta were examined using transient expression analyses of rice protoplasts. In this system, the mRNAs encoding three rice seed storage proteins (SSPs) - namely α-globulin, 16-kDa prolamin and 10-kDa prolamin - were downregulated in response to ER stress. The rapid ER stress-induced degradation of these mRNAs was repressed in cells in which the ribonuclease activity of IRE1 was specifically abolished by genome editing, suggesting that the mRNAs encoding certain SSPs are strong targets of RIDD. Furthermore, we investigated whether these RIDD targets are substrates of the IRE1 ribonuclease using a recombinant IRE1 protein, and identified candidate IRE1-mediated cleavage sites. Overall, the results demonstrate the existence of a post-transcriptional mechanism of regulation of SSPs, and illustrate the basic and multifaceted characteristics of RIDD in higher plants.
Energy Technology Data Exchange (ETDEWEB)
Karaagac, U.; Saad, H.; Mahseredjian, J. [Ecole Polytechnique de Montreal, Montreal, QC (Canada); Jensen, S.; Cai, L. [REpower Systems AG, Hamburg (Germany)
2012-07-01
The large number of switching elements in the modular multilevel converter (MMC) is a challenging problem for modeling the MMC-HVDC systems in electromagnetic transient type (EMT-type) programs. The modeling complexity increases even further when MMC-HVDC systems are used to integrate offshore wind farms (OWFs) with power electronics based wind energy converters, such as doubly-fed induction generators (DFIGs). This paper compares the computational performances of various combinations of MMC-HVDC and OWF models. Practical onshore ac fault scenarios are simulated for an OWF composed of DFIG type wind turbines and connected to a practical ac grid through a point-to-point MMC-HVDC system. (orig.)
Pressure transient analysis for long homogeneous reservoirs using TDS technique
Energy Technology Data Exchange (ETDEWEB)
Escobar, Freddy Humberto [Universidad Surcolombiana, Av. Pastrana - Cra. 1, Neiva, Huila (Colombia); Hernandez, Yuly Andrea [Hocol S.A., Cra. 7 No 114-43, Floor 16, Bogota (Colombia); Hernandez, Claudia Marcela [Weatherford, Cra. 7 No 81-90, Neiva, Huila (Colombia)
2007-08-15
A significant number of well pressure tests are conducted in long, narrow reservoirs with close and open extreme boundaries. It is desirable not only to appropriately identify these types of systems but also to develop an adequate and practical interpretation technique to determine their parameters and size, when possible. An accurate understanding of how the reservoir produces and the magnitude of producible reserves can lead to competent decisions and adequate reservoir management. So far, studies found for identification and determination of parameters for such systems are conducted by conventional techniques (semilog analysis) and semilog and log-log type-curve matching of pressure versus time. Type-curve matching is basically a trial-and-error procedure which may provide inaccurate results. Besides, a limitation in the number of type curves plays a negative role. In this paper, a detailed analysis of pressure derivative behavior for a vertical well in linear reservoirs with open and closed extreme boundaries is presented for the case of constant rate production. We studied independently each flow regime, especially the linear flow regime since it is the most characteristic 'fingerprint' of these systems. We found that when the well is located at one of the extremes of the reservoir, a single linear flow regime develops once radial flow and/or wellbore storage effects have ended. When the well is located at a given distance from both extreme boundaries, the pressure derivative permits the identification of two linear flows toward the well and it has been called that 'dual-linear flow regime'. This is characterized by an increment of the intercept of the 1/2-slope line from {pi}{sup 0.5} to {pi} with a consequent transition between these two straight lines. The identification of intersection points, lines, and characteristic slopes allows us to develop an interpretation technique without employing type-curve matching. This technique uses
Energy Technology Data Exchange (ETDEWEB)
Reventos, F.; Baptista, J.S.; Navas, A.P.; Moreno, P. [Asociacion Nuclear Asco, Barcelona (Spain)
1993-12-01
The Asociacion Nuclear Asco has prepared a model of Asco NPP using RELAP5/MOD2. This model, which include thermalhydraulics, kinetics and protection and controls, has been qualified in previous calculations of several actual plant transients. One of the transients of the qualification process is a ``Pressurizer spray valve faulty opening`` presented in this report. It consists in a primary coolant depressurization that causes the reactor trip by overtemperature and later on the actuation of the safety injection. The results are in close agreement with plant data.
Fine analysis on advanced detection of transient electromagnetic method
Institute of Scientific and Technical Information of China (English)
Wang Bo; Liu Shengdong; Yang Zhen; Wang Zhijun; Huang Lanying
2012-01-01
Fault fracture zones and water-bearing bodies in front of the driving head are the main disasters in mine laneways,thus it is important to perform their advanced detection and prediction in advance in order to provide reliable technical support for the excavation.Based on the electromagnetic induction theory,we analyzed the characteristics of primary and secondary fields with a positive and negative wave form of current,proposed the fine processing of the advanced detection with variation rate of apparent resistivity and introduced in detail the computational formulae and procedures.The result of physical simulation experiments illustrate that the tectonic interface of modules can be judged by first-order rate of apparent resistivity with a boundary error of 5％,and the position of water body determined by the fine analysis method agrees well with the result of borehole drilling.This shows that in terms of distinguishing structure and aqueous anomalies,the first-order rate of apparent resistivity is more sensitive than the secondorder rate of apparent resistivity.However,some remaining problems are suggested for future solutions.
Energy Technology Data Exchange (ETDEWEB)
Chien, T.H.; Domanus, H.M.; Sha, W.T.
1993-02-01
The COMMIX-PPC computer pregrain is an extended and improved version of earlier COMMIX codes and is specifically designed for evaluating the thermal performance of power plant condensers. The COMMIX codes are general-purpose computer programs for the analysis of fluid flow and heat transfer in complex Industrial systems. In COMMIX-PPC, two major features have been added to previously published COMMIX codes. One feature is the incorporation of one-dimensional equations of conservation of mass, momentum, and energy on the tube stile and the proper accounting for the thermal interaction between shell and tube side through the porous-medium approach. The other added feature is the extension of the three-dimensional conservation equations for shell-side flow to treat the flow of a multicomponent medium. COMMIX-PPC is designed to perform steady-state and transient. Three-dimensional analysis of fluid flow with heat transfer tn a power plant condenser. However, the code is designed in a generalized fashion so that, with some modification, it can be used to analyze processes in any heat exchanger or other single-phase engineering applications. Volume I (Equations and Numerics) of this report describes in detail the basic equations, formulation, solution procedures, and models for a phenomena. Volume II (User`s Guide and Manual) contains the input instruction, flow charts, sample problems, and descriptions of available options and boundary conditions.
Energy Technology Data Exchange (ETDEWEB)
Chien, T.H.; Domanus, H.M.; Sha, W.T.
1993-02-01
The COMMIX-PPC computer program is an extended and improved version of earlier COMMIX codes and is specifically designed for evaluating the thermal performance of power plant condensers. The COMMIX codes are general-purpose computer programs for the analysis of fluid flow and heat transfer in complex industrial systems. In COMMIX-PPC, two major features have been added to previously published COMMIX codes. One feature is the incorporation of one-dimensional conservation of mass. momentum, and energy equations on the tube side, and the proper accounting for the thermal interaction between shell and tube side through the porous medium approach. The other added feature is the extension of the three-dimensional conservation equations for shell-side flow to treat the flow of a multicomponent medium. COMMIX-PPC is designed to perform steady-state and transient three-dimensional analysis of fluid flow with heat transfer in a power plant condenser. However, the code is designed in a generalized fashion so that, with some modification. it can be used to analyze processes in any heat exchanger or other single-phase engineering applications.
Modeling and analysis of single-event transients in charge pumps
Institute of Scientific and Technical Information of China (English)
Zhao Zhenyu; Li Junfeng; Zhang Minxuan; Li Shaoqing
2009-01-01
It has been shown that charge pumps (CPs) dominate single-event transient (SET) responses of phaselocked loops (PLLs). Using a pulse to represent a single event hit on CPs, the SET analysis model is established and the characteristics of SET generation and propagation in PLLs are revealed. An analysis of single event transients in PLLs demonstrates that the settling time of the voltage-controlled oscillators (VCOs) control voltage after a single event strike is strongly dependent on the peak control voltage deviation, the SET pulse width, and the settling time constant. And the peak control voltage disturbance decreases with the SET strength or the filter resistance. Furthermore, the analysis in the proposed PLL model is confirmed by simulation results using MATLAB and HSPICE,respectively.
Energy Technology Data Exchange (ETDEWEB)
Liao, L.Y.; Guey, C.N.; Chen, Y.B.; Lee, C.H.
1980-06-01
An analysis has been made with RELAP 4/MOD5 to simulate the system behavior of loss of feedwater transient with safety/relief valve stuck open in Chin Shan BWR. The initial conditions have been established with 105% rated power and 105% flow rate. System variables such as normalized power, steam dome pressure, core inlet flow rate, fuel cladding temperatures, separator mixture level, downcomer mixture level, and core inlet enthalpy have been calculated. A comparison has also been made between the results obtained and those documented in FSAR. It is observed that the general trends of system parameters in both cases are similar, differing slightly only in the timing of the sequence of events postulated to occur. The possibility of idling of ECCS as a result of pool swelling is ruled out. Core uncovery is not observed. In conclusion, the accident analyzed can be accommodated by the design incorporated in the Chin Shan Plant.
Numerical analysis of transient pressure variation in the condenser of a nuclear power station
Energy Technology Data Exchange (ETDEWEB)
Wang, Xinjun; Zhou, Zijie; Song, Zhao [Xi' an Jiaotong University, Xi' an (China); Lu, Qiankui; Li, Jiafu [Dong Fang Turbine Co., Ltd, Deyang (China)
2016-02-15
To research the characteristics of the transient variation of pressure in a nuclear power station condenser under accident condition, a mathematical model was established which simulated the cycling cooling water, heat transfer and pressure in the condenser. The calculation program of transient variation characteristics was established in Fortran language. The pump's parameter, cooling line's organization, check valve's feature and the parameter of siphonic water-collecting well are involved in the cooling water flow's mathematical model. The initial conditions of control volume are determined by the steady state of the condenser. The transient characteristics of a 1000 MW nuclear power station's condenser and cooling water system were examined. The results show that at the condition of plant-power suspension of pump, the cooling water flow rate decreases rapidly and refluxes, then fluctuates to 0. The variation of heat transfer coefficient in the condenser has three stages: at start it decreases sharply, then increases and decreases, and keeps constant in the end. Under three conditions (design, water and summer), the condenser pressure goes up in fluctuation. The time intervals between condenser's pressure signals under three conditions are about 26.4 s, which can fulfill the requirement for safe operation of nuclear power station.
Sorek, Nadav; Poraty, Limor; Sternberg, Hasana; Buriakovsky, Ella; Bar, Einat; Lewinsohn, Efraim; Yalovsky, Shaul
2017-09-11
ROPs or RACs are plant Rho-related GTPases implicated in regulation of multitude of signaling pathways that function at the plasma membrane via posttranslational lipid modifications. The relations between ROP activation status and their membrane localization has not been established. Here, we show that endogenous ROPs, as well as a transgenic His6:GFP:AtROP6 fusion protein, were partitioned between Triton X-100 soluble and insoluble membranes. In contrast, the His6:GFP:Atrop6(CA) activated mutant accumulated exclusively in detergent resistant membranes. GDP induced accumulation of ROPs in Triton-soluble membranes, whereas GTPγS induced accumulation of ROPs in detergent-resistant membranes. Recombinant wild type and constitutively active AtROP6 were purified from Arabidopsis plants and in turn their lipids were cleaved and analyzed by gas chromatography coupled mass spectrometry. In Triton-soluble membranes, the wild type AtROP6 was only prenylated, primarily by geranylgeranyl. The activated AtROP6 that accumulated in detergent resistant membranes was modified by prenyl and acyl lipids, identified to be palmitic and stearic acids. Consistently, activated His6:GFP:Atrop6(CA)mS(156), in which C156 was mutated into serine, accumulated in Triton-soluble membranes. These findings show that upon GTP binding and activation, AtROP6 and possibly other ROPs are transiently S-acylated inducing their partitioning into detergent resistant membranes. Copyright © 2017 American Society for Microbiology.
ANALYSIS OF FIRST TRANSIENT PRESSURE OSCILLATION FOR LEAK DETECTION IN A SINGLE PIPELINE
Institute of Scientific and Technical Information of China (English)
GUO Xin-lei; YANG Kai-lin; LI Fu-tian; WANG Tao; FU hui
2012-01-01
The leak detection is of great importance in the reliable operation and management of a pipeline system.Recently,attention is shifted to the use of the time domain or frequency domain methods based on the transient analysis.These methods sometimes require accurate pressure signals obtained during the transient period or by creating ideal conditions in testing.This paper proposes a method that does not require transient simulations over the whole or an extended period of time,but uses the first transient pressure oscillation to detect leaks.The method considers the propagation of the pressure oscillation wave created from a tast valve closure and the reflected damp wave from the leak.A leak in the pipe gives rise to reflected waves which in turn create discontinuities in the observed signal at the measurement section.The timing of the reflected damp wave and the magnitude represent the location and the size of the leak,respectively.An analytical expression is derived based on the Method Of Characteristic (MOC) for the relationship between the leakage and the reflected magnitude.The leak detection procedure based on the method is also given.Then the reliability of the method is tested on numerically simulated pressure signals and experimental pressure signals with calibrated leak parameters,and the results indicate a successful application and the promising features of the method.
Pressure Transient Analysis of Multi-Fractured Horizontal Well in Tight Gas Reservoirs
Directory of Open Access Journals (Sweden)
Zhao Ermeng
2016-01-01
Full Text Available Multi-fractured horizontal well is applied in tight gas reservoirs due to the low permeability. A new pressure transient model of multi-fractured horizontal well based on discrete-fracture model in which the hydraulic fractures are discretized as 2D entities is built in this paper, The model is divided into hydraulic fracture region and formation region. The model can be solved using the Galerkin finite element method, then the pressure transient type curves are plotted by computer programming. The results show that there are five different flow regimes observed in type curves including early linear flow, early radial flow, elliptical flow, later pseudo-radial flow and boundary response regime. A sensitivity analysis is conducted to study impacts of hydraulic fracture number, hydraulic fracture half-length, hydraulic fracture spacing, and hydraulic fracture conductivity on pressure transient type curves. The new model and obtained results in this paper not only enrich the well testing models, but also play a guiding role in analyzing pressure transient response of multi-fractured horizontal well in tight gas reservoirs.
Galloping comparative analysis for transient main cables of suspension bridge during construction
Li, Shengli; Peng, Gang; Zhang, Haiting; Chen, Huai
2011-04-01
The cross-sectional shapes of two construction projects for the transient main cables are non-circular cross-sections during construction of the long-span suspension bridge, so the transient main cables can experience galloping instabilities. The galloping coefficients of the several representative cases of two construction projects for the transient main cables without wind-resistant measures for the long-span suspension bridge were investigated for the first time by means of the CFD method, referring to an erecting suspension bridge. Results show that for the project 1, at the early stages of the main cables construction, the galloping instabilities can occur, but at the later stages of that, the galloping instabilities cannot occur. For the project 2, there exists a lot of wind attack angles whose galloping coefficients are less than 0 at the whole construction stages. From the perspective for galloping instability the project 1 is better 2.Through the analysis and comparison the galloping performance of two kinds of construction projects for the transient main cables, the advantage and disadvantage for two construction projects is explained theoretically from the perspective for whether can result in the galloping instability.
Marion, Jessica; Bach, Lien; Bellec, Yannick; Meyer, Christian; Gissot, Lionel; Faure, Jean-Denis
2008-10-01
The functional genomics approach requires systematic analysis of protein subcellular distribution and interaction networks, preferably by optimizing experimental simplicity and physiological significance. Here, we present an efficient in planta transient transformation system that allows single or multiple expression of constructs containing various fluorescent protein tags in Arabidopsis cotyledons. The optimized protocol is based on vacuum infiltration of agrobacteria directly into young Arabidopsis seedlings. We demonstrate that Arabidopsis epidermal cells show a subcellular distribution of reference markers similar to that in tobacco epidermal cells, and can be used for co-localization or bi-molecular fluorescent complementation studies. We then used this new system to investigate the subcellular distribution of enzymes involved in sphingolipid metabolism. In contrast to transformation systems using tobacco epidermal cells or cultured Arabidopsis cells, our system provides the opportunity to take advantage of the extensive collections of mutant and transgenic lines available in Arabidopsis. The fact that this assay uses conventional binary vectors and a conventional Agrobacterium strain, and is compatible with a large variety of fluorescent tags, makes it a versatile tool for construct screening and characterization before stable transformation. Transient expression in Arabidopsis seedlings is thus a fast and simple method that requires minimum handling and potentially allows medium- to high-throughput analyses of fusion proteins harboring fluorescent tags in a whole-plant cellular context.
Finite element methodology for transient conduction/forced-convection thermal analysis
Thornton, E. A.; Wieting, A. R.
1979-01-01
Finite element methodology for steady state thermal analysis of convectively cooled structures has been extended for transient analysis. The finite elements are based on representing the fluid passages by fluid bulk-temperature nodes and fluid-solid interface nodes. The formulation of the finite element equations for a typical flow passage is based on the weighted residual method with upwind weighting functions. Computer implementation of the convective finite element methodology using explicit and implicit time integration algorithms is described. Accuracy and efficiency of the methodology is evaluated by comparisons with analytical solutions and finite-difference lumped-parameter analyses. The comparative analyses demonstrate that finite element conduction/conduction methodology may be used to predict transient temperatures with an accuracy equal or superior to the lumped-parameter finite-difference method.
Directory of Open Access Journals (Sweden)
KRISHNA KUMARI.T
2013-04-01
Full Text Available Wind energy plays a prominent role in the generation of power from renewable sources. Generation by permanent magnet synchronous generator (PMSG is recently been popular. But the major concern in using this generator is that the voltage and the power generated are variable due to the intermittent nature of wind energy. Because of the wide use of PMSG the study of the transient stability analysis is very important. In this paper the performance study of PMSG is done by using suitable control strategies to develop a constant voltage and power. The transient stability analysis is also carried out by simulating both the symmetrical and the unsymmetrical faults as network disturbances. This is demonstrated using MATLAB simulations.
Xiaoyong, Bai; Yingbo, He; Chengjun, Chen
2010-06-01
In order to make it easier to extend an finite element software framework with contact implementation for transient solid dynamic analysis, we have designed a general-purposed framework-oriented parallel contact class in this article. A parallel contact computation algorithm model has been generated based on contact schemes reported on last two decades. The class is integrated to an open source platform easily without affecting the rest code of the platform.
Han, Samuel S.; Schafer, Charles F.
1988-01-01
A numerical analysis of transient heat and solute transport across a rectangular cavity with combined horizontal temperature and concentration gradients is performed by a numerical method based on the SIMPLE. Numerical results show that the average Nusselt and Sherwood numbers both decrease markedly when the solutal and thermal buoyancy forces act in the opposite directions. When the solutal and thermal buoyancy forces act in the same directions, however, the average Sherwood number increases significantly and yet the average Nusselt number decreases slightly.
Analysis of transient fission gas behaviour in oxide fuel using BISON and TRANSURANUS
Barani, T.; Bruschi, E.; Pizzocri, D.; Pastore, G.; Van Uffelen, P.; Williamson, R. L.; Luzzi, L.
2017-04-01
The modelling of fission gas behaviour is a crucial aspect of nuclear fuel performance analysis in view of the related effects on the thermo-mechanical performance of the fuel rod, which can be particularly significant during transients. In particular, experimental observations indicate that substantial fission gas release (FGR) can occur on a small time scale during transients (burst release). To accurately reproduce the rapid kinetics of the burst release process in fuel performance calculations, a model that accounts for non-diffusional mechanisms such as fuel micro-cracking is needed. In this work, we present and assess a model for transient fission gas behaviour in oxide fuel, which is applied as an extension of conventional diffusion-based models to introduce the burst release effect. The concept and governing equations of the model are presented, and the sensitivity of results to the newly introduced parameters is evaluated through an analytic sensitivity analysis. The model is assessed for application to integral fuel rod analysis by implementation in two structurally different fuel performance codes: BISON (multi-dimensional finite element code) and TRANSURANUS (1.5D code). Model assessment is based on the analysis of 19 light water reactor fuel rod irradiation experiments from the OECD/NEA IFPE (International Fuel Performance Experiments) database, all of which are simulated with both codes. The results point out an improvement in both the quantitative predictions of integral fuel rod FGR and the qualitative representation of the FGR kinetics with the transient model relative to the canonical, purely diffusion-based models of the codes. The overall quantitative improvement of the integral FGR predictions in the two codes is comparable. Moreover, calculated radial profiles of xenon concentration after irradiation are investigated and compared to experimental data, illustrating the underlying representation of the physical mechanisms of burst release.
An Efficient Topology-Based Algorithm for Transient Analysis of Power Grid
Yang, Lan
2015-08-10
In the design flow of integrated circuits, chip-level verification is an important step that sanity checks the performance is as expected. Power grid verification is one of the most expensive and time-consuming steps of chip-level verification, due to its extremely large size. Efficient power grid analysis technology is highly demanded as it saves computing resources and enables faster iteration. In this paper, a topology-base power grid transient analysis algorithm is proposed. Nodal analysis is adopted to analyze the topology which is mathematically equivalent to iteratively solving a positive semi-definite linear equation. The convergence of the method is proved.
Nonlocal Elasticity Theory for Transient Analysis of Higher-Order Shear Deformable Nanoscale Plates
Directory of Open Access Journals (Sweden)
Woo-Young Jung
2014-01-01
Full Text Available The small scale effect on the transient analysis of nanoscale plates is studied. The elastic theory of the nano-scale plate is reformulated using Eringen’s nonlocal differential constitutive relations and higher-order shear deformation theory (HSDT. The equations of motion of the nonlocal theories are derived for the nano-scale plates. The Eringen’s nonlocal elasticity of Eringen has ability to capture the small scale effects and the higher-order shear deformation theory has ability to capture the quadratic variation of shear strain and consequently shear stress through the plate thickness. The solutions of transient dynamic analysis of nano-scale plate are presented using these theories to illustrate the effect of nonlocal theory on dynamic response of the nano-scale plates. On the basis of those numerical results, the relations between nonlocal and local theory are investigated and discussed, as are the nonlocal parameter, aspect ratio, side-to-thickness ratio, nano-scale plate size, and time step effects on the dynamic response. In order to validate the present solutions, the reference solutions are employed and examined. The results of nano-scale plates using the nonlocal theory can be used as a benchmark test for the transient analysis.
De Petrocellis, Luciano; Vellani, Vittorio; Schiano-Moriello, Aniello; Marini, Pietro; Magherini, Pier Cosimo; Orlando, Pierangelo; Di Marzo, Vincenzo
2008-06-01
The plant cannabinoids (phytocannabinoids), cannabidiol (CBD), and Delta(9)-tetrahydrocannabinol (THC) were previously shown to activate transient receptor potential channels of both vanilloid type 1 (TRPV1) and ankyrin type 1 (TRPA1), respectively. Furthermore, the endocannabinoid anandamide is known to activate TRPV1 and was recently found to antagonize the menthol- and icilin-sensitive transient receptor potential channels of melastatin type 8 (TRPM8). In this study, we investigated the effects of six phytocannabinoids [i.e., CBD, THC, CBD acid, THC acid, cannabichromene (CBC), and cannabigerol (CBG)] on TRPA1- and TRPM8-mediated increase in intracellular Ca2+ in either HEK-293 cells overexpressing the two channels or rat dorsal root ganglia (DRG) sensory neurons. All of the compounds tested induced TRPA1-mediated Ca2+ elevation in HEK-293 cells with efficacy comparable with that of mustard oil isothiocyanates (MO), the most potent being CBC (EC(50) = 60 nM) and the least potent being CBG and CBD acid (EC(50) = 3.4-12.0 microM). CBC also activated MO-sensitive DRG neurons, although with lower potency (EC(50) = 34.3 microM). Furthermore, although none of the compounds tested activated TRPM8-mediated Ca2+ elevation in HEK-293 cells, they all, with the exception of CBC, antagonized this response when it was induced by either menthol or icilin. CBD, CBG, THC, and THC acid were equipotent (IC(50) = 70-160 nM), whereas CBD acid was the least potent compound (IC(50) = 0.9-1.6 microM). CBG inhibited Ca2+ elevation also in icilin-sensitive DRG neurons with potency (IC(50) = 4.5 microM) similar to that of anandamide (IC(50) = 10 microM). Our findings suggest that phytocannabinoids and cannabis extracts exert some of their pharmacological actions also by interacting with TRPA1 and TRPM8 channels, with potential implications for the treatment of pain and cancer.
Current interruption transients calculation
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,
Directory of Open Access Journals (Sweden)
Jikai Chen
2016-12-01
Full Text Available In a power system, the analysis of transient signals is the theoretical basis of fault diagnosis and transient protection theory. Shannon wavelet entropy (SWE and Shannon wavelet packet entropy (SWPE are powerful mathematics tools for transient signal analysis. Combined with the recent achievements regarding SWE and SWPE, their applications are summarized in feature extraction of transient signals and transient fault recognition. For wavelet aliasing at adjacent scale of wavelet decomposition, the impact of wavelet aliasing is analyzed for feature extraction accuracy of SWE and SWPE, and their differences are compared. Meanwhile, the analyses mentioned are verified by partial discharge (PD feature extraction of power cable. Finally, some new ideas and further researches are proposed in the wavelet entropy mechanism, operation speed and how to overcome wavelet aliasing.
Agrobacterium-mediated transient expression system in banana ...
African Journals Online (AJOL)
STORAGESEVER
2009-09-01
Sep 1, 2009 ... Embrapa Genetic Resources and Biotechnology, PqEB, Final Av. W3 Norte, 70770-900 Brasilia-DF, Brazil. Accepted 20 July ... For gene function analysis, transient assays mediated ..... vector for transforming higher plants.
Lovejoy, Andrew E.; Jegley, Dawn C. (Technical Monitor)
2007-01-01
Structures often comprise smaller substructures that are connected to each other or attached to the ground by a set of finite connections. Under static loading one or more of these connections may exceed allowable limits and be deemed to fail. Of particular interest is the structural response when a connection is severed (failed) while the structure is under static load. A transient failure analysis procedure was developed by which it is possible to examine the dynamic effects that result from introducing a discrete failure while a structure is under static load. The failure is introduced by replacing a connection load history by a time-dependent load set that removes the connection load at the time of failure. The subsequent transient response is examined to determine the importance of the dynamic effects by comparing the structural response with the appropriate allowables. Additionally, this procedure utilizes a standard finite element transient analysis that is readily available in most commercial software, permitting the study of dynamic failures without the need to purchase software specifically for this purpose. The procedure is developed and explained, demonstrated on a simple cantilever box example, and finally demonstrated on a real-world example, the American Airlines Flight 587 (AA587) vertical tail plane (VTP).
Institute of Scientific and Technical Information of China (English)
Basdeo Bhagwat; Ming Chi; Li Su; Haifeng Tang; Guiliang Tang; Yu Xiang
2013-01-01
The utility of artificial microRNAs (amiRNAs) to induce loss of gene function has been reported for many plant species,but expression efficiency of the different amiRNA constructs in different transgenic plants was less predictable.In this study,expressions of amiRNAs through the gene backbone of Arabidopsis miR 168a were examined by both Agrobacterium-mediated transient expression and stable plant genetic transformation.A corresponding trend in expression of amiRNAs by the same amiRNA constructs between the transient and the stable expression systems was observed in the experiments.Plant genetic transformation of the constructs that were highly expressible in amiRNAs in the transient agro-infiltration assays resulted in generation of transgenic lines with high level of amiRNAs.This provides a simple method for rapid and effective selection of amiRNA constructs used for a time-consuming genetic transformation in plants.
Transient Stability Analysis of IEEE 9 Bus System in Power World Simulator x
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Transient Stability Analysis of IEEE 9 Bus System in Power World Simulator Ramandeep Kaur,
2016-01-01
Full Text Available It is widely accepted that transient stability is an important aspect in designing and upgrading electric power system. The objective of this paper was to investigate and understand the stability of power system In this paper, modelling and transient stability analysis of IEEE 9 bus system was performed using POWER WORLD SIMULATOR. The load flow studies were performed to determine pre-fault conditions in the system using Newton-Raphson method. With the help of three-phase balanced fault, the variations in power angle and frequency of the system were studied. Frequency is a reliable indicator if deficiency condition in the power systems exists or not. For three-phase balanced fault, fast fault clearing time was analysed to bring back the system to the stability. Further, comparison between Runga method and Euler method for better results was performed. Hence, impact of load switching on system was also computed so as to bring system to steady state.
Data Analysis of Transient Energy Releases in the LHC Superconducting Dipole Magnets
Calvi, M; Bottura, L; Di Castro, M; Masi, A; Siemko, A
2007-01-01
Premature training quenches are caused by transient energy released within the LHC dipole magnet coils while it is energized. Voltage signals recorded across the magnet coils and on the so-called quench antenna carry information about these disturbances. The transitory events correlated to transient energy released are extracted making use of continuous wavelet transform. Several analyses are performed to understand their relevance to the so called training phenomenon. The statistical distribution of the signals amplitude, the number of events occurring at a given current level, the average frequency content of the events are the main parameters on which the analysis have been focalized. Comparisons among different regions of the magnet, among different quenches in the same magnet and among magnets made by different builders are reported. Conclusions about the efficiency of the raw data treatment and the relevance of the parameters developed with respect to the magnet global behavior are finally given.
Analysis of Transient Phenomena Due to a Direct Lightning Strike on a Wind Energy System
Directory of Open Access Journals (Sweden)
João P. S. Catalão
2012-07-01
Full Text Available This paper is concerned with the protection of wind energy systems against the direct effects of lightning. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded as a serious problem. Nevertheless, very few studies exist yet in Portugal regarding lightning protection of wind energy systems using numerical codes. A new case study is presented in this paper, based on a wind turbine with an interconnecting transformer, for the analysis of transient phenomena due to a direct lightning strike to the blade. Comprehensive simulation results are provided by using models of the Restructured Version of the Electro-Magnetic Transients Program (EMTP, and conclusions are duly drawn.
Comparative analysis of twelve Dothideomycete plant pathogens
Energy Technology Data Exchange (ETDEWEB)
Ohm, Robin; Aerts, Andrea; Salamov, Asaf; Goodwin, Stephen B.; Grigoriev, Igor
2011-03-11
The Dothideomycetes are one of the largest and most diverse groups of fungi. Many are plant pathogens and pose a serious threat to agricultural crops grown for biofuel, food or feed. Most Dothideomycetes have only a single host and related Dothideomycete species can have very diverse host plants. Twelve Dothideomycete genomes have currently been sequenced by the Joint Genome Institute and other sequencing centers. They can be accessed via Mycocosm which has tools for comparative analysis
Accuracy of a class of concurrent algorithms for transient finite element analysis
Ortiz, Michael; Sotelino, Elisa D.; Nour-Omid, Bahram
1988-01-01
The accuracy of a new class of concurrent procedures for transient finite element analysis is examined. A phase error analysis is carried out which shows that wave retardation leading to unacceptable loss of accuracy may occur if a Courant condition based on the dimensions of the subdomains is violated. Numerical tests suggest that this Courant condition is conservative for typical structural applications and may lead to a marked increase in accuracy as the number of subdomains is increased. Theoretical speed-up ratios are derived which suggest that the algorithms under consideration can be expected to exhibit a performance superior to that of globally implicit methods when implemented on parallel machines.
Blade loss transient dynamics analysis, volume 1. Task 2: TETRA 2 theoretical development
Gallardo, Vincente C.; Black, Gerald
1986-01-01
The theoretical development of the forced steady state analysis of the structural dynamic response of a turbine engine having nonlinear connecting elements is discussed. Based on modal synthesis, and the principle of harmonic balance, the governing relations are the compatibility of displacements at the nonlinear connecting elements. There are four displacement compatibility equations at each nonlinear connection, which are solved by iteration for the principle harmonic of the excitation frequency. The resulting computer program, TETRA 2, combines the original TETRA transient analysis (with flexible bladed disk) with the steady state capability. A more versatile nonlinear rub or bearing element which contains a hardening (or softening) spring, with or without deadband, is also incorporated.
Gallardo, V. C.; Gaffney, E. F.; Bach, L. J.; Stallone, M. J.
1981-01-01
An analytical technique was developed to predict the behavior of a rotor system subjected to sudden unbalance. The technique is implemented in the Turbine Engine Transient Rotor Analysis (TETRA) computer program using the component element method. The analysis was particularly aimed toward blade-loss phenomena in gas turbine engines. A dual-rotor, casing, and pylon structure can be modeled by the computer program. Blade tip rubs, Coriolis forces, and mechanical clearances are included. The analytical system was verified by modeling and simulating actual test conditions for a rig test as well as a full-engine, blade-release demonstration.
Csank, Jeffrey T.; Zinnecker, Alicia M.
2014-01-01
The aircraft engine design process seeks to achieve the best overall system-level performance, weight, and cost for a given engine design. This is achieved by a complex process known as systems analysis, where steady-state simulations are used to identify trade-offs that should be balanced to optimize the system. The steady-state simulations and data on which systems analysis relies may not adequately capture the true performance trade-offs that exist during transient operation. Dynamic Systems Analysis provides the capability for assessing these trade-offs at an earlier stage of the engine design process. The concept of dynamic systems analysis and the type of information available from this analysis are presented in this paper. To provide this capability, the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) was developed. This tool aids a user in the design of a power management controller to regulate thrust, and a transient limiter to protect the engine model from surge at a single flight condition (defined by an altitude and Mach number). Results from simulation of the closed-loop system may be used to estimate the dynamic performance of the model. This enables evaluation of the trade-off between performance and operability, or safety, in the engine, which could not be done with steady-state data alone. A design study is presented to compare the dynamic performance of two different engine models integrated with the TTECTrA software.
Rukes, Lothar; Paschereit, Oliver; Oberleithner, Kilian
2016-01-01
Modal linear stability analysis has proven very successful in the analysis of coherent structures of turbulent flows. Formally, it describes the evolution of a disturbance in the limit of infinite time. In this work we apply modal linear stability analysis to a turbulent swirling jet undergoing a control parameter transient. The flow undergoes a transition from a non-vortex breakdown state to a state with a strong recirculation bubble and the associated global mode. High-speed Particle Image Velocimetry (PIV) measurements are the basis for a local linear stability analysis of the temporarily evolving base flow. This analysis reveals that the onset of the global mode is strongly linked to the formation of the internal stagnation point. Several transition scenarios are discussed and the ability of a frequency selection criterion to predict the wavemaker location, frequency and growth rate of the global mode are evaluated. We find excellent agreement between the linear global mode frequency and the experimental ...
D'Amico, S.; Lombardo, C.; Moscato, I.; Polidori, M.; Vella, G.
2015-11-01
In the past few decades a lot of theoretical and experimental researches have been done to understand the physical phenomena characterizing nuclear accidents. In particular, after the Three Miles Island accident, several reactors have been designed to handle successfully LOCA events. This paper presents a comparison between experimental and numerical results obtained for the “2 inch Direct Vessel Injection line break” in SPES-2. This facility is an integral test facility built in Piacenza at the SIET laboratories and simulating the primary circuit, the relevant parts of the secondary circuits and the passive safety systems typical of the AP600 nuclear power plant. The numerical analysis here presented was performed by using TRACE and CATHARE thermal-hydraulic codes with the purpose of evaluating their prediction capability. The main results show that the TRACE model well predicts the overall behaviour of the plant during the transient, in particular it is able to simulate the principal thermal-hydraulic phenomena related to all passive safety systems. The performance of the presented CATHARE noding has suggested some possible improvements of the model.
Zór, Kinga; Mark, Christina; Heiskanen, Arto; Madsen, Claus Krogh; Dufva, Martin; Emnéus, Jenny; Brinch-Pedersen, Henrik; Finnie, Christine
2017-09-01
The barley aleurone layer is an established model system for studying phytohormone signalling, enzyme secretion and programmed cell death during seed germination. Most analyses performed on the aleurone layer are end-point assays based on cell extracts, meaning each sample is only analysed at a single time point. By immobilising barley aleurone layer tissue on polydimethylsiloxane pillars in the lid of a multiwell plate, continuous monitoring of living tissue is enabled using multiple non-destructive assays in parallel. Cell viability and menadione reducing capacity were monitored in the same aleurone layer samples over time, in the presence or absence of plant hormones and other effectors. The system is also amenable to transient gene expression by particle bombardment, with simultaneous monitoring of cell death. In conclusion, the easy to handle and efficient experimental setup developed here enables continuous monitoring of tissue samples, parallelisation of assays and single cell analysis, with potential for time course studies using any plant tissue that can be immobilised, for example leaves or epidermal peels. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Quantitative analysis of protein turnover in plants.
Nelson, Clark J; Li, Lei; Millar, A Harvey
2014-03-01
Proteins are constantly being synthesised and degraded as plant cells age and as plants grow, develop and adapt the proteome. Given that plants develop through a series of events from germination to fruiting and even undertake whole organ senescence, an understanding of protein turnover as a fundamental part of this process in plants is essential. Both synthesis and degradation processes are spatially separated in a cell across its compartmented structure. The majority of protein synthesis occurs in the cytosol, while synthesis of specific components occurs inside plastids and mitochondria. Degradation of proteins occurs in both the cytosol, through the action of the plant proteasome, and in organelles and lytic structures through different protease classes. Tracking the specific synthesis and degradation rate of individual proteins can be undertaken using stable isotope feeding and the ability of peptide MS to track labelled peptide fractions over time. Mathematical modelling can be used to follow the isotope signature of newly synthesised protein as it accumulates and natural abundance proteins as they are lost through degradation. Different technical and biological constraints govern the potential for the use of (13)C, (15)N, (2)H and (18)O for these experiments in complete labelling and partial labelling strategies. Future development of quantitative protein turnover analysis will involve analysis of protein populations in complexes and subcellular compartments, assessing the effect of PTMs and integrating turnover studies into wider system biology study of plants.
Environmental analysis for pipeline gas demonstration plants
Energy Technology Data Exchange (ETDEWEB)
Stinton, L.H.
1978-09-01
The Department of Energy (DOE) has implemented programs for encouraging the development and commercialization of coal-related technologies, which include coal gasification demonstration-scale activities. In support of commercialization activities the Environmental Analysis for Pipeline Gas Demonstration Plants has been prepared as a reference document to be used in evaluating potential environmental and socioeconomic effects from construction and operation of site- and process-specific projects. Effluents and associated impacts are identified for six coal gasification processes at three contrasting settings. In general, impacts from construction of a high-Btu gas demonstration plant are similar to those caused by the construction of any chemical plant of similar size. The operation of a high-Btu gas demonstration plant, however, has several unique aspects that differentiate it from other chemical plants. Offsite development (surface mining) and disposal of large quantities of waste solids constitute important sources of potential impact. In addition, air emissions require monitoring for trace metals, polycyclic aromatic hydrocarbons, phenols, and other emissions. Potential biological impacts from long-term exposure to these emissions are unknown, and additional research and data analysis may be necessary to determine such effects. Possible effects of pollutants on vegetation and human populations are discussed. The occurrence of chemical contaminants in liquid effluents and the bioaccumulation of these contaminants in aquatic organisms may lead to adverse ecological impact. Socioeconomic impacts are similar to those from a chemical plant of equivalent size and are summarized and contrasted for the three surrogate sites.
Error estimation in plant growth analysis
Directory of Open Access Journals (Sweden)
Andrzej Gregorczyk
2014-01-01
Full Text Available The scheme is presented for calculation of errors of dry matter values which occur during approximation of data with growth curves, determined by the analytical method (logistic function and by the numerical method (Richards function. Further formulae are shown, which describe absolute errors of growth characteristics: Growth rate (GR, Relative growth rate (RGR, Unit leaf rate (ULR and Leaf area ratio (LAR. Calculation examples concerning the growth course of oats and maize plants are given. The critical analysis of the estimation of obtained results has been done. The purposefulness of joint application of statistical methods and error calculus in plant growth analysis has been ascertained.
Energy Technology Data Exchange (ETDEWEB)
Ortensi, J.; Brian Boer; Abderrafi M. Ougouag
2010-10-01
A rapid increase of the temperature and the mechanical stress is expected in TRISO coated particle fuel that experiences a fast Total Control Rod Ejection (CRE) transient event. During this event the reactor power in the pebble bed core increases significantly for a short time interval. The power is deposited instantly and locally in the fuel kernel. This could result in a rapid increase of the pressure in the buffer layer of the coated fuel particle and, consequently, in an increase of the coating stresses. These stresses determine the mechanical failure probability of the coatings, which serve as the containment of radioactive fission products in the Pebble Bed Reactor (PBR). A new calculation procedure has been implemented at the Idaho National Laboratory (INL), which analyzes the transient fuel performance behavior of TRISO fuel particles in PBRs. This early capability can easily be extended to prismatic designs, given the availability of neutronic and thermal-fluid solvers. The full-core coupled neutronic and thermal-fluid analysis has been modeled with CYNOD-THERMIX. The temperature fields for the fuel kernel and the particle coatings, as well as the gas pressures in the buffer layer, are calculated with the THETRIS module explicitly during the transient calculation. Results from this module are part of the feedback loop within the neutronic-thermal fluid iterations performed for each time step. The temperature and internal pressure values for each pebble type in each region of the core are then input to the PArticle STress Analysis (PASTA) code, which determines the particle coating stresses and the fraction of failed particles. This paper presents an investigation of a Total Control Rod Ejection (TCRE) incident in the 400 MWth Pebble Bed Modular reactor design using the above described calculation procedure. The transient corresponds to a reactivity insertion of $3 (~2000 pcm) reaching 35 times the nominal power in 0.5 seconds. For each position in the core
Directory of Open Access Journals (Sweden)
Sang Hwan Lee
Full Text Available BACKGROUND: Early discrimination between transient and persistent par-solid ground-glass nodules (PSNs at CT is essential for patient management. The objective of our study was to retrospectively investigate the value of texture analysis in differentiating pulmonary transient and persistent PSNs in addition to clinical and CT features. METHODS: This retrospective study was performed with IRB approval and a waiver of the requirement for patients' informed consent. From January 2007 to October 2009, we identified 77 individuals (39 men and 38 women; mean age, 55 years with 86 PSNs on thin-section chest CT. Thirty-nine PSNs in 31 individuals were transient and 47 PSNs in 46 patients were persistent. The clinical, CT, and texture features of PSNs were evaluated. To investigate the additional value of texture analysis in differentiating transient from persistent PSNs, logistic regression analysis and C-statistics were performed. RESULTS: Between transient and persistent PSNs, there were significant differences in age, gender, smoking history, and eosinophil count among the clinical features. As for thin-section CT features, there were significant differences in lesion size, solid portion size, and lesion multiplicity. In terms of texture features, there were significant differences in mean attenuation, skewness of whole PSN, attenuation ratio of whole PSN to inner solid portion, and 5-, 10-, 25-, 50-percentile CT numbers of whole PSN. Multivariate analysis revealed eosinophilia, lesion size, lesion multiplicity, mean attenuation of whole PSN, skewness of whole PSN, and 5-percentile CT number were significant independent predictors of transient PSNs. (P<0.05 C-statistics revealed that texture analysis incorporating clinical and CT features (AUC, 92.9% showed significantly higher differentiating performance of transient from persistent PSNs compared with the clinical and CT features alone (AUC, 79.0%. (P = 0.004. CONCLUSION: Texture analysis of
Plant stress analysis technology deployment
Energy Technology Data Exchange (ETDEWEB)
Ebadian, M.A.
1998-01-01
Monitoring vegetation is an active area of laser-induced fluorescence imaging (LIFI) research. The Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU) is assisting in the transfer of the LIFI technology to the agricultural private sector through a market survey. The market survey will help identify the key eco-agricultural issues of the nations that could benefit from the use of sensor technologies developed by the Office of Science and Technology (OST). The principal region of interest is the Western Hemisphere, particularly, the rapidly growing countries of Latin America and the Caribbean. The analysis of needs will assure that the focus of present and future research will center on economically important issues facing both hemispheres. The application of the technology will be useful to the agriculture industry for airborne crop analysis as well as in the detection and characterization of contaminated sites by monitoring vegetation. LIFI airborne and close-proximity systems will be evaluated as stand-alone technologies and additions to existing sensor technologies that have been used to monitor crops in the field and in storage.
Limitations of transient power loads on DEMO and analysis of mitigation techniques
Energy Technology Data Exchange (ETDEWEB)
Maviglia, F., E-mail: francesco.maviglia@euro-fusion.org [EUROfusion Consortium, PPPT Department, Boltzmannstr. 2, Garching (Germany); Consorzio CREATE, University Napoli Federico II – DIETI, 80125 Napoli (Italy); Federici, G. [EUROfusion Consortium, PPPT Department, Boltzmannstr. 2, Garching (Germany); Strohmayer, G. [Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Wenninger, R. [EUROfusion Consortium, PPPT Department, Boltzmannstr. 2, Garching (Germany); Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Bachmann, C. [EUROfusion Consortium, PPPT Department, Boltzmannstr. 2, Garching (Germany); Albanese, R. [Consorzio CREATE, University Napoli Federico II – DIETI, 80125 Napoli (Italy); Ambrosino, R. [Consorzio CREATE University Napoli Parthenope, Naples (Italy); Li, M. [Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Loschiavo, V.P. [Consorzio CREATE, University Napoli Federico II – DIETI, 80125 Napoli (Italy); You, J.H. [Max-Planck-Institut fur Plasmaphysik, Boltzmannstr. 2, Garching (Germany); Zani, L. [CEA, IRFM, F-13108 St Paul-Lez-Durance (France)
2016-11-01
Highlights: • A parametric thermo-hydraulic analysis of the candidate DEMO divertor is presented. • The operational space assessment is presented under static and transient heat loads. • Strike points sweeping is analyzed as a divertor power exhaust mitigation technique. • Results are presented on sweeping installed power required, AC losses and thermal fatigue. - Abstract: The present European standard DEMO divertor target technology is based on a water-cooled tungsten mono-block with a copper alloy heat sink. This paper presents the assessment of the operational space of this technology under static and transient heat loads. A transient thermo-hydraulic analysis was performed using the code RACLETTE, which allowed a broad parametric scan of the target geometry and coolant conditions. The limiting factors considered were the coolant critical heat flux (CHF), and the temperature limits of the materials. The second part of the work is devoted to the study of the plasma strike point sweeping as a mitigation technique for the divertor power exhaust. The RACLETTE code was used to evaluate the impact of a large range of sweeping frequencies and amplitudes. A reduced subset of cases, which complied with the constraints, was benchmarked with a 3D FEM model. A reduction of the heat flux to the coolant, up to a factor ∼4, and lower material temperatures were found for an incident heat flux in the range (15–30) MW/m{sup 2}. Finally, preliminary assessments were performed on the installed power required for the sweeping, the AC losses in the superconductors and thermal fatigue analysis. No evident show stoppers were found.
Institute of Scientific and Technical Information of China (English)
Guo Yushun
2001-01-01
A new transient analysis method for the transmission line circuits is presented in this paper. Based on the semidiscretization of the telegraph equations, a discretized time domain companion models for the transmission lines which can be conveniently implemented in a general circuit simulator such as SPICE is derived. The computation required for the model is linear with time, equivalent to the recursive convolution-based method. The formulations for both single and coupled lossy transmission lines are given. Numerical experiments are carried out to demonstrate the validity of the method.
Optimization of High-Resolution Continuous Flow Analysis for Transient Climate Signals in Ice Cores
DEFF Research Database (Denmark)
Bigler, Matthias; Svensson, Anders; Kettner, Ernesto
2011-01-01
Over the past two decades, continuous flow analysis (CFA) systems have been refined and widely used to measure aerosol constituents in polar and alpine ice cores in very high-depth resolution. Here we present a newly designed system consisting of sodium, ammonium, dust particles, and electrolytic...... meltwater conductivity detection modules. The system is optimized for high- resolution determination of transient signals in thin layers of deep polar ice cores. Based on standard measurements and by comparing sections of early Holocene and glacial ice from Greenland, we find that the new system features...
DEFF Research Database (Denmark)
Li, Zhongyu; Zhao, Rende; Xin, Zhen
2016-01-01
The Inrush Transient Current (ITC) in the output of the photovoltaic grid-connected inverters is usually generated when grid voltage sag occurs, which can trigger the protection of the grid-connected inverters, and even destroy the semiconductor switches. Then, the grid-connected inverters...... will thus fail to ride through the voltage sag and even further cause more serious grid faults. This paper analyzes the generation principle of ITC and explores its influence factors, upon which, the suppression approaches are presented. Simulation and experimental results validate the theoretical analysis...
Transient Thermal Testing and Analysis of a Thermally Insulating Structural Sandwich Panel
Blosser, Max L.; Daryabeigi, Kamran; Bird, Richard K.; Knutson, Jeffrey R.
2015-01-01
A core configuration was devised for a thermally insulating structural sandwich panel. Two titanium prototype panels were constructed to illustrate the proposed sandwich panel geometry. The core of one of the titanium panels was filled with Saffil(trademark) alumina fibrous insulation and the panel was tested in a series of transient thermal tests. Finite element analysis was used to predict the thermal response of the panel using one- and two-dimensional models. Excellent agreement was obtained between predicted and measured temperature histories.
Consideration of transient heat conduction in a semi-infinite medium using homotopy analysis method
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
In the current work, transient heat conduction in a semi-infinite medium is considered for its many applications in various heat fields. Hcre, the homotopy analysis method (HAM) is applied to solve this problem and analytical results are compared with those of the exact and integral methods results. The results show that the HAM can give much better approximations than the other approximate methods. Changes in heat fluxes and profiles of temperature are obtained at different times and positions for copper, iron and aluminum.
Three-dimensional Transient Analysis in the Upper Plenum of MONJU with MARS-LMR
Energy Technology Data Exchange (ETDEWEB)
Lee, Kwi-Lim; Jeong, Jae-Ho; Ha, Kwi-Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
The JAEA had provided a detailed geometrical data of the reactor vessel upper plenum, and time-dependent inlet conditions of the flow rate and temperature at the reactor core top surface for the transient analysis. The KAERI(Korea Atomic Energy Research Institute) had studied a numerical analysis of thermal stratification in an upper plenum of the MONJU using the MARS-LMR code. Three-dimensional analysis results have a good agreement with the experimental data and also show a better estimation than that of the one-dimensional analysis. Three-dimensional thermal hydraulic analyses are implemented in MARS-LMR code to validate the thermal-hydraulic models of the MARS-LMR code and identify important phenomena such as buoyancy effect and thermal stratification. The results of a 3-D analysis show a better estimation than that of a 1-D analysis. In the steady-state calculation, the total flow rate through UFHs is larger than that of the LFHs unlike a result of a 1-D calculation due to a dominant radial-flow instead of an over-flow by a geometrical interruption of an axially located fuel handling system. In the transient calculation, the sodium keeps overflowing an inner barrel during a simulation time of 3600 sec in the 3-D analysis. As a result, sodium over UFHs steadily continues to be cooled in the 3-D analysis. However, a calculated temperature at the 9th node near the top of an inner barrel is lower than an experimental data. It is considered to be caused by a modeling of an over-flow region as one dimensional volume, because the overflow region has a multi-dimensional flow.
Geldner, Niko; Dénervaud-Tendon, Valérie; Hyman, Derek L; Mayer, Ulrike; Stierhof, York-Dieter; Chory, Joanne
2009-07-01
Plant membrane compartments and trafficking pathways are highly complex, and are often distinct from those of animals and fungi. Progress has been made in defining trafficking in plants using transient expression systems. However, many processes require a precise understanding of plant membrane trafficking in a developmental context, and in diverse, specialized cell types. These include defense responses to pathogens, regulation of transporter accumulation in plant nutrition or polar auxin transport in development. In all of these cases a central role is played by the endosomal membrane system, which, however, is the most divergent and ill-defined aspect of plant cell compartmentation. We have designed a new vector series, and have generated a large number of stably transformed plants expressing membrane protein fusions to spectrally distinct, fluorescent tags. We selected lines with distinct subcellular localization patterns, and stable, non-toxic expression. We demonstrate the power of this multicolor 'Wave' marker set for rapid, combinatorial analysis of plant cell membrane compartments, both in live-imaging and immunoelectron microscopy. Among other findings, our systematic co-localization analysis revealed that a class of plant Rab1-homologs has a much more extended localization than was previously assumed, and also localizes to trans-Golgi/endosomal compartments. Constructs that can be transformed into any genetic background or species, as well as seeds from transgenic Arabidopsis plants, will be freely available, and will promote rapid progress in diverse areas of plant cell biology.
Energy Technology Data Exchange (ETDEWEB)
Le Corre, J.M.; Adamsson, C.; Alvarez, P., E-mail: lecorrjm@westinghouse.com, E-mail: carl.adamsson@psi.ch, E-mail: alvarep@westinghouse.com [Westinghouse Electric Sweden AB (Sweden)
2011-07-01
A benchmark analysis of the transient BFBT data [1], measured in an 8x8 fuel assembly design under typical BWR transient conditions, was performed using the VIPRE-W/MEFISTO-T code package. This is a continuation of the BFBT steady-state benchmark activities documented in [2] and [3]. All available transient void and pressure drop experimental data were considered and the measurements were compared with the predictions of the VIPRE-W sub-channel analysis code using various modeling approaches, including the EPRI drift flux void correlation. Detailed analyses of the code results were performed and it was demonstrated that the VIPRE-W transient predictions are generally reliable over the tested conditions. Available transient dryout data were also considered and the measurements were compared with the predictions of the VIPRE-W/ MEFISTO-T film flow calculations. The code calculates the transient multi-film flowrate distributions in the BFBT bundle, including the effect of spacer grids on drop deposition enhancement, and the dryout criterion corresponds to the total liquid film disappearance. After calibration of the grid enhancement effect with a very small subset of the steady-state critical power database, the code could predict the time and location of transient dryout with very good accuracy. (author)
Pittman, C. M.
1994-01-01
This program performs a one-dimensional numerical analysis of the transient thermal response of multi-layer insulative systems. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a system and determine the total system mass. This program was developed as a tool for designing thermal protection systems for high-speed aerospace vehicles but could be adapted to many areas of industry involved in thermal insulation systems. In this package, the equations describing the transient thermal response of a system are developed. The governing differential equation for each layer and boundary condition are put in finite-difference form using a Taylor's series expansion. These equations yield an essentially tridiagonal matrix of unknown temperatures. A procedure based on Gauss' elimination method is used to solve the matrix. This program is written in FORTRAN IV for the CDC RUN compiler and has been implemented on a CDC 6000 series machine operating under SCOPE 3.0. This program requires a minimum of 44K (octal) of 60 bit words of memory.
Gardner, Jens Christopher
A transient-absorption spectrometer to study the electric field component of the proton-motive force (PMF) has been developed. Excitation by an actinic light source (655nm) causes absorption changes of pigments in the sample at 520nm on the order of 0.1%. Using a probe light source at 520nm, the change in transmission before and after actinic excitation can be detected and quantified. Because the change in transmission is small, a high signal to noise ratio (SNR) is required. To reduce the effect of optical shot noise and front end electrical noise a high intensity source at 520nm is utilized. However, continuous high intensity light at 520nm over time can cause actinic excitation in the sample, so the 520nm probe is pulsed at high optical intensity and low duty cycle to reduce the net incident flux. The developed system includes 1) a LED driver to drive 1A current pulses through three high power probe LEDs and four high power actinic LEDs, 2) an analog front end which uses a 10mm by 10mm photodiode and a trans-impedance amplifier to detect the pulses, as well as several signal processing stages, 3) a microcontroller to generate the probe timing waveforms, digitize the detected signal, and send the data to a PC, and 4) a LabView computer interface to set input parameters, display the collected data, and save the data to a text file. Experimental verification of system peformance was performed by testing the system with and without a plant sample. The results show that the system works as expected and is capable of measuring the data required to determine the electric field component of the PMF.
Electromagnetic transient analysis and Novell protective relaying techniques for power transformers
Lin, X; Tian, Q; Weng, H
2015-01-01
This book addresses the technical challenges of transformer malfunction analysis as well as protection. One of the current research directions is the malfunction mechanism analysis due to nonlinearity of transformer core and comprehensive countermeasures on improving the performance of transformer differential protection. Here, the authors summarize their research outcomes and present a set of recent research advances in the electromagnetic transient analysis, the application on power transformer protections, and present a more systematic investigation and review in this field. This research area is still progressing, especially with the fast development of Smart Grid. This book is an important addition to the literature and will enhance significant advancement in research. It is a good reference book for researchers in power transformer protection research and a good text book for graduate and undergraduate students in electrical engineering.
Transient analysis of an HTS DC power cable with an HVDC system
Energy Technology Data Exchange (ETDEWEB)
Dinh, Minh-Chau, E-mail: thanchau7787@gmail.com [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yu, In-Keun, E-mail: yuik@cwnu.ac.kr [Department of Electrical Engineering, Changwon National University, 9 Sarim-Dong, Changwon 641-773 (Korea, Republic of); Yang, Byeongmo [Korea Electric Power Research Institute, 105 Munji-Ro, Yuseong-Gu, Daejon 305-760 (Korea, Republic of)
2013-11-15
Highlights: •A model of an HTS DC power cable was developed using real time digital simulator. •The simulations of the HTS DC power cable in connection with an HVDC system were performed. •The transient analysis results of the HTS DC power cable were presented. -- Abstract: The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.
Analysis on conducted coupling of electrical fast transient burst in mines
Institute of Scientific and Technical Information of China (English)
FENG De-wang; LAN Jian-rong
2012-01-01
Under the inflammable or explosive environment,the direct measurement methods by opening up the explosion-proof shell of electrical installations were not adopted.So,it's impossible to have a quantitative analysis on the limit of conducted disturbance for electrical fast transient burst (EFT/B) in such dangerous environments.Transient conducted coupling model,which using EFT/B as its excitation source,can be built based on circuit and electromagnetic field theory.Furthermore,numerical analysis was performed.The results indicate that the capacitive coupling voltage is the same polarity as EFT/B,and is the main disturbance form of conducted coupling in mines.The inductive coupling voltage is reversed polarity with the capacitive coupling voltage,and both peaks appear only in the rising time of EFT/B,which increase with the rising of load resistance.Moreover,the cable coupling voltage on the side of disturbance source is higher than the one on the other side in tunnel.To reduce the common resistance can suppress the resistive coupling disturbance.
Multimechanism-Deformation Parameters of Domal Salts Using Transient Creep Analysis
Energy Technology Data Exchange (ETDEWEB)
MUNSON, DARRELL E
1999-09-01
Use of Gulf Coast salt domes for construction of very large storage caverns by solution mining has grown significantly in the last several decades. In fact, among the largest developers of storage caverns along the Gulf Coast is the Strategic Petroleum Reserve (SPR) which has purchased or constructed 62 crude oil storage caverns in four storage sites (domes). Although SPR and commercial caverns have been operated economically for many years, the caverns still exhibit some relatively poorly understood behaviors, especially involving creep closure volume loss and hanging string damage from salt falls. Since it is possible to postulate that some of these behaviors stem from geomechanical or reformational aspects of the salt, a method of correlating the cavern response to mechanical creep behavior as determined in the laboratory could be of considerable value. Recently, detailed study of the creep response of domal salts has cast some insight into the influence of different salt origins on cavern behavior. The study used a simple graphical analysis of limited non-steady state data to establish an approach or bound to steady state, as an estimate of the steady state behavior of a given salt. This permitted analysis of sparse creep databases for domal salts. It appears that a shortcoming of this steady state analysis method is that it obscures some critical differences of the salt material behavior. In an attempt to overcome the steady state analysis shortcomings, a method was developed based on integration of the Multimechanism-Deformation (M-D) creep constitutive model to obtain fits to the transient response. This integration process permits definition of all the material sensitive parameters of the model, while those parameters that are constants or material insensitive parameters are fixed independently. The transient analysis method has proven more sensitive to differences in the creep characteristics and has provided a way of defining different behaviors within a
Transient Analysis for the Multimechanism-Deformation Parameters of Several Domal Salts
Energy Technology Data Exchange (ETDEWEB)
Munson, Darrell E.
1999-08-16
Use of Gulf Coast salt domes for construction of very large storage caverns by solution mining has grown significantly in the last several decades. In fact, a nationally important Strategic Petroleum Reserve (SPR) storage occurs in large cavern arrays in some of these domes. Although caverns have been operated economically for these many years, these caverns have a range of relatively poorly understood behaviors, involving creep closure fluid loss and damage from salt falls. It is certainly possible to postulate that many of these behaviors stem from geomechanical or deformational aspects of the salt response. As a result, a method of correlating the cavern response to mechanical creep behavior as determined in the laboratory could be of considerable importance. Recently, detailed study of the creep response of domal salts has cast some insight into the influence of different salt origins on cavern behavior. The study used a simple graphical analysis of the limited non-steady state data to give a bound, or an approach to steady state, as an estimate of the steady state behavior of a given domal salt. This permitted the analysis of sparse creep databases for domal salts. It appears that a shortcoming of the steady state analysis was in masking some of the salt material differences. In an attempt to overcome the steady state analysis shortcomings, a method was developed based on the integration of the Multimechanism-Deformation (M-D) creep constitutive model to fit the transient response. This integration process essentially permits definition of the material sensitive parameters of the model, while those parameters that are either constants or material insensitive parameters are fixed independently. The transient analysis method has proven more sensitive to differences in the creep characteristics and has provided a way of defining different behaviors within a given dome. Creep characteristics, as defined by the transient analysis of the creep rate, are related
Improved analysis of transient temperature data from permanent down-hole gauges (PDGs)
Zhang, Yiqun; Zheng, Shiyi; Wang, Qi
2017-08-01
With the installation of permanent down-hole gauges (PDGs) during oil field development, large volumes of high resolution and continuous down-hole information are obtainable. The interpretation of these real-time temperature and pressure data can optimize well performance, provide information about the reservoir and continuously calibrate the reservoir model. Although the dynamic temperature data have been interpreted in practice to predict flow profiling and provide characteristic information of the reservoir, almost all of the approaches rely on established non-isothermal models which depend on thermodynamic parameters. Another problem comes from the temperature transient analysis (TTA), which is underutilized compared with pressure transient analysis (PTA). In this study, several model-independent methods of TTA were performed. The entire set of PDG data consists of many flow events. By utilizing the wavelet transform, the exact points of flow-rate changes can be located. The flow regime changes, for example, from early time linear flow to later time pseudo-radial flow, among every transient period with constant flow-rate. For the early time region (ETR) that is caused by flow-rate change operations, the TTA, along with the PTA can greatly reduce the uncertainties in flow regime diagnosis. Then, the temperature variations during ETR were examined to infer the true reservoir temperature history, and the relationships between the wavelet detailed coefficients and the flow-rate changes were analysed. For the scenarios with constant reservoir-well parameters, the detailed flow-rate history can be generated by calculating the coefficient of relationship in advance. For later times, the flow regime changes to pseudo-radial flow. An analytical solution was introduced to describe the sand-face temperature. The formation parameters, such as permeability and skin factor, were estimated with the previously calculated flow-rate. It is necessary to analyse temperature
steady state and transient analysis of induction motor driving a pump ...
African Journals Online (AJOL)
Dr Obe
The importance of using a digital computer in studying the performance of Induction machine under steady and transient states is presented with computer results which show the transient ... time as against analog-computer, has been realized ...
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.
Preliminary Analysis of the Transient Reactor Test Facility (TREAT) with PROTEUS
Energy Technology Data Exchange (ETDEWEB)
Connaway, H. M. [Argonne National Lab. (ANL), Argonne, IL (United States); Lee, C. H. [Argonne National Lab. (ANL), Argonne, IL (United States)
2015-11-30
The neutron transport code PROTEUS has been used to perform preliminary simulations of the Transient Reactor Test Facility (TREAT). TREAT is an experimental reactor designed for the testing of nuclear fuels and other materials under transient conditions. It operated from 1959 to 1994, when it was placed on non-operational standby. The restart of TREAT to support the U.S. Department of Energy’s resumption of transient testing is currently underway. Both single assembly and assembly-homogenized full core models have been evaluated. Simulations were performed using a historic set of WIMS-ANL-generated cross-sections as well as a new set of Serpent-generated cross-sections. To support this work, further analyses were also performed using additional codes in order to investigate particular aspects of TREAT modeling. DIF3D and the Monte-Carlo codes MCNP and Serpent were utilized in these studies. MCNP and Serpent were used to evaluate the effect of geometry homogenization on the simulation results and to support code-to-code comparisons. New meshes for the PROTEUS simulations were created using the CUBIT toolkit, with additional meshes generated via conversion of selected DIF3D models to support code-to-code verifications. All current analyses have focused on code-to-code verifications, with additional verification and validation studies planned. The analysis of TREAT with PROTEUS-SN is an ongoing project. This report documents the studies that have been performed thus far, and highlights key challenges to address in future work.
Nordic Symposium on Analysis of Electromagnetic Transient Phenomena Using EMTP, part 2
Jokinen, Tapani
The Electromagnetic Transients Program (EMTP) is a computer program used to simulate electromagnetic, electromechanical, and control system transients on multiphase electric power systems. Section headings in this volume include the following: Case Studies for Electromagnetic Transients; Transformers - Section 6 from EMTP Theory Book, Second Edition; What Is Needed In Transformer Representations; and Transformer Inrush Current, Test Case 1.
Transient and Steady-State Analysis of Nonlinear RF and Microwave Circuits
Directory of Open Access Journals (Sweden)
Zhu Lei(Lana
2006-01-01
Full Text Available This paper offers a review of simulation methods currently available for the transient and steady-state analysis of nonlinear RF and microwave circuits. The most general method continues to be the time-marching approach used in Spice, but more recent methods based on multiple time dimensions are particularly effective for RF and microwave circuits. We derive nodal formulations for the most widely used multiple time dimension methods. We put special emphasis on methods for the analysis of oscillators based in the warped multitime partial differential equations (WaMPDE approach. Case studies of a Colpitts oscillator and a voltage controlled Clapp-Gouriet oscillator are presented and discussed. The accuracy of the amplitude and phase of these methods is investigated. It is shown that the exploitation of frequency-domain latency reduces the computational effort.
Transient Stability Analysis of the SeCRETS Experiment in SULTAN
Bottura, L; Marinucci, C
2002-01-01
We present here the results of the analysis of the stability experiment SeCRETS, performed on two Nb3Sn cable-in-conduit conductors with the same amount of total copper stabilizer, but different degree of segregation. The model used for the analysis, including superconducting strands, conductor jacket and helium, is solved with the code GandalfTM. We obtain a qualitative agreement of simulation results and experimental values. The simulation results confirm that in the operation regime explored in the experiment the segregated copper is not effective for stability. The details of the current sharing and the approximation taken for the transient heat transfer are shown to be critical for the interpretation.
A study on the transient piping vibration of power plant. Secondary piping system of Wolsung 1 unit
Energy Technology Data Exchange (ETDEWEB)
Lee, Hyun; Kim, Yeon Whan [Korea Electric Power Corp. (KEPCO), Taejon (Korea, Republic of). Research Center
1996-08-01
In order to maintain a safe operation and availability of generating facilities, qualitative and quantitative assessment of piping vibration was performed vibration sources and damages of piping support was identified on the second piping system of Wolsung nuclear power plant unit 1 .Inspected piping supports and structures in both hot and cold condition .Established evaluation procedures of piping vibration .Performed the static analysis of 2 nd piping system .Established optimal vibration reducing method .The measured vibration level after installing rigid supports and energy absorbing type restraint was reduced about 7 times in velocity unit (author). 24 refs., 95 figs.
Kiedron, K.; Chian, C. T.
1985-01-01
As a check on structure safety aspects, two approaches in seismic analysis for the large 70-m antennas are presented. The first approach, commonly used by civil engineers, utilizes known recommended design response spectra. The second approach, which is the full transient analysis, is versatile and applicable not only to earthquake loading but also to other dynamic forcing functions. The results obtained at the fundamental structural frequency show that the two approaches are in good agreement with each other and both approaches show a safe design. The results also confirm past 64-m antenna seismic studies done by the Caltech Seismology Staff.
Exergoeconomic analysis of a cogeneration plant
Energy Technology Data Exchange (ETDEWEB)
Mert, Mehmet Selcuk [Yalova University, Energy Systems Engineering Department (Turkey)], email: msmert@yalova.edu.tr; Dilmac, Omer Faruk; Ozkan, Semra; Bolat, Esen [Yildiz Technical University Chemical Engineering Department (Turkey)], email: omerfarukdl@yahoo.com, email: ozkans@yildiz.edu.tr, email: ebolat@yildiz.edu.tr
2011-07-01
Cogeneration, or combined heat and power, is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat generally in the form of steam or hot water. By capturing the excess heat, it uses thermal energy that would be wasted in a conventional power plant, provides high energy conversion efficiency, and also reduces emissions. Exergy analysis has been found to be an effective tool for predicting the efficiencies of system components and the total thermodynamic effectiveness of the system, as well as for highlighting possible improvements. By using both exergy concepts and economics, an exergoeconomic analysis is possible which helps designers to find ways to improve the performance of a system in a cost effective way. This study presents the exergoeconomic analysis of a cogeneration plant at Erdemir, Turkey. The mass, energy and exergy balances were done, and the exergoeconomic analysis of the plant, with a 39.5 MW electricity total net power and 20.83 kg/s steam production capacity, was also done.
Exergoeconomic analysis of a nuclear power plant
Moreno, Roman Miguel
Exergoeconomic analysis of a nuclear power plant is a focus of this dissertation. Specifically, the performance of the Palo Verde Nuclear Power Plant in Arizona is examined. The analysis combines thermodynamic second law exergy analysis with economics in order to assign costs to the loss and destruction of exergy. This work was done entirely with an interacting spreadsheets notebook. The procedures are to first determine conventional energy flow, where the thermodynamic stream state points are calculated automatically. Exergy flow is then evaluated along with destruction and losses. The capital cost and fixed investment rate used for the economics do not apply specifically to the Palo Verde Plant. Exergy costing is done next involving the solution of about 90 equations by matrix inversion. Finally, the analysis assigns cost to the exergy destruction and losses in each component. In this work, the cost of electricity (exergy), including capital cost, leaving the generator came to 38,400 /hr. The major exergy destruction occurs in the reactor where fission energy transfer is limited by the maxiμm permissible clad temperature. Exergy destruction costs were: reactor--18,207 hr, the low pressure turbine-2,000 /hr, the condenser--1,700 hr, the steam generator-1,200 $/hr. The inclusion of capital cost and O&M are important in new system design assessments. When investigating operational performance, however, these are sunk costs; only fuel cost needs to be considered. The application of a case study is included based on a real modification instituted at Palo Verde to reduce corrosion steam generator problems; the pressure in the steam generator was reduced from 1072 to 980 psi. Exergy destruction costs increased in the low pressure turbine and in the steam generator, but decreased in the reactor vessel and the condenser. The dissertation demonstrates the procedures and tools required for exergoeconomic analysis whether in the evaluation of a new nuclear reactor system
Compressor Modeling for Transient Analysis of Supercritical CO2 Brayton Cycle by using MARS code
Energy Technology Data Exchange (ETDEWEB)
Park, Joo Hyun; Park, Hyun Sun; Kim, Tae Ho; Kwon, Jin Gyu [POSTECH, Pohang (Korea, Republic of); Bae, Sung Won; Cha, Jae Eun [KAERI, Daejeon (Korea, Republic of)
2016-05-15
In this study, SCIEL (Supercritical CO{sub 2} Integral Experimental Loop) was chosen as a reference loop and the MARS code was as the transient cycle analysis code. As a result, the compressor homologous curve was developed from the SCIEL experimental data and MARS analysis was performed and presented in the paper. The advantages attract SCO{sub 2}BC as a promising next generation power cycles. The high thermal efficiency comes from the operation of compressor near the critical point where the properties of SCO{sub 2}. The approaches to those of liquid phase, leading drastically lower the compression work loss. However, the advantage requires precise and smooth operation of the cycle near the critical point. However, it is one of the key technical challenges. The experimental data was steady state at compressor rotating speed of 25,000 rpm. The time, 3133 second, was starting point of steady state. Numerical solutions were well matched with the experimental data. The mass flow rate from the MARS analysis of approximately 0.7 kg/s was close to the experimental result of 0.9 kg/s. It is expected that the difference come from the measurement error in the experiment. In this study, the compressor model was developed and implemented in MARS to study the transient analysis of SCO{sub 2}BC in SCIEL. We obtained the homologous curves for the SCIEL compressor using experimental data and performed nodalization of the compressor model using MARS code. In conclusions, it was found that numerical solutions from the MARS model were well matched with experimental data.
Directory of Open Access Journals (Sweden)
Andrzej Rusek
2008-01-01
Full Text Available The mathematical model of cylindrical linear induction motor (C-LIM fed via frequency converter is presented in the paper. The model was developed in order to analyze numerically the transient states. Problems concerning dynamics of ac-machines especially linear induction motor are presented in [1 – 7]. Development of C-LIM mathematical model is based on circuit method and analogy to rotary induction motor. The analogy between both: (a stator and rotor windings of rotary induction motor and (b winding of primary part of C-LIM (inductor and closed current circuits in external secondary part of C-LIM (race is taken into consideration. The equations of C-LIM mathematical model are presented as matrix together with equations expressing each vector separately. A computational analysis of selected transient states of C-LIM fed via frequency converter is presented in the paper. Two typical examples of C-LIM operation are considered for the analysis: (a starting the motor at various static loads and various synchronous velocities and (b reverse of the motor at the same operation conditions. Results of simulation are presented as transient responses including transient electromagnetic force, transient linear velocity and transient phase current.
Wavelet-based analysis of transient electromagnetic wave propagation in photonic crystals.
Shifman, Yair; Leviatan, Yehuda
2004-03-01
Photonic crystals and optical bandgap structures, which facilitate high-precision control of electromagnetic-field propagation, are gaining ever-increasing attention in both scientific and commercial applications. One common photonic device is the distributed Bragg reflector (DBR), which exhibits high reflectivity at certain frequencies. Analysis of the transient interaction of an electromagnetic pulse with such a device can be formulated in terms of the time-domain volume integral equation and, in turn, solved numerically with the method of moments. Owing to the frequency-dependent reflectivity of such devices, the extent of field penetration into deep layers of the device will be different depending on the frequency content of the impinging pulse. We show how this phenomenon can be exploited to reduce the number of basis functions needed for the solution. To this end, we use spatiotemporal wavelet basis functions, which possess the multiresolution property in both spatial and temporal domains. To select the dominant functions in the solution, we use an iterative impedance matrix compression (IMC) procedure, which gradually constructs and solves a compressed version of the matrix equation until the desired degree of accuracy has been achieved. Results show that when the electromagnetic pulse is reflected, the transient IMC omits basis functions defined over the last layers of the DBR, as anticipated.
New Methods for Timing Analysis of Transient Events, Applied to Fermi/GBM Magnetar Bursts
Huppenkothen, Daniela; Uttley, Phil; van der Horst, Alexander J; van der Klis, Michiel; Kouveliotou, Chryssa; Gogus, Ersin; Granot, Jonathan; Vaughan, Simon; Finger, Mark H
2013-01-01
In order to discern the physical nature of many gamma-ray sources in the sky, we must look not only in spectral and spatial dimensions, but also understand their temporal variability. However, timing analysis of sources with a highly transient nature, such as magnetar bursts, is difficult: standard Fourier techniques developed for long-term variability generally observed, for example, from AGN often do not apply. Here, we present newly developed timing methods applicable to transient events of all kinds, and show their successful application to magnetar bursts observed with Fermi/GBM. Magnetars are a prime subject for timing studies, thanks to the detection of quasi-periodicities in magnetar Giant Flares and their potential to help shed light on the structure of neutron stars. Using state-of-the art statistical techniques, we search for quasi-periodicities (QPOs) in a sample of bursts from Soft Gamma Repeater SGR J0501+4516 observed with Fermi/GBM and provide upper limits for potential QPO detections. Additio...
Rayleigh-Taylor instability under curved substrates: An optimal transient growth analysis
Balestra, Gioele; Brun, P.-T.; Gallaire, François
2016-12-01
We investigate the stability of thin viscous films coated on the inside of a horizontal cylindrical substrate. In such a case, gravity acts both as a stabilizing force through the progressive drainage of the film and as a destabilizing force prone to form droplets via the Rayleigh-Taylor instability. The drainage solution, derived from lubrication equations, is found asymptotically stable with respect to infinitesimally small perturbations, although in reality, droplets often form. To resolve this paradox, we perform an optimal transient growth analysis for the first-order perturbations of the liquid's interface, generalizing the results of Trinh et al. [Phys. Fluids 26, 051704 (2014), 10.1063/1.4876476]. We find that the system displays a linear transient growth potential that gives rise to two different scenarios depending on the value of the Bond number (prescribing the relative importance of gravity and surface tension forces). At low Bond numbers, the optimal perturbation of the interface does not generate droplets. In contrast, for higher Bond numbers, perturbations on the upper hemicircle yield gains large enough to potentially form droplets. The gain increases exponentially with the Bond number. In particular, depending on the amplitude of the initial perturbation, we find a critical Bond number above which the short-time linear growth is sufficient to trigger the nonlinear effects required to form dripping droplets. We conclude that the transition to droplets detaching from the substrate is noise and perturbation dependent.
Direct Transient Analysis of a Fuze Assembly by Axisymmetric Solid Elements
Dai, C. C.; Yang, J. C. S.; Titus, J.
1985-01-01
A fuze assembly, which consists of three major parts, nose, collar and sleeve, was designed to survive severe transverse impact giving a maximum base acceleration of 20.000 G. It is shown that hoop failure occurred in the collar after the impact. They also showed that by bonding the collar to the nose, the collar was able to survive the same impact. To find out the effectiveness of the bonding quantitatively, axisymmetric solid elements TRAPAX and TRIAAX were used in modelling the fuze and direct transient analysis was performed. The dynamic stresses in selected elements on the bonded and unbonded collars were compared. The peak hoop stresses in the unbonded collar were found to be up to three times higher than those in the bonded collar. The NASTRAN results explained the observed hoop failure in the unbonded collar. In addition, static and eigenvalue runs were performed as checks on the models prior to the transient runs. The use of the MPCAX cards and the existence and contributors of the calculated first several nearly identical natural frequencies are addressed.
Development of an Aeroelastic Modeling Capability for Transient Nozzle Side Load Analysis
Wang, Ten-See; Zhao, Xiang; Zhang, Sijun; Chen, Yen-Sen
2013-01-01
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 coupled aeroelastic modeling capability 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 in the framework of modal analysis. Transient aeroelastic nozzle startup analyses of the Block I Space Shuttle Main Engine at sea level were performed. The computed results from the aeroelastic nozzle modeling are presented.
Institute of Scientific and Technical Information of China (English)
Huang Ren; Qiu Zhiping
2013-01-01
To investigate the transient aeroelastic responses and flutter characteristics of a variable-span wing during the morphing process, a novel first-order state-space aeroelastic model is pro-posed. The time-varying structural model of the morphing wing is established based on the Euler-Bernoulli beam theory with time-dependent boundary conditions. A nondimensionalization method is used to translate the time-dependent boundary conditions to be time-independent. The time-domain aerodynamic forces are calculated by the reduced-order unsteady vortex lattice method. The morphing parameters, i.e., wing span length and morphing speed, are of particular interest for understanding the fundamental aeroelastic behavior of variable-span wings. A test case is proposed and numerical results indicate that the flutter characteristics are sensitive to both of the two morphing parameters. It could be noticed that the aeroelastic characteristics during the wing extracting process are more serious than those during the extending process at the same morphing speed by transient aeroelastic response analysis. In addition, a faster morphing process can get bet-ter aeroelastic performance while the mechanism comlexity will arise.
Institute of Scientific and Technical Information of China (English)
SUN Xian-Jing; DENG Chang-Dong; KANG Wen
2012-01-01
Due to the large cddy currents at the ends of the quadrupole magnets for CSNS/RCS,the magnetic field properties and the heat generation are of great concern.In this paper,we take transient electromagnetic simulation and make use of the eddy current loss from the transient electromagnetic results to perform thermal analysis.Through analysis of the simulated results,the magnetic field dynamic properties of these magnets and a temperature rise are achieved.Finally,the accuracy of the thermal analysis is confirmed by a test of the prototype quadrupole magnet of the RCS.
Chujo, Toshihiro; Kawaguchi, Junichiro
2016-10-01
This study evaluates the transient response of large spinning membrane structures in space - especially spinning solar sails - by two different methods. A flexible sail membrane is easily deformed when a spacecraft changes its attitude, such as when using thrusters, and the control response including membrane vibration must be estimated in advance of operation. In order to estimate the motion of the membrane, numerical simulations using a multi-particle model (MPM) are conducted, where the membrane is modeled with masses, spring, and dampers. Usually, force propagation is calculated directly in this model and the position and velocity of each particle represent the membrane motion, which is referred to as a continuum analysis in this study. This method is useful for the analysis of membrane vibration because it replaces the complex dynamics with simple equations of motion. However, the computational cost is high and the calculations require a considerable amount of time. This study introduces an eigenfunction analysis to solve this problem. In this method, natural vibration modes and natural frequencies for the entire spacecraft are derived and used for dynamics computation, which reduces the computational cost dramatically compared to the conventional continuum analysis. In this study, the transient response of a spinning solar sail is analyzed using both methods, and the advantages and disadvantages are discussed. It is shown that the eigenfunction analysis provides a suitable method for acquiring approximate solutions in a very low computation time.
DEFF Research Database (Denmark)
Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.
2013-01-01
A fast rotating 1500 rpm radial piston digital displacement motor connected to a 350 bar high pressure manifold is simulated by means of transient 3D CFD analysis of a single pressure chamber. The analysis includes dynamic piston and valve movement, influencing the boundaries of the fluid domain....
FETSIM user's manual and example. [D.C. and transient analysis of MOS circuits
1978-01-01
A batch program written in FORTRAN IV which does D.C. and transient analysis of MOS circuits is presented. Circuits employing N-MOS transistors and/or P-MOS transistors in either a bulk technology or an SOS technology, or almost any combination of R-C elements may be analyzed. The program requires as input data the complete circuit topology, device parameters, process parameters, and control parameters. The user can specify initial node conditions and the input pulse format. For example, pulse rise time, fall time, width and time between succeeding pulses are all independently controllable. The program contains a sophisticated mathematical model that can accurately handle either NMOS, P-MOS, Bulk or SOS devices. Sensitivity to process changes is maintained by requiring such process parameters as threshold voltage and doping level as program inputs.
Su, Zhu; Jin, Guoyong; Ye, Tiangui
2016-06-01
The paper presents a unified solution for free and transient vibration analyses of a functionally graded piezoelectric curved beam with general boundary conditions within the framework of Timoshenko beam theory. The formulation is derived by means of the variational principle in conjunction with a modified Fourier series which consists of standard Fourier cosine series and supplemented functions. The mechanical and electrical properties of functionally graded piezoelectric materials (FGPMs) are assumed to vary continuously in the thickness direction and are estimated by Voigt’s rule of mixture. The convergence, accuracy and reliability of the present formulation are demonstrated by comparing the present solutions with those from the literature and finite element analysis. Numerous results for FGPM beams with different boundary conditions, geometrical parameters as well as material distributions are given. Moreover, forced vibration of the FGPM beams subjected to dynamic loads and general boundary conditions are also investigated.
Sensitivity analysis and numerical experiments on transient test of compact heat exchanger surfaces
Institute of Scientific and Technical Information of China (English)
Hesheng REN; Lingjun LAI; Yongzheng CUI
2008-01-01
A single-blow transient testing technique con-sidering the effect of longitudinal heat conduction is sug-gested for determining the average convection heat transfer coefficient of compact heat exchanger surface. By matching the measured outlet fluid temperature vari-ation with similar theoretical curves, the dimensionless longitudinal conduction parameter λ1, the time constant of the inlet fluid temperature τ+, and the number of heat transfer units Ntu can be determined simultaneously using the Levenberg-Marquardt nonlinear parameter estima-tion method. Both sensitivity analysis and numerical experiments with simulated measurements containing random errors show that the method in the present invest-igation provides satisfactory accuracy of the estimated parameter Ntu, which characterizes the heat transfer per-formance of compact heat exchanger surfaces.
A multi-node model for transient heat transfer analysis of stratospheric airships
Alam, Mohammad Irfan; Pant, Rajkumar S.
2017-06-01
This paper describes a seven-node thermal model for transient heat transfer analysis of a solar powered stratospheric airship in floating condition. The solar array is modeled as a three node system, viz., outer layer, solar cell and substrate. The envelope is also modeled in three nodes, and the contained gas is considered as the seventh node. The heat transfer equations involving radiative, infra-red and conductive heat are solved simultaneously using a fourth order Runge-Kutta Method. The model can be used to study the effect of solar radiation, ambient wind, altitude and location of deployment of the airship on the temperature of the solar array. The model has been validated against some experimental data and numerical results quoted in literature. The effect of change in the value of some operational parameters on temperature of the solar array, and hence on its power output is also discussed.
Transient analysis of an HTS DC power cable with an HVDC system
Dinh, Minh-Chau; Ju, Chang-Hyeon; Kim, Jin-Geun; Park, Minwon; Yu, In-Keun; Yang, Byeongmo
2013-11-01
The operational characteristics of a superconducting DC power cable connected to a highvoltage direct current (HVDC) system are mainly concerned with the HVDC control and protection system. To confirm how the cable operates with the HVDC system, verifications using simulation tools are needed. This paper presents a transient analysis of a high temperature superconducting (HTS) DC power cable in connection with an HVDC system. The study was conducted via the simulation of the HVDC system and a developed model of the HTS DC power cable using a real time digital simulator (RTDS). The simulation was performed with some cases of short circuits that may have caused system damage. The simulation results show that during the faults, the quench did not happen with the HTS DC power cable because the HVDC controller reduced some degree of the fault current. These results could provide useful data for the protection design of a practical HVDC and HTS DC power cable system.
Markert, L. C.; Greene, J. E.; Ni, W.-X.; Hansson, G. V.; Sundgren, J.-E.
1991-01-01
Antimony surface segregation during Si(100) molecular beam epitaxy (MBE) was investigated at temperatures T(sub s) = 515 - 800 C using concentration transient analysis (CTA). The dopant surface coverage Theta, bulk fraction gamma, and incorporation probability sigma during MBE were determined from secondary-ion mass spectrometry depth profiles of modulation-doped films. Programmed T(sub s) changes during growth were used to trap the surface-segregated dopant overlayer, producing concentration spikes whose integrated area corresponds to Theta. Thermal antimony doping by coevaporation was found to result in segregation strongly dependent on T(sub s) with Theta(sub Sb) values up to 0.9 monolayers (ML): in films doped with Sb(+) ions accelerated by 100 V, Theta(sub Sb) was less than or equal to 4 x 10(exp -3) ML. Surface segregation of coevaporated antimony was kinematically limited for the film growth conditions in these experiments.
Transient analysis of single stage GM type double inlet pulse tube cryocooler
Gujarati, P. B.; Desai, K. P.; Naik, H. B.; Atrey, M. D.
2015-12-01
Transient analysis of single stage GM type double inlet pulse tube cryocooler is carried out using a one dimensional numerical model based on real gas properties of helium. The model solves continuity, momentum and energy equation for gas and solid to analyse the physical process occurring inside of the pulse tube cryocooler. Finite volume method is applied to discretize the governing equations with realistic initial and boundary conditions. Input data required for solving the model are the design data and operating parameters viz. pressure waveform from the compressor, regenerator matrix data, and system geometry including pulse tube, regenerator size and operating frequency for pulse tube cryocooler. The model investigates the effect of orifice opening, double inlet opening, pressure ratio, system geometry on no load temperature and refrigeration power at various temperatures for different charging pressure. The results are compared with experimental data and reasonable agreement is observed. The model can further be extended for designing two stage pulse tube cryocooler.
Optimization of high-resolution continuous flow analysis for transient climate signals in ice cores.
Bigler, Matthias; Svensson, Anders; Kettner, Ernesto; Vallelonga, Paul; Nielsen, Maibritt E; Steffensen, Jørgen Peder
2011-05-15
Over the past two decades, continuous flow analysis (CFA) systems have been refined and widely used to measure aerosol constituents in polar and alpine ice cores in very high-depth resolution. Here we present a newly designed system consisting of sodium, ammonium, dust particles, and electrolytic meltwater conductivity detection modules. The system is optimized for high-resolution determination of transient signals in thin layers of deep polar ice cores. Based on standard measurements and by comparing sections of early Holocene and glacial ice from Greenland, we find that the new system features a depth resolution in the ice of a few millimeters which is considerably better than other CFA systems. Thus, the new system can resolve ice strata down to 10 mm thickness and has the potential of identifying annual layers in both Greenland and Antarctic ice cores throughout the last glacial cycle.
A thermal-hydraulic code for transient analysis in a channel with a rod bundle
Energy Technology Data Exchange (ETDEWEB)
Khodjaev, I.D. [Research & Engineering Centre of Nuclear Plants Safety, Electrogorsk (Russian Federation)
1995-09-01
The paper contains the model of transient vapor-liquid flow in a channel with a rod bundle of core of a nuclear power plant. The computer code has been developed to predict dryout and post-dryout heat transfer in rod bundles of nuclear reactor core under loss-of-coolant accidents. Economizer, bubble, dispersed-annular and dispersed regimes are taken into account. The computer code provides a three-field representation of two-phase flow in the dispersed-annular regime. Continuous vapor, continuous liquid film and entrained liquid drops are three fields. For the description of dispersed flow regime two-temperatures and single-velocity model is used. Relative droplet motion is taken into account for the droplet-to-vapor heat transfer. The conservation equations for each of regimes are solved using an effective numerical technique. This technique makes it possible to determine distribution of the parameters of flows along the perimeter of fuel elements. Comparison of the calculated results with the experimental data shows that the computer code adequately describes complex processes in a channel with a rod bundle during accident.
Vogtle Electric Generating Plant ETE Analysis Review
Energy Technology Data Exchange (ETDEWEB)
Diediker, Nona H.; Jones, Joe A.
2006-12-09
Under contract with the Nuclear Regulatory Commission (NRC), staff from Pacific Northwest National Laboratory (PNNL) and Sandia National Laboratory (SNL)-Albuquerque reviewed the evacuation time estimate (ETE) analysis dated April 2006 prepared by IEM for the Vogtle Electric Generating Plant (VEGP). The ETE analysis was reviewed for consistency with federal regulations using the NRC guidelines in Review Standard (RS)-002, Supplement 2 and Appendix 4 to NUREG-0654, and NUREG/CR-4831. Additional sources of information referenced in the analysis and used in the review included NUREG/CR-6863 and NUREG/CR-6864. The PNNL report includes general comments, data needs or clarifications, and requests for additional information (RAI) resulting from review of the ETE analysis.
Directory of Open Access Journals (Sweden)
Daogang Lu
2014-01-01
Full Text Available The transient behaviors of natural circulation loop (NCL are important for the system reliability under postulated accidents. The heat loss and structure thermal inertia may influence the transient behaviors of NCL greatly, so a transient analysis model with consideration of heat loss was developed based on the MATLAB/Simulink to predict the thermal-hydraulic characteristic of liquid metal NCL. The transient processes including the start-up, the loss of pump, and the shutdown of thermal-hydraulic ADS lead bismuth loop (TALL experimental facility were simulated by using the model. A good agreement is obtained to validate the transient model. The appended structure would provide significant thermal inertia and flatten the temperature distribution in the transients. The oscillations of temperature and flow rate are also weakened. The temperature difference between hot leg and cold leg would increase with the decrease of heat loss, so the flow rate increases as well. However, a significant increase of hot section temperature may cause a failure of facility integrity due to the decrease of heat loss. Hence, the full power of the core tank may also be limited.
DEFF Research Database (Denmark)
Dorrell, David G.; Hermann, Alexander Niels August; Jensen, Bogi Bech
2013-01-01
There has been much literature on unbalanced magnetic pull in various types of electrical machine. This can lead to bearing wear and additional vibrations in the machine. In this paper a wound rotor induction is studied. Finite element analysis studies are conducted when the rotor has 10 % rotor...... eccentricity. The operating conditions are varied so that transient, motoring and doubly-fed induction generator modes are studied. This allows greater understanding of the radial forces involved. Wound rotor induction machines exhibit higher unbalanced magnetic pull than cage induction machines so...
De Capua, B; De Felice, C; Costantini, D; Bagnoli, F; Passali, D
2003-02-01
Hearing loss can be considered as the most common birth defect. Early detection of hearing loss by screening at, or shortly after, birth and appropriate intervention are critical to speech, language and cognitive development. In the present study, the characteristics of Transient Evoked Otoacoustic Emissions have been evaluated as a function of known pre- and perinatal risk factors for hearing loss. All newborns were screened for hearing loss using a physiologic test of hearing function, the Transient Evoked Otoacoustic Emissions. A total of 532 consecutive newborn infants received binaural Transient Evoked Otoacoustic Emission testing (262 males, 270 females; mean gestational age 39.2 +/- 2.1 weeks, range 26-43; birth weight: 3,240 +/- 550 g, range 910-4,780). The population examined comprised 448 control infants and 84 high-risk for hearing loss infants (Joint Committee on Infant Hearing 1994 criteria). All Transient Evoked Otoacoustic Emission recordings were performed at comparable postconceptional ages. Audiological screening by Transient Evoked Otoacoustic Emission recording showed an overall 100% sensitivity, 99.02% specificity, with negative and positive predictive values of 100% and 62.5%, respectively. As compared to controls, high-risk infants showed: 1. increased rates of Fail-1 (Transient Evoked Otoacoustic Emissions absent at first examination, 21.4% vs 9.8%, p = 0.004), Fail-2 (Transient Evoked Otoacoustic Emissions absent on retesting: 8.64% vs 1.37%, p = 0.0014), false positives (Transient Evoked Otoacoustic Emissions absent/V wave present: 3.7% vs 0.46%, p = 0.029) and true positives (Transient Evoked Otoacoustic Emissions absent, V wave absent: 2.47% or 24.5 per 1,000 live births vs 0.22% or 2.2 per 1,000 live births, p = 0.013); 2. significantly reduced Transient Evoked Otoacoustic Emission intensity in the 0.7-1 kHz (right side) and 1-2 kHz (left side) frequency ranges. Multivariate logistic regression analysis showed a significant positive
Techniques for Analysis of Plant Phenolic Compounds
Directory of Open Access Journals (Sweden)
Thomas H. Roberts
2013-02-01
Full Text Available Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.
Benchmarking of Modern Data Analysis Tools for a 2nd generation Transient Data Analysis Framework
Goncalves, Nuno
2016-01-01
During the past year of operating the Large Hadron Collider (LHC), the amount of transient accelerator data to be persisted and analysed has been steadily growing. Since the startup of the LHC in 2006, the amount of weekly data storage requirements exceeded what the systems was initially designed to accommodate in a full year of operation. Moreover, it is predicted that the data acquisition rates will continue to increase in the future, due to foreseen improvements in the infrastructure within the scope of the High Luminosity LHC project. Despite the efforts for improving and optimizing the current data storage infrastructures (CERN Accelerator Logging Service and Post Mortem database), some limitations still persist and require a different approach to scale up efficiently to provide efficient services for future machine upgrades. This project aims to explore one of the possibilities among novel solutions proposed to solve the problem of working with large datasets. The configuration is composed of Spark for ...
Transient stability analysis of electric energy systems via a fuzzy ART-ARTMAP neural network
Energy Technology Data Exchange (ETDEWEB)
Ferreira, Wagner Peron; Silveira, Maria do Carmo G.; Lotufo, AnnaDiva P.; Minussi, Carlos. R. [Department of Electrical Engineering, Sao Paulo State University (UNESP), P.O. Box 31, 15385-000, Ilha Solteira, SP (Brazil)
2006-04-15
This work presents a methodology to analyze transient stability (first oscillation) of electric energy systems, using a neural network based on ART architecture (adaptive resonance theory), named fuzzy ART-ARTMAP neural network for real time applications. The security margin is used as a stability analysis criterion, considering three-phase short circuit faults with a transmission line outage. The neural network operation consists of two fundamental phases: the training and the analysis. The training phase needs a great quantity of processing for the realization, while the analysis phase is effectuated almost without computation effort. This is, therefore the principal purpose to use neural networks for solving complex problems that need fast solutions, as the applications in real time. The ART neural networks have as primordial characteristics the plasticity and the stability, which are essential qualities to the training execution and to an efficient analysis. The fuzzy ART-ARTMAP neural network is proposed seeking a superior performance, in terms of precision and speed, when compared to conventional ARTMAP, and much more when compared to the neural networks that use the training by backpropagation algorithm, which is a benchmark in neural network area. (author)
Validation of coupled Relap5-3D code in the analysis of RBMK-1500 specific transients
Energy Technology Data Exchange (ETDEWEB)
Evaldas, Bubelis; Algirdas, Kaliatka; Eugenijus, Uspuras [Lithuanian Energy Institute, Kaunas (Lithuania)
2003-07-01
This paper deals with the modelling of RBMK-1500 specific transients taking place at Ignalina NPP. These transients include: measurements of void and fast power reactivity coefficients, change of graphite cooling conditions and reactor power reduction transients. The simulation of these transients was performed using RELAP5-3D code model of RBMK-1500 reactor. At the Ignalina NPP void and fast power reactivity coefficients are measured on a regular basis and, based on the total reactor power, reactivity, control and protection system control rods positions and the main circulation circuit parameter changes during the experiments, the actual values of these reactivity coefficients are determined. Graphite temperature reactivity coefficient at the plant is determined by changing graphite cooling conditions in the reactor cavity. This type of transient is very unique and important from the gap between fuel channel and the graphite bricks model validation point of view. The measurement results, obtained during this transient, allowed to determine the thermal conductivity coefficient for this gap and to validate the graphite temperature reactivity feedback model. Reactor power reduction is a regular operation procedure during the entire lifetime of the reactor. In all cases it starts by either a scram or a power reduction signal activation by the reactor control and protection system or by an operator. The obtained calculation results demonstrate reasonable agreement with Ignalina NPP measured data. Behaviours of the separate MCC thermal-hydraulic parameters as well as physical processes are predicted reasonably well to the real processes, occurring in the primary circuit of RBMK-1500 reactor. Reasonable agreement of the measured and the calculated total reactor power change in time demonstrates the correct modelling of the neutronic processes taking place in RBMK- 1500 reactor core. And finally, the performed validation of RELAP5-3D model of Ignalina NPP RBMK-1500
Electromechanical coupling model and analysis of transient behavior for inertial vibrating machines
Institute of Scientific and Technical Information of China (English)
HU Ji-yun; YU Cui-ping; YIN Xue-gang
2004-01-01
A mathematical model of electromechanical coupling system for a planar inertial vibrating machine is built by setting up dynamical equations of discrete systems with a matrix methodology proposed. The substance of the transient behavior of the machine is unveiled by analyzing the results of the computer simulation to the model, and new methods are presented for diminishing the transient amplitude of the vibrating machine and improving the transient behavior. The reliable mathematical model is provided for intelligent control of the transient behavior of the equipment.
Advanced Power Plant Development and Analysis Methodologies
Energy Technology Data Exchange (ETDEWEB)
A.D. Rao; G.S. Samuelsen; F.L. Robson; B. Washom; S.G. Berenyi
2006-06-30
Under the sponsorship of the U.S. Department of Energy/National Energy Technology Laboratory, a multi-disciplinary team led by the Advanced Power and Energy Program of the University of California at Irvine is defining the system engineering issues associated with the integration of key components and subsystems into advanced power plant systems with goals of achieving high efficiency and minimized environmental impact while using fossil fuels. These power plant concepts include 'Zero Emission' power plants and the 'FutureGen' H2 co-production facilities. The study is broken down into three phases. Phase 1 of this study consisted of utilizing advanced technologies that are expected to be available in the 'Vision 21' time frame such as mega scale fuel cell based hybrids. Phase 2 includes current state-of-the-art technologies and those expected to be deployed in the nearer term such as advanced gas turbines and high temperature membranes for separating gas species and advanced gasifier concepts. Phase 3 includes identification of gas turbine based cycles and engine configurations suitable to coal-based gasification applications and the conceptualization of the balance of plant technology, heat integration, and the bottoming cycle for analysis in a future study. Also included in Phase 3 is the task of acquiring/providing turbo-machinery in order to gather turbo-charger performance data that may be used to verify simulation models as well as establishing system design constraints. The results of these various investigations will serve as a guide for the U. S. Department of Energy in identifying the research areas and technologies that warrant further support.
A Taylor-Galerkin finite element algorithm for transient nonlinear thermal-structural analysis
Thornton, E. A.; Dechaumphai, P.
1986-01-01
A Taylor-Galerkin finite element method for solving large, nonlinear thermal-structural problems is presented. The algorithm is formulated for coupled transient and uncoupled quasistatic thermal-structural problems. Vectorizing strategies ensure computational efficiency. Two applications demonstrate the validity of the approach for analyzing transient and quasistatic thermal-structural problems.
Xue, H.; Popov, M.
2013-01-01
Large transient overvoltages are normally caused by vacuum circuit breaker (VCB) switching operation during disconnection of induction motors. In this paper VCBs, cables, generators, busbars, induction motors and surge arresters are modeled by making use of ATP-EMTP. Switching transient overvoltages
Analysis of transient gas-liquid two-phase natural circulation
Energy Technology Data Exchange (ETDEWEB)
Kataoka, Isao; Matsumoto, Tadayoshi; Morita, Yu; Kawashima, Atsushi [Department of Mechanophysics Engineering, Osaka University, Suita, Osaka (Japan); Nakayama, Akio
1999-07-01
Analyses were made on the transient behavior of two-phase natural circulation in annular passage. Drift flux model was used in the analyses and several correlations of drift velocity were used and compared. Transient variation of void fraction, inlet liquid flux and length of two-phase region were predicted based on simplified model. It was revealed that in transient two-phase natural circulation, the condition for pressure difference between inlet and outlet is quite important and difficult to be specified. A simplified model for inlet pressure condition was assumed and transient two-phase natural circulation was reasonably predicted. The correlation of drift velocity was shown to have important effect on the flow behavior particularly for the transient variation of two-phase length. (author)
Rosenberg, G. S.; Schoeberle, D. F.; Valentin, R. A.
1969-01-01
Analysis and solution are presented for transient thermal stresses in a free heat-generating flat plate and a free, hollow-generating cylinder as a result of sudden environmental changes. The technique used and graphical results obtained are of interest to the heat transfer industry.
DEFF Research Database (Denmark)
Hassager, Ole; Westborg, H
1987-01-01
An analysis of the transient rotating cylinder apparatus for the measurement of liquid-liquid interface viscosity is given. An analytical expression that allows the determination of the interfacial viscosity from observations of the interface movement is given. The expression is presented...... in tabular form for selected values of the physical parameters of the two phases, and suggestions for apparatus design are given....
An analytical solution of the Fokker-Planck equation in the phase-locked loop transient analysis
Zhang, Weijian
1987-01-01
A probabilistic approach is used to obtain an analytical solution to the Fokker-Planck equation used in the transient analysis of the phase-locked loop phase error process of the first-order phase-locked loop. The solution procedure, which is based on the Girsanov transformation, is described.
Mandjes, M.R.H.; Uitert, M.J.G. van
2000-01-01
The first part of the paper is devoted to a transient analysis of traffic generated by bursty sources. These sources are governed by a modulating process, whose state determines the traffic rate at which the source transmits. The class of modulating processes contains e.g. on/off traffic sources wit
Energy Technology Data Exchange (ETDEWEB)
Choi, Chiwoong; Ha, Kwiseok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2014-05-15
A safety analysis of ATWS for the recently designed Prototype GEN-IV Sodium Cooled Fast Reactor (PGSFR) was conducted. Unprotected Transient Over-Power (UTOP), Unprotected Loss OF Flow (ULOF), and Unprotected Loss Of Heat Sink (ULOHS) were selected as representative events for the ATWS. In an unprotected condition, the power in the core is only controlled by reactivity feedbacks, which are interacted with the thermal-hydraulic characteristics of the components in the plant. Heat is removed by the steam generator (SG) and decay heat removal system (DHRS). Therefore, the major objectives of the safety analysis of the ATWS events are to investigate the thermal hydraulic characteristics of the DHRS and the SG, the neutron kinetic characteristics of the reactivity feedback, and the interaction between the neutron kinetics, and the thermal-hydraulics during the events.
Transient Analysis of Thermal Protection System for X-33 Aircraft using MSC/NASTRAN
Miura, Hirokazu; Chargin, M. K.; Bowles, J.; Tam, T.; Chu, D.; Chainyk, M.; Green, Michael J. (Technical Monitor)
1997-01-01
X-33 is an advanced technology demonstrator vehicle for the Reusable Launch Vehicle (RLV) program. The thermal protection system (TPS) for the X-33 is composed of complex layers of materials to protect internal components, while withstanding severe external temperatures induced by aerodynamic heating during high speed flight. It also serves as the vehicle aeroshell in some regions using a stand-off design. MSC/NASTRAN thermal analysis capability was used to predict transient temperature distribution (within the TPS) throughout a mission, from launch through the cool-off period after landing. In this paper, a typical analysis model, representing a point on the vehicle where the liquid oxygen tank is closest to the outer mold line, is described. The maximum temperature difference between the outer mold line and the internal surface of the liquid oxygen tank can exceed 1500 F. One dimensional thermal models are used to select the materials and determine the thickness of each layer for minimum weight while insuring that all materials remain within the allowable temperature range. The purpose of working with three dimensional (3D) comprehensive models using MSC/NASTRAN is to assess the 3D radiation effects and the thermal conduction heat shorts of the support fixtures.
Transient analysis mode participation for modal survey target mode selection using MSC/NASTRAN DMAP
Barnett, Alan R.; Ibrahim, Omar M.; Sullivan, Timothy L.; Goodnight, Thomas W.
1994-01-01
Many methods have been developed to aid analysts in identifying component modes which contribute significantly to component responses. These modes, typically targeted for dynamic model correlation via a modal survey, are known as target modes. Most methods used to identify target modes are based on component global dynamic behavior. It is sometimes unclear if these methods identify all modes contributing to responses important to the analyst. These responses are usually those in areas of hardware design concerns. One method used to check the completeness of target mode sets and identify modes contributing significantly to important component responses is mode participation. With this method, the participation of component modes in dynamic responses is quantified. Those modes which have high participation are likely modal survey target modes. Mode participation is most beneficial when it is used with responses from analyses simulating actual flight events. For spacecraft, these responses are generated via a structural dynamic coupled loads analysis. Using MSC/NASTRAN DMAP, a method has been developed for calculating mode participation based on transient coupled loads analysis results. The algorithm has been implemented to be compatible with an existing coupled loads methodology and has been used successfully to develop a set of modal survey target modes.
Directory of Open Access Journals (Sweden)
Yan Wang
2017-01-01
Full Text Available After a postulated design basis accident leads high temperature gas cooled reactor to emergency shutdown, steam generator still remains with high temperature level and needs to be cooled down by a precooling before reactor restarts with clearing of fault. For the large difference of coolant temperature between inlet and outlet of steam generator in normal operation, the temperature distribution on the components of steam generator is very complicated. Therefore, the temperature descending rate of the components in steam generator needs to be limited to avoid the potential damage during the precooling stage. In this paper, a pebble-bed high temperature gas cooled reactor is modeled by thermal-hydraulic system analysis code and several postulated precooling injection transients are simulated and compared to evaluate their effects, which will provide support for the precooling design. The analysis results show that enough precooling injection is necessary to satisfy the precooling requirements, and larger mass flow rate of precooling water injection will accelerate the precooling process. The temperature decrease of steam generator is related to the precooling injection scenarios, and the maximal mass flow rate of the precooling injection should be limited to avoid the excessively quick temperature change of the structures in steam generator.
Transient analysis of a queue with queue-length dependent MAP and its application to SS7 network
Directory of Open Access Journals (Sweden)
Bong Dae Choi
1999-01-01
Full Text Available We analyze the transient behavior of a Markovian arrival queue with congestion control based on a double of thresholds, where the arrival process is a queue-length dependent Markovian arrival process. We consider Markov chain embedded at arrival epochs and derive the one-step transition probabilities. From these results, we obtain the mean delay and the loss probability of the nth arrival packet. Before we study this complex model, first we give a transient analysis of an MAP/M/1 queueing system without congestion control at arrival epochs. We apply our result to a signaling system No. 7 network with a congestion control based on thresholds.
DEFF Research Database (Denmark)
Sardar, Partha; Nairooz, Ramez; Chatterjee, Saurav
2014-01-01
Dabigatran is a novel oral anticoagulant and may be useful during atrial fibrillation (AF) ablation for prevention of thromboembolic events. However, the benefits and adverse effects of periprocedural dabigatran therapy have not been thoroughly evaluated. A meta-analysis was performed to evaluate...... with warfarin for AF ablation. A total of 5,513 patients undergoing catheter ablation were included in 17 observational studies and 1 randomized trial. Fourteen events of stroke or transient ischemic attacks were reported in the dabigatran group and 4 in the warfarin group (Peto's odds ratio 3.94, 95...... complications including stroke and transient ischemic attack....
Transient Analysis of Axially Moving Materials Interacting with External Dynamic Components
Zhu, Weidong
A new transient analysis, that overcomes the limitations of the spatially discretized models, is developed in the present study for the response of axially moving materials interacting with external dynamic components. First, the complex response of a time-varying, cable transport system, such as a tramway or cable car, is predicted from the model of an axially moving string transporting a damped, linear oscillator under arbitrary initial conditions, external forces and boundary excitations. A delay-integral equation describing the force of interaction between the cable and the payload is derived using the Green's function for the traveling string. Repeated scattering of transverse waves in the string at the payload is represented by the delay terms. The solution technique within the framework of the theory of distributions is developed for the delay -integral equation with discontinuous kernel and dependent variable. The forcing integrals are evaluated by both distribution and series expansion methods. Limitations of the series expansion approach are explored. Exact in the spatial domain, a temporal finite difference algorithm is presented for the solution of a resulting delay-integro -differential equation with discontinuous dependent variable. Special condition for the initial conditions of the system leading to vanishing slopes of the propagating wavefronts and consequently absence of the discontinuities in the interaction force is obtained. Second, the transient response of a translating string in contact with rigid and flexible constraints is determined for arbitrary initial conditions, external forces and boundary disturbances. The model represents the translating magnetic tape-head systems in computer data storage devices. The contact force between the string and a one-sided constraint is composed of a static preload component existing at the equilibrium and a dynamic component. The exact expression describing the dynamic contact force component is derived
Directory of Open Access Journals (Sweden)
Jeong Soon Park
2016-04-01
Full Text Available The failure probabilities of the reactor pressure vessel (RPV for low temperature over-pressurization (LTOP and cool-down transients are calculated in this study. For the cool-down transient, a pressure–temperature limit curve is generated in accordance with Section XI, Appendix G of the American Society of Mechanical Engineers (ASME code, from which safety margin factors are deliberately removed for the probabilistic fracture mechanics analysis. Then, sensitivity analyses are conducted to understand the effects of some input parameters. For the LTOP transient, the failure of the RPV mostly occurs during the period of the abrupt pressure rise. For the cool-down transient, the decrease of the fracture toughness with temperature and time plays a main role in RPV failure at the end of the cool-down process. As expected, the failure probability increases with increasing fluence, Cu and Ni contents, and initial reference temperature-nil ductility transition (RTNDT. The effect of warm prestressing on the vessel failure probability for LTOP is not significant because most of the failures happen before the stress intensity factor reaches the peak value while its effect reduces the failure probability by more than one order of magnitude for the cool-down transient.
Energy Technology Data Exchange (ETDEWEB)
Djukanovic, M. (Inst. ' Nikola Tesla' , Belgrade (Yugoslavia)); Sobajic, D.J.; Yohhan Pao (Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Electrical Engineering and Applied Physics Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Computer Engineering and Science AI WARE inc., Cleveland, OH (United States))
1992-10-01
In heavily stressed power systems, post-fault transient voltage dips can lead to undesired tripping of industrial drives and large induction motors. The lowest transient voltage dips occur when fault clearing times are less than critical ones. In this paper, we propose a new iterative analytical methodology to obtain more accurate estimates of voltage dips at maximum angular swing in direct transient stability analysis. We also propose and demonstrate the possibility of storing the results of these computations in the associative memory (AM) system, which exhibits remarkable generalization capabilities. Feature-based models stored in the AM can be utilized for fast and accurate prediction of the location, duration and the amount of the worst voltage dips, thereby avoiding the need and cost for lengthy time-domain simulations. Numerical results obtained using the example of the New England power system are presented to illustrate our approach. (Author)
Dailey, Brian T.
The observed cutoff in the cosmic ray spectrum leads to a highly motivated expectation of an ultra-high energy (UHE) neutrino flux, coming from interactions between the cosmic rays and cosmic microwave background photons. Although no UHE neutrinos have yet been detected; better background separation and removal will help accelerate the search. Past flights of the ANtarctic Impulsive Transient Antenna (ANITA) experiment have set the strongest limits on the UHE neutrino flux above 1019 eV. Due to the advanced sensitivity of future flights to both signal and anthropogenic backgrounds, the techniques used in the past analyses may not be sufficient to remove backgrounds. Here, we discuss processes developed for this analysis. First, we discuss newly techniques to filter event waveforms in both the amplitude and phase spectra. These new techniques were applied to the ANITA-2 experiment data set. We discuss a new technique developed that uses equal area bins of ice on the Antarctic continent. Further, we define a set of analysis cuts, how the analysis cuts were optimized for maximum sensitivity for UHE neutrinos, how the number of background and neutrino events were estimated. For our search, we used the maximal Kotera et. al. 2010 flux model and optimized based on this model. After optimization, we found zero events from the 10% sample passing all cuts. These techniques will prove useful for future flights of ANITA as the sensitivity of the instrument increases. The optimization procedure can also provide a starting point for future analysis. The filtering technique shown here decreased mis-reconstruction in pointing of events. The HealPix method, while requiring further refinement, shows promise by retaining valuable areas of ice that may have been removed from previous analyses.
基于模糊熵的核电站瞬态识别方法%Fuzzy Entropy Based Transient Identification in Nuclear Power Plant
Institute of Scientific and Technical Information of China (English)
常远; 郝轶; 黄晓津; 李春文; 梁记兴; 刘景源
2014-01-01
For safe and economical operation of nuclear power plants (NPPs) ,the occur-ring anomalies should be promptly and correctly identified .In this paper ,the transients were identified by processing time series of critical variables .First ,based on its ability to measure the complexity of time series ,the fuzzy entropy (FuzzyEn) was used to determine whether the system was in normal state . Then cross fuzzy entropy was employed for classifying the occurring transients , using its ability to characterize the similarity between two time series .The feasibility and effectiveness were verified by simulator data of pebble-bed modular high temperature gas-cooled reactor nuclear power plant (HTR-PM ) .It is demonstrated that the proposed method is effective for transient identification and it dispenses with a complex training phase .%为保障核电站安全经济运行，需及时准确地识别核电站出现的异常。本文通过处理关键变量的时间序列数据，对瞬态过程进行识别：利用模糊熵度量时间序列复杂度的能力，判断系统是否处于正常状态；进而利用互模糊熵度量两时间序列相似度的能力，对出现的瞬态进行类型识别。利用模块式高温气冷堆核电站仿真机的数据验证了本方法的可行性和有效性，结果表明本文方法可有效进行瞬态识别，且不需复杂的训练过程。
Quantum analysis of a plant metacommunity
Directory of Open Access Journals (Sweden)
Kürşad Özkan
2016-01-01
Full Text Available A wide variety of statistical methods have been frequently used in the area of ecology. Especially probability based analytic approaches have been become more popular in the ecological studies in recent years. On the other hand, the core of quantum is based on calculation of energy footprint by probability approach. That is why it has been expected that quantum analysis will have found a significant place in the ecological studies in the future. As a result, the book of quantum ecology written by László Orlóci Frsc made a profound contribution to enter within this process. This study aims at calculations of the potential energy footprints of specific processes including phylogeny, environmental mediation and emergent effects by using quantum analysis for a plant metacommunity. In this study, the fundamental formulate was based on Max Planck’s energy based entropy modified by László Orlóci Frsc. A plant metacommunity example includes 3 complexes taken from various slope positions of Yazılı Canyon Nature Park located in the Lake districts was subjected to quantum analysis. Energy structure parameters were calculated for each complex. Variations among the complexes’ H(cx energy footprints were found insignificant. Calculations at the level of catena was shown that potential energy footprint of phylogeny overwhelms the effect of slope position in the nH terms. However this is turned in favor of the slope position gradient when the H footprints are compared. In the study, stability values of the complexes were also calculated and, the highest instability value was found for the complex taken from valley bottom of the canyon.
Institute of Scientific and Technical Information of China (English)
邓松圣; 周绍骑; 廖振方; 邱正阳; 曾顺鹏
2004-01-01
Hydraulic transient,which is resulted from sudden increase of inlet pressure for laminar pipeline flow,is studied.The partial differential equation,initial and boundary conditions for transient pressure were constructed,and the theoretical solution was obtained by variable-separation method.The partial differential equation,initial and boundary conditions for flow rate were obtained in accordance with the constraint correlation between flow rate and pressure while the transient flow rate distribution was also solved by variable-separation method.The theoretical solution conforms to numerical solution obtained by method of characteristics(MOC)very well.
Application of the coupled code RELAP5-QUABOX/CUBBOX in the system analysis of nuclear power plants
Energy Technology Data Exchange (ETDEWEB)
Bencik, V.; Feretic, D.; Debrecin, N. [Faculty of Electrical Engineering and Computing, Zagreb (Croatia)
2002-11-01
Best estimate codes and methods for the realistic simulation of operational transients and accidents are being developed in two directions. First, computer codes with models of the interaction between multidimensional neutron kinetic and NPP dynamic behavior enable realistic simulation of transients characterized by strong coupling between neutronics and thermal-hydraulics as well as of transients that result in asymmetrical spatial core power distribution. Coupled codes consisting of a system thermal-hydraulic code and a multidimensional neutronic code are being developed worldwide in order to accomplish that task. Secondly, development of the qualified plant nodalization and of the models of plant protection and control systems is important for the realistic system analysis of operational transients and accidents. Comparison of the coupled code and point kinetic results is important for the validation of the coupled code and to gain more experience in the use of the coupled code in realistic analyses. In this paper the results of two transients for NPP Krsko using the coupled code RELAP5-QUABOX/CUBBOX (R5QC) and RELAP5 stand alone code are discussed. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Mahaffy, J. [Pennsylvania State Univ., University Park, PA (United States); Boyack, B.E.; Steinke, R.G. [Los Alamos National Lab., NM (United States)
1998-05-01
The objective of this document is to ease the task of adding new system components to the Transient Reactor Analysis Code (TRAC) or altering old ones. Sufficient information is provided to permit replacement or modification of physical models and correlations. Within TRAC, information is passed at two levels. At the upper level, information is passed by system-wide and component-specific data modules at and above the level of component subroutines. At the lower level, information is passed through a combination of module-based data structures and argument lists. This document describes the basic mechanics involved in the flow of information within the code. The discussion of interfaces in the body of this document has been kept to a general level to highlight key considerations. The appendices cover instructions for obtaining a detailed list of variables used to communicate in each subprogram, definitions and locations of key variables, and proposed improvements to intercomponent interfaces that are not available in the first level of code modernization.
Greene, William H.
1989-01-01
A study has been performed focusing on the calculation of sensitivities of displacements, velocities, accelerations, and stresses in linear, structural, transient response problems. One significant goal was to develop and evaluate sensitivity calculation techniques suitable for large-order finite element analyses. Accordingly, approximation vectors such as vibration mode shapes are used to reduce the dimensionality of the finite element model. Much of the research focused on the accuracy of both response quantities and sensitivities as a function of number of vectors used. Two types of sensitivity calculation techniques were developed and evaluated. The first type of technique is an overall finite difference method where the analysis is repeated for perturbed designs. The second type of technique is termed semianalytical because it involves direct, analytical differentiation of the equations of motion with finite difference approximation of the coefficient matrices. To be computationally practical in large-order problems, the overall finite difference methods must use the approximation vectors from the original design in the analyses of the perturbed models.
Bhagat, Shaum; Bass, Johnnie; Qaddoumi, Ibrahim; Brennan, Rachel; Wilson, Matthew; Wu, Jianrong; Galindo, Carlos-Rodriguez; Paglialonga, Alessia; Tognola, Gabriella
2013-01-01
The aims of this study were to characterize and quantify time-frequency changes in transient-evoked otoacoustic emissions (TEOAEs) recorded in children diagnosed with retinoblastoma who were receiving carboplatin chemotherapy. A signal processing technique, the wavelet transform (WT), was used to analyze TEOAE waveforms in narrow-band frequency components. Ten children (aged 3-72 months) diagnosed with unilateral or bilateral retinoblastoma were enrolled in the study. TEOAEs were acquired from the children with linear sequences of 70 dB peak equivalent SPL clicks. After WT analysis, TEOAE energy, latency and normalized energy in the narrow-band frequency components were compared before and during carboplatin chemotherapy treatment (average dose 1693 mg/m2). On a group basis, no significant differences (p>0.05) in the TEOAE energy, latency or normalized energy before and after carboplatin treatment were observed. There were decreases in normalized energy on an individual basis in 10 out of 18 ears in the sample. Exposure to carboplatin chemotherapy did not cause significant changes in TEOAE energy, latency and normalized energy during treatment. However, long-term monitoring of hearing with measurements of TEOAEs is warranted, given the risks of delayed hearing loss in some children receiving carboplatin chemotherapy.
Transient Thermal Analysis of 3-D Integrated Circuits Packages by the DGTD Method
Li, Ping
2017-03-11
Since accurate thermal analysis plays a critical role in the thermal design and management of the 3-D system-level integration, in this paper, a discontinuous Galerkin time-domain (DGTD) algorithm is proposed to achieve this purpose. Such as the parabolic partial differential equation (PDE), the transient thermal equation cannot be directly solved by the DGTD method. To address this issue, the heat flux, as an auxiliary variable, is introduced to reduce the Laplace operator to a divergence operator. The resulting PDE is hyperbolic, which can be further written into a conservative form. By properly choosing the definition of the numerical flux used for the information exchange between neighboring elements, the hyperbolic thermal PDE can be solved by the DGTD together with the auxiliary differential equation. The proposed algorithm is a kind of element-level domain decomposition method, which is suitable to deal with multiscale geometries in 3-D integrated systems. To verify the accuracy and robustness of the developed DGTD algorithm, several representative examples are benchmarked.
Discrete homotopy analysis for optimal trading execution with nonlinear transient market impact
Curato, Gianbiagio; Gatheral, Jim; Lillo, Fabrizio
2016-10-01
Optimal execution in financial markets is the problem of how to trade a large quantity of shares incrementally in time in order to minimize the expected cost. In this paper, we study the problem of the optimal execution in the presence of nonlinear transient market impact. Mathematically such problem is equivalent to solve a strongly nonlinear integral equation, which in our model is a weakly singular Urysohn equation of the first kind. We propose an approach based on Homotopy Analysis Method (HAM), whereby a well behaved initial trading strategy is continuously deformed to lower the expected execution cost. Specifically, we propose a discrete version of the HAM, i.e. the DHAM approach, in order to use the method when the integrals to compute have no closed form solution. We find that the optimal solution is front loaded for concave instantaneous impact even when the investor is risk neutral. More important we find that the expected cost of the DHAM strategy is significantly smaller than the cost of conventional strategies.
Energy Technology Data Exchange (ETDEWEB)
Prakash, J.; Torzillo, G.; Pushparaj, B.; Carlozzi, P.; Materassi, R. [Consiglio Nazionale delle Ricerche, Florence (Italy). Centro di Studio dei Microhanismi Autotrofi
1995-08-01
A mathematical model to make a transient thermal analysis and to estimate the incident solar energy for two designs of tubular photobioreactor installed outdoors is presented here. In the first photobioreactor design the tubes were arranged in one plane, whereas in the second the tubes were arranged in two planes. The model was validated by comparing the experimental data and predicted values of culture temperature. Both the input solar energy and culture temperature in a tubular photobioreactor may be predicted with a reasonable degree of accuracy by employing the model. The performance of the two photobioreactors for mass culture of Spirulina was also studied in relation to their design and culture temperature. The average biomass yield obtained in one-plane and two-plane photobioreactors were (dry weight) 23.7 g m{sup -2} day{sup -1} and 27.8 g m{sup -2} day{sup -1} respectively. Such biomass yields corresponded to a volumetric productivity of (dry weight) 0.466 g litre{sup -1} day{sup -1} in the one-plane reactor and 1.5 g litre{sup -1} day{sup -1} in the two-plane reactor. We further observed that biomass yield could be increased by about 21% when the culture temperature was maintained at the optimal value of 35{sup o}C compared to another culture in which temperature changed according to the ambient temperature from 20 to 39{sup o}C during the day. (author)
Directory of Open Access Journals (Sweden)
Sona Padma
2011-01-01
Full Text Available Problem statement: FACTS devices play a major role in the efficient operation of the complex power system. FACTS devices such as STATCOM, SSSC and IPFC are in increasing usage. With energy storage systems they have a good control over the real as well as reactive power compensation and transient stability improvement. The design of controller for the SSSC with SMES system is analyzed in this study. Approach: The main variables to be controlled in the power system for efficient operation are the voltage, phase angle and impedance. A SSSC is a series connected converter based FACTS control which can provide a series reactive power compensation for a transmission system. With the addition of energy storage device, in addition to the reactive power compensation the real power exchange is also accomplished. Fuzzy logic controller is designed for the efficient operation of the power system with SSSC integrated with energy storage device. From the power reference the current reference is calculated and the error and change in error in the current are calculated in the controller. Results: A three phase to ground fault is simulated in the test system. A comparative analysis of the PI and fuzzy logic control of SSSC with energy storage system for the rotor angle oscillation damping following the disturbance is done. Conclusion: The fuzzy logic controller works efficiently compared to the conventional PI controller for the SSSC with SMES system. Also with energy storage system in the FACTS devices, the efficient operation of the power system is possible.
Transient-pressure analysis in geothermal steam reservoirs with an immobile vaporizing liquid phase
Moench, A.F.; Atkinson, P.G.
1978-01-01
A finite-difference model for the radial horizontal flow of steam through a porous medium is used to evaluate transient-pressure behavior in the presence of an immobile vaporizing or condensing liquid phase. Graphs of pressure drawdown and buildup in terms of dimensionless pressure and time are obtained for a well discharging steam at a constant mass flow rate for a specified time. The assumptions are made that the steam is in local thermal equilibrium with the reservoir rocks, that temperature changes are due only to phase change, and that effects of vapor-pressure lowering are negligible. Computations show that when a vaporizing liquid phase is present the pressure drawdown exhibits behavior similar to that observed in noncondensable gas reservoirs, but delayed in time. A theoretical analysis allows for the computation of this delay and demonstrates that it is independent of flow geometry. The response that occurs upon pressure buildup is markedly different from that in a noncondensable gas system. This result may provide a diagnostic tool for establishing the existence of phase-change phenomena within a reservoir. ?? 1979.
Wave-formed sediment ripples: Transient analysis of ripple spectral development
Davis, Joseph P.; Walker, David J.; Townsend, Murray; Young, Ian R.
2004-07-01
A new method has been developed that models the changes a wave-formed rippled sediment bed undergoes as it is actively evolving between two given equilibrium states due to a change in surface wave conditions. The transient analysis of rippled beds has received very little attention within the literature. Dynamic changes within ripple parameters have implications for the estimation of flow dissipation and sediment transport by changing the bottom roughness height. The method uses the spectral density function of the rippled bed and is based on a series of ripple growth and ripple transition experimental tests. The ripple evolution model was developed from the well-known Logistic Growth Law. Fitting the general solution of the logistic nonlinear differential equation to the experimental data enabled the evolution rate of the bed to be determined for each experimental test. It was concluded that there was no difference between the evolution rate determined from the ripple growth tests and the ripple transition tests. This indicated that the two types of growth are special cases of the same evolution processes, which is adequately modeled by the logistic growth equation. A functional dependence was established between the ripple evolution rate and the Shields parameter. This allows the evolution rate to be estimated from flow and sediment properties. The estimation of the rate at which rippled sediment beds evolve under a variable sea state has the potential to lead to significant improvements to the way ripple transition and hence bottom roughness is approximated in coastal wave models.
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
The accuracy and diagnostic values of transcranial Doppler (TCD) in transient ischemic attack (TIA) caused by the stenosis or occlusion of intracranial or extracranial blood vessels were investigated. Of the 50 TIA patients receiving routine TCD examinations, 39 cases (77 %) were diagnosed as having unilateral or bilateral stenosis or occlusion of MCA, ACA, siphon segment of internal carotid artery, which was furthermore confirmed by digital subtraction angiography (DSA) or MRA, 11 (22 %) cases were normal. An analysis on the TCD findings of the flow patterns and hemodynamic changes of the stenotic or occluded blood vessels was made in comparison with that obtained by angiography. It was showed that angiography demonstrated 17 unilateral MCA stenosis, 47 bilateral multi-stenosis, 1 occlusion of the siphon segment of the internal carotid artery, while TCD revealed 17 unilateral stenosis, 64 bilateral stenosis, 1 occlusion respectively, with an accordance rate of 78.7 %. It was concluded that the hemodynamic changes secondary to the stenosis of the basalcranial arteries, especially the moderate to severe stenosis or occlusion, might be an important risk factor for TIA. TCD examination achieved significant clinic values in the diagnosing of TIA.
Smith, Clifford B.; Wereley, Norman M.
1996-10-01
The first objective of this paper is to evaluate the performance of damping identification algorithms. The second objective is to determine the feasibility of damping augmentation in rotating composite beams via passive constrained layer damping (PCLD). Damping identification schemes were applied to four rectangular cross-section laminated composite beams with cocured integral damping layers over the span of the beam. The cocured beam consisted of a twenty-ply balanced and symmetric cross-ply Gr/Ep composite host structure, a top and bottom damping layer of viscoelastic material (VEM), and a 2-ply Gr/Ep constraining layer sandwiching the viscoelastic material to the host structure. Four VEM thicknesses were considered: 0, 5, 10, and 15 mils. The cantilevered beams were tested at rotational speeds ranging from 0 to 900 RPM in a vacuum chamber. Excitation in bending was provided using piezo actuators, and the bending response was measured using full strain gauge bridges. Transient data were analysed using logarithmic decrement, a Hilbert transform technique, and an FFT- based moving block analysis. When compared to the beam with no VEM, a 19.2% volume fraction (15 mil layer) of viscoelastic in the beam produced a 400% increase in damping ratio in the non-rotating case, while at 900 RPM, the damping ratio increased only 360%. Overall structural damping was reduced as a function of RPM, due to centrifugal stiffening.
Reliability analysis of wastewater treatment plants.
Oliveira, Sílvia C; Von Sperling, Marcos
2008-02-01
This article presents a reliability analysis of 166 full-scale wastewater treatment plants operating in Brazil. Six different processes have been investigated, comprising septic tank+anaerobic filter, facultative pond, anaerobic pond+facultative pond, activated sludge, upflow anaerobic sludge blanket (UASB) reactors alone and UASB reactors followed by post-treatment. A methodology developed by Niku et al. [1979. Performance of activated sludge process and reliability-based design. J. Water Pollut. Control Assoc., 51(12), 2841-2857] is used for determining the coefficients of reliability (COR), in terms of the compliance of effluent biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP) and fecal or thermotolerant coliforms (FC) with discharge standards. The design concentrations necessary to meet the prevailing discharge standards and the expected compliance percentages have been calculated from the COR obtained. The results showed that few plants, under the observed operating conditions, would be able to present reliable performances considering the compliance with the analyzed standards. The article also discusses the importance of understanding the lognormal behavior of the data in setting up discharge standards, in interpreting monitoring results and compliance with the legislation.
Wavelet transform analysis of transient signals: the seismogram and the electrocardiogram
Energy Technology Data Exchange (ETDEWEB)
Anant, K.S.
1997-06-01
In this dissertation I quantitatively demonstrate how the wavelet transform can be an effective mathematical tool for the analysis of transient signals. The two key signal processing applications of the wavelet transform, namely feature identification and representation (i.e., compression), are shown by solving important problems involving the seismogram and the electrocardiogram. The seismic feature identification problem involved locating in time the P and S phase arrivals. Locating these arrivals accurately (particularly the S phase) has been a constant issue in seismic signal processing. In Chapter 3, I show that the wavelet transform can be used to locate both the P as well as the S phase using only information from single station three-component seismograms. This is accomplished by using the basis function (wave-let) of the wavelet transform as a matching filter and by processing information across scales of the wavelet domain decomposition. The `pick` time results are quite promising as compared to analyst picks. The representation application involved the compression of the electrocardiogram which is a recording of the electrical activity of the heart. Compression of the electrocardiogram is an important problem in biomedical signal processing due to transmission and storage limitations. In Chapter 4, I develop an electrocardiogram compression method that applies vector quantization to the wavelet transform coefficients. The best compression results were obtained by using orthogonal wavelets, due to their ability to represent a signal efficiently. Throughout this thesis the importance of choosing wavelets based on the problem at hand is stressed. In Chapter 5, I introduce a wavelet design method that uses linear prediction in order to design wavelets that are geared to the signal or feature being analyzed. The use of these designed wavelets in a test feature identification application led to positive results. The methods developed in this thesis; the
Institute of Scientific and Technical Information of China (English)
HU Ji-yun; YIN Xue-gang; YU Cui-ping
2005-01-01
The dynamical equations for a inertial reciprocating machine excited by two rotating eccentric weights were built by the matrix methodology for establishing dynamical equations of discrete systems. A mathematical model of electromechanical coupling system for the machine was formed by combining the dynamical equations with the state equations of the two motors. The computer simulation to the model was performed for several values of the damping coefficient or the motor power, respectively. The substance of transient behavior of the machine is unveiled by analyzing the results of the computer simulation, and new methods are presented for diminishing the transient amplitude of the vibrating machine and improving the transient behavior. The reliable mathematical model is provided for intelligent control of the transient behavior and engineering design of the equipment.
Correlation analysis of transient heat transfer characteristics for air precooling aggregate
Guo, Chaohong; Zeng, Miao; Lu, Fei; Tang, Dawei; Guan, Wei; Li, Li; Fu, Tingwu
2017-04-01
In dam works, air precooling of aggregate is a common and effective method to avoid temperature cracks in concrete structure. In order to offer a reliable design theory for the air precooling process to avoid unreasonable energy consumption, the transient heat transfer characteristics of the aggregate are intensively analyzed. The combined structure of the aggregate and the interstitial space in the hopper is treated as a porous structure, and the space-average method is used to simulate the transient heat transfer process. Simulation results show that size of the hopper and the average air velocity in the cross section have great influence on the transient heat transfer process of the aggregate, while the porosity in the range of 0.4‒0.5 has little influence. Nomograms are abstracted from simulation results, and then correlations of the compared excess temperature are precisely fitted to predict the air precooling transient heat transfer process of the aggregate.
Cynod: A Neutronics Code for Pebble Bed Modular Reactor Coupled Transient Analysis
Energy Technology Data Exchange (ETDEWEB)
Hikaru Hiruta; Abderrafi M. Ougouag; Hans D. Gougar; Javier Ortensi
2008-09-01
The Pebble Bed Reactor (PBR) is one of the two concepts currently considered for development into the Next Generation Nuclear Plant (NGNP). This interest is due, in particular, to the concept’s inherent safety characteristics. In order to verify and confirm the design safety characteristics of the PBR computational tools must be developed that treat the range of phenomena that are expected to be important for this type of reactors. This paper presents a recently developed 2D R-Z cylindrical nodal kinetics code and shows some of its capabilities by applying it to a set of known and relevant benchmarks. The new code has been coupled to the thermal hydraulics code THERMIX/KONVEK[1] for application to the simulation of very fast transients in PBRs. The new code, CYNOD, has been written starting with a fixed source solver extracted from the nodal cylindrical geometry solver contained within the PEBBED code. The fixed source solver was then incorporated into a kinetic solver.. The new code inherits the spatial solver characteristics of the nodal solver within PEBBED. Thus, the time-dependent neutron diffusion equation expressed analytically in each node of the R-Z cylindrical geometry sub-domain (or node) is transformed into one-dimensional equations by means of the usual transverse integration procedure. The one-dimensional diffusion equations in each of the directions are then solved using the analytic Green’s function method. The resulting equations for the entire domain are then re-cast in the form of the Direct Coarse Mesh Finite Difference (D-CMFD) for convenience of solution. The implicit Euler method is used for the time variable discretization. In order to correctly treat the cusping effect for nodes that contain a partially inserted control rod a method is used that takes advantage of the Green’s function solution available in the intrinsic method. In this corrected treatment, the nodes are re-homogenized using axial flux shapes reconstructed based on the
Seismic analysis of nuclear power plant structures
Go, J. C.
1973-01-01
Primary structures for nuclear power plants are designed to resist expected earthquakes of the site. Two intensities are referred to as Operating Basis Earthquake and Design Basis Earthquake. These structures are required to accommodate these seismic loadings without loss of their functional integrity. Thus, no plastic yield is allowed. The application of NASTRAN in analyzing some of these seismic induced structural dynamic problems is described. NASTRAN, with some modifications, can be used to analyze most structures that are subjected to seismic loads. A brief review of the formulation of seismic-induced structural dynamics is also presented. Two typical structural problems were selected to illustrate the application of the various methods of seismic structural analysis by the NASTRAN system.
Thermodynamic Analysis of Combined Cycle Power Plant
Directory of Open Access Journals (Sweden)
A.K.Tiwari,
2010-04-01
Full Text Available Air Bottoming Cycle (ABC can replace the heat recovery steam generator and the steam turbine of the conventionalcombined cycle plant. The exhaust energy of the topping gas turbine of existing combine cycle is sent to gas-air heat exchange, which heats the air in the secondary gas turbine cycle. In 1980’s the ABC was proposed as an alternative for the conventional steam bottoming cycle. In spite of the cost of reducing hardware installations it could achieve a thermal efficiency of 80%. The complete thermodynamic analysis of the system has been performed by using specially designed programme, enabling the variation of main independent variables. The result shows the gain in net work output as well as efficiency of combined cycle is 35% to 68%.
Waste Isolation Pilot Plant Safety Analysis Report
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-11-01
The following provides a summary of the specific issues addressed in this FY-95 Annual Update as they relate to the CH TRU safety bases: Executive Summary; Site Characteristics; Principal Design and Safety Criteria; Facility Design and Operation; Hazards and Accident Analysis; Derivation of Technical Safety Requirements; Radiological and Hazardous Material Protection; Institutional Programs; Quality Assurance; and Decontamination and Decommissioning. The System Design Descriptions`` (SDDS) for the WIPP were reviewed and incorporated into Chapter 3, Principal Design and Safety Criteria and Chapter 4, Facility Design and Operation. This provides the most currently available final engineering design information on waste emplacement operations throughout the disposal phase up to the point of permanent closure. Also, the criteria which define the TRU waste to be accepted for disposal at the WIPP facility were summarized in Chapter 3 based on the WAC for the Waste Isolation Pilot Plant.`` This Safety Analysis Report (SAR) documents the safety analyses that develop and evaluate the adequacy of the Waste Isolation Pilot Plant Contact-Handled Transuranic Wastes (WIPP CH TRU) safety bases necessary to ensure the safety of workers, the public and the environment from the hazards posed by WIPP waste handling and emplacement operations during the disposal phase and hazards associated with the decommissioning and decontamination phase. The analyses of the hazards associated with the long-term (10,000 year) disposal of TRU and TRU mixed waste, and demonstration of compliance with the requirements of 40 CFR 191, Subpart B and 40 CFR 268.6 will be addressed in detail in the WIPP Final Certification Application scheduled for submittal in October 1996 (40 CFR 191) and the No-Migration Variance Petition (40 CFR 268.6) scheduled for submittal in June 1996. Section 5.4, Long-Term Waste Isolation Assessment summarizes the current status of the assessment.
Vinck, B M; Van Cauwenberge, P B; Corthals, P; De Vel, E
1998-01-01
Evaluation of cochlear hearing loss by means of transiently evoked otoacoustic emissions is already established in clinical practice. However, accurate prediction of pure-tone thresholds is still questioned and is still regarded as troublesome. Both click- and tone-burst-evoked otoacoustic emissions at several intensity levels were measured and analysed in 157 ears from normally hearing and 432 ears from patients with different degrees of pure sensory hearing loss using the ILO88/92 equipment. Results of otoacoustic emissions (OAE), elicited by clicks and tone-bursts at centre frequencies from 1 to 5 kHz, were analysed using two different statistical methods. Both multivariate discriminant analysis and forward multiple regression analysis were used to determine which OAE variables were most discriminating and best at predicting hearing thresholds. We found that a limited set of variables obtained from both tone-burst and click measurements can accurately predict and categorize hearing loss levels up to a limit of 60 dB HL. We found correct classification scores of pure-tone thresholds between 500 and 4000 Hz up to 100 per cent when using combined click and tone-burst otoacoustic measurements. Prediction of pure-tone thresholds was correct with a maximum estimation error of 10 dB for audiometric octave frequencies between 500 and 4000 Hz. Measurements of multiple tone-bursts OAEs have a significant clinical advantage over the use of clicks alone for clinical applications, and a good classification and prediction of pure-tone thresholds with otoacoustic emissions is possible.
Transient Analysis of Large Scale PV Systems with Floating DC Section
Directory of Open Access Journals (Sweden)
George C. Lazaroiu
2012-09-01
Full Text Available The increasing penetration of renewable sources with power-electronic interfaces in power systems is raising technical problems and the overall efficiency of photovoltaic systems can decrease dramatically. In this context, the optimal layout for the photovoltaic system is required. The most adequate strategy to connect the renewable system to the electrical power grid or to supply the end users must be adopted. The present paper proposes a design layout of a PV plant using a DC bus system to improve the overall energy conversion efficiency. An analysis of steady-state system stability, voltage drop and DC cable conduction losses is conducted. The leakage currents to the ground are investigated through simulations. Experimental results are shown focused on the analysis of optimal layout of photovoltaic systems under particular operating conditions.
Plant databases and data analysis tools
It is anticipated that the coming years will see the generation of large datasets including diagnostic markers in several plant species with emphasis on crop plants. To use these datasets effectively in any plant breeding program, it is essential to have the information available via public database...
Masuzawa, Toru; Ohta, Akiko; Tanaka, Nobuatu; Qian, Yi; Tsukiya, Tomonori
2009-01-01
The effect of the hydraulic force on magnetically levitated (maglev) pumps should be studied carefully to improve the suspension performance and the reliability of the pumps. A maglev centrifugal pump, developed at Ibaraki University, was modeled with 926 376 hexahedral elements for computational fluid dynamics (CFD) analyses. The pump has a fully open six-vane impeller with a diameter of 72.5 mm. A self-bearing motor suspends the impeller in the radial direction. The maximum pressure head and flow rate were 250 mmHg and 14 l/min, respectively. First, a steady-state analysis was performed using commercial code STAR-CD to confirm the model's suitability by comparing the results with the real pump performance. Second, transient analysis was performed to estimate the hydraulic force on the levitated impeller. The impeller was rotated in steps of 1 degrees using a sliding mesh. The force around the impeller was integrated at every step. The transient analysis revealed that the direction of the radial force changed dynamically as the vane's position changed relative to the outlet port during one circulation, and the magnitude of this force was about 1 N. The current maglev pump has sufficient performance to counteract this hydraulic force. Transient CFD analysis is not only useful for observing dynamic flow conditions in a centrifugal pump but is also effective for obtaining information about the levitation dynamics of a maglev pump.
4C code analysis of thermal-hydraulic transients in the KSTAR PF1 superconducting coil
Savoldi Richard, L.; Bonifetto, R.; Chu, Y.; Kholia, A.; Park, S. H.; Lee, H. J.; Zanino, R.
2013-01-01
The KSTAR tokamak, in operation since 2008 at the National Fusion Research Institute in Korea, is equipped with a full superconducting magnet system including the central solenoid (CS), which is made of four symmetric pairs of coils PF1L/U-PF4L/U. Each of the CS coils is pancake wound using Nb3Sn cable-in-conduit conductors with a square Incoloy jacket. The coils are cooled with supercritical He in forced circulation at nominal 4.5 K and 5.5 bar inlet conditions. During different test campaigns the measured temperature increase due to AC losses turned out to be higher than expected, which motivates the present study. The 4C code, already validated against and applied to different types of thermal-hydraulic transients in different superconducting coils, is applied here to the thermal-hydraulic analysis of a full set of trapezoidal current pulses in the PF1 coils, with different ramp rates. We find the value of the coupling time constant nτ that best fits, at each current ramp rate, the temperature increase up to the end of the heating at the coil outlet. The agreement between computed results and the whole set of measured data, including temperatures, pressures and mass flow rates, is then shown to be very good both at the inlet and at the outlet of the coil. The nτ values needed to explain the experimental results decrease at increasing current ramp rates, consistently with the results found in the literature.
Anticipated Transient Without SCRAM(ATWS) analysis using the RETRAN code
Energy Technology Data Exchange (ETDEWEB)
Youn, Bum soo; Lee, Jong beom; Song, Dong soo; Ha, Sang jun [KHNP-CRI, Daejeon (Korea, Republic of)
2014-10-15
The purpose of this study is to evaluate the Anticipated Transient Without Scram(ATWS) Loss of Load(LOL) and Loss of Normal Feedwater(LOFW) events for the OPR1000 reactor. The analysis calculates the peak RCS and secondary system pressure for the LOL and LOFW ATWS events. The main product of this study is the ATWS evaluation of the OPR1000 reactor LOL and LOFW events. The results include a sequence of events and plots of key output parameters.. This study includes results of Loss of Load and Loss of Feedwater ATWS. The LOL case results in a faster reactor trip than the LOFW since the LOFW does not have the turbine trip at time zero. In addition the LOFW event has the SBCS available and as secondary pressure increase, the steam releases from the SBCS valves provide extra cooling to the secondary system, which also cools the primary system. This additional cooling also delays the DSS trip. For the LOFW event, both the turbine and SBCS are providing additional cooling, hence the primary and secondary system heatups are slower and lower. Thus the RCS and steam generator pressure are higher for the LOL event than the LOFW event. The LOL also has a slower decrease in SG water level than the LOFW event. This is due to loss of condenser vacuum that trips and isolates the turbine and renders the SBCS unavailable for the LOL event. Hence the secondary cooling for the LOL event is due to the steam releases from the MSSVs; whereas the LOFW turbine remains online until a DTT occurs on the DSS. Also the SBCS is available because the condenser is available.
García, Irene; Rosas, Tábata; Bejarano, Eduardo R.; Gotor, Cecilia; Romero, Luis C.
2013-01-01
Cyanide is produced concomitantly with ethylene biosynthesis. Arabidopsis (Arabidopsis thaliana) detoxifies cyanide primarily through the enzyme β-cyanoalanine synthase, mainly by the mitochondrial CYS-C1. CYS-C1 loss of function is not toxic for the plant and leads to an increased level of cyanide in cys-c1 mutants as well as a root hairless phenotype. The classification of genes differentially expressed in cys-c1 and wild-type plants reveals that the high endogenous cyanide content of the cys-c1 mutant is correlated with the biotic stress response. Cyanide accumulation and CYS-C1 gene expression are negatively correlated during compatible and incompatible plant-bacteria interactions. In addition, cys-c1 plants present an increased susceptibility to the necrotrophic fungus Botrytis cinerea and an increased tolerance to the biotrophic Pseudomonas syringae pv tomato DC3000 bacterium and Beet curly top virus. The cys-c1 mutation produces a reduction in respiration rate in leaves, an accumulation of reactive oxygen species, and an induction of the alternative oxidase AOX1a and pathogenesis-related PR1 expression. We hypothesize that cyanide, which is transiently accumulated during avirulent bacterial infection and constitutively accumulated in the cys-c1 mutant, uncouples the respiratory electron chain dependent on the cytochrome c oxidase, and this uncoupling induces the alternative oxidase activity and the accumulation of reactive oxygen species, which act by stimulating the salicylic acid-dependent signaling pathway of the plant immune system. PMID:23784464
Analysis of Current Redistribution in a CICC under Transient Heat Pulses
Bottura, L; Marinucci, C
2004-01-01
We have performed experiments and simulations of the current distribution process in a CICC with the aim to understand better the coupled thermal, hydraulic and electric process that leads to a stable or unstable transient cable behaviour. The cable, wound from 128 Nb3Sn and pure copper strands, has been tested in the SULTAN facility. A resistive heater, glued on the jacket of the conductor, has been used to start the transient, and the response has been monitored with arrays of Hall plates. In this paper we report the results of simulations, especially the computed Hall signals, and compare them to the experimental data. Based on the experimental results and their interpretation we postulate that large temperature gradients must develop in the helium stream in the cable cross sections during the transient heat pulse.
Blade loss transient dynamics analysis, volume 2. Task 2: TETRA 2 user's manual
Black, Gerald; Gallardo, Vincente C.
1986-01-01
This is the user's manual for the TETRA 2 Computer Code, a program developed in the NASA-Lewis Blade Loss Program. TETRA 2 calculates a turbine engine's dynamic structural response from applied stimuli. The calculation options are: (1) transient response; and (2) steady state forced response. Based on the method of modal syntheses, the program allows the use of linear, as well as nonlinear connecting elements. Both transient and steady state options can include: flexible Bladed Disk Module, and Nonlinear Connecting Elements (including deadband, hardening/softening spring). The transient option has the additional capability to calculate response with a squeeze film bearing module. TETRA 2 output is summarized in a plotfile which permits post processing such as FFT or graphical animation with the proper software and computer equipment.
Indian Academy of Sciences (India)
Noemi Cerovska; Hana Hoffmeisterova; Tomas Moravec; Helena Plchova; Jitka Folwarczna; Helena Synkova; Helena Ryslava; Viera Ludvikova; Michal Smahel
2012-03-01
Transient expression of foreign genes based on plant viral vectors is a suitable system for the production of relevant immunogens that can be used for the development of a new generation of vaccines against a variety of infectious diseases. In the present study the epitope derived from HPV-16 L2 minor capsid protein (amino acids 108–120) was expressed from Potato virus X (PVX)-based vector pGR106 as N- or C-terminal fusion with the PVX coat protein (PVX CP) in transgenic Nicotiana benthamiana plants. The fusion protein L2108-120-PVX CP was successfully expressed in plants at a level of 170 mg/kg of fresh leaf tissue. The C-terminal fusion protein PVX CP- L2108-120 was expressed using mutated vector sequence to avoid homologous recombination at a level of 8 mg/kg of fresh leaf tissue. Immunogenicity of L2108-120-PVX CP virus-like particles was tested after immunization of mice by subcutaneous injection or tattoo administration. In animal sera the antibodies against the PVX CP and the L2108-120 epitope were found after both methods of vaccine delivery.
Miroslav M Živković; Aleksandar V Nikolić; Radovan B Slavković; Fatima T Živić
2010-01-01
This paper deals with transient nonlinear heat conduction through the insulation wall of the tank for transportation of liquid aluminum. Tanks designed for this purpose must satisfy certain requirements regarding temperature of loading and unloading, during transport. Basic theoretical equations are presented, which describe the problem of heat conduction finite element (FE) analysis, starting from the differential equation of energy balance, taking into account the initial and boundary condi...
Biswas, Rahul; Burguet-Castell, Jordi; Cannon, Kipp; Clayton, Jessica; Dietz, Alexander; Fotopoulos, Nickolas; Goggin, Lisa M; Keppel, Drew; Pankow, Chris; Price, Larry R; Vaulin, Ruslan
2012-01-01
There is a broad class of astrophysical sources that produce detectable, transient, gravitational waves. Some searches for transient gravitational waves are tailored to known features of these sources. Other searches make few assumptions about the sources. Typically events are observable with multiple search techniques. This work describes how to combine the results of searches that are not independent, treating each search as a classifier for a given event. This will be shown to improve the overall sensitivity to gravitational-wave events while directly addressing the problem of consistent interpretation of multiple trials.
Comparison of simulators for variable-speed wind turbine transient analysis
DEFF Research Database (Denmark)
Seman, S.; Iov, Florin; Niiranen, J.
2006-01-01
This paper presents a comparison of three variable-speed wind turbine simulators used for a 2 MW wind turbine short-term transient behaviour study during a symmetrical network disturbance. The simulator with doubly fed induction generator (DFIG) analytical model, the simulator with a finite element...... method (FEM) DFIG model and the wind turbine simulator with an analytical model of DFIG are compared. The comparison of the simulation results shows the influence of the different modelling approaches on the short-term transient simulation accuracy...
Transient simulation of molten salt central receiver
Doupis, Dimitri; Wang, Chuan; Carcorze-Soto, Jorge; Chen, Yen-Ming; Maggi, Andrea; Losito, Matteo; Clark, Michael
2016-05-01
Alstom is developing concentrated solar power (CSP) utilizing 60/40wt% NaNO3-KNO3 molten salt as the working fluid in a tower receiver for the global renewable energy market. In the CSP power generation cycle, receivers undergo a daily cyclic operation due to the transient nature of solar energy. Development of robust and efficient start-up and shut-down procedures is critical to avoiding component failures due to mechanical fatigue resulting from thermal transients, thus maintaining the performance and availability of the CSP plant. The Molten Salt Central Receiver (MSCR) is subject to thermal transients during normal daily operation, a cycle that includes warmup, filling, operation, draining, and shutdown. This paper describes a study to leverage dynamic simulation and finite element analysis (FEA) in development of start-up, shutdown, and transient operation concepts for the MSCR. The results of the FEA also verify the robustness of the MSCR design to the thermal transients anticipated during the operation of the plant.
Directory of Open Access Journals (Sweden)
K.N. Nwaigwe
2012-08-01
Full Text Available A study aimed at a Transient analysis and performance prediction of passive cooling of a building using long wave nocturnal radiation in Owerri, Nigeria are presented. The system modeled consists of the room of a building with a radiator panel attached to its roof, water storage tank located inside the room, pump to circulate water through the radiator panel at night and through a heat exchanger in the room during the day. The mathematical model is based on the thermal radiation properties of the local atmosphere, the heat exchange equations of the radiator panel with the sky during the night and the equations incorporating the relevant heat transfers within the space to be cooled during the day. The resulting equations were transformed into explicit finite difference forms for easy implementation on a personal computer in MATLAB language. This numerical model permits the evaluation of the rate of heat removal from the water storage tank through the radiator panel surface area, Qwt,out, temperature depression between the ambient and room temperatures (Tamb-Trm and total heat gained by water in the storage tank from the space to be cooled through the action of the convector during the day, Qwt,in. The resulting rate of heat removal from the radiator gave a value of 57.6 W/m2, temperature depression was predicted to within 1-1.5ºC and the rate of heat gain by the storage water was 60 W/m2. A sensitivity analysis of the system parameters to ±25% of the base case input values was carried out and the results given as a percentage variation of the above system performance parameters showed consistency to the base case results. An optimal scheme for the modeled 3.0×3.0×2.5 m3 room showed a radiator area of 18.2 m2, a convector area of 28.62 m2 and a tank volume of 1.57 m3. These results show that passive nocturnal cooling technique is a promising solution to the cooling needs for preservation of food and other agricultural produce. It is also
DEFF Research Database (Denmark)
Wagner, Manfred H.; Rolon-Garrido, Victor H.; Nielsen, Jens Kromann
2008-01-01
The transient and steady-state elongational viscosity data of three bidisperse polystyrene blends were investigated recently by Nielsen et al. [J. Rheol. 50, 453-476 (2006)]. The blends contain a monodisperse high molar mass component (M-L= 390 kg/ mol) in a matrix of a monodisperse small molar m...
Transient Stability Analysis of Grid-connected Wind Turbines with Time Domain Simulation
Directory of Open Access Journals (Sweden)
Shuaibing Li
2013-07-01
Full Text Available With an ever-increasing pentration of wind power into power system, the influence to overall system behavior and stability becomes obviously. Therefore, it is so necessary to require wind turbines have good grid adaptability. This paper investigates the effect of directly grid-connected front-end speed controlled wind turbines (FSCWT on transient stability of power system.For this purpose, a voltage based synchronous generator model is used and the drive train model with WinDriver is built. By using a fast excitation control of FSCWT exciter, the FSCWT wind turbines can successfully ride through grid fault and have no problem of angular stability when connected to grid. Simulation studies are carried out to demonstrate and compare the transient performance of the IEEE 5-machine 14-bus system with FSCWT replace by double fed induction generators (DFIG during a three phase fault. Results show that a better transient stability performance is achieved with an intergration of FSCWT in comparsion with DFIG, which can even bring some benefits on power system transient performance and stability.
Escherichia coli is a leading cause of bacterial mastitis in dairy cattle. Typically this infection is transient in nature, causing an infection that lasts 2-3 days. However, in a minority of cases, E. coli has been shown to cause a persistent intramammary infection. The mechanisms that allow for...
DEFF Research Database (Denmark)
Li, H.; Zhao, B.; Han, L.
2010-01-01
In order to analyze correctly the effect of different models for induction generators on the transient performances of large wind power generation, Wind turbine driven squirrel cage induction generator (SCIG) models taking into account both main and leakage flux saturation and skin effect were pr...... mechancical disturbance and a grid voltage sag, respectively. Simulation results have shown that the effect of the flux saturation is obvious on the transient behavious of the wind power generator system, especially for a grid voltage sag studies.......In order to analyze correctly the effect of different models for induction generators on the transient performances of large wind power generation, Wind turbine driven squirrel cage induction generator (SCIG) models taking into account both main and leakage flux saturation and skin effect were...... proposed. A two-mass lump equivalent model of a wind turbine shaft system was also used to considering shaft flexibility. The transient behaviors of the wind generator system with the different models were investigated and compared with the software platform Matlab/Simulink, under conditions of a large...
Energy Technology Data Exchange (ETDEWEB)
Peltonen, Joanna
2009-09-15
Analyses of nuclear reactor safety have increasingly required coupling of full three dimensional neutron kinetics (NK) core models with system transient thermal-hydraulics (TH) codes. To produce results 'within a reasonable' computing time, the coupled codes use different spatial description of the reactor core. The TH code uses few, typically 5 to 20 TH channels, which represent the core. The NK code uses explicit node for each fuel assembly. Therefore, a spatial mapping of coarse grid TH and fine grid NK domain is necessary. However, improper mappings may result in loss of valuable information, thus causing inaccurate prediction of safety parameters. The purpose of this thesis is to study the sensitivity of spatial coupling (channel refinement and spatial mapping) and develop recommendations for NK-TH mapping in simulation of safety transients - Control Rod Drop, Turbine Trip, Feedwater Transient combined with stability performance (minimum pump speed of recirculation pumps). The research methodology consists of spatial coupling convergence study, as increasing number of TH channels and different mapping approach the reference case. The reference case consists of one TH channel per one fuel assembly. The comparison of results has been done under steady-state and transient conditions
CIRCUS--A digital computer program for transient analysis of electronic circuits
Moore, W. T.; Steinbert, L. L.
1968-01-01
Computer program simulates the time domain response of an electronic circuit to an arbitrary forcing function. CIRCUS uses a charge-control parameter model to represent each semiconductor device. Given the primary photocurrent, the transient behavior of a circuit in a radiation environment is determined.
Relay Feedback Analysis for Double Integral Plants
Directory of Open Access Journals (Sweden)
Zhen Ye
2011-01-01
Full Text Available Double integral plants under relay feedback are studied. Complete results on the uniqueness of solutions, existence, and stability of the limit cycles are established using the point transformation method. Analytical expressions are also given for determining the amplitude and period of a limit cycle from the plant parameters.
Quantitative Fluorimetric Analysis of Plant Nicotinamide
Institute of Scientific and Technical Information of China (English)
王泽斌; 冯闻铮; 曹竹安; 刘进元
2001-01-01
Fluorimetry was used to measure the amount of nicotinamide in plant samples. The nicotinamide was extracted and purified from plant tissues with ethyl acetate; converted to the fluorescent derivative, N1-methylnicotinamide, by reacting with methyl iodide; and quantified according to its fluorescent strength. The nicotinamide in the leaf tissue of ten kinds of plants was measured, and the results showed that the nicotinamide content for different plants varied from 0. 1 to 3.0 μg/g of fresh leaf weight. In addition, the crossing value of the fluorescent strength and the nicotinamide amount demonstrated that the linear correlation coefficient generally reached 0. 997, with a detectable limit of 0. 02 mg/L and the relative standard deviation of less than 9%. The results suggested that this method of quantifying nicotinamide in plants is useful and beneficial for functional research.
Chow, Chi-Nga; Zheng, Han-Qin; Wu, Nai-Yun; Chien, Chia-Hung; Huang, Hsien-Da; Lee, Tzong-Yi; Chiang-Hsieh, Yi-Fan; Hou, Ping-Fu; Yang, Tien-Yi; Chang, Wen-Chi
2016-01-01
Transcription factors (TFs) are sequence-specific DNA-binding proteins acting as critical regulators of gene expression. The Plant Promoter Analysis Navigator (PlantPAN; http://PlantPAN2.itps.ncku.edu.tw) provides an informative resource for detecting transcription factor binding sites (TFBSs), corresponding TFs, and other important regulatory elements (CpG islands and tandem repeats) in a promoter or a set of plant promoters. Additionally, TFBSs, CpG islands, and tandem repeats in the conserve regions between similar gene promoters are also identified. The current PlantPAN release (version 2.0) contains 16 960 TFs and 1143 TF binding site matrices among 76 plant species. In addition to updating of the annotation information, adding experimentally verified TF matrices, and making improvements in the visualization of transcriptional regulatory networks, several new features and functions are incorporated. These features include: (i) comprehensive curation of TF information (response conditions, target genes, and sequence logos of binding motifs, etc.), (ii) co-expression profiles of TFs and their target genes under various conditions, (iii) protein-protein interactions among TFs and their co-factors, (iv) TF-target networks, and (v) downstream promoter elements. Furthermore, a dynamic transcriptional regulatory network under various conditions is provided in PlantPAN 2.0. The PlantPAN 2.0 is a systematic platform for plant promoter analysis and reconstructing transcriptional regulatory networks.
GenoCAD Plant Grammar to Design Plant Expression Vectors for Promoter Analysis.
Coll, Anna; Wilson, Mandy L; Gruden, Kristina; Peccoud, Jean
2016-01-01
With the rapid advances in prediction tools for discovery of new promoters and their cis-elements, there is a need to improve plant expression methodologies in order to facilitate a high-throughput functional validation of these promoters in planta. The promoter-reporter analysis is an indispensible approach for characterization of plant promoters. It requires the design of complex plant expression vectors, which can be challenging. Here, we describe the use of a plant grammar implemented in GenoCAD that will allow the users to quickly design constructs for promoter analysis experiments but also for other in planta functional studies. The GenoCAD plant grammar includes a library of plant biological parts organized in structural categories to facilitate their use and management and a set of rules that guides the process of assembling these biological parts into large constructs.
Validation of a plant dynamics code for 4S - Test analysis of natural circulation behavior
Energy Technology Data Exchange (ETDEWEB)
Sebe, F.; Horie, H.; Matsumiya, H. [Toshiba Corporation, 8 Shinsugita-Cho, Isogo-Ku, Yokohama, 235-8523 (Japan); Fanning, T. H. [Argonne National Laboratory, 9700 S Cass Ave, Argonne, IL 60439 (United States)
2012-07-01
A plant transient dynamics code for a sodium-cooled fast reactor was developed by Toshiba. The code is used to evaluate the safety performance of Super-Safe, Small, and Simple reactor (4S) for Anticipated Operational Occurrences (AOOs), Design Basis Accident (DBA) and Beyond DBA (BDBA). The code is currently undergoing verification and validation (V and V). As one of the validation, test analysis of the Shutdown Heat Removal Test (SHRT)-17 performed in the Experimental Breeder Reactor (EBR)-II was conducted. The SHRT-17 is protected loss of flow test. The purpose of this validation is to confirm capability of the code to simulate natural circulation behavior of the plant. As a result, good agreements are shown between the analytical results and the measured data which were available from instrumented subassembly. The detailed validation result of the natural circulation behavior is described in this paper. (authors)
Rodriguez Pretelin (1), Abelardo; Nowak (1), Wolfgang
2017-04-01
Well head protection areas (WHPAs) are frequently used as safety measures for drinking water wells, preventing them from being polluted by restricting land use activities in their proximities. Two sources of uncertainty are involved during delineation: 1) uncertainty in aquifer parameters and 2) time-varying groundwater flow scenarios and their own inherent uncertainties. The former has been studied by Enzenhoefer et al (2012 [1] and 2014 [2]) as probabilistic risk version of WHPA delineation. The latter is frequently neglected and replaced by steady-state assumptions; thereby ignoring time-variant flow conditions triggered either by anthropogenic causes or climatic conditions. In this study we analyze the influence of transient flow considerations in WHPA delineation, following annual seasonality behavior; with transiency represented by four transient conditions: (I) regional groundwater flow direction, (II) strength of the regional hydraulic gradient, (III) natural recharge to the groundwater and (IV) pumping rate. Addressing WHPA delineation in transient flow scenarios is computationally expensive. Thus, we develop an efficient method using a dynamic superposition of steady-state flow solutions coupled with a reversed formulation of advective-dispersive transport based on a Lagrangian particle tracking with continuous injection. This analysis results in a time-frequency map of pixel-wise membership to the well catchment. Additional to transient flow conditions, we recognize two sources of uncertainty, inexact knowledge of transient drivers and parameters. The uncertainties are accommodated through Monte Carlo simulation. With the help of a global sensitivity analysis, we investigate the impact of transiency in WHPA solutions. In particular, we evaluate: (1) Among all considered transients, which ones are the most influential. (2) How influential in WHPA delineation is the transience-related uncertainty compared to aquifer parameter uncertainty. Literature [1] R
Institute of Scientific and Technical Information of China (English)
陆道纲; 隋丹婷
2012-01-01
为实现快堆系统分析软件国产化,在已开发的适用于稳态计算的池式快堆系统分析软件SAC-CFR的基础上,进一步开发了系统各部件的瞬态模型、控制系统和保护系统模型、瞬态工况热工水力学的求解逻辑,完成瞬态计算功能的开发.通过对日本文殊快堆45％功率汽机跳闸工况进行建模分析,验证了SAC-CFR用于系统瞬态分析的有效性,为进一步开发非能动余热排出系统分析模型打下了基础.%Aiming at developing system analysis code independently, the system analysis code for pool-type fast reactor in China (SAC-CFR) under transient operation was developed with further development of component transient model, plant control and protection system model, calculation logic for system transient thermal-hydraulic analysis based on the former SAC-CFR version applicable to steady state analysis. The transient started from turbine trip test at 45 % thermal output in the Monju Plant was analyzed with the developed SAC-CFR. A good agreement between the calculated results and the test data was obtained. SAC-CFR is now ready to incorporate passive residual heat removal model for China Experimental Fast Reactor.
Energy Technology Data Exchange (ETDEWEB)
Roberto, Thiago D., E-mail: thiagodbtr@gmail.com [Instituto de Engenharia Nuclear (IEN/CNEN—RJ), Rua Hélio de Almeida, 75 21941-972, Rio de Janeiro Caixa-Postal: 68550, RJ (Brazil); Silva, Mário A. B. da, E-mail: mabs500@gmail.com [Departamento de Energia Nuclear (CTG/UFPE), Av. Professor Luiz Freire, 1000, Recife 50740-540, PE (Brazil); Lapa, Celso M.F., E-mail: lapa@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN—RJ), Rua Hélio de Almeida, 75 21941-972, Rio de Janeiro Caixa-Postal: 68550, RJ (Brazil)
2016-01-15
The feasibility of performing experiments using water under supercritical conditions is limited by technical and financial difficulties. These difficulties can be overcome by using model fluids that are characterized by feasible supercritical conditions, that is, lower critical pressure and critical temperature. Experimental investigations are normally used to determine the conditions under which model fluids reliably represent supercritical fluids under steady-state conditions. A fluid-to-fluid scaling approach has been proposed to determine the model fluids that represent supercritical fluids in a transient state. Recently, a similar technique known as fractional scaling analysis was developed to establish the conditions under which experiments can be performed using models that represent transients in prototypes. This paper presents a fractional scaling analysis application to determine parameters for a test facility in which transient conditions in supercritical water-cooled reactors are simulated by using carbon dioxide as a model fluid, whose critical point conditions are more feasible than those of water. Similarity is obtained between water (prototype) and carbon dioxide (model) by depressurization in a simple vessel. The main parameters required for the construction of a future test facility are obtained using the proposed method.
Analysis of a Station Black-Out transient in SMR by using the TRACE and RELAP5 code
De Rosa, F.; Lombardo, C.; Mascari, F.; Polidori, M.; Chiovaro, P.; D'Amico, S.; Moscato, I.; Vella, G.
2014-11-01
The present paper deals with the investigation of the evolution and consequences of a Station Black-Out (SBO) initiating event transient in the SPES3 facility [1]. This facility is an integral simulator of a small modular reactor being built at the SIET laboratories, in the framework of the R&D program on nuclear fission funded by the Italian Ministry of Economic Development and led by ENEA. The SBO transient will be simulated by using the RELAP5 and TRACE nodalizations of the SPES3 facility. Moreover, the analysis will contribute to study the differences on the code predictions considering the different modelling approach with one and/or three-dimensional components and to compare the capability of these codes to describe the SPES3 facility behaviour.
Lee, Dongwook; Kim, JongWon
2003-11-01
Streaming media applications over mobile IP networks suffer from playback disruptions resulting from handoff blackout period as well as bandwidth fluctuation. To overcome buffer shortage, pre-buffering technique can be adopted where the client stores sufficient amount of stream in advance. However, under the mobile IP handoff that may take up to several seconds, it is extremely difficult to sustain seamless playback. Inaccurate and conservative choice on the required buffering size can waste limited latency budget, resulting in quality degradation. In this paper, we are extending--from smooth handoff to fast handoff of mobile IPv6--the transient time analysis recently proposed to approximate transient time durations, STP (silent time period) and UTP (unstable time period). The approximated time periods are utilized to estimate the required buffering buffer size accurately. Network simulation result evaluted under simplified buffering strategies shows that the proposed scheme can provide appropriate guideline on the buffer parameters and thus can improve seamless streaming.
Energy Technology Data Exchange (ETDEWEB)
Luna, N. [Secretaria de Energia, Direccion de Operacion Petrolera, Mexico DF (Mexico); Mendez, F. [UNAM, Facultad de Ingenieria, Mexico DF (Mexico); Bautista, O. [ITESM, Division de Ingenieria y Arquitectura, Mexico DF (Mexico)
2005-05-01
We treat numerically in this paper, the transient analysis of a conjugated heat transfer process in the thermal entrance region of a circular tube with a fully developed laminar power-law fluid flow. We apply the quasi-steady approximation for the power-law fluid, identifying the suitable time scales of the process. Thus, the energy equation in the fluids is solved analytically using the well-known integral boundary layer technique. This solution is coupled to the transient energy equation for the solid where the transverse and longitudinal heat conduction effects are taken into account. The numerical results for the temporal evolution of the average temperature of the tube wall, {theta}{sub av,} is plotted for different nondimensional parameters such as conduction parameter, {alpha}, the aspect ratios of the tube, {epsilon} and {epsilon}{sub 0} and the index of power-law fluid, n. (orig.)
Hattiangadi, Ashwin A.
A numerical framework to study multi-physics problem involving coupled thermomechanical analyses for cracks is outlined. Using a thermomechanical cohesive zone model (TM-CZM), load transfer behavior is coupled to heat conduction across a crack. Non-linear effects due to coupling between the mechanical and thermal problem occur through the conductance-separation response between crack faces as well as through the temperature dependence of material constants of the CZM. The TM-CZM is implemented in a convenient framework within the finite element method and applied in the study of: (i) interface crack growth; (ii) crack bridging; and (iii) photo-thermal imaging. Interface fracture in a thermal protection system (TPS) under transient monotonic and cyclic thermal loading is studied using the new TM-CZM and an analytical model. TPS includes an oxidation protection coating (OPC) on a carbon-carbon (C-C) composite substrate. The description of the load transfer behavior uses a traction-separation law with an internal residual property variable that determines the extent of damage caused by mechanical separation. Temperature dependence is incorporated, such that the interfacial strength and therefore the tractions decrease with temperature. The description of thermal transport includes an accurate representation of breakdown of interface conductance with increase in separation. The current state of interface failure, the presence of gas entrapped in the crack as well as radiative heat transfer determines the crack conductance. Coupling between thermal-mechanical analyses affects the interface crack initiation and growth behavior. An analytical model is presented for the uncoupled thermal-mechanical problem to calculate temperature fields and energy release rates. The TM-CZM is also applied in the study of bridged delamination cracks in composite laminates loaded under a temperature gradient. A micromechanism based bridging law is used for load transfer coupled to heat
Directory of Open Access Journals (Sweden)
Sicuranza Giovanni L
2007-01-01
Full Text Available The paper provides an analysis of the transient and the steady-state behavior of a filtered-x partial-error affine projection algorithm suitable for multichannel active noise control. The analysis relies on energy conservation arguments, it does not apply the independence theory nor does it impose any restriction to the signal distributions. The paper shows that the partial-error filtered-x affine projection algorithm in presence of stationary input signals converges to a cyclostationary process, that is, the mean value of the coefficient vector, the mean-square error and the mean-square deviation tend to periodic functions of the sample time.
De Petrocellis, Luciano; Di Marzo, Vincenzo
2010-03-01
The molecular mechanism of action of Delta(9)-tetrahydrocannabinol (THC), the psychotropic constituent of Cannabis, has been a puzzle during the three decades separating its characterization, in 1964, and the cloning, in the 1990s, of cannabinoid CB1 and CB2 receptors. However, while these latter proteins do mediate most of the pharmacological actions of THC, they do not seem to act as receptors for other plant cannabinoids (phytocannabinoids), nor are they the unique targets of the endogenous lipids that were originally identified in animals as agonists of CB1 and CB2 receptors, and named endocannabinoids. Over the last decade, several potential alternative receptors for phytocannabinoids, endocannabinoids, and even synthetic cannabimimetics, have been proposed, often based uniquely on pharmacological evidence obtained in vitro. In particular, the endocannabinoid anandamide, and the other most abundant Cannabis constituent, cannabidiol, seem to be the most "promiscuous" of these compounds. In this article, we review the latest data on the non-CB1, non-CB2 receptors suggested so far for endocannabinoids and plant or synthetic cannabinoids, and lay special emphasis on uncharacterized or orphan G-protein-coupled receptors as well as on transient receptor potential channels.
Exergy analysis of a MSF distillation plant
Energy Technology Data Exchange (ETDEWEB)
Kahraman, Nafiz [Department of Mechanical Engineering, Erciyes University, Kayseri (Turkey)]. E-mail: nafiz@erciyes.edu.tr; Cengel, Yunus A. [Department of Mechanical Engineering/312, University of Nevada, Reno, NV 89557 (United States)
2005-09-15
In this paper, a large MSF distillation plant in the gulf area is analyzed thermodynamically using actual plant operation data. Exergy flow rates are evaluated throughout the plant, and the exergy flow diagram is prepared. The rates of exergy destruction and their percentages are indicated on the diagram so that the locations of highest exergy destruction can easily be identified. The highest exergy destruction (77.7%) occurs within the MSF unit, as expected, and this can be reduced by increasing the number of flashing stages. The exergy destruction in the pumps and motors account for 5.3% of the total, and this also can be reduced by using high efficiency motors and pumps. The plant is determined to have a second law efficiency of just 4.2%, which is very low. This indicates that there are major opportunities in the plant to reduce exergy destruction and, thus, the amount of electric and thermal energy supplied, making the operation of the plant more cost effective.
Transient Analysis of Pressurization and Pneumatic Subsystems of the X-34 Main Propulsion System
Hedayat, A.; Knight, K. C.; Chamption, R. H., Jr.; Kennedy, Jim W. (Technical Monitor)
2000-01-01
Transient models for the pressurization, vent/relief, and pneumatic subsystems of the X-34 Main Propulsion System are presented and simulation of their operation within prescribed requirements are provided. First, using ROCket Engine Transient Simulation (ROCETS) program, pressurization subsystem operation was simulated and helium requirements and the ullage thermodynamic condition within each propellant tank were calculated. Then, Overpressurization scenarios of propellant tanks and the response of vent/relief valves were evaluated using ROCETS simulation of simultaneous operation of the pressurization and vent/relief subsystems by incorporating the valves data into the model. Finally, the ROCETS simulation of in-flight operation of pneumatic subsystem predicted the overall helium consumption, Inter-Propellant Seal (IPS) purge flowrate and thermodynamic conditions, and Spin Start power.
Analysis of single particle diffusion with transient binding using particle filtering.
Bernstein, Jason; Fricks, John
2016-07-21
Diffusion with transient binding occurs in a variety of biophysical processes, including movement of transmembrane proteins, T cell adhesion, and caging in colloidal fluids. We model diffusion with transient binding as a Brownian particle undergoing Markovian switching between free diffusion when unbound and diffusion in a quadratic potential centered around a binding site when bound. Assuming the binding site is the last position of the particle in the unbound state and Gaussian observational error obscures the true position of the particle, we use particle filtering to predict when the particle is bound and to locate the binding sites. Maximum likelihood estimators of diffusion coefficients, state transition probabilities, and the spring constant in the bound state are computed with a stochastic Expectation-Maximization (EM) algorithm.
Design and analysis of ultra-wideband antennas for transient field excitations
Kotzev, Miroslav; Kreitlow, Matthias; Gronwald, Frank
2016-09-01
This work addresses the design of two ultra-wideband antennas for the application of transient field measurements that are characterized by frequency spectra that typically range from a few MHz to several GHz. The motivation for their design is the excitation of high power transient pulses, such as double exponential or damped sinusoidal pulses, within highly resonant metallic enclosures. The antenna design is based on two independent numerical full-wave solvers and it is aimed to achieve a low return loss over a wide range of frequencies together with a high pulse fidelity. It turns out that antennas of the conical and discone type do achieve satisfactory broadband characteristics while limitations towards low frequencies persist. Also the concept of fidelity factor turns out as advantageous to determine whether the proposed antennas allow transmitting certain broadband pulse forms.
Pulse Localization and Fourier Analysis in the Mathematical Model of Acoustic Transient Field
Directory of Open Access Journals (Sweden)
Lukas Koudela
2016-01-01
Full Text Available The numerical model of a semi-cylindrical acoustic diffuser in planar transient acoustic field is discussed. The finite element method was used for the solution of the model. From the computed waveforms the straight and the reflected pulses were automatically extracted using cross-correlation. The harmonic decomposition was performed on the obtained pulses and the results were plotted in the polar pattern.
Energy Technology Data Exchange (ETDEWEB)
Hanson, J.M.
1984-12-01
The report evaluates previous investigations of the gas permeability of the rock surrounding emplacement holes at the Nevada Test Site. The discussion sets the framework from which the present uncertainty in gas permeability can be overcome. The usefulness of the barometric pressure testing method has been established. Flow models were used to evaluate barometric pressure transients taken at NTS holes U2fe, U19ac and U20ai. 31 refs., 103 figs., 18 tabs. (ACR)
Carrasco, Juan A.
2004-01-01
Rewarded homogeneous continuous-time Markov chain (CTMC) models can be used to analyze performance, dependability and performability attributes of computer and telecommunication systems. In this paper, we consider rewarded CTMC models with a reward structure including reward rates associated with states and two measures summarizing the behavior in time of the resulting reward rate random variable: the expected transient reward rate at time t and the expected averaged reward rate in the tim...
Cao, Y.; Faghri, A.
1991-01-01
The performance of a thermal energy storage module is simulated numerically. The change of phase of the phase-change material (PCM) and the transient forced convective heat transfer for the transfer fluid with low Prandtl numbers are solved simultaneously as a conjugate problem. A parametric study and a system optimization are conducted. The numerical results show that module geometry is crucial to the design of a space-based thermal energy storage system.
2011-10-25
... Pending Pest Risk Analysis; Notice of Availability of Data Sheets for Taxa of Plants for Planting That Are Quarantine Pests or Hosts of Quarantine Pests AGENCY: Animal and Plant Health Inspection Service, USDA... pests and 107 taxa of plants for planting are hosts of 13 quarantine pests and therefore should be...
2013-07-12
... Not Authorized Pending Pest Risk Analysis; Notice of Availability of Data Sheets for Taxa of Plants for Planting That Are Quarantine Pests or Hosts of Quarantine Pests AGENCY: Animal and Plant Health... plants for planting are quarantine pests or hosts of quarantine pests and, therefore, should be added...
Severe accident analysis in a two-loop PWR nuclear power plant with the ASTEC code
Energy Technology Data Exchange (ETDEWEB)
Sadek, Sinisa; Amizic, Milan; Grgic, Davor [Zagreb Univ. (Croatia). Faculty of Electrical Engineering and Computing
2013-12-15
The ASTEC/V2.0 computer code was used to simulate a hypothetical severe accident sequence in the nuclear power plant Krsko, a 2-loop pressurized water reactor (PWR) plant. ASTEC is an integral code jointly developed by Institut de Radioprotection et de Surete Nucleaire (IRSN, France) and Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS, Germany) to assess nuclear power plant behaviour during a severe accident. The analysis was conducted in 2 steps. First, the steady state calculation was performed in order to confirm the applicability of the plant model and to obtain correct initial conditions for the accident analysis. The second step was the calculation of the station blackout accident with a leakage of the primary coolant through degraded reactor coolant pump seals, which was a small LOCA without makeup capability. Two scenarios were analyzed: one with and one without the auxiliary feedwater (AFW). The latter scenario, without the AFW, resulted in earlier core damage. In both cases, the accident ended with a core melt and a reactor pressure vessel failure with significant release of hydrogen. In addition, results of the ASTEC calculation were compared with results of the RELAP5/SCDAPSIM calculation for the same transient scenario. The results comparison showed a good agreement between predictions of those 2 codes. (orig.)
Directory of Open Access Journals (Sweden)
Paulo Antonio Delgado-Arredondo
2015-01-01
Full Text Available Induction motors are critical components for most industries and the condition monitoring has become necessary to detect faults. There are several techniques for fault diagnosis of induction motors and analyzing the startup transient vibration signals is not as widely used as other techniques like motor current signature analysis. Vibration analysis gives a fault diagnosis focused on the location of spectral components associated with faults. Therefore, this paper presents a comparative study of different time-frequency analysis methodologies that can be used for detecting faults in induction motors analyzing vibration signals during the startup transient. The studied methodologies are the time-frequency distribution of Gabor (TFDG, the time-frequency Morlet scalogram (TFMS, multiple signal classification (MUSIC, and fast Fourier transform (FFT. The analyzed vibration signals are one broken rotor bar, two broken bars, unbalance, and bearing defects. The obtained results have shown the feasibility of detecting faults in induction motors using the time-frequency spectral analysis applied to vibration signals, and the proposed methodology is applicable when it does not have current signals and only has vibration signals. Also, the methodology has applications in motors that are not fed directly to the supply line, in such cases the analysis of current signals is not recommended due to poor current signal quality.
Temporal frequency probing for 5D transient analysis of global light transport
O'Toole, Matthew
2014-07-27
We analyze light propagation in an unknown scene using projectors and cameras that operate at transient timescales. In this new photography regime, the projector emits a spatio-temporal 3D signal and the camera receives a transformed version of it, determined by the set of all light transport paths through the scene and the time delays they induce. The underlying 3D-to-3D transformation encodes scene geometry and global transport in great detail, but individual transport components (e.g., direct reflections, inter-reflections, caustics, etc.) are coupled nontrivially in both space and time. To overcome this complexity, we observe that transient light transport is always separable in the temporal frequency domain. This makes it possible to analyze transient transport one temporal frequency at a time by trivially adapting techniques from conventional projector-to-camera transport. We use this idea in a prototype that offers three never-seen-before abilities: (1) acquiring time-of-flight depth images that are robust to general indirect transport, such as interreflections and caustics; (2) distinguishing between direct views of objects and their mirror reflection; and (3) using a photonic mixer device to capture sharp, evolving wavefronts of "light-in-flight".
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.
Directory of Open Access Journals (Sweden)
Qinglei Jiang
2011-01-01
Full Text Available The current paper studies the influence of annular seal flow on the transient response of centrifugal pump rotors during the start-up period. A single rotor system and three states of annular seal flow were modeled. These models were solved using numerical integration and finite difference methods. A fluid-structure interaction method was developed. In each time step one of the three annular seal models was chosen to simulate the annular seal flow according to the state of rotor systems. The objective was to obtain a transient response of rotor systems under the influence of fluid-induced forces generated by annular seal flow. This method overcomes some shortcomings of the traditional FSI method by improving the data transfer process between two domains. Calculated results were in good agreement with the experimental results. The annular seal was shown to have a supportive effect on rotor systems. Furthermore, decreasing the seal clearance would enhance this supportive effect. In the transient process, vibration amplitude and critical speed largely changed when the acceleration of the rotor system increased.
Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance
Rasly, Mahmoud; Lin, Zhichao; Yamamoto, Masafumi; Uemura, Tetsuya
2016-05-01
As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.
Analysis of the transient response of nuclear spins in GaAs with/without nuclear magnetic resonance
Directory of Open Access Journals (Sweden)
Mahmoud Rasly
2016-05-01
Full Text Available As an alternative to studying the steady-state responses of nuclear spins in solid state systems, working within a transient-state framework can reveal interesting phenomena. The response of nuclear spins in GaAs to a changing magnetic field was analyzed based on the time evolution of nuclear spin temperature. Simulation results well reproduced our experimental results for the transient oblique Hanle signals observed in an all-electrical spin injection device. The analysis showed that the so called dynamic nuclear polarization can be treated as a cooling tool for the nuclear spins: It works as a provider to exchange spin angular momentum between polarized electron spins and nuclear spins through the hyperfine interaction, leading to an increase in the nuclear polarization. In addition, a time-delay of the nuclear spin temperature with a fast sweep of the external magnetic field produces a possible transient state for the nuclear spin polarization. On the other hand, the nuclear magnetic resonance acts as a heating tool for a nuclear spin system. This causes the nuclear spin temperature to jump to infinity: i.e., the average nuclear spins along with the nuclear field vanish at resonant fields of 75As, 69Ga and 71Ga, showing an interesting step-dip structure in the oblique Hanle signals. These analyses provide a quantitative understanding of nuclear spin dynamics in semiconductors for application in future computation processing.
TAPINS: A THERMAL-HYDRAULIC SYSTEM CODE FOR TRANSIENT ANALYSIS OF A FULLY-PASSIVE INTEGRAL PWR
Directory of Open Access Journals (Sweden)
YEON-GUN LEE
2013-08-01
Full Text Available REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility. Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.
Directory of Open Access Journals (Sweden)
Miroslav M Živković
2010-01-01
Full Text Available This paper deals with transient nonlinear heat conduction through the insulation wall of the tank for transportation of liquid aluminum. Tanks designed for this purpose must satisfy certain requirements regarding temperature of loading and unloading, during transport. Basic theoretical equations are presented, which describe the problem of heat conduction finite element (FE analysis, starting from the differential equation of energy balance, taking into account the initial and boundary conditions of the problem. General 3D problem for heat conduction is considered, from which solutions for two- and one-dimensional heat conduction can be obtained, as special cases. Forming of the finite element matrices using Galerkin method is briefly described. The procedure for solving equations of energy balance is discussed, by methods of resolving iterative processes of nonlinear transient heat conduction. Solution of this problem illustrates possibilities of PAK-T software package, such as materials properties, given as tabular data, or analytical functions. Software also offers the possibility to solve nonlinear and transient problems with incremental methods. Obtained results for different thicknesses of the tank wall insulation materials enable its comparison in regards to given conditions
The rice diacylglycerol kinase family: functional analysis using transient RNA interference
Directory of Open Access Journals (Sweden)
Hongliang eGe
2012-03-01
Full Text Available Diacylglycerol kinase (DGK is a pivotal enzyme that phosphorylates diacylglycerol (DAG to form phosphatidic acid (PA. The production of PA from phospholipase D (PLD and the coupled phospholipase C (PLC/DGK route is an important signaling process in animal and plant cells. In this study, we report a genomic analysis of eight putative rice DGKs encoded by a gene family (OsDGKs grouped into three clusters. To further investigate the functions of the OsDGKs, a double-stranded RNA (dsRNA-induced RNA silencing method was established. Introduction of in vitro-synthesized dsRNAs corresponding to a unique or conserved region of OsDGKs into rice protoplasts abolished or diminished the expression of individual or multiple OsDGK genes. Suppressing the expression of OsDGKs resulted in a distinct depletion of the transcripts of the defense gene OsNPR1 and the salt-responsive gene OsCIPK15. Our primary results suggest that OsDGKs are involved in the signaling of stress responses.
Sahoo, Dipak Kumar; Dey, Nrisingha; Maiti, Indu Bhushan
2014-01-01
We have constructed a small and highly efficient binary Ti vector pSiM24 for plant transformation with maximum efficacy. In the pSiM24 vector, the size of the backbone of the early binary vector pKYLXM24 (GenBank Accession No. HM036220; a derivative of pKYLX71) was reduced from 12.8 kb to 7.1 kb. The binary vector pSiM24 is composed of the following genetic elements: left and right T-DNA borders, a modified full-length transcript promoter (M24) of Mirabilis mosaic virus with duplicated enhancer domains, three multiple cloning sites, a 3'rbcsE9 terminator, replication functions for Escherichia coli (ColE1) and Agrobacterium tumefaciens (pRK2-OriV) and the replicase trfA gene, selectable marker genes for kanamycin resistance (nptII) and ampicillin resistance (bla). The pSiM24 plasmid offers a wide selection of cloning sites, high copy numbers in E. coli and a high cloning capacity for easily manipulating different genetic elements. It has been fully tested in transferring transgenes such as green fluorescent protein (GFP) and β-glucuronidase (GUS) both transiently (agro-infiltration, protoplast electroporation and biolistic) and stably in plant systems (Arabidopsis and tobacco) using both agrobacterium-mediated transformation and biolistic procedures. Not only reporter genes, several other introduced genes were also effectively expressed using pSiM24 expression vector. Hence, the pSiM24 vector would be useful for various plant biotechnological applications. In addition, the pSiM24 plasmid can act as a platform for other applications, such as gene expression studies and different promoter expressional analyses.
Directory of Open Access Journals (Sweden)
Dipak Kumar Sahoo
Full Text Available We have constructed a small and highly efficient binary Ti vector pSiM24 for plant transformation with maximum efficacy. In the pSiM24 vector, the size of the backbone of the early binary vector pKYLXM24 (GenBank Accession No. HM036220; a derivative of pKYLX71 was reduced from 12.8 kb to 7.1 kb. The binary vector pSiM24 is composed of the following genetic elements: left and right T-DNA borders, a modified full-length transcript promoter (M24 of Mirabilis mosaic virus with duplicated enhancer domains, three multiple cloning sites, a 3'rbcsE9 terminator, replication functions for Escherichia coli (ColE1 and Agrobacterium tumefaciens (pRK2-OriV and the replicase trfA gene, selectable marker genes for kanamycin resistance (nptII and ampicillin resistance (bla. The pSiM24 plasmid offers a wide selection of cloning sites, high copy numbers in E. coli and a high cloning capacity for easily manipulating different genetic elements. It has been fully tested in transferring transgenes such as green fluorescent protein (GFP and β-glucuronidase (GUS both transiently (agro-infiltration, protoplast electroporation and biolistic and stably in plant systems (Arabidopsis and tobacco using both agrobacterium-mediated transformation and biolistic procedures. Not only reporter genes, several other introduced genes were also effectively expressed using pSiM24 expression vector. Hence, the pSiM24 vector would be useful for various plant biotechnological applications. In addition, the pSiM24 plasmid can act as a platform for other applications, such as gene expression studies and different promoter expressional analyses.
Benefits for Plants in Ant-Plant Protective Mutualisms: A Meta-Analysis
Trager, Matthew D.; Bhotika, Smriti; Hostetler, Jeffrey A.; Andrade, Gilda V.; Rodriguez-Cabal, Mariano A.; McKeon, C. Seabird; Osenberg, Craig W.; Bolker, Benjamin M.
2010-01-01
Costs and benefits for partners in mutualistic interactions can vary greatly, but surprisingly little is known about the factors that drive this variation across systems. We conducted a meta-analysis of ant-plant protective mutualisms to quantify the effects of ant defenders on plant reproductive output, to evaluate if reproductive effects were predicted from reductions in herbivory and to identify characteristics of the plants, ants and environment that explained variation in ant protection. We also compared our approach with two other recent meta-analyses on ant-plant mutualisms, emphasizing differences in our methodology (using a weighted linear mixed effects model) and our focus on plant reproduction rather than herbivore damage. Based on 59 ant and plant species pairs, ant presence increased plant reproductive output by 49% and reduced herbivory by 62%. The effects on herbivory and reproduction within systems were positively correlated, but the slope of this relationship (0.75) indicated that tolerance to foliar herbivory may be a common plant response to absence of ant guards. Furthermore, the relationship between foliar damage and reproduction varied substantially among systems, suggesting that herbivore damage is not a reliable surrogate for fitness consequences of ant protection. Studies that experimentally excluded ants reported a smaller effect of ant protection on plant reproduction than studies that relied upon natural variation in ant presence, suggesting that study methods can affect results in these systems. Of the ecological variables included in our analysis, only plant life history (i.e., annual or perennial) explained variation in the protective benefit of mutualistic ants: presence of ants benefitted reproduction of perennials significantly more than that of annuals. These results contrast with other quantitative reviews of these relationships that did not include plant life history as an explanatory factor and raise several questions to guide
Benefits for plants in ant-plant protective mutualisms: a meta-analysis.
Directory of Open Access Journals (Sweden)
Matthew D Trager
Full Text Available Costs and benefits for partners in mutualistic interactions can vary greatly, but surprisingly little is known about the factors that drive this variation across systems. We conducted a meta-analysis of ant-plant protective mutualisms to quantify the effects of ant defenders on plant reproductive output, to evaluate if reproductive effects were predicted from reductions in herbivory and to identify characteristics of the plants, ants and environment that explained variation in ant protection. We also compared our approach with two other recent meta-analyses on ant-plant mutualisms, emphasizing differences in our methodology (using a weighted linear mixed effects model and our focus on plant reproduction rather than herbivore damage. Based on 59 ant and plant species pairs, ant presence increased plant reproductive output by 49% and reduced herbivory by 62%. The effects on herbivory and reproduction within systems were positively correlated, but the slope of this relationship (0.75 indicated that tolerance to foliar herbivory may be a common plant response to absence of ant guards. Furthermore, the relationship between foliar damage and reproduction varied substantially among systems, suggesting that herbivore damage is not a reliable surrogate for fitness consequences of ant protection. Studies that experimentally excluded ants reported a smaller effect of ant protection on plant reproduction than studies that relied upon natural variation in ant presence, suggesting that study methods can affect results in these systems. Of the ecological variables included in our analysis, only plant life history (i.e., annual or perennial explained variation in the protective benefit of mutualistic ants: presence of ants benefitted reproduction of perennials significantly more than that of annuals. These results contrast with other quantitative reviews of these relationships that did not include plant life history as an explanatory factor and raise several
Directory of Open Access Journals (Sweden)
Fang Liu
2014-05-01
Full Text Available A fault diagnosis strategy based on the wayside acoustic monitoring technique is investigated for locomotive bearing fault diagnosis. Inspired by the transient modeling analysis method based on correlation filtering analysis, a so-called Parametric-Mother-Doppler-Wavelet (PMDW is constructed with six parameters, including a center characteristic frequency and five kinematic model parameters. A Doppler effect eliminator containing a PMDW generator, a correlation filtering analysis module, and a signal resampler is invented to eliminate the Doppler effect embedded in the acoustic signal of the recorded bearing. Through the Doppler effect eliminator, the five kinematic model parameters can be identified based on the signal itself. Then, the signal resampler is applied to eliminate the Doppler effect using the identified parameters. With the ability to detect early bearing faults, the transient model analysis method is employed to detect localized bearing faults after the embedded Doppler effect is eliminated. The effectiveness of the proposed fault diagnosis strategy is verified via simulation studies and applications to diagnose locomotive roller bearing defects.
Liu, Fang; Shen, Changqing; He, Qingbo; Zhang, Ao; Liu, Yongbin; Kong, Fanrang
2014-05-05
A fault diagnosis strategy based on the wayside acoustic monitoring technique is investigated for locomotive bearing fault diagnosis. Inspired by the transient modeling analysis method based on correlation filtering analysis, a so-called Parametric-Mother-Doppler-Wavelet (PMDW) is constructed with six parameters, including a center characteristic frequency and five kinematic model parameters. A Doppler effect eliminator containing a PMDW generator, a correlation filtering analysis module, and a signal resampler is invented to eliminate the Doppler effect embedded in the acoustic signal of the recorded bearing. Through the Doppler effect eliminator, the five kinematic model parameters can be identified based on the signal itself. Then, the signal resampler is applied to eliminate the Doppler effect using the identified parameters. With the ability to detect early bearing faults, the transient model analysis method is employed to detect localized bearing faults after the embedded Doppler effect is eliminated. The effectiveness of the proposed fault diagnosis strategy is verified via simulation studies and applications to diagnose locomotive roller bearing defects.
Nuclear Power Plant Module, NPP-1: Nuclear Power Cost Analysis.
Whitelaw, Robert L.
The purpose of the Nuclear Power Plant Modules, NPP-1, is to determine the total cost of electricity from a nuclear power plant in terms of all the components contributing to cost. The plan of analysis is in five parts: (1) general formulation of the cost equation; (2) capital cost and fixed charges thereon; (3) operational cost for labor,…
Energy Technology Data Exchange (ETDEWEB)
Bae, B. U.; Park, Y. S.; Kim, J. R.; Kang, K. H.; Choi, K. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Sung, H. J. [KEPCO-NF, Daejeon (Korea, Republic of); Hwang, M. J. [E and 2T, Daejeon (Korea, Republic of); Kang, D. H. [SenTECH, Daejeon (Korea, Republic of); Lim, S. G. [KHNP CRI, Daejeon (Korea, Republic of); Jun, S. S. [FNC, Daejeon (Korea, Republic of)
2015-10-15
Participants of DSP-03 were divided in three groups and each group has focused on the specific subject related to the enhancement of the code analysis. The group A tried to investigate scaling capability of ATLAS test data by comparing to the code analysis for a prototype, and the group C studied to investigate effect of various models in the one-dimensional codes. This paper briefly summarizes the code analysis result from the group B participants in the DSP-03 of the ATLAS test facility. The code analysis by Group B focuses highly on investigating the multi-dimensional thermal hydraulic phenomena in the ATLAS facility during the SLB transient. Even though the one-dimensional system analysis code cannot simulate the whole system of the ATLAS facility with a nodalization of the CFD (Computational Fluid Dynamics) scale, a reactor pressure vessel can be considered with multi-dimensional components to reflect the thermal mixing phenomena inside a downcomer and a core. Also, the CFD could give useful information for understanding complex phenomena in specific components such as the reactor pressure vessel. From the analysis activity of Group B in ATLAS DSP-03, participants adopted a multi-dimensional approach to the code analysis for the SLB transient in the ATLAS test facility. The main purpose of the analysis was to investigate prediction capability of multi-dimensional analysis tools for the SLB experiment result. In particular, the asymmetric cooling and thermal mixing phenomena in the reactor pressure vessel could be significantly focused for modeling the multi-dimensional components.
Development of transient initiating event frequencies for use in probabilistic risk assessments
Energy Technology Data Exchange (ETDEWEB)
Mackowiak, D.P.; Gentillon, C.D.; Smith, K.L.
1985-05-01
Transient initiating event frequencies are an essential input to the analysis process of a nuclear power plant probabilistic risk assessment. These frequencies describe events causing or requiring scrams. This report documents an effort to validate and update from other sources a computer-based data file developed by the Electric Power Research Institute (EPRI) describing such events at 52 United States commercial nuclear power plants. Operating information from the United States Nuclear Regulatory Commission on 24 additional plants from their date of commercial operation has been combined with the EPRI data, and the entire data base has been updated to add 1980 through 1983 events for all 76 plants. The validity of the EPRI data and data analysis methodology and the adequacy of the EPRI transient categories are examined. New transient initiating event frequencies are derived from the expanded data base using the EPRI transient categories and data display methods. Upper bounds for these frequencies are also provided. Additional analyses explore changes in the dominant transients, changes in transient outage times and their impact on plant operation, and the effects of power level and scheduled scrams on transient event frequencies. A more rigorous data analysis methodology is developed to encourage further refinement of the transient initiating event frequencies derived herein. Updating the transient event data base resulted in approx.2400 events being added to EPRI's approx.3000-event data file. The resulting frequency estimates were in most cases lower than those reported by EPRI, but no significant order-of-magnitude changes were noted. The average number of transients per year for the combined data base is 8.5 for pressurized water reactors and 7.4 for boiling water reactors.
Energy Technology Data Exchange (ETDEWEB)
Zheng, Xiaoqing; Cheng, Zeng [Department of Electrical and Computer Engineering, McMaster University (Canada); Deen, M. Jamal, E-mail: jamal@mcmaster.ca [Department of Electrical and Computer Engineering, McMaster University (Canada); School of Biomedical Engineering, McMaster University (Canada); Peng, Hao, E-mail: penghao@mcmaster.ca [Department of Electrical and Computer Engineering, McMaster University (Canada); School of Biomedical Engineering, McMaster University (Canada); Department of Medical Physics, McMaster University, Ontario L8S 4K1, Hamilton (Canada)
2016-02-01
Cadmium Zinc Telluride (CZT) semiconductor detectors are capable of providing superior energy resolution and three-dimensional position information of gamma ray interactions in a large variety of fields, including nuclear physics, gamma-ray imaging and nuclear medicine. Some dedicated Positron Emission Tomography (PET) systems, for example, for breast cancer detection, require higher contrast recovery and more accurate event location compared with a whole-body PET system. The spatial resolution is currently limited by electrode pitch in CZT detectors. A straightforward approach to increase the spatial resolution is by decreasing the detector electrode pitch, but this leads to higher fabrication cost and a larger number of readout channels. In addition, inter-electrode charge spreading can negate any improvement in spatial resolution. In this work, we studied the feasibility of achieving sub-pitch spatial resolution in CZT detectors using two methods: charge sharing effect and transient signal analysis. We noted that their valid ranges of usage were complementary. The dependences of their corresponding valid ranges on electrode design, depth-of-interaction (DOI), voltage bias and signal triggering threshold were investigated. The implementation of these two methods in both pixelated and cross-strip configuration of CZT detectors were discussed. Our results show that the valid range of charge sharing effect increases as a function of DOI, but decreases with increasing gap width and bias voltage. For a CZT detector of 5 mm thickness, 100 µm gap and biased at 400 V, the valid range of charge sharing effect was found to be about 112.3 µm around the gap center. This result complements the valid range of the transient signal analysis within one electrode pitch. For a signal-to-noise ratio (SNR) of ~17 and preliminary measurements, the sub-pitch spatial resolution is expected to be ~30 µm and ~250 µm for the charge sharing and transient signal analysis methods
Zheng, Xiaoqing; Cheng, Zeng; Deen, M. Jamal; Peng, Hao
2016-02-01
Cadmium Zinc Telluride (CZT) semiconductor detectors are capable of providing superior energy resolution and three-dimensional position information of gamma ray interactions in a large variety of fields, including nuclear physics, gamma-ray imaging and nuclear medicine. Some dedicated Positron Emission Tomography (PET) systems, for example, for breast cancer detection, require higher contrast recovery and more accurate event location compared with a whole-body PET system. The spatial resolution is currently limited by electrode pitch in CZT detectors. A straightforward approach to increase the spatial resolution is by decreasing the detector electrode pitch, but this leads to higher fabrication cost and a larger number of readout channels. In addition, inter-electrode charge spreading can negate any improvement in spatial resolution. In this work, we studied the feasibility of achieving sub-pitch spatial resolution in CZT detectors using two methods: charge sharing effect and transient signal analysis. We noted that their valid ranges of usage were complementary. The dependences of their corresponding valid ranges on electrode design, depth-of-interaction (DOI), voltage bias and signal triggering threshold were investigated. The implementation of these two methods in both pixelated and cross-strip configuration of CZT detectors were discussed. Our results show that the valid range of charge sharing effect increases as a function of DOI, but decreases with increasing gap width and bias voltage. For a CZT detector of 5 mm thickness, 100 μm gap and biased at 400 V, the valid range of charge sharing effect was found to be about 112.3 μm around the gap center. This result complements the valid range of the transient signal analysis within one electrode pitch. For a signal-to-noise ratio (SNR) of ~17 and preliminary measurements, the sub-pitch spatial resolution is expected to be ~30 μm and ~250 μm for the charge sharing and transient signal analysis methods
Transient Side Load Analysis of Out-of-Round Film-Cooled Nozzle Extensions
Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike
2012-01-01
There was interest in understanding the impact of out-of-round nozzle extension on the nozzle side load during transient startup operations. The out-of-round nozzle extension could be the result of asymmetric internal stresses, deformation induced by previous tests, and asymmetric loads induced by hardware attached to the nozzle. The objective of this study was therefore to computationally investigate the effect of out-of-round nozzle extension on the nozzle side loads during an engine startup transient. The rocket engine studied encompasses a regeneratively cooled chamber and nozzle, along with a film cooled nozzle extension. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and transient inlet boundary flow properties derived from an engine system simulation. Six three-dimensional cases were performed with the out-of-roundness achieved by three different degrees of ovalization, elongated on lateral y and z axes: one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation line jump was the primary source of the peak side loads. Comparing to the peak side load of the perfectly round nozzle, the peak side loads increased for the slightly and more ovalized nozzle extensions, and either increased or decreased for the two significantly ovalized nozzle extensions. A theory based on the counteraction of the flow destabilizing effect of an exacerbated asymmetrical flow caused by a lower degree of ovalization, and the flow stabilizing effect of a more symmetrical flow, created also by ovalization, is presented to explain the observations obtained in this effort.
Transient Three-Dimensional Side Load Analysis of Out-of-Round Film Cooled Nozzles
Wang, Ten-See; Lin, Jeff; Ruf, Joe; Guidos, Mike
2010-01-01
The objective of this study is to investigate the effect of nozzle out-of-roundness on the transient startup side loads at a high altitude, with an anchored computational methodology. The out-of-roundness could be the result of asymmetric loads induced by hardware attached to the nozzle, asymmetric internal stresses induced by previous tests, and deformation, such as creep, from previous tests. The rocket engine studied encompasses a regeneratively cooled thrust chamber and a film cooled nozzle extension with film coolant distributed from a turbine exhaust manifold. The computational methodology is based on an unstructured-grid, pressure-based computational fluid dynamics formulation, and a transient inlet history based on an engine system simulation. Transient startup computations were performed with the out-of-roundness achieved by four different degrees of ovalization: one perfectly round, one slightly out-of-round, one more out-of-round, and one significantly out-of-round. The results show that the separation-line-jump is the peak side load physics for the round, slightly our-of-round, and more out-of-round cases, and the peak side load increases as the degree of out-of-roundness increases. For the significantly out-of-round nozzle, however, the peak side load reduces to comparable to that of the round nozzle and the separation line jump is not the peak side load physics. The counter-intuitive result of the significantly out-of-round case is found to be related to a side force reduction mechanism that splits the effect of the separation-line-jump into two parts, not only in the circumferential direction and most importantly in time.
Transient analysis of unbalanced short circuits of the ERDA-NASA 100 kW wind turbine alternator
Hwang, H. H.; Gilbert, L. J.
1976-01-01
Unbalanced short-circuit faults on the alternator of the ERDA-NASA Mod-O100-kW experimental wind turbine are studied. For each case, complete solutions for armature, field, and damper-circuit currents; short-circuit torque; and open-phase voltage are derived directly by a mathematical analysis. Formulated results are tabulated. For the Mod-O wind turbine alternator, numerical calculations are given, and results are presented by graphs. Comparisons for significant points among the more important cases are summarized. For these cases the transients are found to be potentially severe. The effect of the alternator neutral-to-ground impedance is evaluated.
Vincent, P.; Buckley, S. M.; Yang, D.; Carle, S. F.
2011-12-01
Anomalous uplift is observed at the Lop Nor, China nuclear test site using ERS satellite SAR data. Using an InSAR time-series analysis method, we show that an increase in absolute uplift with time is observed between 1997 and 1999. The signal is collocated with past underground nuclear tests. Due to the collocation in space with past underground tests we postulate a nuclear test-related hydrothermal source for the uplift signal. A possible mechanism is presented that can account for the observed transient uplift and is consistent with documented thermal regimes associated with underground nuclear tests conducted at the Nevada National Security Site (NNSS) (formerly the Nevada Test Site).
Transient Analysis of Grid-Connected Wind Turbines with DFIG After an External Short-Circuit Fault
DEFF Research Database (Denmark)
Sun, Tao; Chen, Zhe; Blaabjerg, Frede
2004-01-01
on transient analysis of variable speed wind turbines with doubly fed induction generator (DFIG) after an external short-circuit fault. A simulation model of a MW-level variable speed wind turbine with DFIG developed in PSCAD/EMTDC is presented, and the control and protection schemes are described in detail......The fast development of wind power generation brings new requirements for wind turbine integration to the network. After the clearance of an external short-circuit fault, the grid-connected wind turbine should restore its normal operation with minimized power losses. This paper concentrates...
Sayed, Sadeed Bin
2016-11-02
An explicit marching on-in-time scheme for analyzing transient electromagnetic wave interactions on ferromagnetic scatterers is described. The proposed method solves a coupled system of time domain magnetic field volume integral and Landau-Lifshitz-Gilbert (LLG) equations. The unknown fluxes and fields are discretized using full and half Schaubert-Wilton-Glisson functions in space and bandlimited temporal interpolation functions in time. The coupled system is cast in the form of an ordinary differential equation and integrated in time using a PE(CE)m type linear multistep method to obtain the unknown expansion coefficients. Numerical results demonstrating the stability and accuracy of the proposed scheme are presented.
Interval analysis of transient temperature field with uncertain-but-bounded parameters
Wang, Chong; Qiu, ZhiPing
2014-10-01
Based on the traditional finite volume method, a new numerical technique is presented for the transient temperature field prediction with interval uncertainties in both the physical parameters and initial/boundary conditions. New stability theory applicable to interval discrete schemes is developed. Interval ranges of the uncertain temperature field can be approximately yielded by two kinds of parameter perturbation methods. Different order Neumann series are adopted to approximate the interval matrix inverse. By comparing the results with traditional Monte Carlo simulation, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed model and methods.
Second-order explicit finite-difference methods for transient-flow analysis
Chaudhry, M. H.; Hussaini, M. Y.
1983-01-01
Three second-order accurate numerical methods - MacCormack's method, Lambda scheme and Gabutti scheme - are introduced to solve the quasi-linear, hyperbolic partial differential equations describing transient flows in closed conduits. The details of these methods and the treatment of boundary conditions are presented and the results computed by using these methods for a typical piping system are compared. It is shown that for the same accuracy, second-order methods require considerably lesser number of computational nodes and computer time as compared to those required by the first-order methods.
D'Isanto, Antonio; Brescia, Massimo; Donalek, Ciro; Longo, Giuseppe; Riccio, Giuseppe; Djorgovski, Stanislav G
2016-01-01
The exploitation of present and future synoptic (multi-band and multi-epoch) surveys requires an extensive use of automatic methods for data processing and data interpretation. In this work, using data extracted from the Catalina Real Time Transient Survey (CRTS), we investigate the classification performance of some well tested methods: Random Forest, MLPQNA (Multi Layer Perceptron with Quasi Newton Algorithm) and K-Nearest Neighbors, paying special attention to the feature selection phase. In order to do so, several classification experiments were performed. Namely: identification of cataclysmic variables, separation between galactic and extra-galactic objects and identification of supernovae.
Transient Thermal Model and Analysis of the Lunar Surface and Regolith for Cryogenic Fluid Storage
Christie, Robert J.; Plachta, David W.; Yasan, Mohammad M.
2008-01-01
A transient thermal model of the lunar surface and regolith was developed along with analytical techniques which will be used to evaluate the storage of cryogenic fluids at equatorial and polar landing sites. The model can provide lunar surface and subsurface temperatures as a function of latitude and time throughout the lunar cycle and season. It also accounts for the presence of or lack of the undisturbed fluff layer on the lunar surface. The model was validated with Apollo 15 and Clementine data and shows good agreement with other analytical models.
Numerical analysis of transient keyhole shape in pulsed current plasma arc welding
Institute of Scientific and Technical Information of China (English)
孙俊华; 武传松
2014-01-01
Based on the characteristics of“one keyhole in a pulse”in pulsed current plasma arc welding (PAW),the transient variation process ofweld pool in a pulse cycle is simulated through the establishment ofcorresponding heat source model.And considering the effects ofgravitational force,plasma arc pressure and surface tension on the weld pool surface,the dynamic change features of the keyhole shape in a pulse cycle are calculated by using surface deformation equation. Experiments are conducted and validate that the calculated weld fusion line is in good agreement with the experimental results.
Polarimetric analysis of mass transfer in the X-ray transient A0538-66
Clayton, Geoffrey C.; Brown, John C.; Thompson, Ian B.; Fox, Geoffrey K.
1989-01-01
Observations of optical polarimetric variations of the recurrent X-ray transient A0538-66 during outbursts 99 and 75 are used to investigate the redistribution of gas in the system during periastron passage. The results are consistent with the polarization arising from light in the primary (Be-star) neighborhood which is scattered off a Be-star type disk and a large gas cloud created near periatron by the neutron star passage. It is suggested that the cloud persists near the periastron direction for longer than the Keplerian rotation time of the inner Be-star disk.
Verification of a neutronic code for transient analysis in reactors with Hex-z geometry
Energy Technology Data Exchange (ETDEWEB)
Gonzalez-Pintor, S.; Verdu, G. [Departamento de Ingenieria Quimica Y Nuclear, Universitat Politecnica de Valencia, Cami de Vera, 14, 46022. Valencia (Spain); Ginestar, D. [Departamento de Matematica Aplicada, Universitat Politecnica de Valencia, Cami de Vera, 14, 46022. Valencia (Spain)
2012-07-01
Due to the geometry of the fuel bundles, to simulate reactors such as VVER reactors it is necessary to develop methods that can deal with hexagonal prisms as basic elements of the spatial discretization. The main features of a code based on a high order finite element method for the spatial discretization of the neutron diffusion equation and an implicit difference method for the time discretization of this equation are presented and the performance of the code is tested solving the first exercise of the AER transient benchmark. The obtained results are compared with the reference results of the benchmark and with the results provided by PARCS code. (authors)
An Analysis of Transient Overvoltages during the Energization of Electric Ship Propulsion Systems.
Brenna, Morris; Foiadelli, Federica; Zaninelli, Dario
2015-01-01
This paper addresses the resonance phenomena that can occur in an isolated distribution system during transient events such as repeated energizations or power converter switching. In particular, the aim of this study is to analyze the energization of an onboard radial distribution system installed on an electric ship and to determine how the various leakage parameters that can cause resonance problems such as high peak overvoltages when the circuit breaker is closed are relevant. The paper presents a detailed model of whole distribution system, which is validated using infield measurements that refer to a real case in which these events damaged the ships transformers, causing it to be removed from duty.
An Analysis of Transient Overvoltages during the Energization of Electric Ship Propulsion Systems
Brenna, Morris; Foiadelli, Federica; Zaninelli, Dario
2015-01-01
This paper addresses the resonance phenomena that can occur in an isolated distribution system during transient events such as repeated energizations or power converter switching. In particular, the aim of this study is to analyze the energization of an onboard radial distribution system installed on an electric ship and to determine how the various leakage parameters that can cause resonance problems such as high peak overvoltages when the circuit breaker is closed are relevant. The paper presents a detailed model of whole distribution system, which is validated using infield measurements that refer to a real case in which these events damaged the ships transformers, causing it to be removed from duty. PMID:26240835
Optimization of High-Resolution Continuous Flow Analysis for Transient Climate Signals in Ice Cores
DEFF Research Database (Denmark)
Bigler, Matthias; Svensson, Anders; Kettner, Ernesto
2011-01-01
meltwater conductivity detection modules. The system is optimized for high- resolution determination of transient signals in thin layers of deep polar ice cores. Based on standard measurements and by comparing sections of early Holocene and glacial ice from Greenland, we find that the new system features...... a depth resolution in the ice of a few millimeters which is considerably better than other CFA systems. Thus, the new system can resolve ice strata down to 10 mm thickness and has the potential of identifying annual layers in both Greenland and Antarctic ice cores throughout the last glacial cycle....
Transient expression assays in tobacco protoplasts.
Vanden Bossche, Robin; Demedts, Brecht; Vanderhaeghen, Rudy; Goossens, Alain
2013-01-01
The sequence information generated through genome and transcriptome analysis from plant tissues has reached unprecedented sizes. Sequence homology-based annotations may provide hints for the possible function and roles of particular plant genes, but the functional annotation remains nonexistent or incomplete for many of them. To discover gene functions, transient expression assays are a valuable tool because they can be done more rapidly and at a higher scale than generating stably transformed tissues. Here, we describe a transient expression assay in protoplasts derived from suspension cells of tobacco (Nicotiana tabacum) for the study of the transactivation capacities of transcription factors. To enhance throughput and reproducibility, this method can be automated, allowing medium-throughput screening of interactions between large compendia of potential transcription factors and gene promoters.
Iacomini, Christie; Powers, Aaron; Speight, Garland; Padilla, Sebastian; Paul, Heather L.
2009-01-01
A Metabolic heat-regenerated Temperature Swing Adsorption (MTSA) system is being developed for carbon dioxide, water and thermal control in a lunar and martian portable life support system (PLSS). A previous system analysis was performed to evaluate the impact of MTSA on PLSS design. That effort was Mars specific and assumed liquid carbon dioxide (LCO2) coolant made from martian resources. Transient effects were not considered but rather average conditions were used throughout the analysis. This effort takes into further consideration the transient effects inherent in the cycling MTSA system as well as assesses the use of water as coolant. Standard heat transfer, thermodynamic, and heat exchanger methods are presented to conduct the analysis. Assumptions and model verification are discussed. The tool was used to perform various system studies. Coolant selection was explored and takes into account different operational scenarios as the minimum bed temperature is driven by the sublimation temperature of the coolant (water being significantly higher than LCO2). From this, coolant mass is sized coupled with sorbent bed mass because MTSA adsorption performance decreases with increasing sublimation temperature. Reduction in heat exchanger performance and even removal of certain heat exchangers, like a recuperative one between the two sorbent beds, is also investigated. Finally, the coolant flow rate is varied over the cycle to determine if there is a more optimal means of cooling the bed from a mass perspective. Results of these studies and subsequent recommendations for system design are presented.
Plant phenotyping: from bean weighing to image analysis.
Walter, Achim; Liebisch, Frank; Hund, Andreas
2015-01-01
Plant phenotyping refers to a quantitative description of the plant's anatomical, ontogenetical, physiological and biochemical properties. Today, rapid developments are taking place in the field of non-destructive, image-analysis -based phenotyping that allow for a characterization of plant traits in high-throughput. During the last decade, 'the field of image-based phenotyping has broadened its focus from the initial characterization of single-plant traits in controlled conditions towards 'real-life' applications of robust field techniques in plant plots and canopies. An important component of successful phenotyping approaches is the holistic characterization of plant performance that can be achieved with several methodologies, ranging from multispectral image analyses via thermographical analyses to growth measurements, also taking root phenotypes into account.
Transient current analysis of a GaN radiation detector by TCAD
Energy Technology Data Exchange (ETDEWEB)
Wang, Jinghui; Mulligan, Padhraic L.; Cao, Lei R., E-mail: cao.152@osu.edu
2014-10-11
A gallium nitride (GaN) Schottky diode radiation detector has been fabricated with a successfully demonstrated radiation response to alpha particles and neutrons when using Li as a convertor. In order to understand the charge collection process for further device modification, the Sentaurus TCAD software package is employed to quantitatively study the transient current produced by energetic charge particles. By comparing the simulation and experimental results, especially the capacitance–voltage relationship and charge collection efficiency, the device parameters and physics models used for the simulation are validated. The time behavior of the transient current is studied, and the carrier generation/loss by impact ionization, recombination, and trapping are discussed. The total collected charge contributed by various components, such as drift, funneling, and diffusion are also analyzed. - Highlights: • A TCAD model is established for a GaN Schottky diode radiation detector. • Schottky side mainly collects holes, while ohmic side solely collects electrons. • The funneling region evolution is visualized by carrier current densities. • Carrier generation/loss by impact ionization/trapping is insignificant. • The collected charges are primarily drift carriers in the depletion region.
Transient pressure analysis of fractured well in bi-zonal gas reservoirs
Zhao, Yu-Long; Zhang, Lie-Hui; Liu, Yong-hui; Hu, Shu-Yong; Liu, Qi-Guo
2015-05-01
For hydraulic fractured well, how to evaluate the properties of fracture and formation are always tough jobs and it is very complex to use the conventional method to do that, especially for partially penetrating fractured well. Although the source function is a very powerful tool to analyze the transient pressure for complex structure well, the corresponding reports on gas reservoir are rare. In this paper, the continuous point source functions in anisotropic reservoirs are derived on the basis of source function theory, Laplace transform method and Duhamel principle. Application of construction method, the continuous point source functions in bi-zonal gas reservoir with closed upper and lower boundaries are obtained. Sequentially, the physical models and transient pressure solutions are developed for fully and partially penetrating fractured vertical wells in this reservoir. Type curves of dimensionless pseudo-pressure and its derivative as function of dimensionless time are plotted as well by numerical inversion algorithm, and the flow periods and sensitive factors are also analyzed. The source functions and solutions of fractured well have both theoretical and practical application in well test interpretation for such gas reservoirs, especial for the well with stimulated reservoir volume around the well in unconventional gas reservoir by massive hydraulic fracturing which always can be described with the composite model.
LISSAT Analysis of a Generic Centrifuge Enrichment Plant
Energy Technology Data Exchange (ETDEWEB)
Lambert, H; Elayat, H A; O?Connell, W J; Szytel, L; Dreicer, M
2007-05-31
The U.S. Department of Energy (DOE) is interested in developing tools and methods for use in designing and evaluating safeguards systems for current and future plants in the nuclear power fuel cycle. The DOE is engaging several DOE National Laboratories in efforts applied to safeguards for chemical conversion plants and gaseous centrifuge enrichment plants. As part of the development, Lawrence Livermore National Laboratory has developed an integrated safeguards system analysis tool (LISSAT). This tool provides modeling and analysis of facility and safeguards operations, generation of diversion paths, and evaluation of safeguards system effectiveness. The constituent elements of diversion scenarios, including material extraction and concealment measures, are structured using directed graphs (digraphs) and fault trees. Statistical analysis evaluates the effectiveness of measurement verification plans and randomly timed inspections. Time domain simulations analyze significant scenarios, especially those involving alternate time ordering of events or issues of timeliness. Such simulations can provide additional information to the fault tree analysis and can help identify the range of normal operations and, by extension, identify additional plant operational signatures of diversions. LISSAT analyses can be used to compare the diversion-detection probabilities for individual safeguards technologies and to inform overall strategy implementations for present and future plants. Additionally, LISSAT can be the basis for a rigorous cost-effectiveness analysis of safeguards and design options. This paper will describe the results of a LISSAT analysis of a generic centrifuge enrichment plant. The paper will describe the diversion scenarios analyzed and the effectiveness of various safeguards systems alternatives.
Techniques for Analysis of Plant Phenolic Compounds
Roberts, Thomas H.; Meredith A. Wilkes; Ali Khoddami
2013-01-01
Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the pre...
A meta-analysis of local adaptation in plants.
Directory of Open Access Journals (Sweden)
Roosa Leimu
Full Text Available Local adaptation is of fundamental importance in evolutionary, population, conservation, and global-change biology. The generality of local adaptation in plants and whether and how it is influenced by specific species, population and habitat characteristics have, however, not been quantitatively reviewed. Therefore, we examined published data on the outcomes of reciprocal transplant experiments using two approaches. We conducted a meta-analysis to compare the performance of local and foreign plants at all transplant sites. In addition, we analysed frequencies of pairs of plant origin to examine whether local plants perform better than foreign plants at both compared transplant sites. In both approaches, we also examined the effects of population size, and of the habitat and species characteristics that are predicted to affect local adaptation. We show that, overall, local plants performed significantly better than foreign plants at their site of origin: this was found to be the case in 71.0% of the studied sites. However, local plants performed better than foreign plants at both sites of a pair-wise comparison (strict definition of local adaption only in 45.3% of the 1032 compared population pairs. Furthermore, we found local adaptation much more common for large plant populations (>1000 flowering individuals than for small populations (<1000 flowering individuals for which local adaptation was very rare. The degree of local adaptation was independent of plant life history, spatial or temporal habitat heterogeneity, and geographic scale. Our results suggest that local adaptation is less common in plant populations than generally assumed. Moreover, our findings reinforce the fundamental importance of population size for evolutionary theory. The clear role of population size for the ability to evolve local adaptation raises considerable doubt on the ability of small plant populations to cope with changing environments.
Recent developments in fast spectroscopy for plant mineral analysis
Directory of Open Access Journals (Sweden)
Marie evan Maarschalkerweerd
2015-03-01
Full Text Available Ideal fertilizer management to optimize plant productivity and quality is more relevant than ever, as global food demands increase along with the rapidly growing world population. At the same time, sub-optimal or excessive use of fertilizers leads to severe environmental damage in areas of intensive crop production. The approaches of soil and plant mineral analysis are briefly compared and discussed here, and the new techniques using fast spectroscopy that offer cheap, rapid and easy-to-use analysis of plant nutritional status are reviewed. The majority of these methods use vibrational spectroscopy, such as Visual-Near Infrared (Vis-NIR and to a lesser extent Ultraviolet (UV and Mid-Infrared (MIR spectroscopy. Advantages of and problems with application of these techniques are thoroughly discussed. Spectroscopic techniques considered having major potential for plant mineral analysis, such as chlorophyll a fluorescence, X-ray fluorescence (XRF and Laser-Induced Breakdown Spectroscopy (LIBS are also described.
Choi, M H; Park, C H; Kim, S W; Hahn, S H; Seong, D J; Kim, J C
1999-01-01
The thermal diffusivity in a direction perpendicular to an epoxy resin film sandwiched between two identical metal layers was measured not only by using a pulsed transient analysis but also by using AC calorimetry. The pulsed transient analysis utilized the surface-temperature decay of the heating pulse from a Q-switched, 2nd harmonic generated Nd:YAG laser. The temperature decay was measured with a HgCdTe infrared detector. After data collection, a nonlinear least-squares regression was performed to estimate the optimal values of several separate thermal parameters by fitting the data to the solutions. Additionally, the thermal diffusivity of the samples was obtained by using the AC calorimetric method which measured the frequency-dependent phase changes of the samples. The thermal diffusivities obtained by the two methods were in the range of 0.07 approx 0.09 x 10 sup - sup 2 cm sup 2 /s, agreed within 8 %, but were lower than the literature values. To improve the results, the contact heat resistance from t...
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.
Frequency domain analysis of power system transients using Welch and Yule-Walker AR methods
Energy Technology Data Exchange (ETDEWEB)
Alkan, Ahmet [Department of Computer Engineering, Yasar University, 35500 Izmir (Turkey); Yilmaz, Ahmet S. [Department of Electrical and Electronics Engineering, Kahramanmaras Suetcue Imam University, 46050-9 Kahramanmaras (Turkey)
2007-07-15
In this study, power quality (PQ) signals are analyzed by using Welch (non-parametric) and autoregressive (parametric) spectral estimation methods. The parameters of the autoregressive (AR) model were estimated by using the Yule-Walker method. PQ spectra were then used to compare the applied spectral estimation methods in terms of their frequency resolution and the effects in determination of spectral components. The variations in the shape of the obtained power spectra were examined in order to detect power system transients. Performance of the proposed methods was evaluated by means of power spectral densities (PSDs). Graphical results comparing the performance of the AR method with that of the Welch technique are given. The results demonstrate superior performance of the AR method over the Welch method. (author)
Non-modal stability analysis and transient growth in a magnetized Vlasov plasma
Ratushnaya, Valeria
2014-01-01
Collisionless plasmas, such as those encountered in tokamaks, exhibit a rich variety of instabilities. The physical origin, triggering mechanisms and fundamental understanding of many plasma instabilities, however, are still open problems. We investigate the stability properties of a collisionless Vlasov plasma in a stationary homogeneous magnetic field. We narrow the scope of our investigation to the case of Maxwellian plasma. For the first time using a fully kinetic approach we show the emergence of the local instability, a transient growth, followed by classical Landau damping in a stable magnetized plasma. We show that the linearized Vlasov operator is non-normal leading to the algebraic growth of the perturbations using non-modal stability theory. The typical time scales of the obtained instabilities are of the order of several plasma periods. The first-order distribution function and the corresponding electric field are calculated and the dependence on the magnetic field and perturbation parameters is s...
A multiscale physical model for the transient analysis of PEM water electrolyzer anodes.
Oliveira, Luiz Fernando L; Laref, Slimane; Mayousse, Eric; Jallut, Christian; Franco, Alejandro A
2012-08-07
Polymer electrolyte membrane water electrolyzers (PEMWEs) are electrochemical devices that can be used for the production of hydrogen. In a PEMWE the anode is the most complex electrode to study due to the high overpotential of the oxygen evolution reaction (OER), not widely understood. A physical bottom-up multi-scale transient model describing the operation of a PEMWE anode is proposed here. This model includes a detailed description of the elementary OER kinetics in the anode, a description of the non-equilibrium behavior of the nanoscale catalyst-electrolyte interface, and a microstructural-resolved description of the transport of charges and O(2) at the micro and mesoscales along the whole anode. The impact of different catalyst materials on the performance of the PEMWE anode, and a study of sensitivity to the operation conditions are evaluated from numerical simulations and the results are discussed in comparison with experimental data.
Analysis of transient temperature field of the laminate composite membrane in space environment
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The on-orbit transient temperature of reflector laminate film was analyzed by using finite element method (FEM) . Numerical simulation was used by FEM software ANSYS. Results reveal that the temperature levels of the laminate composite membrane alternate greatly in the orbital period, which is about ±80℃. This range exceeds the material's operating temperature level. So it is necessary to put effective thermal control into effect to the laminate composite membrane. There is temperature gradient in the thickness direction of the laminate composite membrane: there is a light change in Kevlar/Epoxy layer. The temperature of the laminate composite membrane is obviously lower than the seam's temperature. Results provide reference to the thermal control of the inflatable reflector with high precision requirement.
Energy Technology Data Exchange (ETDEWEB)
Lee, Jun-Ha; Lee, Hoong-Joo [Sangmyung University, Chonan (Korea, Republic of)
2005-02-15
We developed a new systematic calibration procedure which was applied to the prediction of the diffusivity, the segregation, and transient enhanced diffusion (TED) of an indium impurity. The TED of the indium impurity was studied using four different experimental conditions. Although indium is susceptible to TED, rapid thermal annealing (RTA) is effective in suppressing the TED effect and maintaining a steep retrograde profile. Like boron impurities, the indium shows significant oxidation-enhanced diffusion in silicon and has segregation coefficients much less than 1 at the Si/SiO{sub 2} interface. In contrast to boron, the segregation coefficient of indium decreases as the temperature increases. The accuracy of the proposed procedure was validated by using secondary ion mass spectrometry (SIMS) data and by using the 0.13-{mu}m device characteristics, such as V{sub th} and I{sub dsat}, for which the differences between simulation and experiment less than 5 %.
Busy period analysis, rare events and transient behavior in fluid flow models
Directory of Open Access Journals (Sweden)
Søren Asmussen
1994-01-01
Full Text Available We consider a process {(Jt,Vt}t≥0 on E×[0,∞, such that {Jt} is a Markov process with finite state space E, and {Vt} has a linear drift ri on intervals where Jt=i and reflection at 0. Such a process arises as a fluid flow model of current interest in telecommunications engineering for the purpose of modeling ATM technology. We compute the mean of the busy period and related first passage times, show that the probability of buffer overflow within a busy cycle is approximately exponential, and give conditioned limit theorems for the busy cycle with implications for quick simulation. Further, various inequalities and approximations for transient behavior are given. Also explicit expressions for the Laplace transform of the busy period are found. Mathematically, the key tool is first passage probabilities and exponential change of measure for Markov additive processes.
The MELTSPREAD-1 computer code for the analysis of transient spreading in containments
Energy Technology Data Exchange (ETDEWEB)
Farmer, M.T.; Sienicki, J.J.; Spencer, B.W.
1990-01-01
Transient spreading of molten core materials is important in the assessment of severe-accident sequences for Mk-I boiling water reactors (BWRs). Of interest is whether core materials are able to spread over the pedestal and drywell floors to contact the containment shell and cause thermally induced shell failure, or whether heat transfer to underlying concrete and overlying water will freeze the melt short of the shell. The development of a computational capability for the assessment of this problem was initiated by Sienicki et al. in the form of MELTSPREAD-O code. Development is continuing in the form of the MELTSPREAD-1 code, which contains new models for phenomena that were ignored in the earlier code. This paper summarizes these new models, provides benchmarking calculations of the relocation model against an analytical solution as well as simulant spreading data, and summarizes the results of a scoping calculation for the full Mk-I system.
Transient Torsional Analysis of a Belt Conveyor Drive with Pneumatic Flexible Shaft Coupling
Directory of Open Access Journals (Sweden)
Kaššay Peter
2017-03-01
Full Text Available Development and application of pneumatic flexible shaft couplings have been in the center of our department research activities for a long time. These couplings are able to change torsional stiffness by changing pressure in their flexible elements – air bellows. Until now we have dealt with the use of pneumatic flexible shaft couplings for tuning mechanical systems working with periodically alternating load torque at steady state. Some mechanical systems, however, operate with a static load torque at constant speed (e.g. hoists, elevators, etc., where it is necessary to consider the suitability of shaft coupling in terms of load torque at transient conditions (run-up and braking. Therefore we decided to analyze the use of pneumatic flexible shaft couplings also in this type of mechanical systems on an example of conveyor belt drive.
Institute of Scientific and Technical Information of China (English)
H. P. RANI; G. J. REDDY; C. N. KIM
2013-01-01
The unsteady natural convective couple stress fluid flow over a semi-infinite vertical cylinder is analyzed for the homogeneous first-order chemical reaction effect. The couple stress fluid flow model introduces the length dependent effect based on the material constant and dynamic viscosity. Also, it introduces the biharmonic operator in the Navier-Stokes equations, which is absent in the case of Newtonian fluids. The solution to the time-dependent non-linear and coupled governing equations is carried out with an unconditionally stable Crank-Nicolson type of numerical schemes. Numerical results for the transient flow variables, the average wall shear stress, the Nusselt number, and the Sherwood number are shown graphically for both generative and destructive reactions. The time to reach the temporal maximum increases as the reaction constant K increases. The average values of the wall shear stress and the heat transfer rate decrease as K increases, while increase with the increase in the Sherwood number.
Edwards, C. L. W.; Meissner, F. T.; Hall, J. B.
1979-01-01
Color computer graphics techniques were investigated as a means of rapidly scanning and interpreting large sets of transient heating data. The data presented were generated to support the conceptual design of a heat-sink thermal protection system (TPS) for a hypersonic research airplane. Color-coded vector and raster displays of the numerical geometry used in the heating calculations were employed to analyze skin thicknesses and surface temperatures of the heat-sink TPS under a variety of trajectory flight profiles. Both vector and raster displays proved to be effective means for rapidly identifying heat-sink mass concentrations, regions of high heating, and potentially adverse thermal gradients. The color-coded (raster) surface displays are a very efficient means for displaying surface-temperature and heating histories, and thereby the more stringent design requirements can quickly be identified. The related hardware and software developments required to implement both the vector and the raster displays for this application are also discussed.
Analysis of Fractional Flow for Transient Two-Phase Flow in Fractal Porous Medium
Lu, Ting; Duan, Yonggang; Fang, Quantang; Dai, Xiaolu; Wu, Jinsui
2016-03-01
Prediction of fractional flow in fractal porous medium is important for reservoir engineering and chemical engineering as well as hydrology. A physical conceptual fractional flow model of transient two-phase flow is developed in fractal porous medium based on the fractal characteristics of pore-size distribution and on the approximation that porous medium consist of a bundle of tortuous capillaries. The analytical expression for fractional flow for wetting phase is presented, and the proposed expression is the function of structural parameters (such as tortuosity fractal dimension, pore fractal dimension, maximum and minimum diameters of capillaries) and fluid properties (such as contact angle, viscosity and interfacial tension) in fractal porous medium. The sensitive parameters that influence fractional flow and its derivative are formulated, and their impacts on fractional flow are discussed.
Analysis and Sizing for Transient Thermal Heating of Insulated Aerospace Vehicle Structures
Blosser, Max L.
2012-01-01
An analytical solution was derived for the transient response of an insulated structure subjected to a simplified heat pulse. The solution is solely a function of two nondimensional parameters. Simpler functions of these two parameters were developed to approximate the maximum structural temperature over a wide range of parameter values. Techniques were developed to choose constant, effective thermal properties to represent the relevant temperature and pressure-dependent properties for the insulator and structure. A technique was also developed to map a time-varying surface temperature history to an equivalent square heat pulse. Equations were also developed for the minimum mass required to maintain the inner, unheated surface below a specified temperature. In the course of the derivation, two figures of merit were identified. Required insulation masses calculated using the approximate equation were shown to typically agree with finite element results within 10%-20% over the relevant range of parameters studied.
Simulation Analysis of Transient Earth Voltages Aroused by Partial Discharge in Switchgear
Directory of Open Access Journals (Sweden)
Man Yuyan
2014-01-01
Full Text Available The authors investigated the properties of Transient Earth Voltages (TEV Aroused by Partial Discharge in Switchgear by Simulation. The mechanism of TEV aroused by partial discharge in switchgears is analyzed. The Finite Integration Theory (FIT was employed to simulate the propagation of TEV in the switchgear. The simulation results show that the pulse width of TEV increases as the pulse width of PD pulse increases and the amplitude of TEV is proportional to the PD pulse amplitude. There are time differences between the TEV signals of different detecting points when the TEV propagating on the switchgear’s surface. Based on the simulation, a method of locating the PD of switchgear is proposed by positioning multi-sensors on the external surface of switchgear.
An Analysis of Transient Overvoltages during the Energization of Electric Ship Propulsion Systems
Directory of Open Access Journals (Sweden)
Morris Brenna
2015-01-01
Full Text Available This paper addresses the resonance phenomena that can occur in an isolated distribution system during transient events such as repeated energizations or power converter switching. In particular, the aim of this study is to analyze the energization of an onboard radial distribution system installed on an electric ship and to determine how the various leakage parameters that can cause resonance problems such as high peak overvoltages when the circuit breaker is closed are relevant. The paper presents a detailed model of whole distribution system, which is validated using infield measurements that refer to a real case in which these events damaged the ships transformers, causing it to be removed from duty.
Directory of Open Access Journals (Sweden)
Younsi Ramdane
2015-01-01
Full Text Available In the present paper, three-dimensional equations for coupled heat and mass conservation equations for wood are solved to study the transient heat and mass transfer during high thermal treatment of wood. The model is based on Luikov’s approach, including pressure. The model equations are solved numerically by the commercial package FEMLfor the temperature and moisture content histories under different treatment conditions. The simulation of the proposed conjugate problem allows the assessment of the effect of the heat and mass transfer within wood. A parametric study was also carried out to determine the effects of several parameters such as initial moisture content and the sample thickness on the temperature, pressure and moisture content distributions within the samples during heat treatment.
Modeling and Analysis of Transient Processes in Open Resonant Structures New Methods and Techniques
Sirenko, Yuriy K; Ström, Staffan
2007-01-01
The principal goal of the book is to describe new accurate and robust algorithms for open resonant structures with substantially increased efficiency. These algorithms allow the extraction of complete information with estimated accuracy concerning the scattering of transient electromagnetic waves by complex objects. The determination and visualization of the electromagnetic fields, developed for realistic models, simplify and significantly speed up the solution to a wide class of fundamental and applied problems of electromagnetic field theory. The book presents a systematic approach to the study of electromagnetic waves scattering which can be introduced in undergraduate/postgraduate education in theoretical and applied radiophysics and different advanced engineering courses on antenna and wave-guide technology. On a broader level, the book should be of interest to scientists in optics, computational physics and applied mathematics.
Korompilias, Anastasios V; Karantanas, Apostolos H; Lykissas, Marios G; Beris, Alexandros E
2008-08-01
Transient osteoporosis is characterized primarily by bone marrow edema. The disease most commonly affects the hip, knee, and ankle in middle-aged men. Its cause remains unknown. The hallmark that separates transient osteoporosis from other conditions presenting with a bone marrow edema pattern is its self-limited nature. Laboratory tests usually do not contribute to the diagnosis. Plain radiographs may reveal regional osseous demineralization. Magnetic resonance imaging is used primarily for early diagnosis and monitoring disease progression. Early differentiation from more aggressive conditions with long-term sequelae is essential to avoid unnecessary treatment. Clinical entities such as transient osteoporosis of the hip and regional migratory osteoporosis are spontaneously resolving conditions. However, early differential diagnosis and surgical treatment are crucial for the patient with osteonecrosis of the hip or knee.
Transient analysis of an FHR coupled to a helium Brayton power cycle
Energy Technology Data Exchange (ETDEWEB)
Chen, Minghui [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Kim, In Hun [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Sun, Xiaodong [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Christensen, Richard [The Ohio State Univ., Columbus, OH (United States). Nuclear Engineering Program; Utgikar, Vivek [Univ. of Idaho, Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2015-08-01
The Fluoride salt-cooled High-temperature Reactor (FHR) features a passive decay heat removal system and a high-efficiency Brayton cycle for electricity generation. It typically employs an intermediate loop, consisting of an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX), to couple the primary system with the power conversion unit (PCU). In this study, a preliminary dynamic system model is developed to simulate transient characteristics of a prototypic 20-MW_{th} Fluoride salt-cooled High-temperature Test Reactor (FHTR). The model consists of a series of differential conservation equations that are numerically solved using the MATLAB platform. For the reactor, a point neutron kinetics model is adopted. For the IHX and SHX, a fluted tube heat exchanger and an offset strip-fin heat exchanger are selected, respectively. Detailed geometric parameters of each component in the FHTR are determined based on the FHTR nominal steady-state operating conditions. Three initiating events are simulated in this study, including a positive reactivity insertion, a step increase in the mass flow rate of the PCU helium flow, and a step increase in the PCU helium inlet temperature to the SHX. The simulation results show that the reactor has inherent safety features for those three simulated scenarios. It is observed that the increase in the temperatures of the fuel pebbles and primary coolant is mitigated by the decrease in the reactor power due to negative temperature feedbacks. The results also indicate that the intermediate loop with the two heat exchangers plays a significant role in the transient progression of the integral reactor system.
Humplík, Jan F; Lazár, Dušan; Husičková, Alexandra; Spíchal, Lukáš
2015-01-01
Current methods of in-house plant phenotyping are providing a powerful new tool for plant biology studies. The self-constructed and commercial platforms established in the last few years, employ non-destructive methods and measurements on a large and high-throughput scale. The platforms offer to certain extent, automated measurements, using either simple single sensor analysis, or advanced integrative simultaneous analysis by multiple sensors. However, due to the complexity of the approaches used, it is not always clear what such forms of plant phenotyping can offer the potential end-user, i.e. plant biologist. This review focuses on imaging methods used in the phenotyping of plant shoots including a brief survey of the sensors used. To open up this topic to a broader audience, we provide here a simple introduction to the principles of automated non-destructive analysis, namely RGB, chlorophyll fluorescence, thermal and hyperspectral imaging. We further on present an overview on how and to which extent, the automated integrative in-house phenotyping platforms have been used recently to study the responses of plants to various changing environments.
Energy Technology Data Exchange (ETDEWEB)
Pradhan, Santosh K., E-mail: santosh@aerb.gov.in [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India); Obaidurrahman, K. [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India); Iyer, Kannan N. [Department of Mechanical Engineering, IIT Bombay, Mumbai 400076 (India); Gaikwad, Avinash J. [Nuclear Safety Analysis Division, Atomic Energy Regulatory Board, Mumbai 400094 (India)
2016-04-15
Highlights: • A multi-point kinetics model is developed for RELAP5 system thermal hydraulics code. • Model is validated against extensive 3D kinetics code. • RELAP5 multi-point kinetics formulation is used to investigate critical break for LOCA in PHWR. - Abstract: Point kinetics approach in system code RELAP5 limits its use for many of the reactivity induced transients, which involve asymmetric core behaviour. Development of fully coupled 3D core kinetics code with system thermal-hydraulics is the ultimate requirement in this regard; however coupling and validation of 3D kinetics module with system code is cumbersome and it also requires access to source code. An intermediate approach with multi-point kinetics is appropriate and relatively easy to implement for analysis of several asymmetric transients for large cores. Multi-point kinetics formulation is based on dividing the entire core into several regions and solving ODEs describing kinetics in each region. These regions are interconnected by spatial coupling coefficients which are estimated from diffusion theory approximation. This model offers an advantage that associated ordinary differential equations (ODEs) governing multi-point kinetics formulation can be solved using numerical methods to the desired level of accuracy and thus allows formulation based on user defined control variables, i.e., without disturbing the source code and hence also avoiding associated coupling issues. Euler's method has been used in the present formulation to solve several coupled ODEs internally at each time step. The results have been verified against inbuilt point-kinetics models of RELAP5 and validated against 3D kinetics code TRIKIN. The model was used to identify the critical break in RIH of a typical large PHWR core. The neutronic asymmetry produced in the core due to the system induced transient was effectively handled by the multi-point kinetics model overcoming the limitation of in-built point kinetics model
Next Generation Nuclear Plant GAP Analysis Report
Energy Technology Data Exchange (ETDEWEB)
Ball, Sydney J [ORNL; Burchell, Timothy D [ORNL; Corwin, William R [ORNL; Fisher, Stephen Eugene [ORNL; Forsberg, Charles W. [Massachusetts Institute of Technology (MIT); Morris, Robert Noel [ORNL; Moses, David Lewis [ORNL
2008-12-01
As a follow-up to the phenomena identification and ranking table (PIRT) studies conducted recently by NRC on next generation nuclear plant (NGNP) safety, a study was conducted to identify the significant 'gaps' between what is needed and what is already available to adequately assess NGNP safety characteristics. The PIRT studies focused on identifying important phenomena affecting NGNP plant behavior, while the gap study gives more attention to off-normal behavior, uncertainties, and event probabilities under both normal operation and postulated accident conditions. Hence, this process also involved incorporating more detailed evaluations of accident sequences and risk assessments. This study considers thermal-fluid and neutronic behavior under both normal and postulated accident conditions, fission product transport (FPT), high-temperature metals, and graphite behavior and their effects on safety. In addition, safety issues related to coupling process heat (hydrogen production) systems to the reactor are addressed, given the limited design information currently available. Recommendations for further study, including analytical methods development and experimental needs, are presented as appropriate in each of these areas.
Belov, O A; Alekseeva, N N; Tavartkiladze, G A
2014-01-01
We have developed the new method for the analysis and visualization of the fine temporal structure of the transient evoked otoacoustic emission signal. The method consists of the presentation of the signal in the form of a set of tone components with a rapidly changing amplitude and relatively stable frequency. It is based on the combination of three spectrograms differing in frequency and temporal resolution by means of fuzzy logic amplitude estimation with subsequent frequency refining with the use of the least square procedure, reduction of the number of the insignificant components, and final re-ordering of the results for the simplification of further data processing. The new method was named Pitch Envelope Analysis (PEA). For data representation, a new type of diagram named componentogram was designed. The proposed method can be used for the real time processing of the continuous data stream especially for speech processing.
Tang, Bin
2008-01-01
A method has been developed for determining the transient response of a beam. The beam is divided into several continuous Timoshenko beam elements. The overall dynamic stiffness matrix is assembled in turn. Using Leung's equation, we derive the overall mass and stiffness matrices which are more suitable for response analysis than the overall dynamic stiffness matrix. The forced vibration of the beam is computed by the precise time integration method. Three illustrative beams are discussed to evaluate the performance of the current method. Solutions calculated by the finite element method and theoretical analysis are also enumerated for comparison. In these examples, we have found that the current method can solve the forced vibration of structures with a higher precision.
Comprehensive analysis of plant rapid alkalization factor (RALF) genes.
Sharma, Arti; Hussain, Adil; Mun, Bong-Gyu; Imran, Qari Muhammad; Falak, Noreen; Lee, Sang-Uk; Kim, Jae Young; Hong, Jeum Kyu; Loake, Gary John; Ali, Asad; Yun, Byung-Wook
2016-09-01
Receptor mediated signal carriers play a critical role in the regulation of plant defense and development. Rapid alkalization factor (RALF) proteins potentially comprise important signaling components which may have a key role in plant biology. The RALF gene family contains large number of genes in several plant species, however, only a few RALF genes have been characterized to date. In this study, an extensive database search identified 39, 43, 34 and 18 RALF genes in Arabidopsis, rice, maize and soybean, respectively. These RALF genes were found to be highly conserved across the 4 plant species. A comprehensive analysis including the chromosomal location, gene structure, subcellular location, conserved motifs, protein structure, protein-ligand interaction and promoter analysis was performed. RALF genes from four plant species were divided into 7 groups based on phylogenetic analysis. In silico expression analysis of these genes, using microarray and EST data, revealed that these genes exhibit a variety of expression patterns. Furthermore, RALF genes showed distinct expression patterns of transcript accumulation in vivo following nitrosative and oxidative stresses in Arabidopsis. Predicted interaction between RALF and heme ligand also showed that RALF proteins may contribute towards transporting or scavenging oxygen moieties. This suggests a possible role for RALF genes during changes in cellular redox status. Collectively, our data provides a valuable resource to prime future research in the role of RALF genes in plant growth and development.
Real-time analysis of water movement in plant sample
Energy Technology Data Exchange (ETDEWEB)
Yokota, Harumi; Furukawa, Jun; Tanoi, Keitaro [Graduate School, Tokyo Univ. (Japan)
2000-07-01
To know the effect of drought stress on two cultivars of cowpea, drought tolerant (DT) and drought sensitive (DS), and to estimate vanadium treatment on plant activity, we performed real time{sup 18}F labeled water uptake measurement by PETIS. Fluoride-18 was produced by bombarding a cubic ice target with 50 MeV protons using TIARA AVF cyclotron. Then {sup 18}F labeled water was applied to investigate water movement in a cowpea plant. Real time water uptake manner could be monitored by PETIS. After the analysis by PETIS, we also measured the distribution of {sup 18}F in a whole plant by BAS. When a cowpea plant was treated with drought stress, there was a difference in water uptake manner between DT and DS cultivar. When a cowpea plant was treated with V for 20 hours before the water uptake experiment, the total amount of {sup 18}F labeled water absorption was found to be drastically decreased. (author)
Graphical analysis of French nuclear power plant production date
Energy Technology Data Exchange (ETDEWEB)
Jourdan, J.P. [Electricite de France (EDF), Projet Production EPR 1, 93 - Saint-Denis (France)
2001-07-01
The analysis of values of plant production uses here an original method of graphical analysis. This method clarifies various difficulties of analysing big experience feedback databases among which the language interpretation and distinctions between scarce events and multi-annual events. In general, the method shows the logical processes that production values obey (pure chance logic, administrative logic, and willpower) This method of graphical analysis provides a tool to observe and question in a concrete way so that each person involved can put the events in which he played a role into the general context of other plants. It is a deductible method to improve this big and complex system. (author)
Institute of Scientific and Technical Information of China (English)
LAN Hengxing; ZHOU Chenghu; C.F.Lee; WANG Sijing; WU Faquan
2003-01-01
Transient pore pressure in response to short intense rainfall process plays an important role in shallow landslide occurrence. Using GIS technology, we carry out the rainfall-induced landslide stability analysis in response to transient pore pressure by means of transient and unsaturated rainfall infiltration modeling. A case study is performed on the shallow landslide stability analysis in Hong Kong. Detailed analysis and discussion reached some useful conclusions on the tempo-spatial behavior and characteristics of slope stability response and pore pressure response to typical rainfall process. Comparison analysis is performed on some important issues including landslide stability response in different types of slopes with different hydraulic properties, antecedent rainfall and landslide stability, and the nature of pore pressure response time. These studies might give us an important insight into landslide tringgering mechanism and the hydrological process in response to rainfall, and provide systematic information and evidences for effective risk assessment and warning system establishment.
Chin, Jeffrey C.; Csank, Jeffrey T.
2016-01-01
The Tool for Turbine Engine Closed-Loop Transient Analysis (TTECTrA ver2) is a control design tool thatenables preliminary estimation of transient performance for models without requiring a full nonlinear controller to bedesigned. The program is compatible with subsonic engine models implemented in the MATLAB/Simulink (TheMathworks, Inc.) environment and Numerical Propulsion System Simulation (NPSS) framework. At a specified flightcondition, TTECTrA will design a closed-loop controller meeting user-defined requirements in a semi or fully automatedfashion. Multiple specifications may be provided, in which case TTECTrA will design one controller for each, producing acollection of controllers in a single run. Each resulting controller contains a setpoint map, a schedule of setpointcontroller gains, and limiters; all contributing to transient characteristics. The goal of the program is to providesteady-state engine designers with more immediate feedback on the transient engine performance earlier in the design cycle.
Economic analysis of large solar power plants
Klaiss, Helmut; Nitsch, Joachim; Geyer, Michael
1987-11-01
The current status and future potential of solar-tower, parabolic-reflector/Stirling-engine, channel-collector, and photovoltaic solar power plants of capacity 10 MWe or more are discussed. Consideration is given to the geographic and technological limitations, initial investment and operating costs, presently operating facilities, market openings, and critical technological challenges controlling future expansion. Numerical data are presented in tables and graphs, and it is concluded that solar power production will soon become economically competitive. It is suggested that the channel collector, at present the most mature and cost-efficient technology, has the least potential for further improvement, and that parabolic/Stirling and photovoltaic systems are probably better suited to smaller applications than to large-scale commercial power production.
Tournier, Jean-Michel; El-Genk, Mohamed S.
1995-01-01
A two-dimensional Heat Pipe Transient Analysis Model, 'HPTAM,' was developed to simulate the transient operation of fully-thawed heat pipes and the startup of heat pipes from a frozen state. The model incorporates: (a) sublimation and resolidification of working fluid; (b) melting and freezing of the working fluid in the porous wick; (c) evaporation of thawed working fluid and condensation as a thin liquid film on a frozen substrate; (d) free-molecule, transition, and continuum vapor flow regimes, using the Dusty Gas Model; (e) liquid flow and heat transfer in the porous wick; and (f) thermal and hydrodynamic couplings of phases at their respective interfaces. HPTAM predicts the radius of curvature of the liquid meniscus at the liquid-vapor interface and the radial location of the working fluid level (liquid or solid) in the wick. It also includes the transverse momentum jump condition (capillary relationship of Pascal) at the liquid-vapor interface and geometrically relates the radius of curvature of the liquid meniscus to the volume fraction of vapor in the wick. The present model predicts the capillary limit and partial liquid recess (dryout) in the evaporator wick, and incorporates a liquid pooling submodel, which simulates accumulation of the excess liquid in the vapor core at the condenser end.
Mcgowan, David M.; Bostic, Susan W.; Camarda, Charles J.
1993-01-01
The development of two advanced reduced-basis methods, the force derivative method and the Lanczos method, and two widely used modal methods, the mode displacement method and the mode acceleration method, for transient structural analysis of unconstrained structures is presented. Two example structural problems are studied: an undamped, unconstrained beam subject to a uniformly distributed load which varies as a sinusoidal function of time and an undamped high-speed civil transport aircraft subject to a normal wing tip load which varies as a sinusoidal function of time. These example problems are used to verify the methods and to compare the relative effectiveness of each of the four reduced-basis methods for performing transient structural analyses on unconstrained structures. The methods are verified with a solution obtained by integrating directly the full system of equations of motion, and they are compared using the number of basis vectors required to obtain a desired level of accuracy and the associated computational times as comparison criteria.
Malkinson, Guy; Spira, Micha E
2010-04-01
The use of the sensory-motor (SN-MN) synapse of the Aplysia gill withdrawal reflex has contributed immensely to the understanding of synaptic transmission, learning and memory acquisition processes. Whereas the majority of the studies focused on analysis of the presynaptic mechanisms, recent studies indicated that as in mammalian synapses, long term potentiation (LTP) formed by Aplysia SN-MN synapse depends on elevation of the postsynaptic free intracellular calcium concentration ([Ca2+](i)). Consistently, injection of the fast calcium chelator BAPTA to the MN prevents the formation of serotonin-induced LTP. Nevertheless, currently there are no published reports that directly examine and document whether evoked synaptic transmission is associated with transient increase in the postsynaptic [Ca2+](i). In the present study we imaged, for the first time, alterations in the postsynaptic [Ca2+](i) in response to presynaptic stimulation and analyzed the underlying mechanisms. Using live imaging of the postsynaptic [Ca2+](i) while monitoring the EPSP, we found that evoked transmitter release generates excitatory postsynaptic calcium concentration transients (EPSCaTs) by two mechanisms: (a) activation of DNQX-sensitive postsynaptic receptors-gated calcium influx and (b) calcium influx through nitrendipine-sensitive voltage-gated calcium channels (VGCCs). Concomitant confocal imaging of presynaptic boutons and EPSCaTs revealed that approximately 86% of the presynaptic boutons are associated with functional synapses.
Holland, V; Koller, S; Brüggemann, W
2014-07-01
Climate change is one of the major issues nowadays, and Mediterranean broadleaf species have been suggested to fill possible future gaps created by climate change in Central European forests. To provide a scientific-based foundation for such practical strategies, it is important to obtain a general idea about differences and similarities in the physiology of Central European and Mediterranean species. In the present study, we evaluated the onset of leaf senescence of a broad spectrum of oak species under the Central European climate in a common garden experiment. Degradation of the photosynthetic apparatus of evergreen (Quercus ilex, Q. suber), semi-evergreen (Q.×turneri, Q.×hispanica) and deciduous oaks (Q. robur, Q. cerris, Q. frainetto, Q. pubescens) was monitored as chlorophyll content and analysed chlorophyll fluorescence induction transients. In the deciduous species, a significant decline in chlorophyll content was observed during autumn/winter, with Q. pubescens showing the slowest decline. Analysis of fluorescence induction transients revealed a significant decline in quantum efficiency of the primary photochemistry and reaction centre density and later, a decrease in quantum efficiency of end acceptor reduction. Alterations in fluorescence parameters were compared to the decline in chlorophyll content, which occurred much more slowly than expected from the fluorescence data. The evergreen species showed no decline in chlorophyll content, nor different chlorophyll a fluorescence induction behaviour despite temperature falling below 0 °C. The hybrids showed intermediate behaviour between their parental evergreen and deciduous taxa.
Directory of Open Access Journals (Sweden)
Zhiming Yang
2016-01-01
Full Text Available The reliability of Very Large Scale Integration (VLSI circuits has become increasingly susceptible to transient faults induced by environmental noise with the scaling of technology. Some commonly used fault tolerance strategies require statistical methods to accurately estimate the fault rate in different parts of the logic circuit, and Monte Carlo (MC simulation is often applied to complete this task. However, the MC method suffers from impractical computation costs due to the size of the circuits. Furthermore, circuit aging effects, such as negative bias temperature instability (NBTI, will change the characteristics of the circuit during its lifetime, leading to a change in the circuit’s noise margin. This change will increase the complexity of transient fault rate estimation tasks. In this paper, an NBTI-aware statistical analysis method based on probability voltage transfer characteristics is proposed for combinational logic circuit. This method can acquire accurate fault rates using a discrete probability density function approximation process, thus resolving the computation cost problem of the MC method. The proposed method can also consider aging effects and analyze statistical changes in the fault rates. Experimental results demonstrate that, compared to the MC simulation, our method can achieve computation times that are two orders of magnitude shorter while maintaining an error rate less than 9%.
Integrated Network Analysis and Effective Tools in Plant Systems Biology
Directory of Open Access Journals (Sweden)
Atsushi eFukushima
2014-11-01
Full Text Available One of the ultimate goals in plant systems biology is to elucidate the genotype-phenotype relationship in plant cellular systems. Integrated network analysis that combines omics data with mathematical models has received particular attention. Here we focus on the latest cutting-edge computational advances that facilitate their combination. We highlight (1 network visualization tools, (2 pathway analyses, (3 genome-scale metabolic reconstruction, and (4 the integration of high-throughput experimental data and mathematical models. Multi-omics data that contain the genome, transcriptome, proteome, and metabolome and mathematical models are expected to integrate and expand our knowledge of complex plant metabolisms.
Institute of Scientific and Technical Information of China (English)
万秋兰; 单渊达
2001-01-01
基于李雅普诺夫稳定理论，对用于电力系统暂态稳定分析的暂态能量函数法进行了分析，认为可定量分析和快速性是其独特优势，不可靠性是其局限性。提出了暂态能量函数法用于非自治系统所必须满足的条件，包括用临界轨迹确定临界能量，以及用临界轨迹得到的切除时间确定故障清除后的稳定平衡点等。尽管目前暂态能量函数法只作为电力系统暂态稳定分析的辅助工具，但如何提高它的可靠性并将其应用到非自治系统仍是有待深入研究的课题。%Based on the Lyapunov stability theory, this paper analyzes thetransient energy function methods for power system transient stability analysis, and considers the quantitative analysis and fast speed as their advantages, but the unreliability as their limitations. The demands that transient energy function methods must meet for the non-autonomous motion system are also proposed, which include that the critical energy should be determined by the critical trajectory and the post-fault stable equilibrium point should be determined by the critical clearing time. Although the transient energy function methods are only used as the auxiliary tool at present for the power system transient stability analysis, how to improve its reliability and apply it to the non-autonomous motion system is still an attractive topic that needs to be deeply researched.
Analysis of hot spots in boilers of organic Rankine cycle units during transient operation
DEFF Research Database (Denmark)
Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo
2015-01-01
This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycle...... unit toincrease the overall energy conversion efficiency.The dynamic model of the plant is coupled with a one-dimensional model of the once-through boilerfed by the exhaust thermal power of the gas turbine. The heat exchanger model uses a distributedcross-flow physical topology and local correlations...... and fluid decomposition. It is demonstrated thatthe use of a spray attemperator can mitigate the problems of local overheating of the organic compound.As a practical consequence, this paper provides guidelines for safe and reliable operation of organicRankine cycle power modules on offshore installations....
PRONTO3D users` instructions: A transient dynamic code for nonlinear structural analysis
Energy Technology Data Exchange (ETDEWEB)
Attaway, S.W.; Mello, F.J.; Heinstein, M.W.; Swegle, J.W.; Ratner, J.A. [Sandia National Labs., Albuquerque, NM (United States); Zadoks, R.I. [Univ. of Texas, El Paso, TX (United States)
1998-06-01
This report provides an updated set of users` instructions for PRONTO3D. PRONTO3D is a three-dimensional, transient, solid dynamics code for analyzing large deformations of highly nonlinear materials subjected to extremely high strain rates. This Lagrangian finite element program uses an explicit time integration operator to integrate the equations of motion. Eight-node, uniform strain, hexahedral elements and four-node, quadrilateral, uniform strain shells are used in the finite element formulation. An adaptive time step control algorithm is used to improve stability and performance in plasticity problems. Hourglass distortions can be eliminated without disturbing the finite element solution using either the Flanagan-Belytschko hourglass control scheme or an assumed strain hourglass control scheme. All constitutive models in PRONTO3D are cast in an unrotated configuration defined using the rotation determined from the polar decomposition of the deformation gradient. A robust contact algorithm allows for the impact and interaction of deforming contact surfaces of quite general geometry. The Smooth Particle Hydrodynamics method has been embedded into PRONTO3D using the contact algorithm to couple it with the finite element method.
ULTRAVIOLET SPECTROSCOPIC ANALYSIS OF TRANSIENT MASS FLOW OUTBURST IN U CEPHEI
Energy Technology Data Exchange (ETDEWEB)
Tupa, Peter R.; DeLeo, Gary G.; McCluskey, George E. [Physics Department, Lehigh University, Bethlehem, PA 18015 (United States); Kondo, Yoji [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sahade, Jorge [Facultad de Ciencias Astronómicas, Paseo del Bosque s/n, B1900FWA-La Plata (Argentina); Giménez, Alvaro [Centro de Astrobiologia, CSIC/INTA, Carretera de Torrejon a Ajalvir, E-28850 Torrejon de Ardoz (Madrid) (Spain); Caton, Daniel B., E-mail: pet205@lehigh.edu [Appalachian State University, Boone, NC 28608 (United States)
2013-09-20
Spectra from the International Ultraviolet Explorer taken in 1989 September over one full orbital period of U Cephei (U Cep, HD 5796) are analyzed. The TLUSTY and SYNSPEC stellar atmospheric simulation programs are used to generate synthetic spectra to which U Cep continuum levels are normalized. Absorption lines attributed to the photosphere are divided out to isolate mass flow and accretion spectra. A radial velocity curve is constructed for conspicuous gas stream features, and shows evidence for a transient flow during secondary eclipse with outward velocities ranging between 200 and 350 km s{sup –1}, and a number density of (3 ± 2) × 10{sup 10} cm{sup –3}. The validity of C IV 1548 and 1550 and Si IV 1393 and 1402 lines are re-examined in the context of extreme rotational blending effects. A G-star to B-star mass transfer rate of (5 ± 4) × 10{sup –9} M{sub ☉} yr{sup –1} is calculated as an approximate upper limit, and a model system is presented.
McNally, Richard J Q; Rankin, Judith; Shirley, Mark D F; Rushton, Stephen P; Pless-Mulloli, Tanja
2008-10-01
Whilst maternal age is an established risk factor for Patau syndrome (trisomy 13), Edwards syndrome (trisomy 18) and Down syndrome (trisomy 21), the aetiology and contribution of genetic and environmental factors remains unclear. We analysed for space-time clustering using high quality fully population-based data from a geographically defined region. The study included all cases of Patau, Edwards and Down syndrome, delivered during 1985-2003 and resident in the former Northern Region of England, including terminations of pregnancy for fetal anomaly. We applied the K-function test for space-time clustering with fixed thresholds of close in space and time using residential addresses at time of delivery. The Knox test was used to indicate the range over which the clustering effect occurred. Tests were repeated using nearest neighbour (NN) thresholds to adjust for variable population density. The study analysed 116 cases of Patau syndrome, 240 cases of Edwards syndrome and 1084 cases of Down syndrome. There was evidence of space-time clustering for Down syndrome (fixed threshold of close in space: P = 0.01, NN threshold: P = 0.02), but little or no clustering for Patau (P = 0.57, P = 0.19) or Edwards (P = 0.37, P = 0.06) syndromes. Clustering of Down syndrome was associated with cases from more densely populated areas and evidence of clustering persisted when cases were restricted to maternal age syndrome suggests an aetiological role for transient environmental factors, such as infections.
Transient heat conduction in a solid slab using multiple-scale analysis
Energy Technology Data Exchange (ETDEWEB)
Bautista, O.; Campos, I. [ITESM, Division de Ingenieria y Arquitectura, Mexico, DF (Mexico); Mendez, F. [UNAM, Facultad de Ingenieria, Mexico, DF (Mexico)
2005-12-01
In this paper we study the unsteady heat conduction due to a sudden temperature step in the external surfaces of a solid slab. In order to estimate the temperature profile in the solid, we applied the multiple-scale perturbation technique by identifying the ''early'' and ''late'' transient regimes for small values of the Biot number, Bi. In this sense, we have re-visited the classical lumped method, incorporating this particular case as an asymptotic limit, which is fully described by the ''late'' regime for small values of Bi. Once the temperature distribution is analytically predicted, this solution is compared against the exact solution and with other analytical results obtained by using regular perturbation techniques, for different values of the Biot number Bi. Observing a good agreement between the corresponding comparisons, we obtain a very simple and useful formula to predict the nondimensional temperature of the solid slab. (orig.)
Time-variant power spectrum analysis for the detection of transient episodes in HRV signal.
Bianchi, A M; Mainardi, L; Petrucci, E; Signorini, M G; Mainardi, M; Cerutti, S
1993-02-01
A time-variant algorithm of autoregressive (AR) identification is introduced and applied to the heart rate variability (HRV) signal. The power spectrum is calculated from the AR coefficients derived from each single RR interval considered. Time-variant AR coefficients are determined through adaptive parametric identification with a forgetting factor which obtains weighed values on a running temporal window of 50 preceding measurements. Power spectrum density (PSD) is hence obtained at each cardiac cycle, making it possible to follow the dynamics of the spectral parameters on a beat-by-beat basis. These parameters are mainly the LF (low frequency) and the HF (high frequency) powers, and their ratio LF/HF. These together account for the balanced sympatho-vagal control mechanism affecting the heart rate. This method is applied to subjects suffering from transient ischemic attacks. The time variant spectral parameters suggest an early activation of LF component in the HRV power spectrum. It precedes by approximately 1.5-2 min the tachycardia and the ST displacement, generally indicative of the onset of an ischemic episode. The results suggest an arousal of sympathetic system before the acute attack.
Non-modal stability analysis and transient growth in a magnetized Vlasov plasma
Ratushnaya, V.
2014-12-01
Collisionless plasmas, such as those encountered in tokamaks, exhibit a rich variety of instabilities. The physical origin, triggering mechanisms and fundamental understanding of many plasma instabilities, however, are still open problems. We investigate the stability properties of a 3-dimensional collisionless Vlasov plasma in a stationary homogeneous magnetic field. We narrow the scope of our investigation to the case of Maxwellian plasma and examine its evolution with an electrostatic approximation. For the first time using a fully kinetic approach we show the emergence of the local instability, a transient growth, followed by classical Landau damping in a stable magnetized plasma. We show that the linearized Vlasov operator is non-normal leading to the algebraic growth of the perturbations using non-modal stability theory. The typical time scales of the obtained instabilities are of the order of several plasma periods. The first-order distribution function and the corresponding electric field are calculated and the dependence on the magnetic field and perturbation parameters is studied. Our results offer a new scenario of the emergence and development of plasma instabilities on the kinetic scale.